Resource selection for sidelink communication (SL-U) on unlicensed bands

Abstract

Several aspects of this description relate to a Mode 2 resource selection technique for sidelink communications (SL-U) over unlicensed bands based on CCA operation. The transmitting UE performs a CCA operation and then selects a resource using a Mode 2 detection and resource selection procedure. The detection algorithm begins by identifying potential candidate resources within a selection window. In some aspects, the selection window is bounded by the expected CCA time for a Type 1 CCA operation, and thus potential candidate resources are limited to time slots after the expected completion time of the Type 1 CCA operation. This can improve the transmission success rate of SL-U transmissions by reducing the frequency of transmission failures due to incomplete CCA operations.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication network, including techniques for sidelink communication in an unlicensed band.

Background Art

[0002] With the increasing use of mobile applications, the development of wireless systems capable of delivering large amounts of data at high speed has been attracting great attention. Sidelink (SL) communication can be used to facilitate direct device-to-device communication and to reduce the load by bypassing the base station, enabling rapid data exchange in a short time. Solutions for efficiency and reliability continue to evolve to include improvements and new features.

Brief Description of the Drawings

[0003] The present disclosure will be readily understood and capable of being implemented by means of a detailed description and the figures in the accompanying drawings. Like reference numerals may indicate like features and structural elements. The figures and corresponding descriptions are provided as non-limiting examples of aspects, implementations, etc. of the present disclosure, and references to "an" or "one" aspect, implementation, etc. do not necessarily refer to the same aspect, implementation, etc., but may mean at least one, one or more, etc.

[0004] [Figure 1] It is a block diagram showing a plurality of user equipments (UEs) configured to perform sidelink communication (SL-U) in an unlicensed band according to some aspects of the present description.

[0005] [Figure 2] It is a schematic diagram showing the timing of resource selection for SL-U according to some aspects of the present description.

[0006] [Figure 3]Schematic diagram showing the timing for resource selection based on Clear Channel Assessment (CCA) for SL-U operation according to some aspects of this description.

[0007] [Figure 4] Logical flow diagram showing a process for selecting and excluding resources based on the CCA operation for SL-U according to some aspects of this description.

[0008] [Figure 5] Schematic diagram showing selecting and excluding resources based on the CCA operation for SL-U according to some aspects of this description.

[0009] [Figure 6] Process flow diagram showing a process for a transmitting UE to perform sidelink communication (SL-U) on an unlicensed band according to some aspects of this description.

[0010] [Figure 7] Logical flow diagram showing a process for a transmitting UE to receive shared channel occupancy time (COT) information and select resources for SL-U according to some aspects of this description.

[0011] [Figure 8] Schematic diagram showing the timing for resource selection for SL-U according to some aspects of this description.

[0012] [Figure 9] Process flow diagram showing a process of a transmitting UE to perform sidelink communication (SL-U) on an unlicensed band using a shared COT according to some aspects of this description.

[0013] [Figure 10] Block diagram showing a device that can be used to perform resource selection for SL-U using the CCA operation according to some aspects of this description.

[0014] [Figure 11] This block diagram shows a baseband circuit that may be used to perform resource selection for SL-U using CCA operation, according to some aspects of this description. [Modes for carrying out the invention]

[0015] The following detailed description refers to the attached drawings. Similar figured symbols in different drawings may identify the same or similar features, elements, functions, etc. In addition, other implementations may be used and structural or logical modifications may be made without departing from the scope of this disclosure, so this disclosure is not limited to the following description.

[0016] A wireless communication network may include user equipment (UEs) capable of wirelessly communicating with base stations and other network nodes, and may also include direct communication between UEs using sidelink signaling. For sidelink communication between UEs, resource allocation may be performed using either Mode 1 or Mode 2. In Mode 1, the network (e.g., a base station) allocates resources and communicates the resource allocation to the UEs via Uu operations, and the UEs use the allocated resources to transmit / receive sidelink signals. In Mode 2, a transmitting UE participating in sidelink communication can autonomously allocate resources and use the allocated resources to communicate data to one or more other UEs. Sidelink resources may be determined based on a detection and selection procedure, supported by resource reservation announcements from other UEs. Resources may be selected and / or reserved from a sidelink resource pool, which can be shared by multiple sidelink UEs.

[0017] In addition, sidelink transmission may use unlicensed frequency bands for standalone operation or license-assisted access as a complementary spectrum to provide higher system capacity and transmission flexibility. To operate in unlicensed frequency bands, a UE may perform one or more Clear Channel Assessment (CCA) operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting within the unlicensed spectrum. CCA operations may be performed using the Listen Before Talk (LBT) protocol or other channel occupancy detection procedures. For example, a transmitting UE may listen for other potential transmission activity on a channel for a deferral duration before declaring the channel available, and then wait for a backoff period before transmitting. CCA operations are useful for coordinating spectrum usage across multiple devices and even across different radio access technologies. However, the time required for CCA operations, such as the deferral duration and backoff period mentioned, may negatively impact the success of sidelink resource selection and thus delay the transmission of sidelink data. For example, a time slot for a resource selected by the sending UE may arrive before the CCA operation is complete, which would result in a failure to send sidelink data using the selected resource.

[0018] Therefore, several aspects of this description relate to a Mode 2 resource selection technique for sidelink communication (SL-U) over unlicensed bands based on CCA operation. The transmitting UE performs a CCA operation and then selects a resource using a Mode 2 detection and resource selection procedure. The detection algorithm begins by identifying potential candidate resources within the selection window. In some aspects, the selection window is bounded by the expected CCA time for a Type 1 CCA operation, and thus potential candidate resources are limited to time slots after the expected completion time of a Type 1 CCA operation. This can improve the transmission success rate of SL-U transmissions by reducing the occurrence of transmission failures due to incomplete CCA operations. As an addition or alternative, the selection window is bounded by the COT duration of a shared COT initiated by the initializing UE when selecting or re-selecting resources for transmission to the initializing UE using a shared COT. In some further aspects, the transmitting UE receives consistent LBT failure indications from higher layers and, accordingly, excludes corresponding resources to form a coordinated (e.g., remaining) set of candidate resources. Therefore, since busy channels are excluded without multiple separate CCA operations, the efficiency of resource selection and subsequent SL-U transmissions can be improved. Additional aspects and details of this disclosure are further described below with reference to the figures.

[0019] Figure 1 is a block diagram illustrating the system and devices of Network Example 100, including UE110-1, UE110-2, UE110-3, UE110-4, etc. (hereinafter also referred to as UE110), configured to perform sidelink communication over an unlicensed band, according to several aspects of this description, as well as related methods and operations. UE110 can also communicate with and establish connections with Radio Access Network (RAN) nodes such as base station 111 (e.g., they can be communicatively coupled). UE110-1 is shown as a transmitting UE having sidelink data to be transmitted to receiving UEs such as UE110-2. In resource allocation mode 2, transmitting UE110-1 autonomously determines the resources to use for sidelink transmission based on a detection and resource selection procedure 106, which will be described in more detail below and will also be associated with Figure 2. The detection and resource selection procedure 106 may be assisted by resource reservations 102 received from other UE110-2, 110-3, 110-4, etc. Resource reservation 102 may be broadcast by other UE110-2, UE110-3, and UE110-4 as part of a first stage SCI transmitted over the Physical Sidelink Control Channel (PSCCH). Resources may be reserved and / or selected from a sidelink resource pool that can be shared by multiple UE110s.

[0020] UE110s communicate with each other via licensed media (also known as “licensed spectrum” and / or “licensed bands”), unlicensed media (also known as “unlicensed spectrum” and / or “unlicensed bands”), and / or combinations thereof. Licensed spectrum may correspond to channels or frequency bands selected, reserved, or regulated for certain types of wireless activity (e.g., wireless far-field communication network activity), while unlicensed spectrum may correspond to one or more frequency bands that are not restricted for any particular type of wireless activity. Whether a particular frequency band corresponds to licensed media or unlicensed media may depend on one or more factors, such as frequency allocation determined by public sector organizations (e.g., government agencies, regulatory bodies, etc.) or frequency allocation determined by private sector organizations involved in the development of wireless communication standards and protocols.

[0021] To operate in the unlicensed spectrum, the UE 110 and base station 111 can operate standalone or using license-assisted access (LAA), eLAA, and / or feLAA mechanisms. In these implementations, the transmitting UE 110-1 may perform a CCA operation 104, such as various types of medium detection or carrier detection operations, to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting in the unlicensed spectrum. The medium / carrier detection operation may be performed according to the Listen Before Talk (LBT) protocol and other procedures.

[0022] As indicated by action 112, the transmitting UE 110-1 then transmits sidelink data to the receiving UE 110-2 via a selected resource. The sidelink data is transmitted as transport blocks (TBs) carried over the physical sidelink shared channel (PSSCH). The TBs are associated with an SCI. The SCI indicates the resources used by the PSSCH that carry the associated TB, and further information for decoding the TB. The SCI may be transmitted in the same slot as the sidelink data and is in two stages. The first stage SCI is carried over the physical sidelink control channel (PSCCH), and the second stage SCI is carried over the corresponding PSSCH that carries the TB. The second stage SCI allows for flexible SCI design to support unicast, groupcast, and broadcast transmissions. By dividing the SCI into two stages, other UEs (e.g., UEs 110-3, 110-4) can decode only the first stage of the SCI for channel detection purposes to determine the resources reserved for the transmitting UE 110-1. Meanwhile, the second stage of the SCI provides additional control information necessary for transmission to the receiving UE 110-2.

[0023] As shown by Action 114, in some embodiments, transmitting UE 110-1 may receive shared COT information initiated by another UE, such as UE 110-2, as the initializing UE of a shared COT potentially shared by UE 110-1 and / or other COT-sharing candidate UEs such as UE 110-3, 110-4. The shared COT information is transmitted from UE 110-2 to UE 110-1 along with a data payload. The shared COT information indicates parameters of the shared COT, such as the duration of the COT, the UE identifier of the initializing UE, and the Channel Access Priority Class (CAPC) value for allowing the COT (CAPC-COT). The shared COT information is transmitted on a first-stage SCI carried on a PSCCH and may be broadcast or groupcast to multiple UEs such as UE 110-1, 110-3, 110-4. The data payload may be transmitted on a PSSCH and sent to UE 110-1 in the same slot as the PSCCH carrying the shared COT information.

[0024] As shown by the first indicator 1.1 and further described in relation to Figure 2 and other figures herein, in some embodiments, the expected period for performing the CCA operation 104 is used to define the resource selection window for the detection and resource selection procedure 106. Specifically, the start time of the resource selection window is the minimum expected period ("T") for the CCA operation 104. CCA_min The end time of the resource selection window includes the maximum expected period for CCA operation 104 ("T"). CCA_max Includes ''). CCA_min and T CCA_max This is calculated based on the channel access priority class (CAPC) value of the transmitted sidelink data and the current competition window size ("CW_p") of the CCA operation 104. In some further embodiments, the CCA operation 104 includes determining the channel occupancy rate Roc, and T CCA_min and T CCA_max This is further calculated based on channel occupancy.

[0025] As indicated by the second indicator 1.2 and further described in relation to Figure 3 and other figures herein, in some embodiments, the channel occupancy status determined by the CCA operation 104 is used to exclude resources during the detection and resource selection procedure 106. Specifically, information on resource block sets with consistent LBT failures is obtained and shown from the MAC layer to the physical layer of the transmitting UE 110-1, and the resource block sets are used to select an initial set of candidate resources "S A It will be excluded from ".

[0026] As shown by the third indicator 1.3 and further described in relation to Figure 2 and other figures herein, in some embodiments, when the transmitting UE 110-1 shares a COT with the receiving UE 110-2, resource selection is performed based on the parameters of the COT. For example, the resource selection window (e.g., the selection window 202 in Figure 2) is bounded by the COT duration of the COT so that SL transmissions can be transmitted and completed in a timely manner during the COT.

[0027] Furthermore, the base station 111 may be configured to communicate wirelessly with the UE 110 and may provide the UE 110 with a Mode 2 sidelink resource allocation configuration, as indicated by action 116. These configurations are intended to optimize the use of available resources and ensure that the UE 110 can communicate with each other reliably and efficiently. For example, the base station 111 may configure the size and number of resource blocks available for use by the UE 110. This may include reserving certain resource blocks for specific use cases, such as emergency services or certain types of communications. The base station 111 can also configure the sidelink channel, including selecting the frequency band, bandwidth, and modulation scheme used for sidelink communication. The base station 111 can also configure the maximum transmit power that the UE 110 can use for sidelink communication. This helps prevent interference with other devices and ensures the network operates efficiently.

[0028] The UE110 may include many types of mobile or non-mobile computing devices, including consumer electronics, cellular phones, smartphones, feature phones, tablet computers, wearable computer devices, personal digital assistants (PDAs), pagers, wireless handsets, desktop computers, laptop computers, in-vehicle infotainment (IVI), in-car entertainment (ICE) devices, instrument clusters (ICs), head-up display (HUD) devices, onboard diagnostic (OBD) devices, dashtop mobile equipment (DMEs), mobile data terminals (MDTs), electronic engine management systems (EEMS), electronic / engine control units (ECUs), electronic / engine control modules (ECMs), embedded systems, microcontrollers, control modules, and engine management systems. This includes systems (EMS), networked or "smart" electronic devices, machine-type communication (MTC) devices, machine-to-machine (M2M) devices, Internet of Things (IoT) devices, and / or similar devices.

[0029] The systems and devices of Network Example 100 may operate in accordance with one or more communication standards, such as the 4th generation (4G) (e.g., Long-Term Evolution, LTE)), 5th generation (5G) (e.g., New Radio, NR) and / or other communication standards of the 3rd Generation Partnership Project (3GPP). Additionally or alternatively, one or more of the systems and devices of Network Example 100 may operate in accordance with other communication standards and protocols described herein, including future versions or generations of 3GPP standards (e.g., 6th generation (6G) standards), IEEE standards (e.g., Wireless Metropolitan Area Network (WMAN), Worldwide Interoperability for Microwave Access (WiMAX)), and others.

[0030] In some embodiments, a RAN node such as base station 111 may be a next-generation (NG) RAN or 5G RAN, an evolved-UMTS terrestrial RAN (E-UTRAN), or a conventional RAN such as UTRAN or GERAN. As used herein, the terms "NG RAN," etc., may refer to a RAN node operating in an NR or 5G system, and the terms "E-UTRAN," etc., may refer to a RAN node operating in an LTE or 4G system. A RAN node may be further connected to a core network (CN) via an NG interface. The CN may comprise a plurality of network elements configured to provide various data and telecommunications services to customers / subscribers (e.g., users of UE110) connected to the CN via the RAN.

[0031] Figure 2 is a schematic diagram 200 illustrating resource selection for sidelink data transmission over an unlicensed band according to several aspects of this description. As described above in relation to the detection and resource selection procedure 106, in mode 2 resource allocation, a transmitting UE participating in sidelink communication (e.g., transmitting UE 110-1 in Figure 1) can autonomously allocate resources for transmission and retransmission if the resources are not being used by other UEs with higher-priority traffic, as determined by a detection procedure performed within the detection window 201. The transmitting UE may then select and occupy resources within the selection window 202 for an appropriate amount of time until a reselection event is triggered.

[0032] The detection procedure starts with the transmitting UE determining a selection window and all potential candidate resources within the selection window 202. The selection of resources for its (re)transmission by the transmitting UE is based on the detection results in the detection window 201 for the potential candidate resources within the selection window 202. The selection window 202 is determined to be bounded by a time frame (n + T1, n + T2), where n is the trigger time of the resource allocation, n + T1 is the lower limit of the selection window 202, and n + T2 is the upper limit of the selection window 202. As an example, the trigger time n can be the arrival time of the transport block. There are two processing times (Tproc0 and Tproc1) before and after the trigger time n, which can respectively refer to the time required by the physical layer and MAC layer to process inter-layer information exchange and prepare the sidelink physical channel. In resource allocation mode 2, the transmitting UE may perform continuous detection. When a resource selection event is triggered at the trigger time n in the transmitting UE, the transmitting UE considers its most recent detection results within the detection window 201 before the trigger time n (e.g., between 1100 ms and 100 ms) for resource selection. The detection results at the far boundary n - T0 (e.g., 1100 ms) of the detection window 201 are useful for identifying reserved resources by other UEs for periodic traffic, and the detection results at the near boundary n - T proc,0 (e.g., 100 ms) of the detection window 201 are particularly useful for aperiodic traffic.

[0033] In some aspects, the lower limit n + T1 of the selection window 202 is determined considering the minimum expected CCA time T CCA_min As a result, the resource candidates can be limited to the resource candidates after the CCA operation is completed, and thus the success rate of SL-U transmission increases. As an example, the lower limit n + T1 is such that T CCA_min ≦T1≦Tproc,1+T CCA_minIt may be determined as follows: Tproc,1 is the processing time required for resource selection for sidelink transmission, and can be in slots or time units. For example, Tproc,1 may be equal to 3, 5, 9, or 17 slots for subcarrier spacings (SCS) of 15, 30, 60, or 120 kHz, respectively. CCA_min This can be calculated based on the Channel Access Priority Class (CAPC) value of the transmitted sidelink data and the current competition window size ("CW_p") of the CCA operation. In some further embodiments, the channel occupancy Roc is also T CCA_min This is included in calculating it.

[0034] In some embodiments, the upper limit n+T2 of the selection window 202 is the maximum expected CCA time T. CCA_max This is determined considering the following, and as a result, the resource candidates may be expanded to take into account the time it takes for the CCA operation, thus increasing the availability and efficiency of resource selection. As an example, the upper limit n+T2 is T 2,min +T CCA_max ≤T2≦T PDB It may be determined as, here, T 2,min is a default or pre-configured time parameter for the minimum selection period, T PDBは This is the remaining packet delay budget (PDB) used to meet latency requirements. For example, T 2,min This can be equal to 1, 5, 10, or 20 slots. 2,min This may be defined by time instead of slots. CCA_max This can be calculated based on the CAPC value of the transmitted sidelink data and the current competition window size ("CW_p") of the CCA operation. In some further embodiments, the channel occupancy Roc is also T CCA_max This is included when calculating the expected CCA time T. CCA_min and T CCA_max Further details are explained below in relation to the diagram in Figure 3.

[0035] Figure 3 is a schematic diagram illustrating the timing for resource selection based on Clear Channel Assessment (CCA) for SL-U operation in several aspects of this description. CCA operation helps to coordinate spectrum usage across multiple devices and even across different radio access technologies. Different types of CCA operation exist for various communication schemes. Type 1 CCA is used to initiate one or more transmissions within the same channel occupancy time (COT), while Type 2 CCA is used for COT sharing and discovery burst transmissions. Type 2 CCA includes Types 2A, 2B, or 2C, which are performed depending on the length of the COT gap between transmissions. Type 2A CCA is performed for discovery burst transmissions when the COT gap is 25 μs or longer. Type 2B CCA is performed when the COT gap is 16 μs or longer but less than 25 μs. Type 2C CCA is performed when the COT gap is less than 16 μs.

[0036] When the CCA operation is type 1 CCA, the transmitting UE must declare the channel available for a delay duration T. d During this time, the system may listen for other potential transmission activity on the channel and then wait for a backoff period before transmitting. An exemplary Type 1 CCA operation may include the steps shown in logic diagram 300: 1) As shown in action 310, initialize the backoff counter N with a random value uniformly distributed between 0 and the current race window size ("CW_p"), 2) As indicated by Action 320, the channel has a delayed duration Td (e.g., 16 μs + m). * Wait for 9μs until it becomes an idle state. 3) Determine whether N is equal to 0, as shown in action 330. 4) If N=0, the transmitting UE is ready to send the sidelink data as scheduled, as indicated by action 360. 5) If N > 0, set N = N - 1 as shown by action 340, 6) Following the decrement of the backoff counter N, the channel is detected for an additional detection slot duration (e.g., 9 μs) as indicated by action 350. If the additional detection slot duration is idle, proceed to action 330 to determine if N has decreased to 0; otherwise, proceed to action 320 and wait for the channel to become clear / idle for another deferral duration Td.

[0037] Postponement period T d This depends on the data priority. For example, the deferral duration T d This involves a fixed period Tf (e.g., 16 μs) and a multiple of an integer m of the detection slot duration (e.g., m *It consists of 9μs. A few m may relate to the CAPC value of the transmitted data. Table 301 shows an example of m values ​​and allowable CW sizes for corresponding CAPC classes. Thus, high-priority traffic (with smaller CAPC values) can detect the channel for a shorter period Td and therefore can take the channel more quickly than low-priority traffic. The backoff counter N is randomly selected by the CCA operation between 0 and the current competition window size ("CW_p") to avoid collisions between multiple transmitters. Without random backoff, two UEs waiting for the channel to become available would start at the same time, resulting in a collision. Using random backoff significantly reduces the likelihood of multiple UEs attempting to access the channel simultaneously. Also, high-priority traffic (with smaller CAPC values) uses smaller CW to gain faster access to the channel, while low-priority traffic uses larger CW, increasing the likelihood of high-priority traffic being transmitted before low-priority traffic. The size of the current competition window CW_p is adjusted based on acknowledgment / negative acknowledgment (ACK / NACK) feedback. For example, CW_p can be set to its minimum value after receiving positive ACK / NACK feedback and doubled to its maximum value if negative ACK / NACK is received. Thus, the channel is used more aggressively for efficiency when transmission is successful and less aggressively to reduce collisions with other transmissions when transmission fails.

[0038] Therefore, in some embodiments, the minimum expected CCA time T described above is CCA_min This consists of a deferral duration Td and a backoff duration Tb. For example, T CCA_min The value is set to Td+Tb, and Td is 16μs+m * It is 9 μs. However, the estimated backoff duration Tb depends on the individual transmission conditions. Assuming that all detection slots are detected as idle during action 350 of the type 1 CCA operation shown in logic diagram 300, the estimated backoff duration Tb is N *It is 9 μs. Therefore, T CCA_min is 16μs+m * 9μs+N * It can be set to 9μs. However, in various user scenarios, the busier a channel is, the more likely it is to be detected as occupied by action 350, and therefore requires a longer CCA operation, resulting in a longer backoff duration Tb. Thus, in some further embodiments, the estimation of the expected backoff duration Tb can be extended by including the channel occupancy rate Roc, which represents the ratio of detection slots considered busy / occupied. As an example, T CCA_min is 16μs+m * 9μs+N * It can be set to 9 μs / (1-Roc).

[0039] In one embodiment, Received Signal Strength Indicator (RSSI) measurement is performed for sidelink transmission. RSSI measurement may be configured or preconfigured by the base station using a channel occupancy threshold (e.g., channelOccupancyThreshold) and a measurement window (e.g., reportInterval). The configuration may be included as part of the reporting configuration (e.g., RRC IE reportConfig). Channel occupancy Roc is defined using the RSSI measurement results. Specifically, channel occupancy Roc is defined as the proportion of samples measured within the measurement window that have an RSSI higher than the channel occupancy threshold. For example, channel occupancy Roc may be the proportion of samples within a configurable measurement window, e.g., 160 ms, that have a received signal power level greater than a configurable threshold (e.g., configured in the range of 0 to -76 dBm), or samples preconfigured to a default value (e.g., -72 dBm).

[0040] In some alternative embodiments, channel occupancy Roc is defined using the measurement results of the CCA operation. Specifically, channel occupancy Roc is defined as the percentage of detection slots identified as busy / occupied out of the total detection slots within a given time window. For example, if 9 detection slots are identified as busy slots within a time window of 20 detection slots, the channel occupancy Roc is 45%. A detection slot can be identified as busy / occupied if the energy received during at least 4 μs of a 9 μs detection slot meets a threshold.

[0041] Similarly, the maximum CCA time T as described above CCA_max It can also be set to Td+Tb, where Td is 16μs+m * The duration is 9 μs, and Tb is N in some embodiments. * As 9μs, in some alternative embodiments, N * It is estimated as 9 μs / (1-Roc). The expected backoff duration Tb may be further extended to the current competition window CW_p, or additionally, the channel occupancy Roc may be taken into account as CW_p / (1-Roc), thereby potentially including more available candidate resources in resource selection. Thus, the maximum CCA time T CCA_max is 16μs+m * 9μs+CW_p or 16μs+m * It can be set to 9μs + CW_p / (1-Roc).

[0042] Figure 4 is a logical flow diagram 400 illustrating the process for selecting and excluding resources based on CCA operation for SL-U according to several aspects of this description. As shown by action 410, a selection window is determined and potential candidate resources within the selection window are identified. The determination of the selection window is described above in relation to Figures 1 to 3. The selection window, represented by (n+T1, n+T2), is bounded by the expected CCA time for type 1 CCA operation, and thus potential candidate resources are limited to time slots after the expected completion of type 1 CCA operation. This can improve the transmission success rate of SL-U transmissions.

[0043] As shown by action 420, the detection window preceding the selection window is determined. (n-T0, n-T proc,0 The detection window, represented by ), is used to receive channel occupancy information such as resource reservations by other UEs. Detection results at the far end of the detection window n-T0 (e.g., 1100ms) are useful for identifying resources reserved by other UEs for periodic traffic, while the near end of the detection window nT proc,0 Detection results at (e.g., 100ms) are particularly useful for non-periodic traffic.

[0044] As indicated by actions 430-470, resource reservations received from other UEs during the detection window are decoded to be excluded from candidate resources if certain criteria are met. As indicated by action 430, the UE obtains an initial RSRP threshold. In some embodiments, the initial RSRP threshold is configured or preconfigured per resource pool. In some additional or alternative embodiments, the initial RSRP threshold is based on the priority prio_TX of the transmitted data. For example, if the transmitted data has a high priority, a higher initial RSRP threshold may be used. A higher RSRP threshold will result in fewer candidate resources being excluded from selection, and therefore more tuned candidate resources being available. Conversely, if the transmitted data has a low priority, a lower initial RSRP threshold may be used.

[0045] As indicated by action 440, the UE sets an initial set of candidate resources for SL-U transmission "S A In some aspects, the UE obtains the initial candidate resource S to form a set of adjusted (e.g., remaining) candidate resources. AFrom this, resources that overlap with RB sets having consistent LBT failures are excluded. RB sets having consistent LBT failures are indicated from higher layers (e.g., MAC layers) to the physical layer. Consistent LBT failures are detected and indicated for each RB set by counting LBT failure indications for SL-U transmissions from the physical layer to the MAC layer. Then, when the LBT failure indications reach a (pre-configured) threshold, a consistent LBT failure is determined by the MAC layer. MAC entities may be configured by RRC with a consistent LBT failure recovery procedure. RRC configures parameters used for detecting consistent sidelink LBT failures for operation with shared spectral channel access. For example, a maximum LBT failure count (lbt-FailureInstanceMaxCount) and a failure detection timer (e.g., lbt-FailureDetectionTimer) may be configured in a failure recovery configuration (e.g., lbt-FailureRecoveryConfig) and used to determine a consistent LBT failure.

[0046] As indicated by Action 450, the adjusted (e.g., remaining) set of candidate resources is further filtered to exclude resources if the UE receives an SCI reserving a resource during the detection window, and the RSRP associated with the SCI is greater than the RSRP threshold. In some additional or alternative embodiments, the initial RSRP threshold is based on the priority prio_RX of an SCI received from another UE. For example, if the UE receives an SCI from another UE reserving a resource with high priority (e.g., during the detection window), the UE may initially use a lower RSRP threshold. Thus, high-priority resources are more likely to be excluded from resource selection, thereby reducing interference with high-priority transmissions from other UEs. Alternatively, if the UE receives only SCIs from other UEs reserving resources for SL-PRS with low priority, the UE may choose to use a higher initial RSRP threshold so that the resource is more likely to be an available candidate resource.

[0047] As shown by action 460, the adjusted set of candidate resources is the initial candidate resource S A If the RSRP threshold is smaller than the threshold percentage "X", the resource pool is rearranged as indicated by action 470, and the MAC layer selects a resource with the updated resource pool. As an example of rearranging a resource pool, the RSRP threshold is increased by the RSRP adjustment value and the process is repeated. Otherwise, the adjusted candidate resources are reported to the upper layer (e.g., the MAC layer) for subsequent resource selection and SL-U data transmission, as indicated by action 480. The threshold percentage value X may be configured or pre-configured. For example, after excluding reserved resources from the selection window (as illustrated and described in relation to actions 440 and 450), the MAC layer may select a resource from the set of adjusted candidate resources. The selection may be random or based on timing, traffic priority, and / or measurement conditions. For example, resources may be randomly selected based on traffic priority from the 20% of best resources with a measured RSRP smaller than the (pre-configured) threshold percentage. If the remaining resources after the elimination steps of actions 440 and 450 are less than 20% of all resources in the selection window, the UE relaxes the RSRP threshold (in 3dB increments) until at least 20% (or 35, 50% based on traffic priority) of all resources in the selection window are obtained for resource allocation. The final selection of resources is made at the UE's MAC layer, receiving the set of unoccupied resources from the physical layer.

[0048] Figure 5 shows a schematic diagram of the resource pool in the selection window, illustrating the selection and exclusion of resources based on CCA operations for the SL-U in some embodiments of this description. In some embodiments, as described above in relation to action 440 in Figure 4, if the UE receives information about an RB set having consistent LBT failures, the RB set is excluded from the resource pool. In some embodiments, an RB set is identified as one or more subchannel frequencies that are not time-limited. Therefore, multiple time slots can be excluded from potential candidate resources without requiring multiple CCA operations.

[0049] Figure 6 is a process flow diagram 600 illustrating the process by which a transmitting UE (e.g., transmitting UE 110-1, which is described throughout this description) performs communication on the SL-U based on CCA operation, according to several aspects of this description.

[0050] As indicated by action 610, the transmitting UE detects resource reservations from other UEs and selects a resource for SL-U transmission. Resource selection may take into account the parameters and conditions of the CCA operation to be performed. In one embodiment, as indicated by action 611, the selection window determination takes into account the expected CCA operation time that the CCA operation may take. As described above, for a type 1 CCA, the expected CCA operation time includes the deferral duration Td and the backoff period Tb. d This depends on the data priority. For example, the deferral duration T d This involves a fixed period Tf (e.g., 16 μs) and a multiple of an integer m of the detection slot duration (e.g., m * It can consist of 9 μs. A few m may be related to the CAPC value of the transmitted data. The estimated backoff period Tb depends on the individual transmission conditions. Assuming all detection slots were clear during Type 1 CCA operation, the estimated backoff duration Tb is N * The time interval is 9 μs, and N is a randomly selected integer between 0 and the current competition window. Therefore, the minimum expected CCA operating time T is 9 μs.CCA_min is 16μs+m * 9μs+N * It can be set to 9μs. However, in various user scenarios, the busier a channel is, the more likely it is to be detected as occupied, and therefore requires a longer CCA operation, resulting in a longer backoff duration Tb. Thus, in some further embodiments, the estimation of the expected backoff duration Tb can be extended by including the channel occupancy rate Roc, which represents the ratio of detection slots considered busy / occupied. As an example, T CCA_min is 16μs+m * 9μs+N * It can be set to 9 μs / (1-Roc). CCA_min This can be used to limit the lower limit of the selection window, thereby reducing transmission failures due to imperfections in the CCA operation. In another embodiment, as indicated by action 612, the candidate resource set can be refined by excluding candidates based on consistent LBT failures. One or more RB sets with consistent LBT failures are indicated from the upper layer (e.g., the MAC layer) to the physical layer. Consistent LBT failures are detected and indicated for each RB set by counting LBT failure indications from the physical layer to the MAC layer. The MAC layer then determines that a consistent LBT failure is present when the LBT failure indications reach a (pre-configured) threshold.

[0051] As indicated by action 620, a CCA operation is performed for the SL-U. The CCA operation may be a Type 1 CCA for initiating one or more transmissions within the same channel occupancy time (COT). Alternatively or additionally, the CCA operation may include a Type 2 CCA used for COT sharing and discovery burst transmissions. Type 2 CCAs include Types 2A, 2B, or 2C, which are performed depending on the length of the COT gap between transmissions. A Type 2A CCA is performed for discovery burst transmissions when the COT gap is 25 μs or longer. A Type 2B CCA is performed when the COT gap is 16 μs or longer but less than 25 μs. A Type 2C CCA is performed when the COT gap is less than 16 μs. When the CCA operation is a Type 1 CCA, the transmitting UE may listen for other potential transmitting activity on the channel for a deferral duration Td before declaring the channel available, and then wait for a backoff period Tb before transmitting.

[0052] As indicated by action 630, after selecting a resource, the sending UE sends data to another UE using the resource selected for the SL-U.

[0053] Figure 7 is a logical flow diagram 700 illustrating the process by which a transmitting UE (e.g., transmitting UE 110-1, as described throughout this description) receives shared channel occupancy time (COT) information and selects resources for the SL-U, according to several aspects of this description.

[0054] In action 710, shared channel occupancy time (COT) information is transmitted from UE 110-2, the initializing UE, to the transmitting UE 110-1. The shared COT information includes information about the shared COT initiated by the initializing UE. In some embodiments, the shared COT information includes the duration of the COT and one or more UE identifiers of the initializing UE 110-2. In some embodiments, the shared COT information may further include a priority threshold for using the COT. In some embodiments, the shared COT information is transmitted in Sidelink Control Information (SCI) format. The shared COT information may be transmitted over a Physical Sidelink Control Channel (PSCCH). In some embodiments, the shared COT information may be communicated exclusively between the initializing UE 110-2 and the transmitting UE 110-1 (unicast). In other embodiments, the initializing UE 110-2 may transmit shared COT information to be received by all candidate UEs within the wireless transmission range of the initializing UE 110-2 (broadcast), or it may transmit shared COT information to be received by a set of receivers that meet certain conditions (groupcast).

[0055] In action 720, the SCI containing the shared COT information may be decoded and sent from the physical layer of UE110-1 to the MAC layer. Based on the shared COT information, and by evaluating, for example, the availability and priority of MAC-CE and / or logical channels for UE110-1 and / or other candidate UEs based on the shared COT information, it is determined whether UE 110-1 can share the COT.

[0056] In action 730, a resource is selected or reselected for shared COT transmission from the transmitting UE110-1 to the initializing UE110-2. The resource selection window for SL-U has a start time and an end time. The end time is not later than the remaining COT duration or the remaining PDB duration of the COT.

[0057] In action 740, data is sent from UE110-1 to UE110-2 using resources selected or re-selected on the shared COT.

[0058] Figure 8 shows a schematic diagram 800 of the resource pool within a selection window 202, indicating a transmitting UE (e.g., transmitting UE 110-1, described throughout this description) selecting resources for SL-U transmission using a shared COT, according to some aspects of this description. In addition to, or instead of, the various limitations of the detection window as already described, in some aspects the selection window 202 is also bounded by the remaining COT duration 804. Thus, in some aspects the selection window 202 is determined as the minimum of PDB 803 and the remaining COT duration 804. Thus the selection window 202 is limited by the COT duration 804, and as a result, the sidelink transmission for the initializing UE can be completed during the remaining COT duration 804. Resource selection may be random, or it may be based on timing, traffic priority, and / or measurement conditions. For example, resources may be randomly selected from available candidate resources (e.g., R1, R2, R3, and R4 in the figure). Alternatively, to better utilize the shared COT, earlier resources (e.g., R1, R2) can be selected over later resources (e.g., R3, R4). If the remaining resources after the exclusion procedure are below a threshold, a resource pool reallocation may be performed as described above.

[0059] Figure 9 shows a process flow diagram 900 illustrating the process by which a transmitting UE (e.g., transmitting UE 110-1, which is described throughout this description) transmits data on an SL-U using a shared COT, according to some aspects of this description.

[0060] As indicated by action 910, shared channel occupancy time (COT) information is received from the initializing UE to the transmitting UE. The shared COT information includes information about the shared COT initiated by the initializing UE. In some embodiments, the shared COT information includes the duration of the COT and one or more of the initializing UE's UE identifiers. In some embodiments, the shared COT information is transmitted in Sidelink Control Information (SCI) format. The shared COT information may be transmitted over a Physical Sidelink Control Channel (PSCCH). The shared COT information may be decoded and sent from the physical layer to the MAC layer. A determination of whether the transmitting UE can use the shared COT based on the shared COT information is made, for example, by evaluating the availability and priority of MAC-CE and / or logical channels for the transmitting UE based on the shared COT information.

[0061] As indicated by action 920, if the sending UE determines that a shared COT is available, a resource is selected or re-selected for sending the shared COT from the sending UE to the initializing UE. The resource selection window is determined by an end time that is not later than the remaining COT duration or the remaining PDB duration of the COT.

[0062] As indicated by action 930, data is sent from the sending UE to the initializing UE using resources selected or re-selected on the shared COT.

[0063] Figure 10 is a diagram illustrating an example of the components of device 1000 in one or more implementation forms described herein. Device 1000 or its components may also be or be included in a UE such as the transmitting UE 110-1, as described throughout this disclosure. As described, device 1000 may be configured to perform detection and resource (re)selection procedures based on CCA operation, including setting a selection window considering the expected CCA operation time and / or excluding RBs that are experiencing consistent LBT failures as indicated by the MAC layer. In some alternative or additional embodiments, device 1000 receives shared COT information from the COT-shared initialization device and performs resource selection / reselection procedures using a selection window bounded by the remaining duration of the shared COT. Device 1000 may then, after a type 2A / 2B / 2C CCA, transmit the shared COT to the initialization device over the SL-U.

[0064] In some implementations, device 1000 may include, at least as shown, a single, integrated application circuit 1002, a baseband circuit 1004, an RF circuit 1006, a front-end module (FEM) circuit 1008, one or more antennas 1010, and a power management circuit (PMC) 1012. In some implementations, device 1000 may include fewer elements (for example, a RAN node may not utilize the application circuit 1002 and instead include a processor / controller that processes IP data received from a CN such as a 5GC or an evolved packet core (EPC)). In some implementations, device 1000 may include additional elements such as memory / storage, a display, a camera, sensors (including one or more temperature sensors, such as a single temperature sensor or multiple temperature sensors in different locations within device 1000), or input / output (I / O) interfaces. In other implementations, the components described below may be included in two or more devices (for example, the above circuits may be included separately in two or more devices in a cloud RAN (C-RAN) implementation).

[0065] The application circuit 1002 may include one or more application processors. For example, the application circuit 1002 may include, but is not limited to, one or more single-core processors or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled to memory / storage or may include memory / storage and may be configured to execute instructions stored in memory / storage to enable various applications or operating systems to run on device 1000. In some implementations, the processor of the application circuit 1002 may process IP data packets received from CN.

[0066] The baseband circuit 1004 may include, but is not limited to, one or more single-core processors or multi-core processors. The baseband circuit 1004 may include one or more baseband processors or control logic that process baseband signals received from the receiving signal path of the RF circuit 1006 and generate baseband signals for the transmitting signal path of the RF circuit 1006. The baseband circuit 1004 can interface with the application circuit 1002 for generating and processing baseband signals and for controlling the operation of the RF circuit 1006. For example, in some implementations, the baseband circuit 1004 may include a 3G baseband processor 1004A, a 4G baseband processor 1004B, a 5G baseband processor 1004C, or other baseband processors (one or more) 1004D of existing, developing, or future generations (e.g., 2G, 6G, etc.). The baseband circuit 1004 (for example, one or more of the baseband processors 1004A to 1004D) can handle various radio control functions that enable communication with one or more radio networks via the RF circuit 1006. In other implementations, some or all of the functions of the baseband processors 1004A to 1000D may be contained in modules stored in memory 1004G and executed via the Central Processing Unit (CPU) 1004E. Radio control functions may include, but are not limited to, signal modulation / demodulation, coding / decoding, and radio frequency shifting. In some implementations, the modulation / demodulation circuit of the baseband circuit 1004 may include Fast Fourier Transform (FFT), precoding, or constellation mapping / demapping functions. In some implementations, the encoder / decoder circuit of the baseband circuit 1004 may include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity check (LDPC) encoder / decoder functionality. The implementation forms of modulation / demodulation and encoder / decoder functionality are not limited to these examples, and other implementation forms may include other suitable functionalities.

[0067] In some implementations, the baseband circuit 1004 may include one or more audio digital signal processors (DSPs) 1004F. The audio DSPs 1004F may include elements for compression / decompression and echo cancellation, and in other implementations, may include other suitable processing elements. The components of the baseband circuit may be suitably combined within a single chip, a single chipset, or, in some implementations, arranged on the same circuit board. In some implementations, some or all of the components constituting the baseband circuit 1004 and the application circuit 1002 may be integrated, for example, on a system on a chip (SOC).

[0068] In some implementations, the baseband circuit 1004 can provide communication compatible with one or more wireless technologies. For example, in some implementations, the baseband circuit 1004 can support communication with NG-RAN, Evolutionary Universal Terrestrial Radio Access Network (EUTRAN), or other Wireless Metropolitan Area Networks (WMAN), Wireless Local Area Networks (WLAN), Wireless Personal Area Networks (WPAN), etc. An implementation in which the baseband circuit 1004 is configured to support wireless communication of two or more wireless protocols can be called a multimode baseband circuit.

[0069] The RF circuit 1006 can enable communication with a wireless network using modulated electromagnetic radiation over a non-solid medium. In various implementations, the RF circuit 1006 may include switches, filters, amplifiers, etc., to facilitate communication with the wireless network. The RF circuit 1006 may include a receive signal path that includes a circuit to downconvert the RF signal received from the FEM circuit 1008 and provide the baseband signal to the baseband circuit 1004. The RF circuit 1006 may also include a transmit signal path that includes a circuit to upconvert the baseband signal provided by the baseband circuit 1004 and provide the RF output signal to the FEM circuit 1008 for transmission.

[0070] In some implementations, the receive signal path of the RF circuit 1006 may include a mixer circuit 1006A, an amplifier circuit 1006B, and a filter circuit 1006C. In some implementations, the transmit signal path of the RF circuit 1006 may include a filter circuit 1006C and a mixer circuit 1006A. The RF circuit 1006 may also include a combiner circuit 1006D that combines the frequencies used by the mixer circuit 1006A in the receive signal path and the transmit signal path. In some implementations, the mixer circuit 1006A in the receive signal path may be configured to downconvert the RF signal received from the FEM circuit 1008 based on the combined frequency provided by the combiner circuit 1006D. The amplifier circuit 1006B can be configured to amplify the down-converted signal, and the filter circuit 1006C may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal can be provided to the baseband circuit 1004 for further processing. In some implementations, the output baseband signal can be a 0-frequency baseband signal, but this is not a requirement. In some implementations, the mixer circuit 1006A in the received signal path can include a passive mixer, but the range of implementations is not limited to this.

[0071] The FEM circuit 1008 may include a receive signal path that may include a circuit configured to operate on an RF signal received from one or more antennas 1010, amplify the received signal, and provide the amplified version of the received signal to the RF circuit 1006 for further processing. The FEM circuit 1008 may also include a transmit signal path that may include a circuit configured to amplify a signal for transmission provided by the RF circuit 1006, transmitted by one or more of the antennas 1010. In various implementations, amplification through the transmit or receive signal path may occur in the RF circuit 1006 alone, in the FEM circuit 1008 alone, or in both the RF circuit 1006 and the FEM circuit 1008.

[0072] In some implementations, the PMC1012 can manage the power supplied to the baseband circuit 1004. Specifically, the PMC1012 can control power source selection, voltage scaling, battery charging, or DC-DC conversion. When device 1000 is battery-powered, for example, when this device is included in the UE, the PMC1012 can often be included. The PMC1012 can enhance power conversion efficiency while providing desirable implementation size and thermal characteristics. Figure 10 shows the PMC1012 coupled only to the baseband circuit 1004. However, in other implementations, the PMC1012 may be coupled additionally or instead to other components, including but not limited to the application circuit 1002, RF circuit 1006, or FEM circuit 1008, to perform similar power management operations.

[0073] The processors of the application circuit 1002 and the baseband circuit 1004 can be used to execute elements of one or more instances of the protocol stack. For example, the processors of the baseband circuit 1004 can be used alone or in combination to execute Layer 3, Layer 2, or Layer 1 functionality, while the processors of the baseband circuit 1004 can utilize data received from these layers (e.g., packet data) to further execute Layer 4 functionality (e.g., the Transmission Communication Protocol (TCP) layer and the User Datagram Protocol (UDP) layer). As referred to herein, Layer 3 may comprise the RRC layer, Layer 2 may comprise the medium access control (MAC) layer, the radio link control (RLC) layer, and the data convergence protocol (PDCP) layer, and Layer 1 may comprise the physical (PHY) layer of the UE / RAN node.

[0074] Figure 11 shows an exemplary interface of a baseband circuit configuration in one or more implementation forms described herein. As described above, the baseband circuit 1004 in Figure 10 may comprise processors 1004A to 1004E and memory 1004G utilized by these processors. Processors 1004A to 1004E may be collectively referred to as the baseband processor. Each of the processors 1004A to 1004E may include memory interfaces 1104A to 1104E for sending and receiving data to and from memory 1004G. In some embodiments, the baseband circuit 1004 or its components, such as the baseband processors, may also be or be included in a UE, such as a transmitting UE 110-1 or a receiving UE 110-2, as described throughout this disclosure.

[0075] The baseband circuit 1004 may further include one or more interfaces for communicative coupling with other circuits / devices, such as a memory interface 1112 (e.g., an interface for transmitting / receiving data to and from memory outside the baseband circuit 1004), an application circuit interface 1114 (e.g., an interface for transmitting and receiving data to and from application circuit 1002 in Figure 10), an RF circuit interface 1116 (e.g., an interface for transmitting / receiving data to and from RF circuit 1006 in Figure 10), a wireless hardware connection interface 1118 (e.g., an interface for transmitting and receiving data to and from near-field communication (NFC) components, Bluetooth® components, Wi-Fi® components, and other communication components), and a power management interface 1120 (e.g., an interface for transmitting and receiving power or control signals to and from PMC 1012).

[0076] The embodiments herein may include subject matter such as methods, means for performing actions or blocks of those methods, and at least one machine-readable medium containing executable instructions that, when executed by a machine (such as a processor with memory, an Application-Specific Integrated Circuit (ASIC), or a Field Programmable Gate Array (FPGA)), cause the machine to perform actions of a method or apparatus or system for simultaneous communication using the multiplexing techniques described in the embodiments and embodiments.

[0077] Embodiment 1 is a device for a UE, comprising memory and a processor coupled to the memory, wherein when the processor executes instructions stored in memory, it causes the UE to detect and select resources based on a clear channel assessment (CCA) operation performed for side-link communication (SL-U) over an unlicensed band, to perform the CCA operation for the SL-U, and to transmit data to another UE using the resources selected for the SL-U.

[0078] Example 2 is an apparatus that includes the subject matter of Example 1, and resource selection includes determining a resource selection window based on the expected CCA time of the CCA operation.

[0079] Example 3 is an apparatus that incorporates the subject matter of Example 2, in which the expected CCA time for CCA operation is calculated based on the channel access priority class (CAPC) value of the transmitted data and the current competition window size ("CW_p") for CCA operation.

[0080] Example 4 is an apparatus that includes the subject matter of any of Examples 2 to 3, wherein the resource selection window has a lower limit such as the expected CCA time and the sum of the expected CCA time and the processing time Tproc,1 required for resource selection for SL-U.

[0081] Example 5 is an apparatus that includes the subject matter of Example 3, where the expected CCA time of the CCA operation is the sum of the deferral duration of the CCA operation based on the CAPC value and the estimated backoff period of the CCA operation related to the current competition window size ("CW_p").

[0082] Example 6 is an apparatus that includes the subject matter of Example 5, and the estimated backoff period of the CCA operation is N * This is the detection slot period, where N is a backoff counter randomly selected by the CCA operation between 0 and the current conflict window size ("CW_p").

[0083] Example 7 is an apparatus that includes the subject matter of either Example 3 or 5, and the expected CCA time for CCA operation is calculated based on the channel occupancy rate (Roc).

[0084] Example 8 is an apparatus that includes the subject matter of Example 7, in which channel occupancy (Roc) is defined as the percentage of samples in which the received signal strength indicator (RSSI) measurements measured within the measurement window satisfy the channel occupancy threshold.

[0085] Example 9 is an apparatus that incorporates the subject matter of Example 7, where channel occupancy (Roc) is defined as the percentage of a total number of sensing slots within a predetermined time window that are identified as being occupied by CCA operations.

[0086] Example 10 is an apparatus that includes the subject matter of Example 7, and the expected CCA time for the CCA operation is 16 μs + m * 9μs+N * It is calculated as 9μs / (1-Roc), where m is an integer related to the CAPC value and N is another integer randomly selected by the CCA operation between 0 and the current competition window size ("CW_p").

[0087] Example 11 is a device that incorporates the subject matter of Example 2, wherein the resource selection window has an upper limit that is greater than the sum of the minimum selection period and the expected CCA time, but does not exceed the remaining packet delay budget (PDB).

[0088] Example 12 is an apparatus that includes the subject matter of Example 11, where the expected CCA time is set as Td + CW_p, where Td is the deferral period for the CCA operation and CW_p is the current competition window size for the CCA operation.

[0089] Example 13 is an apparatus that includes the subject matter of Example 11, where the expected CCA time is set as Td + CW_p / (1 - Roc), where Td is the delay period for the CCA operation, CW_p is the current competition window size for the CCA operation, and Roc is the channel occupancy.

[0090] Example 14 is an apparatus that includes the subject matter of Example 1, wherein resource selection includes determining a resource selection window, obtaining an initial set of candidate resources based on consistent listen-before-talk (LBT) failure indications, and eliminating candidates to form a refined set of candidate resources.

[0091] Example 15 is an apparatus that incorporates the subject matter of Example 14, and consistent LBT failure indication is provided from the MAC layer to the physical layer for each RB set.

[0092] Embodiment 16 is an apparatus that includes the subject matter of Embodiment 15, wherein the processor is further configured to cause the UE to determine the number of remaining candidate resources in a tuned set of candidate resources that is less than a default threshold, to notify the MAC layer of the shortage of candidates, and to cause the MAC layer to perform resource pool reselection.

[0093] Embodiment 17 is a device comprising the subject matter of Embodiment 1, wherein the processor is configured to cause the UE to receive sidelink control information (SCI) from the initializing UE, which includes shared channel occupancy time (COT) information, the shared COT information including information on shared COTs initiated by the initializing UE. Resource selection includes determining a resource selection window having a start time and an end time, the end time not being later than the remaining COT duration and the remaining packet delay budget (PDB) of the COT.

[0094] Example 18 is a method for operating a UE, which includes determining a resource selection window for sidelink communication (SL-U) over an unlicensed band, obtaining an initial set of candidate resources in the resource selection window, excluding one or more resource blocks from the initial set of candidate resources to form a reconciled set of candidate resources based on consistent listen-before-talk (LBT) failure indications from the MAC layer, selecting a resource from the reconciled set of candidate resources, and sending data to another UE using the selected resource.

[0095] Example 19 is a method that includes the subject matter of Example 18 and further includes determining the number of remaining candidate resources in a set of adjusted candidate resources that is less than a default threshold, notifying the MAC layer of the shortage of candidates, and having the MAC layer perform resource pool reselection.

[0096] Embodiment 20 is a baseband processor for a UE, comprising memory and a processor coupled to the memory, wherein when the processor executes an instruction stored in memory, it causes the UE to receive sidelink control information (SCI) from the initializing UE, which includes shared channel occupancy time (COT) information, the shared COT information including information on a shared COT initiated by the initializing UE; causes the UE to determine a resource selection window for sidelink communication (SL-U) on the unlicensed spectrum using an end time no later than the remaining COT duration or the remaining packet delay budget (PDB); causes the UE to select resources for SL-U during the resource selection window; and causes the UE to transmit data to the initializing UE using the selected resources for SL-U.

[0097] Example 21 is a method comprising any of the actions or combinations of actions that are fully described in the “Modes for Carrying Out the Invention” section of this specification.

[0098] Example 22 is a method that is fully described by reference to each or any combination thereof of the figures contained herein, or by reference to each or any combination thereof of the paragraphs “Modes for Carrying Out the Invention”.

[0099] Example 23 is a user device configured to perform any of the actions or combinations of actions that are included in the user device as well described in the “Modes for Carrying Out the Invention” of this specification.

[0100] Example 24 is a network node configured to perform any or a combination of any of the actions that are included in a network node as well described in the “Modes for Carrying Out the Invention” of this specification.

[0101] Example 25 is a non-volatile computer-readable medium for storing instructions, which, when executed, results in the execution of any of the actions or combinations of actions that are fully described in the “Modes for Carrying Out the Invention” of this Specified Specification.

[0102] Example 26 is a baseband processor for a user device configured to perform any or a combination of any of the actions that are included in the user device as well described in the “Modes for Carrying Out the Invention” of this specification.

[0103] Example 27 is a baseband processor of a network node configured to perform any or a combination of any of the actions that are included in user equipment as well described in the “Modes for Carrying Out the Invention” of this Specified Specification.

[0104] The above description of the illustrated embodiments, implementations, and aspects of the disclosed subject matter, including the contents of the abstract, is not intended to be exhaustive or to limit the disclosed aspects to the exact forms disclosed. Specific embodiments, implementations, and aspects are described herein for illustrative purposes, but those skilled in the art will see that various modifications are possible within the scope of such embodiments, implementations, and aspects.

[0105] In this regard, while the disclosed subject matter has been described in relation to various embodiments, implementations, and aspects and corresponding drawings, it should be understood that other similar embodiments may be used, or modifications and additions may be made to the disclosed subject matter, in order to perform the same, similar, alternative, or substitute functions as the subject matter, without departing from the disclosed subject matter. Accordingly, the disclosed subject matter should not be limited to any single embodiment, implementation, or aspect described herein, but rather should be interpreted in accordance with the breadth and scope of the appended claims below.

[0106] Specifically, with respect to the various functions performed by the aforementioned components or structures (assemblies, devices, circuits, systems, etc.), the terms used to describe such components are intended to correspond to any component or structure that performs a particular function of the described component (e.g., functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function of the exemplary implementation of the invention illustrated herein, unless otherwise specified. Furthermore, while specific features may be disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations so as to be desirable and advantageous for any given or specific application.

[0107] As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or it is clear from the context, “X uses A or B” is intended to mean any of all possible permutations. That is, “X uses A,” “X uses B,” or “X uses both A and B” all satisfy the condition “X uses A or B.” In addition, the articles “a” and “an” used in this application and the attached claims should generally be interpreted as meaning “one or more” unless otherwise specified or it is clear from the context that they refer to a singular form. Furthermore, when “including,” “includes,” “having,” “has,” “with,” or their variations are used in either the modes of carrying out the invention or the claims, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, in situations where one or more numbered items (e.g., "the first X," "the second X," etc.) are being described, these one or more numbered items may generally be distinct or identical, but in some situations the context may indicate that the one or more numbered items are distinct or identical.

[0108] It is well understood that the use of personally identifiable information should be governed by privacy policies and practices that are generally recognized as meeting or exceeding industry or government requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and handled in a manner that minimizes the risk of unintended or unauthorized access or use, and the nature of authorized use should be clearly indicated to the user.

Claims

1. A device for user equipment (UE), Memory and The system comprises a processor coupled to the memory, and when the processor executes an instruction stored in the memory, the UE, For sidelink communication (SL-U) over unlicensed bands, resources are detected and selected based on the Clear Channel Assessment (CCA) operation performed. Perform the CCA operation for SL-U, A device configured to cause another UE to transmit data using the selected resources for the SL-U.

2. The apparatus according to claim 1, wherein the selection of the resource includes determining a resource selection window based on the expected CCA time of the CCA operation.

3. The apparatus according to claim 2, wherein the expected CCA time for the CCA operation is calculated based on the channel access priority class (CAPC) value of the transmitted data and the current competition window size ("CW_p") of the CCA operation.

4. The apparatus according to any one of claims 2 to 3, wherein the resource selection window has a lower limit such as the expected CCA time and the sum of the expected CCA time and the processing time Tproc,1 required for resource selection for SL-U.

5. The apparatus according to claim 3, wherein the expected CCA time of the CCA operation is the sum of the postponement duration of the CCA operation based on the CAPC value and the estimated backoff period of the CCA operation related to the current competition window size ("CW_p").

6. The estimated backoff period for the CCA operation is N ＊ The apparatus according to claim 5, wherein the detection slot period is a backoff counter randomly selected by the CCA operation between 0 and the current competition window size ("CW_p").

7. The apparatus according to claim 3 or 5, wherein the expected CCA time of the CCA operation is calculated based on the channel occupancy rate (Roc).

8. The apparatus according to claim 7, wherein the channel occupancy rate (Roc) is defined as the percentage of samples in which the received signal strength indicator (RSSI) measurements taken within the measurement window satisfy the channel occupancy threshold.

9. The apparatus according to claim 7, wherein the channel occupancy rate (Roc) is defined as the proportion of detection slots identified as being occupied by the CCA operation among a total of several detection slots within a predetermined time window.

10. The expected CCA time for the CCA operation is 16 μs + m ＊ 9μs+N ＊ The apparatus according to claim 7, calculated as 9 μs / (1-Roc), where m is an integer related to the CAPC value and N is another integer randomly selected by the CCA operation between 0 and the current competition window size ("CW_p").

11. The apparatus according to claim 2, wherein the resource selection window has an upper limit that is greater than the sum of the minimum selection period and the expected CCA time, but does not exceed the remaining packet delay budget (PDB).

12. The apparatus according to claim 11, wherein the expected CCA time is set as Td + CW_p, where Td is the delay period for the CCA operation and CW_p is the current competition window size for the CCA operation.

13. The apparatus according to claim 11, wherein the expected CCA time is set as Td + CW_p / (1 - Roc), where Td is the delay period for the CCA operation, CW_p is the current competition window size for the CCA operation, and Roc is the channel occupancy rate.

14. The selection of the aforementioned resources is Determining the resource selection window, The apparatus according to claim 1, comprising: obtaining an initial set of candidate resources based on consistent listen-before-talk (LBT) failure indications; and eliminating candidates to form a refined set of candidate resources.

15. The apparatus according to claim 14, wherein the consistent LBT failure indication is provided from the MAC layer to the physical layer for each RB set.

16. The aforementioned processor provides the UE with: Determine the number of remaining candidate resources in the adjusted set of candidate resources that is smaller than the default threshold. The MAC layer is notified of the lack of candidates. The apparatus according to claim 15, further configured to cause the MAC layer to perform resource pool reselection.

17. The aforementioned processor provides the UE with: The system is configured to receive sidelink control information (SCI) from the initializing UE, which includes shared channel occupancy time (COT) information, wherein the shared COT information includes information on shared COT initiated by the initializing UE. The apparatus according to claim 1, wherein the selection of the resource comprises determining a resource selection window having a start time and an end time, the end time not being later than the remaining COT duration and the remaining packet delay budget (PDB) of the COT.

18. A method for operating user equipment (UE), To determine the resource selection window for side-link communication (SL-U) on unlicensed bands, Obtaining an initial set of candidate resources in the aforementioned resource selection window, Based on consistent Listen Before Talk (LBT) failure indications from the MAC layer, one or more resource blocks are excluded from the initial set of candidate resources in order to form a coordinated set of candidate resources. Selecting a resource from the aforementioned set of adjusted candidate resources, Sending data to another UE using the selected resources, Methods that include...

19. Determining the number of remaining candidate resources in the adjusted set of candidate resources that is smaller than a default threshold, Notifying the MAC layer of the lack of candidates, The MAC layer performs resource pool reselection, The method according to claim 18, further comprising:

20. A baseband processor for user equipment (UE), Memory and The system comprises a processor coupled to the memory, and when the processor executes an instruction stored in the memory, the UE, The initializing UE receives sidelink control information (SCI) that includes shared channel occupancy time (COT) information, wherein the shared COT information includes information on shared COT initiated by the initializing UE. The resource selection window for sidelink communication (SL-U) on the unlicensed spectrum is determined using an end time that is no later than the remaining COT duration or the remaining packet delay budget (PDB) of the COT. During the resource selection window, the user is prompted to select resources for SL-U. A baseband processor configured to cause the initializing UE to transmit data using the selected resources for the SL-U.

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