Patent Description:
<NPL>, relates to a discussion on identification during ProSe Direct Communication. <NPL>, relates to a discussion of different aspects of addresses and identifiers used for D2D/ProSe communication. <CIT> relates to a method of transmitting and receiving device-to-device signal in device-to-device communication and an apparatus therefor.

Aspects of wireless communication may comprise direct communication between devices, such as in V2X, V2V, and/or D2D communication. There exists a need for further improvements in V2X, V2V, and/or D2D technology.

Further embodiments are specified by the dependent claims. In the following, each of the described methods, apparatuses, examples, and aspects which does not fully correspond to the invention as defined in the claims is thus not according to the invention and is, as well as the whole following description, present for illustration purposes only or to highlight specific aspects or features of the claims.

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

The base stations <NUM> configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links <NUM> (e.g., S <NUM> interface). The base stations <NUM> configured for NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with Core Network <NUM> through backhaul links <NUM>. The base stations <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or Core Network <NUM>) with each other over backhaul links <NUM> (e.g., X2 interface).

For example, the small cell <NUM>' may have a coverage area <NUM>' that overlaps the coverage area <NUM> of one or more stations <NUM>, such as macro base stations. A network that includes both small cell and macro cells may be known as a heterogeneous network. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

A base station <NUM>, whether a small cell <NUM>' or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station. Some base stations <NUM>, such as a gNB, may operate in a traditional sub <NUM> spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE <NUM>. When the gNB operates in mmW or near mmW frequencies, the gNB may be referred to as an mmW base station. The base station <NUM>, e.g., a mmW base station, may utilize beamforming <NUM> with the UE <NUM> to compensate for the extremely high path loss and short range.

Devices may use beamforming to transmit and receive communication. For example, <FIG> illustrates that a base station <NUM> may transmit a beamformed signal to the UE <NUM> in one or more transmit directions <NUM>'. Although beamformed signals are illustrated between UE <NUM> and base station <NUM>/<NUM>, aspects of beamforming may similarly may be applied by UE <NUM> or RSU <NUM> to communicate with another UE <NUM> or RSU <NUM>, such as based on V2X, V2V, or D2D communication.

The Core Network <NUM> may include a Access and Mobility Management Function (AMF) <NUM>, other AMFs <NUM>, a Session Management Function (SMF) <NUM>, and a User Plane Function (UPF) <NUM>. The AMF <NUM> is the control node that processes the signaling between the UEs <NUM> and the Core Network <NUM>.

The base station <NUM> provides an access point to the EPC <NUM> or Core Network <NUM> for a UE <NUM>.

Some wireless communication networks may include vehicle-based communication devices that can communicate from vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes such as a Road Side Unit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as a base station), and/or a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (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/V2X/V2I or other D2D communication, such as Proximity Services (ProSe), etc. Communication based on V2V, V2X, V2I, and/or D2D may also be transmitted and received by other transmitting and receiving devices, such as Road Side Unit (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>. Although the following description may provide examples for V2X/D2D communication in connection with <NUM> NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Referring again to <FIG>, in certain aspects, a transmitting device, for example, a UE <NUM> communicating using V2V/V2X/D2D communication, may determine a source ID for communication over a link, determine a destination ID for the communication over the link. The UE <NUM> may comprise a link ID component <NUM> configured to determine a link ID for the communication over the link as a function of the source ID and the destination ID, and transmit a control message over the link, where the control message comprises the link ID. In certain aspects, a receiving device, for example, UE <NUM>, may receive the control message over the link, where the control message comprises the link ID as a function of the source ID and the destination ID for communication over the link. The UE may comprise a determination component <NUM> configured to determine whether to attempt to decode the data message received over the link based on the link ID received in the control message.

<FIG> illustrates example diagrams <NUM> and <NUM> illustrating examples slot structures that may be used for wireless communication between UE <NUM> and UE <NUM>', e.g., for sidelink communication. The slot structure may be within a <NUM>/NR frame structure. Although the following description may be focused on 5GNR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. This is merely one example, and other wireless communication technologies may have a different frame structure and/or different channels. Diagram <NUM> illustrates a single slot transmission, e.g., which may correspond to a <NUM> transmission time interval (TTI). Diagram <NUM> illustrates an example two-slot aggregation, e.g., an aggregation of two <NUM> TTIs. Diagram <NUM> illustrates a single RB, whereas diagram <NUM> illustrates N RBs. In diagram <NUM>, <NUM> RBs being used for control is merely one example. The number of RBs may differ.

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

<FIG> is a block diagram <NUM> of a first wireless communication device <NUM> in communication with a second wireless communication device <NUM>, e.g., via V2V/V2X/D2D communication. The device <NUM> may comprise a transmitting device communicating with a receiving device, e.g., device <NUM>, via V2V/V2X/D2D communication. The communication may be based, e.g., on sidelink. The transmitting device <NUM> may comprise a UE, an RSU, etc. The receiving device may comprise a UE, an RSU, etc. Packets may be provided to a controller/processor <NUM> that implements layer <NUM> and layer <NUM> functionality.

In some configurations, the UE <NUM> (e.g., vehicle) may operate in a half-duplex mode where the UE <NUM> may only either transmit or receive at a given time. The half-duplex mode operation may be due to a given deployment scenario (e.g., such as when performing V2X and/or V2V communications) that may desire a half-duplex operation by devices, or due to UE capability (e.g., such as where the UE <NUM> may have a single TX/RX chain (354TX/RX). In such configurations where the UE <NUM> may operate in the half-duplex mode, the UE <NUM> may not perform simultaneous transmission and reception.

At least one of the TX processor <NUM>, the RX processor <NUM>, or the controller/processor <NUM> of device <NUM> or the TX <NUM>, the RX processor <NUM>, or the controller/processor <NUM> may be configured to perform aspects described in connection with <NUM> and/or <NUM> of <FIG>.

<FIG> illustrates a diagram <NUM> of an example of signaling between devices, for example, UEs (e.g., UEs <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). In one aspect, a transmitting device, for example, a transmitting UE <NUM>, which may be comprised in a vehicle, may communicate based on V2V, V2X, or D2D communication. The communication may be based on <NUM>/NR, as an example. Such V2V/V2X/D2D communication may involve the transmission of information from a first vehicle, e.g., UE <NUM>, that is received directly by another vehicle, e.g., any of UEs <NUM>, <NUM>, <NUM>, or <NUM>. The communication may be intended for a single vehicle, e.g., unicast communication. In another example, the communication from the first UE <NUM> may be directed to a group of UEs, e.g., a subset from among UEs <NUM>, <NUM>, <NUM>, <NUM>. In yet another example, the communication may be broadcast to any vehicle within receiving range of the first UE <NUM>. Transmitting devices may need to provide some identifying information so that the receiving vehicles may determine whether to attempt to decode the communication.

In V2X, V2V, or D2D communication with a distributed transmission and connection establishment procedure for example, a transmitting UE and a receiving UE may determine identifier information to include in the transmission. A layer <NUM> ID (L2 ID), for example, may depend on one or more of application ID, UE ID, or a group ID. For example, the L2 ID may change over time for security. The L2 ID may comprise a number of bits, e.g., <NUM> bits. The signaling of the transmitting/receiving L2 ID may be split over multiple transmissions. As an example, the L2 ID may be split over a control message and a data transmission, so that a portion of the number of bits is sent in a control message and another portion of the number of bits is sent in a data message. In this disclosure, the terminology "Link ID" may be used to refer to the subset of information bits that are indicated in a control message. The information bits may indicate a destination ID and/or a source ID. It may be desirable to have the portion of the identifier bits that are included in control messages be small in order to reduce the required control overhead. As one example, the length of the Link ID may include, e.g., around <NUM> bits of the <NUM> bits of a L2 ID.

The receiving device may use the identifier information signaled in a control message (e.g., link ID) to determine how to handle corresponding data messages. For example, the receiving device may use the identifier information to determine whether the receiving device should decode the data, whether and how to combine the received data over multiple HARQ (re)transmissions previously received from the transmitting device, whether or not to provide NACK feedback to the transmitting device if the control message is received but not the data message, and/or to determine a scrambling sequence for such feedback.

Aspects presented herein enable the transmitting device and the receiving device to communicating using a link ID that has a unified structure that can be applicable to the various types of communication in a <NUM>/NR V2X/V2V communication system, e.g., unicast communication, multicast communication, and broadcast communication.

As presented herein, the transmitting and receiving devices may determine a source ID for communication over a link, determine a destination ID for the communication over the link, and transmit a control message <NUM> over the link, where the control message <NUM> indicates the destination ID and the source ID. For example, the transmitting device may determine a link ID <NUM> for the communication over the link as a function of the source ID and the destination ID. The control message may comprise the link ID <NUM>. For example, the transmitting UE may further transmit a data message <NUM> associated with the control message.

In the example illustrated in <FIG>, a receiving UE <NUM> may receive the control message <NUM> over the link, where the control message indicates a source ID and a destination ID (e.g., the control message may comprise the link ID <NUM> as a function of the source ID and the destination ID) for communication over the link. The receiving device/UE <NUM> may further receive the data message <NUM> over the link, and determine whether to attempt to decode the data message <NUM> received over the link based on the link ID <NUM> received in the control message <NUM>. For example, the transmitting UE <NUM> may communicate with the receiving UE <NUM> using V2X communication or V2V communication. For example, the link ID may comprises a unified link ID for unicast, multicast, and broadcast communication.

The identifier information (such as the link ID) signaled in the control message may enable the receiving UE to determine whether and how to combine the received data over multiple HARQ (re)transmissions previously received from the transmitting device. For example, the link ID may enable the receiving device to identify whether the received data is a retransmission from the same transmitting device from which the UE received a prior transmission and the same HARQ process as the prior received transmission, in which case the UE may decide to employ HARQ combining for decoding the received data. As another example, a link ID having a different source ID (i.e. sent by a different transmitting device) but still addressed to the receiving UE. Even if the received transmission has a and matching a HARQ process ID with a previously received data the different source ID indication in the link ID, may enable the receiving UE to know that this data cannot be combined from a previously received data because it was sent by a different transmitting device.

The identifier information (such as the link ID) signaled in the control message may be utilized by the receiving UE to determine a feedback. For example, the receiving UE may determine whether or not to decode the data. For this purpose, the link ID may indicate a destination ID. As another example, the receiving UE may determine whether or not to send a NACK when the control message is received but the data transmission is not received. For this purpose, the link ID may similarly indicate the destination ID. As yet another example, the receiving UE may determine a scrambling sequence to scramble the feedback (ACK/NACK). For this purpose, the link ID may indicate a source ID. The link ID presented herein can be signaled in the control message and may be used at the receiving UE to filter data transmissions and provide feedback. Further, aspects presented herein enable a unified link ID design to support unicast, multicast (for NACK-based multicast), broadcast transmissions.

In LTE D2D based communication, the physical layer may be based on broadcast without feedback. For D2D, a control message might include a destination ID signaled in the control message, and the rest of a L2 ID bits may be transmitted in data MAC header. Furthermore, to enable HARQ combining over blind (i.e. non-feedback based) (re)transmission of data, an implicit resource linkage between the transmissions and (re)transmissions of a data packet may be employed. In LTE based V2X, similar to D2D, the physical layer may be broadcast without a need for feedback. Without a Link ID being signaled in control messages, e.g., for LTE V2X, all UEs may be expected to decode all received messages. These example may not be able to meet the needs of NACK based multicast or unicast communication directly between UEs. Furthermore, such designs may lead to inefficiencies by requiring UEs to decode all received communication.

In contrast to LTE D2D and LTE V2X communication, V2X/V2V/D2D communication based on NR may support unicast, broadcast, and/or multicast communications coexisting using a same resource pool. Thus, aspects presented herein provide a common control message design that is capable of supporting the unicast, broadcast, and multicast communication.

As presented herein, V2X, V2V, or D2D communication may include a control message that indicates a source ID and a destination ID for communication over a link. A link ID may be included in the control message communicated over the link and may be a function of both the source ID and the destination ID for communication over the link.

For unicast communication, the destination ID may correspond to an ID for the receiving device, and the source ID may correspond to an ID for the transmitting device. Thus, the link ID may be based, at least in part, on the receiving UE's ID. From the link ID, the receiving UE may determine whether or not the transmission is meant for the receiving UE. Unicast communication may involve feedback from the receiving UE, whether ACK or NACK, to let the transmitting device know whether the control message and/or a corresponding data message are received by the receiving UE. The receiving UE may also use the link ID to determine the scrambling sequence for providing feedback to the transmitting UE. When the receiving UE uses the scrambling sequence for feedback, the transmitting UE also knows the scrambling sequence that the receiving UE will use to scramble the feedback because the transmitting device provided the link ID to the receiving device. The feedback and/or scrambling sequence may be further based on a location, which may be known as a function of the transmission resource. As the link ID depends on the source ID, the link ID may help to avoid feedback collisions to other transmitting UEs. As well, by scrambling the feedback based on a link ID that is a function of the source ID (e.g., transmitting UE ID), the transmitting device may determine that the feedback is intended for it as the source of the control/data message for which feedback is provided. As well, as the link ID may be a function of the destination ID (e.g., receiving UE ID), the transmitting device is able to identify the UE from which it receives the feedback. Further, a link ID comprising in part the source ID and in part the destination ID, may enable a receiving UE to determine whether and how to combine the received data over multiple HARQ (re)transmissions previously received from the transmitting device (source ID).

For broadcast communication, a group ID/destination ID, which may be determined by upper layers, may be sufficient. The group ID/destination ID may enable receiving UEs to filter out received packets based on the link ID present in the control message. Feedback might not be needed for broadcast communication. The inclusion of the source ID in the link ID may enable a receiving UE to identify the source of the data (e.g., from a group of transmitting UEs). The source of the data may be helpful in performing HARQ combining of the received data from a given source ID, e.g., if blind (non-feedback based) HARQ (re)transmission of broadcast data transmission is supported.

For multicast communication, specifically, NACK-based multicast communication, when a control message is received from a transmitting UE, the receiving UE may need to determine whether or not to provide NACK feedback when corresponding data is not received. Basic safety messages (BSMs), for example, LTE V2X-based BSMs, may be used to determine the UEs present in an area. A receiving UE may determine whether or not to provide feedback depending on the location of the transmitting UE (e.g., which may be determined from the BSM) and a desired range. The BSM may have a corresponding range of interest surrounding the transmitting UE. If the receiving UE is not within the range of interest, e.g., not within an indicated distance of the transmitting UE, the receiving UE may determine not to provide feedback. If the UE is within the range and receives the control message without receiving the corresponding data, the UE may determine to provide feedback. The range of interest corresponding to the BSM may be determined by higher layers of the transmitting UE and may be indicated to receiving UEs in the control message. To enable NACK based multicast, a connection or relationship may be needed between an ID used in a BSM and another link ID used in the multicast V2X message.

As one example, the transmitting UE may send a station ID (specific to the transmitting UE) in a BSM message. The station ID may be an application layer ID used for BSM messages. A link ID, which may be a function of the station ID may be derived to use in the transmission of multicast V2X message. In the control message of the multicast V2X message, indicate a token ID, which may be a function of the station ID, may be indicated. A receiving UE may have a list of station IDs, from the BSM(s), for which the receiving UE is required to NACK if the receiving UE receives the control message and does not receive the data transmission. The receiving UE may monitor a list of token IDs, which are function of the list of station IDs, to determine whether to provide NACK feedback. However, such an approach may require a source ID to be present in the control message. For other V2X operations, e.g., unicast messaging, it may be more appropriate for a destination ID to be present in the control message. For example, the receiving UEs may then determine whether or not the message is meant for the receiving UEs and proceed to receive/decode the message and/or determine whether to send NACK, if the message is not accurately received. Having both source and destination IDs (full IDs or function of the IDs, e.g., n-LSBs) may increase the control payload.

Aspects presented herein provide a link ID that meets the unique needs of each of NACK-based multicast communication, unicast communication, and broadcast communication in a unified manner. As well, aspects presented herein avoid a need for a linkage between an application layer station ID and a RAN layer <NUM> ID used in the transmission. The link ID may be a function of both a source ID and a destination ID. For unicast communication, a transmitting UE ID may be used for the source ID and a receiving UD ID may be used for the destination ID. For broadcast communication, in one case, a broadcast group ID may be used for both the source ID and the destination ID. For broadcast communication, in another case, a broadcast group ID may be used for the destination ID and the transmitting UE ID may be used for the source ID. For multicast communication, a station ID (e.g., an application layer ID) may be used for the source ID and a group ID may be used for the destination ID. For example, the station ID may be an application layer ID that the transmitting UE uses for BSMs. For example, a hash map function of the source ID and the destination ID may be used to generate the link ID.

<FIG> is a diagram <NUM> illustrating a link design in a wireless communication between a transmitting UE <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>) and a receiving UE (e.g., <NUM>', <NUM>, <NUM>, <NUM>). The wireless communication may comprise V2X, V2V, or D2D communication. As an example, the wireless communication may be based on NR. Optional aspects are illustrated in dash lines. The transmitting UE <NUM> and the receiving UE <NUM> may each be comprised in a vehicle or a device positioned in a vehicle in a V2V/V2X network. In other examples, aspects may be performed by other devices communicating based on V2V, V2X, or D2D communication. For example, a RSU or other device. The transmitting UE <NUM> may communicate directly with the receiving UE <NUM> over a communication link including transmitting both control messages and data messages. The control messages may include a link ID that enables the receiving UE <NUM> to determine whether to decode the corresponding data message, whether to provide feedback, etc. The link ID may be based on both a source ID and a destination ID, and thus may indicate the destination ID and the source ID. Thus, the transmitting device may determine a source ID for communication over the link, as illustrated at <NUM>, and may determine a destination ID for the communication over the link, as illustrated at <NUM>. The determination of the source ID and/or the destination ID may be based on the type of communication transmitted by the transmitting UE <NUM>, e.g., whether the UE <NUM> is transmitting unicast communication, multicast communication, or broadcast communication. For example, for unicast communication, the source ID may comprise a data link layer ID for the transmitting UE and the destination ID may comprise a data link layer ID for the receiving UE. For broadcast communication, in one case, the source ID may be the same as the destination ID, and the same as the broadcast group ID. For broadcast communication, in another case, a broadcast group ID may be used for the destination ID and the transmitting UE ID may be used for the source ID. For multicast communication, the source ID may be the station ID, which may be the application layer ID that the transmitting UE uses for BSM message, and the destination ID may be the group ID. When the transmitting UE <NUM> and the receiving UE <NUM> are running a multicast application, the UEs running the multicast application may determine a group ID (in the V2X layer) based on a (pre)configuration. For example, the application ID may be mapped to the group ID. The group ID may apply to all transmitting UEs and receiving UES running this multicast V2X application session.

Once the transmitting UE has determined the source ID and the destination ID, the transmitting UE <NUM> may determine a link ID <NUM> for the communication over the link as a function of the source ID and the destination ID, as illustrated at <NUM>. For example, the link ID may generated using a hash map function of a combination of the source ID and the destination ID to the link ID. For example, the hash map function may reduce a first number of bits of the combination of the source ID and the destination ID to a second number of bits for the link ID, where the second number of bits is smaller than the first number of bits. The transmitting UE <NUM> may transmit a control message <NUM> over the link, where the control message <NUM> comprises the link ID <NUM>. For example, the transmitting UE may further transmit a data message <NUM>. The data message may include further identifying information, such that the link ID comprises a portion of identifying information and the data message comprises another portion of identifying information for the communication. The link ID, determined at <NUM> for inclusion in the control message <NUM>, may comprises a unified link ID design for unicast, multicast, and broadcast communication.

The receiving UE <NUM> may receive the control message <NUM> over the link, where the control message <NUM> comprises the link ID <NUM> as a function of the source ID and the destination ID for communication over the link. The receiving UE may use the link ID to determine the source ID and/or the destination ID, e.g., to determine whether communication with the link ID pertains to the receiving UE. The receiving UE <NUM> may further receive the data message <NUM> over the link, and may determine whether to attempt to decode the data message <NUM> received over the link based on the link ID <NUM> received in the control message <NUM>. The receiving UE <NUM> may also use the source ID and/or destination ID information in the link ID of the control message <NUM> to determine whether to provide feedback to the transmitting UE <NUM>.

For example, the receiving UE <NUM> may receive multicast communication, such as a plurality of Basic Safety Messages (BSMs) <NUM>. The receiving UE <NUM> may determine whether to send a feedback <NUM> for each of the plurality of BSMs <NUM> based on at least one of a location of the receiving UE <NUM>, a range for a particular BSM message, or a Quality of Service for the particular BSM message. As the link ID for multicast communication may include a station ID as a source ID, the receiving UE <NUM> may determine a station ID for each BSM from the plurality of BSMs. The UE may determine whether to send feedback for each of the BSMs, e.g., based on any of the station ID for a particular BSM, the desired range for the particular BSM, the location of the receiving UE, QoS for the particular BSM, etc. The UE may generate and maintain a first list of station IDs for which the receiving UE determines to send feedback <NUM>, as illustrated at <NUM>.

For example, the receiving UE <NUM> may determine the link ID <NUM> based on the group ID and the station ID for each station ID in the list of station IDs, and maintain a second list of the data link layer IDs for the transmitting UEs for which the receiving UE <NUM> determines to send the feedback, at <NUM>. The second list of the data link layer IDs may be determined as a function of the group ID and the station ID for multicast V2X messages. Then, the receiving UE <NUM> may determine whether to send feedback <NUM> to the transmitting UE <NUM> based on whether the link ID <NUM> received in the control message <NUM> is in the second list of link IDs maintained at the receiving UE <NUM>. The receiving UE may send feedback <NUM> to the transmitting UE <NUM> when the link ID <NUM> received in the control message <NUM> is in the second list of link IDs maintained at the receiving UE <NUM>. The feedback may comprise a NACK when the receiving UE <NUM> receives the control message <NUM>, but does not receive the data transmission <NUM>.

The receiving UE <NUM> may scramble the feedback, at <NUM>, using a scrambling sequence as a function of at least one of the link ID for the link or a station ID for the corresponding BSM, prior to transmitting the feedback at <NUM>. If a V2X/V2V/D2D multicast control message <NUM> is received that corresponds to the second list of the transmitting link IDs, for which the receiving UE <NUM> wishes to send NACK, and the UE fails to receive the data transmission <NUM>, the receiving UE <NUM> may scramble the NACK feedback at <NUM> using a scrambling sequence as a function of the transmitting link ID or a station ID for the corresponding BSM. Then, the UE may transmit the scrambled NACK at <NUM>.

For example, the scrambling sequence may be further based on a cyclic redundancy check (CRC) of the control message <NUM>. In one aspect, the scrambling sequence may be determined based on a function of at least one of the link ID for the link or a station ID for the corresponding BSM, and further based on the CRC of the control message <NUM>. This approach provides further randomization when there is collision of one or more subchannels being used by different transmitting UEs.

The link ID disclosed herein provides a unified link ID that meets the individual needs of NACK based multicast communication, unicast communication and broadcast communication. The link ID may comprise a hash function of the source ID and destination ID, e.g., for NACK based multicast communication. Furthermore, the link ID design enables receiving UE to filter the messages at a MAC layer. For example, the receiving UE may filter out messages for which the receiving UE is not a part of the intended group. Such filtering may help the UE to avoid decoding messages that do not pertain to the UE. The use of a destination ID along with a source ID to generate the link ID enables a UE to distinguish between messages sent to different groups by the same transmitting UE. For example, a transmitting UE, using a same station ID, may transmit messages to two or more groups, and a given receiving UE may only be a part of one of the groups. Through the link ID presented herein, the receiving UE will be able to filter out the messages from the transmitting UE for groups that do not apply to the receiving UE.

<FIG> is a flowchart <NUM> of a method of wireless communication at a transmitting UE. The method may be performed, for example, by the transmitting UE (e.g., UE <NUM>, <NUM>, <NUM>, <NUM>, the apparatus <NUM>/<NUM>', processing system <NUM>, which may include memory and which may be an entire UE or a component of a UE, e.g., including any of TX processor <NUM>, RX processor <NUM> and/or controller/processor <NUM>) communicating with a receiving UE (e.g., UE <NUM>', <NUM>, <NUM>) in a wireless communication. The wireless communication may comprise V2X, V2X, or other D2D communication. The transmitting UE may comprise a vehicle or a device installed in a vehicle. To facilitate an understanding of the techniques and concepts described herein, the method of flowchart <NUM> may be discussed with reference to the examples illustrated in <FIG> and <FIG>. Optional aspects may be illustrated in dashed lines.

At <NUM>, the transmitting UE may determine a source ID for communication over a link. The determination may be based, in part, on whether the communication is unicast, broadcast, or multicast communication. The source ID may be determined by source ID component <NUM> of apparatus <NUM>, for example.

At <NUM>, the transmitting UE may determine a destination ID for the communication over the link. Similar to the source ID, the destination ID may be determined, in part, based on the type of communication that the transmitting UE intends to transmit, e.g., based on whether the communication will be unicast, broadcast, or multicast. The destination ID may be determined by destination ID component <NUM> of apparatus <NUM>, for example.

For example, for unicast communication, the source ID may comprise a data link layer ID for the transmitting UE and the destination ID may comprise a data link layer ID for the receiving UE. As another example, for broadcast communication, the source ID may be the same as the destination ID, and the source ID and the destination ID both comprise a broadcast group ID. As another example, for multicast communication, the source ID may be the station ID, which may be the application layer ID that the transmitting UE uses for BSM message, and the destination ID may be the group ID.

At <NUM>, the transmitting UE may determine a link ID for the communication over the link as a function of the source ID and the destination ID. For example, link ID component <NUM> of apparatus <NUM> may determine the link ID. The function may comprise a hash map function of a combination of the source ID and the destination ID to the link ID, as illustrated at <NUM>. Thus, the link ID may be generated using a hash map function based on the determined source ID and the determined destination ID for the communication. For example, the hash map function may reduce a first number of bits of the combination of the source ID and the destination ID to a second number of bits for the link ID, where the second number of bits is smaller than the first number of bits.

When the transmitting UE and the receiving UE are running a multicast application, the UEs running the multicast application may determine a group ID (in the V2X layer) based on a configuration. For example, the application ID may be mapped to the group ID. The group ID may apply to all transmitting UEs and receiving UES running this multicast V2X application session.

At <NUM>, the transmitting UE may transmit at least one control message over the link, where the control message(s) indicate the source ID and the destination ID. For example, the control message may be transmitted by control message component <NUM> and/or transmission component <NUM> of apparatus <NUM>. As an example, the control message may comprise a link ID. The link ID may comprise a unified link ID for unicast, multicast, and broadcast communication. As illustrated in <FIG>, the transmitting UE may also transmit data, e.g., <NUM>, associated with the control message (e.g., <NUM>). Based on the type of communication, the transmitting UE may also receive feedback from the receiving UE, e.g., <NUM>. The feedback may be received, e.g., by reception component <NUM> of apparatus <NUM>. The feedback may be scrambled based on the link ID. Thus, the transmitting UE may determine whether the received feedback is intended for the transmitting UE and/or the source of the feedback based on the link ID used to scramble the feedback. The feedback may comprise, e.g., a NACK indicating that the receiving UE did not receive the data. The transmitting UE may determine to retransmit the data based on the feedback.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM>. The apparatus may be a transmitting UE (e.g., UE <NUM>, <NUM>, <NUM>, the apparatus <NUM>/<NUM>', <NUM>, etc.) communicating with a receiving UE (e.g., UE <NUM>', <NUM>, <NUM>, <NUM>, the apparatus <NUM>/<NUM>', etc.) in a wireless communication. The wireless communication may comprise a V2X or V2V communication, as described herein.

The apparatus includes a source ID component <NUM> configured to determine the source ID for communication over a link, e.g., as described in connection with <NUM> in <FIG>. The apparatus includes a destination ID component <NUM> configured to determine the destination ID for communication over a link, e.g., as described in connection with <NUM> in <FIG>. The apparatus may include a link ID component <NUM> configured to determine a link ID for the communication over the link as a function of the source ID and the destination ID, e.g., as described in connection with <NUM> in <FIG>.

The apparatus includes a transmission component <NUM> for transmitting data, control messages, etc. The apparatus includes a control message component <NUM> that transmits, via the transmission component <NUM>, a control messages over the link, where the control message indicates the source ID and the destination ID, e.g., as described in connection with <NUM> in <FIG>. The apparatus includes a data component <NUM> that transmits, via the transmission component <NUM>, data transmissions. The apparatus further includes a reception component <NUM> that receives feedback from receiving UEs regarding reception of the data transmission(s).

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium/memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium/memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium/memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. In one configuration, the processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. Alternatively, the processing system <NUM> may comprise the entire UE.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication may include includes means for determining a source ID for communication over a link. The apparatus may include means for determining a destination ID for the communication over the link. The apparatus may include means for determining a link ID for the communication over the link as a function of the source ID and the destination ID. The apparatus may include means for transmitting a control message over the link, where the control message that indicates the source ID and the destination ID.

<FIG> is a flowchart <NUM> of a method of wireless communication at a receiving UE. The method may be performed, for example, by the receiving UE (e.g., UE <NUM>', <NUM>, <NUM>, <NUM>, the apparatus <NUM>/<NUM>'; processing system <NUM> that may include memory and which may be an entire UE or a component of a UE) in a wireless communication. The wireless communication may comprise V2V, V2X, or D2D communication. The communication may be based on NR, for example. As an example, the receiving UE may be comprised in a vehicle or a device associated with a vehicle. To facilitate an understanding of the techniques and concepts described herein, the method of flowchart <NUM> may be discussed with reference to the examples illustrated in <FIG>. Optional aspects may be illustrated in dashed lines.

At <NUM>, the receiving UE may receive at least one control message over a link, where the control message(s) comprises an indication of a source ID and a destination ID. The control message may comprise a link ID as a function of the source ID and the destination ID for communication over the link. <FIG> describes an example of a control message <NUM> comprising a link ID. The reception of the control message may be performed by reception component <NUM> of apparatus <NUM>, for example.

At <NUM>, the receiving UE may further receive a data message over the link. The reception of the data message may be performed by reception component <NUM> of apparatus <NUM>, for example. The data message may be associated with the control message.

At <NUM>, the receiving UE may determine whether to attempt to decode the data message received over the link based on the source ID and/or the destination ID indicated in the control message(s). The source ID and the destination ID may be based on a type of the communication (e.g., whether the communication is unicast communication, multicast communication, or broadcast communication). For example, the determination may be performed by determination component <NUM> of apparatus <NUM>. As an example, the receiving UE may determine whether to attempt to decode the data message based on the link ID received in the control message. In some aspects, the link ID may comprise a unified link ID for unicast, multicast, and broadcast communication.

The link ID may be a function of the source ID and the destination ID, e.g., as described in connection with <FIG>, <FIG>, and <FIG>. The function may comprise a hash map function, such that the link ID is generated using a hash map function of a combination of the source ID and the destination ID for the communication. For example, the hash map function may reduce a first number of bits of the combination of the source ID and the destination ID to a smaller, second number of bits for the link ID.

In some aspects, for unicast communication, the source ID may comprise a data link layer ID for the transmitting UE and the destination ID may comprise a data link layer ID for the receiving UE.

In some aspects, for broadcast communication, the source ID may be the same as the destination ID, and the source ID and the destination ID both comprise a broadcast group ID.

In some aspects, for multicast communication, the source ID may be the station ID, which may be the application layer ID that the transmitting UE uses for BSM message, and the destination ID may be the group ID.

At <NUM>, for example, wherein the communication comprises multicast communication, the receiving UE may receive a plurality of BSMs. The reception may be performed by reception component <NUM> of apparatus <NUM>. At <NUM>, the receiving UE may determine whether to send a feedback for each of the plurality of BSMs based on at least one of a location of the receiving UE, a range for a particular BSM message, or a Quality of Service for the particular BSM message. The determination may be performed by determination component <NUM> of apparatus <NUM>, for example. At <NUM>, the receiving UE may determine a station ID for each BSM from the plurality of BSMs for which the receiving UE determines to send the feedback. For example, the station ID may be performed by station ID component <NUM> of apparatus <NUM>. At <NUM>, the receiving UE may maintain a first list of station IDs for which the receiving UE determines to send the feedback. For example, first list component <NUM> of apparatus <NUM> may maintain the list.

At <NUM>, the receiving UE may determine the link ID based on the group ID and the station ID for each station ID in the list of station IDs. For example, the link ID may be determined by link ID component <NUM> of apparatus <NUM>. At <NUM>, the receiving UE may maintain a second list of the data link layer IDs for the transmitting UEs for which the receiving UE determines to send the feedback. For example, the second list may be maintained by second list component <NUM> of apparatus <NUM>. At <NUM>, the receiving UE may determine whether to send feedback to the transmitting UE based on whether the link ID received in the control message is in the second list of link IDs maintained at the receiving UE.

At <NUM>, the receiving UE may send feedback to the transmitting UE when the link ID received in the control message is in the second list of link IDs maintained at the receiving UE. The feedback may be sent by transmission component <NUM> of apparatus <NUM>.

At <NUM>, the receiving UE may scramble the feedback using a scrambling sequence as a function of at least one of the link ID for the link or a station ID for the corresponding BSM. For example, the scrambling may be performed by scrambling component <NUM> of apparatus <NUM>. In some aspects, the scrambling sequence may be further based on a cyclic redundancy check (CRC) of the control message. As described in connection with <FIG>, the transmitting UE may use the feedback to determine whether the receiving UE successfully received the data and/or to determine whether to retransmit the data to the receiving UE.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM>. The apparatus may be a receiving UE or a component of a UE (e.g., UE <NUM>', <NUM>, <NUM>, <NUM>,) communicating with a transmitting UE (e.g., UE <NUM>, <NUM>, <NUM>, the apparatus <NUM>/<NUM>', the apparatus <NUM>, etc.) in a wireless communication. The wireless communication may comprise a V2X, V2V, or D2D communication, as described herein.

The apparatus includes a reception component <NUM> that receives a control message, data transmission and/or BSM messages over a link, where the control message comprises an indication of the source ID and the destination ID, e.g., as described in connection with <NUM>, <NUM>, <NUM> of <FIG>. The control message may comprise a link ID as a function of the source ID and the destination ID for communication over the link.

The apparatus includes a determination component <NUM> that determines, e.g., whether to attempt to decode a data message received over the link based on the source ID and destination ID indicated in the control message, e.g., as described in connection with <NUM> of <FIG>. In some aspects, the determination may be based on a link ID in the control message. The apparatus includes a decoding component <NUM> that decodes the data message based on the determination.

In some aspects, the reception component <NUM> may receive a plurality of BSMs. The determination component may further determine whether to send a feedback for each of the plurality of BSMs based on at least one of a location of the receiving UE, a range for a particular BSM message, or a Quality of Service for the particular BSM message.

The apparatus may include a station ID component <NUM> that determines a station ID for each BSM from the plurality of BSMs for which the apparatus determines to send the feedback, e.g., as described in connection with <NUM> of <FIG>. The apparatus may include a first list component <NUM> that maintains a first list of station IDs for which the determination component <NUM> determines to send the feedback, e.g., as described in connection with <NUM> in <FIG>.

The apparatus may include a link ID component <NUM> that determines the link ID based on the group ID and the station ID for each station ID in the first list of station IDs, e.g., as described in connection with <NUM> in <FIG>. The apparatus may include a second list component <NUM> that maintains a second list of the data link layer IDs for the transmitting UE for which the determination component <NUM> determines to send the feedback, e.g., as described in connection with <NUM> in <FIG>. The determination component <NUM> may determine whether to send feedback to the transmitting UE based on whether the link ID received in the control message is in the second list of link IDs, e.g., as described in connection with <NUM> in <FIG>.

The apparatus may include a transmission component <NUM> that sends feedback to the transmitting UEs when the link ID received in the control message is in the second list of link IDs, e.g., as described in connection with <NUM> in <FIG>.

The apparatus may include a scrambling component <NUM> that scrambles the feedback using a scrambling sequence as a function of at least one of the link ID for the link or a station ID for the corresponding BSM, e.g., as described in connection with <NUM> in <FIG>. In some aspects, the scrambling sequence may be further based on a cyclic redundancy check (CRC) of the control message.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium/memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium/memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium/memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. In one configuration, the processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. Alternatively, the processing system <NUM> may comprise the entire UE.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication includes means for receiving a control message over a link, where the control message comprises an indication of a source ID and a destination ID for communication over the link. The apparatus may include means for receiving a data message over the link and means for determining whether to attempt to decode the data message received over the link based on the source ID and the destination ID indicated in the control message. In some aspects, where the communication comprises multicast communication, the source ID comprising an application layer ID and the destination ID comprising a group ID for the multicast communication, the apparatus <NUM>/<NUM>' may further include means for receiving a plurality BSMs and means for determining whether to send feedback for each of the plurality of BSMs based on at least one of a location of the receiving device, a range for a particular BSM message, or a Quality of Service for the particular BSM message. The apparatus may include means for determining a station ID for each BSM from the plurality of BSMs for which the receiving device determines to send the feedback and means for maintaining a first list of station IDs for which the receiving device determines to send the feedback. The apparatus may include means for determining the link ID based on the group ID and the station ID for each station ID in the first list of station IDs; means for maintaining a second list of link IDs for which the receiving device determines to send the feedback; and means for determining whether to send feedback to the transmitting device based on whether the link ID received in the control message is in the second list of link IDs maintained at the receiving device. The apparatus may include means for sending feedback to the transmitting device when the link ID received in the control message is in the second list of link IDs maintained at the receiving device.

Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes/flowcharts may be rearranged.

Claim 1:
A method (<NUM>) of wireless communication at a transmitting device, the method (<NUM>) comprising:
determining (<NUM>) a source ID and a destination ID for a sidelink data transmission based on a type of communication of the sidelink data transmission being unicast communication, multicast communication, or broadcast communication, wherein the source ID is different for different types of communication of the unicast communication, the multicast communication, or the broadcast communication;
determining a link identifier for the sidelink data transmission, the link identifier being a hash map function of the source ID and the destination ID, wherein the hash map function reduces a first number of bits of a combination of the source ID and the destination ID to a second number of bits for the link identifier, the second number of bits being smaller than the first number of bits;
transmitting (<NUM>) at least one sidelink control message comprising the link identifier for the sidelink data transmission; and
transmitting the sidelink data transmission associated with the at least one sidelink control message.