WO2025209441A1

WO2025209441A1 - Methods for connected-mode mobility enhancements with tiered radio resource management

Info

Publication number: WO2025209441A1
Application number: PCT/CN2025/086514
Authority: WO
Inventors: Din-Hwa Huang; Chia-Hao Yu; Li-Chuan Tseng; Cheng-Rung Tsai; Jiann-Ching Guey
Original assignee: MediaTek Inc
Current assignee: MediaTek Inc
Priority date: 2024-04-03
Filing date: 2025-04-01
Publication date: 2025-10-09
Anticipated expiration: 2026-10-03

Abstract

Various solutions for connected-mode mobility enhancements with tiered radio resource management (RRM) are described. An apparatus may perform a first measurement based on a first downlink (DL) reference signal (RS) received from each of a source network node and a target network node. The first DL RS includes identification information of a single frequency network (SFN) area without identification information of any network node. Also, the apparatus may perform a second measurement based on a second DL RS received from each of the source network node and the target network node. The second DL RS includes identification information of the source network node or the target network node. Then, the apparatus may transmit a switching request including information of the target network node to the source network node based on the first measurement and the second measurement, and receive a switching command from the source network node.

Description

METHODS FOR CONNECTED-MODE MOBILITY ENHANCEMENTS WITH TIERED RADIO RESOURCE MANAGEMENT

CROSS REFERENCE TO RELATED PATENT APPLICATION (S)

The present disclosure is part of a non-provisional application claiming the priority benefit of U.S. Patent Application No. 63/573, 559, filed 3 April 2024, the content of which herein being incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure is generally related to mobile communications and, more particularly, to connected-mode mobility enhancements with tiered radio resource management (RRM) with respect to user equipment (UE) and network nodes in mobile communications.

BACKGROUND

Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.

For current network implementations, one base station (BS) is operable to provide radio coverage to a specific geographical area using one or more cells to form a radio access network. The BS may support the operations of the cell (s) , and each cell may be operable to provide services to at least one UE within its radio coverage. In order to reduce inter-cell interference, a multiple transmission reception points (TRPs) architecture is supported in 5^th generation (5G) New Radio (NR) by allowing dynamic coordination between the multi-TRPs to provide joint scheduling and transmissions/receptions. As such, a UE, e.g., at the cell edge, may be served by multi-TRPs to improve its signal transmission/reception, which contributes to increased throughput.

However, there are some issues with the current framework of RRM and mobility management in 5G NR. For example, the current synchronization signal block (SSB) design is node and beam aware, where each TRP transmits a respective SSB in a beam sweeping manner and the UE needs to perform beam sweeping for monitoring the SSB from each TRP. This SSB design not only causes increased power consumption (e.g., due to the beamforming operations) for both UE and network (NW) , but also results in inefficient radio resource utilization (e.g., due to different SSBs having mostly the same content other than the physical broadcast channel (PBCH) part) . Furthermore, this SSB design may result in more frequent cell switching for connected-mode UE under dense network deployment, and the RRM latency for connected-mode UE under dense network deployment may lead to slow cell switching which further causes throughput degradation at the cell-edge.

Accordingly, how to improve the framework of RRM and mobility management becomes an important topic for modern wireless communication systems. Therefore, there is a need to provide proper schemes to address the above-described issues.

SUMMARY

The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is provided to introduce concepts, highlights, benefits and advantages of the novel and non-obvious techniques described herein. Select implementations are further described below in the detailed description. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

One objective of the present disclosure is proposing schemes, concepts, designs, systems, methods and apparatus pertaining to tiered RRM with connected-mode mobility management in mobile communications. It is believed that the above-described issues would be avoided or otherwise alleviated by implementing one or more of the proposed schemes described herein.

In one aspect, a method may involve an apparatus (e.g., a connected-mode UE) performing a first measurement based on a first downlink (DL) reference signal (RS) received from each of a source network node and a target network node, wherein the first DL RS comprises identification information of a single frequency network (SFN) area without identification information of any network node. The method may also involve the apparatus performing a second measurement based on a second DL RS received from each of the source network node and the target network node, wherein the second DL RS comprises identification information of the source network node or the target network node. The method may further involve the apparatus transmitting a switching request to the source network node based on the first measurement and the second measurement, wherein the switching request comprises information of the target network node. The method may further involve the apparatus receiving a switching command from the source network node, wherein the switching command indicates the apparatus to switch from the source network node to the target network node.

In one aspect, a method may involve a source network node (e.g., a TRP or a radio unit (RU) ) transmitting a first DL RS to an apparatus, wherein the first DL RS comprises identification information of an SFN area without identification information of any network node. The method may also involve the source network node transmitting a second DL RS to the apparatus, wherein the second DL RS comprises identification information of the source network node. The method may further involve the source network node receiving a switching request from the apparatus, wherein the switching request comprises information of a target network node. The method may further involve the source network node transmitting a switching command to the apparatus, wherein the switching command indicates the apparatus to switch from the source network node to the target network node.

In one aspect, a method may involve a target network node (e.g., a TRP or RU) transmitting a first DL RS to an apparatus, wherein the first DL RS comprises identification information of an SFN area without identification information of any network node. The method may also involve the target network node transmitting a second DL RS to the apparatus, wherein the second DL RS comprises identification information of the target network node. The method may further involve the target network node receiving a mobility request for the apparatus from a source network node, and transmitting a mobility acknowledgement to the source network node. The method may further involve the target network node receiving a complete message from the apparatus, wherein the complete message indicates that the apparatus has switched from the source network node to the target network node.

It is noteworthy that, although description provided herein may be in the context of certain radio access technologies, networks and network topologies such as Long-Term Evolution (LTE) , LTE-Advanced, LTE-Advanced Pro, 5^th Generation (5G) , New Radio (NR) , Internet-of-Things (IoT) and Narrow Band Internet of Things (NB-IoT) , Industrial Internet of Things (IIoT) , beyond 5G (B5G) , and 6^th Generation (6G) , the proposed concepts, schemes and any variation (s) /derivative (s) thereof may be implemented in, for and by other types of radio access technologies, networks and network topologies. Thus, the scope of the present disclosure is not limited to the examples described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of the present disclosure. The drawings illustrate implementations of the disclosure and, together with the description, serve to explain the principles of the disclosure. It is appreciable that the drawings are not necessarily in scale as some components may be shown to be out of proportion than the size in actual implementation in order to clearly illustrate the concept of the present disclosure.

FIG. 1 is a diagram depicting an example scenario of the current framework of RRM and mobility management in 5G NR.

FIG. 2 is a diagram depicting an example scenario of tiered RRM framework in accordance with an implementation of the present disclosure.

FIG. 3 is a diagram depicting an example scenario of connected-mode mobility under the tiered RRM framework in accordance with an implementation of the present disclosure.

FIG. 4 is a diagram depicting an example scenario of an intra-SFN mobility procedure in accordance with an implementation of the present disclosure.

FIG. 5 is a diagram depicting an example scenario of PRACH transmission features in accordance with an implementation of the present disclosure.

FIG. 6 is a diagram depicting an example scenario of an inter-SFN mobility procedure in accordance with an implementation of the present disclosure.

FIG. 7 is a diagram depicting another example scenario of an inter-SFN mobility procedure in accordance with an implementation of the present disclosure.

FIG. 8 is a block diagram of an example communication system in accordance with an implementation of the present disclosure.

FIG. 9 is a flowchart of an example process in accordance with an implementation of the present disclosure.

FIG. 10 is a flowchart of another example process in accordance with an implementation of the present disclosure.

FIG. 11 is a flowchart of yet another example process in accordance with an implementation of the present disclosure.
DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATIONS

Detailed embodiments and implementations of the claimed subject matters are disclosed herein. However, it shall be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matters which may be embodied in various forms. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that description of the present disclosure is thorough and complete and will fully convey the scope of the present disclosure to those skilled in the art. In the description below, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments and implementations.
Overview

Implementations in accordance with the present disclosure relate to various techniques, methods, schemes and/or solutions pertaining to tiered RRM with connected-mode mobility management in mobile communications. According to the present disclosure, a number of possible solutions may be implemented separately or jointly. That is, although these possible solutions may be described below separately, two or more of these possible solutions may be implemented in one combination or another.

In 5G NR, the current framework of RRM and mobility management is based on the node and beam aware SSB design. FIG. 1 illustrates an example scenario 100 of the current framework of RRM and mobility management in 5G NR. Part (A) of FIG. 1 depicts multiple TRPs 121-127 within a cell 120, where each of the TRPs 121-127 transmits a respective SSB (denoted as SSB 1 to SSB 7) in a beam sweeping manner. Part (B) of FIG. 1 depicts the time and frequency resource allocation for the SSB transmissions of all TRPs within the cell 120, where the SSBs of different TRPs are transmitted in separate time domain resources within the SSB period. Part (C) of FIG. 1 depicts the SSB structure including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for synchronization purpose, and a PBCH which contains the demodulation reference signal (DMRS) and data. For example, the PSS and/or the SSS may carry the cell identifier (ID) of the cell 120, and the PBCH may carry master information block (MIB) information and SSB index. For a UE (not shown) within the cell coverage, it may detect the following information from the SSB (s) : (i) the cell ID for identifying the cell 120, (ii) the SSB index for identifying a TRP, (iii) the PBCH content other than the SSB index information, which has been transmitted repeatedly for multiple times, and it cannot be saved from transmission due to the beam sweeping architecture in frequency range 2 (FR2) , and (iv) L1/L3 measurement RS which are combined as an SSB. However, as mentioned previously, this SSB design not only causes increased power consumption (e.g., due to the beamforming operations) for both UE and NW, but also results in inefficient radio resource utilization (e.g., due to different SSBs having mostly the same content other than the PBCH part) . Furthermore, this SSB design may result in more frequent cell switching for connected-mode UE under dense network deployment, and the RRM latency for connected-mode UE under dense network deployment may lead to slow cell switching which further causes throughput degradation at the cell-edge.

In view of the above, the present disclosure proposes a number of schemes pertaining to connected-mode mobility enhancements with tiered RRM, aiming to solve the above-described issues. According to the schemes of the present disclosure, a tiered RRM framework is provided with 1^st-tier DL RS (or called cell-specific DL RS) and 2^nd-tier DL RS (or called TRP-specific DL RS) , wherein 2^nd-tier DL RS is time-division multiplexed (TDM’ ed) with the 1^st-tier DL RS to parallelize cell-level and TRP-level measurements. Furthermore, connected-mode mobility enhancements under the tiered RRM framework are provided to support the following: (i) fast intra-SFN/cell mobility and inter-SFN/cell mobility based on both the cell-level and TRP-level measurements; (ii) early synchronization with TRPs is determined by UE; (iii) (cell and) TRP switching request is sent by the UE to multiple TRPs based on the timing reference of the anchor TRP (or called source TRP) ; and (iv) for timing advance (TA) acquisition, physical random access channel (PRACH) signal is sent by the UE to the target TRP based on the timing reference of the target TRP. Accordingly, by applying the schemes of the present disclosure, overall system performance with respect to UE and network operations in connected mode (e.g., RRC_CONNECTED mode) may be improved.

FIG. 2 illustrates an example scenario 200 of tiered RRM framework in accordance with an implementation of the present disclosure. Part (A) of FIG. 2 depicts a communication environment involving a UE 210 in wireless communication with one or more of multiple TRPs (or radio units (RUs) ) 221-227 within an SFN area (e.g., a cell) 220, where all of the TRPs 221-227 transmits the same 1^st-tier DL RS, i.e., an SFN SSB, without beamforming or with beamforming that is UE transparent. Specifically, the SFN SSB includes identification information of the SFN area 220 without identification information of any TRP. That is, the SFN SSB may allow identification of a cell (e.g., can be used for cell reselection) , but may not allow identification of a TRP within the cell coverage. In addition to the SFN SSB, each of the TRPs 221-227 also transmits a respective 2^nd-tier DL RS, i.e., a TRP RS. Specifically, the TRP RS includes identification information of a respective TRP (e.g., a TRP ID) . That is, this TRP-specific signal may allow identification of a TRP (e.g., can be used for TRP selection) , but may not allow identification of TRPs between different SFN areas. Part (B) of FIG. 2 depicts the time and frequency resource allocation for the SFN SSB and TRP RS transmissions of all TRPs within the SFN area 220, where the SFN SSB and the TRP RS are transmitted in separate time domain resources (e.g., the TRP RS is transmitted after the SFN SSB) to avoid resource competition between L1 measurement and L3 measurement. The UE 210 may perform (and report) a L3 measurement based on the SFN SSB for rough time-frequency tracking, and perform a L1 measurement based on the TRP RS for fine time-frequency tracking. Accordingly, the SFN control node (e.g., a distributed unit (DU) or a BS) and/or the UE 210 may perform idle-mode mobility management based on the SFN SSB, and perform connected-mode mobility management (e.g., intra-SFN/cell mobility and inter-SFN/cell mobility) based on the TRP RS.

In some implementations, the SFN SSB may occupy a narrow bandwidth. For example, similar to the concept of synchronization signal and PBCH in 5G NR system, the SFN SSB may include a synchronization signal (or called DU-specific RS) (e.g., either both PSS and SSS, or simply one of PSS and SSS) and a PBCH.

In some implementations, the SFN SSB may be regularly transmitted. For example, the SFN SSB may be periodically or semi-periodically transmitted.

In some implementations, the TRP RS may occupy a narrow or wide bandwidth. For example, similar to the concept of synchronization signal in 5G NR system, the TRP RS may include a synchronization signal (e.g., SSS) . The TRP RS may be a multi-port RS for spatial domain parameter estimation/acquisition. the TRP RS may be configurable by, e.g., broadcast information (or system information) as a form of, e.g., a channel state information-reference signal (CSI-RS) , such that the pattern, resource element occupation, and bandwidth of the TRP RS would be more flexible. Additionally, or optionally, the TRP RS may be associated with more than one occasion per TRP, with each occasion is corresponding to different spatial domain properties.

When compared to the legacy beam-sweeping SSB, the SFN SSB in FIG. 2 is transmitted in a non-beam-sweeping manner which may have some benefits, including better spectral efficiency (e.g., due to SFN diversity gain and lower code rate from multiple redundancy versions (RVs) of PBCH) , network energy saving from reduced transmission (Tx) time or reduced number of active TRPs, and simplified UE background-mode complexity (e.g., due to early termination from repetitive reception and reduced reception (Rx) time from higher spectral efficiency) . As to the TRP RS, there may be some design features to enable fast TRP/beam tracking, including (i) it is discoverable (e.g., the TRP RS is consisting of low cross correlation sequences) , (ii) multiple TDM’ ed ports (or beams) is used for the analog part of hybrid beamforming (e.g., frequency-division multiplexed (FDM’ ed) for all-digital architecture) , and (iii) it is suitable for compressed sensing.

FIG. 3 illustrates an example scenario 300 of connected-mode mobility under the tiered RRM framework in accordance with an implementation of the present disclosure. Scenario 300 depicts two types of connected-mode mobility, including inter-SFN/cell mobility and intra-SFN/cell mobility, in the proposed tiered RRM framework. As shown in FIG. 3, UE 1 undergoes an inter-SFN/cell mobility from SFN area 1 (e.g., cell 1) to SFN area 2 (e.g., cell 2) , and more particularly, from TRP 2 of SFN area 1 to TRP 3 of SFN area 2. In addition, UE 2 undergoes an intra-SFN/cell mobility within SFN area 1 (i.e., from TRP 6 of SFN area 1 to TRP 2 of SFN area 1) , while UE 3 undergoes an intra-SFN/cell mobility within SFN area 2 (i.e., from TRP 7 of SFN area 2 to TRP 1 of SFN area 2) .

FIG. 4 illustrates an example scenario 400 of an intra-SFN mobility procedure in accordance with an implementation of the present disclosure. To begin with, the UE first connects to one or more TRPs, including a source TRP, to operate in the connected mode. In step 401, the UE receives the same SFN SSB from multiple TRPs, including the source TRP and a target TRP, within the same SFN area. The UE may perform L3 measurement based on the SFN SSB for cell search (CS) or for connection management (CM) . In step 402, the UE receives different TRP RSs from multiple TRPs, including the source TRP and the target TRP, within the same SFN area. The UE may perform L3 and L1 measurements based on the SFN SSB and/or the TRP RS (s) for TRP selection/update. In step 403, the UE receives a UE-specific RRC configuration (e.g., UE-specific RACH configuration) . In one example, the UE may select the target TRP (s) that has better signal quality than the source TRP based on the measurement results (e.g., signal quality indicators, such as reference signal received power (RSRP) , reference signal received quality (RSRQ) , received signal strength indicator (RSSI) , signal-to-noise ratio (SNR) , or RF signature, of the source TRP and the target TRP) , and then perform early synchronization with the selected target TRP (s) based on the UE-specific RRC configuration.

Then, in step 404, the UE triggers the transmission of a TRP switching request based on the measurement results. The TRP switching request may be transmitted on the physical uplink shared channel (PUSCH) , where the PUSCH resource may be granted via a scheduling request (SR) procedure, or via a (group) configured grant PUSCH. In one example, the TRP switching request may be transmitted in a random access preamble (e.g., MsgA of 2-step RACH) based on the reference timing of the source TRP (e.g., assuming the source TRP and the target TRP are in cyclic prefix (CP) level synchronization) . In one example, the PUSCH resource may be common for both the source TRP and the target TRP, such that the preamble transmission (i.e., the TRP switching request transmission) may be received by both the source TRP and the target TRP. More specifically, the TRP switching request may include the TRP selection results, e.g., information of the target TRP (s) selected by the UE. The TRP selection results may include information (e.g., TRP IDs and corresponding signal quality indicators) of a list of TRPs which the UE has completed early synchronization with, and optionally the receiving timing difference (s) (or referred to as round-trip delay (RTD) ) between the source TRP and the target TRP (s) . Additionally, or optionally, the TRP switching request may include a UE ID (e.g. cell-radio network temporary identifier (C-RNTI) to be used in contention-based random access (CBRA) procedure) .

Next, in step 405, the source TRP transmits a mobility request for the UE to the target TRP, e.g., to inform that the UE requests to switch from the source TRP to the target TRP. In step 406, the target TRP transmits a mobility acknowledgement to the source TRP. In step 407, the source TRP transmits a TRP switching command to the UE. In one example, the TRP switching command may be transmitted in a random access response (e.g., MsgB of 2-step RACH) . The TRP switching command may include the DL and/or UL resources associated with the target TRP, and optionally the TA value of the target TRP. In one example, if UE-based TA acquisition is applied (i.e., the UE can calculate the TA value of the target TRP by itself) , then the TA value of the target TRP is not provided in the TRP switching command. In another example, if NW-based TA acquisition is applied (i.e., the source TRP and the target TRP can cooperate to derive the TA value of the target TRP based on UE reported RTD) , then the network-derived TA value of the target TRP is provided in the TRP switching command. Upon receiving the TRP switching command, the UE may apply the target TRP’s setting (e.g., the DL/UL resources and the TA value) to switch from the source TRP to the target TRP. In step 408, the UE transmits an RRC complete message to the target TRP to complete the intra-SFN mobility procedure.

FIG. 5 illustrates an example scenario 500 of PRACH transmission features in accordance with an implementation of the present disclosure. Part (A) of FIG. 5 depicts the case of L1/L2-triggered mobility in 5G NR, where the source TRP and the target TRP are not well timing-synchronized. In this case, the UL pre-synchronization to a target TRP is performed based on dedicated PRACH, the PRACH Tx is triggered by NW-sent physical downlink control channel (PDCCH) order, and the timing reference and the pathloss reference are the target TRP. Part (B) of FIG. 5 depicts the case of an intra-SFN mobility procedure in the present disclosure, where the source TRP and the candidate TRPs are well timing-synchronized (e.g., the clock error between TRPs can be calibrated by the UE, and the UE can report reception timing difference between TRPs) . In this case, the UL pre-synchronization to multiple candidate TRPs is performed based on common PRACH, the PRACH Tx is triggered by the UE itself (e.g., under certain condition) , and the timing reference and the pathloss reference are the source TRP.

FIG. 6 illustrates an example scenario 600 of an inter-SFN mobility procedure in accordance with an implementation of the present disclosure. To begin with, the UE first connects to one or more TRPs, including a source TRP, to operate in the connected mode. In step 601, the UE receives the same SFN SSB from multiple TRPs, including the source TRP and a target TRP, within different SFN areas. The UE may perform L3 measurement based on the SFN SSB for CS/CM. In step 602, the UE receives different TRP RSs from multiple TRPs, including the source TRP and the target TRP, within different SFN areas. The UE may perform L3 and L1 measurements based on the SFN SSB and/or the TRP RS (s) for TRP selection/update. In step 603, the UE receives a UE-specific RRC configuration including candidate TRP configuration. In one example, the UE may select the target TRP (s) that has better signal quality than the source TRP based on the measurement results, and then perform early synchronization with the selected target TRP (s) based on the UE-specific RRC configuration. Then, in step 604, the UE triggers the transmission of a Cell-and-TRP switching request based on the measurement results. The detailed description of the Cell-and-TRP switching request is similar to the TRP switching request as aforementioned in scenario 400 of FIG. 4, except that the Cell-and-TRP switching request includes the cell and TRP selection results (e.g., the TRP list information may further include the cell ID for each selected TRP) .

Next, in step 605, the source TRP transmits a mobility request for the UE to the target TRP, e.g., to inform that the UE requests to switch from the source TRP to the target TRP. In step 606, the target TRP transmits a mobility acknowledgement to the source TRP. In step 607, the source TRP transmits a Cell-and-TRP switching command to the UE. The detailed description of the Cell-and-TRP switching command is similar to the TRP switching command as aforementioned in scenario 400 of FIG. 4, except that the Cell-and-TRP switching command further includes a PRACH triggering indication to indicate the UE to transmit a PRACH signal to the target TRP. In step 608, upon reception of the Cell-and-TRP switching command, the UE transmits a PRACH signal to the target TRP. In step 609, the target TRP calculates the TA value between the UE and the target TRP based on the PRACH signal, and then transmits the TA value (denoted as TA_t) to the UE. In step 610, the UE transmits an RRC complete message to the target TRP to complete the inter-SFN mobility procedure.

FIG. 7 illustrates an example scenario 700 of an inter-SFN mobility procedure in accordance with an implementation of the present disclosure. Scenario 700 is similar to scenario 600, except that the PRACH transmission is triggered before the Cell-and-TRP switching command. Specifically, steps 701-706 are similar to steps 601-606 in scenario 600, and then in step 707, the source TRP transmits a PRACH triggering indication (e.g., a PDCCH order, a medium access control (MAC) control element (CE) , or an RRC-based signaling) to the UE in response to receiving the mobility acknowledgement from the target TRP. In step 708, upon reception of the PRACH triggering indication, the UE transmits a PRACH signal to the target TRP. In step 709, the target TRP calculates the TA value between the UE and the target TRP based on the PRACH signal, and then transmits the TA value (denoted as TA_t) to the source TRP. Next, in step 710, the source TRP transmits a Cell-and-TRP switching command (without PRACH triggering indication) to the UE. Upon receiving the Cell-and-TRP switching command, the UE may apply the target cell’s setting and the target TRP’s setting (e.g., the DL/UL resources and the TA value) to switch from the source TRP to the target TRP. In step 711, the UE transmits an RRC complete message to the target TRP to complete the inter-SFN mobility procedure.
Illustrative Implementations

FIG. 8 illustrates an example communication system 800 having an example communication apparatus 810 and an example network apparatus 820 in accordance with an implementation of the present disclosure. Each of communication apparatus 810 and network apparatus 820 may perform various functions to implement schemes, techniques, processes and methods described herein pertaining to tiered RRM with connected-mode mobility management in mobile communications, including scenarios/schemes described above as well as processes 900, 1000, and 1100 described below.

Communication apparatus 810 may be a part of an electronic apparatus, which may be a UE such as a portable or mobile apparatus, a wearable apparatus, a wireless communication apparatus or a computing apparatus. For instance, communication apparatus 810 may be implemented in a smartphone, a smartwatch, a personal digital assistant, an electronic control unit (ECU) in a vehicle, a digital camera, or a computing equipment such as a tablet computer, a laptop computer or a notebook computer. Communication apparatus 810 may also be a part of a machine type apparatus, which may be a ReCap UE, an IoT, NB-IoT, eMTC, IIoT UE such as an immobile or a stationary apparatus, a home apparatus, a roadside unit (RSU) , a wire communication apparatus or a computing apparatus. For instance, communication apparatus 810 may be implemented in a smart thermostat, a smart fridge, a smart door lock, a wireless speaker or a home control center. Alternatively, communication apparatus 810 may be implemented in the form of one or more integrated-circuit (IC) chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction set computing (RISC) processors, or one or more complex-instruction-set-computing (CISC) processors. Communication apparatus 810 may include at least some of those components shown in FIG. 8 such as a processor 812, for example. Communication apparatus 810 may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device) , and, thus, such component (s) of communication apparatus 810 are neither shown in FIG. 8 nor described below in the interest of simplicity and brevity.

Network apparatus 820 may be a part of an electronic apparatus, which may be a network node such as a TRP, an RU, a small cell, a router or a gateway of a wireless network. For instance, network apparatus 820 may be implemented in a TRP/RU in a 4G/5G/6G, IoT, NB-IoT or IIoT network. Alternatively, network apparatus 820 may be implemented in the form of one or more IC chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, or one or more RISC or CISC processors. Network apparatus 820 may include at least some of those components shown in FIG. 8 such as a processor 822, for example. Network apparatus 820 may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device) , and, thus, such component (s) of network apparatus 820 are neither shown in FIG. 8 nor described below in the interest of simplicity and brevity.

In one aspect, each of processor 812 and processor 822 may be implemented in the form of one or more single-core processors, one or more multi-core processors, or one or more CISC processors. That is, even though a singular term “a processor” is used herein to refer to processor 812 and processor 822, each of processor 812 and processor 822 may include multiple processors in some implementations and a single processor in other implementations in accordance with the present disclosure. In another aspect, each of processor 812 and processor 822 may be implemented in the form of hardware (and, optionally, firmware) with electronic components including, for example and without limitation, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors and/or one or more varactors that are configured and arranged to achieve specific purposes in accordance with the present disclosure. In other words, in at least some implementations, each of processor 812 and processor 822 is a special-purpose machine specifically designed, arranged and configured to perform specific tasks, including connected-mode mobility enhancements with tiered RRM, in a device (e.g., as represented by communication apparatus 810) and a network node (e.g., as represented by network apparatus 820) in accordance with various implementations of the present disclosure.

In some implementations, communication apparatus 810 may also include a transceiver 816 coupled to processor 812 and capable of wirelessly transmitting and receiving data. In some implementations, transceiver 816 may be capable of wirelessly communicating with different types of UEs and/or wireless networks of different RATs, such as 4G/5G/B5G/6G. In some implementations, transceiver 816 may be equipped with a plurality of antenna ports (not shown) such as, for example, four antenna ports. That is, transceiver 816 may be equipped with multiple transmit antennas and multiple receive antennas for beamforming and MIMO wireless communications. In some implementations, network apparatus 820 may also include a transceiver 826 coupled to processor 822. Transceiver 826 may include a transceiver capable of wirelessly transmitting and receiving data. In some implementations, transceiver 826 may be capable of wirelessly communicating with different types of UEs of different RATs. In some implementations, transceiver 826 may be equipped with a plurality of antenna ports (not shown) such as, for example, four antenna ports. That is, transceiver 826 may be equipped with multiple transmit antennas and multiple receive antennas for beamforming and MIMO wireless communications.

In some implementations, communication apparatus 810 may further include a memory 814 coupled to processor 812 and capable of being accessed by processor 812 and storing data therein. In some implementations, network apparatus 820 may further include a memory 824 coupled to processor 822 and capable of being accessed by processor 822 and storing data therein. Each of memory 814 and memory 824 may include a type of random-access memory (RAM) such as dynamic RAM (DRAM) , static RAM (SRAM) , thyristor RAM (T-RAM) and/or zero-capacitor RAM (Z-RAM) . Alternatively, or additionally, each of memory 814 and memory 824 may include a type of read-only memory (ROM) such as mask ROM, programmable ROM (PROM) , erasable programmable ROM (EPROM) and/or electrically erasable programmable ROM (EEPROM) . Alternatively, or additionally, each of memory 814 and memory 824 may include a type of non-volatile random-access memory (NVRAM) such as flash memory, solid-state memory, ferroelectric RAM (FeRAM) , magnetoresistive RAM (MRAM) and/or phase-change memory.

Each of communication apparatus 810 and network apparatus 820 may be a communication entity capable of communicating with each other using various proposed schemes in accordance with the present disclosure. For illustrative purposes and without limitation, a description of capabilities of communication apparatus 810, as a UE, and network apparatus 820, as a source or target network node (e.g., TRP or RU) , is provided below with processes 900, 1000, and 1100.
Illustrative Processes

FIG. 9 illustrates an example process 900 in accordance with an implementation of the present disclosure. Process 900 may be an example implementation of above scenarios/schemes, whether partially or completely, with respect to connected-mode mobility enhancements with tiered RRM. Process 900 may represent an aspect of implementation of features of communication apparatus 810. Process 900 may include one or more operations, actions, or functions as illustrated by one or more of blocks 910 to 940. Although illustrated as discrete blocks, various blocks of process 900 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of process 900 may be executed in the order shown in FIG. 9 or, alternatively, in a different order. Process 900 may be implemented by communication apparatus 810 or any suitable UE or machine type devices. Solely for illustrative purposes and without limitation, process 900 is described below in the context of communication apparatus 810 (as a UE) . Process 900 may begin at block 910.

At block 910, process 900 may involve processor 812 of communication apparatus 810, performing, via transceiver 816, a first measurement based on a first DL RS received from each of a source network node and a target network node, wherein the first DL RS comprises identification information of an SFN area without identification information of any network node. Process 900 may proceed from block 910 to block 920.

At block 920, process 900 may involve processor 812 performing, via transceiver 816, a second measurement based on a second DL RS received from each of the source network node and the target network node, wherein the second DL RS comprises identification information of the source network node or the target network node. Process 900 may proceed from block 920 to block 930.

At block 930, process 900 may involve processor 812 transmitting, via transceiver 816, a switching request to the source network node based on the first measurement and the second measurement, wherein the switching request comprises information of the target network node. Process 900 may proceed from block 930 to block 940.

At block 940, process 900 may involve processor 812 receiving, via transceiver 816, a switching command from the source network node, wherein the switching command indicates communication apparatus 810 to switch from the source network node to the target network node.

In some implementations, the switching request may be transmitted based on a reference timing of the source network node.

In some implementations, the switching request may be transmitted also to the target network node by using an UL resource common for both the source network node and the target network node.

In some implementations, process 900 may further involve processor 812 performing, via transceiver 816, an early synchronization with the target network node before the transmission of the switching request.

In some implementations, the switching request may be transmitted using a PUSCH resource that is granted via a SR procedure or configured via an RRC signaling.

In some implementations, the switching request may be transmitted in a random access preamble, and the switching command may be received in a random access response.

In some implementations, the information of the target network node may include at least one of the following: (i) an ID of the target network node; (ii) a signal quality indicator of the target network node; (iii) a receiving time difference between the source network node and the target network node; and (iv) an ID of communication apparatus 810.

In some implementations, the switching command may include at least one of the following: (i) a TA value associated with target network node; (ii) a PRACH triggering indication that indicates communication apparatus 810 to transmit a PRACH signal to the target network node; and (iii) at least one of a DL resource and an UL resource associated with the target network node.

In some implementations, process 900 may further involve processor 812 transmitting, via transceiver 816, a PRACH signal to the target network node responsive to the switching command or a PRACH triggering indication received from the source network node, wherein the PRACH signal is transmitted based on a reference timing of the target network node. Additionally, process 900 may further involve processor 812 receiving, via transceiver 816, a TA value associated with target network node, wherein the TA value is received from the target network node or received in the switching command.

In some implementations, process 900 may further involve processor 812 switching, via transceiver 816, from the source network node to the target network node responsive to the switching command, and transmitting, via transceiver 816, a complete message to the target network node, wherein the complete message indicates that communication apparatus 810 has switched from the source network node to the target network node.

FIG. 10 illustrates an example process 1000 in accordance with an implementation of the present disclosure. Process 1000 may be an example implementation of above scenarios/schemes, whether partially or completely, with respect to connected-mode mobility enhancements with tiered RRM. Process 1000 may represent an aspect of implementation of features of network apparatus 820. Process 1000 may include one or more operations, actions, or functions as illustrated by one or more of blocks 1010 to 1040. Although illustrated as discrete blocks, various blocks of process 1000 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of process 1000 may be executed in the order shown in FIG. 10 or, alternatively, in a different order. Process 1000 may be implemented by network apparatus 820 or any suitable network node. Solely for illustrative purposes and without limitation, process 1000 is described below in the context of communication apparatus 810, as a UE, and network apparatus 820, as a source network node (e.g., TRP/RU) . Process 1000 may begin at block 1010.

At block 1010, process 1000 may involve processor 822 of network apparatus 820 transmitting, via transceiver 826, a first DL RS to communication apparatus 810, wherein the first DL RS comprises identification information of an SFN area without identification information of any network node. Process 1000 may proceed from block 1010 to block 1020.

At block 1020, process 1000 may involve processor 822 transmitting, via transceiver 826, a second DL RS to communication apparatus 810, wherein the second DL RS comprises identification information of network apparatus 820. Process 1000 may proceed from block 1020 to block 1030.

At block 1030, process 1000 may involve processor 822 receiving, via transceiver 826, a switching request from communication apparatus 810, wherein the switching request comprises information of a target network node. Process 1000 may proceed from block 1030 to block 1040.

At block 1040, process 1000 may involve processor 822 transmitting, via transceiver 826, a switching command to communication apparatus 810, wherein the switching command indicates communication apparatus 810 to switch from network apparatus 820 to the target network node.

In some implementations, process 1000 may further involve processor 822 transmitting, via transceiver 826, a mobility request for communication apparatus 810 to the target network node responsive to the switching request, and receiving, via transceiver 826, a mobility acknowledgement from the target network node.

In some implementations, the switching command may be transmitted responsive to the mobility acknowledgement.

In some implementations, process 1000 may further involve processor 822 transmitting, via transceiver 826, a PRACH triggering indication to communication apparatus 810 responsive to the mobility acknowledgement, wherein the PRACH triggering indication indicates communication apparatus 810 to transmit a PRACH signal to the target network node. Additionally, process 1000 may further involve processor 822 receiving, via transceiver 826, a TA value determined based on the PRACH signal from the target network node, wherein the switching command is transmitted responsive to the TA value.

In some implementations, the switching request may be received using a PUSCH resource that is granted via a SR procedure or configured via an RRC signaling.

In some implementations, the switching request may be received in a random access preamble, and the switching command may be transmitted in a random access response.

In some implementations, the switching request may indicate that an early synchronization with the target network node has been completed, and the information of the target network node may include at least one of the following: (i) an ID of the target network node; (ii) a signal quality indicator of the target network node; (iii) a receiving time difference between network apparatus 820 and the target network node; and (iv) an ID of communication apparatus 810.

FIG. 11 illustrates an example process 1100 in accordance with an implementation of the present disclosure. Process 1100 may be an example implementation of above scenarios/schemes, whether partially or completely, with respect to connected-mode mobility enhancements with tiered RRM. Process 1100 may represent an aspect of implementation of features of network apparatus 820. Process 1100 may include one or more operations, actions, or functions as illustrated by one or more of blocks 1110 to 1150. Although illustrated as discrete blocks, various blocks of process 1100 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of process 1100 may be executed in the order shown in FIG. 11 or, alternatively, in a different order. Process 1100 may be implemented by network apparatus 820 or any suitable network node. Solely for illustrative purposes and without limitation, process 1100 is described below in the context of communication apparatus 810, as a UE, and network apparatus 820, as a target network node (e.g., TRP/RU) . Process 1100 may begin at block 1110.

At block 1110, process 1100 may involve processor 822 of network apparatus 820 transmitting, via transceiver 826, a first DL RS to communication apparatus 810, wherein the first DL RS comprises identification information of an SFN area without identification information of any network node. Process 1100 may proceed from block 1110 to block 1120.

At block 1120, process 1100 may involve processor 822 transmitting, via transceiver 826, a second DL RS to communication apparatus 810, wherein the second DL RS comprises identification information of network apparatus 820. Process 1100 may proceed from block 1120 to block 1130.

At block 1130, process 1100 may involve processor 822 receiving, via transceiver 826, a mobility request for communication apparatus 810 from a source network node. Process 1100 may proceed from block 1130 to block 1140.

At block 1140, process 1100 may involve processor 822 transmitting, via transceiver 826, a mobility acknowledgement to the source network node. Process 1100 may proceed from block 1140 to block 1150.

At block 1150, process 1100 may involve processor 822 receiving, via transceiver 826, a complete message from communication apparatus 810, wherein the complete message indicates that the apparatus has switched from the source network node to network apparatus 820.

In some implementations, process 1100 may further involve processor 822 receiving, via transceiver 826, a PRACH signal from communication apparatus 810, and transmitting, via transceiver 826, a TA value associated with network apparatus 820 to communication apparatus 810 or the source network node before the reception of the RRC complete message, wherein the TA value is determined based on the PRACH signal.
Additional Notes

The herein-described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected" , or "operably coupled" , to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable" , to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

Further, with respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

Moreover, it will be understood by those skilled in the art that, in general, terms used herein, and especially in the appended claims, e.g., bodies of the appended claims, are generally intended as “open” terms, e.g., the term “including” should be interpreted as “including but not limited to, ” the term “having” should be interpreted as “having at least, ” the term “includes” should be interpreted as “includes but is not limited to, ” etc. It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to implementations containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an, " e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more; ” the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number, e.g., the bare recitation of "two recitations, " without other modifiers, means at least two recitations, or two or more recitations. Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. In those instances where a convention analogous to “at least one of A, B, or C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B. ”

From the foregoing, it will be appreciated that various implementations of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various implementations disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

A method, comprising:

performing, by a processor of an apparatus, a first measurement based on a first downlink (DL) reference signal (RS) received from each of a source network node and a target network node, wherein the first DL RS comprises identification information of a single frequency network (SFN) area without identification information of any network node;

performing, by the processor, a second measurement based on a second DL RS received from each of the source network node and the target network node, wherein the second DL RS comprises identification information of the source network node or the target network node;

transmitting, by the processor, a switching request to the source network node based on the first measurement and the second measurement, wherein the switching request comprises information of the target network node; and

receiving, by the processor, a switching command from the source network node, wherein the switching command indicates the apparatus to switch from the source network node to the target network node.
The method of Claim 1, wherein the switching request is transmitted based on a reference timing of the source network node.
The method of Claim 1, wherein the switching request is transmitted also to the target network node by using an uplink (UL) resource common for both the source network node and the target network node.
The method of Claim 1, further comprising:

performing, by the processor, an early synchronization with the target network node before the transmission of the switching request.
The method of Claim 1, wherein the switching request is transmitted using a physical uplink shared channel (PUSCH) resource that is granted via a scheduling request (SR) procedure or configured via a radio resource control (RRC) signaling.
The method of Claim 1, wherein the switching request is transmitted in a random access preamble, and the switching command is received in a random access response.
The method of Claim 1, wherein the information of the target network node comprises at least one of the following:

an identifier (ID) of the target network node;

a signal quality indicator of the target network node;

a receiving time difference between the source network node and the target network node; and

an ID of the apparatus.
The method of Claim 1, wherein the switching command comprises at least one of the following:

a timing advance (TA) value associated with target network node;

a physical random access channel (PRACH) triggering indication that indicates the apparatus to transmit a PRACH signal to the target network node; and

at least one of a downlink (DL) resource and an uplink (UL) resource associated with the target network node.
The method of Claim 1, further comprising:

transmitting, by the processor, a physical random access channel (PRACH) signal to the target network node responsive to the switching command or a PRACH triggering indication received from the source network node, wherein the PRACH signal is transmitted based on a reference timing of the target network node; and

receiving, by the processor, a timing advance (TA) value associated with target network node, wherein the TA value is received from the target network node or received in the switching command.
The method of Claim 1, further comprising:

switching, by the processor, from the source network node to the target network node responsive to the switching command; and

transmitting, by the processor, a complete message to the target network node, wherein the complete message indicates that the apparatus has switched from the source network node to the target network node.
A method, comprising:

transmitting, by a processor of a source network node, a first downlink (DL) reference signal (RS) to an apparatus, wherein the first DL RS comprises identification information of a single frequency network (SFN) area without identification information of any network node;

transmitting, by the processor, a second DL RS to the apparatus, wherein the second DL RS comprises identification information of the source network node;

receiving, by the processor, a switching request from the apparatus, wherein the switching request comprises information of a target network node; and

transmitting, by the processor, a switching command to the apparatus, wherein the switching command indicates the apparatus to switch from the source network node to the target network node.
The method of Claim 11, further comprising:

transmitting, by the processor, a mobility request for the apparatus to the target network node responsive to the switching request; and

receiving, by the processor, a mobility acknowledgement from the target network node.
The method of Claim 12, wherein the switching command is transmitted responsive to the mobility acknowledgement.
The method of Claim 12, further comprising:

transmitting, by the processor, a physical random access channel (PRACH) triggering indication to the apparatus responsive to the mobility acknowledgement, wherein the PRACH triggering indication indicates the apparatus to transmit a PRACH signal to the target network node; and

receiving, by the processor, a timing advance (TA) value determined based on the PRACH signal from the target network node, wherein the switching command is transmitted responsive to the TA value.
The method of Claim 11, wherein the switching request is received using a physical uplink shared channel (PUSCH) resource that is granted via a scheduling request (SR) procedure or configured via a radio resource control (RRC) signaling.
The method of Claim 11, wherein the switching request is received in a random access preamble, and the switching command is transmitted in a random access response.
The method of Claim 11, wherein the switching request indicates that an early synchronization with the target network node has been completed, and the information of the target network node comprises at least one of the following:

an identifier (ID) of the target network node;

a signal quality indicator of the target network node;

a receiving time difference between the source network node and the target network node; and

an ID of the apparatus.
The method of Claim 11, wherein the switching command comprises at least one of the following:

a timing advance (TA) value associated with target network node;

a physical random access channel (PRACH) triggering indication that indicates the apparatus to transmit a PRACH signal to the target network node; and

at least one of a downlink (DL) resource and an uplink (UL) resource associated with the target network node.
A method, comprising:

transmitting, by a processor of a target network node, a first downlink (DL) reference signal (RS) to an apparatus, wherein the first DL RS comprises identification information of a single frequency network (SFN) area without identification information of any network node;

transmitting, by the processor, a second DL RS to the apparatus, wherein the second DL RS comprises identification information of the target network node;

receiving, by the processor, a mobility request for the apparatus from a source network node;

transmitting, by the processor, a mobility acknowledgement to the source network node; and

receiving, by the processor, a complete message from the apparatus, wherein the complete message indicates that the apparatus has switched from the source network node to the target network node.
The method of Claim 19, further comprising:

receiving, by the processor, a physical random access channel (PRACH) signal from the apparatus; and

transmitting, by the processor, a timing advance (TA) value associated with the target network node to the apparatus or the source network node before the reception of the RRC complete message, wherein the TA value is determined based on the PRACH signal.