Beam association in random access procedures

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may determine a mapping between a synchronization signal block (SSB) and a random access message of a two-step random access procedure based on an indication in system information signaling or radio resource control (RRC) signaling. The random access message may include a random access preamble and a random access payload. The UE may determine an association between one or more beams carrying the SSB and one or more additional beams carrying a random access preamble and a random access payload of the random access message based on the mapping. Accordingly, the UE may perform a two-step random access procedure with the base station according to beam association and coexist with a four-step random access procedure in a more reliable and efficient manner.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of June 1, 2020, application number 202080037657.9, and invention name “Beam association in random access process”.

[0002] Cross-references

[0003] This patent application claims the benefits of: U.S. Provisional Patent Application No. 62 / 856,683, filed by LEI et al. on June 3, 2019, entitled “BEAM ASSOCIATION IN RANDOMACCESS PROCEDURES”; and U.S. Patent Application No. 16 / 887,970, filed by LEI et al. on May 29, 2020, entitled “BEAM ASSOCIATION IN RANDOMACCESS PROCEDURES”, each of which is assigned to the assignee of this application. Technical Field

[0004] The following generally relates to wireless communications, and more particularly, the following relates to beam association in a random access procedure. Background Art

[0005] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, etc. These systems can 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 (e.g., long term evolution (LTE) systems, improved 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 employ techniques 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 spread spectrum orthogonal frequency division multiplexing (DFT-S-OFDM).

[0006] A wireless multiple access communication system may include multiple base stations or network access nodes, each of which simultaneously supports communication for multiple communication devices (which may be otherwise referred to as user equipment (UE)). Some wireless communication systems may support one or more random access procedures. The random access procedure may involve a series of handshake messages exchanged between the UE and the base station. As the demand for efficiency of wireless communication systems increases, some wireless communication systems may fail to provide robustness for beam association and enhanced random access messaging, and therefore improved techniques are desired. Summary of the invention

[0007] The described techniques relate to improved methods, systems, devices and apparatuses for supporting beam association in a random access procedure. In summary, the described techniques provide for a user equipment (UE) to determine a mapping between a synchronization signal block (SSB) and a random access message, for example, involving a two-step random access procedure. The UE may also determine an association between one or more corresponding directional beams carrying the SSB and one or more additional corresponding directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message).

[0008] Additionally, in some examples, the described techniques may include mapping the time and frequency resources of the SSB to one or more PRACH opportunities (ROs) of a random access preamble and one or more physical uplink shared channel (PUSCH) resource units (PRUs) of a random access payload within a physical random access channel (PRACH) configuration period in an association mode period of a two-step random access procedure. Additionally or alternatively, the described techniques may include beam association for a random access fallback procedure and a random access switching procedure. Thus, the described techniques may include features for improved resource usage and allocation for random access message transmission, improved reliability for random access message transmission, and in some examples, may facilitate low latency for a random access procedure, among other benefits.

[0009] A method of wireless communication at a user equipment is described. The method may include: determining, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determining, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with a base station.

[0010] An apparatus for wireless communication at a user equipment 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 perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; determine an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and perform the two-step random access procedure with a base station.

[0011] Another apparatus for wireless communication at a user equipment is described. The apparatus may include means for: determining, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determining, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with a base station.

[0012] A non-transitory computer-readable medium storing code for wireless communication at a user equipment is described. The code may include instructions executable by a processor to: determine, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determine, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access procedure with a base station.

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for mapping resources of the synchronization signal block to one or more physical random access channel opportunities of the random access preamble and one or more physical uplink shared channel resource units of the random access payload within a physical random access channel configuration period in an association mode period of the two-step random access procedure.

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining the association mode period of the two-step random access procedure based on a second indication, wherein the association mode period of the two-step random access procedure may be a factor value based on the association mode period of the four-step random access procedure, and the factor value includes an integer value within a range configured by the network.

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining a second association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble code and the random access payload of the random access message within an additional physical random access channel configuration period in a second association mode period of the two-step random access procedure, and wherein the second association within the second association mode period of the two-step random access procedure may be different from the association within the association mode period of the two-step random access procedure.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: receiving signaling including the indication from the base station, the indication including the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble code and the random access payload of the random access message, wherein the signaling includes system information signaling or radio resource control signaling or both.

[0017] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble code and the random access payload of the random access message based on a physical random access channel opportunity index of the one or more physical random access channel opportunities, wherein the indication includes the physical random access channel opportunity index.

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining, based on a preamble sequence of the random access preamble, the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message, wherein the indication includes the preamble sequence.

[0019] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble code and the random access payload of the random access message based on a physical uplink shared channel resource unit index associated with the one or more physical uplink shared channel resource units of the random access payload, wherein the indication includes the physical uplink shared channel resource unit index.

[0020] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message based on multiplexing uplink control information onto one or more of the random access preamble and the random access payload of the random access message, wherein the indication includes the multiplexing of the uplink control information.

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble and the random access payload of the random access message may be associated with different ones of the synchronization signal blocks based on a guard period associated with the random access preamble and a duration of a gap period between the random access preamble and the random access payload.

[0022] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining that one or more physical uplink shared channel resource units of the random access payload share one or more of the time resources and the frequency resources; and determining a mapping between the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources and a synchronization signal block in the synchronization signal block or a portion of the synchronization signal blocks in the synchronization signal block, wherein the portion of the synchronization signal blocks in the synchronization signal block can be grouped.

[0023] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources and the one synchronization signal block in the synchronization signal block or the portion of the synchronization signal blocks in the synchronization signal block may include operations, features, units, or instructions for performing the following operations: mapping the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources to the one synchronization signal block in the synchronization signal block based on analog beamforming capabilities.

[0024] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources and the one synchronization signal block in the synchronization signal block or the portion of the synchronization signal blocks in the synchronization signal block may include operations, features, units, or instructions for performing the following operations: mapping the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources to the portion of the synchronization signal blocks in the synchronization signal block based on digital beamforming capabilities.

[0025] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining that the one or more physical random access channel opportunities of the random access preamble code can be shared with one or more additional random access preamble codes of the four-step random access process based on UE capabilities, random access process fallback capabilities, load balancing capabilities, or multiplexing of contention-free random access and contention-based random access, or any combination thereof.

[0026] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining that the number of synchronization signal blocks satisfies a threshold; and determining that the random access preamble code of the random access message of the two-step random access process and the random access message of the four-step random access process can be configured to have different preamble code sequence subsets.

[0027] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indexes of the preamble sequences in each of the subsets of preamble sequences may be consecutive.

[0028] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: the preamble sequences in each of the preamble sequence subsets may be non-overlapping.

[0029] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure may have the same receive beam.

[0030] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining that the number of synchronization signal blocks can be greater than a threshold, wherein the number of synchronization signal blocks can be mapped to the same physical random access channel opportunity among the one or more physical random access channel opportunities shared between the random access preamble code of the two-step random access process and the random access message of the four-step random access process.

[0031] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the number of synchronization signal blocks can have different transmit beams.

[0032] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure may be mapped to different synchronization signal blocks among the number of synchronization signal blocks.

[0033] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a portion of the random access preamble code in the number of synchronization signal blocks that is mapped to the two-step random access process can be one or more of the following: continuous in the time domain, or discontinuous in the time domain.

[0034] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: based on the spatial separation of the transmit beams of the random access preamble mapped to the two-step random access process and the random access message of the four-step random access process, the transmit beams of the random access preamble mapped to the two-step random access process and the random access message of the four-step random access process may have the same or different preamble sequence sizes.

[0035] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure may have different receive beams.

[0036] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, executing the two-step random access process may include operations, features, units, or instructions for performing the following operations: sending the random access message of the two-step random access process to the base station during an association mode period; and retransmitting the random access message of the two-step random access process during the association mode period based on a retransmission counter being less than a threshold.

[0037] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing beam switching of the one or more additional beams carrying the random access preamble or the random access payload or both of the random access message.

[0038] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining a change in a physical random access channel opportunity index of the one or more physical random access channel opportunities, and wherein performing the beam switching of the one or more additional beams carrying the random access preamble code or the random access payload or both of the random access message can be based on the change in the physical random access channel opportunity index.

[0039] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining a change in a physical uplink shared channel resource unit index associated with the one or more physical uplink shared channel resource units of the random access payload, and wherein performing the beam switching of the one or more additional beams carrying the random access preamble code or the random access payload or both of the random access message can be based on the change in the physical uplink shared channel resource unit index associated with the one or more physical uplink shared channel resource units of the random access payload.

[0040] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining a change in a preamble sequence index of the random access preamble, and wherein performing the beam switching of the one or more additional beams carrying the random access preamble or the random access payload or both of the random access message may be based on the change in the random access preamble.

[0041] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining to multiplex uplink control information onto one or more of the random access preamble and the random access payload of the random access message, and wherein performing the beam switching of the one or more additional beams carrying the random access preamble or the random access payload or both of the random access message may be based on multiplexing the uplink control information onto one or more of the random access preamble and the random access payload of the random access message.

[0042] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: in conjunction with additional beam switching of the one or more beams carrying the synchronization signal block by the base station, performing the beam switching of the one or more additional beams carrying the random access preamble code or the random access payload or both of the random access message.

[0043] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the beam switching can be enabled based on one or more of the association, the mapping, or a trigger indication, the trigger indication comprising one or more of a preamble sequence, a reference signal, or uplink control information.

[0044] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: executing a random access fallback process or a random access switching process from the two-step random access process to the four-step random access process, wherein performing the beam switching may be based on the random access fallback process or the random access switching process.

[0045] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: identifying a random access message of the four-step random access process based on the random access fallback process or the random access switching process, wherein performing the beam switching may be based on control signaling including downlink control information from the base station, and the beam switching includes switching one or more of a transmit beam and a receive beam.

[0046] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: identifying a random access message of the four-step random access process based on the random access fallback process or the random access switching process, wherein performing the beam switching may be based on pre-configuration information including the association.

[0047] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for the following items: based on the retransmission counter satisfying the threshold, the resources for sending the random access message of the two-step random access procedure to the base station during the association mode period may be the same resources for retransmitting the random access message of the two-step random access procedure during the association mode period.

[0048] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for the following items: based on the retransmission counter satisfying the threshold, resources for sending the random access message of the two-step random access procedure to the base station during an association mode period may be different from resources for retransmitting the random access message of the two-step random access procedure during the association mode period.

[0049] A method of wireless communication at a base station is described. The method may include: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; sending information including one or more of the following to a user equipment: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0050] 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 perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information including one or more of the following items to a user equipment: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access procedure with the user equipment according to the mapping.

[0051] Another apparatus for wireless communication at a base station is described. The apparatus may include a unit for performing the following operations: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; sending information including one or more of the following items to a user equipment: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0052] 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 perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information to a user equipment including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access procedure with the user equipment according to the mapping.

[0053] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for mapping resources of the synchronization signal block to one or more physical random access channel opportunities of the random access preamble and one or more physical uplink shared channel resource units of the random access payload within a physical random access channel configuration period in an association mode period of the two-step random access procedure.

[0054] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending the information to the user equipment may include operations, features, units, or instructions for performing the following operations: sending signaling including the information, the information including one or more of the following items: the mapping between the synchronization signal block and the random access message of the two-step random access process, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble code and the random access payload of the random access message, wherein the signaling includes system information signaling or radio resource control signaling or both.

[0055] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble and the random access payload of the random access message may be associated with different ones of the synchronization signal blocks based on a guard period associated with the random access preamble and a duration of a gap period between the random access preamble and the random access payload.

[0056] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining that one or more physical uplink shared channel resource units of the random access payload share one or more of the time resources and the frequency resources; and determining a mapping between the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources and a synchronization signal block in the synchronization signal block or a portion of the synchronization signal blocks in the synchronization signal block, wherein the portion of the synchronization signal blocks in the synchronization signal block can be grouped.

[0057] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources and the one synchronization signal block in the synchronization signal block or the portion of the synchronization signal blocks in the synchronization signal block may include operations, features, units, or instructions for performing the following operations: mapping the one or more physical uplink shared channel resource units of the random access payload that share one or more of the time resources and the frequency resources to the one synchronization signal block in the synchronization signal block based on analog beamforming capabilities.

[0058] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between the one or more physical uplink shared channel resource units that share the time resources of the random access payload and the one or more synchronization signal blocks in the synchronization signal block or the portion of the synchronization signal blocks in the synchronization signal block may include operations, features, units, or instructions for performing the following operations: mapping the one or more physical uplink shared channel resource units that share the time resources of the random access payload to the portion of the synchronization signal blocks in the synchronization signal block based on digital beamforming capabilities.

[0059] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining that the number of synchronization signal blocks satisfies a threshold; and determining that the random access preamble code of the random access message of the two-step random access process and the random access message of the four-step random access process can have the same receiving beam and can be configured to have different preamble code sequence subsets.

[0060] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: determining that the number of synchronization signal blocks can be greater than a threshold, wherein the number of synchronization signal blocks can be mapped to the same physical random access channel opportunity in one or more physical random access channel opportunities shared between the random access preamble code of the two-step random access process and the random access message of the four-step random access process.

[0061] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the number of synchronization signal blocks can have different transmit beams.

[0062] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure may be mapped to different synchronization signal blocks among the number of synchronization signal blocks.

[0063] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a portion of the random access preamble code in the number of synchronization signal blocks that is mapped to the two-step random access process can be one or more of the following: continuous in the time domain, or discontinuous in the time domain.

[0064] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure may have different receive beams.

[0065] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing beam switching of the one or more additional beams carrying the random access preamble or the random access payload or both of the random access message, wherein the one or more additional beams include a receive beam.

[0066] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: in conjunction with the beam switching of the one or more beams carrying the synchronization signal block, performing beam switching of the one or more additional beams carrying the random access preamble code or the random access payload or both of the random access message, wherein the one or more additional beams include receive beams and the one or more beams carrying the synchronization signal block include transmit beams.

[0067] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: executing a random access fallback process or a random access switching process from the two-step random access process to the four-step random access process, wherein performing the beam switching may be based on the random access fallback process or the random access switching process.

[0068] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: identifying a random access message of the four-step random access process based on the random access fallback process or the random access switching process; and sending control signaling including downlink control information to the user equipment, wherein performing the beam switching may be based on the control signaling, and the beam switching includes switching one or more of a transmit beam and a receive beam.

[0069] A method of wireless communication is described. The method may include determining, based on a mapping, an association between one or more beams carrying a synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of a random access message; and performing a two-step random access procedure with a base station.

[0070] An apparatus for wireless communication 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 perform the following operations: determine an association between one or more beams carrying a synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of a random access message based on a mapping; and perform a two-step random access procedure with a base station.

[0071] Another apparatus for wireless communication is described. The apparatus may include means for determining, based on a mapping, an association between one or more beams carrying a synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of a random access message; and performing a two-step random access procedure with a base station.

[0072] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: determine, based on a mapping, an association between one or more beams carrying a synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of a random access message; and perform a two-step random access procedure with a base station.

[0073] A method of wireless communication is described. The method may include: sending information to a user equipment, the information including one or more of: a mapping between a synchronization signal block and a random access message of a two-step random access procedure, and an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0074] An apparatus for wireless communication 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 perform the following operations: send information to a user equipment, the information including one or more of the following: a mapping between a synchronization signal block and a random access message of a two-step random access procedure, and an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and perform the two-step random access procedure with the user equipment according to the mapping.

[0075] Another apparatus for wireless communication is described. The apparatus may include means for performing the following operations: sending information to a user equipment, the information including one or more of the following: a mapping between a synchronization signal block and a random access message of a two-step random access procedure, and an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0076] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: send information to a user equipment, the information including one or more of: a mapping between a synchronization signal block and a random access message of a two-step random access procedure, and an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and perform the two-step random access procedure with the user equipment according to the mapping.

[0077] A method of wireless communication is described. The method may include: means for determining, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; means for determining, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and means for performing the two-step random access procedure with a base station.

[0078] An apparatus for wireless communication 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 perform the following operations: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; a unit for determining an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and a unit for performing the two-step random access procedure with a base station.

[0079] Another apparatus for wireless communication is described. The apparatus may include: means for determining, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; means for determining, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and means for performing the two-step random access procedure with a base station.

[0080] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to perform the following operations: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; a unit for determining an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and a unit for performing the two-step random access procedure with a base station.

[0081] A method for wireless communication is described. The method may include: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; a unit for sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and a unit for performing the two-step random access procedure with the user equipment according to the mapping.

[0082] An apparatus for wireless communication 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 perform the following operations: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; a unit for sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and a unit for performing the two-step random access procedure with the user equipment according to the mapping.

[0083] Another apparatus for wireless communication is described. The apparatus may include: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; a unit for sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and a unit for performing the two-step random access procedure with the user equipment according to the mapping.

[0084] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to perform the following operations: a unit for determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; a unit for sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and a unit for performing the two-step random access procedure with the user equipment according to the mapping.

[0085] A method of wireless communication at a user equipment is described, the code including instructions executable by a processor. The method may include: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; determining an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and performing the two-step random access procedure with a base station.

[0086] An apparatus for wireless communication at a user equipment is described, the code including instructions executable by a processor. 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 perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; determine an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and perform the two-step random access procedure with a base station.

[0087] Another apparatus for wireless communication at a user equipment is described, the code including instructions executable by a processor. The apparatus may include means for performing the following operations: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure based on an indication, the random access message including a random access preamble and a random access payload; determining an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on the mapping; and performing the two-step random access procedure with a base station.

[0088] A non-transitory computer-readable medium storing code for wireless communication at a user equipment is described, the code including instructions executable by a processor. The code may include instructions executable by the processor to: determine, based on an indication, a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determine, based on the mapping, an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access procedure with a base station.

[0089] A method of wireless communication at a base station is described, the code including instructions executable by a processor. The method may include: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0090] A device for wireless communication at a base station is described, and the code includes instructions that can be executed by a processor. The device 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 device to perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access process, the random access message including a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access process, and the association between the one or more beams carrying the synchronization signal block and the random access preamble and the random access payload of the random access message; and perform the two-step random access process with the user equipment according to the mapping.

[0091] Another apparatus for wireless communication at a base station is described, the code including instructions executable by a processor. The apparatus may include a unit for performing the following operations: determining a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; sending information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and performing the two-step random access procedure with the user equipment according to the mapping.

[0092] A non-transitory computer-readable medium storing code for wireless communication at a base station is described, the code including instructions executable by a processor. The code may include instructions executable by the processor to perform the following operations: determine a mapping between a synchronization signal block and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the synchronization signal block and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information to a user equipment, the information including one or more of the following: the mapping between the synchronization signal block and the random access message of the two-step random access procedure, and the association between the one or more beams carrying the synchronization signal block and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access procedure with the user equipment according to the mapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 An example of a system for wireless communication supporting beam association in a random access procedure in accordance with aspects of the present disclosure is shown.

[0094] Figure 2 An example of a wireless communication system supporting a four-step random access procedure in accordance with aspects of the present disclosure is shown.

[0095] Figure 3 An example of a mapping configuration supporting mapping between one or more physical random access channel (PRACH) configuration periods and an associated mode period in accordance with aspects of the present disclosure is shown.

[0096] Figure 4 An example of a wireless communication system supporting a two-step random access procedure in accordance with aspects of the present disclosure is shown.

[0097] Figure 5 An example of a transmit chain supporting a two-step random access procedure in accordance with various aspects of the present disclosure is shown.

[0098] Fig. 6A An example of a channel structure supporting beam association in a random access procedure according to aspects of the present disclosure is shown.

[0099] Figure 6B An example of a mapping configuration between beam associations in supporting a random access procedure according to aspects of the present disclosure is shown.

[0100] Fig. 7AAn example of a mapping configuration supporting beam association in a random access procedure according to aspects of the present disclosure is shown.

[0101] Figure 7B An example of a mapping configuration between beam associations in supporting a random access procedure according to aspects of the present disclosure is shown.

[0102] Figure 8 An example of a process flow supporting beam association in a random access procedure in accordance with aspects of the present disclosure is shown.

[0103] Fig. 9 and 10 A block diagram of an apparatus supporting beam association in a random access procedure according to aspects of the present disclosure is shown.

[0104] Fig.11 A block diagram of a UE communication manager supporting beam association in a random access procedure in accordance with aspects of the present disclosure is shown.

[0105] Fig.12 A diagram of a system including a device supporting beam association in a random access procedure is shown in accordance with aspects of the present disclosure.

[0106] Fig.13 and 14 A block diagram of an apparatus supporting beam association in a random access procedure according to aspects of the present disclosure is shown.

[0107] Fig.15 A block diagram of a base station communication manager supporting beam association in a random access procedure is shown in accordance with aspects of the present disclosure.

[0108] Fig.16 A diagram of a system including a device supporting beam association in a random access procedure is shown in accordance with aspects of the present disclosure.

[0109] Figures 17 to 20 A flow chart illustrating a method of supporting beam association in a random access procedure according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0110] Some wireless communication systems may enable a user equipment (UE) and a base station (e.g., an eNodeB (eNB), a next generation NodeB, or a Gigabit NodeB (either of which may be referred to as a gNB)) to establish a connection using a random access procedure. The random access procedure may include a series of handshake messages that carry information that facilitates establishing a connection between the UE and the base station. In some examples, the random access procedure may be a two-step random access procedure, wherein the two-step random access procedure may reduce latency compared to other random access procedures that use a larger number of handshake messages (such as a four-step random access procedure). In addition, when the two-step random access procedure is unsuccessful or due to some other condition (e.g., priority, traffic load), the UE may fall back from the two-step random access procedure to the four-step random access procedure. Because the base station and the UE may support multiple random access procedures (e.g., two-step and four-step random access procedures) and multi-beam implementations, the base station may configure the transmission of random access messages so that the UE has the ability to distinguish between random access messages of different types of random access procedures (e.g., two-step and four-step random access procedures) and enable beam association, as described herein.

[0111] The UE may be configured to determine a mapping between a synchronization signal block (SSB) and, for example, a random access message involving a two-step random access procedure. The UE may also determine an association between one or more corresponding directional beams carrying the SSB and one or more additional corresponding directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message). Additionally, in some examples, the described techniques may include mapping the time and frequency resources of the SSB to one or more PRACH opportunities (ROs) of the random access preamble and one or more physical uplink shared channel (PUSCH) resource units (PRUs) of the random access payload within a physical random access channel (PRACH) configuration period of an association mode period of the two-step random access procedure. Additionally or alternatively, the described techniques may include beam association for a random access fallback procedure and a random access switching procedure.

[0112] Certain aspects of the subject matter described herein may be implemented to achieve one or more advantages. The described techniques may support improvements in power saving and other advantages. Therefore, the supported techniques may include improved UE operation, and in some examples, may improve UE efficiency and other benefits. Various aspects of the present disclosure are first described in the context of a wireless communication system. Then, various aspects of the present disclosure are illustrated and described with reference to the above items by mapping configurations, transmission chains, channel structures, and process flows involving beam associations in a random access process. Various aspects of the present disclosure are further illustrated and described with reference to apparatus diagrams, system diagrams, and flow charts involving beam associations in a random access process.

[0113] Figure 1 An example of a wireless communication system 100 supporting beam association in a random access procedure according to aspects of the present disclosure is shown. The wireless communication system 100 may include a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an improved LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, or communications with low-cost and low-complexity devices, or any combination thereof.

[0114] Base stations 105 may be dispersed throughout a geographic area to form a wireless communication system 100, and may be devices of different forms or with different capabilities. Base stations 105 and UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which UEs 115 and base stations 105 may establish communication links 125. Coverage areas 110 may be examples of geographic areas over which base stations 105 and UEs 115 support transmission of signals according to one or more radio access technologies.

[0115] UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein can communicate with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices), such as Figure 1 shown.

[0116] The base stations 105 may communicate with the core network 130, or communicate with each other, or perform both operations. For example, the base station 105 may interface with the core network 130 via a backhaul link 132 (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) on the backhaul link 120 (e.g., via X2, Xn or other interfaces), or communicate with each other indirectly (e.g., via the core network 130), or perform both operations. In some examples, the backhaul link 120 may be or may include one or more wireless links. One or more of the base stations 105 described herein may include or may be referred to by a person of ordinary skill in the art as a base transceiver, a radio base station, an access point, a radio transceiver, a node B, an evolved node B (eNB), a next generation node B or a gigabit node B (either of which may be referred to as a gNB), a home node B, a home evolved node B, or other appropriate terms.

[0117] 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 appropriate terminology, where "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. 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, a machine type communication (MTC) device, and the like, which may be implemented in various objects such as appliances, vehicles, meters, and the like. The UE 115 described herein is capable of communicating with various types of devices, such as other UEs 115 that may sometimes act as repeaters, as well as base stations 105 and network devices (including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, and the like), such as Figure 1 as shown in .

[0118] 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 a physical layer channel of 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 the operation of the carrier, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers.

[0119] 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 placed according to a channel grid to be discovered by a UE 115. A carrier may operate in a standalone mode in which a UE 115 performs initial acquisition and connection 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., of the same or different radio access technology).

[0120] 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 FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode). A carrier may be associated with a specific 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 a plurality of predetermined bandwidths of a carrier for a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). A device in the wireless communication system 100 (e.g., a base station 105, a UE 115, or both) may have a hardware configuration that supports communications on a specific 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 communication 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.

[0121] The signal waveform transmitted on the carrier may be composed of multiple subcarriers (e.g., using multicarrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may be composed of a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol 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 coding rate of the modulation scheme, or both). Therefore, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate for 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 may further increase the data rate or data integrity for communication with UE 115.

[0122] One or more numerologies for a carrier may be supported, where the numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into BWPs with the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some cases, a single BWP for a carrier is active at a given time, and communications for a UE 115 may be limited to the active BWP. The basic time unit (which may be, for example, referred to as T) may be used to determine the BWP. s =1 / (Δf max ·N f ) seconds sampling period, where Δf max It can represent the maximum supported subcarrier spacing, and N f The time intervals for the base station 105 or the UE 115 may be expressed as multiples of a maximum supported discrete Fourier transform (DFT) size). The time intervals of the 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).

[0123] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some cases, a frame may be divided into subframes, and each subframe may be further divided into multiple 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 multiple symbol periods (for example, depending on the length of the cyclic prefix added in front of each symbol period). In some wireless communication systems 100, the time slot may be further divided into multiple mini-time slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (for example, N f The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0124] A subframe, a time slot, a mini-time slot, or a symbol may be the smallest scheduling unit of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some cases, the TTI duration (i.e., 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 a burst of a shortened TTI (sTTI)).

[0125] Physical channels may be multiplexed on a carrier according to various techniques. For example, a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique may be used to multiplex physical control channels and physical data channels on a downlink carrier. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a plurality of symbol periods and may extend over 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 group of UEs 115. For example, a UE 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 with one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with a coding information for a control information format having a given payload size. A search space set may include a common search space set configured for sending control information to a plurality of UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0126] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hot spots or other types of cells, or various combinations thereof). The term "cell" can refer to a logical communication entity used to communicate with the base station 105 (e.g., on a carrier), and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID) or other identifier) ​​used to distinguish adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors (such as the capabilities of the base station 105), the range of such a cell can range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell can be or can include a building, a subset of a building, or an external space between or overlapping geographic coverage areas 110, etc.

[0127] A macro cell typically covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by a UE 115 with a service subscription to a network provider that supports the macro cell. Small cells may be associated with a lower power base station 105 than a macro cell, and small cells may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. Small cells may provide unrestricted access to UEs 115 with a service subscription to a network provider, or may provide restricted access to UEs 115 associated with small cells (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a residence or office, etc.). A base station 105 may support one or more cells, and may also support the use of one or more component carriers to communicate on one or more cells. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or other protocol types) that may provide access to different types of devices.

[0128] In some examples, base stations 105 may be mobile and, therefore, 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 respective geographic coverage areas 110 using the same or different radio access technologies.

[0129] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0130] Some UEs 115 (e.g., MTC or IoT devices) may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application that utilizes the information or presents the information to a human interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, climate and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0131] Some UEs 115 may be configured to employ an operating mode that reduces power consumption, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception rather than simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for UE 115 include entering a power-saving deep sleep mode when not participating in active communications, when operating on a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs 115 may be configured to operate using a narrowband protocol type that is associated with a predetermined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of a carrier, or outside a carrier.

[0132] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. UE115 can be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication, and can 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 can include prioritization of services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably in this article.

[0133] In some cases, UE 115 can also communicate directly with other UE 115 on 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 otherwise unable to receive transmissions from the base station 105. In some cases, multiple groups of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, wherein 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 UEs 115 without involving the base station 105.

[0134] In some systems, the D2D communication link 135 can be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, the vehicle can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these items. The vehicle can use signals to send information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some cases, the vehicle in the V2X system can communicate with roadside infrastructure (such as a roadside unit), or communicate with the network using vehicle-to-network (V2N) communication via one or more network nodes (e.g., base station 105), or communicate with both.

[0135] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connection, and other access, routing or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function unit (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), a user plane function unit (UPF)) for routing packets to an external network or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UE 115 served by a base station 105 associated with the core network 130. User IP packets may be transmitted through 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.

[0136] Some of the network devices (e.g., 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 the UE 115 through multiple other access network transport entities 145 (which may be referred to as radio heads, smart radio heads, or transmit / receive 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).

[0137] 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). Typically, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but the waves may be sufficient to penetrate structures for macro cells to provide service to UEs 115 located indoors. Transmissions using UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0138] The wireless communication system 100 may also operate in a super high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also referred to as a centimeter band) or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also referred to 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 even smaller and more closely spaced than the UHF antenna. In some cases, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may suffer from even greater atmospheric attenuation and shorter distances than SHF or UHF transmissions. The technology disclosed herein may be employed across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may differ according to countries or regulatory agencies.

[0139] The wireless communication system 100 can utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 can employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating in an unlicensed radio frequency spectrum band, devices (such as base stations 105 and UEs 115) can employ carrier sensing for conflict detection and avoidance. In some cases, operations in unlicensed bands can be based on a carrier aggregation configuration in combination with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, D2D transmissions, and the like.

[0140] The base station 105 or UE 115 may be equipped with multiple antennas, which may 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 within one or more antenna arrays or antenna panels (which may support MIMO operations or transmit or receive beamforming). For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, 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 multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0141] The base station 105 or UE 115 can use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. For example, a transmitting device may send multiple signals via different antennas or different combinations of antennas. Similarly, a receiving device may receive multiple signals via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) (where multiple spatial layers are sent to the same receiving device) and multi-user MIMO (MU-MIMO) (where multiple spatial layers are sent to multiple devices).

[0142] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to form or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array so that some signals propagating at a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals transmitted via antenna elements may include the transmitting device or the receiving device applying certain amplitude offsets, phase offsets, or both to signals carried via antenna elements associated with the device. Adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0143] As part of the beamforming operation, the base station 105 or the UE 115 may use beam scanning techniques. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communications with the UE 115. The base station 105 may send some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions. For example, the base station 105 may send signals based on 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 for subsequent transmission and / or reception by the base station 105.

[0144] The base station 105 may determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping may include an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The base station 105 may send information including one or more of the following to the UE 115: a mapping between an SSB and a random access message of a two-step random access procedure, and an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message.

[0145] The UE 115 may determine a mapping between an SSB and, for example, a random access message involving a two-step random access procedure. The UE 115 may also determine an association between one or more corresponding directional beams carrying the SSB and one or more additional corresponding directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message). Additionally, in some examples, the described techniques may include mapping time and frequency resources of the SSB to one or more ROs of the random access preamble and one or more PRUs of the random access payload within a PRACH configuration period in an association pattern period of the two-step random access procedure. Additionally or alternatively, the described techniques may include beam association for a random access fallback procedure and a random access switching procedure.

[0146] Base station 105 may transmit some signals (e.g., data signals associated with a particular receiving device (e.g., UE 115)) in a single beam direction (e.g., a direction associated with the receiving device). In some examples, the beam direction associated with transmissions along the single beam direction may be determined based on signals transmitted in different beam directions. For example, UE 115 may receive one or more of the 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 having the highest signal quality or otherwise acceptable signal quality.

[0147] In some cases, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from 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 send reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may or may not be precoded. 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 of codebook, a linear combination type of codebook, a port selection type of codebook). Although these techniques are described with reference to signals sent by base station 105 in one or more directions, UE 115 may employ similar techniques to send signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115) or to send signals in a single direction (e.g., to send data to a receiving device).

[0148] When receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from the base station 105, the receiving device (e.g., UE 115) can try multiple reception configurations (e.g., directional listening). For example, the receiving device can try multiple reception directions by receiving via different antenna subarrays, by processing the received signals according to different antenna subarrays, by receiving according to different reception beamforming weight sets applied to the signals received at multiple antenna elements of the antenna array (e.g., different directional listening weight sets), or by processing the received signals according to different reception beamforming weight sets applied to the signals received at multiple antenna elements of the antenna array (any of the above operations may be referred to as "listening" according to different reception configurations or reception directions). In some examples, the receiving device can use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned on a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0149] The wireless communication system 100 can be a packet-based network operated according to a layered protocol stack. In the user plane, the communication at the bearer or packet data convergence protocol (PDCP) layer can be based on IP. The radio link control (RLC) layer can perform packet segmentation and reorganization to transmit on a logical channel. The medium access control (MAC) layer can perform priority processing and multiplexing of logical channels to transport channels. The MAC layer can also use error detection technology, error correction technology, or both to support retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection (which supports radio bearers for user plane data) between the UE 115 and the base station 105 or the core network 130. At the physical layer, the transport channel can be mapped to the physical channel.

[0150] UE 115 and base station 105 can support retransmission of data to increase the possibility that data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technology for increasing the possibility that data is correctly received on communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput at the MAC layer under poor radio conditions (e.g., low signal and noise conditions). In some cases, the device can support the same time slot HARQ feedback, wherein the device can provide HARQ feedback for data received in the previous symbol in the time slot in a specific time slot. In other cases, the device can provide HARQ feedback in subsequent time slots or according to some other time interval.

[0151] Figure 2 An example of a wireless communication system 200 supporting a four-step random access procedure according to various aspects of the present disclosure is shown. 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. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. For example, the base station 105-a and the UE 115-a can support robustness for beam association and improvements in random access messaging, among other advantages.

[0152] The base station 105-a can perform a connection process (e.g., an RRC process, such as a cell acquisition process or a random access process) with the UE 115-a. For example, the base station 105-a and the UE 115-a can perform a random access process to establish a connection for communication. In other examples, the base station 105-a and the UE 115-a can perform a random access process to reestablish a connection after a connection failure (e.g., a radio link failure) with the base station 105-a, or establish a connection for switching to another base station, and so on. The base station 105-a and the UE 115-a can also support multiple radio access technologies, including 4G systems such as LTE systems, LTE-A systems, or LTE-A Pro systems, and 5G systems, which can be referred to as NR systems.

[0153] The connection procedure (e.g., random access procedure) between the base station 105-a and the UE 115-a may correspond to, for example, at least one of the above example radio access technologies. Figure 2 In the present invention, the random access process may be related to the 4G system and may be referred to as a four-step random access process. As part of the four-step random access process, the base station 105-a and the UE 115-a may send one or more messages (e.g., one or more handshake messages) such as a random access message 205 (also referred to herein as msg1), a random access message 210 (also referred to herein as msg2), a random access message 215 (also referred to herein as msg3), and a random access message 220 (also referred to herein as msg4).

[0154] exist Figure 2 , the random access process may begin with the UE 115-a sending a random access message 205, which may include a preamble (also referred to as a random access channel (RACH) preamble, a physical random access channel (PRACH) preamble, or a sequence) that may carry information (such as a UE identifier). The purpose of the preamble transmission may be to provide an indication to the base station 105-a of the presence of a random access attempt and to allow the base station 105-a to determine a delay (e.g., a timing delay) between the base station 105-a and the UE 115-a. The UE 115-a may send the random access message 205 to the base station 105-a, for example, on the PRACH.

[0155] In some examples, prior to a connection procedure (such as a four-step random access procedure) between a base station 105-a and a UE 115-a, the base station 105-a may send a synchronization signal block (SSB), a system information block (SIB), a reference signal (e.g., a demodulation reference signal (DMRS)), or a combination thereof to indicate to the UE 115-a configuration information for performing the four-step random access procedure. Some examples of random access procedures (such as a four-step random access procedure) may be contention-based or contention-free. In order to send a random access message and initiate a random access procedure, the UE 115-a may first identify information for the base station 105-a (such as synchronization information) and certain system information for the wireless communication system 200. The base station 105-a may send (e.g., periodically) synchronization information and system information in one or more of the SSBs and the SIBs, respectively. In some examples, the synchronization information and system information may be sent in an SSB and a physical broadcast channel (PBCH) block (e.g., an SS / PBCH block also referred to as an SSB). The base station 105 - a may send a reference signal, such as a DMRS, on the PBCH to assist the UE 115 - a in decoding the SSBs and synchronizing with the base station 105 - a .

[0156] The SSB may include certain synchronization information or signaling that the UE 115-a may use to synchronize downlink communications from the base station 105-a. For example, the SSB may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH. The PBCH may include a master information block (MIB), which may include information indicating the location of a SIB or multiple SIBs. In some examples, a SIB (e.g., SIB1) of the PBCH may include information about transmission opportunities (e.g., resources in time and frequency) for the UE 115-a to send, receive, or send and receive signaling for a random access procedure (such as a RACH or PRACH configuration).

[0157] When performing a contention-based random access (CBRA) procedure, the base station 105-a may configure the UE 115-a to have an association of an SSB to a PRACH opportunity (RO). The RO may be defined as a time and frequency resource on which the UE 115-a may send a random access message in a random access procedure (such as msg1 of a four-step random access message using a configured PRACH preamble format) on a corresponding directional beam. The association may be between a corresponding directional beam carrying an SSB and a corresponding directional beam carrying msg1 of a four-step random access procedure within the RO.

[0158] UE 115-a may receive from base station 105-a a number (N) of SSBs associated within a single RO and a number (R) of contention-based preambles for each SSB of each valid RO, where N and R are positive values. For example, N SS / PBCH blocks associated with one RO and R contention-based preambles for each SS / PBCH block may be provided to UE 115-a via higher layer parameters. In some examples, when N is less than a threshold (e.g., N<1), one SS / PBCH block may be mapped to a fraction of consecutive SSBs for consecutive valid ROs (e.g., 1 / N consecutive valid ROs). Alternatively, when N is greater than or equal to a threshold (e.g., N≥1), N SS / PBCH blocks may be mapped to one valid RO. If N≥1, with R contention-based preambles having consecutive indices associated with SS / PBCH block N, the mapping of each RO may start from the initial preamble index. In some examples, the SS / PBCH block indexes may be mapped to the ROs based in part on, for example, an increasing order of preamble indexes within a single RO, an increasing order of frequency resource indexes for frequency-multiplexed ROs, or an increasing order of time resource indexes for time-multiplexed ROs. The base station 105-a and the UE 115-a may map the SSBs to one or more ROs during one or more PRACH configuration periods of the association mode period. The association mode period may be defined based on one or more PRACH configuration periods.

[0159] The associated mode period for mapping the SS / PBCH block to the RO starting from the initial frame (e.g., frame 0) may be a value in a set determined by the PRACH configuration period according to Table 1, so that the SS / PBCH block is mapped to the RO at least once within the associated mode period. Therefore, Table 1 may show the mapping between the PRACH configuration period and the SS / PBCH block to the RO associated mode period (e.g., the number of PRACH configuration periods).

[0160] Table 1: Mapping between PRACH configuration period and SS / PBCH block to RO associated mode period

[0161] PRACH configuration period (milliseconds) Associated mode period (number of PRACH configuration periods) 10 {1,2,4,8,16} 20 {1,2,4,8} 40 {1,2,4} 80 {1,2} 160 {1}

[0162] In some examples, if there is an RO set that is not mapped to N SS / PBCH blocks after an integer number of SS / PBCH block to RO mapping periods within an association mode period, no SS / PBCH block can be mapped to the RO set. In some examples, the association mode period can include one or more association mode periods and can be determined so that the pattern between RO and SS / PBCH blocks repeats, for example, every 160 milliseconds. ROs that are not associated with SS / PBCH blocks after an integer number of association mode periods (if any) may not be used for PRACH transmission. This document refers to Figure 3 The mapping between the PRACH configuration period and the SS / PBCH blocks to the RO associated mode period is further described in more detail.

[0163] Figure 3 An example of a mapping configuration 300 that supports mapping between one or more PRACH configuration periods and associated mode periods according to various aspects of the present disclosure is shown. The mapping configuration 300 may be implemented as described with reference to Figure 1 and 2 Aspects of the described wireless communication systems 100 and 200. For example, the mapping configuration 300 can be based on the configuration of the base station 105 and implemented by the UE 115 for mapping between one or more PRACH configuration periods and association mode periods to support improvements in robustness for beam association and random access messaging, as well as other advantages, as described herein.

[0164] The mapping configuration 300 may include a PRACH configuration period 305, which may be a portion of a PRACH associated pattern period 310 for SSB to RO mapping. The PRACH configuration period 305 may include a plurality of ROs 320. In some examples, two or more ROs 320 may be frequency division multiplexed. For example, a PRACH slot 315 of the PRACH configuration period 305 may have a plurality of ROs 320 that may be frequency division multiplexed. Figure 3 In the example of , four ROs 320 may be frequency division multiplexed. In some examples, the PRACH configuration period 305 may include multiple periodic frequency division multiplexed ROs 320. For example, every M PRACH time slots 315 may include multiple frequency division multiplexed ROs 320, where M is a positive value.

[0165] In some examples, mapping configuration 300 may be based on the entries of Table 1, such as Figure 2Entries of Table 1 may be based on higher layer parameters, such as, for example, one or more of msg1-FDM and ssb-perRACH-OccasionAndCB-PreamblesPerSSB. For example, the base station 105 may send the higher layer parameters to the UE 115 in a SIB, such as SIB1. Thus, according to the mapping configuration 300, the UE 115 and the base station 105 may map the SSB to the RO to support improvements in robustness for beam association and random access message transmission.

[0166] return Figure 2 In some examples, the preamble of the random access message 205 can be defined by a preamble sequence and a cyclic prefix. The preamble sequence can be defined in part based on a Zadoff-Chu sequence. UE 115-a can additionally or alternatively use a protection period to handle timing uncertainty in the transmission of the random access message 205. For example, before starting the random access process, UE 115-a can obtain downlink synchronization with the base station 105-a based on a cell search process. However, because UE 115-a has not yet obtained uplink synchronization with the base station 105-a, there may be uncertainty in the uplink timing because the position of UE 115-a in the cell (e.g., the geographic coverage area of ​​​​the base station 105-a) is unknown. In some examples, the uncertainty in the uplink timing can be based in part on the dimensions of the cell (e.g., size, area). Therefore, in some examples, including a cyclic prefix in the random access message 205 may be beneficial for handling uncertainty in uplink timing.

[0167] There may be multiple preamble sequences per cell (e.g., 64 preamble sequences). UE 115-a may select a preamble sequence from a set of sequences in a cell (e.g., a geographic coverage area of ​​base station 105-a) based in part on random selection. In some examples, UE 115-a may select a preamble sequence based in part on the amount of traffic that UE 115-a has for transmission on an uplink shared channel (UL-SCH). Based on the preamble sequence selected by UE 115-a, base station 105-a may determine the amount of uplink resources to grant to UE 115-a.

[0168] Some examples of random access procedures may be contention-based or contention-free. When performing a CBRA procedure, UE 115-a may select a preamble sequence from a set of sequences. That is, as long as other UEs (not shown) are not using the same sequence to perform a random access attempt at the same time instance, no conflict will occur and the base station 105-a may detect the random access attempt. If UE 115-a is performing a contention-free random access (CFRA) attempt (e.g., for switching to a new cell), the base station 105-a may explicitly signal (e.g., in control information) the preamble sequence to be used. In order to avoid conflicts or interference, the base station 105-a may select a contention-free preamble sequence from a sequence that is not associated with a contention-based random access attempt.

[0169] After receiving the random access message 205, the base station 105-a may respond appropriately with a random access message 210. For example, the base station 105-a may send the random access message 210 to the UE 115-a on a downlink shared channel (DL-SCH) or a physical downlink control channel (PDCCH). In some examples, the random access message 210 may have the same or a different configuration than the random access message 205. The random access message 210 may carry information for the UE 115-a, where the information is determined by the base station 105-a based on the information carried in the random access message 205. For example, the information in the random access message 210 may include an index of a detected preamble sequence for which the response is valid, a timing advance parameter determined based in part on the detected preamble sequence, a scheduling grant indicating time and frequency resources for transmission by UE 115-a for the next random access message transmission by UE115-a, or a network identifier (e.g., a random access radio network temporary identifier (RA-RNTI)) for further communications with UE115-a, etc.

[0170] In some examples, the base station 105-a may send a random access message 210, which may be scheduled on the PDCCH using an identifier (e.g., RA-RNTI) reserved for random access message transmission. The UE 115-a may monitor the PDCCH to detect and receive a random access message (e.g., random access message 210). In some examples, the UE 115-a may monitor the PDCCH for random access message transmissions from the base station 105-a during a random access response window, which may be fixed or variable in size. For example, if the UE 115-a does not detect and does not receive a random access message transmission from the base station 105-a, the random access attempt may be declared as a failure, and Figure 2The random access procedure in may be repeated. However, in subsequent attempts, the random access response window may be adjusted (eg, increased or decreased in length (duration)).

[0171] Once UE 115-a successfully receives the random access message 210, UE 115-a can obtain uplink synchronization with base station 105-a. In some examples, before data transmission from UE 115-a, a unique identifier within the cell (e.g., cell RNTI (C-RNTI)) can be assigned to UE 115-a. In some examples, depending on the state of UE 115-a (e.g., RRC connection state, RRC ideal state), there may be a need to exchange additional messages (e.g., connection request messages) for establishing a connection between base station 105-a and UE 115-a. UE 115-a can use the UL-SCH resources (or PUSCH resources) assigned in the random access message 210 to send any necessary messages to base station 105-a, such as random access message 215. The random access message 210 may include a UE identifier for contention resolution. For example, if UE 115-a is in an RRC connection state, the UE identifier may be a C-RNTI. Otherwise, the UE identifier may be specific to UE 115-a.

[0172] The base station 105-a may receive the random access message 215 and may respond appropriately, for example, by sending a random access message 220 (which may be a contention resolution message). When multiple UEs (including UE 115-a) are performing random access attempts simultaneously using the same preamble sequence, these UEs may cause the same response message (e.g., random access message 220) to be listened to. Each UE (including UE 115-a) may receive the random access message 220 and compare the identifier (e.g., network identifier) ​​in the random access message 220 with the identifier specified in the random access message 215. When the identifiers match, the corresponding UE (e.g., UE 115-a) may declare that the random access process is successful. A UE that does not identify a match between the identifiers is deemed to have failed the random access process and may repeat the random access process with the base station 105-a. As a result of the connection process, the base station 105-a and the UE 115-a may establish a connection for communication.

[0173] although Figure 2The connection process (e.g., random access process) in the UE 115-a may be effective in facilitating random access for the UE 115-a, but there may be unnecessary delays associated with the process. For example, delays associated with a contention-based protocol for random access message transmission may exhaust additional resources of the UE 115-a. The techniques described herein can provide benefits to the UE 115-a by reducing or eliminating delays associated with processes related to initial channel access.

[0174] Figure 4 An example of a wireless communication system 400 supporting a two-step random access procedure according to various aspects of the present disclosure is shown. The wireless communication system 400 may include a base station 105-b and a UE 115-b, which may be referenced Figure 1 Examples of corresponding devices described. In some examples, the wireless communication system 400 can implement aspects of the wireless communication systems 100 and 200. For example, the base station 105-b and the UE 115-b can support improvements in robustness for beam association and random access messaging, among other advantages.

[0175] As reference Figure 2 As explained, the base station 105-b and the UE 115-b may support a variety of radio access technologies, including a 4G system such as an LTE system, an LTE-A system, or an LTE-A Pro system, and a 5G system which may be referred to as an NR system. The connection process (e.g., a random access process) between the base station 105-b and the UE 115-b may correspond to, for example, at least one of these example radio access technologies. Figure 4 In the example of , the random access procedure may be related to a 5G system and may be referred to as a two-step random access procedure. As part of the two-step random access procedure, in order to reduce latency associated with the contention-based aspects of the two-step random access procedure, the base station 105-b and the UE 115-b may exchange fewer messages (e.g., handshake messages) (compared to the example in Figure 2 compared to the four-step random access procedure explained in ).

[0176] For example, the UE 115-b may send a single message, such as a random access message 405 (also referred to herein as msgA), and the base station 105-b may send a single message, such as a random access response message 410 (also referred to herein as msgB) in response to the random access message 405. The random access message 405 (e.g., msgA) may combine portions of msg1, 3 of the four-step random access procedure, and the random access response message 410 (e.g., msgB) may combine aspects of msg2, 4 of the four-step random access procedure. When supporting both the two-step random access procedure and the four-step random access procedure, it may be important to have the UE 115-b configured to support beam association for both random access procedures.

[0177] When both the two-step random access procedure and the four-step random access procedure are supported, the base station 105-b and the UE 115-b can start with one random access procedure (e.g., the two-step random access procedure) and, if necessary, fall back to another random access procedure (e.g., the four-step random access procedure). The base station 105-b can select or assign priorities to the random access procedure based on conditions (e.g., traffic type, network load). For example, the base station 105-b can be configured to use a four-step random access procedure instead of a two-step random access procedure for certain scenarios (e.g., traffic load, link quality measurement, system load, quality of service (QoS), etc.) to reduce overhead, because the base station 105-b may have to provide msgA resources for two-step random access that may involve greater overhead compared to msg1 transmission using the four-step random access procedure. Additionally or alternatively, the base station 105-b may select a random access procedure based on the ability of the UE 115-b to support the random access procedure. For example, if UE 115-b supports both the two-step random access procedure and the four-step random access procedure, base station 105-b may select the two-step random access procedure or the four-step random access procedure to start the initial access procedure. Otherwise, base station 105-b may select the random access procedure supported by UE 115-b.

[0178] Returning to the example of random access message transmission, UE 115-b can send a random access message 405 to base station 105-b. Random access message 405 can include a random access preamble and a random access payload (e.g., a physical uplink shared channel (PUSCH) carrying the payload), wherein the information in random access message 405 (e.g., msgA) includes equivalent content or aspects of msg3 of the four-step random access procedure. Figure 5 The transmission of the random access message 405 in the two-step random access procedure is further described in more detail.

[0179] Figure 5An example of a transmit chain 500 that supports beam association in a random access procedure according to aspects of the present disclosure is shown. In some examples, the transmit chain 500 can implement aspects of the wireless communication system 400. For example, referring to Figure 4 , the transmission chain 500 can illustrate how the UE 115-b configures (e.g., encodes, scrambles, maps, etc.) a random access message 405 (e.g., msgA) of a two-step random access process before the UE 115-b sends it to the base station 105-b. The UE 115-b can use the encoder 505 to encode the payload portion of the random access message 405. In some examples, the encoder 505 can be a low-density parity check (LDPC) encoder. After encoding the payload of the random access message 405, the UE 115-b can pass the payload through a scrambler 510, which can scramble the encoded bits. After scrambling the encoded bits, the UE 115-v can then perform modulation 515. In some examples, the modulation 515 can include linear modulation.

[0180] Subsequently, the UE 115-b may perform precoding 520 (e.g., transform precoding) on ​​the modulated bits. Then, the UE 115-b may transform the bits using an inverse fast Fourier transform (IFFT) 525 after precoding. After the IFFT 525, the UE 115-b may use a multiplexer (MUX) 530. In some examples, using the multiplexer 530, the UE 115-b may multiplex the DMRS 545 (e.g., in reference signal resources and using a DMRS sequence, as described herein). Subsequently, the UE 115-b may perform mapping 535. In some examples, the UE 115-b may perform mapping based on the preamble 540. For example, the preamble 540 may indicate one or more of a predefined mapping rule between the preamble of the random access message 405 and the payload, a reference signal resource, and a reference signal sequence. In some examples, the mapping may include mapping of time, frequency, and spatial (e.g., beam, panel) resources. The preamble 540 may provide an advance indication of user plane data, control plane data, medium access control (MAC) control elements (CEs) (MAC CEs) (e.g., including buffer status reports (BSRs) or power headroom reports (PHRs)), payload size, and uplink control information (UCI) piggybacked on the PUSCH. The UE 115 - b may then send the random access message 405 after performing different steps.

[0181] return Figure 4An advantage of the two-step random access procedure over the four-step random access procedure may be that UE 115-b is able to send data (e.g., a random access payload on the PUSCH) to base station 105-b without having to be in an RRC connected state for a data transmission. Base station 105-b may monitor PUSCH for a random access preamble or a random access payload of random access message 405. In some examples, base station 105-b may determine based on the monitoring that a random access preamble or a random access payload of random access message 405 is not present. The absence of a random access preamble or a random access payload of random access message 405 may cause the random access procedure to fail.

[0182] In some examples, after successfully receiving the random access message 405, the base station 105-b may construct a random access response message 410 and send it to the UE 115-b. For example, the base station 105-b may send the random access response message 410 to the UE 115-b on the DL-SCH, PDSCH, PDCCH. The random access response message 410 may include at least one of a network identifier of the UE 115-b, a timing advance parameter, and a backoff indication for the UE 115-b. The backoff indication may include a timing backoff indication or a random access process backoff indication, or both. The timing backoff indication may be associated with the timing of retrying a random access process (e.g., a two-step random access process), and the random access process backoff indication may be associated with switching from a current random access process to an alternative random access process (e.g., a four-step random access process).

[0183] In an example of a multi-beam implementation of a random access procedure (e.g., such as a two-step random access procedure), transmission of a random access preamble on a PRACH and transmission of a PUSCH carrying a random access payload may occur within one or more opportunities. For example, transmission of a random access preamble on a PRACH may occur within a RO, which may include time and frequency resources. In other examples, transmission of a PUSCH carrying a random access payload may occur within a PO, which may include time and frequency resources (e.g., a PURSH resource unit (PRU) including PUSCH resources and DMRS resources).

[0184] One or more opportunities may share a relationship. In some examples, RO and PO may have a one-to-one mapping. For example, a single RO may be mapped to a single corresponding PO. In some other examples, RO and PO may have a one-to-many mapping. For example, a single RO may be mapped to several POs. Alternatively, multiple ROs may be mapped to a single PO using a many-to-one mapping. UE115-b may multiplex the transmission of random access preambles on the time and frequency resources of multiple ROs. Similarly, it may be advantageous to enable UE115-b to multiplex the transmission of PUSCH carrying random access payloads on the time and frequency resources of multiple POs.

[0185] In some examples, when both the two-step random access procedure and the four-step random access procedure are supported, the base station 105-b can configure separate ROs for the two-step random access procedure and the four-step random access procedure. Alternatively, the base station 105-b can configure a shared RO, but configure (use) separate preambles for the two-step random access procedure and the four-step random access procedure to avoid interference issues. In some examples, when both the two-step random access procedure and the four-step random access procedure are supported, the base station 105-b and the UE 115-b can configure beam establishment during initial access for the two-step random access procedure for improved coverage and interference mitigation.

[0186] In some examples, when supporting both the two-step random access procedure and the four-step random access procedure, the base station 105-b and the UE 115-b are able to perform beam switching for random access message retransmission (e.g., msgA retransmission) and fall back to a different random access procedure (e.g., from a two-step random access procedure to a four-step random access procedure). In order to improve the reliability of beam establishment for different random access procedures (e.g., two-step random access procedures) and reduce the complexity in the wireless communication system 400, the base station 105-b and the UE 115-b can support resource configuration and signaling support for beam association between SSBs and random access message transmission resources (e.g., msgARO and msgA PRU). One or more SSBs and one or more ROs can share a relationship. In some examples, the SSB and the RO can have a one-to-one mapping. For example, a single SSB can be mapped to a single corresponding RO. In some other examples, the SSB and the RO may have a one-to-many mapping. For example, a single SSB can be mapped to several ROs. Alternatively, multiple SSBs can be mapped to a single RO using a many-to-one mapping. The base station 105-b may multiplex the transmission of SSBs over the time and frequency resources of multiple ROs. Similarly, the respective directional beams associated with the SSBs may have a relationship (association) with the respective directional beams associated with the ROs (and / or POs).

[0187] In some examples, the base station 105-b and the UE 115-b may map the SS / PBCH blocks to the RO according to Table 2, which may implement aspects of Table 1 such that the SS / PBCH blocks are mapped to the RO at least once within an associated mode period during a two-step random access procedure. Thus, Table 2 may illustrate mapping capabilities between a PRACH configuration period and an SS / PBCH block to a RO associated mode period for both a two-step random access procedure and a four-step random access procedure. In some examples, the associated mode period of the two-step random access procedure may be a multiple of the associated mode period of the four-step random access procedure (e.g., the two-step random access procedure associated mode period K*four-step random access process associated mode period, where K≥1 and K is an integer).

[0188] Table 2: Mapping between PRACH configuration period and SS / PBCH block to RO associated mode period

[0189]

[0190] This article refers to Fig. 6A and 6B Resource configuration and signaling support for beam association between SSB and random access message transmission resources are further described in more detail.

[0191] Fig. 6A An example of a channel structure 600-a supporting beam association in a random access procedure in accordance with various aspects of the present disclosure is shown. The channel structure 600-a can implement various aspects of the wireless communication systems 100, 200, and 400. For example, the channel structure 600-a can support improvements in robustness for beam association and random access message transmission, as well as other advantages, as described herein. The UE 115 can send a random access message 605 to the base station 105 based on the channel structure 600-a. The random access message 605 can represent the structure of a random access message (e.g., msgA) for a two-step random access procedure as described herein. The channel structure 600-a of the random access message 605 can support a CBRA procedure or a CFRA procedure on time and frequency resources.

[0192] The random access message 605 may include a random access preamble 610 and a random access payload 615. In some examples, the bandwidth used for the random access preamble 610 and the random access payload 615 may be the same or different. The random access preamble 610 may include a PRACH preamble signal 620, wherein the random access preamble 610 (e.g., having the PRACH preamble signal 620) may be used for a variety of purposes. For example, the random access preamble 610 may facilitate timing offset estimation by the base station 105. In addition, the random access preamble 610 may provide an advance indication of the payload size and resource allocation for the random access payload 615 (e.g., this may provide a more efficient solution than piggybacking UCI on a PUSCH including the random access payload 615).

[0193] In some examples, resource allocation for the random access payload 615 can be based on a predefined mapping rule between the random access preamble 610 and the random access payload 615, which can be indicated in the configuration information from the base station 105. The random access payload 615 may include a DMRS / PUSCH 635 portion for transmission of the random access payload 615 of the random access message 605. The random access payload 615 may include a configurable payload size for different use cases and RRC states. For example, the random access payload 615 may include a minimum payload size and may not include a maximum (e.g., upper limit) payload size. In some examples, the random access payload 615 may include data from one or more of a user plane and a control plane.

[0194] In addition, between each part of the random access message 605 (e.g., between the random access preamble 610 and the random access payload 615), there can be a guard time (GT) 625. There can be a first GT 625-a between the random access preamble 610 and the random access payload 615, and there can be a second GT 625-b after the random access payload 615 and the subsequent random access preamble 610. In addition, the base station 105 can also configure a transmission gap (e.g., TxG) 630 to extend the time between the random access preamble 610 and the random access payload 615. The transmission gap 630 can extend the random access message 605 to occur over more than one symbol (e.g., or different TTI lengths). In some examples, each GT 625 can have a length equal to T G The transmission gap 630 may have a duration equal to T gIn some examples, the base station 105 can configure a guard band (GB) 640. For example, the base station 105 can configure a first GB 640-a and a second GB 640-b to mitigate inter-symbol interference (ISI) or inter-carrier interference (ICI) for asynchronous uplink communications.

[0195] Figure 6B An example of a mapping configuration 600-b that supports beam association in a random access process in accordance with various aspects of the present disclosure is shown. The mapping configuration 600-b can implement various aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 600-b can support improvements in robustness for beam association and random access message transmission, as well as other advantages, as described herein. The base station 105 can configure a mapping between an SSB 650 and one or more PRACHs 655 of a random access preamble of a random access message (e.g., msgA) within one or more ROs and one or more PRUs 660 of a random access payload of the random access message (e.g., msgA), and the UE 115 can determine the mapping based on the configuration of the base station 105.

[0196] During the association mode period, the base station 105 can configure a time slot that includes one or more PRACHs 655 within one or more ROs and one or more random access payloads on one or more PRUs 660, etc. In some examples, the base station 105 can associate (e.g., using parameter association) one or more SSBs 650 with one or more PRACHs 655 and one or more PRUs 660 during the PRACH association mode period. For example, a first SSB 650-a can be associated with a first PRACH 655 and a first PRU 660, while a second SSB 650-b can be associated with a second PRACH 655 and a second PRU 660. In some examples, the UE 115 can determine, based on the mapping, an association between one or more corresponding directional beams carrying the SSBs 650 and one or more additional corresponding directional beams carrying the PRACH 655 (e.g., a random access preamble of a random access message (e.g., msg A)) and a random access payload of the random access message (e.g., msg A). In some examples, base station 105 and UE 115 can support different beam associations between SSB and random access messages (e.g., msgA) of a two-step random access procedure.

[0197] In some examples, to support different beam associations between SSB and msgA, the base station 105 may send configuration information for beam association to the UE 115 via SIB signaling or RRC signaling. The UE 115 may determine the beam association based on one or more factors. For example, the UE 115 may determine the association between one or more corresponding directional beams carrying the SBB 650 and one or more additional corresponding directional beams carrying the random access message (e.g., msgA) based in part on the RO index of one or more ROs. In some examples, the UE 115 may determine the association between one or more corresponding directional beams carrying the SBB 650 and one or more additional corresponding directional beams carrying the random access message (e.g., msgA) based in part on the preamble sequence of the random access preamble of the random access message (e.g., msgA). In some examples, the UE 115 may determine the association between one or more corresponding directional beams carrying the SBB 650 and one or more additional corresponding directional beams carrying the random access message (e.g., msgA) based in part on the PRU index associated with one or more PRUs. In some other examples, UE 115 can determine an association between one or more corresponding directional beams carrying SBB 650 and one or more additional corresponding directional beams carrying a random access message (e.g., msgA) based in part on the UCI piggyback of the PUSCH. Thus, UE 115 can determine the beam association based on one or more factors such as msgA RO index, msgA preamble sequence, msgA PRU index, and UCI piggyback.

[0198] The random access preamble and the random access payload of the random access message (e.g., msgA) of the two-step random access procedure may be associated with different SSBs 650. For example, referring to Fig. 6A , when T g and T G The sum of (for example, T g +T G ) is greater than the threshold, the random access preamble and random access payload of the random access message (e.g., msgA) of the two-step random access procedure may be associated with different SSBs 650. For example, referring to Fig. 6A and 6B , the random access preamble 610 (carried on the PRACH 655) can be associated with the SSB 650-a, while the random access payload 615 (and the PRU 660) can be associated with the SSB 650-b. In some examples, one or more PRUs 660 that share time domain resources can be grouped together and can be mapped to the same SSB 650 or the same subset of SSBs 650.

[0199] For example, the UE 115 may determine that one or more PRUs 660 of the random access payload share time / frequency resources, and determine a mapping between the one or more PRUs 660 of the shared time / frequency resources of the random access payload and an SSB 650 or a subset of SSBs in a set of SSBs 650. The SSB subsets may be grouped. In some examples, the base station 105 and the UE 115 may map the one or more PRUs 660 of the shared time / frequency resources of the random access payload to one or more SSBs 650 based in part on analog beamforming capabilities or digital beamforming capabilities. For example, for analog beamforming, the base station 105 and the UE 115 may support mapping to a single SSB, while for digital beamforming, the base station 105 and the UE 115 may support mapping to more than one SSB.

[0200] return Figure 4 In some examples, the base station 105-b and the UE 115-b may support sharing of the RO between multiple random access procedures. For example, the base station 105-b and the UE 115-b may support sharing of the RO between a two-step random access procedure and a four-step random access procedure. In some examples, the base station 105-b may configure sharing of the RO between multiple random access procedures based on system information signaling or RRC signaling. The base station 105-b may determine to configure RO sharing between multiple random access procedures based on one or more conditions. For example, the base station 105-b may determine to configure RO sharing based on one or more of the following: UE capability of the UE 115-b, random access procedure fallback capability of the UE 115-b, load balancing capability (e.g., for more efficient RO sharing), or multiplexing of CFRA and CBRA.

[0201] UE 115-b may receive, from base station 105-b, a number N of SSBs associated with one or more shared ROs between multiple random access procedures. In some examples, the mapping of SSBs to one or more shared ROs may be based on whether the number N of SSBs is equal to or greater than a threshold (e.g., N≥1). In some examples, the preamble sequence may vary between random access messages of multiple random access procedures. For example, when the number N of SSBs is equal to a threshold (e.g., N=1), the preamble sequence of a random access message (e.g., msgA) of a two-step random access procedure and the preamble sequence of a random access message (e.g., msg1) of a four-step random access procedure may be configured to have two preamble sequence subsets.

[0202] In some examples, UE 115-b can determine that the number N of SSBs satisfies a threshold, and determine that the random access preamble of a random access message (e.g., msgA) of a two-step random access process and a random access message (e.g., msg1) of a four-step random access process are configured to have different preamble sequence subsets. In some examples, the index of the preamble sequence in each subset can be consecutive. Therefore, UE 115-b can determine that the index of the preamble sequence in each subset of the preamble sequence subsets (e.g., msgA and msg1) is consecutive. In some examples, the preamble sequences in each subset can be non-overlapping to avoid interference. Therefore, the base station 105-b can use the same corresponding directional beam to receive two random access messages, for example, msgA associated with the two-step random access message and msg1 associated with the four-step random access message. This article refers to Fig. 7A The beam association between SSB and random access message transmission resources is further described in more detail.

[0203] Fig. 7A An example of a mapping configuration 700-a that supports beam association in a random access procedure in accordance with various aspects of the present disclosure is shown. The mapping configuration 700-a can implement various aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 700-a can support improvements in robustness for beam association and random access message transmission, as well as other advantages, as described herein. The base station 105 can send an SSB 705-a to the UE 115 on the same corresponding directional beam 725-a. The SSB 705-a can correspond to a random access preamble 710-a of a random access message associated with a two-step random access procedure (e.g., msgA) and a random access message 715-a associated with a four-step random access procedure (e.g., msg1). The random access preamble 710-a of a random access message associated with a two-step random access procedure (e.g., msgA) and the random access message 715-a associated with a four-step random access procedure (e.g., msg1) can share the RO 720-a and can be configured with different preamble sequences, as described herein. Therefore, due to the use of different preamble sequences (which can distinguish the transmissions), the base station 105 can also receive the random access preamble 710-a of the random access message associated with the two-step random access procedure (e.g., msgA) and the random access message 715-a associated with the four-step random access procedure (e.g., msg1) from the UE 115 on the same corresponding directional beam.

[0204] return Figure 4In some examples, UE 115-b may determine that the number N of SSBs is above a threshold (e.g., N>1), and determine the random access preamble of a random access message (e.g., msgA) of a two-step random access procedure and the random access message (e.g., msg1) of a four-step random access procedure. In an example where the number N of SSBs is above the threshold, the base station 105-b may configure (e.g., map) the number N of SSBs to the same RO, which may be shared by the random access preamble of the random access message (e.g., msgA) of the two-step random access procedure and the random access message (e.g., msg1) of the four-step random access procedure. In some examples, the base station 105-b may use different corresponding directional beams for the number N of SSBs. In some examples, the random access preamble of the random access message (e.g., msgA) of the two-step random access procedure and the random access message (e.g., msg1) of the four-step random access procedure may be mapped to different SSB subsets. The mapping to the SSB subsets may be continuous or discontinuous in the time domain. In some examples, depending on the spatial separability of the corresponding directional beams mapped to the random access message of the two-step random access procedure (e.g., msgA) and the random access message of the four-step random access procedure (e.g., msg1), the preamble code sequence subsets associated with each corresponding directional beam can have similar or different sizes. The base station 105-b can adopt different corresponding directional beams to receive the random access message of the two-step random access procedure (e.g., msgA) and the random access message of the four-step random access procedure (e.g., msg1) from the UE 115-b. This document refers to Figure 7B The beam association between SSB and random access message transmission resources is further described in more detail.

[0205] Figure 7BAn example of a mapping configuration 700-b that supports beam association in a random access procedure in accordance with various aspects of the present disclosure is shown. The mapping configuration 700-b can implement various aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 700-b can support improvements in robustness for beam association and random access message transmission, as well as other advantages, as described herein. When supporting multiple random access procedures, the base station 105 can send different SSBs 705 to the UE 115-b on the same or different corresponding directional beams 725. For example, the base station 105 can send SSB 705-b on a corresponding directional beam 725-b of a random access preamble 710-b corresponding to a random access message associated with a two-step random access procedure, and send SSB 705-c on a corresponding directional beam 725-c corresponding to a random access message 715-b associated with a four-step random access procedure. Alternatively, the base station 105 may transmit an SSB 705-b corresponding to a random access preamble 710-b of a random access message associated with a two-step random access procedure and an SSB 705-c corresponding to a random access message 715-b associated with a four-step random access procedure on the same respective directional beams 725-d. The random access preamble 710-a of a random access message associated with a two-step random access procedure (e.g., msgA) and a random access message 715-b associated with a four-step random access procedure (e.g., msg1) may share an RO 720-b and may be configured to have different preamble sequences, as described herein. Thus, due to the use of different preamble sequences (which can distinguish the transmissions), the base station 105 can also receive the random access preamble 710-b of a random access message associated with a two-step random access procedure (e.g., msgA) and the random access message 715-b associated with a four-step random access procedure (e.g., msg1) from the UE 115 on the same corresponding directional beam.

[0206] return Figure 4In some examples, during the association mode period of the two-step random access process, UE 115-b can retransmit the random access message 405 (e.g., the random access preamble and the random access payload of the random access message 405) multiple times. In some examples, UE 115-b can retransmit the random access message 405 as long as the retransmission counter is below a threshold (e.g., a maximum value configured by the base station 105-b). The base station 105-b and the UE 115-b can support beam switching, for example, switching the corresponding directional beams used for retransmission of the random access message 405 (e.g., the receiving beam of the base station 105-b and the transmitting beam of the UE 115-b). In some examples, UE 115-b can support beam switching for both the random access preamble of the random access message 405 and the random access payload of the random access message 405 (e.g., switching the transmitting beam). Similarly, the base station 105-b may support beam switching (e.g., switching receive beams) for both the random access preamble of the random access message 405 and the random access payload of the random access message 405. In some examples, beam switching (e.g., transmit beam switching) may be indicated based on one or more conditions such as one or more of the following: a change in RO index, a change in PRU index, a change in preamble index of the random access preamble of the random access message 405, or UCI piggybacking on the PUSCH.

[0207] In some examples, based on the RRC state (e.g., RRC idle state, RRC inactive state), the resources (e.g., pre-configured in the time domain, frequency domain, spatial domain, code domain) used for transmission and retransmission of the random access message 405 may be different. For example, if the random access message 405 is allowed to be retransmitted M times within the associated mode period of the two-step random access procedure, then when 1≤retransmission counter , UE 115-b may use resources in the first resource set X. Alternatively, when ≤ retransmission counter ≤ M, UE 115-b may use resources in a second resource set Y, where the first resource set is different from the second resource set. In some examples, for the RRC connected state, a reference signal (e.g., a channel state information (CSI) reference signal, a sounding reference signal) may be configured to assist beam switching. In some examples, the base station 105-b and the UE 115-b may jointly perform beam switching (e.g., jointly perform receive beam and transmit beam switching). In some examples, the base station 105-b and the UE 115-b may enable beam switching based in part on an association rule between an SSB and a resource mapping of a random access message 405, or triggered by a preamble, a reference signal, or a UCI.

[0208] The base station 105-b and the UE 115-b may support beam switching for a random access fallback procedure or a random access switching procedure from a two-step random access procedure to a four-step random access procedure. For example, when a fallback for switching occurs, a new transmission may start with msg1 or msg3 of a four-step random access procedure. In some examples, beam switching may be enabled for a random access fallback procedure or a random access switching procedure. For example, when a new transmission starts with msg3 of a four-step random access procedure, the base station 105-b may command beam switching via downlink control information (DCI). Alternatively, when a new transmission starts with msg1 of a four-step random access procedure, beam switching may be pre-configured based on an association rule between SSB and RO. Thus, the described technology may include features for improved resource utilization and allocation for random access message transmission, improved reliability for random access message transmission, and in some examples, may facilitate low latency for a random access procedure, as well as other benefits.

[0209] Figure 8 An example of a process flow 800 for supporting beam association in a random access procedure according to aspects of the present disclosure is shown. In some examples, the process flow 800 may be implemented as described with reference to Figure 1 , 2 4. For example, the process flow 800 may include a base station 105-c and a UE 115-c, which may be referenced to Figure 1 and 2 Examples of corresponding devices described. In the following description of process flow 800, operations between base station 105-c and UE 115-c may be sent in an order different from the example order shown, or operations performed by base station 105-c and UE 115-c may be performed in a different order or at a different time. Some operations may also be omitted from process flow 800, and other operations may be added to process flow 800. The operations performed by base station 105-c and UE 115-c may support improvements in UE 415 resource usage and allocation for random access message transmission, improved reliability for random access message transmission, and in some examples, may facilitate low latency for random access procedures, among other benefits.

[0210] The process flow 800 may begin with the base station 105-c and the UE 115-c performing a random access procedure to establish a connection. The base station 105-c and the UE 115-c may support a variety of radio access technologies, including a 4G system such as an LTE system, an LTE-A system, or an LTE-APro system, and a 5G system which may be referred to as an NR system. The random access procedure may correspond to, for example, at least one of the above example radio access technologies. Figure 8 For example, the random access procedure may be a four-step random access procedure associated with a 4G system or a two-step random access procedure associated with a 5G NR system, etc. Alternatively, the random access procedure occurs after one or more operations of process flow 800.

[0211] At 805, the base station 105-c may determine a mapping between an SSB and a random access message of a random access procedure (e.g., such as a two-step random access procedure). In some examples, the base station 105-c may determine an association between one or more beams carrying the SSB and one or more additional beams carrying, for example, a random access preamble and a random access payload of a random access message based in part on the mapping. The base station 105-c may map resources of the SSB to one or more ROs of a random access preamble of the random access message and one or more PRUs of a random access payload within a PUSCH configuration period in an association mode period of the random access procedure. At 810, the base station 105-c may send signaling (e.g., mapping and association information) including the configuration to the UE 115-c. In some examples, the signaling may include system information signaling, RRC signaling, etc. At 815, the UE 115-c may determine a mapping between an SSB and a random access message of the random access procedure, for example, based in part on the signaling. At 820, the UE 115-c may determine an association between one or more beams carrying the SSB and one or more additional beams carrying the random access message.

[0212] At 825, the base station 105-c and the UE 115-c may continue the random access procedure. For example, the base station 105-c may send one or more SSBs to the UE 115-c on one or more corresponding directional beams corresponding to one or more ROs. The random access procedure may also enable the UE 115-c to send a random access message (also referred to as msgA) to the base station 105-c. When the random access procedure is a two-step random access procedure, the msgA sent from the UE 115-c may include a preamble and a random access payload. For example, as part of the random access procedure, the UE 115-c may send msgA using a preamble (also referred to as a RACH preamble, a PRACH preamble, or a sequence). In some examples, the msgA may include a UE identifier in the msgA so that the base station 105-c can identify the UE 115-c among other UEs. The UE 115-c may send msgA on one or more corresponding directional beams based on mapping and beam association. The base station 105-c may send a random access message (also referred to as msgB) to the UE 115-c. msgB may be a random access response to a random access message (e.g., msgA) received from the UE 115-c. In some examples, the base station 105-c may send msgB to the UE 115-c based in part on a UE contention resolution identifier, a RA-RNTI, etc. For example, as part of a random access procedure, the UE 115-c may send msgB on the DL-SCH based on the RA-RNTI. The base station 105-c may send msgB on one or more corresponding directional beams based on mapping and beam association.

[0213] Fig. 9 A block diagram 900 of a device 905 supporting beam association in a random access procedure according to 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 UE communication manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0214] 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 association in a random access process, etc.). The information may be communicated to other components of the device 905. The receiver 910 may be a reference Fig.12 Examples of various aspects of the transceiver 1220 are described. The receiver 910 may utilize a single antenna or a group of antennas.

[0215] The UE communication manager 915 may perform the following operations: determine, based on an indication in system information signaling or RRC signaling, a mapping between an SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determine, based on the mapping, an association between one or more beams carrying the SSB and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and perform a two-step random access procedure with a base station. The UE communication manager 915 may be an example of aspects of the UE communication manager 1210 described herein.

[0216] The UE 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 UE communication manager 915 or its subcomponents may be performed by a general purpose processor, DSP, application specific integrated circuit (ASIC), FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0217] The UE communication manager 915 or its subcomponents may be physically located at various locations, including being distributed so that part of the functions are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the UE communication manager 915 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the UE 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, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0218] The transmitter 920 can transmit signals generated by other components of the device 905. In some examples, the transmitter 920 can be co-located with the receiver 910 in a transceiver module. For example, the transmitter 920 can be a reference Fig.12 Examples of various aspects of the transceiver 1220 are described. The transmitter 920 may utilize a single antenna or a group of antennas.

[0219] Fig.10A block diagram 1000 of a device 1005 supporting beam association in a random access procedure according to 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 UE communication manager 1015, and a transmitter 1035. The device 1005 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0220] 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 association in a random access process, etc.). The information may be communicated to other components of the device 1005. The receiver 1010 may be a reference Fig.12 Examples of various aspects of the transceiver 1220 are described. The receiver 1010 may utilize a single antenna or a group of antennas.

[0221] The UE communication manager 1015 may be an example of aspects of the UE communication manager 915 as described herein. The UE communication manager 1015 may include a mapping component 1020, an association component 1025, and an access component 1030. The UE communication manager 1015 may be an example of aspects of the UE communication manager 1210 described herein.

[0222] The mapping component 1020 can determine, based on the indication, a mapping between the SSB and a random access message of a two-step random access procedure, the random access message comprising a random access preamble and a random access payload. The association component 1025 can determine, based on the mapping, an association between one or more beams carrying the SSB and one or more additional beams carrying a random access preamble and a random access payload of the random access message. The access component 1030 can perform a two-step random access procedure with the base station.

[0223] The transmitter 1035 can transmit signals generated by other components of the device 1005. In some examples, the transmitter 1035 can be co-located with the receiver 1010 in a transceiver module. For example, the transmitter 1035 can be a reference Fig.12 Examples of various aspects of the transceiver 1220 are described. The transmitter 1035 can utilize a single antenna or a group of antennas.

[0224] Fig.11A block diagram 1100 of a UE communication manager 1105 supporting beam association in a random access procedure in accordance with aspects of the present disclosure is shown. The UE communication manager 1105 may be an example of aspects of the UE communication manager 915, the UE communication manager 1015, or the UE communication manager 1210 described herein. The UE communication manager 1105 may include a mapping component 1110, an association component 1115, an access component 1120, a signaling component 1125, a resource component 1130, a threshold component 1135, a sequence component 1140, a beam component 1145, and a backoff component 1150. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0225] The mapping component 1110 may determine a mapping between an SSB and a random access message of a two-step random access procedure based on the indication, the random access message comprising a random access preamble and a random access payload. In some examples, the mapping component 1110 may map resources of the SSB to one or more ROs of the random access preamble and one or more PRUs of the random access payload within a PRACH configuration period in an association mode period of the two-step random access procedure. In some examples, the mapping component 1110 may determine an association mode period of the two-step random access procedure based on a second indication, wherein the association mode period of the two-step random access procedure is based on a factor value of an association mode period of a four-step random access procedure, the factor value comprising an integer value within a limited range configured by the network.

[0226] In some examples, the mapping component 1110 may determine a mapping between one or more PRUs of a shared time / frequency resource of a random access payload and one of the SSBs or a portion of the SSBs in the SSBs, wherein the portion of the SSBs in the SSBs is grouped. In some examples, the mapping component 1110 may map one or more PRUs of a shared time / frequency resource of a random access payload to the SSB in the SSBs based on an analog beamforming capability. In some examples, the mapping component 1110 may map one or more PRUs of a shared time / frequency resource of a random access payload to the portion of the SSBs in the SSBs based on a digital beamforming capability. In some cases, based on a guard period associated with a random access preamble and a duration of a gap period between the random access preamble and the random access payload, a random access preamble and a random access payload of a random access message are associated with different SSBs in the SSBs. In some cases, a random access preamble of a two-step random access procedure and a random access message of a four-step random access procedure are mapped to different SSBs in a plurality of SSBs.

[0227] The association component 1115 can determine, based on the mapping, an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. In some examples, the association component 1115 can determine a second association between the one or more beams carrying the SSB and the one or more additional beams carrying the random access preamble and the random access payload of the random access message within an additional PRACH configuration period of a second association pattern period of the two-step random access procedure. In some examples, the second association within the second association pattern period of the two-step random access procedure can be different from the association within the association pattern period of the two-step random access procedure.

[0228] In some examples, an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message is determined based on a physical random access channel timing index of one or more ROs, wherein the indication includes a physical random access channel timing index. In some examples, an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message is determined based on a preamble sequence of the random access preamble, wherein the indication includes a preamble sequence. In some examples, an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message is determined based on a physical uplink shared channel resource unit index associated with one or more PRUs of the random access payload, wherein the indication includes a physical uplink shared channel resource unit index. In some examples, an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message is determined based on multiplexing UCI into one or more of a random access preamble and a random access payload of a random access message, wherein the indication includes multiplexing of UCI.

[0229] The access component 1120 can perform a two-step random access procedure with the base station. In some examples, the access component 1120 can send a random access message of the two-step random access procedure to the base station during the association mode period. In some examples, the access component 1120 can retransmit the random access message of the two-step random access procedure during the association mode period based on the retransmission counter being less than a threshold.

[0230] The signaling component 1125 may receive signaling from a base station including an indication including an association between one or more beams carrying an SSB and one or more additional beams carrying a random access preamble and a random access payload of a random access message. In some cases, the signaling includes system information signaling. In some cases, the signaling includes RRC signaling.

[0231] The resource component 1130 may determine that one or more PRUs of the random access payload share time / frequency resources. In some examples, the resource component 1130 may determine that one or more ROs of the random access preamble are shared with one or more additional random access preambles of the four-step random access procedure. In some examples, the resource component 1130 may determine that the resources for sending a random access message of a two-step random access procedure to a base station during an association mode period are the same resources for retransmitting the random access message of the two-step random access procedure during the association mode period based on the retransmission counter satisfying a threshold. In some examples, the resource component 1130 may determine that the resources for sending a random access message of a two-step random access procedure to a base station during an association mode period are different from the resources for retransmitting the random access message of the two-step random access procedure during the association mode period based on the retransmission counter satisfying a threshold.

[0232] In some cases, based on UE capabilities, the random access preamble of the two-step random access procedure shares one or more ROs with one or more additional random access preambles of the four-step random access procedure. In some cases, based on the random access procedure fallback capability, the random access preamble of the two-step random access procedure shares one or more ROs with one or more additional random access preambles of the four-step random access procedure. In some cases, based on load balancing capability, the random access preamble of the two-step random access procedure shares one or more ROs with one or more additional random access preambles of the four-step random access procedure. In some cases, based on multiplexing of contention-free random access and contention-based random access, the random access preamble of the two-step random access procedure shares one or more ROs with one or more additional random access preambles of the four-step random access procedure. In some cases, a portion of the random access preamble of the number of SSBs mapped to the two-step random access procedure is one or more of the following: continuous in the time domain or discontinuous in the time domain.

[0233] The threshold component 1135 can determine that the number of SSBs meets the threshold. In some examples, the threshold component 1135 can determine that the number of SSBs is greater than the threshold, wherein the number of SSBs is mapped to the same RO in one or more ROs shared between the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure.

[0234] The sequence component 1140 may determine that the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure are configured to have different preamble sequence subsets. In some examples, the sequence component 1140 may determine that the preamble sequences in each subset of the preamble sequence subsets are non-overlapping. In some cases, the indexes of the preamble sequences in each subset of the preamble sequence subsets are continuous.

[0235] The beam component 1145 can determine that the transmit beams mapped to the random access preamble of the two-step random access process and the random access message of the four-step random access process have the same or different preamble sequence sizes based on the spatial separation of the transmit beams mapped to the random access preamble of the two-step random access process and the random access message of the four-step random access process. In some examples, the beam component 1145 can perform beam switching of one or more additional beams carrying the random access preamble or random access payload of the random access message or both. In some examples, the beam component 1145 can determine a change in the physical random access channel timing index of one or more ROs. In some examples, the beam component 1145 performs beam switching of one or more additional beams carrying the random access preamble or random access payload of the random access message or both based on the change in the physical random access channel timing index.

[0236] In some examples, the beam component 1145 may determine a change in a physical uplink shared channel resource unit index associated with one or more PRUs of a random access payload. In some examples, the beam component 1145 performs beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message based on a change in a physical uplink shared channel resource unit index associated with one or more PRUs of a random access payload. In some examples, the beam component 1145 may determine a change in a preamble sequence index of a random access preamble. In some examples, the beam component 1145 performs beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message based on a change in a random access preamble. In some examples, the beam component 1145 may determine that UCI is to be multiplexed onto one or more of a random access preamble and a random access payload of a random access message.

[0237] In some examples, the beam component 1145 performs beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message based on multiplexing UCI onto one or more of the random access preamble and the random access payload of the random access message. In some examples, the beam component 1145 can perform beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message in conjunction with additional beam switching of one or more beams carrying SSB by the base station.

[0238] In some cases, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure have the same receive beam. In some cases, the number of SSBs has different transmit beams. In some cases, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure have different receive beams. In some cases, beam switching is enabled based on one or more of association, mapping, or trigger indication. In some cases, the trigger indication includes one or more of a preamble sequence, a reference signal, or UCI.

[0239] The fallback component 1150 can perform a random access fallback procedure or a random access switching procedure from a two-step random access procedure to a four-step random access procedure, wherein performing beam switching is based on the random access fallback procedure or the random access switching procedure. In some examples, the fallback component 1150 can identify a random access message of a four-step random access procedure based on the random access fallback procedure or the random access switching procedure, wherein performing beam switching is based on control signaling from a base station, and the beam switching includes switching one or more of a transmit beam and a receive beam. In some examples, the fallback component 1150 can identify a random access message of a four-step random access procedure based on a random access fallback procedure or a random access switching procedure, wherein performing beam switching is based on including associated preconfiguration information. In some cases, the control signaling includes DCI.

[0240] Fig.12A diagram of a system 1200 including a device 1205 supporting beam association in a random access procedure 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 a component of the device 905, the device 1005, or the UE 115. The device 1205 may include components for two-way voice and data communications, including components for sending and receiving communications, including a UE communication manager 1210, an I / O controller 1215, a transceiver 1220, an antenna 1225, a memory 1230, and a processor 1240. These components may communicate electronically via one or more buses (e.g., a bus 1245).

[0241] The UE communication manager 1210 as described herein may be implemented to achieve one or more potential advantages. One implementation may be by communicating with a base station 105 (e.g. Figure 1 1205) can communicate more efficiently to allow the device 1205 to save power and increase battery life. Another implementation can facilitate low-latency communication at the device 1205 because beam association for random access messaging related to different random access procedures can be improved.

[0242] The UE communication manager 1210 may perform the following operations: determine, based on the indication, a mapping between an SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload; determine, based on the mapping, an association between one or more beams carrying an SSB and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and perform a two-step random access procedure with a base station.

[0243] 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 a computer such as a , 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.

[0244] 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 for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from the antenna. In some cases, the device 1205 may include a single antenna 1225. However, in some cases, the device 1205 may have more than one antenna 1225, which may be capable of simultaneously sending or receiving multiple wireless transmissions.

[0245] The memory 1230 may include RAM and ROM. The memory 1230 may store computer-readable, computer-executable code 1235, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1230 may also contain, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0246] 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 (e.g., system memory or other types of memory). In some cases, the code 1235 may not be directly executable by the processor 1240, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0247] 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 association in a random access process).

[0248] Fig.13A block diagram 1300 of a device 1305 supporting beam association in a random access procedure according to aspects of the present disclosure is shown. The device 1305 can be an example of aspects of a base station 105 as described herein. The device 1305 may include a receiver 1310, a base station communication manager 1315, and a transmitter 1320. The device 1305 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0249] The 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 association in a random access process, etc.). The information may be communicated to other components of the device 1305. The receiver 1310 may be a reference Fig.16 Examples of various aspects of the transceiver 1620 are described. The receiver 1310 may utilize a single antenna or a group of antennas.

[0250] The base station communication manager 1315 may perform the following operations: determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload, and the mapping including an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information including one or more of the following items to the UE: a mapping between the SSB and the random access message of the two-step random access procedure, and an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform a two-step random access procedure with the UE according to the mapping. The base station communication manager 1315 may be an example of aspects of the base station communication manager 1610 described herein.

[0251] The base station 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 base station 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, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0252] The base station communication manager 1315 or its subcomponents may be physically located at various locations, including being distributed so that portions of the functions are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the base station communication manager 1315 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the base station 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, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or combinations thereof).

[0253] The transmitter 1320 may transmit signals generated by other components of the device 1305. In some examples, the transmitter 1320 may be co-located with the receiver 1310 in a transceiver module. Fig.16 Examples of various aspects of the transceiver 1620 are described. The transmitter 1320 may utilize a single antenna or a group of antennas.

[0254] Fig.14 A block diagram 1400 of a device 1405 supporting beam association in a random access procedure according to 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 base station communication manager 1415, and a transmitter 1435. The device 1405 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0255] The 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 association in a random access process, etc.). The information may be communicated to other components of the device 1405. The receiver 1410 may be a reference Fig.16 Examples of various aspects of the transceiver 1620 are described. The receiver 1410 may utilize a single antenna or a group of antennas.

[0256] The base station communication manager 1415 can be an example of aspects of the base station communication manager 1315 as described herein. The base station communication manager 1415 can include a mapping component 1420, an information component 1425, and an access component 1430. The base station communication manager 1415 can be an example of aspects of the base station communication manager 1610 described herein.

[0257] The mapping component 1420 may determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message comprising a random access preamble and a random access payload, and the mapping comprising an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The information component 1425 may send information including one or more of the following to the UE: a mapping between the SSB and a random access message of a two-step random access procedure, and an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The access component 1430 may perform a two-step random access procedure with the UE based on the mapping.

[0258] Transmitter 1435 can transmit signals generated by other components of device 1405. In some examples, transmitter 1435 can be co-located with receiver 1410 in a transceiver module. For example, transmitter 1435 can be a reference Fig.16 Examples of various aspects of the transceiver 1620 are described. The transmitter 1435 may utilize a single antenna or a group of antennas.

[0259] Fig.15 A block diagram 1500 of a base station communication manager 1505 supporting beam association in a random access procedure in accordance with aspects of the present disclosure is shown. The base station communication manager 1505 can be an example of aspects of the base station communication manager 1315, the base station communication manager 1415, or the base station communication manager 1610 described herein. The base station communication manager 1505 can include a mapping component 1510, an information component 1515, an access component 1520, a signaling component 1525, a resource component 1530, a threshold component 1535, a sequence component 1540, a beam component 1545, and a backoff component 1550. Each of these modules can communicate with each other directly or indirectly (e.g., via one or more buses).

[0260] The mapping component 1510 may determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message comprising a random access preamble and a random access payload, and the mapping comprises an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. In some examples, the mapping component 1510 may map resources of the SSB to one or more ROs of the random access preamble and one or more PRUs of the random access payload within a PRACH configuration period in an association mode period of the two-step random access procedure.

[0261] The mapping component 1510 may determine a mapping between one or more PRUs of a shared time / frequency resource of a random access payload and an SSB in the SSB or a portion of the SSB in the SSB, wherein the portion of the SSB in the SSB is grouped. In some examples, the mapping component 1510 may map the one or more PRUs of a shared time / frequency resource of a random access payload to the SSB in the SSB based on an analog beamforming capability. In some examples, the mapping component 1510 may map the one or more PRUs of a shared time / frequency resource of a random access payload to the portion of the SSB in the SSB based on a digital beamforming capability. In some cases, based on a guard period associated with a random access preamble and a duration of a gap period between the random access preamble and the random access payload, the random access preamble and the random access payload of the random access message are associated with different SSBs in the SSB.

[0262] The information component 1515 may send information including one or more of the following to the UE: a mapping between the SSB and the random access message of the two-step random access procedure, and an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The access component 1520 may perform the two-step random access procedure with the UE based on the mapping.

[0263] The signaling component 1525 may send signaling including information including one or more of: a mapping between SSBs and random access messages of a two-step random access procedure, and an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message. In some cases, the signaling includes system information signaling. In some cases, the signaling includes RRC signaling.

[0264] The resource component 1530 may determine one or more PRUs of the random access payload to share time / frequency resources. In some cases, the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure are mapped to different SSBs in the plurality of SSBs. In some cases, a portion of the number of SSBs mapped to the random access preamble of the two-step random access procedure is one or more of the following: continuous in the time domain or non-continuous in the time domain.

[0265] The threshold component 1535 can determine that the number of SSBs meets the threshold. In some examples, the threshold component 1535 can determine that the number of SSBs is greater than the threshold, wherein the number of SSBs is mapped to the same RO in one or more ROs shared between the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure.

[0266] The sequence component 1540 can determine that the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure are configured to have different preamble sequence subsets. In some cases, the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure have the same receive beam.

[0267] The beam component 1545 may perform beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message, wherein the one or more additional beams include a receive beam. In some examples, the beam component 1545 may perform beam switching of one or more additional beams carrying a random access preamble or a random access payload or both of a random access message in conjunction with beam switching of one or more beams carrying SSBs, wherein the one or more additional beams include a receive beam and the one or more beams carrying SSBs include a transmit beam. In some cases, the number of SSBs have different transmit beams. In some cases, the random access preamble of a random access message of a two-step random access procedure and the random access message of a four-step random access procedure have different receive beams.

[0268] The fallback component 1550 may perform a random access fallback procedure or a random access switching procedure from a two-step random access procedure to a four-step random access procedure, wherein performing beam switching is based on the random access fallback procedure or the random access switching procedure. In some examples, the fallback component 1550 may identify a random access message of a four-step random access procedure based on the random access fallback procedure or the random access switching procedure. In some examples, the fallback component 1550 may send control signaling to the UE, wherein performing beam switching is based on the control signaling, and the beam switching includes switching one or more of a transmit beam and a receive beam.

[0269] In some cases, the control signaling includes DCI.

[0270] Fig.16A diagram of a system 1600 including a device 1605 supporting beam association in a random access procedure according to various 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 a component of the device 1305, the device 1405, or the base station 105. The device 1605 may include components for two-way voice and data communications, including components for sending and receiving communications, including a base station 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 communicate electronically via one or more buses (e.g., a bus 1650).

[0271] The base station communication manager 1610 can perform the following operations: determine the mapping between the SSB and the random access message of the two-step random access process, the random access message includes a random access preamble and a random access payload, and the mapping includes an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message; send information including one or more of the following items to the UE: the mapping between the SSB and the random access message of the two-step random access process, and the association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and perform the two-step random access process with the UE according to the mapping.

[0272] 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 transmission of data communications for client devices (eg, one or more UEs 115).

[0273] The transceiver 1620 can communicate bidirectionally via one or more antennas, wired or wireless links as described above. For example, the transceiver 1620 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1620 can also include a modem, which is used to modulate packets and provide the modulated packets to the antenna for transmission, and demodulate the packets received from the antenna. In some cases, the device 1605 may include a single antenna 1625. However, in some cases, the device 1605 may have more than one antenna 1625, which can send or receive multiple wireless transmissions simultaneously.

[0274] Memory 1630 may include RAM, ROM, or a combination thereof. Memory 1630 may store computer readable code 1635, which includes 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 also contain, among other things, BIOS, which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0275] 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 (e.g., system memory or other types of memory). In some cases, the code 1635 may not be directly executable by the processor 1640, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0276] 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 association in a random access process).

[0277] The inter-site communication manager 1645 can manage communications with other base stations 105 and can 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 can coordinate the scheduling of transmissions to UE 115 to implement various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-site communication manager 1645 can provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0278] Fig.17 A flow chart illustrating a method 1700 for supporting beam association in a random access procedure according to aspects of the present disclosure is shown. The operations of the method 1700 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1700 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 units 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.

[0279] At 1705, the UE may determine, based on the indication, a mapping between the SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be as described with reference to Figures 9 to 12 The mapping components described are executed.

[0280] At 1710, the UE may determine, based on the mapping, an association between one or more beams carrying the SSB and one or more additional beams carrying a random access preamble and a random access payload of a random access message. 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 Described by the associated components to perform.

[0281] At 1715, the UE may perform a two-step random access procedure with the base station. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be as described with reference to Figures 9 to 12 The described access components are executed.

[0282] Fig.18 A flow chart illustrating a method 1800 for supporting beam association in a random access procedure according to aspects of the present disclosure is shown. 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 units 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.

[0283] At 1805, the UE may determine, based on the indication, a mapping between the SSB and a random access message of a two-step random access procedure, the random access message including a random access preamble and a random access payload. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be as described with reference to Figures 9 to 12 The mapping components described are executed.

[0284] At 1810, the UE may determine, based on the mapping, an association between one or more beams carrying the SSB and one or more additional beams carrying a random access preamble and a random access payload of a random access message. 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 12 Described by the associated components to perform.

[0285] At 1815, the UE may map resources of the SSB to one or more ROs of a random access preamble and one or more PRUs of a random access payload within a PRACH configuration period in an associated mode period of a two-step random access procedure. 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 mapping components described are executed.

[0286] At 1820, the UE may perform a two-step random access procedure with the base station. 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 described access components are executed.

[0287] Fig.19 A flow chart illustrating a method 1900 for supporting beam association in a random access procedure according to aspects of the present disclosure is shown. The operations of the method 1900 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 1900 may be implemented by a 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 units 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.

[0288] At 1905, the base station may determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message comprising a random access preamble and a random access payload, and the mapping comprising an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. 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 13 to 16 The mapping components described are executed.

[0289] At 1910, the base station may send information including one or more of the following to the UE: a mapping between SSBs and random access messages of a two-step random access procedure, and an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message. 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 13 to 16 Describes the information components to perform.

[0290] At 1915, the base station may perform a two-step random access procedure with the UE according to the mapping. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be as described with reference to Figures 13 to 16 The described access components are executed.

[0291] Fig. 20 A flow chart illustrating a method 2000 for supporting beam association in a random access procedure according to aspects of the present disclosure is shown. The operations of the method 2000 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 2000 may be implemented by a 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 units 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.

[0292] At 2005, the base station may determine a mapping between an SSB and a random access message of a two-step random access procedure, the random access message comprising a random access preamble and a random access payload, and the mapping comprising an association between one or more beams carrying the SSB and one or more additional beams carrying the random access preamble and the random access payload of the random access message. 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 13 to 16 The mapping components described are executed.

[0293] At 2010, the base station may send information including one or more of the following to the UE: a mapping between SSBs and random access messages of a two-step random access procedure, and an association between one or more beams carrying SSBs and one or more additional beams carrying a random access preamble and a random access payload of a random access message. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed as described with reference to Figures 13 to 16 Describes the information components to perform.

[0294] At 2015, the base station may map resources of the SSB to one or more ROs of the random access preamble and one or more PRUs of the random access payload within the PRACH configuration period in the association mode period of the two-step random access procedure. 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 13 to 16 The mapping components described are executed.

[0295] At 2020, the base station may perform a two-step random access procedure with the UE according to the mapping. The operations of 2020 may be performed according to the methods described herein. In some examples, various aspects of the operations of 2020 may be described with reference to Figures 13 to 16 The described access components are executed.

[0296] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0297] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may be applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable 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.

[0298] The information and signals described herein may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0299] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, CPU, 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 an alternative, the processor may be any conventional 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, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0300] 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 sent through a computer-readable medium as one or more instructions or codes. Other examples and implementations are 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 in software executed by a processor, hardware, firmware, hard wiring, or any combination of these. Features that implement the functions may also be physically located at various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0301] Computer readable medium includes both non-transitory computer storage medium and communication medium, and communication medium includes any medium that promotes the transmission of computer program from one place to another place.Non-transitory storage medium can be any available medium that can be accessed by general-purpose computer or special-purpose computer.By way of example and not limitation, non-transitory computer readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage device, or can be used for carrying or storing desired program code unit and can be accessed by general-purpose or special-purpose computer or general-purpose or special-purpose processor in the form of instruction or data structure Any other non-transitory medium.In addition, any connection is appropriately referred to as computer readable medium.For example, if software is to send 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 coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of computer readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein 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.

[0302] As used herein (including in the claims), "or" as used in a list of items (e.g., a list of items ending 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). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can 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".

[0303] 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, the second reference number being used to distinguish between similar components. If only the first reference number is used in the specification, the description applies to any of the similar components having the same first reference number, without regard to the second reference number or other subsequent reference numbers.

[0304] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "advantageous over other examples." For the purpose of providing an understanding of the described techniques, the detailed description includes specific details. However, these techniques may be implemented without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0305] To enable those skilled in the art to implement or use the present disclosure, the description herein is provided. It will be apparent to those skilled in the art that various modifications to the present disclosure will be apparent, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment, comprising: receiving, from a network entity, a configuration of a physical random access channel (PRACH) opportunity for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single one of the PRACH opportunities and a number of contention-based preambles for each of the synchronization signal blocks for each valid one of the PRACH opportunities; determining an association between the synchronization signal block and a set of PRACH opportunities based at least in part on the configuration and an associated pattern period of the two-step random access procedure, wherein the associated pattern period is based at least in part on a limited range / time domain configured by the network entity; mapping resources of the synchronization signal block to the set of PRACH opportunities and one or more physical uplink shared channel resource elements within a PRACH configuration period of the associated mode period of the two-step random access procedure based at least in part on the association; and The two-step random access procedure is performed with the network entity based at least in part on the mapping.

2. The method according to claim 1, further comprising: determining a second association between the synchronization signal block and the PRACH opportunity set based at least in part on a second association pattern period of the two-step random access procedure; as well as The resources of the synchronization signal block are mapped to the PRACH opportunity set and the one or more physical uplink shared channel resource units within an additional PRACH configuration period of the second association mode period of the two-step random access procedure.

3. The method according to claim 2, wherein: The second association during the second association pattern period of the two-step random access procedure is different from the association during the association pattern period of the two-step random access procedure.

4. The method according to claim 1, wherein: Receiving the configuration from the network entity further comprises: Signaling including the configuration is received from the network entity, wherein the signaling includes system information signaling, radio resource control signaling, or both.

5. The method according to claim 1, further comprising: The association between the synchronization signal block and the set of PRACH opportunities is determined based at least in part on a PRACH opportunity index of the one or more PRACH opportunities, wherein the configuration includes the PRACH opportunity index.

6. The method according to claim 1, further comprising: The association between the synchronization signal block and the set of PRACH opportunities is determined based at least in part on a preamble sequence of a random access preamble, wherein the configuration includes the preamble sequence.

7. The method according to claim 1, further comprising: The association between the synchronization signal block and the PRACH opportunity set is determined based at least in part on a physical uplink shared channel resource unit index associated with the one or more physical uplink shared channel resource units, wherein the configuration includes the physical uplink shared channel resource unit index.

8. The method according to claim 1, wherein: The set of PRACH opportunities and the one or more physical uplink shared channel resource elements are associated with different ones of the synchronization signal blocks based at least in part on a number of symbols between the set of PRACH opportunities and the one or more physical uplink shared channel resource elements.

9. The method according to claim 8, wherein: The number of symbols between the PRACH opportunity set and the one or more physical uplink shared channel resource elements is configured by the network entity.

10. The method according to claim 1, further comprising: determining that the one or more physical uplink shared channel resource units share one or more of a time resource and a frequency resource; as well as Determine a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources and a synchronization signal block in the synchronization signal block or a portion of the synchronization signal blocks in the synchronization signal block, wherein the portion of the synchronization signal blocks in the synchronization signal block is grouped.

11. The method according to claim 10, wherein: Determining the mapping between the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources and the one of the synchronization signal blocks or the portion of the synchronization signal blocks includes: The one or more physical uplink shared channel resource elements that share one or more of the time resources and the frequency resources are mapped to the one of the synchronization signal blocks based at least in part on analog beamforming capabilities.

12. The method according to claim 10, wherein: Determining the mapping between the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources and the one of the synchronization signal blocks or the portion of the synchronization signal blocks includes: The one or more physical uplink shared channel resource elements sharing one or more of the time resources and the frequency resources are mapped to the portion of the synchronization signal blocks in the synchronization signal blocks based at least in part on digital beamforming capabilities.

13. The method according to claim 1, further comprising: The one or more PRACH opportunities of the two-step random access procedure are determined to be shared with the four-step random access procedure based at least in part on UE capabilities, random access procedure fallback capabilities, load balancing capabilities, or multiplexing of contention-free random access and contention-based random access, or any combination thereof.

14. The method according to claim 1, further comprising: Determining that the number of synchronization signal blocks meets a threshold; as well as It is determined that the random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure are configured to have different preamble sequence subsets.

15. The method according to claim 14, wherein: The indexes of the preamble sequences in each subset of the preamble sequence subsets are continuous.

16. The method according to claim 14, wherein: The preamble sequences in each subset of the preamble sequence subsets are non-overlapping.

17. The method according to claim 1, further comprising: Determine that the number of synchronization signal blocks is greater than a threshold, wherein the number of synchronization signal blocks is mapped to the same PRACH opportunity among the one or more PRACH opportunities shared between the random access preamble code of the two-step random access process and the random access message of the four-step random access process.

18. The method according to claim 17, wherein: The number of synchronization signal blocks have different transmit beams.

19. The method according to claim 17, wherein: The random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure are mapped to different synchronization signal blocks among the number of synchronization signal blocks.

20. The method according to claim 19, wherein: A portion of the synchronization signal blocks among the number of synchronization signal blocks mapped to the random access preamble code of the two-step random access procedure is one or more of the following: continuous in the time domain, or discontinuous in the time domain.

21. The method according to claim 19, wherein: At least partially based on the spatial separation of the transmit beams of the random access preamble mapped to the two-step random access procedure and the random access message of the four-step random access procedure, the transmit beams of the random access preamble mapped to the two-step random access procedure and the random access message of the four-step random access procedure have the same or different preamble sequence sizes.

22. The method according to claim 19, wherein: The random access preamble of the random access message of the two-step random access procedure and the random access message of the four-step random access procedure have different reception beams.

23. A method for wireless communication at a network entity, comprising: outputting a configuration of a physical random access channel (PRACH) opportunity for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single one of the PRACH opportunities and a number of contention-based preambles for each of the synchronization signal blocks for each valid one of the PRACH opportunities; determining an association between the synchronization signal block and a set of PRACH opportunities based at least in part on the configuration and an associated pattern period of the two-step random access procedure, wherein the associated pattern period is based at least in part on a limited range / time domain configured by the network entity; mapping resources of the synchronization signal block to the set of PRACH opportunities and one or more physical uplink shared channel resource elements within a PRACH configuration period of the associated mode period of the two-step random access procedure based at least in part on the association; and The two-step random access procedure is performed with a user equipment based at least in part on the mapping.

24. The method according to claim 23, wherein: Output of the configuration includes: Output signaling, the signaling comprising the configuration indicating the number of synchronization signal blocks associated with the single PRACH opportunity in the PRACH opportunities and the number of contention-based preambles for each of the synchronization signal blocks for each valid PRACH opportunity in the PRACH opportunities, wherein the signaling comprises system information signaling, or radio resource control signaling, or both.

25. The method according to claim 23, wherein: The set of PRACH opportunities and the one or more physical uplink shared channel resource elements are associated with different ones of the synchronization signal blocks based at least in part on a number of symbols between the set of PRACH opportunities and the one or more physical uplink shared channel resource elements.

26. The method of claim 23, further comprising: determining that the one or more physical uplink shared channel resource units share one or more of a time resource and a frequency resource; as well as Determine a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources and a synchronization signal block in the synchronization signal block or a portion of the synchronization signal blocks in the synchronization signal block, wherein the portion of the synchronization signal blocks in the synchronization signal block is grouped.

27. The method according to claim 26, wherein: Determining the mapping between the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources and the one of the synchronization signal blocks or the portion of the synchronization signal blocks includes: The one or more physical uplink shared channel resource elements that share one or more of the time resources and the frequency resources are mapped to the one of the synchronization signal blocks based at least in part on analog beamforming capabilities.

28. An apparatus for wireless communication, comprising: one or more processors, one or more memories coupled to the one or more processors; as well as Instructions, which are stored in the one or more memories and can be executed by the one or more processors individually or collectively to cause the device to perform the following operations: receiving, from a network entity, a configuration of a physical random access channel (PRACH) opportunity for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single one of the PRACH opportunities and a number of contention-based preambles for each of the synchronization signal blocks for each valid one of the PRACH opportunities; determining an association between the synchronization signal block and a set of PRACH opportunities based at least in part on the configuration and an associated pattern period of the two-step random access procedure, wherein the associated pattern period is based at least in part on a limited range / time domain configured by the network entity; mapping resources of the synchronization signal block to the set of PRACH opportunities and one or more physical uplink shared channel resource elements within a PRACH configuration period of the associated mode period of the two-step random access procedure based at least in part on the association; and The two-step random access procedure is performed with the network entity based at least in part on the mapping.

29. The device according to claim 28, wherein The instructions may also be executed by the one or more processors individually or collectively to cause the device to perform the following operations: determining a second association between the synchronization signal block and the PRACH opportunity set based at least in part on a second association pattern period of the two-step random access procedure; as well as The resources of the synchronization signal block are mapped to the PRACH opportunity set and the one or more physical uplink shared channel resource units within an additional PRACH configuration period of the second association mode period of the two-step random access procedure.

30. An apparatus for wireless communication, comprising: one or more processors, one or more memories coupled to the one or more processors; as well as Instructions, which are stored in the one or more memories and can be executed by the one or more processors individually or collectively to cause the device to perform the following operations: outputting a configuration of a physical random access channel (PRACH) opportunity for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single one of the PRACH opportunities and a number of contention-based preambles for each of the synchronization signal blocks for each valid one of the PRACH opportunities; determining an association between the synchronization signal block and a PRACH opportunity set based at least in part on the configuration and an associated pattern period of the two-step random access procedure, wherein the associated pattern period is based at least in part on a limited range / time domain configured by a network entity; mapping resources of the synchronization signal block to the set of PRACH opportunities and one or more physical uplink shared channel resource elements within a PRACH configuration period of the associated mode period of the two-step random access procedure based at least in part on the association; and The two-step random access procedure is performed with a user equipment based at least in part on the mapping.

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