Conflict reduction for random access procedures

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may transmit a random access preamble according to a cyclic shift from a first set of cyclic shifts associated with a cyclic shift step length that is less than a round trip time (RTT) of a serving cell of the UE. The UE may generate a first set of cyclic shifts based on a second set of cyclic shifts and a set of cyclic shift offsets associated with an offset step length less than the RTT. If the network entity detects a conflict between the random access preamble and another random access preamble, the network entity may send a conflict resolution message indicating resources for the UE to retransmit the random access preamble. Alternatively, the network entity may continue the random access procedure by sending a random access response message to the UE.

Description

Cross-references

[0001] This patent application claims priority to U.S. Patent Application No. 18 / 466,239, filed September 13, 2023, entitled “COLLISIONREDUCTION FOR RANDOM ACCESS PROCEDURES”, which is assigned to the assignee of this application and is expressly incorporated herein by reference. Technical Field

[0002] The following discussion pertains to wireless communications, including collision reduction for random access procedures. Background Technology

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, message sending and receiving, broadcasting, and so on. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth-generation (4G) systems (such as Long Term Evolution (LTE) systems, LTE-A Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), or Discrete Fourier Transform Extended Orthogonal Frequency Division Multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations, each supporting wireless communication of communication devices, which may be referred to as User Equipment (UE).

[0004] In a wireless communication system, a UE can establish a connection with a network entity using a random access procedure. The UE initiates the random access procedure by sending a first random access message (e.g., a preamble) to the network entity via the Physical Random Access Channel (PRACH). The network entity and the UE can exchange one or more additional random access messages to establish a connection. Summary of the Invention

[0005] The described techniques relate to methods, systems, devices, and apparatuses that support improvements in collision reduction for random access procedures. For example, the described techniques enable a UE to transmit a random access preamble based on cyclic shifts from a first set of cyclic shifts associated with a cyclic shift step size smaller than the round-trip time (RTT) (e.g., maximum RTT) of the cell associated with the UE. Cyclic shift offsets enable a receiving network entity to distinguish random access preambles communicated by multiple different UEs. In some examples, the UE may generate the first set of cyclic shifts based on a second set of cyclic shifts (e.g., nominal cyclic shifts with a second step size greater than or equal to the RTT) and a set of cyclic shift offsets, wherein this set of cyclic shift offsets is associated with an offset step size smaller than the RTT of the UE's serving cell (e.g., having a regular or consistent offset step size). Additionally or alternatively, the cyclic shift step size of the first set of cyclic shifts may be a consistent (e.g., regular) step size smaller than the RTT.

[0006] The network entity associated with the serving cell can receive a random access preamble and can send a message to the UE in response to the random access preamble. For example, if the network entity detects a collision between the random access preamble and another random access preamble from a second UE, the network entity can send a collision resolution message indicating the resources for the UE to retransmit the random access preamble. Alternatively, if the network entity does not detect a collision, the network entity can continue the random access procedure by sending a Random Access Response (RAR) message (also known as msg2 or msgB) to the UE.

[0007] A method for wireless communication by a UE is described. The method may include: receiving a control message indicating a first set of cyclic shifts for transmitting a random access message (e.g., a RACH message) including a random access preamble; and transmitting the random access message according to cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the UE's serving cell.

[0008] A UE for wireless communication is described. The UE may include: one or more memories storing processor-executable code; and one or more processors coupled to the one or more memories. The one or more processors may be able to operate individually or jointly to execute code such that the UE: receives a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble; and transmits the random access message according to cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the UE's serving cell.

[0009] Another UE for wireless communication is described. The UE may include: means for receiving a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble; and means for transmitting the random access message according to cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the UE's serving cell.

[0010] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: receive a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble; and transmit the random access message according to cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the serving cell of the UE.

[0011] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, receiving a control message indicating a first set of cyclic shifts may include operations, features, components, or instructions for: receiving a control message indicating a second set of cyclic shifts and a set of cyclic shift offsets including a first cyclic shift step size; and generating the first set of cyclic shifts based on the second set of cyclic shifts and the set of cyclic shift offsets.

[0012] The methods described herein, some examples of UEs and nontransitory computer-readable media may also include operations, features, components or instructions for selecting cyclic shifts from a first set of cyclic shifts, the first set of cyclic shifts having a consistent cyclic shift step size that may be less than the RTT.

[0013] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, control messages indicate a cyclic shift monitoring range that may be based on RTT, and the methods, apparatus, and nontransitory computer-readable media may also include operations, features, components, or instructions for: receiving a first response message indicating the root of a random access preamble and a second cyclic shift, wherein the first response message may be used by the UE based on the second cyclic shift being spaced from the cyclic shift by a distance less than the cyclic shift monitoring range; and sending a second response message based on the first response message.

[0014] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, the first set of cyclic shifts may be generated based on a second set of cyclic shifts and a set of cyclic shift offsets including a first cyclic shift step, and the second cyclic shift may be a cyclic shift in the second set of cyclic shifts.

[0015] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, receiving a first response message may include operations, features, components, or instructions for receiving a second random access message indicating a timing advance offset for sending a second response message.

[0016] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, sending a second response message may include operations, features, components, or instructions for sending a third random access message based on a timing advance offset and a cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0017] In some examples of the methods described herein, UEs, and non-transitory computer-readable media, the second cyclic shift may be spaced apart from the cyclic shift based on the propagation delay between the UE and the network entity associated with the serving cell.

[0018] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, sending a second response message may include operations, features, components, or instructions for sending a third random access message based on a timing advance offset corresponding to the difference between a second cyclic shift and a cyclic shift, wherein the third random access message may be sent based on the difference being less than the cyclic shift monitoring range.

[0019] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, sending a third random access message may include operations, features, components, or instructions for sending the third random access message based on a timing advance offset and a cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0020] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, the size of the cyclic shift monitoring range may be the same as the first cyclic shift step size of the first set of cyclic shifts.

[0021] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, the cyclic shift monitoring range may be greater than or equal to the first cyclic shift step of the first set of cyclic shifts.

[0022] In some examples of the methods, UEs, and nontransitory computer-readable media described herein, receiving a first response message may include operations, features, components, or instructions for receiving a conflict resolution message indicating one or more random access channel timings for sending a second response message, wherein the second response message may be sent via one or more random access channel timings.

[0023] In the methods described herein, and in some examples of UEs and nontransitory computer-readable media, RTT corresponds to a threshold RTT supported by the serving cell.

[0024] A method for wireless communication by a network entity is described. The method may include: sending to a first UE and a second UE a control message indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size smaller than the RTT associated with a serving cell of the network entity; receiving from the first UE a first random access message from one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts; receiving from the second UE a second random access message from one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts; and transmitting a response message for the first UE based on the control message, the first cyclic shift, and the second cyclic shift.

[0025] A network entity for wireless communication is described. The network entity may include: one or more memories storing processor-executable code; and one or more processors coupled to the one or more memories. The one or more processors may be able to operate individually or jointly to execute code such that the network entity: sends to a first UE and a second UE a control message indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size smaller than the RTT associated with the serving cell of the network entity; receives from the first UE a first random access message of one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts; receives from the second UE a second random access message of one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts; and transmits a response message for the first UE based on the control message, the first cyclic shift, and the second cyclic shift.

[0026] Another network entity for wireless communication is described. This network entity may include: means for sending a control message to a first UE and a second UE indicating a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size smaller than the RTT associated with the serving cell of the network entity; means for receiving a first random access message from the first UE among one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts; means for receiving a second random access message from the second UE among one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts; and means for sending a response message for the first UE based on the control message, the first cyclic shift, and the second cyclic shift.

[0027] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: send to a first UE and a second UE a control message indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size smaller than the RTT associated with a serving cell of a network entity; receive from the first UE a first random access message from one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts; receive from the second UE a second random access message from one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts; and transmit a response message for the first UE based on the control message, the first cyclic shift, and the second cyclic shift.

[0028] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending a response message may include operations, features, components, or instructions for: determining that the first random access message and the second random access message may be separable in the cyclic shift domain; and sending a random access response message that includes a timing advance offset and an indication of a third cyclic shift based on the first cyclic shift.

[0029] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending control messages may include operations, features, components, or instructions for: sending control messages indicating the cyclic shift monitoring range, and random access response messages for a first UE based on a third cyclic shift distance from a first cyclic shift within the cyclic shift monitoring range.

[0030] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, the first set of cyclic shifts may be generated based on a second set of cyclic shifts and a set of cyclic shift offsets including a first cyclic shift step, and the third cyclic shift may be a cyclic shift in the second set of cyclic shifts.

[0031] The methods, network entities, and some examples of nontransitory computer-readable media described herein may also include operations, features, components, or instructions for calculating timing advance offsets based on third cyclic shifts.

[0032] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, the third cyclic shift may be the same as the first cyclic shift.

[0033] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, random access response messages include a Media Access Control Control Element (MAC-CE).

[0034] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending a response message may include operations, features, components, or instructions for: determining that a first cyclic shift may be the same as a second cyclic shift and that a first random access message and a second random access message are received at the same time; and sending a conflict resolution message for a first UE based on a control message and the determination, the conflict resolution message including an indication of a third cyclic shift that may be based on the first cyclic shift.

[0035] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, the first set of cyclic shifts may be generated based on a second set of cyclic shifts and a set of cyclic shift offsets including a first cyclic shift step, and the third cyclic shift may be a cyclic shift in the second set of cyclic shifts.

[0036] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, the third cyclic shift may be the same as the first cyclic shift.

[0037] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending a conflict resolution message may include operations, features, components, or instructions for sending a conflict resolution message that indicates the timing of one or more random access channels for a first UE to send a second response message.

[0038] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending control messages may include operations, features, components, or instructions for: sending control messages indicating cyclic shift monitoring ranges, and responding to messages based on third cyclic shifts and monitoring ranges for use by a first UE.

[0039] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, sending a response message may include operations, features, components, or instructions for sending the response message based on a comparison between a first random access message and a second random access message, the comparison being based on prior collision information associated with the serving cell, multipath information associated with the serving cell, or a combination thereof.

[0040] In some examples of the methods, network entities, and nontransitory computer-readable media described herein, the RTT can be the maximum RTT of the serving cell. Attached Figure Description

[0041] Figure 1 Examples of wireless communication systems supporting collision reduction for random access procedures according to one or more aspects of this disclosure are shown.

[0042] Figure 2 Examples of wireless communication systems supporting collision reduction for random access procedures according to one or more aspects of this disclosure are shown.

[0043] Figure 3A and Figure 3B An example of a cyclic shift graph supporting collision reduction for a random access procedure, according to one or more aspects of this disclosure, is shown.

[0044] Figure 4A and Figure 4B An example of a cyclic shift graph supporting collision reduction for a random access procedure, according to one or more aspects of this disclosure, is shown.

[0045] Figure 5 An example of a process flow supporting conflict reduction for a random access procedure is shown, according to one or more aspects of this disclosure.

[0046] Figure 6 and Figure 7 A block diagram of an apparatus supporting collision reduction for a random access procedure, according to one or more aspects of this disclosure, is shown.

[0047] Figure 8 A block diagram is shown of a communication manager that supports collision reduction for random access procedures according to one or more aspects of this disclosure.

[0048] Figure 9A diagram is shown of a system including devices that support collision reduction for random access procedures, according to one or more aspects of this disclosure.

[0049] Figure 10 and Figure 11 A block diagram of an apparatus supporting collision reduction for a random access procedure, according to one or more aspects of this disclosure, is shown.

[0050] Figure 12 A block diagram is shown of a communication manager that supports collision reduction for random access procedures according to one or more aspects of this disclosure.

[0051] Figure 13 A diagram is shown of a system including devices that support collision reduction for random access procedures, according to one or more aspects of this disclosure.

[0052] Figures 14 to 19 A flowchart illustrating a method for conflict reduction in a random access procedure according to one or more aspects of this disclosure is shown. Detailed Implementation

[0053] In wireless communication networks, a random access procedure can be used to establish a connection between a network entity and a user equipment (UE) within a cell. To initiate a random access procedure, the UE may transmit a Physical Random Access Channel (PRACH) preamble in a first transmission (e.g., a first random access message) to the network entity. The preamble may include a preamble sequence or examples of preamble sequences, which may also be referred to herein as a PRACH sequence, root sequence, etc. To generate the preamble, the UE may select a preamble sequence from a set of preamble sequences configured for the random access procedure. The UE may generate the preamble based on the selected preamble sequence and a selected cyclic shift from a set of cyclic shifts. The set of preamble sequences and the set of cyclic shifts provide distinction between preambles transmitted from multiple UEs, since each UE transmitting the preamble may select a different preamble sequence and cyclic shift. That is, the network entity may detect that a received preamble originates from a different UE based on the association of each preamble with a different preamble sequence. Additionally or alternatively, each preamble may have a different arrival time at the network entity based on its corresponding cyclic shift. Therefore, even if two UEs select the same preamble sequence, the network entity can detect that the received preamble originates from different UEs based on the different arrival times of each preamble at the network entity.

[0054] In some examples, a set of preamble sequences can be assigned on a per-cell or per-network entity basis. Therefore, the set of preamble sequences should include a sufficient number of preamble sequences such that two UEs in a cell are unlikely to select the same preamble sequence at the same or similar times. Additionally, the set of cyclic shifts can be associated with a cyclic shift step size (e.g., the interval between each cyclic shift in the set of cyclic shifts) that prevents overlap in cyclic shifts detected by the network entity, for example, based on the cell size and the corresponding propagation delay. However, in some scenarios, such as in large cells with many UEs, there is still a chance of contention for, for example, two or more different UEs, to initiate a random access procedure by sending the same preamble sequence at the same or similar times. For example, the number of preamble sequences may be finite and may be insufficient for the cell. As another example, in smaller cells, if two UEs select the same cyclic shift for the corresponding preamble, the corresponding propagation delay may not be sufficient to provide a difference between the arrival times of the preamble received at the network entity.

[0055] In such scenarios, the network entity may be unable to distinguish between two UEs. For example, when multiple preambles have the same or similar arrival times at the network entity, especially if the preambles are associated with the same preamble sequence or cyclic shift, the network entity may not detect that a single preamble has been received, making the random access procedure potentially successful for one UE. The other UE will then have to re-initiate the random access procedure, wasting resources and increasing the time delay for the other UE to establish a connection with the network entity. Furthermore, when the number of preamble sequences is limited, the probability that multiple UEs will choose the same preamble sequence can increase with the number of UEs in the cell.

[0056] Therefore, the techniques described herein support cyclic shifting for transmitting preambles during random access, enabling network entities to differentiate received preambles even when these preambles have the same or similar arrival times at the network entity. For example, a UE may transmit a random access preamble based on cyclic shifts from a first set of cyclic shifts associated with a cyclic shift step size smaller than the round-trip time (RTT) (e.g., maximum RTT) of the cell associated with the UE. In some examples, a UE may generate a first set of cyclic shifts based on a second set of cyclic shifts (e.g., nominal cyclic shifts with a second step size greater than or equal to the RTT) and a set of cyclic shift offsets, where this set of cyclic shift offsets is associated with an offset step size smaller than the RTT of the UE's serving cell (e.g., having a regular or consistent offset step size). Cyclic shift offsets enable receiving network entities to distinguish random access preambles conveyed by multiple different UEs, for example, even when two (or more) UEs select the same cyclic shift. Additionally or alternatively, the cyclic shift step size of the first set of cyclic shifts can be a consistent (e.g., regular) step size smaller than the RTT. For example, this can provide a larger number of cyclic shifts for the first set of cyclic shifts compared to a set of cyclic shifts with a step size greater than or equal to the RTT. Therefore, the likelihood that a network entity cannot distinguish the received preamble can be reduced without increasing the number of available preamble sequences in the set of preamble sequences. That is, the chance that two or more different UEs generate corresponding preambles based on the same preamble sequence and cyclic shift described herein (e.g., compared to preambles generated solely based on the preamble sequence and conventional cyclic shift) is reduced. Based on distinguishing the received preamble, the network entity can send a corresponding Random Access Response (RAR) message to each transmitting UE (e.g., each UE that transmitted the preamble) to continue the random access procedure.

[0057] The techniques described herein also support resolving preamble collisions at the network entity. For example, if a network entity detects that a collision has occurred between preambles, such as if the network entity cannot identify the corresponding originating UE for each preamble, the network entity may send one or more collision resolution messages. These messages may indicate one or more pairs of cyclic shift and preamble sequences detected by the network entity, along with one or more random access opportunities (ROs) for subsequent transmission by the UE. The UE may receive the collision resolution message, and if the indicated cyclic shift / preamble sequence pair matches the cyclic shift and preamble sequence used by the UE to generate the preamble, the UE may retransmit the preamble to the network entity via the indicated RO. By specifying the RO for preamble retransmission, the network entity can prevent further preamble collisions, allowing the UE to continue the random access procedure without additional delay.

[0058] The various aspects of this disclosure are first described in the context of a wireless communication system. Then, these aspects are discussed with reference to cyclic shift diagrams and process flows. The various aspects of this disclosure are further illustrated and described with reference to apparatus diagrams, system diagrams, and flowcharts related to conflict reduction in random access procedures.

[0059] Figure 1 Examples of wireless communication systems 100 supporting collision reduction for random access procedures according to one or more aspects of this disclosure are shown. Wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, wireless communication system 100 may be a Long Term Evolution (LTE) network, an Advanced LTE (LTE-A) network, an LTE-A Pro network, a New Radio (NR) network, or a network operating under other systems and radio technologies including future systems and radio technologies not explicitly mentioned herein.

[0060] Network entity 105 may be distributed across a geographical area to form wireless communication system 100, and may include devices employing different forms or having different capabilities. In various examples, network entity 105 may be referred to as a network element, mobility element, radio access network (RAN) node, or network equipment, among other designations. In some examples, network entity 105 and UE 115 may wirelessly communicate via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, network entity 105 may support coverage area 110 (e.g., a geographical coverage area) within which UE 115 and network entity 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographical area within which network entity 105 and UE 115 may support the transmission of signals according to one or more radio access technologies (RATs).

[0061] UE 115 can be distributed throughout the coverage area 110 of wireless communication system 100, and each UE 115 can be stationary or mobile, or stationary and mobile at different times. UE 115 can be devices in different forms or with different capabilities. Figure 1 Some example UE 115s are illustrated herein. The UE 115 described herein can be able to support various types of devices (such as, e.g., ...). Figure 1 It communicates with other UEs (115 or network entity 105) as shown.

[0062] As described herein, nodes of the wireless communication system 100 (which may be referred to as network nodes or wireless nodes) may be network entity 105 (e.g., any network entity described herein), UE 115 (e.g., any UE described herein), network controller, apparatus, device, computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, a node may be UE 115. Alternatively, a node may be network entity 105. Furthermore, a first node may be configured to communicate with a second or third node. In one aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be UE 115. In another aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different from these examples. Similarly, references to UE 115, network entity 105, device, equipment, computing system, etc., may include disclosures of UE 115, network entity 105, device, equipment, computing system, etc., as nodes. For example, a disclosure that UE 115 is configured to receive information from network entity 105 also discloses that a first node is configured to receive information from a second node.

[0063] In some examples, network entity 105 may communicate with core network 130, communicate with each other, or both. For example, network entity 105 may communicate with core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, network entities 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entities 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. Backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be or include one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof. UE 115 can communicate with core network 130 via communication link 155.

[0064] One or more network entities in network entity 105 described herein may include or be referred to as base station 140 (e.g., transceiver base station, radio base station, NR base station, access point, radio transceiver, node B, eNodeB (eNB), next-generation node B or gigabit node B (any of which may be referred to as gNB), 5G NB, next-generation eNB (ng-eNB), home node B, home evolution node B, or other suitable terms). In some examples, network entity 105 (e.g., base station 140) may be implemented in an aggregated (e.g., monolithic, standalone) base station architecture that may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as base station 140).

[0065] In some examples, network entity 105 may be implemented in a decomposed architecture (e.g., a decomposed base station architecture, a decomposed RAN architecture) that can be configured to utilize protocol stacks physically or logically distributed across two or more network entities 105, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, network entity 105 may include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near real-time RIC, a non-real-time RIC), a service management and orchestration (SMO) 180 system, or any combination thereof. 170 may also be referred to as a radio headend, intelligent radio headend, remote radio headend (RRH), remote radio unit (RRU), or transmit / receive point (TRP). One or more components of network entity 105 in a decomposed RAN architecture may be co-located, or one or more components of network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 in a decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0066] The functional splitting among CU 160, DU 165, and RU 170 is flexible and can support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, or RU 170. For example, a protocol stack functional splitting can be used between CU 160 and DU 165, allowing CU 160 to support one or more layers of the protocol stack, and DU 165 to support one or more different layers of the protocol stack. In some examples, CU 160 can host higher protocol layer (e.g., Layer 3 (L3), Layer 2 (L2)) functionalities and signaling (e.g., Radio Resource Control (RRC), Serving Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)). CU 160 can connect to one or more DU 165 or RU 170, and one or more DU 165 or RU 170 can host lower protocol layers, such as Layer 1 (L1) (e.g., Physical (PHY) layer) or L2 (e.g., Radio Link Control (RLC) layer, Medium Access Control (MAC) layer) functionality and signaling, and each can be at least partially controlled by CU 160. Additionally or alternatively, a protocol stack functional split can be employed between DU 165 and RU 170, such that DU 165 can support one or more layers of the protocol stack, and RU 170 can support one or more different layers of the protocol stack. DU 165 can support one or more different cells (e.g., via one or more RU 170). In some cases, functional decomposition between CU 160 and DU 165, or between DU 165 and RU 170, can be performed within the protocol layer (e.g., some functions of the protocol layer can be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer can be performed by different of CU 160, DU 165, or RU 170). CU 160 can be further functionally decomposed into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 can be connected to one or more DU 165 via midhaul communication link 162 (e.g., F1, F1-c, F1-u), and DU 165 can be connected to one or more RU 170 via fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some examples, the midhaul communication link 162 or the fronthaul communication link 168 may be implemented based on the interfaces (e.g., channels) between the layers of the protocol stack, which are supported by the corresponding network entities 105 communicating via such communication links.

[0067] In some wireless communication systems (e.g., wireless communication system 100), the infrastructure and spectrum resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB node 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DU 165s or one or more RU 170s may be partially controlled by one or more CU 160s associated with donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB node 104) via supported access and backhaul links (e.g., backhaul communication link 120). IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a DU 165 of a coupled IAB donor. The IAB-MT may include a separate set of antennas for relaying communication with UE 115, or may share the same antennas (e.g., those of RU 170) for access to IAB node 104 via DU 165 of IAB node 104. (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of IAB node 104) may be configured to operate according to the techniques described herein.

[0068] For example, the access network (AN) or RAN may include communication between an access node (e.g., an IAB donor), IAB node 104, and one or more UEs 115. The IAB donor may facilitate connectivity between the core network 130 and the AN (e.g., via a wired or wireless connection to the core network 130). That is, an IAB donor may refer to a RAN node having a wired or wireless connection to the core network 130. The IAB donor may include a CU 160 and at least one DU 165 (e.g., and RU 170), wherein the CU 160 may communicate with the core network 130 via an interface (e.g., a backhaul link). The IAB donor and IAB node 104 may communicate via an F1 interface according to a protocol defining the signaling messages (e.g., the F1 AP protocol). Additionally or alternatively, the CU 160 may communicate with the core network via an interface (which may be part of a backhaul link) and may communicate with other CU 160s (e.g., CU 160 associated with an alternative IAB donor) via an Xn-C interface (which may be part of a backhaul link).

[0069] IAB node 104 may refer to a RAN node that provides IAB functionality (e.g., access for UE 115, radio self-backhaul capability, etc.). DU 165 may act as a distributed scheduling node toward child nodes associated with IAB node 104, and IAB-MT may act as a scheduled node toward a parent node associated with IAB node 104. That is, an IAB donor may be referred to as a parent node communicating with one or more child nodes (e.g., an IAB donor may relay for UE transmissions via one or more other IAB nodes 104). Additionally or alternatively, depending on the AN's relay chain or configuration, IAB node 104 may also be referred to as a parent or child node of other IAB nodes 104. Therefore, the IAB-MT entity of IAB node 104 can provide a Uu interface for child IAB node 104 to receive signaling from parent IAB node 104, and the DU interface (e.g., DU 165) can provide a Uu interface for parent IAB node 104 to send signaling notifications to child IAB node 104 or UE 115.

[0070] For example, IAB node 104 may be referred to as a parent node supporting communication to child IAB nodes, or as a child IAB node associated with an IAB donor, or both. An IAB donor may include a CU 160 having a wired or wireless connection to core network 130 (e.g., backhaul communication link 120) and may act as a parent node of IAB node 104. For example, the IAB donor's DU 165 may relay transmissions to UE 115 via IAB node 104, or may signal transmissions directly to UE 115, or both. The IAB donor's CU 160 may signal the establishment of a communication link to IAB node 104 via an F1 interface, and IAB node 104 may schedule transmissions via DU 165 (e.g., transmissions relayed from the IAB donor to UE 115). That is, data may be relayed to and from IAB node 104 via signaling through the NR Uu interface of the MT to IAB node 104. Communication with IAB node 104 can be scheduled by DU 165 of the IAB donor, and communication with IAB node 104 can be scheduled by DU 165 of IAB node 104.

[0071] In the context of applying the techniques described herein to a decomposed RAN architecture, one or more components of the decomposed RAN architecture can be configured to support conflict reduction for random access procedures, as described herein. For example, some operations described as being performed by UE 115 or network entity 105 (e.g., base station 140) may additionally or alternatively be performed by one or more components of the decomposed RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0072] UE 115 may include or be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or any other suitable term, wherein "device" may also be referred to as a cell, station, terminal, or client, etc. UE 115 may also include or be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine-type communication (MTC) device, etc., which may be implemented in various objects such as appliances or vehicles, meters, etc.

[0073] The UE 115 described herein can communicate with various types of devices, such as other UEs 115 that sometimes act as relays, network entities 105, and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, etc. Figure 1 As shown.

[0074] UE 115 and network entity 105 can wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" can refer to a set of RF spectrum resources having a physical layer structure defined for supporting communication link 125. For example, a carrier for communication link 125 may include a portion of the RF spectrum band (e.g., a bandwidth portion (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating carrier operation, user data, or other signaling. Wireless communication system 100 may support communication with UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used in conjunction with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers. Communication between network entity 105 and other devices can refer to communication between these devices and any part of network entity 105 (e.g., entity, sub-entity). For example, the terms “send,” “receive,” or “communicate” when referring to network entity 105 can refer to any part of the RAN’s network entity 105 (e.g., base station 140, CU160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0075] In some examples, such as in carrier aggregation configurations, a carrier may also have acquisition signaling or control signaling to coordinate the operation of other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute RF Channel Number (EARFCN)) and may be identified according to a channel grating used for discovery by UE 115. A carrier may operate in standalone mode, in which case initial acquisition and connection can be performed by UE 115 via that carrier, or the carrier may operate in non-standalone mode, in which case different carriers (e.g., the same or different radio access technologies) are used to anchor the connection.

[0076] The communication link 125 shown in the wireless communication system 100 may include downlink transmission (e.g., forward link transmission) from network entity 105 to UE 115, uplink transmission (e.g., return link transmission) from UE 115 to network entity 105, or both, as well as other transmission configurations. A carrier may carry downlink communication or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink and uplink communication (e.g., in TDD mode).

[0077] A carrier may be associated with a specific bandwidth of the RF 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 bandwidth in a set of bandwidths for a particular radio access technology (e.g., 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 40 MHz, or 80 MHz). Devices of the wireless communication system 100 (e.g., network entity 105, UE 115, or both) may have hardware configurations that support communication using a specific carrier bandwidth, or may be configured to support communication using one carrier bandwidth in a set of carrier bandwidths. In some examples, the wireless communication system 100 may include network entity 105 or UE 115 that supports concurrent communication using carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate using a portion (e.g., subband, BWP) or all of the carrier bandwidth.

[0078] The signal waveform transmitted via a carrier may include multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform extended OFDM (DFT-S-OFDM)). In a system employing MCM, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and subcarrier spacing may be inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the decoding rate of the modulation scheme, or both), such that a relatively high number of resource elements (e.g., in the transmission duration) and a relatively high modulation scheme order correspond to a relatively high communication rate. Wireless communication resources may refer to a combination of RF spectrum resources, temporal resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial resources may increase the data rate or data integrity used for communication with UE 115.

[0079] It can support one or more sets of parameters for a carrier, and the set of parameters may include subcarrier spacing ( (and cyclic prefix). A carrier can be divided into one or more BWPs with the same or different sets of parameters. In some examples, UE 115 can be configured with multiple BWPs. In some examples, a single BWP of a carrier can be active at a given time, and the communication of UE 115 can be constrained to one or more active BWPs.

[0080] The time interval for network entity 105 or UE 115 can be expressed as a multiple of a basic time unit, such as the sampling period. seconds, of which It can represent the supported subcarrier spacing, and This can represent the supported Discrete Fourier Transform (DFT) size. The time interval of the communication resources can be organized according to radio frames, each with a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

[0081] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may (e.g., in the time domain) be divided into subframes, and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, time slots may be further divided into multiple micro-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., The duration of a symbol period is associated with a (number) sampling period. The duration of a symbol period can depend on the subcarrier spacing or the operating frequency band.

[0082] A subframe, time slot, micro-time slot, or symbol can be the smallest scheduling unit of the wireless communication system 100 (e.g., in the time domain) and can be referred to as a transmission time interval (TTI). In some examples, the duration of the TTI (e.g., the number of symbol periods in the TTI) can be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 can be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0083] Depending on the technology, carriers can be used to multiplex physical channels for communication. One or more of Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), or hybrid TDM-FDM techniques can be used, for example, to multiplex physical control channels and physical data channels for signaling via a downlink carrier. The control region of the physical control channel (e.g., a control resource set (CORESET)) can be defined by a set of symbol periods and can extend across the system bandwidth of the carrier or a subset of that bandwidth. One or more control regions (e.g., CORESET) can be configured for a set of UEs 115. For example, one or more UEs in UE 115 can monitor or search control regions to obtain control information based on one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a concatenated manner. The aggregation level of control channel candidates can refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space set may include: a common search space set configured to transmit control information to multiple UEs 115, and a UE-specific search space set used to transmit control information to a specific UE 115.

[0084] Network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used to communicate with network entity 105 (e.g., using a carrier) and may be associated with an identifier used to distinguish adjacent cells (e.g., Physical Cell Identifier (PCID), Virtual Cell Identifier (VCID), or other cell identifier). In some examples, a cell may also refer to a coverage area 110 or a portion of coverage area 110 (e.g., a sector) in which a logical communication entity operates. Depending on various factors such as the capabilities of network entity 105, the range of such cells may range from smaller areas (e.g., structures, subsets of structures) to larger areas. For example, a cell may be or may include buildings, subsets of buildings, or external space between or overlapping coverage areas 110, etc.

[0085] Macro cells typically cover a relatively large geographical area (e.g., a radius of several kilometers) and allow unrestricted access to UE 115 that has a service subscription with a network provider supporting the macro cell. In contrast, small cells can be associated with a lower-power network entity 105 (e.g., a lower-power base station 140) and can operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells can provide unrestricted access to UE 115 that has a service subscription with a network provider, or restricted access to UE 115 associated with a small cell (e.g., UE 115 in a Closed Subscriber Group (CSG), or UE 115 associated with a user in a home or office). Network entity 105 can support one or more cells and can also use one or more component carriers to support communication via one or more cells.

[0086] In some examples, a carrier can support multiple cells and can be configured with different cells based on different protocol types that can provide access for different types of devices (e.g., MTC, Narrowband IoT (NB-IoT), Enhanced Mobile Broadband (eMBB)).

[0087] In some examples, network entity 105 (e.g., base station 140, RU 170) may be mobile, and thus provide communication coverage to mobile coverage areas 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 use the same or different radio access technologies to provide coverage for various coverage areas 110.

[0088] The wireless communication system 100 can support synchronous or asynchronous operation. For synchronous operation, network entities 105 (e.g., base station 140) can have similar frame timings, and transmissions from different network entities 105 can be approximately time-aligned. For asynchronous operation, network entities 105 can have different frame timings, and in some examples, transmissions from different network entities 105 may not be time-aligned. The techniques described herein can be used for both synchronous and asynchronous operation.

[0089] Some UE 115 devices (such as MTC or IoT devices) can be low-cost or low-complexity devices and can provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with each other or with network entity 105 (e.g., base station 140) without human intervention. In some examples, M2M communication or MTC may include communication from devices with integrated sensors or meters to measure or acquire information and relay such information to a central server or application that uses the information or presents it to people interacting with the application. Some UE 115 devices may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geographic event monitoring, queue management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0090] Some UE 115s can be configured to operate in a power-saving mode, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but does not involve concurrent transmission and reception). In some examples, half-duplex communication can be performed at a reduced peak rate. Other power-saving techniques for UE 115s include entering a power-saving deep sleep mode when not engaged in active communication, operating with limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UE 115s can be configured to operate using a narrowband protocol type associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a carrier's guard band, or outside a carrier.

[0091] Wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). UE 115 may be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communication may include private or group communication and may be supported by one or more services, such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritization of services, and such services may be used for public safety or general business applications. The terms “ultra-reliable,” “low-latency,” and “ultra-reliable low-latency” are used interchangeably herein.

[0092] In some examples, UE 115 may be configured to support direct communication with other UE 115s via device-to-device (D2D) communication link 135 (e.g., according to peer-to-peer (P2P), D2D, or sidelink protocols). In some examples, one or more UE 115s performing D2D communication in a group may be within the coverage area 110 of network entity 105 (e.g., base station 140, RU 170), which may support aspects of such D2D communication configured (e.g., scheduled by network entity 105). In some examples, one or more UE 115s in such a group may be outside the coverage area 110 of network entity 105, or may otherwise be unable or not configured to receive transmissions from network entity 105. In some examples, the group of UE 115s communicating via D2D communication may support a one-to-many (1:M) system, where each UE 115 transmits to each of the other UE 115s in the group. In some examples, network entity 105 may facilitate the scheduling of resources used for D2D communication. In other examples, D2D communication may be performed between UEs 115 without involving network entity 105.

[0093] 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., UE 115). In some examples, vehicles may communicate using vehicle-to-vehicle (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles may signal information related to traffic conditions, signaling, weather, safety, emergencies, or any other information relevant to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure (such as roadside units), or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or both.

[0094] Core network 130 provides user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. Core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), and may include at least one control plane entity (e.g., a Mobility Management Entity (MME), Access and Mobility Management Function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), or User Plane Function (UPF)) for routing packets or interconnecting to external networks. The control plane entity manages non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by network entity 105 (e.g., base station 140) associated with core network 130. User IP packets can be delivered through user plane entities, which provide IP address allocation and other functions. User plane entities may connect to one or more network operator IP services 150. IP services 150 may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0095] Wireless communication system 100 can operate using one or more frequency bands in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is referred to as the Ultra High Frequency (UHF) region or decimeter band because the wavelength range is approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clusters), but these waves are sufficient to penetrate structures so that macrocells can provide service to UE 115 located indoors. Compared to communication using smaller frequencies and longer waves in the High Frequency (HF) or Very High Frequency (VHF) portions of the spectrum below 300 MHz, communication using UHF waves can be associated with smaller antennas and shorter ranges (e.g., less than 100 km).

[0096] The wireless communication system 100 can also operate in the Ultra High Frequency (SHF) band (also known as the centimeter band) in the range of 3 GHz to 30 GHz or in the Extremely High Frequency (EHF) band (e.g., 30 GHz to 300 GHz) (also known as the millimeter band) using the spectrum. In some examples, the wireless communication system 100 can support millimeter-wave (mmW) communication between the UE 115 and the network entity 105 (e.g., base station 140, RU170), and the EHF antennas of the corresponding devices can be smaller and more closely spaced than UHF antennas. In some examples, such techniques facilitate the use of antenna arrays within the device. However, compared to SHF or UHF transmission, EHF transmission may experience even greater attenuation and a shorter range. The techniques disclosed herein can be adopted for transmission across one or more different frequency bands, and the frequency band usage specified across these frequency bands may vary by country or regulatory authority.

[0097] Wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, wireless communication system 100 may use unlicensed frequency bands (such as the 5 GHz Industrial, Scientific, and Medical (ISM) band) to employ licensed assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology. When operating with unlicensed RF spectrum bands, devices such as network entity 105 and UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation using unlicensed frequency bands may be combined with component carriers operating with licensed frequency bands based on carrier aggregation configurations (e.g., LAA). Operation using unlicensed spectrum may include downlink transmission, uplink transmission, P2P transmission, or D2D transmission, etc.

[0098] Network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of network entity 105 or UE 115 may be located within one or more antenna arrays or antenna panels, which can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly such as an antenna tower. In some examples, the antennas or antenna arrays associated with network entity 105 may be located at different geographical locations. Network entity 105 may include an antenna array having a collection of multiple rows and columns of antenna ports that network entity 105 can use to support beamforming for communication with UE 115. Similarly, UE 115 may include one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0099] Network entity 105 or UE 115 can use MIMO communication to leverage multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. This technique is known as spatial multiplexing. The multiple signals can be transmitted, for example, by a transmitting device via different antennas or different combinations of antennas. Similarly, the multiple signals can be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry information associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include: single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device; and multi-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

[0100] Beamforming (also known as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting or receiving device (e.g., network entity 105, UE 115) to shape or guide an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting and receiving devices. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array such that some signals propagating along a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to the signals transmitted via the antenna elements may include applying amplitude shifts, phase shifts, or both to the signals carried via the antenna elements associated with the device. The adjustments associated with each of these antenna elements may be defined by a beamforming weight set associated with a specific orientation (e.g., relative to the antenna array of the transmitting or receiving device or relative to some other orientation).

[0101] Network entity 105 or UE 115 may use beam scanning technology as part of beamforming operations. For example, network entity 105 (e.g., base station 140, RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by network entity 105 along different directions. For example, network entity 105 may transmit signals according to different beamforming weight sets associated with different transmission directions. Transmission along different beam directions may be used to identify (e.g., by a transmitting device (such as network entity 105) or by a receiving device (such as UE 115)) the beam direction for later transmission or reception by network entity 105.

[0102] Some signals (such as data signals associated with a specific receiving device) may be transmitted by a transmitting device (e.g., transmitting network entity 105, transmitting UE 115) along a single beam direction (e.g., the direction associated with the receiving device (such as receiving network entity 105 or receiving UE 115). In some examples, the beam direction associated with transmission along a single beam direction may be determined based on the signals transmitted along one or more beam directions. For example, UE 115 may receive one or more signals transmitted by network entity 105 along different directions and may report to network entity 105 an indication of signals received by UE 115 with the highest signal quality or other acceptable signal quality.

[0103] In some examples, transmissions performed by a device (e.g., network entity 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital pre-decoding or beamforming to generate a combined beam for transmission (e.g., from network entity 105 to UE 115). UE 115 may report feedback indicating pre-decoding weights for one or more beam directions, and this feedback may correspond to a set of beams configured across the system bandwidth or one or more sub-bands. Network entity 105 may transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may or may not be pre-decoded. UE 115 may provide feedback for beam selection, which may be a pre-decoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel codebook, linear combination codebook, port selection codebook). Although these techniques are described with reference to signals transmitted by network entity 105 (e.g., base station 140, RU 170) along one or more directions, UE 115 may use similar techniques to transmit signals multiple times along different directions (e.g., to identify the beam direction used by UE 115 for subsequent transmission or reception), or to transmit signals along a single direction (e.g., to transmit data to a receiving device).

[0104] A receiving device (e.g., UE 115) may perform reception operations according to multiple reception configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a transmitting device (e.g., network entity 105). For example, the receiving device may perform reception according to multiple reception directions by: receiving via different antenna subarrays; processing the received signal according to different antenna subarrays; receiving according to different sets of reception beamforming weights (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of the antenna array; or processing the received signal according to different sets of reception beamforming weights applied to signals received at multiple antenna elements of the antenna array. Any of these operations may be referred to as “listening” according to different reception configurations or reception directions. In some examples, the receiving device may use a single reception configuration to receive along a single beam direction (e.g., when a data signal is received). A single receiver configuration can be aligned along a beam direction determined based on listening according to different receiver configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0105] The wireless communication system 100 can be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or PDCP layer can be IP-based. The RLC layer performs packet segmentation and reassembly for transmission via logical channels. The MAC layer performs priority processing and multiplexing of logical channels to transport channels. The MAC layer can also use error detection, error correction, or both to support retransmission to improve link efficiency. In the control plane, the RRC layer provides the establishment, configuration, and maintenance of RRC connections between the UE 115 and network entity 105 or core network 130 that support user plane data radio bearers. The PHY layer maps transport channels to physical channels.

[0106] UE 115 and network entity 105 can support data retransmission to increase the likelihood of successful data reception. Hybrid Automatic Repeat Request (HARQ) feedback is a technique used to increase the likelihood of correctly receiving data via communication links (e.g., communication link 125, D2D communication link 135). HARQ may include a combination of error detection (e.g., using Cyclic Redundancy Check (CRC)), forward error correction (FEC), and retransmission (e.g., Automatic Repeat Request (ARQ)). HARQ can improve throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device may support same-slot HARQ feedback, in which case the device can provide HARQ feedback in a specific time slot for data received via a previous symbol in that time slot. In some other examples, the device may provide HARQ feedback in subsequent time slots or according to a different time interval.

[0107] In the wireless communication system 100, network entity 105 and UE 115 may perform connection procedures (such as RRC procedures, cell acquisition procedures, random access procedures, RRC connection procedures, and RRC configuration procedures). For example, network entity 105 and UE 115 may perform random access procedures (e.g., RACH procedures, PRACH procedures) to establish an initial connection with each other. In some other examples, network entity 105 and UE 115 may perform random access procedures to rebuild a connection after a connection failure (such as a radio link failure), or to establish a connection for handover to another network entity 105, and so on.

[0108] To initiate a random access procedure, UE 115 may transmit a first message (e.g., Msg1) including a random access preamble (also referred to as a RACH preamble, PRACH preamble, sequence, preamble sequence, PRACH sequence, etc.) via a random access channel (e.g., RACH, PRACH). Some specific implementations of the random access procedure can be contention-based (e.g., contention-based random access (CBRA)) or contention-free (e.g., contention-free random access (CFRA)). When performing a CBRA procedure (such as a 4-step random access procedure), UE 115 (and any other UE 115 attempting random access with network entity 105) may randomly select a preamble sequence from a set of preamble sequences (e.g., 64 preamble sequences), and in some cases, randomly select a cyclic shift from a set of cyclic shifts. UE 115 may use the selected preamble sequence and the selected cyclic shift to generate the random access preamble.

[0109] Upon receiving the random access preamble, network entity 105 may estimate the transmission timing of UE 115. Based on the estimated transmission timing, network entity 105 may calculate or otherwise determine the timing advance (TA) of UE 115. Network entity 105 may send a second message (e.g., Msg2, RAR) to UE 115 to indicate the TA and one or more uplink resources (e.g., time resources, frequency resources). UE 115 may send a third message (e.g., Msg3) during the random access procedure via one or more uplink resources and according to the TA. Based on the receipt of the third message, network entity 105 may send a fourth message (e.g., Msg4) to UE 115 to complete the random access procedure.

[0110] The preamble sequence can be an example of a Zadoff-Chu sequence, and a cyclic shift can be understood as a time-domain shift (e.g., a delay) of the preamble sequence. Each cyclic shift can be separated from other cyclic shifts in the set of cyclic shifts by a cyclic shift step size, which can be based on the round-trip time (RTT) of the serving cell associated with network entity 105 (e.g., propagation time, also known as propagation delay). As long as the cyclic shift step size is greater than the maximum RTT of the serving cell (and in some cases, greater than the maximum delay spread of the random access channel), the cross-correlation between different preambles based on the same cyclic shift of the preamble sequence can be zero at network entity 105. Therefore, network entity 105 can identify the originating UE 115 of the received preamble (e.g., the source UE 115 from which the preamble was transmitted) based on the corresponding preamble sequence and cyclic shift. Specifically, network entity 105 can process the preamble to detect or otherwise determine the preamble sequence and cyclic shift from which the preamble was generated. The cyclic shift detected at network entity 105 can be based on the RTT of the serving cell. That is, network entity 105 can detect which nominal cyclic shift is used to generate the preamble based on the detected cyclic shift and the propagation delay associated with the preamble.

[0111] However, in some cases, network entity 105 may fail to distinguish between multiple received preambles or transmitting UE 115. For example, if two (or more) UEs 115 unintentionally choose the same preamble sequence and the same cyclic shift to transmit the corresponding preambles, and if the two preambles arrive at network entity 105 at the same or similar arrival times after the corresponding propagation delay, the preambles may be indistinguishable in the time domain, which can be referred to as a time-domain conflict. In other words, the two preambles may appear as a single signal to network entity 105. In another example, network entity 105 may incorrectly detect the cyclic shift of each preamble. For example, the cyclic shift step size may be suboptimal, such that multiple nominal cyclic shifts may correspond to a single detected cyclic shift, or, after considering the corresponding propagation delay, the detected cyclic shifts for multiple preambles may appear identical.

[0112] The number of preamble sequences available for network entity 105 or the serving cell may be limited, and the number of cyclic shifts available for network entity 105 or the serving cell may be based on the size of the serving cell. Therefore, as the number of UEs 115 served by network entity 105 increases, the likelihood that multiple UEs 115 may choose the same preamble sequence, the same cyclic shift, or both may also increase, thereby increasing the possibility of preamble collisions.

[0113] According to the techniques described herein, wireless communication system 100 can support the use of cyclic shifts in random access procedures, wherein the cyclic shifts are derived from a first set of cyclic shifts associated with a cyclic shift step size of the serving cell RTT less than that of UE 115. This effectively increases the number of cyclic shifts, thereby enabling network entity 105 to distinguish received preambles without increasing the number of preamble sequences or the number of cyclic shifts.

[0114] For example, UE 115 may generate a first set of cyclic shifts based on a second set of cyclic shifts (e.g., a set of nominal cyclic shifts, a set of cyclic shifts with an interval greater than or equal to the RTT) and a set of cyclic shift offsets, wherein the set of cyclic shift offsets may have an offset interval less than the RTT (e.g., a consistent offset interval, which may also be referred to herein as an offset step, cyclic shift offset step, etc.). That is, the first set of cyclic shifts may be effectively equivalent to a combination of the second set of cyclic shifts and the set of cyclic shift offsets. A cyclic shift offset may be defined as an offset relative to a cyclic shift in the second set of cyclic shifts, and a cyclic shift in the second set of cyclic shifts may be referred to as a nominal cyclic shift. UE 115 may transmit a preamble based on cyclic shifts from the first set of cyclic shifts, for example, based on a combination of nominal cyclic shifts (e.g., from the second set of cyclic shifts) and cyclic shift offsets. Therefore, even if another UE115 selects the same preamble sequence or nominal cyclic shift, the cyclic shift offset can distinguish the preamble from other preambles at network entity 105.

[0115] As another example of the first set of cyclic shifts, the cyclic shift interval associated with the first set of cyclic shifts can be a consistent (e.g., regular) interval that is less than the RTT. In such an example, UE 115 may send a preamble based on a cyclic shift selected from actually more cyclic shifts available than in other cases. Therefore, even if another UE 115 selects the same preamble sequence, the increased number of cyclic shifts may reduce the chance that the other UE 115 selects the same cyclic shift, thereby increasing the chance that network entity 105 can distinguish the preamble from other preambles.

[0116] Based on the received preamble, network entity 105 may send a Random Access Response (RAR) message to UE 115 to continue the random access procedure. For example, if the preamble from UE 115 does not conflict with another preamble (e.g., in the time domain and cyclic shift domain), network entity 105 may send a second RACH message to UE 115 to continue the random access procedure.

[0117] However, if network entity 105 detects a collision between preambles, for example, if network entity 105 cannot identify the corresponding originating UE 115 for each received preamble, network entity 105 may send one or more collision resolution messages, which may also be referred to herein as msgX. These one or more collision resolution messages may indicate one or more pairs of cyclic shift and preamble sequences detected by the network entity, and one or more ROs for subsequent transmission by the UE. UE 115 may receive the collision resolution messages, and if the indicated cyclic shift / preamble sequence pair matches the cyclic shift and preamble sequence used by UE 115 to generate the preamble, UE 115 may send msgY, which may be defined as a collision resolution response message (e.g., a response message to the collision resolution message). In some cases, msgY may include one or more reference signals. Additionally or alternatively, UE 115 may retransmit the preamble to network entity 105 within msgY and via the ROs indicated in the collision resolution messages. In another example, UE 115 may select (e.g., reselect) a different preamble sequence, a different cyclic shift, or a combination thereof to generate msgY. Network entity 105 may receive msgY via the indicated RO, which avoids conflicts with other preambles from other UEs 115. In response to msgY, network entity 105 may send a RAR message (e.g., msg2) to UE 115 to continue the random access procedure.

[0118] Figure 2 An example of a wireless communication system 200 supporting collision reduction for random access procedures according to one or more aspects of this disclosure is shown. The wireless communication system 200 may implement, or be implemented by, aspects of the wireless communication system 100. For example, the wireless communication system 200 may include network entities 105-a and UE 115 (e.g., UE 115-a and UE 115-b), which may be as described in reference... Figure 1 Examples of the corresponding devices described. In some cases, network entity 105-a can be an example of one or more Transmitter-Receiver Points (TRPs). Although Figure 2 Multiple network entities 105 and UE 115 are shown in the disclosure, but it should be noted that aspects and techniques of this disclosure can be applied to any number of network entities 105, UE 115 or both.

[0119] In the wireless communication system 200, network entity 105-a serves cell 205 in which UE 115-a and UE 115-b can operate. To establish an initial link with network entity 105-a, each UE 115 can initiate a Random Access Notice (RACH) procedure. For example, UE 115-a and UE 115-b can each send a corresponding RACH preamble 210 to network entity 105-a (e.g., RACH preamble 210-a and RACH preamble 210-b, respectively), which may be referred to as msg1. In response to receiving RACH preamble 210-a and RACH preamble 210-b, network entity 105-a can send one or more first response messages 215 (e.g., msg2 or msgX) to UE 115-a and UE 115-b, respectively. In response to the first response message 215, UE 115-a and UE 115-b may send one or more second response messages 220 (e.g., msg3 or msgY) to network entity 105-a.

[0120] UE 115-a and UE 115-b can generate RACH preamble 210-a and RACH preamble 210-b, respectively. For example, UE 115-a and UE 115-b can each select (e.g., randomly select) a preamble sequence (e.g., a root) from a set of preamble sequences. Additionally, UE 115-a and UE 115-b can each select (e.g., randomly select) a cyclic shift 225 from one or more cyclic shifts 225. In some cases, one or more cyclic shifts 225 can be associated with a set of cyclic shifts configured for cell 205, network entity 105-a, or both. In some examples, network entity 105-a can send a control message to UE 115 indicating a set of cyclic shifts (e.g., a first set of cyclic shifts, a second set of cyclic shifts, or a combination thereof), a set of preamble sequences, or both.

[0121] To generate the RACH preamble 210, UE 115 may apply a selected cyclic shift 225 to a selected preamble sequence. The cyclic shift 225 may shift the preamble sequence in the frequency domain, which, from the perspective of network entity 105-a, may result in a time-domain shift (e.g., a delay) (e.g., after network entity 105-a performs a Fourier transform on the received RACH preamble 210). For example, the cyclic shift 225 may shift the preamble sequence by a fixed amount (e.g., a cyclic shift step size 245), which may allow a first preamble sequence with a first cyclic shift 225 to be orthogonal to a second preamble sequence with a second cyclic shift 225 (e.g., having the same root as the first preamble sequence) (e.g., to avoid interference or collision).

[0122] Each RACH preamble 210 can be associated with a corresponding arrival time at network entity 105-a, where the arrival time can be based on the corresponding cyclic shift 225 (e.g., because the cyclic shift 225 is converted into a delay in the time domain). The arrival time of the RACH preamble 210 can also be based on the time taken for the RACH preamble 210 to travel from the corresponding UE 115 to network entity 105-a, which can be referred to as the propagation delay (e.g., half of the RTT).

[0123] For each RACH preamble 210 received at network entity 105-a, network entity 105-a may detect or otherwise determine the corresponding preamble sequence and cyclic shift 225 used to generate the RACH preamble 210, which may further identify which UE 115 sent the RACH preamble 210. The cyclic shift 225 determined by network entity 105-a may be referred to herein as the detected cyclic shift, while the cyclic shift 225 selected by UE 115 to generate the RACH preamble 210 may be referred to herein as the nominal cyclic shift. Network entity 105-a may process the RACH preamble 210 to determine the detected cyclic shift. After taking into account the corresponding propagation delay, network entity 105-a may identify the nominal cyclic shift based on the detected cyclic shift. For example, network entity 105-a may determine which cyclic shift 225 in the set of cyclic shifts is closest to the detected cyclic shift and may select that cyclic shift 225 as the nominal cyclic shift.

[0124] To continue the RACH process initiated by RACH preamble 210, network entity 105-a may send a RAR message (e.g., msg2) to the corresponding UE 115 indicating the preamble sequence and cyclic shift 225 (e.g., nominal cyclic shift) determined by network entity 105-a. UE 115 may monitor the RAR message including the preamble sequence and cyclic shift 225 used by UE 115 to generate RACH preamble 210. In this way, the preamble sequence and cyclic shift 225 associated with RACH preamble 210 can be used as a device identifier, and network entity 105-a can distinguish RACH preamble 210 received from different UEs 115 in cell 205.

[0125] However, in some examples, a conflict may occur between two RACH preambles 210 if they are associated with the same cyclic shift 225, the same preamble sequence (e.g., the same root), and the same or similar arrival times at network entity 105-a. In such examples, RACH preambles 210-a and RACH preambles 210-b may appear as the same RACH preamble 210 to network entity 105-a. That is, network entity 105-a may not be able to determine which UE 115 sent each RACH preamble 210, or may not know that it has received two RACH preambles 210. Therefore, network entity 105-a may not accurately receive both RACH preambles 210, or may assume that only a single RACH preamble 210 has been received.

[0126] In such an example, network entity 105-a may trigger the transmission of additional messages for contention resolution resulting from such a conflict. For example, network entity 105-a may detect that RACH preamble 210-a and RACH preamble 210-b have experienced a conflict (e.g., the network entity may detect that RACH preamble 210 has been sent from more than one UE 115, but may not be able to correctly receive and decode the information in each RACH preamble 210), and may send one or more response messages 215 to UE 115. Response messages 215 may include conflict resolution messages (which may also be referred to herein as msgX) or examples of conflict resolution messages, and may signal UE 115 to send one or more response messages 220 to network entity 105-a. Response messages 215 may include, for example, which UE 115 each response message 215 can be addressed to, and one or more resources used by UE 115 to send response messages 220. That is, each response message 215 may indicate one or more parameters for the corresponding response message 220 to be sent by the corresponding UE 115. The corresponding UE 115 may determine that the response message 215 is intended for use by the UE 115 based on the preamble sequence and cyclic shift 225 indicated in the response message 215 (e.g., if the indicated preamble sequence and cyclic shift 225 match those preamble sequences and cyclic shifts used by the UE 115 to generate the corresponding RACH preamble 210), and may send the response message 220 via the indicated resources (e.g., using the indicated cyclic shift or using a randomly selected cyclic shift).

[0127] More specifically, response message 215 may indicate one or more pairs of cyclic shifts 225 and preamble sequences associated with (e.g., detected from) the received RACH preamble 210. Additionally or alternatively, response message 215 may indicate resources (e.g., one or more ROs) for UE 115 to transmit response message 220. Multiple ROs allow for more resources to reduce the likelihood of collisions between response messages 220 transmitted by different UEs 115. For example, response message 215 may indicate (e.g., via a bitmap of ROs, the number of ROs, etc.) one or more frequency domain resources, one or more time domain resources, a time domain offset (e.g., in timeslots or symbols) of the received response message 215, or some combination thereof. In some examples, response message 215 may also indicate a cyclic shift step size 245, which may differ from the cyclic shift step size 245 used to generate the RACH preamble 210.

[0128] If the preamble sequence and cyclic shift 225 indicated in the conflict resolution message are the same as those preamble sequences and cyclic shifts used by UE 115 to generate the RACH preamble 210 (e.g., if the indicated cyclic shift matches the nominal cyclic shift), then UE 115 receiving the conflict resolution message (e.g., response message 215) can determine that the conflict resolution message was addressed to UE 115. UE 115 can then reselect (e.g., randomly) the preamble sequence, and in some cases, reselect the cyclic shift 225. UE 115 can send a response message 220 (also referred to herein as msgY) to network entity 105-a, which includes the reselected preamble sequence from the dedicated resource (e.g., RO) indicated by the conflict resolution message. Thus, response message 220 can be separable (e.g., can be non-conflicting) at network entity 105-a. Specifically, each UE 115 may select a different preamble sequence to generate a corresponding response message 220, and may send the corresponding response message 220 in different ROs as indicated by response message 215. Therefore, response messages 220 may not include the same preamble sequence and may arrive at network entity 105-a at different times (e.g., based on the corresponding RO). Thus, network entity 105-a may be able to identify which UE 115 sent each response message 220 and may be able to correctly detect the corresponding preamble sequence and cyclic shift 225.

[0129] In some examples, network entity 105-a may detect a collision between RACH preambles 210 (e.g., sent from UE 115-a and UE 115-b) to trigger the transmission of response message 215 (e.g., msgX), and subsequently response message 220 (e.g., msgY) by UE 115. For example, network entity 105-a may use an algorithm to determine whether a collision has occurred (e.g., and identify the preamble sequence and cyclic shift combination associated with the collision). Network entity 105-a may provide one or more of the following as inputs to the algorithm to determine whether a collision has occurred: the number of detected taps (e.g., in the root / cyclic shift or frequency domain), historical information of the associated channel, and environmental information associated with cell 205. In some cases, network entity 105-a may use multipath detection (e.g., in the time domain) to detect collisions between RACH preambles 210. When cell 205 is relatively large, multipath detection can adequately detect collisions of RACH preamble 210, partly because the arrival times of RACH preamble 210 sent by UE 115 located throughout the cell may differ at network entity 105-a (e.g., making RACH preamble 210 separable at network entity 105-a), which is attributed to the geographically spaced UE 115-a within cell 205 (e.g., due to the different distances between each of UE 115 and network entity 105-a).

[0130] In some cases, network entity 105-a may assume that two or more RACH preambles 210 detected by multipath detection and having the same cyclic shift originate from different UEs 115. However, in other cases, a single UE 115 may transmit the RACH preamble 210 via multipath signaling. Multipath detection by network entity 105-a may mark such multipath transmissions as collisions (e.g., false alarms). Such false alarms may result in increased latency (e.g., delays) in the wireless communication system 200, increased overhead for collision resolution (e.g., signaling overhead), or both. Network entity 105-a may accordingly select parameters for multipath detection to establish a balance between false alarms and detected collisions. Additionally or alternatively, network entity 105-a may assume the existence of a collision with each RACH preamble 210 (e.g., even if a single path is detected) and may trigger collision resolution for each received RACH preamble 210, which may result in increased latency and overhead.

[0131] In other examples, network entity 105-a may not detect a collision. That is, network entity 105-a may determine that the received RACH preamble 210 comes from a single UE 115, or may be able to detect the originating UE 115 associated with each received RACH preamble 210. In such examples, response message 215 may include a RAR message (e.g., msg2) or an example of a RAR message, and response message 220 may include msg3 or an example of msg3. Here, response message 215 may indicate UE identification information (e.g., the cyclic shift 225 and preamble sequence used by the corresponding UE 115 to send the RACH preamble 210) and resource information used by UE 115 to send response message 220.

[0132] As discussed above, a collision (e.g., a single-tap collision) may occur if UE 115-a and UE 115-b select the same root and the same cyclic shift 225 for their respective RACH preambles 210, and after the propagation delay, the RACH preambles 210 have the same or similar arrival times at network entity 105-a. In such a collision, the RACH preambles 210 may not be distinguishable in the time domain (e.g., the collision could be a time-domain collision). The probability of a collision between RACH preambles 210 at network entity 105-a may be based on the number of cyclic shifts 225 in the set of cyclic shifts, the cyclic shift step size 245, the distribution of UE 115 within cell 205, the number of UE 115 operating in cell 205, or a combination thereof. For example, the arrival time of the RACH preamble 210 at network entity 105-a can be based on a propagation delay 227 determined by factors such as the location of the transmitting UE 115 in cell 205 and the distance between UE 115 and network entity 105-a. If multiple UEs 115 have similar propagation delays 227, the probability of collisions between RACH preambles 210 transmitted by UEs 115 may increase. Additionally, as the number of UEs 115 in cell 205 increases, the probability that multiple UEs can choose the same cyclic shift 225 for transmitting the corresponding RACH preamble 210 may increase.

[0133] The probability of a collision between RACH preambles 210 can be exemplified by the detected cyclic shift distribution 230. The detected cyclic shift distribution 230 can be understood as the distribution of cyclic shifts 225 detected by network entity 105-a in the corresponding RACH preamble 210, and can be based on the propagation delay 227 of the RACH preamble 210 within cell 205 and the cyclic shift 225 selected for the RACH preamble 210 (e.g., nominal cyclic shift). The arrival time of the RACH preamble 210 at network entity 105-a can be the convolution 235 of the cyclic shift 225 selected by the corresponding UE 115 and the propagation delay 227 for the RACH preamble 210. A relatively wide detected cyclic shift distribution 230 can correspond to a relatively low probability of a collision between RACH preambles 210. In contrast, in relatively small serving cells, the detected cyclic shift distribution 230 associated with cell 205 can be relatively narrow, which may correspond to a relatively high probability of RACH preamble 210 collisions.

[0134] like Figure 2 As illustrated, when the detected cyclic shift distributions 230 (e.g., detected cyclic shift distributions 230-a, 230-b, and 230-c) do not overlap, the corresponding RACH preamble 210 may not collide at network entity 105-a. Therefore, cyclic shifts 225 can be configured for cell 205 to prevent the detected cyclic shift distributions 230 from overlapping each other, which can be achieved by optimizing the cyclic shift step size 245 of the set of cyclic shifts. Cyclic shifts 225 can be spaced apart from each other by cyclic shift step size 245, where the cyclic shift step size 245 can be large enough that network entity 105-a can determine which cyclic shift 225 has been applied to RACH preamble 210. That is, the cyclic shift step size 245 should be large enough that network entity 105-a can explicitly identify the nominal cyclic shift from the detected cyclic shifts. The cyclic shift step size 245 may be based on the maximum radius of cell 205 (e.g., size, RTT), the maximum propagation delay of transmission within cell 205, or both. In some cases, the cyclic shift step size 245 may be greater than the maximum RTT associated with cell 205 (e.g., the RTT associated with UE 115 at the edge of cell 205).

[0135] Although UE 115 may randomly select (e.g., based on cyclic shift step size 245) the cyclic shift 225 for the corresponding RACH preamble 210, the detected cyclic shift distribution 230 at network entity 105-a may not be uniformly distributed, for example, based on the associated propagation delay 227. For example, in cases where UE 115 is uniformly distributed throughout cell 205, network entity 105-a may be affected by the detected cyclic shift distribution 230-d. The detected cyclic shift distribution 230-d may occur when the number of UE 115 within a relatively small radius of network entity 105-a is much smaller than the number of UE 115 within a larger radius of network entity 105-a (e.g., due to the uniform distribution of UE 115 in cell 205). In some cases, some or all of the UE 115 within cell 205 may be located at the same location within cell 205 (e.g., a hotspot). In this scenario, network entity 105-a may be affected by the detected cyclic shift distribution 230-e, and some or all of UE115 may experience the same or similar propagation delay 227.

[0136] In some other cases, the cyclic shift step size 245 associated with cyclic shift 225 may not be optimized for cell 205. In such cases, the cyclic shift step size 245 for cyclic shift 225 for UE 115 in cell 205 can be cyclic shift step size 245-b, which is conservative (e.g., larger) compared to cyclic shift step size 245-a. Here, the detected cyclic shift distribution 230-f may be shorter than cyclic shift step size 245-b, which may correspond to an increased probability of collisions.

[0137] To reduce the likelihood of collisions in cell 205, each UE 115 may perform cyclic shift jitter. That is, each UE 115 may select a cyclic shift 225 (e.g., a nominal cyclic shift), and may also select (e.g., randomly select) a cyclic shift offset from a set of jitter (e.g., closely and regularly spaced) cyclic shift offsets (e.g., offsets relative to the nominal cyclic shift). A “jitter” cyclic shift can be understood as a combination of the nominal cyclic shift and the cyclic shift offset. In some implementations, the offset step size between jitter cyclic shifts may be smaller than the cyclic shift step size 245 between nominal cyclic shifts (e.g., the offset step size may be smaller than the cell’s maximum RTT). Such implementations are described in further detail with reference to FIG3.

[0138] Additionally or alternatively, a specific embodiment of this disclosure may allow UE 115 to select a cyclic shift 225 from a set of cyclic shifts 225, wherein the cyclic shift step size 245 of the set of cyclic shifts 225 is less than the maximum RTT of cell 205. This embodiment can effectively increase the number of cyclic shifts 225 available to UE 115 and expand the detected cyclic shift distribution 230 of cell 205, which can reduce the chance of collisions between RACH preambles 210. In such an embodiment, the cyclic shift offset can be selected as zero offset. This embodiment can effectively fit more cyclic shifts 225 into the same amount of cyclic shift resources. Such an embodiment is described in further detail with reference to FIG3.

[0139] In some examples, cyclic shift jitter or a reduced cyclic shift step size 245 can cause overlap between detected cyclic shift distributions 230. In such examples, network entity 105-a may be unlikely to correctly identify the nominal cyclic shift based on the detected cyclic shift, as the detected cyclic shift may correspond to two or more nominal cyclic shifts. Network entity 105-a may therefore indicate an approximate cyclic shift in the first response message 215. Additionally or alternatively, network entity 105-a may indicate the detected cyclic shift (e.g., rather than an approximate nominal cyclic shift) in the response message 215. Such techniques are described in further detail with reference to FIG4.

[0140] Figure 3A and Figure 3B Examples of cyclic shift diagrams 300-a and 300-b supporting collision reduction for random access procedures according to one or more aspects of this disclosure are shown. Aspects of cyclic shift diagrams 300-a and 300-b may be implemented by, or be implemented by, aspects of wireless communication system 100 and wireless communication system 200. For example, cyclic shift diagrams 300-a and 300-b may be implemented by UE 115 and network entity 105 (which may be as referenced) Figure 1 (Examples of the corresponding devices described) to implement this.

[0141] UE 115 can be configured to have a set of cyclic shifts and a set of preamble sequences for use in the RACH process as described herein. For example, UE 115 can receive control messages (e.g., RRC messages, MAC-CE) indicating the set of cyclic shifts, the set of preamble sequences, or both. To increase the uniformity of the transmitted cyclic shift distribution and correspondingly reduce the probability of collisions between RACH preambles (e.g., msg1) at network entity 105, the techniques described herein can support widening (e.g., broadening) the transmitted cyclic shift distribution. That is, if the arrival time distribution associated with the transmitted cyclic shift distribution is not uniform, widening the transmitted cyclic shift distribution can reduce the probability of collisions between RACH preambles. This can be achieved by combining cyclic shift 305 (e.g., nominal cyclic shift) with offset 335 (e.g., jittered cyclic shift 305, such as...). Figure 3A (as shown), or by reducing the cyclic shift step size 310 between cyclic shifts 305 (e.g., as shown). Figure 3B (as shown in the figure) to achieve this.

[0142] Figure 3A An example of cyclic shift jitter illustrated by cyclic shift diagram 300-a is given. To generate a RACH preamble, UE 115 may select a preamble sequence from a set of preamble sequences and a cyclic shift from a first set of cyclic shifts associated with a cyclic shift step size smaller than the RTT of the UE's serving cell. The UE may generate the first set of cyclic shifts based on nominal cyclic shifts 305 (e.g., nominal cyclic shifts 305-a, nominal cyclic shifts 305-b) from a set of nominal cyclic shifts 315-a and offsets 335 (e.g., cyclic shift offsets) from a set of offsets 320 (e.g., a set of cyclic shift offsets). In some examples, each nominal cyclic shift 305 may correspond to a corresponding offset set 320. By combining each nominal cyclic shift 305 with one or more offsets 335 from the set of offsets 320, the UE 115 obtains a first set of cyclic shifts, which may herein be referred to as the set of jitter cyclic shifts 315-c. The UE may use jitter cyclic shifts 340 from the set of jitter cyclic shifts 315-c (e.g., together with a selected preamble sequence) to generate a RACH preamble. In one example, the UE 115 may perform a convolution 325 using the set of nominal cyclic shifts 315-a and the set of offsets 320 to generate the set of jitter cyclic shifts 315-c, and the UE 115 may select (e.g., randomly select) jitter cyclic shifts 340 from the set of jitter cyclic shifts 315-c.

[0143] A set 315-a of nominal cyclic shifts may be associated with a step size 310-a (e.g., cyclic shift step size) between nominal cyclic shifts 305. Step size 310-a may be defined as the interval between adjacent cyclic shifts within the set 315-a of nominal cyclic shifts, such as the interval between nominal cyclic shifts 305-a and nominal cyclic shifts 305-b. Step size 310-a may, for example, be greater than the RTT (e.g., maximum RTT) of the serving cell associated with network entity 105 and UE 115. A set 320 of offsets may be distributed such that the interval between offsets within the set 320 of offsets is less than the RTT (e.g., RTT window length, maximum RTT) of the serving cell associated with network entity 105 and UE 115. The interval between offsets may be referred to as offset step size 310-b. In some cases, control messages may indicate the set of nominal cyclic shifts 305, the set 320 of offsets, or a combination thereof. Additionally or alternatively, the control message may indicate step size 310-a, offset step size 310-b, or both.

[0144] UE 115 may transmit a RACH preamble based on a jitter cyclic shift 340, which may differ from other nominal cyclic shifts 305 selected by other UEs 115 (e.g., compared to a nominal cyclic shift 305 for which offset 335 has not yet been applied). For example, a second UE 115 may select a different jitter cyclic shift from a set 315-c of jitter cyclic shifts (e.g., other than jitter cyclic shift 340), and therefore, the RACH preamble transmitted by UE 115 and the second UE 115 may not conflict at network entity 105. Thus, if the arrival time of the RACH preamble from UE 115 at network entity 105 is the same as the arrival time of the RACH preamble from the second UE 115 (e.g., in the time domain), offset 335 (e.g., in the cyclic shift or frequency domain) may allow network entity 105 to distinguish the RACH preamble (e.g., in the time domain after performing a Fourier transform).

[0145] In some examples, UE 115 may not perform jitter. That is, UE 115 may select nominal cyclic shift 305 and may use nominal cyclic shift 305 without using set 320 of offsets. Additionally or alternatively, UE 115 may receive an indication of set 320 of offsets that includes (e.g., only includes) 0 offsets. In some cases, UE 115 may determine whether to use nominal cyclic shift 305 or jitter cyclic shift 340 from set 315-c of jitter cyclic shifts based on configuration received from network entity 105 (e.g., configuration indicated in a control message).

[0146] In some examples, network entity 105 may be unaware of the jitter performed by UE 115 (e.g., the set 320 of offsets applied to the set 315-a of nominal cyclic shifts). That is, network entity 105 may be configured to have the set 315-a of cyclic shifts, but may not be configured to have the set 315-c of jittered cyclic shifts. When the network entity receives a RACH preamble, network entity 105 may determine the detected cyclic shift (e.g., nominal cyclic shift 305 plus offset 335 from the set 320 of offsets plus the propagation delay associated with the RACH preamble). In some examples, network entity 105 may determine an approximate nominal cyclic shift based on the detected cyclic shift, for example, by determining which cyclic shift in the set 315-a of cyclic shifts is closest to the detected cyclic shift (e.g., in the cyclic shift domain).

[0147] Network entity 105 may indicate an approximate nominal cyclic shift or a detected cyclic shift to UE 115 in a first response message (e.g., in a response to a RACH preamble, such as msg2 or msgX). UE 115 may determine whether the first response message is designated for UE 115 based on the indicated cyclic shift. For example, UE 115 may monitor the first response message from network entity 105 by checking whether each received first response message includes an indication of the closest (e.g., previously) nominal cyclic shift 305 (in this case, nominal cyclic shift 305-a) to the jitter cyclic shift 340 used by UE 115 and the preamble sequence used by UE 115 to generate the RACH preamble. If the first response message includes an indication of a cyclic shift and preamble sequence that matches those used by UE 115, then UE 115 can determine that the first response message is for UE 115, and UE 115 can accordingly send a second response message (e.g., msg3 or msgY) to network entity 105. A more detailed discussion of detected cyclic shifts and approximate nominal cyclic shifts can be found in the description of Figure 4.

[0148] Figure 3BAnother example of cyclic shift jitter illustrated by cyclic shift diagram 300-b is given. Here, to reduce the probability of collisions between RACH preambles at network entity 105, UE 115 may select a nominal cyclic shift 305 (e.g., nominal cyclic shift 305-c, nominal cyclic shift 305-d) from a set of nominal cyclic shifts 315-b, wherein the set of nominal cyclic shifts 315-b has a step size 310-c (e.g., cyclic shift step size, consistent step size, regular step size) smaller than the RTT (e.g., maximum RTT) of the serving cell associated with network entity 105 and UE 115. That is, the set of nominal cyclic shifts 315-b may be a set of jitter cyclic shifts that are pre-configured and instructed to UE 115 (e.g., instead of cyclic shift jitter performed at UE 115).

[0149] UE 115 may (e.g., from network entity 105) receive a control message indicating a set 315-b of nominal cyclic shifts, an associated step size 310-c, or both. The set 315-b of nominal cyclic shifts may have a relatively larger number of cyclic shifts 305 than the set 315-a of cyclic shifts, for example, because step size 310-a is greater than or equal to RTT and step size 310-c is less than RTT. UE 115 may therefore be less likely to select the same cyclic shift 305 as another UE 115, which reduces the probability of collisions between RACH preambles. In some examples, UE 115 may perform jitter (e.g., apply an offset) on the nominal cyclic shift 305 selected from the set 315-b of nominal cyclic shifts. In some cases, the offset selected for the nominal cyclic shift 305 in the set 315-b of cyclic shifts may be a zero offset.

[0150] Network entity 105 may use an RTT window (e.g., a pre-configured window based on the size of the serving cell associated with network entity 105) to determine a nominal cyclic shift based on detected cyclic shifts. Specifically, network entity 105 may determine an approximate nominal cyclic shift based on the cyclic shift 305 closest to the detected cyclic shift in the set 315 of cyclic shifts. Network entity 105 may indicate the approximate nominal cyclic shift to UE 115 in a first response message. If the indication of the approximate nominal cyclic shift corresponds to the nominal cyclic shift 305 selected by UE 115, then UE 115 may determine whether the first response message is specified for UE 115.

[0151] In some examples (e.g., due to overlap between detected cyclic shift distributions as a result of a smaller step size 310-c, or due to jitter), the approximate nominal cyclic shift may not be the nominal cyclic shift 305 selected by UE 115 for the RACH preamble, but the first response message may still be intended for use by UE 115. That is, network entity 105 may incorrectly estimate or otherwise determine the approximate nominal cyclic shift based on the detected cyclic shift. To ensure receipt of the first response message, UE 115 may accordingly monitor the range of cyclic shifts indicated by the first response message. In other words, UE 115 may monitor the first response message indicating the estimated nominal cyclic shift within the monitoring range (e.g., window, RTT window) of the selected nominal cyclic shift 305. If UE 115 receives a first response message indicating a nominal cyclic shift within the monitoring range, UE 115 can determine that the first response message is intended for use by UE 115, and UE 115 can send a second response message (e.g., msg3, msgY) based on the first response message.

[0152] Figure 4A and Figure 4B Examples of cyclic shift diagrams 400-a and 400-b supporting collision reduction for random access procedures according to one or more aspects of this disclosure are shown respectively. Aspects of cyclic shift diagrams 400-a and 400-b may be implemented by or by aspects of wireless communication system 100, wireless communication system 200, and cyclic shift diagram 300. For example, cyclic shift diagrams 400-a and 400-b may be implemented by UE 115 and network entity 105 (which may be as referenced) Figure 1 (Examples of corresponding devices described herein) to achieve this. Although the number of cyclic shifts 405, the offset range 410, and the monitoring range 415 are shown in Figure 4, it should be noted that aspects and techniques of this disclosure may include any number of cyclic shifts 405, any offset range 410, any monitoring range 415, or any combination thereof.

[0153] In some examples, UE 115 can initiate a random access procedure by sending a first RACH message (e.g., msg1) such as a RACH preamble to network entity 105. Figure 4AIn the example, UE 115 may select (e.g., randomly select) a jitter cyclic shift and a preamble sequence from a set of preamble sequences, wherein the jitter cyclic shift is obtained via a combination of a cyclic shift 405 (e.g., a nominal cyclic shift, such as cyclic shift 405-a) from a set of cyclic shifts used for the RACH preamble and a cyclic shift offset 425 (e.g., an offset relative to cyclic shift 405-a) within an offset range 410 (e.g., the width of the set 320 of offsets as described herein with reference to FIG. 3). UE 115 may generate and transmit the RACH preamble based on the preamble sequence, cyclic shift 405-a, and cyclic shift offset 425. The offset range 410 may be associated with or correspond to the set of cyclic shift offsets from which UE 115 selects the cyclic shift offset 425, as described herein with reference to FIG. 3. The offset range 410 may be less than the RTT associated with the serving cell of UE 115 and network entity 105. UE 115 may select jitter cyclic shift based on cyclic shift 405-a and cyclic shift offset 425 to reduce the possibility of collisions between the RACH preamble and other RACH preambles sent by other UEs 115 in the serving cell of network entity 105.

[0154] exist Figure 4B In the example, the UE may select a preamble sequence from a set of preamble sequences and a cyclic shift 405 (e.g., a nominal cyclic shift, such as cyclic shift 405-c) from a set of cyclic shifts used for the RACH preamble. Figure 4B As illustrated, cyclic shift 405 may not be associated with a cyclic shift offset; instead, the set of cyclic shifts may be pre-configured to have a step size smaller than the RTT associated with the serving cell. For example, the UE may receive a control message indicating the set of cyclic shifts and, in some cases, the step size. The UE may generate a RACH preamble based on the preamble sequence and cyclic shift 405-c.

[0155] In some examples, the RACH preamble may conflict with a second RACH preamble (e.g., sent by the second UE 115) at network entity 105. That is, the RACH preamble and the second RACH preamble may have the same root and the same cyclic shift 405, causing network entity 105 to detect a single RACH preamble (e.g., not both the RACH preamble and the second RACH preamble). In such examples, network entity 105 may send a first response message (e.g., a conflict resolution message, such as msgX) indicating the resources for the second response message (e.g., msgY) to each of UE 115 and the second UE 115, as referenced. Figure 2 As described.

[0156] Alternatively, when the RACH preamble does not conflict with the second RACH preamble, network entity 105 may detect cyclic shifts (such as detected cyclic shift 430 (e.g., detected cyclic shift 430-a, detected cyclic shift 430-b)) and the preamble sequence (e.g., the root) associated with the received RACH preamble. Network entity 105 may estimate a nominal cyclic shift based on the detected cyclic shift 430. For example, the estimated nominal cyclic shift may be a first cyclic shift that occurred before the detected cyclic shift 430, such as... Figure 4A The example of cyclic shift 405-b or Figure 4B The example shows a cyclic shift 405-d. Network entity 105 may send an indication of the cyclic shift to UE 115, for example, in a first response message (e.g., msg2, msgX). In some cases, the indicated cyclic shift may be an estimated nominal cyclic shift (e.g., the first response message may indicate cyclic shift 405-b or cyclic shift 405-d). In other cases, the indicated cyclic shift may be a detected cyclic shift 430 (e.g., the first response message may indicate a detected cyclic shift 430). Here, the first response message may include a MAC-CE having a format associated with indicating a detected cyclic shift, or an example of a MAC-CE having a format associated with indicating a detected cyclic shift.

[0157] Network entity 105 may send a first response message to UE 115 indicating a preamble sequence and a cyclic shift. UE 115 may determine that the first response message is for UE 115 based on the preamble sequence and cyclic shift indicated in the first response message. In some cases, to determine that the first response message is for UE 115, UE 115 may determine that the preamble sequence is the same as the preamble sequence selected by UE 115 for a first RACH message sent by UE 115. In some cases (e.g., when the indicated cyclic shift is a nominal cyclic shift), to determine that the first response message is for UE 115, UE 115 may determine that the indicated cyclic shift is a cyclic shift 405-a (e.g., a nominal cyclic shift) selected by UE 115 for a RACH preamble sent by UE 115. In some other cases (e.g., when the indicated cyclic shift is the detected cyclic shift 430), in order to determine that the first response message is for UE 115, UE 115 may determine that the indicated cyclic shift is spaced less than the monitoring range 415 from the cyclic shift 405 selected by UE 115 (e.g., the indicated cyclic shift is within the monitoring range).

[0158] For example, such as Figure 4AAs illustrated, based on a cyclic shift offset of 425, when UE 115 selects a cyclic shift of 405-a for the RACH preamble, network entity 105 can determine the estimated nominal cyclic shift as cyclic shift 405-b. That is, while transmitting the RACH preamble based on the cyclic shift and the cyclic shift offset can prevent collisions between RACH preambles, the cyclic shift offset may cause network entity 105 to incorrectly estimate the nominal cyclic shift used for the RACH preamble. Figure 4A In the example, an offset 425 relative to cyclic shift 405-a may fall near cyclic shift 405-b (e.g., a subsequent cyclic shift in the set of cyclic shifts) within the cyclic shift domain, causing network entity 105 to detect cyclic shift 420-a as occurring after cyclic shift 405-b. Network entity 105 can then determine the estimated nominal cyclic shift as cyclic shift 405-b. Figure 4B In the example, the smaller step size associated with cyclic shift 405 allows network entity 105 to detect cyclic shift 430 as occurring after cyclic shift 405-d, causing network entity 105 to determine the estimated nominal cyclic shift as cyclic shift 405-d.

[0159] To account for the possibility that network entity 105 may select a subsequent cyclic shift from the nominal cyclic shift selected by UE 115, UE 115 may monitor a first response message indicating any cyclic shift within monitoring range 415. In some examples, monitoring range 415 may extend from cyclic shift 405 selected by the UE through one or more other cyclic shifts 405 following the cyclic shift selected by the UE. UE 115 may monitor a first response message indicating a cyclic shift 405 falling within monitoring range 415. In some examples, UE 115 may receive control messages indicating the configuration of monitoring range 415, such as the number of cyclic shifts within monitoring range 415.

[0160] In some examples, the monitoring range 415 may be the same as or smaller than the step size of the cyclic shift 405. In such examples, UE 115 may monitor a first response message indicating the selection of the cyclic shift 405 by UE 115 for the RACH preamble. In some examples, and as discussed herein, the offset range 410 may be smaller than the step size of the cyclic shift 405. In such examples, UE 115 may monitor a first response message indicating the selection of the cyclic shift 405 for the first RACH message, as well as any other cyclic shifts falling within the monitoring range 415.

[0161] In some examples, network entity 105 may indicate the preamble sequence and the detected cyclic shift 430 in the first response message. That is, network entity 105 may indicate the detected cyclic shift 430 instead of the estimated nominal cyclic shift 405. The detected cyclic shift 430 may be the sum of the nominal cyclic shift 405 (e.g., cyclic shift 405-a, cyclic shift 405-c) selected by UE 115, the cyclic shift offset (e.g., cyclic shift offset 425), and the propagation delay associated with the RACH preamble.

[0162] UE 115 may determine that the first response message is for UE 115 based on monitoring range 415. That is, UE 115 may be configured to have monitoring range 415 based on (e.g., by network entity 105) the size of the cell associated with network entity 105. Specifically, monitoring range 415 may be associated with the propagation delay between UE 115 and network entity 105 (e.g., as necessary due to this propagation delay). In some cases, monitoring range 415 may be associated with the edge of the cell (e.g., monitoring range 415 may be based on the maximum propagation delay of the cell). Additionally or alternatively, UE 115 may determine monitoring range 415 based on propagation delay, nominal cyclic shift 405, cyclic shift offset 425, or any combination thereof.

[0163] In some examples, UE 115 may receive a first response message indicating a preamble sequence used by UE 115 and a cyclic shift 405 falling within the monitoring range 415. UE 115 may accordingly determine that the first response message is for UE 115 and may send a second response message (e.g., msgY) via one or more resources (e.g., RO) indicated by the first response message.

[0164] In some examples, the RACH preamble from UE 115 and the second RACH preamble from the second UE 115 may not conflict at network entity 105. In such examples, network entity 105 may send a first response message (e.g., a RAR message, msg2) to each of UE 115 and the second UE 115, which indicates the resources for a corresponding second response message (e.g., msg3) to be sent by the UE. That is, the first response message may include the RAR message or msg2 or an example thereof, and the second response message may include msg3 or an example thereof.

[0165] In such examples, the first response message may indicate a TA offset 420 for UE 115 to send a second response message, where the TA offset 420 indicates the timing at which UE 115 will send the second response message. In some cases, network entity 105 may determine (e.g., calculate, operate) the TA offset 420 based on the detected cyclic shift 430. For example, the network entity may determine the TA offset as TA offset 420-a between the cyclic shift 405 selected for the RACH preamble (e.g., cyclic shift 405-a, cyclic shift 405-c) and the detected cyclic shift 430. In other examples, network entity 105 may determine the TA offset 420-b based on the estimated nominal cyclic shift (e.g., cyclic shift 405-b, cyclic shift 405-d) (e.g., instead of the detected cyclic shift 430).

[0166] In some cases, if UE 115 performs jitter, the UE may have to adjust the TA offset 420 indicated by network entity 105 based on the jitter, for example, to send the second response message at an appropriate timing. That is, network entity 105 may not be aware of the jitter applied by UE 115 (e.g., applying offset 425 or a reduced step size), and therefore the TA offset 420 may be based on a cyclic shift 405 different from the cyclic shift 405 selected by UE 115 for the RACH preamble. For example, the network entity may indicate TA offset 420-b to UE 115 based on the detected cyclic shift 430 and the estimated nominal cyclic shift (e.g., cyclic shift 405-b or cyclic shift 405-d). However, the correct TA offset for the cyclic shift 405 selected by the UE (e.g., cyclic shift 405-a or cyclic shift 405-c) could be TA offset 420-a. Therefore, the UE can determine the correct TA offset of the cyclic shift 405 selected by the UE, even if the correct TA offset is different from the TA offset indicated by the network entity.

[0167] Alternatively or additionally, UE 115 may determine an adjusted TA offset, such as TA offset 420-c, based on the cyclic shift offset 425 and the TA offset 420 indicated by network entity 105. For example, if network entity 105 indicates TA offset 420-a, the UE may subtract the cyclic shift offset 425 from TA offset 420-a to determine the adjusted TA offset 420-c. Alternatively or additionally, UE 115 may determine whether the TA offset 420 exceeds the cyclic shift offset 425, and UE 115 may determine based on this whether the first response message is for UE 115. For example, if the TA offset 420 does not exceed the cyclic shift offset 425, UE 115 may determine that the first response message is not for UE 115.

[0168] In some examples, the TA offset 420 indicated by the network entity in the first response message may be based on whether the network entity correctly estimates the nominal cyclic shift. For example, if the estimated nominal cyclic shift determined by the network entity is the cyclic shift 405 selected by UE 115 (e.g., network entity 105 correctly estimated the nominal cyclic shift), the first response message may indicate TA offset 420-a. If the estimated nominal cyclic shift is not the cyclic shift 405 selected by the UE for the RACH preamble (e.g., network entity 105 incorrectly approximates the nominal cyclic shift), the first response message may indicate TA offset 420-b. Therefore, if UE 115 detects a first response message indicating the cyclic shift 405 selected for the first RACH message, UE 115 may use TA offset 420-a, cyclic shift offset 425, or both to calculate an adjusted TA offset 420 (e.g., TA offset 420-c). If UE 115 detects a first response message indicating that a cyclic shift 405 was not selected for the RACH preamble, UE 115 may use TA offset 420-b, cyclic shift offset 425, the offset between the cyclic shift selected for the first RACH message and the indicated cyclic shift 405 (e.g., step size, one or more step sizes), or some combination thereof to calculate an adjusted TA offset 420 (e.g., TA offset 420-c).

[0169] In some examples, network entity 105 may use a MAC-CE format different from the msg2 format to send the first response message, where the MAC-CE format provides an indication of the detected cyclic shift 430 (e.g., rather than the estimated nominal cyclic shift). In such examples, UE 115 may compare the detected cyclic shift 430 with a cyclic shift offset 425 and may determine a TA offset 420 based on the gap between the detected cyclic shift 430 and the cyclic shift offset 425 (e.g., if the gap is within the RTT window). That is, UE 115 may determine the gap between the cyclic shift 405 selected for the RACH preamble and the detected cyclic shift 430, where the gap is adjusted for the cyclic shift offset 425 based on the detected cyclic shift 430.

[0170] Figure 5An example of a process flow 500 supporting conflict reduction for a random access procedure according to one or more aspects of this disclosure is shown. Aspects of process flow 500 may implement aspects of wireless communication system 100, wireless communication system 200, cyclic shift diagram 300, and cyclic shift diagram 400, or may be implemented by these aspects. For example, process flow 500 may include one or more UEs 115 (e.g., UE 115-c and UE 115-d) and network entity 105 (e.g., network entity 105-b), which may be as described in reference... Figure 1 Examples of the corresponding devices described.

[0171] In the following description of process flow 500, operations between network entities 105-b, UE 115-c, and UE 115-d may be sent in a different order than the example order shown. Some operations may also be omitted from process flow 500, and other operations may be added to process flow 500. Furthermore, although some operations or signaling are shown to occur at different times for discussion purposes, these operations may actually occur simultaneously.

[0172] At 505-a, network entity 105-b may send, and UE 115-c may receive, a control message indicating a first set of cyclic shifts for sending a random access message (e.g., msg1) including a random access preamble. In some examples, the first set of cyclic shifts may have a cyclic shift step size greater than the maximum (e.g., a maximum value or threshold) RTT associated with the serving cell of network entity 105-b. In other examples, the first set of cyclic shifts may have a cyclic shift step size less than the maximum RTT associated with the serving cell of network entity 105-b. In some examples, the control message may also indicate a cyclic shift monitoring range (e.g., in a cyclic shift domain) for UE 115-c to monitor response messages from network entity 105-b. The cyclic shift monitoring range may be based on the RTT associated with the serving cell of network entity 105-b.

[0173] In some cases, the control message may additionally or alternatively indicate a second set of cyclic shifts (e.g., a cyclic shift step size greater than the RTT) and a set of cyclic shift offsets. In some cases, the set of cyclic shift offsets may have offset intervals smaller than the RTT (e.g., the offset step size between each cyclic shift offset in the set of cyclic shift offsets). In some cases, UE 115-c may generate a first set of cyclic shifts based on the second set of cyclic shifts and the set of cyclic shift offsets. For example, UE 115-c may perform a convolution of the second set of cyclic shifts and the set of cyclic shift offsets to obtain the first set of cyclic shifts.

[0174] Additionally or alternatively, the control message may indicate a first set of cyclic shifts having a consistent (e.g., regular) cyclic shift interval (e.g., the cyclic shift step size between each cyclic shift in the set of cyclic shifts) less than the RTT. In other words, the cyclic shift interval associated with the first set of cyclic shifts indicated by the control message may be a consistent interval between each cyclic shift in the first set of cyclic shifts.

[0175] In some examples, at 505-b, network entity 105-b may send, and UE 115-d may receive, a second control message indicating a first set of cyclic shifts (e.g., and cyclic shift monitoring ranges), a second set of cyclic shifts, a set of cyclic shift offsets, or some combination thereof. In some cases, the second control message may include information similar to the control message (e.g., the same information as the control message).

[0176] At 510-a, UE 115-c can transmit and network entity 105-b can receive a random access message including a random access preamble. UE 115-c can transmit a first RACH message using a first cyclic shift from a first set of cyclic shifts, wherein UE 115-c combines a set of cyclic shift offsets with a second set of cyclic shifts to obtain a first set of cyclic shifts, and then selects a first cyclic shift from the first set of cyclic shifts. The set of cyclic shift offsets may have a cyclic shift offset step size smaller than the maximum (e.g., maximum value) RTT associated with the serving cell of network entity 105-b. In some examples (e.g., if the set of cyclic shifts has a cyclic shift step size smaller than the maximum RTT associated with the serving cell), the cyclic shift offset in the set of offsets may be equal to zero.

[0177] In some examples, at 510-b, UE 115-d can send and network entity 105-b can receive a second random access message (e.g., msg1) including a second random access preamble. UE 115-b can use a second cyclic shift from the set of cyclic shifts to send the second random access message, wherein a second cyclic shift offset is applied to the second cyclic shift. In some examples, the second cyclic shift and the second cyclic shift offset can be the same as the first cyclic shift and the first cyclic shift offset.

[0178] At point 515, network entity 105-b may perform a RACH collision detection procedure. For example, network entity 105-b may determine whether the random access message and the second random access message are separable in the cyclic shift domain by comparing a first cyclic shift and a second cyclic shift. In some examples (e.g., if the random access message and the second random access message are separable in the cyclic shift domain or are associated with different preamble sequences or different cyclic shifts), based on the comparison, network entity 105-b may determine that no collision exists. In some examples (e.g., if the random access message and the second random access message are received at the same time and are associated with the same preamble sequence or the same cyclic shift), based on the comparison, network entity 105-b may determine that a collision exists. In some examples, the RACH collision detection procedure may be based on previous collision information associated with the serving cell, multipath information associated with the serving cell, or both.

[0179] In some examples, at 520, network entity 105-b may perform TA offset calculation. Network entity 105-b may determine a third cyclic shift (e.g., a detected cyclic shift or a nominal cyclic shift) associated with a random access message received from UE 115-c. The third cyclic shift may be a first cyclic shift used by UE 115-c. Alternatively, the third cyclic shift may be a cyclic shift different from the set of cyclic shifts. In some cases, the third cyclic shift may be a cyclic shift detected by network entity 105-b (e.g., when a random access message is received from UE 115-c). The third cyclic shift may be based on the propagation delay between UE 115-c and network entity 105-b. Network entity 105-b may use the third cyclic shift to calculate or otherwise determine the TA offset. The TA offset may, for example, be greater than or equal to the cyclic shift offset.

[0180] At 525-a, network entity 105-b can send and UE 115-c can receive a first response message. In some examples (e.g., if network entity 105-b determines that no collision exists), the first response message can be a RAR message (e.g., a second random access message, such as msg2). In such examples, the first response message can indicate a TA offset and a third cyclic shift (e.g., and a preamble sequence associated with the random access message). In other examples (e.g., if network entity 105-b determines that a collision exists), the response message can be a collision resolution message (e.g., msgX). In such examples, the collision resolution message can indicate a third cyclic shift (e.g., and a preamble sequence associated with the random access message) and one or more ROs for UE 115-c to send a second response message.

[0181] In some examples, at 525-b, in response to a second random access message sent by UE 115-d, network entity 105-b may send and UE 115-d may receive a first response message (e.g., msg2 or a conflict resolution message, such as msgX). The first response message may indicate one or more of a fourth cyclic shift, a TA offset, and a preamble sequence associated with the second random access message (e.g., as described with reference to steps 520 and 525-a). In some examples, one or both of the first response messages may be a MAC-CE message.

[0182] At 530-a, UE 115-c can monitor the first response message. UE 115-c can determine that the response message is for UE 115-c based on the first response message indicating a cyclic shift (e.g., a third cyclic shift) falling within the cyclic shift monitoring range from the first cyclic shift (e.g., and indicating the preamble sequence associated with the random access message). In some examples, the cyclic shift monitoring range can be the same as or larger than the step size of the set of cyclic shifts associated with it.

[0183] At 530-b, UE 115-d can monitor the first response message. UE 115-d can determine that the response message is for UE 115-d based on the first response message indicating a cyclic shift (e.g., the fourth cyclic shift) falling within the cyclic shift monitoring range from the second cyclic shift (e.g., and indicating the preamble sequence associated with the second random access message).

[0184] At 535-a, in some examples (e.g., if the first response message is a RAR message), UE 115-c may calculate the TA offset of the second response message (e.g., msg3). For example, UE 115-c may use the TA offset indicated in the first response message at 525-a to calculate the TA offset of the second response message. The calculated TA offset may be calculated, for example, based on the difference between the first cyclic shift and the third cyclic shift. The calculated TA offset may be greater than or equal to the first cyclic shift offset.

[0185] At 535-b, in some examples (e.g., if the first response message is a RAR message), UE 115-d may calculate the TA offset of the second response message (e.g., msg3). For example, UE 115-d may use the TA offset indicated in the first response message at 525-b to calculate the TA offset of the second response message. The calculated TA offset may be calculated, for example, based on the difference between the second cyclic shift and the fourth cyclic shift. The calculated TA offset may be greater than or equal to the second cyclic shift offset.

[0186] At 540-a, UE 115-c may send a second response message to network entity 105-b. UE 115-c may use the indicated TA offset, the calculated TA offset, and one or more resources indicated in the first response message at 525-a to send the second response message. In some examples (e.g., if the first response message is a RAR message), the second message may be a third random access message (e.g., msg3). In other examples (e.g., if the first response message is a conflict resolution message), the second response message may be a conflict resolution response message (e.g., msgY). Here, UE 115-c may send the conflict resolution response message via the RO indicated by the first response message at 525-a.

[0187] At 540-b, UE 115-d may send a second response message to network entity 105-b. UE 115-d may use the indicated TA offset, the calculated TA offset, and one or more resources indicated in the first response message at 525-b to send the second response message. In some examples (e.g., if the first response message is a RAR message), the second message may be a third random access message (e.g., msg3). In other examples (e.g., if the first response message is a conflict resolution message), the second response message may be a conflict resolution response message (e.g., msgY). Here, UE 115-d may send the conflict resolution response message via the RO indicated by the first response message at 525-b.

[0188] Figure 6 A block diagram 600 illustrates a device 605 supporting collision reduction for random access procedures according to one or more aspects of this disclosure. Device 605 may be an example of aspects of UE 115 as described herein. Device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. Device 605, or one or more components of device 605 (e.g., receiver 610, transmitter 615, and communication manager 620), may include at least one processor that may be coupled to at least one memory to individually or jointly support or implement the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0189] Receiver 610 may provide components for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, and information channels related to collision reduction for random access procedures). Information may be passed to other components of device 605. Receiver 610 may utilize a single antenna or a collection of antennas.

[0190] Transmitter 615 may provide components for transmitting signals generated by other components of device 605. For example, transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to collision reduction for random access procedures). In some examples, transmitter 615 may be co-located with receiver 610 in a transceiver module. Transmitter 615 may utilize a single antenna or a collection of multiple antennas.

[0191] The communication manager 620, receiver 610, transmitter 615, or various combinations thereof, or various components thereof, may be examples of components used to perform various aspects of collision reduction for random access procedures as described herein. For example, the communication manager 620, receiver 610, transmitter 615, or various combinations thereof, or components thereof, may be able to perform one or more of the functions described herein.

[0192] In some examples, the communication manager 620, receiver 610, transmitter 615, or various combinations or components thereof may be implemented in hardware (e.g., in communication management circuitry). The hardware may include at least one of the following: a processor, digital signal processor (DSP), central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, microcontroller, discrete gate or transistor logic component, discrete hardware component, or any combination thereof, configured as or otherwise individually or collectively to support components for performing the functions described herein. In some examples, at least one processor and at least one memory coupled to said at least one processor may be configured to perform one or more of the functions described herein (e.g., executing instructions stored in at least one memory individually or collectively by one or more processors).

[0193] Additionally or alternatively, the communication manager 620, receiver 610, transmitter 615, or various combinations or components thereof may be implemented in code (e.g., as communication management software or firmware) executed by at least one processor. If implemented in code executed by at least one processor, the functionality of the communication manager 620, receiver 610, transmitter 615, or various combinations or components thereof may be performed by a general-purpose processor, DSP, CPU, ASIC, FPGA, microcontroller, or any combination of these or other programmable logic devices (e.g., configured as or otherwise individually or jointly to support components for performing the functions described in this disclosure).

[0194] In some examples, the communication manager 620 may be configured to use or otherwise cooperate with the receiver 610, transmitter 615, or both to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, the communication manager 620 may receive information from the receiver 610, transmit information to the transmitter 615, or be integrated in combination with the receiver 610, transmitter 615, or both to acquire information, output information, or perform various other operations as described herein.

[0195] The communication manager 620 may support wireless communication according to examples disclosed herein. For example, the communication manager 620 may be capable of, configured to, or operable to support components for receiving control messages indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble. The communication manager 620 may be capable of, configured to, or operable to support components for transmitting a random access message based on cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of the UE.

[0196] By including or configuring a communication manager 620 according to an example as described herein, device 605 (e.g., at least one processor that controls or is otherwise coupled to receiver 610, transmitter 615, communication manager 620, or a combination thereof) can support techniques for more efficient use of communication resources and reduced power consumption. For example, by transmitting a random access preamble based on a cyclic shift and a cyclic shift offset, device 605 can avoid collisions with other random access preambles transmitted by other devices. By avoiding such collisions, device 605 can avoid repeating the random access process using additional resources and power consumption.

[0197] Figure 7 A block diagram 700 illustrates a device 705 supporting collision reduction for random access procedures according to one or more aspects of this disclosure. Device 705 may be an example of aspects of device 605 or UE 115 as described herein. Device 705 may include a receiver 710, a transmitter 715, and a communication manager 720. Device 705, or one or more components of device 705 (e.g., receiver 710, transmitter 715, and communication manager 720), may include at least one processor that may be coupled to at least one memory to support the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0198] Receiver 710 may provide components for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, and information channels related to collision reduction for random access procedures). Information may be passed to other components of device 705. Receiver 710 may utilize a single antenna or a collection of antennas.

[0199] Transmitter 715 may provide components for transmitting signals generated by other components of device 705. For example, transmitter 715 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to collision reduction for random access procedures). In some examples, transmitter 715 may be co-located with receiver 710 in a transceiver module. Transmitter 715 may utilize a single antenna or a collection of multiple antennas.

[0200] Device 705 or its various components may be examples of parts used to perform various aspects of collision reduction for random access procedures as described herein. For example, communication manager 720 may include RACH configuration component 725, RACH messaging component 730, or any combination thereof. Communication manager 720 may be examples of aspects of communication manager 620 as described herein. In some examples, communication manager 720 or its various components may be configured to use or otherwise cooperate with receiver 710, transmitter 715, or both to perform various operations (e.g., receive, acquire, monitor, output, transmit). For example, communication manager 720 may receive information from receiver 710, transmit information to transmitter 715, or be integrated in combination with receiver 710, transmitter 715, or both to acquire information, output information, or perform various other operations as described herein.

[0201] The communication manager 720 may support wireless communication according to examples disclosed herein. The RACH configuration component 725 is capable of, configured to, or operable to support components for receiving control messages indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble. The RACH message component 730 is capable of, configured to, or operable to support components for transmitting a random access message based on cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the UE's serving cell.

[0202] Figure 8A block diagram 800 is shown of a communication manager 820 supporting collision reduction for a random access procedure according to one or more aspects of this disclosure. The communication manager 820 may be an example of a communication manager 620, a communication manager 720, or aspects thereof as described herein. The communication manager 820 or its various components may be examples of parts for performing the various aspects of collision reduction for a random access procedure as described herein. For example, the communication manager 820 may include a RACH configuration component 825, a RACH message component 830, a circular shift component 835, a response message receiving component 840, a response message sending component 845, or any combination thereof. Each of these components, or its components or sub-components (e.g., one or more processors, one or more memories), may communicate directly or indirectly with each other (e.g., via one or more buses).

[0203] The communication manager 820 may support wireless communication according to examples disclosed herein. The RACH configuration component 825 is capable of, configured to, or operable to support components for receiving control messages indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble. The RACH message component 830 is capable of, configured to, or operable to support components for transmitting a random access message based on cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the UE's serving cell.

[0204] In some examples, to support receiving control messages indicating a first set of cyclic shifts, the RACH configuration component 825 is capable of, configured to, or operable to support components for receiving control messages indicating a second set of cyclic shifts and a set of cyclic shift offsets including a first cyclic shift step. In some examples, to support receiving control messages indicating a first set of cyclic shifts, the RACH configuration component 825 is capable of, configured to, or operable to support components for generating a first set of cyclic shifts based on the second set of cyclic shifts and the set of cyclic shift offsets.

[0205] In some examples, the cyclic shift component 835 is capable of, configured to, or operable to support components for selecting cyclic shifts from a first set of cyclic shifts, the first set of cyclic shifts having a consistent cyclic shift step size less than the RTT.

[0206] In some examples, the control message indicates a cyclic shift monitoring range based on RTT, and the response message receiving component 840 is capable, configured, or operable to support components for receiving a first response message indicating the root and second cyclic shift of a random access preamble, wherein the first response message is used by the UE based on a second cyclic shift spaced less than the cyclic shift monitoring range. In some examples, the control message indicates a cyclic shift monitoring range based on RTT, and the response message sending component 845 is capable, configured, or operable to support components for sending a second response message based on the first response message.

[0207] In some examples, the first set of cyclic shifts is generated based on the second set of cyclic shifts and the set of cyclic shift offsets that include the first cyclic shift step. In some examples, the second cyclic shift is a cyclic shift within the second set of cyclic shifts.

[0208] In some examples, in order to support receiving a first response message, the response message receiving component 840 is capable of, configured to, or operable to support a component for receiving a second random access message indicating a timing advance offset for sending a second response message.

[0209] In some examples, in order to support the sending of a second response message, the response message sending component 845 is capable of, configured to, or able to operate to support components for sending a third random access message based on a timing advance offset and a cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0210] In some examples, the second cyclic shift is spaced apart from the cyclic shift based on the propagation delay between the UE and the network entity associated with the serving cell.

[0211] In some examples, in order to support the sending of a second response message, the response message sending component 845 is capable of, configured to, or operable to support components for sending a third random access message based on a timing advance offset corresponding to the difference between the second cyclic shift and the cyclic shift, wherein the third random access message is sent based on the difference being less than the cyclic shift monitoring range.

[0212] In some examples, in order to support the transmission of a third random access message, the response message transmission component 845 is capable of, configured to, or able to operate to support components for transmitting a third random access message based on a timing advance offset and a cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0213] In some examples, the size of the cyclic shift monitoring range is the same as the first cyclic shift step size of the first set of cyclic shifts. In some examples, the size of the cyclic shift monitoring range is greater than or equal to the first cyclic shift step size of the first set of cyclic shifts.

[0214] In some examples, in order to support receiving a first response message, the response message receiving component 840 is capable of, configured to, or operable to support components for receiving a conflict resolution message indicating one or more random access channel timings for sending a second response message, wherein the second response message is sent via one or more random access channel timings.

[0215] In some examples, RTT corresponds to a threshold RTT supported by the serving cell.

[0216] Figure 9 A diagram of a system 900 including device 905 supporting collision reduction for random access procedures, according to one or more aspects of this disclosure, is shown. Device 905 may be an example of device 605, device 705, or UE 115 as described herein, or a component including such devices or UEs. Device 905 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof (e.g., wirelessly). Device 905 may include components for bidirectional voice and data communication, including components for transmitting and receiving communications, such as a communication manager 920, an input / output (I / O) controller 910, a transceiver 915, an antenna 925, at least one memory 930, code 935, and at least one processor 940. These components may communicate electronically or be coupled in other ways (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground) via one or more buses (e.g., bus 945).

[0217] I / O controller 910 manages the input and output signals of device 905. I / O controller 910 can also manage peripheral devices not integrated into device 905. In some cases, I / O controller 910 may represent a physical connection or port to an external peripheral device. In some cases, I / O controller 910 may utilize an operating system such as iOS. ® ANDROID ® MS-DOS ® MS-WINDOWS ® OS / 2 ® UNIX ® LINUX ®Alternatively, it may be another known operating system. Additionally or alternatively, the I / O controller 910 may represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, the I / O controller 910 may be implemented as part of one or more processors, such as at least one processor 940. In some cases, a user may interact with the device 905 via the I / O controller 910 or via hardware components controlled by the I / O controller 910.

[0218] In some cases, device 905 may include a single antenna 925. However, in other cases, device 905 may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. Transceiver 915 may communicate bidirectionally via one or more antennas 925 as described herein, or via a wired or wireless link. For example, transceiver 915 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 915 may also include a modem for: modulating packets; providing the modulated packets to one or more antennas 925 for transmission; and demodulating packets received from one or more antennas 925. Transceiver 915, or transceiver 915 and one or more antennas 925, may be an example of transmitter 615, transmitter 715, receiver 610, receiver 710, or any combination thereof or components thereof as described herein.

[0219] At least one memory 930 may include random access memory (RAM) and read-only memory (ROM). At least one memory 930 may store computer-readable, computer-executable code 935, including instructions that, when executed by at least one processor 940, cause device 905 to perform the various functions described herein. Code 935 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, code 935 may not be directly executable by at least one processor 940, but may enable a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, among other things, at least one memory 930 may also include a basic I / O system (BIOS) that controls basic hardware or software operations, such as interaction with peripheral components or devices.

[0220] At least one processor 940 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, at least one processor 940 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into at least one processor 940. At least one processor 940 may be configured to execute computer-readable instructions stored in memory (e.g., at least one memory 930) to cause device 905 to perform various functions (e.g., functions or tasks supporting conflict reduction for random access procedures). For example, device 905 or components of device 905 may include at least one processor 940 and at least one memory 930 coupled to or coupled to at least one processor 940, wherein at least one processor 940 and at least one memory 930 are configured to perform the various functions described herein. In some examples, at least one processor 940 may include multiple processors, and at least one memory 930 may include multiple memories. One or more of a plurality of processors may be coupled to one or more of a plurality of memories, which may be configured individually or collectively to perform the various functions described herein. In some examples, at least one processor 940 may be a component of a processing system, which may refer to a system of machines (such as a series of machines), circuitry (including, for example, one or both of processor circuitry (which may include at least one processor 940) and memory circuitry (which may include at least one memory 930)) or components that receive or receive input and process the input to produce, generate or obtain a set of outputs. The processing system may be configured to perform one or more of the functions described herein. Thus, at least one processor 940 or a processing system including at least one processor 940 may be configured, capable of being configured, or operable to cause device 905 to perform one or more of the functions described herein. Furthermore, as described herein, “configured to,” “capable of being configured,” and “operable to” are used interchangeably and may be associated with the ability to perform one or more of the functions described herein when executing code stored in at least one memory 930 or otherwise.

[0221] The communication manager 920 may support wireless communication according to examples disclosed herein. For example, the communication manager 920 may be capable of, configured to, or operable to support components for receiving control messages indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble. The communication manager 920 may be capable of, configured to, or operable to support components for transmitting a random access message based on cyclic shifts in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the UE's serving cell.

[0222] By including or configuring a communication manager 920 according to the example described herein, device 905 can support techniques for improving coordination between devices, utilizing communication resources more efficiently, and reducing latency. For example, by transmitting a random access preamble based on a cyclic shift and a cyclic shift offset, device 905 can avoid collisions with other random access preambles transmitted by other devices. Therefore, device 905 can increase the likelihood of a successful random access procedure associated with the random access preamble. Additionally, by avoiding such collisions, device 905 can avoid increased latency and wasted resources associated with failed random access procedures.

[0223] In some examples, the communication manager 920 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using a transceiver 915, one or more antennas 925, or any combination thereof, or otherwise cooperating with them. Although the communication manager 920 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 920 may be supported by or performed by at least one processor 940, at least one memory 930, code 935, or any combination thereof. For example, code 935 may include instructions that can be executed by at least one processor 940 to cause device 905 to perform various aspects of collision reduction for random access procedures as described herein, or at least one processor 940 and at least one memory 930 may be otherwise configured to perform or support such operations individually or jointly.

[0224] Figure 10A block diagram 1000 of an apparatus 1005 supporting collision reduction for random access procedures according to one or more aspects of this disclosure is shown. Apparatus 1005 may be an example of aspects of network entity 105 as described herein. Apparatus 1005 may include receiver 1010, transmitter 1015, and communication manager 1020. Apparatus 1005, or one or more components of apparatus 1005 (e.g., receiver 1010, transmitter 1015, and communication manager 1020), may include at least one processor that may be coupled to at least one memory to individually or jointly support or implement the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0225] Receiver 1010 may provide components for acquiring (e.g., receiving, determining, identifying) information (such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units)) associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack). The information may be passed to other components of device 1005. In some examples, receiver 1010 may support acquiring information by receiving signals via one or more antennas. Additionally or alternatively, receiver 1010 may support acquiring information by receiving signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof.

[0226] Transmitter 1015 may provide components for outputting (e.g., transmitting, providing, conveying, transmitting) information generated by other components of device 1005. For example, transmitter 1015 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, transmitter 1015 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, transmitter 1015 may support outputting information by transmitting signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof. In some examples, transmitter 1015 and receiver 1010 may be co-located in a transceiver, which may include or be coupled to a modem.

[0227] The communication manager 1020, receiver 1010, transmitter 1015, or various combinations thereof, or various components thereof, may be examples of components used to perform various aspects of collision reduction for random access procedures as described herein. For example, the communication manager 1020, receiver 1010, transmitter 1015, or various combinations thereof, or components thereof, may be able to perform one or more of the functions described herein.

[0228] In some examples, the communication manager 1020, receiver 1010, transmitter 1015, or various combinations or components thereof may be implemented in hardware (e.g., in communication management circuitry). The hardware may include at least one of a processor, DSP, CPU, ASIC, FPGA, or other programmable logic device, microcontroller, discrete gate or transistor logic unit, discrete hardware component, or any combination thereof, configured as or otherwise individually or collectively to support components for performing the functions described herein. In some examples, at least one processor and at least one memory coupled to said at least one processor may be configured to perform one or more of the functions described herein (e.g., executing instructions stored in at least one memory individually or collectively by one or more processors).

[0229] Additionally or alternatively, the communication manager 1020, receiver 1010, transmitter 1015, or various combinations or components thereof may be implemented in code executed by at least one processor (e.g., as communication management software or firmware). If implemented in code executed by at least one processor, the functionality of the communication manager 1020, receiver 1010, transmitter 1015, or various combinations or components thereof may be performed by a general-purpose processor, DSP, CPU, ASIC, FPGA, microcontroller, or any combination of these or other programmable logic devices (e.g., configured as or otherwise individually or jointly to support components for performing the functions described in this disclosure).

[0230] In some examples, the communication manager 1020 may be configured to use or otherwise cooperate with the receiver 1010, transmitter 1015, or both to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, the communication manager 1020 may receive information from the receiver 1010, transmit information to the transmitter 1015, or be integrated in combination with the receiver 1010, transmitter 1015, or both to acquire information, output information, or perform various other operations as described herein.

[0231] The communication manager 1020 may support wireless communication according to examples disclosed herein. For example, the communication manager 1020 may be capable of, configured to, or operable to support components for sending control messages to a first UE and a second UE, instructing the transmission of a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step smaller than the round-trip time (RTT) associated with the serving cell of a network entity. The communication manager 1020 may be capable of, configured to, or operable to support components for receiving a first random access message from a first UE in one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts. The communication manager 1020 may be capable of, configured to, or operable to support components for receiving a second random access message from a second UE in one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts. The communication manager 1020 may be capable of, configured to, or operable to support components for transmitting a response message for the first UE based on the control message, the first cyclic shift, and the second cyclic shift.

[0232] By including or configuring a communication manager 1020 according to the examples described herein, device 1005 (e.g., at least one processor that controls or is otherwise coupled to receiver 1010, transmitter 1015, communication manager 1020, or a combination thereof) can support techniques for more efficient use of communication resources and reduced latency. For example, device 1005 may be able to distinguish random access preambles received from different devices, or detect that a collision has occurred between random access preambles, which can increase the likelihood of a successful random access procedure with another device and reduce latency associated with a failed random access procedure. Additionally, device 1005 may be able to resolve such collisions by sending a collision resolution message, which can improve resource utilization efficiency.

[0233] Figure 11 A block diagram 1100 of an apparatus 1105 supporting collision reduction for random access procedures according to one or more aspects of this disclosure is shown. Apparatus 1105 may be an example of aspects of apparatus 1005 or network entity 105 as described herein. Apparatus 1105 may include receiver 1110, transmitter 1115, and communication manager 1120. Apparatus 1105, or one or more components of apparatus 1105 (e.g., receiver 1110, transmitter 1115, and communication manager 1120), may include at least one processor that may be coupled to at least one memory to support the described techniques. Each of these components may communicate with each other (e.g., via one or more buses).

[0234] Receiver 1110 may provide components for acquiring (e.g., receiving, determining, identifying) information (such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units)) associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack). The information may be passed to other components of device 1105. In some examples, receiver 1110 may support acquiring information by receiving signals via one or more antennas. Additionally or alternatively, receiver 1110 may support acquiring information by receiving signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof.

[0235] Transmitter 1115 may provide components for outputting (e.g., transmitting, providing, conveying, transmitting) information generated by other components of device 1105. For example, transmitter 1115 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, transmitter 1115 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, transmitter 1115 may support outputting information by transmitting signals via one or more wired (e.g., electrical, fiber optic) interfaces, wireless interfaces, or any combination thereof. In some examples, transmitter 1115 and receiver 1110 may be co-located in a transceiver, which may include or be coupled to a modem.

[0236] Device 1105 or its various components may be examples of parts used to perform various aspects of collision reduction for random access procedures as described herein. For example, communication manager 1120 may include RACH configuration component 1125, RACH message component 1130, response message sending component 1135, or any combination thereof. Communication manager 1120 may be examples of aspects of communication manager 1020 as described herein. In some examples, communication manager 1120 or its various components may be configured to use or otherwise cooperate with receiver 1110, transmitter 1115, or both to perform various operations (e.g., receive, acquire, monitor, output, send). For example, communication manager 1120 may receive information from receiver 1110, transmit information to transmitter 1115, or be integrated in combination with receiver 1110, transmitter 1115, or both to acquire information, output information, or perform various other operations as described herein.

[0237] Communication manager 1120 may support wireless communication according to examples disclosed herein. RACH configuration component 1125 is capable of, configured to, or operable to support components for sending control messages to a first UE and a second UE, indicating a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of a network entity. RACH message component 1130 is capable of, configured to, or operable to support components for receiving a first random access message from a first UE in one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts. RACH message component 1130 is capable of, configured to, or operable to support components for receiving a second random access message from a second UE in one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts. Response message sending component 1135 is capable of, configured to, or operable to support components for sending a response message for the first UE based on control messages, the first cyclic shift, and the second cyclic shift.

[0238] Figure 12 A block diagram 1200 is shown of a communication manager 1220 supporting collision reduction for random access procedures according to one or more aspects of this disclosure. Communication manager 1220 may be an example of aspects of communication manager 1020, communication manager 1120, or both as described herein. Communication manager 1220 or its various components may be examples of parts for performing various aspects of collision reduction for random access procedures as described herein. For example, communication manager 1220 may include RACH configuration component 1225, RACH message component 1230, response message sending component 1235, timing advance component 1240, or any combination thereof. These components, or each of their components or sub-components (e.g., one or more processors, one or more memories), may communicate directly or indirectly with each other (e.g., via one or more buses), and this communication may include communication within protocol layers of a protocol stack, communication associated with logical channels of the protocol stack (e.g., between protocol layers of the protocol stack, within devices, components, or virtualization components associated with network entity 105, between devices, components, or virtualization components associated with network entity 105), or any combination thereof.

[0239] The communication manager 1220 may support wireless communication according to examples disclosed herein. The RACH configuration component 1225 is capable of, configured to, or operable to support components for sending control messages to a first UE and a second UE, indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of a network entity. The RACH message component 1230 is capable of, configured to, or operable to support components for receiving a first random access message from a first UE in one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts. In some examples, the RACH message component 1230 is capable of, configured to, or operable to support components for receiving a second random access message from a second UE in one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts. The response message sending component 1235 is capable of, can be configured to, or is operable to support components for sending response messages for the first UE based on control messages, a first cyclic shift, and a second cyclic shift.

[0240] In some examples, to support the transmission of response messages, the response message transmission component 1235 is capable of, configured to, or operable to support components for determining that the first random access message and the second random access message are separable in the cyclic shift domain. In some examples, to support the transmission of response messages, the response message transmission component 1235 is capable of, configured to, or operable to support components for transmitting a random access response message including a timing advance offset and an indication of a third cyclic shift based on the first cyclic shift.

[0241] In some examples, in order to support the transmission of control messages, the RACH configuration component 1225 can be configured or operated to support components for transmitting control messages indicating the cyclic shift monitoring range, and the random access response message is used for the first UE based on the third cyclic shift distance from the first cyclic shift within the cyclic shift monitoring range.

[0242] In some examples, the first set of cyclic shifts is generated based on the second set of cyclic shifts and the set of cyclic shift offsets that include the first cyclic shift step. In some examples, the third cyclic shift is a cyclic shift within the second set of cyclic shifts.

[0243] In some examples, the timing advance component 1240 is capable of, configured to, or operable to support components for calculating the timing advance offset based on a third cyclic shift. In some examples, the third cyclic shift is the same as the first cyclic shift.

[0244] In some examples, the random access response message includes MAC-CE.

[0245] In some examples, to support the transmission of response messages, the response message transmission component 1235 is capable of, configured to, or operable to support components for determining that the first cyclic shift is the same as the second cyclic shift and that the first random access message and the second random access message are received at the same time. In some examples, to support the transmission of response messages, the response message transmission component 1235 is capable of, configured to, or operable to support components for transmitting a conflict resolution message for the first UE based on a control message and the determination, the conflict resolution message including an indication of a third cyclic shift based on the first cyclic shift.

[0246] In some examples, the first set of cyclic shifts is generated based on the second set of cyclic shifts and the set of cyclic shift offsets that include the first cyclic shift step. In some examples, the third cyclic shift is a cyclic shift within the second set of cyclic shifts.

[0247] In some examples, the third circular shift is the same as the first circular shift.

[0248] In some examples, in order to support the transmission of conflict resolution messages, the response message transmission component 1235 can be configured or operated to support components for transmitting conflict resolution messages that indicate the timing of one or more random access channels for the first UE to transmit a second response message.

[0249] In some examples, in order to support the transmission of control messages, the RACH configuration component 1225 is capable of, can be configured to, or is operable to support components for transmitting control messages indicating the cyclic shift monitoring range, and the response message is used for the first UE based on a third cyclic shift and monitoring range.

[0250] In some examples, in order to support the sending of response messages, the response message sending component 1235 is capable of, configured to, or able to operate to support components for sending response messages based on a comparison between a first random access message and a second random access message, the comparison being based on previous collision information associated with the serving cell, multipath information associated with the serving cell, or a combination thereof.

[0251] In some examples, RTT is the maximum RTT of the serving cell.

[0252] Figure 13A diagram of a system 1300 including device 1305 supporting collision reduction for random access procedures, according to one or more aspects of this disclosure, is shown. Device 1305 may be an example of device 1005, device 1105, or network entity 105 as described herein, or a component including such devices or network entities. Device 1305 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof, and such communication may include communication via one or more wired interfaces, one or more wireless interfaces, or any combination thereof. Device 1305 may include components that support output and obtain communication, such as a communication manager 1320, a transceiver 1310, an antenna 1315, at least one memory 1325, code 1330, and at least one processor 1335. These components may communicate electronically or otherwise (e.g., operative ground, communicative ground, functional ground, electronic ground, electrical ground) via one or more buses (e.g., bus 1340).

[0253] As described herein, transceiver 1310 may support bidirectional communication via a wired link, a wireless link, or both. In some examples, transceiver 1310 may include a wired transceiver and be capable of bidirectional communication with another wired transceiver. Additionally or alternatively, in some examples, transceiver 1310 may include a wireless transceiver and be capable of bidirectional communication with another wireless transceiver. In some examples, device 1305 may include one or more antennas 1315 that may be capable of (e.g., concurrently) transmitting or receiving wireless transmissions. Transceiver 1310 may also include a modem for modulating signals to provide modulated signals for transmission (e.g., via one or more antennas 1315, via a wired transmitter), for receiving modulated signals (e.g., from one or more antennas 1315, from a wired receiver), and for demodulating signals. In some embodiments, transceiver 1310 may include one or more interfaces, such as one or more interfaces coupled to one or more antennas 1315 configured to support various receive or acquire operations, or one or more interfaces coupled to one or more antennas 1315 configured to support various transmit or output operations, or combinations thereof. In some embodiments, transceiver 1310 may include one or more processors or one or more memory components or configured to be coupled to such processors or memory components, which are operable to perform or support operations based on received or acquired information or signals, or to generate information or other signals for transmission or other output, or any combination thereof. In some embodiments, transceiver 1310, or transceiver 1310 and one or more antennas 1315, or transceiver 1310 and one or more antennas 1315 and one or more processors or one or more memory components (e.g., at least one processor 1335, at least one memory 1325, or both) may be included in a chip or chip assembly mounted in device 1305. In some examples, transceiver 1310 may be able to operate to support communication via one or more communication links (e.g., communication link 125, backhaul communication link 120, midhaul communication link 162, and fronthaul communication link 168).

[0254] At least one memory 1325 may include RAM, ROM, or any combination thereof. At least one memory 1325 may store computer-readable, computer-executable code 1330 including instructions that, when executed by one or more of at least one processor 1335, cause device 1305 to perform the various functions described herein. Code 1330 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, code 1330 may not be directly executable by one of the at least one processor 1335, but may enable a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, at least one memory 1325 may also include a BIOS, among other things, that controls basic hardware or software operation, such as interaction with peripheral components or devices. In some examples, at least one processor 1335 may include multiple processors, and at least one memory 1325 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be configured individually or collectively to perform the various functions described herein (e.g., as part of a processing system).

[0255] At least one processor 1335 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, ASICs, CPUs, FPGAs, microcontrollers, programmable logic devices, discrete gate or transistor logic units, discrete hardware components, or any combination thereof). In some cases, at least one processor 1335 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into one or more of the at least one processor 1335. At least one processor 1335 may be configured to execute computer-readable instructions stored in memory (e.g., one or more memories in at least one memory 1325) to cause device 1305 to perform various functions (e.g., functions or tasks supporting conflict reduction for random access procedures). For example, device 1305 or components of device 1305 may include at least one processor 1335 and at least one memory 1325 coupled to one or more of the at least one processor 1335, wherein at least one processor 1335 and at least one memory 1325 are configured to perform the various functions described herein. At least one processor 1335 may be an example of a cloud computing platform (e.g., one or more physical nodes and supporting software such as an operating system, virtual machine, or container instance) that can (e.g., by executing code 1330) host functions for performing the functions of device 1305. At least one processor 1335 may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in device 1305 (such as within one or more memories of at least one memory 1325). In some examples, at least one processor 1335 may include multiple processors, and at least one memory 1325 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be configured individually or collectively to perform the various functions described herein. In some examples, at least one processor 1335 may be a component of a processing system, which may refer to a system of machines (such as a series of machines), circuits (including, for example, one or both of processor circuitry (which may include at least one processor 1335) and memory circuitry (which may include at least one memory 1325)) or components that receive or acquire input and process the input to produce, generate, or acquire a set of outputs. The processing system may be configured to perform one or more of the functions described herein. Therefore, at least one processor 1335 or a processing system including at least one processor 1335 may be configured, can be configured, or can be operated to cause the device 1305 to perform one or more of the functions described herein.Furthermore, as described herein, “configured to,” “capable of being configured to,” and “capable of operating to” are used interchangeably and may be associated with the ability to perform one or more of the functions described herein when executing code stored in at least one memory 1325 or otherwise.

[0256] In some examples, bus 1340 may support communication at the protocol layer of the protocol stack (e.g., within a protocol layer). In some examples, bus 1340 may support communication associated with logical channels of the protocol stack (e.g., between protocol layers of the protocol stack), which may include communication performed within components of device 1305, or communication performed between different components of device 1305 that are co-addressable or may be located in different locations (e.g., where device 1305 may refer to a system in which one or more of communication manager 1320, transceiver 1310, at least one memory 1325, code 1330 and at least one processor 1335 may be located in one component of different components or partitioned between different components).

[0257] In some examples, the communication manager 1320 may manage (e.g., via one or more wired or wireless backhaul links) various aspects of communication with the core network 130. For example, the communication manager 1320 may manage the delivery of data communications by client devices, such as one or more UEs 115. In some examples, the communication manager 1320 may manage communication with other network entities 105 and may include a controller or scheduler for coordinating communication with UEs 115 with other network entities 105. In some examples, the communication manager 1320 may support an X2 interface within LTE / LTE-A wireless communication network technology to provide communication between network entities 105.

[0258] Communication manager 1320 may support wireless communication according to examples disclosed herein. For example, communication manager 1320 may be capable of, configured to, or operable to support components for sending control messages to a first UE and a second UE, indicative of a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of a network entity. Communication manager 1320 may be capable of, configured to, or operable to support components for receiving a first random access message from a first UE in one or more random access messages, the first random access message being associated with a first cyclic shift based on the first set of cyclic shifts. Communication manager 1320 may be capable of, configured to, or operable to support components for receiving a second random access message from a second UE in one or more random access messages, the second random access message being associated with a second cyclic shift based on the first set of cyclic shifts. Communication manager 1320 may be capable of, configured to, or operable to support components for sending a response message for the first UE based on control messages, the first cyclic shift, and the second cyclic shift.

[0259] By including or configuring a communication manager 1320 according to the example described herein, device 1305 can support techniques for improving coordination between devices, utilizing communication resources more efficiently, and reducing latency. For example, device 1305 may be able to distinguish random access preambles received from different devices, or detect that a collision has occurred between random access preambles, which can increase the likelihood of a successful random access procedure with another device and reduce latency associated with failed random access procedures. Additionally, device 1305 may be able to resolve such collisions by sending a collision resolution message, which can improve resource utilization efficiency.

[0260] In some examples, the communication manager 1320 may be configured to use or otherwise coordinate with the transceiver 1310, one or more antennas 1315 (e.g., where applicable), or any combination thereof to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). Although the communication manager 1320 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1320 may be supported or performed by the transceiver 1310, one or more processors in at least one processor 1335, one or more memories in at least one memory 1325, code 1330, or any combination thereof (e.g., by a processing system including at least a portion of at least one processor 1335, at least one memory 1325, code 1330, or any combination thereof). For example, code 1330 may include instructions that can be executed by one or more processors in at least one processor 1335 to cause the device 1305 to perform various aspects of collision reduction for random access procedures as described herein, or at least one processor 1335 and at least one memory 1325 may be otherwise configured to perform or support such operations individually or jointly.

[0261] Figure 14 A flowchart illustrating a method 1400 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1400 may be implemented by a UE or its components as described herein. For example, operation of method 1400 may be performed by, as referenced... Figures 1 to 9 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0262] At 1405, the method may include: receiving a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble. The operation of block 1405 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1405 may be provided by reference to [reference needed]. Figure 8 The RACH configuration component 825 described is used to perform this.

[0263] At 1410, the method may include: transmitting a random access message based on cyclic shifts in a first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the UE's serving cell. The operation of block 1410 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1410 may be derived from references... Figure 8 The RACH message component 825 is described and executed.

[0264] Figure 15 A flowchart illustrating a method 1500 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1500 can be implemented by a UE or its components as described herein. For example, operation of method 1500 can be implemented by, as referenced... Figures 1 to 9 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0265] At 1505, the method may include: receiving a control message indicating a second set of cyclic shifts and a set of cyclic shift offsets including cyclic shift offsets, the set of cyclic shift offsets including a first cyclic shift step size less than the RTT associated with the serving cell of the UE. Operation of block 1505 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1505 may be provided by reference to [reference needed]. Figure 8 The RACH configuration component 825 described is used to perform this.

[0266] At 1510, the method may include: generating a first set of cyclic shifts based on a second set of cyclic shifts and a set of cyclic shift offsets, wherein the first set of cyclic shifts is used to transmit a random access message including a random access preamble. The operation of block 1510 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1510 may be derived from references... Figure 8 The RACH configuration component 825 described is used to perform this.

[0267] At 1515, the method may include: sending a random access message based on cyclic shifts in a first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size. The operation of block 1515 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1515 may be derived from references... Figure 8 The RACH message component 825 is described and executed.

[0268] Figure 16 A flowchart illustrating a method 1600 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1600 can be implemented by a UE or its components as described herein. For example, operation of method 1600 can be implemented by, as referenced... Figures 1 to 9 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0269] At 1605, the method may include: receiving a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the serving cell of the UE. Operation of block 1605 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1605 may be provided by reference to [reference needed]. Figure 8 The RACH configuration component 825 described is used to perform this.

[0270] At 1610, the method may include: selecting a cyclic shift from a first set of cyclic shifts, the first set of cyclic shifts having a consistent cyclic shift step size less than the RTT. The operation of block 1610 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1610 may be derived from references... Figure 8 The described cyclic shift component 835 is used to perform this operation.

[0271] At 1615, the method may include: sending a random access message based on the cyclic shifts in a first set of cyclic shifts. The operation of block 1615 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1615 may be derived from references... Figure 8 The RACH message component 830 is described and executed.

[0272] Figure 17 A flowchart illustrating a method 1700 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1700 can be implemented by a UE or its components as described herein. For example, operation of method 1700 can be implemented by, as referenced... Figures 1 to 9 The UE 115 described herein is used to perform this function. In some examples, the UE can execute a set of instructions to control the functional elements of the UE to perform the described function. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described function.

[0273] At 1705, the method may include: receiving a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble, wherein the control message indicates a cyclic shift monitoring range based on the RTT associated with the UE's serving cell. Operation of block 1705 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1705 may be provided by reference to... Figure 8 The RACH configuration component 825 described is used to perform this.

[0274] At 1710, the method may include: sending a random access message based on cyclic shifts in a first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT. The operation of block 1710 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1710 may be derived from references... Figure 8 The RACH message component 830 is described and executed.

[0275] At 1715, the method may include: receiving a first response message indicating the root and second cyclic shift of a random access preamble, wherein the first response message includes a conflict resolution message indicating the timing of one or more random access channels for sending a second response message, and wherein the first response message is used for the UE based on the second cyclic shift being spaced from the cyclic shift by a period smaller than the cyclic shift monitoring range. Operation of block 1715 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1715 may be derived from references... Figure 8 The described response message receiving component 840 is used to perform this action.

[0276] At 1720, the method may include: sending a second response message based on a first response message, wherein the second response message is sent via a random access channel timing of one or more random access channel timings. The operation of block 1720 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1720 may be provided by reference to [reference needed]. Figure 8 The described response message sending component 840 is used to perform this action.

[0277] Figure 18 A flowchart illustrating a method 1800 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1800 may be implemented by a network entity or its components as described herein. For example, operation of method 1800 may be implemented by, as referenced... Figures 1 to 5 as well as Figures 10 to 13 The network entity described herein performs the function. In some examples, the network entity may execute a set of instructions to control the functional elements of the network entity to perform the described function. Additionally or alternatively, the network entity may use dedicated hardware to perform aspects of the described function.

[0278] At 1805, the method may include: sending to a first UE and a second UE a control message indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the RTT associated with the serving cell of the network entity. Operation of block 1805 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1805 may be provided by reference to [reference needed]. Figure 12The RACH configuration component 1225 described herein is used for execution.

[0279] At 1810, the method may include: receiving a first random access message from a first UE, one or more random access messages, the first random access message being associated with a first cyclic shift based on a first set of cyclic shifts. Operation of block 1810 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1810 may be provided by reference to... Figure 12 The RACH message component 1230 described herein shall be used to execute this.

[0280] At 1815, the method may include: receiving a second random access message from one or more random access messages of a second UE, the second random access message being associated with a second cyclic shift based on a first set of cyclic shifts. Operation of block 1815 may be performed according to examples as disclosed herein. In some examples, aspects of operation of 1815 may be provided by reference to [reference]. Figure 12 The RACH message component 1230 described herein shall be used to execute this.

[0281] At 1820, the method may include: sending a response message for the first UE based on a control message, a first cyclic shift, and a second cyclic shift. The operation of block 1820 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1820 may be provided by reference to... Figure 12 The described response message sending component 1235 is used to execute this.

[0282] Figure 19 A flowchart illustrating a method 1900 for conflict reduction in a random access procedure, according to various aspects of this disclosure, is shown. Operation of method 1900 may be implemented by a network entity or its components as described herein. For example, operation of method 1900 may be implemented by, as referenced... Figures 1 to 5 as well as Figures 10 to 13 The network entity described herein performs the function. In some examples, the network entity may execute a set of instructions to control the functional elements of the network entity to perform the described function. Additionally or alternatively, the network entity may use dedicated hardware to perform aspects of the described function.

[0283] At 1905, the method may include: sending a second response message based on a first response message, wherein the second response message is sent via a random access channel timing of one or more random access channel timings. The operation of block 1905 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1905 may be provided by reference to [reference needed]. Figure 12 The RACH configuration component 1225 described herein is used for execution.

[0284] At 1910, the method may include: receiving a first random access message from a first UE, one or more random access messages, the first random access message being associated with a first cyclic shift based on a first set of cyclic shifts. The operation of block 1910 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1910 may be provided by reference to [reference]. Figure 12 The RACH message component 1230 described herein shall be used to execute this.

[0285] At 1915, the method may include: receiving a second random access message from one or more random access messages of a second UE, the second random access message being associated with a second cyclic shift based on a first set of cyclic shifts. The operation of block 1915 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1915 may be provided by reference to [reference needed]. Figure 12 The RACH message component 1230 described herein shall be used to execute this.

[0286] At 1920, the method may include: determining that the first random access message and the second random access message are separable in the cyclic shift domain. The operation of block 1920 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1920 may be derived from references... Figure 12 The described response message sending component 1235 is used to execute this.

[0287] At 1925, the method may include: sending a random access response message including a TA offset and an indication of a third circular shift based on a control message, a first circular shift, and a second circular shift. The operation of block 1925 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1925 may be provided by reference to [reference needed]. Figure 12 The described response message sending component 1235 is used to execute this.

[0288] The following provides an overview of the various aspects of this disclosure: Aspect 1: A method for wireless communication at a UE, the method comprising: receiving a control message indicating a first set of cyclic shifts for transmitting a random access message including a random access preamble; and transmitting the random access message according to a cyclic shift in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than a round-trip time (RTT) associated with the serving cell of the UE.

[0289] Aspect 2: According to the method of aspect 1, wherein the cyclic shift is at least partially based on a cyclic shift offset less than the RTT, and wherein receiving the control message indicating the first set of cyclic shifts includes: receiving the control message indicating a second set of cyclic shifts and a set of cyclic shift offsets including the cyclic shift offsets, the set of cyclic shift offsets including the first cyclic shift step size; and generating the first set of cyclic shifts at least partially based on the second set of cyclic shifts and the set of cyclic shift offsets.

[0290] Aspect 3: The method according to any one of Aspects 1 to 2, the method further comprising: selecting the cyclic shift from the first set of cyclic shifts, the first set of cyclic shifts having a consistent cyclic shift step size smaller than the RTT.

[0291] Aspect 4: The method according to any one of Aspects 1 to 3, wherein the control message indicates a cyclic shift monitoring range based at least in part on the RTT, the method further comprising: receiving a first response message indicating the root and second cyclic shift of the random access preamble, wherein the first response message is used for the UE based at least in part on the second cyclic shift being spaced from the cyclic shift by a distance less than the cyclic shift monitoring range; and sending a second response message based at least in part on the first response message.

[0292] Aspect 5: According to the method of aspect 4, wherein the first set of cyclic shifts is generated at least in part based on the second set of cyclic shifts and the set of cyclic shift offsets including the first cyclic shift step size, and the second cyclic shift is a cyclic shift in the second set of cyclic shifts.

[0293] Aspect 6: According to the method of aspect 5, wherein the first response message includes a second random access message, and wherein receiving the first response message includes: receiving the second random access message indicating a timing advance offset for sending the second response message.

[0294] Aspect 7: According to the method of aspect 6, wherein the cyclic shift is based at least in part on a cyclic shift offset less than the RTT, wherein the second response message includes a third random access message, and wherein sending the second response message includes: sending the third random access message based at least in part on the timing advance offset and the cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0295] Aspect 8: The method according to any one of Aspects 4 to 7, wherein the second cyclic shift is spaced apart from the cyclic shift at least in part based on the propagation delay between the UE and the network entity associated with the serving cell.

[0296] Aspect 9: According to the method of aspect 8, wherein the second response message includes a third random access message, and wherein sending the second response message includes: sending the third random access message at least in part based on a timing advance offset, the timing advance offset corresponding to the difference between the second cyclic shift and the cyclic shift, wherein the third random access message is sent at least in part based on the difference being less than the cyclic shift monitoring range.

[0297] Aspect 10: According to the method of aspect 9, wherein the cyclic shift is based at least in part on a cyclic shift offset less than the RTT, and wherein sending the third random access message comprises: sending the third random access message at least in part on the timing advance offset and the cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

[0298] Aspect 11: The method according to any one of Aspects 4 to 10, wherein the size of the cyclic shift monitoring range is the same as the size of the first cyclic shift step of the first set of cyclic shifts.

[0299] Aspect 12: The method according to any one of Aspects 4 to 10, wherein the size of the cyclic shift monitoring range is greater than or equal to the first cyclic shift step size of the first set of cyclic shifts.

[0300] Aspect 13: The method according to any one of Aspects 4 to 5, wherein the first response message includes a conflict resolution message, and wherein receiving the first response message includes: receiving the conflict resolution message indicating one or more random access channel timings for sending the second response message, wherein the second response message is sent via one of the one or more random access channel timings.

[0301] Aspect 14: The method according to any one of Aspects 1 to 13, wherein the RTT corresponds to a threshold RTT supported by the serving cell.

[0302] Aspect 15: A method for wireless communication at a network entity, the method comprising: sending to a first UE and a second UE a control message indicating a first set of cyclic shifts for transmitting one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than a round-trip time (RTT) associated with a serving cell of the network entity; receiving from the first UE a first random access message of the one or more random access messages, the first random access message being associated with a first cyclic shift at least partially based on the first set of cyclic shifts; receiving from the second UE a second random access message of the one or more random access messages, the second random access message being associated with a second cyclic shift at least partially based on the first set of cyclic shifts; and transmitting a response message for the first UE based at least partially on the control message, the first cyclic shift, and the second cyclic shift.

[0303] Aspect 16: The method according to aspect 15, wherein the response message includes a random access response message, and wherein sending the response message includes: determining that the first random access message and the second random access message are separable in a cyclic shift domain; and sending the random access response message including a timing advance offset and an indication of a third cyclic shift at least in part based on the first cyclic shift.

[0304] Aspect 17: According to the method of aspect 16, sending the control message includes: sending the control message indicating a cyclic shift monitoring range, the random access response message being used for the first UE at least in part based on the third cyclic shift distance from the first cyclic shift within the cyclic shift monitoring range.

[0305] Aspect 18: The method according to any one of Aspects 16 to 17, wherein the first set of cyclic shifts is generated at least in part based on the second set of cyclic shifts and the set of cyclic shift offsets including the first cyclic shift step size, and the third cyclic shift is a cyclic shift in the second set of cyclic shifts.

[0306] Aspect 19: The method according to aspect 18 further includes: calculating the timing advance offset based at least in part on the third cyclic shift.

[0307] Aspect 20: The method according to any one of aspects 16 to 19, wherein the third cyclic shift is the same as the first cyclic shift.

[0308] Aspect 21: According to the method of aspect 20, the random access response message includes a Media Access Control element (MAC-CE).

[0309] Aspect 22: According to the method of aspect 15, wherein the response message includes a conflict resolution message, and wherein sending the response message includes: determining that the first cyclic shift is the same as the second cyclic shift and that the first random access message and the second random access message are received at the same time; and sending the conflict resolution message for the first UE based at least in part on the control message and the determination, the conflict resolution message including an indication of a third cyclic shift based at least in part on the first cyclic shift.

[0310] Aspect 23: According to the method of aspect 22, wherein the first set of cyclic shifts is generated at least in part based on the second set of cyclic shifts and the set of cyclic shift offsets including the first cyclic shift step size, and the third cyclic shift is a cyclic shift in the second set of cyclic shifts.

[0311] Aspect 24: The method according to any one of aspects 22 to 23, wherein the third cyclic shift is the same as the first cyclic shift.

[0312] Aspect 25: The method according to any one of Aspects 22 to 24, wherein sending the conflict resolution message comprises: sending the conflict resolution message indicating one or more random access channel timings for the first UE to send a second response message.

[0313] Aspect 26: The method according to any one of Aspects 22 to 25, wherein sending the control message comprises: sending the control message indicating a cyclic shift monitoring range, the response message being used for the first UE at least in part based on the third cyclic shift and the monitoring range.

[0314] Aspect 27: The method according to any one of Aspects 15 to 26, wherein sending the response message comprises: sending the response message based on a comparison between the first random access message and the second random access message, the comparison being based at least in part on previous conflict information associated with the serving cell, multipath information associated with the serving cell, or a combination thereof.

[0315] Aspect 28: The method according to any one of Aspects 15 to 27, wherein the RTT is the maximum RTT of the serving cell.

[0316] Aspect 29: A UE for wireless communication, the UE comprising: one or more memories storing processor-executable code; and one or more processors coupled to the one or more memories and capable of operating individually or jointly to execute the code to cause the UE to perform a method according to any one of Aspects 1 to 14.

[0317] Aspect 30: A UE for wireless communication, the UE comprising: at least one component for performing the method according to any one of aspects 1 to 14.

[0318] Aspect 31: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform the method according to any one of aspects 1 to 14.

[0319] Aspect 32: A network entity for wireless communication, the network entity comprising: one or more memories storing processor-executable code; and one or more processors coupled to the one or more memories and capable of operating individually or jointly to execute the code, so that the network entity performs a method according to any one of aspects 15 to 28.

[0320] Aspect 33: A network entity for wireless communication, the network entity comprising at least one component for performing the method according to any one of aspects 15 to 28.

[0321] Aspect 34: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform the method according to any one of aspects 15 to 28.

[0322] It should be noted that the methods described herein describe possible specific implementations, and the operations and steps can be rearranged or otherwise modified, and other specific implementations are also possible. Furthermore, aspects from two or more of these methods can be combined.

[0323] While aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes, and the terms LTE, LTE-A, LTE-A Pro, or NR may be used in most of the description, the techniques described herein are also applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described are applicable to a variety of other wireless communication systems, such as Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0324] The information and signals described herein can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0325] The various exemplary blocks and components described herein can be implemented or performed using a general-purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic unit, discrete hardware component, or any combination thereof, designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in alternative embodiments, a processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration). Any function or operation described herein that can be performed by a processor may be performed by multiple processors capable of performing the described functions or operations individually or jointly.

[0326] The functions described herein can be implemented using hardware, software executed by a processor, firmware, or any combination thereof. When implemented using software executed by a processor, the functions can be stored as one or more instructions or code on a computer-readable medium or transmitted using one or more instructions or code on a computer-readable medium. Other examples and specific implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. Features implementing the functions can also be physically located in various locations, including portions distributed such that the functions are implemented in different physical locations.

[0327] Computer-readable media includes both non-transitory computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. Non-transitory storage media can be any available medium accessible by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compressed optical disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code components in the form of instructions or data structures, and accessible by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Furthermore, any connection is appropriately referred to as computer-readable media. 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 coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used herein, disks and optical discs include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks can magnetically reproduce data, and optical discs can optically reproduce data using lasers. Combinations of the above are also included within the scope of computer-readable media. Any function or operation described herein that can be performed by memory can be performed by multiple memories capable of performing the described function or operation individually or jointly.

[0328] As used herein, the word "or" in a list of items (e.g., a list of items accompanied by phrases such as "at least one of" or "one or more of") in the claims indicates an inclusive list, such that a list of at least one of, for example, 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). Furthermore, 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" could be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0329] As used herein, including in claims, the article “a” preceding a noun is open-ended and is understood to refer to “at least one” or “one or more” of those nouns. Therefore, the terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. For example, where a claim enumerates “components” performing one or more functions, each of the individual functions may be performed by a single component or by any combination of multiple components. Thus, the term “component” having a characteristic or performing a function may refer to “at least one of one or more components” having a particular characteristic or performing a particular function. Subsequent references to a component introduced with the article “a” using the terms “the” or “the” can refer to any or all of the one or more components. For example, a component introduced with the article “a” can be understood to mean “one or more components,” and subsequent reference to “the component” in a claim can be understood as equivalent to referring to “at least one of the one or more components.” Similarly, subsequent references to a component introduced with the terms “the” or “the” as “one or more components” can refer to any or all of the one or more components. For example, reference to "the one or more components" in the subsequent claims can be understood as equivalent to reference to "at least one of the one or more components".

[0330] The term "determine" encompasses a variety of actions, and therefore, "determine" can include calculation, computation, processing, derivation, investigation, lookup (such as by searching in a table, database, or other data structure), identification, and similar actions. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in memory), etc. Moreover, "determine" can include parsing, acquiring, selecting, choosing, creating, and other similar actions.

[0331] In the accompanying drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by adding a dash after the reference numeral and a second reference numeral to differentiate them. If only the first reference numeral is used in the description, the description can be applied to any of the similar components having the same first reference numeral, regardless of the second or other subsequent reference numerals.

[0332] The description herein, illustrated with reference to the accompanying drawings, describes an example configuration and does not represent all achievable examples or those within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration," not "preferred" or "advantageous over other examples." The detailed description includes specific details used to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concept of the described examples.

[0333] The description herein is provided to enable those skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be 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 this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A user equipment (UE), the user equipment (UE) comprising: One or more memories, wherein the one or more memories store processor-executable code; and One or more processors, coupled to one or more memories and capable of operating individually or jointly to execute the code to enable the UE: Receive control messages indicating the first set of cyclically shifted random access messages, including random access preambles; as well as The random access message is sent based on the cyclic shift in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of the UE.

2. The UE of claim 1, wherein the cyclic shift is at least partially based on a cyclic shift offset less than the RTT, and wherein, In order to receive the control message indicating the first set of cyclic shifts, the one or more processors can operate individually or jointly to execute the code to cause the UE to: The control message receives a second set of cyclic shifts and a set of cyclic shift offsets including the first cyclic shift step size. as well as The first set of cyclic shifts is generated at least in part based on the second set of cyclic shifts and the set of cyclic shift offsets.

3. The UE of claim 1, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the UE to: The cyclic shift is selected from the first set of cyclic shifts, the first set of cyclic shifts having a consistent cyclic shift step size smaller than the RTT.

4. The UE of claim 1, wherein the control message indicates a cyclic shift monitoring range based at least in part on the RTT, and the one or more processors are also capable of operating individually or jointly to execute the code to cause the UE to: Receive a first response message indicating the root and second cyclic shift of the random access preamble, wherein the first response message is used for the UE at least in part based on the second cyclic shift being spaced from the cyclic shift by a distance smaller than the cyclic shift monitoring range; and The second response message is sent based at least in part on the first response message.

5. The UE of claim 4, wherein the first set of cyclic shifts is generated at least in part based on the second set of cyclic shifts and the set of cyclic shift offsets including the first cyclic shift step size, and the second cyclic shift is a cyclic shift in the second set of cyclic shifts.

6. The UE according to claim 5, wherein the first response message includes a second random access message, and wherein, In order to receive the first response message, the one or more processors can operate individually or jointly to execute the code to enable the UE to: Receive the second random access message, which indicates a timing advance offset for sending the second response message.

7. The UE of claim 6, wherein the cyclic shift is at least partially based on a cyclic shift offset less than the RTT, wherein the second response message includes a third random access message, and wherein, In order to send the second response message, the one or more processors can operate individually or jointly to execute the code to enable the UE to: The third random access message is sent at least in part based on the timing advance offset and the cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

8. The UE of claim 4, wherein the second cyclic shift is spaced apart from the cyclic shift at least in part based on the propagation delay between the UE and the network entity associated with the serving cell.

9. The UE of claim 8, wherein the second response message includes a third random access message, and wherein, In order to send the second response message, the one or more processors can operate individually or jointly to execute the code to enable the UE to: The third random access message is sent at least in part based on a timing advance offset, the timing advance offset corresponding to the difference between the second cyclic shift and the cyclic shift, wherein the third random access message is sent at least in part based on the difference being less than the cyclic shift monitoring range.

10. The UE of claim 9, wherein the cyclic shift is at least partially based on a cyclic shift offset less than the RTT, and wherein, In order to send the third random access message, the one or more processors can operate individually or jointly to execute the code to cause the UE to: The third random access message is sent at least in part based on the timing advance offset and the cyclic shift offset, wherein the timing advance offset is greater than or equal to the cyclic shift offset.

11. The UE of claim 4, wherein the size of the cyclic shift monitoring range is the same as the size of the first cyclic shift step of the first set of cyclic shifts.

12. The UE of claim 4, wherein the size of the cyclic shift monitoring range is greater than or equal to the first cyclic shift step size of the first set of cyclic shifts.

13. The UE of claim 4, wherein the first response message includes a conflict resolution message, and wherein, In order to receive the first response message, the one or more processors can operate individually or jointly to execute the code to enable the UE to: Receive the conflict resolution message indicating one or more random access channel timings for sending the second response message, wherein the second response message is sent via one of the one or more random access channel timings.

14. The UE of claim 1, wherein the RTT corresponds to a threshold RTT supported by the serving cell.

15. A network entity, the network entity comprising: One or more memories, wherein the one or more memories store processor-executable code; and One or more processors, coupled to one or more memories and capable of operating individually or jointly to execute the code to enable the network entity: A control message is sent to a first user equipment (UE) and a second UE, indicating a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of the network entity. The first random access message is received from the first UE from one or more random access messages, the first random access message being associated with a first cyclic shift of the first set at least in part based on cyclic shift; The second random access message is received from the one or more random access messages from the second UE, the second random access message being associated with a second cyclic shift of the first set at least in part based on cyclic shift; as well as The response message for the first UE is sent at least in part based on the control message, the first cyclic shift, and the second cyclic shift.

16. The network entity of claim 15, wherein the response message includes a random access response message, and wherein, In order to send the response message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: It is determined that the first random access message and the second random access message are separable in the cyclic shift domain; as well as Send the random access response message, which includes a timing advance offset and an indication of a third cyclic shift based at least in part on the first cyclic shift.

17. The network entity according to claim 16, wherein, In order to send the control message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: The control message indicating the cyclic shift monitoring range is sent, and the random access response message is used for the first UE at least in part based on the third cyclic shift distance from the first cyclic shift within the cyclic shift monitoring range.

18. The network entity of claim 16, wherein the first set of cyclic shifts is generated at least in part based on a second set of cyclic shifts and a set of cyclic shift offsets including the first cyclic shift step size, and the third cyclic shift is a cyclic shift in the second set of cyclic shifts.

19. The network entity of claim 18, wherein the one or more processors are further capable of operating individually or jointly to execute the code to cause the network entity to: The timing advance offset is calculated at least in part based on the third cyclic shift.

20. The network entity of claim 16, wherein the third cyclic shift is the same as the first cyclic shift.

21. The network entity of claim 20, wherein the random access response message includes a Media Access Control Element (MAC-CE).

22. The network entity of claim 15, wherein the response message includes a conflict resolution message, and wherein, In order to send the response message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: It is determined that the first cyclic shift is the same as the second cyclic shift and that the first random access message and the second random access message are received at the same time; and The conflict resolution message for the first UE is sent at least in part based on the control message and the determination, the conflict resolution message including an indication of a third cyclic shift at least in part based on the first cyclic shift.

23. The network entity of claim 22, wherein the first set of cyclic shifts is generated at least in part based on a second set of cyclic shifts and a set of cyclic shift offsets including the first cyclic shift step size, and the third cyclic shift is a cyclic shift in the second set of cyclic shifts.

24. The network entity of claim 22, wherein the third cyclic shift is the same as the first cyclic shift.

25. The network entity according to claim 22, wherein, In order to send the conflict resolution message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: Send the conflict resolution message indicating one or more random access channel timings for the first UE to send the second response message.

26. The network entity according to claim 22, wherein, In order to send the control message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: The control message indicating the cyclic shift monitoring range is sent, and the response message is used for the first UE based at least in part on the third cyclic shift and the monitoring range.

27. The network entity according to claim 15, wherein, In order to send the response message, the one or more processors can operate individually or jointly to execute the code to enable the network entity to: The response message is sent based on a comparison between the first random access message and the second random access message, the comparison being at least in part based on previous conflict information associated with the serving cell, multipath information associated with the serving cell, or a combination thereof.

28. The network entity of claim 15, wherein the RTT is the maximum RTT of the serving cell.

29. A method for conducting wireless communication at a user equipment (UE), the method comprising: Receive control messages indicating the first set of cyclically shifted random access messages, including random access preambles; as well as The random access message is sent based on the cyclic shift in the first set of cyclic shifts, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of the UE.

30. A method for conducting wireless communication at a network entity, the method comprising: A control message is sent to a first user equipment (UE) and a second UE, indicating a first set of cyclic shifts for sending one or more random access messages, the first set of cyclic shifts being associated with a first cyclic shift step size less than the round-trip time (RTT) associated with the serving cell of the network entity. The first random access message is received from the first UE from one or more random access messages, the first random access message being associated with a first cyclic shift of the first set at least in part based on cyclic shift; The second random access message is received from the one or more random access messages from the second UE, the second random access message being associated with a second cyclic shift of the first set at least in part based on cyclic shift; as well as The response message for the first UE is sent at least in part based on the control message, the first cyclic shift, and the second cyclic shift.

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