Patent Description:
Sidelink (SL) communication is a communication scheme in which a direct link is established between User Equipments (UEs) and the UEs exchange voice and data directly with each other without intervention of an evolved Node B (eNB). SL communication is under consideration as a solution to the overhead of an eNB caused by rapidly increasing data traffic.

Vehicle-to-everything (V2X) refers to a communication technology through which a vehicle exchanges information with another vehicle, a pedestrian, an object having an infrastructure (or infra) established therein, and so on. The V2X may be divided into <NUM> types, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2X communication may be provided via a PC5 interface and/or Uu interface.

Regarding V2X communication, a scheme of providing a safety service, based on a V2X message such as BSM (Basic Safety Message), CAM (Cooperative Awareness Message), and DENM (Decentralized Environmental Notification Message) is focused in the discussion on the RAT used before the NR. The V2X message may include position information, dynamic information, attribute information, or the like. For example, a UE may transmit a periodic message type CAM and/or an event triggered message type DENM to another UE.

For example, the CAM may include dynamic state information of the vehicle such as direction and speed, static data of the vehicle such as a size, and basic vehicle information such as an exterior illumination state, route details, or the like. For example, the UE may broadcast the CAM, and latency of the CAM may be less than <NUM>. For example, the UE may generate the DENM and transmit it to another UE in an unexpected situation such as a vehicle breakdown, accident, or the like. For example, all vehicles within a transmission range of the UE may receive the CAM and/or the DENM. In this case, the DENM may have a higher priority than the CAM.

Thereafter, regarding V2X communication, various V2X scenarios are proposed in NR. For example, the various V2X scenarios may include vehicle platooning, advanced driving, extended sensors, remote driving, or the like.

For example, based on the vehicle platooning, vehicles may move together by dynamically forming a group. For example, in order to perform platoon operations based on the vehicle platooning, the vehicles belonging to the group may receive periodic data from a leading vehicle. For example, the vehicles belonging to the group may decrease or increase an interval between the vehicles by using the periodic data.

For example, based on the advanced driving, the vehicle may be semi-automated or fully automated. For example, each vehicle may adjust trajectories or maneuvers, based on data obtained from a local sensor of a proximity vehicle and/or a proximity logical entity. In addition, for example, each vehicle may share driving intention with proximity vehicles.

For example, based on the extended sensors, raw data, processed data, or live video data obtained through the local sensors may be exchanged between a vehicle, a logical entity, a UE of pedestrians, and/or a V2X application server. Therefore, for example, the vehicle may recognize a more improved environment than an environment in which a self-sensor is used for detection.

For example, based on the remote driving, for a person who cannot drive or a remote vehicle in a dangerous environment, a remote driver or a V2X application may operate or control the remote vehicle. For example, if a route is predictable such as public transportation, cloud computing based driving may be used for the operation or control of the remote vehicle. In addition, for example, an access for a cloud-based back-end service platform may be considered for the remote driving.

Meanwhile, a scheme of specifying service requirements for various V2X scenarios such as vehicle platooning, advanced driving, extended sensors, remote driving, or the like is discussed in NR-based V2X communication.

<CIT> relates to a method for allowing a V2X reception terminal to perform a HARQ in a wireless communication system, comprising: receiving a V2X signal which is broadcasted from a V2X transmission terminal; and transmitting, to the V2X transmission terminal, an ACK/NACK for the broadcasted V2X signal, wherein the ACK/NACK is configured to identify a location area, which corresponds to a location of a V2X reception terminal, among a plurality of location areas divided for ACK/NACK transmission on the basis of a location of the V2X transmission terminal.

<CIT> relates to a UE to be used as receiving UE in a mobile communication system supporting D2D communication and the UE includes a feedback unit that receives a D2D signal from transmitting UE, and that transmits, to the transmitting UE, a feedback signal with respect to the D2D signal by using a predetermined resource; and a receiver that receives a retransmission D2D signal transmitted from the transmitting UE based on the feedback signal.

<CIT> relates to a method for performing a D2D operation using an exceptional resource by a UE in a wireless communication system, and the UE uses a method comprising: performing D2D communication in one cell of a first cell having a first frequency and a second cell having a second frequency, wherein the first cell is a serving cell of the UE, and whether the exceptional resource provided by the first cell can be used depends on in which cell of the first cell and the second cell the D2D communication is performed.

The document 3GPP DRAFT; R2-<NUM> discloses discussion about exceptional pool for resource pool sharing between UEs using mode <NUM> and UEs using mode <NUM>.

The document 3GPP DRAFT; R2-<NUM> discloses mobility enhancements for mode-<NUM> and mode-<NUM>.

The document 3GPP DRAFT; R2-<NUM> discloses discussion on HARQ support for NR sidelink.

According to a first aspect, we describe a method for performing, by a first device, wireless communication, the method comprising: obtaining information related to a normal resource pool and information related to one exceptional resource pool; determining to use the one exceptional resource pool, based on occurrence of an exceptional case; selecting a first resource from the one exceptional resource pool; transmitting, to a second device, sidelink control information, SCI, for scheduling a physical sidelink shared channel, PSSCH, through a physical sidelink control channel, PSCCH, based on the first resource; transmitting, to the second device, a medium access control, MAC, protocol data unit, PDU, through the PSSCH, based on the first resource; and receiving a first hybrid automatic repeat request, HARQ, feedback related to the MAC PDU based on a first HARQ feedback resource included in the one exceptional resource pool, wherein, the one exceptional resource pool includes at least one HARQ feedback resource, for the MAC PDU in which a HARQ feedback is set to enabled, wherein the at least one HARQ feedback resource includes the first HARQ feedback resource, wherein the normal resource pool is used based on the first device being not in an exceptional condition, and wherein the exceptional resource pool is used based on the first device being in an exceptional condition.

According to a second aspect, we describe a first device for performing wireless communication, the first device comprising: one or more memories storing instructions; and one or more processors connected to the one or more memories, wherein the one or more processors execute the instructions to: obtain information related to a normal resource pool and information related to one exceptional resource pool; determine to use the one exceptional resource pool, based on occurrence of an exceptional case; select a first resource from the one exceptional resource pool; transmit, to a second device, sidelink control information, SCI, for scheduling a physical sidelink shared channel, PSSCH, through a physical sidelink control channel PSCCH, based on the first resource; transmit, to the second device, a medium access control, MAC, protocol data unit, PDU, through the PSSCH, based on the first resource; and receive a first hybrid automatic repeat request, HARQ, feedback related to the MAC PDU based on a first HARQ feedback resource included in the one exceptional resource pool, wherein, the one exceptional resource pool includes at least one HARQ feedback resource, for the MAC PDU in which a HARQ feedback is set to enabled, wherein the one exceptional resource pool includes the first HARQ feedback resource based on the MAC PDU in which a HARQ feedback is set to enabled, wherein the normal resource pool is used based on the first device being not in an exceptional condition, and wherein the exceptional resource pool is used based on the first device being in an exceptional condition.

The user equipment (UE) may efficiently perform SL communication.

The embodiments of <FIG>, <FIG> and <FIG> are not according to the present invention and are present for illustration purposes only.

In the present specification, "A or B" may mean "only A", "only B" or "both A and B. " In other words, in the present specification, "A or B" may be interpreted as "A and/ or B". For example, in the present specification, "A, B, or C" may mean "only A", "only B", "only C", or "any combination of A, B, C".

A slash (/) or comma used in the present specification may mean "and/or". For example, "A, B, C" may mean "A, B, or C".

In the present specification, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, in the present specification, the expression "at least one of A or B" or "at least one of A and/or B" may be interpreted as "at least one of A and B".

In addition, in the present specification, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B, and/or C" may mean "at least one of A, B, and C".

In addition, a parenthesis used in the present specification may mean "for example". Specifically, when indicated as "control information (PDCCH)", it may mean that "PDCCH" is proposed as an example of the "control information". In other words, the "control information" of the present specification is not limited to "PDCCH", and "PDDCH" may be proposed as an example of the "control information". In addition, when indicated as "control information (i.e., PDCCH)", it may also mean that "PDCCH" is proposed as an example of the "control information".

A technical feature described individually in one figure in the present specification may be individually implemented, or may be simultaneously implemented.

<FIG> shows a structure of an NR system, in accordance with an embodiment of the present disclosure.

<FIG> shows a functional division between an NG-RAN and a 5GC, in accordance with an embodiment of the present disclosure.

Referring to <FIG>, the gNB may provide functions, such as Inter Cell Radio Resource Management (RRM), Radio Bearer (RB) control, Connection Mobility Control, Radio Admission Control, Measurement Configuration & Provision, Dynamic Resource Allocation, and so on. An AMF may provide functions, such as Non Access Stratum (NAS) security, idle state mobility processing, and so on. A UPF may provide functions, such as Mobility Anchoring, Protocol Data Unit (PDU) processing, and so on. A Session Management Function (SMF) may provide functions, such as user equipment (UE) Internet Protocol (IP) address allocation, PDU session control, and so on.

Layers of a radio interface protocol between the UE and the network can be classified into a first layer (L1), a second layer (L2), and a third layer (L3) based on the lower three layers of the open system interconnection (OSI) model that is well-known in the communication system. Among them, a physical (PHY) layer belonging to the first layer provides an information transfer service by using a physical channel, and a radio resource control (RRC) layer belonging to the third layer serves to control a radio resource between the UE and the network. For this, the RRC layer exchanges an RRC message between the UE and the BS.

<FIG> shows a radio protocol architecture, in accordance with an embodiment of the present disclosure. Specifically, <FIG> shows a radio protocol architecture for a user plane, and <FIG> shows a radio protocol architecture for a control plane. The user plane corresponds to a protocol stack for user data transmission, and the control plane corresponds to a protocol stack for control signal transmission.

A radio resource control (RRC) layer is defined only in the control plane. The RRC layer serves to control the logical channel, the transport channel, and the physical channel in association with configuration, reconfiguration and release of RBs. The RB is a logical path provided by the first layer (i.e., the physical layer or the PHY layer) and the second layer (i.e., the MAC layer, the RLC layer, and the packet data convergence protocol (PDCP) layer) for data delivery between the UE and the network.

The physical channel includes several OFDM symbols in a time domain and several sub-carriers in a frequency domain. One sub-frame includes a plurality of OFDM symbols in the time domain. A resource block is a unit of resource allocation, and consists of a plurality of OFDM symbols and a plurality of sub-carriers. Further, each subframe may use specific sub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of a corresponding subframe for a physical downlink control channel (PDCCH), i.e., an L1/L2 control channel. A transmission time interval (TTI) is a unit time of subframe transmission.

A subframe (SF) may be divided into one or more slots, and the number of slots within a subframe may be determined in accordance with subcarrier spacing (SCS).

Table <NUM> shown below represents an example of a number of symbols per slot (Nslotsymb ), a number slots per frame (Nframe,uslot), and a number of slots per subframe (Nsubframe,uslot) in accordance with an SCS configuration (u), in a case where a normal CP is used.

Table <NUM> shows an example of a number of symbols per slot, a number of slots per frame, and a number of slots per subframe in accordance with the SCS, in a case where an extended CP is used.

<FIG> shows a structure of a slot of an NR frame, in accordance with an embodiment of the present disclosure.

Meanwhile, a radio interface between a UE and another UE or a radio interface between the UE and a network may consist of an L1 layer, an L2 layer, and an L3 layer. In various embodiments of the present disclosure, the L1 layer may imply a physical layer. In addition, for example, the L2 layer may imply at least one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. In addition, for example, the L3 layer may imply an RRC layer.

The BWP may be a set of consecutive physical resource blocks (PRBs) in a given numerology. The PRB may be selected from consecutive sub-sets of common resource blocks (CRBs) for the given numerology on a given carrier.

When using bandwidth adaptation (BA), a reception bandwidth and transmission bandwidth of a UE are not necessarily as large as a bandwidth of a cell, and the reception bandwidth and transmission bandwidth of the BS may be adjusted. For example, a network/BS may inform the UE of bandwidth adjustment. For example, the UE receive information/configuration for bandwidth adjustment from the network/BS. In this case, the UE may perform bandwidth adjustment based on the received information/configuration. For example, the bandwidth adjustment may include an increase/decrease of the bandwidth, a position change of the bandwidth, or a change in subcarrier spacing of the bandwidth.

For example, the bandwidth may be decreased during a period in which activity is low to save power. For example, the position of the bandwidth may move in a frequency domain. For example, the position of the bandwidth may move in the frequency domain to increase scheduling flexibility. For example, the subcarrier spacing of the bandwidth may be changed. For example, the subcarrier spacing of the bandwidth may be changed to allow a different service. A subset of a total cell bandwidth of a cell may be called a bandwidth part (BWP). The BA may be performed when the BS/network configures the BWP to the UE and the BS/network informs the UE of the BWP currently in an active state among the configured BWPs.

For example, the UE may not receive PDCCH, PDSCH, or CSI-RS (excluding RRM) outside the active DL BWP. For example, the UE may not transmit PUCCH or PUSCH outside an active UL BWP. For example, in a downlink case, the initial BWP may be given as a consecutive RB set for an RMSI CORESET (configured by PBCH). For example, in an uplink case, the initial BWP may be given by SIB for a random access procedure. For energy saving, if the UE fails to detect DCI during a specific period, the UE may switch the active BWP of the UE to the default BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used in transmission and reception. For example, a transmitting UE may transmit an SL channel or an SL signal on a specific BWP, and a receiving UE may receive the SL channel or the SL signal on the specific BWP. In a licensed carrier, the SL BWP may be defined separately from a Uu BWP, and the SL BWP may have configuration signaling separate from the Uu BWP. For example, the UE may receive a configuration for the SL BWP from the BS/network. The SL BWP may be (pre-)configured in a carrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UE in the RRC_CONNECTED mode, at least one SL BWP may be activated in the carrier.

<FIG> shows an example of a BWP, in accordance with an embodiment of the present disclosure.

<FIG> shows a radio protocol architecture for a SL communication, in accordance with an embodiment of the present disclosure. More specifically, <FIG> shows a user plane protocol stack, and <FIG> shows a control plane protocol stack.

Hereinafter, a sidelink synchronization signal (SLSS) and synchronization information will be described.

The SLSS may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS), as an SL-specific sequence. The PSSS may be referred to as a sidelink primary synchronization signal (S-PSS), and the SSSS may be referred to as a sidelink secondary synchronization signal (S-SSS). For example, length-<NUM>-sequences may be used for the S-PSS, and length-<NUM> gold sequences may be used for the S-SSS. For example, a UE may use the S-PSS for initial signal detection and for synchronization acquisition. For example, the UE may use the S-PSS and the S-SSS for acquisition of detailed synchronization and for detection of a synchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast) channel for transmitting default (system) information which must be first known by the UE before SL signal transmission/reception. For example, the default information may be information related to SLSS, a duplex mode (DM), a time division duplex (TDD) uplink/ downlink (UL/DL) configuration, information related to a resource pool, a type of an application related to the SLSS, a subframe offset, broadcast information, or the like. For example, for evaluation of PSBCH performance, in NR V2X, a payload size of the PSBCH may be <NUM> bits including <NUM>-bit CRC.

<FIG> shows a UE performing V2X or SL communication, in accordance with an embodiment of the present disclosure.

Referring to <FIG>, in V2X or SL communication, the term 'UE' may generally imply a UE of a user. However, if a network equipment such as a BS transmits/ receives a signal according to a communication scheme between UEs, the BS may also be regarded as a sort of the UE. For example, a UE <NUM> may be a first apparatus <NUM>, and a UE <NUM> may be a second apparatus <NUM>.

<FIG> shows a procedure of performing V2X or SL communication by a UE based on a transmission mode, in accordance with an embodiment of the present disclosure. In various embodiments of the present disclosure, the transmission mode may be called a mode or a resource allocation mode. Hereinafter, for convenience of explanation, in LTE, the transmission mode may be called an LTE transmission mode. In NR, the transmission mode may be called an NR resource allocation mode.

For example, <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, <FIG> shows a UE operation related to an NR resource allocation mode <NUM>. For example, the LTE transmission mode <NUM> may be applied to general SL communication, and the LTE transmission mode <NUM> may be applied to V2X communication.

For example, <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, <FIG> shows a UE operation related to an NR resource allocation mode <NUM>.

Referring to <FIG>, in the LTE transmission mode <NUM>, the LTE transmission mode <NUM>, or the NR resource allocation mode <NUM>, a BS may schedule an SL resource to be used by the UE for SL transmission. For example, the BS may perform resource scheduling to a UE <NUM> through a PDCCH (more specifically, downlink control information (DCI)), and the UE 1may perform V2X or SL communication with respect to a UE <NUM> according to the resource scheduling. For example, the UE <NUM> may transmit a sidelink control information (SCI) to the UE <NUM> through a physical sidelink control channel (PSCCH), and thereafter transmit data based on the SCI to the UE <NUM> through a physical sidelink shared channel (PSSCH).

Referring to <FIG>, in the LTE transmission mode <NUM>, the LTE transmission mode <NUM>, or the NR resource allocation mode <NUM>, the UE may determine an SL transmission resource within an SL resource configured by a BS/network or a pre-configured SL resource. For example, the configured SL resource or the pre-configured SL resource may be a resource pool. For example, the UE may autonomously select or schedule a resource for SL transmission. For example, the UE may perform SL communication by autonomously selecting a resource within a configured resource pool. For example, the UE may autonomously select a resource within a selective window by performing a sensing and resource (re)selection procedure. For example, the sensing may be performed in unit of subchannels. In addition, the UE <NUM> which has autonomously selected the resource within the resource pool may transmit the SCI to the UE <NUM> through a PSCCH, and thereafter may transmit data based on the SCI to the UE <NUM> through a PSSCH.

<FIG> shows three cast types, in accordance with an embodiment of the present disclosure. Specifically, <FIG> shows broadcast-type SL communication, <FIG> shows unicast type-SL communication, and <FIG> shows groupcast-type SL communication. In case of the unicast-type SL communication, a UE may perform one-to-one communication with respect to another UE. In case of the groupcast-type SL transmission, the UE may perform SL communication with respect to one or more UEs in a group to which the UE belongs. In various embodiments of the present disclosure, SL groupcast communication may be replaced with SL multicast communication, SL one-to-many communication, or the like.

The exceptional transmit (TX) pool is a set of time-frequency resources used for sidelink communication in particular exceptional scenarios. For example, in LTE V2X, the exceptional TX pool, was used in the following instances: upon detection of any physical layer problems such as Radio Link Failure (RLF), upon near completion of initiated connection (re)establishment, during a handover, and when the sensing results of the normal TX pool are unavailable.

For example, NR V2X introduces advanced use cases which require higher reliability and lower latency sidelink communications. Additional events are also proposed to be considered: cell reselections and a beam failure/reselection.

In the prior art, it has been agreed that the LTE V2X concept of the exceptional pool may be adopted to NR V2X. However, LTE served the basic requirements of broadcast safety V2X services and therefore certain enhancements would be deemed necessary to account for the stringent QoS requirements of the advanced use cases. Alternative solutions exist where the exceptional TX pool can be separated according to cast type, which can increase reliability, but may result in lower resource efficiency.

For example, UE physical layer transmission parameters may be also adapted in order to ensure reliable and stable link performance in different radio channel conditions. Such adaptations may also assist in satisfying the stringent QoS requirements. Open-loop and closed-loop power control mechanisms are exemplary physical layer parameters, which can be used to optimize the transmitter's power in relation to the receiver.

For example, open-loop power control is a mechanism whereby the transmitter determines its own transmit power based on a set of parameters. For example, closed-loop power control refers to the mechanism where the receiver dynamically controls the transmitter power, (e.g. when UE transmit power is controlled by the BS via the transmission power control command (TPC)).

As a result, it is possible to adapt the UE transmission power based on the information sent in a particular channel, e.g. PRACH, PUCCH, PUSCH.

The following Math <FIG> may describe the UE closed-loop power control in the PUSCH in NR.

Referring to the Math <FIG>, PCMAX may refer to the maximum power allocated per carrier. P<NUM>(j) may define the target receiver power configured by the network. α<NUM>(j) may be the fractional pathloss component configured by the network. PL(q) may refer to the estimate on the uplink pathloss. µ may be the subcarrier spacing where Δf = <NUM>µ. MRB may a number of resource blocks for PUSCH transmission. ΔTF may refer to the modulation scheme and channel coding rate. δ(l) may be the power adjustment due to closed-loop power control. These parameters are a function of the power control mechanism. Similar mechanisms may also be used along the sidelink (SL).

Targets the disclosure aims to address will be described below. For example, the targets may include ensuring higher reliable SL communications to satisfy the stringent NR V2X requirements, and enhancing the performance of the exceptional resource pool for SL communications, especially in scenarios where the resource pool is experiencing a high traffic load. Such high traffic loads in the resource pool may be caused by multiple UEs performing different cast type sidelink communications (i.e. broadcast, groupcast and unicast) and depending on the QoS of each these V2X services, this may cause performance degradation in terms of reliability.

The following description aims to address the aforementioned issue related to the enhancement of the exceptional pool.

Referring to an example of this disclosure, a method of resource selection wherein a UE is allowed to select at least one exceptional Tx pool from a set of exceptional pools may be proposed. For example, a base station (e.g. gNB) may configure the set of exceptional pools in system information. The set of exceptional pools may be differentiated according to the occupancy or QoS fulfillment criteria. For example, in the context of QoS, there may be a set of exceptional pools, which may contain at least one exceptional pool with allocation of feedback resources (ensure higher reliability for SL transmissions) and at least one exceptional pool without feedback resources (with no reliability requirements). For example, examples of feedback may include but not limited to HARQ feedback, channel state information (CSI), closed-loop power control parameters.

For example, the base station may configure such exceptional resource pools based on a validity area where system information related to this resource pool may be valid. For example, the validity area can comprise of a single or multiple sidelink zone(s), a sector, a single beam or a set of beams, a set of cells, e.g. source cell and target cell. For example, the selected exceptional pool may use a resource selection mechanism that includes random resource selection or short-term sensing resource selection. The resource selection mechanism may be selected or determined based on the following considerations: On the QoS (PQI/VQI) of the associated V2X packet or QoS flow. Or, the reported resource occupancy (e.g. CBR) of the exceptional pool.

For example, here, short-term sensing is an operation to perform additional sensing for a predetermined time (a period from the selection of a transmission resource until a signal is transmitted) after selection of a transmission resource, and to discard the selected transmission resource and select another resource when a possibility of collision is detected.

Referring to an example of this disclosure, a method where a UE may select an exceptional pool with higher reliability (e.g. allocation of feedback resources) upon prior explicit or implicit indication as follows may be proposed. For example, explicit (direct) indication may include a procedure that a UE may signal an indication to the Base Station (BS) regarding its need for an exceptional resource pool with higher reliability (allocation of feedback resources). This may be performed prior to the actual utilization of the exceptional resource pool. For example, implicit indication may include a procedure that if a UE is previously using a Mode <NUM> resource pool with a capability of providing feedback, then the UE may be entitled to maintain the same configuration and use an exceptional pool with feedback resources to maintain reliable service continuity.

Referring to an example of this disclosure, a method wherein a UE can be simultaneously configured with an exceptional pool from two Radio Access Technologies (RATs), e.g. an exceptional pool from an LTE system information configuration and an exceptional pool from an NR system information configuration may be proposed. For example, the UE may also be simultaneously configured with an NR exceptional pool from an LTE RAT and an NR RAT. For example, the UE may also be simultaneously configured with an LTE exceptional pool from an LTE RAT and an NR exceptional pool from an NR RAT.

Referring to an example of this disclosure, a method wherein a UE can request the exceptional pool configuration using RRC signaling may be proposed.

Referring to an example of this disclosure, a method wherein a UE may measure and report the resource occupancy of at least one exceptional pool using e.g. channel busy ratio (CBR), time and frequency indices, etc may be proposed.

Referring to an example of this disclosure, a method wherein a UE selects a specific transmission (Tx) profile for operation in an exceptional pool may be proposed.

Referring to an example of this disclosure, a UE may normally select the configured exceptional pool from the stored system information (e.g. SIB21), in the event of an exceptional event such as a physical layer radio link failure (RLF). A key aim of the resource pool may be to improve service continuity in the event of an emergency situation, which originated from the initial D2D use cases.

This description aims to enhance the exceptional pool configuration to a UE, in order to enhance the overall reliability and alleviate the resource burden that may occur by having an exceptional pool with high traffic.

Referring to an example of this disclosure, the BS (base station) configures the cell-specific or area-specific exceptional resource pool configuration, which includes a set of exceptional pools. For example, the exceptional pools may be divided based on the occupancy level or provided level of QoS, e.g. reliability requirements that may include resource pools that comprise of feedback resources or resource pools that are not allocated with feedback resources.

<FIG> shows a procedure of performing a SL communication by a TX UE.

Referring to <FIG>, in step S1210, a base station transmits configuration information related to exceptional pools to a TX UE. In step S1220, the TX UE selects an exceptional pool including a feedback resource or another exceptional pool not including the feedback resource, based on QoS of a packet to be transmitted. The selection may be triggered based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable. And the TX UE selects a resource from the selected exceptional pool. In step S1230, the TX UE performs a SL communication with a RX UE using the resource. If the selected exceptional pool includes a feedback resource, in step S1240, the RX UE transmits a feedback to the TX UE. The feedback includes HARQ feedback.

For example, the UE may furthermore use random resource selection or short-term sensing and resource (re-) selection in the selected exceptional pool based on the QoS of the packet. Short-term sensing may be used for increased reliability relating to SL transmissions in the selected exceptional pool. For example, the UE may also determine the resource selection method to use, depending on the prior measured occupancy of the exceptional pool.

Referring to an example of this disclosure, specified QoS and occupancy criteria may have to enable the UE to select the required exceptional pool from the configured set of exceptional pools. This may result in certain UEs only using a particular exceptional pool due to its QoS service level requirements. For example, this may be in the form of direct signaling or an indirect indication.

For example, a direct signaling may be in the form of a single bit flag in the on-demand SI request related to the configuration of the type of exceptional pool. The single bit flag may differentiate between a request for a normal exceptional pool without feedback resources (<NUM>) or an exceptional pool with feedback resources (<NUM>).

For example, an indirect indication may be that if a BS is aware of ongoing SL communications using Mode <NUM>, then it may preemptively signal the exceptional pool configuration with feedback resources in order to maintain reliable service continuity.

For example, the BS may signal the UE using a System Information (SI) update using dedicated signaling e.g. via an RRCReconfiguration message.

Referring to an example of this disclosure, a UE may be simultaneously configured with an exceptional pool from two Radio Access Technologies (RATs). This feature enables a UE to utilize a simultaneous cross-RAT exceptional pool configuration by allowing a UE to select between an LTE exceptional pool or an NR exceptional pool for SL transmission, depending on the QoS requirements. For example, a service in UE with higher QoS requirements will select the NR exceptional pool from the NR RAT as opposed to the LTE configured exceptional pool from the LTE RAT.

For example, the UE can be simultaneously configured with two exceptional pools as dictated by the V2X services in the upper layer and/or based on the QoS requirements. For example, if a UE is simultaneously configured to perform Mode <NUM> and Mode <NUM> transmissions, then in an exceptional event the UE can fallback to using the NR exceptional pool for the Mode <NUM> transmission and an LTE exceptional pool for a Mode <NUM> transmission.

Referring to an example of this disclosure, an on-demand SI request for a particular exceptional pool configuration may be made by a UE and transmitted to the BS. For example, an on-demand SI request for a highly reliable exceptional pool (e.g. an exceptional pool with feedback resources) may be an example. For example, this request can be sent pre-emptively, before the use of an exceptional pool.

Referring to <FIG>, in step S1310, a TX UE may transmit a request related to an exceptional pool to a base station. In step S1320, the base station transmits configuration information related to exceptional pools to the TX UE based on the request. In step S1330, the TX UE selects an exceptional pool including a feedback resource or another exceptional pool not including the feedback resource, based on QoS of a packet to be transmitted. The selection may be triggered based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable. And the TX UE selects a resource from the selected exceptional pool. In step S <NUM>, the TX UE performs a SL communication with a RX UE using the resource. If the selected exceptional pool includes a feedback resource, in step S1350, the RX UE transmits a feedback to the TX UE. The feedback includes HARQ feedback.

Referring to an example of this disclosure, the UE may measure the resource occupancy of at least one exceptional pool or set of exceptional pools and report the occupancy status to the BS. For example, the report may be in the form of CBR value(s), or explicit free or used resources and its corresponding time and frequency location within the resource pool. For example, these measurements may take place periodically or be event-triggered.

Referring to an example of this disclosure, each application/service is mapped to a particular Tx profile in order to ensure compatibility, especially on the physical layer among different UEs. For example, there are more constraints in terms of resource availability and QoS guarantee of the exceptional pool, when compared to normal Tx pool operations. In this regard, an UE's service/application can be mapped to an exceptional Tx profile when using the exceptional pool as a fallback from a standard Tx profile operating on a normal Tx resource pool. The key motivation is that the exceptional pool may not fulfill all the requirements specified in the standard Tx profile of a UE and hence an alternative 'exceptional' Tx profile should be selected, which has adapted the relevant physical layer transmission parameters accordingly.

For example in the context of HARQ feedback, a standard TX profile may indicate the use of HARQ feedback in sidelink (SL) for a certain application/service, however it is not guaranteed that a specific exceptional pool enables SL HARQ feedback by allocating certain resources for HARQ feedback transmissions. In this case, when the UE falls back to the exceptional pool, HARQ feedback will be automatically disabled if the exceptional pool does not configure resources for HARQ feedback transmissions or provides a different configuration with a less frequent appearance of HARQ feedback resource making it difficult to meet the latency requirement. In that case, the UE should be able to adapt its transmission parameters accordingly in order to match the QoS of the standard Tx profile, in a best effort manner when disabling HARQ feedback.

For example, the physical link layer parameters in an exceptional Tx profile may be adapted when operating in an exceptional pool. For example, the physical link payer parameters may include increasing the amount of blind retransmissions. For example, the physical link payer parameters may include adopting a lower MCS, more generally using a different set of MCS. For example, the physical link payer parameters may include adopting a lower order MIMO transmission scheme, more generally using a different MIMO transmission scheme including a different minimum and/or maximum number of layers transmitted. For example, the physical link payer parameters may include disabling open- and/or closed-loop power control or using of a different power control parameter configuration (including the target received power P<NUM>, the pathloss compensation parameter alpha (α)). For example, the physical link payer parameters may include disabling beam-based power control.

Referring to an example of this disclosure, a set of exceptional Tx profiles may be created, which cater to the different combinations of PHY layer link parameters. This would require Tx profile switching in the event that the exceptional pool is selected or in use. For example, the corresponding service/application shall also be notified when the Tx profile has changed.

Referring to an example of this disclosure, data unit(s) (e.g. PDCP SDU, PDCP PDU, RLC SDU, RLC PDU, RLC SDU, MAC SDU, MAC CE, MAC PDU) in the present disclosure is(are) transmitted/received on a physical channel (e.g. PDSCH, PUSCH) based on resource allocation (e.g. UL grant, DL assignment).

In the present disclosure, uplink resource allocation is also referred to as uplink grant, and downlink resource allocation is also referred to as downlink assignment. The resource allocation includes time domain resource allocation and frequency domain resource allocation. In the present disclosure, an uplink grant is either received by the UE dynamically on PDCCH, in a Random Access Response, or configured to the UE semi-persistently by RRC. In the present disclosure, downlink assignment is either received by the UE dynamically on the PDCCH, or configured to the UE semi-persistently by RRC signalling from the BS.

<FIG> shows a procedure of selecting a transmission resource by a UE.

<FIG> is a flowchart for explaining the operation of the UE (or VRU, V2X, RSU, etc.) related to the embodiments of the present disclosure described above. Referring to <FIG>, in step S1410, the UE receives configuration information for exceptional resource pools from the base station. The exceptional resource pools are set differently according to quality of service (QoS) or occupancy. Here, the use of an exceptional resource pool of the UE may be indicated implicitly or explicitly as indicated above. Next, in step S1420, the UE selects or determines a corresponding exceptional pool from among the exceptional pools based on the QoS or occupancy associated therewith. Next, in step S1430, the UE may determine a resource selection method based on QoS, QoS flow, or CBR for an exceptional pool. Here, the resource selection method may include the randomly resource selection method and/or a resource selection method based on short-term sensing. The UE transmits the message on the selected transmission resource based on the determined resource selection method.

Referring to an example of this disclosure, a processor may implement the functions, processes, and / or methods suggested herein. The processor controls the transceiver to receive configuration information on exceptional resource pools from the base station. The exceptional resource pools are set differently according to quality of service (QoS) or occupancy. Here, the use of an exceptional resource pool of the UE may be indicated implicitly or explicitly as indicated above. Next, the processor may select or determine a corresponding exceptional pool among the exceptional pools based on the QoS or occupancy associated therewith. Next, the processor may determine a resource selection method based on QoS, QoS flow, or CBR for an exceptional pool. Here, the resource selection method may include the randomly resource selection method and / or a resource selection method based on short-term sensing. The processor may control the transceiver to transmit a message on the selected transmission resource based on the determined resource selection method.

For example, the selection of more than one exceptional Tx pool enables greater flexibility when dealing with exceptional radio events of different UEs with varying QoS requirements. For example, the exceptional pool with allocation of feedback resources also allows UEs to perform more reliable sidelink communications in such exceptional scenarios. For example, the exceptional Tx profile enables the system to adapt the relevant physical layer parameters to the usage of the exceptional pool.

<FIG> shows a procedure of performing resource selection by a first apparatus.

Referring to <FIG>, in step S1510, a first apparatus receives system information including configuration information related to exceptional pools from a base station. For example, the exceptional pools may include a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource. In step S1520, the first apparatus may select the first exceptional pool or the second exceptional pool, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable. In step S1530, the first apparatus selects a resource from the selected exceptional pool. In step S <NUM>, the first apparatus performs a sidelink (SL) communication using the resource. For example, the first exceptional pool or the second exceptional pool may be selected based on quality of service (QoS) of a packet to be transmitted.

For example, the first exceptional pool may be selected based on the QoS which requires higher reliability.

Performing the SL communication using the resource comprises transmitting the packet to a second apparatus; and receiving a feedback from the second apparatus.

For example, the second exceptional pool may be selected based on the QoS which doesn't require reliability.

For example, performing the SL communication using the resource comprising: transmitting the packet to a second apparatus. For example, no feedback may be received from the second apparatus.

For example, the first exceptional pool may be selected based on at least one of a cell reselection, a beam failure, or a beam reselection.

For example, the configuration information may be configured based on a validity area, and the validity area may include at least one of a single sidelink zone, a sector, a single beam, or a set of cells.

For example, the resource may be selected based on a resource selection mechanism which includes random resource selection or short-term sensing resource selection.

Additionally, for example, the first apparatus may transmit an information, which is related to a need for an exceptional pool with higher reliability, to the base station, the exceptional pools may include an exceptional pool with higher reliability.

For example, the first exceptional pool and the second exceptional pool may be from different radio access technologies (RATs).

For example, the first exceptional pool may be from NR RAT, and the first exceptional pool may be selected based on the QoS which requires higher reliability.

Additionally, for example, the first apparatus may transmit a request for a configuration related to an exceptional pool to the base station, the configuration information may be received based on the request.

Examples described above may be applied to variable devices which will be described below. For example, a processor (<NUM>) of a first apparatus (<NUM>) may control a transceiver (<NUM>) to receive system information including configuration information related to exceptional pools from a base station (<NUM>). For example, the processor (<NUM>) of the first apparatus (<NUM>) may select the first exceptional pool or the second exceptional pool, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable. For example, the processor (<NUM>) of the first apparatus (<NUM>) may select a resource from the selected exceptional pool. For example, the processor (<NUM>) of the first apparatus (<NUM>) may control the transceiver to perform a sidelink (SL) communication using the resource.

Referring to an example of this disclosure, a first apparatus for performing wireless communication may be provided. The first apparatus may comprise one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: receive system information including configuration information related to exceptional pools from a base station, wherein the exceptional pools includes a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource; select the first exceptional pool or the second exceptional pool, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable; select a resource from the selected exceptional pool; and perform a sidelink (SL) communication using the resource, wherein the first exceptional pool or the second exceptional pool is selected based on quality of service (QoS) of a packet to be transmitted.

Referring to an example of this disclosure, an apparatus configured to control a first user equipment (UE) may be provided. The apparatus may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions. For example, the one or more processors execute the instructions to: receive system information including configuration information related to exceptional pools from a base station, wherein the exceptional pools includes a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource; select the first exceptional pool or the second exceptional pool, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable; select a resource from the selected exceptional pool; and perform a sidelink (SL) communication using the resource, wherein the first exceptional pool or the second exceptional pool is selected based on quality of service (QoS) of a packet to be transmitted.

Referring to an example of this disclosure, a non-transitory computer-readable storage medium may be provided. The non-transitory computer-readable storage medium may store instructions that, when executed, cause a first apparatus to: receive system information including configuration information related to exceptional pools from a base station, wherein the exceptional pools includes a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource; select the first exceptional pool or the second exceptional pool, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable; select a resource from the selected exceptional pool; and perform a sidelink (SL) communication using the resource, wherein the first exceptional pool or the second exceptional pool is selected based on quality of service (QoS) of a packet to be transmitted.

<FIG> shows a procedure of configuring exceptional pools by a base station.

Referring to <FIG>, in step S1610, a base station may transmit system information including configuration information related to exceptional pools to a first apparatus, wherein the exceptional pools includes a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource. For example, the first exceptional pool or the second exceptional pool may be selected, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable. For example, a resource from the first exceptional pool may be selected. For example, a sidelink (SL) communication may be performed using the resource. For example, the first exceptional pool or the second exceptional pool may be selected based on quality of service (QoS) of a packet to be transmitted.

Additionally, for example, the base station may receive a request for a configuration related to an exceptional pool from the first apparatus, wherein the configuration information may be transmitted based on the request.

Examples described above may be applied to variable devices which will be described below. For example, a processor (<NUM>) of a base station (<NUM>) may control a transceiver (<NUM>) to transmit system information including configuration information related to exceptional pools to a first apparatus (<NUM>).

Referring to an example of this disclosure, a base station for performing wireless communication may be provided. The base station may comprise one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: transmit system information including configuration information related to exceptional pools to a first apparatus, wherein the exceptional pools includes a first exceptional pool including a feedback resource and a second exceptional pool not including the feedback resource; wherein the first exceptional pool or the second exceptional pool is selected, based on at least one of a physical layer problem, a connection re-establishment, a handover, or a normal resource pool which is unavailable, wherein a resource from the first exceptional pool is selected, wherein a sidelink (SL) communication is performed using the resource, and wherein the first exceptional pool or the second exceptional pool is selected based on quality of service (QoS) of a packet to be transmitted.

Additionally, for example, the one or more processors further execute the instructions to: receive a request for a configuration related to an exceptional pool from the first apparatus, wherein the configuration information is transmitted based on the request.

Hereinafter, an apparatus to which various embodiments of the present disclosure can be applied will be described.

<FIG> shows a communication system <NUM>, in accordance with an embodiment of the present disclosure.

Referring to <FIG>, a communication system <NUM> to which various embodiments of the present disclosure are applied includes wireless devices, Base Stations (BSs), and a network. Herein, the wireless devices represent devices performing communication using Radio Access Technology (RAT) (e.g., <NUM> New RAT (NR)) or Long-Term Evolution (LTE)) and may be referred to as communication/radio/<NUM> devices. The wireless devices may include, without being limited to, a robot 100a, vehicles 100b-<NUM> and 100b-<NUM>, an extended Reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an Artificial Intelligence (AI) device/server <NUM>. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. Herein, the vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) device and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). For example, the BSs and the network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS/network node with respect to other wireless devices.

Wireless communication/connections 150a, 150b, or 150c may be established between the wireless devices 100a to 100f/BS <NUM>, or BS 200BS <NUM>. Herein, the wireless communication/connections may be established through various RATs (e.g., <NUM> NR) such as uplink/downlink communication 150a, sidelink communication 150b (or, D2D communication), or inter BS communication (e.g. relay, Integrated Access Backhaul (IAB)). The wireless devices and the BSs/the wireless devices may transmit/ receive radio signals to/from each other through the wireless communication/connections 150a and 150b. For example, the wireless communication/connections 150a and 150b may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.

<FIG> shows wireless devices, in accordance with an embodiment of the present disclosure.

The first wireless device <NUM> may include one or more processors <NUM> and one or more memories <NUM> and additionally further include one or more transceivers <NUM> and/ or one or more antennas <NUM>. Herein, the processor(s) <NUM> and the memory(s) <NUM> may be a part of a communication modem/ circuit/chip designed to implement RAT (e.g., LTE or NR).

The second wireless device <NUM> may include one or more processors <NUM> and one or more memories <NUM> and additionally further include one or more transceivers <NUM> and/ or one or more antennas <NUM>. Herein, the processor(s) <NUM> and the memory(s) <NUM> may be a part of a communication modem/ circuit/chip designed to implement RAT (e.g., LTE or NR).

The one or more transceivers <NUM> and <NUM> may be connected to the one or more antennas <NUM> and <NUM> and the one or more transceivers <NUM> and <NUM> may be configured to transmit and receive user data, control information, and/or radio signals/ channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document, through the one or more antennas <NUM> and <NUM>.

<FIG> shows a signal process circuit for a transmission signal, in accordance with an embodiment of the present disclosure.

<FIG> shows another example of a wireless device, in accordance with an embodiment of the present disclosure.

For example, the control unit <NUM> may control an electric/mechanical operation of the wireless device based on programs/ code/commands/information stored in the memory unit <NUM>.

<FIG> shows a hand-held device, in accordance with an embodiment of the present disclosure. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), or a portable computer (e.g., a notebook). The hand-held device may be referred to as a mobile station (MS), a user terminal (UT), a Mobile Subscriber Station (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or a Wireless Terminal (WT).

Blocks <NUM> to <NUM>/140a to 140c correspond to the blocks <NUM> to <NUM>/<NUM> of <FIG>, respectively.

The communication unit <NUM> may receive radio signals from other wireless devices or the BS and then restore the received radio signals into original information/ signals.

<FIG> shows a vehicle or an autonomous vehicle, in accordance with an embodiment of the present disclosure. The vehicle or autonomous vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned Aerial Vehicle (AV), a ship, etc..

Claim 1:
A method for performing, by a first device, wireless communication, the method comprising:
obtaining (S1210, S1320, S1410) information related to a normal resource pool and information related to one exceptional resource pool;
determining (S1420) to use the one exceptional resource pool, based on occurrence of an exceptional case;
selecting (S1430) a first resource from the one exceptional resource pool;
transmitting, to a second device, sidelink control information, SCI, for scheduling a physical sidelink shared channel, PSSCH, through a physical sidelink control channel, PSCCH, based on the first resource; transmitting (S1230, S1340), to the second device, a medium access control, MAC, protocol data unit, PDU, through the PSSCH, based on the first resource; and
receiving (S1240, S1350) a first hybrid automatic repeat request, HARQ, feedback related to the MAC PDU based on a first HARQ feedback resource included in the one exceptional resource pool,
wherein, the one exceptional resource pool includes at least one HARQ feedback resource, for the MAC PDU in which a HARQ feedback is set to enabled,
wherein the at least one HARQ feedback resource includes the first HARQ feedback resource,
wherein the normal resource pool is used based on the first device being not in an exceptional condition, and
wherein the exceptional resource pool is used based on the first device being in an exceptional condition.