Beam correlation in random access procedures.

Abstract

To provide methods and devices for improving robustness for beam association and extended random access (RA) messaging in wireless communication.SOLUTION: In a wireless communication system, a user equipment (UE) 115-c receives a configuration of physical RA channel (PRACH) opportunities for a two-step RA procedure (the configuration indicates multiple synchronization signal blocks (SSBs) associated with a single PRACH opportunity and a contention-based preamble for each of the SSBs), determines an association between the SSBs and a set of PRACH opportunities based on the configuration and a finite range / time domain-based association pattern period configured by a network entity, maps resources of the SSBs to physical uplink shared channel (PUSCH) resource units and the set of PRACH opportunities based on the association, and performs the two-step RA procedure based on the mapping.SELECTED DRAWING: Figure 8

Description

cross reference

[0001]

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 856,683, filed June 3, 2019, entitled "Beam Correlation in Random Access Procedures," and U.S. Patent Application No. 16 / 887,970, filed May 29, 2020, entitled "Beam Correlation in Random Access Procedures," to LEI et al., each of which is assigned to the assignee of the present application. [Technical Field]

[0002]

[0002] The following relates generally to wireless communications, and more particularly to beam association in random access procedures.

[0003]

[0003] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcasts, and so on. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth-generation (4G) systems, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), or LTE-A Pro systems, and fifth-generation (5G) systems, sometimes referred to as new radio (NR) systems. These systems may use technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiple access (DFT-S-OFDM).

[0004]

[0004] A wireless multiple-access communication system may include several base stations or network access nodes, each of which simultaneously supports communication for multiple communication devices, which may otherwise be known as user equipment (UE). Some wireless communication systems may support one or more random access procedures. A random access procedure may involve a series of handshake messages exchanged between a UE and a base station. As demands for wireless communication system efficiency increase, some wireless communication systems may not be able to provide robustness for beam association and extended random access messaging, and therefore improved techniques are desired.

[0005]

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses that support beam association in random access procedures. Generally, the described techniques result in a user equipment (UE) determining a mapping between multiple synchronization signal blocks (SSBs) and a random access message, e.g., associated with a two-step random access procedure. The UE may also determine an association between one or more respective directional beams carrying the multiple SSBs and one or more additional respective directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message).

[0006]

[0006] Further, the described techniques may, in some examples, include mapping time and frequency resources of multiple SSBs to one or more Physical Random Access Channel (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 over a PRACH configuration period of an association pattern period of a two-step random access procedure. Additionally or alternatively, the described techniques may include beam association for random access fallback procedures and random access switch procedures. Thus, the described techniques may include features for improved resource utilization and allocation for random access messaging and features for improved reliability for random access messaging, and may, in some examples, facilitate low latency for random access procedures, among other benefits.

[0007]

[0007] A method of wireless communication in a user equipment is described. The method may include determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0008]

[0008] An apparatus for wireless communication in 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 determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0009]

[0009] Another apparatus for wireless communications in a user equipment is described. The apparatus may include means for determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0010]

[0010] A non-transitory computer-readable medium storing code for wireless communication in a user equipment is described, wherein the code may include instructions executable by a processor to: determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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 the base station.

[0011]

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for mapping resources of a plurality of synchronization signal blocks 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 over a physical random access channel configuration period of an association pattern period of a two-step random access procedure.

[0012]

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining, based on the second indication, an association pattern duration for a two-step random access procedure, where the association pattern duration for the two-step random access procedure may be based on a factor value of the association pattern duration for the four-step random access procedure, where the factor value comprises an integer value within a range configured by the network.

[0013]

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a second association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message over an additional physical random access channel configuration period of a second association pattern period of the two-step random access procedure, where the second association over the second association pattern period of the two-step random access procedure may be different from the association over the association pattern period of the two-step random access procedure.

[0014]

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for receiving signaling from a base station including an indication including an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message, the signaling including system information signaling or radio resource control signaling, or both.

[0015]

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message based on a physical random access channel opportunity index of one or more physical random access channel opportunities, wherein the indication includes the physical random access channel opportunity index.

[0016]

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining an association between one or more beams carrying multiple synchronization signal blocks and one or more additional beams carrying the random access preamble and random access payload of the random access message based on a preamble sequence of the random access preamble, wherein the indication includes the preamble sequence.

[0017]

[0017] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message based on a physical uplink shared channel resource unit index related to 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.

[0018]

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of the random access message based on multiplexing uplink control information in 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.

[0019]

[0019] 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 synchronization signal blocks of a plurality of synchronization signal blocks based on the duration of a guard period associated with the access preamble and the gap duration between the random access preamble and the random access payload.

[0020]

[0020] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that one or more physical uplink shared channel resource units of the random access payload share one or more of a time resource and a frequency resource, and for determining a mapping between one or more physical uplink shared channel resource units of the random access payload that share one or more of a time resource and a frequency resource and a synchronization signal block of a plurality of synchronization signal blocks or a portion of a synchronization signal block of a plurality of synchronization signal blocks, where the portion of the synchronization signal blocks of the plurality of synchronization signal blocks may be grouped.

[0021]

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between one or more physical uplink shared channel resource units of a random access payload that shares one or more of a time resource and a frequency resource and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks may further include operations, features, means, or instructions for mapping one or more physical uplink shared channel resource units of a random access payload that shares one or more of a time resource and a frequency resource to a synchronization signal block of the plurality of synchronization signal blocks based on analog beamforming capabilities.

[0022]

[0022] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between one or more physical uplink shared channel resource units of a random access payload that share one or more of time and frequency resources and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks may further include operations, features, means, or instructions for mapping one or more physical uplink shared channel resource units of a random access payload that share one or more of time and frequency resources to a synchronization signal block of the plurality of synchronization signal blocks based on digital beamforming capabilities.

[0023]

[0023] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that one or more physical random access channel opportunities of a random access preamble may be shared with one or more additional random access preambles of a four-step random access procedure based on UE capabilities, random access procedure fallback capabilities, load balancing capabilities, or multiplexing of connection-free random access and contention-based random access, or any combination thereof.

[0024]

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that the number of synchronization signal blocks meets a threshold, and for determining that 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 may be composed of different subsets of preamble sequences.

[0025]

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indices of the preamble sequences in each subset of the subsets of preamble sequences may be consecutive.

[0026]

[0026] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for allowing the preamble sequences in each subset of the subsets of preamble sequences to be non-overlapping.

[0027]

[0027] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, 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 may have the same receive beam.

[0028]

[0028] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that a number of synchronization signal blocks may be greater than a threshold, and some synchronization signal blocks may be mapped to the same physical random access channel opportunity of one or more physical random access channel opportunities shared between a random access preamble of a two-step random access procedure and a random access message of a four-step random access procedure.

[0029]

[0029] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, some synchronization signal blocks may have different transmit beams.

[0030]

[0030] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of a two-step random access procedure and the random access message of a four-step random access procedure may be mapped to different synchronization signal blocks of several synchronization signal blocks.

[0031]

[0031] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, some of the synchronization signal blocks mapped to the random access preamble of the two-step random access procedure may be one or more of contiguous in the time domain, or non-contiguous in the time domain.

[0032]

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting beams mapped to a random access preamble of a two-step random access procedure and a random access message of a four-step random access procedure may 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 procedure and the random access message of the four-step random access procedure.

[0033]

[0033] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, 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 may have different receive beams.

[0034]

[0034] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, performing the two-step random access procedure may further include operations, features, means, or instructions for transmitting a random access message of the two-step random access procedure to the base station during an association pattern period, and for retransmitting the random access message of the two-step random access procedure during the association pattern period based on the retransmission counter being less than a threshold.

[0035]

[0035] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing a beam switch of one or more additional beams carrying a random access preamble or a random access payload, or both, of a random access message.

[0036]

[0036] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a change in a physical random access channel opportunity index of one or more physical random access channel opportunities, and performing a beam switch of one or more additional beams carrying a random access preamble or a random access payload, or both, of a random access message may be based at least in part on the change in the physical random access channel opportunity index.

[0037]

[0037] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a change in a physical uplink shared channel resource unit index associated with one or more physical uplink shared channel resource units of the random access payload, and performing a beam switch of one or more additional beams carrying the random access preamble or the random access payload of the random access message, or both, may 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.

[0038]

[0038] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining a change in a preamble sequence index of a random access preamble, and performing a beam switch of one or more additional beams carrying the random access preamble or the random access payload, or both, of a random access message may be based on the change in the random access preamble.

[0039]

[0039] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining to multiplex uplink control information in one or more of the random access preamble and the random access payload of the random access message, and performing a beam switch of 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 in one or more of the random access preamble and the random access payload of the random access message.

[0040]

[0040] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing a beam switch by a base station of one or more additional beams carrying a random access preamble or a random access payload, or both, of a random access message, along with an additional beam switch by the base station of one or more beams carrying multiple synchronization signal blocks.

[0041]

[0041] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the beam switch may be enabled based on one or more of the correlation, mapping, and / or trigger indication including one or more of a preamble sequence, a reference signal, or uplink control information.

[0042]

[0042] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing a random access fallback procedure or a random access switch procedure from a two-step random access procedure to a four-step random access procedure, and performing a beam switch may be based on the random access fallback procedure or the random access switch procedure.

[0043]

[0043] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for identifying a random access message of a four-step random access procedure based on a random access fallback procedure or a random access switch procedure, and performing the beam switch may be based on control signaling including downlink control information from a base station, and the beam switch includes switching one or more of the transmit beam and the receive beam.

[0044]

[0044] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for identifying a random access message of a four-step random access procedure based on a random access fallback procedure or a random access switch procedure, and performing a beam switch may be based on pre-configuration information including the association.

[0045]

[0045] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a random access message of a two-step random access procedure to a base station during an association pattern period to be the same resources as retransmitting the random access message of a two-step random access procedure during the association pattern period based on the retransmission counter satisfying a threshold.

[0046]

[0046] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a random access message of a two-step random access procedure during an association pattern period from a resource that may be different from a resource that retransmits a random access message of a two-step random access procedure during an association pattern period based on a retransmission counter satisfying a threshold.

[0047]

[0047] A method of wireless communication in a base station is described. The method may include determining a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message, transmitting information to a user equipment including one or more of: the mapping between the plurality of synchronization signal blocks of the two-step random access procedure and the random access message, and the association between the one or more beams carrying the plurality of synchronization signal blocks 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 the user equipment in accordance with the mapping.

[0048]

[0048] An apparatus for wireless communication in 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 determine a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; to transmit information to a user equipment including one or more of the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; and to perform the two-step random access procedure with the user equipment according to the mapping.

[0049]

[0049] Another apparatus for wireless communications in a base station is described. The apparatus may include: means for determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; means for transmitting information to a user equipment, the information including one or more of the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 the user equipment in accordance with the mapping.

[0050]

[0050] A non-transitory computer-readable medium storing code for wireless communications in a base station is described, the code may include instructions executable by a processor to: determine a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; transmit information to a user equipment including one or more of: the mapping between the plurality of synchronization signal blocks of the two-step random access procedure and the random access message and an association between the one or more beams carrying the plurality of synchronization signal blocks 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 the user equipment according to the mapping.

[0051]

[0051] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for mapping resources of a plurality of synchronization signal blocks 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 over a physical random access channel configuration period of an association pattern period of a two-step random access procedure.

[0052]

[0052] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, transmitting information to the user equipment may further include operations, features, means, or instructions for including transmitting signaling including information including one or more of: a mapping between a plurality of synchronization signal blocks and a random access message of a two-step random access procedure; and an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message, wherein the signal includes system information signaling or radio resource control signaling, or both.

[0053]

[0053] 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 synchronization signal blocks of a plurality of synchronization signal blocks based on the duration of a guard period associated with the random access preamble and the gap duration between the random access preamble and the random access payload.

[0054]

[0054] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that one or more physical uplink shared channel resource units of the random access payload share one or more of a time resource and a frequency resource, and for determining a mapping between one or more physical uplink shared channel resource units of the random access payload that share one or more of a time resource and a frequency resource and a synchronization signal block of a plurality of synchronization signal blocks or a portion of a synchronization signal block of a plurality of synchronization signal blocks, where the portion of the synchronization signal blocks of the plurality of synchronization signal blocks may be grouped.

[0055]

[0055] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between one or more physical uplink shared channel resource units of a random access payload that shares one or more of a time resource and a frequency resource and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks may further include operations, features, means, or instructions for mapping one or more physical uplink shared channel resource units of a random access payload that shares one or more of a time resource and a frequency resource to a synchronization signal block of the plurality of synchronization signal blocks based on analog beamforming capabilities.

[0056]

[0056] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining the mapping between one or more physical uplink shared channel resource units of a random access payload sharing a time resource and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks may further include operations, features, means, or instructions for mapping one or more physical uplink shared channel resource units of the random access payload sharing a time resource to a portion of a synchronization signal block of the plurality of synchronization signal blocks based on digital beamforming capabilities.

[0057]

[0057] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that the number of synchronization signal blocks meets a threshold, and for determining that 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 may have the same receive beam but may be composed of different subsets of the preamble sequence.

[0058]

[0058] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for determining that the number of synchronization signal blocks may be greater than a threshold, and some synchronization signal blocks may be mapped to the same physical random access channel opportunity of one or more physical random access channel opportunities shared between a random access preamble of a two-step random access procedure and a random access message of a four-step random access procedure.

[0059]

[0059] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, some synchronization signal blocks may have different transmit beams.

[0060]

[0060] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the random access preamble of a two-step random access procedure and the random access message of a four-step random access procedure may be mapped to different synchronization signal blocks of several synchronization signal blocks.

[0061]

[0061] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, some of the synchronization signal blocks mapped to the random access preamble of the two-step random access procedure may be one or more of contiguous in the time domain, or non-contiguous in the time domain.

[0062]

[0062] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, 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 may have different receive beams.

[0063]

[0063] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing a beam switch 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.

[0064]

[0064] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing beam switching of one or more beams carrying a random access preamble or a random access payload of a random access message, or both, along with beam switching of one or more beams carrying a plurality of synchronization signal blocks, wherein the one or more additional beams include a receive beam, and the one or more beams carrying the plurality of synchronization signal blocks include a transmit beam.

[0065]

[0065] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for performing a random access fallback procedure or a random access switch procedure from a two-step random access procedure to a four-step random access procedure, and performing a beam switch may be based on the random access fallback procedure or the random access switch procedure.

[0066]

[0066] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for identifying a random access message of a four-step random access procedure based on a random access fallback procedure or a random access switch procedure, and for sending control signaling including downlink control information to the user equipment, wherein performing the beam switch may be based on the control signaling, and the beam switch includes switching one or more of the transmit beam and the receive beam.

[0067]

[0067] A method of wireless communication is described that may include a processor, a memory coupled to the processor, and instructions stored in the memory, the instructions executable by the processor to cause an apparatus to determine, based on the mapping, an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message, and to perform a two-step random access procedure with a base station.

[0068]

[0068] An apparatus for wireless communications 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 memory being coupled to the processor and the instructions being stored in the memory, the instructions being executable by the processor to cause the apparatus to determine, based on the mapping, an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message and to perform a two-step random access procedure with a base station.

[0069]

[0069] Another apparatus for wireless communications is described, the apparatus may include a processor, a memory coupled to the processor, means for determining, based on a mapping for instructions stored in the memory and executable by the processor to cause the apparatus to execute, an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message, and means for performing a two-step random access procedure with a base station.

[0070]

[0070] A non-transitory computer-readable medium storing code for wireless communications is described, the code may include instructions executable by a processor, a memory coupled to the processor, the instructions stored in the memory, the instructions executable by the processor to cause an apparatus to determine, based on the mapping, an association between one or more beams carrying a plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of a random access message, and to perform a two-step random access procedure with a base station.

[0071]

[0071] A method of wireless communication is described, the method including a processor, a memory coupled to the processor, and instructions stored in the memory, the instructions executable by the processor to cause an apparatus to transmit, to a user equipment, information including one or more of: a mapping between a plurality of synchronization signal blocks and a random access message of a two-step random access procedure; and an association between one or more beams carrying the plurality of synchronization signal blocks 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 the user equipment in accordance with the mapping.

[0072]

[0072] An apparatus for wireless communications 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 memory being coupled to the processor and the instructions being stored in the memory, the instructions being executable by the processor to cause the apparatus to transmit, to a user equipment, information including one or more of: a mapping between a plurality of synchronization signal blocks and a random access message of a two-step random access procedure; and an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and to perform a two-step random access procedure with the user equipment according to the mapping.

[0073]

[0073] Another apparatus for wireless communications is described, the apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory and executable by the processor to cause the apparatus to execute: means for transmitting information to a user equipment, the information including one or more of: a mapping between a plurality of synchronization signal blocks and a random access message of a two-step random access procedure; and an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and means for performing the two-step random access procedure with the user equipment in accordance with the mapping.

[0074]

[0074] A non-transitory computer-readable medium storing code for wireless communications is described, wherein the code may include instructions executable by a processor, a memory coupled to the processor, the instructions stored in the memory, and the instructions executable by the processor to cause an apparatus to transmit, to a user equipment, information including one or more of: a mapping between a plurality of synchronization signal blocks and a random access message of a two-step random access procedure; and an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying a random access preamble and a random access payload of the random access message; and to perform a two-step random access procedure with the user equipment according to the mapping.

[0075]

[0075] A method of wireless communication is described that may include means for determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0076]

[0076] An apparatus for wireless communications 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: determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0077]

[0077] Another apparatus for wireless communications is described. The apparatus may include means for determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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]

[0078] A non-transitory computer-readable medium having stored thereon code for wireless communications is described. The code may include instructions executable by a processor to: determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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 the base station.

[0079]

[0079] A method of wireless communication is described that may include means for determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message, means for transmitting information to a user equipment including one or more of: the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 the user equipment according to the mapping.

[0080]

[0080] An apparatus for wireless communications 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: determine a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; transmit information to a user equipment, the information including one or more of the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 user equipment according to the mapping.

[0081]

[0081] Another apparatus for wireless communications is described. The apparatus may include means for determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message, means for transmitting information to a user equipment, the information including one or more of the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 the user equipment in accordance with the mapping.

[0082]

[0082] A non-transitory computer-readable medium having stored thereon code for wireless communications is described, the code may include instructions executable by a processor to cause: means for determining a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; means for transmitting, to a user equipment, information including one or more of: the mapping between the plurality of synchronization signal blocks of the two-step random access procedure and the random access message; and means for performing the two-step random access procedure with the user equipment according to the mapping.

[0083]

[0083] A method of wireless communication in a user equipment is described, the code comprising instructions executable by a processor. The method may include determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0084]

[0084] An apparatus for wireless communication in 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 determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0085]

[0085] Another apparatus for wireless communication in a user equipment is described, the code including instructions executable by a processor. The apparatus may include means for determining, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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.

[0086]

[0086] A non-transitory computer-readable medium having stored thereon code for wireless communications in a user equipment, the code including instructions executable by a processor, is described. The code may include instructions executable by the processor to: determine, based on the indication, a mapping between a plurality of synchronization signal blocks 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 plurality of synchronization signal blocks 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 the base station.

[0087]

[0087]

[0013] A method of wireless communication in a base station is described, the code comprising instructions executable by a processor. The method may include: determining a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message comprising a random access preamble and a random access payload, the mapping comprising an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; transmitting information to a user equipment, the information comprising one or more of the mapping between the plurality of synchronization signal blocks of the two-step random access procedure and the random access message and the association between the one or more beams carrying the plurality of synchronization signal blocks 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 the user equipment according to the mapping.

[0088]

[0088] An apparatus for wireless communication in a base station 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 determine a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; to transmit information to a user equipment including one or more of the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; and to perform the two-step random access procedure with the user equipment according to the mapping.

[0089]

[0089] Another apparatus for wireless communication in a base station is described, the code comprising instructions executable by a processor. The apparatus may include: means for determining a mapping between a plurality of synchronization signal blocks 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 mapping comprising an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; means for transmitting, to a user equipment, information comprising one or more of: the mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure and the association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 the user equipment according to the mapping.

[0090]

[0090] A non-transitory computer-readable medium having stored thereon code for wireless communications in a base station, the code including instructions executable by a processor, may include instructions executable by the processor to: determine a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; transmit to a user equipment information including one or more of: the mapping between the plurality of synchronization signal blocks of the two-step random access procedure and the random access message and an association between the one or more beams carrying the plurality of synchronization signal blocks 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 the user equipment according to the mapping. [Brief explanation of the drawings]

[0091] [Figure 1]

[0091] Figure 1 illustrates an example of a system for wireless communication supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 2]

[0092] FIG. 2 illustrates an example of a wireless communication system supporting a four-step random access procedure, according to an aspect of the present disclosure. [Figure 3]

[0093] FIG. 3 illustrates an example of a mapping configuration that supports mapping between one or more physical random access channel (PRACH) configuration periods and association pattern periods, according to an aspect of the present disclosure. [Figure 4]

[0094] FIG. 4 illustrates an example of a wireless communication system supporting a two-step random access procedure, according to an aspect of the present disclosure. [Figure 5]

[0095] FIG. 5 illustrates an example of a transmission chain supporting a two-step random access procedure in accordance with various aspects of the present disclosure. [Figure 6A]

[0096] FIG. 6A illustrates an example of a channel structure that supports beam association in a random access procedure, according to an aspect of the present disclosure. [Figure 6B]

[0097] FIG. 6B illustrates an example mapping configuration that supports inter-beam correlation in a random access procedure, according to an aspect of the present disclosure. [Figure 7A]

[0098] FIG. 7A illustrates an example mapping configuration that supports beam association in a random access procedure, according to an aspect of the present disclosure. [Figure 7B]

[0099] FIG. 7B illustrates an example mapping configuration that supports inter-beam correlation in a random access procedure, according to an aspect of the present disclosure. [Figure 8]

[0100] FIG. 8 illustrates an example process flow for supporting beam association in a random access procedure, according to an embodiment of the present disclosure. [Figure 9]

[0101] FIG. 9 illustrates a block diagram of a device supporting beam association in a random access procedure according to an embodiment of the present disclosure. [Figure 10] FIG. 10 illustrates a block diagram of a device supporting beam association in a random access procedure in accordance with an embodiment of the present disclosure. [Figure 11]

[0102] FIG. 11 illustrates a block diagram of a UE communications manager supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 12]

[0103] FIG. 12 illustrates a diagram of a system including a device that supports beam association in a random access procedure, according to an embodiment of the present disclosure. [Figure 13]

[0104] FIG. 13 illustrates a block diagram of a device supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 14] FIG. 14 illustrates a block diagram of a device supporting beam association in a random access procedure according to an embodiment of the present disclosure. [Figure 15]

[0105] FIG. 15 illustrates a block diagram of a base station communications manager supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 16]

[0106] FIG. 16 illustrates a diagram of a system including a device supporting beam association in a random access procedure in accordance with an embodiment of the present disclosure. [Figure 17]

[0107] FIG. 17 shows a flowchart illustrating a method for supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 18] FIG. 18 shows a flowchart illustrating a method for supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 19] FIG. 19 shows a flowchart illustrating a method for supporting beam association in a random access procedure according to an aspect of the present disclosure. [Figure 20] FIG. 20 shows a flowchart illustrating a method for supporting beam association in a random access procedure according to an aspect of the present disclosure. Detailed Description

[0092]

[0108] Some wireless communication systems may have user equipment (UE) and base stations (e.g., eNodeB (eNB), Next Generation NodeB, or GigaNodeB (all sometimes referred to as gNB)) that establish a connection using a random access procedure. The random access procedure may include a series of handshake messages that convey 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, which may reduce latency compared to other random access procedures that use a greater number of handshake messages, such as a four-step random access procedure. Furthermore, if the two-step random access procedure is unsuccessful or under some other conditions (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 base stations and UEs 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 to provide the UE with 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 to enable beam association, as described herein.

[0093]

[0109] The UE may be configured to determine a mapping between multiple synchronization signal blocks (SSBs) and a random access message, for example, associated with a two-step random access procedure. The UE may also determine an association between one or more respective directional beams carrying the multiple SSBs and one or more additional respective directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message). In addition, the described techniques may, in some examples, include mapping time and frequency resources of the multiple SSBs to one or more Physical Random Access Channel (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 over a Physical Random Access Channel (PRACH) PRACH configuration period of an association pattern period of the two-step random access procedure. Additionally or alternatively, the described techniques may include beam association for random access fallback procedures and random access switch procedures.

[0094]

[0110] Particular aspects of the subject matter described herein may be implemented to realize one or more advantages. The described techniques may support improved power conservation, among other advantages. Accordingly, the supported techniques may include improved UE operation and, in some examples, may promote UE efficiency, among other benefits. Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are then illustrated by and described with reference to mapping configurations, transmit chains, channel structures, and process flows related to beam association in a random access procedure. Aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts related to beam association in a random access procedure.

[0095]

[0111] 1 illustrates an example of a wireless communication system 100 supporting beam association in a random access procedure in accordance with an aspect of the present disclosure. 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 LTE Advanced (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, communications with low-cost and low-complexity devices, or some combination thereof.

[0096]

[0112] The base stations 105 may be dispersed throughout a geographic area and may be devices of different types or with different capabilities to form the wireless communication system 100. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 support communication of signals via one or more radio access technologies.

[0097]

[0113] The 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. The UEs 115 may be devices of different forms or with different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in FIG. 1.

[0098]

[0114] The base stations 105 may communicate with the core network 130, with each other, or both. For example, the base stations 105 may interface with the core network 130 through backhaul links 120 (e.g., via an S1, N2, N3, or other interface). The base stations 105 may communicate with each other via the backhaul links 120 (e.g., via an X2, Xn, or other interface), either directly (e.g., directly between the base stations 105), indirectly (e.g., via the core network 130), or both. In some examples, the backhaul links 120 may be or include one or more wireless links. One or more of the base stations 105 described herein may include or be referred to by those skilled in the art as a base transceiver station, radio base station, access point, radio transceiver, Node B, eNode B (eNB), Next Generation Node B or Giga Node B (any of which may be referred to as gNB), Home Node B, Home eNode B, or other suitable terminology.

[0099]

[0115] The UE 115 may also include or be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or any other suitable terminology, and a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. The UE 115 may also include or 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, the 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 communications (MTC) device, or the like, which may be embodied in various objects, such as appliances, vehicles, meters, or the like. The UEs 115 described herein may be able to communicate with various types of devices, such as base stations 105 and network equipment, including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, and the like, along with other UEs 115, sometimes acting as relays, as shown in FIG. 1.

[0100]

[0116] The UE 115 and the base station 105 may communicate wirelessly with each other over one or more carriers via one or more communication links 125. 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, the carrier used for the communication link 125 may include a portion (e.g., a bandwidth portion (BWP)) of a radio frequency spectrum band operating in accordance with a physical layer channel for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating operation for 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. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers in accordance with a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0101]

[0117] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operation for 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 positioned according to a channel raster for discovery by the UE 115. A carrier may operate in a standalone mode, where initial acquisition and connection may be made by the UE 115 over the carrier, or a carrier may operate in a non-standalone mode, where connection is fixed using a different carrier (e.g., of the same or different radio access technology).

[0102]

[0118] The communication link 125 shown in the wireless communication system 100 may include uplink transmissions from the UE 115 to the base station 105 or downlink transmissions from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode). A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one of several predetermined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)) for a particular radio access technology carrier. A device of the wireless communication system 100 (e.g., a base station 105, a UE 115, or both) may have a hardware configuration that supports communication over a particular carrier bandwidth or may be configurable to support communication over one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication over carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate over a portion (e.g., a sub-band, BWP) of the carrier bandwidth or over all of the carrier bandwidth.

[0103]

[0119] A signal waveform transmitted on a carrier may be composed of multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system using MCM techniques, a resource element may consist of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, where the symbol period and the subcarrier spacing are inversely proportional. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements and the higher the order of the modulation scheme received by the UE 115, the higher the data rate for the UE 115 may 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 communications with the UE 115.

[0104]

[0120] One or more numerologies for a carrier may be supported, and a 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 may be active at a given time, and communication for the UE 115 may be limited to the active BWP. The time interval for a base station 105 or a UE 115 may be, for example, T s =1 / (Δf max N f ) seconds or may be expressed in multiples of the base time unit. max may represent the maximum supported subcarrier spacing, and N fmay represent the maximum supported discrete Fourier transform (DFT) size. The communication resource time intervals 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., in the range of 0 to 1023).

[0105]

[0121] Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some cases, a frame may be divided into subframes, and each subframe may be further divided into several slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on the subcarrier spacing. Each slot may include several symbol periods (e.g., depending on the length of a cyclic prefix prepended to each symbol period). In some wireless communication systems 100, a slot may be further divided into multiple minislots, each containing one or more symbols. Excluding the cyclic prefix, each symbol period may include one or more (e.g., N f ) sampling period. The duration of the symbol period may depend on the subcarrier spacing or frequency band of operation.

[0106]

[0122] A subframe, slot, minislot, or 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 bursts of shortened TTIs (sTTIs)).

[0107]

[0123] Physical channels may be multiplexed onto carriers according to various techniques. Physical control channels and physical data channels may be multiplexed onto downlink carriers using, for example, time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by several symbol periods and may extend across the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in 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 encoded information for a control information format having a given payload size. The search space sets may include a common search space set configured for sending control information to multiple UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0108]

[0124] Each base station 105 may provide communication coverage via one or more cells, e.g., macrocells, small cells, hotspots, or other types of cells, or various combinations thereof. The term “cell” may refer to a logical communication entity used for communication with the base station 105 (e.g., over a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) for distinguishing neighboring cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 in which the logical communication entity operates. Such a cell may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area, depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, an outer space between or overlapping the geographic coverage area 110, or the like.

[0109]

[0125] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 115 with a service subscription with the network provider that supports the macro cell. Small cells may be associated with lower-power base stations 105 compared to macro cells, and the small cells may operate in the same or different (e.g., licensed or unlicensed) frequency bands as the macro cell. A small cell may provide unrestricted access to UEs 115 with a service subscription with the network provider, or may provide restricted access to UEs 115 that have an association with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users at home or in the office, or the like). A base station 105 may support one or more cells and may support communication on one or more cells using one or more component carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, Narrowband IoT (NB-IoT), enhanced Mobile Broadband (eMBB), or others) that may provide access for different types of devices.

[0110]

[0126] In some examples, the base stations 105 may be mobile and therefore may provide communication coverage for moving 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 110 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0111]

[0127] The wireless communications 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 transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0112]

[0128] Some UEs 115, such as 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 technologies that enable devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices incorporating sensors or meters to measure or capture information and relay such information to a central server or application program that uses such information or presents the information to a human who interacts with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Example applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0113]

[0129] Some UEs 115 may be configured to use operating modes that reduce power consumption, such as half-duplex communication (e.g., a mode that supports one-way communication through transmission or reception, but not simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power-saving deep sleep mode when not engaged in active communication, operating on a limited bandwidth (e.g., pursuant to narrowband communication), or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that pertains to a predefined 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 of a carrier.

[0114]

[0130] The wireless communication system 100 may be configured to support ultra-reliable or low-latency communications, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission-critical communications. The UE 115 may be designed to support high-reliability, low-latency, or critical functionality (e.g., mission-critical functionality). Ultra-reliable communications may include private or group communications and may be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functionality may include service prioritization, and the mission-critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency may be used interchangeably herein.

[0115]

[0131] In some cases, the UE 115 may also be able to communicate directly with other UEs 115 via device-to-device (D2D) communication links 135 (e.g., using peer-to-peer (P2P) or D2D protocols). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105 or may otherwise be unable to receive transmissions from the base station 105. In some cases, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 transmits to every other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between the UEs 115 without the involvement of the base station 105.

[0116]

[0132] In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115). In some examples, the vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination thereof. The vehicles may signal information about traffic conditions, signal scheduling, weather, safety, emergency situations, or some other information relevant to the V2X system. In some cases, the vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with a network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communication, or both.

[0117]

[0133] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an Evolved Packet Core (EPC) or 5G Core (5GC) network, which may include at least one control plane entity (e.g., a Mobility Management Entity (MME), an Access and Mobility Management Function (AMF)) that manages 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 (UPF)) that routes packets or interconnects to external networks. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management, for UEs 115 served by base stations 105 associated with the core network 130. User IP packets are forwarded via the user plane entity, which may provide IP address allocation as well as other functions. The user plane entities may be connected to network operator IP services 150. Operator IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0118]

[0134] Some of the network devices, such as the base station 105, may include subcomponents, such as an access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with the UE 115 through some other access network transmitting entity 145, sometimes referred to as a radio head, a smart radio head, or a transmit / receive point (TRP). Each access network transmitting entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or integrated into a single network device (e.g., the base station 105).

[0119]

[0135] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 MHz to 300 GHz. The 300 MHz to 3 GHz region is commonly known as the ultra-high frequency (UHF) region or decimeter band because wavelengths range in length from approximately 1 decimeter to 1 meter. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently to allow a macrocell to serve UEs 115 located indoors. Transmission of UHF waves may involve smaller antennas and shorter ranges (e.g., less than 100 km) compared to transmissions using lower frequency and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0120]

[0136] The wireless communication system 100 may also operate in the very high frequency (SHF) region, using the frequency band from 3 GHz to 30 GHz, also known as the centimeter band, or in the very high frequency (EHF) region of the spectrum (e.g., 30 GHz to 300 GHz), also known as the millimeter band. In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas on each device may be smaller and more closely spaced than the UHF antennas. In some cases, this may facilitate the use of antenna arrays within the device. However, propagation of EHF transmissions may be subject to greater atmospheric attenuation than SHF or UHF transmissions, resulting in shorter ranges. The techniques disclosed herein may be used across transmissions using one or more different frequency ranges, and the designated use of bands across these frequency ranges may vary by country or regulatory body.

[0121]

[0137] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may use Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices such as the base station 105 and the UE 115 may use carrier sensing for collision detection and avoidance. In some cases, operation in the unlicensed band may be based on a carrier aggregation configuration associated with component carriers operating in a licensed band (e.g., LAA). Operation in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, D2D transmissions, or the like.

[0122]

[0138] The base station 105 or the UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or the UE 115 may be located in one or more antenna arrays or antenna panels that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located in an antenna assembly such as an antenna tower. In some cases, antennas or antenna arrays associated with the base station 105 may be located at various geographic locations. The base station 105 may have an antenna array with several rows and columns of antenna ports that the base station 105 may use to support beamforming of 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 panels may support radio frequency beamforming for signals transmitted through the antenna ports.

[0123]

[0139] Using MIMO communications, the base station 105 or UE 115 may exploit multipath signal propagation and increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques are sometimes referred to as spatial multiplexing. The multiple signals may be transmitted by a transmitting device, for example, via different antennas or different combinations of antennas. Similarly, the multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits related to the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). The different spatial layers may be associated with different antenna ports used for channel measurements and reporting. MIMO techniques include single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0124]

[0140] Beamforming, sometimes referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting or receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting and receiving devices. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array such that some signals propagating in a particular direction relative to the antenna array experience constructive interference and others experience destructive interference. Adjusting the signals communicated via antenna elements may include the transmitting or receiving device applying an amplitude offset, a phase offset, or both to signals carried via the antenna elements associated with the device. The adjustment associated with each of the antenna elements may be specified by a beamforming weight setting associated with a particular direction (e.g., with respect to the antenna array of the transmitting or receiving device, or with respect to some other direction).

[0125]

[0141] The base station 105 or the UE 115 may use beam sweeping techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform a beamforming operation for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by the base station 105 multiple times in different directions. For example, the base station 105 may transmit signals according to different beamforming weight settings associated with different directions of transmission. The transmission of different beam directions may be used (e.g., by a transmitting device such as the base station 105 or by a receiving device such as the UE 115) to identify beam directions for subsequent transmission and / or reception by the base station 105.

[0126]

[0142] The base station 105 may determine a mapping between the multiple SSBs of the two-step random access procedure and a random access message, where the random access message includes a random access preamble and a random access payload, and the mapping may include an association between one or more beams carrying the multiple SSBs 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 transmit information to the UE 115 including one or more of the mapping between the multiple SSBs of the two-step random access procedure and the random access message, and the association between one or more beams carrying the multiple SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message.

[0127]

[0143] The UE 115 may determine a mapping between multiple SSBs and a random access message, for example, associated with a two-step random access procedure. The UE 115 may also determine an association between one or more respective directional beams carrying the multiple SSBs and one or more additional respective directional beams carrying the random access message (e.g., a random access preamble and a random access payload of the random access message). Furthermore, the described techniques may, in some examples, include mapping time and frequency resources of the multiple SSBs to one or more ROs of the random access preamble and one or more PRUs of the random access payload over a PRACH configuration period of 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 switch procedure.

[0128]

[0144] Some signals, such as data signals associated with a particular receiving device, may be transmitted by the base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as the UE 115). In some examples, the beam direction associated with transmission along the single beam direction may be determined based on signals transmitted in different beam directions. For example, the UE 115 may receive one or more of the signals transmitted in different directions by the base station 105 and may report an indication to the base station 105 of the signal that the UE 115 received with the best signal quality or an otherwise acceptable signal quality.

[0129]

[0145] In some cases, transmission by a device (e.g., by the base station 105 or the UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may be precoded or deprecoded. The base station 105 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted by the base station 105 in one or more directions, the UE 115 may use similar techniques to transmit signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by the UE 115) or to transmit a signal in a single direction (e.g., to transmit data to a receiving device).

[0130]

[0146] A receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directional listening) when receiving various signals, such as synchronization signals, reference signals, beam selection signals, or other control signals, from the base station 105. For example, the receiving device may attempt multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight settings (e.g., different directional listening weight settings) applied to signals received at multiple antenna elements of the antenna array, or by processing received signals according to different receive beamforming weight settings applied to signals received at multiple antenna elements of the antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, the receiving device may receive along a single beam direction using a single receive configuration (e.g., when receiving a data signal). A single receive configuration may be aligned to a beam direction determined based on listening along 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 along multiple beam directions).

[0131]

[0147] The wireless communication system 100 may be a packet-based network operating according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. The Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. The Medium Access Control (MAC) layer may provide prioritized handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and management of RRC connections between the UE 115 and the base station 105 or core network 130 supporting radio bearers for user plane data. In the physical layer, transport channels may be mapped to physical channels.

[0132]

[0148] The UE 115 and the base station 105 may support retransmission of data to increase the likelihood of successful reception of the data. Hybrid Automatic Repeat Request (HARQ) feedback is one technique that increases the likelihood that data will be accurately received over the communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some cases, a device may support same-slot HARQ feedback, and the device may provide HARQ feedback in a particular slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot or according to some other time interval.

[0133]

[0149] 2 illustrates an example wireless communication system 200 supporting a four-step random access procedure in accordance with various aspects of the present disclosure. The wireless communication system 200 may include a base station 105-a and a UE 115-a, which may be examples of corresponding devices as described with reference to FIG. 1. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100. For example, the base station 105-a and the UE 115-a may support, among other advantages, robustness to beam association and improvements in random access messaging.

[0134]

[0150] The base station 105-a may perform a connection procedure (e.g., an RRC procedure, such as a cell acquisition procedure or a random access procedure) with the UE 115-a. For example, the base station 105-a and the UE 115-a may perform a random access procedure to establish a connection for communication. In another example, the base station 105-a and the UE 115-a may also perform a random access procedure to re-establish a connection after a connection failure (e.g., a radio link failure) with the base station 105-a, or to establish a connection for handover to another base station, or the like. The base station 105-a and the UE 115-a may also support multiple 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, sometimes referred to as an NR system.

[0135]

[0151] A connection procedure (e.g., a random access procedure) between the base station 105-a and the UE 115-a may correspond to, for example, at least one of the example radio access technologies described above. By way of example, in FIG. 2, the random access procedure may be associated with a 4G system and may be referred to as a four-step random access procedure. As part of the four-step random access procedure, the base station 105-a and the UE 115-a may transmit one or more messages (e.g., one or more handshake messages), such as random access message 205 (also referred to herein as msg1), random access message 210 (also referred to herein as msg2), random access message 215 (also referred to herein as msg3), and random access message 220 (also referred to herein as msg4).

[0136]

[0152] 2, the random access procedure may begin with the UE 115-a transmitting 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 convey 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 enable 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 transmit the random access message 205 to the base station 105-a, for example, on the PRACH.

[0137]

[0153] In some examples, prior to an attachment procedure between the base station 105-a and the UE 115-a, such as a four-step random access procedure, the base station 105-a may transmit 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 configuration information for performing the four-step random access procedure to the UE 115-a. Some examples of random access procedures, such as a four-step random access procedure, may be contention-based or contention-free. To transmit a random access message and initiate the random access procedure, the UE 115-a may first identify information, such as synchronization information for the base station 105-a and some system information for the wireless communication system 200. The base station 105-a may transmit (e.g., periodically) the synchronization information and system information in one or more of the SSBs and SIBs, respectively. In some examples, the synchronization information and system information may be transmitted in SSBs and physical broadcast channel (PBCH) blocks (e.g., SS / PBCH blocks, also referred to as SSBs). The base station 105-a may transmit a reference signal, such as a DMRS, on the PBCH to assist the UE 115-a in decoding the SSB and synchronizing with the base station 105-a.

[0138]

[0154] The SSBs may include any synchronization information or signaling that the UE 115-a may use to synchronize with downlink communications from the base station 105-a. For example, the SSBs 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 an SIB or multiple SIBs. In some examples, an SIB (e.g., SIB1) of the PBCH may include information such as a RACH or PRACH configuration regarding transmission opportunities (e.g., resources in time and frequency) for the UE 115-a to transmit, receive, or both signaling for a random access procedure.

[0139]

[0155] When performing a contention-based random access (CBRA) procedure, the base station 105-a may configure the UE 115-a with an SSB-to-PRACH opportunity (RO) association. The RO may be defined as a time and frequency resource in which the UE 115-a may transmit a random access message in the random access procedure, such as msg1 of a four-step random access message using a configured PRACH preamble format, on each directional beam. An association may be between each directional beam carrying multiple SSBs and each directional beam carrying msg1 of the four-step random access procedure on the RO.

[0140]

[0156] The UE 115-a may receive from the base station 105-a several (N) SSBs associated within a single RO and several (R) contention-based preambles per SSB per valid RO, where N and R are positive values. For example, the UE 115-a may be provided with N SS / PBCH blocks associated with one RO and R contention-based preambles per SS / PBCH block by higher layer parameters. In some examples, when N is less than a threshold, e.g., when N<1, one SS / PBCH block may be mapped to a portion of consecutive SSBs for consecutive valid ROs (e.g., 1 / N consecutive valid ROs). Alternatively, when N is equal to or greater than a threshold, e.g., when N≧1, N SS / PBCH blocks may be mapped to one valid RO. If N≧1, the R contention-based preambles with consecutive indices associated with SS / PBCH block N that map per RO may start from an initial preamble index. In some examples, the SS / PBCH block indices may be mapped to the ROs based in part on an order, such as ascending preamble indices within a single RO, ascending frequency resource indices for frequency-multiplexed ROs, or ascending time resource indices for time-multiplexed ROs. The base station 105-a and the UE 115-a may map multiple SSBs to one or more ROs during one or more PRACH configuration periods of an association pattern period. The association pattern period may be defined based on one or more PRACH configuration periods.

[0141]

[0157] The association pattern period, starting from an initial frame (e.g., frame 0), for mapping SS / PBCH blocks to ROs may be a value in a set determined by the PRACH configuration period according to Table 1, such that an SS / PBCH block is mapped to an RO at least once within the association pattern period. Thus, Table 1 may illustrate the mapping between the PRACH configuration period and the association pattern period (e.g., the number of PRACH configuration periods) from SS / PBCH blocks to ROs.

[0142] [Table 1]

[0143]

[0158] In some examples, if an integer number of SS / PBCH block-to-RO mapping cycles within an association pattern period have a set of ROs that are not mapped to N SS / PBCH blocks, the SS / PBCH block may not be mapped to a set of ROs. In some examples, an association pattern period may include one or more association pattern periods, and the pattern between ROs and SS / PBCH blocks may be determined to repeat, for example, every 160 milliseconds. If there are ROs that are not associated with an SS / PBCH block after an integer number of association pattern periods, they may not be used for PRACH transmission. The mapping between PRACH configuration periods and SS / PBCH block-to-RO association pattern periods is further described in more detail herein with reference to FIG. 3.

[0144]

[0159] 3 illustrates an example mapping configuration 300 that supports mapping between one or more PRACH configuration periods and association pattern periods in accordance with various aspects of the present disclosure. The mapping configuration 300 may implement aspects of the wireless communication systems 100 and 200, as described with reference to FIGS. 1 and 2. For example, the mapping configuration 300 may be implemented by the UE 115 for mapping between one or more PRACH configuration periods and association pattern periods based on configuration by the base station 105 to support, among other advantages, robustness to beam association and improvements in random access messaging, as described herein.

[0145]

[0160] The mapping configuration 300 may include a PRACH configuration period 305, which may be part of the PRACH association pattern period 310 for SSB-to-RO mapping. The PRACH configuration period 305 may include several 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 several ROs 320, which may be periodic frequency-division multiplexed. In the example of FIG. 3, four ROs 320 may be frequency-division multiplexed. In some examples, the PRACH configuration period 305 may have several periodic frequency-division multiplexed ROs 320. For example, all M PRACH slots 315 may include several frequency-division multiplexed ROs 320, where M is a positive value.

[0146]

[0161] In some examples, the mapping configuration 300 may be based on entries in Table 1, as described in FIG. 2. The entries in Table 1 may be based on higher layer parameters, such as one or more of msg1-FDM and ssb-perRACH-OccasionAndCB-PreamblesPerSSB. For example, the base station 105 may transmit the higher layer parameters to the UE 115 in an SIB, such as SIB1. Thus, according to the mapping configuration 300, the UE 115 and the base station 105 may map SSBs to ROs to support robustness to beam association and improvements in random access messaging.

[0147]

[0162] Returning to FIG. 2 , the preamble of the random access message 205 may, in some examples, be defined by a preamble sequence and a cyclic prefix. The preamble sequence may be defined based in part on a Zadoff-Chu sequence. The UE 115-a may additionally or alternatively use a guard period to address timing uncertainty of the random access message 205 transmission. For example, before initiating the random access procedure, the UE 115-a may acquire downlink synchronization with the base station 105-a based on a cell search procedure. However, because the UE 115-a has not yet acquired uplink synchronization with the base station 105-a, there may be uncertainty in uplink timing due to unknown location of the UE 115-a in the cell (e.g., the geographic coverage area of ​​the base station 105-a). In some examples, the uncertainty in uplink timing may be based in part on the dimensions (e.g., size, area) of the cell. Therefore, including a cyclic prefix in the random access message 205 may be beneficial in some instances to handle uncertainties in uplink timing.

[0148]

[0163] There may be several preamble sequences per cell (e.g., 64 preamble sequences). The UE 115-a may select a preamble sequence from a set of sequences in the cell (e.g., the geographic coverage area of ​​the base station 105-a) based in part on a random selection. In some examples, the UE 115-a may select a preamble sequence based in part on the amount of traffic the UE 115-a has for transmission on the uplink shared channel (UL-SCH). From the preamble sequence selected by the UE 115-a, the base station 105-a may determine the amount of uplink resources to be granted to the UE 115-a.

[0149]

[0164] Some examples of random access procedures may be contention-based or contention-free. When performing a CBRA procedure, the UE 115-a may select a preamble sequence from a set of sequences. That is, unless another UE (not shown) is performing a random access attempt using the same sequence at the same time instance, no collision occurs and the random access attempt may be detected by the base station 105-a. If the UE 115-a is performing a contention-free random access (CFRA) attempt, for example, for handover to a new cell, the preamble sequence to use may be explicitly signaled by the base station 105-a (e.g., in control information). To avoid collisions or interference, the base station 105-a may select a contention-free preamble sequence from sequences not associated with contention-based random access attempts.

[0150]

[0165] Upon 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 transmit 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 compared to 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 the detected preamble sequence for which the response is valid, a timing advance parameter determined in part based on the detected preamble sequence, a scheduling grant indicating time and frequency resources to be used by the UE 115-a for transmission of the UE 115-a's next random access message transmission, or a network identifier (e.g., a random access radio network temporary identifier (RA-RNTI)) for further communication with the UE 115-a, or the like.

[0151]

[0166] In some examples, the base station 105-a may transmit a random access message 210, which may be scheduled on a PDCCH using an identity reserved for random access messaging, e.g., an RA-RNTI. The UE 115-a may monitor the PDCCH to detect and receive a random access message (e.g., the random access message 210). In some examples, the UE 115-a may monitor the PDCCH for a random access message transmission 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 receive a random access message transmission from the base station 105-a, the random access attempt may be declared a failure, and the random access procedure in FIG. 2 may be repeated. However, in subsequent attempts, the random access response window may be adjusted (e.g., increased or decreased in length (duration)).

[0152]

[0167] Once the UE 115-a successfully receives the random access message 210, the UE 115-a may acquire uplink synchronization with the base station 105-a. In some examples, a unique identifier within the cell (e.g., a cell RNTI (C-RNTI)) may be assigned to the UE 115-a prior to data transmission from the UE 115-a. In some examples, depending on the state of the UE 115-a (e.g., an RRC connected state, an RRC idle state), additional messages (e.g., connection request messages) may need to be exchanged to set up a connection between the base station 105-a and the UE 115-a. The UE 115-a may transmit any necessary messages, such as a random access message 215, to the base station 105-a using the UL-SCH resources (or PUSCH resources) assigned in the random access message 210. The random access message 210 may include a UE identifier for contention resolution. If the UE 115-a is in an RRC connected state, for example, the UE identifier may be the C-RNTI. Otherwise, the UE identifier may be specific to the UE 115-a.

[0153]

[0168] The base station 105-a may receive the random access message 215 and may respond appropriately by transmitting a random access message 220, which may be, for example, a contention resolution message. When multiple UEs (including the UE 115-a) are simultaneously performing random access attempts using the same preamble sequence, these UEs may end up listening for the same response message (e.g., the random access message 220). Each UE (including the UE 115-a) may receive the random access message 220 and compare the identifier (e.g., a 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., the UE 115-a) may declare the random access procedure successful. A UE that does not identify a match between the identifiers is considered to have failed the random access procedure and may repeat the random access procedure with the base station 105-a. As a result of the connection procedure, the base station 105-a and the UE 115-a may establish a connection for communication.

[0154]

[0169] 2 may be effective in facilitating random access for the UE 115-a, there may be unnecessary latency associated with this procedure. For example, the latency associated with a contention-based protocol for random access messaging may use up additional resources for the UE 115-a. The techniques described herein may provide benefits to the UE 115-a by reducing or eliminating the latency associated with processes related to initial channel access.

[0155]

[0170] 4 illustrates an example of a wireless communication system 400 supporting a two-step random access procedure in accordance with various aspects of the present disclosure. The wireless communication system 400 may include a base station 105-b and a UE 115-b, which may be examples of corresponding devices as described with reference to FIG. 1. In some examples, the wireless communication system 400 may implement aspects of the wireless communication systems 100 and 200. For example, the base station 105-b and the UE 115-b may support, among other advantages, robustness to beam association and improvements in random access messaging.

[0156]

[0171] The base station 105-b and the UE 115-b may support multiple 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, sometimes referred to as an NR system, as described with reference to FIG. 2. A connection procedure (e.g., a random access procedure) between the base station 105-b and the UE 115-b may correspond to at least one of these example radio access technologies. In the example of FIG. 4, the random access procedure may be associated with a 5G system and may be referred to as a two-step random access procedure. As part 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 four-step random access procedure, as described in FIG. 2, to reduce latency associated with the contention-based aspect of the two-step random access procedure.

[0157]

[0172] For example, the UE 115-b may transmit a single message such as a random access message 405 (also referred to herein as msgA), and the base station 105-b may transmit 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 and 3 of a four-step random access procedure, and the random access response message 410 (e.g., msgB) may combine aspects of msg2 and 4 of the four-step random access procedure. When supporting both two-step and four-step random access procedures, it may be important that the UE 115-b be configured to support beam association for both random access procedures.

[0158]

[0173] When supporting both two-step and four-step random access procedures, the base station 105-b and the UE 115-b may start with one random access procedure (e.g., a two-step random access procedure) and fall back to another random access procedure (e.g., a four-step random access procedure) if necessary. The base station 105-b may select or assign a priority to the random access procedure based on conditions (e.g., traffic type, network load). For example, the base station 105-b may be configured to use the four-step random access procedure over the two-step random access procedure to reduce overhead for some scenarios (e.g., traffic load, link quality measurements, system load, quality of service (QoS), etc.) because the base station 105-b may have to prepare msgA resources for the two-step random access, which may involve greater overhead compared to msg1 transmission via the four-step random access procedure. Additionally or alternatively, the base station 105-b may select the random access procedure based on the UE 115-b capabilities to support the random access procedure. For example, if the UE 115-b supports both two-step and four-step random access procedures, the base station 105-b may select either the two-step random access procedure or the four-step random access procedure to initiate the initial access procedure, otherwise, the base station 105-b may select the random access procedure supported by the UE 115-b.

[0159]

[0174] Returning to the random access messaging example, the UE 115-b may transmit a random access message 405 to the base station 105-b. The random access message 405 may include a random access preamble and a random access payload (e.g., a physical uplink shared channel (PUSCH) carrying the payload), and the information in the random access message 405 (e.g., msgA) includes content or aspects equivalent to msg3 of the four-step random access procedure. The random access message 405 transmission in the two-step random access procedure is described in further detail herein with reference to FIG. 5.

[0160]

[0175] FIG. 5 illustrates an example of a transmit chain 500 supporting beam association in a random access procedure according to aspects of the present disclosure. In some examples, the transmit chain 500 may implement aspects of the wireless communication system 400. For example, referring to FIG. 4, the transmit chain 500 may illustrate how a random access message 405 (e.g., msgA) of a two-step random access procedure is configured (e.g., encoded, scrambled, mapped, etc.) by the UE 115-b before the UE 115-b transmits the random access message 405 to the base station 105-b. The UE 115-b may use an encoder 505 to encode the payload portion of the random access message 405. In some examples, the encoder 505 may be a low-density parity check (LDPC) encoder. After encoding the payload of the random access message 405, the UE 115-b passes the payload through a scrambler 510, which may scramble the encoded bits. After scrambling the encoded bits, the UE 115-b may then perform modulation 515. In some examples, modulation 515 may include linear modulation.

[0161]

[0176] The UE 115-b may then perform precoding 520 (e.g., transform precoding) on ​​the modulated bits. The UE 115-b may then use an inverse fast Fourier transform (IFFT) 525 after precoding to transform the bits. After the IFFT 525, the UE 115-b may use a multiplexer (MUX) 530. In some examples, the multiplexer 530 may allow the UE 115-b to multiplex the DMRS 545 (e.g., using the DMRS sequence in the reference signal resource as described herein). The UE 115-b may then perform mapping 535. In some examples, the UE 115-b may perform the mapping based on a preamble 540. For example, the preamble 540 may indicate one or more of a predefined mapping rule between the preamble and the payload of the random access message 405, a reference signal resource, and a reference signal sequence. In some examples, the mapping may include mapping of time, frequency, and space (e.g., beam, panel) resources. The preamble 540 may provide an early 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) piggybacking on the PUSCH. The UE 115-b may then transmit the random access message 405 after performing different steps.

[0162]

[0177] Returning to FIG. 4, an advantage of the two-step random access procedure compared to the four-step random access procedure may be that the UE 115-b may be able to transmit data (e.g., a random access payload on a PUSCH) to the base station 105-b without needing to be in an RRC connected state for one data transmission. The base station 105-b may monitor the PUSCH for a random access preamble or a random access payload of the random access message 405. In some examples, the base station 105-b may determine the absence of a random access preamble or a random access payload of the random access message 405 based on the monitoring. The absence of a random access preamble or a random access payload of the random access message 405 may result in a random access procedure failure.

[0163]

[0178] In some examples, after successfully receiving the random access message 405, the base station 105-b may construct and transmit a random access response message 410 to the UE 115-b. For example, the base station 105-b may transmit the random access response message 410 to the UE 115-b on a DL-SCH, a PDSCH, or a PDCCH. The random access response message 410 may include at least one of a network identifier for 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 procedure backoff indication, or both. The timing backoff indication may be related to the timing of retrying a random access procedure (e.g., a two-step random access procedure), and the random access procedure backoff indication may be related to switching from a current random access procedure to an alternative random access procedure (e.g., a four-step random access procedure).

[0164]

[0179] In an example of a multi-beam implementation of a random access procedure, such as a two-step random access procedure, the transmission of the random access preamble on the PRACH and the transmission of the PUSCH carrying the random access payload may occur over one or more occasions. For example, the transmission of the random access preamble on the PRACH may occur over an RO, which may include time and frequency resources. In another example, the transmission of the PUSCH carrying the random access payload may occur over a PO, which may include time and frequency resources (e.g., a PURSH resource unit (PRU) including PUSCH resources and DMRS resources).

[0165]

[0180] One or more opportunities may share an association. In some examples, the RO and PO may have a one-to-one mapping. For example, a single RO may map to a single respective PO. In some other examples, the RO and PO may have a one-to-many mapping. For example, a single RO may map to several POs. Alternatively, multiple ROs may map to a single PO using a many-to-one mapping. The UE 115-b may multiplex transmissions of a random access preamble across time and frequency resources of multiple ROs. Similarly, it may be advantageous for the UE 115-b to multiplex transmissions of a PUSCH carrying a random access payload across time and frequency resources of multiple POs.

[0166]

[0181] In some examples, when supporting both two-step and four-step random access procedures, the base station 105-b may be able to configure separate ROs for the two-step random access procedure and the four-step random access procedure. Alternatively, the base station 105-b may be able to configure a shared RO for the two-step random access procedure and the four-step random access procedure, but may configure (use) separate preambles to avoid interference issues. In some examples, when supporting both two-step and four-step random access procedures, the base station 105-b and the UE 115-b may configure beam establishment during initial access for the two-step random access procedure for improved coverage and interference mitigation.

[0167]

[0182] In some examples, when supporting both two-step and four-step random access procedures, the base station 105-b and the UE 115-b may be capable of beam switching for random access message retransmissions (e.g., msgA retransmissions) and fallback to a different random access procedure (e.g., from a two-step random access procedure to a four-step random access procedure). To improve beam establishment reliability for different random access procedures (e.g., a two-step random access procedure) and reduce complexity in the wireless communication system 400, the base station 105-b and the UE 115-b may support resource configuration and signaling support for beam association between multiple SSBs and random access messaging resources (e.g., msgA ROs and msgA PRUs). One or more SSBs and one or more ROs may share an association. In some examples, the SSBs and ROs may have a one-to-one mapping. For example, a single SSB may map to a single respective RO. In other examples, the SSBs and ROs may have a one-to-many mapping. For example, a single SSB may map to several ROs. Alternatively, multiple SSBs may be mapped to a single RO using a many-to-one mapping. The base station 105-b may multiplex transmissions of SSBs across the time and frequency resources of multiple ROs. Similarly, each directional beam associated with an SSB may have an association with each directional beam associated with an RO (and / or PO).

[0168]

[0183] Base station 105-b and UE 115-b may, in some examples, map SS / PBCH blocks to ROs according to Table 2, which may implement an aspect of Table 1 such that an SS / PBCH block is mapped to an RO at least once within an association pattern period in a two-step random access procedure. Thus, Table 2 may illustrate the mapping capabilities between the PRACH configuration period and the SS / PBCH block-to-RO association pattern period for both two-step and four-step random access procedures. In some examples, the association pattern period for a two-step random access procedure may be a multiple of the association pattern period for a four-step random access procedure (e.g., two-step random access procedure association pattern period ≈ K * four-step random access procedure association pattern period, where K ≥ 1 and K is an integer).

[0169] [Table 2]

[0170]

[0184] Resource configuration and signaling support for beam association between SSB and random access messaging resources is described in further detail herein with reference to Figures 6A and 6B.

[0171]

[0185] FIG. 6A illustrates an example channel structure 600-a supporting beam association in a random access procedure according to aspects of the present disclosure. The channel structure 600-a may implement aspects of the wireless communication systems 100, 200, and 400. For example, the channel structure 600-a may support robustness to beam association and improvements in random access messaging, among other advantages, as described herein. The UE 115 may transmit a random access message 605 to the base station 105 according to the channel structure 600-a. The random access message 605 may 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 for the random access message 605 may support a CBRA procedure or a CFRA procedure over time and frequency resources.

[0172]

[0186] The random access message 605 may include a random access preamble 610 and a random access payload 615. In some examples, the bandwidths 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, and the random access preamble 610 (e.g., having the PRACH preamble signal 620) may serve multiple purposes. For example, the random access preamble 610 may facilitate timing offset estimation by the base station 105. Additionally, the random access preamble 610 may provide an early indication of the payload size and resource allocation for the random access payload 615 (e.g., this may provide a more efficient solution than UCI piggybacking on a PUSCH that includes the random access payload 615).

[0173]

[0187] In some examples, resource allocation for the random access payload 615 may be based on a predefined mapping rule between the random access preamble 610 and the random access payload 615, which may be indicated in 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 the user plane and the control plane.

[0174]

[0188] Additionally, there may be guard times (GTs) 625 between each portion of the random access message 605 (e.g., between the random access preamble 610 and the random access payload 615). A first GT 625-a may be present between the random access preamble 610 and the random access payload 615, and a second GT 625-b may be present after the random access payload 615 and the subsequent random access preamble 610. Additionally, the base station 105 may 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 may extend the random access message 605 to occur over more than one symbol (e.g., or a different TTI length). In some examples, each GT 625 may be a TxG. G and the transmission gap 630 may have a duration equal to T gIn some examples, the base station 105 may configure guard bands (GBs) 640. For example, the base station 105 may 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.

[0175]

[0189] 6B illustrates an example mapping configuration 600-b that supports beam association in a random access procedure according to an aspect of the present disclosure. The mapping configuration 600-b may implement aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 600-b may support, among other advantages, robustness to beam association and improvements in random access messaging, as described herein. The base station 105 may configure a mapping between multiple SSBs 650 and one or more PRACHs 655 of the random access preamble of a random access message (e.g., msgA) on one or more ROs and one or more PRUs 660 of the random access payload of the random access message (e.g., msgA), and the UE 115 may determine this mapping based on the configuration by the base station 105.

[0176]

[0190] Within an association pattern period, the base station 105 may configure slots that include one or more PRACHs 655 on one or more ROs, one or more random access payloads on one or more PRUs 660, etc. In some examples, the base station 105 may associate one or more SSBs 650 with one or more PRACHs 655 and one or more PRUs 660 within a PRACH association pattern period (e.g., using parameter association). For example, a first SSB 650-a may be associated with a first PRACH 655 and a first PRU 660, and a second SSB 650-b may be associated with a second PRACH 655 and a second PRU 660. In some examples, the UE 115 may determine, based on the mapping, an association between one or more respective directional beams carrying the plurality of SSBs 650 and one or more additional respective directional beams carrying the random access payload of the random access message (e.g., msgA) along with the PRACH 655 (e.g., the random access preamble of the random access message (e.g., msgA)). In some examples, the base station 105 and the UE 115 may support different beam associations between the plurality of SSBs and the random access message (e.g., msgA) of a two-step random access procedure.

[0177]

[0191] In some examples, to support different beam associations between SSBs and msgA, the base station 105 may transmit configuration information for the beam association to the UE 115 via SIB signaling or RRC signaling. The UE 115 may determine the beam association according to one or more factors. For example, the UE 115 may determine the association between one or more respective directional beams carrying the plurality of SBBs 650 and one or more additional respective directional beams carrying the random access message (e.g., msgA) based in part on an RO index of one or more ROs. In some examples, the UE 115 may determine the association between one or more respective directional beams carrying the plurality of SBBs 650 and one or more additional respective directional beams carrying the random access message (e.g., msgA) based in part on a preamble sequence of a random access preamble of the random access message (e.g., msgA). In some examples, the UE 115 may determine an association between one or more respective directional beams carrying the plurality of SBBs 650 and one or more additional respective directional beams carrying a random access message (e.g., msgA) based in part on a PRU index associated with one or more PRUs. In some other examples, the UE 115 may determine an association between one or more respective directional beams carrying the plurality of SBBs 650 and one or more additional respective directional beams carrying a random access message (e.g., msgA) based in part on a UCI piggybacking a PUSCH. Thus, the UE 115 may determine the beam association according to one or more factors, such as a msgA RO index, a msgA preamble sequence, a msgA PRU index, and a UCI piggybacking.

[0178]

[0192] The random access preamble and the random access payload of a random access message (e.g., msgA) of a two-step random access procedure may be associated with different SSBs 650. For example, referring to FIG. 6A, T g and T G and the sum (for example, T g +T G ) is greater than a threshold, the random access preamble and the random access payload of a random access message (e.g., msgA) of a two-step random access procedure may be associated with different SSBs 650. For example, with reference to Figures 6A and 6B, the random access preamble 610 (carried on the PRACH 655) may be associated with SSB 650-a, while the random access payload 615 (and PRU 660) may be associated with SSB 650-b. In some examples, one or more PRUs 660 that share time domain resources may be grouped together and mapped to the same SSB 650 or the same subset of SSBs 650.

[0179]

[0193] As an example, the UE 115 may determine that one or more PRUs 660 of a random access payload share time / frequency resources and determine a mapping between the one or more PRUs 660 of the random access payload that share the time / frequency resources and one or more SSBs 650 of the set of SSBs 650 or a subset of SSBs of the set of SSBs 650. The subset of SSBs may be grouped. In some examples, the base station 105 and the UE 115 may map the one or more PRUs 660 of the random access payload that share the time / frequency resources to one or more SSBs 650 based in part on analog beamforming 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.

[0180]

[0194] Returning to FIG. 4, in some examples, the base station 105-b and the UE 115-b may support RO sharing between multiple random access procedures. For example, the base station 105-b and the UE 115-b may support RO sharing between a two-step random access procedure and a four-step random access procedure. In some examples, the base station 105-b may configure RO sharing between multiple random access procedures according to system information signaling or RRC signaling. The base station 105-b may decide to configure RO sharing between multiple random access procedures according to one or more conditions. For example, the base station 105-b may decide to configure RO sharing based on one or more of the UE capabilities of the UE 115-b, the random access procedure fallback capability of the UE 115-b, the load balancing capability (e.g., for more efficient RO sharing), or multiplexing of CFRA and CBRA.

[0181]

[0195] The UE 115-b may receive, from the base station 105-b, N SSBs related to 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 the random access message (e.g., msgA) of the two-step random access procedure and the preamble sequence of the random access message (e.g., msg1) of the four-step random access procedure may consist of two subsets of preamble sequences.

[0182]

[0196] In some examples, the UE 115-b may determine that the number N of SSBs meets a threshold and determine that 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 are composed of different subsets of preamble sequences. In some examples, the indices of the preamble sequences in each subset may be consecutive. Thus, the UE 115-b may determine that the indices of the preamble sequences in each subset of the subsets of preamble sequences are consecutive (e.g., of msgA and msg1). In some examples, the preamble sequences in each subset may not overlap to avoid interference. Thus, the base station 105-b may use the same respective directional beam to receive both random access messages, e.g., msgA related to the two-step random access message and msg1 related to the four-step random access message. Beam association between SSBs and random access messaging resources is described in further detail herein with reference to FIG. 7A.

[0183]

[0197] 7A illustrates an example mapping configuration 700-a supporting beam association in a random access procedure according to aspects of the present disclosure. The mapping configuration 700-a may implement aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 700-a may support, among other benefits, robustness to beam association and improvements in random access messaging, as described herein. The base station 105 may transmit SSBs 705-a to the UE 115 on the same respective directional beams 725-a. The SSBs 705-a may correspond to a random access preamble 710-a of a random access message (e.g., msgA) related to a two-step random access procedure and a random access message 715-a (e.g., msg1) related to a four-step random access procedure. The random access preamble 710-a for a random access message (e.g., msgA) related to a two-step random access procedure and the random access message 715-a (e.g., msg1) related to a four-step random access procedure may share an RO 720-a and be configured with different preamble sequences, as described herein. Thus, by using different preamble sequences that may distinguish the transmissions, the base station 105 may also receive the random access preamble 710-a for a random access message (e.g., msgA) related to a two-step random access procedure and the random access message 715-a (e.g., msg1) related to a four-step random access procedure from the UE 115 on the same respective directional beam.

[0184]

[0198] Returning to FIG. 4, in some examples, the 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 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 examples where the number N of SSBs is above a 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 respective 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 subsets of SSBs. The mapping to the subsets of SSBs may be contiguous or non-contiguous in the time domain. In some examples, depending on the spatial separation of the respective directional beams mapped to 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, the subsets of preamble sequences associated with each respective directional beam may have similar but different sizes. Base station 105-b may use different respective directional beams to receive 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 from UE 115-b. Beam association between SSBs and random access messaging resources is described in further detail herein with reference to FIG. 7B.

[0185]

[0199] FIG. 7B illustrates an example mapping configuration 700-b supporting beam association in a random access procedure according to aspects of the present disclosure. The mapping configuration 700-b may implement aspects of the wireless communication systems 100, 200, and 400. For example, the mapping configuration 700-b may support, among other advantages, robustness to beam association and improvements in random access messaging, as described herein. When supporting multiple random access procedures, the base station 105 may transmit different SSBs 705 to the UE 115-b on the same or different respective directional beams 725-b. For example, the base station 105 may transmit SSBs 705-b on respective directional beams 725-b corresponding to the random access preamble 710-b of a random access message related to a two-step random access procedure and transmit SSBs 705-c on respective directional beams 725-c corresponding to the random access message 715-b related to a four-step random access procedure. Alternatively, the base station 105 may transmit SSB 705-b corresponding to the random access preamble 710-b of a random access message related to a two-step random access procedure and SSB 705-c corresponding to the random access message 715-b related to a four-step random access procedure on the same respective directional beam 725-d. As described herein, the random access preamble 710-a of the random access message related to a two-step random access procedure (e.g., msgA) and the random access message 715-b related to a four-step random access procedure (e.g., msg1) may share an RO 720-b or may be configured with different preamble sequences.Thus, by using different preamble sequences that may distinguish the transmissions, the base station 105 may also receive a random access preamble 710-b for a random access message (e.g., msgA) related to a two-step random access procedure and a random access message 715-b (e.g., msg1) related to a four-step random access procedure from the UE 115 on the same respective directional beam.

[0186]

[0200] Returning to FIG. 4, in some examples, within an association pattern period of a two-step random access procedure, the random access message 405 (e.g., the random access preamble and the random access payload of the random access message 405) may be retransmitted multiple times by the UE 115-b. In some examples, the UE 115-b may 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 may support beam switching, e.g., switching of their respective directional beams (e.g., the receive beam of the base station 105-b and the transmit beam of the UE 115-b) for retransmission of the random access message 405. In some examples, the UE 115-b may support beam switching (e.g., switching the transmit beam) for both the random access preamble of the random access message 405 and the random access payload of the random access message 405. Similarly, the base station 105-b may support beam switching (e.g., switch 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, a beam switch (e.g., switch receive beams) may be indicated based on one or more conditions, such as 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.

[0187]

[0201] In some examples, resources (e.g., preconfigured in the time domain, frequency domain, space domain, or code domain) used for transmission and retransmission of the random access message 405 may be different based on the RRC state (e.g., RRC idle state, RRC inactive state). For example, if the random access message 405 is allowed to be retransmitted M times within an association pattern period of a two-step random access procedure, the UE 115-b may use resources in a first resource set X when 1≦retx counter≦α·M. Alternatively, the UE 115-b may use resources in a second resource set Y when α·M+1≦re-tx counter≦M, where the first resource set is different from the second resource set. In some examples, for RRC connected states, reference signals (e.g., channel state information (CSI) reference signals, sounding reference signals) may be configured to assist beam switching. In some examples, the base station 105-b and the UE 115-b may jointly perform a beam switch (e.g., jointly switch between a receive beam and a transmit beam). In some examples, the base station 105-b and the UE 115-b may enable a beam switch based in part on an association rule between SSBs and resources in the random access message 405 mapping, or triggered by a preamble, a reference signal, or a UCI.

[0188]

[0202] The base station 105-b and the UE 115-b may support a beam switch for a random access fallback procedure or a random access switch procedure from a two-step random access procedure to a four-step random access procedure. For example, when a fallback for a switch occurs, a new transmission can start with msg1 or msg3 of the four-step random access procedure. In some examples, a beam switch may be enabled for the random access fallback procedure or the random access switch procedure. For example, when a new transmission starts with msg3 of the four-step random access procedure, a beam switch can be commanded by the base station 105-b via downlink control information (DCI). Alternatively, when a new transmission starts with msg1 of the four-step random access procedure, a beam switch can be pre-configured based on an association rule between SSB and RO. Thus, the described techniques may include features for improved resource utilization and allocation for random access messages and improved reliability for random access messages, among other advantages, and may facilitate low latency for the random access procedure in some examples.

[0189]

[0203] FIG. 8 illustrates an example process flow 800 supporting beam association in a random access procedure according to an aspect of the present disclosure. In some examples, process flow 800 may implement aspects of wireless communication systems 100, 200, and 400, as described with reference to FIGS. 1, 2, and 4. For example, process flow 800 may include base station 105-c and UE 115-c, which may be examples of corresponding devices, as described with reference to FIGS. 1 and 2. In the following description of process flow 800, operations between base station 105-c and UE 115-c may be transmitted in a different order than 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 different times. 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 to UE 415 resource utilization and allocation for random access messaging, improved reliability for random access messaging, and in some examples may facilitate lower latency for random access procedures, among other benefits.

[0190]

[0204] 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 multiple 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, sometimes referred to as an NR system. The random access procedure may correspond to at least one of the exemplary radio access technologies listed above. In FIG. 8, by way of 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, or the like. Alternatively, the random access procedure may occur after one or more operations of process flow 800.

[0191]

[0205] At 805, the base station 105-c may determine a mapping between multiple SSBs of a random access procedure, such as a two-step random access procedure, and a random access message. In some examples, the base station 105-c may determine, based in part on the mapping, an association between one or more beams carrying the multiple SSBs and one or more additional beams carrying, for example, a random access preamble and a random access payload of the random access message. The base station 105-c may map resources of the multiple SSBs to one or more ROs of the random access preamble of the random access message and one or more PRUs of the random access payload over a PUSCH configuration period of an association pattern period of the random access procedure. At 810, the base station 105-c may transmit signaling including the configuration (e.g., mapping and association information) to the UE 115-c. In some examples, the signaling may include system information signaling, RRC signaling, or the like. At 815, the UE 105-c may determine, e.g., based in part on the signaling, a mapping between the plurality of SSBs of the random access procedure and the random access message. At 820, the UE 115-c may determine an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access message.

[0192]

[0206] 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 transmit one or more SSBs to the UE 115-c on one or more respective directional beams corresponding to one or more ROs. The random access procedure may cause the UE 105-c to transmit a random access message (also referred to as msgA) toward the base station 105-c. When the random access procedure is a two-step random access procedure, the msgA transmitted 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 transmit the 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 such that the UE 115-c can recognize the UE 115-c from other UEs. The UE 115-c may transmit msgA on one or more respective directional beams based on the mapping and beam association. The base station 105-c may transmit a random access message (also referred to as msgB) to the UE 115-c. msgB may be a random access response to a received random access message (e.g., msgA) from the UE 115-c. In some examples, the base station 105-c may transmit msgB to the UE 115-c based in part on a UE contention resolution identifier, RA-RNTI, or the like. For example, as part of a random access procedure, the base station 105-c may transmit msgB on the DL-SCH according to the RA-RNTI. The base station 105-c may transmit msgB on one or more respective directional beams based on the mapping and beam association.

[0193]

[0207] 9 shows a block diagram 900 of a device 905 that supports beam association in a random access procedure according to an aspect of the present disclosure. The device 905 may be an example of an aspect of a UE 115 described herein. The device 905 may include a receiver 910, a UE communications 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).

[0194]

[0208] The receiver 910 may receive information such as packets, user data, or control information related to various information channels (e.g., control channels, data channels, information regarding beam association in random access procedures, etc.). The information may be passed to other components of the device 905. The receiver 910 may be an example of an aspect of a transceiver 1220, as described with reference to FIG. 12. The receiver 910 may utilize a single antenna or a set of antennas.

[0195]

[0209] The UE communications manager 915 may determine, based on an indication in the system information signaling or the RRC signaling, a mapping between the plurality of SSBs of the two-step random access procedure and a random access message, where the random access message includes a random access preamble and a random access payload, and may determine, based on the mapping, an association between one or more beams carrying the plurality of SSBs 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 the base station. The UE communications manager 915 may be an example of an aspect of the UE communications manager 1210 described herein.

[0196]

[0210] The UE communications manager 915, or any of its subcomponents, may be implemented in hardware, processor-executed code (e.g., software or firmware), or any combination thereof. If implemented in processor-executed code, the functions of the UE communications manager 915, or any of 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.

[0197]

[0211] The UE communications manager 915 or its subcomponents may be physically located in various locations, including being distributed such that some of the functionality is implemented by one or more physical components at different physical locations. In some examples, the UE communications manager 915 or its subcomponents may be separate and distinct components according to various aspects of the present disclosure. In some examples, the UE communications manager 915 or its subcomponents may be combined with one or more other hardware components, including, but not limited to, an input / output (I / O) component, a transceiver, a network server, another computing device, one or more other components described in this disclosure, or a combination thereof according to various aspects of the present disclosure.

[0198]

[0212] The transmitter 920 may transmit signals generated by other components of the device 905. In some examples, the transmitter 920 may be co-located with the receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of an aspect of the transceiver 1220, as described with reference to FIG. 12. The transmitter 920 may utilize a single antenna or a set of antennas.

[0199]

[0213] 10 shows a block diagram 1000 of a device 1005 supporting beam association in a random access procedure according to an aspect of the present disclosure. The device 1005 may be an example of an aspect of the device 905 or the UE 115 described herein. The device 1005 may include a receiver 1010, a UE communications 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).

[0200]

[0214] The receiver 1010 may receive information such as packets, user data, or control information related to various information channels (e.g., control channels, data channels, information regarding beam association in random access procedures, etc.). The information may be passed to other components of the device 1005. The receiver 1010 may be an example of an aspect of a transceiver 1220, as described with reference to FIG. 12. The receiver 1010 may utilize a single antenna or a set of antennas.

[0201]

[0215] UE communications manager 1015 may be an example of aspects of UE communications manager 915 described herein. UE communications manager 1015 may include a mapping component 1020, an associating component 1025, and an access component 1030. UE communications manager 1015 may be an example of aspects of UE communications manager 1210 described herein.

[0202]

[0216] The mapping component 1020 may determine, based on the indication, a mapping between the plurality of SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload. The association component 1025 may determine, based on the mapping, an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The access component 1030 may perform the two-step random access procedure with the base station.

[0203]

[0217] The transmitter 1035 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1035 may be co-located with the receiver 1010 in a transceiver module. For example, the transmitter 1035 may be an example of an aspect of the transceiver 1220, as described with reference to FIG. 12. The transmitter 1035 may utilize a single antenna or a set of antennas.

[0204]

[0218] 11 shows a block diagram 1100 of a UE communications manager 1105 supporting beam association in a random access procedure according to an aspect of the present disclosure. The UE communications manager 1105 may be an example of an aspect of the UE communications manager 915, the UE communications manager 1015, or the UE communications manager 1210 described herein. The UE communications 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 fallback component 1150. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0205]

[0219] The mapping component 1110 may determine, based on the indication, a mapping between multiple SSBs of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload. In some examples, the mapping component 1110 may map resources of the multiple SSBs to one or more ROs of the access preamble and one or more PRUs of the random access payload over a PRACH configuration period of an association pattern period of the two-step random access procedure. In some examples, the mapping component 1110 may determine, based on the second indication, an association pattern period of the two-step random access procedure based on a factor value of an association pattern period of the four-step random access procedure, the factor value including an integer value within a finite range configured by the network.

[0206]

[0220] In some examples, the mapping component 1110 may determine a mapping between one or more PRUs of a random access payload that share time / frequency resources and an SSB of the plurality of SSBs or a portion of the SSBs of the plurality of SSBs, where the portion of the SSBs of the plurality of SSBs are grouped. In some examples, the mapping component 1110 may map one or more PRUs of a random access payload that share time / frequency resources to an SSB of the plurality of SSBs based on analog beamforming capabilities. In some examples, the mapping component 1110 may map one or more PRUs of a random access payload that share time / frequency resources to a portion of the SSBs of the plurality of SSBs based on digital beamforming capabilities. In some cases, the random access preamble and the random access payload of a random access message are associated with different SSBs of the plurality of SSBs based on the duration of a guard period associated with the random access preamble and a gap duration between the random access preamble and the random access payload. 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 among several SSBs.

[0207]

[0221] The correlation component 1115 may determine, based on the mapping, an association between one or more beams carrying the plurality of SSBs 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 correlation component 1115 may determine a second association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message over an additional PRACH configuration period of a second association pattern period of the two-step random access procedure. In some examples, the second association over the second association pattern period of the two-step random access procedure may be different from the association over the association pattern period of the two-step random access procedure.

[0208]

[0222] In some examples, determining an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message is based on a physical random access channel opportunity index of one or more ROs, and the indication includes the physical random access channel opportunity index. In some examples, determining an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message is based on a preamble sequence of the random access preamble, and the indication includes the preamble sequence. In some examples, determining an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message is based on a physical uplink shared channel resource unit index associated with one or more PRUs of the random access payload, and the indication includes the physical uplink shared channel resource unit index. In some examples, determining the association between one or more beams carrying multiple SSBs and one or more additional beams carrying a random access preamble and a random access payload of the random access message is based on multiplexing UCI onto one or more of the random access preamble and the random access payload of the random access message, and the indication includes the multiplexing of the UCI.

[0209]

[0223] The access component 1120 may perform a two-step random access procedure with the base station. In some examples, the access component 1120 may transmit a random access message of the two-step random access procedure to the base station during an association pattern period. In some examples, the access component 1120 may retransmit the random access message of the two-step random access procedure during an association pattern period based on a retransmission counter being less than a threshold.

[0210]

[0224] The signaling component 1125 may receive signaling from a base station including an indication including an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. In some cases, the signaling includes system information signaling. In some cases, the signaling includes RRC signaling.

[0211]

[0225] 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 determines that the resources for transmitting the random access message of the two-step random access procedure to the base station during the association pattern period are the same as the resources for retransmitting the random access message of the two-step random access procedure during the association pattern period based on the retransmission counter satisfying a threshold. In some examples, the resource component 1130 determines that the resources for transmitting the random access message of the two-step random access procedure to the base station during the association pattern period are different from the resources for retransmitting the random access message of the two-step random access procedure during the association pattern period based on the retransmission counter satisfying a threshold.

[0212]

[0226] In some cases, 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 based on UE capabilities. In some cases, 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 based on random access procedure fallback capabilities. In some cases, 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 based on load balancing capabilities. In some cases, 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 based on multiplexing of contention-free random access and contention-based random access. In some cases, some of the SSBs mapped to the random access preambles of the two-step random access procedure are contiguous in the time domain, non-contiguous in the time domain, or both.

[0213]

[0227] The threshold component 1135 may determine that the number of SSBs meets a threshold. In some examples, the threshold component 1135 may determine that the number of SSBs is greater than a threshold, and some SSBs are mapped to the same RO among 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.

[0214]

[0228] 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 composed of different subsets of preamble sequences. In some examples, the sequence component 1140 determines that the preamble sequences in each subset of the subset of preamble sequences do not overlap. In some cases, the indices of the preamble sequences in each subset of the subset of preamble sequences are consecutive.

[0215]

[0229] In the beam component 1145, the transmit beams mapped to the random access preamble of 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 based on the spatial separation of the transmit beams mapped to the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure. In some examples, the beam component 1145 may perform a beam switch of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message. In some examples, the beam component 1145 may determine a change in the physical random access channel opportunity index of one or more ROs. In some examples, the beam component 1145 performs a beam switch of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message based on the change in the physical random access channel opportunity index.

[0216]

[0230] 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 the random access payload. In some examples, the beam component 1145 may perform a beam switch of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message based on the change in the physical uplink shared channel resource unit index associated with one or more PRUs of the random access payload. In some examples, the beam component 1145 may determine a change in a preamble sequence index of the random access preamble. In some examples, the beam component 1145 may perform a beam switch of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message based on the change in the random access preamble. In some examples, the beam component 1145 may determine to multiplex UCI in one or more of the random access preamble and the random access payload of the random access message.

[0217]

[0231] In some examples, the beam component 1145 may perform beam switching of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message based on multiplexing UCI in 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 may perform beam switching of one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message in conjunction with additional beam switching by the base station of one or more beams carrying multiple SSBs.

[0218]

[0232] 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, some SSBs have 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, the beam switch is enabled based on one or more of correlation, mapping, or trigger indication. In some cases, the trigger indication includes one or more of a preamble sequence, a reference signal, or UCI.

[0219]

[0233] The fallback component 1150 may perform a random access fallback procedure or a random access switch procedure from a two-step random access procedure to a four-step random access procedure. The performing the beam switch is based on the random access fallback procedure or the random access switch procedure. In some examples, the fallback component 1150 may identify a random access message of the four-step random access procedure based on the random access fallback procedure or the random access switch procedure, and the performing the beam switch is based on control signaling from the base station, where the beam switch includes a switch of one or more of the transmit beam and the receive beam. In some examples, the fallback component 1150 may identify a random access message of the four-step random access procedure based on the random access fallback procedure or the random access switch procedure, and the performing the beam switch is based on pre-configuration information including the association. In some cases, the control signaling includes DCI.

[0220]

[0234] 12 shows a diagram of a system 1200 including a device 1205 supporting beam association in a random access procedure according to an aspect of the present disclosure. The device 1205 may be or include examples of components of the device 905, the device 1005, or the UE 115 described herein. The device 1205 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including a UE communications manager 1210, an I / O controller 1215, a transceiver 1220, an antenna 1225, a memory 1230, and a processor 1240. These components may be in electronic communication via one or more buses (e.g., bus 1245).

[0221]

[0235] The UE communications manager 1210 described herein may be implemented to realize one or more potential advantages. One implementation may enable the device 1205 to conserve power and increase battery life by more efficiently communicating with the base station 105 (as shown in FIG. 1). Another implementation may facilitate low-latency communications at the device 1205 because beam association for random access messaging associated with different random access procedures may be improved.

[0222]

[0236] The UE communications manager 1210 may determine, based on the indication, a mapping between the multiple SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, and, based on the mapping, determine an association between one or more beams carrying the multiple SSBs 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 the base station.

[0223]

[0237] The I / O controller 1215 may manage input and output signals to the device 1205. The I / O controller 1215 may also manage peripheral devices not integrated into the device 1205. In some cases, the I / O controller 1215 may represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 1215 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In other cases, the I / O controller 1215 may represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, the I / O controller 1215 may be implemented as part of a processor. In some cases, a user may interact with the device 1205 through the I / O controller 1215 or through hardware components controlled by the I / O controller 1215.

[0224]

[0238] The transceiver 1220 may communicate bidirectionally via one or more antennas, wired links, 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 that modulates packets, provides the modulated packets to an antenna for transmission, and demodulates packets received from the antenna. In some cases, the wireless 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 transmitting or receiving multiple wireless transmissions.

[0225]

[0239] The memory 1230 may include RAM and ROM. The memory 1230 may store computer-readable, computer-executable code 1235 that includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1230 may include a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0226]

[0240] Code 1235 may include instructions implementing aspects of the present disclosure, including instructions supporting wireless communication. Code 1235 may be stored in a non-transitory computer-readable medium, such as system memory or other type of memory. In some cases, code 1235 may not be directly executable by processor 1240, but may (e.g., when compiled and executed) cause a computer to perform functions described herein.

[0227]

[0241] The processor 1240 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or some combination thereof). In some cases, the processor 1240 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 1240. The processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting beam correlation in a random access procedure).

[0228]

[0242] 13 shows a block diagram 1300 of a device 1305 supporting beam association in a random access procedure according to an aspect of the present disclosure. The device 1305 may be an example of an aspect of a base station 105 described herein. The device 1305 may include a receiver 1310, a base station communications 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).

[0229]

[0243] The receiver 1310 may receive information such as packets, user data, or control information related to various information channels (e.g., control channels, data channels, and information related to beam association in random access procedures, etc.). The information may be passed to other components of the device 1305. The receiver 1310 may be an example of an aspect of a transceiver 1620, as described with reference to FIG. 16. The receiver 1310 may utilize a single antenna or a set of antennas.

[0230]

[0244] The base station communications manager 1315 may determine a mapping between the multiple SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the multiple SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message, transmit information to the UE including one or more of the mapping between the multiple SSBs of the two-step random access procedure and the random access message and the association between the one or more beams carrying the multiple SSBs 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 the UE according to the mapping. The base station communications manager 1315 may be an example of an aspect of the base station communications manager 1610 described herein.

[0231]

[0245] The base station communications manager 1315 or its subcomponents may be implemented in hardware, in processor-executable code (e.g., software or firmware), or some combination thereof. If implemented in processor-executable code, the functions of the base station communications 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.

[0232]

[0246] The base station communications manager 1315 or its subcomponents may be physically located in various locations, including being distributed such that some of the functionality is implemented by one or more physical components at different physical locations. In some examples, the base station communications manager 1315 or its subcomponents may be separate and distinct components according to various aspects of the present disclosure. In some examples, the base station communications manager 1315 or its subcomponents may be combined with one or more other hardware components, including, but not limited to, an input / output (I / O) component, a transceiver, a network server, another computing device, one or more other components described in this disclosure, or combinations thereof according to various aspects of the present disclosure.

[0233]

[0247] 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. For example, the transmitter 1320 may be an example of an aspect of a transceiver 1620, such as described with reference to FIG. 16. The transmitter 1320 may utilize a single antenna or a set of antennas.

[0234]

[0248] 14 shows a block diagram 1400 of a device 1405 supporting beam association in a random access procedure according to an aspect of the present disclosure. The device 1405 may be an example of an aspect of the device 1305 or base station 105 described herein. The device 1405 may include a receiver 1410, a base station communications 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).

[0235]

[0249] The receiver 1410 may receive information such as packets, user data, or control information related to various information channels (e.g., control channels, data channels, and information related to beam association in random access procedures, etc.). The information may be passed to other components of the device 1405. The receiver 1410 may be an example of an aspect of a transceiver 1620, as described with reference to FIG. 16. The receiver 1410 may utilize a single antenna or a set of antennas.

[0236]

[0250] The base station communications manager 1415 may be an example of an aspect of the base station communications manager 1315, as described herein. The base station communications manager 1415 may include a mapping component 1420, an information component 1425, and an access component 1430. The base station communications manager 1415 may be an example of an aspect of the base station communications manager 1610, as described herein.

[0237]

[0251] The mapping component 1420 may determine a mapping between the multiple SSBs of the two-step random access procedure and a random access message, where 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 multiple SSBs 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 transmit information to the UE including one or more of the mapping between the multiple SSBs of the two-step random access procedure and the random access message, and the association between the one or more beams carrying the multiple SSBs 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 the two-step random access procedure with the UE according to the mapping.

[0238]

[0252] The transmitter 1435 may transmit signals generated by other components of the device 1405. In some examples, the transmitter 1435 may be co-located with the receiver 1410 in a transceiver module. For example, the transmitter 1435 may be an example of an aspect of a transceiver 1620, as described with reference to FIG. 16. The transmitter 1435 may utilize a single antenna or a set of antennas.

[0239]

[0253] 15 illustrates a block diagram 1500 of a base station communications manager 1505 supporting beam association in a random access procedure according to an aspect of the present disclosure. The base station communications manager 1505 may be an example of an aspect of the base station communications manager 1315, the base station communications manager 1415, or the base station communications manager 1610 described herein. The base station communications manager 1505 may 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 fallback component 1550. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0240]

[0254] The mapping component 1510 may determine a mapping between multiple SSBs of a two-step random access procedure and a random access message, where 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 multiple SSBs 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 multiple SSBs to one or more ROs of the random access preamble and one or more PRUs of the random access payload over a PRACH configuration period of an association pattern period of the two-step random access procedure.

[0241]

[0255] The mapping component 1510 may determine a mapping between one or more PRUs of the random access payload that share time / frequency resources and an SSB of the plurality of SSBs or a portion of the SSBs of the plurality of SSBs, where the portion of the SSBs of the plurality of SSBs are grouped. In some examples, the mapping component 1510 may map one or more PRUs of the random access payload that share time / frequency resources to an SSB of the plurality of SSBs based on analog beamforming capabilities. In some cases, the mapping component 1510 may map one or more PRUs of the random access payload that share time / frequency resources to a portion of the SSBs of the plurality of SSBs based on digital beamforming capabilities. In some cases, the random access preamble and the random access payload of the random access message are associated with different SSBs of the plurality of SSBs based on the duration of a guard period associated with the random access preamble and a gap duration between the random access preamble and the random access payload.

[0242]

[0256] The information component 1515 may transmit information to the UE including one or more of: a mapping between the plurality of SSBs of the two-step random access procedure and the random access message; and an association between one or more beams carrying the plurality of SSBs 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 according to the mapping.

[0243]

[0257] The signaling component 1525 may transmit signaling including information including one or more of: a mapping between the plurality of SSBs of the two-step random access procedure and the random access message; and an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. In some cases, the signaling includes system information signaling. In some cases, the signaling includes RRC signaling.

[0244]

[0258] The resource component 1530 may determine that one or more PRUs of the random access payload 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 of the number of SSBs. In some cases, some of the number of SSBs mapped to the random access preamble of the two-step random access procedure are one or more of contiguous in the time domain and non-contiguous in the time domain.

[0245]

[0259] The threshold component 1535 may determine that the number of SSBs meets a threshold. In some examples, the threshold component 1535 may determine that the number of SSBs is greater than a threshold, and some SSBs are mapped to the same RO among 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.

[0246]

[0260] The sequence component 1540 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 with different subsets of preamble sequences. 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.

[0247]

[0261] The beam component 1545 may perform beam switching of one or more additional beams carrying the random access preamble or the random access payload of the random access message, or both, where the one or more additional beams comprise receive beams. In some examples, the beam component 1545 may perform beam switching of one or more additional beams carrying the random access preamble or the random access payload of the random access message in conjunction with beam switching of one or more beams carrying multiple SSBs, where the one or more additional beams comprise receive beams, and the one or more beams carrying the multiple SSBs comprise transmit beams. In some cases, some SSBs have 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.

[0248]

[0262] The fallback component 1550 may perform a random access fallback procedure or a random access switch procedure from a two-step random access procedure to a four-step random access procedure, and performing the beam switch is based on the random access fallback procedure or the random access switch procedure. In some examples, the fallback component 1550 may identify a random access message of the four-step random access procedure based on the random access fallback procedure or the random access switch procedure. In some examples, the fallback component 1550 may send control signaling to the UE, and performing the beam switch is based on the control signaling, and the beam switch includes switching one or more of a transmit beam and a receive beam.

[0249]

[0263] In some cases, the control signaling includes a DCI.

[0250]

[0264] 16 shows a diagram of a system 1600 including a device 1605 supporting beam association in a random access procedure according to an aspect of the disclosure. The device 1605 may be an example of or include components of the device 1305, device 1405, or base station 105 described herein. The device 1605 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including a base station communications manager 1610, a network communications manager 1615, a transceiver 1620, an antenna 1625, a memory 1630, a processor 1640, and an inter-station communications manager 1645. These components may be in electronic communication via one or more buses (e.g., bus 1650).

[0251]

[0265] The base station communications manager 1610 may determine a mapping between the multiple SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the multiple SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message, transmit information to the UE including one or more of the mapping between the multiple SSBs of the two-step random access procedure and the association between one or more beams carrying the multiple SSBs 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 the UE according to the mapping.

[0252]

[0266] The network communications manager 1615 may manage communications with a core network (e.g., over one or more wired backhaul links). For example, the network communications manager 1615 may manage the forwarding of data communications for client devices, such as one or more UEs 115.

[0253]

[0267] The transceiver 1620 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 1620 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1620 may also include a modem that modulates packets, provides the modulated packets to an antenna for transmission, and demodulates packets received from the antenna. In some cases, the wireless device 1605 may include a single antenna 1625. However, in some cases, the device 1605 may have more than one antenna 1625, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0254]

[0268] Memory 1630 may include RAM, ROM, or a combination thereof. Memory 1630 may store computer-readable code 1635 containing instructions that, when executed by a processor (e.g., processor 1640), cause the device to perform various functions described herein. In some cases, memory 1630 may include a BIOS, which may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0255]

[0269] Code 1635 may include instructions implementing aspects of the present disclosure, including instructions supporting wireless communication. Code 1635 may be stored in a non-transitory computer-readable medium, such as system memory or other type of memory. In some cases, code 1635 may not be directly executable by processor 1640, but may (e.g., when compiled and executed) cause a computer to perform functions described herein.

[0256]

[0270] The 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 some combination thereof). In some cases, the processor 1640 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into the processor 1640. The processor 1640 is configured to execute computer-readable instructions stored in a memory (e.g., memory 1630) and may cause the device 1605 to perform various functions (e.g., functions or tasks supporting beam correlation in a random access procedure).

[0257]

[0271] The inter-station communications manager 1645 may manage communications with other base stations 105 and may include a controller or scheduler that cooperates with the other base stations 105 to control communications with the UE 115. For example, the inter-station communications manager 1645 may coordinate scheduling of transmissions to the UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-station communications manager 1645 may provide an X2 interface within the LTE / LTE-A wireless communications network technology to provide communications between the base stations 105.

[0258]

[0272] FIG. 17 shows a flowchart illustrating a method 1700 for supporting beam association in a random access procedure according to an aspect of the present disclosure. The operations of method 1700 may be implemented by the UE 115 or components thereof, as described herein. For example, the operations of method 1700 may be performed by a communications manager, as described with reference to FIGS. 9-12. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use special-purpose hardware to perform aspects of the functions described below.

[0259]

[0273] At 1705, the UE may determine, based on the indication, a mapping between the plurality of SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload. The operations of 1705 may be performed according to methods described herein. In some examples, aspects of the operations of 1705 may be performed by a mapping component, such as those described with reference to FIGS. 9-12.

[0260]

[0274] At 1710, the UE may determine, based on the mapping, an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The operations of 1710 may be performed according to methods described herein. In some examples, aspects of the operations of 1710 may be performed by an association component, such as those described with reference to FIGS. 9-12.

[0261]

[0275] At 1715, the UE may perform a two-step random access procedure with the base station. The operations of 1715 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1715 may be performed by an access component, such as those described with reference to FIGS. 9-12.

[0262]

[0276] FIG. 18 shows a flowchart illustrating a method 1800 for supporting beam association in a random access procedure according to an aspect of the present disclosure. The operations of method 1800 may be implemented by the UE 115 or components thereof, as described herein. For example, the operations of method 1800 may be performed by a communications manager, as described with reference to FIGS. 9-12. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform functions described below. Additionally or alternatively, the UE may use special-purpose hardware to perform aspects of the functions described below.

[0263]

[0277] At 1805, the UE may determine, based on the indication, a mapping between the plurality of SSBs of the two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload. The operations of 1805 may be performed according to methods described herein. In some examples, aspects of the operations of 1805 may be performed by a mapping component, such as those described with reference to FIGS. 9-12.

[0264]

[0278] At 1810, the UE may determine, based on the mapping, an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The operations of 1810 may be performed according to methods described herein. In some examples, aspects of the operations of 1810 may be performed by an association component, such as those described with reference to FIGS. 9-12.

[0265]

[0279] At 1815, the UE may map resources of the multiple SSBs to one or more ROs of the random access preamble and one or more PRUs of the random access payload over a PRACH configuration period of an association pattern period of the two-step random access procedure. The operations of 1815 may be performed according to methods described herein. In some examples, aspects of the operations of 1815 may be performed by a mapping component, such as those described with reference to FIGS. 9-12.

[0266]

[0280] At 1820, the UE may perform a two-step random access procedure with the base station. The operations of 1820 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1820 may be performed by an access component, such as those described with reference to FIGS. 9-12.

[0267]

[0281] FIG. 19 shows a flowchart illustrating a method 1900 for supporting beam association in a random access procedure according to an aspect of the present disclosure. The operations of method 1900 may be implemented by a base station 105 or components thereof, as described herein. For example, the operations of method 1900 may be performed by a communications manager, such as those described with reference to FIGS. 13-16. In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use special-purpose hardware to perform aspects of the functions described below.

[0268]

[0282] At 1905, the base station may determine a mapping between a plurality of SSBs of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of SSBs 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 methods described herein. In some examples, aspects of the operations of 1905 may be performed by a mapping component, such as those described with reference to FIGS. 13-16.

[0269]

[0283] In 1910, the base station may transmit information to the UE including one or more of: a mapping between the plurality of SSBs of the two-step random access procedure and the random access message; and an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The operations of 1910 may be performed according to methods described herein. In some examples, aspects of the operations of 1910 may be performed by information components such as those described with reference to FIGS. 13-16.

[0270]

[0284] At 1915, the base station may perform a two-step random access procedure with the UE in accordance with the mapping. The operations of 1915 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1915 may be performed by an access component, such as those described with reference to FIGS. 13-16.

[0271]

[0285] FIG. 20 shows a flowchart illustrating a method 2000 for supporting beam association in a random access procedure in accordance with an aspect of the present disclosure. The operations of method 2000 may be implemented by a UE 115 or components thereof, as described herein. For example, the operations of method 2000 may be performed by a communications manager, as described with reference to FIGS. 13-16. In some examples, a base station may execute a set of instructions to control functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use special purpose hardware to perform aspects of the functions described below.

[0272]

[0286] In 2005, the base station may determine a mapping between a plurality of SSBs of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload, the mapping including an association between one or more beams carrying the plurality of SSBs 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 methods described herein. In some examples, aspects of the operations of 2005 may be performed by a mapping component, such as those described with reference to FIGS. 13-16.

[0273]

[0287] In 2010, the base station may transmit information to the UE including one or more of: a mapping between the plurality of SSBs of the two-step random access procedure and the random access message; and an association between one or more beams carrying the plurality of SSBs and one or more additional beams carrying the random access preamble and the random access payload of the random access message. The operations of 2010 may be performed according to methods described herein. In some examples, aspects of the operations of 2010 may be performed by information components such as those described with reference to FIGS. 13-16.

[0274]

[0288] In 2015, the base station may map resources of the multiple SSBs to one or more ROs of the random access preamble and one or more PRUs of the random access payload over a PRACH configuration period of an association pattern period of the two-step random access procedure. The operations of 2015 may be performed according to methods described herein. In some examples, aspects of the operations of 2015 may be performed by a mapping component, such as those described with reference to Figures 13-16.

[0275]

[0289] At 2020, the base station may perform a two-step random access procedure with the UE in accordance with the mapping. The operations of 2020 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 2020 may be performed by an access component, such as those described with reference to FIGS. 13-16.

[0276]

[0290] 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 of the methods may be combined.

[0277]

[0291] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system are described for illustrative purposes and LTE, LTE-A, LTE-A Pro, or NR terminology may be used throughout much of the description, the techniques described herein are 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, as well as other systems and radio technologies not explicitly mentioned herein.

[0278]

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

[0279]

[0293] The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in alternative embodiments, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with the core of a DSP, or any other such configuration).

[0280]

[0294] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. The features implementing the functions may also be physically located in various locations, including being distributed so that portions of the functions are implemented in different physical locations.

[0281]

[0295] Computer-readable media includes both non-transitory computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. Non-transitory storage media may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may comprise RAM, ROM, Electrically Erasable Programmable Read Only Memory (EEPROM), Compact Disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer or general-purpose or special-purpose processor. Furthermore, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. As used herein, disk and disc include CDs, laser discs, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray discs, although disks typically reproduce data magnetically while discs reproduce data optically with a laser. Combinations of the above are also included within the scope of computer-readable media.

[0282]

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

[0283]

[0297] In the accompanying figures, similar components or features may have the same reference label. Additionally, various components of the same type may be distinguished by the reference label and by a second label that distinguishes between the similar components. When only a first reference label is used herein, the description is applicable to any one of the similar components with the first reference label, or any other subsequent reference label, regardless of the second reference label.

[0284]

[0298] The description set forth herein, with reference to the accompanying drawings, describes exemplary configurations and does not represent every example that may be implemented or fall within the scope of the claims. As used herein, the term "exemplary" means "serving as an example, instance, or illustration," rather than the term "preferred" or "advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0285]

[0299] The description herein is provided to enable any person skilled in the art to make or use the disclosure. Various modifications of the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The inventions described in the claims of the present application as originally filed are set forth below. [C1] 1. A method for wireless communication in a user equipment, comprising: determining, based at least in part on the indication, a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload; determining, based at least in part on the mapping, an association between one or more beams carrying the plurality of synchronization signal blocks 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. [C2] The method of C1 further includes mapping resources of the plurality of synchronization signal blocks 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 over a physical random access channel configuration period of an association pattern period of the two-step random access procedure. [C3] The method of C2 further includes determining the association pattern duration of the two-step random access procedure based at least in part on a second indication, wherein the association pattern duration of the two-step random access procedure is based at least in part on a factor value of an association pattern duration of a four-step random access procedure, and the factor value includes an integer value within a range configured by the network. [C4] determining, over an additional physical random access channel configuration period of a second association pattern period of the two-step random access procedure, a second association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of C3, wherein the second association over the second association pattern period of the two-step random access procedure is different from the association over the association pattern period of the two-step random access procedure. [C5] The method of C1 further includes receiving signaling from the base station including the indication including an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message, wherein the signaling includes system information signaling or radio resource control signaling, or both. [C6] determining, based at least in part on a physical random access channel opportunity index of the one or more physical random access channel opportunities, an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of C1, wherein the indication includes the physical random access channel opportunity index. [C7] determining, based at least in part on a preamble sequence of the random access preamble, an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of C1, wherein the indication includes the preamble sequence. [C8] determining, based at least in part on physical uplink shared channel resource unit indexes associated with the one or more physical uplink shared channel resource units of the random access payload, an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of C1, wherein the indication includes the physical uplink shared channel resource unit index. [C9] determining, based at least in part on multiplexing uplink control information in one or more of the random access preamble and the random access payload of the random access message, an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of claim C1, wherein the indication includes multiplexing the uplink control information. [C10] The method of claim C1, wherein the random access preamble and the random access payload of the random access message are associated with different synchronization signal blocks among the plurality of synchronization signal blocks based at least in part on the duration of a guard period associated with the access preamble and a gap duration between the random access preamble and the random access payload. [C11] determining that one or more physical uplink shared channel resource units of the random access payload share one or more of a time resource and a frequency resource; 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 resource and the frequency resource and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks; The method of C1, wherein some of the synchronization signal blocks of the plurality of synchronization signal blocks are grouped. [C12] 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 resource and the frequency resource and the synchronization signal block of the plurality of synchronization signal blocks or a portion of the synchronization signal block of the plurality of synchronization signal blocks, The method of C11 includes 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 synchronization signal blocks of the plurality of synchronization signal blocks based at least in part on analog beamforming capabilities. [C13] 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 resource and the frequency resource and the synchronization signal block of the plurality of synchronization signal blocks or a portion of the synchronization signal block of the plurality of synchronization signal blocks, The method of C11 includes 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 a portion of the synchronization signal blocks among the plurality of synchronization signal blocks based at least in part on digital beamforming capability. [C14] The method of C1 further includes determining, based at least in part on UE capabilities, random access procedure fallback capabilities, load balancing capabilities, or multiplexing of connection-free random access and contention-based random access, or any combination thereof, that the one or more physical random access channel opportunities of the random access preamble are shared with one or more additional random access preambles of a four-step random access procedure. [C15] determining whether a number of synchronization signal blocks meets a threshold; The method of C1 further includes determining 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 with different subsets of preamble sequences. [C16] The method of C15, wherein indices of the preamble sequences in each subset of the preamble sequences are consecutive. [C17] The method of C15, wherein the preamble sequences in each subset of said preamble sequences are non-overlapping. [C18] The method of C15, 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 the same receiving beam. [C19] determining that the number of synchronization signal blocks is greater than a threshold; A method as described in C1, in which some synchronization signal blocks are mapped to the same physical random access channel opportunity among one or more physical random access channel opportunities 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. [C20] The method of C19, wherein the several synchronization signal blocks have different transmit beams. [C21] The method of C19, 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. [C22] A method according to C21, wherein some of the synchronization signal blocks mapped to the random access preamble of the two-step random access procedure are one or more of contiguous in the time domain or not contiguous in the time domain. [C23] A method as described in C21, wherein the transmit beams mapped to the random access preamble of 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 based at least in part on the spatial separation of the transmit beams mapped to the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure. [C24] The method of C21, 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 receive beams. [C25] performing the two-step random access procedure transmitting the random access message of the two-step random access procedure to the base station during an association pattern period; and retransmitting the random access message of the two-step random access procedure during the association pattern period based at least in part on a retransmission counter being less than a threshold. [C26] The method of C25, further comprising performing a beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message. [C27] determining a change in a physical random access channel opportunity index of the one or more physical random access channel opportunities; The method of C26, wherein performing the beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message is based at least in part on a change in the physical random access channel opportunity index. [C28] 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; The method of C26, wherein performing the beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message is based at least in part on a 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. [C29] determining a change in a preamble sequence index of the random access preamble; The method of C26, wherein performing the beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message is based at least in part on a change in the random access preamble. [C30] determining to multiplex uplink control information in one or more of the random access preamble and the random access payload of the random access message; The method of C26, wherein performing the beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message is based at least in part on multiplexing the uplink control information in one or more of the random access preamble and the random access payload of the random access message. [C31] The method of C26 further includes performing the beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message in conjunction with the additional beam switch by the base station of the one or more beams carrying the plurality of synchronization signal blocks. [C32] The method of C26, wherein the beam switch is enabled based at least in part on one or more of the association, the mapping, or a trigger indication including one or more of a preamble sequence, a reference signal, or uplink control information. [C33] performing a random access fallback procedure or a random access switch procedure from the two-step random access procedure to a four-step random access procedure; The method of C26, wherein performing the beam switch is based at least in part on the random access fallback procedure or the random access switch procedure. [C34] further comprising identifying a random access message of the four-step random access procedure based at least in part on the random access fallback procedure or the random access switch procedure; The method of C33, wherein performing the beam switch is based at least in part on control signaling including downlink control information from the base station, and the beam switch includes switching one or more of a transmit beam and a receive beam. [C35] further comprising identifying a random access message of the four-step random access procedure based at least in part on the random access fallback procedure or the random access switch procedure; The method of C33, wherein performing the beam switch is based at least in part on pre-configuration information that includes the association. [C36] The method of C25, wherein the resources for transmitting the random access message of the two-step random access procedure to the base station during an association pattern period are the same resources for retransmitting the random access message of the two-step random access procedure during the association pattern period based at least in part on the retransmission counter satisfying the threshold. [C37] The method of C25, wherein resources for transmitting the random access message of the two-step random access procedure to the base station during an association pattern period are different from resources for retransmitting the random access message of the two-step random access procedure during the association pattern period based at least in part on the retransmission counter satisfying the threshold. [C38] 1. A method for wireless communication in a base station, comprising: determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; transmitting to a user equipment information including one or more of: a mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure; and an association between the one or more beams carrying the plurality of synchronization signal blocks 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. [C39] The method of C38 further comprises mapping resources of the plurality of synchronization signal blocks 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 over a physical random access channel configuration period of an association pattern period of the two-step random access procedure. [C40] Transmitting the information to the user equipment includes: transmitting signaling including the information including one or more of: a mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure; and an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; The method of C38, wherein the signaling includes system information signaling or radio resource control signaling, or both. [C41] The method of C38, wherein the random access preamble and the random access payload of the random access message are associated with different synchronization signal blocks among the plurality of synchronization signal blocks based at least in part on the duration of a guard period associated with the random access preamble and a gap duration between the random access preamble and the random access payload. [C42] determining that one or more physical uplink shared channel resource units of the random access payload share one or more of a time resource and a frequency resource; 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 resource and the frequency resource and a synchronization signal block of the plurality of synchronization signal blocks or a portion of a synchronization signal block of the plurality of synchronization signal blocks; The method of C38, wherein some of the synchronization signal blocks of the plurality of synchronization signal blocks are grouped. [C43] 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 resource and the frequency resource and the synchronization signal block of the plurality of synchronization signal blocks or a portion of the synchronization signal block of the synchronization signal blocks, The method of C42 includes 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 synchronization signal blocks of the plurality of synchronization signal blocks based at least in part on analog beamforming capabilities. [C44] determining a mapping between the one or more physical uplink shared channel resource units of the random access payload that share the time resource and the synchronization signal block of the plurality of synchronization signal blocks or a portion of the synchronization signal block of the synchronization signal blocks, The method of C42 includes mapping the one or more physical uplink shared channel resource units of the random access payload that share the time resource to a portion of the synchronization signal blocks among the plurality of synchronization signal blocks based at least in part on digital beamforming capabilities. [C45] determining that the number of synchronization signal blocks meets a threshold; The method of C38 further includes determining 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 have the same receive beam and are configured with different subsets of preamble sequences. [C46] determining that the number of synchronization signal blocks is greater than a threshold; The method of C38, wherein several synchronization signal blocks are mapped to the same physical random access channel opportunity of one or more physical random access channel opportunities 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. [C47] The method of C46, ​​wherein the several synchronization signal blocks have different transmit beams. [C48] The method of C46, ​​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. [C49] A method according to C48, wherein some of the synchronization signal blocks mapped to the random access preamble of the two-step random access procedure are one or more of contiguous in the time domain and / or not contiguous in the time domain. [C50] The method of C48, 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 receive beams. [C51] performing a beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message; The method of C38, wherein the one or more additional beams comprises a receive beam. [C52] performing a beam switch of the one or more additional beams carrying the random access preamble or the random access payload, or both, of the random access message in conjunction with the beam switch of the one or more beams carrying the plurality of synchronization signal blocks; The method of C38, wherein the one or more additional beams comprise a receive beam and the one or more beams carrying the plurality of synchronization signal blocks comprise a transmit beam. [C53] performing a random access fallback procedure or a random access switch procedure from the two-step random access procedure to a four-step random access procedure; The method of C52, wherein performing the beam switch is based at least in part on the random access fallback procedure or the random access switch procedure. [C54] identifying a random access message of the four-step random access procedure based at least in part on the random access fallback procedure or the random access switch procedure; transmitting control signaling to the user equipment, the control signaling including downlink control information; The method of C53, wherein performing the beam switch is based at least in part on the control signaling, and the beam switch includes switching one or more of a transmit beam and a receive beam. [C55] 1. An apparatus for wireless communication, comprising: a processor; a memory coupled to the processor; instructions stored in the memory; The instructions may cause the device to: determining, based at least in part on the indication, a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload; determining, based at least in part on the mapping, an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; An apparatus executable by the processor to cause the two-step random access procedure with a base station. [C56] 1. An apparatus for wireless communication, comprising: a processor; a memory coupled to the processor; instructions stored in the memory; The instructions may cause the device to: determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; causing a user equipment to transmit information including one or more of: a mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure; and an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; An apparatus executable by the processor to cause the two-step random access procedure with the user equipment to be performed in accordance with the mapping. [C57] 1. An apparatus for wireless communication, comprising: means for determining, based at least in part on the indication, a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload; means for determining, based at least in part on the mapping, an association between one or more beams carrying the plurality of synchronization signal blocks 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. [C58] 1. An apparatus for wireless communication, comprising: means for determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; means for transmitting to a user equipment information including one or more of: a mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure; and an association between the one or more beams carrying the plurality of synchronization signal blocks and the 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 the user equipment in accordance with the mapping. [C59] A non-transitory computer-readable medium storing code for wireless communication in a user equipment, comprising: The code determining, based at least in part on the indication, a mapping between a plurality of synchronization signal blocks of a two-step random access procedure and a random access message, the random access message including a random access preamble and a random access payload; determining, based at least in part on the mapping, an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; A non-transitory computer-readable medium containing instructions executable by a processor to cause said two-step random access procedure with a base station. [C60] A non-transitory computer-readable medium storing code for wireless communication at a base station, comprising: The code determining a mapping between a plurality of synchronization signal blocks 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 mapping including an association between one or more beams carrying the plurality of synchronization signal blocks and one or more additional beams carrying the random access preamble and the random access payload of the random access message; causing a user equipment to transmit information including one or more of: a mapping between the plurality of synchronization signal blocks and the random access message of the two-step random access procedure; and an association between the one or more beams carrying the plurality of synchronization signal blocks and the one or more additional beams carrying the random access preamble and the random access payload of the random access message; a non-transitory computer-readable medium comprising instructions executable by a processor to cause the two-step random access procedure with the user equipment in accordance with the mapping;

Claims

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

2. determining a second association of beams between the synchronization signal block and the set of PRACH opportunities based at least in part on a second association pattern period of the two-step random access procedure; mapping resources of the synchronization signal block to the one or more physical uplink shared channel resource units and the set of PRACH opportunities over additional PRACH configuration periods of the second association pattern period of the two-step random access procedure; The method of claim 1 , comprising:

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

4. receiving the configuration from the network entity further comprises receiving signaling from the network entity including the configuration; The method of claim 1 , wherein the signaling comprises system information signaling, radio resource control signaling, or both.

5. determining the association between the synchronization signal block and the set of PRACH opportunities based at least in part on a PRACH opportunity index of the one or more PRACH opportunities; the configuration comprises the PRACH opportunity index. The method of claim 1.

6. determining the association between the synchronization signal block and the set of PRACH opportunities based at least in part on a preamble sequence of a random access preamble; the configuration comprises the preamble sequence; The method of claim 1.

7. determining the association between the synchronization signal block and the set of PRACH opportunities 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; the configuration comprises the physical uplink shared channel resource unit index; The method of claim 1.

8. 2. The method of claim 1, wherein the set of PRACH opportunities and the one or more physical uplink shared channel resource units 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 units.

9. The method of claim 8 , wherein a number of symbols between the set of PRACH opportunities and the one or more physical uplink shared channel resource units is configured by the network entity.

10. determining that the one or more physical uplink shared channel resource units share one or more of a time resource and a frequency resource; determining a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resource and the frequency resource and one or some of the synchronization signal blocks; Furthermore, The method of claim 1 , wherein the some of the synchronization signal blocks are grouped.

11. determining a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resource and the frequency resource and the one synchronization signal block or the part of the synchronization signal blocks; 11. The method of claim 10, comprising mapping the one or more physical uplink shared channel resource units that share one of the time resources and the frequency resources to the one of the synchronization signal blocks based at least in part on analog beamforming capabilities.

12. determining a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resource and the frequency resource and the one synchronization signal block or the part of the synchronization signal blocks; 11. The method of claim 10, comprising mapping the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources to the portion of the synchronization signal blocks based at least in part on digital beamforming capabilities.

13. determining that the one or more PRACH opportunities of the two-step random access procedure are shared with a 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; The method of claim 1 further comprising:

14. determining that a number of synchronization signal blocks meets a threshold; determining 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 composed of different subsets of preamble sequences; The method of claim 1 further comprising:

15. 15. The method of claim 14, wherein the indices of the preamble sequences in each subset of the subsets of preamble sequences are consecutive.

16. 15. The method of claim 14, wherein the indices of the preamble sequences in each subset of the subsets of preamble sequences are non-overlapping.

17. determining that the number of synchronization signal blocks is greater than a threshold; 2. The method of claim 1, wherein some synchronization signal blocks are mapped to the same PRACH opportunity among the one or more PRACH opportunities shared between a random access preamble of the two-step random access procedure and a random access message of a four-step random access procedure.

18. 20. The method of claim 17, wherein the several synchronization signal blocks have different transmit beams.

19. 18. The method of 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 of the number of synchronization signal blocks.

20. 20. The method of claim 19, wherein some of the several synchronization signal blocks mapped to the random access preamble of the two-step random access procedure are one or more of: contiguous in the time domain, or non-contiguous in the time domain.

21. 20. The method of claim 19, wherein transmit beams mapped to the random access preamble of 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 based at least in part on spatial separation of the transmit beams mapped to the random access preamble of the two-step random access procedure and the random access message of the four-step random access procedure.

22. 20. The method of 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 receive beams.

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

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

25. 24. The method of claim 23, wherein the set of PRACH opportunities and the one or more physical uplink shared channel resource units 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 units.

26. determining that the one or more physical uplink shared channel resource units share one or more of a time resource and a frequency resource; determining a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resource and the frequency resource and one or some of the synchronization signal blocks; Furthermore, 24. The method of claim 23, wherein the some of the synchronization signal blocks are grouped.

27. determining a mapping between the one or more physical uplink shared channel resource units that share one or more of the time resource and the frequency resource and the one synchronization signal block or the part of the synchronization signal blocks; 27. The method of claim 26, comprising mapping the one or more physical uplink shared channel resource units that share one or more of the time resources and the frequency resources to the one of the synchronization signal blocks based at least in part on analog beamforming capabilities.

28. 1. An apparatus for wireless communication, comprising: one or more processors; one or more memories coupled to the one or more processors; instructions stored in the one or more memories; The instructions may cause the device to: receiving, from a network entity, a configuration of physical random access channel (PRACH) opportunities for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single PRACH opportunity of the PRACH and a number of contention-based preambles for each of the synchronization signal blocks for each valid PRACH opportunity of the PRACH opportunities; determining a beam association between the synchronization signal block and a set of PRACH opportunities based at least in part on the configuration and an association pattern period of the two-step random access procedure, the association pattern period being based at least in part on a finite range / time domain configured by the network entity; mapping resources of the synchronization signal block to one or more physical uplink shared channel resource units and the set of PRACH opportunities over a PRACH configuration period of the association pattern period of the two-step random access procedure; performing the two-step random access procedure with the network entity based at least in part on the mapping; and Executable by the one or more processors, individually or collectively, to cause the apparatus to perform

29. The instructions may further cause the device to: determining a second association of beams between the synchronization signal block and the set of PRACH opportunities based at least in part on a second association pattern period of the two-step random access procedure; mapping resources of the synchronization signal block to the one or more physical uplink shared channel resource units and the set of PRACH opportunities over additional PRACH configuration periods of the second association pattern period of the two-step random access procedure; 30. The apparatus of claim 28, wherein the one or more processors are individually or collectively executable to cause:

30. 1. An apparatus for wireless communication, comprising: one or more processors; one or more memories coupled to the one or more processors; instructions stored in the one or more memories; The instructions may cause the device to: outputting a configuration of physical random access channel (PRACH) opportunities for a two-step random access procedure, the configuration indicating a number of synchronization signal blocks associated with a single PRACH opportunity of the PRACHs and a number of contention-based preambles for each of the synchronization signal blocks for each valid PRACH opportunity of the PRACH opportunities; determining a beam association between the synchronization signal block and a set of PRACH opportunities based at least in part on the configuration and an association pattern period of the two-step random access procedure, the association pattern period being based at least in part on a finite range / time domain configured by a network entity; mapping resources of the synchronization signal block to one or more physical uplink shared channel resource units and the set of PRACH opportunities over a PRACH configuration period of the association pattern period of the two-step random access procedure; performing the two-step random access procedure with a user equipment based at least in part on the mapping; and Executable by the one or more processors, individually or collectively, to cause the apparatus to perform

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