HARQ feedback associated with pssch transmission

Description

1 / 62 HARQ FEEDBACK ASSOCIATED WITH PSSCH TRANSMISSION TECHNICAL FIELD

[0001] This disclosure relates to wireless communications and, more specifically, to user equipment, a base station, apparatus and methods for hybrid automatic repeat request feedback (HARQ) associated with a physical side link shared channel (PSSCH) transmission. BACKGROUND

[0002] A wireless communications system may include one or multiple network communication devices, such as base stations, which may also be known as eNodeB (eNB), next-generation NodeB (gNB), or other suitable terminology. Each network communication device, such as a base station, may support wireless communications to one or multiple user communication devices, which may also be known as user equipment (UE) or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing wireless communication system features (e.g., timing features (e.g., symbols, slots, subframes, frames, or the like) or frequency features (e.g., subcarriers, carriers).In addition, the wireless communications system can support wireless communications in various radio access technologies, including third-generation (3G) radio access technology, fourth-generation (4G) radio access technology, fifth-generation (5G) radio access technology, and other suitable radio access technologies besides 5G (e.g., sixth generation (6G)).

[0003] A Study Item (SID) Version (Rel)-18 on side link (SL) evolution was approved, which includes the objective of providing SL support in unlicensed spectrum, for example, to study and specify SL support in unlicensed spectrum for mode 1 and mode 2, where Uu operation Petition 870250088252, dated 09 / 29 / 2025, page 10 / 91 2 / 62 for mode 1 is limited to licensed spectrum only. In an unlicensed SL operation, gNB does not perform type 1 channel access to initiate and share a channel occupancy, nor type 2 channel access to share an initiated channel occupancy, nor semistatic channel access procedures to access an unlicensed channel. SUMMARY

[0004] This disclosure relates to user equipment, a base station, apparatus and methods for HARQ feedback associated with a PSSCH transmission. In a first aspect of the solution, a first UE may include a processor; and a transceiver coupled to the processor, wherein the processor is configured to receive, via the transceiver and from a second UE, a physical side link shared channel (PSSCH) transmission; and determine whether the PSSCH transmission is within a reference duration of a channel occupation time (COT), wherein a hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.By implementing the modalities of this disclosure, an adjustment of a contention window size based on HARQ feedback in the unlicensed SL (SL-U) band can be supported, and a PSFCH transmission for which the adjustment of the contention window size can be guaranteed.

[0005] In some implementations of the method and devices described in this document, the determination of whether the PSSCH transmission is within the reference duration may be based on one of the following: an indicator showing whether the PSSCH transmitted by the second UE is within the reference duration; an initial symbol of the PSSCH transmission within a PSSCH slot; or a time pattern configured for a PSSCH demodulation reference signal (DMRS) associated with the PSSCH transmission. Petition 870250088252, dated 09 / 29 / 2025, p. 11 / 91 3 / 62

[0006] In some implementations of the method and devices described in this document, the indicator can be transmitted via one of the following: a first-stage side link control (SCI) information; a second-stage SCI; a medium access control (MAC) element.

[0007] In some implementations of the method and devices described in this document, a reference duration location may be one of the following: a first PSSCH transmission slot within the COT, wherein the first slot starts from a first candidate starting position within the COT slot; a first PSSCH transmission slot within the COT, wherein the first slot starts from a first candidate starting position or a second candidate starting position within the COT slot; or a first slot and a second slot adjacent to the first PSSCH transmission slot, wherein the first slot starts from a second candidate starting position within the COT slot.

[0008] In some implementations of the method and devices described in this document, the determination of whether PSSCH transmission is within the reference duration can be based on the location of the reference duration within the COT and the location of the PSSCH transmission.

[0009] In some implementations of the method and devices described in this document, the determination of the PSSCH transmission location may be based on one of the following: a channel access priority class (CAPC) value used to initiate the COT and a remaining COT duration; or a total COT duration and a remaining COT duration.

[0010] In some implementations of the method and devices described in this document, determining the location of the PSSCH transmission may involve determining a final COT slot based on the remaining COT duration and a slot carrying information on the remaining duration; determining a Petition 870250088252, dated 09 / 29 / 2025, page 12 / 91 4 / 62 initial COT slot based on the final slot and total COT duration; and determination of the PSSCH transmission location based on the initial slot.

[0011] In some implementations of the method and devices described in this document, the location of the reference duration can be configured by means of one of the following: a radio resource control (RRC) selection; a system information block (SIB); a master information block (MIB); or a MAC CE.

[0012] In some implementations of the method and devices described in this document, the first UE may determine that a PSFCH transmission carrying a HARQ acknowledgment (ACK) feedback associated with the PSSCH transmission is of a higher priority level; and transmit, through the transceiver and to the second UE, the PSFCH transmission with the higher priority level.

[0013] In some implementations of the method and devices described in this document, if the first UE performs multiple transmissions, the PSFCH transmission may be the last to be discarded due to a transmission limitation; if the first UE transmits and receives multiple transmissions, the PSFCH transmission may be the last to be discarded due to a transmission limitation; and if there are multiple PSFCH occasions, the first UE may perform at least one PSFCH transmission.

[0014] In a second aspect of the solution, a second UE described in this document may include a processor; and a transceiver coupled to the processor, wherein the processor may be configured to transmit, via the transceiver and to one or more first UEs, a PSSCH transmission; and determine a contention window size in response to a failure to receive a HARQ feedback from one or more first UEs. Petition 870250088252, dated 09 / 29 / 2025, p. 13 / 91 5 / 62

[0015] In some implementations of the method and devices described in this document, the second UE may transmit, to one or more first UEs, an indicator showing whether the PSSCH transmission is within a reference duration.

[0016] In some implementations of the method and devices described in this document, the indicator can be transmitted via one of the following: a first SCI; a second-stage SCI; or a MAC CE.

[0017] In some implementations of the method and devices described in this document, the second UE can determine the contention window size in the case of a HARQ ACK feedback corresponding to the PSSCH transmission being enabled, wherein the HARQ ACK feedback indicates that a first UE must transmit an ACK if the first UE correctly decodes a side-link shared channel transport block (SL-SCH), and the first UE must transmit a negative acknowledgment (NACK) if the first UE has detected the SL-SCH TB, but the first UE fails to decode the SL-SCH TB.

[0018] In some implementations of the method and devices described in this document, HARQ ACK feedback may be enabled in response to one of the following conditions: if the PSSCH transmission is for SL unicast, the HARQ ACK feedback comprising ACK or NACK corresponding to the PSSCH transmission is not received from a target UE of the first one or more UEs; if the PSSCH transmission is for SL groupcast, the HARQ ACK feedback comprising ACK or NACK corresponding to the PSSCH transmission is not received from a target UE of the first one or more UEs; or if the PSSCH transmission is for SL groupcast, the ratio of the number of HARQ feedbacks received to the number of the first one or more UEs within the groupcast is below a threshold ratio. Petition 870250088252, dated 09 / 29 / 2025, p. 14 / 91 6 / 62

[0019] In some implementations of the method and devices described in this document, the second UE may fail to receive HARQ ACK feedback, and the second UE may do one of the following: increase the containment window size for each CAPC; keep the containment window size unchanged; or keep the containment window size unchanged until HARQ feedback is received on a subsequent occasion of a PSFCH transmission, and adjust the containment window size based on the HARQ ACK feedback received in the PSFCH transmission.

[0020] In some implementations of the method and devices described in this document, a PSFCH transmission carrying a HARQ ACK feedback associated with the PSSCH transmission is determined to be of higher priority level by at least one UE of the first one or more UEs, and the second UE fails to receive the HARQ feedback associated with multiple PSFCH instances towards the PSSCH transmission within a reference duration, and the second UE may increase the contention window size for each CPAC.

[0021] In a third aspect of the solution, a base station (BS) may comprise: a processor; and a transceiver coupled to the processor, wherein the processor is configured to transmit, via the transceiver and to a UE, a location of a reference duration to a COT, wherein a HARQ feedback associated with a PSSCH transmission within the reference duration is used to determine a contention window size.

[0022] In some implementations of the method and devices described in this document, the PSSCH transmission may be for SL groupcast, and the BS may transmit, to the UE, a ratio of a number of HARQ feedbacks corresponding to the PSSCH transmission and a number of UEs within the SL groupcast. Petition 870250088252, dated 09 / 29 / 2025, p. 15 / 91 7 / 62

[0023] In a fourth aspect of the solution, a processor for wireless communication may comprise: at least one memory; and a controller coupled to at least one memory and configured to make the controller: receive, from a second UE, a PSSCH transmission; and determine whether the PSSCH transmission is within a reference duration of a COT, wherein a HARQ feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.

[0024] In a fifth aspect of the solution, a processor for wireless communication may comprise: at least one memory; and a controller coupled to at least one memory and configured to make the controller: transmit, to the first one or more UEs, a PSSCH transmission; and determine a contention window size in response to a failure to receive a HARQ feedback from the first one or more UEs.

[0025] In a sixth aspect of the solution, a processor for wireless communication may comprise: at least one memory; and a controller coupled to at least one memory and configured to make the controller: transmit, to a UE, a location of a reference duration for a COT, wherein a HARQ feedback associated with a PSSCH transmission within the reference duration is used to determine a contention window size.

[0026] In a seventh aspect of the solution, a method performed by a first UE described in this document may include receiving, from a second UE, a PSSCH transmission; and determining whether the PSSCH transmission is within a reference duration of a COT, wherein a HARQ feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.

[0027] In an eighth aspect of the solution, a method implemented by a second UE described in this document may include Petition 870250088252, dated 09 / 29 / 2025, p. 16 / 91 8 / 62 transmit, to one or more first UEs, a PSSCH transmission; and determine a contention window size in response to a failure to receive HARQ feedback from one or more first UEs.

[0028] In a ninth aspect of the solution, a method implemented by a base station described in this document may include transmitting, to a UE, a location of a reference duration for a COT, wherein a HARQ feedback associated with a PSSCH transmission within the reference duration is used to determine a contention window size.

[0029] It is important to emphasize that the summary section is not intended to identify key or essential features of the modalities of this disclosure, nor to be used to limit the scope of this disclosure. Other features of this disclosure will become easily understandable through the description below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 illustrates an example of a wireless communications system that supports PSFCH transmission in accordance with aspects of the present disclosure.

[0031] Figures 2A and 2B illustrate exemplary signaling procedures for a PSFCH transmission in accordance with aspects of this disclosure.

[0032] Figure 3 illustrates multiple instances of exemplary PSFCH in the time domain associated with a PSSCH transmission in accordance with aspects of the present disclosure.

[0033] Figure 4 illustrates multiple instances of exemplary PSFCH in the frequency domain associated with a PSSCH transmission in accordance with aspects of the present disclosure.

[0034] Figure 5 illustrates exemplary reference durations within a COT according to aspects of the present disclosure.

[0035] Figures 6 - 8 illustrate examples of devices for Petition 870250088252, dated 09 / 29 / 2025, p. 17 / 91 9 / 62 HARQ feedback associated with a PSSCH transmission in accordance with aspects of this disclosure.

[0036] Figures 9-11 illustrate examples of processors for HARQ feedback associated with a PSSCH transmission according to aspects of the present disclosure.

[0037] Figures 12-14 illustrate method flowcharts for HARQ feedback associated with a PSSCH transmission in accordance with aspects of the present disclosure. DETAILED DESCRIPTION

[0038] The principles of this disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are described for illustrative purposes only and assist those skilled in the art in understanding and implementing this disclosure, without suggesting any limitation as to its scope. The disclosure described in this document can be implemented in a number of ways beyond those described below.

[0039] In the description and claims that follow, unless defined otherwise, all technical and scientific terms used in this document have the same meaning commonly understood by a person with common knowledge in the field to which this disclosure pertains.

[0040] References in this disclosure to “a modality,” “an example modality,” “a modality,” “some modalities,” and the like indicate that the modality(ies) described may include a specific feature, structure, or characteristic, but it is not necessary that every modality includes the specific feature, structure, or characteristic. Furthermore, such sentences do not necessarily refer to the same modality(ies). Moreover, when a specific feature, structure, or characteristic is described in connection with a modality, it is understood that it is within the knowledge of a person skilled in the art to affect such feature, structure, or characteristic. Petition 870250088252, dated 09 / 29 / 2025, p. 18 / 91 10 / 62 characteristic in connection with other modalities, whether explicitly described or not.

[0041] It should be understood that, although the terms “first” and “second” or similar terms may be used in this document to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may also be referred to as a second element, and similarly, a second element may also be referred to as a first element, without departing from the scope of the modalities. As used in this document, the term and / or includes any and all combinations of one or more of the terms listed.

[0042] The terminology used in this document is intended only for the description of specific modalities and is not intended to limit exemplary modalities. As used in this document, the singular forms a, an and the should also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms includes, comprising, has, having, includes and / or including, when used in this document, specify the presence of the stated resources, elements and / or components etc., but do not preclude the presence or addition of one or more other resources, elements, components and / or combinations thereof.

[0043] As used in this document, the term communication network refers to a network that follows any suitable communication standards, such as 5G NR, Long Term Evolution (LTE), LTE Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), and so on. Furthermore, communications between a terminal device and a network device on the communication network may be carried out according to any generation communication protocols. Petition 870250088252, dated 09 / 29 / 2025, page 19 / 91 11 / 62 suitable, including, but not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols and / or any other protocols currently known or to be developed in the future. The modalities of this disclosure may be applied to various communication systems. Given the rapid development in communications, there will also be future-type communication technologies and systems into which this disclosure may be incorporated. This should not be seen as limiting the scope of this disclosure only to the systems mentioned above.

[0044] As used in this document, the term network device generally refers to a node in a communication network through which a terminal device can access the communication network and receive services from it. The network device may refer to a base station (BS) or an access point (AP), for example, a Node B (NodeB or NB), a radio access network (RAN) node, an evolved NodeB (eNodeB or eNB), an NR NB (also known as gNB), a remote radio unit (RRU), a radio head (RH), a V2X (vehicle-to-everything) communication infrastructure device, a transmit and receive point (TRP), a receive point (RP), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low-power node such as a femto-BS, a pico-BS, and so on, depending on the terminology and technology applied.

[0045] As used in this document, the term terminal device generally refers to any end device that is capable of wireless communication. By way of example, and not limitation, a terminal device may also be called a communication device, a user equipment (UE), an end-user device, a subscriber station (SS), an unmanned aerial vehicle (UAV), a Petition 870250088252, dated 09 / 29 / 2025, page 20 / 91 12 / 62 portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smartphone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a laptop computer, a desktop computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, laptop embedded equipment (LEE), laptop mounted equipment (LME), a USB dongle, a smart device, wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone,A medical device (e.g., a remote surgery device), an industrial device (e.g., a robot and / or other wireless devices operating in industrial and / or automated processing chain contexts), a consumer electronic device, a device operating in commercial and / or industrial wireless networks, and the like. In the following description, the terms: terminal device, communication device, terminal, “user equipment” and UE, may be used interchangeably.

[0046] For new radio in unlicensed band (NR-U), the maximum Nrb transmission bandwidth configuration for frequency 1 (FR1) (450 - 7125 MHz) is shown in Table 1. Table 1 SCS (kHz) 5 MHz 10 MHz 1 5 MHz 20 MHz 25 MHz 30 MHz 40 MHz 50 MHz 60 MHz 80 MHz 100 MHz NRB NRB NRB NRB NRB NRB NRB NRB NRB NRB NRB Petition 870250088252, dated 09 / 29 / 2025, page 21 / 91 13 / 62 15 25 52 79 106 133

[160] 216 270 N / DN / DN / D 30 11 24 38 51 65

[78] 106 133 162 217 273 60 N / A 11 18 24 31

[38] 51 65 79 107 135

[0047] In technical specification (TS) 37.213, there are two CAPC tables defined separately for downlink m (DL) and uplink (UL), with differences in the p values. CW T,max,p , uimcot,pe sizes start a COT for transmission CAPC value according to the channel access procedure start a COT for transmission CAPC value according to the channel access procedure shown below. allowed. When a gNB intends to perform DL, it must determine a Table 2 before performing type 1. When a UE intends to perform UL, it must determine a Table 3 before performing type 1. Tables 2 and 3 are Table 2 Channel access priority class for DL Channel access priority class (p) mp CW minp CW max,p T . m cot, p Allowed CWp sizes 1 1 3 7 2 ms {3,7} 2 1 7 15 3 ms {7,15} 3 3 15 63 8 or 10 ms {15,31,63} 4 7 15 1023 8 or 10 ms {15, 31, 63, 127, 255, 511, 1023} Table 3 Channel access priority class for UL Priority class of mp CW minp CW max, p T, ulm cot, p allowed sizes of CWp Petition 870250088252, dated 09 / 29 / 2025, page 22 / 91 14 / 62 Channel access (P) 1 2 3 7 2 ms {3,7} 2 2 7 15 4 ms {7,15} 3 3 15 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023} 4 7 15 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023} NOTE 1: For p = 3,4, Tulmcot'p = 10ms if the top layer parameter 'absentOfAnyOtherTechnology-r14' indicates Th TRUE, otherwise, ulmcot'p = 6ms. NOTE 2: When ulm cot'p = 6 ms, the time can be increased to 8 ms by inserting one or more gaps. The minimum duration of a gap should be 100 ps. The maximum duration before the inclusion of any gap should be 6 ms.

[0048] As specified in 3GPP NR-U, the size of a contention window can be adjusted based on the Hybrid Automatic Repeat Request (ARQ) acknowledgments received from a transmitter during a reference interval (also known as reference duration), which covers the start of COT. For each Hybrid ARQ report received, the contention window (CW) is (approximately) doubled up to the maximum CW limit if a negative Hybrid ARQ is received. For a positive Hybrid ARQ acknowledgment, the contention window is reset to its minimum value, CW = CWmin.

[0049] As seen above, the motivation for this procedure is to be less aggressive in the use of the channel when transmissions are unsuccessful, which is probably due to collisions with other transmissions and therefore an indication of a highly loaded system. The intention of considering only acknowledgments at the beginning of the COT is that a negative acknowledgment Petition 870250088252, dated 09 / 29 / 2025, page 23 / 91 15 / 62 for the first transmission in a COT can be triggered by a collision, in which case the containment window size must be updated, while any subsequent negative acknowledgments in the COT are not due to collisions and therefore should not affect the containment window size.

[0050] For groupcast transmission to SL, that is, an SL transmission directed to a group of receiving devices, there are two options for hybrid ARQ feedback. The first option is NACK-only feedback. A receiving device provides NACK feedback if it detected the presence of an SL-SCH transport block from the 1st and 2nd stage SCI, but failed to decode the transport block. If the device correctly decoded the SL-SCH transport block (TB), it does not provide any hybrid ARQ feedback.

[0051] With option one, the receiving UEs (Rx) of a transmission share a resource to send their NACK-only feedback. Thus, with option one, a transmitting UE (Tx) cannot identify which Rx UEs sent NACK feedback. If a TX UE receives at least one NACK feedback with option one, it will be aware that at least one RX UE within the required communication range did not correctly decode the transmission. Furthermore, if a TX UE receives no response with option one, it will not be able to distinguish whether the RX UEs within the required communication range successfully received the transmission or whether some did not successfully decode the corresponding 1st stage SCI.

[0052] The second option is ACK / NACK feedback. A receiving device provides ACK feedback if it has correctly decoded an SL-SCH TB. It provides NACK feedback if it has detected the presence of the SL-SCH TB from the 1st and 2nd stage SCI, but has failed to decode it. Petition 870250088252, dated 09 / 29 / 2025, page 24 / 91 16 / 62 the TB.

[0053] With option two, each UE RX sends its ACK / NACK feedback on a separate resource. Conversely, a UE TX can distinguish the HARQ feedback from the UE RXs with option two. This allows the UE TX to perform a customized retransmission for specific UE RXs. With option two, if a UE TX does not receive a response on the feedback resource corresponding to a given UE RX, it will know that the UE RX did not successfully decode the corresponding 1st stage SCI. Consequently, option two allows for greater reliability in transmissions.

[0054] Therefore, how to support CW tuning based on HARQ-ACK feedback in SL-U is an open question. In SL-U 3GPP, it was agreed to tune a CW based on HARQ-ACK ACK / NACK feedback (if available) corresponding to the PSSCH at the reference duration. The motivation behind this is to be less aggressive in channel usage when PSSCH transmission is unsuccessful, which is likely due to collisions with other transmissions. However, there are still issues to be resolved to complete the solution for supporting CW tuning based on HARQ-ACK feedback.

[0055] For example, the case where a PSSCH UE Tx does not receive HARQ-ACK feedback has not been discussed. If the PSSCH UE Tx does not receive HARQ-ACK feedback from a target Rx UE, the UE Tx cannot distinguish whether the Rx UE fails to transmit from the PSSCH due to a listen-before-talk (LBT) failure (indicating a highly loaded system) or whether the Rx UE proactively interrupts the transmission from the PSSCH for some reason (e.g., due to transmission capacity limitations). In this case, how to perform CW tuning must be clarified for the UE Tx.

[0056] As another example, the definition and determination of the reference duration (interval) are not clear. Duration of Petition 870250088252, dated 09 / 29 / 2025, p. 25 / 91 17 / 62 reference and reference interval can be used interchangeably. The reference duration covers the start of the COT. In SL-U, up to two candidate start positions can be supported for PSSCH / PSCCH transmission. Therefore, how to define the reference duration needs clarification. Furthermore, it also needs clarification on how to determine if a PSSCH transmission is within a reference duration for a PSSCH UE Rx, and subsequently, how the PSSCH UE Rx can determine the priority level of the PSSCH corresponding to the PSSCH, in order to increase the possibility of successful HARQ-ACK feedback transmission.

[0057] Therefore, some embodiments of the present disclosure propose a solution for hybrid automatic repeat request (HARQ) feedback associated with a physical side link shared channel (PSSCH) transmission, particularly to support CW tuning based on HARQ-ACK feedback in SL-U. For the PSSCH UE TX, it can provide UE TX procedures for CW tuning when HARQ-ACK feedback is not received, in case there is no mechanism to guarantee the transmission of the associated PSSCH. For the PSSCH UE RX, it can provide a mechanism to guarantee the transmission of the PSSCH, on which CW tuning is based. The mechanism may comprise a location (or definition) of the reference duration and information to determine if a PSSCH is within a reference duration, and procedures in a PSSCH UE RX to prioritize the transmission of the PSSCH towards the PSSCH within a reference duration.By implementing the modalities of this disclosure, an adjustment of a contention window size based on HARQ feedback in SL-U can be supported, and a PSFCH transmission for which the adjustment of the contention window size can be guaranteed.

[0058] Aspects of this disclosure are described in Petition 870250088252, dated 09 / 29 / 2025, page 26 / 91 18 / 62 context of a wireless communications system.

[0059] Figure 1 illustrates an example of a wireless communications system 100 that supports PSFCH transmission according to aspects of this disclosure. The wireless communications system 100 may include one or more network entities 102 (also referred to as network equipment (NE)), one or more UEs 104, a core network 106, and a packet data network 108. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE Enhanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as an NR network. In other implementations, the 100 wireless communications system may be a combination of a 4G network and a 5G network, or other suitable radio access technology, including the Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) and IEEE 802.11 standards.16 (WiMAX) and IEEE 802.20. The 100 wireless communications system can support radio access technologies beyond 5G. Furthermore, the 100 wireless communications system can support technologies such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), or Code Division Multiple Access (CDMA), etc.

[0060] One or more network entities 102 may be dispersed over a geographical region to form the wireless communications system 100. One or more of the network entities 102 described in this document may be, include, or be referred to as a network node, a base station, a network element, a radio access network (RAN), a base transceiver station, an access point, a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. A network entity 102 and a UE 104 may communicate via a communication link 110, which may be a wireless or wired connection. Petition 870250088252, dated 09 / 29 / 2025, page 27 / 91 19 / 62 For example, a network entity 102 and a UE 104 can perform wireless communication (e.g., receive signaling, transmit signaling) through a Uu interface.

[0061] A network entity 102 can provide a geographic coverage area 112 for which the network entity 102 can support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area 112. For example, a network entity 102 and a UE 104 can support wireless communication of service-related signals (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or more radio access technologies. In some implementations, a network entity 102 can be mobile, for example, a satellite associated with a non-terrestrial network. In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies can overlap, but the different geographic coverage areas 112 can be associated with different network entities 102.The information and signals described in this document can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0062] One or more UEs 104 (such as UE 104-1 or UE 1042) may be dispersed across a geographic region of the wireless communications system 100. A UE 104 may include or be referred to as a mobile device, a wireless device, a remote device, a remote unit, a handheld device, or a subscriber device, or some other suitable terminology. In some implementations, the UE 104 may be referred to Petition 870250088252, dated 09 / 29 / 2025, p. 28 / 91 20 / 62 as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine-like communication (MTC) device, among other examples. In some implementations, a UE 104 may be stationary in the 100 wireless communications system. In some other implementations, a UE 104 may be mobile in the 100 wireless communications system.

[0063] One or more UEs 104 can be devices in different forms or have different capabilities. Some examples of UEs 104 are illustrated in Figure 1. A UE 104 may be able to communicate with various types of devices, such as network entities 102, other UEs 104, or network equipment (e.g., the core network 106, the packet data network 108, a relay device, an integrated access and backhaul (IAB) node, or other network equipment), as shown in Figure 1. Additionally, or alternatively, a UE 104 may support communication with other network entities 102 or UEs 104, which may act as relays in the wireless communication system 100.

[0064] A UE 104 may also be able to support wireless communication directly with other UE 104s via a communication link 114. For example, a UE 104 may support wireless communication directly with another UE 104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), or cellular-V2X deployments, the communication link 114 may be referred to as a side link. For example, a UE 104 may support wireless communication directly with another UE 104 via a PC5 interface.

[0065] A network entity 102 can support communications Petition 870250088252, dated 09 / 29 / 2025, page 29 / 91 21 / 62 with the core network 106, or with another network entity 102, or both. For example, a network entity 102 can interact with the core network 106 through one or more backhaul links 116 (for example, through an S1, N2, N2 interface or another network). Network entities 102 can communicate with each other through backhaul links 116 (for example, through an X2, Xn interface or another network). In some implementations, network entities 102 can communicate with each other directly (for example, between network entities 102). In some other implementations, network entities 102 can communicate with each other indirectly (for example, through the core network 106). In some implementations, one or more network entities 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC).An ANC can communicate with one or more UEs 104 through one or more other access network transmission entities, which may be called radio heads, smart radio heads, or transmit-receive points (TRPs).

[0066] In some implementations, a 102 network entity can be configured in a disaggregated architecture, which can be configured to utilize a protocol stack distributed physically or logically among two or more 102 network entities, such as an Integrated Access Backhaul Network (IAB), an Open Radio Access Network (O-RAN) (e.g., an O-RAN Alliance-sponsored network configuration), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, a 102 network entity might include one or more of a CU, a DU, a radio unit (RU), an Intelligent RAN Controller (RIC) (e.g., a Near RT(RT) RIC, a Non-RT RIC), a Service Management and Orchestration (SMO) system, or any combination thereof.

[0067] A RU can also be called a radio head, Petition 870250088252, dated 09 / 29 / 2025, page 30 / 91 22 / 62 intelligent radio head, remote radio head (RRH), remote radio unit (RRU), or transmit-receive point (TRP). One or more components of the 102 network entities in a disaggregated RAN architecture may be colocated, or one or more components of the 102 network entities may be located in distributed locations (e.g., separate physical locations). In some implementations, one or more 102 network entities of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)).

[0068] The division of functionality between a CU, a DU, and a RU can be flexible and can support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combinations thereof) are performed in a CU, a DU, or an RU. For example, a functional division of a protocol stack can be employed between a CU and a DU so that the CU can support one or more layers of the protocol stack and the DU can support one or more different layers of the protocol stack. In some implementations, the CU can host higher protocol layer functionality and signaling (e.g., a layer 3 (L3), a layer 2 (L2)) (e.g., Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)).A CU can be connected to one or more DUs or RUs, and the one or more DUs or RUs can host lower protocol layers, such as a layer 1 (L1) (e.g., physical layer (PHY)) or an L2 (e.g., radio link control layer (RLC), medium access control layer (MAC)) functionality and signaling, and each can be at least partially controlled by the CU 160.

[0069] Additionally, or alternatively, a division Petition 870250088252, dated 09 / 29 / 2025, p. 31 / 91 23 / 62 A functional split of the protocol stack can be employed between a DU and a RU so that the DU can support one or more layers of the protocol stack and the RU can support one or more different layers of the protocol stack. The DU can support one or multiple different cells (e.g., through one or more RUs). In some implementations, a functional split between a CU and a DU, or between a DU and an RU, may be within a protocol layer (e.g., some functions for a protocol layer may be performed by a CU, a DU, or an RU, while other protocol layer functions are performed by a different CU, DU, or RU).

[0070] A CU can be further functionally divided into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU can be connected to one or more DUs via a midhaul communication link (e.g., F1, F1-c, F1u), and a DU can be connected to one or more RUs via a fronthaul communication link (e.g., open fronthaul interface (FH)). In some implementations, a midhaul communication link or a fronthaul communication link can be implemented according to an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 102 that are communicating via such communication links.

[0071] The 106 core network can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The 106 core network can be an evolved packet core (EPC) or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), mobility and access management functions (AMF)) and a user plane entity that routes packets or interconnects external networks (e.g., a service gateway (S-GW), a gateway Petition 870250088252, dated 09 / 29 / 2025, page 32 / 91 24 / 62 packet data network (PDN) (P-GW) or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and carrier management (e.g., data carriers, signal carriers, etc.) for one or more UEs 104 served by one or more network entities 102 associated with the core network 106.

[0072] The core network 106 can communicate with the packet data network 108 through one or more backhaul links 116 (for example, through an S1, N2, N2 interface or other network). The packet data network 108 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. A UE 104 may establish a session (for example, a Protocol Data Unit (PDU) session or similar) with the core network 106 through a network entity 102. The core network 106 may route traffic (for example, control information, data, and similar) between the UE 104 and the application server 118 using the established session (for example, the established PDU session). The PDU session can be an example of a logical connection between UE 104 and the core network 106 (for example, one or more network functions of the core network 106).

[0073] In the wireless communications system 100, network entities 102 and UEs 104 can use resources of the wireless communications system 100 (e.g., timing resources (e.g., symbols, slots, subframes, frames, or similar) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, network entities 102 and UEs 104 can support different resource structures. For example, network entities 102 and UEs 104 can support different frame structures. In some implementations, such as in 4G, network entities 102 and UEs 104 can support Petition 870250088252, dated 09 / 29 / 2025, page 33 / 91 25 / 62 a single frame structure. In some other implementations, such as in 5G and other suitable radio access technologies, 102 network entities and 104 UEs may support multiple frame structures (e.g., multiple frame structures). 102 network entities and 104 UEs may support multiple frame structures based on one or more numerologies.

[0074] One or more numerologies may be supported in the 100 wireless communications system, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., μ=2) can be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix.A fourth numerology (e.g., μ=3) can be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., μ=4) can be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0075] A time interval of a resource (for example, a communication resource) can be organized according to frames (also called radio frames). Each frame can have a duration, for example, a duration of 10 milliseconds (ms). In some implementations, each frame can include several subframes. For example, each frame can include 10 subframes, and each subframe can have a duration, for example, a duration of 1 ms. In some implementations, each frame can have the same Petition 870250088252, dated 09 / 29 / 2025, p. 34 / 91 26 / 62 duration. In some implementations, each subframe of a frame may have the same duration.

[0076] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on one or more numerologies supported in the 100 wireless communication system. For example, the first, second, third, fourth, and fifth numerologies (i.e., μ = 0, μ = 1, μ = 2, μ = 3, μ = 4) associated with the respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot can include a number (e.g., quantity) of symbols (e.g., OFDM symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology.For a normal cyclic prefix, a slot can include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot can include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that the reference to a first numerology (e.g., μ=0) associated with a first subcarrier spacing (e.g., 15 kHz) can be used interchangeably between subframes and slots.

[0077] In a 100 wireless communications system, an electromagnetic (EM) spectrum can be divided, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. As an example, a 100 wireless communications system can support one or multiple bands. Petition 870250088252, dated 09 / 29 / 2025, page 35 / 91 27 / 62 operating frequency bands, such as frequency band designations FR1 (410 MHz — 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz — 114.25 GHz), FR4a or FR4-1 (52.6 GHz — 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, network entities 102 and UEs 104 may perform wireless communications in one or more of the operating frequency bands. In some implementations, FR1 may be used by network entities 102 and UEs 104, among other equipment or devices, for cellular communications traffic (e.g., control information, data). In some implementations, FR2 can be used by network entities 102 and UEs 104, among other equipment or devices for short-range, high-data-rate capabilities.

[0078] FR1 can be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 can be associated with a first numerology (e.g., μ=0), which includes a subcarrier spacing of 15 kHz; a second numerology (e.g., μ=1), which includes a subcarrier spacing of 30 kHz; and a third numerology (e.g., μ=2), which includes a subcarrier spacing of 60 kHz. FR2 can be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 can be associated with a third numerology (e.g., μ=2), which includes a subcarrier spacing of 60 kHz; and a fourth numerology (e.g., μ=3), which includes a subcarrier spacing of 120 kHz.

[0079] Figures 2A and 2B illustrate exemplary signaling procedures 200A and 200B for a PSSCH transmission according to aspects of this disclosure. UE 104-1 is also referred to as a first UE or an Rx UE of the PSSCH. UE 1042 is also referred to as a second UE or a Tx UE of the PSSCH. A BS 102 corresponds to network entity 102 in Figure 1. It should be understood that there may be more UEs, including Tx UEs and Rx UEs, related to signaling procedure 200. Petition 870250088252, dated 09 / 29 / 2025, p. 36 / 91 28 / 62

[0080] As shown in Figure 2A, BS 102 transmits (202) a reference duration location 206 to a COT for UE 104-1 and UE 104-2, and / or some other UEs not shown. UE 104-1 receives (205) the location of a reference duration 206 from BS 102. UE 104-2 receives (204) the location of a reference duration 206 from BS 102. In one example, the location of a reference duration 206 for a COT can be configured for UE 104 via at least one of the following: a Master Information Block (MIB) message, a System Information Block (SIB) message, a Radio Resource Control (RRC) signal, a Medium Access Control (MAC) control element (CE), or Downlink Control Information (DCI). Additionally, the location of a reference duration 206 for a COT can be obtained by UE 104 based on pre-configuration, preset, or defined.The location of a 206 reference duration for a COT can be configured, pre-configured, preset, or defined by frequency band (FR), by bandwidth portion (BWP), by carrier, by resource block set (RB), or by resource grouping configuration (RP).

[0081] As shown in Figure 2B, UE 104-2 transmits (212) a PSSCH 214 transmission to UE 104-1. In some embodiments, UE 104-2 may transmit the PSSCH 214 transmission to one or more Rx UEs (i.e., one or more first UEs). UE 104-1 receives (210) the PSSCH 214 transmission from UE 104-2. UE 104-1 determines (216) whether the PSSCH 214 transmission is within a reference duration of a COT. A hybrid automatic repeat request (HARQ) feedback associated with the PSSCH 214 transmission within the reference duration is used to determine a contention window size.

[0082] If UE 104-2 does not receive feedback from HARQ Petition 870250088252, dated 09 / 29 / 2025, p. 37 / 91 29 / 62 of UE 104-1, UE 104-2 determines (218) the size of a containment window. In some example embodiments, if UE 1042 can transmit the PSSCH 214 transmission to one or more Rx UEs, if UE 104-2 does not receive HARQ feedback from one or more Rx UEs, UE 104-2 determines (218) the size of a containment window.

[0083] In some example embodiments, when HARQ-ACK feedback is enabled, if the HARQ-ACK feedback corresponding to the PSSCH 214 transmission (for SL unicast or SL groupcast option two) is not received by a Tx UE from a PSSCH transmission (such as UE 104-2), one of three reasons could be that the PSSCH transmission carrying the HARQ-ACK feedback has failed the PSSCH UE Rx due to an LBT failure. The second reason could be that the PSSCH transmission carrying the HARQ-ACK feedback is dropped by the PSSCH UE Rx due to the low priority level given to the PSSCH in multiple transmissions. The third reason could be that the PSSCH is not received by the target UE Rx due to halfduplex operation.

[0084] In some other exemplary modes, when HARQ-ACK feedback is enabled, the HARQ-ACK ACK / NACK feedback corresponding to the PSSCH for SL unicast on the reference duration for the most recent SL channel occupation may not be received. In some exemplary modes, when HARQ-ACK feedback is enabled, the HARQ-ACK ACK / NACK feedback corresponding to the PSSCH for SL groupcast option two on the reference duration for the most recent SL channel occupation may encounter one of certain conditions, which cause the UE TX (such as the UE 104-2) to determine or adjust the CW size.

[0085] One of the conditions may be that feedback is not received from one or more target Rx UEs. This is reasonable because, in groupcast option two, the Tx UE can distinguish Petition 870250088252, dated 09 / 29 / 2025, p. 38 / 91 30 / 62 the Rx UE according to PSFCH resources. Another condition may be that a ratio is greater than or equal to a (pre-)configured ratio. This ratio can be determined by one minus the ratio between the number of feedbacks received and the number of Rx UEs within the groupcast.

[0086] In some exemplary situations, a UE transmitter (such as the UE 104-2) of the PSSCH transmission may perform CW size adjustment to increase the CW size to the next highest value at each CAPC. This may be due to the assumption that the reason for not receiving feedback is the primary reason. In some exemplary embodiments, a UE transmitter of the PSSCH transmission may perform CW size adjustment to keep the CW size unchanged. This may be due to the assumption that the reason for not receiving feedback is the secondary reason.

[0087] Additionally or alternatively, a Tx UE of the PSSCH transmission may perform CW size adjustment to maintain the CW size unchanged until a HARQ feedback is received on the next PSFCH transmission occasion, and then adjust the CW size according to the HARQ-ACK feedback transmitted by the PSFCH, in case multiple PSFCH occasions are associated with a PSSCH. This may occur because multiple PSFCH occasions are used to increase the reliability of the PSFCH transmission.

[0088] For a better understanding of PSFCH occasions, see Figures 3 and 4. Figure 3 illustrates examples of multiple PSFCH occasions 300 in the time domain associated with a PSSCH transmission, according to aspects of this disclosure. As shown in Figure 3, there are four slots 302, 304, 306, and 308 in a set of resource blocks (RB) 324. A legend 310 represents a PSSCH. A legend 312 represents a PSCCH. A legend 314 represents a PSFCH. A legend 316 represents an automatic gain control (AGC) symbol. A legend 318 represents an association between both. Petition 870250088252, dated 09 / 29 / 2025, page 39 / 91 31 / 62 arrowhead ends. As shown in Figure 3, a PSFCH 320 is associated with slot 302. A PSFCH 322 is associated with slot 302.

[0089] Figure 4 illustrates an example of multiple PSFCH 400 instances in the frequency domain associated with a PSSCH transmission, according to aspects of the present disclosure. As shown in Figure 4, there are three slots 402, 404, and 406 in the RB sets 424 and 426. A legend 410 represents a PSSCH. A legend 412 represents a PSCCH. A legend 414 represents a PSFCH. A legend 416 represents an AGC symbol. A legend 418 represents an association between both ends of the arrow. As shown, a PSFCH 420 is associated with slot 402 in the RB set 426. A PSFCH 422 is associated with slot 402 in the RB set 426.

[0090] Returning to Figure 2, in some example modes, the UE Rx (such as the UE 104-1) can guarantee the transmission of the PSFCH 214 transmission, on which the CW tuning is based. For example, the UE 104-1 can provide a PSFCH for CW tuning with the highest priority level for transmission among multiple PSSCH UE Rx transmissions. Multiple transmissions may comprise one or more PSFCH transmissions, synchronization signal block / physical broadcast channel (SSSB) transmissions, and PSSCH / PSCCH transmissions.

[0091] For slots with two initial candidate symbols for a PSCCH / PSSCH transmission: the location of the 1st initial symbol can be (pre-)configured from {#0, #1, #2, #3, #4, #5, #6} by BWP, and the location of the 2nd initial symbol can be (pre-)configured from {#3, #4, #5, #6, #7} by BWP. By default (if there is no (pre-)configuration), the location of the 1st initial symbol is symbol #0. It can be configured so that, within a slot, the number of symbols used for PSCCH / PSSCH transmission from the 2nd initial symbol is not less than 6. It can be configured so that, within Petition 870250088252, dated 09 / 29 / 2025, page 40 / 91 32 / 62 of a slot, the 2nd initial symbol is later than the 1st initial symbol. A PSCCH / PSSCH transmission starting from the 1st or 2nd initial symbol may have the same final symbol within a slot. It should be noted that the symbol index in a slot is assumed to start at #0. Full-slot PSSCH means that a PSSCH starts at the first candidate initial position within a slot. Partial-slot PSSCH means that a PSSCH starts at the second candidate initial position within a slot.

[0092] For the sake of clear illustration, reference will be made in conjunction with Figure 5. Figure 5 illustrates exemplary reference durations 500 within a COT, according to aspects of the present disclosure. In some exemplary embodiments, the location (or definition) of the reference duration can be determined by the first complete slot for PSSCH transmission within a COT. For example, for a bandwidth part (BWP) where only one initial symbol is supported for PSSCH, slot 502 in the RB set 524 and COT 530 shown in Figure 5 can be determined as an example of the reference duration. In another example, for a bandwidth part (BWP) where two initial symbols are supported for PSSCH, slot 504 in the RB set 526 and COT 532 shown in Figure 5 can be determined as an example of the reference duration.

[0093] The location (or definition) of the reference duration can be determined by the first slot for PSSCH transmission, which starts in a partial or complete slot within a COT. As an example, as shown in Figure 5, slot 502 in the RB set 526 and in COT 532, or slot 502 in the RB set 524 and in COT 530 can be determined as an example of the reference duration.

[0094] Additionally or alternatively, the location (or definition) of the reference duration can be determined by the first partial slot and the next full slot for Petition 870250088252, dated 09 / 29 / 2025, page 41 / 91 33 / 62 PSSCH transmission within a COT. For BWP where two initial symbols are supported for PSSCH transmission, and the COT starts from the second initial symbol of the first slot. Slots 502 and 504 in the RB 526 set and in COT 532 can be determined as an example of the reference duration.

[0095] For example, the information to determine if a PSSCH is within a reference duration can be an indicator shown by the UE TX that the scheduled PSSCH is within a reference duration. The indicator can be transmitted via a one-bit indicator. The indicator can be carried by a 1st stage SCI, a 2nd stage SCI, or a CE MAC. The signaling carrying the indicator can be associated with the PSSCH.

[0096] As another example, information to determine whether a PSSCH is within a reference duration can be indicated by an initial PSSCH symbol within the PSSCH slot. Within the COT, only the first slot can be a partial slot, therefore the time pattern can be used to indicate the reference duration.

[0097] As a further example, information to determine whether a PSSCH is within a reference duration can be indicated by information associated with the PSSCH DMRS. Several time standards can be (pre-)configured for the PSSCH DMRS, and the 1st stage SCI can indicate which time standard is used for the associated PSSCH. The different time standards for the PSSCH DMRS may depend on the number of symbols for the PSSCH, the number of symbols with the PSSCH DMRS, and the number of symbols for the PSSCH within a slot.

[0098] In some other exemplary modalities, there may be other options that can determine the location (or definition) of the reference duration within a COT and information to determine the location of each PSSCH. The first option may comprise a complete COT duration and a remaining COT duration. For example, Rx UE may deduct a final slot from the COT. Petition 870250088252, dated 09 / 29 / 2025, page 42 / 91 34 / 62 based on the remaining COT duration and the slot carrying the remaining COT duration information. The Rx UE can deduce an initial slot for the COT according to the final slot and the total COT duration. The Rx UE can determine if a target PSSCH is located within the reference duration.

[0099] The second option may include the CAPC value used to initiate the COT (indicating the full COT duration) and the remaining COT duration. The other steps are similar to the first option.

[00100] In some implementations, if an Rx UE of a PSSCH wishes to transmit HARQ feedback to the PSSCH, the PSSCH's Rx UE can determine whether the PSSCH is located within the reference duration based on the information discussed above. In some exemplary embodiments, if it is determined that the PSSCH is located within the reference duration of a COT, the Rx UE can prioritize the transmission of the PSSCH carrying HARQ-ACK feedback corresponding to the PSSCH (e.g., setting the lowest priority value to the PSSCH to obtain the highest priority level).

[00101] Additionally or alternatively, if the UE Rx has multiple transmissions to perform simultaneously, the HARQ-ACK feedback transmission may be the last to be interrupted due to transmission limitation. In some example embodiments, if the UE Rx has transmission and reception to perform simultaneously, the HARQ-ACK feedback transmission may be the last to be interrupted due to transmission limitation. In some example embodiments, if multiple PSFCH occasions are provided to the PSSCH, the UE Rx may need to ensure at least one PSFCH transmission. In some example embodiments, if the above situations are not met, the UE Rx may treat the HARQ-ACK feedback to the remaining PSSCH as normal operation.

[00102] In some circumstances, if the PSSCH EU Tx does not Petition 870250088252, dated 09 / 29 / 2025, p. 43 / 91 35 / 62 receiving feedback on PSFCH occasions associated with PSSCH within the reference duration, the UE transmitter can perform CW size adjustment to increase the CW size to a larger value at each CAPC. This can occur because, with the above principle, the PSFCH transmission on which the CW size adjustment is based can receive the highest priority level. If a UE transmitter from the PSSCH does not receive HARQ feedback, it may be aware that the UE receiver is unable to transmit the PSFCH due to an LBT failure, in addition to the transmission drop. Thus, the UE transmitter can adjust the CW size to be less aggressive in using a highly loaded channel.

[00103] By implementing the modalities of this disclosure, an adjustment of a contention window size based on HARQ feedback in the unlicensed side link (SL-U) band can be supported, and a PSFCH transmission for which the adjustment of the contention window size can be guaranteed.

[00104] Figure 6 illustrates an example of a device 600 that supports the solution of a PSFCH transmission according to aspects of this disclosure. The device 600 may be an example of a UE 104-1, as described in this document. The device 600 may support wireless communication with one or more network entities 102, UEs 104, or any combination thereof. The device 600 may include components for bidirectional communications, including components for transmitting and receiving communications, such as a processor 602, a memory 604, a transceiver 606, and optionally an I / O controller 608. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[00105] The processor 602, the memory 604, the transceiver 606 Petition 870250088252, dated 09 / 29 / 2025, p. 44 / 91 36 / 62 or various combinations thereof or various components thereof may be examples of means for carrying out various aspects of the present disclosure, as described in this document. For example, processor 602, memory 604, transceiver 606, or various combinations or components thereof may support a method for carrying out one or more of the operations described in this document.

[00106] In some implementations, the 602 processor, the 604 memory, the 606 transceiver, or various combinations or components thereof may be implemented in hardware (for example, in communications management circuits). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means to perform the functions described in this disclosure. In some implementations, the 602 processor and the 604 memory coupled to the 602 processor may be configured to perform one or more of the functions described in this document (for example, executing instructions stored in the 604 memory by the 602 processor).

[00107] For example, processor 602 can support wireless communication on device 600, according to the examples disclosed in this document. Processor 602 can be configured to support means of receiving, a second UE, a PSSCH transmission; and means of determining whether the PSSCH transmission is within a reference duration of a COT, wherein a HARQ feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.

[00108] The 602 processor may include an intelligent hardware device (for example, a general-purpose processor, Petition 870250088252, dated 09 / 29 / 2025, page 45 / 91 37 / 62 a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the 602 processor may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the 602 processor. The 602 processor may be configured to execute computer-readable instructions stored in a memory (e.g., memory 604) to enable the 600 device to perform various functions of the present disclosure.

[00109] Memory 604 may include random access memory (RAM) and read-only memory (ROM). Memory 604 may store computer-readable, computer-executable code, including instructions that, when executed by processor 602, cause device 600 to perform various functions described in this document. The code may be stored in a non-transient, computer-readable medium, such as system memory or another type of memory. In some implementations, the code may not be directly executable by processor 602, but may cause a computer (e.g., when compiled and executed) to perform the functions described in this document. In some implementations, memory 604 may include, among other things, a basic I / O system (BIOS) that may control basic hardware or software operation, such as interaction with peripheral components or devices.

[00110] The 608 I / O controller can manage input and output signals for the 600 device. The 608 I / O controller can also manage peripherals not integrated into the M02 device. In some implementations, the 608 I / O controller may represent a physical connection or port for an external peripheral. In some implementations, the 608 I / O controller may utilize an operating system such as iOS®, ANDROID®, MS Petition 870250088252, dated 09 / 29 / 2025, pp. 46 / 91 38 / 62 WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the 608 I / O controller may be implemented as part of a processor, such as the 606 processor. In some implementations, a user may interact with the 600 device through the 608 I / O controller or through hardware components controlled by the 608 I / O controller.

[00111] In some implementations, the 600 device may include a single 610 antenna. However, in some other implementations, the 600 device may have more than one 610 antenna (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The 606 transceiver may communicate bidirectionally, via one or more 610 antennas, wired or wireless links, as described in this document. For example, the 606 transceiver may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The 606 transceiver may also include a modem to modulate the packets, provide the modulated packets to one or more 610 antennas for transmission, and demodulate packets received from one or more 610 antennas. The 606 transceiver may include one or more transmit chains, one or more receive chains, or a combination thereof.

[00112] A transmission chain can be configured to generate and transmit signals (e.g., control information, data, packets). The transmission chain may include at least one modulator to modulate data into a carrier signal, preparing the signal for wireless transmission. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes, such as phase-shift keying (PSK) or modulation of Petition 870250088252, dated 09 / 29 / 2025, page 47 / 91 39 / 62 amplitude in quadrature (QAM). The transmission chain may also include at least one power amplifier configured to amplify the modulated signal to a power level appropriate for wireless transmission. The transmission chain may also include one or more 610 antennas to transmit the amplified signal into the air or wirelessly.

[00113] A receiving chain can be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, the receiving chain might include one or more 610 antennas to receive the signal over the air or wirelessly. The receiving chain might include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiving chain might include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by inverting the modulation technique applied during signal transmission. The receiving chain might include at least one decoder to decode and process the demodulated signal to receive the transmitted data.

[00114] Figure 7 illustrates an example of a 700 device supporting a PSFCH transmission solution according to aspects of this disclosure. The 700 device may be an example of a UE 104-2, as described in this document. The 700 device may support wireless communication with one or more network entities 102, UEs 104, or any combination thereof. The 700 device may include components for bidirectional communications, including components for transmitting and receiving communications, such as a processor 702, a memory 704, a transceiver 706, and optionally an I / O controller 708. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., Petition 870250088252, dated 09 / 29 / 2025, pp. 48 / 91 40 / 62 busbars).

[00115] The 702 processor, the 704 memory, the 706 transceiver, or various combinations thereof, or various components thereof, may be examples of means for carrying out various aspects of the present disclosure, as described in this document. For example, the 702 processor, the 704 memory, the 706 transceiver, or various combinations or components thereof may support a method for carrying out one or more of the operations described in this document.

[00116] In some implementations, the 702 processor, the 704 memory, the 706 transceiver, or various combinations or components thereof may be implemented in hardware (for example, in communications management circuits). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means to perform the functions described in this disclosure. In some implementations, the 702 processor and the 704 memory coupled to the 702 processor may be configured to perform one or more of the functions described in this document (for example, executing, by the 702 processor, instructions stored in the 704 memory).

[00117] For example, processor 702 can support wireless communication on device 700, according to the examples disclosed in this document. Processor 702 can be configured to support means for transmitting a PSSCH transmission to one or more first UEs; and means for determining a contention window size in response to a failure to receive HARQ feedback from one or more first UEs. Petition 870250088252, dated 09 / 29 / 2025, page 49 / 91 41 / 62

[00118] The 702 processor may include an intelligent hardware device (for example, a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the 702 processor may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the 702 processor. The 702 processor may be configured to execute computer-readable instructions stored in a memory (for example, memory 704) to enable the 700 device to perform various functions of the present disclosure.

[00119] Memory 704 may include random access memory (RAM) and read-only memory (ROM). Memory 704 may store computer-readable, computer-executable code, including instructions that, when executed by processor 702, cause device 700 to perform various functions described in this document. The code may be stored in a non-transient, computer-readable medium, such as system memory or another type of memory. In some implementations, the code may not be directly executable by processor 702, but may cause a computer (e.g., when compiled and executed) to perform the functions described in this document. In some implementations, memory 704 may include, among other things, a basic I / O system (BIOS) that may control basic hardware or software operation, such as interaction with peripheral components or devices.

[00120] The 708 I / O controller can manage input and output signals for the 700 device. The 708 I / O controller can also manage peripherals not integrated into the M02 device. In some implementations, the 708 I / O controller may represent a physical connection or port for a peripheral. Petition 870250088252, dated 09 / 29 / 2025, pp. 50 / 91 42 / 62 external. In some implementations, the 708 I / O controller may utilize an operating system such as iOS®, ANDROID®, MSWINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the 708 I / O controller may be implemented as part of a processor, such as the 706 processor. In some implementations, a user may interact with the 700 device through the 708 I / O controller or through hardware components controlled by the 708 I / O controller.

[00121] In some implementations, the 700 device may include a single 710 antenna. However, in some other implementations, the 700 device may have more than one 710 antenna (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The 706 transceiver may communicate bidirectionally, via one or more 710 antennas, wired or wireless links, as described in this document. For example, the 706 transceiver may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The 706 transceiver may also include a modem to modulate the packets, to provide the modulated packets to one or more 710 antennas for transmission, and to demodulate packets received from one or more 710 antennas.The 706 transceiver may include one or more transmit chains, one or more receive chains, or a combination thereof.

[00122] A transmission chain can be configured to generate and transmit signals (e.g., control information, data, packets). The transmission chain may include at least one modulator to modulate data into a carrier signal, preparing the signal for wireless transmission. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM) schemes, Petition 870250088252, dated 09 / 29 / 2025, pp. 51 / 91 43 / 62 frequency modulation (FM) or digital modulation, such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmission chain may also include at least one power amplifier configured to amplify the modulated signal to a power level appropriate for wireless transmission. The transmission chain may also include one or more 710 antennas to transmit the amplified signal into the air or wirelessly.

[00123] A receiving chain can be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, the receiving chain might include one or more 710 antennas to receive the signal over the air or wirelessly. The receiving chain might include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiving chain might include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by inverting the modulation technique applied during signal transmission. The receiving chain might include at least one decoder to decode and process the demodulated signal to receive the transmitted data.

[00124] Figure 8 illustrates an example of an 800 device that supports the solution of a PSFCH transmission according to aspects of this disclosure. The 800 device may be an example of a 102 network entity, as described in this document. The 800 device may support wireless communication with one or more 102 network entities, 104 UEs, or any combination thereof. The 800 device may include components for bidirectional communications, including components for transmitting and receiving communications, such as an 802 processor, an 804 memory, an 806 transceiver, and optionally an 808 I / O controller. These components may be in electronic communication or coupled in another way (e.g., Petition 870250088252, dated 09 / 29 / 2025, pp. 52 / 91 44 / 62 operationally, communicatively, functionally, electronically, electrically) by means of one or more interfaces (e.g., buses).

[00125] The 802 processor, the 804 memory, the 806 transceiver, or various combinations thereof, or various components thereof, may be examples of means for carrying out various aspects of the present disclosure as described in this document. For example, the 802 processor, the 804 memory, the 806 transceiver, or various combinations or components thereof may support a method for carrying out one or more of the operations described in this document.

[00126] In some implementations, the 802 processor, the 804 memory, the 806 transceiver, or various combinations or components thereof may be implemented in hardware (for example, in communications management circuits). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means to perform the functions described in this disclosure. In some implementations, the 802 processor and the 804 memory coupled to the 802 processor may be configured to perform one or more of the functions described in this document (for example, executing, by the 802 processor, instructions stored in the 804 memory).

[00127] For example, the 802 processor can support wireless communication on the 800 device, according to the examples disclosed in this document. The 802 processor can be configured to support transmission media, for a UE, from a reference duration location to a COT, where a HARQ feedback associated with a PSSCH transmission Petition 870250088252, dated 09 / 29 / 2025, pp. 53 / 91 45 / 62 within the reference duration is used to determine the size of a containment window.

[00128] The 802 processor may include an intelligent hardware device (for example, a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the 802 processor may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the 802 processor. The 802 processor may be configured to execute computer-readable instructions stored in a memory (for example, the 804 memory) to enable the 800 device to perform various functions of the present disclosure.

[00129] 804 memory may include random access memory (RAM) and read-only memory (ROM). 804 memory may store computer-readable, computer-executable code, including instructions that, when executed by the 802 processor, cause the 800 device to perform various functions described in this document. The code may be stored in a non-transient, computer-readable medium, such as system memory or another type of memory. In some implementations, the code may not be directly executable by the 802 processor, but may cause a computer (e.g., when compiled and executed) to perform the functions described in this document. In some implementations, 804 memory may include, among other things, a basic I / O system (BIOS) that may control basic hardware or software operation, such as interaction with peripheral components or devices.

[00130] The 808 I / O controller can manage input and output signals for the 800 device. The 808 I / O controller can also manage peripherals not integrated into the device. Petition 870250088252, dated 09 / 29 / 2025, pp. 54 / 91 46 / 62 M02. In some implementations, the 808 I / O controller may represent a physical connection or port for an external peripheral. In some implementations, the 808 I / O controller may utilize an operating system such as iOS®, ANDROID®, MSWINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the 808 I / O controller may be implemented as part of a processor, such as the 806 processor. In some implementations, a user may interact with the 800 device through the 808 I / O controller or through hardware components controlled by the 808 I / O controller.

[00131] In some implementations, the 800 device may include a single 810 antenna. However, in some other implementations, the 800 device may have more than one 810 antenna (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The 806 transceiver may communicate bidirectionally, via one or more 810 antennas, wired or wireless links, as described in this document. For example, the 806 transceiver may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The 806 transceiver may also include a modem to modulate packets, provide modulated packets to one or more 810 antennas for transmission, and demodulate packets received from one or more 810 antennas. The 806 transceiver may include one or more transmit chains, one or more receive chains, or a combination thereof.

[00132] A transmission chain can be configured to generate and transmit signals (e.g., control information, data, packets). The transmission chain may include at least one modulator to modulate data into a carrier signal, preparing the signal for wireless transmission. The hair Petition 870250088252, dated 09 / 29 / 2025, pp. 55 / 91 47 / 62 minus one modulator can be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes, such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmission chain may also include at least one power amplifier configured to amplify the modulated signal to a power level appropriate for wireless transmission. The transmission chain may also include one or more 810 antennas to transmit the amplified signal into the air or wirelessly.

[00133] A receiving chain can be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, the receiving chain might include one or more 810 antennas to receive the signal over the air or wirelessly. The receiving chain might include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiving chain might include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by inverting the modulation technique applied during signal transmission. The receiving chain might include at least one decoder to decode and process the demodulated signal to receive the transmitted data.

[00134] Figure 9 illustrates an example of a 900 processor that supports a PSFCH transmission according to aspects of this disclosure. The 900 processor may be an example of a processor configured to perform various operations according to the examples described in this document. The 900 processor may include a 902 controller configured to perform various operations according to the examples described in this document. The 900 processor may optionally include at least one 904 memory, as an L1 / L2 / L3 cache. Additionally, or alternatively, the 900 processor may optionally include Petition 870250088252, dated 09 / 29 / 2025, pp. 56 / 91 48 / 62 one or more arithmetic logic units (ALUs) 906. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) by means of one or more interfaces (e.g., buses).

[00135] The 900 processor may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receive, get, retrieve, transmit, send, forward, store, determine, identify, access, write, read) as described in this document. The processor chipset may include one or more cores, one or more caches (e.g., local memory or memory included in the processor chipset (e.g., the 900 processor) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), and others).

[00136] Controller 902 can be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of processor 900 to enable processor 900 to support various base station operations, as described in the examples in this document. For example, controller 902 can operate as a control unit for processor 900, generating control signals that manage the operation of various components of processor 900. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating the timing of operations. Petition 870250088252, dated 09 / 29 / 2025, pp. 57 / 91 49 / 62

[00137] Controller 902 can be configured to fetch (e.g., get, retrieve, receive) instructions from memory 904 and determine the subsequent instruction(s) to be executed to enable processor 900 to support various operations as described in this document. Controller 902 can be configured to track the memory address of instructions associated with memory 904. Controller 902 can be configured to decode instructions to determine the operation to be performed and the operands involved. For example, controller 902 can be configured to interpret the instruction and determine the control signals to be sent to other components of processor 900 to enable processor 900 to support various operations as described in this document. Additionally, or alternatively, controller 902 can be configured to manage the data flow within processor 900.The 902 controller can be configured to control data transfer between registers, arithmetic logic units (ALUs), and other functional units of the 900 processor.

[00138] The 904 memory may include one or more caches (e.g., local memory or memory included in the 900 processor or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc.). In some implementations, the 904 memory may reside within or on a processor chipset (e.g., local to the 900 processor). In some other implementations, the 904 memory may reside externally to the processor chipset (e.g., remote to the 900 processor).

[00139] Memory 904 can store computer-readable, computer-executable code, including instructions that, when executed by processor 900, cause processor 900 to perform various functions described in this document. The code can be stored on a non-computer-readable medium. Petition 870250088252, dated 09 / 29 / 2025, pp. 58 / 91 50 / 62 transient, such as system memory or other types of memory. Controller 902 and / or processor 900 can be configured to execute computer-readable instructions stored in memory 904 to enable processor 900 to perform various functions. For example, processor 900 and / or controller 902 can be coupled to memory 904, and processor 900, controller 902, and memory 904 can be configured to perform various functions described in this document. In some examples, processor 900 may include multiple processors, and memory 904 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions described in this document.

[00140] One or more 906 ALUs can be configured to support various operations as described in this document. In some implementations, one or more 906 ALUs may reside within or on a processor chipset (e.g., the 900 processor). In some other implementations, one or more 906 ALUs may reside externally to the processor chipset (e.g., the 900 processor). One or more 906 ALUs can perform one or more calculations, such as addition, subtraction, multiplication, and division, on data. For example, one or more 906 ALUs may receive input operands and an operation code, which determines an operation to be performed. One or more 906 ALUs can be configured with a variety of logic and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation.Additionally, or alternatively, one or more 906 ALUs can support logical operations such as AND, OR, XOR, NOR, and NAND, allowing one or more 906 ALUs to handle conditional operations, comparisons, and bitwise operations. Petition 870250088252, dated 09 / 29 / 2025, pp. 59 / 91 51 / 62

[00141] The 900 processor can support wireless communication according to the examples disclosed in this document. The 900 processor can be configured or operated to support means for receiving, from a second UE, a PSSCH transmission; and means for determining whether the PSSCH transmission is within a reference duration of a COT, wherein a HARQ feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.

[00142] Figure 10 illustrates an example of a processor 1000 that supports a PSFCH transmission according to aspects of this disclosure. The processor 1000 may be an example of a processor configured to perform various operations according to the examples described in this document. The processor 1000 may include a controller 1002 configured to perform various operations according to the examples described in this document. The processor 1000 may optionally include at least one memory 1004, as an L1 / L2 / L3 cache. Additionally, or alternatively, the processor 1000 may optionally include one or more arithmetic logic units (ALUs) 1006. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) through one or more interfaces (e.g., buses).

[00143] The 1000 processor may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receive, get, retrieve, transmit, send, forward, store, determine, identify, access, write, read) as described in this document. The processor chipset may include one or more cores, one or more caches (e.g., local memory). Petition 870250088252, dated 09 / 29 / 2025, pp. 60 / 91 52 / 62 or included in the processor chipset (e.g., the 1000 processor) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), and others).

[00144] Controller 1002 can be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of processor 1000 to enable processor 1000 to support various UE operations, as described in the examples in this document. For example, controller 1002 can operate as a control unit for processor 1000, generating control signals that manage the operation of various components of processor 1000. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating the timing of operations.

[00145] Controller 1002 can be configured to fetch (e.g., get, retrieve, receive) instructions from memory 1004 and determine the subsequent instruction(s) to be executed to enable processor 1000 to support various operations as described in this document. Controller 1002 can be configured to track the memory address of instructions associated with memory 1004. Controller 1002 can be configured to decode instructions to determine the operation to be performed and the operands involved. For example, controller 1002 can be configured to interpret the instruction and determine the control signals to be sent to other components of processor 1000 to enable processor 1000 to support various operations as described in this document. Petition 870250088252, dated 09 / 29 / 2025, pp. 61 / 91 53 / 62 Additionally, or alternatively, controller 1002 can be configured to manage the data flow within processor 1000. Controller 1002 can be configured to control data transfer between registers, arithmetic logic units (ALUs), and other functional units of processor 1000.

[00146] Memory 1004 may include one or more caches (e.g., local memory or memory included in processor 1000 or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc.). In some implementations, memory 1004 may reside within or on a processor chipset (e.g., local to processor 1000). In some other implementations, memory 1004 may reside externally to the processor chipset (e.g., remote to processor 1000).

[00147] Memory 1004 can store computer-readable, computer-executable code, including instructions that, when executed by processor 1000, cause processor 1000 to perform various functions described in this document. The code can be stored in a non-transient, computer-readable medium, such as system memory or another type of memory. Controller 1002 and / or processor 1000 can be configured to execute computer-readable instructions stored in memory 1004 to cause processor 1000 to perform various functions. For example, processor 1000 and / or controller 1002 can be coupled to memory 1004, and processor 1000, controller 1002, and memory 1004 can be configured to perform various functions described in this document. In some examples, processor 1000 can include multiple processors and memory 1004 can include multiple memories.One or more of the multiple processors can be coupled to one or more of the multiple memories, which can be configured, individually or collectively, to perform various functions described in this document. Petition 870250088252, dated 09 / 29 / 2025, pp. 62 / 91 54 / 62

[00148] One or more 1006 ALUs can be configured to support various operations as described in this document. In some implementations, one or more 1006 ALUs may reside within or on a processor chipset (e.g., the 1000 processor). In some other implementations, one or more 1006 ALUs may reside externally to the processor chipset (e.g., the 1000 processor). One or more 1006 ALUs can perform one or more calculations, such as addition, subtraction, multiplication, and division, on data. For example, one or more 1006 ALUs may receive input operands and an operation code, which determines an operation to be performed. One or more 1006 ALUs can be configured with a variety of logic and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation.Additionally, or alternatively, one or more 1000 ALUs can support logical operations such as AND, OR, XOR, NOR, and NAND, allowing one or more 1006 ALUs to handle conditional operations, comparisons, and bitwise operations.

[00149] The 1000 processor can support wireless communication according to the examples disclosed in this document. The 1000 processor can be configured or operated to support means for transmitting, to one or more first UEs, a PSSCH transmission; and means for determining a contention window size in response to a failure to receive a HARQ feedback from one or more first UEs.

[00150] Figure 11 illustrates an example of an 1100 processor that supports a PSFCH transmission according to aspects of this disclosure. The 1100 processor may be an example of a processor configured to perform various operations according to the examples described in this document. The 1100 processor may include an 1102 controller configured to perform various operations according to the examples described in this document. Petition 870250088252, dated 09 / 29 / 2025, pp. 63 / 91 55 / 62 document. The 1100 processor may optionally include at least one 1104 memory, such as L1 / L2 / L3 cache. Additionally, or alternatively, the 1100 processor may optionally include one or more arithmetic logic units (ALUs) 1106. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) by means of one or more interfaces (e.g., buses).

[00151] The 1100 processor may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receive, get, retrieve, transmit, send, forward, store, determine, identify, access, write, read) as described in this document. The processor chipset may include one or more cores, one or more caches (e.g., local memory or memory included in the processor chipset (e.g., the 1100 processor) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), and others).

[00152] The 1102 controller can be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the 1100 processor to enable the 1100 processor to support various UE operations, as described in the examples in this document. For example, the 1102 controller can operate as a control unit for the 1100 processor, generating control signals that manage the operation of various components of the 1100 processor. Petition 870250088252, dated 09 / 29 / 2025, pp. 64 / 91 56 / 62 These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating the timing of operations.

[00153] Controller 1102 can be configured to fetch (e.g., get, retrieve, receive) instructions from memory 1104 and determine the subsequent instruction(s) to be executed to enable processor 1100 to support various operations as described in this document. Controller 1102 can be configured to track the memory address of instructions associated with memory 1104. Controller 1102 can be configured to decode instructions to determine the operation to be performed and the operands involved. For example, controller 1102 can be configured to interpret the instruction and determine the control signals to be sent to other components of processor 1100 to enable processor 1100 to support various operations as described in this document. Additionally, or alternatively, controller 1102 can be configured to manage the data flow within processor 1100.The 1102 controller can be configured to control data transfer between registers, arithmetic logic units (ALUs), and other functional units of the 1100 processor.

[00154] 1104 memory may include one or more caches (e.g., local memory or memory included in the 1100 processor or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc.). In some implementations, 1104 memory may reside within or on a processor chipset (e.g., local to the 1100 processor). In some other implementations, 1104 memory may reside externally to the processor chipset (e.g., remote to the 1100 processor).

[00155] Memory 1104 can store computer-readable, computer-executable code, including instructions that, Petition 870250088252, dated 09 / 29 / 2025, pp. 65 / 91 Instructions 57 / 62, when executed by processor 1100, cause processor 1100 to perform various functions described in this document. The code can be stored in a non-transient, computer-readable medium, such as system memory or other types of memory. Controller 1102 and / or processor 1100 can be configured to execute computer-readable instructions stored in memory 1104 to cause processor 1100 to perform various functions. For example, processor 1100 and / or controller 1102 can be coupled to memory 1104, and processor 1100, controller 1102, and memory 1104 can be configured to perform various functions described in this document. In some examples, processor 1100 may include multiple processors, and memory 1104 may include multiple memories.One or more of the multiple processors can be coupled to one or more of the multiple memories, which can be configured, individually or collectively, to perform various functions described in this document.

[00156] One or more 1106 ALUs can be configured to support various operations as described in this document. In some implementations, one or more 1106 ALUs may reside within or on a processor chipset (e.g., the 1100 processor). In some other implementations, one or more 1106 ALUs may reside externally to the processor chipset (e.g., the 1100 processor). One or more 1106 ALUs can perform one or more calculations, such as addition, subtraction, multiplication, and division, on data. For example, one or more 1106 ALUs may receive input operands and an operation code, which determines an operation to be performed. One or more 1106 ALUs can be configured with a variety of logic and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, one or more 1100 ALUs may support Petition 870250088252, dated 09 / 29 / 2025, pp. 66 / 91 58 / 62 logical operations such as AND, OR, XOR, NOR, and NAND, allowing one or more 1106 ALUs to handle conditional operations, comparisons, and bitwise operations.

[00157] The 1100 processor can support wireless communication according to the examples disclosed in this document. The 1100 processor can be configured or operated to support transmission media, for a UE, from a location with a reference duration to a COT, where a HARQ feedback associated with a PSSCH transmission within the reference duration is used to determine a contention window size.

[00158] Figure 12 illustrates a flowchart of a 1200 method that supports a PSFCH transmission in accordance with aspects of this disclosure. The operations of the 1200 method can be implemented by a device or its components, as described in this document. For example, the operations of the 1200 method can be performed by a UE 104-1, as described in this document. In some implementations, the device may execute a set of instructions to control the device's function elements to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[00159] In 1205, the method may include receiving a PSSCH transmission from a second UE. 1205 operations can be performed according to the examples described in this document. In some implementations, aspects of 1205 operations may be performed by a device as described with reference to Figure 1.

[00160] In 1210, the method may include determining whether PSSCH transmission is within a COT reference duration, where HARQ feedback associated with PSSCH transmission within the reference duration is used to determine the size of a containment window. 1210 operations may Petition 870250088252, dated 09 / 29 / 2025, pp. 67 / 91 59 / 62 to be performed according to the examples described in this document. In some implementations, aspects of the 1210 operations may be performed by a device as described with reference to Figure 1.

[00161] Figure 13 illustrates a flowchart of a 1300 method that supports a PSFCH transmission in accordance with aspects of this disclosure. The operations of the 1300 method can be implemented by a device or its components, as described in this document. For example, the operations of the 1300 method can be performed by a UE 104-2, as described in this document. In some implementations, the device may execute a set of instructions to control the device's function elements to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[00162] In 1305, the method may include transmitting, to one or more first UEs, a PSSCH transmission. 1305 operations may be performed according to the examples described in this document. In some implementations, aspects of 1305 operations may be performed by a device as described with reference to Figure 1.

[00163] In 1310, the method may include determining the size of a contention window in response to a failure to receive HARQ feedback from one or more first UEs. 1310 operations can be performed according to the examples described in this document. In some implementations, aspects of 1310 operations may be performed by a device as described with reference to Figure 1.

[00164] Figure 14 illustrates a flowchart of a 1400 method that supports PSFCH transmission in accordance with aspects of this disclosure. The operations of the 1400 method can be implemented by a device or its components, as described in this document. For example, the operations of the method Petition 870250088252, dated 09 / 29 / 2025, pp. 68 / 91 60 / 62 1400 can be performed by a network entity 102, as described in this document. In some implementations, the device may execute a set of instructions to control its function elements to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[00165] In 1405, the method may include transmitting, to a UE, a location with a reference duration for a COT, where a HARQ feedback associated with a PSSCH transmission within the reference duration is used to determine a contention window size. 1405 operations can be performed according to the examples described in this document. In some implementations, aspects of 1405 operations may be performed by a device as described with reference to Figure 1.

[00166] It should be noted that the methods described in this document describe possible implementations, and that operations and steps may be rearranged or modified in other ways, and that other implementations are possible. Furthermore, aspects of two or more methods may be combined.

[00167] The various illustrative blocks and components described in connection with this disclosure may be implemented or realized with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described in this document. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a Petition 870250088252, dated 09 / 29 / 2025, pp. 69 / 91 61 / 62 A DSP and a microprocessor, multiple microprocessors, one or more microprocessors together with a DSP core, or any other such configuration.

[00168] The functions described in this document may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored or transmitted as one or more instructions or code in a computer-readable medium. Other examples and implementations are within the scope of the disclosure and the appended claims. For example, due to the nature of software, the functions described in this document may be implemented using software executed by a processor, hardware, firmware, cabling, or combinations thereof. Resources implementing functions may also be physically located in multiple locations, including being distributed such that parts of the functions are implemented in different physical locations.

[00169] Computer-readable media include non-transient storage media and communication media, including any means that facilitate the transfer of a computer program from one place to another. A non-transient storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer. By way of example, non-transient computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, magnetic disc storage or other magnetic storage devices, or any other non-transient medium that can be used to carry or store desired program code media in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer. Petition 870250088252, dated 09 / 29 / 2025, pp. 70 / 91 62 / 62 special, or a general-purpose or special-purpose processor.

[00170] As used in this document, including in the claims, the article "a" before an element is unrestricted and understood as referring to at least one of those elements or to one or more of those elements. The terms "a," "at least one," "one or more," and "at least one of one or more" may be interchangeable. As used in this document, including in the claims, or as used in a list of items (for example, a list of items preceded by a phrase such as "at least one of" or "one or more of" or "one or both of") indicates an inclusive list, so that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used in this document, the phrase "based on" should not be interpreted as referring to a closed set of conditions.For example, an example step described as being based on condition A may be based on either condition A or condition B, without departing from the scope of this disclosure. In other words, as used in this document, the expression “based on” should be interpreted in the same way as the expression “based at least in part on”. Furthermore, as used in this document, including in the claims, a “set” may include one or more elements.

[00171] The description in this document is provided to enable a person of ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person of ordinary skill in the art, and the generic principles set forth in this document may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described in this document, but should be given the broader scope consistent with the principles and new features disclosed in this document. Petition 870250088252, dated 09 / 29 / 2025, pp. 71-91

Claims

1 / 6 CLAIMS 1. First user equipment (UE) characterized in that it comprises: a processor; and a transceiver coupled to the processor, wherein the processor is configured to: receive, through the transceiver and a second UE, a physical side link shared channel transmission (PSSCH); and determine whether the PSSCH transmission is within a reference duration of a channel occupation time (COT), wherein a hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission within the reference duration is used to determine a contention window size.

2. First UE, according to claim 1, characterized in that the determination of whether the PSSCH transmission is within the reference duration is based on one of the following: an indicator showing whether the PSSCH transmitted by the second UE is within the reference duration; an initial symbol of the PSSCH transmission within a PSSCH slot; or a time pattern configured for a PSSCH demodulation reference signal (DMRS) associated with the PSSCH transmission.

3. First UE, according to claim 2, characterized in that the indicator is transmitted by means of one of the following: a first-stage side link control information (SCI); a second-stage SCI; or a medium access control (MAC) element. Petition 870250088252, dated 29 / 09 / 2025, pp. 72 / 91 2 / 6 4. First EU, according to claim 1, characterized in that a reference duration location is one of the following: a first slot for PSSCH transmission within the COT, wherein the first slot starts from a first candidate initial position within the COT slot; a first slot for PSSCH transmission within the COT, wherein the first slot starts from a first candidate initial position or a second candidate initial position within the COT slot; or a first slot and a second slot adjacent to the first slot for PSSCH transmission, wherein the first slot starts from a second candidate initial position within the COT slot.

5. First EU, according to claim 4, characterized in that the determination of whether PSSCH transmission is within the reference duration is based on the location of the reference duration within the COT and the location of PSSCH transmission.

6. First EU, according to claim 5, characterized in that the determination of the PSSCH transmission location is based on one of the following: a Channel Access Priority Class (CAPC) value used to initiate the COT and a remaining COT duration; or a complete COT duration and a remaining COT duration.

7. First EU, according to claim 5, characterized in that the determination of the location of the PSSCH transmission comprises: determining a final COT slot based on the remaining COT duration and a slot containing information on the remaining duration; determining a starting COT slot based on the final slot and the total COT duration; and determining the location of the PSSCH transmission based on the starting slot. Petition 870250088252, dated 29 / 09 / 2025, pp. 73 / 91 3 / 6 8. First UE, according to claim 5, characterized in that the location of the reference duration is configured by means of one of the following: a radio resource control signal (RRC); a system information block (SIB); a master information block (MIB); or a MAC CE.

9. First UE, according to any one of claims 1-8, characterized in that the processor is further configured to: determine a physical side link feedback channel (PSFCH) transmission carrying a HARQ acknowledgment (ACK) feedback associated with the PSSCH transmission to be of a higher priority level; and transmit, through the transceiver and to the second UE, the PSFCH transmission with the higher priority level.

10. First UE, according to claim 9, characterized in that: in the case of the first UE performing multiple transmissions, the PSFCH transmission is the last to be discarded due to a transmission limitation; in the case of the first UE transmitting and receiving multiple transmissions, the PSFCH transmission is the last to be discarded due to a transmission limitation; and in the event of multiple PSFCH occasions, performing at least one PSFCH transmission.

11. Second user equipment (UE) characterized in that it comprises: a processor; and a transceiver coupled to the processor, wherein the processor is configured to: transmit, through the transceiver and to one or more first UEs, a shared channel transmission of Petition 870250088252, dated 09 / 29 / 2025, page 74 / 91 4 / 6 physical side link (PSSCH); and determine a contention window size in response to a failure to receive a hybrid automatic repeat request (HARQ) feedback from one or more first UEs.

12. Second UE, according to claim 11, characterized in that the processor is further configured to: transmit, via the transceiver and to one or more first UEs, an indicator showing whether the PSSCH transmission is within a reference duration.

13. According to the EU, as per claim 12, characterized in that the indicator is transmitted via one of the following: a first-stage side link control information (SCI); a second-stage SCI; or a medium access control (MAC) element.

14. Second UE, according to claim 11, characterized in that the second UE determines the size of the contention window in the case of a HARQ acknowledgment (ACK) feedback corresponding to the PSSCH transmission being enabled, wherein the HARQ ACK feedback indicates that a first UE must transmit an ACK if the first UE correctly decodes a side-link shared channel transport block (SL-SCH), and the first UE must transmit a negative acknowledgment (NACK) if the first UE has detected the SL-SCH TB, but the first UE fails to decode the SL-SCH TB.

15. Second UE, according to claim 14, characterized in that HARQ ACK feedback is enabled in response to one of the following conditions: Petition 870250088252, dated 29 / 09 / 2025, page 75 / 91 5 / 6 in the case of PSSCH transmission being for SL unicast, HARQ ACK feedback comprising ACK or NACK corresponding to the PSSCH transmission is not received from a target UE of one or more first UEs; in the case of PSSCH transmission being for SL groupcast, HARQ ACK feedback comprising ACK or NACK corresponding to the PSSCH transmission is not received from one or more target UEs of one or more first UEs; Or, in the case of PSSCH transmission being for SL groupcast, the ratio of the number of HARQ feedbacks received to the number of the first one or more UEs within the groupcast transmission is below a threshold ratio.

16. Second UE, according to claim 14 or 15, characterized in that the second UE fails to receive HARQ ACK feedback, and the processor is still configured to do one of the following: increase the contention window size for each channel access priority class (CAPC); keep the contention window size unchanged; or keep the contention window size unchanged until HARQ feedback is received on a subsequent transmission occasion of a physical side link feedback channel (PSFCH), and adjust the contention window size based on the HARQ ACK feedback carried out in the PSFCH transmission.

17. Second UE, according to claim 14 or 15, characterized in that a PSFCH transmission carrying a HARQ ACK feedback associated with the PSSCH transmission is determined to be of a higher priority level by at least one UE of the first one or more UEs, and the second UE fails to receive the HARQ feedback associated with multiple PSFCH instances towards the PSSCH transmission within a reference duration, and the processor is further configured to: Petition 870250088252, dated 29 / 09 / 2025, p. 76 / 91 6 / 6 increase the contention window size for each CPAC.

18. Base station (BS) characterized in that it comprises: a processor; and a transceiver coupled to the processor, wherein the processor is configured to: transmit, through the transceiver and to a user equipment (UE), a location of a reference duration for a channel occupation time (COT), wherein a hybrid automatic repeat request feedback (HARQ) associated with a physical side link shared channel transmission (PSSCH) within the reference duration is used to determine a contention window size.

19. BS, according to claim 18, characterized in that the PSSCH transmission is for side link (SL) groupcast, and the processor is configured to: transmit, through the transceiver and to the UE, a ratio of a number of HARQ feedbacks corresponding to the PSSCH transmission and a number of UEs within the SL groupcast.

20. A method implemented by a first user equipment (UE) characterized in that it comprises: receiving, from a second UE, a physical side link shared channel transmission (PSSCH); and determining whether the PSSCH transmission is within a reference duration of a channel occupation time (COT), wherein a hybrid automatic repeat request (HARQ) feedback associated with the PSSCH transmission within the reference duration is used to determine the size of a contention window. Petition 870250088252, dated 09 / 29 / 2025, pp. 77 / 91

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