Patent Description:
For example, some aspects of wireless communication include direct communication between devices, such as device-to-device (D2D), vehicle-to-anything (V2X), and the like. There exists a need for further improvements in such direct communication between devices. Improvements related to direct communication between devices may be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. Document <CIT> relates to a method being performed by a base station, which includes: configuring a first resource pool, with the first resource pool being used for information transmission of a first type of UE in a sidelink transmission mode, where the first type of UE carries out a sidelink transmission by base station scheduling, configuring a second resource pool, with the second resource pool being used for information transmission of a second type of UE in a sidelink transmission mode, where the second type of UE autonomously carries out the sidelink transmission, and the first resource pool and the second resource pool are orthogonal to each other. Document <NPL>, discusses achievable latency performance with long-term TDM, which coexistence scenarios are feasible for short-term time-scale TDM, and benefits of network assistance message for coexistence between LTE V2X and NR V2X. Document <NPL>, concerns radio solutions that are necessary for NR to support sidelink and enable several aspects of advanced V2X services.

In some wireless communications environments, a transmitting device, such as a user equipment (UE), and a receiving device, such as another UE, may communicate using multiple packets that are transmitted over the air. The transmitting device may transmit each of the packets multiple times in order to reserve a set of resources. For example, the transmitting device may transmit a transmission reserving resources for a first transmission, the first transmission of the packet may reserve resources for the next transmission of the packet, and so forth.

When other devices, such as other UEs, receive transmissions reserving resources, the other devices may refrain from transmitting on the reserved resources reserved. For example, the other UEs may back off or delay transmitting on resources for the duration of the reservation. By refraining from transmitting on reserved resources, interference experienced by receiving devices can be reduced.

In some aspects, a transmitting device may retransmit a packet if an intended receiver did not correctly receive the packet. For example, if an intended receiver responds with a non-acknowledgement (NACK), the transmitting device may determine to retransmit the packet. However, if the transmitting device does not receive a NACK from any of the intended receivers, the transmitting device may determine that a retransmission of the packet is not needed and may refrain from retransmitting the packet.

Potentially, other devices that avoid transmitting on resources reserved by the transmitting device may also monitor for a NACK from the intended receiver(s) of the transmitting device. If one of the other devices detects a NACK from an intended receiver of the transmitting device, the one of the other devices may avoid using the resources reserved for the retransmission. However, if a NACK from the intended receiver(s) of the transmitting device is not detected, the one of the other devices may determine that the reserved resources will not be used by the transmitting device for a retransmission, and therefore, the one of the other devices may use the reserved resources to transmit communication.

In some situations, the reservation of resources may not fully avoid collisions between transmissions. For example, two devices may reserve resources at the same time. One or both of the two devices may be unaware of the other reservation and may transmit in an overlapping manner that interferes with the transmission of the other device. For example, one transmitting device may be a hidden node for the other device and therefore may be an interfering device. The interfering device may be outside of a link budget range of the control transmissions for the other transmitting device when the other transmitting device transmits a reservation, but the interfering device may still transmit with a power sufficient to disrupt reception at an intended receiver(s).

The present disclosure describes various techniques and approaches to reduce the amount and/or mitigate the effects of interfering transmissions based on identifying overlapping reservations between two transmitting devices. Various aspects described herein enable receiving devices to determine which of two or more potentially colliding transmissions should proceed (and by extension, which of the two or more potentially colliding transmissions should be backed off). In some aspects, if multiple receiving devices are affected by a potential collision, each of the receiving devices may identify the same transmitting device that should be informed about the collision, such as by applying a global rule.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations <NUM>, user equipment(s) (UE) <NUM>, an Evolved Packet Core (EPC) <NUM>, and another core network <NUM> (e.g., a <NUM> Core (5GC)).

The base stations <NUM> configured for <NUM> Long Term Evolution (LTE) (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through first backhaul links <NUM> (e.g., S1 interface). The base stations <NUM> configured for <NUM> New Radio (NR) (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network <NUM> through second backhaul links <NUM>.

The base stations <NUM> / UEs <NUM> may use spectrum up to Y megahertz (MHz) (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction.

The wireless communications system may further include a Wi-Fi access point (AP) <NUM> in communication with Wi-Fi stations (STAs) <NUM> via communication links <NUM>, e.g., in a <NUM> gigahertz (GHz) unlicensed frequency spectrum or the like.

Generally, the AMF <NUM> provides Quality of Service (QoS) flow and session management.

Although the present disclosure may focus on <NUM> NR, the concepts and various aspects described herein may be applicable to other similar areas, such as LTE, LTE-Advanced (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile communications (GSM), or other wireless/radio access technologies.

Further, although the present disclosure may focus on vehicle-to-vehicle (V2V) communication, the concepts and various aspects described herein may be applicable to other similar areas, such as D2D communication, IoT communication, vehicle-to-anything (V2X) communication, or other standards/protocols for communication in wireless/access networks.

Some wireless communication networks may include vehicle-based communication devices that can communicate from 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), and/or a combination thereof and/or with other devices, which can be collectively referred to as V2X communications. Referring again to <FIG>, in certain aspects, a UE <NUM>, e.g., a transmitting Vehicle User Equipment (VUE) or other UE, may be configured to transmit messages directly to another UE <NUM>. The communication may be based on V2V/N2X/V2I or other D2D communication, such as Proximity Services (ProSe), etc. Communication based on V2V, V2X, V2I, and/or other D2D may also be transmitted and received by other transmitting and receiving devices, such as RSU <NUM>, etc. Aspects of the communication may be based on PC5 or sidelink communication, e.g., as described in connection with the example in <FIG>.

Referring again to <FIG>, in certain aspects, a receiving device, such as a UE <NUM> and/or RSU <NUM>, may include a collision feedback component <NUM> configured to identify a collision between first resources reserved by a first transmitting device (e.g., UE <NUM>') and second resources reserved by a second transmitting device (e.g., UE <NUM>"). The collision feedback component <NUM> of the receiving device (e.g., UE <NUM> and/or RSU <NUM>) may then transmit a collision indication to the first transmitting device (e.g., UE <NUM>') or the second transmitting device (e.g., UE <NUM>") based on the identified collision.

In certain other aspects, a transmitting device (e.g., the UE <NUM>' and/or RSU <NUM>) may transmit a resource reservation for a transmission from the transmitting device to at least one receiving device (e.g., the UE <NUM> and/or RSU <NUM>). The transmitting device may include a back off component <NUM> configured to receive a collision indication from one of the at least one receiving device. In response to receiving the collision indication, the back off component <NUM> may configure the transmitting device to back off from transmitting during resources reserved by the resource reservation. Although only the UE <NUM> and RSU <NUM> are illustrated as having a collision feedback component <NUM>, and only the UE <NUM>' and RSU <NUM> are illustrated as having a back off component <NUM>, any UE (and/or any device configured for D2D communication) may include one or more components similar to the collision feedback component <NUM> and/or the back off component <NUM>.

In the examples provided by <FIG>, the <NUM> NR frame structure is assumed to be TDD, with subframe <NUM> being configured with slot format <NUM> (with mostly DL), where D is DL, U is UL, and F is flexible for use between DL/UL, and subframe <NUM> being configured with slot format <NUM> (with mostly UL).

A frame, e.g., of <NUM> milliseconds (ms), may be divided into <NUM> equally sized subframes (<NUM>). The symbols on DL may be cyclic prefix (CP) orthogonal frequency-division multiplexing (OFDM) (CP-OFDM) symbols. For slot configuration <NUM>, different numerologies µ <NUM> to <NUM> allow for <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> slots, respectively, per subframe. The subcarrier spacing may be equal to <NUM>µ * <NUM> kilohertz (kHz), where µ is the numerology <NUM> to <NUM>. <FIG> provide an example of slot configuration <NUM> with <NUM> symbols per slot and numerology µ=<NUM> with <NUM> slots per subframe. The slot duration is <NUM>, the subcarrier spacing is <NUM>, and the symbol duration is approximately <NUM>. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see <FIG>) that are frequency division multiplexed. Each BWP may have a particular numerology.

A PDCCH within one BWP may be referred to as a control resource set (CORESET). Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)/PBCH block (also referred to as SS block (SSB)).

The SRS may be used by a base station for channel quality estimation to enable frequencydependent scheduling on the UL.

The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) / non-acknowledgement (NACK) feedback.

In some aspects, at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> may be configured to perform aspects in connection with <NUM> of <FIG>.

In some other aspects, at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> may be configured to perform aspects in connection with <NUM> of <FIG>.

<FIG> illustrates an example <NUM> of wireless communication between devices based on V2X and/or other D2D communication. The communication may be based on a slot structure including aspects described in connection with <FIG>, supra. For example, a transmitting UE <NUM> may transmit a transmission <NUM>, e.g., including control information and/or data on a control channel and/or a corresponding data channel. The transmission <NUM> may be intended (e.g., addressed) for a set of receiving UEs <NUM>, <NUM>, and <NUM>. 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.

The UEs <NUM>, <NUM>, <NUM>, and <NUM> may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, the UEs <NUM>, <NUM> are illustrated as transmitting the transmissions <NUM> and <NUM>. The transmissions <NUM>, <NUM>, and <NUM> may be broadcast or multicast to nearby devices. For example, the UE <NUM> may transmit communication intended to be received by other UEs within a range <NUM> of the UE <NUM>. In some aspects, a RSC <NUM> may receive communication from and/or transmit communication to one or more of the UEs <NUM>, <NUM>, <NUM>, and <NUM>.

A transmitting device, such as the UE <NUM>, may transmit each packet multiple times. For example, the UE <NUM> may send a transmission reserving resources for a first transmission. The first transmission of the packet may reserve resources for the next transmission of the packet. Other devices, such as the UE <NUM> and <NUM> and the RSC <NUM> may avoid transmitting using the resources reserved by the UE <NUM>. By avoiding the resources reserved for transmission by other devices, the interference experienced by the receiving devices can be reduced.

In some aspects, the transmitting UE <NUM> may retransmit the packet only if an intended receiver did not correctly receive the packet. For example, if the receiving UE <NUM> responds to the transmitting UE <NUM> with a NACK (e.g., based on failing to correctly receive the packet), the transmitting UE <NUM> may determine to retransmit the packet. However, if the UE <NUM> does not receive a NACK from any of the intended receivers, the UE <NUM> may determine that a retransmission of the packet is not needed and may refrain from retransmitting the packet.

Further, other devices that are avoiding transmitting on the reserved resources of the UE <NUM> may also monitor for a NACK from the intended receivers of the UE <NUM>. If another device detects a NACK from an intended receiver of the UE <NUM>, the other device may avoid using the resources reserved for the retransmission. If the other device does not detect a NACK from the intended receiver(s) of the UE <NUM>, the other device may determine that the reserved resources will not be used by the UE <NUM> for a retransmission and the other device may use the reserved resources to transmit communication.

In some situations, the reservation of resources may not fully avoid collisions between transmissions. For example, two devices may reserve resources at the same time. The two devices may not be aware of the other reservation and may transmit in an overlapping manner that interferes with the transmission of the other device. For example, one transmitting device may be a hidden node for the other device. Illustratively, an interfering device may be outside of a link budget range of the control transmissions for the transmitting UE <NUM> when the UE <NUM> transmits a reservation, but the interfering device may still transmit with a sufficiently strong enough transmission to disrupt reception at a receiver. For example, if the UE <NUM> transmits a resource reservation and the UE <NUM> transmits a resource reservation, the two UEs may unaware of the potential collision because the UE <NUM> is outside of the range <NUM> of the UE <NUM>. However, the transmissions from UE <NUM> may collide with the transmissions from the UE <NUM> when received by the UE <NUM>.

<FIG> illustrates a diagram showing an example of a hidden node scenario <NUM>. In <FIG>, device A <NUM> is traveling on a first road and devices B <NUM> and C <NUM> are on a second road. Device B <NUM> may be outside of a protected radius, e.g., an intended range, of device A <NUM>. Therefore, the same time and frequency resources may be used for transmissions by device A <NUM> and device B <NUM>. Device C <NUM> may be an intended receiver for transmissions <NUM> from device A <NUM>. However, the signal from device A <NUM> to device C <NUM> may be weak, because the channel is a non-line of sight (NLOS) channel. In contrast, interference that device B <NUM> experiences due to transmission <NUM> device C <NUM> may be substantial, e.g., because there is a line of sight (LOS) condition for devices B <NUM> and C <NUM>. As a result, device C <NUM> may be unable to correctly receive and decode the transmission <NUM> from device A <NUM>.

Relatedly, <FIG> is a graph showing a comparison for pathloss <NUM> over a distance for NLOS communication and pathloss <NUM> over a distance for LOS communication. Illustratively, if a pathloss of less than <NUM> decibels (dB) is considered acceptable for communication between two devices based on V2X or other D2D communication, in an NLOS situation, the pathloss <NUM> is already at <NUM> dB when a distance of <NUM> meters is reached. In contrast, an LOS condition may not reach a similar level of pathloss <NUM> until a distance of <NUM> meters. In the context of <FIG>, device B <NUM> may interfere with reception of transmission <NUM> by device C <NUM> from device A <NUM> even at a large distance.

The present disclosure provides various techniques and approaches to reducing interfering transmissions based on overlapping reservations between two or more transmitting devices by a receiving device (e.g., UE <NUM> in <FIG>, device C in <FIG>, etc.) sending a collision indication to one of the transmitting devices. In response to receiving the collision indication, one of the transmitting devices may back off from transmitting on the resources indicated by the respective reservation. For example, in <FIG>, the receiving UE <NUM> may send a collision indication to either the transmitting UE <NUM> or the transmitting UE <NUM> to inform that transmitting UE that the resources are reserved, and that transmitting UE is not clear to send (CTS) a transmission on the reserved resources. In <FIG>, for example, the device C <NUM> may end an indication to either device A <NUM> or Device B <NUM> with a such a collision indication.

According to some aspects, a receiving device may determine that a collision between reserved resources will occur if the reserved resources at least partially overlap; that is, the resources reserved by two transmitted devices occur on at least some of the same time/frequency resources. The receiving device may also consider a measurement of the signals from the two transmitting devices. For example, the receiving device may determine a collision if a difference between the measurements for the signals from the two transmitting devices is within a threshold level and/or within a range, such a preconfigured threshold level and/or preconfigured range. The measurements may include, for example, reference signal receive power (RSRP), signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), reference signal receive quality (RSRQ), and/or another similar measurement. In some aspects, the receiving device may base the determination on a distance between the receiving device and each of the transmitting devices (e.g., the distance between device C <NUM> and device A <NUM>, as well as the distance between device C <NUM> and device B <NUM>). In some further aspects, the receiving device may base the determination on a distance between the two transmitting devices (e.g., the distance between device A <NUM> and device B <NUM>).

The receiving device may inform either device A or device B of the potential collision. The transmitting device that receives the indication may back off and refrain from transmitting using the reserved resources. If the receiving device transmitted the collision indication to both transmitting devices, it may lead to a waste of resources because both transmitting devices may back off and avoid using the reserved resources. Additionally, the transmitting devices may attempt to reserve later resources to transmit the message, which may lead to another collision. Therefore, by transmitting a collision indication to one of the transmitting devices, the receiving device facilitates interference reduction while enabling the other transmission to continue.

Aspects presented herein enable receiving devices to determine which of the colliding transmissions should proceed in a uniform manner. Therefore, if there are multiple receiving devices affected by the potential collision, each of the receiving UEs may identify the same transmitting device that should be informed about the collision. Therefore, a global rule may be applied by receiving devices to determine which transmitting device to inform about the collision.

<FIG> is a call flow diagram illustrating an example communication flow <NUM> between a device <NUM> and two transmitting devices <NUM>, <NUM>. Although the device <NUM> may be referred to as a receiving device, the device may be capable of both transmission and reception. Similarly, the transmitting devices <NUM>, <NUM> may operate at times as receiving devices. The receiving device <NUM> may receive resource reservation <NUM> and/or resource reservation <NUM> from the first transmitting device <NUM>, and may further receive another resource reservation <NUM> from the second transmitting device <NUM>.

The receiving device <NUM> may perform an identification <NUM> of a potential collision between the resources reserved by the first and second transmitting devices <NUM>, <NUM> based on at least one of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM> and the resource reservation <NUM> from the second transmitting device <NUM>. In some aspects, the receiving device <NUM> may base such identification <NUM> on an overlap in the time/frequency of the resources scheduled by the first and second transmitting devices <NUM>, <NUM>. For example, the receiving device <NUM> may identify a first set of time/frequency resources included in one of the resource reservations <NUM>, <NUM> and/or may identify a second set of time/frequency resources included in the other of the resource reservations <NUM>, <NUM> received from the first transmitting device <NUM>. Further, the receiving device <NUM> may identify a third set of time/frequency resources included in the resource reservation <NUM> received from the second transmitting device <NUM>. The receiving device <NUM> may then compare the first and/or second sets of time/frequency resources to the third set of time/frequency resources, and the receiving device <NUM> may determine whether the first and/or second sets of time/frequency resources at least partially overlap with the third set of time/frequency resources. The receiving device <NUM> may then make the identification <NUM> of the potential collision when the receiving device <NUM> determines that the first and/or second sets of time/frequency resources at least partially overlap (e.g., in both time and frequency).

Additionally or alternatively, the receiving device <NUM> may base such identification <NUM> on a difference in channel quality values (e.g., RSRPs, SNRs, SINRs, RSRQs, etc.) measured between at least one of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM> and the resource reservation <NUM> from the second transmitting device <NUM>. For example, the receiving device <NUM> may measure a first channel quality value based on receiving one of the resource reservations <NUM>, <NUM> and may measure a second channel quality value based on receiving the other of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM>. The receiving device <NUM> may then measure a third channel quality value based on receiving the resource reservation <NUM> from the second transmitting device <NUM>. The receiving device <NUM> may compare the first and/or second channel quality values to the third channel quality value, e.g., in order to determine a difference. Subsequently, the receiving device <NUM> may compare the difference(s) to a channel quality threshold and/or may determine whether the difference(s) falls within a channel quality range. The receiving device <NUM> may then make the identification <NUM> of the potential collision when the receiving device <NUM> determines that the difference(s) satisfies the channel quality threshold and/or is within the channel quality range.

Additionally or alternatively, the receiving device <NUM> may base such identification on a first distance between the first transmitting device <NUM> and the receiving device <NUM> and a second distance between the second transmitting device <NUM> and the receiving device <NUM>. For example, the receiving device <NUM> may measure a first distance between the receiving device <NUM> and the first transmitting device <NUM> (e.g., based on receiving one of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM>). The receiving device <NUM> may then measure a second distance between the receiving device <NUM> and the second transmitting device (e.g., based on receiving the resource reservation <NUM> from the second transmitting device <NUM>). The receiving device <NUM> may compare the first distance to the second distance, e.g., in order to determine a difference. Subsequently, the receiving device <NUM> may compare the difference to a first distance threshold and/or may determine whether the difference falls within a first distance range. The receiving device <NUM> may then make the identification <NUM> of the potential collision when the receiving device <NUM> determines that the difference satisfies the first distance threshold and/or fall within the first distance range.

Additionally or alternatively, the receiving device <NUM> may base such identification on a distance between the first transmitting device <NUM> and the second transmitting device <NUM>. For example, the receiving device <NUM> may measure a distance between the first transmitting device <NUM> and the second transmitting device (e.g., based on receiving one of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM> and further based on receiving the resource reservation <NUM> from the second transmitting device <NUM>). Subsequently, the receiving device <NUM> may compare the distance to a second distance threshold and/or may determine whether the difference falls within a second distance range. The receiving device <NUM> may then make the identification <NUM> of the potential collision when the receiving device <NUM> determines that the distance satisfies the second distance threshold and/or fall within the second distance range.

Based upon the identification <NUM> of the potential collision, the receiving device <NUM> may make a determination <NUM> of where to send the feedback about the collision, which may be based on one or more rules, e.g., as further described herein. In other words, the receiving device <NUM> may determine which of the transmitting devices <NUM>, <NUM> should be informed about the identified collision. The receiving device <NUM> may generate the collision indication as a non-CTS <NUM>, which may indicate that the channel is not clear to send a transmission.

In some aspects, the receiving device <NUM> may transmit an indication (e.g., included in the non-CTS <NUM>) to the one of the transmitting devices <NUM>, <NUM> that indicates the resource reservation at a later time. For example, if the second transmitting device <NUM> sends the resource reservation <NUM> and the first transmitting device <NUM> sends the second resource reservation <NUM> (at least partially overlapping with the resource reservation <NUM>) after the second transmitting device <NUM> sends the resource reservation <NUM>, the receiving device <NUM> may send the non-CTS <NUM> to the first transmitting device <NUM>. The determination of the later reservation may be based on signal arrival time at the receiving device <NUM>. Therefore, whichever resource reservation signal arrives later at the receiving device <NUM> may be identified as the transmitting device that is not clear to send the transmission or that should be informed about the collision.

If the resource reservation signals arrive at the receiving device <NUM> at the same time, e.g., if the transmitting device <NUM> sends resource reservation <NUM>, then the receiving device <NUM> may send the indication to the first transmitting device <NUM> having the resource reservation <NUM> associated with a lower priority than the priority of the resource reservation <NUM> from the second transmitting device <NUM>. A respective priority may be based on the priority of the communication to be transmitted. The priority level may be based on a respective QoS and/or <NUM> QoS identifier (5QI) for the respective communication, which potentially may be indicated by each of the resource reservations <NUM>, <NUM>, <NUM>.

If the resource reservations <NUM>, <NUM> arrive at the receiving device <NUM> at the same time and the transmitting devices <NUM>, <NUM> have the same priority, the receiving device <NUM> may make the determination <NUM> based on the resources reserved by the transmitting devices <NUM>, <NUM> according to the resource reservations <NUM>, <NUM>. For example, the receiving device <NUM> may use a starting RB and/or an ending RB of the two sets of reserved resources to determine which of the two transmitting devices <NUM>, <NUM> should receive the non-CTS <NUM>. For example, the receiving device <NUM> may determine that the non-CTS <NUM> should be transmitted to the one of the transmitting devices <NUM>, <NUM> reserving a latest starting RB. However, if the two sets of reserved resources have the same starting RB, the receiving device <NUM> may determine that the non-CTS should be sent to the one of the transmitting devices <NUM>, <NUM> that reserves a latest ending RB of the two sets of reserved resources.

If the resource reservation signals arrive at the receiving device <NUM> at the same time, the transmitting devices have the same priority, and the reserved resources correspond to the same resource blocks, the receiving device may use a respective device identifier (ID) (e.g., UE ID) of the transmitting devices <NUM>, <NUM> to determine the one of the transmitting devices <NUM>, <NUM> that should receive the non-CTS <NUM>. The resource reservations <NUM>, <NUM> may be considered to arrive at the receiving device <NUM> at same time if the resource reservations <NUM>, <NUM> arrive within a threshold time of each other or if the receiving device <NUM> is unable to determine which of the resource reservations <NUM>, <NUM> was sent first.

If the resource reservation signals arrive at the receiving device <NUM> at the same time, the transmitting devices <NUM>, <NUM> have the same priority, and the reserved resources correspond to the same resource blocks, and the device IDs correspond, the receiving device <NUM> may randomly select the transmitting device that should back off from transmitting.

Upon making the determination <NUM> of which of the transmitting devices <NUM>, <NUM> is to receive the non-CTS <NUM>, the receiving device <NUM> may send an indication to the determined transmitting device. For example, in <FIG>, the receiving device <NUM> makes a determination <NUM> to send the collision feedback to the first transmitting device <NUM>; therefore, the receiving device <NUM> may transmit the non-CTS <NUM> to the first transmitting device <NUM>. The non-CTS <NUM> may indicate the collision, may inform the transmitting device <NUM> that the transmitting device is not clear to send, may indicate the first transmitting device <NUM> should back off from transmitting, etc. In response, the transmitting device <NUM> may refrain <NUM> from transmitting using the reserved resources indicated in the first or the second resource reservation <NUM>, <NUM> (e.g., the non-CTS <NUM> may indicate on which resources to refrain from transmitting).

The non-CTS <NUM> may be sent by the receiving device <NUM> using a common resource. The common resource may enable the transmitting devices <NUM>, <NUM> to be aware of the resources to monitor for such non-CTSs and/or other collision indications. The non-CTS <NUM> may be transmitted in a single frequency network manner, which may increase the chance of reception. The common resource may be a resource that is reserved by the transmitting devices <NUM>, <NUM> for such non-CTSs and/or other collision indications. For example, at least one of the transmitting devices <NUM>, <NUM> may transmit information that indicates, to the receiving device <NUM>, the resources to use to send feedback about whether a transmitting device may continue to transmit using the reserved resources and/or whether a transmitting device should back off. In some aspects, the common resource may be indicated in one of the resource reservations <NUM>, <NUM>, <NUM>. Alternatively, the receiving device <NUM> may send the indication as feedback on a feedback channel, such as a physical sidelink feedback channel (PSFCH). For example, for a groupcast, an acknowledgement sequence may be used to indicate a collision between reserved resources and/or a non-CTS.

Based upon receiving the non-CTS <NUM>, the first transmitting device <NUM> may refrain <NUM>, or back off, from using the reserved resources to transmit communication. Therefore, the first transmitting device <NUM> may refrain from transmitting during the resources indicated in at least one of the resource reservations <NUM>, <NUM>. The second transmitting device <NUM>, which does not receive any feedback from the receiving device <NUM> indicating that a non-CTS or collision, may proceed with a transmission <NUM> using the resources reserved by the resource reservation <NUM>.

<FIG> is a flowchart of a method <NUM> of wireless communication. The method <NUM> may be performed by a UE, receiving device, and/or other apparatus (e.g., UE <NUM>, <NUM>, <NUM>; receiving device <NUM>, <NUM>; RSC <NUM>, <NUM>; apparatus <NUM>). According to various aspects, one or more of the illustrated operations may be omitted, transposed, and/or contemporaneously performed.

At <NUM>, the receiving device receives a first resource reservation from a first transmitting device. In some aspects, the first resource reservation may include information indicating a priority, such as a QoS and/or 5QI. In some other aspects, the first resource reservation may indicate at least one resource associated with collision indication, such as at least one feedback resource and/or at least one common resource. The at least one resource may be on a feedback channel (e.g., PSFCH) and/or may be on a common channel, groupcast channel, and/or broadcast channel.

For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may receive a first resource reservation from the transmitting UE <NUM>. Referring to <FIG>, the device C <NUM> may receive a resource reservation from device A <NUM>. Referring to <FIG>, the receiving device <NUM> may receive the first and/or second resource reservation(s) <NUM>, <NUM> from the first transmitting device <NUM>.

At <NUM>, the receiving device receives a second resource reservation from a second transmitting device. In some aspects, the second resource reservation may include information indicating a priority, such as a QoS and/or 5QI. In some other aspects, the second resource reservation may indicate at least one resource associated with collision indication, such as at least one feedback resource and/or at least one common resource. The at least one resource may be on a feedback channel (e.g., PSFCH) and/or may be on a common channel, groupcast channel, and/or broadcast channel.

For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may receive a second resource reservation from one of the transmitting UEs <NUM>, <NUM>. Referring to <FIG>, the device C <NUM> may receive a resource reservation from device B <NUM>. Referring to <FIG>, the receiving device <NUM> may receive the resource reservation <NUM> from the second transmitting device <NUM>.

At <NUM>, the receiving UE identifies a collision between first resources reserved by the first transmitting device and second resources reserved by the second transmitting device. In some aspects, the receiving device may compare a first set of resources reserved by the first resource reservation and a second set of resources reserved by the second resource reservation by, first, comparing the first and second sets of resources and, next, determining that the first and second sets of resources include at least a subset of overlapping resources (e.g., on the same time/frequency resources).

In some other aspects, the receiving device may identify a collision between first resources reserved by the first transmitting device and second resources reserved by the second transmitting device based on respective measurements from the signals received from the two transmitting devices. For example, the receiving device may measure at least one first value (e.g., RSRP, SNR, SINR, RSRQ, etc.) based on signal(s) received from the first transmitting device, and may measure at least one second value (e.g., RSRP, SNR, SINR, RSRQ, etc.) based on signal(s) received from the second transmitting device. The receiving device may compare the at least one first value and at least one second value to determine if a difference between the values for the signals from the two transmitting devices is within a threshold level and/or within a range, such a preconfigured threshold level and/or preconfigured range.

In some further aspects, the receiving device may identify a collision between first resources reserved by the first transmitting device and second resources reserved by the second transmitting device based on a distance between the receiving device and each of the transmitting devices (e.g., the distance between the receiving device and the first transmitting device, as well as the distance between the receiving device and the second transmitting device). In still further aspects, the receiving device may identify a collision between first resources reserved by the first transmitting device and second resources reserved by the second transmitting device based on a distance between the two transmitting devices (e.g., the distance between the first and second transmitting devices). The receiving device may determine distances based on geolocation information associated with each of the receiving device, the first transmitting device, and the second transmitting device.

For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may identify a collision between first resources reserved by the transmitting UE <NUM> and second resources reserved by the transmitting UE <NUM> or the transmitting UE <NUM>. Referring to <FIG>, the device C <NUM> may identify a collision between first resources reserved by the transmitting device A <NUM> and second resources reserved by the transmitting device B <NUM>. Referring to <FIG>, the receiving device <NUM> may make the identification <NUM> of the potential collision between resources reserved by one of the resource reservations <NUM>, <NUM> from the first transmitting device <NUM> and resources reserved by the resource reservation <NUM> from the second transmitting device <NUM>.

At <NUM>, the receiving device may determine to transmit a collision indication to the first transmitting device or the second transmitting device based on the identified collision. In some aspects, the receiving device may determine a first time (e.g., time of arrival or timestamp) of reception of the first resource reservation from the first transmitting device and may determine a second time (e.g., time of arrival or timestamp) of reception of the second resource reservation from the second transmitting device. The receiving device may determine which of the first time or the second time is earlier, and the receiving device may determine to transmit the collision indication to the second transmitting device based on the second resource reservation being associated with the second time, which is later than the first time with which the first resource reservation is associated.

In some other aspects, the receiving device may receive the first resource reservation from the first transmitting device at a same time (e.g., based on a signal arrival time at the receiving device or based on timestamp) as receiving the second resource reservation from the second transmitting device. The receiving device may determine a respective priority associated with each of the first and second resource reservations (or each of the first and second transmitting devices), and the receiving device may determine to send the collision indication to the first transmitting device or the second transmitting device based, at least in part, on which respective priority is relatively higher between the first resource reservation from the first transmitting device and the second resource reservation from the second transmitting device.

In some further aspects, the receiving device may receive a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device, and the first and second transmitting devices (or first and second resource reservations) are associated with the same priority. The receiving device may determine to send the collision indication to the first transmitting device or the second transmitting device based, at least in part, on respective starting RBs and/or respective ending RBs reserved by each of the first and second resource reservations. For example, the receiving device may determine which of the first and second resource reservations reserves an earliest starting RB (or earliest ending RB), and the receiving device may determine to transmit the collision indication to the one of the first or second transmitting devices that reserved an earliest starting RB (or earliest ending RB).

In some additional aspects, the receiving device may receive the first resource reservation from the first transmitting device at a same time as receiving the second resource reservation from the second transmitting device, and the first and second transmitting devices (or first and second resource reservations) have a same priority and a same resource allocation. The receiving device may then determine to send the collision indication to the first transmitting device or the second transmitting device based, at least in part, on first device ID (e.g., UE ID) for the first transmitting device and a second device ID (e.g., UE ID) for the second transmitting device. For example, the receiving device may determine which of the first or second transmitting devices has a relatively lower UE ID.

In still further aspects, the receiving device may receive the first resource reservation from the first transmitting device at a same time as receiving the second resource reservation from the second transmitting device, and the first and second transmitting devices (or first and second resource reservations) have a same priority and a same resource allocation and, further, have a respective device IDs from which the receiving device cannot determine which is lower (e.g., the same device IDs). Accordingly, the receiving device may randomly select the first or second transmitting device to which to transmit the collision indication.

For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may determine to transmit a collision indication to one of the transmitting UEs <NUM>, <NUM>, <NUM>. Referring to <FIG>, the device C <NUM> may determine to transmit a collision indication to one of device A <NUM> or device B <NUM>. Referring to <FIG>, the receiving device <NUM> may make the determination <NUM> between the first or the second transmitting device <NUM>, <NUM> to which to transmit the non-CTS <NUM>.

At <NUM>, the receiving device transmits the collision indication to the determined one of the first transmitting device or the second transmitting device. In some aspects, the collision indication may include a non-CTS signal. In some other aspects, the receiving device may transmit the collision indication on a feedback channel (e.g., PSFCH). In still further aspects, the receiving device may transmit the collision indication on at least one resource (e.g., at least one common resource) that is indicated by the determined one of the first transmitting device or the second transmitting device (e.g., in the respective one of the first resource reservation or second resource reservation).

For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may transmit the collision indication to the determined one of the transmitting UEs <NUM>, <NUM>, <NUM>. Referring to <FIG>, the device C <NUM> may transmit the collision indication to the determined one of device A <NUM> or device B <NUM>. Referring to <FIG>, the receiving device <NUM> may transmit the non-CTS <NUM> to the first transmitting device <NUM> based on the determination <NUM> of where to transmit the feedback.

At <NUM>, the receiving device may receive a transmission on resources reserved by the one of the first or second resource reservations corresponding to the other one (non-determined one) of the first transmitting device or the second transmitting device. For example, referring to <FIG>, the receiving UE <NUM> and/or RSC <NUM> may receive one of the transmissions <NUM>, <NUM>, <NUM> from the other (non-determined) one of the transmitting UEs <NUM>, <NUM>, <NUM>. Referring to <FIG>, the device C <NUM> may receive one of the transmissions <NUM>, <NUM> from to the other (non-determined) one of device A <NUM> or device B <NUM>. Referring to <FIG>, the receiving device <NUM> may receive the transmission <NUM> on the reserved resources from the second transmitting device <NUM>.

<FIG> is a flowchart of a method <NUM> of wireless communication. The method <NUM> may be performed by a UE, transmitting device, and/or other apparatus (e.g., UE <NUM>', <NUM>", <NUM>, <NUM>, <NUM>, <NUM>; transmitting device <NUM>, <NUM>, <NUM>, <NUM>; RSC <NUM>, <NUM>; apparatus <NUM>). According to various aspects, one or more of the illustrated operations may be omitted, transposed, and/or contemporaneously performed.

At <NUM>, the transmitting device may transmit a resource reservation for a transmission from the transmitting device to at least one receiving device. In some aspects, the resource reservation may include information indicating a priority, such as a QoS and/or 5QI. In some other aspects, the resource reservation may indicate at least one resource associated with collision indication, such as at least one feedback resource and/or at least one common resource. The at least one resource may be on a feedback channel (e.g., PSFCH) and/or may be on a common channel, groupcast channel, and/or broadcast channel.

For example, referring to <FIG>, the transmitting UE <NUM> may transmit a resource reservation to the receiving UE <NUM> and/or RSC <NUM>. Referring to <FIG>, the device A <NUM> may transmit a resource reservation to device C <NUM>. Referring to <FIG>, the first transmitting device <NUM> may transmit the first and/or second resource reservation(s) <NUM>, <NUM> to the receiving device <NUM>.

At <NUM>, the transmitting device may receive a collision indication from a receiving device of the at least one receiving device for a collision between resources reserved by the resource reservation and resources reserved by another transmitting device. The transmitting device may receive the collision indication in a collision indication resource reserved by the transmitting device for the collision indication. The transmitting device may indicate the collision indication resource in the resource reservation. The transmitting device may receive the collision indication on a feedback channel (e.g., PSFCH), a common channel, a groupcast channel, and/or broadcast channel. The collision indication may include a feedback sequence for a non-CTS indication.

For example, referring to <FIG>, the transmitting UE <NUM> may receive a collision indication from the receiving UE <NUM> and/or RSC <NUM>. Referring to <FIG>, the device A <NUM> may receive a collision indication from the device C <NUM>. Referring to <FIG>, the first transmitting device <NUM> may receive the non-CTS <NUM> from the receiving device <NUM>.

At <NUM>, the transmitting device backs off from transmitting during the resources reserved by the resource reservation in response to receiving the collision indication from the receiving device. For example, the transmitting device may refrain from transmitting on the resources reserved by the resource reservation in response to receiving the collision indication from the receiving device, or the transmitting device may reduce a transmission power. Illustratively, the transmitting device may determine a time period (e.g., based on a timer that is started in response to receiving the collision indication) to refrain from transmitting during the resources reserved by the resource reservation in response to receiving the collision indication from the receiving device, and the transmitting device may refrain from transmitting during the resources reserved by the resource reservation for the duration of the time period. After the time period, the transmitting device may determine whether the resources earlier reserved by the resource reservation are now clear (e.g., no interfering transmissions are detected), and the transmitting device may transmit. In another illustration, the transmitting device may determine an amount by which to reduce a transmission power, and the transmitting device may then transmit during the resources reserved by the resource reservation with the reduced transmission power.

For example, referring to <FIG>, the transmitting UE <NUM> may back off from transmission <NUM> on resources reserved by the resource reservation. Referring to <FIG>, the device A <NUM> may back off the transmission <NUM>. Referring to <FIG>, the first transmitting device <NUM> may refrain from transmitting on resources reserved by the first or second resource reservations <NUM>, <NUM> in response to receiving the non-CTS <NUM> from the receiving device <NUM>.

In some aspects, the transmitting device may back off from transmitting during the resources reserved by the resource reservation by refraining from transmitting the transmission on the resources reserved by the resource reservation for at least a duration of a backoff timer, as shown at <NUM>. For example, the transmitting device may begin a backoff timer (e.g., countdown timer) in response to receiving the collision indication.

For example, referring to <FIG>, the transmitting UE <NUM> may refrain from transmitting the transmission <NUM> on the resources reserved by the resource reservation for at least a duration of a backoff timer. Referring to <FIG>, the device A <NUM> may refrain from transmitting the transmission <NUM> on the resources reserved by the resource reservation for at least a duration of a backoff timer. Referring to <FIG>, the first transmitting device <NUM> may refrain from transmitting on resources reserved by the first or second resource reservations <NUM>, <NUM> in response to receiving the non-CTS <NUM> from the receiving device <NUM>.

When the backoff timer expires (or counts up to a predetermined time), then, at <NUM>, the transmitting device may transmit another resource reservation for the transmission from the transmitting device. For example, referring to <FIG>, the transmitting UE <NUM> may transmit another resource reservation for the transmission <NUM> after the duration of the backoff timer. Referring to <FIG>, the device A <NUM> may refrain from transmitting the transmission <NUM> on the resources reserved by the resource reservation for at least a duration of a backoff timer. Referring to <FIG>, the first transmitting device <NUM> may refrain from transmitting on resources reserved by the first or second resource reservations <NUM>, <NUM> in response to receiving the non-CTS <NUM> from the receiving device <NUM>.

The apparatus <NUM> may be a UE (e.g., the UE <NUM>) and includes a cellular baseband processor <NUM> (also referred to as a modem) coupled to a cellular RF transceiver <NUM> and one or more subscriber identity modules (SIM) cards <NUM>, an application processor <NUM> coupled to a secure digital (SD) card <NUM> and a screen <NUM>, a Bluetooth module <NUM>, a wireless local area network (WLAN) module <NUM>, a Global Positioning System (GPS) module <NUM>, and a power supply <NUM>. The cellular baseband processor <NUM> communicates through the cellular RF transceiver <NUM> with the UE <NUM>', RSC <NUM>, and/or BS <NUM>/<NUM>.

The reception component <NUM> may be configured to receive a first resource reservation from a transmitting UE <NUM>', e.g., as described in connection with <NUM> of <FIG>. The reception component <NUM> may be further configured to receive a second resource reservation from a transmitting RSC <NUM>, e.g., as described in connection with <NUM> of <FIG>. The reception component <NUM> may provide input(s) to a collision identification component <NUM> based on the first resource reservation and the second resource reservation.

The communication manager <NUM> includes a collision identification component <NUM> that is configured to identify a collision between first resources reserved by the transmitting UE <NUM>' and second resources reserved by the RSC <NUM>, e.g., as described in connection with <NUM> of <FIG>. The communication manager <NUM> further includes a device selection component <NUM> that receives input(s) based on the identified collision from the collision identification component <NUM> and is configured to determine to transmit a collision indication to the transmitting UE <NUM>' or the RSC <NUM> based on the identified collision, e.g., as described in connection with <NUM> of <FIG>.

The communication manager <NUM> further includes a collision indication component <NUM> that receives input(s) based on the determined one of the transmitting UE <NUM>' or the RSC <NUM> from the device selection component <NUM>. The collision indication component <NUM> is configured to generate a collision indication for transmission to the determined one of the transmitting UE <NUM>' or the RSC <NUM>, e.g., as described in connection with <NUM> of <FIG>.

Further, the reception component <NUM> may be configured to receive a transmission on the resources reserved by the other (non-determined) one of the transmitting UE <NUM>' or the RSC <NUM>.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned call flow diagram of <FIG> and/or flowchart of <FIG>. As such, each block in the aforementioned call flow diagram of <FIG> and/or flowchart of <FIG> may be performed by a component and the apparatus may include one or more of those components.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for identifying a collision between first resources reserved by a first transmitting device and second resources reserved by a second transmitting device; and means for transmitting a collision indication to the first transmitting device or the second transmitting device based on the identified collision.

In one aspect, the identification of the collision is based on an overlap between the first resources and the second resources. In one aspect, the identification of the collision is further based on a difference in a measured RSRP for a first signal indicating the first resources reserved by the first transmitting device and a second signal indicating the second resources reserved by the second transmitting device.

In one aspect, the identification of the collision is further based on a distance between the receiving device and the first transmitting device and the second transmitting device or between the first transmitting device and the second transmitting device.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device; and means for receiving a second resource reservation from the second transmitting device after receiving the first resource reservation, and the transmission of the collision indication is to the second transmitting device based on the second resource reservation being received after the first resource reservation.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device; and means for determining to transmit the collision indication to the first transmitting device or the second transmitting device based, at least in part, on a first priority of communication associated with the first transmitting device and a second priority of communication associated with the second transmitting device.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device, and the first transmitting device and the second transmitting device have a same priority; and means for determining to transmit the collision indication to the first transmitting device or the second transmitting device based, at least in part, on a starting RB for the first resources and a starting RB for the second resources.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device, and the first transmitting device and the second transmitting device have a same priority; and means for determining to transmit the collision indication to the first transmitting device or the second transmitting device based, at least in part, on an ending RB for the first resources and an ending RB for the second resources.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device, and the first transmitting device and the second transmitting device have a same priority and a same resource allocation; and means for determining to transmit the collision indication to the first transmitting device or the second transmitting device based, at least in part, on first device ID for the first transmitting device and a second device ID for the second transmitting device.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device at a same time as receiving a second resource reservation from the second transmitting device, and the first transmitting device and the second transmitting device have a same priority, has a same resource allocation, and are associated with a same set of bits for a device ID; and means for randomly determining to transmit the collision indication to the first transmitting device or the second transmitting device.

In one aspect, the collision indication is transmitted on a resource reserved for the collision indication by the first transmitting device or the second transmitting device.

In one aspect, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, may include means for receiving a first resource reservation from the first transmitting device having an associated first collision indication resource; and means for receiving a second resource reservation from the second transmitting device after receiving the first resource reservation having a second collision indication resource, and the collision indication is transmitted using the associated first collision indication resource or the associated second collision indication resource.

In one aspect, the collision indication is transmitted on a feedback channel. In one aspect, the collision indication comprises a feedback sequence for a non-CTS indication.

The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described supra, the apparatus <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

The cellular baseband processor <NUM> communicates through the cellular RF transceiver <NUM> with the UE <NUM>, RSC <NUM>, and/or BS <NUM>/<NUM>.

The communication manager <NUM> includes a resource reservation component <NUM> that is configured to generate a resource reservation for a transmission to the receiving UE <NUM> and/or RSC <NUM>. The transmission component <NUM> may transmit the resource reservation for a transmission to the receiving UE <NUM> and/or RSC <NUM>, e.g., as described in connection with <NUM> of <FIG>. The communication manager <NUM> further includes a CTS component <NUM> that receives input(s) from the reception component <NUM> and is configured to receive a collision indication from at least one of the receiving UE <NUM> and/or RSC <NUM> for a collision between resources reserved by the resource reservation and resources reserved by another transmitting device, e.g., as described in connection with <NUM> of <FIG>. The communication manager <NUM> further includes a back off component <NUM> that receives input(s) based on the collision indication from the CTS component <NUM> and is configured to back off from transmitting on the resources reserved by the resource reservation in response to receiving the collision indication from at least one of the receiving UE <NUM> and/or RSC <NUM>, e.g., as described in connection with <NUM> of <FIG>.

The back off component <NUM> may be further configured to refrain from transmitting the transmission on the resources reserved by the resource reservation for at least a duration of a backoff timer, e.g., as described in connection with <NUM> of <FIG>. The back off component <NUM> may provide input(s) to the resource reservation component <NUM>, and the resource reservation component <NUM> may be configured to generate another resource reservation for the transmission to at least one of the receiving UE <NUM> and/or RSC <NUM> after the duration of the backoff timer. The transmission component <NUM> may transmit the resource reservation for the transmission to at least one of the receiving UE <NUM> and/or RSC <NUM> after the duration of the backoff timer, e.g., as described in connection with <NUM> of <FIG>.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for transmitting a resource reservation for a transmission from the transmitting device to at least one receiving device; means for receiving a collision indication from a receiving device of the at least one receiving device for a collision between resources reserved by the resource reservation and resources reserved by another transmitting device; and means for backing off from transmitting on the resources reserved by the resource reservation in response to receiving the collision indication from the receiving device.

In one aspect, the collision indication is received on a collision indication resource reserved for the collision indication. In one aspect, the resource reservation includes the collision indication resource. In one aspect, the collision indication is received on a feedback channel. In one aspect, the collision indication includes a feedback sequence for a non-CTS indication.

In one aspect, the means for backing off from transmitting on the resources reserved by the resource reservation is configured to refrain from transmitting the transmission on the resources reserved by the resource reservation for at least a duration of a backoff timer; and transmit another resource reservation for the transmission to the at least one receiving device after the duration of the backoff timer.

Claim 1:
A method of wireless communication at a receiving device, comprising:
receiving (<NUM>) a first resource reservation from a first transmitting device;
receiving (<NUM>) a second resource reservation from a second transmitting device;
identifying (<NUM>) a collision between the first resources reserved by the first transmitting device and the second resources reserved by the second transmitting device based on the received first resource reservation and the received second resource reservation; and
transmitting (<NUM>) a collision indication to the first transmitting device or the second transmitting device based on the identified collision.