To facilitate coexistence of a first radio access technology (RAT) and a second RAT, methods, apparatuses, and computer program products are provided. An example method of a first wireless device operating based on a RAT includes receiving a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a first set of resources. The example method further includes determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The example method further includes transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

INTRODUCTION

The present disclosure relates generally to communication systems, and more particularly, to sidelink communication based on multiple radio access technologies (RATs).

SUMMARY

In an aspect of the disclosure, a method of wireless communication at a first wireless device operating based on a first radio access technology (RAT) is provided. The method includes receiving a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a first set of resources. The example method further includes determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The example method further includes transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

In another aspect, an aspect of the disclosure, an apparatus for wireless communication at a first wireless device operating based on a first radio access technology (RAT) is provided. The apparatus includes means for receiving a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a first set of resources; means for determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT; and means for transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

In another aspect, an aspect of the disclosure, an apparatus for wireless communication at a first wireless device operating based on a first radio access technology (RAT) is provided. The apparatus includes a memory and at least one processor coupled to the memory. The memory and the at least one processor may be configured to receive a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a first set of resources. The memory and the at least one processor may be further configured to determine whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The memory and the at least one processor may be further configured to transmit a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

In another aspect, a non-transitory computer-readable storage medium for wireless communication at a first wireless device operating based on a first radio access technology (RAT) is provided. The computer-readable storage medium stores computer executable code, the code when executed by a processor may cause the processor to receive a sidelink resource reservation from a second wireless device based on a second RAT. The sidelink resource reservation may be reserving a first set of resources of a sidelink resource pool. The code may further cause the processor to determine whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The code may further cause the processor to transmit a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

DETAILED DESCRIPTION

Some wireless communication may be exchanged directly between wireless devices based on sidelink or a PC5 interface rather than being exchanged between a UE and a base station on an access link or Uu link. An example of sidelink communication includes vehicle-to-everything (V2X) communication. Other examples of sidelink communication include device to device (D2D), Proximity Services (ProSe), etc. In some examples, sidelink communications between different sets of sidelink devices and based on different radio access technologies (RATs) may use overlapping frequency resources, e.g., overlapping channels. Therefore, a transmission based on a first sidelink RAT may use frequency resources that may overlap with transmissions for a second sidelink RAT. In some example, the sidelink communications between the different sets of sidelink devices for the different RATs may collide, e.g., may be transmitted on overlapping time and frequency resources. The colliding sidelink transmissions may negatively impact system performances of the different RATs.

The term “sidelink transmission resources” may refer to radio resources such as frequency and time resources used for sidelink transmission. Sidelink transmission resources may be selected from a pool of resources for sidelink transmissions, which may be referred to as a “sidelink resource pool” that defines subsets of time resources and resource blocks available for various sidelink transmission/receptions. Within the sidelink resource pool, a set of resources may be selected/defined as a “candidate resource set” that includes resources available as candidates of resources to be used for a particular transmission. The term “reserved resources” may refer to radio resources reserved for a transmission, whether reserved by the UE or by other sidelink UEs.

Aspects presented herein enable a sidelink device that operates based on a first sidelink RAT to consider wireless resources that may be used for sidelink communication of a second sidelink RAT when selecting resources for sidelink transmissions to other sidelink devices operating based on the first sidelink RAT. For example, a UE (or other sidelink device) that operates based on NR may exclude, from a candidate resource set, one or more resources that are reserved by an LTE sidelink device. Thus, the NR sidelink device may select a resource for a sidelink transmission that does not overlap with the one or more resources reserved by the LTE sidelink device. It should be noted that the example for the NR and LTE sidelink devices is merely to illustrate the concept. The aspects presented herein may be applied for any combination of a first sidelink RAT and a second sidelink RAT. In some aspects, the sidelink resource reservations may be different for different RATs. Thus, the manner in which the UE of one RAT maintains a candidate resources set for sidelink transmission resources may be different for the two RATs. Aspects presented herein enable, a UE for the first RAT to determine whether to exclude, from a candidate resource set within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. In determining whether to exclude the resources reserved for the second sidelink RAT, a wireless device of the first sidelink RAT may use one or more metrics for the first RAT. For example, the wireless device may apply a reference signal received signal (RSRP) threshold or a priority metric of the first RAT. In some aspects, the sidelink UE may use one or more metrics that are different than the metrics applied for the first RAT. For example, the wireless device of the first sidelink RAT may apply a higher RSRP priority level to the reservation, apply a lower RSRP threshold to the reservation, or use a distance between the sidelink devices to determine whether to exclude the reserved resources of the other sidelink RAT. The wireless device may then transmit a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

As one non-limiting example, the aspects presented herein may be applied by an NR V2X UE to handle resources reserved for LTE V2X transmissions. The aspects presented herein may be similarly applied for other sidelink device and for any combination of a first sidelink RAT and a second sidelink RAT. The NR V2X UE may consider the resources, which are reserved for LTE V2X transmission, as reserved resources in a candidate resource set in the sidelink resource pool that the UE uses to select resources for an NR V2X transmission.

For the NR V2X transmissions, the UE may select sidelink transmission resources that are non-overlapping with the reserved sidelink resources for LTE V2X transmissions to transmit a sidelink communication. In some examples, the UE may treat the LTE sidelink resource reservation as an NR sidelink resource reservation, e.g., applying a similar priority level and/or reference signal received power (RSRP) threshold in order to determine whether to consider the LTE sidelink resources as reserved in a resource pool for NR sidelink. In some examples, the NR V2X UE may treat the LTE sidelink resource reservation as a different NR sidelink reservation, e.g., applying a new mechanism for handling the resource reservation that is different than for other NR sidelink reservations.

The NR V2X UE may apply a priority level based on LTE sidelink, based on NR sidelink, or a new or highest priority level for NR sidelink. The NR V2X UE may measure RSRP for the LTE V2X resource reservation based on a measurement on the LTE V2X physical sidelink control channel (PSCCH) and/or a measurement on the LTE V2X physical sidelink shared channel (PSSCH). In some examples, the NR V2X UE may make the determination of whether to consider the resources as reserved based on a weighted combination of the measurements on the PSCCH and the PSSCH. In some examples, the NR V2X UE may apply scaling to the RSRP measurement for the LTE sidelink resource reservation before comparing the RSRP measurement to a threshold for NR sidelink resource management.

In some examples, the NR V2X UE may consider, as reserved, an expanded set of frequency resources for the LTE sidelink resource reservation, e.g., up to the whole bandwidth of the sidelink resource pool.

FIG.1is a diagram illustrating an example of a wireless communications system and an access network100. Some wireless communication networks may include sidelink communication, such as V2X, D2D, ProSe, or other sidelink communication.

Vehicle-based communication devices may include communication from vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes such as a Road Side Unit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as a base station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and/or a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications.

Referring again toFIG.1, in certain aspects, a UE104, e.g., a transmitting Vehicle User Equipment (VUE) or other UE, may be configured to transmit messages directly to another UE104. The communication may be based on V2X or other D2D communication, such as Proximity Services (ProSe), etc. Communication based on V2X and/or D2D may also be transmitted and received by other transmitting and receiving devices, such as Road Side Unit (RSU)107, etc. Aspects of the communication may be based on PC5 or sidelink communication e.g., as described in connection with the example inFIG.2. Although the following description may provide examples for V2X/D2D communication in connection with 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

A UE104, Road Side Unit (RSU)107, or other sidelink device may include a resource reserving component198configured to receive a sidelink resource reservation from a second wireless device based on a second RAT. The sidelink resource reservation indicating a first set of resources of a sidelink resource pool. The resource reserving component198may be further configured to determine whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The resource reserving component198may be further configured to transmit a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations102, UEs104, an Evolved Packet Core (EPC)160, and a Core Network (e.g., 5GC)190. The base stations102may include macro cells (high power cellular base station) and/or small cells (low power cellular base station). The macro cells include base stations. The small cells include femtocells, picocells, and microcells.

Devices may use beamforming to transmit and receive communication. For example,FIG.1illustrates that a base station180may transmit a beamformed signal to the UE104in one or more transmit directions182′. The UE104may receive the beamformed signal from the base station180in one or more receive directions182″. The UE104may also transmit a beamformed signal to the base station180in one or more transmit directions. The base station180may receive the beamformed signal from the UE104in one or more receive directions. The base station180/UE104may perform beam training to determine the best receive and transmit directions for each of the base station180/UE104. The transmit and receive directions for the base station180may or may not be the same. The transmit and receive directions for the UE104may or may not be the same. Although beamformed signals are illustrated between UE104and base station102/180, aspects of beamforming may similarly may be applied by UE104or RSU107to communicate with another UE104or RSU107, such as based on V2X, V2V, or D2D communication.

FIG.2illustrates example diagrams200and210illustrating examples slot structures that may be used for wireless communication between UE104and UE104′, e.g., for sidelink communication. The slot structure may be within a 5G/NR frame structure. Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. This is merely one example, and other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. Diagram200illustrates a single slot transmission, e.g., which may correspond to a 0.5 ms transmission time interval (TTI). Diagram210illustrates an example two-slot aggregation, e.g., an aggregation of two 0.5 ms TTIs. Diagram200illustrates a single RB, whereas diagram210illustrates N RBs. In diagram210, 10 RBs being used for control is merely one example. The number of RBs may differ.

A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. As illustrated inFIG.2, some of the REs may comprise control information, e.g., along with demodulation RS (DMRS).FIG.2also illustrates that symbol(s) may comprise CSI-RS. The symbols inFIG.2that are indicated for DMRS or CSI-RS indicate that the symbol comprises DMRS or CSI-RS REs. Such symbols may also comprise REs that include data. For example, if a number of ports for DMRS or CSI-RS is 1 and a comb-2 pattern is used for DMRS/CSI-RS, then half of the REs may comprise the RS and the other half of the REs may comprise data. A CSI-RS resource may start at any symbol of a slot, and may occupy 1, 2, or 4 symbols depending on a configured number of ports. CSI-RS can be periodic, semi-persistent, or aperiodic (e.g., based on control information triggering). For time/frequency tracking, CSI-RS may be either periodic or aperiodic. CSI-RS may be transmitted in bursts of two or four symbols that are spread across one or two slots. The control information may comprise Sidelink Control Information (SCI). At least one symbol may be used for feedback, as described herein. A symbol prior to and/or after the feedback may be used for turnaround between reception of data and transmission of the feedback. Although symbol 12 is illustrated for data, it may instead be a gap symbol to enable turnaround for feedback in symbol 13. Another symbol, e.g., at the end of the slot may be used as a gap. The gap enables a device to switch from operating as a transmitting device to prepare to operate as a receiving device, e.g., in the following slot. Data may be transmitted in the remaining REs, as illustrated. The data may comprise the data message described herein. The position of any of the SCI, feedback, and LBT symbols may be different than the example illustrated inFIG.2. Multiple slots may be aggregated together.FIG.2also illustrates an example aggregation of two slot. The aggregated number of slots may also be larger than two. When slots are aggregated, the symbols used for feedback and/or a gap symbol may be different that for a single slot. While feedback is not illustrated for the aggregated example, symbol(s) in a multiple slot aggregation may also be allocated for feedback, as illustrated in the one slot example.

FIG.3is a block diagram300of a first wireless communication device310in communication with a second wireless communication device350. In some examples, the devices310and350may communicate based on V2X or other D2D communication. The communication may be based, e.g., on sidelink using a PC5 interface. The devices310and the350may comprise a UE, an RSU, a base station, etc. Packets may be provided to a controller/processor375that implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.

The controller/processor359can be associated with a memory360that stores program codes and data. The memory360may be referred to as a computer-readable medium. The controller/processor359may provide demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing. The controller/processor359is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

The controller/processor375can be associated with a memory376that stores program codes and data. The memory376may be referred to as a computer-readable medium. The controller/processor375provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing. The controller/processor375is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor368, the RX processor356, and the controller/processor359may be configured to perform aspects in connection with resource reserving component198ofFIG.1.

In some wireless communication environments, sidelink communication based on multiple RATs may use overlapping frequency resources, e.g., overlapping channels. The transmissions based on one RAT may collide, e.g., overlap in time and frequency, with the transmission based on the other RAT. The collision may reduce the sidelink performance of both RATs.

FIG.4illustrates an example400of sidelink communication between devices. The communication may be based on a slot structure comprising aspects described in connection withFIG.2. For example, transmitting UE402may transmit a transmission414, e.g., comprising a control channel and/or a corresponding data channel, that may be received by receiving UE404. A control channel may include information for decoding a data channel and may also be used by receiving device to avoid interference by refraining from transmitting on the occupied resources during a data transmission. The number of TTIs, as well as the RBs that will be occupied by the data transmission, may be indicated in a control message from the transmitting device. AlthoughFIG.4illustrates a wireless signal425between the UE402and the UE404, the transmission414may be a unicast sidelink transmission between the UE402and the UE404, a multicast sidelink transmission from the UE402to multiple UEs, or a broadcast transmission for reception by any UE within a transmission range. The UEs402,404,406,408may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, UEs406,408are illustrated as transmitting transmissions416,420. Additionally, or alternatively, RSU407may receive communication from and/or transmit communication418to one or more UEs402,404,406,408. As the UEs may autonomously select time and frequency resources for sidelink transmissions, the UE402and/or404may employ a sensing and reservation procedure to identify resources that are reserved by other UEs as a part of selecting time and frequency resources for a sidelink transmission. As well, different UEs may operate based on different RATs. Some UEs of402,404,406,408or RSU407may include a resource reserving component198, as described in connection withFIG.1that enables the UE to receive sidelink resource reservations for one RAT and to determine whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The UE may transmit a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

For example, the UEs402and404may exchange sidelink communication, such as LTE (e.g., LTE V2X, LTE D2D, etc.) and the UEs406and408may exchange sidelink communication based on a second RAT, such as NR (e.g., NR V2X, NR D2D, etc.). Although the example may be described for LTE V2X and NR V2X to illustrate the concept, the aspects presented herein may be applied to other sidelink communication based on LTE and NR and may also be applied to other sidelink communication including RATs that are different than NR and LTE.

LTE V2X includes PSCCH and PSSCH that are frequency division multiplexed (FDM) in a same subframe. Discrete Fourier Transform (DFT) OFDM waveform may be used with 15 Kilo-Hertz (kHz) subcarrier spacing (SCS). Separate DFT precode and reference signals (RS) may be used for PSSCH and PSCCH. As illustrated in example500inFIG.5A, PSCCH502and PSSCH504might not be adjacent in frequency. In some aspects, the two PRBs may be allocated to the LTE PSCCH502. Sub-channel size may be {5, 6, 10, 15, 20, 25, 50, 75, 100} PRBs for adjacent PSCCH and PSSCH and {4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 30, 48, 72, 96} PRBs for non-adjacent PSCCH and PSSCH. Reservation of resource may be periodic with up to two retransmissions in a period with period values [20, 50], 100, 200, . . . , 1000 milliseconds (ms) with no feedback. reference signal received power (RSRP) for resource selection may be measured on PSSCH DMRS.

For NR V2X, as illustrated in example550inFIG.5B, PSCCH512and PSSCH514are FDMed and time division multiplexed (TDM) in a same subframe. Cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform may be used with [15], 30, [60] kHz SCS. Separate RS may be used for PSCCH512and PSSCH514. 10, 12, 15, 20, or 25 PRBs and 2 or 3 OFDM symbols may be allocated for the PSCCH512. Sub-channel size may be {10, 15, 20, 25, 50, 75, 100} PRBs. Reservations may be aperiodic or periodic with up to 32 retransmissions with period values 1 to 100, 200, . . . , 1000 ms. Feedback on PSFCH may be optionally enabled. RSRP for resource selection is measured on PSCCH or PSSCH DMRS.

Even though the configurations for NR V2X transmissions for UEs406and408and LTE V2X transmissions for UEs402and404are different, the transmissions may be based on overlapping time and frequency resources leading to collisions between NR V2X transmissions and LTE V2X transmissions. The UEs402and404may reserve resources for the LTE V2X transmissions that overlap with the resources for the NR V2X transmissions. Such collision may adversely impact the performance of both the NR V2X transmissions and LTE V2X transmissions. To mitigate the collision issue, methods, apparatuses, and computer program products are presented herein to facilitate coexistence of sidelink communication for multiple RATs using overlapping transmission resources.

The term “sidelink transmission resources” may refer to radio resources such as frequency and time resources used for sidelink transmission. Sidelink transmission resources may be defined and included in a sidelink resource pool that defines subsets of time resources and resource blocks available for various sidelink transmission/receptions. The term “reserved resources” may refer to radio resources reserved for a transmission. The reservation may be indicated to other devices in sidelink control information, for example. Wireless devices may monitor for reservations from other sidelink devices and may avoid using resources overlapping with the reserved resources in transmissions when selecting sidelink transmission resources.

FIG.6illustrates an example communication flow600between wireless devices. As illustrated inFIG.6, a first wireless device (such as a UE)602operating on a first RAT (e.g., NR V2X) receives a sidelink resource reservation608based on a second RAT (e.g., LTE V2X) from a second wireless device (such as a UE)604. The first wireless device602may be configured to decode the sidelink resource reservation608of the other RAT, at610. In some aspects, the first wireless device602may treat the sidelink resource reservation608of the second RAT as a periodic reservation for the first RAT. For example, an NR sidelink device may treat an LTE sidelink reservation as an NR resource reservation. In some aspects, the first wireless device602may treat the sidelink resource reservation608of the other RAT as a special sidelink periodic reservation. For example, an NR sidelink device may treat an LTE sidelink reservation as an NR periodic resource reservation that is handled differently than other NR periodic resource reservations.

After decoding the sidelink resource reservation608, the first wireless device602may consider sidelink transmission resources as reserved, at612, to avoid collision between sidelink transmissions of the first RAT and sidelink transmissions of the second RAT. The sidelink transmission resources that overlap with the sidelink transmission resources considered as reserved may be excluded from further sidelink transmissions, such as described in connection withFIGS.7A and7B. In some aspects, the first wireless device602may use sidelink transmission resources that are non-overlapping with the sidelink transmission resources that are considered as reserved. In some aspects, the first wireless device602may avoid using sidelink transmission resources that overlap with the sidelink transmission resources that are considered as reserved. In some examples, the first wireless device602may exclude the resources that overlap with the sidelink transmission resources that are considered as reserved from candidate resources in a resource pool when selecting resources for a sidelink transmission. The first wireless device602may determine to consider the sidelink transmission resources as reserved resources based on a ProSe per packet priority (PPPP) level. The PPPP level may be based on PPPP for the first RAT (e.g. a PPPP for LTE sidelink), a configured PPPP for the second RAT (e.g., a PPPP for NR sidelink), or a highest PPPP for the second RAT (e.g., a highest PPPP for NR sidelink).

In some aspects, the first wireless device602may determine whether to consider the sidelink transmission resources as reserved resources, at612, based on one or more metrics including comparing a measured RSRP for the sidelink resource reservation608of the first RAT to a reference signal received power (RSRP) threshold. The RSRP may be measured different between the two RATs and/or may be applied differently between the two RATs. In some aspects, the RSRP threshold may be a function of the PPPP of a transmission packet and the PPPP of the reservation.

For example, in LTE, the RSRP for a sidelink resource reservation may be measured based on PSSCH DMRS. As well, there may be a different power spectral density (PSD) between the RBs comprising the PSSCH and the RBs comprising the PSCCH for an LTE V2X resource reservation. In contrast, an NR V2X UE may measure the RSRP of the resource reservation differently, e.g., PSSCH DMRS, or PSCCH DMRS.

In some aspects, the first wireless device602inFIG.6may measure the RSRP of the sidelink resource reservation608for the second RAT based on a PSCCH DMRS, a PSSCH DMRS, or a combination of both the PSCCH DMRS and the PSSCH DMRS. For example, the first wireless device602(as an NR sidelink device) may determine the RSRP based on a weighted average, of the LTE PSCCH DMRS and the LTE PSSCH DMRS.

Additionally, or alternatively, the first wireless device602may apply a scaling factor before determining whether the RSRP of the LTE sidelink resource reservation608meets the threshold. By applying a scaling factor before determining whether the RSRP of the LTE sidelink resource reservation608meets the threshold, the first wireless device602may take into account differences in NR and LTE sidelink transmission bandwidth and power spectral density (PSD). For example, there may be a 3 decibel PSD difference between RBs containing PSSCH and RBs containing PSCCH for LTE V2X transmissions. In some examples, in order to refrain from scaling, the UE may apply a scaling factor of 1.

At612, the first wireless device602considers the sidelink transmission resources for sidelink transmission for the first RAT (e.g., an NR sidelink resource pool) as reserved resources based on the sidelink resource reservation608for the second RAT. In some aspects, the first wireless device602may consider, as reserved, expanded frequency resources based on the sidelink resource reservation608, e.g., beyond the specific frequency resources reserved by the UE604. For example, the first wireless device602may consider, as reserved, a whole bandwidth that includes resources reserved by the sidelink resource reservation608.

In some aspects, a PPPP may be defined for sidelink reservations of the second RAT and used by the first wireless device602to determine whether to consider, as reserved, the sidelink resources for the first RAT. In some aspects, the PPPP may correspond to a smallest or a minus infinite decibel milliwatt RSRP threshold for sidelink reservations so that radio resources reserved for the second RAT are considered as reserved by the first wireless device602if the first wireless device602decodes the PSCCH that includes the reservation608. The first wireless device may consider, as reserved, the resources without an RSRP measurement if the PSCCH is decoded. In some aspects, the first wireless device602may use distance based consideration based on a distance between the first wireless device602and the UE604. For example, the first wireless device602may consider the sidelink resources in the reservation608as reserved resources if the distance between the first wireless device602and the UE604is within a range. The first wireless device602may decode basic safety messages (BSM) from the UE604containing location information and may use the location information to determine the distance between the first wireless device602and the UE604for the distance based consideration. A distance based consideration may be more robust against blocking and non-line of sight (NLOS) conditions.

After considering sidelink transmission resources as reserved based on the sidelink resource reservation608, the first wireless device602may select sidelink transmission resources that do not overlap with the resources that are considered as reserved and use the selected resources for sidelink transmission614(e.g., an NR sidelink transmission such as NR V2X) between the first wireless device602and a third wireless device606operating based on the second RAT. For example, the wireless device may exclude the resources that are considered as reserved from candidate resources when selecting sidelink resources for transmission based on the first RAT.

As illustrated in example700ofFIG.7A, a wireless device operating based on a first RAT, such as the first wireless device602described in connection withFIG.6, may receive a resource reservation indicating sidelink transmission resources704from a wireless device operating based on a second RAT, such as the second wireless device604described in connection withFIG.6. The wireless device may consider the sidelink transmission resources704as reserved based on the resource reservation from the wireless device operating based on a second RAT and may exclude, from a candidate set of sidelink resources702for the first RAT, at least one or more candidate resources that overlap with the sidelink transmission resources reserved for the sidelink transmissions of the second sidelink RAT. In some aspects, a lower layer of the wireless device may determine a subset of resources from which a higher layer may select resources for PSSCH/PSCCH transmissions from the wireless device. The wireless device may exclude candidate resources that meet conditions, such as reception of an SCI from another device indicating a resource reservation for the same sidelink RAT and having an RSRP measurement that meets a threshold. As presented herein, the wireless device may determine to further exclude at least one or more candidate resources from the subset of candidate resources that overlap with the sidelink transmission resources reserved for sidelink transmissions of a different RAT. As with the resources reserved for sidelink transmissions of the same RAT, the UE may determine if one or more conditions are met in order to determine whether to consider the reserved resources for the second RAT sidelink transmission as being reserved resources for resource selection of sidelink resources for the first RAT. If the sidelink transmission resources704for the second RAT includes a set of slots numbered 24-32, the set of slots numbered 24-32 may be considered as reserved (which may also be referred to as being marked, marked as reserved, or marked as reserved by an interferer) for purposes of resource selection for the first sidelink RAT. The wireless device may exclude the set of slots numbered 24-32 from the candidate resource set for resource selection for the first sidelink RAT and may refrain from utilizing resources that overlap with the set of slots numbered 24-32 when selecting resources for transmitting PSSCH/PSCCH based on the first RAT. The wireless device may exclude additional resources beyond the specific overlapping resources. The wireless device may refrain from selecting resources that overlap, at least partially, with the resources reserved for the second sidelink RAT transmission, as illustrated inFIG.7B.FIG.7Billustrates that RB 0-50 are reserved for the second sidelink transmission706. For example, the wireless device may refrain from utilizing a set of resources that includes RBs in the same slot that partially or fully overlap the reserved resources for the second sidelink RAT, e.g., as illustrated at708. The wireless device may also refrain from utilizing a set of resources that partially overlaps the resources reserved for the second sidelink RAT, e.g., RB numbered 40-80, e.g., as illustrated at710.

FIG.8is a flowchart800of a method of wireless communication. method may be performed by a wireless device (e.g., the UE104, the UE408, the wireless device602, the apparatus902) operating based on a first RAT, such as NR. Optional aspects are illustrated with a dashed line. The method enables the wireless device to help to avoid collisions with sidelink transmissions of a different RAT.

At802, the wireless device receives a sidelink resource reservation from a second wireless device based on a second RAT. The sidelink resource reservation indicating indicating a set of reserved resources. For example, reception802may be performed by sidelink resource reservation reception component942ofFIG.9. The reception802may include aspects described in connection with LTE sidelink resource reservation608ofFIG.6. In some aspects, the first RAT includes NR sidelink communication and the second RAT includes LTE sidelink communication.

At804, the wireless device determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. In some aspects, the wireless device may exclude resources that overlap with the first set of reserved resources for the second RAT from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, as illustrated at806. For example, the wireless device may exclude one or more resources that are at least partially overlapping with the first set of reserved resources. The determination at804may be performed by sidelink transmission resource determination component944ofFIG.9. The determination804may include aspects described in connection with610and612ofFIG.6.

In some aspects, the first wireless device determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT using one or more metrics for a periodic sidelink resource reservation for the first RAT, as illustrated at812. In some aspects, the one or more metrics includes a RSRP threshold for the periodic sidelink resource reservation for the first RAT, as illustrated at814. In some aspects, the one or more metrics includes a priority metric for the periodic sidelink resource reservation for the first RAT as illustrated at816. In some aspects, the first wireless device determines a priority of the set of reserved resources for the first RAT based on a PPPP level for sidelink communication based on the second RAT, a configured PPPP for the sidelink communication based on the first RAT, or a highest PPPP level for the sidelink communication based on the first RAT. The RSRP threshold may be determined based on the PPPP. In some aspects, the first wireless device determines an RSRP of the set of reserved resources of the first RAT based on an RSRP measurement for one or more of a PSSCH of the sidelink resource reservation from the second wireless device or a PSCCH of the sidelink resource reservation from the second wireless device. For example, the wireless device may use the measured RSRP to determine whether to exclude the first set of reserved resources from the candidate resources set of the first RAT, as illustrated at826.

In some aspects, the first wireless device determines the RSRP of the set of resources based on a combination of a first RSRP measurement of the PSCCH and a second RSRP measurement of the PSSCH. In some aspects, as part of804, the wireless device determines, at828, a combined RSRP measurement based on a weighted average of the first RSRP measurement and the second RSRP measurement. In some aspects, as part of804, the wireless device applies, at830, a scaling factor to the RSRP. The scaling factor may be 1 in some aspects. In some aspects, wireless device may exclude an expanded set of frequency resources for the sidelink resource reservation.

In some aspects, the first wireless device determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT using one or more metrics, that are different than a set of metrics that the first wireless device applies for sidelink resource reservations of the first RAT, as illustrated at818. In some aspects, the one or more metrics may include a higher priority level for the sidelink resource reservation based on the second RAT than for sidelink resource reservations based on the first RAT, as illustrated at820.

In some aspects, the one or more metrics includes a lower RSRP threshold for the sidelink resource reservation based on the second RAT than for sidelink resource reservations based on the first RAT, as illustrated at822. In some aspects, the lower RSRP threshold may include a minus infinite RSRP threshold. In some aspects, the first wireless device determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT using a distance between the first wireless device and the second wireless device, as illustrated at824. In some aspects, the first wireless device determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT based on a measured RSRP, as illustrated at826.

At810, the wireless device transmits a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT. In some aspects, the wireless device may not select sidelink transmission resources that overlaps with the resources that are considered as reserved, such as illustrated at808. For example, transmission810may be performed by RAT transmission component946ofFIG.9. The transmission810may include aspects described in connection with610,612, and614ofFIG.6. In some aspects, the first wireless device excludes an expanded set of frequency resources based on the sidelink resources reservation, as illustrated at808. For example, the wireless device may exclude a full bandwidth of the sidelink resource pool during time resources reserved by the sidelink resource reservation.

FIG.9is a diagram900illustrating an example of a hardware implementation for an apparatus902. The apparatus902is a wireless device and includes a baseband unit904. The baseband unit904may communicate through a cellular RF transceiver with the UE104. The baseband unit904may include a computer-readable medium/memory. The baseband unit904is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the baseband unit904, causes the baseband unit904to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the baseband unit904when executing software. The baseband unit904further includes a reception component930, a communication manager932, and a transmission component934. The communication manager932includes the one or more illustrated components. The components within the communication manager932may be stored in the computer-readable medium/memory and/or configured as hardware within the baseband unit904. The baseband unit904may be a component of the device310/450and may include the memory360/376and/or at least one of the TX processor316/368, the RX processor356/370, and the controller/processor359/375.

The communication manager932includes a sidelink resource reservation reception component942that receives a sidelink resource reservation from a second wireless device based on a second RAT, e.g., as described in connection with reception802ofFIG.8.

The communication manager932further includes a sidelink transmission resource determination component944that determines whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT, e.g., as described in connection with determination804ofFIG.8.

The communication manager932further includes a RAT transmission component946that transmits a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT, e.g., as described in connection with transmission810ofFIG.8.

In one configuration, the apparatus902, and in particular the baseband unit904, includes means for receiving a sidelink resource reservation from a second wireless device based on a second RAT (e.g., the sidelink resource reservation reception component942of the communication manager932comprised in the baseband unit904and/or a transceiver). The baseband unit904further includes means for determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT (e.g., the RAT transmission component946of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for excluding the resources that overlap with the set of reserved resources for the second RAT from the candidate resource set for the first RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for using one or more metrics for the sidelink resource reservation for the first RAT to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT within the sidelink resource pool for the first RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for determining an RSRP of the set of reserved resources of the first RAT based on an RSRP measurement (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for determining a combined RSRP measurement based on a weighted average of the first RSRP measurement and the second RSRP measurement (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for applying a scaling factor to the RSRP (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for using a measured reference signal received power (RSRP) to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for using one or more metrics that are different than the first wireless device applies for sidelink resource reservations of the first RAT to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for excluding an expanded set of frequency resources based on the sidelink resource reservation (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904). The baseband unit904further includes means for using a distance between the first wireless device and the second wireless device to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT (e.g., the sidelink transmission resource determination component944of the communication manager932comprised in the baseband unit904).

The aforementioned means may be one or more of the aforementioned components of the apparatus902configured to perform the functions recited by the aforementioned means. As described supra, the apparatus902may include the TX processor316/368, the RX processor356/370, and the controller/processor359/375. As such, in one configuration, the aforementioned means may be the TX processor316/368, the RX processor356/370, and the controller/processor359/375configured to perform the functions recited by the aforementioned means.

The following aspects are illustrative only and may be combined with aspects of other embodiments or teachings described herein, without limitation.

Aspect 1 is a method of wireless communication at a first wireless device operating based on a first RAT, including: receiving a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a set of reserved resources; determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT; and transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

Aspect 2 is the method of aspect 1, further including: using one or more metrics for the sidelink resource reservation for the first RAT to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT within the sidelink resource pool for the first RAT.

Aspect 3 is the method of any of aspects 1-2, further including: excluding the resources that overlap with the set of reserved resources for the second RAT from the candidate resource set for the first RAT, where the first wireless device transmits the sidelink transmission using the one or more sidelink transmission resources in the sidelink resource pool for the first RAT that are non-overlapping with the set of reserved resources.

Aspect 4 is the method of any of aspects 1-3, where the first wireless device excludes, from the candidate resource set for the first RAT, the resources that partially overlap with the set of reserved resources for the second RAT.

Aspect 5 is the method of any of aspects 1-4, where the first RAT includes NR sidelink communication and the second RAT includes LTE sidelink communication.

Aspect 6 is the method of any of aspects 1-5, where the NR sidelink communication comprises NR V2X communication and the LTE sidelink communication comprises LTE V2X communication.

Aspect 7 is the method of any of aspects 1-6, where the one or more metrics are for a periodic sidelink resource reservation.

Aspect 8 is the method of any of aspects 1-7, where the one or more metrics includes a priority of the set of reserved resources for the first RAT based on at least one of: a PPPP level for sidelink communication based on the second RAT, a configured PPPP for the sidelink communication based on the first RAT, or a highest PPPP level for the sidelink communication based on the first RAT.

Aspect 9 is the method of any of aspects 1-8, where the one or more metrics includes at least one of a RSRP threshold or a priority metric for the sidelink resource reservation for the first RAT.

Aspect 10 is the method of any of aspects 1-9, where the RSRP threshold or the priority metric is for a periodic sidelink reservation for the first RAT.

Aspect 11 is the method of any of aspects 1-10, further including: determining an RSRP of the set of reserved resources of the first RAT based on an RSRP measurement for one or more of: a PSSCH of the sidelink resource reservation from the second wireless device, or a PSCCH of the sidelink resource reservation from the second wireless device.

Aspect 12 is the method of any of aspects 1-11, where the first wireless device determines the RSRP of the set of reserved resources based on a combination of a first RSRP measurement of the PSCCH and a second RSRP measurement of the PSSCH.

Aspect 13 is the method of any of aspects 1-12, further including: determining a combined RSRP measurement based on a weighted average of the first RSRP measurement and the second RSRP measurement.

Aspect 14 is the method of any of aspects 1-13, further including: applying a scaling factor to the RSRP.

Aspect 15 is the method of any of aspects 1-14, further including: using a measured RSRP to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT.

Aspect 16 is the method of any of aspects 1-15, further including: using one or more metrics, that are different than a set of metrics that the first wireless device applies for sidelink resource reservations of the first RAT, from the candidate resource set for the first RAT.

Aspect 17 is the method of any of aspects 1-16, where the one or more metrics includes a higher priority level for the sidelink resource reservation based on the second RAT than for the sidelink resource reservations based on the first RAT.

Aspect 18 is the method of any of aspects 1-17, where the one or more metrics includes a lower RSRP threshold for the sidelink resource reservation based on the second RAT than for the sidelink resource reservations based on the first RAT.

Aspect 19 is the method of any of aspects 1-18, where the lower RSRP threshold comprises a minus infinite RSRP threshold.

Aspect 20 is the method of any of aspects 1-19, further including: excluding an expanded set of frequency resources based on the sidelink resource reservation.

Aspect 21 is the method of any of aspects 1-20, where the first wireless device excludes a full bandwidth of the sidelink resource pool during time resources reserved by the sidelink resource reservation.

Aspect 22 is the method of any of aspects 1-21, further including: using a distance between the first wireless device and the second wireless device to determine whether to exclude the set of reserved resources for the second RAT from the candidate resource set for the first RAT.

Aspect 23 is an apparatus for wireless communication of a first wireless device operating based on a first RAT. The apparatus includes a memory and at least one processor coupled to the memory and configured to perform the methods of any of examples 1-22.

Aspect 24 is an apparatus for wireless communication of a first wireless device operating based on a first RAT. The apparatus includes means for performing the methods of any of examples 1-22.

Aspect 25 is a computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to perform the methods of any of examples 1-22.