Slot structure and start symbol for unlicensed spectrum sidelink operation

Abstract

A user equipment (UE) is configured to receive configuration information for a sidelink connection in an unlicensed frequency band, the configuration information comprising a first candidate start symbol position for a time slot, where the time slot comprises a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) transmission; and determining a second candidate start symbol position for the time slot based at least on the first candidate start symbol position.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and in particular, to slot structures and starting symbols for unlicensed spectrum sidelink operations. Background Art

[0002] Several areas of user equipment (UE) sidelink behavior in unlicensed spectrum remain undefined. Specifically, a slot structure capable of supporting two start symbols in a slot remains an open question. Additionally, the UE requires a defined procedure for transmitting the sidelink-synchronization signal block (S-SSB). Summary of the Invention

[0003] Some exemplary embodiments relate to a method performed by a user equipment (UE), the method comprising: receiving configuration information for a sidelink connection in an unlicensed band, the configuration information comprising a first candidate starting symbol position for a time slot, wherein the time slot comprises a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) transmission; and determining a second candidate starting symbol position for the time slot based at least on the first candidate starting symbol position.

[0004] Other exemplary embodiments relate to a method performed by a user equipment (UE), the method comprising: receiving a first physical sidelink control channel (PSCCH) symbol in a time slot of a sidelink transmission in an unlicensed band; blind decoding the PSCCH symbol, wherein the blind decoding is successful; determining a condition; and skipping a blind decoding operation for a second PSCCH symbol in the time slot.

[0005] Other exemplary embodiments relate to a method performed by a first user equipment (UE), the method comprising: receiving configuration information for a sidelink connection in an unlicensed band, the configuration information comprising one or more primary sidelink-synchronization signal block (S-SSB) opportunities and one or more secondary S-SSB opportunities, wherein each primary S-SSB opportunity corresponds to a predetermined number of secondary S-SSB opportunities; and determining whether the UE is allowed to transmit an S-SSB to a second UE at the primary S-SSB opportunity. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Exemplary network arrangements are shown according to various exemplary embodiments.

[0007] Figure 2 An exemplary UE according to various exemplary embodiments is shown.

[0008] Figure 3 An exemplary base station is shown in accordance with various exemplary embodiments.

[0009] Figure 4 A flow chart for determining a location of a second candidate starting symbol for sidelink operation is shown according to various exemplary embodiments.

[0010] Figure 5A A diagram indicating AGC symbols for a sidelink resource pool containing more than one set of resource blocks (RBs) is shown according to various exemplary embodiments.

[0011] Figure 5B A diagram of a sidelink resource pool for having simultaneous transmissions on different bandwidths is shown, according to various exemplary embodiments.

[0012] Figure 6 An Unlicensed S-SSB timing diagram is shown according to various exemplary embodiments.

[0013] Figure 7 A flow chart for transmitting S-SSB in an unlicensed spectrum is shown, according to various exemplary embodiments.

[0014] Figure 8 A second unlicensed S-SSB timing diagram is shown in accordance with various exemplary embodiments.

[0015] Figure 9 A second flow chart for transmitting S-SSB in unlicensed spectrum is shown. DETAILED DESCRIPTION

[0016] The exemplary embodiments may be further understood with reference to the following description and associated drawings, wherein like elements are provided with like reference numerals.The exemplary embodiments are directed to improvements to UE sidelink operations in unlicensed spectrum.

[0017] The exemplary embodiments are described with reference to a UE. However, reference to a UE is provided for illustrative purposes only. The exemplary embodiments may be utilized with any electronic component that can establish a connection with an accessory device and is configured with hardware, software, and / or firmware for exchanging information and data with the accessory device. Therefore, the term UE as described herein is used to represent any electronic component.

[0018] The exemplary embodiments are also described with reference to 5G New Radio (NR) networks. However, it should be understood that the exemplary embodiments may also be implemented in other types of networks, including but not limited to LTE networks, future evolutions of cellular protocols (e.g., 6G networks), or any other type of network.

[0019] Example embodiments are also described with reference to sidelink connections. Sidelink connections can generally be understood as transmissions between UEs (e.g., phones, tablets, smartwatches, connected vehicles, etc.) without the need for a base station to transmit or receive data. Sidelink operation may be desirable in scenarios where ultra-low latency transmissions between connected devices (e.g., connected vehicles) are required.

[0020] Many areas of NR sidelink operation in unlicensed spectrum require further definition. As used herein, unlicensed spectrum may include, but is not limited to, spectrum (e.g., frequency band) where spectrum access is contention-based. Two such areas are defining a slot structure to support two start symbols in a slot and defining a procedure for UEs to transmit S-SSBs. Example embodiments address these two areas of undefined UE unlicensed sidelink operation.

[0021] Figure 1 An exemplary network arrangement 100 according to various exemplary embodiments is shown. The exemplary network arrangement 100 includes a UE 110 and a UE 115. Those skilled in the art will appreciate that the UEs 110 and 115 can be any type of electronic components configured to communicate via a network, such as mobile phones, tablet computers, desktop computers, smartphones, phablets, embedded devices, wearable devices, Internet of Things (IoT) devices, and the like. It should also be understood that an actual network arrangement can include any number of UEs used by any number of users. Therefore, the example with two UEs 110 and 115 is provided for illustrative purposes only. Further description will relate to the UE 110, but it should be understood that all descriptions of the UE 110 apply to the UE 115 throughout this disclosure.

[0022] UE 110 can be configured to communicate with one or more networks. In the example of network configuration 100, the network with which UE 110 can wirelessly communicate is a 5G NR radio access network (RAN) 120. However, it should be understood that UE 110 can also communicate with other types of networks (e.g., 5G cloud RAN, next generation RAN (NG-RAN), traditional cellular networks, etc.), and UE 110 can also communicate with the network via a wired connection. Regarding the exemplary embodiment, UE 110 can establish a connection with 5G NR RAN 120. Therefore, UE 110 can have a 5G NR chipset to communicate with NR RAN 120. UE 110 can also communicate with UE 115 via an unlicensed sidelink connection, where data is exchanged between UE 110 and UE 115 without gNB 120A.

[0023] The 5G NR RAN 120 may be part of a cellular network that may be deployed by a network operator (e.g., Verizon, AT&T, T-Mobile, etc.). The RAN 120 may include cells or base stations that are configured to send and receive traffic from UEs equipped with appropriate cellular chipsets. In this example, the 5G NR RAN 120 includes a gNB 120A. However, reference to a gNB is provided for illustrative purposes only, and any suitable base station or cell (e.g., a Node B, eNodeB, HeNB, eNB, gNB, gNodeB, macrocell, microcell, small cell, femtocell, etc.) may be deployed.

[0024] Those skilled in the art will appreciate that any relevant procedures may be performed for UE 110 to connect to 5G NR RAN 120. For example, as discussed above, 5G NR RAN 120 may be associated with a particular network operator, where UE 110 and / or its user has protocol and credential information (e.g., stored on a SIM card). Upon detecting the presence of 5G NR RAN 120, UE 110 may transmit corresponding credential information in order to associate with 5G NR RAN 120. More specifically, UE 110 may be associated with a particular cell (e.g., gNB 120A).

[0025] The network arrangement 100 also includes a cellular core network 130, the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network service backbone 160. The cellular core network 130 manages traffic flowing between the cellular network and the Internet 140. The IMS 150 can generally be described as an architecture for delivering multimedia services to the UE 110 using IP protocols. The IMS 150 can communicate with the cellular core network 130 and the Internet 140 to provide multimedia services to the UE 110. The network service backbone 160 communicates directly or indirectly with the Internet 140 and the cellular core network 130. The network service backbone 160 can generally be described as a collection of components (e.g., servers, network storage arrangements, etc.) that implement a set of services that can be used to extend the functionality of the UE 110 to communicate with various networks.

[0026] Figure 2 An exemplary UE 110 is shown according to various exemplary embodiments. The UE 110 will refer to Figure 1100. UE 110 may represent any electronic device and may include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. Other components 230 may include, for example, an audio input device, an audio output device, a battery providing a limited power source, a data acquisition device, a port for electrically connecting UE 110 to other electronic devices, sensors for detecting conditions of UE 110, and the like.

[0027] Processor 205 may be configured to execute multiple engines for UE 110. For example, these engines may include an unlicensed side link engine 235 for performing operations such as generating a slot structure capable of supporting two start symbols in a slot and transmitting S-SSB in unlicensed spectrum.

[0028] The engines described above as applications (e.g., programs) executed by the processor 205 are merely exemplary. The functionality associated with these engines may also be represented as separate integrated components of the UE 110, or may be modular components coupled to the UE 110, such as integrated circuits with or without firmware. For example, the integrated circuit may include input circuits for receiving signals and processing circuits for processing signals and other information. These engines may also be embodied as one application or multiple separate applications. In addition, in some UEs, the functionality described for the processor 205 is split between two or more processors (such as a baseband processor and an application processor). The exemplary embodiments may be implemented in any of these or other configurations of the UE.

[0029] The memory arrangement 210 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 may be a hardware component configured to display data to a user, and the I / O device 220 may be a hardware component that enables a user to enter input. The display device 215 and the I / O device 220 may be separate components or may be integrated together (such as a touch screen). The transceiver 225 may be a hardware component configured to establish a connection with the 5G-NR RAN 120. Thus, the transceiver 225 may operate on a variety of different frequencies or channels (e.g., a set of contiguous frequencies).

[0030] Figure 3 An exemplary base station 300 is shown in accordance with various exemplary embodiments. Base station 300 may represent gNB 120A or any other access node that UE 110 may use to establish a connection and manage network operations.

[0031] The base station 300 may include a processor 305, a memory arrangement 310, input / output (I / O) devices 315, a transceiver 320, and other components 325. These other components 325 may include, for example, an audio input device, an audio output device, a battery, a data acquisition device, ports for electrically connecting the base station 300 to other electronic devices and / or a power source, and the like.

[0032] Processor 305 may be configured to execute multiple engines of UE 110. For example, these engines may include an unlicensed side link engine 330 for performing operations such as generating S-SSBs, AGC symbols, and (pre-)configuration of other sidelink parameters.

[0033] The memory 310 may be a hardware component configured to store data related to operations performed by the base station 300. The I / O device 315 may be a hardware component or port that enables a user to interact with the base station 300. The transceiver 320 may be a hardware component configured to exchange data with the UE 110 and any other UE in the network arrangement 100. The transceiver 320 may operate on a variety of different frequencies or channels (e.g., a set of contiguous frequencies). Thus, the transceiver 320 may include one or more components (e.g., radios) to enable data exchange with various networks and UEs.

[0034] In a first aspect of the exemplary embodiments, a slot structure for supporting two start symbols within a slot is disclosed. Variants of this aspect relate to the position of the second candidate start symbol, the symbol structure for automatic gain control purposes, and UE transmission monitoring of the physical sidelink control channel.

[0035] In a first variation of the first aspect, the position of the second candidate start symbol depends on the position of the first candidate start symbol. A general description of this behavior can be illustrated by example. Consider an exemplary time slot comprising 14 symbols indexed from 0…13. If the position of the first candidate start symbol is at X, where 0≤X≤13, then the position of the second start symbol Y can be determined.

[0036] In a first alternative of the first variant, the position Y of the start symbol can be determined by the following equation: Y=X+ceil((13-X) / 2)), where ceil is a ceiling function of real numbers. As an example, using the equation of the first alternative, if X=2, then Y=8.

[0037] In a second alternative of the first variant, the position Y of the start symbol can be determined by the following equation: Y=X+floor((13-X) / 2)), where floor is the floor function of real numbers. As an example, using the equation of the second alternative, if X=2, then Y=7.

[0038] Those skilled in the art will recognize that the above equations are merely exemplary and that other possible equations and bounds for the independent variable X (ie, the first candidate starting symbol position) are possible.

[0039] The result from the above alternative equation for determining the second candidate starting symbol position may include an upper bound (e.g., the latest possible position of the second candidate starting symbol). For example, in the example provided above, the upper bound may be defined as Y ≤ 8 for the latest possible position of the second candidate starting symbol. If the value of Y calculated according to any of the above alternative equations is higher than the upper bound, there are two options. In the first option, Y may be taken as the upper bound (e.g., if Y exceeds the upper bound, Y may alternatively be defined as the upper bound). In the second option, it may be determined / declared that the time slot does not support the starting candidate symbol.

[0040] The value of X may be (pre)configured, for example, equal to the parameter sl-StartSymbol in the sidelink bandwidth part (BWP) (pre)configuration.

[0041] Figure 4 A flow chart for determining a location of a second candidate starting symbol for sidelink operation is shown according to various exemplary embodiments. Figure 4 Corresponding to the first aspect of the exemplary embodiment.

[0042] In 405, a UE (e.g., UE 110) receives a sidelink bandwidth portion (pre-)configuration on a first candidate start symbol of a time slot. The UE may receive this BWP configuration from gNB 120A or from a locally recovered pre-configuration.

[0043] In 410, UE 110 determines the location of the second candidate starting symbol based on the location of the first candidate starting symbol. Operation 410 may utilize the equation mentioned above to determine the location of the second candidate starting symbol, but other relationships or equations that define the location of the second symbol based on the first symbol are possible.

[0044] In a second variation of the first aspect of the exemplary embodiment, symbols that can be used for automatic gain control (AGC) purposes are defined. AGC is used for dynamic adjustment of gain to reduce interference with unwanted received signals. The second variation of the embodiment can be understood to be applicable to different scenarios, in which the physical side link control channel (PSCCH) / physical side link shared channel (PSSCH) transmission has one or two symbols for AGC purposes, depending on various conditions. In the exemplary embodiment, it is assumed that the PSCCH / PSSCH transmission starts from the first starting symbol. However, this is not a requirement of the exemplary embodiment.

[0045] In a first option of the second variant, the determination of the symbols used for AGC is defined in a semi-static manner based on the number of resource block (RB) sets in the resource pool. If the resource pool contains only a single RB set, the PSCCH and / or PSSCH transmission may have one symbol used for AGC purposes, e.g., the first starting symbol.

[0046] Those skilled in the art will recognize that UEs operating in unlicensed spectrum in the same resource pool perform listen-before-talk (LBT) before transmitting. That is, if a first UE is currently transmitting in a given resource pool, unrelated UEs will not transmit due to the shared resource pool and LBT operation. In the absence of simultaneous transmissions on the resource pool, there is no need to transmit a second AGC symbol.

[0047] On the other hand, if the resource pool includes more than one RB set, the PSCCH / PSSCH transmission may have two symbols for AGC purposes.

[0048] Figure 5A A diagram illustrating an indication of an AGC symbol for a sidelink resource pool containing more than one resource block (RB) set according to various exemplary embodiments is shown. It should be understood that Figure 5A An example is illustrated of a resource pool comprising more than one RB set according to the first option of the second variant, resulting in the presence of two symbols for AGC purposes.

[0049] Figure 5A UE 1, UE 2, UE 3, and UE 4 are shown. UE 1 and UE 3 have an ongoing sidelink connection 530 (specifically, UE 1 transmits to UE 3). UE 2 and UE 4 have an ongoing sidelink connection 525 (specifically, UE 2 transmits to UE 4). Any of UE 1 to UE 4 should be understood to be similar to the above description of the sidelink connection. Figure 2 UE 110 described.

[0050] In this example, the resource pool includes RB set 1 505 and RB set 2 510. In RB set 2 510, UE1 is transmitting to UE3 as part of an ongoing sidelink transmission 530. Additionally, in RB set 1 505, UE2 is transmitting to UE4 as part of an ongoing sidelink transmission 525. Figure 5AAs shown, some symbols of transmission 525 in RB set 1 505 overlap with symbols of transmission 530 in RB set 2 510. It is possible that transmission 525 between UE2 and UE4 may cause overflow in transmission 530 between UE1 and UE3 (e.g., the close proximity in frequency between the symbols may cause UE3 to receive a portion of the information being transmitted in transmission 525).

[0051] Usually, the first symbol of a time slot is an AGC symbol. Figure 5A 505 to 530 on RB set 2 510. This is depicted by AGC symbol 515 of transmission 530 in FIG. However, as described above, in the first option of the second variant, a second symbol may also be used for AGC purposes to compensate for potential overflow of transmission 525 on RB set 1 505 into transmission 530 on RB set 2 510. This additional AGC symbol 520, which is aligned in time with the first symbol of transmission 525, assists UE 3 in compensating for any overflow of transmission 525. The second AGC symbol may also be repeated in future time slots (not shown).

[0052] In a second option of the second variant, the determination of the symbols used for AGC is also defined in a semi-static manner.In this option, the resource pool may be (pre-)configured as to whether a PSCCH / PSSCH transmission has one or two symbols used for AGC purposes.

[0053] For example, if a resource pool contains only a single RB set, the resource pool may be (pre)configured such that the PSCCH / PSSCH transmission includes one symbol for AGC purposes. If a resource pool contains more than one RB set, the resource pool may be (pre)configured such that the PSCCH / PSSCH transmission includes one or two symbols for AGC purposes.

[0054] In another example, if the resource pool contains only a single RB set, the resource pool always has 1 symbol used for AGC purposes. If the resource pool contains more than one RB set, the resource pool can be (pre-)configured such that the PSCCH / PSSCH transmission includes one or two symbols for AGC purposes.

[0055] In a third option of the second variant, the determination of the symbols used for AGC is dynamically defined based on the bandwidth of the PSCCH / PSSCH transmission. Specifically, if a PSCCH / PSSCH transmission occupies the full bandwidth of the resource pool, the PSCCH / PSSCH transmission may have one symbol used for AGC purposes. This is because if an unrelated UE detects that the UE is currently transmitting across the entire bandwidth of the resource pool (e.g., the entire resource pool is occupied), the unrelated UE will perform an LBT procedure and not transmit.

[0056] On the other hand, if the PSCCH / PSSCH transmission occupies only part of the bandwidth of the resource pool, the PSCCH / PSSCH transmission may have two symbols for AGC purposes. Figure 5A The operations described are different, and the diagram applies to two separate resource pools.

[0057] Figure 5B A diagram of a sidelink resource pool for simultaneous transmissions on different bandwidths according to various exemplary embodiments is shown. Figure 5A In comparison, Figure 5B In FIG, resource pool 535 includes only a single RB set, eg, the RB set spans the entire resource pool 535 .

[0058] Figure 5B UE 1, UE 2, UE 3, and UE 4 are shown. UE 1 and UE 3 have an ongoing sidelink connection 545 (specifically, where UE 1 transmits to UE 3). UE 2 and UE 4 have an ongoing sidelink connection 540 (specifically, where UE 2 transmits to UE 4). Again, any of UE 1 through UE 4 should be understood to be similar to the above description regarding Figure 2 UE 110 is described.

[0059] In this example, UE1 is transmitting to UE3 as part of an ongoing sidelink transmission 545 in resource pool 535. However, it can be assumed that transmission 545 does not occupy the entire bandwidth of resource pool 535. Therefore, this also allows UE2 to transmit to UE4 as part of an ongoing sidelink transmission 540 in the portion of the bandwidth of resource pool 535 not occupied by transmission 545. Figure 5B As shown, some symbols of transmission 540 overlap with symbols of transmission 545. Thus, according to a third option of the second variation, transmission 545 may have two symbols (AGC 550 and AGC 55) used for AGC purposes. AGC symbol 550 is the first starting symbol, and AGC symbol 555 is aligned in time with the first symbol of transmission 540.

[0060] In a third variation of the first aspect of the exemplary embodiment, receiver UE monitoring operations for the PSCCH are disclosed. If a sidelink receiving UE successfully decodes the PSCCH corresponding to the first candidate start symbol in a slot (i.e., before the second candidate start symbol), several conditions may cause the receiving UE to not perform further PSCCH blind decoding operations. Any of the following conditions, alone or in combination, may cause the receiving UE to not perform further PSCCH blind decoding operations.

[0061] The first condition is whether the PSSCH transmission corresponding to the decoded PSCCH is a full-bandwidth transmission across the entire resource pool. In this case, the receiving UE is guaranteed that the decoded PSCCH corresponds to any transmission that the receiving UE wants to receive, because when the PSSCH transmission occupies the entire bandwidth of the resource pool, there may be no other PSCCH transmissions within the resource pool.

[0062] The second condition is that the resource pool includes only a single RB set. Similar to the above condition, when this condition occurs, the receiving UE is ensured that there are no other transmissions in the resource pool destined for the receiving UE.

[0063] The third condition is whether the receiving UE has reached the maximum number of blind decoding attempts. In this case, the receiving UE has reached the maximum limit of its decoding attempts and will not attempt any further decoding of the PSCCH.

[0064] In a second aspect of the exemplary embodiment, operations related to the UE side link-synchronization signal block (S-SSB) process are disclosed. Those skilled in the art will understand that in the licensed band, the S-SSB is transmitted on a periodic basis. For example, Rel-16 and Rel-17 define such a period as 160ms. It is conceivable that in future releases, the S-SSB will be able to be transmitted periodically in the unlicensed band. It is possible that the unlicensed S-SSB can be transmitted with a period similar to or the same as the period of the licensed S-SSB transmission (i.e., 160ms). However, the exemplary embodiment is not limited to this period, but is applicable to any period defined for the unlicensed band.

[0065] It should be understood that any reference to Rel-16 and Rel-17 in the following portions of this disclosure refers to unlicensed S-SSB transmissions having a transmission period equivalent to an S-SSB transmission in the licensed portion of the spectrum. The use of licensed periodicity and 160 ms is exemplary only. Those skilled in the art will recognize that the unlicensed period can be any desired value and that the unlicensed periodicity need not have any relationship to the periodicity of licensed S-SSB transmissions. It should also be understood that reference to a "primary" S-SSB or S-SSB opportunity can refer to both Rel-16 and Rel-17 transmission intervals, but need not exclusively refer to both Rel-16 and Rel-17 transmission intervals. "Primary" S-SSB or S-SSB opportunity is used in this disclosure to refer to an S-SSB / S-SSB opportunity at which an additional (i.e., non-primary) S-SSB to be transmitted at the additional S-SSB opportunity may first occur (and fail).

[0066] Transmission of additional candidate S-SSB opportunities may be useful in unlicensed spectrum where a UE is competing with other nearby UEs for time and frequency resources to transmit. The increased transmission density of unlicensed spectrum invariably results in transmission collisions, resulting in S-SSBs not being received by the intended UE. Therefore, transmission of additional candidate S-SSBs will alleviate issues associated with S-SSB transmission in unlicensed spectrum.

[0067] Figure 6 FIG2 shows an unlicensed S-SSB timing diagram according to various exemplary embodiments. Notably, the Rel-16 and Rel-17 S-SSB opportunities 605 occur with a 160ms periodicity (in this case, with two S-SSB opportunities). Again, it should be emphasized that the 160ms periodicity and two Rel-16 and Rel-17 S-SSB 605 opportunities per period are exemplary only.

[0068] exist Figure 6 Of further note in FIG6 is the additional candidate S-SSB opportunity represented by the cross-hatched box 610. Adding the additional candidate S-SSB opportunity increases the likelihood of successfully transmitting an S-SSB on the crowded unlicensed spectrum.

[0069] There are two main scenarios that are possible when adding additional candidate S-SSB opportunities 610. In the first scenario, each Rel-16 / Rel-17 sidelink S-SSB slot has K corresponding additional S-SSB opportunities, and the gaps between S-SSB opportunities are (pre)configured. Figure 6 In this example, each Rel-16 / Rel-17 side link S-SSB slot 605 has K=2 additional S-SSB opportunities (i.e., two cross-hatched boxes after each empty box). The gap between each of the S-SSB opportunities (e.g., the gap between the first Rel-16 / Rel-17 side link S-SSB slot 605 and the first additional S-SSB opportunity 610 and the gap between the first additional S-SSB opportunity 610 and the second additional S-SSB opportunity) can be (pre-)configured, for example, 40ms, 50ms, 60ms, etc.

[0070] The second scenario may be when the number of candidate S-SSB opportunities is (pre)configured and the position is determined based on the (pre)configured number. For example, the number of S-SSB opportunities may be divided by the period and distributed within the period.

[0071] Figure 7Flowcharts for transmitting S-SSB in unlicensed spectrum according to various exemplary embodiments are shown. Again, it should be understood that the Rel-16 / Rel-17 S-SSB timings refer to periodic transmission intervals that are merely exemplary and based on conventional periodic transmission intervals for S-SSB in licensed spectrum (e.g., Figure 6 Other S-SSB opportunity intervals are possible, and the examples of Rel-16 / Rel-17 S-SSB opportunities are exemplary only.

[0072] In 705, a UE (e.g., UE 110) receives a sidelink BWP (pre)configuration for a Rel-16 / Rel-17 S-SSB opportunity and additional candidate S-SSB opportunities. As described above, each Rel-16 / Rel-17 S-SSB opportunity may have K corresponding additional candidate S-SSB opportunities.

[0073] In 710, UE 110 attempts to transmit an S-SSB at the next Rel-16 / Rel-17 opportunity. This may be caused by Figure 6 , although this is merely exemplary. As described above, because UE 110 is transmitting in an unlicensed spectrum, UE 110 will perform an LBT procedure (or some other idle channel procedure) to determine whether UE 110 can occupy a channel to transmit an S-SSB at the desired opportunity.

[0074] At 715, UE 110 determines whether the S-SSB transmission was successful in the Rel-16 / Rel-17 S-SSB opportunity. If successful, UE 110 proceeds to 720. At 720, because S-SSB transmission 710 was successful, UE 110 skips transmitting the S-SSB at the additional candidate S-SSB opportunities corresponding to the Rel-16 / Rel-17 S-SSB opportunity. Another way to express this skipping is that any remaining additional candidate S-SSB opportunities that occur before the next Rel-16 / Rel-17 S-SSB opportunity may be skipped. UE 110 then proceeds to 710 to make the next S-SSB transmission attempt at the R16 / R17 opportunity.

[0075] If the transmission 710 is unsuccessful ("No" path of 715), the UE 110 proceeds to 725. In 725, the UE 110 determines whether existAny additional S-SSB opportunities corresponding to the Rel-16 / Rel-17 S-SSB opportunities. Again, another way to express this operation is to determine whether there are any remaining additional candidate S-SSB opportunities before the next Rel-16 / Rel-17 S-SSB opportunity. If there are no additional S-SSB opportunities corresponding to the Rel-16 / Rel-17 S-SSB opportunity, then UE 110 returns to 710 to attempt to transmit on the next Rel-16 / Rel-17 S-SSB opportunity.

[0076] If there are additional S-SSB opportunities corresponding to the Rel-16 / Rel-17 S-SSB opportunities, the UE 110 proceeds to 730. In 730, the UE 110 attempts to transmit an S-SSB at subsequent additional candidate S-SSB opportunities corresponding to the missed Rel-16 / Rel-17 S-SSB opportunities (e.g., the remaining additional candidate S-SSB opportunities that occur before the next Rel-16 / Rel-17 S-SSB opportunity). The UE 110 then proceeds to 715 to confirm whether the S-SSB transmission is successful.

[0077] Figure 8 and Figure 9 This relates to scenarios where the number and positions of additional candidate S-SSB opportunities are separately (pre-)configured. In an exemplary embodiment, if there is a temporal overlap between the additional candidate S-SSB opportunities and Rel-16 / Rel-17 opportunities, the additional candidate S-SSB opportunities should be ignored because the additional candidate S-SSBs are used to compensate for potential Rel-16 / Rel-17 S-SSB transmission failures.

[0078] Figure 8 A second unlicensed S-SSB timing diagram is shown in accordance with various exemplary embodiments. It should be understood that the different heights of S-SSB opportunities 805 and 810 do not indicate different transmission frequencies (e.g., there is no y-axis indicating frequency in this diagram). Rather, the different heights of the S-SSB opportunities are used to emphasize that the R16 / R17 S-SSB opportunity 805 and the additional candidate S-SSB opportunity 810 are configured separately. It should be noted that the Rel-16 / Rel-17 S-SSB 805 and the additional S-SSB 810 can be transmitted at different frequencies.

[0079] Figure 9A second flow chart for transmitting S-SSB in unlicensed spectrum according to various exemplary embodiments is shown. In 905, a UE (e.g., UE 110) receives a sidelink BWP (pre-)configuration for both Rel-16 / Rel-17 S-SSB opportunities 805 and for additional candidate S-SSB opportunities 810. Each Rel-16 / Rel-17 S-SSB opportunity 805 has K corresponding additional candidate S-SSB opportunities 810 (e.g., Figure 8 In the example of , there are two (2) additional candidate S-SSB opportunities 810 for each Rel-16 / Rel-17 S-SSB opportunity 805. Those skilled in the art will understand that the reference to Rel-16 / Rel-17 S-SSB opportunities 805 is exemplary only and that other S-SSB periodicities are possible.

[0080] In 910, UE 110 attempts to transmit an S-SSB at an R16 / R17 S-SSB opportunity. In 915, the UE determines whether transmission 910 is successful. If the transmission is successful, UE 110 proceeds to 920. In 920, UE 110 skips S-SSB transmissions at additional candidate S-SSB opportunities corresponding to the R16 / R17 S-SSB opportunities. Similar to operation 720 described above, another way to express this skipping is that any remaining additional candidate S-SSB opportunities that occur before the next Rel-16 / Rel-17 S-SSB opportunity may be skipped. For example, UE 110 may not transmit an S-SSB at an additional candidate S-SSB opportunity that occurs before the next Rel-16 / Rel-17 S-SSB opportunity. Figure 8 The cross-hatched additional S-SSB timing is depicted.

[0081] If the UE 110 determines in 915 that the transmission 910 was unsuccessful, the UE 110 proceeds to 930. In 930, the UE 110 attempts to transmit an S-SSB at a subsequent additional candidate S-SSB opportunity 810 corresponding to the missed Rel-16 / Rel-17 S-SSB opportunity 805 (e.g., a remaining additional candidate S-SSB opportunity that occurs before the next Rel-16 / Rel-17 S-SSB opportunity). If the transmission 930 is successful, the UE 110 returns to 910 to attempt to transmit the next S-SSB at the Rel-16 / Rel-17 opportunity 805. If the transmission 930 is successful, the UE 110 proceeds to 940. In 940, if the UE 110 has transmitted 930 less than K times, the UE returns to 930. This can be understood as if Figure 8 The first (from the left) cross-hatched S-SSB in Figure 8If UE 110 has not transmitted 930 less than K times (ie, the UE has transmitted K times), UE 110 returns to 910 to attempt to transmit an S-SSB at the next R16 / R17 opportunity.

[0082] Example

[0083] In a first embodiment, a method is performed by a first user equipment (UE), the method comprising: receiving configuration information for a sidelink connection in an unlicensed band, the configuration information comprising one or more primary sidelink-synchronization signal block (S-SSB) opportunities and one or more secondary S-SSB opportunities, wherein each primary S-SSB opportunity corresponds to a predetermined number of secondary S-SSB opportunities; and determining whether the UE is allowed to transmit an S-SSB to a second UE at the primary S-SSB opportunity.

[0084] In a second embodiment, the method according to the first embodiment is described, wherein determining whether to allow the UE to transmit the S-SSB to the second UE at the primary S-SSB opportunity is based on one of a listen-before-talk (LBT) operation or a clear channel assessment (CCA) operation.

[0085] In a third embodiment, the method according to the first embodiment is further configured, wherein the configuration information further includes: a timing gap between each primary S-SSB opportunity and the first secondary S-SSB opportunity in the one or more secondary S-SSB opportunities, and a timing gap between each secondary S-SSB opportunity in the one or more secondary S-SSB opportunities.

[0086] In a fourth embodiment, the method according to the first embodiment, wherein the timing position of the secondary S-SSB opportunity corresponds to the number of the one or more secondary S-SSB opportunities.

[0087] In a fifth embodiment, the method according to the first embodiment, wherein the one or more primary S-SSB opportunities have a period of 160 ms.

[0088] In a sixth embodiment, the method according to the first embodiment is characterized in that the one or more secondary S-SSB opportunities are configured separately from the one or more primary S-SSB opportunities.

[0089] In a seventh embodiment, according to the method of the sixth embodiment, the method further includes: when the separately configured secondary S-SSB opportunity overlaps with the primary S-SSB opportunity in time, ignoring the separately configured S-SSB opportunity.

[0090] Those skilled in the art will appreciate that the exemplary embodiments described above may be implemented with any suitable software configuration or hardware configuration or a combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, mobile devices with operating systems such as iOS, Android, etc. The exemplary embodiments of the methods described above may be embodied as a program comprising lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, may be executed on a processor or microprocessor.

[0091] Although this application describes various embodiments, each having different features in various combinations, those skilled in the art will understand that any feature of one embodiment may be combined with features of other embodiments in any manner that is not expressly disavowed or that is not functionally or logically inconsistent with the operation of the device or the stated function of the disclosed embodiment.

[0092] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0093] It will be apparent to those skilled in the art that various modifications may be made to the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, it is intended that the present disclosure covers modifications and variations of the present disclosure as long as they come within the scope of the appended claims and their equivalents.

Claims

1. A method performed by a user equipment (UE), the method comprising: receiving configuration information for a sidelink connection in an unlicensed band, the configuration information including a first candidate starting symbol position for a time slot, wherein the time slot includes a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) transmission; and A second candidate starting symbol position for the time slot is determined based on at least the first candidate starting symbol position.

2. The method according to claim 1, wherein determining the second candidate starting symbol is based on the equation: Y = X + ceil ((13-X) / 2)), where Y is the second candidate starting symbol position, X is the first candidate starting symbol position, and ceil is a ceiling function of a real number.

3. The method according to claim 1, wherein determining the second candidate starting symbol is based on the equation: Y=X+floor((13-X) / 2)), where Y is the second candidate starting symbol, X is the first candidate starting symbol, and floor is a floor function of real numbers. The method according to claim 1 , wherein the configuration information includes an upper boundary value for the second candidate starting symbol position.

5. The method according to claim 4, wherein When the value of the second candidate starting symbol position exceeds the upper boundary value, the second candidate starting symbol is defined as being equal to the upper boundary value.

6. The method according to claim 4, wherein: When the value of the second candidate starting symbol position exceeds the upper boundary value, the time slot is determined to not support the second candidate starting symbol.

7. The method according to claim 1, wherein the first candidate start symbol included in the configuration information comprises an sl-StartSymbol parameter.

8. The method according to claim 1, further comprising: The number of symbols in the time slot that includes information for automatic gain control (AGC) purposes is determined.

9. The method of claim 8, wherein determining the number of symbols comprises: Determine whether the sidelink resource pool contains a single resource block (RB) set or more than one RB set, wherein, when the sidelink resource pool contains a single RB set, the number of symbols in the timeslot that include information for automatic gain control (AGC) purposes is one, and When the sidelink resource pool contains more than one RB set, the number of symbols in the time slot that include information for automatic gain control (AGC) purposes is two.

10. The method of claim 8, wherein the number of symbols including information for automatic gain control (AGC) in the time slot is based on a configuration or pre-configuration of a sidelink resource pool for the time slot.

11. The method of claim 8, wherein determining the number of symbols comprises: determining whether the PSCCH or PSSCH transmission occupies the full bandwidth of the sidelink resource pool or a portion of the bandwidth of the sidelink resource pool, wherein, when the PSCCH or PSSCH transmission occupies the full bandwidth of the sidelink resource pool, the number of symbols in the time slot that include information for automatic gain control (AGC) purposes is one, and When the PSCCH or PSSCH transmission occupies the portion of the bandwidth of the sidelink resource pool, the number of symbols in the time slot that include information for automatic gain control (AGC) purposes is two.

12. A method performed by a user equipment (UE), the method comprising: receiving a first physical sidelink control channel (PSCCH) symbol in a time slot of a sidelink transmission in an unlicensed band; performing blind decoding on the PSCCH symbol, wherein the blind decoding is successful; Determine the conditions; as well as Blind decoding operations for the second PSCCH symbol in the slot are skipped.

13. The method of claim 12, wherein the condition includes a physical sidelink shared channel (PSSCH) transmission corresponding to the PSCCH symbol occupying the full bandwidth of a sidelink resource pool.

14. The method according to claim 12, wherein the conditions include: The sidelink resource pool including the PSCCH symbols includes only one resource block (RB) set.

15. The method of claim 12, wherein the condition comprises that the UE has reached a maximum number of blind PSCCH decoding attempts.

16. A method performed by a first user equipment (UE), the method comprising: receiving configuration information for a sidelink connection in an unlicensed band, the configuration information comprising one or more primary sidelink-synchronization signal block (S-SSB) opportunities and one or more secondary S-SSB opportunities, wherein each primary S-SSB opportunity corresponds to a predetermined number of secondary S-SSB opportunities; as well as Determining whether the UE is allowed to transmit an S-SSB to a second UE at a primary S-SSB opportunity.

17. The method according to claim 16, further comprising: When the UE is allowed to transmit the S-SSB at the primary S-SSB opportunity, the UE skips transmitting the S-SSB at any one of the corresponding one or more secondary S-SSB opportunities.

18. The method according to claim 16, further comprising: When the UE is not allowed to transmit the S-SSB at the primary S-SSB opportunity, determine whether to allow the UE to transmit the S-SSB to the second UE at a first corresponding secondary S-SSB opportunity.

19. The method according to claim 18, further comprising: When the UE is allowed to transmit the S-SSB at the first secondary S-SSB opportunity, transmission of the S-SSB at any remaining corresponding one or more secondary S-SSB opportunities is skipped.

20. The method according to claim 18, further comprising: When the UE is not allowed to transmit the S-SSB at the first secondary S-SSB opportunity, determining whether there are any remaining corresponding secondary S-SSB opportunities; as well as When there is at least one remaining corresponding secondary S-SSB opportunity, determining whether to allow the UE to transmit the S-SSB to the second UE at the at least one remaining corresponding secondary S-SSB opportunity.

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