WO2025025035A1

WO2025025035A1 - Two-step conditional lower-layer triggered mobility (ltm) procedures

Info

Publication number: WO2025025035A1
Application number: PCT/CN2023/110134
Authority: WO
Inventors: Qiaoyu Li; Jelena Damnjanovic; Mahmoud Taherzadeh Boroujeni
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2023-07-31
Filing date: 2023-07-31
Publication date: 2025-02-06
Anticipated expiration: 2026-01-31

Abstract

Certain aspects of the present disclosure relate to real-time beam prediction and reporting in conditional lower-layer triggered mobility (LTM) procedures. A method includes sending, at a first time, a first conditional LTM message comprising a request for a user equipment (UE) to switch from communicating on a source cell to communicating on a target cell, sending, at a second time after the first time, a second conditional LTM message comprising one of: a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Description

TWO-STEP CONDITIONAL LOWER-LAYER TRIGGERED MOBILITY (LTM) PROCEDURES

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for lower-layer triggered mobility (LTM) .

Description of Related Art

Wireless communications systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available wireless communications system resources with those users.

Although wireless communications systems have made great technological advancements over many years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Accordingly, there is a continuous desire to improve the technical performance of wireless communications systems, including, for example: improving speed and data carrying capacity of communications, improving efficiency of the use of shared communications mediums, reducing power used by transmitters and receivers while performing communications, improving reliability of wireless communications, avoiding redundant transmissions and/or receptions and related processing, improving the coverage area of wireless communications, increasing the number and types of devices that can access wireless communications systems, increasing the ability for different types of devices to intercommunicate, increasing the number and type of wireless communications mediums available for use, and the like. Consequently, there exists a need for further improvements in wireless communications systems to overcome the aforementioned technical challenges and others.

SUMMARY

Lower-layer triggered mobility (LTM) procedures are handover procedures used to transfer a user equipment (UE) from a source cell to a target cell while in a connected state, specifically via lower layer signaling (e.g., layer 1 (L1) /layer 2 (L2) signaling) . Conditional LTM procedures are a type of LTM procedure where the cell switch is initiated by the UE, itself. For example, a UE may be configured to measure and/or predict (e.g., using a machine learning (ML) model and/or other prediction techniques) channel characteristics of a source cell and channel characteristics of a target cell. Based on these measured and/or predicted channel characteristics, the UE may decide to switch its connection from the source cell to the target cell (e.g., due to a predicted beam failure at the source cell, greater reference signal received power (RSRP) at the target cell, etc. ) . Accordingly, the UE may trigger the initiation of the conditional LTM procedure by transmitting a conditional LTM message requesting to switch from communicating on the source cell to communicating on the target cell.

In some cases, where communication resources are measured and/or predicted by the UE and used by the UE to decide that a handover to a target cell is warranted, it may be beneficial for the UE to also provide an indication of one or more of these communication resources to the target cell during the conditional LTM procedure. Notifying the network entity of the target cell about a communication resource may allow the network entity of the target cell to determine an uplink receive beam and/or downlink transmit beam, of the network entity, associated with the communication resource that may be used for communication with the UE, after completion of the conditional LTM procedure. As such, the performance of additional beam management procedures (e.g., for determining a most suitable beam pair for communication) , such as beam sweeping and/or beam refinement, may not be necessary after the conditional LTM procedure has completed.

However, providing this indication of a communication resource may not be feasible for some LTM procedures. In particular, transmission of the indication of a communication resource from the UE to the network entity of the source cell, and then from the network entity of the source cell to the network entity of the target cell (e.g., via non-ideal backhaul) , may take a longer amount of time than a duration configured for a timer used in some conditional LTM procedures. In particular, a timer used in such procedures may allow a UE enough time to prepare and execute the cell switch, and at an expiration of the timer, the UE may be expected to be connected to the target cell. The timer period set for the timer may not, however, account for non-ideal backhaul delay between the network entity of the source cell and the network entity of the target cell such that the network entity of the source cell has enough time to inform the network entity of the target cell about the communication resource provided to the network entity of the source cell from the UE. As such, beam management procedures may be necessary to determine one or more beam pairs for communication between the network entity of the target cell and the UE after the UE has switched from the source cell to the target cell. Needing to perform additional beam sweeping and/or beam refinement procedures, after the UE has switched cells and is connected to the target cell may result in additional throughput interruption at the UE, at least until a beam pair capable of providing sufficient throughput performance for communications between the network entity of the target cell and the UE is determined.

Certain aspects of the present disclosure provide a technical solution to the aforementioned technical problems by providing techniques for performing a two-step LTM procedure where two conditional LTM messages are sent (instead of one conditional LTM message, as done in conventional procedures) .

One aspect provides a method for wireless communications by an apparatus. The method includes sending, at a first time, a first conditional lower-layer triggered mobility (LTM) message comprising a request for the apparatus to switch from communicating on a source cell to communicating on a target cell; and sending, at a second time after the first time, a second conditional LTM message comprising one of: a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Another aspect provides a method for wireless communications by an apparatus. The method includes receiving, at a first time, a first conditional LTM message comprising a request for a user equipment (UE) to switch from communicating on a source cell to communicating on a target cell of the apparatus; and receiving, at a second time after the first time, a second conditional LTM message comprising one off a confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.

Other aspects provide: one or more apparatuses operable, configured, or otherwise adapted to perform any portion of any method described herein (e.g., such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses) ; one or more non-transitory, computer-readable media comprising instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform any portion of any method described herein (e.g., such that instructions may be included in only one computer-readable medium or in a distributed fashion across multiple computer-readable media, such that instructions may be executed by only one processor or by multiple processors in a distributed fashion, such that each apparatus of the one or more apparatuses may include one processor or multiple processors, and/or such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses) ; one or more computer program products embodied on one or more computer-readable storage media comprising code for performing any portion of any method described herein (e.g., such that code may be stored in only one computer-readable medium or across computer-readable media in a distributed fashion) ; and/or one or more apparatuses comprising one or more means for performing any portion of any method described herein (e.g., such that performance would be by only one apparatus or by multiple apparatuses in a distributed fashion) . By way of example, an apparatus may comprise a processing system, a device with a processing system, or processing systems cooperating over one or more networks.

The following description and the appended figures set forth certain features for purposes of illustration.

BRIEF DESCRIPTION OF DRAWINGS

The appended figures depict certain features of the various aspects described herein and are not to be considered limiting of the scope of this disclosure.

FIG. 1 depicts an example wireless communications network.

FIG. 2 depicts an example disaggregated base station architecture.

FIG. 3 depicts aspects of an example base station and an example user equipment (UE) .

FIGS. 4A, 4B, 4C, and 4D depict various example aspects of data structures for a wireless communications network.

FIG. 5 is a diagram depicting an example of beam management.

FIG. 6 is a diagram depicting examples of beam management procedures.

FIG. 7 is a diagram depicting example architecture of a functional framework for radio access network (RAN) intelligence enabled by data collection.

FIGS. 8A and 8B are diagrams depicting example communication resource prediction for beam selection by a UE.

FIG. 9 depicts an example lower-layer triggered mobility (LTM) procedure.

FIGS. 10A and 10B depict issues with informing target cells of predicted beams in existing conditional LTM procedures.

FIGS. 11A and 11B illustrate example real-time beam prediction and reporting (e.g., via non-idea backhaul) in conditional LTM procedures.

FIG. 12 illustrates a duration of a first timer in a conditional LTM procedure determined based on an indication of the duration transmitted via a first type of message.

FIG. 13 illustrates a duration of a first timer in a conditional LTM procedure determined based on an indication of the duration transmitted via other types of messages.

FIG. 14 illustrates a duration of a first timer in a conditional LTM procedure determined based on a UE-recommended duration.

FIG. 15 illustrates examples for determining a duration of a first timer in a conditional LTM procedure, specifically for cases where a target cell involved in the conditional LTM procedure performs time domain beam prediction.

FIG. 16 illustrates examples for determining a duration of a first timer in a conditional LTM procedure, specifically for cases where a source cell involved in the conditional LTM procedure performs time domain beam prediction.

FIG. 17 depicts example triggering of first and/or second conditional LTM messages based on one or more conditions.

FIG. 18 depicts a method for wireless communications.

FIG. 19 depicts another method for wireless communications.

FIG. 20 depicts aspects of an example communications device.

FIG. 21 depicts aspects of an example communications device.

DETAILED DESCRIPTION

Aspects of the present disclosure relate to techniques for conditional lower-layer triggered mobility (LTM) procedures. Certain aspects relate to real-time beam prediction and reporting, via non-idea backhaul. LTM procedures are handover procedures used to transfer a user equipment (UE) from a source cell to a target cell while in a connected state, specifically via lower layer signaling (e.g., layer 1 (L 1) /layer 2 (L2) signaling) . Conditional LTM procedures are a type of LTM procedure where the cell switch is initiated by the UE, itself. In particular, a UE being connected to, communicating with, or communicating in, a cell may refer to the UE being connected to a network entity and communicating with the network entity in a particular frequency range. A network entity may provide coverage in more than one cell, such as where the network entity communicates with UEs in different frequency ranges. Accordingly, a UE transferring from a source cell to a target cell may refer to the UE transferring from communicating with a first network entity in a first frequency range, to communicating with the first network entity in a second frequency range. As another example, a UE transferring from a source cell to a target cell may refer to the UE transferring from communicating with a first network entity in a first frequency range, to communicating with a second network entity in the first frequency range or a second frequency range.

For example, a UE may be configured to measure and/or predict (e.g., using a machine learning (ML) model and/or other prediction techniques) channel characteristics of a source cell and channel characteristics of a target cell. Based on these measured and/or predicted channel characteristics, the UE may decide to switch its connection from the source cell to the target cell (e.g., due to a predicted beam failure at the source cell, greater reference signal received power (RSRP) at the target cell, etc. ) . Accordingly, the UE may trigger the initiation of the conditional LTM procedure by transmitting a conditional LTM message requesting to switch from communicating on the source cell to communicating on the target cell.

An example conditional LTM procedure may involve starting a timer after transmission of the conditional LTM message by the UE or after a confirmation message is received at the UE in response to transmitting the message triggering the procedure. A duration set for the timer may be a fixed value and/or dynamically configured, and may take into consideration an amount of time needed by the UE and/or one or more network entities (e.g., associated with the source cell and/or the target cell) to prepare for and carry out the switch. In particular, the UE is expected to switch from the source cell to the target cell within the duration allotted by the timer.

In some cases, where communication resources are measured and/or predicted by the UE and used by the UE to decide that a handover to a target cell is warranted, it may be beneficial for the UE to also provide an indication of one or more of these communication resources to the target cell during the conditional LTM procedure. For example, the UE may provide to a network entity of the target cell an indication of a communication resource the UE determines has a predicted or actually measured channel characteristic (e.g., RSRP) that meets a criteria (e.g., threshold, highest amongst multiple communication resources, etc. ) . Where a communication resource is actually measured, a network entity of the target cell may transmit a signal in the communication resource using a downlink transmit beam of the target cell, and the UE may receive and measure the signal using a downlink receive beam of the UE.

In particular, notifying the network entity of the target cell about a communication resource may allow the network entity of the target cell to determine an uplink receive beam and/or downlink transmit beam, of the network entity, associated with the communication resource that may be used for communication with the UE, after completion of the conditional LTM procedure. For example, the communication resource may be associated with a downlink transmit beam of the network entity, such that transmission on the communication resource by the network entity is actually or would be performed using the downlink transmit beam. The downlink transmit beam may be associated with (e.g., quasi-co-located with) an uplink receive beam of the network entity, such that the uplink receive beam of the network entity is also associated with the communication resource.

Further, the UE may use a downlink receive beam and/or uplink transmit beam, of the UE, associated with the communication resource, to communicate with the network entity of the target cell, after completion of the conditional LTM procedure. For example, the communication resource may be associated with a downlink receive beam of the UE, such that reception on the communication resource by the UE is actually or would be performed using the downlink receive beam. The downlink receive beam may be associated with (e.g., quasi-co-located with) an uplink transmit beam of the UE, such that the uplink transmit beam of the UE is also associated with the communication resource.

As such, the performance of additional beam management procedures (e.g., for determining a most suitable beam pair for communication) , such as beam sweeping and/or beam refinement, may not be necessary, thereby saving time and resources at both the target cell and the UE, and thus improving overall connectivity and reliability of wireless communications between these entities. A beam pair includes a transmit beam and a corresponding receive beam in one link direction. For example, for uplink communications, a beam pair may include a UE transmit beam and a network entity of a target cell receive beam (corresponding to a receive beam of a network entity providing coverage in the target cell) . For downlink communications, a beam pair may include a UE receive beam and a network entity of a target cell transmit beam (corresponding to a transmit beam of a network entity providing coverage in the target cell) .

However, providing this indication of a communication resource may not be feasible in existing LTM procedures. In particular, transmission of the indication of a communication resource from the UE to the network entity of the source cell, and then from the network entity of the source cell to the network entity of the target cell (e.g., via non-ideal backhaul) , may take a longer amount of time than the duration configured for the timer. More specifically, the timer period set for the timer may not account for non-ideal backhaul between the network entity of the source cell and the network entity of the target cell such that the network entity of the source cell has enough time to inform the network entity of the target cell about the communication resource provided to the network entity of the source cell from the UE. As such, beam management procedures may be necessary to determine one or more beam pairs for communication between the network entity of the target cell and the UE after the UE has switched from the source cell to the target cell. Needing to perform additional beam sweeping and/or beam refinement procedures, after the UE has switched cells and is connected to the target cell may result in additional throughput interruption at the UE, at least until a beam pair capable of providing sufficient throughput performance for communications between the network entity of the target cell and the UE is determined.

Certain aspects of the present disclosure provide a technical solution to the aforementioned technical problems by providing techniques for performing a two-step LTM procedure where two conditional LTM messages are sent (instead of one conditional LTM message, as done in conventional procedures) . For example, a first conditional LTM message may be transmitted at a first time, by a UE, requesting that the UE switch from communicating on a source cell to communicating on a target cell. Further, a second conditional LTM message may be transmitted at a second time (e.g. later in time than the first time) to either (1) confirm or (2) request the cancellation of the earlier request to perform the cell switch. Each of the two conditional LTM messages may trigger the initiation of a timer. For example, the first conditional message may trigger a first timer, and at the expiration of the first timer, the second conditional LTM message may be sent. In cases where the second conditional LTM message confirms the cell switch procedure, then a second timer may also be triggered. A duration of the second timer may be set to provide the UE and the target cell with a sufficient amount of time to prepare for and carry out the cell switch.

The introduction of the first timer in the conditional LTM procedure, according to aspects described herein, however, helps to extend the time period from when a first conditional LTM message is sent by the UE to when the UE is expected at the target cell (e.g., when the UE is expected to be connected to and in communication with the target cell) . This additional time, provided via use of the first timer, may provide sufficient time to notify the network entity of the target cell of one or more communication resources (e.g., associated with beams of the target cell) such that beam management procedures, following successful synchronization of the network entity of the target cell with the UE, can be avoided. Instead, communication between the UE and the network entity of the target cell following completion of the conditional LTM procedure may be based on the one or more communication resources indicated to the network entity of the target cell.

Notably, in certain aspects, the improved conditional LTM procedures described herein using two conditional LTM messages, and in some cases, two timers, have the beneficial technical effect of allowing for non-ideal backhaul signaling prior to completion of the procedure, thereby improving overall throughput, reliability, and efficiency of wireless communications between a target cell and a UE after the cell switch is complete.

Introduction to Wireless Communications Networks

The techniques and methods described herein may be used for various wireless communications networks. While aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure may likewise be applicable to other communications systems and standards not explicitly mentioned herein.

FIG. 1 depicts an example of a wireless communications network 100, in which aspects described herein may be implemented.

Generally, wireless communications network 100 includes various network entities (alternatively, network elements or network nodes) . A network entity is generally a communications device and/or a communications function performed by a communications device (e.g., a user equipment (UE) , a base station (BS) , a component of a BS, a server, etc. ) . As such communications devices are part of wireless communications network 100, and facilitate wireless communications, such communications devices may be referred to as wireless communications devices. For example, various functions of a network as well as various devices associated with and interacting with a network may be considered network entities. Further, wireless communications network 100 includes terrestrial aspects, such as ground-based network entities (e.g., BSs 102) , and non-terrestrial aspects, such as satellite 140 and aircraft 145, which may include network entities on-board (e.g., one or more BSs) capable of communicating with other network elements (e.g., terrestrial BSs) and UEs.

In the depicted example, wireless communications network 100 includes BSs 102, UEs 104, and one or more core networks, such as an Evolved Packet Core (EPC) 160 and 5G Core (5GC) network 190, which interoperate to provide communications services over various communications links, including wired and wireless links.

FIG. 1 depicts various example UEs 104, which may more generally include: a cellular phone, smart phone, session initiation protocol (SIP) phone, laptop, personal digital assistant (PDA) , satellite radio, global positioning system, multimedia device, video device, digital audio player, camera, game console, tablet, smart device, wearable device, vehicle, electric meter, gas pump, large or small kitchen appliance, healthcare device, implant, sensor/actuator, display, intemet of things (IoT) devices, always on (AON) devices, edge processing devices, or other similar devices. UEs 104 may also be referred to more generally as a mobile device, a wireless device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

BSs 102 wirelessly communicate with (e.g., transmit signals to or receive signals from) UEs 104 via communications links 120. The communications links 120 between BSs 102 and UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a BS 102 and/or downlink (DL) (also referred to as forward link) transmissions from a BS 102 to a UE 104. The communications links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity in various aspects.

BSs 102 may generally include: a NodeB, enhanced NodeB (eNB) , next generation enhanced NodeB (ng-eNB) , next generation NodeB (gNB or gNodeB) , access point, base transceiver station, radio base station, radio transceiver, transceiver function, transmission reception point, and/or others. Each of BSs 102 may provide communications coverage for a respective coverage area 110, which may sometimes be referred to as a cell, and which may overlap in some cases (e.g., small cell 102' may have a coverage area 110'that overlaps the coverage area 110 of a macro cell) . A BS may, for example, provide communications coverage for a macro cell (covering relatively large geographic area) , a pico cell (covering relatively smaller geographic area, such as a sports stadium) , a femto cell (relatively smaller geographic area (e.g., a home) ) , and/or other types of cells.

Generally, a cell may refer to a portion, partition, or segment of wireless communication coverage served by a network entity within a wireless communication network. A cell may have geographic characteristics, such as a geographic coverage area, as well as radio frequency characteristics, such as time and/or frequency resources dedicated to the cell. For example, a specific geographic coverage area may be covered by multiple cells employing different frequency resources (e.g., bandwidth parts) and/or different time resources. As another example, a specific geographic coverage area may be covered by a single cell.

While BSs 102 are depicted in various aspects as unitary communications devices, BSs 102 may be implemented in various configurations. For example, one or more components of a base station may be disaggregated, including a central unit (CU) , one or more distributed units (DUs) , one or more radio units (RUs) , a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) , or a Non-Real Time (Non-RT) RIC, to name a few examples. In another example, various aspects of a base station may be virtualized. More generally, a base station (e.g., BS 102) may include components that are located at a single physical location or components located at various physical locations. In examples in which a base station includes components that are located at various physical locations, the various components may each perform functions such that, collectively, the various components achieve functionality that is similar to a base station that is located at a single physical location. In some aspects, a base station including components that are located at various physical locations may be referred to as a disaggregated radio access network architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. FIG. 2 depicts and describes an example disaggregated base station architecture.

Different BSs 102 within wireless communications network 100 may also be configured to support different radio access technologies, such as 3G, 4G, and/or 5G. For example, BSs 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., an S1 interface) . BSs 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through second backhaul links 184. BSs 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over third backhaul links 134 (e.g., X2 interface) , which may be wired or wireless.

Wireless communications network 100 may subdivide the electromagnetic spectrum into various classes, bands, channels, or other features. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, or a subband. For example, 3GPP currently defines Frequency Range 1 (FR1) as including 410 MHz -7125 MHz, which is often referred to (interchangeably) as “Sub-6 GHz” . Similarly, 3GPP currently defines Frequency Range 2 (FR2) as including 24,250 MHz -52,600 MHz, which is sometimes referred to (interchangeably) as a “millimeter wave” ( “mmW” or “mmWave” ) . A base station configured to communicate using mmWave/near mmWave radio frequency bands (e.g., a mmWave base station such as BS 180) may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

The communications links 120 between BSs 102 and, for example, UEs 104, may be through one or more carriers, which may have different bandwidths (e.g., 5, 10, 15, 20, 100, 400, and/or other MHz) , and which may be aggregated in various aspects. Carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) .

Communications using higher frequency bands may have higher path loss and a shorter range compared to lower frequency communications. Accordingly, certain base stations (e.g., 180 in FIG. 1) may utilize beamforming 182 with a UE 104 to improve path loss and range. For example, BS 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming. In some cases, BS 180 may transmit a beamformed signal to UE 104 in one or more transmit directions 182'. UE 104 may receive the beamformed signal from the BS 180 in one or more receive directions 182” . UE 104 may also transmit a beamformed signal to the BS 180 in one or more transmit directions 182” . BS 180 may also receive the beamformed signal from UE 104 in one or more receive directions 182'. BS 180 and UE 104 may then perform beam training to determine the best receive and transmit directions for each of BS 180 and UE 104. Notably, the transmit and receive directions for BS 180 may or may not be the same. Similarly, the transmit and receive directions for UE 104 may or may not be the same.

Wireless communications network 100 further includes a Wi-Fi AP 150 in communication with Wi-Fi stations (STAs) 152 via communications links 154 in, for example, a 2.4 GHz and/or 5 GHz unlicensed frequency spectrum.

Certain UEs 104 may communicate with each other using device-to-device (D2D) communications link 158. D2D communications link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , a physical sidelink control channel (PSCCH) , and/or a physical sidelink feedback channel (PSFCH) .

EPC 160 may include various functional components, including: a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and/or a Packet Data Network (PDN) Gateway 172, such as in the depicted example. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, MME 162 provides bearer and connection management.

Generally, user Intemet protocol (IP) packets are transferred through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation as well as other functions. PDN Gateway 172 and the BM-SC 170 are connected to IP Services 176, which may include, for example, the Intemet, an intranet, an IP Multimedia Subsystem (IMS) , a Packet Switched (PS) streaming service, and/or other IP services.

BM-SC 170 may provide functions for MBMS user service provisioning and delivery. BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and/or may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to the BSs 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and/or may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

5GC 190 may include various functional components, including: an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. AMF 192 may be in communication with Unified Data Management (UDM) 196.

AMF 192 is a control node that processes signaling between UEs 104 and 5GC 190. AMF 192 provides, for example, quality of service (QoS) flow and session management.

Intemet protocol (IP) packets are transferred through UPF 195, which is connected to the IP Services 197, and which provides UE IP address allocation as well as other functions for 5GC 190. IP Services 197 may include, for example, the Intemet, an intranet, an IMS, a PS streaming service, and/or other IP services.

In various aspects, a network entity or network node can be implemented as an aggregated base station, as a disaggregated base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

FIG. 2 depicts an example disaggregated base station (BS) 200 architecture. The disaggregated BS 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both) . A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an Fl interface. The DUs 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 240.

Each of the units, e.g., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communications interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally or alternatively, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (e.g., Central Unit -User Plane (CU-UP) ) , control plane functionality (e.g., Central Unit -Control Plane (CU-CP) ) , or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E 1 interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3^rd Generation Partnership Project (3GPP) . In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210.

Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU (s) 240 can be implemented to handle over the air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU (s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU (s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface) . For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) . Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an O1 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more RUs 240 via an O1 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .

FIG. 3 depicts aspects of an example BS 102 and a UE 104.

Generally, BS 102 includes various processors (e.g., 320, 330, 338, and 340) , antennas 334a-t (collectively 334) , transceivers 332a-t (collectively 332) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339) . For example, BS 102 may send and receive data between BS 102 and UE 104. BS 102 includes controller/processor 340, which may be configured to implement various functions described herein related to wireless communications.

Generally, UE 104 includes various processors (e.g., 358, 364, 366, and 380) , antennas 352a-r (collectively 352) , transceivers 354a-r (collectively 354) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., retrieved from data source 362) and wireless reception of data (e.g., provided to data sink 360) . UE 104 includes controller/processor 380, which may be configured to implement various functions described herein related to wireless communications.

In regards to an example downlink transmission, BS 102 includes a transmit processor 320 that may receive data from a data source 312 and control information from a controller/processor 340. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , and/or others. The data may be for the physical downlink shared channel (PDSCH) , in some examples.

Transmit processor 320 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 320 may also generate reference symbols, such as for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , PBCH demodulation reference signal (DMRS) , and channel state information reference signal (CSI-RS) .

Transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) in transceivers 332a-332t. Each modulator in transceivers 332a-332t may process a respective output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from the modulators in transceivers 332a-332t may be transmitted via the antennas 334a-334t, respectively.

In order to receive the downlink transmission, UE 104 includes antennas 352a-352r that may receive the downlink signals from the BS 102 and may provide received signals to the demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples to obtain received symbols.

RX MIMO detector 356 may obtain received symbols from all the demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 104 to a data sink 360, and provide decoded control information to a controller/processor 380.

In regards to an example uplink transmission, UE 104 further includes a transmit processor 364 that may receive and process data (e.g., for the PUSCH) from a data source 362 and control information (e.g., for the physical uplink control channel (PUCCH) ) from the controller/processor 380. Transmit processor 364 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)) . The symbols from the transmit processor 364 may be precoded by a TX MIMO processor 366 if applicable, further processed by the modulators in transceivers 354a-354r (e.g., for SC-FDM) , and transmitted to BS 102.

At BS 102, the uplink signals from UE 104 may be received by antennas 334a-t, processed by the demodulators in transceivers 332a-332t, detected by a RX MIMO detector 336 if applicable, and further processed by a receive processor 338 to obtain decoded data and control information sent by UE 104. Receive processor 338 may provide the decoded data to a data sink 339 and the decoded control information to the controller/processor 340.

Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

Scheduler 344 may schedule UEs for data transmission on the downlink and/or uplink.

In various aspects, BS 102 may be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 312, scheduler 344, memory 342, transmit processor 320, controller/processor 340, TX MIMO processor 330, transceivers 332a-t, antenna 334a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 334a-t, transceivers 332a-t, RX MIMO detector 336, controller/processor 340, receive processor 338, scheduler 344, memory 342, and/or other aspects described herein.

In various aspects, UE 104 may likewise be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 362, memory 382, transmit processor 364, controller/processor 380, TX MIMO processor 366, transceivers 354a-t, antenna 352a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 352a-t, transceivers 354a-t, RX MIMO detector 356, controller/processor 380, receive processor 358, memory 382, and/or other aspects described herein.

In some aspects, a processor may be configured to perform various operations, such as those associated with the methods described herein, and transmit (output) to or receive (obtain) data from another interface that is configured to transmit or receive, respectively, the data.

FIGS. 4A, 4B, 4C, and 4D depict aspects of data structures for a wireless communications network, such as wireless communications network 100 of FIG. 1.

In particular, FIG. 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, FIG. 4B is a diagram 430 illustrating an example of DL channels within a 5G subframe, FIG. 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and FIG. 4D is a diagram 480 illustrating an example of UL channels within a 5G subframe.

Wireless communications systems may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. Such systems may also support half-duplex operation using time division duplexing (TDD) . OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth (e.g., as depicted in FIGS. 4B and 4D) into multiple orthogonal subcarriers. Each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and/or in the time domain with SC-FDM.

A wireless communications frame structure may be frequency division duplex (FDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for either DL or UL. Wireless communications frame structures may also be time division duplex (TDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for both DL and UL.

In FIG. 4A and 4C, the wireless communications frame structure is TDD where D is DL, U is UL, and X is flexible for use between DL/UL. UEs may be configured with a slot format through a received slot format indicator (SFI) (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) . In the depicted examples, a 10 ms frame is divided into 10 equally sized 1 ms subframes. Each subframe may include one or more time slots. In some examples, each slot may include 7 or 14 symbols, depending on the slot format. Subframes may also include mini-slots, which generally have fewer symbols than an entire slot. Other wireless communications technologies may have a different frame structure and/or different channels.

In certain aspects, the number of slots within a subframe is based on a slot configuration and a numerology. For example, for slot configuration 0, different numerologies (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2^μ × 15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ = 0 has a subcarrier spacing of 15 kHz and the numerology μ = 5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGS. 4A, 4B, 4C, and 4D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ = 2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

As depicted in FIGS. 4A, 4B, 4C, and 4D, a resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends, for example, 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 4A, some of the REs carry reference (pilot) signals (RS) for a UE (e.g., UE 104 of FIGS. 1 and 3) . The RS may include demodulation RS (DMRS) and/or channel state information reference signals (CSI-RS) for channel estimation at the UE.The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and/or phase tracking RS (PT-RS) .

FIG. 4B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including, for example, nine RE groups (REGs) , each REG including, for example, four consecutive REs in an OFDM symbol.

A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE (e.g., 104 of FIGS. 1 and 3) to determine subframe/symbol timing and a physical layer identity.

A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing.

Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DMRS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and/or paging messages.

As illustrated in FIG. 4C, some of the REs carry DMRS (indicated as R for one particular configuration, but other DMRS configurations are possible) for channel estimation at the base station. The UE may transmit DMRS for the PUCCH and DMRS for the PUSCH. The PUSCH DMRS may be transmitted, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. UE 104 may transmit sounding reference signals (SRS) . The SRS may be transmitted, for example, in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 4D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI. UCI.

Aspects Related to Beam Management

FIG. 5 is a diagram depicting example radio resource control (RRC) connection establishment and beam management 500. As shown, at 502, a user equipment (UE) may initially be in an RRC idle state (or an RRC inactivate state) . An RRC idle state refers to a state of a UE where the UE is switched on but does not have any established RRC connection. The RRC idle state allows the UE to reduce battery power consumption, for example, relative to an RRC connected state. In an RRC connected state, the UE is connected to the network and radio resources are allocated to the UE.

In order to perform data transfer and/or make/receive calls, the UE needs to establish connection with a network using an initial access procedure, at 504. The initial access procedure is a sequence of processes performed between the UE and the network to establish the RRC connection. The UE may be in an RRC connected state subsequent to establishing the connection.

The UE may perform beam management after entering an RRC connected state. Beam management includes a set of operations used to establish and retain a (e.g., optimal) beam pair that can be used for downlink and uplink transmission/reception. A beam pair includes a transmit beam and a corresponding receive beam in one link direction. The beam management may include conventional P1, P2, and/or P3 beam management procedures, illustrated below in FIG. 6.

Beam management procedures may further include, at 508 and 510, beam failure detection and recovery operations. For example, a UE may detect a beam failure when layer 1 (L1) reference signal received power (RSRP) for a connected beam falls below a certain limit. After beam failure is detected, the UE identifies a candidate beam suitable for communication and performs beam failure recovery (BFR) . If the BFR is not successful, the UE may declare a radio link failure (RLF) , at 512.

FIG. 6 is a diagram illustrating examples 600, 610, and 620 of beam management procedures. As shown in FIG. 6, examples 600, 610, and 620 include a UE 104 in communication with a BS 102 in a wireless network (e.g., wireless communications network 100 in FIG. 1) . However, the devices shown in FIG. 6 are provided as examples, and the wireless network may support communication and beam management between other devices (e.g., between a UE 104 and a network entity, a UE 104 and a transmission reception point (TRP) , between a mobile termination node and a control node, between an integrated access and backhaul (IAB) child node and an IAB parent node, between a scheduled node and a scheduling node, and/or the like) . In some aspects, the UE 104 and the BS 102 are in a connected state (e.g., RRC connected state and/or the like) .

BS 102 and UE 104 may communicate to perform beam management using reference signals (RSs) (e.g., synchronization signal blocks (SSBs) , demodulation reference signals (DM-RSs) , channel state information reference signals (CSI-RSs) , etc. ) .

Example 600 depicts a first beam management procedure (e.g., such as a P1 CSI-RS beam management procedure) . The first beam management procedure may be referred to as a beam selection procedure, an initial beam acquisition procedure, a beam sweeping procedure, a cell search procedure, a beam search procedure, and/or the like. In example 600, reference signals are configured to be transmitted from the BS 102 to UE 104. The reference signals may be configured to be periodic (e.g., using RRC signaling) , semi-persistent (e.g., using media access control (MAC) control element (MAC-CE) signaling) , and/or aperiodic (e.g., using downlink control information (DCI)) .

As illustrated, the first beam management procedure may include BS 102 performing beam sweeping over multiple transmit (TX) beams 602 (1) -602 (9) (individually referred to as “transmit beam 602” and collectively referred to as “transmit beams 602” ) . A transmit beam, such as transmit beam 602, is a beam, or transmission configuration indicator (TCI) state, that is used by a wireless communication device (e.g., a BS 102 and/or UE 104) for transmitting signals. For example, BS 102 may transmit a reference signal using each transmit beam 602 associated with BS 102 for beam management.

To enable UE 104 to perform receive (RX) beam sweeping (e.g., a receive beam may be a beam, a TCI state, and/or spatial relation information that is used by a wireless communication device for receiving signals) , BS 102 uses a transmit beam 602 to transmit (e.g., with repetitions) each reference signal at multiple times within a same resource set to enable UE 104 to sweep through receive beams 604 (1) -604 (9) (individually referred to as “receive beam 604” and collectively referred to as “receive beams 604” ) in multiple transmission instances. For example, if BS 102 has a set of N transmit beams 602 (e.g., in this example, N is equal to nine) and UE 104 has a set of M receive beams 604 (e.g., in this example, M is equal to nine) , then the reference signal may be transmitted on each of the N transmit beams 602 M times such that UE 104 receives Minstances of the reference signals per transmit beam 602. As a result, the first beam management procedure helps to enable UE 104 to measure a reference signal on different transmit beams 602, using different receive beams 604, to support the selection of BS 102 transmit beams 602/UE 104 receive beam (s) 604 beam pair (s) . UE 104 may report the measurements to BS 102 to enable BS 102 to select one or more beam pair (s) for communication between BS 102 and UE 104.

Example 610, illustrated in FIG. 6, depicts a second beam management procedure (e.g., such as a P2 CSI-RS beam management procedure) . The second beam management procedure may be referred to as a beam refinement procedure, a BS beam refinement procedure, a TRP beam refinement procedure, a transmit beam refinement procedure, and/or the like.

As illustrated, the second beam management procedure includes BS 102 performing beam sweeping over one or more transmit beams 602 (e.g., transmit beams 602 (2) -602 (8) ) . The one or more transmit beams 602 (e.g., transmit beams 602 (2) -602 (8)) may be a subset of all transmit beams 602 associated with BS 102 (e.g., determined based, at least in part, on measurements reported by UE 104 in connection with the first beam management procedure) . BS 102 transmits a reference signal using each transmit beam 602 (2) -602 (8) for beam management. UE 104 measures each reference signal using a single (e.g., a same) receive beam 604 (e.g., determined based, at least in part, on measurements performed in connection with the first beam management procedure) . For example, UE 104 measures each reference signal using receive beam 604 (5) . As such, the second beam management procedure may enable BS 102 to select a best transmit beam 602 (e.g., from transmit beams 602 (2) -602 (8) ) based on measurements of the reference signals (e.g., measured by UE 104 using the single receive beam 604 (5)) reported by UE 104. For example, the second beam management procedure may enable BS 102 to select a best transmit beam 602 as transmit beam 602 (5) .

Example 620, illustrated in FIG. 6, depicts a third beam management procedure (e.g., such as a P3 CSI-RS beam management procedure) . The third beam management procedure may be referred to as a beam refinement procedure, a UE beam refinement procedure, a receive beam refinement procedure, and/or the like.

As illustrated, the third beam management procedure includes BS 102 transmitting one or more reference signals using a single transmit beam 604 (e.g., determined based, at least in part, on measurements reported by UE 104 in connection with the first beam management procedure and/or the second beam management procedure) . For example, BS 102 transmits one or more reference signals using transmit beam 602 (5) . To enable UE 104 to perform receive beam sweeping, BS 102 may use transmit beam 602 (5) to transmit (e.g., with repetitions) reference signals at multiple times within a same resource set such that UE 104 can sweep through one or more receive beams 604 (e.g., receive beams 604 (2) -604 (8) ) in multiple transmission instances. The one or more receive beams 604 (e.g., receive beams 604 (2) -604 (8) ) may be a subset of all receive beams 604 associated with UE 104 (e.g., determined based on measurements performed in connection with the first beam management procedure and/or the second beam management procedure) . The third beam management procedure helps to enable BS 102 and/or UE 104 to select a best receive beam 604 (e.g., from receive beams 604 (2) -604 (8) ) based on reported measurements received from UE 104 (e.g., of the reference signal of the transmit beam 602 (5) using the one or more receive beams 604 (2) -604 (8)) . For example, the third beam management procedure may enable UE 104 to select a best receive beam 604 as receive beam 604 (5) .

FIG. 6 is provided as an example of beam management procedures for determining a beam pair with good connectivity for communication. Other examples of beam management procedures that differ from what is described with respect to FIG. 6, however, may be considered when determining beam pairs for wireless communication.

As illustrated in FIG. 6, conventional methods for beam selection, also referred to as an exhaustive search, searches each beam, one by one, for a combination between a transmitter and a receiver that will result in a maximum value of a given criterion, such as transmitter/receiver channel gain. Although the exhaustive search method helps to select a suitable transmission/reception beam pair, this method may become impractical due to (1) the exponentially increasing search time as a number of beams and/or radiation patterns increases and/or (2) ultra-low latency requirements (e.g., requirements to process a very high volume of data packets with an extraordinarily low tolerance for delay) , for example, which is forecasted to be around 1-10μs for 6G technology.

Aspects Related to ML-Aided Beam Management Procedures

Artificial intelligence (AI) , and more specifically, machine learning (ML) techniques have been introduced to help overcome the technical problems associated with conventional beam management procedures, such as those present in 5G, 5G-Advanced, and 6G networks. ML, a subdivision of AI, refers to training computer algorithms to make predictions based on experience. ML is an efficient tool that may be used to help reduce the complexity involved in generating beams and the overhead associated with beam management without sacrificing system performance. For example, with the help of ML techniques, beam selection may be performed in a fraction of the time taken by conventional exhaustive search methods and with performance comparable to that of such methods.

FIG. 7 is a diagram illustrating an example architecture 700 of a functional framework for radio access network (RAN) intelligence enabled by data collection. As illustrated, architecture 700 includes multiple logical entities, such as a model training host 702, a model inference host 704, data sources 706, and an actor 708. RAN intelligence enabled by ML and the associated functional framework may be utilized in various use cases, such as beam management, energy saving, load balancing, mobility management, and/or coverage optimization, among other examples. One or more benefits may be realized through the use of ML enabled RAN in such use cases.

Model inference host 704, in architecture 700, is configured to run an ML model based on inference data 712 provided by data sources 706. Model inference host 704 may produce an output 714 (e.g., a prediction) based on inference data 712, that is then provided as input into actor 708.

Actor 708 may be an element or an entity of a core network (CN) or a RAN. For example, actor 708 may be a UE (e.g., UE 104 in FIG. 1) , a BS (e.g., a BS 102 in FIG. 1) or another network node (e.g., a gNB, a centralized unit (CU) , a distributed unit (DU) , and/or a radio unit (RU) ) , among other examples. Additionally, the type of actor 708 may also depend on the type of tasks performed by model inference host 704, the type of inference data 712 provided to model inference host 704, and/or the type of output 714 produced by model inference host 704.

For example, if output 714 from model inference host 704 is associated with beam management (e.g., produced from ML model (s) described in more detail below with respect to FIG. 7) , actor 708 may be a UE, a DU, or an RU. As another example, if output 714 from model inference host 704 is associated with transmission and/or reception scheduling, actor 708 may be a CU or a DU.

After actor 708 receives output 714 from model inference host 704, actor 708 may determine whether to act based on the output. For example, if actor 708 is a DU or an RU and the output from model inference host 704 is associated with beam management, actor 708 may determine whether to change/modify a transmission and/or a reception beam based on output 714. If actor 708 determines to act based on output 714, actor 708 may indicate the action to at least one subject of action 710. For example, if actor 708 determines to change/modify a transmission and/or reception beam for a communication between actor 708 and the subject of action 710 (e.g., a UE) , then actor 708 may transmit a beam (re-) configuration or a beam switching indication to subject of action 710. Actor 708 may modify its transmission and/or reception beam based on the beam (re-) configuration, such as switching to a new transmission and/or reception beam and/or applying different parameters for a transmission and/or reception beam, among other examples. As another example, actor 708 may be a UE, and output 714 from model inference host 704 may be associated with beam management. For example, output 714 may be one or more predicted measurement values for one or more beams. Actor 708, the UE, may determine that a measurement report (e.g., an L1 RSRP report) is to be transmitted to a BS in communication with the UE. In some cases, actor 708 and subject of action 710 are the same entity.

Data sources 706 may be configured for collecting data that is used as training data 716 for training an ML model, or as inference data 712 for feeding an ML model inference operation. In particular, data sources 706 may collect data from one or more CN and/or RAN entities, which may include subject of action 710, and provide the collected data to a model training host 702 for ML model training. For example, after a subject of action 710 (e.g., a UE) receives a beam configuration from actor 708, subject of action 710 may provide performance feedback associated with the beam configuration to data sources 706, where the performance feedback may be used by the model training host 702 for monitoring and/or evaluating the ML model performance, such as whether output 714, provided to actor 708, is accurate. In some examples, if output 714 provided to actor 708 is inaccurate (or the accuracy is below an accuracy threshold) , then model training host 702 may determine to modify or retrain the ML model used by model inference host 704, such as via an ML model deployment/update.

In some aspects, an ML model is deployed at or on a network entity (e.g., such as BS 102 in FIG. 1) for purposes of spatial domain (SD) , temporal domain (TD) , and/or frequency domain (FD) beam prediction. More specifically, a model interference host, such as model inference host 704 in FIG. 7, may be deployed at or on the network entity for such beam prediction. The TD refers to the analytic space in which signals are conveyed in terms of time, rather than frequency. The FD refers to the analytic space in which signals are conveyed in terms of frequency, rather than time. For example, the network entity may be configured to predict downlink receive (RX) beams that are to be used by a UE for receiving downlink transmission (s) from the network entity. To enable such prediction, the UE may be required to feed back its receive beam information (e.g., beam shapes, direction, beamforming, gains, and/or the like) to the network entity.

In some other aspects, an ML model is deployed at or on a UE (e.g., such as UE 104 in FIG. 1) for purposes of SD, TD, and/or FD beam prediction. More specifically, a model inference host, such as model inference host 704 in FIG. 7, may be deployed at or on the UE for such beam prediction. A scenario where the ML model, at or on the UE, is configured to predict SD beams may be referred to as a beam management case 1, or simply “BM-Casel . ” Additionally, a scenario where the ML model, at or on the UE, is configured to predict TD beams may be referred to as a beam management case 2, or simply “BM-Case2. ” SD communication resource prediction (also referred to as beam prediction) may refer to predicting a measurement for a first communication resource associated with a first beam (e.g., a first transmit beam of a network entity) based on a measurement of a second communication resource associated with a second beam (e.g., a second transmit beam of the network entity) , wherein the first communication resource and the second communication resource correspond to a same time and frequency resource. FD communication resource prediction (also referred to as beam prediction) may refer to predicting a measurement for a first communication resource associated with a first beam (e.g., a first transmit beam of a network entity) based on a measurement of a second communication resource associated with the first beam, wherein the first communication resource and the second communication resource correspond to a same time resource but a different frequency resource. TD communication resource prediction (also referred to as beam prediction) may refer to predicting a measurement for a first communication resource associated with a first beam (e.g., a first transmit beam of a network entity) based on a measurement of a second communication resource associated with the first beam, wherein the first communication resource and the second communication resource correspond to a same frequency resource but a different time resource.

FIG. 8A is a diagram illustrating example beam prediction 800a by a UE 104. In FIG. 8A, an ML model 810 is deployed at or on UE 104 to enable UE 104 to make one or more beam predictions based on data input to ML model 810.

For example, a BS (e.g., BS 102 in FIGS. 1 and 3) may transmit one or more signals, via a first set of beams 804, in a first set of communication resources (e.g., channel measurement resources) . UE 104 may perform measurements (e.g., L1 RSRP measurements and/or other measurements) of the one or more signals transmitted in the first set of communication resources, or a subset thereof, to obtain a first set of measurements 812 (sometimes referred to as parameters or channel characteristics) . For example, each beam (or else a subset thereof) 804, from the first set of beams carrying the one or more signals, may be associated with one or more measurements 812 performed by UE 104. UE 104 may input the first set of measurements 812 (e.g., L1 RSRP measurement values) into ML model 810 along with information associated with the first set of beams and/or first set of communication resources (or a subset thereof) . The information associated with the first set of beams may include a beam direction (e.g., a spatial direction) , beam width, beam shape, and/or other characteristics of the respective beam.

ML model 810 may be configured to output one or more predictions. More specifically, ML model 810 may be configured to predict one or more measurement values 814 for a second set of communication resources (e.g., channel prediction resources) associated with a second set of beams 808. The one or more measurement values 814 may include predicted channel characteristics (e.g., predicted L1 RSRP measurement values) associated with the second set of communication resources, where the second set of communication resources are associated with the second set of beams 808.

In some examples, the first set of beams 804 (e.g., that are measured) may be referred to as “Set B beams” and the second set of beams 808 (e.g., that are associated with predicted measurements for the second set of communication resources) may be referred to as “Set A beams. ” Put another way, the “Set B beams” are a set of beams for which measurements are taken and used as inputs in ML model 810, while the “Set A beams” are a set of beams for which ML model 810 performs predictions.

In some examples, first set of beams 804 are a subset of second set of beams 808. In some other examples, first set of beams 804 and second set of beams 808 are different beams and/or may be mutually exclusive sets. For example, first set of beams 804 may include wide beams (e.g., unrefined beams or beams having a beam width that satisfies a first threshold) , and second set of beams 808 may include narrow beams (e.g., refined beams or beams having a beam width that satisfies a second threshold) .

Use of ML model 810 for beam prediction may reduce a quantity of beam measurements that are performed by UE 104 (e.g., compared to exhaustive search methods described above with respect to FIG. 6) , thereby conserving power at UE 104 and/or network resources that would have otherwise been used to measure all beams included in at least the first set of beams.

In some aspects, this type of prediction may be referred to as a codebook-based SD selection or prediction. The codebook-based SD prediction/selection may be associated with an initial access, a secondary cell group (SCG) setup, a serving beam refinement, and/or a link quality (e.g., channel quality indicator (CQI) or precoding matrix indicator (PMI) ) and interference adaptation.

As another example, an output of ML model 810 may include a point-direction, an angle of departure (AoD) , and/or an angle of arrival (AoA) of a beam included in the second set of beams (e.g., the “Set A beams” ) . This type of prediction may be referred to as a non-codebook-based SD selection or prediction. The non-codebook-based prediction/selection may be associated with a serving beam refinement, and/or a link quality (e.g., CQI or PMI) and interference adaptation. As another example, multiple measurement reports and/or values, collected at different points in time, may be input to ML model 810. This may enable ML model 810 to output codebook-based and/or non-codebook-based predictions for a measurement value, an AoD, and/or an AoA, among other examples, of a beam at a future time. The output (s) of ML model 810, may facilitate initial access procedures, secondary cell group (SCG) setup procedures, beam refinement procedures (e.g., a P2 beam management procedure and/or a P3 beam management procedure as described above with respect to FIG. 6) , link quality or interference adaptation procedures, beam failure and/or beam blockage predictions, and/or radio link failure predictions, among other examples.

In some aspects, an output of ML model 810 may include a temporal beam prediction. The TD beam prediction may be associated with a serving beam refinement, a link quality (e.g., CQI or PMI) and interference adaptation, a beam failure/blockage prediction, and/or a radio link failure (RLF) prediction. For example, the ML model 810 may predict channel characteristics for a given beam and a given frequency for a future time based on a measurement of a signal communicated on the given beam and the given frequency.

In some aspects, ML model 810 performs SD downlink beam predictions for beams included in the “Set A beams” based on measurement results of beams included in the “Set B beams. ” In some aspects, ML model 810 performs TD downlink beam prediction for beams included in the “Set A beams” based on historic measurement results of beams included in the “Set B beams. ”

Aspects Related to the Prediction of Communication Resources

In some aspects, an ML model may be used to predict communication resources, such to assist in determining a set of beams (e.g., uplink receive beams, uplink transmit beams, downlink receive beams, and/or downlink transmit beams) to be used for communication. Receive beams correspond to spatial beams configured at an apparatus, such as a network entity (e.g., such as BS 102 in FIGs. 1 and 3) or UE, for receiving signals. For example, each receive beam of a set of receive beams corresponds to one or more of a corresponding amplitude weighting pattern to apply to signals received over each of a plurality of antennas of the apparatus or a corresponding phase shift pattern to apply to signals received over each of the plurality of antennas of the apparatus. Transmit beams correspond to spatial beams configured at an apparatus, such as a network entity (e.g., such as BS 102 in FIGs. 1 and 3) or UE, for transmitting signals. For example, each transmit beam of a set of transmit beams corresponds to one or more of a corresponding amplitude weighting pattern to apply to signals transmitted over each of a plurality of antennas of the apparatus or a corresponding phase shift pattern to apply to signals transmitted over each of the plurality of antennas of the apparatus. A “set” as discussed herein may include one or more elements. Accordingly, a set of beams includes one or more beams.

An ML model may be configured to predict communication resources associated with a set of beams (e.g., referred to as “Set A beams, ” which may correspond to transmit beams, such as downlink transmit beams) based on measuring one or more signals (e.g., associated with another set of beams, referred to as “Set B beams, ” which may correspond to transmit beams, such as downlink transmit beams) communicated in another set of communication resources. Identifiers of the predicted communication resources may be sent to the network entity. The network entity may use such identifiers to determine a set of uplink receive beams associated with the network entity that are to be used for subsequent uplink communication and/or a set of downlink transmit beams to be used for subsequent downlink communication.

For example, FIG. 8B is a diagram illustrating example communication resource prediction 800b by a UE 104 based on measurement of a signal from a network entity 802 (e.g., such as BS 102 in FIGs. 1 and 3) . In FIG. 8B, an ML model 810 is deployed at or on UE 104 to enable UE 104 to make one or more communication resource predictions based on data input to ML model 810. Though embodiments herein describe the use of an ML model to predict communication resources associated with a set of beams, in certain other embodiments, other prediction techniques (e.g., defined in a specification, such as 3GPP) may be used to predict the communication resources. Further, the prediction may occur somewhere else than UE 104, such as where UE 104 sends measurement information to another device to perform prediction, where the ML model is deployed at the other device.

In certain aspects, predicting communication resources to assist in determining a set of beams to be used for communication may be referred to as predicting beams.

To perform communication resource prediction, network entity 802 may first transmit one or more signals, via a first set of beams 824, in a first set of communication resources 822. Network entity 802 may be any network entity, such as BS 102 in FIGS. 1 and 3. The first set of beams 824 may be a first set of downlink transmit beams of the network entity 802. UE 104 may measure the one or more signals transmitted in the first set of communication resources 822, to obtain a first set of measurements (sometimes referred to as parameters or channel characteristics) .

For example, each signal carried via each beam in the first set of beams 824 may be associated with one or more measurements performed by UE 104. UE 104 may input the first set of measurements into ML model 810. In some aspects, information associated with the first set of beams 824 (e.g., beam direction, beam width, beam shape, and/or other characteristics) is also input into ML model 810 for communication resource prediction.

ML model 810 is configured to output one or more predictions, and more specifically, is configured to predict communication resources. As used herein, predicting communication resources comprises predicting one or more parameters associated with the communication resources. For example, based on the one or more measurements provided as input into ML model 810, ML model 810 predicts one or more parameters (e.g., measurement values and/or channel characteristics) for a second set of communication resources 826 associated with a second set of beams 828. In certain aspects, the second set of beams 828 corresponds to a second set of downlink transmit beams of the network entity 802. For example, the ML model 810 predicts what measurement (s) of one or more signals would be if they were transmitted by network entity 802 on the second set of communication resources 826 using the second set of beams 828. In certain aspects, the second set of beams 828 corresponds to a set of uplink receive beams of network entity 802. For example, the ML model 810 predicts measurement (s) of one or more signals if they had been transmitted by network entity 802 on transmit beams that have the same spatial configuration as the set of uplink receive beams.

In some aspects, UE 104 sends one or more identifiers of the second set of communication resources 826 to network entity 802. Network entity 802 may determine a set ofuplink receive beams to use for receiving subsequent uplink transmission (s) from UE 104 based on the second set of communication resources 826. For example, network entity 802 may store or have access to information, such as a mapping, that associates/maps the second set of communication resources 826 with the set of uplink receive beams. In certain aspects, UE 104 may not have information regarding the association of the set of uplink receive beams with the second set of communication resources 826.

Using ML models for predicting communication resources, to assist in determining a set of beams that may be used for subsequent communication, helps to overcome technical problems associated with conventional beam selection procedures, such as those described above with respect to FIG. 6.

Aspects Related to Lower-Layer Triggered Mobility (LTM)

Handover is a process of transferring an ongoing communication session of a UE (e.g., such as UE 104 in FIGS. 1-3) from a source cell to a target cell while in a connected state. The target cell may belong to either a same network entity as the source cell (e.g., intra-network entity (e.g., intra-gNB) handover) or a different network entity than the network entity associated with the source cell (e.g., inter-network entity (e.g., inter-gNB) handover) . One of the motivations behind handover procedures is to assist in the seamless connectivity and continuity of service for the UE, especially while the UE is mobile.

New Radio (NR) supports different types of handover, including handover procedures where the network controls UE mobility based on UE measurement reporting. In this procedure, a source network entity (e.g., gNB) associated with a source cell of a UE, triggers a handover for the UE by transmitting a handover request to a target network entity associated with a target cell (e.g., inter-gNB handover) . After receiving an acknowledgement (ACK) from the target network entity, the source network entity initiates the handover of the UE from the source cell to the target cell (e.g., from the source network entity to the target network entity) by transmitting a handover command with target cell configuration. The UE then accesses the target cell after the target cell configuration is applied.

Handover procedures supported in 3GPP, through Release 17, involve cell changes/switching triggered by layer 3 (L3) measurements and carried out via radio resource control (RRC) signaling. Each procedure requires the reconfiguration of upper layers of the protocol stack (e.g., the RRC layer and/or the packet data convergence protocol (PDCP) layer) and/or the resetting of lower layers of the protocol stack (e.g., the medium access control (MAC) layer and/or the physical (PHY) layer) , which may result in increased latency, large overhead, and/or long interruption times.

Accordingly to overcome such problems with existing handover procedures, in 3GPP Release 18, a new layer 1 (L1) /layer 2 (L2) -based handover procedure, also referred to as “Lower Layer Triggered Mobility (LTM) , ” was introduced. LTM enables a handover via L1/L2 signaling. As such, any re-configuration of the upper layers may be avoided, while also minimizing changes to the configuration of the lower years of the protocol stack. The LTM supports both intra-distributed unit (DU) mobility and intra-central unit (CU) -inter-DU mobility (e.g., where the source DU and target DU are connected to a common CU) .

FIG. 9 depicts the procedure 900 for LTM. As illustrated, procedure 900 includes steps 906-930, which are broken into three categories: (1) LTM preparation and initiation, (2) synchronization, and (3) beam management/refinement. Procedure 900 begins, at step 906, by a UE 904 (e.g., such as UE 104 in FIGS. 1-3) transmitting a measurement report message to a network entity 902 (e.g., such as BS 102 in FIGS. 1 and 3) . In response to receiving the measurement report message at 906, network entity 902 determines to use LTM and accordingly initiate LTM candidate preparation, at step 908, by compiling a list of one or more LTM candidate target cells for UE 904.

Procedure 900 then proceeds, at step 910, with network entity 902 transmitting an RRCReconfiguration message to UE 904, including configuration information for each of the LTM candidate target cell (s) . UE 904 stores the configuration information received from network entity 902, and at step 912, transmits an RRCReconfigurationComplete message to network entity 902.

Procedure 900 proceeds, at step 914, with UE 904 performing measurements (e.g., L1 measurements) on one or more of the configured LTM candidate cell (s) . UE 904 may transmit, at step 916, lower-layer report (s) , including information about these measurements, to network entity 902.

At step 918, network entity 902 determines to execute an LTM cell switch to one of the LTM candidate cell (s) based on the measurement report (s) received from UE 904. For example, the measurement report (s) received from UE 904 may include RSRP measurement information for one or more LTM candidate cell (s) . Where the RSRP measurement information for one LTM candidate cell satisfies a threshold RSRP value, then network entity 902 may determine to initiate an LTM cell switch to this LTM candidate cell. Accordingly, at step 920, network entity 902 transmits, to UE 904, a MAC-CE triggering an LTM cell switch for UE 904 (also referred to herein as “a cell switch command” ) to the target LTM candidate cell.

In response to receiving the cell switch command, UE 904 begins the process to synchronize with the target LTM candidate cell. In particular, at step 922 and step 924, respectively, UE 904 performs downlink synchronization and uplink synchronization with the target LTM candidate cell. In some cases, performing uplink synchronization includes UE 904 performing a random access channel procedure (RACH) with the target LTM candidate cell. After successful synchronization with the target LTM candidate cell, UE 904 may be switched to the configuration of the target LTM candidate cell.

Procedure 900 then proceeds, at step 926, with UE 904 transmitting an LTM completion message to network entity 902. The LTM completion message helps to inform network entity 902 of the successful completion of the LTM cell switch to the target LTM candidate cell.

At step 928, the target LTM candidate cell (e.g., belonging to network entity 902) and UE 904 perform beam management procedures (e.g., including beam selection and beam refinement procedures described above in FIG. 6) to determine a beam pair with good connectivity to use for communication between the target LTM candidate cell and UE 904. After step 928, procedure 900 is complete and the target LTM candidate cell and UE 904 communicate (e.g., at step 930) using beams of the beam pair determined at step 928.

Aspects Related to Conditional LTM (or UE-Based LTM)

In some aspects, a UE is configured to initiate an LTM procedure, such as procedure 900 described with respect to FIG. 9, based on transmitting a conditional LTM message to a network entity of a source cell in which the UE is communicating. The conditional LTM message may request that the UE switch from communicating on the source cell to communicating on a target cell (e.g., a target LTM candidate cell) .

In some aspects, the source network entity of the source cell confirms receipt of the conditional LTM message, and further initiation of the LTM procedure, based on transmitting a response, to the UE, confirming the request to perform the switch. Immediately, or a period of time after the confirmation message is transmitted by the network and received by the UE, a timer is started to allow the UE and the target network entity of the target cell to prepare for and execute the switch. Preparation and execution of the switch may include, for example, (1) the network entity of the source cell informing the network entity of the target cell about the cell switch and (2) performing downlink and/or uplink synchronization between the UE and the network entity of the target cell (e.g., to enable the UE to access and communicate with the target cell following completion of the LTM procedure) . In other words, at an expiration time of the timer set by the UE and the network entity of the target cell, the UE is expected to be connected to and able to directly communicate with the network entity of the target cell, as well as expected to no longer be connected to and/or in direct communication with the network entity of the source cell.

In some other aspects, a confirmation message is not transmitted by the network entity of the source cell in response to receiving the conditional LTM message from the UE requesting the cell switch. As such, instead of starting a timer after reception of a confirmation message at the UE, the timer is started immediately, or a period of time after, the conditional LTM message is transmitted by the UE and received by the network entity of the source cell.

In some cases, the timer period (also referred to herein as the “duration of the timer” ) set for the timer (e.g., a period from initiation of the timer to an expiration of the timer) is a fixed value defined in a specification (e.g., such as 3GPP specification) . In some other cases, the timer period set for the timer is dynamically configured based on the UE’s capability (e.g., with respect to performing the LTM preparation and execution) . However, in either case, the timer period set for the timer may take into consideration the amount of time needed by the UE and/or one or more network entities (e.g., associated with the source cell and/or the target cell) to prepare for and carry out the switch.

A timer period set for a timer used when performing an intra-DU LTM procedure (e.g., where the target cell belongs to a same DU as the source cell, where the DU is able to support multiple cells) may be different than a timer period set for a timer used when performing an inter-DU LTM procedure (e.g., where the target cell belongs to a different DU than a DU of the source cell) . For example, to account for additional backhaul signaling latency introduced in inter-DU cases due to communication between the source DU and the target DU (e.g., to notify target DU of the switch) , the timer period set for the timer used in the inter-DU LTM procedure may be greater than a timer period set for a timer used in an intra-DU LTM procedure.

Further, in some cases where a confirmation message is transmitted in response to a conditional LTM message transmitted by the UE, an indication of the timer period to use for the timer is included in the confirmation message. In other words, the confirmation message may explicitly indicate the timer period to be used for the preparation and execution of the cell switch. In such cases, the timer period may be based on backhaul latency determined by the network entity associated with the source cell.

In some aspects, a UE is configured to trigger a conditional LTM procedure via transmission of a conditional LTM message based on one or more measured and/or predicted measurement values associated with one or more communication resources of one or more network entities of one or more potential target cells (e.g., referred to as LTM candidate cells) . Specifically, measured and/or predicted resources (e.g., associated with beams of network entity (ies) of LTM candidate cell (s) ) with better channel conditions (e.g., better L1 reference signal received power (RSRP) measurements) than channel conditions of the UE in a source cell may trigger the UE to transmit the conditional LTM request.

As an illustrative example, a UE requesting the LTM procedure, may be configured to predict and/or measure one or more communication resources to assist in determining a set of uplink receive beams and/or a set of downlink transmit beams that may be used by a network entity of a target cell when communicating in the target cell. As used herein, to “predict communication resources” may refer to predicting what the measurement (s) of one or more signals communicated in the communication resources would be, without actually measuring any signals in the communication resources. As such, the UE may predict and/or measure communication resources associated with each of the LTM candidate cells, as in communication resources associated with the network entities of each of the LTM candidate cells. The UE may determine that at least one of the communications resources has a channel condition that meets a criteria, and transmit a conditional LTM message requesting the UE switch from communicating on the source cell to communicating on a target cell associated with the communication resource.

Where the UE identifies the communication resource to the target network entity of the target cell, the target network entity can use an uplink receive beam associated with the communication resource to communicate with the UE. Accordingly, the performance of additional beam management procedures (e.g., for determining a most suitable beam pair for communication) , such as beam sweeping and/or beam refinement, may be avoided. As such, both time and resources may be saved at both the UE and the target network entity of the target cell, thereby improving overall connectivity and reliability.

While there are benefits to informing the network entity of the target cell of predicted and/or measured communication resource (s) , providing such information may not be feasible in certain LTM procedures. In particular, transmission of such information from the UE to the network entity of the source cell, and then from the network entity of the source cell to the network entity of the target cell, may take a longer amount of time than a time period set for a timer (e.g., started after transmission/reception of the conditional LTM message or after transmission/reception of the confirmation message) used in certain LTM procedures. For example, a timer period set for the timer in certain LTM procedures may be short and may not account for non-ideal backhaul signaling (e.g., between the source network entity of the source cell and the target network entity of the target cell) , to allow for a least amount of interruption to the UE’s service (if any) (e.g., by minimizing the timer period, the UE may be expected to switch from the source cell to the target cell in a smaller window of time) . Further, the timer period set for the timer may be short to allow quick handover procedures for UEs experiencing radio link failure (RLF) at a source cell and needing to quickly change to a target cell. Lastly, although a longer timer value set for the timer would allow the predicted beams to be communicated to the network entity of the target cell before the LTM procedure is complete, having a longer timer value runs the risk of communication resources predicted by the UE at the start of the timer becoming outdated when the timer expires, and thus becoming communication resources that are no longer preferred for communication with the UE.

FIGS. 10A and 10B depict issues with informing network entities of target cells of communication resources (e.g., predicted communication resources) in existing LTM procedures. Specifically, FIG. 10A depicts issues with informing network entities of target cells of communication resources in a conditional LTM procedure 1000A where the timer is started immediately, or a period of time after a confirmation message is received by a UE requesting conditional LTM procedure 1000A. FIG. 10B depicts issues with informing network entities of target cells of communication resources in a conditional LTM procedure 1000B where the timer is started immediately or a period of time after a conditional LTM message is transmitted by a UE requesting conditional LTM procedure 1000B.

Conditional LTM procedure 1000A and conditional LTM procedure 1000B depict process flows for communications in a network between a target cell 1002 and a source cell 1004 of a disaggregated network entity (e.g., such as disaggregated BS 200 of FIG. 2) , or a non-disaggregated network entity, and a UE 1006 (e.g., such as UE 104 of FIGS. 1-3) to allow UE 1006 to switch from communicating on source cell 1004 to communicating on target cell 1002. Source cell 1004 may belong to a different DU than target cell 1002, but the DU associated with source cell 1004 and the DU associated with target cell 1002 may be connected to a common CU. As such communications shown as being received by or sent by a cell, may refer to communications received or sent by a network entity (e.g., DU, BS, etc. ) of the cell. Further, beams of a cell may refer to beams of a network entity of the cell.

As illustrated in both FIGS. 10A and 10B, conditional LTM procedure 1000A and conditional LTM procedure 1000B begin, at step 1010, with source cell 1004 sending, to UE 1006, one or more signals in a first set of communication resources. The one or more signals may include synchronization signal blocks (SSBs) , demodulation reference signals (DM-RSs) , and/or channel state information reference signals (CSI-RSs) (e.g., non-zero power (NZP) -CSI-RSs) . The first set of communication resources may be associated with a first set of beams used to transmit the signal (s) , such as one or more downlink transmit beams of source cell 1004.

At step 1012, UE 1006 measures the one or more received signals to obtain a first set of measurements. The first set of measurements may include RSRP, signal to interference plus noise (SINR) , and/or the like.

At step 1014, UE 1006 performs communication resource prediction based on the first set of measurements. For example, UE 1006 processes, with a model (e.g., ML model at or on UE 1006) configured to predict communication resources, the first set of measurements (e.g., obtained at 1012) . Processing the first set of measurements with the model thereby predicts one or more parameters (e.g., a second set of measurements) for one or more sets of communication resources, including a second set of communication resources. The second set of communication resources may be associated with a second set of beams associated with target cell 1002.

In some aspects, UE 1006 selects the second set of communication resources from a plurality of sets of communication resources, such as based on the second set of communication resources having a suitable value (e.g., satisfies a threshold, maximum among the plurality of sets of communication resources, etc. ) of a given criterion, such as predicted channel quality (e.g., RSRP, SINR, and/or the like) .

Conditional LTM procedures 1000A and 1000B then proceed, to step 1016, with UE 1006 determining to trigger a cell switch from source cell 1004 to target cell 1002. UE 1006 may make this determination based on predicted (and/or measured) channel quality of the second set of communication resources (e.g., associated with a second set of beams associated with target cell 1002) being greater than measured channel quality of the first set of communication resources (e.g., associated with a first set of beams associated with source cell 1004) .

Accordingly, at step 1018, UE 1006 sends a conditional LTM message to source cell 1004. The conditional LTM message may be a MAC-CE triggering an LTM cell switch for UE 1006 to the target cell 1002 (e.g., similar to the cell switch command transmitted by a network entity, at step 920 in FIG. 9, to initiate an LTM procedure) .

In conditional LTM procedure 1000A of FIG. 10A, source cell 1004 confirms receipt of the conditional LTM request from UE 1006, and further initiation of the requested conditional LTM procedure, by sending back, to UE 1006, a confirmation message for the conditional LTM message. A timer is then started, at step 1022 (e.g., a time immediately, or a period of time after the confirmation message is received by UE 1006) , to allow UE 1006 and target cell 1002 to prepare for and execute the switch.

A timer period set for the timer may expire at time 1030 shown in FIG. 10A. At the expiration of this timer, UE 1006 is considered to be served by target cell 1002, and no longer served by target cell 1002.

The timer period set for the timer may provide just enough time needed by UE 1006 and/or the network entity, associated with source cell 1004 and target cell 1002, to prepare for and carry out the switch (e.g., at step 1024) . More specifically, the timer period set for the timer may not account for non-ideal backhaul between source cell 1004 and target cell 1002 such that source cell 1004 has enough time to inform target cell 1002 about predicted communication resources (e.g., associated with preferred beams to use for communicating with UE 1006) provided to source cell 1004 from UE 1006. Accordingly, target cell 1002 may not receive any information about predicted communication resources, such as associated with preferred beams to use after time 1030, when the timer expires and UE 1006 is served by target cell 1002.

As such, after time 1030, beam determination and refinement efforts may be necessary to determine a “best” beam pair for communication between target cell 1002 and UE 1006. For example, at step 1026, target cell 1002 and UE 1006 perform beam sweeping and/or beam refinement procedures (e.g., similar to procedures described above in FIG. 6) . At step 1028, UE 1006 then communicates with target cell 1002 using the determined beams.

Similar steps are performed in Conditional LTM procedure 1000B; however, instead of waiting for a confirmation message from source cell 1004, the timer is started immediately, or a period of time after UE 1006 transmits the conditional LTM message at step 1018.

A timer period set for the timer in conditional LTM procedure 1000B may be a different timer period or a same timer period set for the timer in conditional LTM procedure 1000A. However, the timer period for the timer in conditional LTM procedure 1000B may also not account for non-ideal backhaul such that there is sufficient time to inform target cell 1002 of the predicted communication resources (e.g., associated with preferred uplink receive beams of target cell 1002) . Accordingly, beam determination and refinement may also need to be performed by target cell 1002 and UE 1006, after UE 1006 is connected to target cell 1002, in conditional LTM procedure 1000B.

Needing to perform additional beam sweeping and/or refinement features, after UE 1006 has switched cells and is connected to target cell 1002, may result in additional throughput interruption at UE 1006, at least until a beam pair capable of providing sufficient throughput performance for communications between target cell 1002 and UE 1006 is determined. As such, overall reliability and efficiency of wireless communications between UE 1006 and the network may be adversely affected.

The aforementioned technical problems, including throughput interruption, result when using conventional conditional LTM procedures where a timer period set for a timer associated with the procedure does not allow for non-ideal backhaul indications of communication resources; thus, improved techniques are desired.

Aspects Related to Two-Step Conditional LTM Procedures

In order to overcome technical problems associated with existing conditional LTM procedures, such as those described above with respect to FIGS. 10A and 10B, aspects described herein provide techniques for performing a two-step confirmation, conditional LTM procedure where two conditional LTM messages are sent (instead of one conditional LTM message, as done in conventional procedures) to allow for (1) the confirmation of a previous request to initiate an LTM cell switch or (2) the cancellation of the previous request. For example, a first conditional LTM message may be transmitted at a first time, by a UE, requesting that the UE switch from communicating on a source cell to communicating on a target cell. Transmission of the first conditional LTM message may initiate a first timer (either after transmission of the request or after receiving a confirmation message in response to the request) . At an expiration of the first timer, a second conditional LTM message may be transmitted, by the UE, either (1) confirming or (2) requesting cancellation of the earlier request to perform the cell switch. In cases where performance of the cell switch is confirmed, a second timer may be started to allow for preparation and execution of the cell switch. In this way, the second timer is similar to the timer of other conditional LTM procedures. However, unlike other LTM procedures, the addition of the first timer prior in time than the second timer helps to enable reporting of communication resource (s) to the target cell, such as via non-ideal backhaul. As an example, non-ideal backhaul may refer to backhaul with a latency between approximately 2-60ms and a throughput from approximately 10 megabits per second (Mbps) to 10 gigabits per second (Gbps) .

In particular, introduction of the first timer in the conditional LTM procedure helps to extend the time period from when a first conditional LTM message is sent by the UE (e.g., requesting that the UE switch from communicating on the source cell to communicating on the target cell) to when the UE is expected at the target cell (e.g., when the UE is expected to be connected to and in communication with the target cell) . This additional time, provided via use of the first timer, may provide sufficient time to notify the target cell of predicted communication resources (e.g., associated with beams of the target cell) such that beam management procedures, following successful synchronization with the UE, can be avoided. Instead, the target cell may simply use one or more up beams associated with the predicted communication resources, thereby, immediately allowing for good connectivity and thus increased reliability in communications between the UE and the target cell at an expiration of the second timer.

FIGS. 11A and 11B illustrate example reporting (via non-idea backhaul) in conditional LTM procedures 1100A and 1100B, respectively. Conditional LTM procedures 1100A and 1100B illustrate the use of two conditional LTM messages. Conditional LTM procedure 1100A differs from conditional LTM procedures 1100B in that the second conditional LTM message in conditional LTM procedure 1100A is used to confirm the cell switch initiated by a prior first conditional LTM message, whereas the second conditional LTM message in conditional LTM procedure 1100B is used to request the cancellation of a cell switch initiated by a prior first conditional LTM message.

Conditional LTM procedures 1100A and 1100B illustrate the initiation of the first timer after a confirmation message is received from a source cell in response to the first conditional LTM message. Further, in conditional LTM procedure 1100A, the initiation of the second timer also occurs after a confirmation is received from the source cell in response to the second conditional message. As such, although each illustrated timer in conditional LTM procedures 1100A and 1100B is started after a corresponding confirmation message is received, in certain other embodiments, each timer may be started after transmission of a conditional LTM message corresponding to that timer (e.g., previously illustrated in FIG. 10B) .

Conditional LTM procedures 1100A and 1100B depict process flows for communications in a network between a target cell 1102 and a source cell 1104 of a disaggregated network entity (e.g., such as disaggregated BS 200 of FIG. 2) , or a non-disaggregated network entity, and a UE 1106 (e.g., such as UE 104 of FIGS. 1-3) , to allow UE 1106 to switch from communicating on source cell 1104 to communicating on target cell 1102 (e.g., using communication resource prediction techniques described herein) . Source cell 1104 may belong to a different DU than target cell 1102, but the DU associated with source cell 1104 and the DU associated with target cell 1102 may be connected to a common CU.

As illustrated in both FIGS. 11A and 11B, conditional LTM procedures 1100A and 1100B begin, at step 1108, with UE 1106 determining to trigger a cell switch from source cell 1104 to target cell 1102. UE 1106 may make this decision based on measurements of one or more signals transmitted in a first set of communication resources associated with source cell 1104 and one or more predicted (and/or measured) measurement values for a second set of communication resources associated with target cell 1102.

Accordingly, at step 1110 (occurring at a “first time” ) , UE 1106 sends a first conditional LTM message to source cell 1104. The first conditional LTM message may be a MAC-CE triggering an LTM cell switch for UE 1106 to target cell 1102. At step 1112 (occurring at a “third time” ) , source cell 1104 confirms receipt of the conditional LTM message from UE 1106, and further initiation of the requested conditional LTM procedure, by sending, to UE 1006, a confirmation message for the first conditional LTM message.

A first timer is then started, at 1122 (e.g., a time immediately, or a time period after the confirmation message is received by UE 1106) . As described above, a timer period set for the first timer (e.g., from a start of the first timer an expiration of the first timer at time 1120) may be used to extend the amount of time after transmitting a first conditional LTM message and before UE 1106 is connected to the target cell 1102, to enable source cell 1104 to inform target cell 1102 of preferred beam (s) to use for communication with UE 1106 after the successful completion of the switch. As such, at step 1116, source cell 1104 notifies target cell 1102 of predicted resources (e.g., associated with one or more beams) via non-ideal backhaul. An amount of time taken to inform target cell 1102 may be greater than or less than the timer period set for the first timer.

At the expiration of the first timer at time 1120, UE 1106 sends a second conditional LTM message to source cell 1104 (e.g., at step 118, occurring at a “second time” ) . The second conditional LTM message may be a MAC-CE including (1) a confirmation to perform the cell switch previously requested via the first conditional LTM message or (2) a request to cancel the cell switch previously requested via the first conditional LTM message. For example, UE 1106 may determine whether to include, in the second conditional LTM message, (1) the confirmation of the request to switch from communicating on source cell 1104 to communicating on target cell 1102 or (2) the request to cancel the request, such as based on measured or predicted channel characteristics of source cell 1104 and/or measured or predicted channel characteristics of target cell 1102. In particular, predicted channel characteristics of source cell 1104 and/or predicted channel characteristics of target cell 1102 may include predicted future L1-RSRP and/or L1-SINR of communication resources associated with source cell 1104 and/or target cell 1102, such as of the one or more highest L1-RSRP and/or L1-SINR. Further, measured channel characteristics of source cell 1104 may include current detected RLF and/or beam failure between the source cell 1104 and UE 1106. Additionally, predicted channel characteristics of source cell 1104 may include predicted RLF and/or beam failure instance (s) expected between the source cell 1104 and UE 1106 in one or more future occasions.

Conditional LTM procedure 1100A of FIG. 11A illustrates second conditional LTM message including the confirmation of the request to switch from communicating on source cell 1104 to communicating on target cell 1102. Alternatively, conditional LTM procedure 1100B of FIG. 11B illustrates second conditional LTM message including the request to cancel the request to switch from communicating on source cell 1104 to communicating on target cell 1102.

As illustrated in FIG. 11A, in response to receiving the second conditional LTM message sent at step 1118, source cell 1104 sends, at step 1122 (e.g., occurring at a “fourth time” ) , a confirmation message to UE 1106 for the second conditional LTM message. A second timer is then started, at step 1124 (e.g., a time immediately, or soon after the confirmation message is received by UE 1106) . A timer period set for the timer (e.g., expiring at time 1126) may allow for UE 1106 and target cell 1102 to prepare for and execute the switch. Accordingly, at time 1126, UE 1106 may be served by target cell 1102, and no longer served by source cell 1104.

At step 1128, UE 1106 then communicates on target cell 1102, such as using beams associated with predicted communication resources. Target cell 1102 may determine the beams to use based on the indication of the predicted communication resources provided to target cell 1102 from source cell 1104, at step 1116. Accordingly, UE 1106 and target cell 1102 may communicate without performing one or more beam management procedures (e.g., beam sweeping and/or beam refinement) .

Alternatively, as illustrated in FIG. 11B, at step 1130 instead of 1118, the second conditional LTM message may include a request to cancel the request to switch from communicating on source cell 1104 to communicating on target cell 1102. For example, UE 1106 may determine to cancel the original cell switch request based on measured channel characteristics of source cell 1104 changing (e.g., improving) from when the first conditional LTM message was sent to the timing of sending the second conditional LTM message. As another example, UE 1106 may determine to cancel the original cell switch request based on predicted channel characteristics of target cell 1102 changing (e.g., degrading) from when the first conditional LTM message was sent to the timing of sending the second conditional LTM message.

Cancelling the request to switch from communicating on source cell 1104 to communicating on target cell 1102 may end conditional LTM procedure 1100B. As such, UE 1106 may continue to communicate with source cell 1104 (e.g., shown at step 1132 in FIG. 11B) .

In some aspects, the duration of the first timer (e.g., initiated via receipt of a confirmation message from source cell 1104, as illustrated in FIGS. 11A and 11B, or initiated after transmission of the first conditional LTM message) is based on an indication of the duration of the first timer transmitted to UE 1106.

For example, FIG. 12 illustrates a duration of the first timer determined by UE 1106 based on an indication of the duration transmitted by source cell 1104 via an RRC message. Specifically, FIG. 12 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, and 1116 illustrated in FIG. 12 are the same steps 1108, 1110, 1112, 1114, and 1116 described with respect to FIGS. 11A-11B) .

As illustrated at steps 1206 and 1208 in FIG. 12, in some aspects, source cell 1104 determines a duration of the first timer and transmits an indication of the determined duration to UE 1106. The indication of the duration of the first timer may be transmitted to UE 1106 in an RRC message from source cell 1104. The indication of the first timer duration may be transmitted to UE 1106 prior to transmitting the confirmation message for the first conditional LTM request to UE 1106 (e.g., at step 1112) . As such, when UE 1106 receives the confirmation message, UE 1106 may know the duration the first timer is to be initiated with.

In some aspects, source cell 1104 determines (e.g., at step 1206) the first timer duration based on reported time domain beam prediction capabilities of UE 1106. For example, in some cases, at step 1202, UE 1106 transmits, to source cell 1104, an indication of a maximum future time UE 1106 is capable of performing time domain beam prediction (e.g., predicting future measurement values for communication resources) . Thus, at step 1206, source cell 1104 determines the first timer duration based, at least in part, on this information.

In some aspects, source cell 1104 determines (e.g., at step 1206) the first timer duration based on a non-ideal backhaul delay level determined at a prior step 1204. Further, in some aspects, source cell 1104 determines (e.g., at step 1206) the first timer duration based on a non-ideal backhaul delay level determined at step 1204 and the UE 1106's reported time domain beam predictions capabilities (e.g., reported at step 1202) .

FIG. 13 illustrates a duration of the first timer determined based on dynamic updates of the first timer duration from source cell 1104. Specifically, FIG. 13 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, and 1116 illustrated in FIG. 13 are the same steps 1108, 1110, 1112, 1114, and 1116 described with respect to FIGS. 11A-11B) .

As illustrated at steps 1308 and 1310 in FIG. 13, in some aspects, the duration of the first timer is dynamically updated by source cell 1104 transmitting an indication of the first time duration in a MAC-CE or via DCI (e.g., shown at step 1308) , or as an indication in the confirmation message transmitted, at step 1310, in response to the first conditional LTM message.

In some aspects, the duration of the first timer, dynamically updated via the MAC-CE, DCI, or the confirmation message, is determined by source cell 1104 (e.g., at step 1306) based on UE-reported confidence levels associated with time-domain beam prediction results for target cell 1102. For example, UE 1106 may perform communication resource prediction for target cell 1102 at step 1302. More specifically, UE 1106 may predict measurement values for a set of communication resources associated with beams of target cell 1102. At step 1304, UE 1106 may report a confidence level of such predictions to source cell 1104. Source cell 1104 may use this information (e.g., confidence level information) to determine the first timer duration at step 1306.

In some aspects, the duration of the first timer (e.g., initiated via receipt of a confirmation message from source cell 1104, as illustrated in FIGS. 11A and 11B, or initiated after transmission of the first conditional LTM message) is based on a duration recommendation by UE 1106. For example, FIG. 14 illustrates a duration of the first timer determined based on a duration recommended to source cell 1104, from UE 1106.

FIG. 14 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, and 1116 illustrated in FIG. 14 are the same steps 1108, 1110, 1112, 1114, and 1116 described with respect to FIGS. 11A-11B) . As illustrated at step 1402 in FIG. 14, source cell 1104 determine a non-ideal backhaul delay level for signaling between source cell 1104 and target cell 1102. At step 1404, source cell 1104 provides information about the non-ideal backhaul delay level to UE 1106. UE 1106 uses the non-ideal back delay level received from source cell 1104 to determine a duration for the first timer, and transmits a message to source cell 1104 requesting that the first timer duration be equal to the duration determined by UE 1106 (e.g., at step 1406 and 1408) .

At step 1410, source cell 1104 determines the first timer duration. In some aspects, the first timer duration determined by source cell 1104 is based on the requested timer duration received from UE 1106. Source cell 1104 then dynamically updates the duration for the first timer by transmitting an indication of the determined first timer duration in a MAC-CE or DCI, at step 1410, or as an indication included in the confirmation message transmitted from source cell 1104 to UE 1106 at step 1412.

In some aspects, instead of UE 1106 performing time domain communication resource prediction to predict one or more communication resources associated with one or more beams for communication between UE 1106 and target cell 1102 subsequent to the conditional LTM procedure, the prediction is performed by target cell 1102. In cases where target cell 1102 performs the prediction, the duration of the first timer may be based on target cell-reported confidence levels associated with time-domain communication resource prediction results for target cell 1102. In some other cases, the target where target cell 1102 performs the communication resource prediction, the duration of the first timer may be based on a target cell requested timer duration.

FIG. 15 illustrates examples for determining a duration of the first timer in cases where target cell 1102 performs time domain communication resource prediction. Specifically, FIG. 15 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, and 1116 illustrated in FIG. 15 are the same steps 1108, 1110, 1112, 1114, and 1116 described with respect to FIGS. 11A-11B) .

As illustrated in FIG. 15, at step 1502, target cell 1102 performs time domain communication resource prediction. More specifically, target cell 1102 predicts measurement values for a set of communication resources associated with beams of target cell 1102.

In some cases, target cell 1102 determines a duration for the first timer based on the predicted communication resources and transmits a message to source cell 1104 requesting that the first timer duration be equal to the duration determined by UE 1106 (e.g., at step 1504) . In some cases, target cell 1102 reports a confidence level of such communication resource predictions determined by target cell 1102, to source cell 1104 at step 1506.

Source cell 1104 may use the requested first duration and/or the confidence level information to determine the first timer duration at step 1508. Source cell 1104 then dynamically updates the duration for the first timer by transmitting an indication of the determined first timer duration in a MAC-CE or DCI, at step 1510, or as an indication included in the confirmation message transmitted from source cell 1104 to UE 1106 at step 1512.

In some aspects, instead of UE 1106 and/or target cell 1102 performing time domain communication resource prediction, the prediction is performed by source cell 1104. In cases where source cell 1104 performs the prediction, the duration of the first timer may be based on source cell-determined confidence levels associated with time-domain communication resource prediction results for target cell 1102 and/or non-ideal backhaul delay levels.

FIG. 16 illustrates examples for determining a duration of the first timer in cases where source cell 1104 performs time domain communication resource prediction. Specifically, FIG. 16 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, and 1116 illustrated in FIG. 16 are the same steps 1108, 1110, 1112, 1114, and 1116 described with respect to FIGS. 11A-11B) .

As illustrated in FIG. 16, at step 1602, source cell 1104 performs time domain communication resource prediction. More specifically, source cell 1104 predicts measurement values for a set of communication resources associated with beams of target cell 1102. At step 1604, source cell 1104 determines, at step 1604, a confidence level of communication resource predictions determined by source cell 1104. Further, at step 1606, source cell 1104 determines a level of non-ideal backhaul delay for signaling between source cell 1104 and target cell 1102.

Source cell 1104 may use the confidence level information and/or the determined non-ideal backhaul delay level to determine the first timer duration at step 1608. Source cell 1104 then dynamically updates the duration for the first timer by transmitting an indication of the determined first timer duration in a MAC-CE or DCI, at step 1610, or as an indication included in the confirmation message transmitted from source cell 1104 to UE 1106 at step 1612.

In some aspects, UE 1106 is triggered to transmit the first conditional LTM message and/or second conditional LTM message (e.g., at steps 1118 and 1122 inn FIGS. 11A and 11B, respectively) based on one or more conditions.

FIG. 17 depicts example triggering of first and/or second conditional LTM messages based on one or more conditions. It is noted that FIG. 17 illustrates a truncated version of the steps performed in conditional LTM procedures 1100A and 1100B described with respect to FIGS. 11A-11B (e.g., steps 1108, 1110, 1112, 1114, 1116, and 1118 illustrated in FIG. 17 are the same steps 1108, 1110, 1112, 1114, 1116, and 1118 described with respect to FIGS. 11A-11B) . As illustrated in FIG. 17, at step 1704, UE 1106 receives an indication of one or more conditions. The conditions may be used to trigger UE 1106 to send the first conditional LTM message and/or trigger UE 1106 to include the confirmation of the request to perform the cell switch instead of the request to cancel the request in the second conditional LTM message.

In some cases, prior to step 1704, UE 1106 transmits, at step 1701, an indication of one or more recommended conditions. The recommended conditions may include recommended conditions for triggering UE 1106 to send the first conditional LTM message and/or the second conditional LTM message. Accordingly, at step 1702, source cell 1104 determines the conditions to configure UE 1106 with based on one or more of the condition (s) recommended by UE 1106. The determined condition (s) are indicated to UE 1106 at step 1704.

In some aspects, the conditions include a first condition used to trigger transmission of the first conditional LTM message when predicted measurements (e.g., future L1-RSRPs) associated with one or more synchronization signal blocks (SSBs) of target cell 1102, and associated with a particular time, are a first threshold greater than (e.g., are at least 9dB greater than) predicted measurements associated with one or more SSBs of source cell 1104, and associated with the particular time.

In some aspects, the conditions include a second condition used to trigger the transmission of a second conditional LTM message confirming the cell switch initiated by the first conditional LTM message when (1) the first condition is met and (2) when predicted measurements (e.g., L1-RSRPs) associated with one or more SSBBs of target cell 1102, and associated with a second time, are a second threshold greater than (e.g., are at least 6dB greater than) predicted measurements associated with one or more SSBs of source cell 1104, and associated with the second time.

In some aspects, the conditions include a third condition used to trigger the transmission of a second conditional LTM message requesting cancellation of the cell switch initiated by the first conditional LTM message when (1) the first condition is met and (2) when predicted measurements (e.g., L1-RSRPs) associated with one or more SSBBs of target cell 1102, and associated with a second time, are not a second threshold greater than (e.g., are at least 6dB greater than) predicted measurements associated with one or more SSBs of source cell 1104, and associated with the second time.

In some cases, the threshold used for the above-described conditions are be communicated between source cell 1104 and UE 1106. In some other cases, the threshold values are defined in a specification (e.g., the 3GPP specification) . In some other cases, the threshold values are pre-configured at UE 1106 using RRC signaling. In some cases, the threshold values are based on recommendations of threshold value suggested by UE 1106.

As illustrated in FIG. 17, ifat step 1706 at least one condition is met to trigger the transmission of the first conditional LTM message at 1110, then UE 1106 transmits the message to initiate the cell switch from the source cell 1104 to target cell 1102. Further, if, at step 1708, at least one condition is met to trigger the transmission of the second conditional message, including the confirmation to continue with the cell switch, then the second conditional LTM message is transmitted at step 1118 with the confirmation. On the other hand, if, at step 1708, one or more conditions are not met to trigger the transmission of the second conditional message, including the confirmation to continue with the cell switch, and/or at least one condition is met to trigger the transmission of the second conditional message, including the cancellation request, then then the second conditional LTM message is transmitted at step 1118 with the cancellation request.

Example Operations

FIG. 18 shows a method 1800 for wireless communications by an apparatus, such as UE 104 of FIGS. 1 and 3.

Method 1800 begins at step 1805 with sending, at a first time, a first conditional LTM message comprising a request for the apparatus to switch from communicating on a source cell to communicating on a target cell.

Method 1800 then proceeds to step 1810 with sending, at a second time after the first time, a second conditional LTM message comprising one off a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, method 1800 further includes receiving, at a third time after the first time and before the second time, a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and the method 1800 further includes receiving, at a fourth time after the second time, a response confirming the confirmation.

In certain aspects, method 1800 further includes determining whether to include, in the second conditional LTM message, the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell.

In certain aspects, the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and the method 1800 further includes switching, at a third time after the second time, to communicating on the target cell.

In certain aspects, the second time is based on a first timer started at the apparatus after the first time, and the third time is based on a second timer started at the apparatus after the second time.

In certain aspects, method 1800 further includes receiving an indication of a duration of the first timer.

In certain aspects, receiving the indication of the duration of the first timer includes: receiving the indication of the duration of the first timer in a RRC message.

In certain aspects, method 1800 further includes sending an indication of a maximum future time the apparatus is capable of performing time domain beam prediction, wherein the duration of the first timer is based on the maximum future time.

In certain aspects, receiving the indication of the duration of the first timer includes: receiving the indication of the duration of the first timer in one off a MAC-CE; a downlink control information; or a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, method 1800 further includes sending an indication of a confidence level associated with a predicted measurement associated with a transmit beam of the target cell, wherein the duration of the first timer is based on the confidence level.

In certain aspects, method 1800 further includes sending an indication of a requested duration for the first timer.

In certain aspects, method 1800 further includes receiving an indication of one or more conditions for triggering the apparatus to at least one of: send the first conditional LTM message, or include the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell in the second conditional LTM message instead of the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, the one or more conditions comprise one or more of: a first condition comprising one or more first predicted measurements associated with one or more first synchronization signal blocks of the target cell and associated with a first time being a first threshold greater than one or more second predicted measurements associated with one or more second synchronization signal blocks of the source cell and associated with the first time.

In certain aspects, the one or more conditions comprise a second condition comprising one or more third predicted measurements associated with one or more third synchronization signal blocks of the target cell and associated with a second time being a second threshold greater than one or more fourth predicted measurements associated with one or more fourth synchronization signal blocks of the source cell and associated with a second time, the first condition is associated with triggering the apparatus to send the first conditional LTM message, and the second condition is associated with triggering the apparatus to include the confirmation in the second conditional LTM message.

In certain aspects, method 1800 further includes receiving an indication of the first threshold and the second threshold.

In certain aspects, method 1800 further includes sending an indication of the first threshold and the second threshold.

In certain aspects, method 1800 further includes sending an indication of one or more recommended conditions for triggering the apparatus to send at least one of the first conditional LTM message or the second conditional LTM message.

In certain aspects, method 1800, or any aspect related to it, may be performed by an apparatus, such as communications device 2000 of FIG. 20, which includes various components operable, configured, or adapted to perform the method 1800. Communications device 2000 is described below in further detail.

Note that FIG. 18 is just one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with this disclosure.

FIG. 19 shows a method 1900 for wireless communications by an apparatus, such as BS 102 of FIGS. 1 and 3, or a disaggregated base station as discussed with respect to FIG. 2.

Method 1900 begins at step 1905 with receiving, at a first time, a first conditional LTM message comprising a request for a UE to switch from communicating on a source cell to communicating on a target cell of the apparatus.

Method 1900 then proceeds to step 1910 with receiving, at a second time after the first time, a second conditional LTM message comprising one of: a confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, method 1900 further includes transmitting, at a third time after the first time and before the second time, a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and the method 1900 further includes transmitting, at a fourth time after the second time, a response confirming the confirmation.

In certain aspects, the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell by the UE.

In certain aspects, the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and the method 1900 further includes switching, at a third time after the second time, to communicating with the UE via the target cell.

In certain aspects, the second time is based on a first timer started at the UE after the first time, and the third time is based on a second timer started at the UE after the second time.

In certain aspects, method 1900 further includes transmitting an indication of a duration of the first timer.

In certain aspects, transmitting the indication of the duration of the first timer includes: transmitting the indication of the duration of the first timer in a RRC message.

In certain aspects, method 1900 further includes receiving an indication of a maximum future time the UE is capable of performing time domain beam prediction, wherein the duration of the first timer is based on the maximum future time.

In certain aspects, transmitting the indication of the duration of the first timer includes: transmitting the indication of the duration of the first timer in one of: a MAC-CE; a downlink control information; or a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, method 1900 further includes receiving an indication of a confidence level associated with a predicted measurement associated with a transmit beam of the target cell, wherein the duration of the first timer is based on the confidence level.

In certain aspects, transmitting the indication of the duration of the first timer includes: transmitting the indication of the duration of the first timer from the source cell, wherein the target cell is configured to send an indication to the source cell of a suggested duration for the first timer or a confidence level associated with a predicted measurement associated with a transmit beam of the target cell to be used to determine the duration of the first timer.

In certain aspects, method 1900 further includes receiving an indication of a requested duration for the first timer.

In certain aspects, method 1900 further includes transmitting an indication of one or more conditions for triggering the UE to at least one of: send the first conditional LTM message, or include the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell in the second conditional LTM message instead of the request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.

In certain aspects, the one or more conditions comprise a second condition comprising one or more third predicted measurements associated with one or more third synchronization signal blocks of the target cell and associated with a second time being a second threshold greater than one or more fourth predicted measurements associated with one or more fourth synchronization signal blocks of the source cell and associated with a second time, the first condition is associated with triggering the UE to send the first conditional LTM message, and the second condition is associated with triggering the UE to include the confirmation in the second conditional LTM message.

In certain aspects, method 1900 further includes transmitting an indication of the first threshold and the second threshold.

In certain aspects, method 1900 further includes receiving an indication of the first threshold and the second threshold.

In certain aspects, method 1900 further includes receiving an indication of one or more recommended conditions for triggering the UE to send at least one of the first conditional LTM message or the second conditional LTM message.

In certain aspects, method 1900, or any aspect related to it, may be performed by an apparatus, such as communications device 2100 of FIG. 21, which includes various components operable, configured, or adapted to perform the method 1900. Communications device 2100 is described below in further detail.

Note that FIG. 19 is just one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with this disclosure.

Example Communications Devices

FIG. 20 depicts aspects of an example communications device 2000. In some aspects, communications device 2000 is a user equipment, such as UE 104 described above with respect to FIGS. 1 and 3.

The communications device 2000 includes a processing system 2005 coupled to a transceiver 2065 (e.g., a transmitter and/or a receiver) . The transceiver 2065 is configured to transmit and receive signals for the communications device 2000 via an antenna 2070, such as the various signals as described herein. The processing system 2005 may be configured to perform processing functions for the communications device 2000, including processing signals received and/or to be transmitted by the communications device 2000.

The processing system 2005 includes one or more processors 2010. In various aspects, the one or more processors 2010 may be representative of one or more of receive processor 358, transmit processor 364, TX MIMO processor 366, and/or controller/processor 380, as described with respect to FIG. 3. The one or more processors 2010 are coupled to a computer-readable medium/memory 2035 via a bus 2060. In certain aspects, the computer-readable medium/memory 2035 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 2010, enable and cause the one or more processors 2010 to perform the method 1800 described with respect to FIG. 18, or any aspect related to it, including any additional steps or sub-steps described in relation to FIG. 18. Note that reference to a processor performing a function of communications device 2000 may include one or more processors performing that function of communications device 2000, such as in a distributed fashion.

In the depicted example, computer-readable medium/memory 2035 stores code for sending 2040, code for receiving 2045, code for determining 2050, and code for switching 2055. Processing of the code 2040-2055 may enable and cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, or any aspect related to it.

The one or more processors 2010 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 2035, including circuitry for sending 2015, circuitry for receiving 2020, circuitry for determining 2025, and circuitry for switching 2030. Processing with circuitry 2015-2030 may enable and cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, or any aspect related to it.

More generally, means for communicating, transmitting, sending or outputting for transmission may include the transceivers 354, antenna (s) 352, transmit processor 364, TX MIMO processor 366, and/or controller/processor 380 of the UE 104 illustrated in FIG. 3, transceiver 2065 and/or antenna 2070 of the communications device 2000 in FIG. 20, and/or one or more processors 2010 of the communications device 2000 in FIG. 20. Means for communicating, receiving or obtaining may include the transceivers 354, antenna (s) 352, receive processor 358, and/or controller/processor 380 of the UE 104 illustrated in FIG. 3, transceiver 2065 and/or antenna 2070 of the communications device 2000 in FIG. 20, and/or one or more processors 2010 of the communications device 2000 in FIG. 20.

FIG. 21 depicts aspects of an example communications device 2100. In some aspects, communications device 2100 is a network entity, such as BS 102 of FIGS. 1 and 3, or a disaggregated base station as discussed with respect to FIG. 2.

The communications device 2100 includes a processing system 2105 coupled to a transceiver 2155 (e.g., a transmitter and/or a receiver) and/or a network interface 2165. The transceiver 2155 is configured to transmit and receive signals for the communications device 2100 via an antenna 2160, such as the various signals as described herein. The network interface 2165 is configured to obtain and send signals for the communications device 2100 via communications link (s) , such as a backhaul link, midhaul link, and/or fronthaul link as described herein, such as with respect to FIG. 2. The processing system 2105 may be configured to perform processing functions for the communications device 2100, including processing signals received and/or to be transmitted by the communications device 2100.

The processing system 2105 includes one or more processors 2110. In various aspects, one or more processors 2110 may be representative of one or more of receive processor 338, transmit processor 320, TX MIMO processor 330, and/or controller/processor 340, as described with respect to FIG. 3. The one or more processors 2110 are coupled to a computer-readable medium/memory 2130 via a bus 2150. In certain aspects, the computer-readable medium/memory 2130 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 2110, enable and cause the one or more processors 2110 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it, including any additional steps or sub-steps described in relation to FIG. 19. Note that reference to a processor of communications device 2100 performing a function may include one or more processors of communications device 2100 performing that function, such as in a distributed fashion.

In the depicted example, the computer-readable medium/memory 2130 stores code for receiving 2135, code for transmitting 2140, and code for switching 2145. Processing of the code 2135-2145 may enable and cause the communications device 2100 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it.

The one or more processors 2110 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 2130, including circuitry for receiving 2115, circuitry for transmitting 2120, and circuitry for switching 2125. Processing with circuitry 2115-2125 may enable and cause the communications device 2100 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it.

More generally, means for communicating, transmitting, sending or outputting for transmission may include the transceivers 332, antenna (s) 334, transmit processor 320, TX MIMO processor 330, and/or controller/processor 340 of the BS 102 illustrated in FIG. 3, transceiver 2155 and/or antenna 2160 of the communications device 2100 in FIG. 21, and/or one or more processors 2110 of the communications device 2100 in FIG. 21. Means for communicating, receiving or obtaining may include the transceivers 332, antenna (s) 334, receive processor 338, and/or controller/processor 340 of the BS 102 illustrated in FIG. 3, transceiver 2155 and/or antenna 2160 of the communications device 2100 in FIG. 21, and/or one or more processors 2110 of the communications devie 2100 in FIG. 21.

Example Clauses

Implementation examples are described in the following numbered clauses:

Clause 1: A method for wireless communications by an apparatus, comprising: sending, at a first time, a first conditional LTM message comprising a request for the apparatus to switch from communicating on a source cell to communicating on a target cell; and sending, at a second time after the first time, a second conditional LTM message comprising one of: a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Clause 2: The method of Clause 1, further comprising: receiving, at a third time after the first time and before the second time, a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Clause 3: The method of Clause 2, wherein the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and wherein the method further comprises: receiving, at a fourth time after the second time, a response confirming the confirmation.

Clause 4: The method of any one of Clauses 1-3, further comprising: determining whether to include, in the second conditional LTM message, the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell.

Clause 5: The method of any one of Clauses 1-4, wherein the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and wherein the method further comprises: switching, at a third time after the second time, to communicating on the target cell.

Clause 6: The method of Clause 5, wherein: the second time is based on a first timer started at the apparatus after the first time, and the third time is based on a second timer started at the apparatus after the second time.

Clause 7: The method of Clause 6, further comprising: receiving an indication of a duration of the first timer.

Clause 8: The method of Clause 7, wherein receiving the indication of the duration of the first timer comprises: receiving the indication of the duration of the first timer in a RRC message.

Clause 9: The method of Clause 8, further comprising: sending an indication of a maximum future time the apparatus is capable of performing time domain beam prediction, wherein the duration of the first timer is based on the maximum future time.

Clause 10: The method of Clause 7, wherein receiving the indication of the duration of the first timer comprises: receiving the indication of the duration of the first timer in one of: a MAC-CE; a downlink control information; or a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Clause 11: The method of Clause 10, further comprising: sending an indication of a confidence level associated with a predicted measurement associated with a transmit beam of the target cell, wherein the duration of the first timer is based on the confidence level.

Clause 12: The method of Clause 6, further comprising: sending an indication of a requested duration for the first timer.

Clause 13: The method of Clause 12, further comprising: receiving an indication of a duration of the first timer.

Clause 14: The method of any one of Clauses 1-13, further comprising: receiving an indication of one or more conditions for triggering the apparatus to at least one of: send the first conditional LTM message, or include the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell in the second conditional LTM message instead of the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.

Clause 15: The method of Clause 14, wherein the one or more conditions comprise one or more of: a first condition comprising one or more first predicted measurements associated with one or more first synchronization signal blocks of the target cell and associated with a first time being a first threshold greater than one or more second predicted measurements associated with one or more second synchronization signal blocks of the source cell and associated with the first time.

Clause 16: The method of Clause 15, wherein: the one or more conditions comprise a second condition comprising one or more third predicted measurements associated with one or more third synchronization signal blocks of the target cell and associated with a second time being a second threshold greater than one or more fourth predicted measurements associated with one or more fourth synchronization signal blocks of the source cell and associated with a second time, the first condition is associated with triggering the apparatus to send the first conditional LTM message, and the second condition is associated with triggering the apparatus to include the confirmation in the second conditional LTM message.

Clause 17: The method of Clause 16, further comprising: receiving an indication of the first threshold and the second threshold.

Clause 18: The method of Clause 16, further comprising: sending an indication of the first threshold and the second threshold.

Clause 19: The method of any one of Clauses 1-18, further comprising: sending an indication of one or more recommended conditions for triggering the apparatus to send at least one of the first conditional LTM message or the second conditional LTM message.

Clause 20: A method for wireless communications by an apparatus, comprising: receiving, at a first time, a first conditional LTM message comprising a request for a UE to switch from communicating on a source cell to communicating on a target cell of the apparatus; and receiving, at a second time after the first time, a second conditional LTM message comprising one of: a confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, or a request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.

Clause 21: The method of Clause 20, further comprising: transmitting, at a third time after the first time and before the second time, a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.

Clause 22: The method of Clause 21, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and wherein the method further comprises: transmitting, at a fourth time after the second time, a response confirming the confirmation.

Clause 23: The method of any one of Clauses 20-22, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell by the UE.

Clause 24: The method of any one of Clauses 20-23, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and wherein the method further comprises: switching, at a third time after the second time, to communicating with the UE via the target cell.

Clause 25: The method of Clause 24, wherein: the second time is based on a first timer started at the UE after the first time, and the third time is based on a second timer started at the UE after the second time.

Clause 26: The method of Clause 25, further comprising: transmitting an indication of a duration of the first timer.

Clause 27: The method of Clause 26, wherein transmitting the indication of the duration of the first timer comprises: transmitting the indication of the duration of the first timer in a RRC message.

Clause 28: The method of Clause 27, further comprising: receiving an indication of a maximum future time the UE is capable of performing time domain beam prediction, wherein the duration of the first timer is based on the maximum future time.

Clause 29: The method of Clause 26, wherein transmitting the indication of the duration of the first timer comprises: transmitting the indication of the duration of the first timer in one of: a MAC-CE; a downlink control information; or a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.

Clause 30: The method of Clause 29, further comprising: receiving an indication of a confidence level associated with a predicted measurement associated with a transmit beam of the target cell, wherein the duration of the first timer is based on the confidence level.

Clause 31: The method of Clause 26, wherein transmitting the indication of the duration of the first timer comprises: transmitting the indication of the duration of the first timer from the source cell, wherein the target cell is configured to send an indication to the source cell of a suggested duration for the first timer or a confidence level associated with a predicted measurement associated with a transmit beam of the target cell to be used to determine the duration of the first timer.

Clause 32: The method of Clause 25, further comprising: receiving an indication of a requested duration for the first timer.

Clause 33: The method of Clause 32, further comprising: transmitting an indication of a duration of the first timer.

Clause 34: The method of any one of Clauses 20-33, further comprising: transmitting an indication of one or more conditions for triggering the UE to at least one of: send the first conditional LTM message, or include the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell in the second conditional LTM message instead of the request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.

Clause 35: The method of Clause 34, wherein the one or more conditions comprise one or more of: a first condition comprising one or more first predicted measurements associated with one or more first synchronization signal blocks of the target cell and associated with a first time being a first threshold greater than one or more second predicted measurements associated with one or more second synchronization signal blocks of the source cell and associated with the first time.

Clause 36: The method of Clause 35, wherein: the one or more conditions comprise a second condition comprising one or more third predicted measurements associated with one or more third synchronization signal blocks of the target cell and associated with a second time being a second threshold greater than one or more fourth predicted measurements associated with one or more fourth synchronization signal blocks of the source cell and associated with a second time, the first condition is associated with triggering the UE to send the first conditional LTM message, and the second condition is associated with triggering the UE to include the confirmation in the second conditional LTM message.

Clause 37: The method of Clause 36, further comprising: transmitting an indication of the first threshold and the second threshold.

Clause 38: The method of Clause 36, further comprising: receiving an indication of the first threshold and the second threshold.

Clause 39: The method of any one of Clauses 20-38, further comprising: receiving an indication of one or more recommended conditions for triggering the UE to send at least one of the first conditional LTM message or the second conditional LTM message.

Clause 40: One or more apparatuses, comprising: one or more memories comprising executable instructions; and one or more processors configured to execute the executable instructions and cause the one or more apparatuses to perform a method in accordance with any one of clauses 1-39.

Clause 41: One or more apparatuses, comprising means for performing a method in accordance with any one of clauses 1-39.

Clause 42: One or more non-transitory computer-readable media comprising executable instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform a method in accordance with any one of clauses 1-39.

Clause 43: One or more computer program products embodied on one or more computer-readable storage media comprising code for performing a method in accordance with any one of clauses 1-39.

Additional Considerations

The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limiting of the scope, applicability, or aspects set forth in the claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various actions may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP) , an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC) , or any other such configuration.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

As used herein, “coupled to” and “coupled with” generally encompass direct coupling and indirect coupling (e.g., including intermediary coupled aspects) unless stated otherwise. For example, stating that a processor is coupled to a memory allows for a direct coupling or a coupling via an intermediary aspect, such as a bus.

The methods disclosed herein comprise one or more actions for achieving the methods. The method actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and/or use of specific actions may be modified without departing from the scope of the claims. Further, the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor.

The following claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims. Reference to an element in the singular is not intended to mean only one unless specifically so stated, but rather “one or more. ” For example, reference to an element (e.g., “a processor, ” “a controller, ” “a memory, ” etc. ) , unless otherwise specifically stated, should be understood to refer to one or more elements (e.g., “one or more processors, ” “one or more controllers, ” “one or more memories, ” etc. ) . The terms “set” and “group” are intended to include one or more elements, and may be used interchangeably with “one or more. ” Where reference is made to one or more elements performing functions (e.g., steps of a method) , one element may perform all functions, or more than one element may collectively perform the functions. When more than one element collectively performs the functions, each function need not be performed by each of those elements (e.g., different functions may be performed by different elements) and/or each function need not be performed in whole by only one element (e.g., different elements may perform different sub-functions of a function) . Similarly, where reference is made to one or more elements configured to cause another element (e.g., an apparatus) to perform functions, one element may be configured to cause the other element to perform all functions, or more than one element may collectively be configured to cause the other element to perform the functions. Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

An apparatus configured for wireless communications, comprising:

one or more memories comprising processor-executable instructions; and

one or more processors configured to execute the processor-executable instructions and cause the apparatus to:

send, at a first time, a first conditional lower-layer triggered mobility (LTM) message comprising a request for the apparatus to switch from communicating on a source cell to communicating on a target cell; and

send, at a second time after the first time, a second conditional LTM message comprising one of:

a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or

a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 1, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive, at a third time after the first time and before the second time, a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 2, wherein the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive, at a fourth time after the second time, a response confirming the confirmation.
The apparatus of claim 1, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

determine whether to include, in the second conditional LTM message, the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell.
The apparatus of claim 1, wherein the second conditional LTM message comprises the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, and wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

switch, at a third time after the second time, to communicating on the target cell.
The apparatus of claim 5, wherein:

the second time is based on a first timer started at the apparatus after the first time, and

the third time is based on a second timer started at the apparatus after the second time.
The apparatus of claim 6, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive an indication of a duration of the first timer.
The apparatus of claim 7, wherein, to receive the indication of the duration of the first timer, the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive the indication of the duration of the first timer in a radio resource control (RRC) message.
The apparatus of claim 8, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

send an indication of a maximum future time the apparatus is capable of performing time domain beam prediction, wherein the duration of the first timer is based on the maximum future time.
The apparatus of claim 7, wherein, to receive the indication of the duration of the first timer, the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive the indication of the duration of the first timer in one of:

a medium access control (MAC) control element (MAC-CE) ;

a downlink control information; or

a response confirming the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 10, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

send an indication of a confidence level associated with a predicted measurement associated with a transmit beam of the target cell, wherein the duration of the first timer is based on the confidence level.
The apparatus of claim 6, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

send an indication of a requested duration for the first timer.
The apparatus of claim 12, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive an indication of a duration of the first timer.
The apparatus of claim 1, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive an indication of one or more conditions for triggering the apparatus to at least one of:

send the first conditional LTM message, or

include the confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell in the second conditional LTM message instead of the request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 14, wherein the one or more conditions comprise one or more of:

a first condition comprising one or more first predicted measurements associated with one or more first synchronization signal blocks of the target cell and associated with a first time being a first threshold greater than one or more second predicted measurements associated with one or more second synchronization signal blocks of the source cell and associated with the first time.
The apparatus of claim 15, wherein:

the one or more conditions comprise a second condition comprising one or more third predicted measurements associated with one or more third synchronization signal blocks of the target cell and associated with a second time being a second threshold greater than one or more fourth predicted measurements associated with one or more fourth synchronization signal blocks of the source cell and associated with a second time,

the first condition is associated with triggering the apparatus to send the first conditional LTM message, and

the second condition is associated with triggering the apparatus to include the confirmation in the second conditional LTM message.
The apparatus of claim 16, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

receive an indication of the first threshold and the second threshold.
The apparatus of claim 16, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

send an indication of the first threshold and the second threshold.
The apparatus of claim 1, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

send an indication of one or more recommended conditions for triggering the apparatus to send at least one of the first conditional LTM message or the second conditional LTM message.
An apparatus configured for wireless communications, comprising:

one or more memories comprising processor-executable instructions; and

one or more processors configured to execute the processor-executable instructions and cause the apparatus to:

receive, at a first time, a first conditional lower-layer triggered mobility (LTM) message comprising a request for a user equipment (UE) to switch from communicating on a source cell to communicating on a target cell of the apparatus; and

receive, at a second time after the first time, a second conditional LTM message comprising one of:

a confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, or

a request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 20, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

transmit, at a third time after the first time and before the second time, a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.
The apparatus of claim 21, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

transmit, at a fourth time after the second time, a response confirming the confirmation.
The apparatus of claim 20, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell or the request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell based on at least one of measured or predicted channel characteristics of the source cell or measured or predicted channel characteristics of the target cell by the UE.
The apparatus of claim 20, wherein the second conditional LTM message comprises the confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, and wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

switch, at a third time after the second time, to communicating with the UE via the target cell.
The apparatus of claim 24, wherein:

the second time is based on a first timer started at the UE after the first time, and

the third time is based on a second timer started at the UE after the second time.
The apparatus of claim 25, wherein the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

transmit an indication of a duration of the first timer.
The apparatus of claim 26, wherein, to transmit the indication of the duration of the first timer, the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

transmit the indication of the duration of the first timer in a radio resource control (RRC) message.
The apparatus of claim 26, wherein, to transmit the indication of the duration of the first timer, the one or more processors are configured to execute the processor-executable instructions and cause the apparatus to:

transmit the indication of the duration of the first timer in one of:

a medium access control (MAC) control element (MAC-CE) ;

a downlink control information; or

a response confirming the request for the UE to switch from communicating on the source cell to communicating on the target cell.
A method for wireless communications by an apparatus, comprising:

sending, at a first time, a first conditional lower-layer triggered mobility (LTM) message comprising a request for the apparatus to switch from communicating on a source cell to communicating on a target cell; and

sending, at a second time after the first time, a second conditional LTM message comprising one of:

a confirmation of the request for the apparatus to switch from communicating on the source cell to communicating on the target cell, or

a request to cancel the request for the apparatus to switch from communicating on the source cell to communicating on the target cell.
A method for wireless communications by an apparatus, comprising:

receiving, at a first time, a first conditional lower-layer triggered mobility (LTM) message comprising a request for a user equipment (UE) to switch from communicating on a source cell to communicating on a target cell of the apparatus; and

receiving, at a second time after the first time, a second conditional LTM message comprising one of:

a confirmation of the request for the UE to switch from communicating on the source cell to communicating on the target cell, or

a request to cancel the request for the UE to switch from communicating on the source cell to communicating on the target cell.