Patent Description:
In the development of a new sidelink (SL) transmission system based on the latest 5th generation-new radio (<NUM>-NR) mobile technology for vehicle-to-everything (V2X) radio communication directly between user equipments (UEs), one of challenging tasks in a design is supporting UEs to operate autonomously almost entirely on its own with minimum (pre-)configurations and sometimes without any assistance from a mobile network. That is, SL UEs operating in this autonomous mode (as known as mode <NUM>) should be able to detect and decode each other's messages and select resources individually to transmit own messages to others with a required performance in reliability and latency. However, when there are many UEs operating SL communication at the same time and sharing the same radio carrier and mode <NUM> resource pool, it is difficult to avoid transmission (Tx) collisions among the UEs and maintaining a required target performance. Furthermore, due to the nature of UE autonomous selection of SL resources in mode <NUM>, it is possible for another UE to indicate/reserve or pre-empt one or more already pre-selected or announced resources by the original Tx-UE and force the original UE to find and reselect replacement resources. If this operation happens frequently in SL communication, a system may become unstable and unreliable where information message packets could be dropped unexpectedly and not received by others. <CIT>, <CIT>, <CIT>, <CIT>, 3rd generation partnership project (3GPP) draft R1-<NUM>, and 3GPP draft R1-<NUM> are related prior arts for this field. More particularly, <CIT> falls under Art. <NUM>(<NUM>) EPC and discloses that a method of selecting, by a user equipment (UE), resources for a sidelink (SL) transmission includes providing improvements to Mode <NUM> resource selection procedures to preserve chain integrity. <CIT> falls under Art. <NUM>(<NUM>) EPC and discloses that a sidelink resource exclusion method includes identifying a first sidelink resource selected by a UE or reserved by a peer UE in a first slot from a candidate resource set in a resource selection window and in a first sidelink resource pool and excluding the first sidelink resource and/or sidelink subchannels in the first slot from the candidate resource set. <CIT> discloses that selection of a subset of time-frequency resources, for autonomous mode operation of vehicle-to-vehicle (V2V) UEs, are carried out in the context of 3GPP LTE device-to-device (D2D) direct mode communication mechanisms. <CIT> discloses that a transmitting UE may identify available D2D resources from configured resources, may identify a resource for a first transmission of a D2D transmission from the available D2D resources, and may identify a second resource for a second transmission of the D2D transmission. R1-<NUM> discloses sidelink resource allocation mechanism for NR V2X. R1-<NUM> discloses remaining issues for Mode <NUM> resource allocation.

Therefore, there is a need for a user equipment and a method of resource allocation, which can provide a good communication performance and high reliability.

In order to more clearly illustrate the embodiments of the present disclosure or related art, the following figures that will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present disclosure, a person having ordinary skill in this field can obtain other figures according to these figures.

In some embodiments of the present disclosure, it is necessary and beneficial to enhance a current resource selection mechanism to avoid triggering a process of resource reselection as much as possible to save user equipment (UE) processing power and complexity, and frequently changing indicated resources in the case when another UE's trying to adopt their resource selection based on this indication (e.g. in unicast and groupcast scenarios). In addition, in order to ensure and to improve performance of SL communication and to minimize risk of transmission (Tx) collision between UEs, it is beneficial and essential to reserve selected resources in advance or as early as possible so that others will avoid selecting the same resources.

In some embodiments of the present disclosure, timing-based resource selection scheme is provided, it aims to adapt Tx-UE's resource selection strategy to an assigned transmission profile (such as priority, packet delay budget (PDB)), to spread out SL resource congestion, to minimize Tx collision, and to reduce resource re-selection probability. Other benefits of adopting a timing-based resource selection method for an initial transmission and/or a retransmission of a transport block (TB) in new radio (NR) sidelink communication include at least one of the followings. Minimizing risk of a pre-selected resource being taken-over or reserved by others. Allowing flexibility in a sidelink control information (SCI) signaling to be able to provide early indication/reservation of future resources, and subsequently improving overall system performance.

<FIG> illustrates that, in some embodiments, user equipments (UE) <NUM> and <NUM> of resource allocation in a communication network system <NUM> according to an embodiment of the present disclosure are provided. The communication network system <NUM> includes the UE <NUM> and the UE <NUM>. The UE <NUM> may include a memory <NUM>, a transceiver <NUM>, and a processor <NUM> coupled to the memory <NUM> and the transceiver <NUM>. The UE <NUM> may include a memory <NUM>, a transceiver <NUM>, and a processor <NUM> coupled to the memory <NUM> and the transceiver <NUM>. The processor <NUM> or <NUM> may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the processor <NUM> or <NUM>. The memory <NUM> or <NUM> is operatively coupled with the processor <NUM> or <NUM> and stores a variety of information to operate the processor <NUM> or <NUM>. The transceiver <NUM> or <NUM> is operatively coupled with the processor <NUM> or <NUM>, and transmits and/or receives a radio signal.

The communication between UEs relates to vehicle-to-everything (V2X) communication including vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure/network (V2I/N) according to a sidelink technology developed under 3rd generation partnership project (3GPP) long term evolution (LTE) and new radio (NR) Release <NUM> and beyond. UEs are communicated with each other directly via a sidelink interface such as a PC5 interface. Some embodiments of the present disclosure relate to sidelink communication technology in 3GPP NR release <NUM> and beyond.

In some embodiments, the processor <NUM> is configured to perform monitoring on slots of a resource pool, exclude one or more sidelink resources from a candidate resource set in the resource pool, and select one or more sidelink resources using a timing based selection from the remaining candidate resource set or a resource selection window in the resource pool. This reduces risk of a pre-selected resource being taken-over or reserved by others and/or allows flexibility in a sidelink control information (SCI) signaling to be able to provide early indication/reservation of future sidelink resources, and subsequently improves overall system performance.

In some embodiments, the resource pool is network configured or pre-configured. In some embodiments, the resource pool comprises a selected/mode <NUM> resource pool for sidelink transmission. In some embodiments, monitoring on the slots of the resource pool is performed by decoding a physical sidelink control channel (PSCCH) and measuring a reference signal received power (RSRP) during a sensing window in the resource pool. Excluding one or more sidelink resources from the candidate resource set is according to one or more information relating to L1 priority, time and frequency resource assignments, and reservation periodicity from a sidelink control information (SCI) and a RSRP threshold.

Selecting one or more sidelink resources using the timing based selection from the remaining candidate resource set or the resource selection window is according to a chain-based selection scheme, wherein one or more slot regions within a time constraint of a maximum time gap from a previous sidelink resource and/or a next sidelink resource are identified for selection.

In some embodiments, in the time-portion based selection scheme, one or more sidelink resources are selected randomly from one or more time portions within the remaining candidate resource set or the resource selection window. In some non-claimed embodiments, in the time-portion based selection scheme, one or more time portions within the remaining candidate resource set or the resource selection window are divided equally according to at least one of the followings: <MAT> or <MAT>, where T<NUM>-T<NUM> is a time period of the resource selection window, maxNumTX is the maximum number of transmissions that is allowed for a transport block (TB), and S'A is the remaining candidate resource set; or <MAT> or <MAT>, where maxNumResource is a radio resource control (RRC) configured parameter for setting the maximum number of sidelink resources for transmitting PSCCH/physical sidelink shared channel (PSSCH) that can be signaled by a single SCI; or <MAT> or <MAT>, where numResource is a number of sidelink resources intended to be signaled by the processor <NUM> in one SCI for a TB. In some embodiments, maxNumTX is equal to <NUM>, <NUM>, or <NUM>. In some non-claimed embodiments, maxNumResource is equal to <NUM> or <NUM>. In some non-claimed embodiments, numResource is equal to <NUM>, <NUM>, or <NUM>
In some non-claimed embodiments, in the time-portion based selection scheme, a first time-portion of the remaining candidate resource set or the resource selection window is used for resource selection, the first time-portion is defined according to at least one of the followings: first X% of time of the remaining candidate resource set or the resource selection window, where X is pre-defined, network configured, or pre-configured; or first Z slots within the remaining candidate resource set or the resource selection window, where Z is pre-defined, network configured, or pre-configured; or first Y sidelink resources from the remaining candidate resource set or the resource selection window, where Y is pre-defined, network configured, or pre-configured; or a window (T<NUM>,min - T<NUM>), where T<NUM>,min is an RRC configured parameter which sets a minimum resource selection time window for an associated TB with a priority value. In some non-claimed embodiments, X may be equal to <NUM>, <NUM>, or <NUM>; In some embodiments, Z may be equal to <NUM>, <NUM>, <NUM>, or <NUM>. In some embodiments, Y may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

In some embodiments, in the chain-based selection scheme, one or more sidelink resources are selected randomly from one or more slot regions. In some embodiments, in the chain-based selection scheme, one or more slot regions within the remaining candidate resource set or the resource selection window are identified according to at least one of the followings: a lower time bound of a slot region is defined by a time gap before a time slot of the next sidelink resource, and an upper time bound of the slot region is defined by a time gap after a time slot of the previous sidelink resource; or the lower time bound and the upper time bound of the slot region are defined by a time gap before and after the time slot of the next sidelink resource, respectively; or the upper time bound of the slot region is defined by a time gap after the time slot of the previous resource. In some embodiments, the maximum of all time gaps is smaller than or equal to <NUM> slots. In some embodiments, if there is no available/candidate sidelink resource between the lower time bound and the upper time bound, the processor re-selects replacement sidelink resources including the previous and/or the next resources. In some embodiments, the re-selected replacement sidelink resources satisfy <NUM> slots time restriction between any two consecutive sidelink resources.

<FIG> illustrates a method <NUM> of resource allocation of a UE according to an embodiment of the present disclosure. In some embodiments, the method <NUM> includes: a block <NUM>, performing monitoring on slots of a resource pool, a block <NUM>, excluding one or more sidelink resources from a candidate resource set in the resource pool, and a block <NUM>, selecting one or more sidelink resources using a timing based selection from the remaining candidate resource set or a resource selection window in the resource pool. This reduces risk of a pre-selected resource being taken-over or reserved by others and/or allows flexibility in a sidelink control information (SCI) signaling to be able to provide early indication/reservation of future sidelink resources, and subsequently improves overall system performance.

In some embodiments, in the time-portion based selection scheme, one or more sidelink resources are selected randomly from one or more time portions within the remaining candidate resource set or the resource selection window. In some non-claimed embodiments, in the time-portion based selection scheme, one or more time portions within the remaining candidate resource set or the resource selection window are divided equally according to at least one of the followings: <MAT> or <MAT>, where T<NUM>-T<NUM> is a time period of the resource selection window, maxNumTX is the maximum number of transmissions that is allowed for a transport block (TB), and S'A is the remaining candidate resource set; or <MAT> or <MAT>, where maxNumResource is a radio resource control (RRC) configured parameter for setting the maximum number of sidelink resources for transmitting PSCCH/physical sidelink shared channel (PSSCH) that can be signaled by a single SCI; or <MAT> or <MAT>, where numResource is a number of sidelink resources intended to be signaled by the UE in one SCI for a TB. In some non-claimed embodiments, maxNumTX is equal to <NUM>, <NUM>, or <NUM>. In some embodiments, maxNumResource is equal to <NUM> or <NUM>. In some non-claimed embodiments, numResource is equal to <NUM>, <NUM>, or <NUM>.

In some non-claimed embodiments, in the time-portion based selection scheme, a first time-portion of the remaining candidate resource set or the resource selection window is used for resource selection, the first time-portion is defined according to at least one of the followings: first X% of time of the remaining candidate resource set or the resource selection window, where X is pre-defined, network configured, or pre-configured; or first Z slots within the remaining candidate resource set or the resource selection window, where Z is pre-defined, network configured, or pre-configured; or first Y sidelink resources from the remaining candidate resource set or the resource selection window, where Y is pre-defined, network configured, or pre-configured; or a window (T<NUM>,min - T<NUM>), where T<NUM>,min is an RRC configured parameter which sets a minimum resource selection time window for an associated TB with a priority value. In some embodiments, X may be equal to <NUM>, <NUM>, or <NUM>; In some embodiments, Z may be equal to <NUM>, <NUM>, <NUM>, or <NUM>. In some embodiments, Y may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

<FIG> is an exemplary illustration of a time-portion based resource (re)selection scheme according to the present disclosure. <FIG> illustrates that in some embodiments, a UE determines a set of slots, which represents a resource selection window (RSW) <NUM> between n+T<NUM> <NUM> and n+T<NUM> <NUM>, for a (pre-)configured sidelink selected/mode <NUM> resource pool after a resource allocation procedure trigger at time n <NUM>, and also sets up/initializes a candidate resource set for a RSW, SA <NUM>, containing all applicable sidelink (SL) resources with suitable sub-channel size for transmitting physical sidelink shared channel (PSSCH) and PSCCH. Let's denote all the applicable SL resources as square boxes for a candidate resource set SA, within which containing all of shaded boxes <NUM> and clear boxes <NUM>. The UE then excludes from, the candidate resource set SA <NUM>, all SL resources that are indicated/reserved by SCIs received during a sensing window and an associated RSRP level measured is higher than a corresponding RSRP threshold (clear boxes). Denoting these reserved resources/clear boxes as <NUM>. Then the shaded boxes <NUM> would be the remaining candidate resources (hereon denoted as set S'A) that can be potentially selected for SL transmission by the Tx-UE.

Currently for the existing resource selection procedure defined by 3GPP in LTE sidelink mode <NUM> and NR sidelink mode <NUM> operations, it mainly consists of a random selection of one or more SL resources from the remaining candidate resources within the set S'A. However, as described previously, the outcome of this random selection could be a set of SL resources that are concentrated in only a few time portions/areas of the RSW (e.g. middle or later portions of the RSW) and causing those portions of the resource pool to be more congested than others. Furthermore, this random selection scheme also presents a higher risk for the selected and even reserved resources of being indicated/announced or pre-empted by another UE if the time gap between resource selection and the actual transmission is wide. Additionally, if a randomly selected resource is not within a signaling time restriction (e.g. <NUM> slots) from a previous and/or next already pre-selected resource, then the randomly selected resource cannot be signaled together in a same or by an earlier SCI, and as such future resources cannot be reserved in advanced to minimize Tx collision. To mitigate these problems, the following resource selection schemes are proposed.

Note that the following proposed two resource selection schemes are not competing alternatives to each other, but rather they can be applied individually or in conjunction with one another depending on the scenario for resource (re)selection. Suitable scenarios or use cases for each scheme will be further described in the respective section.

For the time-portion based resource (re)selection scheme, one or multiple time-portions within the remaining candidate resource set or RSW can be identified according to one of the following methods. Benefits: By using the time-portion based scheme, it helps to spread out resource utilization, reduces resource congestion and in turn minimizes transmission collisions. Furthermore, it also reduces the chance of a pre-selected resource being taken-over or pre-empted by another UE.

In some embodiments, For the <NUM>st proposed resource (re)selection scheme, it is a time-portion based method wherein a period of the RSW (T<NUM> - T<NUM>) or the remaining candidate resource set (S'A) is arranged into one or multiple time-portions and/or the Tx-UE identifies one or more certain time-portion(s) of the RSW (T<NUM> - T<NUM>) or the remaining candidate resource set (S'A), and from which the Tx-UE selects SL resource(s) for its transmission. By selecting resource from a period that belong to a certain time-portion (e.g. first/middle/later portions), it helps to spread out probability of Tx collisions due to resource congestion, to satisfy short packet delay budget of a TB, and/or to minimize the risk of a pre-selected resource being taken-over or reserved by another UE.

In some embodiments, to arrange the period of RSW or the remaining candidate resource set (S'A) into one or more multiple time-portions, the period is divided according to at least one one of the followings.

In addition to the above described usage scenarios of dividing the RSW or remaining candidate resource set S'A into a first time-portion, a middle time-portion, and a last time-portion to be in line with SCI signaling, this time-portion based resource selection can be also useful in the following usages. For example, the first time-portion <NUM> is useful for selecting resources for the initial transmission of a TB to reduce the chance of the selected resources being pre-empted or reserved by another UE and early reservation of retransmission resources. The middle time-portion(s) <NUM> is/are useful for selecting both blind-based and HARQ feedback-based retransmission resources. And, both the middle time-portion <NUM> and the last time-portion <NUM> are useful for selecting retransmission resources to reduce resource usage congestion and minimize the chances of Tx-collision.

In some cases, the Tx-UE may identify one or more certain time-portions of the RSW <NUM> or the remaining candidate resource set (S'A) to be more important/critical or suitable/relevant for (re)selecting SL resources. For example, high priority TBs are often associated with a short latency requirement (i.e. a small PDB). In order to satisfy tight latency requirement and at the same time ensuring high transmission reliability is met for the high priority TBs (e.g. to allow sufficient resources/opportunities for retransmission), the Tx-UE identifies the first time-portion after the resource selection trigger and selects one or more SL resources within to send the initial transmission for a TB and possibly retransmissions as well. On the other hand, when the packet latency requirement for a TB is not as stringent or when it is relatively relaxed, the Tx-UE can try to (re)select resources from time-portions with less resource congestion. Usually, due to TBs with small PDB need to be sent as early as possible, early time-portions are often more congested than others. As such, the Tx-UE can try to (re)select SL resources from the middle or last time-portions of the RSW or the remaining candidate resource set S'A, for example when the measured channel busy ratio (CBR) or channel occupancy ratio (CR) for a time-portion is less than a certain M%, where M could be <NUM>, <NUM>, or less. Or the Tx-UE can avoid (re)selecting resources from time-portions that have CBR or CR higher than M%.

In some embodiments, in order to send at least an initial transmission of a TB as quickly as possible after a resource (re)selection trigger, the first time-portion within the RSW or the remaining candidate resource set (S'A) could be defined or (pre-)configured in at least one of the following ways (in reference to diagram <NUM> in <FIG>):.

If there are more than one candidate resources within the first time-portion, the Tx-UE randomly selects one or more resources for its initial transmission and/or retransmissions of a TB. For example, if the <NUM>st slot of the RSW <NUM> or the remaining candidate resource set (S'A) is identified/set as the time-portion where the Tx-UE can select its first transmission resource from (for either an initial transmission or retransmission of a TB) and there are multiple candidate resources available in the <NUM>st slot <NUM> and <NUM>, the Tx-UE randomly selects one of these two/available resources.

For the chain-based resource (re)selection scheme, one or multiple slot regions within the remaining candidate resource set or RSW is identified according to one of the following methods. Benefits: By using the chain-based scheme, it ensures a newly selected SL resource is able to signal/reserve the next selected resource in a same SCI, and/or the newly selected SL resource is able to be signaled/reserved by the previous selected resource in a same SCI, for the purpose of early/chain-based reservation to reduce Tx collision in SL communication.

In some embodiments, in addition to the above time-portion based scheme that can be used by a SL transmitting UE to (re)select resource(s) for the initial and/or retransmissions of a TB, another resource (re)selection scheme that can be additionally adopted by the Tx-UE is a chain-based method to ensure that a newly selected resource can be indicated by at least one earlier SCI and/or the next pre-selected or already announced/signaled resource can be indicated by the newly (re)selected resource. To achieve this early/chain-based reservation, the selection or replacement of resources can comply with criteria that a newly selected resource should be in a slot from the RSW and within a maximum time gap from the previous and/or the next already pre-selected or announced/signaled resources. That is, the time gap can be smaller than or equal to <NUM> slots since this is the maximum time length currently supported by the time resource assignment parameter in SCI format <NUM>-<NUM>. As such, this chain-based resource (re)selection scheme is ideally suitable for re-selection or re-evaluation of SL resources that have been pre-empted or announced/signaled by another UE before the actual SL transmission.

As part of sidelink mode <NUM> resource allocation mechanism currently defined in 3GPP, a Tx-UE is allowed to perform re-evaluation of SL resources that have been previously selected but not yet announced/signaled by the Tx-UE (these resources are also commonly known as pre-selected resources), and re-select any of the pre-selected resources if it is no longer available (e.g. no longer exist in the remaining candidate resource set S'A) due to announcement / reservation of the same resource from another UE. However, if the re-selection of a pre-selected resource (finding a replacement resource) is just a random selection within the RSW or the remaining candidate resource set (S'A), the process does not guarantee that the newly selected resource can be signaled/reserved by an earlier SCI or the newly selected resource is able to signal/reserve the next pre-selected resource in a same SCI.

<FIG> is an exemplary illustration of a chain-based resource (re)selection scheme during resource re-evaluation according to an embodiment of the present disclosure. In reference to diagram <NUM> in <FIG>, an exemplary illustration of the proposed chain-based resource (re)selection scheme is depicted for a resource re-selection scenario during a re-evaluation of pre-selected SL resources. <FIG> illustrates that, in some embodiments, SL resources R1 <NUM>, R2 <NUM>, and R3 <NUM> are already pre-selected resources from a Tx-UE but not yet announced/signaled to other UEs. Before transmitting PSCCH/PSSCH using the pre-selected SL resource R1 <NUM> and announcing/signaling SL resources R2 and R3 for the first time via SCI format <NUM>-<NUM> in the SL resource R1, the Tx-UE detects a SCI transmission in <NUM> reserving or partially reserving the same SL resource R2 <NUM> from another UE. Based on the detection of the reservation SCI in <NUM>, the Tx-UE triggers a resource re-evaluation process in slot n <NUM> before the planned SL PSCCH/PSSCH transmission in SL resource R1 <NUM> for all of the pre-selected SL resources R1, R2, and R3 to determine if they are still part of the remaining candidate resource set (S'A). Assuming the pre-selected SL resource R2 <NUM> is no longer part of the remaining candidate resource set (S'A) due to the reservation from another UE and the Tx-UE needs to perform re-selection of a new SL resource to replace SL resource R2 <NUM>. For the proposed chain-based resource re-selection scheme, instead of randomly selecting a new SL resource from the remaining candidate resource set (S'A), the Tx-UE first determines an appropriate time region within which it can perform re-selection of SL resource R2.

In some embodiments, in order to ensure that the new/replacement SL resource of R2 is within at least <NUM> slots from the previous pre-selected resource so that the newly re-selected SL resource R2 can still be reserved/signaled by PSCCH transmitted in SL resource R1 <NUM>, an upper time bound at (R1+<NUM> slots) <NUM> for the time region can be established. Similarly, in order to ensure the new/replacement resource of R2 is within at least <NUM> slots from the next pre-selected resource so that PSCCH transmitted from the newly re-selected SL resource R2 is still able to reserve/signal the next pre-selected SL resource R3 <NUM>, a lower time bound at (R3-<NUM> slots) <NUM> for the time region can be established. As such, the re-selection of SL resource R2 <NUM> can be within an overlapping time region <NUM> between the lower time bound <NUM> and the upper time bound <NUM>. If a time gap/distance separation between SL resources R1 <NUM> and R3 <NUM> is less than or equal to <NUM> slots (where the slots could be physical or logical slots), the re-selection/replacement resource for SL resource R2 <NUM> can be in any of non-taken slots within the resource chain. Otherwise, the re-selection/replacement SL resource for R2 <NUM> can be restricted within the lower time bound <NUM> and the upper time bound <NUM> as previously described and illustrated in diagram <NUM>. If there is no available/candidate resource within the time bound <NUM>, the Tx-UE re-selects another pre-selected SL resource (R1 or R3) together with R2 <NUM>, such that the newly selected replacement resources still satisfy the <NUM> slots time restriction of chain selection/reservation. For example, both R1 and R2 SL resources are re-selected such that the new SL resource R2 can be within <NUM> slots from SL resource R3 and the new SL resource R1 is within <NUM> slots from the new SL resource R2.

<FIG> is an exemplary illustration of a chain-based resource (re)selection scheme during resource pre-emption according to an embodiment of the present disclosure. In reference to diagram <NUM> in <FIG>, an exemplary illustration of the proposed chain-based resource (re)selection scheme is depicted for a resource re-selection scenario due to SL resource pre-emption. <FIG> illustrates that, in some embodiments, SL resources R1 <NUM>, R2 <NUM>, and R3 <NUM> are selected SL resources from a Tx-UE for PSCCH/PSSCH transmissions. During the transmission of PSCCH in SL resource R1 <NUM>, SL resources R2 <NUM> and R3 <NUM> are announced/signaled in the same SCI format <NUM>-<NUM> for future reservation. After the PSCCH transmission in SL resource R1 <NUM>, the Tx-UE detects a SCI with higher L1 priority than its own transmitted in <NUM>, pre-empting/reserving (either fully or partially) the same R2 SL resource <NUM> from another UE. Based on the detection of the pre-emption SCI in <NUM>, the Tx-UE triggers a resource re-selection procedure in slot n <NUM> before the planned PSCCH/PSSCH transmission in SL resource R2 <NUM> for re-selecting a new/replacement resource for the pre-empted SL resource R2 <NUM>.

In some embodiments, for the proposed chain-based resource re-selection scheme, instead of randomly selecting a new resource from the remaining candidate resource set (S'A), the Tx-UE first determines an appropriate time region within which it can perform re-selection of SL resource R2. Since the timing of resource re-selection trigger at time n <NUM> is after the PSCCH/PSSCH transmission slot of SL resource R1 (i.e., R1 is already a past and used SL resource), the slot timing for a new SL resource R2 does not need to be within <NUM> slots from SL resource R1 <NUM> for the purpose of chain reservation. However, for the proposed chain-based resource re-selection scheme, a newly re-selected SL resource R2 can still be within <NUM> slots from the already announced/signaled SL resource R3 <NUM>, in order to ensure that the new/replacement resource of SL resource R2 is still able to signal/reserve or to be signaled/reserved by SL resource R3 <NUM>. To achieve this, a time region for re-selection of R2 <NUM> can be established by the Tx-UE with a lower time bound at (R3-<NUM> slots) at <NUM> and an upper time bound (R3+<NUM> slots) at <NUM>. If there is no remaining candidate resource available within the time bound <NUM>, the Tx-UE also re-selects the other already announced/signaled SL resource R3 <NUM> together with R2 <NUM>, such that the newly selected replacement resources still satisfy the <NUM> slots time restriction of chain selection/reservation. For example, both R2 and R3 SL resources are both re-selected and that the new SL resources R2 and new R3 are within <NUM> slots to each other.

In summary, in some embodiments, in the present disclosure of inventive methods of radio resource (re)selection intended for use in new radio-sidelink (NR-SL) communication, a transmitter user equipment (Tx-UE) selects one or more SL resources to transmit a SL transport block (TB) according to a transmit time portion(s) within a resource selection window (RSW) and/or based on a time bound that is relative to the neighboring resources. By spreading out the selection of resources over time, prioritizing a certain time portion within the RSW for resource selection, and/or following a timing selection restriction, the proposed inventive methods minimizes the risk of transmission (Tx) collision and pre-selected resources being reserved or pre-empted by another UE, and at the same time takes advantage of the indication/advanced reservation of future SL resources in sidelink control information (SCI) signaling, and thus improving the overall system performance.

In some embodiments, for the proposed resource (re)selection schemes, the Tx-UE first receives network configuration or obtains pre-configuration signalling containing information for a SL "selected" (as known as mode <NUM>) transmission resource pool, and performs SL resource sensing/monitoring slots which belong to the (pre-)configured resource pool within a sensing window, where the resource sensing/monitoring operation comprises of decoding physical sidelink control channel (PSCCH) to extract information on one or more of the time and frequency resource assignments for the current and future intended/reserved resources, resource reservation period (Prsvp_RX) and priority (prioRX) from the received SCI format <NUM>-<NUM> (<NUM>st stage SCI), and measuring RSRP levels (based on PSCCH-RSRP or PSSCH-RSRP) for the received SCI format <NUM>-<NUM> in these slots.

Commercial interests for some embodiments are as follows. Providing more reliable and faster NR sidelink radio transmission performance from reduced resource congestion and transmission collisions. Providing reduced risk of resource re-selection and terminal processing power consumption from early selection and chain-reservation. Providing good communication performance. Providing high reliability. Some embodiments of the present disclosure are used by <NUM>-NR chipset vendors, V2X communication system development vendors, automakers including cars, trains, trucks, buses, bicycles, moto-bikes, helmets, and etc., drones (unmanned aerial vehicles), smartphone makers, communication devices for public safety use, AR/VR device maker for example gaming, conference/seminar, education purposes. Some embodiments of the present disclosure are a combination of "techniques/processes" that can be adopted in 3GPP specification to create an end product.

<FIG> is a block diagram of an example system <NUM> for wireless communication according to a non-claimed embodiment of the present disclosure. Embodiments described herein may be implemented into the system using any suitably configured hardware and/or software. <FIG> illustrates the system <NUM> including a radio frequency (RF) circuitry <NUM>, a baseband circuitry <NUM>, an application circuitry <NUM>, a memory/storage <NUM>, a display <NUM>, a camera <NUM>, a sensor <NUM>, and an input/output (I/O) interface <NUM>, coupled with each other at least as illustrated.

The application circuitry <NUM> may include a circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors may include any combination of general-purpose processors and dedicated processors, such as graphics processors, application processors. The processors may be coupled with the memory/storage and configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems running on the system.

Embodiments in which the baseband circuitry is configured to support radio communications of more than one wireless protocol may be referred to as multimode baseband circuitry.

In various embodiments, the baseband circuitry <NUM> may include circuitry to operate with signals that are not strictly considered as being in a baseband frequency. For example, in some embodiments, baseband circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

The RF circuitry <NUM> may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network.

In various embodiments, the RF circuitry <NUM> may include circuitry to operate with signals that are not strictly considered as being in a radio frequency. For example, in some embodiments, RF circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of the RF circuitry, the baseband circuitry, and/or the application circuitry. As used herein, "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or a memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the electronic device circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules.

In some embodiments, some or all of the constituent components of the baseband circuitry, the application circuitry, and/or the memory/storage may be implemented together on a system on a chip (SOC).

The memory/storage <NUM> may be used to load and store data and/or instructions, for example, for system. The memory/storage for one embodiment may include any combination of suitable volatile memory, such as dynamic random access memory (DRAM)), and/or non-volatile memory, such as flash memory.

In various embodiments, the I/O interface <NUM> may include one or more user interfaces designed to enable user interaction with the system and/or peripheral component interfaces designed to enable peripheral component interaction with the system. User interfaces may include, but are not limited to a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. Peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power supply interface.

In various embodiments, the sensor <NUM> may include one or more sensing devices to determine environmental conditions and/or location information related to the system. In some embodiments, the sensors may include, but are not limited to, a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, the baseband circuitry and/or RF circuitry to communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite.

In various embodiments, the display <NUM> may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system <NUM> may be a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, an ultrabook, a smartphone, a AR/VR glasses, etc. In various embodiments, system may have more or less components, and/or different architectures. Where appropriate, methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

A person having ordinary skill in the art understands that each of the units, algorithm, and steps described and disclosed in the embodiments of the present disclosure are realized using electronic hardware or combinations of software for computers and electronic hardware. Whether the functions run in hardware or software depends on the condition of application and design requirement for a technical plan.

A person having ordinary skill in the art can use different ways to realize the function for each specific application while such realizations should not go beyond the scope of the present disclosure. It is understood by a person having ordinary skill in the art that he/she can refer to the working processes of the system, device, and unit in the above-mentioned embodiment since the working processes of the above-mentioned system, device, and unit are basically the same. For easy description and simplicity, these working processes will not be detailed.

Claim 1:
A user equipment (<NUM>) for performing resource allocation, comprising:
a memory (<NUM>);
a transceiver (<NUM>); and
a processor (<NUM>) coupled to the memory (<NUM>) and the transceiver (<NUM>);
wherein the processor (<NUM>) is configured to:
perform monitoring on slots of a resource pool (<NUM>);
exclude one or more sidelink resources from a candidate resource set in the resource pool (<NUM>) according to one or more information relating to L1 priority, time and frequency resource assignments, and reservation periodicity from a sidelink control information, SCI, and a RSRP threshold; and
select one or more sidelink resources using a timing based selection from remaining candidate resource set in the resource pool (<NUM>);
wherein selecting one or more sidelink resources using the timing based selection from the remaining candidate resource set (<NUM>) is according to a chain-based selection scheme, wherein one or more slot regions within a time constraint of a maximum time gap from a previous sidelink resource and/or a next sidelink resource are identified for selection.