GOLITSCHEK EDLER VON ELBWART ALEXANDER (DE)
LÖHR JOACHIM (DE)
BASU MALLICK PRATEEK (DE)
WO2021214709A1 | 2021-10-28 |
US20220086908A1 | 2022-03-17 |
3GPP TS 37.213
"NR; Physical layer procedures for control", 3GPP TS 38.213
"NR; Physical layer procedures for data", 3GPP TS 38.214
3GPP TS 38.215
3GPP TS 38.300
3GPP TS 36.843
Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT WHAT IS CLAIMED IS: 1. A user equipment (UE) for sidelink communication, the UE comprising: at least one controller coupled with at least one memory and configured to cause the UE to: select one of an ordered sequence of values corresponding to a plurality of values for use as a maximum contention window size for an associated priority class for use by the UE in determining a contention window size to be used in identifying whether a channel in an unlicensed carrier is clear by a transmission authorization procedure; wherein the UE is authorized to make use of the channel for a sidelink transmission after the controller of the UE uses the determined contention window size, based on the selected value for the maximum contention window size to identify that the channel in the unlicensed carrier as determined using a transceiver is clear for a number of sensing slots in accordance with the determined contention window size; and wherein for subsequent sidelink transmission authorization procedure(s), a determination is made by the controller as to whether the maximum contention window size is updated from which a new current contention window size can be determined for use in identifying using the transceiver whether the channel in the unlicensed carrier to be used for the subsequent sidelink transmissions is clear. 2. The UE in accordance with claim 1, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a no HARQ feedback, the maximum contention window size is updated after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size. 3. The UE in accordance with claim 2, wherein the number of transmission authorization procedures using a particular selected one of the ordered sequence of Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT values corresponding to a particular maximum contention window size is configurable. 4. The UE in accordance with claim 1, wherein after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values, a next one of the ordered sequence of values corresponding to a next higher value for use as a maximum contention window size is selected; when there is no next higher value in the plurality of values for use as the maximum contention window size for the associated priority class, the next one of the ordered sequence of values corresponding to the lowest possible value for use as a maximum contention window size in the ordered sequence of values is selected. 5. The UE in accordance with claim 1, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a NACK-only feedback or an ACK/NACK feedback, the maximum contention window size is updated after a number of NACK feedback for sidelink transmissions within a reference duration has been received, wherein the reference duration comprises sidelink transmission(s) from the beginning of a channel occupancy. 6. The UE in accordance with claim 1, wherein each of the sidelink transmissions has a corresponding type of transmission from a list including unicast, groupcast or broadcast; wherein for a transmission authorization procedure for a channel occupancy including at least some of the types of transmission, the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size is a subset corresponding to a number less than all of the values for one or more of a particular associated priority class. 7. A processor for wireless communication in a user equipment (UE) for sidelink communication, the processor comprising: Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT at least one controller coupled with at least one memory and configured to cause the processor to: select one of an ordered sequence of values corresponding to a plurality of values for use as a maximum contention window size for an associated priority class for use by the UE in determining a contention window size to be used in identifying whether a channel in an unlicensed carrier is clear by a transmission authorization procedure; wherein the UE is authorized to make use of the channel for a sidelink transmission after the controller of the UE uses the determined contention window size, based on the selected value for the maximum contention window size to identify that the channel in the unlicensed carrier as determined using a transceiver is clear for a number of sensing slots in accordance with the determined contention window size; and wherein for subsequent sidelink transmission authorization procedure(s), a determination is made by the controller as to whether the maximum contention window size is updated from which a new current contention window size can be determined for use in identifying using the transceiver whether the channel in the unlicensed carrier to be used for the subsequent sidelink transmissions is clear. 8. The processor in accordance with claim 7, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a no HARQ feedback, the maximum contention window size is updated after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size. 9. The processor in accordance with claim 8, wherein the number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size is configurable. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT 10. The processor in accordance with claim 7, wherein after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values, a next one of the ordered sequence of values corresponding to a next higher value for use as a maximum contention window size is selected; when there is no next higher value in the plurality of values for use as the maximum contention window size for the associated priority class, the next one of the ordered sequence of values corresponding to the lowest possible value for use as a maximum contention window size in the ordered sequence of values is selected. 11. The processor in accordance with claim 7, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a NACK-only feedback or an ACK/NACK feedback, the maximum contention window size is updated after a number of NACK feedback for sidelink transmissions within a reference duration has been received, wherein the reference duration comprises sidelink transmission(s) from the beginning of a channel occupancy. 12. The processor in accordance with claim 7, wherein each of the sidelink transmissions has a corresponding type of transmission from a list including unicast, groupcast or broadcast; wherein for a transmission authorization procedure for a channel occupancy including at least some of the types of transmission, the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size is a subset corresponding to a number less than all of the values for one or more of a particular associated priority class. 13. A method in a user equipment (UE) for sidelink communication, the method comprising: selecting one of an ordered sequence of values corresponding to a plurality of values for use as a maximum contention window size for an associated priority class Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT for use by the UE in determining a contention window size to be used in identifying whether a channel in an unlicensed carrier is clear by a transmission authorization procedure; wherein the UE is authorized to make use of the channel for a sidelink transmission after the UE uses the determined contention window size, based on the selected value for the maximum contention window size, to identify that the channel in the unlicensed carrier is clear for a number of sensing slots in accordance with the determined contention window size; and wherein for subsequent sidelink transmission authorization procedure(s), a determination is made as to whether the maximum contention window size is updated from which a new current contention window size can be determined for use in identifying whether the channel in the unlicensed carrier to be used for the subsequent sidelink transmissions is clear. 14. The method in accordance with claim 13, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a no HARQ feedback, the maximum contention window size is updated after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size. 15. The method in accordance with claim 14, wherein the number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size is configurable. 16. The method in accordance with claim 13, wherein after a number of transmission authorization procedures using a particular selected one of the ordered sequence of values, a next one of the ordered sequence of values corresponding to a next higher value for use as a maximum contention window size is selected; Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT when there is no next higher value in the plurality of values for use as the maximum contention window size for the associated priority class, the next one of the ordered sequence of values corresponding to the lowest possible value for use as a maximum contention window size in the ordered sequence of values is selected. 17. The method in accordance with claim 13, wherein after the number of transmission authorization procedures using the particular selected one of the ordered sequence of values, a next one of the ordered sequence of values is randomly selected from the ordered sequence of values for use as the maximum contention window size for the associated priority class. 18. The method in accordance with claim 13, wherein the sidelink communication has an associated type of feedback; and wherein, when the associated type of feedback is a NACK-only feedback or an ACK/NACK feedback, the maximum contention window size is updated after a number of NACK feedback for sidelink transmissions within a reference duration has been received, wherein the reference duration comprises sidelink transmission(s) from the beginning of a channel occupancy. 19. The method in accordance with claim 18, wherein each transmission authorization procedure is associated with a particular one of a plurality of possible resource pools, where each resource pool corresponds to a different subset of a plurality of resources associated with the unlicensed carrier; wherein the number of transmission authorization procedures used for determining when to update the maximum contention window size associated with the particular one of the plurality of possible resource pools is dependent on the number of transmission authorization procedure associated with the particular resource pool having been transmitted. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT 20. The method in accordance with claim 13, wherein each of the sidelink transmissions has a corresponding type of transmission from a list including unicast, groupcast or broadcast; wherein for a transmission authorization procedure for a channel occupancy including at least some of the types of transmission, the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size is a subset corresponding to a number less than all of the values for one or more of a particular associated priority class. |
Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT From 3GPP TS 38.215 v17.1.0 From 3GPP TS 38.300 v17.0.0 5.7 SIDELINK 5.7.1 General Sidelink supports UE-to-UE direct communication using the sidelink resource allocation modes, physical-layer signals/channels, and physical layer procedures below. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT 5.7.2 Sidelink resource allocation modes Two sidelink resource allocation modes are supported: mode 1 and mode 2. In mode 1, the sidelink resource allocation is provided by the network. In mode 2, UE decides the SL transmission resources in the resource pool(s). 5.7.3 Physical sidelink channels and signals Physical Sidelink Control Channel (PSCCH) indicates resource and other transmission parameters used by a UE for PSSCH. PSCCH transmission is associated with a DM-RS. Physical Sidelink Shared Channel (PSSCH) transmits the TBs of data themselves, and control information for HARQ procedures and CSI feedback triggers, etc. At least 6 OFDM symbols within a slot are used for PSSCH transmission. PSSCH transmission is associated with a DM-RS and may be associated with a PT- RS. Physical Sidelink Feedback Channel (PSFCH) carries HARQ feedback over the sidelink from a UE which is an intended recipient of a PSSCH transmission to the UE which performed the transmission. PSFCH sequence is transmitted in one PRB repeated over two OFDM symbols near the end of the sidelink resource in a slot. The Sidelink synchronization signal consists of sidelink primary and sidelink secondary synchronization signals (S-PSS, S-SSS), each occupying 2 symbols and 127 subcarriers. Physical Sidelink Broadcast Channel (PSBCH) occupies 9 and 5 symbols for normal and extended CP cases respectively, including the associated DM- RS. 5.7.4 Physical layer procedures for sidelink 5.7.4.1 HARQ feedback Sidelink HARQ feedback uses physical sidelink feedback channel (PSFCH) and can be operated in one of two options. In one option, which can be configured for unicast and groupcast, PSFCH transmits either ACK or NACK using a resource Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT dedicated to a single PSFCH transmitting UE. In another option, which can be configured for groupcast, PSFCH transmits NACK, or no PSFCH signal is transmitted, on a resource that can be shared by multiple PSFCH transmitting UEs. In sidelink resource allocation mode 1, a UE which received PSFCH can report sidelink HARQ feedback to gNB via PUCCH or PUSCH. 5.7.4.2 Power Control For in-coverage operation, the power spectral density of the sidelink transmissions can be adjusted based on the pathloss from the gNB. For unicast, the power spectral density of some sidelink transmissions can be adjusted based on the pathloss between the two communicating UEs. 5.7.4.3 CSI report For unicast, channel state information reference signal (CSI-RS) is supported for CSI measurement and reporting in sidelink. A CSI report is carried in a sidelink MAC CE. 5.7.5 Physical layer measurement definition For measurement on the sidelink, the following UE measurement quantities are supported: - PSBCH reference signal received power (physical sidelink broadcast channel (PSBCH) reference signal received power (RSRP)); - PSSCH reference signal received power (PSSCH-RSRP); - PSСCH reference signal received power (PSCCH-RSRP); - Sidelink received signal strength indicator (SL RSSI); - Sidelink channel occupancy ratio (SL CR); - Sidelink channel busy ratio (SL CBR). From 3GPP TS 36.843 v12.0.1 9.1.2 Resource allocation Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT From a transmitting UE’s perspective, a UE can operate in two modes for resource allocation: - Mode 1: eNodeB or Release-10 relay node schedules the exact resources used by a UE to transmit direct data and direct control information - FFS: if semi-static resource pool restricting the available resources for data and/or control is needed - Mode 2: a UE on its own selects resources from resource pools to transmit direct data and direct control information - FFS if the resource pools for data and control are the same - FFS: if semi-static and/or pre-configured resource pool restricting the available resources for data and/or control is needed - D2D communication capable UE shall support at least Mode 1 for in-coverage - D2D communication capable UE shall support Mode 2 for at least edge-of- coverage and/or out-of-coverage FIGS. 2-4 illustrate examples of a sidelink slot. More specifically, FIG. 2 illustrates a sidelink slot structure 200 with 14 symbols available, FIG. 3 illustrates a sidelink slot structure 300 with 14 symbols available, and FIG.4 illustrates a sidelink slot structure 400 with 13 symbols available. The sidelink slot structure contains automatic gain control (AGC) symbol at the beginning of the slot then PSCCH symbol followed by the PSSCH symbols and the last symbol in the slot is configured as a gap symbol (guard as shown in the FIGS. 2-4) to enable switching time from transmit (Tx) to receive (Rx). Resource pool may be (pre)configured with one or two PSFCH symbol(s), using a PSFCH period of, for example, 1, 2, 4, 8 slots and the slots where the PSFCH occurs maybe configured with additional AGC symbol and a gap symbols as seen from FIGS. 2-4 to enable switching from Tx to Rx for the reception of HARQ feedback. A resource pool (RP) can be shared by several UEs for their SL transmissions. A resource pool consists of contiguous physical resource blocks (PRBs) and contiguous or non-contiguous slots that have been (pre-)configured for sidelink (SL) Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT transmissions. A resource pool must be defined within the SL bandwidth part (BWP) (See FIG.5). FIG.5 illustrates an exemplary resource pool (RP) structure 500. An RP can be used for all transmission types (i.e., unicast, groupcast, and broadcast). A UE can be (pre-)configured with multiple RPs for transmission (transmit RPs) and with multiple RPs for reception (receive RPs). A UE can then receive data on resource pools used for SL transmissions by other UEs, while the UE can still transmit on the SL using its transmit resource pools. In the frequency domain, a resource pool is divided into a (pre-)configured number ^ of contiguous sub-channels, where a sub-channel consists of a group of consecutive PRBs in a slot. The number ^sub of PRBs in a sub-channel corresponds to the sub-channel size, which is (pre-)configured within a resource pool. In NR V2X SL, the sub-channel size ^sub can be equal to 10, 12, 15, 20, 25, 50, 75, or 100 PRBs. A sub-channel represents the smallest unit for a sidelink data transmission or reception. A sidelink transmission can use one or multiple sub-channels. In the time domain, the slots that are part of a resource pool are (pre-)configured and occur with a periodicity of 10240ms. The slots that are part of a resource pool can be (pre- )configured with a bitmap. The length of the bitmap can be equal to 10, 11, 12, …, 160. At each slot of a resource pool, only a subset of consecutive symbols are (pre- )configured for the sidelink , i.e., a subset out of the 14 or 12 symbols per slot for a normal or extended cyclical prefix (CP), respectively. The subset of SL symbols per slot is indicated with a starting symbol and a number of consecutive symbols, where these two parameters are (pre-)configured per resource pool. The number of consecutive SL symbols can vary between 7 and 14 symbols, e.g., depending on the physical channels which are carried within a slot (e.g., see FIGS.2-4). 3GPP TS 37.213 v17.2.0 introduces several definitions and provisions for uplink and downlink unlicensed channel access, however for sidelink the present disclosure provides the following definitions and characteristics. For sidelink, a reference duration corresponding to a channel occupancy initiated by the UE including transmission of PSSCH(s) can be defined as either (1) a duration starting from the beginning of the channel occupancy until the end of the first slot where at Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT least one PSSCH is transmitted, or until the end of the first transmission burst by the UE that contains PSSCH(s), whichever occurs earlier; or (2) the duration of the first transmission burst by the UE within the channel occupancy that contains PSSCH(s). Channel occupancy refers to transmission(s) on channel(s) by eNB/gNB/UE(s) after performing the corresponding channel access procedures in this clause. A sidelink transmission burst is defined as a set of transmissions from a UE without any gaps greater than 16^^. Transmissions from a UE separated by a gap of more than 16^s are considered as separate SL transmission bursts. A UE can transmit transmission(s) after a gap within a SL transmission burst without sensing the corresponding channel(s) for availability. CWS update in case of no HARQ feedback According to an embodiment, if there is no feedback enabled for a transmission, the CW p value, as noted above, is increased to the next higher possible value after a first CW p value has been applied for a first number K noHARQ times. According to an embodiment, if there is no feedback enabled for a transmission, the CW p value is decreased to the lowest possible value after the highest CW p value has been applied for a first number K noHARQ times. ^ According to an implementation, the increase/decrease is applied per priority class p. o According to an implementation, the value K noHARQ is selected by a UE from a set of values. In a specific implementation, the value K noHARQ is selected by the UE from the set of values {1, 2, …, 8}. As a further example, the value K noHARQ could alternatively be selected by the UE from the set of values {1, 2, 3, 4}. Other set values are further possible without departing from the scope of the present application. According to an alternative implementation, the value K noHARQ is determined per resource pool from a set of values. In a specific implementation, the value K noHARQ is determined as one of the values Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT from the set of values {1, 2, …, 8}. Other set values are further possible without departing from the scope of the present application. According to an implementation, the K noHARQ value increases for higher CW p values, or generally the K noHARQ value is different for different CW p values. ^ According to an alternative embodiment, if there is no feedback for a transmissions, the CW p value is selected randomly from the set of allowed values. According to an implementation, a new CW p value is selected after the latest CW p value has been applied for a first number K noHARQ times. o According to an implementation, the value K noHARQ is selected by a UE from a set of values. In a specific implementation, the value K noHARQ is selected by the UE from the set of values {1, 2, …, 8}. As noted above alternative sets of values are possible without departing from the teachings of the present application. According to an alternative implementation, the value K noHARQ is determined per resource pool from a set of values. In a specific implementation, the value K noHARQ is determined as one of the values from the set of values {1, 2, …, 8}. Other set values are further possible without departing from the scope of the present application. According to an implementation, the K noHARQ value increases for higher CW p values, or generally the K noHARQ value is different for different CW p values. CWS update in case of NACK-only feedback ^ According to an embodiment, if there is NACK-only feedback enabled for a transmission, the CW p value is increased to the next higher possible value after a second number K NACKonly of NACK feedback has been received. ^ According to an embodiment, if there is NACK-only feedback enabled for a transmission, the CW p value is decreased to the lowest possible value after the highest CW p value has been applied for a second number K NACKonly times. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT o According to an implementation, the increase/decrease is applied per priority class p. o According to an implementation, the counter of NACK feedback is reset to zero if the CW p value is decreased. o According to an implementation, the value K NACKonly is selected by a UE from a set of values. In a specific implementation, the value K NACKonly is selected by the UE from the set of values {1, 2, …, 8}. According to an alternative implementation, the value K NACKonly is determined per resource pool from a set of values. In a specific implementation, the value K NACKonly is determined as one of the values from the set of values {1, 2, …, 8}. Other set values are further possible without departing from the scope of the present application. According to an implementation, the K NACKonly value increases for higher CW p values, or generally the K NACKonly value is different for different CW p values. ^ According to an alternative embodiment, if there is NACK-only feedback enabled for a transmissions, the CW p value is selected randomly from the set of allowed values (see also section 3.1.3). According to an implementation, a new CW p value is selected after the latest CW p value has been applied for a first number K NACKonly times. o According to an implementation, the value K noHARQ is selected by a UE from a set of values. In a specific implementation, the value K NACKonly is selected by the UE from the set of values {1, 2, …, 8}. According to an alternative implementation, the value K NACKonly is determined per resource pool from a set of values. In a specific implementation, the value K NACKonly is determined as one of the values from the set of values {1, 2, …, 8}. Other set values are further possible without departing from the scope of the present application. According to an implementation, the K noHARQ value increases for higher CW p values, or generally the K NACKonly value is different for different CW p values. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT Allowed ^ ^^ sizes The number of values in the allowed contention window sizes for sidelink channel access may be limited (e.g. such as for priority class 3,4) compared to unicast. TS 37.213 defines the following channel access priority classes and corresponding parameters for DL and UL channel access, respectively: According to the embodiment, for channel access in sidelink, a subset of the values "allowed ^ ^^ sizes" from these tables can be used for sidelink channel access. For example, instead of the set {15,31,63,127,255,511,1023} as for channel access priority class 3 and 4 in UL channel access, the set {15,31,63,127} can be used for SL channel access, though the values do not have to be consecutive with respect to the existing set, so that an alternative set could be {15,63,255,1023}. This could be Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT beneficial in the "no HARQ feedback" case where the CWS is increased automatically, so that extremely large values might be avoided. CWS update based on channel busy ratio (CBR) According to an embodiment, the CW p value is selected as a function of the CBR. In an implementation the UE selects one out of the allowed ^ ^^ sizes for sidelink channel access depending on the CBR. For example ^ if the CBR is below a first threshold, the UE selects the smallest allowed ^ ^^ size for sidelink channel access. o For example when using the set {15,31,63,127,255,511,1023} for the allowed ^ ^^ sizes, this means selecting the value 15. ^ if the CBR is above a first threshold and below a second threshold, the UE selects the second but smallest allowed ^ ^^ size for sidelink channel access. o For example when using the set {15,31,63,127,255,511,1023} for the allowed ^ ^^ sizes, this means selecting the value 31. ^ etc… ^ if the CBR is above a third threshold the UE selects the second but largest allowed ^ ^^ size for sidelink channel access. o For example when using the set {15,31,63,127,255,511,1023} for the allowed ^ ^^ sizes, this means selecting the value 1023. ^ Each of the first/second/third etc. threshold values can be predefined, e.g. configurable by the network. For example the configuration may be UE- specific or resource pool specific. This can be beneficial in the "no HARQ feedback" case because it allows a differentiation of contention window sizes as a function of an available measurement. The thresholds and mapping to ^ ^^ values can be priority class specific, i.e. a first threshold applicable for priority class p=1 resulting in the lowest ^ ^^ for p=1 being chosen is a different threshold than applicable for pririty class p=2 resulting in the lowest ^ ^^ for p=2 being chosen. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT According to an implementation, the thresholds constitute a plurality of CBR ranges. The first CBR range is between 0 and the first threshold, the second CBR range is between the first threshold and the second threshold, and so forth (where it is a matter of choice whether the threshold value itself belongs to the lower or higher range). Then each such range can be associated with a ^ ^^ size from a set of allowed ^ ^^ sizes. The corresponding relations between CBR range and ^ ^^ size can be represented by a lookup table, which may be preconfigured by the network such as by RRC. Furthermore the corresponding relations between CBR range and ^ ^^ size can be specific to a resource pool. As presently described, several possible embodiments have been discussed. At least a couple of examples of discussed possible embodiments include: increasing CWS only after a configurable number of NACKs; increasing CWS after a configurable number of transmissions; decreasing CWS after no feedback if NACK-only is configured; and decreasing CWS after no feedback for a configurable number of transmssions if NACK-only is configured. Such a list only represents a partial list of the possible embodiments, as noted above. FIG. 6 illustrates a flow diagram 600 of a method in a user equipment. The method includes selecting 602 one of an ordered sequence of values corresponding to a plurality of values for use as a maximum contention window size for an associated priority class for use by the user equipment in determining a contention window size to be used in identifying whether a channel in the unlicensed carrier is clear by a transmission authorization procedure. The user equipment is authorized to make use of the channel for a sidelink transmission after the user equipment uses the determined contention window size, based on the selected value for the maximum contention window size, to identify that the channel in the unlicensed carrier is clear for a number of sensing slots in accordance with the determined contention window Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT size 604. For subsequent sidelink transmission authorization procedure(s), a determination is made as to whether the maximum contention window size is updated from which a new current contention window size can be determined for use in identifying whether the channel in the unlicensed carrier to be used for the subsequent sidelink transmissions is clear 606. While a transmission authorization procedure is specifically noted, it is possible that this could alternatively be referenced as a channel access procedure. It is further noted that for purposes of identifying an unlicensed carrier that is clear, it is possible that the contention window could be satisfied by identifying an appropriate number of idle slots that may not be consecutive. For example if the determined CWS is 2 sensing slots, the first idle slot can be at time t1 (reducing the counter to 1), then the channel can be busy for a period of time including a period of time that is potentially a long time, and then at a later time t2 the channel could be sensed as idle again (reducing the counter to 0), so that after the two sensing slots that were identified as being idle are detected, that the UE is allowed to access the channel. Further still, when an update to the contention window size is identified as being desired, in at least some instances, the update could be delayed until a further transmission that is not in the same channel occupancy, which could correspond to the next time that the channel occupancy engine for performing the authorization checking routine is performed. In some instances, the sidelink communication can have an associated type of feedback, wherein, when the associated type of feedback is a no HARQ feedback, the maximum contention window size can be updated after a configured number of transmission authorization procedures using a particular selected one of the ordered sequence of values corresponding to a particular maximum contention window size. The number of transmissions could correspond to a number of slots that have transmissions. Still further, it could alternatively correspond to a number of times that the channel access procedure for one or more transmissions is executed. In some instances, after the configured number of transmission authorization procedures using the particular selected one of the ordered sequence of values have Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT occurred, a next one of the ordered sequence of values corresponding to a next higher value for use as a maximum contention window size can be selected. When there is no next higher value in the plurality of values for use as the maximum contention window size for the associated priority class, the next one of the ordered sequence of values corresponding to the lowest possible value for use as a maximum contention window size in the ordered sequence of values can be selected. In other instances, a transmission authorization procedure can be associated with a particular one of a plurality of possible priority classes, wherein the configured number of transmission authorization procedures used for determining when to update the maximum contention window size associated with the particular one of the plurality of possible priority classes can be dependent on the configured number of transmission authorization procedures associated with the particular priority class. In some of these instances, the configured number of transmission authorization procedures for each one of the plurality of possible priority classes, which triggers an update in the associated maximum contention window size can be separately defined. In other of these instances, the configured number of transmission authorization procedures for each one of the plurality of possible priority classes, can be based upon the number of associated values for use as a maximum contention window size in the ordered sequence of values, which are associated with the particular priority class. In some instances, after the configured number of transmission authorization procedures using the particular selected one of the ordered sequence of values, a next one of the ordered sequence of values can be randomly selected from the ordered sequence of values for use as the maximum contention window size for the associated priority class. In instances, where the values within the set are selected randomly, it may be possible that the sequence of values could include a sequence of values that does not follow in a lowest-to-highest or highest-to-lowest ordering. In some instances the sidelink communication has an associated type of feedback, wherein, when the associated type of feedback is a NACK-only feedback or Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT an ACK/NACK feedback, the maximum contention window size can be updated after a configured number of NACK feedback for sidelink transmissions within a reference duration has been received, where the reference duration includes sidelink transmission(s) from the beginning of a channel occupancy. In some of these instances, after the configured number of NACK feedback has been received, a next one of the ordered sequence of values corresponding to a next higher value for use as a maximum contention window size is selected. When there is no next higher value in the plurality of values for use as the maximum contention window size for the associated priority class, the next one of the ordered sequence of values corresponding to the lowest possible value for use as a maximum contention window size in the ordered sequence of values can be selected. In other of these instances, each transmission authorization procedure can be associated with a particular one of a plurality of possible priority classes, wherein the configured number of transmission authorization procedures used for determining when to update the maximum contention window size associated with the particular one of the plurality of possible priority classes can be dependent on the configured number of transmission authorization procedure associated with the particular priority class. In still other of these instances, a count associated with a tracking of the number of NACK feedback that has been received can be reset to zero after the maximum contention window size has been updated. Further yet in other of these instances, each transmission authorization procedure can be associated with a particular one of a plurality of possible resource pools, where each resource pool corresponds to a different subset of a plurality of resources associated with the unlicensed carrier, wherein the configured number of transmission authorization procedures used for determining when to update the maximum contention window size associated with the particular one of the plurality of possible resource pools can be dependent on the configured number of transmission authorization procedure associated with the particular resource pool having been transmitted. Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT In some instances, each of the sidelink transmissions can have a corresponding type of transmission from a list including unicast, groupcast or broadcast, wherein for a transmission authorization procedure for a channel occupancy including at least some of the types of transmission, the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size can be truncated to a number less than all of the values for one or more of a particular associated priority class. In some instances, each of the sidelink transmissions can have a corresponding type of transmission from a list including unicast, groupcast or broadcast, wherein for a transmission authorization procedure for a channel occupancy including at least some of the types of transmission, the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size can be a subset corresponding to a number less than all of the values for one or more of a particular associated priority class. In some instances, when selecting one of an ordered sequence of values corresponding to a plurality of values for use as a maximum contention window size for an associated priority class, a channel busy ratio can be determined, wherein the channel busy ratio can be compared to one or more thresholds, where depending upon the outcome of the comparisons of the channel busy ratio to the one or more thresholds will determine which one of the ordered sequence of values corresponding to the plurality of values for use as the maximum contention window size for the associated priority class is selected. In some of these instances, a number of thresholds against which the channel busy ratio is compared can be one less than a number of values in the ordered sequence of values for the associated priority class. It should be understood that, notwithstanding the particular steps as shown in the figures, a variety of additional or different steps can be performed depending upon the embodiment, and one or more of the particular steps can be rearranged, repeated or eliminated entirely depending upon the embodiment. Also, some of the steps performed can be repeated on an ongoing or continuous basis simultaneously while Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT other steps are performed. Furthermore, different steps can be performed by different elements or in a single element of the disclosed embodiments. FIG.7 is an example block diagram of an apparatus 700, such as the wireless communication device 110, according to a possible embodiment. The apparatus 700 can include a housing 710, a controller 720 within the housing 710, audio input and output circuitry 730 coupled to the controller 720, a display 740 coupled to the controller 720, a transceiver 750 coupled to the controller 720, an antenna 755 coupled to the transceiver 750, a user interface 760 coupled to the controller 720, a memory 770 coupled to the controller 720, and a network interface 780 coupled to the controller 720. The apparatus 700 can perform the methods described in all the embodiments. The display 740 can be a viewfinder, a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display, a projection display, a touch screen, or any other device that displays information. The transceiver 750 can include a transmitter and/or a receiver. The audio input and output circuitry 730 can include a microphone, a speaker, a transducer, or any other audio input and output circuitry. The user interface 760 can include a keypad, a keyboard, buttons, a touch pad, a joystick, a touch screen display, another additional display, or any other device useful for providing an interface between a user and an electronic device. The network interface 780 can be a Universal Serial Bus (USB) port, an Ethernet port, an infrared transmitter/receiver, an IEEE 1394 port, a WLAN transceiver, or any other interface that can connect an apparatus to a network, device, or computer and that can transmit and receive data communication signals. The memory 770 can include a random access memory, a read only memory, an optical memory, a solid state memory, a flash memory, a removable memory, a hard drive, a cache, or any other memory that can be coupled to an apparatus. The apparatus 700 or the controller 720 may implement any operating system, such as Microsoft Windows®, UNIX®, or LINUX®, Android TM , or any other operating system. Apparatus operation software may be written in any programming language, such as C, C++, Java or Visual Basic, for example. Apparatus software may also run on an application framework, such as, for example, a Java® framework, Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT a .NET® framework, or any other application framework. The software and/or the operating system may be stored in the memory 770 or elsewhere on the apparatus 700. The apparatus 700 or the controller 720 may also use hardware to implement disclosed operations. For example, the controller 720 may be any programmable processor. Disclosed embodiments may also be implemented on a general-purpose or a special purpose computer, a programmed microprocessor or microcontroller, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, hardware/electronic logic circuits, such as a discrete element circuit, a programmable logic device, such as a programmable logic array, field programmable gate-array, or the like. In general, the controller 720 may be any controller or processor device or devices capable of operating an apparatus and implementing the disclosed embodiments. Some or all of the additional elements of the apparatus 700 can also perform some or all of the operations of the disclosed embodiments. The method of this disclosure can be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this disclosure. While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as Golitschek Edler von Elbwart et al. Attorney Docket No.: SMM920220106-WO-PCT set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. In this document, relational terms such as "first," "second," and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The phrase "at least one of," "at least one selected from the group of," or "at least one selected from" followed by a list is defined to mean one, some, or all, but not necessarily all of, the elements in the list. The terms "comprises," "comprising," "including," or any other variation thereof, are intended to cover a non- exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a," "an," or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Also, the term "another" is defined as at least a second or more. The terms "including," "having," and the like, as used herein, are defined as "comprising." Furthermore, the background section is written as the inventor's own understanding of the context of some embodiments at the time of filing and includes the inventor's own recognition of any problems with existing technologies and/or problems experienced in the inventor's own work.