WO2021179112A1

WO2021179112A1 - Cyclic prefix extension adjustment for uplink communications

Info

Publication number: WO2021179112A1
Application number: PCT/CN2020/078382
Authority: WO
Inventors: Changlong Xu; Jing Sun; Xiaoxia Zhang
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2020-03-09
Filing date: 2020-03-09
Publication date: 2021-09-16
Anticipated expiration: 2022-09-09

Abstract

Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may maintain a gap prior to an uplink transmission to a base station based on a cyclic prefix (CP) extension. The base station may identify a timing advance (TA) of the UE and the base station may use the TA knowledge maintained at the base station to determine configuration parameters for the UE to use to determine the CP extension. The UE may receive the configuration parameters from the base station and may determine the CP extension based on the configuration parameters and the TA knowledge maintained at the UE. The TA knowledge at the base station may deviate from the TA knowledge at the UE over time, and the UE may assist the base station in maintaining TA synchronization between the base station the UE by providing CP information to the base station.

Description

CYCLIC PREFIX EXTENSION ADJUSTMENT FOR UPLINK COMMUNICATIONS

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to cyclic prefix extension adjustment for uplink communications.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal FDMA (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

In some wireless communications systems, a wireless device may perform a listen-before-talk (LBT) procedure prior to a transmission to another wireless device to ensure that a channel carrying the transmission is clear of other, potentially interfering transmissions. A time gap may be present prior to the transmission from the wireless device to provide time for performing the LBT procedure. In some cases, the wireless device may maintain the time gap with a cyclic prefix (CP) , which may be based on a timing advance (TA) at the wireless device. Over time, however, the TA may become inaccurate, which may result in erroneous LBT procedures and communication failures.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support cyclic prefix (CP) extension adjustment for uplink communications. Generally, the described techniques provide for maintaining accurate and consistent timing knowledge at a base station and a user equipment (UE) to support reliable communications that employ a listen-before-talk (LBT) gap for an LBT procedure. In some aspects, the UE may maintain an LBT gap (e.g., a time gap) by an extended CP for transmissions from the UE to the base station. In some cases, the UE may determine a CP extension based on a CP configuration received from the base station. For example, the base station may transmit a CP configuration including a number of configuration parameters that the UE may use to determine the CP extension. In some cases, the base station may determine the configuration parameters based on a timing advance (TA) associated with the UE that is measured during an initial access procedure between the UE and the base station. The base station and the UE may maintain separate understandings of the TA and the base station may use the TA maintained at the base station when determining the configuration parameters. The UE may determine the CP extension based on the configuration parameters and the TA maintained at the UE.

In some cases, the TA may change over time from the initial measurement as the UE moves or changes location after the initial access procedure (e.g., as the distance or environmental conditions between the UE and the base station change) . Accordingly, the base station may adjust the TA via a TA adjustment command to maintain accuracy and synchronization of the TA between the base station and the UE. The TA adjustment command may, however, be unreliable as the UE may sometimes unsuccessfully receive the TA adjustment command, which may result in the base station using a different TA than the UE. Further, the base station may be unaware of the failed TA adjustment command and may likewise be unable to compensate for the missed adjustment in a subsequent TA adjustment command. This may result in the base station determining configuration parameters with a first TA and the UE determining the CP extension with the configuration parameters and a second TA different than the first TA. In some cases, this may result in an inaccurate CP extension and, likewise, an inaccurate LBT gap.

In some implementations of the present disclosure, the UE may assist the base station in maintaining accurate knowledge of the TA associated with the UE. In some examples, the UE may determine the CP extension based on the CP configuration (e.g., the configuration parameters included in the CP configuration) and may monitor the CP extension with respect to a threshold range. If the CP extension is within the threshold range the UE may assume that the configuration parameters provided by the base station are accurate (e.g., are based on the same or a sufficiently similar TA as the TA maintained by the UE) and that the CP extension is accurate. Likewise, if the UE determines that the CP extension exceeds or is outside of the threshold range (e.g., satisfies the threshold) , the UE may determine that the configuration parameters provided from the base station are inaccurate (e.g., based on a different TA than the TA maintained by the UE) and that the CP extension is inaccurate. Accordingly, the UE may transmit a report to the base station including timing information maintained or calculated at the UE. In some other examples, the UE may provide such a report in response to a message from the base station (e.g., a triggering message) requesting UE-maintained timing information. Additionally or alternatively the UE may transmit such a report based on a configuration to periodically transmit the report. In some aspects, the report may enable the base station to synchronize or calibrate the timing information of the base station with the timing information of the UE. Accordingly, the base station may transmit another CP configuration to the UE including updated configuration parameters based on the timing information provided by the UE, which the UE may use to determine an accurate CP extension and, likewise, an accurate LBT gap.

A method of wireless communications at a UE is described. The method may include receiving, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determining, based on the CP configuration, to report CP information of the UE to the base station, and transmitting a report to the base station that includes the CP information based on the determining.

An apparatus for wireless communications at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to report CP information of the UE to the base station, and transmit a report to the base station that includes the CP information based on the determining.

Another apparatus for wireless communications at a UE is described. The apparatus may include means for receiving, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determining, based on the CP configuration, to report CP information of the UE to the base station, and transmitting a report to the base station that includes the CP information based on the determining.

A non-transitory computer-readable medium storing code for wireless communications at a UE is described. The code may include instructions executable by a processor to receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to report CP information of the UE to the base station, and transmit a report to the base station that includes the CP information based on the determining.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE, determining that the CP extension satisfies a threshold, and transmitting the report based on determining that the CP extension satisfies the threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the threshold includes one symbol length or zero.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting one or more extension parameters in the report to the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE, and determining the one or more extension parameters based on a proximity of the CP extension to one symbol length or zero.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE, determining a second set of one or more configuration parameters based on the CP extension and a target CP duration, and transmitting the second set of one or more configuration parameters in the report to the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the second set of one or more configuration parameters via a medium access control (MAC) control element (MAC-CE) .

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a configuration from the base station that indicates periodic reporting of the CP information at the UE, and periodically transmitting the report based on the configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a message from the base station that triggers reporting of the CP information at the UE, and transmitting the report based on the message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a TA of the UE in the report to the base station.

A method of wireless communications at a UE is described. The method may include receiving, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determining, based on the CP configuration, to transmit a random access channel (RACH) signal to the base station, and transmitting the RACH signal to the base station that indicates a TA of the UE based on the determining.

An apparatus for wireless communications at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to transmit a RACH signal to the base station, and transmit the RACH signal to the base station that indicates a TA of the UE based on the determining.

Another apparatus for wireless communications at a UE is described. The apparatus may include means for receiving, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determining, based on the CP configuration, to transmit a RACH signal to the base station, and transmitting the RACH signal to the base station that indicates a TA of the UE based on the determining.

A non-transitory computer-readable medium storing code for wireless communications at a UE is described. The code may include instructions executable by a processor to receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to transmit a RACH signal to the base station, and transmit the RACH signal to the base station that indicates a TA of the UE based on the determining.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CP extension based on one or more configuration parameters of the CP configuration and the TA of the UE, determining that the CP extension satisfies a threshold, and transmitting the RACH signal based on determining that the CP extension satisfies the threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CP extension based on one or more configuration parameters of the CP configuration and the TA of the UE, and transmitting the RACH signal indicating modification of the CP configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a second CP configuration from the base station based on the RACH signal, where the second CP configuration includes at least one configuration parameter different from the CP configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a message from the base station that triggers transmission of the RACH signal by the UE, and transmitting the RACH signal in response to the message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for periodically transmitting the RACH signal based on the message indicating periodic transmission of the RACH signal by the UE.

A method of wireless communications at a base station is described. The method may include transmitting, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, receiving, from the UE, an indication to modify one or more configuration parameters of the CP configuration, modifying the one or more configuration parameters based on the indication, and transmitting, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

An apparatus for wireless communications at a base station is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration, modify the one or more configuration parameters based on the indication, and transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

Another apparatus for wireless communications at a base station is described. The apparatus may include means for transmitting, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, receiving, from the UE, an indication to modify one or more configuration parameters of the CP configuration, modifying the one or more configuration parameters based on the indication, and transmitting, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

A non-transitory computer-readable medium storing code for wireless communications at a base station is described. The code may include instructions executable by a processor to transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration, modify the one or more configuration parameters based on the indication, and transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication may include operations, features, means, or instructions for receiving a report indicating that a CP extension at the UE satisfies a threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication may include operations, features, means, or instructions for receiving a report indicating at least one configuration parameter for a CP extension of the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for modifying the one or more configuration parameters according to the at least one configuration parameter, where the second CP configuration includes the at least one configuration parameter.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a report indicating a TA of the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for modifying the one or more configuration parameters based on the TA.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a RACH signal indicating a TA of the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a process flow that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a process flow that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIGs. 5 and 6 show block diagrams of devices that support cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 7 shows a block diagram of a communications manager that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 8 shows a diagram of a system including a device that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIGs. 9 and 10 show block diagrams of devices that support cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 11 shows a block diagram of a communications manager that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIG. 12 shows a diagram of a system including a device that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

FIGs. 13 through 20 show flowcharts illustrating methods that support cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

As demand for communication resources increases due to an increasing number of wireless devices communicating over the available spectrum, techniques to efficiently and reliably increase throughput are desirable. In some cases, a first device, such as a user equipment (UE) , may employ a listen-before-talk (LBT) procedure prior to a transmission to a second device, such as a base station, to ensure that a channel carrying the transmission is clear of other, potentially interfering transmissions. For example, a UE may perform an LBT procedure during a time gap between consecutive transmissions. To support an accurate LBT procedure, the UE and the base station may not transmit during the time gap, such that long time gaps may be associated with large overhead and reduced achievable throughput. As such, smaller time gaps that may comparatively increase throughput while maintaining the reliability of the LBT procedure may be desirable. In some cases, the UE may extend a cyclic prefix (CP) of a transmission to maintain a smaller time gap between transmissions.

In some cases, the base station may transmit a CP configuration including a number of configuration parameters that the UE may use to configure a CP extension of the uplink transmission. The base station may determine the configuration parameters based a timing advance (TA) associated with the UE (e.g., associated with a link between the base station and the UE) , which the base station and the UE may determine during an initial access procedure. In some aspects, upon completion of the initial access procedure, the base station and the UE may maintain separate knowledge of the TA. As the TA changes over time (e.g., as the UE changes location or as the environmental conditions of the link change since the initial access procedure) , the base station may transmit TA adjustment commands to the UE to maintain synchronization between the TA known to the UE and the TA known to the base station. However, the TA adjustment commands may be unreliable and, in some cases, the UE may fail to receive one or more of the TA adjustment commands. The base station may be unaware of the failed adjustments and may determine the configuration parameters for the UE to use to determine the CP extension based on a different TA than the TA known to the UE.

Various implementations of the present disclosure relate generally to efficiently and reliably maintaining accurate timing knowledge at the base station with assistance from the UE. In some implementations, the UE may transmit a report to the base station including timing information based on the TA maintained at the UE. For example, the base station may configure the UE to report timing information maintained at the UE to the base station such that the base station may synchronize the timing information of the base station and the timing information of the UE. In some examples, the UE may report the timing information maintained at the UE based on identifying that a determined CP extension for uplink transmissions to the base station satisfies a threshold. For example, if the UE determines that the CP extension of uplink transmissions deviates from a predefined range of allowable CP durations (or extension durations) , the UE may determine that the timing information maintained at the base station is out of synch with the timing information maintained at the UE. In some other examples, the UE may report the timing information maintained at the UE based on receiving signaling from the base station. For example, the base station may signal the UE to transmit the timing information maintained at the UE (e.g., the base station may transmit a message that triggers the UE to transmit the timing information of the UE) . Additionally or alternatively, the base station may signal the UE to periodically transmit the timing information maintained at the UE. For example, the base station may configure the UE to transmit the timing information maintained at the UE at pre-configured intervals.

In some further examples, the base station may re-synchronize the TA known to the base station and the TA known to the UE based on performing another access procedure (e.g., re-performing an initial access procedure) . For example, the base station may signal the UE to perform an access procedure, such as a random access procedure, when the base station determines that the timing information maintained at the base station is out of synch with the timing information maintained at the UE. In some aspects, the base station may determine that the timing information maintained at the base station is out of synch with the UE based on receiving an indication from the UE informing the base station of the desynchronization. In some examples, the UE may determine that the timing information maintained at the UE is out of synch with the base station based on identifying that the duration of the CP extension of uplink transmissions deviates from a predefined range of allowable CP durations or extension lengths. In such aspects, the base station may receive the indication and may transmit a message to the UE to trigger the UE to perform a new access procedure, which may enable the base station to re-measure the TA of the UE. In some other aspects, the base station may configure the UE to periodically trigger a new access procedure to enable the base station to re-measure TA at periodic intervals.

Particular aspects of the present disclosure may be implemented to realize one or more potential advantages. In some implementations, the described techniques may support accurate and consistent TA knowledge between a UE and a base station for a longer time period after an initial access procedure. Further, the UE and the base station may maintain consistent TA knowledge based on reliable signaling, which may enable a network implementing the described techniques to support shorter LBT gaps with higher reliability than networks implementing alternative TA adjustment methods. In some examples, the base station may configure the UE to assist the base station in TA adjustment determinations without excessive additional signaling, which may improve network reliability and efficiency while maintaining relatively low network overhead.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are additionally described in the context of process flows. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to cyclic prefix extension adjustment for uplink communications.

FIG. 1 illustrates an example of a wireless communications system 100 that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment) , as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) and may be positioned according to a channel raster for discovery by the UEs 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology) .

The communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz) ) . Devices of the wireless communications system 100 (e.g., the base stations 105, the UEs 115, or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time and communications for the UE 115 may be restricted to one or more active BWPs.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications) , or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115) . In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or with both.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

A base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations. For example, a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions. For example, the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115) . The UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS) , a channel state information reference signal (CSI-RS) ) , which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook) . Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115) may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal) . The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR) , or otherwise acceptable signal quality based on listening according to multiple beam directions) .

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

In some implementations of the present disclosure, a UE 115 may use a CP (e.g., an extended CP) of uplink transmissions to maintain a time gap between previous transmissions and the uplink transmissions. The time gap may enable the UE 115 to perform an LBT procedure and may be configured by a base station 105 to account for a TA of the UE 115. For example, the base station 105 may configure parameters for the UE to use to determine the CP extension of the uplink transmissions from the UE 115 such that the uplink transmissions are received at an expected time at the base station 105, while also using the extended CP to maintain the LBT gap.

To maintain accurate TA information at the base station 105, the base station 105 and the UE 115 may support UE-assisted TA maintenance procedures. For example, the base station 105 may configure the UE 115 to provide timing information maintained at the UE 115 based on one or more conditions. In some examples, the UE 115 may provide timing information associated with the CP of uplink transmissions from the UE 115 to the base station, which may be referred to as CP information. The CP information provided by the UE 115 may include one or more parameters that the UE 115 may use to determine the CP extension, such as CP configuration parameters, CP extension parameters, or the TA maintained at the UE 115. In some other examples, the base station 105 may configure the UE 115 to perform (or re-perform) an access procedure to enable the base station 105 to measure (or re-measure) the TA of the UE 115. For example, the base station 105 may transmit a message to the UE 115 that triggers the UE 115 to perform the access procedure. In some aspects, the access procedure may be a random access procedure and, accordingly, the UE 115 may transmit a random access channel (RACH) signal to the base station 105 based on receiving the message (e.g., the triggering message) . In such examples, the base station 105 may measure the TA of the UE 115 based on measuring the timing information associated with the RACH signal.

FIG. 2 illustrates an example of a wireless communications system 200 that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100. The wireless communication system 200 may include a UE 115-a and a base station 105-a, which may be examples of UEs 115 and base stations 105, respectively. The UE 115-a and the base station 105-a may communicate over a communication link 205. In some cases, the UE 115-a may be associated with a TA based on the communication link 205 (e.g., based on the distance of or the environmental conditions associated with the communication link 205) . The UE 115-a may apply the TA to uplink transmissions to the base station 105-a such that the base station 105-a may receive the uplink transmission in a subframe (e.g., an uplink subframe) aligned with another subframe (e.g., a downlink subframe) associated with the base station 105-a. For example, the UE 115-a may transmit an uplink transmission with the TA so that the base station 105-a receives the uplink transmission in an uplink subframe that is aligned in alignment or in synch with the base station 105-a.

In some cases, the UE 115-a may use the TA to determine an extension of a CP for uplink transmissions, which the UE 115-a may use to maintain an LBT gap prior to the uplink transmissions. In some examples, the UE 115-a and the base station 105-a may maintain separate knowledge of the TA and the wireless communication system 200 may support various UE-assisted TA maintenance procedures between the UE 115-a and the base station 105-a. Based on implementing a UE-assisted TA maintenance procedure, the UE 115-a and the base station 105-a may have a greater likelihood of maintaining synchronized TA knowledge.

The base station 105-a may measure the TA associated with the UE 115-a based on an initial access procedure, such as a random access procedure, between the UE 115-a and the base station 105-a. In some cases, the UE 115-a may attempt to connect to the base station 105-a in a contention-based or unlicensed frequency band. For example, the UE 115-a may attempt to connect to the base station 105-a via the random access procedure by transmitting a contention-based RACH signal 210, such as a physical RACH (PRACH) signal, to the base station 105-a. The base station may receive the RACH signal 210 and may determine the TA associated with the UE 115-a based on the RACH signal 210. For example, the base station 105-a may receive the RACH signal 210, estimate when the UE 115-a transmitted the RACH signal 210, and measure the difference (e.g., the time difference) between the estimated time that the UE 115-a transmitted the RACH signal 210 and when the base station 105-a received the RACH signal 210. Accordingly, the base station 105-a may determine the TA associated with the UE 115-a based on the measurement. The base station 105-a may transmit, as part of the random access procedure, a random access response to the UE 115-a including a TA command field including an indication of the measured TA.

The UE 115-a may store the measured TA and use the TA as a time offset for subsequent transmissions to the base station 105-a such that the base station 105-a may receive transmissions from the UE 115-a during expected time intervals. For instance, the UE 115-a may use the TA for transmissions to the base station 105-a so that the base station 105-a receives the transmission during an uplink subframe aligned with a downlink subframe of the base station 105-a. The UE 115-a may maintain the TA stored at the UE 115-a by updating the TA based on the movement and location of the UE 115-a. The base station 105-a may also attempt to maintain the TA associated with the UE 115-a at the base station 105-a by transmitting a TA adjustment command to the UE 115-a to synchronize the TA maintained at the UE 115-a with the TA maintained at the base station 105-a. The base station 105-a may use the TA maintained at the base station 105-a to determine a number of configuration parameters that the UE 115-a may use, in conjunction with the TA maintained at the UE 115-a, to determine a CP extension for uplink transmissions from the UE 115-a. In some aspects, the UE 115-a may use the determined CP extension to maintain a time gap between a previous transmission and a consecutive uplink transmission to the base station 105-a.

In some cases, the UE 115-a may employ the time gap between consecutive transmissions over the communication link 205 to perform an LBT procedure and, therefore, the time gap may be referred to as an LBT gap. The length (e.g., in the time domain) of the time gap may be based on the type of LBT (e.g., the category, or Cat, of LBT, such as Cat-1 LBT or Cat-2 LBT) . For example, for Cat-2 LBT an LBT gap of 16 microseconds (μs) or 25 μs may be used to increase the likelihood of an accurate (e.g., a proper) LBT procedure. The UE 115-a may use such LBT procedures between a number of different transmissions, including between a downlink transmission and an uplink transmission, between a first uplink transmission and a second uplink transmission, and between an uplink transmission and a downlink transmission, among other examples.

In some cases, the UE 115-a may use the CP extension, which may be between one symbol and zero (e.g., as defined in a specification) , to fully or partially maintain the LBT gap. The LBT gap may be located in one or more symbols preceding a transmission. For example, the LBT gap may be located in the one or more symbols immediately preceding the allocation of the transmission according to a start and length indicator value (SLIV) . The UE 115-a may extend an original or default CP duration based on the CP extension. In some cases, the UE 115-a may determine the CP extension based on one or more parameters and the type of LBT procedure that the UE 115-a uses. Table 1, as shown below, illustrates how a CP extension may be calculated at the UE 115-a based on the LBT type and the configuration parameters C1, C2, and C3.

b ₀b ₁	LBT Type	CP Extension
0	Cat-1 16μs	C2*symbol length –16μs –TA
1	Cat-2 25μs	C3*symbol length –25μs –TA
2	Cat-2 25μs	C1*symbol length –25μs –TA
3	Cat-4	0

Table 1: LBT Type and CP Extension

As illustrated by Table 1, the CP extension for different LBT types may be calculated differently. For example, for a given LBT procedure, the UE 115-a may calculate a CP extension based on the configuration parameters C1, C2, or C3, the symbol length (e.g., which may be based on the subcarrier spacing (SCS) associated with the transmission) , the desired LBT gap (i.e., 25μs or 16μs) , and the TA associated with the UE 115-a. In some aspects, the values associated with configuration parameters C1, C2, and C3 may be understood by the UE 115-a and the base station 105-a as a nominal gap of a number of symbols between two consecutive transmissions. The UE 115-a may determine the CP extension such that, as measured by the base station 105-a, the time gap between two consecutive transmissions corresponds to the LBT gap defined for each LBT type (e.g., 16μs or 25μs) . In some aspects, the UE 115-a may implement multiple LBT types simultaneously or may otherwise simultaneously store CP extensions associated with multiple LBT types. For example, the UE 115-a may use a first LBT type for a first type of communication or communications over a first channel and may use a second LBT type for a second type of communication or communications over a second channel. As such, the UE 115-a may be configured with values for one or more of C1, C2, and C3.

In some cases, C1 may be equal to 1 for some SCSs (e.g., when the SCS of the transmission is 15 kHz or 30 kHz) and equal to 2 for some other SCSs (e.g., when the SCS of the transmission is 60 kHz) . The base station 105-a may configure (e.g., dynamically configure) C2 and C3 for the UE 115-a. For example, the base station 105-a may transmit an indication of the values for C2 and C3 via control signaling, such as RRC signaling, to the UE 115-a in a CP configuration 215. In some cases, the base station 105-a may configure C2 and C3 specifically for the UE 115-a. For instance, the base station 105-a may determine the configuration parameters C2 and C3 based on the unique TA associated with the UE 115-a. As such, the base station 105-a may configure a different UE 115-a that is associated with a different TA with a different C2 and C3.

The base station 105-a may configure each of C2 and C3 to a value within a range of values based on the SCS (e.g., as defined in a specification) . For example, for some SCSs (e.g., 15 kHz SCS and 30 kHz SCS) , the base station 105-a may configure each of C2 and C3 to be a value within a first range of values (e.g., within a range of integer values including 1–28) and for some other SCSs (e.g., 60 kHz SCS) the base station 105-a may configure each of C2 and C3 to be a value within a second range of values (e.g., within a range of integer values including 2–28) . In some cases, the base station 105-a may explicitly indicate (e.g., via RRC signaling) values for C2 and C3 to the UE 115-a in the CP configuration 215. In some other cases, the UE 115-a may be configured with the first range of values and the second range of values and the base station 105-a may signal a number of index values (e.g., two index values) to the UE 115-a in the CP configuration 215 to indicate which value of the first range of values or the second range of values that the UE 115-a may use for C2 and C3 from the values configured at the UE 115-a.

In some cases, based on the determined CP extension, a processing timeline associated with the delay between a grant and a corresponding transmission (e.g., the delay between an uplink grant and a corresponding transmission on an uplink channel, such as a physical uplink shared channel (PUSCH) ) may be relaxed. For example, the processing timeline may be relaxed to account for (e.g., incorporate or allocate additional time for) the CP extension. For instance, an N2 timeline may be relaxed to account for the CP extension as determined by the UE 115-a.

Additionally, each LBT type, and corresponding CP extension, may be associated with a bit value associated with b ₀b ₁. For example, b ₀b ₁ may correspond to two bits and may include bit values of 0 (i.e., b ₀b ₁=00) , 1 (i.e., b ₀b ₁=01) , 2 (i.e., b ₀b ₁=10) , and 3 (i.e., b ₀b ₁=11) . For instance, b ₀b ₁ may be a two bit field that may be associated with an entry into Table 1. As such, the UE 115-a may associate a value of b ₀b ₁ to an LBT type and a CP extension. In some cases, the UE 115-a may use Table 1 for downlink grants (e.g., fallback downlink grants) and uplink grants (e.g., fallback uplink grants) .

In some cases, an indication of the LBT channel access priority class (CAPC) may be absent from Table 1. In some cases, the UE 115-a may determine the LBT CAPC based on the grant type. For example, for uplink grants where the base station 105-a initiates channel occupancy (e.g., initiates a channel occupancy time (COT) ) , the UE 115-a may determine (e.g., assume) that the base station 105-a uses an LBT CAPC value of 4 to acquire the channel occupancy. In cases when the UE 115-a initiates the channel occupancy (e.g., the COT) , such as in a Cat-4 LBT, the UE 115-a may select the LBT CAPC absent of any signaling or configuration from the base station 105-a. For instance, the UE 115-a may select the CAPC based on a mapping between priority classes and traffic classes. In some cases, the mapping may follow the same mechanism (e.g., the same mapping) as uplink carrier group transmissions (e.g., as defined in a specification) . For downlink grants (e.g., for uplink control channels, such as physical uplink control channels (PUCCHs) associated with a downlink grant) , the UE 115-a may determine to select the highest priority LBT CAPC for some LBT types (e.g., for Cat-4 LBT) .

The base station 105-a may configure C2 and C3 to different (e.g., additional) values via RRC configuration for UE to calculate the CP extension. For example, the possible supported range of values for C2 and C3 may include values within a range of values including 1–28 for some SCSs (e.g., 15 kHz SCS and 30 kHz SCS) . The possible supported range of values for C2 and C3 may include values within a range of values including 2–28 for other SCSs (e.g., 60 kHz SCS) . As described herein, the base station 105-a may configure the values of C2 and C3 based on the TA associated with the UE 115-a.

In some cases, the UE 115-a and the base station 105-a may use either Cat-1 16μs or Cat-2 25μs when the communication between the UE 115-a and the base station 105-a includes a downlink transmission followed by an uplink transmission. As such, the UE 115-a may determine a CP extension based on either C2*symbol length –16μs –TA or C3*symbol length –25μs –TA for Cat-1 16μs or Cat-2 25μs, respectively. In some aspects, the UE 115-a may determine the CP extension such that, as measured from the base station 105-a, the time gap between the downlink transmission ending and the uplink transmission arriving is either 16μs for Cat-1 16μs and 25μs for Cat-2 25μs. For instance, the UE 115-a may use a CP extension to maintain the LBT gap between the downlink transmission and the uplink transmission.

The base station 105-a may configure the values for C2 or C3, which the UE 115-a may use to determine the CP extension, based on the TA associated with the UE 115-a maintained at the base station 105-a, and may transmit C2 or C3 (e.g., may transmit one or both of C2 or C3) to the UE 115-a in a CP configuration 215. In some cases, however, the base station 105-a may maintain a different TA than the UE 115-a, which may result in values for C2 or C3 that are inconsistent with the TA maintained at the UE 115-a and, likewise, may result in an inaccurate CP extension determination. For example, as described herein, the base station 105-a may measure the TA associated with the UE 115-a based on an estimated transmission time of the RACH signal 210 and the time at which the base station 105-a receives the RACH signal 210. The base station 105-a may transmit an indication of the TA to the UE 115-a and the UE 115-a may apply the TA for a subsequent time period (e.g., for a number of subsequent uplink transmissions) . However, the UE 115-a may change location (e.g., distance from the base station 105-a) or orientation, or both, which may alter the actual TA associated with the UE 115-a from the TA maintained at the base station 105-a.

To update the TA at the base station 105-a to account for movement of the UE 115-a, the base station 105-a may transmit a number of TA adjustment commands to adjust the arrival time of uplink transmissions from the UE 115-a. However, such TA adjustment commands may be unreliable (e.g., may miss or may otherwise be unsuccessfully received by the UE 115-a) such that, over time, the base station 105-a may lose the absolute TA associated with the UE 115-a. For example, the base station 105-a may attempt to preserve the accuracy of the TA maintained at the base station 105-a by accumulating the number of TA adjustment commands, but because some of the TA adjustment commands may have missed the UE 115-a, the timing of the uplink transmissions from the UE 115-a may not include all of the TA adjustment commands and, therefore, the UE 115-a and the base station 105-a may become out of synch in their respective knowledge of the TA. For instance, TA adjustment commands that are unsuccessfully received by the UE 115-a, and therefore not incorporated in the TA used by the UE 115-a, may nonetheless be accounted for by the base station 105-a as errors that deviate the TA maintained by the base station 105-a from the TA maintained by the UE 115-a.

Accordingly, the base station 105-a may provide values for C2 or C3 based on a different TA than the TA that the UE 115-a will use to determine the CP extension for an uplink transmission (as defined in Table 1) . Because the UE 115-a may maintain the LBT gap based on the CP extension, such inconsistency in the determination of the CP extension may result in inaccurate LBT gaps (e.g., erroneous LBT procedures) as well as misaligned uplink transmissions.

In some examples of the present disclosure, the UE 115-a may assist the base station 105-a to determine C2 or C3 values based on sharing the timing information (e.g., the CP information) maintained or calculated by the UE 115-a with the base station 105-a. In this manner, the base station 105-a may configure UE-specific C2 or C3 values based on the TA associated with the UE 115-a and the CP information provided by the UE 115-a. In some examples, the UE 115-a may transmit the CP information of the UE 115-a to the base station 105-a in a report 225. In some implementations, the report 225 may be based on a layer 3 (L3) measurement. In some other implementations, UE 115-a may transmit the report 225 in a MAC control element (MAC-CE) .

The UE 115-a may transmit the report 225 based on one or more triggering conditions. In some examples, a triggering condition may be configured at the UE 115-a by the base station 105-a or may be preconfigured at the UE 115-a. For example, the UE 115-a may monitor the CP extension duration and may be configured to transmit the report 225 based on determining that the CP extension duration satisfies a threshold. In some other examples, a triggering condition may include receiving one or more signals from the base station 105-a. For example, the base station 105-a may transmit a message, such as a triggering message 220, to the UE 115-a that may cause (i.e., trigger) the UE 115-a to transmit the report 225 to the base station 105-a. Additionally or alternatively, the UE 115-a may be configured to periodically transmit the report 225. For example, in some implementations, the base station 105-a may configure the UE 115 to transmit the report 225 based on a defined time period or time interval. For instance, the UE 115-a may transmit the report 225 based on a periodicity configured by the base station 105-a. Additional details of the report 225 are described with reference to FIG. 3.

In some other implementations, the base station 105-a may configure the UE 115-a to perform an access procedure to enable the base station 105-a to measure the TA of the UE 115-a. In some examples, the base station 105-a may configure the UE 115-a to re-perform a random access procedure by transmitting another RACH signal 210 to the base station 105-a. In such examples, the base station 105-a may receive the RACH signal 210 and measure the TA associated with the UE 115-a based on receiving the RACH signal 210. As such, the UE 115-a and the base station 105-a may perform similar steps as described in the context of the random access procedure performed during the initial access of the UE 115-a to the base station 105-a. In some examples, based on the already established connection between the UE 115-a and the base station 105-a, the base station 105-a may configure the UE 115-a to transmit a contention-free random access RACH signal 210 such that the base station 105-a may re-measure the TA associated with the UE without the UE 115-a risking a loss of access to the base station 105-a, which may potentially occur in the case that the UE 115-a transmits contention based random access RACH signal 210. Additional details of a second RACH signal 210 (e.g., a contention-free random access RACH signal 210) are described with reference to FIG. 4.

FIG. 3 illustrates an example of a process flow 300 that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure. In some examples, process flow 300 may implement aspects of

wireless communications systems

100 or 200. Process flow 300 may include a UE 115-b and a base station 105-b, which may be examples of corresponding devices as described herein. Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.

At 305, the base station 105-b may transmit, to the UE 115-b, a CP configuration for extension of a CP for uplink transmissions by the UE 115-b. In some examples, the CP configuration may include one or more configuration parameters for the UE 115-b to use to determine the CP extension, as described in more detail with reference to FIG. 2. For example, the base station 105-b may determine the configuration parameters (e.g., C2 or C3) based on a TA associated with the UE 115-b and may transmit the configuration parameters to the UE 115-b in the CP configuration. In some aspects, the base station 105-b may transmit the CP configuration to the UE 115-b via control signaling, such as RRC signaling. In some cases, the base station 105-b may measure the TA associated with the UE 115-b based on an access procedure, such as a random access procedure, as described in more detail with reference to FIGs. 2 and 4.

At 310, the UE 115-b may determine a CP extension based on the configuration parameters of the CP configuration and the TA of the UE 115-b. In some examples, the UE 115-b may determine the CP extension based on the configuration parameters C2 or C3 received from the base station 105-b and the TA of the UE 115-b that is maintained at the UE 115-b (e.g., the UE 115-b may know the TA for uplink transmissions based on the location or orientation of the UE 115-b relative to the base station 105-b) . In some examples, the UE 115-b may use the CP extension to maintain an LBT gap before uplink transmissions from the UE 115-b and, accordingly, may determine the CP extension based on the one or more LBT types implemented by the UE 115-b. For example, the UE 115-b may determine the CP extension based on Table 1, as described in more detail with reference to FIG. 2.

At 315, the UE 115-b may, in some implementations, determine that the CP extension satisfies a threshold. For example, the base station 105-b may configure the UE 115-b to monitor the CP extension determined by the UE 115-b at 310 with respect to the threshold (e.g., a preconfigured or a dynamically configured threshold) . In some examples, the UE 115-b may be configured to transmit a report including CP information of the UE 115-b upon determining that the CP extension satisfied the threshold. For example, if the UE 115-b determines that the determined CP extension satisfies the threshold, the UE 115-b may determine that the TA knowledge of the base station 105-b may be out of synch with the TA knowledge maintained at the UE 115-b.

In some implementations, the UE 115-b may support CP extensions with lengths (e.g., in the time domain) within a range of time durations. For example, the UE 115-b may support CP extensions with lengths between one symbol length (e.g., one OFDM symbol length) and zero and may refrain from using CP extensions with lengths greater than one symbol length or less than zero. As such, the threshold may be either one symbol length or zero, or, in some cases, a value proximate to either one symbol length or zero, which may provide a buffer before the CP extension caps (e.g., the threshold may be 0.95× one symbol length or 0.05×one symbol length) . For example, in the case of a Cat-1 16μs LBT type, the UE 115-b may determine a CP extension T2, where T2 = C2×symbol length –16μs –TA. In such cases, the UE 115-b may determine that the CP extension satisfies the threshold if T2 reaches (or nears within a defined proximity) one symbol length or zero. Similarly, in the case of a Cat-2 25 μs LBT type, the UE 115-b may determine a CP extension T3, where T3 = C3×symbol length –25μs –TA. In such cases, the UE 115-b may determine that the CP extension satisfies the threshold if T3 reaches (or nears within a defined proximity) one symbol length or zero.

At 320, the base station 105-b may, in some implementations, transmit a message to the UE 115-a that triggers reporting of the CP information of the UE 115-b. In some examples, the message may be referred to as a triggering message and the base station 105-b may transmit the triggering message based on a number of different conditions, such as based on a determination that the TA maintained at the base station 105-b is out of synch with the TA maintained at the UE 115-b, receiving an indication from the UE 115-b, or an expiration of a timer associated with the validity of the TA of the UE 115-b.

At 325, the base station 105-b may, in some implementations, transmit a configuration that indicates periodic reporting of the CP information of the UE 115-b to the base station 105-b. In some examples, the configuration may be referred to as a periodic configuration and the base station 105-b may configure the UE 115-b to transmit a report including the CP information at the UE 115-b according to a defined periodicity, which may ensure consistent TA knowledge between the UE 115-b and the base station 105-b without additional signaling overhead.

At 330, the UE 115-b may, in some implementations, determine a second set of one or more configuration parameters based on the CP extension and a target CP duration. For example, the UE 115-b may calculate a value for C2 or C3 (e.g., a UE-recommended value for C2 or C3) such that the corresponding CP extension T2 or T3 is the target CP duration (e.g., a CP duration within the range of CP extensions supported by the UE 115-b) . In some examples, the UE 115-b may calculate recommended values for C2 or C3 when the determined CP extension T2 or T3 satisfies the threshold at 315. In some other examples, the UE 115-b may calculate desired values for C2 or C3 based on criteria other than the determined CP extension T2 or T3 satisfying the threshold.

The operations performed at 315, 320, 325, and 330 may each be associated with triggering conditions at the UE 115-b and may be performed or occur in addition or alternatively to each other. For example, the operations performed at 315, 320, 325, and 330 may each be performed in separate embodiments of the present disclosure or may be performed together in any combination.

At 335, the UE 115-b may transmit a report to the base station 105-b that includes the CP information. The UE 115-b may determine to transmit the report based on determining that the CP extension satisfies the threshold at 315, receiving the triggering message at 320, receiving the periodic configuration at 325, or determining the second set of configuration parameters at 330, or based on any combination thereof. In some implementations, the UE 115-b may transmit the report to the base station 105-b based on an L3 measurement or in a MAC-CE. In some examples, the parameters included within the CP information transmitted to the base station 105-b may be based on the triggering condition.

For example, in implementations where the UE 115-b determines that the CP extension satisfies the threshold (e.g., reaches, or nears within a defined proximity, one symbol length or zero) , the UE 115-b may transmit one or more extension parameters in the report to the base station 105-b. In some examples, the UE 115-b may determine the extension parameters based on the proximity of the CP extension to the threshold (e.g., the proximity of the CP extension to either one symbol length or zero) . In some aspects, the extension parameters may be the bits b ₀b ₁.

In some examples, the UE 115-b may determine the CP extension based on the configuration parameters C2 or C3 and the TA maintained at the UE 115-b and determine values for b ₀ or b ₁, depending on if the implemented LBT type is Cat-1 16μs or Cat-2 25μs, respectively, based on the proximity of the CP extension T2 or T3 to one symbol length or zero. For example, if the UE 115-b employs a Cat-1 16μs LBT type and determines that T2 is close (e.g., proximate or within a threshold value) to zero, the UE 115-b may determine that b ₀=0. Alternatively, if the UE 115-b similarly employs a Cat-1 16μs LBT type but determines that T2 is close (e.g., proximate or within a threshold value) to one symbol length, the UE 115-b may determine that b ₀=1. In the case that the UE 115-b employs a Cat-2 25μs LBT type, the UE 115-b may similarly determine that b ₁=0 if T3 is close (e.g., proximate or within a threshold value) to 0 and determine that b ₁=1 if T3 is close (e.g., proximate or within a threshold value) to 1.

The UE 115-b may report values for b ₀b ₁ via an explicit indication to the base station 105-b or by transmitting a parameter associated with the value of b ₀b ₁ to the base station 105-b. For example, the UE 115-b may select a parameter from Table 2, as shown below, that may correspond to a value of b ₀b ₁ (e.g., a two bit field) .

Table 2: Parameter Value and b ₀b ₁

For example, the UE 115-b or the base station 105-b, or both, may associate different parameter values to different values of the b ₀b ₁ bit field. For instance, a parameter value of 1 may be associated with b ₀b ₁=00, a parameter value of 2 may be associated with b ₀b ₁=01, a parameter value of 3 may be associated with b ₀b ₁=10, and a parameter value of 4 may be associated with b ₀b ₁=11.

Additionally or alternatively, the UE 115-b may directly report values for C2 or C3 in the report to the base station 105-b. In some examples, the UE 115-b may report the values for C2 or C3 calculated at 330 (e.g., the UE-recommended values for C2 or C3) . In some aspects, the UE 115-b may indicate the values for C2 or C3 via a number of bits (e.g., 5 bits each and 10 bits total) . Additionally or alternatively, the UE 115-b may directly transmit the TA maintained at the UE 115-b to the base station 105-b. In some further additional or alternative examples, the UE 115-b may include any other information relevant to the timing information or the CP information of the UE 115-b in the report to the base station 105-b.

At 340, the base station 105-b may modify one or more configuration parameters based on receiving the report (e.g., an indication from the UE 115-b) . In some examples, the base station 105-b may modify the configuration parameters (e.g., C2 or C3) based on the CP information received from the UE 115-b in the report. For example, in implementations where the UE 115-b transmits extension parameters (e.g., b ₀ or b ₁) the base station 105-b may adjust the values of the configuration parameters based on the values of the extension parameters determined by the UE 115-b. For instance, the base station 105-b may increase C2 if b ₀=0 and may decrease C2 if b ₀=1. Similarly, the base station 105-b may increase C3 if b ₁=0 and may decrease C3 if b ₁=1. Additionally or alternatively, in implementations where the UE 115-b includes UE-recommended configuration parameters to the base station 105-b, the base station 105-b may modify the configuration parameters to match the UE-recommended configuration parameters. In some examples, the base station 105-b may use the modified configuration parameters to update the TA maintained at the base station 105-b.

At 345, the base station 105-b may transmit a second CP configuration for extension of the CP for uplink transmissions by the UE 115-b, the second CP configuration including the modified configuration parameters. In some examples, the base station 105-b may transmit the second CP configuration via control signaling, such as RRC signaling. The UE 115-b may receive the second CP configuration and, accordingly, use the modified configuration parameters to determine CP extensions for subsequent uplink transmissions to the base station 105-b. As such, the UE 115-b may use an extended CP duration prior to uplink transmissions to the base station 105-b that maintain the LBT gap for an LBT procedure by the UE 115-b and align the uplink transmission so that the base station 105-b may receive the uplink transmission in an uplink subframe aligned with other subframes associated with the base station 105-b (e.g., such as a downlink subframe that the base station 105-b may have used to transmit a previous downlink transmission to the UE 115-b) .

FIG. 4 illustrates an example of a process flow 400 that supports cyclic prefix extension adjustment for uplink communications in accordance with aspects of the present disclosure. In some examples, process flow 400 may implement aspects of wireless communications system 100 and wireless communications system 200. Process flow 400 may include a UE 115-c and a base station 105-c, which may be examples of corresponding devices as described herein. Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.

At 405, the base station 105-c may transmit, to the UE 115-c, a CP configuration for extension of a CP for uplink transmissions by the UE 115-c. In some examples, the CP configuration may include one or more configuration parameters for the UE 115-c to use to determine the CP extension, as described in more detail with reference to FIG. 2. For example, the base station 105-c may determine the configuration parameters (e.g., C2 or C3) based on a TA associated with the UE 115-c and may transmit the configuration parameters to the UE 115-c in the CP configuration. In some aspects, the base station 105-c may transmit the CP configuration to the UE 115-c via control signaling, such as RRC signaling. In some cases, the base station 105-c may measure the TA associated with the UE 115-c based on an access procedure, such as a random access procedure.

At 410, the UE 115-c may determine a CP extension based on the configuration parameters of the CP configuration and the TA of the UE 115-c. In some examples, the UE 115-c may determine the CP extension based on the configuration parameters C2 or C3 received from the base station 105-c and the TA of the UE 115-c that is maintained at the UE 115-c. In some examples, the UE 115-c may use the CP extension to maintain an LBT gap before uplink transmissions from the UE 115-c and, accordingly, may determine the CP extension based on the one or more LBT types implemented by the UE 115-c. For example, the UE 115-c may determine the CP extension based on Table 1, as described in more detail with reference to FIG. 2.

At 415, the UE 115-c may, in some implementations, determine that the CP extension satisfies a threshold. For example, the base station 105-c may configure the UE 115-c to monitor the CP extension determined by the UE 115-c at 410 with respect to the threshold (e.g., a preconfigured or a dynamically configured threshold) . In some examples, the UE 115-c may be configured to transmit a RACH signal upon determining that the CP extension satisfies the threshold. For example, if the UE 115-c determines that the determined CP extension satisfies the threshold, the UE 115-c may determine that the configuration parameters configured by the base station 105-c may be out of synch with the timing information maintained at the UE 115-c. The UE 115-c may determine whether the CP extension satisfies the threshold in a similar manner as described at 315 with reference to FIG. 3.

At 420, the base station 105-c may, in some implementations, transmit a message to the UE 115-c that triggers transmission of the RACH signal by the UE 115-c. In some examples, the message may be referred to as a triggering message and the UE 115-c may transmit the RACH signal in response to receiving the message. In some aspects, the base station 105-c may transmit the message at 420 in response to receiving an indication from the UE 115-c indicating that the timing information maintained at the UE 115-c may be out of synch with the timing information maintained at the base station 105-c (e.g., the UE 115-c may indicate to the base station 105-c that the configuration parameters may be re-configured to maintain accurate LBT gaps) . In some examples, the UE 115-c may transmit the indication based on determining that the CP extension satisfies the threshold. In some other examples, the UE 115-c may transmit the indication based on a number of other reasons.

In some additional examples, the message may include an indication that the UE 115-c may periodically transmit the RACH signal. For example, the base station 105-c, via the message, may configure the UE 115-c to transmit the RACH signal according to a defined periodicity, which may allow for consistent or more accurate TA knowledge between the UE 115-c and the base station 105-c without additional signaling overhead.

At 425, the UE 115-c may transmit the RACH signal to the base station 105-c. In some implementations, the base station 105-c may use the RACH signal to measure the TA of the UE 115-c (e.g., the RACH signal may indicate a TA of the UE 115-c) and to update the timing information stored at the UE 115-c based on the measured TA (e.g., an absolute TA measurement) . In some examples, the UE 115-c may transmit the RACH signal based on determining that the CP extension satisfies the threshold at 415 or based on receiving the message (e.g., the triggering message) at 420, or both.

The UE 115-c may transmit the RACH signal as part of re-performing a random access procedure to enable the base station 105-c to synchronize with the UE 115-c based on re-measuring the TA of the UE 115-c. Accordingly, the base station may reply to the RACH signal with a random access response, which may include a TA command field including an indication of the measured TA of the UE 115-c. In some examples, because the UE 115-c is already connected to the base station 105-c, the UE 115-c may perform a contention-free random access procedure and transmit a contention-free random access RACH signal. For example, the UE 115-c may transmit the RACH signal over a contention-free band (e.g., a contention-free radio frequency spectrum band) . Accordingly, the UE 115-c may avoid risking a loss of access or connection to the base station 105-c, as opposed to the potential risk of losing access or connection to the base station 105-c that the UE 115-c may experience when transmitting a contention-based random access RACH signal (e.g., the RACH signal transmitted when initially connecting to the base station 105-c) .

At 430, the base station 105-c may modify one or more configuration parameters based on the indication of the TA. In some examples, the receiving the indication of the TA may be associated with measuring the TA based on receiving the RACH signal at 425. The base station 105-c may modify the configuration parameters based on the measured (or re-measured) TA.

At 435, the base station 105-c may transmit, to the UE 115-c, a second CP configuration for extension of the CP for uplink transmissions by the UE 115-c. In some examples, the second CP configuration may include the modified configuration parameters. In some aspects, the base station 105-c may transmit the second CP configuration via control signaling, such as RRC signaling. The UE 115-c may receive the second CP configuration and, accordingly, use the modified configuration parameters to determine CP extensions for subsequent uplink transmissions to the base station 105-c. As such, the UE 115-c may use an extended CP duration prior to uplink transmissions to the base station 105-c that maintain the LBT gap for an LBT procedure by the UE 115-c and align the uplink transmission so that the base station 105-c may receive the uplink transmission in an uplink subframe aligned with other subframes associated with the base station 105-c (e.g., such as the downlink subframe that the base station 105-c may have used to transmit a previous downlink transmission to the UE 115-c) .

FIG. 5 shows a block diagram 500 of a device 505 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CP extension adjustment for uplink communications, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to report CP information of the UE to the base station, and transmit a report to the base station that includes the CP information based on the determining. The communications manager 515 may also receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to transmit a RACH signal to the base station, and transmit the RACH signal to the base station that indicates a TA of the UE based on the determining. The communications manager 515 may be an example of aspects of the communications manager 810 described herein.

The communications manager 515, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 515, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 515, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 515, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 515, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 520 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 520 may utilize a single antenna or a set of antennas.

In some examples, the communications manager 515 may be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 510 and transmitter 520 may be implemented as analog components (e.g., amplifiers, filters, antennas) coupled with the mobile device modem to enable wireless transmission and reception over one or more bands.

The communications manager 515 as described herein may be implemented to realize one or more potential advantages. One implementation may allow the device 505 to provide assistance for maintaining synchronization of TA knowledge between the device 505 and a base station. Based on the techniques for maintaining synchronization of TA knowledge between the device 505 and the base station, the device 505 may support more accurate LBT gaps and, therefore, more accurate LBT procedures within the LBT gaps.

As such, the device 505 may increase the likelihood of accurately sensing the occupancy of a channel and, accordingly, may communicate over the channel with a greater likelihood of successful communications. In some examples, based on a greater likelihood of successful communications, the device 505 may more efficiently power a processor or one or more processing units associated with an LBT procedure and transmitting and receiving communications, which may enable the device to save power and increase batter life.

FIG. 6 shows a block diagram 600 of a device 605 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a device 505, or a UE 115 as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 640. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CP extension adjustment for uplink communications, etc. ) . Information may be passed on to other components of the device 605. The receiver 610 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 610 may utilize a single antenna or a set of antennas.

The communications manager 615 may be an example of aspects of the communications manager 515 as described herein. The communications manager 615 may include a configuration receiver 620, a determination component 625, a report transmitter 630, and a RACH transmitter 635. The communications manager 615 may be an example of aspects of the communications manager 810 described herein.

The configuration receiver 620 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The configuration receiver 620 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE.

The determination component 625 may determine, based on the CP configuration, to report CP information of the UE to the base station. The determination component 625 may determine, based on the CP configuration, to transmit a RACH signal to the base station.

The report transmitter 630 may transmit a report to the base station that includes the CP information based on the determining.

The RACH transmitter 635 may transmit the RACH signal to the base station that indicates a TA of the UE based on the determining.

The transmitter 640 may transmit signals generated by other components of the device 605. In some examples, the transmitter 640 may be collocated with a receiver 610 in a transceiver module. For example, the transmitter 640 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 640 may utilize a single antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a communications manager 705 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The communications manager 705 may be an example of aspects of a communications manager 515, a communications manager 615, or a communications manager 810 described herein. The communications manager 705 may include a configuration receiver 710, a determination component 715, a report transmitter 720, an extension manager 725, a threshold component 730, a parameter component 735, a message receiver 740, a TA component 745, and a RACH transmitter 750. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The configuration receiver 710 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE.

In some examples, the configuration receiver 710 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. In some examples, the configuration receiver 710 may receive a configuration from the base station that indicates periodic reporting of the CP information at the UE. In some examples, receiving a second CP configuration from the base station based on the RACH signal, where the second CP configuration includes at least one configuration parameter different from the CP configuration.

The determination component 715 may determine, based on the CP configuration, to report CP information of the UE to the base station. In some examples, the determination component 715 may determine, based on the CP configuration, to transmit a RACH signal to the base station.

The report transmitter 720 may transmit a report to the base station that includes the CP information based on the determining. In some examples, the report transmitter 720 may transmit the report based on determining that the CP extension satisfies the threshold. In some examples, the report transmitter 720 may transmit one or more extension parameters in the report to the base station.

In some examples, the report transmitter 720 may transmit the second set of one or more configuration parameters in the report to the base station. In some examples, the report transmitter 720 may transmit the second set of one or more configuration parameters via a MAC-CE. In some examples, the report transmitter 720 may periodically transmit the report based on the configuration. In some examples, the report transmitter 720 may transmit the report based on the message.

The extension manager 725 may determine a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE. In some examples, the extension manager 725 may determine a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE.

In some examples, the extension manager 725 may determine the one or more extension parameters based on a proximity of the CP extension to one symbol length or zero. In some examples, the extension manager 725 may determine a CP extension based on one or more configuration parameters of the CP configuration and the TA of the UE. In some examples, the extension manager 725 may determine a CP extension based on one or more configuration parameters of the CP configuration and the TA of the UE.

The threshold component 730 may determine that the CP extension satisfies a threshold. In some examples, the threshold component 730 may determine that the CP extension satisfies a threshold. In some cases, the threshold includes one symbol length or zero.

The parameter component 735 may determine a second set of one or more configuration parameters based on the CP extension and a target CP duration.

The message receiver 740 may receive a message from the base station that triggers reporting of the CP information at the UE. In some examples, the message receiver 740 may receive a message from the base station that triggers transmission of the RACH signal by the UE.

The TA component 745 may transmit a TA of the UE in the report to the base station.

The RACH transmitter 750 may transmit the RACH signal to the base station that indicates a TA of the UE based on the determining. In some examples, the RACH transmitter 750 may transmit the RACH signal based on determining that the CP extension satisfies the threshold. In some examples, the RACH transmitter 750 may transmit the RACH signal indicating modification of the CP configuration. In some examples, the RACH transmitter 750 may transmit the RACH signal in response to the message. In some examples, the RACH transmitter 750 may periodically transmit the RACH signal based on the message indicating periodic transmission of the RACH signal by the UE.

FIG. 8 shows a diagram of a system 800 including a device 805 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 805 may be an example of or include the components of device 505, device 605, or a UE 115 as described herein. The device 805 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 810, an I/O controller 815, a transceiver 820, an antenna 825, memory 830, and a processor 840. These components may be in electronic communication via one or more buses (e.g., bus 845) .

The communications manager 810 may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to report CP information of the UE to the base station, and transmit a report to the base station that includes the CP information based on the determining. The communications manager 810 may also receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE, determine, based on the CP configuration, to transmit a RACH signal to the base station, and transmit the RACH signal to the base station that indicates a TA of the UE based on the determining.

The I/O controller 815 may manage input and output signals for the device 805. The I/O controller 815 may also manage peripherals not integrated into the device 805. In some cases, the I/O controller 815 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 815 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 815 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 815 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I/O controller 815 or via hardware components controlled by the I/O controller 815.

The transceiver 820 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described herein. For example, the transceiver 820 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 820 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 825. However, in some cases the device may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 830 may include random-access memory (RAM) and read-only memory (ROM) . The memory 830 may store computer-readable, computer-executable code 835 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 830 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 840 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a central processing unit (CPU) , a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting CP extension adjustment for uplink communications) .

The code 835 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 835 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 9 shows a block diagram 900 of a device 905 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 905 may be an example of aspects of a base station 105 as described herein. The device 905 may include a receiver 910, a communications manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CP extension adjustment for uplink communications, etc. ) . Information may be passed on to other components of the device 905. The receiver 910 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The receiver 910 may utilize a single antenna or a set of antennas.

The communications manager 915 may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters, receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration, and modify the one or more configuration parameters based on the indication. The communications manager 915 may be an example of aspects of the communications manager 1210 described herein.

The communications manager 915, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 915, or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 915, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 915, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 915, or its sub-components, may be combined with one or more other hardware components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 920 may transmit signals generated by other components of the device 905. In some examples, the transmitter 920 may be collocated with a receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The transmitter 920 may utilize a single antenna or a set of antennas.

The communications manager 915 as described herein may be implemented to realize one or more potential advantages. One implementation may enable the device 905 to more accurately provide CP configuration parameters to a UE based on maintaining synchronization of TA knowledge between the device 905 and the UE, which may result in more accurate LBT procedures by the UE and a greater likelihood for uplink transmissions from the UE to be received at the device 905 during an expected time interval. Further, based the techniques described herein, the device 905 may provide for more consistent access between the device and a UE, which may result in fewer access procedures and reduce system interference.

FIG. 10 shows a block diagram 1000 of a device 1005 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 1005 may be an example of aspects of a device 905, or a base station 105 as described herein. The device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1035. The device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CP extension adjustment for uplink communications, etc. ) . Information may be passed on to other components of the device 1005. The receiver 1010 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The receiver 1010 may utilize a single antenna or a set of antennas.

The communications manager 1015 may be an example of aspects of the communications manager 915 as described herein. The communications manager 1015 may include a configuration transmitter 1020, an indication receiver 1025, and a modification component 1030. The communications manager 1015 may be an example of aspects of the communications manager 1210 described herein.

The configuration transmitter 1020 may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE and transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

The indication receiver 1025 may receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration.

The modification component 1030 may modify the one or more configuration parameters based on the indication.

The transmitter 1035 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1035 may be collocated with a receiver 1010 in a transceiver module. For example, the transmitter 1035 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The transmitter 1035 may utilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a communications manager 1105 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The communications manager 1105 may be an example of aspects of a communications manager 915, a communications manager 1015, or a communications manager 1210 described herein. The communications manager 1105 may include a configuration transmitter 1110, an indication receiver 1115, a modification component 1120, a report receiver 1125, and a RACH receiver 1130. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The configuration transmitter 1110 may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE. In some examples, the configuration transmitter 1110 may transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters.

The indication receiver 1115 may receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration.

The modification component 1120 may modify the one or more configuration parameters based on the indication. In some examples, the modification component 1120 may modify the one or more configuration parameters according to the at least one configuration parameter, where the second CP configuration includes the at least one configuration parameter. In some examples, the modification component 1120 may modify the one or more configuration parameters based on the TA.

The report receiver 1125 may receive a report indicating that a CP extension at the UE satisfies a threshold. In some examples, the report receiver 1125 may receive a report indicating at least one configuration parameter for a CP extension of the UE. In some examples, the report receiver 1125 may receive a report indicating a TA of the UE. In some cases, the threshold includes one symbol length or zero.

The RACH receiver 1130 may receive a RACH signal indicating a TA of the UE.

FIG. 12 shows a diagram of a system 1200 including a device 1205 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The device 1205 may be an example of or include the components of device 905, device 1005, or a base station 105 as described herein. The device 1205 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1210, a network communications manager 1215, a transceiver 1220, an antenna 1225, memory 1230, a processor 1240, and an inter-station communications manager 1245. These components may be in electronic communication via one or more buses (e.g., bus 1250) .

The communications manager 1210 may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE, transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters, receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration, and modify the one or more configuration parameters based on the indication.

The network communications manager 1215 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1215 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1220 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described herein. For example, the transceiver 1220 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1220 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1225. However, in some cases the device may have more than one antenna 1225, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1230 may include RAM, ROM, or a combination thereof. The memory 1230 may store computer-readable code 1235 including instructions that, when executed by a processor (e.g., the processor 1240) cause the device to perform various functions described herein. In some cases, the memory 1230 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1240 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1240 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1240. The processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting CP extension adjustment for uplink communications) .

The inter-station communications manager 1245 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1245 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1245 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1235 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1235 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1235 may not be directly executable by the processor 1240 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 13 shows a flowchart illustrating a method 1300 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1300 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may perform aspects of the functions described herein using special-purpose hardware.

At 1305, the UE may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

At 1310, the UE may determine, based on the CP configuration, to report CP information of the UE to the base station. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a determination component as described with reference to FIGs. 5 through 8.

At 1315, the UE may transmit a report to the base station that includes the CP information based on the determining. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a report transmitter as described with reference to FIGs. 5 through 8.

FIG. 14 shows a flowchart illustrating a method 1400 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1400 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may perform aspects of the functions described herein using special-purpose hardware.

At 1405, the UE may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

At 1410, the UE may determine a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by an extension manager as described with reference to FIGs. 5 through 8.

At 1415, the UE may determine that the CP extension satisfies a threshold. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a threshold component as described with reference to FIGs. 5 through 8.

At 1420, the UE may determine, based on the CP configuration, to report CP information of the UE to the base station. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a determination component as described with reference to FIGs. 5 through 8.

At 1425, the UE may transmit a report based on determining that the CP extension satisfies the threshold. The operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be performed by a report transmitter as described with reference to FIGs. 5 through 8.

FIG. 15 shows a flowchart illustrating a method 1500 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may perform aspects of the functions described herein using special-purpose hardware.

At 1505, the UE may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

At 1510, the UE may determine a CP extension based on one or more configuration parameters of the CP configuration and a TA of the UE. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by an extension manager as described with reference to FIGs. 5 through 8.

At 1515, the UE may determine the one or more extension parameters based on a proximity of the CP extension to one symbol length or zero. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by an extension manager as described with reference to FIGs. 5 through 8.

At 1520, the UE may determine, based on the CP configuration, to report CP information of the UE to the base station. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a determination component as described with reference to FIGs. 5 through 8.

At 1525, the UE may transmit a report to the base station that includes the CP information based on the determining. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be performed by a report transmitter as described with reference to FIGs. 5 through 8.

At 1530, the UE may transmit one or more extension parameters in the report to the base station. The operations of 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of 1530 may be performed by a report transmitter as described with reference to FIGs. 5 through 8.

FIG. 16 shows a flowchart illustrating a method 1600 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may perform aspects of the functions described herein using special-purpose hardware.

At 1605, the UE may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

At 1610, the UE may determine, based on the CP configuration, to transmit a RACH signal to the base station. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a determination component as described with reference to FIGs. 5 through 8.

At 1615, the UE may transmit the RACH signal to the base station that indicates a TA of the UE based on the determining. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed by a RACH transmitter as described with reference to FIGs. 5 through 8.

FIG. 17 shows a flowchart illustrating a method 1700 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may perform aspects of the functions described herein using special-purpose hardware.

At 1705, the UE may receive, from a base station, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

At 1710, the UE may determine a CP extension based on one or more configuration parameters of the CP configuration and the TA of the UE. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by an extension manager as described with reference to FIGs. 5 through 8.

At 1715, the UE may determine, based on the CP configuration, to transmit a RACH signal to the base station. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed by a determination component as described with reference to FIGs. 5 through 8.

At 1720, the UE may transmit the RACH signal to the base station that indicates a TA of the UE based on the determining, the RACH signal indicating modification of the CP configuration. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed by a RACH transmitter as described with reference to FIGs. 5 through 8.

At 1725, the UE may receive a second CP configuration from the base station based on the RACH signal, where the second CP configuration includes at least one configuration parameter different from the CP configuration. The operations of 1725 may be performed according to the methods described herein. In some examples, aspects of the operations of 1725 may be performed by a configuration receiver as described with reference to FIGs. 5 through 8.

FIG. 18 shows a flowchart illustrating a method 1800 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1800 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1800 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, a base station may perform aspects of the functions described herein using special-purpose hardware.

At 1805, the base station may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

At 1810, the base station may receive, from the UE, an indication to modify one or more configuration parameters of the CP configuration. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed by an indication receiver as described with reference to FIGs. 9 through 12.

At 1815, the base station may modify the one or more configuration parameters based on the indication. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed by a modification component as described with reference to FIGs. 9 through 12.

At 1820, the base station may transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters. The operations of 1820 may be performed according to the methods described herein. In some examples, aspects of the operations of 1820 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

FIG. 19 shows a flowchart illustrating a method 1900 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 1900 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1900 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, a base station may perform aspects of the functions described herein using special-purpose hardware.

At 1905, the base station may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

At 1910, the base station may receive a report indicating that a CP extension at the UE satisfies a threshold. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed by a report receiver as described with reference to FIGs. 9 through 12.

At 1915, the base station may determine to modify one or more configuration parameters of the CP configuration. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed by an indication receiver as described with reference to FIGs. 9 through 12.

At 1920, the base station may modify the one or more configuration parameters based on the indication. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed by a modification component as described with reference to FIGs. 9 through 12.

At 1925, the base station may transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters. The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

FIG. 20 shows a flowchart illustrating a method 2000 that supports CP extension adjustment for uplink communications in accordance with aspects of the present disclosure. The operations of method 2000 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2000 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, a base station may perform aspects of the functions described herein using special-purpose hardware.

At 2005, the base station may transmit, to a UE, a CP configuration for extension of a CP for uplink transmissions by the UE. The operations of 2005 may be performed according to the methods described herein. In some examples, aspects of the operations of 2005 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

At 2010, the base station may receive a report indicating a TA of the UE. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed by a report receiver as described with reference to FIGs. 9 through 12.

At 2015, the base station may determine to modify one or more configuration parameters of the CP configuration. The operations of 2015 may be performed according to the methods described herein. In some examples, aspects of the operations of 2015 may be performed by an indication receiver as described with reference to FIGs. 9 through 12.

At 2020, the base station may modify the one or more configuration parameters based on the indication. The operations of 2020 may be performed according to the methods described herein. In some examples, aspects of the operations of 2020 may be performed by a modification component as described with reference to FIGs. 9 through 12.

At 2025, the base station may transmit, to the UE, a second CP configuration for extension of the CP for uplink transmission by the UE, the second CP configuration including the modified one or more configuration parameters. The operations of 2025 may be performed according to the methods described herein. In some examples, aspects of the operations of 2025 may be performed by a configuration transmitter as described with reference to FIGs. 9 through 12.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, 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 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, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications at a user equipment (UE) , comprising:

receiving, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determining, based at least in part on the cyclic prefix configuration, to report cyclic prefix information of the UE to the base station; and

transmitting a report to the base station that includes the cyclic prefix information based at least in part on the determining.
The method of claim 1, further comprising:

determining a cyclic prefix extension based at least in part on one or more configuration parameters of the cyclic prefix configuration and a timing advance of the UE;

determining that the cyclic prefix extension satisfies a threshold; and

transmitting the report based at least in part on determining that the cyclic prefix extension satisfies the threshold.
The method of claim 2, wherein the threshold comprises one symbol length or zero.
The method of claim 1, further comprising:

transmitting one or more extension parameters in the report to the base station.
The method of claim 4, further comprising:

determining a cyclic prefix extension based at least in part on one or more configuration parameters of the cyclic prefix configuration and a timing advance of the UE; and

determining the one or more extension parameters based at least in part on a proximity of the cyclic prefix extension to one symbol length or zero.
The method of claim 1, further comprising:

determining a cyclic prefix extension based at least in part on one or more configuration parameters of the cyclic prefix configuration and a timing advance of the UE;

determining a second set of one or more configuration parameters based at least in part on the cyclic prefix extension and a target cyclic prefix duration; and

transmitting the second set of one or more configuration parameters in the report to the base station.
The method of claim 6, further comprising:

transmitting the second set of one or more configuration parameters via a medium access control control element.
The method of claim 1, further comprising:

receiving a configuration from the base station that indicates periodic reporting of the cyclic prefix information at the UE; and

periodically transmitting the report based at least in part on the configuration.
The method of claim 1, further comprising:

receiving a message from the base station that triggers reporting of the cyclic prefix information at the UE; and

transmitting the report based at least in part on the message.
The method of claim 1, further comprising:

transmitting a timing advance of the UE in the report to the base station.
A method for wireless communications at a user equipment (UE) , comprising:

receiving, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determining, based at least in part on the cyclic prefix configuration, to transmit a random access channel signal to the base station; and

transmitting the random access channel signal to the base station that indicates a timing advance of the UE based at least in part on the determining.
The method of claim 11, further comprising:

determining a cyclic prefix extension based at least in part on one or more configuration parameters of the cyclic prefix configuration and the timing advance of the UE;

determining that the cyclic prefix extension satisfies a threshold; and

transmitting the random access channel signal based at least in part on determining that the cyclic prefix extension satisfies the threshold.
The method of claim 11, further comprising:

determining a cyclic prefix extension based at least in part on one or more configuration parameters of the cyclic prefix configuration and the timing advance of the UE; and

transmitting the random access channel signal indicating modification of the cyclic prefix configuration.
The method of claim 13, further comprising:

receiving a second cyclic prefix configuration from the base station based at least in part on the random access channel signal, wherein the second cyclic prefix configuration comprises at least one configuration parameter different from the cyclic prefix configuration.
The method of claim 11, further comprising:

receiving a message from the base station that triggers transmission of the random access channel signal by the UE; and

transmitting the random access channel signal in response to the message.
The method of claim 15, further comprising:

periodically transmitting the random access channel signal based at least in part on the message indicating periodic transmission of the random access channel signal by the UE.
A method for wireless communications at a base station, comprising:

transmitting, to a user equipment (UE) , a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

receiving, from the UE, an indication to modify one or more configuration parameters of the cyclic prefix configuration;

modifying the one or more configuration parameters based at least in part on the indication; and

transmitting, to the UE, a second cyclic prefix configuration for extension of the cyclic prefix for uplink transmission by the UE, the second cyclic prefix configuration comprising the modified one or more configuration parameters.
The method of claim 17, wherein receiving the indication comprises:

receiving a report indicating that a cyclic prefix extension at the UE satisfies a threshold.
The method of claim 18, wherein the threshold comprises one symbol length or zero.
The method of claim 17, wherein receiving the indication comprises:

receiving a report indicating at least one configuration parameter for a cyclic prefix extension of the UE.
The method of claim 20, further comprising:

modifying the one or more configuration parameters according to the at least one configuration parameter, wherein the second cyclic prefix configuration includes the at least one configuration parameter.
The method of claim 17, receiving the indication comprises:

receiving a report indicating a timing advance of the UE.
The method of claim 22, further comprising:

modifying the one or more configuration parameters based at least in part on the timing advance.
The method of claim 17, receiving the indication comprises:

receiving a random access channel signal indicating a timing advance of the UE.
The method of claim 24, further comprising:

modifying the one or more configuration parameters based at least in part on the timing advance.
An apparatus for wireless communications at a user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determine, based at least in part on the cyclic prefix configuration, to report cyclic prefix information of the UE to the base station; and

transmit a report to the base station that includes the cyclic prefix information based at least in part on the determining.
An apparatus for wireless communications at a user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determine, based at least in part on the cyclic prefix configuration, to transmit a random access channel signal to the base station; and

transmit the random access channel signal to the base station that indicates a timing advance of the UE based at least in part on the determining.
An apparatus for wireless communications at a base station, comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

transmit, to a user equipment (UE) , a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

receive, from the UE, an indication to modify one or more configuration parameters of the cyclic prefix configuration;

modify the one or more configuration parameters based at least in part on the indication; and

transmit, to the UE, a second cyclic prefix configuration for extension of the cyclic prefix for uplink transmission by the UE, the second cyclic prefix configuration comprising the modified one or more configuration parameters.
An apparatus for wireless communications at a user equipment (UE) , comprising:

means for receiving, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

means for determining, based at least in part on the cyclic prefix configuration, to report cyclic prefix information of the UE to the base station; and

means for transmitting a report to the base station that includes the cyclic prefix information based at least in part on the determining.
An apparatus for wireless communications at a user equipment (UE) , comprising:

means for receiving, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

means for determining, based at least in part on the cyclic prefix configuration, to transmit a random access channel signal to the base station; and

means for transmitting the random access channel signal to the base station that indicates a timing advance of the UE based at least in part on the determining.
An apparatus for wireless communications at a base station, comprising:

means for transmitting, to a user equipment (UE) , a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

means for receiving, from the UE, an indication to modify one or more configuration parameters of the cyclic prefix configuration;

means for modifying the one or more configuration parameters based at least in part on the indication; and

means for transmitting, to the UE, a second cyclic prefix configuration for extension of the cyclic prefix for uplink transmission by the UE, the second cyclic prefix configuration comprising the modified one or more configuration parameters.
A non-transitory computer-readable medium storing code for wireless communications at a user equipment (UE) , the code comprising instructions executable by a processor to:

receive, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determine, based at least in part on the cyclic prefix configuration, to report cyclic prefix information of the UE to the base station; and

transmit a report to the base station that includes the cyclic prefix information based at least in part on the determining.
A non-transitory computer-readable medium storing code for wireless communications at a user equipment (UE) , the code comprising instructions executable by a processor to:

receive, from a base station, a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

determine, based at least in part on the cyclic prefix configuration, to transmit a random access channel signal to the base station; and

transmit the random access channel signal to the base station that indicates a timing advance of the UE based at least in part on the determining.
A non-transitory computer-readable medium storing code for wireless communications at a base station, the code comprising instructions executable by a processor to:

transmit, to a user equipment (UE) , a cyclic prefix configuration for extension of a cyclic prefix for uplink transmissions by the UE;

receive, from the UE, an indication to modify one or more configuration parameters of the cyclic prefix configuration;

modify the one or more configuration parameters based at least in part on the indication; and

transmit, to the UE, a second cyclic prefix configuration for extension of the cyclic prefix for uplink transmission by the UE, the second cyclic prefix configuration comprising the modified one or more configuration parameters.