Beam refinement technique for random access communication

Abstract

Methods, systems, and apparatus for wireless communications are described in which a base station and a user equipment (UE) can perform beam refinement within a random access procedure. The UE can transmit a random access request to a base station, and in response thereto, the base station can transmit a control channel command to the UE indicating that a modified random access request is to be transmitted. Resources for the modified random access request can be determined based on the random access request, the control channel command, configured resources, or a combination thereof. The base station can monitor the modified random access request using different beamforming parameters and determine a refined beam for subsequent transmissions in the random access procedure. The base station can transmit a random access response to the UE using the refined beam and complete the access procedure.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 011,764, entitled “Beam Refinement Techniques for Random Access Communications,” filed by Sun et al. on April 17, 2020, and U.S. Patent Application No. 17 / 231,805, entitled “Beam Refinement Techniques for Random Access Communications,” filed by Sun et al. on April 15, 2021, each of which is assigned to the assignee of this application. Technical Field

[0003] The following relates generally to wireless communications and, more particularly, to beam refinement techniques for random access communications. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, etc. These systems may be able to support communication with multiple users by sharing 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, advanced LTE (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 use various technologies, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform extended orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting the communication of multiple communication devices, which may be referred to as user equipment (UE) in addition.

[0005] In mmW systems, a base station and a UE may communicate via one or more directional beams. A transmitter (e.g., a base station) may participate in a beam sweeping process to establish an active beam pair with a receiver (e.g., a UE). An active beam pair may include an active transmit beam of a transmitter and a corresponding active receive beam of a receiver. The transmit beam and receive beam in an active beam pair may be refined, for example, by a beam refinement procedure. It may be expected that a more efficient beam refinement technique may be provided to help enhance network efficiency.

[0006] Overview

[0007] The described technology relates to improved methods, systems, devices and apparatuses for supporting random access with beam refinement in wireless communications. The various described technologies provide that a base station and a user equipment (UE) can use multiple transmissions associated with an access procedure (e.g., a random access procedure) to refine the beam for a subsequent portion of the access procedure. In some cases, the UE may transmit a random access request to the base station, and in response thereto, the base station may transmit a physical downlink control channel (PDCCH) command to the UE. The PDCCH command may indicate that the UE is to transmit one or more modified random access requests to the base station. Resources and transmission parameters for the one or more modified random access requests may be determined based on the various technologies discussed herein.

[0008] In some cases, the random access opportunities (ROs) used to transmit the initial random access request and the modified random access request may each be associated with the same synchronization signal block. In some cases, a first preamble subset may be used for the initial random access request, and a second preamble subset may be used for the modified random access request, and the initial and modified random access requests may be distinguished based on the associated preamble sequence. In some cases, a separate RO set may be configured for the modified random access request that is separate from the initial RO set for the initial random access request. In some cases, the RO for the modified random access request may not be associated with a specific SSB, and such RO may be identified based on one or more configured parameters, which may be triggered by a PDCCH command.

[0009] The base station may monitor the one or more modified random access requests using different beamforming parameters to determine a refined beam to be used for subsequent transmissions in the random access procedure. The base station may then transmit a random access response to the UE using the refined beam and complete the access procedure. The refined beam may provide more reliable reception of the random access response at the UE and thereby improve the reliability and efficiency of communications.

[0010] A method of wireless communication at a UE is described. The method may include transmitting to a base station an initial random access request to establish a wireless connection with the base station, receiving a control channel command from the base station in response to the initial random access request, determining a resource set for one or more modified random access requests based on the control channel command, transmitting the one or more modified random access requests using the determined resource set, and receiving a random access response from the base station in response to the one or more modified random access requests.

[0011] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor so that the apparatus: transmits an initial random access request to a base station to establish a wireless connection with the base station, receives a control channel command from the base station in response to the initial random access request, determines a resource set for one or more modified random access requests based on the control channel command, transmits the one or more modified random access requests using the determined resource set, and receives a random access response from the base station in response to the one or more modified random access requests.

[0012] Another apparatus for wireless communication at a UE is described. The apparatus may include means for transmitting to a base station an initial random access request to establish a wireless connection with the base station, receiving a control channel command from the base station in response to the initial random access request, determining a resource set for one or more modified random access requests based on the control channel command, transmitting the one or more modified random access requests using the determined resource set, and receiving a random access response from the base station in response to the one or more modified random access requests.

[0013] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to transmit an initial random access request to a base station to establish a wireless connection with the base station, receive a control channel command from the base station in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, transmit the one or more modified random access requests using the determined resource set, and receive a random access response from the base station in response to the one or more modified random access requests.

[0014] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying one or more parameters for the one or more modified random access requests based on a first random access opportunity having the same random access opportunity configuration as the initial random access request. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying a resource set in a subsequent random access opportunity of the first random access opportunity based on a control channel command, wherein the subsequent random access opportunity is associated with the same synchronization signal block (SSB) as the first random access opportunity. Some examples of the methods, devices (equipment), and non-transitory computer-readable media described herein may further include operations, features, devices, or instructions for the following actions: selecting a first preamble sequence for the one or more modified random access requests from a first preamble sequence subset associated with the first random access opportunity, wherein the first preamble sequence subset does not overlap with a second preamble sequence subset available for the initial random access request associated with the first random access opportunity.

[0015] In some examples of the methods, devices, and non-transitory computer-readable media described herein, the determining may further include operations, features, means, or instructions for the following actions: identifying a resource set for the one or more modified random access requests based on a second random access opportunity configuration different from the first random access opportunity configuration of the initial random access request. In some examples of the methods, devices, and non-transitory computer-readable media described herein, the second random access opportunity configuration is received in RRC signaling from the base station.

[0016] In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, the second random access opportunity configuration includes configuration parameters for one or more of: a time resource for the second random access opportunity, a frequency resource for the second random access opportunity, a number of repetitions of the modified random access request that may be transmitted, or any combination thereof. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, a periodic resource set is provided for the one or more modified random access requests.

[0017] In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for an initial random access request. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, a set of different random access opportunities for transmitting a modified random access request is configured for each SSB in a set of different SSBs. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the second random access opportunity configuration is not associated with any synchronization signal block (SSB). In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, a set of different random access opportunities for transmitting a modified random access request is shared by two or more different SSBs. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying the resource set based on an indication provided by a control channel command.

[0018] Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: receiving a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests in RRC signaling, and wherein a control channel command triggers the transmission of the one or more modified random access requests in the random access opportunity. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, RRC signaling provides one or more of the time resources or frequency resources for the random access opportunity, the number of repetitions of the one or more modified random access requests, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the control channel command serves as an uplink grant for the one or more modified random access requests using the resource set. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the resource set may be determined based on the location of the control channel command. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the time domain location of the resource set may be based on a time offset from the control channel command. In some examples of the methods, apparatus (equipment), and non-transitory computer-readable media described herein, the time domain position of the resource set may be based on a fixed time offset from a control channel command or a time offset indicated by one or more bits in a control channel command.

[0019] Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: determining a second preamble for the one or more modified random access requests as a function of a first random access opportunity associated with an initial random access request, a first preamble of the initial random access request, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the function may be further based on a control value provided in a control channel command. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the same preamble may be used for each of two or more repetitions of a modified random access request, or a different preamble may be used for each of two or more repetitions of a modified random access request based on a frequency hopping algorithm. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, a starting random access opportunity index associated with the resource set may be determined based on a time domain position of a control channel command. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, a starting time domain resource of the resource set may be based on an initial time domain resource corresponding to a synchronization signal block (SSB) index associated with an initial random access request and a fixed or signaled time domain offset from a second time domain resource of a control channel command.

[0020] Some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for the following actions: determining a second random access preamble for the one or more modified random access requests as a function of the first random access preamble for the initial random access request. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, the resource set includes resources in the second random access opportunity, which are determined as a function of the first random access opportunity associated with the initial random access request.

[0021] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, means, or instructions for the following actions: selecting a resource set from a configured number of available resources for transmitting the one or more modified random access requests, and wherein the selection is based on one or more of the timing of a control channel command or an offset indicated by the control channel command. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, means, or instructions for the following actions: identifying a set of configured parameters for random access opportunities associated with the one or more modified random access requests, and determining a location of the resource set based on the set of configured parameters and one or more of the timing of a control channel command or an offset indicated by a control channel command.

[0022] A method of wireless communication at a base station is described. The method may include receiving an initial random access request from a UE to establish a wireless connection with the base station, transmitting a control channel command to the UE in response to the initial random access request, determining a resource set for one or more modified random access requests based on the control channel command, monitoring the one or more modified random access requests using the determined resource set, and transmitting a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests.

[0023] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: receive an initial random access request from a UE for establishing a wireless connection with a base station, transmit a control channel command to the UE in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, monitor the one or more modified random access requests using the determined resource set, and transmit a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests.

[0024] Another apparatus for wireless communications at a base station is described. The apparatus may include means for receiving an initial random access request from a UE for establishing a wireless connection with the base station, transmitting a control channel command to the UE in response to the initial random access request, determining a resource set for one or more modified random access requests based on the control channel command, monitoring the one or more modified random access requests using the determined resource set, and transmitting a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests.

[0025] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to receive an initial random access request from a UE to establish a wireless connection with the base station, transmit a control channel command to the UE in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, monitor the one or more modified random access requests using the determined resource set, and transmit a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests.

[0026] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying one or more parameters for the one or more modified random access requests based on a first random access opportunity having the same random access opportunity configuration as the initial random access request. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying a resource set in a subsequent random access opportunity of the first random access opportunity based on a control channel command, wherein the subsequent random access opportunity is associated with the same synchronization signal block (SSB) as the first random access opportunity. In some examples of the methods, devices (equipment), and non-transitory computer-readable media described herein, a first preamble sequence subset of the first random access opportunity is associated with the initial random access request message, and a second preamble sequence subset of the first random access opportunity is associated with the modified random access message, wherein the first preamble sequence subset does not overlap with the second preamble sequence subset.

[0027] In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the determination may further include operations, features, devices, or instructions for the following actions: identifying a resource set for the one or more modified random access requests based on a second random access opportunity configuration different from the first random access opportunity configuration of the initial random access request. Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: transmitting the second random access opportunity configuration to the UE in RRC signaling. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the second random access opportunity configuration includes parameters for one or more of the following: time resources for the second random access opportunity, frequency resources for the second random access opportunity, the number of repetitions of the modified random access request to be transmitted, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, a periodic resource set is provided for the one or more modified random access requests.

[0028] In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the second random access opportunity configuration may be associated with a synchronization signal block (SSB) used to identify uplink resources for an initial random access request. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, a set of different random access opportunities for transmitting a modified random access request may be configured for each SSB in a plurality of different SSBs. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the second random access opportunity configuration may not be associated with any synchronization signal block (SSB). In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, a set of different random access opportunities for transmitting a modified random access request is shared by two or more different SSBs. Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: providing an indication identifying the resource set to the UE in a control channel command.

[0029] Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: transmitting a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests in RRC signaling, and wherein a control channel command triggers the transmission of the one or more modified random access requests in the random access opportunity. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, RRC signaling provides one or more of a time resource or a frequency resource for a random access opportunity, a number of repetitions of the one or more modified random access requests, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the control channel command acts as an uplink grant for the one or more modified random access requests using the resource set.

[0030] In some examples of the methods, apparatuses (equipment), and non-transient computer-readable media described herein, the resource set may be determined based on the location of the control channel command. In some examples of the methods, apparatuses (equipment), and non-transient computer-readable media described herein, the time domain location of the resource set may be based on a time offset from the control channel command. In some examples of the methods, apparatuses (equipment), and non-transient computer-readable media described herein, the time domain location of the resource set may be based on a fixed time offset from the control channel command or a time offset indicated by one or more bits in the control channel command.

[0031] Some examples of the methods, devices (equipment) and non-transient computer-readable media described herein may further include operations, features, devices or instructions for the following actions: determining that the one or more modified random access requests are associated with the UE based on the preamble of the one or more modified random access requests as a function of the first random access opportunity associated with the initial random access request, the first preamble of the initial random access request, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the function may be further based on the control value provided in the control channel command. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the function outputs one or more of the frequency domain index for the one or more modified random access requests, the preamble index for the one or more modified random access requests, or any combination thereof. In some examples of the methods, devices (equipment) and non-transient computer-readable media described herein, the same preamble may be used for each of two or more repetitions of the modified random access request, or a different preamble may be used for each of two or more repetitions of the modified random access request based on a frequency hopping algorithm.

[0032] In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, a starting random access opportunity index associated with the resource set may be determined based on a time domain position of a control channel command. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, a starting time domain resource of the resource set may be based on an initial time domain resource corresponding to a synchronization signal block (SSB) index associated with an initial random access request and a fixed or signaled time domain offset from a second time domain resource of a control channel command.

[0033] In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, the second random access preamble for the one or more modified random access requests may be a function of the first random access preamble for the initial random access request. In some examples of the methods, apparatuses (equipment), and non-transitory computer-readable media described herein, the resource set includes resources in a second random access opportunity, and the second random access opportunity may be determined as a function of the first random access opportunity associated with the initial random access request.

[0034] Some examples of the methods, devices (equipment), and non-transitory computer-readable media described herein may further include operations, features, devices, or instructions for the following actions: configuring a number of available resources for the UE to transmit the one or more modified random access requests, and wherein the resource set is selected from the number of available resources based on one or more of the timing of the control channel command or the offset indicated by the control channel command. Some examples of the methods, devices (equipment), and non-transitory computer-readable media described herein may further include operations, features, devices, or instructions for the following actions:

[0035] configuring a set of parameters for random access opportunities associated with the one or more modified random access requests, and

[0036] The location of the resource set is based on one or more of a configured parameter set and a timing of a control channel command or an offset indicated by the control channel command. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 An example of a wireless communication system supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is illustrated.

[0039] Figure 2 An example of a portion of a wireless communication system supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is illustrated.

[0040] Figure 3 Examples of uplink and downlink transmissions supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure are illustrated.

[0041] Figures 4 to 6 Examples of random access opportunities supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure are illustrated.

[0042] Figure 7 An example of a triggered random access opportunity for a modified random access request supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is illustrated.

[0043] Figure 8 An example of a process flow supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is illustrated.

[0044] Fig. 9 and Fig.10 A block diagram of an apparatus supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0045] Fig.11 A block diagram of a communication manager supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0046] Fig.12 A diagram of a system including devices supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0047] Fig.13 and Fig.14 A block diagram of an apparatus supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0048] Fig.15 A block diagram of a communication manager supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0049] Fig.16 A diagram of a system including devices supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0050] Figures 17 to 24 A flow chart illustrating a method of supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown.

[0051] Detailed Description

[0052] Various techniques described provide for refinement of beamforming parameters as part of a random access procedure. In some cases, a base station and a user equipment (UE) may use multiple transmissions associated with an access procedure (e.g., a random access procedure for initial access between a UE and a base station) to refine beams for subsequent portions of the access procedure. In some cases, the UE may transmit a random access request to a base station, and in response thereto, the base station may transmit a physical downlink control channel (PDCCH) command to the UE. The PDCCH command may indicate that the UE is to transmit one or more modified random access requests to the base station. Resources and parameters for the one or more modified random access requests may be identified based on techniques such as those discussed herein. The base station may monitor the one or more modified random access requests using different beamforming parameters to determine a refined beam to be used for subsequent transmissions in the random access procedure. The base station may then transmit a random access response to the UE using the refined beam and complete the access procedure.

[0053] In some cases, such techniques may be used in millimeter wave (mmW) systems, where a base station and a UE may communicate via one or more directional beams, and the base station may engage in beam sweeping operations when transmitting synchronization signal blocks (SSBs), which are detected at the UE and used to identify random access resources for an initial access procedure and to establish active transmit beams for communication. In some cases, as part of the beam sweeping procedure, the base station may perform sector sweeping with wide shaped lower gain beams, which may be transmitted to a particular sector or geographic area in an SSB, and then subsequent beams may be transmitted to another sector or geographic area in a subsequent SSB. In some cases, each SSB has an associated uplink resource, and the UE may transmit an uplink transmission, such as a random access request, using a random access channel (RACH) in the uplink resources associated with the SSB in which the UE receives the strongest downlink. Thus, different uplink resources associated with different beams in a beam sweeping procedure may provide time resource partitioning, and UE transmissions in specific uplink resources may provide feedback to the base station, for example, of the wide shaped beam that the UE receives with the highest gain.

[0054] In some existing systems, an initial access procedure (such as a RACH procedure) may provide for a UE to acquire a cell by reading an SSB and a system information block (e.g., SIB1), wherein the system information block provides initial access related parameters. The UE may then transmit a random access request, which may be referred to as message 1 or MSG1. In some cases, the RACH procedure may use open-loop power control, wherein the UE may transmit MSG1 at an initial power level and monitor for responses, and then incrementally increase the power level in one or more subsequent transmissions of MSG1 until a random access response from the base station is detected. The base station transmits a random access response upon detecting MSG1, which may be referred to as message 2 or MSG2, which may include a PDCCH portion and a physical downlink shared channel (PDSCH) portion. In some cases, the PDCCH may be scrambled with a random access radio network temporary identifier (RA-RNTI), which is a function of the random access opportunity (RO) used by the UE to send MSG1 (e.g., based on the best SSB detected at the UE). Within the PDSCH portion, a media access control (MAC) control element (CE) may acknowledge the receipt of MSG1 and grant the UE an uplink grant to send message 3 (MSG3) which may include the UE identity. The UE may monitor PDCCH communications (e.g., downlink control information (DCI) format 1_0) scrambled with a RA-RNTI corresponding to the RO used by the UE to transmit MSG1, and if detected, proceed with PDSCH decoding. If a MAC-CE is found in the PDSCH, thus appended to the random access preamble used by the UE to transmit MSG1, the UE will treat the MAC-CE as for itself and send its UE-ID in MSG3 following the UL grant. In the event of a collision by multiple UEs each transmitting MSG3 at the same resource (e.g., if they use the same preamble sequence to transmit MSG1 in the same RO), the base station may identify the collision and perform contention resolution before transmitting an uplink grant in message 4 (MSG4) from the base station.

[0055] In situations where communications use mmW frequencies, as indicated above, SSBs may be transmitted using relatively wide beams (e.g., the limitation of 64 beams that can be supported in a given cell), while the final serving beam to the UE may be narrower and have a higher beamforming gain. In some systems, the bottleneck of the initial access process may be related to the random access response (MSG2) transmission, where the UE may not detect the MSG2 transmission from the base station, which may result in inefficiency (due to the UE continuing to transmit a higher-power MSG1 transmission or attempting a completely new initial access procedure). Such MSG2-related bottlenecks may be caused by the base station using the same transmit beam for MSG2 as used for the associated SSB, which may have a relatively low beamforming gain. In addition, the MSG2 transmission does not have confirmation feedback (e.g., hybrid automatic repeat request (HARQ) feedback) to indicate to the base station whether the transmission was successfully received, so the base station may not be aware that the UE did not receive MSG2.

[0056] In some cases, the UE may transmit one or more additional signals as part of the random access procedure, which may be measured at the base station using different receive beamforming parameters in order to refine the beam used to transmit MSG2. In some cases, the base station may transmit a PDCCH command in response to receiving a random access request, which may trigger the UE to transmit one or more modified random access requests using the same transmit beam, which may allow the base station to perform beam refinement. Given the beam correspondence, the refined receive beam may be used as a refined transmit beam for MSG2 transmission. By using the PDCCH command, the UE does not transmit the modified random access request unnecessarily, and thus may save resources. In addition, such a PDCCH command may be more likely to be received at the UE than a conventional MSG2 transmission, because the command may have a relatively small payload and therefore may have a relatively large decoding gain compared to a conventional MSG2, which may compensate for the relatively low beamforming gain.

[0057] In some cases, in addition to monitoring MSG2, the UE may also monitor PDCCH commands. The PDCCH command may be scrambled by a RA-RNTI that may be monitored by the UE in a manner similar to the MSG2 PDCCH, and the PDCCH command may carry a preamble index to confirm which UE should follow. In some cases, the PDCCH command may indicate resources for beam refinement signal transmission, or multiple resources for multiple beam refinement signal transmissions. In some cases, multiple rounds of PDCCH commands and beam refinement signals may be supported. As used herein, a PDCCH command may be referred to as a control channel command, a compressed PDCCH command, or MSG2', and a beam refinement signal may be referred to as a modified random access request or MSG1'.

[0058] In some cases, the random access opportunities (ROs) used to transmit the initial random access request and the modified random access request may each be associated with the same SSB. In some cases, a first random access preamble subset of the RO may be used for the initial random access request, and a second random access preamble subset of the RO may be used for the modified random access request, and the initial and modified random access requests may be distinguished based on the associated preamble sequence. In some cases, a separate RO set may be configured for the modified random access request that is separate from the initial RO set for the initial random access request. In some cases, the RO for the modified random access request may not be associated with a specific SSB, and such RO may be identified based on one or more configured parameters, which may be triggered by a PDCCH command.

[0059] Providing such beam refinement during an access procedure can provide a more reliable network access procedure. For example, in response to a PDCCH command, beam refinement based on one or more modified random access requests can increase the likelihood of receiving a random access response at the UE. Such techniques can therefore allow more efficient and reliable access, and thus improve the reliability and efficiency of the associated wireless communication network. In addition, for example, the techniques as discussed herein can reduce the number of downlink and uplink transmissions, and thus reduce power consumption at the UE. Additionally, in situations where mmW transmissions use shared or unlicensed frequency spectrum bands, the reduction in the number of transmissions between the UE and the base station is beneficial because it reduces the likelihood that the access procedure will be interrupted if different transmitters obtain a wireless channel.

[0060] Various aspects of the present disclosure are initially described in the context of a wireless communication system. Examples of uplink and downlink communications, and modified access requests with associated resources are then discussed. Various aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow charts related to beam refinement techniques for random access communications.

[0061] Figure 1 An example of a wireless communication system 100 supporting beam refinement techniques for random access communications in accordance with various aspects of the present disclosure is illustrated. The wireless communication 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 communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication 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.

[0062] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be different forms of devices or devices with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly 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 stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support communication of signals according to one or more radio access technologies.

[0063] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be different forms of devices or devices with different capabilities. Figure 1 Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), such as Figure 1 as shown in .

[0064] Each base station 105 may communicate with the core network 130, or communicate with each other, or both. For example, the base station 105 may interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105), or indirectly (e.g., via the core network 130), or directly and indirectly on the backhaul link 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul link 120 may be or include one or more wireless links.

[0065] One or more of the base stations 105 described herein may include or may be referred to by a person of ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a B node, an evolved B node (eNB), a next generation B node or a gigabit B node (any of which may be referred to as a gNB), a home B node, a home evolved B node, or other suitable terminology.

[0066] 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 term, where a "device" may also be referred to as a unit, a station, a terminal, or a client, etc. 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, 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 communication (MTC) device, etc., which may be implemented in various objects such as electrical appliances or vehicles, meters, etc.

[0067] The UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as base stations 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc. Figure 1 as shown in .

[0068] The UE 115 and the base station 105 may communicate wirelessly with each other via one or more communication links 125 on 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 link 125. For example, a carrier for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP)) that operates 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 for coordinating carrier operations, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The UE 115 may be configured to have multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used in conjunction with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0069] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates the operation of other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel grid for discovery by UE 115. A carrier may operate in a standalone mode in which initial acquisition and connection may be made by UE 115 via the carrier, or a carrier may operate in a non-standalone mode in which a connection is anchored using a different carrier (e.g., a different carrier of the same or different radio access technology).

[0070] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in an FDD mode), or may be configured to carry both downlink and uplink communications (e.g., in a TDD mode).

[0071] A carrier may be associated with a particular bandwidth of a radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as a "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of several determined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)) of a carrier of a particular radio access technology. Devices (e.g., base stations 105, UEs 115, or both) of the wireless communication system 100 may have a hardware configuration that supports communications on a particular carrier bandwidth, or may be configurable to support communications on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or UE 115 that supports simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., subband, BWP) or all of a carrier bandwidth.

[0072] The signal waveform transmitted on the carrier may include 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 using MCM technology, a resource element may include a code element period (e.g., the duration of a modulation code element) and a subcarrier, where the code element period and the 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 code rate of the modulation scheme, or both). Thus, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 can be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers can further improve the data rate or data integrity of communication with UE 115.

[0073] The time interval of the base station 105 or the UE 115 can be expressed as a multiple of a basic time unit, and the basic time unit can be, for example, a sampling period T s =1 / (Δf max ·N f ) seconds, where Δf max It can represent the maximum supported subcarrier spacing, and N fThe maximum supported discrete Fourier transform (DFT) size may be indicated. Time intervals of communication resources 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).

[0074] Each frame may include a plurality of consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of code element periods (e.g., depending on the length of the cyclic prefix added before each code element period). In some wireless communication systems 100, a time slot may be further divided into a plurality of mini-time slots containing one or more code elements. Excluding the cyclic prefix, each code element period may contain one or more (e.g., N f The duration of a symbol period may depend on the subcarrier spacing or the operating band.

[0075] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication 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 communication system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0076] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. 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 a system bandwidth or a subset of a system bandwidth of a carrier. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more 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 the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0077] In some examples, base stations 105 may be mobile and thus provide communication coverage for mobile geographic coverage areas 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, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0078] The wireless communication system 100 may be configured to support ultra-reliable communication or low latency communication or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low latency communication (URLLC) or mission-critical communication. UE 115 may be designed to support ultra-reliable, low latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication 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, critical mission, and ultra-reliable low latency may be used interchangeably herein.

[0079] In some examples, UE 115 may also be able to communicate directly with other UE 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 communication may be within a 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 the base station 105, or may not be able to receive transmissions from the base station 105 for other reasons. In some examples, each group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between each UE 115 without involving the base station 105.

[0080] 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 a 5G core (5GC), and the EPC or 5GC may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing packets or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by a base station 105 associated with the core network 130. User IP packets may be delivered via a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. Operator IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0081] Some network devices (such as base stations 105) may include subcomponents, such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with each UE 115 through one or more other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the 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 merged into a single network device (e.g., base station 105).

[0082] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). In general, the 300 MHz to 3 GHz region is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from about 1 decimeter to 1 meter long. UHF waves may be blocked or redirected by buildings and environmental features, but these waves may penetrate various structures sufficiently for macro cells to provide service to UEs 115 located indoors. Transmissions using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) than transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0083] The wireless communication system 100 may also operate in a super high frequency (SHF) zone using a frequency band from 3 GHz to 30 GHz (also known as a centimeter band) or in an extremely high frequency (EHF) zone of a spectrum (e.g., from 30 GHz to 300 GHz) (also known as a millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between UE 115 and base station 105, and the EHF antenna of the corresponding device may be smaller and more closely spaced than the UHF antenna. In some examples, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and a shorter range than SHF or UHF transmissions. The technology disclosed herein may be adopted across transmissions using one or more different frequency zones, and the use of frequency bands specified across these frequency zones may vary by country or regulatory agency.

[0084] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ licensed 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 an unlicensed radio frequency spectrum band, devices (such as base stations 105 and UEs 115) may employ carrier sensing for conflict detection and avoidance. In some examples, operations in an unlicensed band may be based on a carrier aggregation configuration (e.g., LAA) in coordination with component carriers operating in a licensed band. Operations in an unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among others.

[0085] The base station 105 or UE 115 may be equipped with multiple antennas, which can be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located in one or more antenna arrays or antenna panels that can 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, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having antenna ports of several rows and columns that the base station 105 can use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted via the antenna ports.

[0086] 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 signals communicated via antenna elements of an antenna array so that some signals propagating at a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0087] The base station 105 or the UE 115 may use beam sweeping techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by the base station 105 in different directions. For example, the base station 105 may transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used (e.g., by a transmitting device (such as the base station 105) or a receiving device (such as the UE 115)) to identify a beam direction used by the base station 105 for later transmission or reception.

[0088] Some signals, such as data signals associated with a particular recipient device, may be transmitted by base station 105 in a single beam direction, e.g., a direction associated with a recipient device, such as UE 115. In some examples, a beam direction associated with transmissions along a single beam direction may be determined based on signals transmitted in one or more beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions and may report to base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0089] In some examples, transmission 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 the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may transmit a reference signal that may be precoded or unprecoded (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)). 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 by base station 105 in one or more directions, UE 115 may use similar techniques to transmit signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115) or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0090] A receiving device (e.g., UE 115) may try multiple reception configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a base station 105. For example, the receiving device may try multiple reception directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, 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 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 reception configurations or reception directions. In some examples, the receiving device may use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). The single reception configuration may be aligned on a beam direction determined based on listening according to different reception configuration directions (e.g., a beam direction determined to have the highest signal strength, the highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0091] In some cases, according to various techniques as discussed herein, when performing an initial access procedure, the base station 105 and the UE 115 may use multiple transmissions to refine beams for subsequent portions of the access procedure. In some cases, the UE 115 may transmit a random access request to the base station 105, and in response, the base station 106 may transmit a PDCCH order to the UE 115. The PDCCH order may indicate that the UE 115 is to transmit one or more modified random access requests to the base station 105.

[0092] In some cases, the ROs used to transmit the initial random access request and the modified random access request may each be associated with the same SSB. In some cases, a first preamble subset may be used for the initial random access request, and a second preamble subset may be used for the modified random access request, and the initial and modified random access requests may be distinguished based on the associated preamble sequence. In some cases, a separate RO set may be configured for the modified random access request that is separate from the initial RO set for the initial random access request. In some cases, the RO for the modified random access request may not be associated with a specific SSB, and such RO may be identified based on one or more configured parameters, which may be triggered by a PDCCH command.

[0093] The base station 105 may monitor the one or more modified random access requests using different beamforming parameters to determine a refined beam to be used for subsequent transmissions in the random access procedure. The base station 105 may then transmit a random access response to the UE 115 using the refined beam and complete the access procedure. The refined beam may provide more reliable reception of the random access response at the UE 115 and thereby improve the reliability and efficiency of communications.

[0094] Figure 2 An example of a wireless communication system 200 that supports beam refinement techniques for random access communications according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100. The wireless communication system 200 may include a base station 105-a and a UE 115-a, which may be referenced Figure 1 Examples of corresponding devices described. The base station 105-a and the UE 115-a can communicate using one or more directional beams. In the wireless communication system 200, a transmitter (e.g., a base station 105-a) can engage in beam sweeping operations to establish an active beam pair link with a receiver (e.g., a UE 115-a) that can be used for downlink communication 205 and uplink communication 210.

[0095] In some examples, the base station 105-a may engage in a beam sweeping operation to establish an active transmit beam with the UE 115-a. For example, the base station 105-a may transmit relatively wide shaped beams that may be transmitted toward different sectors or geographic directions. In some cases, each wide shaped beam may be associated with an SSB, where synchronization signals (e.g., primary synchronization signal (PSS) and secondary synchronization signal (SSS)) and physical broadcast channel (PBCH) transmissions may be transmitted in corresponding beam directions. In some cases, the wide shaped beam may not be narrow enough or have sufficient beamforming gain to provide reliable communication between the UE 115-a and the base station 105-a, and using such a relatively wide beam for a random access response may not result in reliable successful reception at the UE 115-a. Therefore, it may be beneficial to have the base station 105-a and the UE 115-a use beam refinement to generate a narrower beamformed signal (which may have a narrower coverage area but a higher gain) that can be used to communicate a random access response.

[0096] In some cases, the SSB may indicate uplink transmission resources that the UE 115-a can use for random access transmission (e.g., uplink RO resources associated with the SSB). In some cases, the base station 105-a may provide other information (e.g., RACH resources and / or preamble index subsets) that may be configured by a set of parameters in a master information block (MIB), a system information block (SIB), remaining minimum system information (RMSI), or a combination thereof. In some cases, the random access transmission may be a random access request 215 (e.g., RACH message 1 (MSG1)), which may indicate that the UE 115-a has uplink data to transmit or that the UE 115-a desires to establish a connection with the base station 105-a.

[0097] The base station 105-a may receive the random access request 215 and determine to transmit a PDCCH command 220, which may be an example of a control channel command or MSG2' as discussed herein. In some cases, the PDCCH command 220 is a compressed PDCCH command relative to a PDCCH command that may be used in an existing deployment (e.g., for triggering a connected mode UE to send a random access request for handover or timing advance recovery (i.e., based on DCI 1_0 scrambled with a C-RNTI (identified by a full 0FDRA)). Such existing PDCCH commands may have redundant fields to allow alignment with normal DCI 1_0 to avoid UEs decoding different DCI lengths.

[0098] In some cases, the RO used to transmit the random access request 215 may be associated with a particular SSB so that a UE 115-a that determines that the particular SSB is a preferred SSB may use the associated RO to transmit the random access request 215. Based on the reception of the PDCCH order 220, the UE 115-a may then transmit the one or more modified requests 225, which may be an example of a beam refinement signal or MSG1' as discussed herein. In some cases, the one or more modified requests 225 may be transmitted using a set of resources, parameters, or a combination thereof. In some cases, the same RO associated with the selected SSB may be used for both the random access request 215 and the modified request 225. In such cases, a first preamble subset may be used for the random access request 215, and a second preamble subset may be used for the modified request 225, and the initial and modified random access requests may be distinguished based on the associated preamble sequence. In some cases, a separate RO set may be configured for the modified request 225 that is separate from the initial RO set used for the random access request 215. In some cases, the RO for the modified request 225 may not be associated with a particular SSB, and such RO may be identified based on one or more configured parameters that may be triggered by the PDCCH command 220 (i.e., the exact location of the RO is determined based on the PDCCH command 220). According to various aspects of the present disclosure, techniques for providing resources and / or preambles for modified requests are discussed. In addition, techniques for avoiding resource conflicts (e.g., when multiple UEs are mapped to the same resources and the same preamble sequence for MSG1' transmission) and for avoiding beam conflicts (e.g., when multiple UEs using different beams are mapped to the same time domain resources for MSG1' transmission so that the base station 105-a cannot receive them simultaneously).

[0099] After transmitting the PDCCH command 220, the base station 105-a may monitor the modified request 225 at the identified uplink resource using one or more relatively narrow beams that are narrower than the beam associated with the SSB, and identify the refined beam based on the monitoring. The base station 105-a may then use the refined beam to transmit a random access response 230 to the UE 115-a. Since the random access response 230 is transmitted using the refined beam, the UE 115-a has a higher probability of successfully receiving the random access response 230. Accordingly, such techniques may improve network efficiency and reliability by providing a faster and more reliable initial access procedure. After decoding the random access response 230, the UE 115-a may transmit a UE identification 235 in a MSG3 transmission, and the random access procedure may proceed according to the established random access technology to complete the connection establishment between the UE 115-a and the base station 105-a.

[0100] Figure 3 An example of uplink and downlink transmission 300 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is illustrated. In some examples, uplink and downlink signaling 300 can implement aspects of wireless communication systems 100 or 200. In this example, base station 105-b (which can be Figure 1 or Figure 2 105) may transmit multiple wide beam downlink transmissions in beam sweeping operation 305, which may be detected at UE 115-b. In some cases, each wide beam may be transmitted in SSB 310. Figure 4 In the example of , the first SSB 310 - a may be the SSB for the first beam, and so on, up to the nth SSB 310 - n for the nth beam.

[0101] In some cases, within each SSB 310, the base station 105-b may transmit synchronization information in the form of primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH) transmissions. In some cases, each SSB 310 may have an associated uplink transmission resource 315 (e.g., a first RACH resource), and a random access request received in a particular RACH resource may indicate the associated SSB 310 selected by the UE 115-b. The UE 115-b in this example may monitor the received signals during the beam sweeping operation 305 and determine that the first SSB 310-a has a higher gain (e.g., a higher RSRP) than the other SSBs 310, and may determine the associated first RACH resource for transmitting MSG1 315. In some examples, as discussed herein, the first SSB can have a different subset of RACH resources, where the first subset of RACH resources can be used to indicate that UE 115-b supports beam refinement in random access, and the second subset of RACH resources can be used to indicate that UE 115-b does not support beam refinement in random access or does not need such beam refinement (e.g., when the signal quality of the signal from the first SSB 310-a is above a threshold). In other cases, as discussed herein, a different random access preamble code for MSG1 315 can be selected to provide such an indication of beam refinement capability.

[0102] The base station 105-b may receive MSG1 315 and determine to transmit a PDCCH command in MSG2'320 to trigger UE115-b to subsequently transmit a modified random access request in MSG1'325. The base station 105-b may monitor the MSG1'325 transmission using beamforming parameters associated with one or more refined beams to determine the refined beam to be used for subsequent random access communications. In some cases, the resources or preambles used for the MSG1'325 transmission may be determined in accordance with various aspects of the present disclosure, and such resources may be referred to as RO'. Optionally, the base station 105-b may transmit a second PDCCH command in MSG2'330 to trigger a second MSG1'335, which may be used for further beam refinement, and such a process may continue for one or more further PDCCH commands that are responsive transmissions. The base station 105-b may perform a beam refinement procedure while monitoring the MSG1' transmission, such as by determining a refined beam using a plurality of receive beam parameters. The base station 105-b may transmit MSG2 340 using the refined beam. The UE 115-b may receive MSG2 340 and transmit MSG3 345, which may be followed by MSG4 350 from the base station 105-b, as well as a downlink transmission 355 and an uplink transmission 360.

[0103] Figure 4 An example of a random access opportunity 400 supporting beam refinement techniques for random access communications according to aspects of the present disclosure is illustrated. In some examples, the random access opportunity 400 can be implemented in aspects of the wireless communication system 100 or 200. In this example, a UE (e.g., Figure 1 , Figure 2 or Figure 3 The UE 115) may transmit a random access request or MSG1 and, in response thereto, receive a control channel command or MSG2' indicating that the UE is to transmit a modified random access request or MSG1' which may be used as a beam refinement signal at the base station.

[0104] In some cases, the resources used for both MSG1 and MSG1' transmissions may be selected from a RO set 405 established for a random access request from a UE. As discussed herein, an SSB may have an associated RO for a random access request, and each RO set 405 may have several different individual ROs 410 associated with a particular SSB. The RO set 405 may be configured by the base station in periodic resources and indicated to the UE (e.g., in the MIB, SIB, PBCH, RMSI, etc.). Figure 4In the example of , MSG1 and MSG1' transmissions associated with the selected SSB may share the same RO 410. In such a case, in response to receiving MSG2', the UE may transmit MSG1' in the next one or more ROs 410 corresponding to the same SSB as the original MSG1 transmission.

[0105] In this example, MSG1 and MSG1' transmissions from different UEs may be separated by providing different subsets of preamble sequences for MSG1 and MSG1' transmissions in the same RO 410. In this example, a first subset of preamble indices 420 may be provided for MSG1 transmissions, and a second set of preamble indices 415 may be provided for MSG1' transmissions. Such techniques may use relatively few system resources, but may reduce the number of preamble sequences available for MSG1 transmissions, and also result in a relatively long time period for transmitting beam refinement signals because ROs 410 for the same SSB may be spaced apart in a random access configuration. Furthermore, in the case of transmitting multiple repetitions of MSG1', such time may be extended to provide multiple copies of the message. Such shared resources for MSG1 and MSG1' transmission time durations may be desirable in various deployments where separate system resources for MSG1 may not be available or desired to be configured. In other situations, such as in Figures 5 to 7 As explained in , different resources (referred to as RO') separate from the RO resources configured for random access may be configured.

[0106] Figure 5 An example of a random access opportunity 500 supporting beam refinement techniques for random access communications according to aspects of the present disclosure is illustrated. In some examples, the random access opportunity 500 can be implemented in aspects of the wireless communication system 100 or 200. In this example, a UE (e.g., Figure 1 , Figure 2 or Figure 3 The UE 115) may transmit a random access request or MSG1 and, in response thereto, receive a control channel command or MSG2' indicating that the UE is to transmit a modified random access request or MSG1' which may be used as a beam refinement signal at the base station.

[0107] In this example, according to the random access configuration provided by the base station, MSG1 transmissions may be transmitted in a RO 515 for MSG1, which is in a RO set 505 for MSG1. Resources for MSG1' transmissions may be configured in separate RO' 520 resources, which may be in a RO' set 510. In this example, multiple RO sets 505 may be configured in a periodic manner to provide the illustrated first RO set 505-a to fourth RO set 505-d. Similarly, multiple RO' sets 510 may be configured in a periodic manner to provide the illustrated first RO' set 510-a to fourth RO' set 510-d. Although four RO and RO' resource sets are illustrated, it should be understood that more or fewer sets may be configured for either or both of the RO and RO'.

[0108] In some cases, the resources used for the RO' set 510 can be configured separately from the random access configuration that provides these RO resources. For example, the RO' set 510 can be configured by the base station in RRC signaling, which can provide configuration information indicating the time resources, frequency resources, or a combination thereof used for MSG1' transmission. In addition, in some cases, such configuration information can indicate how many repetitions of MSG1' will be transmitted. In other cases, such configuration can be provided in other signaling, such as RMSI other system information alone or in combination with the configured RRC signaling. In some cases, the location of the RO' set 510 can be periodic and have the same or different periodicity as the RO set 505. In addition, in some cases, the RO' set 510 can be associated with an SSB, or can be unassociated with a specific SSB, such as in Figure 6 This is explained in the example of .

[0109] Figure 6 An example of a random access opportunity 600 supporting beam refinement techniques for random access communications according to aspects of the present disclosure is illustrated. In some examples, the random access opportunity 600 can be implemented in aspects of the wireless communication system 100 or 200. In this example, again, a UE (e.g., Figure 1 , Figure 2 or Figure 3 The UE 115) may transmit a random access request or MSG1 and, in response thereto, receive a control channel command or MSG2' indicating that the UE is to transmit a modified random access request or MSG1' which may be used as a beam refinement signal at the base station.

[0110] As reference Figure 5As discussed, in some cases, according to the random access configuration provided by the base station, the MSG1 transmission may be transmitted in the RO 605 for MSG1 (e.g., it may be in the RO set for MSG1). In addition, the resources for MSG1' transmission may be configured in a separate RO' 610 resource (e.g., it may be in the RO' set). In some cases, as illustrated in the first example 615, both the RO 605 and RO' 605 for the MSG1 and MSG1' transmissions of the UE may be mapped to the same SSB. In other cases, as illustrated in the second example 620, the RO' 610 may not be associated with a specific SSB.

[0111] In the first example 615, both the first RO 605-a and the second RO 605-b can be associated with the first SSB. Therefore, a UE using the first RO 605-a or the second RO 605-b can determine resources for RO' 610 based on the first SSB, and determine that the first RO' 610-a and the second RO' 610-b are available for MSG1' transmission.

[0112] In the second example 620, the third RO 605-c and the fourth RO 605-d may both be associated with the first SSB. However, in this example, the RO' 610 resource may not be associated with the first SSB (or any SSB), and may be configured separately so that the third RO' 610-c, the fourth RO' 610-d, the fifth RO' 610-e, and the sixth RO' 610-f are available for MSG1' transmission. Since the RO' 610 of the second example 60 is not associated with an SSB, the same RO' 610 may be shared by different SSBs. As shown in FIG. Figure 5 As discussed, signaling to configure RO'610 may be provided by the base station in RRC signaling, which may provide configuration information indicating time resources, frequency resources, or a combination thereof for MSG1' transmission. Additionally, in some cases, such configuration information may indicate how many repetitions of MSG1' will be transmitted. In other cases, such configuration may be provided in other signaling, such as RMSI other system information, either alone or in combination with the configured RRC signaling. In some cases, the location of RO'610 may be periodic and have the same or different periodicity as RO 605. Such techniques may allow additional resources for transmitting MSG1', which may allow lower latency for the random access procedure relative to a scenario where the RO is shared for MSG1 and MSG1' transmissions. In a further example, the exact location of the RO resources may not be preconfigured, but may be indicated to the UE based on a control channel command, such as a reference to a UE. Figure 7 discussed.

[0113] Figure 7An example of a triggered random access opportunity for a modified random access request 700 supporting beam refinement techniques for random access communications according to aspects of the present disclosure is illustrated. In some examples, the triggered random access opportunity for the modified random access request 700 can implement aspects of the wireless communication system 100 or 200. In this example, a UE (e.g., Figure 1 , Figure 2 or Figure 3 UE 115) may transmit a random access request or MSG1 710 using RO 705 for MSG1 and receive a control channel command or MSG2' 715 in response thereto, the control channel command or MSG2' 715 indicating that the UE is to transmit a modified random access request or MSG1' 720, which may be used as a beam refinement signal at the base station. In this example, two repetitions of the same MSG1' 720 sequence may be transmitted in a first RO' 725-a instance and a second RO' 725-b instance, the first RO' 725-a instance and the second RO' 725-b instance being illustrated in consecutive resources, but in other cases may be illustrated in resources that are not consecutive in time and / or frequency.

[0114] In this example, the base station can dynamically trigger a separate RO' 725 for MSG1' 720 transmission via MSG2' 715, where the RO' 725 is separate from the RO 705 for MSG1 transmission 710. In some cases, the base station can configure (e.g., via RRC signaling) the time and / or frequency resources, number of repetitions, etc. for MSG1' 720 transmission. Such configuration can be common to all beams (i.e., there is no beam information for the configured RO' 725 resources), and the MSG1' 720 transmission can use the same beam as the MSG1 710 transmission. The configuration information (e.g., RRC configuration) in such a case therefore does not provide information about where the RO' 725 is, but rather defines the structure of the RO' 725, and the exact location (i.e., time / frequency resources) of the RO' 725 is determined based on the MSG2' 715 transmission. Thus, MSG2' 715 may be viewed as an UL grant for MSG1' transmission 720 at pre-configured resources, where MSG2' 715 provides the exact location of the RO' 725 resources. In some cases, the time domain resources for RO' 725 may be configured relative to the MSG2' 715 transmission, such as at a fixed offset from the MSG2' 715 timing. In some cases, MSG2' 715 may also include one or more bits that may provide the base station with greater flexibility to identify the resources for RO' 725 (e.g., the base station may select a timing offset from two or four available offsets based on the number of bits).

[0115] In some cases, for Figures 4 to 7 In an example of any of the above, RO and RO' resources, preambles, or any combination thereof may be configured to provide unambiguous identification of resources and parameters for MSG1' communication. In some cases, for a given SSB, a corresponding RO set (time domain and frequency domain) and a preamble index set may be configured, and the UE will select one of them for MSG1 transmission. Given MSG1 resources (RO and preamble index), MSG1' resources (RO' and preamble index) may be mapped according to the techniques provided herein. In some cases, a hash function may be configured from the RO index for MSG1 transmission, the preamble index for MSG1, or a combination thereof to the RO' index for MSG1', the preamble index, or a combination thereof. In some cases, the base station may have the flexibility to provide a control value for one or more adjustments to the hash function to provide an RO' resource that can be selected by the base station.

[0116] In some cases, the hash function may be based on the MSG1 resource set (e.g., the number of preambles for MSG1 in RO and each RO), the MSG1' resource set (e.g., the number of preambles for MSG1' in RO' and each RO'). In such cases, the inputs to the hash function may be: the preamble index for MSG1, the RO index for MSG1, and a base station control value, which may be a bit value that allows selection from a resource set (e.g., similar to the PUCCH Resource Indicator (PRI) mechanism established in NR). The output of the hash function may be the frequency domain RO' index for MSG1', the preamble index for MSG1', which may be the same for each repetition or different for each repetition in the case where repetitions of MSG1' are configured. In some cases, a group hopping algorithm may be used to avoid collisions of multiple repetitions of MSG1' from different UEs.

[0117] In some cases, the time domain resource used for RO' may not be a hash function, but determined by the timing of MSG2' transmission, the available RO' applicable to MSG1' transmission (e.g., RO' corresponding to the same SSB as MSG1), the number of repetitions, etc. In some cases, the starting RO index for MSG1' transmission may be associated with the timing of MSG2' transmission. For example, the starting RO index for MSG1' transmission may be the first time domain RO opportunity corresponding to the same SSB index at a certain time line after receiving MSG2' (e.g., X symbols after the last symbol of the PDCCH carrying MSG2'). In some cases, MSG2' may further include one or more bits or otherwise provide an indication (e.g., based on a shift applied to a bit sequence used in MSG2' transmission) to indicate a further offset for controlling the first RO used for MSG1' transmission.

[0118] In the case where MSG1 and MSG1' use the same RO resources, such as Figure 4 As explained in , the hash function can provide a mapping between preambles for MSG1' based on the MSG1 preamble, while the RO sets for MSG1 and MSG1' are the same. In such a case, for MSG1' transmission, the effective RO' is the SSB that corresponds to the same original RO for MSG1 after MSG2' reception. In the case where a separate RO' associated with an SSB is configured, such as in Figure 6 As illustrated in the first example of , for each SSB, there is a set of ROs for MSG1 and another set of ROs for MSG1'. In such a case, for a MSG1' transmission, the effective RO' may be the RO' that corresponds to the same SSB as the original RO for MSG1 after reception by MSG2', and the preamble may be mapped based on the hash function, or the same preamble used for MSG1 may be used for MSG1'. In the case where the RO' is not associated with a specific SSB (e.g., as Figure 6 ), for each SSB, there is a set of ROs for MSG1, and there is a common set of ROs for MSG1', where the starting RO index and preamble for MSG1' can be selected from the common set of ROs based on a hash function, and where the RO' can be further selected by MSG2'. In the case where MSG2' acts as a grant or trigger to indicate resources for RO, additional control can be provided in MSG2' to control the first RO' used for MSG1' transmission (for example, to add further delay, such as in the case where the first RO' has been assigned to MSG1' of another UE and cannot be shared with MSG1' of a different UE). In some cases, the base station can also select the starting index for RO' based on when MSG2 is transmitted.

[0119] Figure 8 An example of a process flow 800 supporting beam refinement techniques for random access communications in accordance with various aspects of the present disclosure is illustrated. In some examples, the process flow 800 may implement aspects of the wireless communication system 100 or 200. The process flow 800 may be implemented by a UE 115-c and a base station 105-c, as described herein. The following alternative examples may be implemented, in which some of the steps are performed in a different order than described or not performed at all. In some cases, the steps may include additional features not mentioned below, or further steps may be added.

[0120] At 805, the base station 105-c may transmit one or more SSB transmissions. In some cases, the SSB transmission may be a beam swept transmission of multiple SSBs transmitted in corresponding beam directions, including synchronization signals (e.g., PSS and SSS) and PBCH transmissions. In some cases, the SSB may indicate associated uplink transmission resources (e.g., RO) that the UE 115-c may use for random access transmissions.

[0121] At 810, UE 115-b may identify RACH resources for a random access request. As discussed herein, in some cases, a RACH resource (eg, RO) may be associated with a particular SSB selected at UE 115-b based on received signal strength.

[0122] At 815, UE 115-b may select a particular RACH resource (e.g., RO) based on one or more reference signal measurements, UE capabilities (e.g., based on the ability of UE 115-c to receive MSG2' and transmit MSG1' in response thereto), or any combination thereof. At 820, based on the selected RACH resource, UE 115-c may transmit MSG1.

[0123] At 825, the base station 105-c may determine that a PDCCH command is to be transmitted to the UE 115-c. In some cases, the base station 105-c may make such a determination based on available random access resources, signal strength of the MSG1 transmission, etc. In this example, the base station 105-c determines that a PDCCH command is to be transmitted, and transmits the PDCCH command (e.g., MSG2') to the UE 115-c at 830.

[0124] At 835, UE 115-c may detect the PDCCH command and determine to transmit a modified random access request (e.g., MSG1') to base station 105-c, which may be used for beam refinement. UE 115-c may determine RO' resources for MSG1' transmission based on the PDCCH command according to the techniques discussed herein. At 840, UE 115-c may transmit MSG1' to base station 105-c.

[0125] At 845, the base station 105-c may monitor the MSG1′ transmission using the two or more receive beams to determine beam refinements for use in subsequent communications with the UE 115-c. In some cases, the base station 105-c may determine the beam refinements based on which of the two or more receive beams provides a better signal strength for receiving the MSG1′ transmission.

[0126] At 850, the base station 105-c may transmit a regular MSG2 to the UE 115-c. The MSG2 transmission may use a refined transmit beam determined based on the beam refinement performed at the base station 105-c. At 855, the UE 115-c may transmit MSG3 according to the established RACH technique, followed by a MSG4 transmission from the base station 105-c at 860, and uplink / downlink communications between the UE 115-c and the base station 105-c at 865.

[0127] Fig. 9 A block diagram 900 of a device 905 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The device 905 may be an example of aspects of a UE 115 as described herein. The device 905 may include a receiver 910, a communication manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0128] 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 beam refinement techniques for random access communications, etc.). The information may be passed to other components of the device 905. The receiver 910 may be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The receiver 910 may utilize a single antenna or a collection of antennas.

[0129] The communication manager 915 may transmit an initial random access request to a base station to establish a wireless connection with the base station, receive a control channel command from the base station in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, transmit the one or more modified random access requests using the determined resource set, and receive a random access response from the base station in response to the one or more modified random access requests. The communication manager 915 may be an example of aspects of the communication manager 1210 described herein.

[0130] The communication manager 915 may be implemented as described herein to achieve one or more potential advantages. An implementation may allow the device 905 to perform a random access procedure with a higher probability of success, which may provide enhanced efficiency and reduced access time associated with the random access procedure. In addition, various implementations may allow the device 905 to enhance the reliability of communications, increase throughput, and enhance user experience while reducing power consumption associated with retransmissions or additional random access attempts, among other advantages.

[0131] The communication manager 915 or its subcomponents may be implemented in hardware, in 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 communication manager 915 or its subcomponents may be performed by a general purpose processor, a DSP, an application specific integrated circuit (ASIC), an FPGA or other programmable logic device designed to perform the functions described in the present disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0132] The communication manager 915 or its subcomponents may be physically located at various locations, including being distributed such that portions of functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 915 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 915 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0133] The transmitter 920 may transmit signals generated by other components of the device 905. In some examples, the transmitter 920 may be co-located with the receiver 910 in a transceiver module. For example, the transmitter 920 may be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The transmitter 920 may utilize a single antenna or a collection of antennas.

[0134] Fig.10 A block diagram 1000 of a device 1005 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The device 1005 may be an example of aspects of the device 905 or UE 115 as described herein. The device 1005 may include a receiver 1010, a communication manager 1015, and a transmitter 1045. The device 1005 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0135] 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 beam refinement techniques for random access communications, etc.). The information may be passed to other components of the device 1005. The receiver 1010 may be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The receiver 1010 may utilize a single antenna or a collection of antennas.

[0136] The communication manager 1015 may be an example of aspects of the communication manager 915 as described herein. The communication manager 1015 may include a random access request manager 1020, a control channel command manager 1025, a resource manager 1030, a beam refinement manager 1035, and a random access response manager 1040. The communication manager 1015 may be an example of aspects of the communication manager 1210 described herein.

[0137] The random access request manager 1020 may transmit, to a base station, an initial random access request to establish a wireless connection with the base station.

[0138] The control channel command manager 1025 may receive a control channel command from a base station in response to an initial random access request.

[0139] The resource manager 1030 may determine a set of resources for the one or more modified random access requests based on the control channel command.

[0140] The beam refinement manager 1035 may transmit the one or more modified random access requests using the determined set of resources.

[0141] The random access response manager 1040 may receive a random access response from the base station in response to the one or more modified random access requests.

[0142] The transmitter 1045 can transmit signals generated by other components of the device 1005. In some examples, the transmitter 1045 can be co-located with the receiver 1010 in a transceiver module. Fig.12 Examples of various aspects of the described transceiver 1220. The transmitter 1045 may utilize a single antenna or a collection of antennas.

[0143] Fig.11 A block diagram 1100 of a communication manager 1105 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The communication manager 1105 may be an example of aspects of the communication manager 915, the communication manager 1015, or the communication manager 1210 described herein. The communication manager 1105 may include a random access request manager 1110, a control channel command manager 1115, a resource manager 1120, a beam refinement manager 1125, a random access response manager 1130, a random access parameter manager 1135, and a preamble sequence manager 1140. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0144] The random access request manager 1110 may transmit, to a base station, an initial random access request for establishing a wireless connection with the base station.

[0145] The control channel command manager 1115 may receive a control channel command from a base station in response to an initial random access request. In some cases, the control channel command acts as an uplink grant for the one or more modified random access requests using the resource set. In some cases, the resource set is determined based on the location of the control channel command. In some cases, the time domain location of the resource set is based on a time offset from the control channel command. In some cases, the time domain location of the resource set is based on a fixed time offset from the control channel command or a time offset indicated by one or more bits in the control channel command.

[0146] The resource manager 1120 may determine a resource set for one or more modified random access requests based on the control channel command. In some examples, the resource manager 1120 may identify a resource set in a subsequent random access opportunity of a first random access opportunity based on the control channel command, wherein the subsequent random access opportunity is associated with the same synchronization signal block (SSB) as the first random access opportunity.

[0147] In some examples, the resource manager 1120 may identify a resource set for the one or more modified random access requests based on a second random access opportunity configuration different from the first random access opportunity configuration of the initial random access request. In some examples, the resource manager 1120 may identify the resource set based on an indication provided by a control channel command.

[0148] In some examples, the resource manager 1120 may receive in RRC signaling a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity. In some examples, the resource manager 1120 may select a set of resources from a configured number of available resources for transmitting the one or more modified random access requests, and wherein the selection is based on one or more of the timing of the control channel command or an offset indicated by the control channel command.

[0149] In some examples, the resource manager 1120 may identify a set of configured parameters for random access opportunities associated with the one or more modified random access requests. In some examples, the resource manager 1120 may determine the location of the resource set based on one or more of the set of configured parameters and the timing of the control channel command or the offset indicated by the control channel command.

[0150] In some cases, the second random access opportunity configuration is received in RRC signaling from the base station. In some cases, the second random access opportunity configuration includes configuration parameters for one or more of: a time resource for the second random access opportunity, a frequency resource for the second random access opportunity, a number of repetitions of the modified random access request to be transmitted, or any combination thereof.

[0151] In some cases, a periodic resource set is provided for the one or more modified random access requests. In some cases, the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for the initial random access request. In some cases, a set of different random access opportunities for transmitting the modified random access request is configured for each SSB in a set of different SSBs.

[0152] In some cases, the second random access opportunity configuration is not associated with any synchronization signal block (SSB). In some cases, a set of different random access opportunities for transmitting a modified random access request is shared by two or more different SSBs. In some cases, RRC signaling provides one or more of a time resource or a frequency resource for a random access opportunity, a number of repetitions of the one or more modified random access requests, or any combination thereof.

[0153] In some cases, the function for determining the random access opportunity is based on a control value provided in a control channel command. In some cases, the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof.

[0154] In some cases, a starting random access opportunity index associated with the resource set is determined based on a time domain position of a control channel command. In some cases, a starting time domain resource of the resource set is based on an initial time domain resource corresponding to a synchronization signal block (SSB) index associated with an initial random access request and a fixed or signaled time domain offset from a second time domain resource of the control channel command. In some cases, the resource set includes resources in a second random access opportunity, the resources of the second random access opportunity being determined as a function of a first random access opportunity associated with the initial random access request.

[0155] The beam refinement manager 1125 may transmit the one or more modified random access requests using the determined resource set. The random access response manager 1130 may receive a random access response from the base station in response to the one or more modified random access requests. The random access parameter manager 1135 may identify one or more parameters for the one or more modified random access requests based on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

[0156] The preamble sequence manager 1140 may select a first preamble sequence for the one or more modified random access requests from a first preamble sequence subset associated with a first random access opportunity, wherein the first preamble sequence subset does not overlap with a second preamble sequence subset available for an initial random access request associated with the first random access opportunity. In some examples, the preamble sequence manager 1140 may determine the second preamble for the one or more modified random access requests as a function of the first random access opportunity associated with the initial random access request, the first preamble of the initial random access request, or any combination thereof. In some examples, the preamble sequence manager 1140 may determine the second random access preamble for the one or more modified random access requests as a function of the first random access preamble for the initial random access request. In some cases, the same preamble is used for each of the two or more repetitions of the modified random access request, or a different preamble is used for each of the two or more repetitions of the modified random access request based on a frequency hopping algorithm.

[0157] Fig.12 A diagram of a system 1200 including a device 1205 supporting beam refinement techniques for random access communications according to various aspects of the present disclosure is shown. The device 1205 may be an example of a device 905, a device 1005, or a UE 115 as described herein or include components of these devices. The device 1205 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a communication manager 1210, an I / O controller 1215, a transceiver 1220, an antenna 1225, a memory 1230, and a processor 1240. These components may be in electronic communication via one or more buses (e.g., a bus 1245).

[0158] The communication manager 1210 may transmit an initial random access request to a base station for establishing a wireless connection with the base station, receive a control channel command from the base station in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, transmit the one or more modified random access requests using the determined resource set, and receive a random access response from the base station in response to the one or more modified random access requests.

[0159] The communication manager 1210 may be implemented as described herein to achieve one or more potential advantages. An implementation may allow the device 1205 to perform a random access procedure with a higher probability of success, which may provide enhanced efficiency and reduced access time associated with the random access procedure. In addition, the implementation may allow the device 1205 to enhance the reliability of communications, increase throughput, and enhance the user experience while reducing power consumption associated with retransmissions or additional random access attempts, among other advantages.

[0160] I / O controller 1215 can manage input and output signals for device 1205. I / O controller 1215 can also manage peripheral devices that are not integrated into device 1205. In some cases, I / O controller 1215 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1215 can utilize an operating system, such as Or another known operating system. In other cases, I / O controller 1215 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 1215 may be implemented as part of a processor. In some cases, a user may interact with device 1205 via I / O controller 1215 or via hardware components controlled by I / O controller 1215.

[0161] The transceiver 1220 may communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1220 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1220 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0162] In some cases, a 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 transmitting or receiving multiple wireless transmissions concurrently.

[0163] Memory 1230 may include RAM and ROM. Memory 1230 may store computer-readable, computer-executable code 1235 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, memory 1230 may include, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0164] 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, processor 1240 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1240. Processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause device 1205 to perform various functions (e.g., functions or tasks supporting beam refinement techniques for random access communications).

[0165] The code 1235 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1235 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 1235 may not be directly executed by the processor 1240, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0166] Fig.13 A block diagram 1300 of a device 1305 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The device 1305 may be an example of aspects of a base station 105 as described herein. The device 1305 may include a receiver 1310, a communication manager 1315, and a transmitter 1320. The device 1305 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0167] Receiver 1310 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 beam refinement techniques for random access communications, etc.). The information may be passed to other components of device 1305. Receiver 1310 may be a reference Fig.16 Examples of various aspects of the described transceiver 1620. The receiver 1310 may utilize a single antenna or a collection of antennas.

[0168] The communication manager 1315 may receive an initial random access request from a UE to establish a wireless connection with a base station, transmit a control channel command to the UE in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, monitor the one or more modified random access requests using the determined resource set, and transmit a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests. The communication manager 1315 may be an example of aspects of the communication manager 1610 described herein.

[0169] The communication manager 1315 or its subcomponents may be implemented in hardware, in 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 communication manager 1315 or its subcomponents may be performed by a general purpose processor, a DSP, an application specific integrated circuit (ASIC), an FPGA or other programmable logic device designed to perform the functions described in this disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0170] The communication manager 1315 or its subcomponents may be physically located at various locations, including being distributed such that portions of functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 1315 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 1315 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0171] Transmitter 1320 may transmit signals generated by other components of device 1305. In some examples, transmitter 1320 may be co-located with receiver 1310 in a transceiver module. For example, transmitter 1320 may be a reference Fig.16 Examples of various aspects of the described transceiver 1620. The transmitter 1320 may utilize a single antenna or a collection of antennas.

[0172] Fig.14A block diagram 1400 of a device 1405 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The device 1405 may be an example of aspects of the device 1305 or base station 105 as described herein. The device 1405 may include a receiver 1410, a communication manager 1415, and a transmitter 1440. The device 1405 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0173] Receiver 1410 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 beam refinement techniques for random access communications, etc.). The information may be passed to other components of device 1405. Receiver 1410 may be a reference Fig.16 Examples of various aspects of the described transceiver 1620. The receiver 1410 may utilize a single antenna or a collection of antennas.

[0174] The communication manager 1415 may be an example of aspects of the communication manager 1315 as described herein. The communication manager 1415 may include a random access request manager 1420, a control channel command manager 1425, a resource manager 1430, and a random access response manager 1435. The communication manager 1415 may be an example of aspects of the communication manager 1610 described herein.

[0175] The random access request manager 1420 may receive an initial random access request from a UE to establish a wireless connection with a base station.

[0176] The control channel command manager 1425 may transmit a control channel command to the UE in response to the initial random access request.

[0177] The resource manager 1430 may determine a resource set for one or more modified random access requests based on the control channel command; and

[0178] The one or more modified random access requests are monitored using the determined set of resources.

[0179] The random access response manager 1435 may transmit a random access response to the UE using one or more beamforming parameters based on measurements associated with the one or more modified random access requests.

[0180] Transmitter 1440 may transmit signals generated by other components of device 1405. In some examples, transmitter 1440 may be co-located with receiver 1410 in a transceiver module. For example, transmitter 1440 may be a reference Fig.16Examples of various aspects of the described transceiver 1620. The transmitter 1440 may utilize a single antenna or a collection of antennas.

[0181] Fig.15 A block diagram 1500 of a communication manager 1505 supporting beam refinement techniques for random access communications in accordance with aspects of the present disclosure is shown. The communication manager 1505 may be an example of aspects of the communication manager 1315, the communication manager 1415, or the communication manager 1610 described herein. The communication manager 1505 may include a random access request manager 1510, a control channel command manager 1515, a resource manager 1520, a random access response manager 1525, and a preamble sequence manager 1530. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0182] The random access request manager 1510 may receive an initial random access request from a UE to establish a wireless connection with a base station.

[0183] The control channel command manager 1515 may transmit a control channel command to the UE in response to the initial random access request. In some examples, the control channel command manager 1515 may provide an indication identifying the resource set to the UE in the control channel command. In some cases, the control channel command acts as an uplink grant for the one or more modified random access requests using the resource set. In some cases, the resource set is determined based on the location of the control channel command. In some cases, the time domain location of the resource set is based on a time offset from the control channel command. In some cases, the time domain location of the resource set is based on a fixed time offset from the control channel command or a time offset indicated by one or more bits in the control channel command.

[0184] The resource manager 1520 may determine a resource set for one or more modified random access requests based on the control channel command. In some examples, the resource manager 1520 may monitor the one or more modified random access requests using the determined resource set. In some examples, the resource manager 1520 may identify one or more parameters for the one or more modified random access requests based on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

[0185] In some examples, the resource manager 1520 may identify a resource set in a subsequent random access opportunity of the first random access opportunity based on a control channel command, wherein the subsequent random access opportunity is associated with a synchronization signal block (SSB) that is the same as the first random access opportunity. In some examples, the resource manager 1520 may identify a resource set for the one or more modified random access requests based on a second random access opportunity configuration that is different from the first random access opportunity configuration of the initial random access request.

[0186] In some examples, the resource manager 1520 may transmit a second random access opportunity configuration to the UE in RRC signaling. In some examples, the resource manager 1520 may transmit a parameter set associated with a random access opportunity for transmitting the one or more modified random access requests in RRC signaling, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity.

[0187] In some examples, the resource manager 1520 can configure a number of available resources for the UE for transmitting the one or more modified random access requests, and wherein the resource set is selected from the number of available resources based on the timing of the control channel command or one or more of the offsets indicated by the control channel command.

[0188] In some examples, the resource manager 1520 may configure a set of parameters for random access opportunities associated with the one or more modified random access requests. In some examples, the resource manager 1520 may determine the location of the resource set based on the configured set of parameters and one or more of the timing of the control channel command or the offset indicated by the control channel command. In some cases, the second random access opportunity configuration includes parameters for one or more of: a time resource for the second random access opportunity, a frequency resource for the second random access opportunity, a number of repetitions of the modified random access request to be transmitted, or any combination thereof. In some cases, a periodic resource set is provided for the one or more modified random access requests.

[0189] In some cases, the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for an initial random access request. In some cases, a set of different random access opportunities for transmitting a modified random access request is configured for each SSB in a set of different SSBs. In some cases, the second random access opportunity configuration is not associated with any synchronization signal block (SSB). In some cases, the set of different random access opportunities for transmitting a modified random access request is shared by two or more different SSBs.

[0190] In some cases, RRC signaling provides one or more of a time resource or a frequency resource for a random access opportunity, a number of repetitions of the one or more modified random access requests, or any combination thereof. In some cases, a starting random access opportunity index associated with the resource set is determined based on a time domain position of a control channel command. In some cases, a starting time domain resource of the resource set is based on an initial time domain resource corresponding to a synchronization signal block (SSB) index associated with an initial random access request and a fixed or signaled time domain offset of a second time domain resource of a control channel command. In some cases, the resource set includes resources in a second random access opportunity, the second random access opportunity being determined as a function of a first random access opportunity associated with the initial random access request.

[0191] The random access response manager 1525 may transmit a random access response to the UE using one or more beamforming parameters based on measurements associated with the one or more modified random access requests.

[0192] The preamble sequence manager 1530 may determine that the one or more modified random access requests are associated with the UE based on the one or more modified random access requests having a preamble that is a function of a first random access opportunity associated with an initial random access request, a first preamble of the initial random access request, or any combination thereof. In some cases, a first preamble sequence subset for a first random access opportunity is associated with the initial random access request message, and a second preamble sequence subset for the first random access opportunity is associated with the modified random access message, wherein the first preamble sequence subset does not overlap with the second preamble sequence subset. In some cases, the function is further based on a control value provided in a control channel command.

[0193] In some cases, the second random access preamble used for the one or more modified random access requests is a function of the first random access preamble used for the initial random access request. In some cases, the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof. In some cases, the same preamble is used for each of two or more repetitions of the modified random access request, or a different preamble is used for each of two or more repetitions of the modified random access request based on a frequency hopping algorithm.

[0194] Fig.16A diagram of a system 1600 including a device 1605 supporting beam refinement techniques for random access communications according to aspects of the present disclosure is shown. The device 1605 may be an example of a device 1305, a device 1405, or a base station 105 as described herein or include components of the above devices. The device 1605 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a communication manager 1610, a network communication manager 1615, a transceiver 1620, an antenna 1625, a memory 1630, a processor 1640, and an inter-station communication manager 1645. These components may be in electronic communication via one or more buses (e.g., bus 1650).

[0195] The communication manager 1610 may receive an initial random access request from a UE to establish a wireless connection with a base station, transmit a control channel command to the UE in response to the initial random access request, determine a resource set for one or more modified random access requests based on the control channel command, monitor the one or more modified random access requests using the determined resource set, and transmit a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based on measurements associated with the one or more modified random access requests.

[0196] The network communications manager 1615 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1615 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0197] The transceiver 1620 may communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1620 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1620 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0198] In some cases, a wireless device may include a single antenna 1625. However, in some cases, the device may have more than one antenna 1625, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0199] Memory 1630 may include RAM, ROM, or a combination thereof. Memory 1630 may store computer readable code 1635 including instructions that, when executed by a processor (e.g., processor 1640), cause the device to perform various functions described herein. In some cases, memory 1630 may include, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0200] Processor 1640 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, processor 1640 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into processor 1640. Processor 1640 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1630) to cause device 1605 to perform various functions (e.g., functions or tasks supporting beam refinement techniques for random access communications).

[0201] The inter-site communication manager 1645 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-site communication manager 1645 may coordinate the scheduling of transmissions to UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-site communication manager 1645 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0202] The code 1635 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1635 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 1635 may not be directly executed by the processor 1640, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0203] Fig.17 1700 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 1700 may be implemented by the UE 115 or its components as described herein. For example, the operations of the method 1700 may be implemented by the UE 115 or its components as described herein. Figures 9 to 12 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0204] At 1705, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. 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 as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0205] At 1710, the UE may receive a control channel command from a base station in response to an initial random access request. 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 as described with reference to Figures 9 to 12 The control channel command manager described is executed.

[0206] At 1715, the UE may determine a resource set for one or more modified random access requests based on the control channel command. 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 as described with reference to Figures 9 to 12 The resource manager described is executed.

[0207] At 1720, the UE may transmit the one or more modified random access requests using the determined resource set. 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 as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0208] At 1725, the UE may receive a random access response from the base station in response to the one or more modified random access requests. 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 as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0209] Fig.18 1 is a flow chart of a method 1800 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 1800 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1800 may be implemented by a UE 115 or a component thereof as described herein. Figures 9 to 12 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0210] At 1805, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. 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 as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0211] At 1810, the UE may receive a control channel command from a base station in response to an initial random access request. 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 as described with reference to Figures 9 to 12The control channel command manager described is executed.

[0212] At 1815, the UE may determine a resource set for one or more modified random access requests based on the control channel command. 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 as described with reference to Figures 9 to 12 The resource manager described is executed.

[0213] At 1820, the UE may identify one or more parameters for the one or more modified random access requests based on a first random access opportunity having the same random access opportunity configuration as the initial random access request. The operations of 1820 may be performed according to the methods described herein. In some examples, aspects of the operations of 1820 may be as described with reference to Figures 9 to 12 The random access parameter manager described is performed.

[0214] At 1825, the UE may select a first preamble sequence for the one or more modified random access requests from a first subset of preamble sequences associated with the first random access opportunity, wherein the first subset of preamble sequences does not overlap with a second subset of preamble sequences available for an initial random access request associated with the first random access opportunity. The operations of 1825 may be performed according to the methods described herein. In some examples, aspects of the operations of 1825 may be performed as described with reference to Figures 9 to 12 The described preamble sequence manager is executed.

[0215] At 1830, the UE may transmit the one or more modified random access requests using the determined resource set. The operations of 1830 may be performed according to the methods described herein. In some examples, aspects of the operations of 1830 may be performed as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0216] At 1835, the UE may receive a random access response from the base station in response to the one or more modified random access requests. The operations of 1835 may be performed according to the methods described herein. In some examples, aspects of the operations of 1835 may be performed as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0217] Fig.19 1 is a flow chart of a method 1900 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 1900 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1900 may be implemented by a UE 115 or a component thereof as described herein. Figures 9 to 12In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0218] At 1905, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. 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 as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0219] At 1910, the UE may receive a control channel command from a base station in response to an initial random access request. 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 as described with reference to Figures 9 to 12 The control channel command manager described is executed.

[0220] At 1915, the UE may identify a resource set for one or more modified random access requests based on a second random access opportunity configuration different from the first random access opportunity configuration of the initial random access request. 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 as described with reference to Figures 9 to 12 The resource manager described is executed.

[0221] At 1920, the UE may transmit the one or more modified random access requests using the determined resource set. 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 as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0222] At 1925, the UE may receive a random access response from the base station in response to the one or more modified random access requests. 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 as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0223] Fig. 20 1 is a flow chart of a method 2000 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 2000 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 2000 may be implemented by a UE 115 or a component thereof as described herein. Figures 9 to 12In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0224] At 2005, the UE may receive in RRC signaling a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests. 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 as described with reference to Figures 9 to 12 The resource manager described is executed.

[0225] At 2010, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. The operations of 2010 may be performed according to the methods described herein. In some examples, various aspects of the operations of 2010 may be performed as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0226] At 2015, the UE may receive a control channel command from the base station in response to the initial random access request. 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 as described with reference to Figures 9 to 12 The control channel command manager described is executed.

[0227] At 2020, the UE may determine a resource set for one or more modified random access requests based on the control channel command and the parameters received in the RRC signaling. 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 as described with reference to Figures 9 to 12 The resource manager described is executed.

[0228] At 2025, the UE may transmit the one or more modified random access requests using the determined resource set. 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 as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0229] At 2030, the UE may receive a random access response from the base station in response to the one or more modified random access requests. The operations of 2030 may be performed according to the methods described herein. In some examples, aspects of the operations of 2030 may be performed as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0230] Fig.211 is a flow chart of a method 2100 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 2100 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 2100 may be implemented by a UE 115 or a component thereof as described herein. Figures 9 to 12 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0231] At 2105, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. The operations of 2105 may be performed according to the methods described herein. In some examples, aspects of the operations of 2105 may be performed as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0232] At 2110, the UE may receive a control channel command from a base station in response to an initial random access request. The operations of 2110 may be performed according to the methods described herein. In some examples, aspects of the operations of 2110 may be performed as described with reference to Figures 9 to 12 The control channel command manager described is executed.

[0233] At 2115, the UE may determine a resource set for one or more modified random access requests based on the control channel command. The operations of 2115 may be performed according to the methods described herein. In some examples, aspects of the operations of 2115 may be performed as described with reference to Figures 9 to 12 The resource manager described is executed.

[0234] At 2120, the UE may determine a second preamble for the one or more modified random access requests as a function of a first random access opportunity associated with the initial random access request, a first preamble of the initial random access request, or any combination thereof. The operations of 2120 may be performed according to the methods described herein. In some examples, aspects of the operations of 2120 may be performed as described with reference to Figures 9 to 12 The described preamble sequence manager is executed.

[0235] At 2125, the UE may transmit the one or more modified random access requests using the determined resource set and the second preamble. The operations of 2125 may be performed according to the methods described herein. In some examples, aspects of the operations of 2125 may be performed as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0236] At 2130, the UE may receive a random access response from the base station in response to the one or more modified random access requests. The operations of 2130 may be performed according to the methods described herein. In some examples, aspects of the operations of 2130 may be performed as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0237] Fig. 22 1 is a flow chart of a method 2200 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 2200 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 2200 may be implemented by a UE 115 or a component thereof as described herein. Figures 9 to 12 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0238] At 2205, the UE may transmit to the base station an initial random access request for establishing a wireless connection with the base station. The operations of 2205 may be performed according to the methods described herein. In some examples, aspects of the operations of 2205 may be performed as described with reference to Figures 9 to 12 The random access request manager described is performed.

[0239] At 2210, the UE may receive a control channel command from a base station in response to an initial random access request, and the operations of 2210 may be performed according to the methods described herein. In some examples, various aspects of the operations of 2210 may be performed as described with reference to Figures 9 to 12 The control channel command manager described is executed.

[0240] At 2215, the UE may identify a set of configured parameters for random access opportunities associated with the one or more modified random access requests. The operations of 2215 may be performed according to the methods described herein. In some examples, aspects of the operations of 2215 may be performed as described with reference to Figures 9 to 12 The resource manager described is executed.

[0241] At 2220, the UE may determine the location of a resource set for one or more configured random access requests based on the configured parameter set and one or more of the timing of the control channel command or the offset indicated by the control channel command. The operations of 2220 may be performed according to the methods described herein. In some examples, aspects of the operations of 2220 may be performed as described with reference to Figures 9 to 12 The resource manager described is executed.

[0242] At 2225, the UE may transmit the one or more modified random access requests using the determined resource set. The operations of 2225 may be performed according to the methods described herein. In some examples, aspects of the operations of 2225 may be performed as described with reference to Figures 9 to 12 The beam refinement manager described herein is used to perform the

[0243] At 2230, the UE may receive a random access response from the base station in response to the one or more modified random access requests. The operations of 2230 may be performed according to the methods described herein. In some examples, aspects of the operations of 2230 may be performed as described with reference to Figures 9 to 12 The random access response manager described is performed.

[0244] Fig.23 2300 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 2300 may be implemented by the base station 105 or components thereof as described herein. For example, the operations of the method 2300 may be implemented by the base station 105 or components thereof as described herein. Figure 13 to Figure 16 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0245] At 2305, the base station may receive an initial random access request from the UE to establish a wireless connection with the base station. The operations of 2305 may be performed according to the methods described herein. In some examples, aspects of the operations of 2305 may be performed as described with reference to Figures 13 to 16 The random access request manager described is performed.

[0246] At 2310, the base station may transmit a control channel command to the UE in response to the initial random access request. The operations of 2310 may be performed according to the methods described herein. In some examples, aspects of the operations of 2310 may be performed as described with reference to Figures 13 to 16 The control channel command manager described is executed.

[0247] At 2315, the base station may determine a resource set for one or more modified random access requests based on the control channel command. The operations of 2315 may be performed according to the methods described herein. In some examples, aspects of the operations of 2315 may be performed as described with reference to Figures 13 to 16 The resource manager described is executed.

[0248] At 2320, the base station may monitor the one or more modified random access requests using the determined resource set. The operations of 2320 may be performed according to the methods described herein. In some examples, aspects of the operations of 2320 may be performed as described with reference to Figures 13 to 16 The resource manager described is executed.

[0249] At 2325, the base station may transmit a random access response to the UE using one or more beamforming parameters based on measurements associated with the one or more modified random access requests. The operations of 2325 may be performed according to the methods described herein. In some examples, aspects of the operations of 2325 may be performed as described with reference to Figures 13 to 16 The random access response manager described is performed.

[0250] Fig.24 2400 for supporting beam refinement techniques for random access communications according to aspects of the present disclosure. The operations of the method 2400 may be implemented by the base station 105 or components thereof as described herein. For example, the operations of the method 2400 may be implemented by the base station 105 or components thereof as described herein. Figures 13 to 16 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0251] At 2405, the base station may transmit in RRC signaling a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests. The operations of 2405 may be performed according to the methods described herein. In some examples, aspects of the operations of 2405 may be performed as described with reference to Figures 13 to 16 The resource manager described is executed.

[0252] At 2410, the base station may receive an initial random access request from a UE to establish a wireless connection with the base station. The operations of 2410 may be performed according to the methods described herein. In some examples, aspects of the operations of 2410 may be performed as described with reference to Figures 13 to 16 The random access request manager described is performed.

[0253] At 2415, the base station may transmit a control channel command to the UE in response to the initial random access request. The operations of 2415 may be performed according to the methods described herein. In some examples, aspects of the operations of 2415 may be performed as described with reference to Figures 13 to 16 The control channel command manager described is executed.

[0254] At 2420, the base station may provide an indication to the UE in a control channel command that identifies the resource set and triggers transmission of the one or more modified random access requests based on the parameter set in a random access opportunity. The operations of 2420 may be performed according to the methods described herein. In some examples, aspects of the operations of 2420 may be as described with reference to Figures 13 to 16The control channel command manager described is executed.

[0255] At 2425, the base station may determine a resource set for one or more modified random access requests based on the control channel command. The operations of 2425 may be performed according to the methods described herein. In some examples, aspects of the operations of 2425 may be performed as described with reference to Figures 13 to 16 The resource manager described is executed.

[0256] At 2430, the base station may monitor the one or more modified random access requests using the determined resource set. The operations of 2430 may be performed according to the methods described herein. In some examples, aspects of the operations of 2430 may be performed as described with reference to Figures 13 to 16 The resource manager described is executed.

[0257] At 2435, the base station may transmit a random access response to the UE using one or more beamforming parameters based on measurements associated with the one or more modified random access requests. The operations of 2435 may be performed according to the methods described herein. In some examples, aspects of the operations of 2435 may be performed as described with reference to Figures 13 to 16 The random access response manager described is performed.

[0258] It should be noted that the methods described herein describe possible implementations, and that the various operations and steps may be rearranged or otherwise modified and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0259] The following provides an overview of various aspects of the disclosure:

[0260] Aspect 1: A method for wireless communication at a UE, comprising: transmitting an initial random access request to a base station to establish a wireless connection with the base station; receiving a control channel command from the base station in response to the initial random access request; transmitting one or more modified random access requests using a resource set based at least in part on the control channel command; and receiving a random access response from the base station in response to the one or more modified random access requests.

[0261] Aspect 2: The method of aspect 1, wherein one or more parameters used for the one or more modified random access requests are based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

[0262] Aspect 3: A method as described in Aspect 2, wherein the resource set is in a subsequent random access opportunity of the first random access opportunity, and the subsequent random access opportunity is determined at least in part based on a control channel command, wherein the subsequent random access opportunity is associated with the same synchronization signal block (SSB) as the first random access opportunity.

[0263] Aspect 4: The method as described in any of Aspects 2 to 3 further includes: selecting a first preamble sequence for the one or more modified random access requests from a first preamble sequence subset associated with a first random access opportunity, wherein the first preamble sequence subset does not overlap with a second preamble sequence subset available for an initial random access request associated with the first random access opportunity.

[0264] Aspect 5: A method as described in Aspect 1, wherein the resource set used for the one or more modified random access requests is at least partially based on a second random access timing configuration that is different from the first random access timing configuration of the initial random access request, and wherein the second random access timing configuration is received in RRC signaling from the base station.

[0265] Aspect 6: The method of aspect 5, wherein the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for an initial random access request.

[0266] Aspect 7: The method of aspect 6, wherein a plurality of different random access opportunities for transmitting the modified random access request are configured for each of a plurality of different SSBs.

[0267] Aspect 8: The method as described in any one of Aspects 5 to 7, wherein the second random access opportunity configuration is not associated with any synchronization signal block (SSB).

[0268] Aspect 9: The method of aspect 1, wherein the determining further comprises: identifying the resource set based at least in part on an indication provided by a control channel command.

[0269] Aspect 10: The method as described in Aspect 9 further includes: receiving a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests in RRC signaling, and wherein a control channel command triggers the transmission of the one or more modified random access requests in the random access opportunity, and wherein the RRC signaling provides one or more of the time resources or frequency resources for the random access opportunity, the number of repetitions of the one or more modified random access requests, or any combination thereof.

[0270] Aspect 11: The method of aspect 10, wherein the control channel command serves as an uplink grant for the one or more modified random access requests using the resource set, and the resource set is determined based at least in part on a location of the control channel command.

[0271] Aspect 12: The method as described in any one of Aspects 1 to 11 further includes: determining a second preamble code for the one or more modified random access requests as a function of a first random access opportunity associated with an initial random access request, a first preamble code of the initial random access request, or any combination thereof, and wherein the function is further based at least in part on a control value provided in a control channel command.

[0272] Aspect 13: The method of aspect 12, wherein the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof.

[0273] Aspect 14: A method as described in any one of Aspects 12 to 13, wherein the same preamble is used for each of two or more repetitions of the modified random access request, or a different preamble is used for each of two or more repetitions of the modified random access request based on a frequency hopping algorithm.

[0274] Aspect 15: The method as described in any one of aspects 1 to 14, wherein the starting random access opportunity index associated with the resource set is determined at least in part based on the time domain position of the control channel command.

[0275] Aspect 16: The method as described in any one of Aspects 1 to 15 further comprises: determining a second random access preamble for the one or more modified random access requests as a function of the first random access preamble for the initial random access request.

[0276] Aspect 17: The method according to any one of aspects 1 to 16, wherein the resource set comprises resources in a second random access opportunity, the second random access opportunity being determined as a function of a first random access opportunity associated with the initial random access request.

[0277] Aspect 18: A method for wireless communication at a base station, comprising: receiving an initial random access request from a UE to establish a wireless connection with the base station; transmitting a control channel command to the UE in response to the initial random access request; determining a resource set for one or more modified random access requests based at least in part on the control channel command; monitoring the one or more modified random access requests using the determined resource set; and transmitting a random access response to the UE using one or more beamforming parameters, the one or more beamforming parameters being based at least in part on measurements associated with the one or more modified random access requests.

[0278] Aspect 19: The method of aspect 18, wherein the determining further comprises: identifying one or more parameters for the one or more modified random access requests based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

[0279] Aspect 20: A method as described in Aspect 19, wherein the determination further includes: identifying the resource set in a subsequent random access opportunity of the first random access opportunity based at least in part on a control channel command, wherein the subsequent random access opportunity is associated with the same synchronization signal block (SSB) as the first random access opportunity.

[0280] Aspect 21: A method as described in any one of Aspects 19 to 20, wherein a first subset of preamble sequences for a first random access opportunity is associated with an initial random access request message, and a second subset of preamble sequences for the first random access opportunity is associated with a modified random access message, wherein the first subset of preamble sequences does not overlap with the second subset of preamble sequences.

[0281] Aspect 22: The method of aspect 18, wherein the determining further comprises: identifying the resource set for the one or more modified random access requests based at least in part on a second random access opportunity configuration different from the first random access opportunity configuration of the initial random access request.

[0282] Aspect 23: A method as described in Aspect 22, wherein the second random access opportunity configuration includes parameters for one or more of the following: a time resource of the second random access opportunity, a frequency resource of the second random access opportunity, a number of repetitions of the one or more modified random access requests to be transmitted, or any combination thereof.

[0283] Aspect 24: The method as described in Aspect 18 further includes: transmitting a parameter set associated with a random access opportunity for transmitting the one or more modified random access requests in RRC signaling, and wherein a control channel command triggers the transmission of the one or more modified random access requests in the random access opportunity.

[0284] Aspect 25: The method as described in any one of Aspects 18 to 24 further includes: determining that the one or more modified random access requests are associated with the UE based on the one or more modified random access requests having a preamble that is a function of the first random access opportunity associated with the initial random access request, the first preamble of the initial random access request, or any combination thereof.

[0285] Aspect 26: An apparatus for wireless communication at a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method as described in any one of Aspects 1 to 17.

[0286] Aspect 27: An apparatus for wireless communication at a UE, comprising at least one means for performing the method as described in any one of aspects 1 to 17.

[0287] Aspect 28: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method as described in any one of aspects 1 to 17.

[0288] Aspect 29: An apparatus for performing wireless communications at a base station, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method as described in any one of Aspects 18 to 25.

[0289] Aspect 30: An apparatus for wireless communication at a base station, comprising at least one device for performing the method as described in any one of Aspects 18 to 25.

[0290] Aspect 31: A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method of any one of aspects 18 to 25.

[0291] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applied to various other wireless communication 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, and other systems and radio technologies not explicitly mentioned herein.

[0292] The information and signals described herein may be represented using any of a variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0293] The various illustrative blocks and components described in conjunction 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. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0294] 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 by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0295] Computer readable medium includes both non-transient computer storage medium and communication medium, and it includes any medium that facilitates computer program to transfer from one place to another place.Non-transient storage medium can be any available medium that can be accessed by general or special-purpose computer.As an example and not limitation, non-transient computer readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used to carry or store instruction or data structure form of desired program code means and can be accessed by general or special-purpose computer or general or special-purpose processor any other non-transient medium.Similarly, any connection is also properly referred to as computer readable medium.For example, if software is transmitted from website, server or other remote source using coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then the coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are just included in the definition of computer readable medium. Disk and disc as used herein include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, 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.

[0296] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so 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). Similarly, as used herein, the phrase "based on" should not be interpreted as referring to a closed set of conditions. For example, an example step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0297] In the accompanying drawings, similar components or features may have the same reference number. In addition, various components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between similar components. If only the first reference number is used in the specification, the description may apply to any of the similar components having the same first reference number regardless of the second reference number, or other subsequent reference numbers.

[0298] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that can be implemented or fall within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0299] The description herein is provided to enable one of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the universal principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment UE, comprising: transmitting an initial random access request to establish a wireless connection with a base station; receiving a control channel command in response to the initial random access request; transmitting one or more modified random access requests using a set of resources based at least in part on the control channel command, the one or more modified random access requests being beam refinement signals; as well as A random access response is received in the refined beam in response to the one or more modified random access requests.

2. The method of claim 1, wherein: One or more parameters for the one or more modified random access requests are based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

3. The method of claim 2, wherein: The resource set is in a subsequent random access opportunity of the first random access opportunity, the subsequent random access opportunity is determined at least in part based on the control channel command, wherein the subsequent random access opportunity is associated with a same synchronization signal block SSB as the first random access opportunity.

4. The method of claim 2, further comprising: A first preamble sequence is selected for the one or more modified random access requests from a first subset of preamble sequences associated with the first random access opportunity, wherein the first subset of preamble sequences does not overlap with a second subset of preamble sequences available for an initial random access request associated with the first random access opportunity.

5. The method of claim 1, wherein: The resource set for the one or more modified random access requests is based at least in part on a second random access opportunity configuration different from a first random access opportunity configuration of the initial random access request, and wherein the second random access opportunity configuration is received in radio resource control (RRC) signaling from the base station.

6. The method of claim 5, wherein the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for the initial random access request.

7. The method of claim 6, wherein a plurality of different random access opportunities for transmitting the modified random access request are configured for each of a plurality of different SSBs.

8. The method of claim 5, wherein the second random access opportunity configuration is not associated with any synchronization signal block (SSB).

9. The method of claim 1, further comprising: The set of resources is identified based at least in part on an indication provided by the control channel command.

10. The method of claim 9, further comprising: A set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests is received in radio resource control (RRC) signaling, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity, and wherein the RRC signaling provides one or more of a time resource or a frequency resource for the random access opportunity, a number of repetitions of the one or more modified random access requests, or any combination thereof.

11. The method of claim 10, wherein the control channel command serves as an uplink grant for the one or more modified random access requests using the resource set, and wherein the resource set is determined based at least in part on a location of the control channel command.

12. The method of claim 1, further comprising: A second preamble for the one or more modified random access requests is determined as a function of a first random access opportunity associated with the initial random access request, a first preamble of the initial random access request, or any combination thereof, and wherein the function is further based at least in part on a control value provided in the control channel command.

13. The method of claim 12, wherein the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof.

14. The method of claim 12, wherein the same preamble is used for each of two or more repetitions of the modified random access request, or a different preamble is used for each of two or more repetitions of the modified random access request based on a frequency hopping algorithm.

15. The method of claim 1, wherein a starting random access opportunity index associated with the resource set is determined based at least in part on a time domain location of the control channel command.

16. The method of claim 1, further comprising: A second random access preamble for the one or more modified random access requests is determined as a function of the first random access preamble for the initial random access request.

17. The method of claim 1, wherein the set of resources comprises resources in a second random access opportunity, the second random access opportunity being determined as a function of a first random access opportunity associated with the initial random access request.

18. A method for wireless communication at a base station, comprising: receiving an initial random access request to establish a wireless connection with the base station; transmitting a control channel command in response to the initial random access request; determining a set of resources for one or more modified random access requests based at least in part on the control channel command; monitoring the one or more modified random access requests using the determined set of resources, the one or more modified random access requests being beam refinement signals; as well as A random access response is transmitted in the refined beam using one or more beamforming parameters based at least in part on measurements associated with the one or more modified random access requests.

19. The method of claim 18, wherein the determining further comprises: One or more parameters for the one or more modified random access requests are identified based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

20. The method of claim 19, wherein the determining further comprises: The resource set in a subsequent random access opportunity of the first random access opportunity is identified based at least in part on the control channel command, wherein the subsequent random access opportunity is associated with a same synchronization signal block (SSB) as the first random access opportunity.

21. The method of claim 19, wherein the first subset of preamble sequences for the first random access opportunity is associated with an initial random access request message, and the second subset of preamble sequences for the first random access opportunity is associated with a modified random access message, wherein the first subset of preamble sequences does not overlap with the second subset of preamble sequences.

22. The method of claim 18, wherein the determining further comprises: The resource set for the one or more modified random access requests is identified based at least in part on a second random access opportunity configuration different from a first random access opportunity configuration of the initial random access request.

23. The method of claim 22, wherein the second random access opportunity configuration comprises parameters for one or more of: a time resource of the second random access opportunity, a frequency resource of the second random access opportunity, a number of repetitions of the one or more modified random access requests to be transmitted, or any combination thereof.

24. The method of claim 18, further comprising: A set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests is transmitted in radio resource control (RRC) signaling, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity.

25. The method of claim 18, further comprising: Determining that the one or more modified random access requests are associated with a user equipment UE is based on the one or more modified random access requests having a preamble that is a function of a first random access opportunity associated with the initial random access request, a first preamble of the initial random access request, or any combination thereof.

26. An apparatus for wireless communication at a user equipment UE, comprising: means for transmitting an initial random access request to establish a wireless connection with a base station; means for receiving a control channel command in response to the initial random access request; means for transmitting one or more modified random access requests using a set of resources based at least in part on the control channel command, the one or more modified random access requests being beam refinement signals; as well as Means for receiving a random access response in the refined beam in response to the one or more modified random access requests.

27. The apparatus of claim 26, wherein: One or more parameters for the one or more modified random access requests are based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

28. The apparatus of claim 27, wherein: The resource set is in a subsequent random access opportunity of the first random access opportunity, the subsequent random access opportunity is determined at least in part based on the control channel command, wherein the subsequent random access opportunity is associated with a same synchronization signal block SSB as the first random access opportunity.

29. The apparatus of claim 27, further comprising: Means for selecting a first preamble sequence for the one or more modified random access requests from a first subset of preamble sequences associated with the first random access opportunity, wherein the first subset of preamble sequences does not overlap with a second subset of preamble sequences available for an initial random access request associated with the first random access opportunity.

30. The apparatus of claim 26, wherein: The resource set for the one or more modified random access requests is based at least in part on a second random access opportunity configuration different from a first random access opportunity configuration of the initial random access request, and wherein the second random access opportunity configuration is received in radio resource control (RRC) signaling from the base station.

31. The apparatus of claim 30, wherein the second random access opportunity configuration is associated with a synchronization signal block (SSB) used to identify uplink resources for the initial random access request.

32. The apparatus of claim 31, wherein a plurality of different random access opportunities for transmitting the modified random access request are configured for each of a plurality of different SSBs.

33. The apparatus of claim 30, wherein the second random access opportunity configuration is not associated with any synchronization signal block (SSB).

34. The apparatus of claim 26, further comprising: means for identifying the set of resources based at least in part on an indication provided by the control channel command.

35. The apparatus of claim 34, further comprising: Means for receiving, in radio resource control (RRC) signaling, a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity, and wherein the RRC signaling provides one or more of a time resource or a frequency resource for the random access opportunity, a number of repetitions of the one or more modified random access requests, or any combination thereof.

36. The apparatus of claim 35, wherein the control channel command serves as an uplink grant for the one or more modified random access requests using the resource set, and wherein the resource set is determined based at least in part on a location of the control channel command.

37. The apparatus of claim 26, further comprising: Means for determining a second preamble for the one or more modified random access requests as a function of a first random access opportunity associated with the initial random access request, a first preamble of the initial random access request, or any combination thereof, and wherein the function is further based at least in part on a control value provided in the control channel command.

38. The apparatus of claim 37, wherein the function outputs one or more of a frequency domain index for the one or more modified random access requests, a preamble index for the one or more modified random access requests, or any combination thereof.

39. The apparatus of claim 37, wherein the same preamble is used for each of two or more repetitions of the modified random access request, or a different preamble is used for each of two or more repetitions of the modified random access request based on a frequency hopping algorithm.

40. The apparatus of claim 26, wherein a starting random access opportunity index associated with the resource set is determined based at least in part on a time domain location of the control channel command.

41. The apparatus of claim 26, further comprising: Means for determining a second random access preamble for the one or more modified random access requests as a function of the first random access preamble for the initial random access request.

42. The apparatus of claim 26, wherein the set of resources comprises resources in a second random access opportunity, the second random access opportunity being determined as a function of a first random access opportunity associated with the initial random access request.

43. An apparatus for wireless communication at a base station, comprising: means for receiving an initial random access request to establish a wireless connection with the base station; means for transmitting a control channel command in response to said initial random access request; means for determining a set of resources for one or more modified random access requests based at least in part on the control channel command; means for monitoring the one or more modified random access requests using the determined set of resources, the one or more modified random access requests being beam refinement signals; as well as Means for transmitting a random access response in a refined beam using one or more beamforming parameters based at least in part on measurements associated with the one or more modified random access requests.

44. The apparatus of claim 43, further comprising: Means for identifying one or more parameters for the one or more modified random access requests based at least in part on a first random access opportunity having the same random access opportunity configuration as the initial random access request.

45. The apparatus of claim 44, wherein the determining further comprises: The resource set in a subsequent random access opportunity of the first random access opportunity is identified based at least in part on the control channel command, wherein the subsequent random access opportunity is associated with a same synchronization signal block (SSB) as the first random access opportunity.

46. ​​The apparatus of claim 44, wherein a first subset of preamble sequences for the first random access opportunity is associated with an initial random access request message, and a second subset of preamble sequences for the first random access opportunity is associated with a modified random access message, wherein the first subset of preamble sequences does not overlap with the second subset of preamble sequences.

47. The apparatus of claim 43, wherein the determining further comprises: The resource set for the one or more modified random access requests is identified based at least in part on a second random access opportunity configuration different from a first random access opportunity configuration of the initial random access request.

48. The apparatus of claim 47, wherein the second random access opportunity configuration comprises parameters for one or more of: a time resource of the second random access opportunity, a frequency resource of the second random access opportunity, a number of repetitions of the one or more modified random access requests to be transmitted, or any combination thereof.

49. The apparatus of claim 43, further comprising: means for transmitting, in radio resource control (RRC) signaling, a set of parameters associated with a random access opportunity for transmitting the one or more modified random access requests, and wherein the control channel command triggers transmission of the one or more modified random access requests in the random access opportunity.

50. The apparatus of claim 43, further comprising: Means for determining that the one or more modified random access requests are associated with a user equipment UE based on the one or more modified random access requests having a preamble that is a function of a first random access opportunity associated with the initial random access request, a first preamble of the initial random access request, or any combination thereof.

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