Patent Description:
Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for feedback signaling.

3GPP document R1-<NUM> of LG Electronics describes aspects of physical layer procedures for NR sidelink.

After considering this discussion, and particularly after reading the section entitled "Detailed Description" one will understand how the features of this disclosure provide advantages that include improved feedback signaling.

Certain aspects provide a method for wireless communication by a user-equipment, UE, according to independent claim <NUM>, an apparatus for wireless communication by a UE according to independent claim <NUM> and a computer-readable medium according to independent claim <NUM>.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for distance-based hybrid automatic repeat request (HARQ) feedback transmission. For sidelink communication, an acknowledgement feedback from a data receiver user-equipment (UE) (also referred to as a "Rx UE") to a data transmitter UE (also referred to as a "Tx UE") may only be sent if the distance between the UEs is less than a threshold. Thus, the Rx UE may determine the distance between the Rx UE and the Tx UE for HARQ transmission. In certain aspects of the present disclosure, the distance between the UEs may be determined using geographical zones to reduce signaling overhead. In other words, instead of the Tx UE transmitting the exact coordinates of the Tx UE to the Rx UE for the Rx UE to determine the distance, the Tx UE may transmit an identifier of geographical zone in which the Tx UE is located. The Rx UE may then determine the distance based on the zone ID indicated by the Tx UE, as well as the coordinates of the Rx UE or another zone ID of a zone in which the Rx UE is located.

The following description provides examples of distance-based HARQ feedback in communication systems, and is not limiting of the scope, applicability, or examples set forth in the claims.

According to certain aspects, the BSs <NUM> and UEs <NUM> may be configured for distance-based on HARQ signaling. As shown in <FIG>, the UE 120a includes a HARQ manager <NUM>. The HARQ manager <NUM> may be configured to determine a distance between the UE 120a and UE 120t, based on which the UE may determine whether to transmit HARQ feedback, in accordance with aspects of the present disclosure.

Wireless communication network <NUM> may also include relay stations (e.g., relay station <NUM>10r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE <NUM> or a BS <NUM>), or that relays transmissions between UEs <NUM>, to facilitate communication between devices.

At the BS 110a, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. The transmit processor <NUM> may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a-232t. Downlink signals from modulators 232a-232t may be transmitted via the antennas 234a-234t, respectively.

At the UE 120a, the antennas 252a-252r may receive the downlink signals from the BS 110a and may provide received signals to the demodulators (DEMODs) in transceivers 254a-254r, respectively. A MIMO detector <NUM> may obtain received symbols from all the demodulators 254a-254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor <NUM> may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink <NUM>, and provide decoded control information to a controller/processor <NUM>.

On the uplink, at UE 120a, a transmit processor <NUM> may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source <NUM> and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by the demodulators in transceivers 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the uplink signals from the UE 120a may be received by the antennas <NUM>, processed by the modulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE 120a.

The controller/processor <NUM> and/or other processors and modules at the UE 120a may perform or direct the execution of processes for the techniques described herein. As shown in <FIG>, the controller/processor <NUM> of the UE 120a has a HARQ manager <NUM> that may be configured to determine a distance between the UE 120a and UE 120t, based on which the UE may determine whether to transmit HARQ feedback, according to aspects described herein. Although shown at the Controller/Processor, other components of the UE 120a and BS 110a may be used performing the operations described herein.

<FIG> show diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure. For example, the UEs shown in <FIG> may communicate via sidelink channels and may perform sidelink CSI reporting as described herein.

The V2X systems, provided in <FIG> provide two complementary transmission modes. A first transmission mode, shown by way of example in <FIG>, involves direct communications (for example, also referred to as side link communications) between participants in proximity to one another in a local area. A second transmission mode, shown by way of example in <FIG>, involves network communications through a network, which may be implemented over a Uu interface (for example, a wireless communication interface between a radio access network (RAN) and a UE).

Referring to <FIG>, a V2X system <NUM> (for example, including vehicle to vehicle (V2V) communications) is illustrated with two UEs <NUM>, <NUM> (e.g., vehicles). The first transmission mode allows for direct communication between different participants in a given geographic location. As illustrated, a vehicle can have a wireless communication link <NUM> with an individual (V2P) (for example, via a UE) through a PC5 interface. Communications between the UEs <NUM> and <NUM> may also occur through a PC5 interface <NUM>. In a like manner, communication may occur from a UE <NUM> to other highway components (for example, highway component <NUM>), such as a traffic signal or sign (V2I) through a PC5 interface <NUM>. With respect to each communication link illustrated in <FIG>, two-way communication may take place between elements, therefore each element may be a transmitter and a receiver of information. The V2X system <NUM> may be a self-managed system implemented without assistance from a network entity. A self-managed system may enable improved spectral efficiency, reduced cost, and increased reliability as network service interruptions do not occur during handover operations for moving vehicles. The V2X system may be configured to operate in a licensed or unlicensed spectrum, thus any vehicle with an equipped system may access a common frequency and share information. Such harmonized/common spectrum operations allow for safe and reliable operation.

As illustrated in <FIG>, the UE <NUM> may be in a zone <NUM> associated with a zone ID (e.g., zone ID = <NUM>). However, the zone ID may correspond to multiple zones, such as zone <NUM> and zone <NUM>, as illustrated. In some aspects of the present disclosure, the UE <NUM> may receive an indication of the zone ID (e.g., <NUM>), and determine multiple distances for each of the zones indicated by the zone ID. For example, the UE may determine a distance between the UE <NUM> and the zone <NUM> in which the UE <NUM> is located, and a distance between the UE <NUM> and zone <NUM>. The UE <NUM> may then determine the distance between the UE <NUM> and the UE <NUM> to be a minimum of the determined distances to zones <NUM>, <NUM>.

<FIG> shows a V2X system <NUM> for communication between a UE <NUM> (e.g., vehicle) and a UE <NUM> (e.g., vehicle) through a network entity <NUM>. These network communications may occur through discrete nodes, such as a base station (for example, an eNB or gNB), that sends and receives information to and from (for example, relays information between) UEs <NUM>, <NUM>. The network communications through vehicle to network (V2N) links <NUM> and <NUM> may be used, for example, for long range communications between vehicles, such as for communicating the presence of a car accident a distance ahead along a road or highway. Other types of communications may be sent by the node to vehicles, such as traffic flow conditions, road hazard warnings, environmental/weather reports, and service station availability, among other examples. Such data can be obtained from cloud-based sharing services.

In some circumstances, two or more subordinate entities (for example, UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via a sidelink. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. Generally, a sidelink may refer to a direct link between one subordinate entity (for example, UE1) and another subordinate entity (for example, UE2). As such, a sidelink may be used to transmit and receive a communication (also referred to herein as a "sidelink signal") without relaying the communication through a scheduling entity (for example, a BS), even though the scheduling entity may be utilized for scheduling or control purposes. In some examples, a sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable proximal devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configurations and other parameters used for data transmissions, and the PSSCH may carry the data transmissions. The PSFCH may carry feedback such as channel state information (CSI) related to a sidelink channel quality.

Certain aspects of the present disclosure are generally directed to sidelink communication (e.g., communication between UEs, such as vehicle-to-vehicle <V2V/V2X> communications, as described with respect to <FIG>). In V2X communications, hybrid automatic repeat request (HARQ) feedback transmission may be based on distance. For example, a data receiver UE (also referred to herein as "Rx UE") may send HARQ feedback back to a data transmitter UE (also referred to herein as "Tx UE") only when the distance between the UEs is smaller than a distance threshold. For distance based HARQ, geographical location of the Tx UE may be determined at the Rx UE in order for the Rx UE to determine whether to transmit HARQ feedback. For instance, the Tx UE may indicate its location to the Rx UE so that the UE is able to determine the distance from the Tx UE's location and the location of the Rx UE.

Certain aspects of the present disclosure are directed to determining a distance between an Rx UE and a Tx UE using geographical zones. Geographical zones are used for the signaling of UE location with reduced overhead. For instance, the earth may be partitioned into zones based on Global Navigation Satellite System (GNSS) positioning, each zone having a configured size (e.g., <NUM> x <NUM> meters). Part of a zone identifier (ID) (e.g., least significant bits (LSBs) of a zone ID) may be signaled from a Tx UE to a Rx UE for the purpose of determining the distance between the UEs for distance based HARQ feedback. The signaling overhead may be reduced as compared to directly signaling the UE's location (e.g., latitude and longitude coordinates), which is important since the signaling overhead associated with indicating the absolute location/coordinates of the Tx UE may not be acceptable at lower layers.

<FIG> and <FIG> illustrate a cluster of zones <NUM> including a zone <NUM> in which an Rx UE may be located. The zone <NUM> may be associated with a zone ID. In certain aspects, a zone ID of a zone in which an Rx UE is located (or tx UE is located) may be computed by an Rx UE (or a Tx UE), using the following equation:.

where L is the length of a zone, W is the width of a zone, Nx is the number of zones in a longitudinal direction, Ny is the number of zones in a latitudinal direction, and x (or y) is the geodesic distance in longitude (or in latitude) between UE's current location and geographical coordinates (<NUM>, <NUM>) (e.g., the equator and prime meridian). In other words, x (e.g., latitudinal distance) and y (e.g., longitudinal distance) represent the location of the UE. The higher Nx and Ny are, the higher the resource overhead for indicating the zone ID. For example, <NUM> bits may be used to indicate zone ID if Nx = Ny = <NUM><NUM> = <NUM> (e.g., <NUM> bits for Nx and <NUM> bits for Ny). For the cluster of zones <NUM> illustrated in <FIG>, Nx = Ny = <NUM>. The UE may determine that x<NUM> is equal to <NUM> and y<NUM> is equal to <NUM> for zone <NUM>. Therefore, the zone ID associated with zone <NUM> may be equal to <NUM> (e.g., <NUM> x <NUM> + <NUM> = <NUM>).

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication, in accordance with certain aspects of the present disclosure. The operations <NUM> may be performed, for example, by a UE (e.g., Rx UE) (e.g., such as a UE 120a in the wireless communication network <NUM>).

Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor <NUM> of <FIG>). Further, the transmission and reception of signals by the UE in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> begin, at block <NUM>, with the UE monitoring for a data transmission from another UE (e.g., Tx UE). At block <NUM>, the UE receives, from another UE (e.g., Tx UE), an indication of a first zone identifier (ID). In certain aspects, the UE at block <NUM>, determines a nearest zone to the UE of multiple zones, wherein the multiple zones are determined based at least in part on the indication of the first zone ID, and at block <NUM>, determines a distance between the UE and the other UE based on the first zone ID. The determined distance is a distance between the UE and the nearest zone. The distance may be determined based on a location of the Rx UE (e.g., geodesic distance coordinates), and the zone ID of the Tx UE, or based on the zone IDs of the Rx UE and the Tx UE, as described in more detail herein. At block <NUM>, the UE transmits HARQ feedback for the data transmission based on the distance.

In other words, an Rx UE receives the zone ID indication and data transmission from a Tx UE. The zone ID indication may be carried in sidelink control information, medium access control (MAC) control element, higher layer signaling, or any combination thereof. The higher layer signaling may include any signaling associated with a layer above the MAC layer, such as RRC signaling.

In certain aspects, the Rx UE determines distance from the Tx UE to the Rx UE, based on Tx UE's zone ID indication and the Rx UE's location. The Rx UE then determines to send HARQ feedback to the Tx UE based at least on the determined distance. In one example, the UE may transmit the HARQ feedback if the determined distance is less than a distance threshold and the feedback is a negative acknowledgment (NACK). That is, the HARQ feedback may be implemented as a NACK-only feedback. The UE may only send a NACK feedback, and not send feedback if the HARQ feedback is an acknowledgement (ACK) and the distance between the UE and the other UE is below the distance threshold. In another example, the UE may transmit the HARQ feedback if the determined distance is less than a distance threshold, regardless of whether the HARQ feedback is an ACK feedback or a NACK feedback.

In certain aspects, the determination of the distance, at block <NUM>, may be based on the zone IDs associates with the zones in which the Rx UE and the Tx UE are located. For example, the Rx UE may determine the zone ID of the zone in which the Rx UE is located based on the geographical location (ego zone) of the Rx UE. The Rx UE computes the distance between the Tx UE and the Rx UE, based on the zone ID of the Rx UE, the zone ID of the Tx UE, and the zone size. The distance may be the distance between reference points of both zones. A reference point of a zone may be the center of the zone, in some examples. Thus, the distance between reference points may be the distance between center of the Rx UE zone and the center of the Tx UE zone. In another example, reference point of a zone may be one of the four corners of the zone. In other words, the Rx UE may determine how far apart the Tx UE and the Rx UE are in terms of number (quantity) of zones based on zone IDs. The Rx UE may then convert the separation of number of zones to distance (e.g., in meters, when the HARQ feedback distance requirement is also expressed in meters) based on the zone size (e.g., length and width of a zone).

<FIG>, <FIG> illustrates a cluster of zones <NUM> including a zone <NUM> in which an Rx UE may be located and a zone <NUM> in which a Tx UE is located, in accordance with certain aspects of the present disclosure. As illustrated in <FIG>, in certain aspects, the distance <NUM> between the Rx UE <NUM> and the Tx UE <NUM> may be determined based on the distance between reference points <NUM>, <NUM> (e.g., centers) of the respective zones <NUM>, <NUM> of the Rx UE <NUM> and the Tx UE <NUM>. The Rx UE <NUM> may be configured with a length L of a zone, and a width W of the zone, as well as Nx and Ny which are the number of zones that may be indicated for the longitude and latitude directions, respectively. For example, in the example cluster of zones <NUM>, Nx = Ny = <NUM> zones, which may be indicated using <NUM> bits (e.g., <NUM><NUM>=<NUM>), and a total of <NUM> bits may be used to indicate a zone.

An Rx UE may first determines (x,y) (also referred to as "geodesic distance coordinates") from its geographical coordinates. As described herein, x and y refers to the geodesic distance in longitude and in latitude, respectively, between the UE's current location and a reference point on earth (e.g., the geographical coordinates (<NUM>, <NUM>)). Based on (x, y), Rx UE determines its zone ID (e.g., <NUM>). In the example of <FIG>, x<NUM>,Rx = <NUM>, y<NUM>,Rx = <NUM> for the Rx UE. The Rx UE also receives the Tx UE's zone ID indication (e.g., <NUM>), based on which the Rx UE determines x<NUM>,Tx = <NUM>, y<NUM>,Tx = <NUM> for the Tx UE, based on the following equations, which is the inversion of the zone ID computation, Zone ID = y<NUM> * Nx + x<NUM>: <MAT> <MAT>.

Based on the two zone IDs, the Rx UE determines the distance between the two corresponding zones, in terms of number of zones. For the example provided in <FIG>, the distance expressed by number of zones may be dx = |x<NUM>,Rx - x<NUM>,Tx| = <NUM> zones in longitude and dy = |y<NUM>,Rx - y<NUM>,Tx| = <NUM> zone in latitude. Thus, the distance between the two zones may be determined (e.g., estimated) based on the equation: <MAT>.

In other words, the Rx UE determines the transmitter-receiver distance <NUM> to be the distance between reference points <NUM>, <NUM> in both zones <NUM>, <NUM>. The reference point may be common to all zones. For example, the reference point may be the center of a zone, or one of the four corners of the zone such as the point closest to geographical location (<NUM>, <NUM>) (e.g., the equator and the prime meridian).

As illustrated in <FIG>, the determined distance <NUM> to be used for HARQ may be the distance between the actual location of the Rx UE <NUM> and the location of the zone <NUM> (e.g., location of the reference point <NUM> of the zone <NUM>) in which the Tx UE <NUM> is located. For example, the Rx UE computes the distance between the two sets of coordinates (e.g., the coordinates of the zone indicated by Tx UE, and the coordinates of the Rx UE). The coordinates may be geodesic distances based on World Geodetic System (WGS) (e.g., WGS84 model). In other words, the coordinates of the Rx UE may be geodesic distance coordinates x and y, where x (or y) is the geodesic distance in longitude (or in latitude) between UE's current location and a reference point on the earth, for example, geographical coordinates (<NUM>, <NUM>) (e.g., the equator and prime meridian), as described herein.

The determination of Tx UE's accurate coordinates at the Rx UE may be difficult if the Tx UE only signals a zone ID of the zone in which the Tx UE is located. Therefore, the Rx UE determines the coordinates of a reference point (e.g., center) of the Tx UE's zone, and computes distance based on the two the coordinates of the reference point of the Tx UE's zone and the coordinates of the Rx UE.

As described herein, the coordinates are coordinates expressed in distance (or length). For example, the two values in the geodesic distance coordinates are geodesic distance from coordinates (<NUM>, <NUM>) in longitude and latitude, respectively. For the Tx UE, the geodesic distance coordinates are for a reference point of the zone in which the Tx UE is located, but for the Rx UE, the coordinates of the Rx UE are (x, y), which are a more accurate representation of the Rx UEs location (e.g., as compared to using geodesic distance coordinates of a reference point in a zone). The determination of the Tx UE's geodesic distance coordinates (e.g., coordinates of Tx UE's zone) may be determined by the Rx UE by first determining the zone ID of the Rx UE based on (x, y). The Rx UE can then determine how far apart the Rx UE is from the Tx UE in terms of a number of zones.

The Rx UE determines geodesic distance coordinates of the Rx UE's zone (x<NUM>, y<NUM>), based on zone size (length/width) and zone ID. Here, the coordinates of the Rx UE's zone are the coordinates of a reference point in the zone, expressed in distance (or length). The Rx UE then determines coordinates of Tx UE's zone (x<NUM>,Tx, y<NUM>,Tx), based on the coordinates of the Rx UE's zone, and the distance between the two zones in terms of number of zones. The distance of the two UEs may be determined as distance between (x, y) and (x<NUM>,Tx, y<NUM>,Tx). In certain aspects, the distance may be computed (e.g., estimated) assuming the two sets of coordinates are on 2D surface.

As an example, the Rx UE may determine a zone size (e.g., L being the length of a zone and W being the width of a zone), and determine Nx/Ny which are the number of zones that can be indicated in longitude/latitude (e.g., assuming Nx=Ny = <NUM><NUM> = <NUM>), as described herein. The Rx UE's coordinates may be (x, y), x (or y) being the geodesic distance in longitude (or latitude) between UE's current location and geographical coordinates (<NUM>, <NUM>), as described herein. The Rx UE may determine (x, y) from its geographical coordinates. Based on (x, y), Rx UE determines the zone ID (e.g., <NUM>, i.e. x<NUM>,Rx = <NUM>, y<NUM>,Rx = <NUM>) of the zone in which the Rx UE is located. Based on (x, y), the Rx UE determines coordinates of its zone (x<NUM>, y<NUM>) (e.g., a reference point of the zone in which Rx UE is located). For example, (x<NUM>, y<NUM>) may be determined based on the following equation (e.g., they are coordinates of center of the zone expressed in distances): <MAT> <MAT>.

The Rx UE also receives the Tx UE's zone ID indication (e.g., <NUM> in the example of <FIG>). Tx UE's zone ID may be converted to a zone indication in longitude and latitude (e.g., x<NUM> and y<NUM>). In this example, for zone ID = <NUM>, it is determined that x<NUM>,Tx = <NUM>, y<NUM>,Tx = <NUM>, using equations described herein. Based on the zone IDs of the Tx UE and Rx UE, the Rx UE determines that the distance between the zones in which the Rx UE and the Tx UE are located, in terms of number of zones, which may be dx = x<NUM>,Tx - x<NUM>,Rx = <NUM> zones in longitude, dy = y<NUM>,Tx - y<NUM>,Rx = - <NUM> zones in latitude, in the example of Rx UE and Tx UE locations illustrated in <FIG>. The Rx UE then determines coordinates of the Tx UE's zone (x<NUM>,Tx, y<NUM>,Tx). For example, the coordinates of the Tx UE's zone may be determined using the following equations: <MAT> <MAT> The distance between the Rx UE and the Tx UE is then determined using the equation: <MAT>.

Certain aspects of the present disclosure provide techniques for an Rx UE to determine distance between UEs using zone ID signaling. For example, certain aspects provide techniques for a simplified distance estimation technique using the zone IDs of the Rx UE and Tx UE, and other aspects provide techniques for a more accurate (yet more complicated) distance estimation technique using both zone ID and geodesic distance coordinates.

<FIG> illustrates multiple zone clusters in which an Rx UE and Tx UE may be located, in accordance with certain aspects of present disclosure. As used herein, a cluster generally refers to a set or group of zones. A zone ID indication from a Tx UE to an Rx UE may be ambiguous since multiple zones may have the same zone IDs. In other words, because only a part (e.g., LSB) of a zone ID may be indicated to save signaling overhead, the indicated zone ID may repeat after some distance (e.g., making up a zone cluster). In a zone cluster, each zone has a unique zone ID. For example, three zone clusters <NUM>, <NUM>, <NUM> are illustrated in <FIG>. All the zones <NUM>, <NUM>, <NUM> may have the same zone IDs (e.g., x<NUM> is equal to <NUM> and y<NUM> is equal to <NUM> for all of the zones <NUM>, <NUM>, <NUM>). Therefore, when a Rx UE receives a zone ID indication from a Tx UE, the zone ID may indicate a zone in the same cluster (e.g., zone cluster <NUM>) in which the Rx UE is located, or a zone in a different zone cluster (e.g., zone cluster <NUM>, <NUM>). Thus, the Rx UE may determine which zone the Tx UE is assumed to be in for distance calculation, since the computed distance based on different zone cluster assumptions would be different.

Certain aspects of the present disclosure are directed to resolving this ambiguity in Tx-Rx UE distance determination for HARQ feedback purposes. For example, the Rx UE may take additional measures when computing distance based on a received zone ID indication, to resolve the zone ID ambiguity issue described herein. For instance, for the zones sharing the same zone ID indication, the Rx UE may select the zone closest to itself, and the Tx-Rx distance may be determined as the distance between Rx UE and the zone having the indicated zone ID that is closest to the Rx UE.

In certain aspects, the Rx UE computes multiple distances between the Rx UE (e.g., based on Rx UE's zone ID or coordinates, as described herein with respect to <FIG>) and multiple zones having the same zone ID indication. For the multiple zones having the same zone ID indication, at least one zone may be assumed to be in the same zone cluster (e.g. zone cluster <NUM>) in which the Rx UE is located, and at least one zone may be assumed to be in a different zone cluster as the Rx UE. The Rx UE selects the smallest distance from the multiple distances, and determines if HARQ feedback should be transmitted based at least on the smallest distance. As one example, the Rx UE may determine a distance <NUM> assuming the Tx UE is in zone <NUM> of zone cluster <NUM>, and a distance <NUM> assuming the Tx UE is in zone <NUM> of zone cluster <NUM>. For HARQ feedback, the UE may use the minimum of the calculated distances <NUM>, <NUM>.

<FIG> illustrate nine zone clusters, in one of which an Rx UE is located, and eight of which surround (e.g., are adjacent to) the zone cluster the Rx UE is located, in accordance with certain aspects of the present disclosure. As illustrated, the number of zones in a zone cluster is Nx*Ny. In this example, Nx = Ny = <NUM><NUM> = <NUM>. The Rx UE may determine (x, y) from its geographical coordinates, as described herein. Based on (x, y), the Rx UE determines the zone ID of the zone <NUM> the Rx UE is located. For example, the Rx UE zone ID may be equal to <NUM> (e.g., x<NUM> = <NUM>, y<NUM> = <NUM>). The Rx UE also receives the Tx UE's zone ID indication, as described herein. In the example illustrated in <FIG>, the zone ID is equal to <NUM> (e.g., x<NUM> = <NUM>, y<NUM> = <NUM> for Tx UE). The zone ID of <NUM> corresponds to any of the zones <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in the nine zone clusters illustrated in <FIG>. Thus, the Rx UE may compute <NUM> distances assuming the Tx UE is in each of the nine zones. One of the distances is based on the assumption that Tx UE is in the same zone cluster <NUM> as the Rx UE, and the other <NUM> distances are assuming that Tx UE is in the <NUM> surrounded zone clusters. The UE may then use the minimum of the calculated distances (e.g., distance <NUM>). Assuming that Tx-Rx distance is the distance of centers of two zones (e.g., as described with respect to <FIG>), the distance may be expressed either in meters, or by number of zones.

As described herein, a zone may be expressed by coordinates (x<NUM>, y<NUM>) (e.g., expressed by zone location within a zone cluster). For determining the Rx UE zone location, the Rx UE may first map the zone coordinates in a zone cluster to a massive zone cluster <NUM> (e.g., including <NUM> zone clusters). For example, the Rx UE may translate the Rx UEs zone coordinates as follows: (x<NUM>,Rx, y<NUM>,Rx) → (Nx + x<NUM>,Rx, Ny + y<NUM>,Rx). For the Rx UE, (Nx + x<NUM>,Rx, Ny + y<NUM>,Rx) corresponds to a zone in the center zone cluster <NUM> in the massive zone cluster <NUM>.

For Tx UE zone location, the Rx UE may map the zone coordinates of the indicated zone ID from the Tx UE as follows: <MAT> where (X, Y) has <NUM> possibilities: (<NUM>,<NUM>), (Nx, <NUM>), (2Nx, <NUM>), (<NUM>, Ny), (Nx, Ny), (2Nx, Ny), (<NUM>,2Ny), (Nx, 2Ny), (2Nx, 2Ny). Each of the nine possibilities for (X, Y) correspond to an assumption that the Tx UE is in one of the nine zones of the massive zone cluster <NUM>.

The Rx UE then computes <NUM> distance values between (Nx + x<NUM>,Rx, Ny + y<NUM>,Rx) and (X + x<NUM>,Tx, Y + y<NUM>,Tx). The distance may be computed as: <MAT> (in meters); or <MAT> (in number of zones)
where dx = (Nx + x<NUM>,Rx) - (X + x<NUM>,Tx), dy = (Ny + y<NUM>,Rx) - (Y + y<NUM>,Tx). The Rx UE then selects the smallest distance as the Tx-Rx UE distance for HARQ feedback determination.

Certain aspects of the present disclosure are directed to a wraparound distance determination technique. For example, the Rx UE may determine distances (denoted by dx and dy) between the Rx UE zone and the indicated Tx UE zone in longitude and latitude (or, in x-axis and y-axis, also referred to herein as "dimensions"), respectively. To determine each of the distances (e.g., dx), the Rx UE computes two distance values, one based on received zone ID directly (|x<NUM>,Rx - x<NUM>,Tx|), and another one based on received zone ID assuming wraparound (Nx - |x<NUM>,Rx - x<NUM>,Tx|). The Rx UE then selects the smaller value from the two distance values (e.g., dx = min(|x<NUM>,Rx - x<NUM>,Tx|, Nx - |x<NUM>,Rx - x<NUM>,Tx|)) The Rx UE then computes the Tx-Rx distance from the determined distances (dx and dy). For example, the Tx-Rx distance may be expressed either in meters, or by number of zones based on the following equations: <MAT> (in meters) <MAT> (in number of zones).

As an example, the Rx UE may first determine (x, y) from its geographical coordinates. Based on (x, y), the Rx UE determines its zone ID. For example, assuming the Rx UE and Tx UE locations illustrated in <FIG>, zone ID of the zone in which the Rx UE is located may be <NUM> corresponding to zone <NUM> for the Rx UE (e.g., x<NUM>,Rx = <NUM>, y<NUM>,Rx = <NUM>). The Rx UE also receives Tx UE's zone ID indication. For example, the zone ID may be <NUM> (e.g., x<NUM>,Tx =<NUM>, y<NUM>,Tx = <NUM> for Tx UE in zones <NUM>, <NUM>, <NUM>). The Rx UE then determines the distance (e.g., denoted by dx and dy) between Rx UE zone and received Tx zone in longitude and latitude (or, in x-axis and y-axis), as follows: <MAT> <MAT> The Tx-Rx distance between two UEs are then determined based on the following equations: <MAT> (in meters) <MAT> (in number of zones).

As described herein, the Tx UE may indicate a zone ID to the Rx UE. In some cases, the indication of the zone ID may be a jointly encoded parameter zone ID (e.g., ZoneID = y<NUM>Nx + x<NUM>). In other cases, the indication of the zone ID may be an indication of the parameters x<NUM> and y<NUM>, as described herein.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for distance-based HARQ signaling. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> (e.g., an example of means for) for monitoring; code <NUM> (e.g., an example of means for) for receiving, code <NUM> (e.g., an example of means for) for determining, and code <NUM> (e.g., an example of means for) for transmitting. One or more of code <NUM>, <NUM>, <NUM>, <NUM> may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device. In certain aspects, the processor <NUM> executes the code stored in the computer-readable medium/memory <NUM>. In certain aspects, computer-readable medium/memory <NUM> is an example of a HARQ manager <NUM>.

In certain aspects, alternatively or additionally, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> (e.g., an example of means for) for monitoring; circuitry <NUM> (e.g., an example of means for) for receiving; circuitry <NUM> (e.g., an example of means for) for determining; and circuitry <NUM> (e.g., an example of means for) for transmitting.

One or more of circuitry <NUM>, <NUM>, <NUM>, <NUM> may be implemented by one or more of a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device. In certain aspects, processor <NUM> is an example of a HARQ manager <NUM>.

The transceiver <NUM> may provide a means for receiving information. Information may be passed on to other components of the device <NUM>. The transceiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>. The antenna <NUM> may correspond to a single antenna or a set of antennas. The transceiver <NUM> may provide means for transmitting signals generated by other components of the device <NUM>.

The HARQ manager <NUM> may support wireless communication in accordance with examples as disclosed herein.

The HARQ manager <NUM> may be an example of means for performing various aspects described herein. The HARQ manager <NUM>, or its sub-components, may be implemented in hardware (e.g., in uplink resource management circuitry). The circuitry may comprise of processor, digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

In another implementation, the HARQ manager <NUM>, or its sub-components, may be implemented in code (e.g., as uplink resource management software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the HARQ manager <NUM>, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device.

In some examples, the HARQ manager <NUM> may be configured to perform various operations (e.g., receiving, determining, transmitting) using or otherwise in cooperation with the transceiver <NUM>.

The HARQ manager <NUM>, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the HARQ manager <NUM>, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the HARQ manager <NUM>, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein, for example, instructions for performing the operations described herein.

Claim 1:
A method for wireless communication by a user-equipment, UE, comprising:
monitoring (<NUM>) for a data transmission from another UE;
receiving (<NUM>) an indication of a first zone identifier, ID;
determining (<NUM>) a nearest zone to the UE of multiple zones, wherein the multiple zones are determined based at least in part on the indication of the first zone ID;
determining (<NUM>) a distance between the UE and the other UE based on the first zone ID, wherein the determined distance comprises a distance between the UE and the nearest zone; and
transmitting (<NUM>) hybrid automatic repeat request, HARQ, feedback for the data transmission based at least on the distance.