Indication of the traffic direction of the sidelink

Abstract

Aspects of the present disclosure provide techniques for configuring device-to-device (D2D) communications for one or more user equipments (UEs) in New Radio (NR). Specifically, features of the present disclosure provide techniques for initial beam pairing for sidelink communications that optimize communication resources (e.g., a resource pool) by indicating the direction of traffic (e.g., transmit or receive) during the initial beam pairing process and establishing sidelink communications without requiring scheduling request transmissions between UEs.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 904,514, filed on September 23, 2019, entitled “INDICATION OF TRAFFIC DIRECTION FOR SIDELINK,” and U.S. Patent Application No. 17,011,615, filed on September 3, 2020, entitled “INDICATION OF TRAFFIC DIRECTION FOR SIDELINK,” the entireties of which are expressly incorporated herein by reference. Background Art

[0003] The present disclosure relates to wireless communication systems, and more particularly, to device-to-device (D2D) communication that indicates the direction of traffic during an initial access procedure.

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a municipal, national, regional, and even global level. For example, the fifth generation (5G) wireless communication technology, which may be referred to as New Radio (NR), is envisioned to expand and support a variety of usage scenarios and applications relative to current mobile network generations. In one aspect, 5G communication technology may include: enhanced mobile broadband that addresses human-centric use cases for accessing multimedia content, services, and data; ultra-reliable low latency communication (URLLC) with specific latency and reliability specifications; and massive machine type communication, which may allow for a large number of connected devices and the transmission of relatively small amounts of non-delay-sensitive information. However, as the demand for mobile broadband access continues to increase, further improvements in and beyond NR communication technology may be expected. Summary of the Invention

[0006] Aspects of the present disclosure provide techniques for configuring device-to-device (D2D) communications for one or more user equipments (UEs) in New Radio (NR). Specifically, features of the present disclosure provide techniques for initial beam pairing for sidelink communications that optimize communication resources (e.g., a resource pool) by indicating the direction of traffic (e.g., transmit or receive) during the initial beam pairing process and establishing sidelink communications without requiring scheduling request transmissions between UEs.

[0007] In one example, a method for wireless communication is disclosed. The method may include initiating an initial beam pairing procedure at a first user equipment (UE) to establish sidelink communication with a second UE. The method may also include determining whether the first UE is scheduled to send data or receive data from the second UE, or both. The method may also include identifying a direction of traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both. The method may also include sending a random access signal from the first UE to the second UE on a resource corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of the traffic.

[0008] In another example, an apparatus for wireless communication. The apparatus may include a memory having instructions and a processor configured to execute the instructions to initiate an initial beam pairing process at a first UE to establish sidelink communication with a second UE. The processor may also be configured to execute the instructions to determine whether the first UE is scheduled to send data or receive data from the second UE, or both. The processor may also be configured to execute the instructions to identify the direction of the traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both. The processor may also be configured to execute the instructions to send a random access signal from the first UE to the second UE on a resource corresponding to the beam synchronization control signal, wherein the random access signal includes information associated with the direction of the traffic.

[0009] In some aspects, a non-transitory computer-readable medium includes instructions stored therein that, when executed by a processor, cause the processor to perform steps of initiating an initial beam pairing procedure at a first UE to establish sidelink communication with a second UE. The processor may also execute instructions for determining whether the first UE is scheduled to transmit data or receive data from the second UE, or both. The processor may also execute instructions for identifying a direction of traffic based on determining whether the first UE is scheduled to transmit data or receive data from the second UE, or both. The processor may also execute instructions for sending a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of the traffic.

[0010] In certain aspects, another apparatus for wireless communication is disclosed. The apparatus may include means for initiating an initial beam pairing procedure at a first UE to establish sidelink communication with a second UE; means for determining whether the first UE is scheduled to transmit data, receive data from the second UE, or both transmit data or receive data from the second UE; means for identifying a direction of traffic based on determining whether the first UE is scheduled to transmit data, receive data from the second UE, or both transmit data or receive data from the second UE; and means for transmitting a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of the traffic.

[0011] To achieve the foregoing and related ends, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of only a few of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The disclosed aspects will hereinafter be described in conjunction with the accompanying drawings, which are provided to illustrate and not to limit the disclosed aspects, wherein like reference numerals represent like elements, and wherein:

[0013] Figure 1 is a schematic diagram of an example of a wireless communication system according to aspects of the present disclosure;

[0014] Figure 2 is a schematic diagram of an example of a wireless communication system implementing D2D communication according to aspects of the present disclosure;

[0015] Figure 3is a schematic diagram of an example implementation of various components of a user device according to various aspects of the present disclosure; and

[0016] Figure 4 is a flowchart of an example of a wireless communication method implemented by a UE according to aspects of the present disclosure. DETAILED DESCRIPTION

[0017] In recent years, with the introduction of a large number of smart handheld devices, users' demand for mobile broadband has increased dramatically. For example, the rapid growth of bandwidth-hungry applications such as video streaming and multimedia file sharing is pushing the limits of current cellular systems. One solution to addressing the increased demand for bandwidth is to rely on the capability of direct UE-to-UE communication (which may also be referred to as device-to-device (D2D) or sidelink communication), which allows two nearby devices (e.g., UEs) to communicate with each other within the cellular bandwidth without or with limited base station involvement. However, the introduction of D2D poses many new challenges to the long-standing cellular architecture, which revolves around a base station that manages an array of mobile devices within its coverage area.

[0018] For example, typically in an access link scenario (e.g., communication management by a base station), a UE requesting transmission of uplink traffic may first send a scheduling request (SR) to the base station, which indicates that the UE has uplink data to send, so that the base station can schedule the UE using an uplink grant. Conversely, if the base station has downlink data to send to the UE, the base station may schedule the UE on the downlink. In addition, in the event that the UE requests to receive data (e.g., downlink traffic) from the base station or the network, the UE may again send appropriate upper layer signaling, which results in the generation of downlink data at the base station that is scheduled by the base station on the downlink. In each instance, initial access begins with a random access procedure or connection establishment, and only the SR itself is required to initiate the presence of uplink data.

[0019] In the Long Term Evolution (LTE) architecture, a UE may typically transmit on sidelink resources in a transmitter resource pool without any SR being sent by either UE. In such instances, the nature of the transmission may depend on the resource pool configuration (e.g., Mode-1, Mode-2 scheduling, etc.). However, no scheduling request signal is required to initiate a sidelink communication. Instead, a UE may have pre-configured transmit and receive pools, or may attempt to obtain a Sidelink Synchronization Signal (SLSS) and pool configuration information from other sidelink UEs for synchronization in time and frequency. However, even so, all subsequent sidelink communications do not require any SR transmission to schedule sidelink transmission or reception.

[0020] Built on the LTE architecture, one aspect of 5G NR communication technology includes the use of high-frequency spectrum bands, such as above 24 GHz, which may be referred to as millimeter wave (mmW) bands. The use of these bands enables extremely high data rates and a significant increase in data processing capabilities. However, compared to LTE, mmW bands are susceptible to rapid channel variations and suffer from severe free space path loss and atmospheric absorption. In addition, mmW bands are extremely susceptible to obstruction (e.g., hands, head, body, foliage, building penetration). In particular, at mmW frequencies, even small changes in the environment, such as turning of the head, movement of the hand, or a passing car, may change the channel conditions between the base station and the user device and therefore affect communication performance.

[0021] Current mmW 5G NR systems utilize the small wavelengths of mmW at higher frequencies to utilize multiple-input, multiple-output (MIMO) antenna arrays to create highly directional beams that focus the transmitted radio frequency (RF) energy in an attempt to overcome propagation and path loss challenges in both the uplink and downlink. Therefore, unlike LTE, direct transmissions such as D2D or sidelink communications between multiple UEs require some initial access procedures to establish beam pairing, even within the coverage area of a base station. However, there is currently no beam pairing process or technology that facilitates the establishment of sidelink communications in 5G NR systems.

[0022] Aspects of the present disclosure address the aforementioned issues by providing techniques for configuring D2D communications for one or more user equipments (UEs) in NR. Specifically, features of the present disclosure provide techniques for initial beam pairing for sidelink communications that optimize communication resources (e.g., resource pools) by indicating the direction of traffic (e.g., transmit or receive, or both) during the initial beam pairing process and establishing sidelink communications without requiring SR transmission.

[0023] To this end, the initial beam pairing techniques disclosed herein for sidelink communications in a 5G NR system may include transmitting a random access signal (e.g., a physical random access channel (PRACH)) from a first UE to a second UE on resources corresponding to a beam synchronization control signal (e.g., a synchronization signal block (SSB)). In some aspects, the random access signal may be transmitted on resources corresponding to beams from a plurality of SSB beams that may be identified by the UE as supporting a high received signal-to-noise ratio (SNR) (e.g., if the signal quality on a particular beam exceeds a predetermined threshold). Once beam pairing is established, the two UEs may transmit directly to each other using the identified beam(s) (assuming there is appropriate overlap between transmit (Tx) and receiver (Rx) resource pools).

[0024] In addition, to optimize resource pool management, the random access signal may additionally indicate the direction of the traffic requested by the UE, which identifies whether the UE initiating the sidelink communication (e.g., the first UE) is requesting only transmission of data, only reception from the second UE, or both transmission and reception from the second UE. In some examples, the direction of the traffic may be indicated using the partitioning of the PRACH sequence space and / or resource space. In some instances, details of the nature of the Rx data (e.g., upper layer traffic type, etc.) may also be indicated in a subsequent initial access message or through further PRACH partitioning.

[0025] Thus, in an instance where the first UE intends to receive data only from the second UE, the indication of the direction of the traffic in the random access signal during the initial beam pairing sequence can allow the second UE to forgo monitoring the Rx resource pool used for transmissions from the first UE. In other words, understanding that the first UE only intends to receive data from the second UE, the second UE can determine that the first UE does not intend to send any data to the second UE. Thus, the second UE can save resources by choosing not to monitor the resources corresponding to the Rx resource pool corresponding to the second UE. This can help the second UE reuse these resources to send or receive other communications that may have a higher priority with (multiple) other UEs and / or (multiple) base stations, and / or reduce the power consumption of the second UE by reducing resource monitoring.

[0026] Similarly, in instances where the first UE intends to transmit only data to the second UE, the indication of the direction of traffic in the random access signal may allow the first UE to not activate its Rx resource pool, since the second UE will know not to transmit to the first UE. However, if the indication of the direction of traffic identifies that the first UE requests both transmission and reception of data, both the Tx and Rx resource pools may be activated for both the first UE and the second UE.

[0027] For non-reciprocal cases (or cases where there are no Tx-Rx beam corresponding UEs) (e.g., where a first UE determines a receive beam to receive and identify a suitable SSB, but then cannot form a transmit beam having a beam shape close enough to the receive beam shape, or similarly, a second UE cannot form a receive beam having a shape close enough to the transmit beam it uses to transmit the SSB), features of the present disclosure further provide for beam scanning a random access signal (with a direction indicated by the traffic) across multiple beams so that the second UE can detect the random access signal at an Rx beam suitable for the second UE. In some instances, the first UE may repeat the transmission of the random access signal across each of the multiple Tx beams to allow the second UE an opportunity to optimize the second UE's Rx beam and establish communication on the identified beam for subsequent transmissions from the first UE. However, in some instances, if the first UE only intends to receive data from the second UE, then repeated transmission of the random access signal across multiple beams may not be necessary, and therefore any subsequent transmissions may not be required. In some instances, even if the first UE only intends to receive data from the second UE, these repeated transmissions may be needed if the received data must be acknowledged, for example by a HARQ feedback indication, in which case the repetitions improve the reliability of such acknowledgement feedback.

[0028] Now Figure 1-Figure 4 Various aspects are described in more detail. In the following description, for the purpose of explanation, many specific details are set forth in order to provide a thorough understanding of one or more aspects. However, it is apparent that such (multiple) aspects can be practiced without these specific details. In addition, the term "component" used herein can be one of the parts that constitute a system, which can be hardware, firmware and / or software stored on a computer-readable medium, and can be split into other components.

[0029] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of this disclosure. Various examples may omit, replace, or add various processes or components as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined in other examples.

[0030] Figure 1is a diagram illustrating an example of a wireless communication system and access network 100 for sidelink communication according to aspects of the present disclosure. Specifically, the wireless communication system 100 may include one or more base stations 102, one or more UEs 104, and a core network such as an evolved packet core (EPC) 180 and / or a 5G core (5GC) 190. One or more base stations 102 and / or UEs 104 may operate according to millimeter wave (mmW or mmWave) technology. For example, mmW technology includes transmissions at mmW frequencies and / or near-mmW frequencies. Specifically, extremely high frequency (EHF) is a portion of the radio frequency (RF) in the electromagnetic spectrum, where EHF ranges from 30 GHz to 300 GHz and has a wavelength between 1 mm and 10 mm. Radio waves in this frequency band may be referred to as millimeter waves. Near-millimeter waves may extend down to a frequency of 3 GHz and have a wavelength of 100 mm. For example, the super high frequency (SHF) band extends between 3 GHz and 30 GHz and may also be referred to as centimeter waves.

[0031] As described above, communications using mmW and / or near-mmW radio frequency bands have extremely high path loss and short range. Therefore, the propagation characteristics of the mmW environment require the deployment of dense gNBs 102 (i.e., base stations 102 in NR technology) to ensure line-of-sight optical links at any given time and reduce the probability of outages. Certain UEs 104 may also communicate with each other using device-to-device (D2D) communication links 138. The D2D communication links 138 may use DL / UL WWAN spectrum. The D2D communication links 138 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communications may be carried out over various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE802.11 standard, LTE, or NR. To this end, the UE 104 may include a sidelink communication management component 350 (see Figure 3 ) to implement techniques for configuring D2D communications for one or more UEs in NR. Specifically, the sidelink communication management component 350 can optimize communication resources (e.g., resource pools) by indicating the direction of traffic (e.g., transmit or receive) during the initial beam pairing process and establishing sidelink communications without the need for SR transmission.

[0032] The EPC 180 and / or 5GC 190 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The base station 102 may perform one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC 180 or 5GC 190) via backhaul links 132, 134 (e.g., Xn, X1, or X2 interfaces), which may be wired or wireless communication links.

[0033] Base stations 102 can communicate wirelessly with UEs 104 via one or more base station antennas. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. In some examples, base stations 102 can be referred to as base transceiver stations, radio base stations, access points, access nodes, radio transceivers, NodeBs, eNodeBs (eNBs), gNBs, Home NodeBs, Home eNodeBs, gNodeBs (gNBs), relays, transceiver functions, basic service sets (BSSs), extended service sets (ESSs), transmit receive points (TRPs), or other suitable terminology. The geographic coverage area 110 of a base station 102 can be divided into sectors or cells that constitute only a portion of the coverage area (not shown). The wireless communication network 100 can include different types of base stations 102 (e.g., macro base stations 102 or small cell base stations 180, as described below).

[0034] In some examples, the wireless communication network 100 can be or include one or any combination of communication technologies, including NR or 5G technology, long term evolution (LTE) or advanced LTE (LTE-A) or MultiLTEfire technology, Wi-Fi technology, Bluetooth technology, or any other long-range or short-range wireless communication technology. The wireless communication network 100 can be a heterogeneous technology network in which different types of base stations provide coverage for various geographic areas. For example, each base station 102 can provide communication coverage for a macro cell, a small cell, or other type of cell. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area of a carrier or base station (e.g., a sector, etc.), depending on the context.

[0035] A macro cell may typically cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs 104 with a service subscription from a network provider. Compared to a macro cell, a small cell may include a base station with relatively low transmit power that may operate in the same or different frequency bands (e.g., licensed, unlicensed, etc.) as the macro cell. According to various examples, a small cell may include a pico cell, a femto cell, and a micro cell. For example, a pico cell may cover a small geographic area and may allow unrestricted access to UEs 104 with a service subscription from a network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access and / or unrestricted access to UEs 104 associated with the femto cell (e.g., in the case of restricted access, the UE 104 is in a closed subscriber group (CSG) of the base station 102, which may include UEs 104 for home users, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or more (eg, two, three, four, etc.) cells (eg, component carriers).

[0036] The communication network that can adapt to some of the various disclosed examples can be a packet-based network that operates according to a layered protocol stack and the data in the user plane can be based on IP. The user plane protocol stack (e.g., Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), MAC, etc.) can perform packet segmentation and reassembly to communicate through logical channels. For example, the MAC layer can perform priority processing and multiplex logical channels into transport channels. The MAC layer can also use hybrid automatic repeat / request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the RRC protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the UE 110 and the base station 105. The RRC protocol layer can also be used for the core network 115 to provide support for radio bearers for user plane data. At the physical (PHY) layer, transport channels can be mapped to physical channels.

[0037] UEs 104 may be distributed throughout the wireless communication network 100, and each UE 104 may be fixed or mobile. UEs 104 may also include or be referred to by those skilled in the art as mobile stations, subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, handsets, user agents, mobile clients, clients, or some other suitable terminology. UEs 104 may be cellular phones, smartphones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, tablet computers, laptop computers, cordless phones, smart watches, wireless local loop (WLL) stations, entertainment devices, vehicle-mounted components, business premises equipment (CPE), or any device capable of communicating in the wireless communication network 100. Some non-limiting examples of UE 104 include a Session Initiation Protocol (SIP) phone, a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Additionally, UE 104 may be an Internet of Things (IoT) and / or Machine-to-Machine (M2M) type device, e.g., a low-power, low-data-rate type device (e.g., relative to a wireless phone) that, in some aspects, may not frequently communicate with the wireless communication network 100 or other UEs. UE 104 may be capable of communicating with various types of base stations 102 and network devices including macro eNBs, small cell eNBs, macro gNBs, small cell gNBs, gNBs, relay base stations, and the like.

[0038] UE 104 can be configured to establish one or more wireless communication links 120 with one or more base stations 102. The wireless communication links 120 shown in wireless communication network 100 can carry uplink (UL) transmissions from UE 104 to base station 102 or downlink (DL) transmissions from base station 102 to UE 104. Each wireless communication link 120 can include one or more carriers, where each carrier can be a signal composed of multiple subcarriers (e.g., waveform signals of different frequencies) modulated according to the various radio technologies described above. Each modulated signal can be transmitted on a different subcarrier and can carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. In one aspect, wireless communication link 120 can use frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources) to transmit bidirectional communications. Frame structures can be defined for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2). Furthermore, in some aspects, wireless communication link 120 can represent one or more broadcast channels.

[0039] In some aspects of the wireless communication network 100, the base station 102 or the UE 104 may include multiple antennas to employ an antenna diversity scheme to improve the communication quality and reliability between the base station 102 and the UE 104. Additionally or alternatively, the base station 102 or the UE 104 may employ multiple-input multiple-output (MIMO) technology, which can take advantage of a multipath environment to transmit multiple spatial layers carrying the same or different coded data.

[0040] The wireless communication network 100 may also support operation on multiple cells or carriers, a feature that may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), layer, channel, etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably herein. The UE 104 may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation. Carrier aggregation may be used with both FDD and TDD component carriers. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The base station 105 and / or the UE 110 may use spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 30, 50, 100, 200, 400 MHz, etc.) per carrier allocated in carrier aggregation for transmission in each direction totaling up to Yx MHz (x = number of component carriers). The carriers may or may not be adjacent to each other. The allocation of carriers can be asymmetric for DL and UL (e.g., more or fewer carriers can be allocated for DL than for UL). A component carrier can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as a primary cell (PCell) and the secondary component carrier can be referred to as a secondary cell (SCell).

[0041] The wireless communication network 100 may also include a base station 102 operating in accordance with Wi-Fi technology, e.g., a Wi-Fi access point communicating with a UE 110 operating in accordance with Wi-Fi technology, e.g., a Wi-Fi station (STA) via a communication link in an unlicensed spectrum (e.g., 5 GHz). When communicating in an unlicensed spectrum, the STA and the AP may perform a clear channel assessment (CCA) or a listen-before-talk (LBT) procedure prior to communication to determine whether a channel is available.

[0042] Small cells can operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cells can employ NR and use the same 5 GHz unlicensed spectrum used by Wi-Fi APs. Small cells employing NR in unlicensed spectrum can improve access network coverage and / or increase access network capacity.

[0043] In a non-limiting example, EPC 180 may include a Mobility Management Entity (MME) 181, other MMEs 182, a Serving Gateway 183, a Multimedia Broadcast Multicast Service (MBMS) Gateway 184, a Broadcast Multicast Service Center (BM-SC) 185, and a Packet Data Network (PDN) Gateway 186. MME 181 may communicate with a Home Subscriber Server (HSS) 187. MME 181 is a control node that handles signaling between UE 110 and EPC 180. Typically, MME 181 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through Serving Gateway 183, which itself is connected to PDN Gateway 186. PDN Gateway 186 provides UE IP address allocation and other functions. PDN Gateway 186 and BM-SC 185 are connected to IP Services 188. IP Services 188 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 185 can provide functionality for MBMS user service provisioning and delivery. The BM-SC 185 can serve as the entry point for content providers' MBMS transmissions, can be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and can be used to schedule MBMS transmissions. The MBMS Gateway 184 can be used to distribute MBMS services to base stations 105 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area that broadcasts specific services, and can be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0044] 5GC 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. AMF 192 may communicate with a unified data management (UDM) 196. AMF 192 is a control node that handles signaling between UE 110 and 5GC 190. Typically, AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 is connected to IP services 197. IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0045] Figure 2 A diagram 220 is shown illustrating support for beam pairing for sidelink communication according to aspects of the present disclosure. Specifically, beamforming is a technique for directional signal transmission and reception. Diagram 220 shows an example of beamforming operation and may include a first UE 104-a and a second UE 104-b.

[0046] As mentioned above, one aspect of 5G NR communication technology includes the use of high-frequency spectrum bands (such as above 24 GHz, which may be referred to as mmW bands). While the use of these bands can achieve extremely high data rates and significantly improve data processing capabilities, mmW bands are susceptible to rapid channel variations and suffer from severe free space path loss and atmospheric absorption. In addition, mmW bands are extremely susceptible to obstruction (e.g., penetration by hands, heads, bodies, leaves, buildings). Especially at mmW frequencies, even small changes in the environment, such as turning the head, moving the hand, or a passing car, may change the channel conditions between the base station and the user device and, therefore, affect communication performance.

[0047] To address this issue, mmW 5G NR systems can utilize the small wavelengths of mmW at higher frequencies to utilize MIMO antenna arrays to create highly directional beams that focus the transmitted RF energy in an attempt to overcome the propagation and path loss challenges for both uplink and downlink. To this end, the beamforming arrays of one or more UEs 104 may include one or more antennas 365 (see FIG. 1 ) for employing MIMO technology. Figure 3 ), which can take advantage of the multipath environment to transmit multiple spatial layers carrying the same or different coded data. Because D2D communication does not require SR transmission before direct communication between multiple UEs 104, and 5G NR requires some initial access procedures to establish beam pairing, aspects of the present disclosure provide techniques for configuring D2D communication for one or more UEs 104 in NR. Specifically, features of the present disclosure provide techniques for initial beam pairing (e.g., selecting a beam (e.g., beam 225-b) from multiple beams 225) for sidelink communication, which optimizes communication resources (e.g., resource pool) by indicating the direction of the traffic (e.g., transmission or reception) during the initial beam pairing process and establishing sidelink communication without the need for SR transmission.

[0048] Beamforming at the transmitter can involve phase shifting the signals generated at different antennas 365 in the array to focus the transmission in a specific direction. The phase-shifted signals can interact to produce constructive interference in some directions and destructive interference in other directions. By focusing signal power, the transmitter can increase communication throughput while reducing interference with neighboring transmitters.

[0049] Similarly, beamforming at the receiver can involve phase shifting the signals received from different antennas 365. When the phase-shifted signals are combined, the receiver can amplify signals from certain directions and reduce signals from other directions. In some cases, the receiver and transmitter can utilize beamforming techniques independently of each other. In other cases, the transmitter and receiver can coordinate to select the beam direction. The use of beamforming can depend on factors such as the type of signal being transmitted and the channel conditions. For example, directional transmission may not be useful when transmitting to multiple receivers, or when the locations of the receivers are unknown. Thus, beamforming may be suitable for unicast transmissions, but may not be suitable for broadcast transmissions. In addition, beamforming may be appropriate when transmitting in high-frequency radio bands such as mmW bands.

[0050] Because the beamforming array size is proportional to the signal wavelength, smaller devices (e.g., UEs) may also be able to perform beamforming in high-frequency bands. In addition, the increased received power can compensate for the increased path loss at these frequencies. In some examples, the beamforming pattern 220 may include one or more beams 225, which can be identified by individual beam IDs (e.g., a first beam 225-a, a second beam 225-b, a third beam 225-c, etc.).

[0051] Typically, in a system such as a 5G NR mmW system, a transmitter (e.g., a first UE 104-a) can transmit multiple directional candidate beams 225 (e.g., 225-a, 225-b, 225-c, etc.) to a desired second UE 104-b for communication. In turn, the second UE 104-b can measure the reference signal received power (RSRP) of each candidate beam 225 to identify one or more beams that maximize the receiver signal-to-noise ratio (SNR). Based on the RSRP measurement values, the UE 104 can select one or more beams (e.g., the first beam 225-a) from the multiple candidate beams 325 for communication.

[0052] According to aspects of the present disclosure, an initial beam pairing technique for sidelink communications in a 5G NR system of the present disclosure may include transmitting a random access signal 230 (e.g., a physical random access channel (PRACH)) from a first UE to a second UE on resources corresponding to a beam synchronization control signal (e.g., a synchronization signal block (SSB)). In some aspects, the random access signal 230 may be transmitted on a beam 225-b from a plurality of beams 225 that may be identified by the UE 104 as supporting a high SNR (e.g., if the signal quality on a particular beam (e.g., the second beam 228-b) exceeds a predetermined threshold). Once beam pairing is established, both UEs may transmit directly to each other 235 using the identified beam(s) (provided there is appropriate overlap between the Tx and Rx resource pools).

[0053] Furthermore, to optimize resource pool management, the random access signal 230 may additionally indicate the direction of traffic requested by the UE 104, identifying whether the UE initiating the sidelink communication (e.g., the first UE 104-a) is requesting only transmission of data, reception only from the second UE 104-b, or both transmission and reception from the second UE 104-b. In some examples, the direction of traffic may be indicated using a partitioning of the PRACH sequence space and / or resource space. In some instances, details of the nature of the Rx data (e.g., upper layer traffic type, etc.) may also be indicated in a subsequent initial access message or through further PRACH partitioning.

[0054] Thus, in one instance where the first UE 104-a intends to receive data only from the second UE 104-b, the indication of the direction of the traffic in the random access signal 230 during the initial beam pairing sequence may allow the second UE 104-b to forgo monitoring the Rx resource pool for transmissions from the first UE 104-a. Thus, the second UE 104-b may conserve resources by electing not to monitor the resources corresponding to the Rx resource pool corresponding to the second UE 104-b.

[0055] Similarly, in the event that the first UE 104-a intends to transmit data only to the second UE 104-b, the direction of traffic indication in the random access signal 230 may allow the first UE 104-a to not activate its Rx resource pool since the second UE 104-b will know not to transmit to the first UE 104-a. However, if the direction of traffic indication identifies that the first UE 104-a requests both transmission and reception of data, both the Tx and Rx resource pools may be activated for both the first UE 104-a and the second UE 104-b.

[0056] For non-reciprocal cases (or cases where there are no Tx-Rx beam corresponding (multiple) UEs) (e.g., where the first UE 104-a determines a receive beam to receive and identify a suitable SSB, but then cannot form a transmit beam having a beam shape close enough to the receive beam shape, or similarly, the second UE 104-b cannot form a receive beam having a shape close enough to the transmit beam it used to transmit the SSB), features of the present disclosure further provide for beam scanning a random access signal 230 (with an indication of the direction of the traffic) across multiple beams 225 so that the second UE 104-b can detect the random access signal 230 at an Rx beam appropriate for the second UE 104-b. In some instances, the first UE 104-a may repeat the transmission of the random access signal 230 on each of the multiple Tx beams to allow the second UE 104-b an opportunity to optimize the Rx beam of the second UE 104-b and establish communication 235 on the identified beam for subsequent transmissions from the first UE 104-a. However, in some instances, if the first UE 104-a only intends to receive data from the second UE 104-b, then repeated transmissions of the random access signal 230 on the multiple beams 225 may not be necessary, and therefore any subsequent transmissions will not be required. In some instances, even if the first UE 104-a only intends to receive data from the second UE 104-b, these repeated transmissions may be required if the received data must be acknowledged, for example, by a HARQ feedback indication, in which case the repetitions improve the reliability of such acknowledgment feedback.

[0057] It should be noted that although the above description refers to SSBs and associated PRACH resources, the waveform of an "SSB" transmission is not necessarily similar to the SSB used by the gNB for access link or sidelink SSBs, and similarly, the waveform of a "PRACH" transmission is not necessarily similar to the access link PRACH. An SSB in the context of this invention refers to any sidelink transmit beam used for initial beam pairing purposes. Similarly, a PRACH refers to any signal whose resources are associated with a corresponding SSB to facilitate beam pairing. PRACH resources can be contention-based, contention-free, or a combination of both. Information can be included in a PRACH transmission via partitioning of the PRACH resources (i.e., the selected PRACH resource indicates the information to be included) or via a payload message carried in the PRACH (e.g., in the case of "2-step RACH" operation, where the PRACH includes both sequence and payload transmissions).

[0058] Figure 3The diagram illustrates hardware components and subcomponents of a device that may be a UE 104 for implementing one or more methods described herein, such as method 400, according to various aspects of the present disclosure. For example, one example of an implementation of the UE 104 may include various components, some of which have been described above, but including components such as one or more processors 312, memory 316, and transceiver 302 communicating via one or more buses 344, which may operate in conjunction with a communication management component 350 to perform the functionality described herein in connection with one or more methods, such as 400, including the present disclosure.

[0059] The one or more processors 312, modem 314, memory 316, transceiver 302, RF front end 388, and one or more antennas 365 can be configured to support voice and / or data calls (simultaneously or non-simultaneously) in one or more wireless point access technologies. In one aspect, the one or more processors 312 can include a modem 314 that utilizes one or more modem processors. Various functions associated with the communication management component 350 can be included in the modem 314 and / or processor 312, and in one aspect, can be performed by a single processor, while in other aspects, different functions can be performed by a combination of two or more different processors. For example, in one aspect, the one or more processors 312 can include a modem processor, a baseband processor, a digital signal processor, a transmit processor, a receiver processor, or any one or any combination of transceiver processors associated with the transceiver 302. In other aspects, some features of the one or more processors 312 and / or modem 314 associated with the communication management component 350 can be performed by the transceiver 302.

[0060] The memory 316 can be configured to store data used herein and / or application(s) 375 or a local version of the communication management component 350 and / or one or more subcomponents thereof executed by the at least one processor 312. The memory 316 can include any type of computer-readable medium usable by a computer or the at least one processor 312, such as random access memory (RAM), read-only memory (ROM), tape, magnetic disk, optical disk, volatile memory, non-volatile memory, and any combination thereof. In one aspect, for example, the memory 316 can be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining one or more of the communication management component 350 and / or its subcomponents, and / or data associated therewith, when the UE 104 operates the at least one processor 312 to execute the sidelink communication management component 350 and / or one or more subcomponents thereof. The sidelink communication management component 350 can include a beam pairing component 360 for identifying one or more beams from a plurality of beams to establish sidelink communication with at least one second UE. In some examples, beam pairing component 360 can cooperate with RACH component 365 to transmit a random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal. As described above, in some instances, the random access signal can include information related to the direction of the traffic.

[0061] The transceiver 302 may include at least one receiver 306 and at least one transmitter 308. The receiver 306 may include hardware, firmware, and / or software code executable by a processor for receiving data, the code including instructions and stored in a memory (e.g., a computer-readable medium). The receiver 306 may be, for example, a radio frequency (RF) receiver. In one aspect, the receiver 306 may receive signals transmitted by at least one UE 104. In addition, the receiver 306 may process such received signals and may also obtain signal measurements such as, but not limited to, Ec / Io, SNR, RSRP, RSSI, etc. The transmitter 308 may include hardware, firmware, and / or software code executable by a processor for transmitting data, the code including instructions and stored in a memory (e.g., a computer-readable medium). Suitable examples of the transmitter 308 may include, but are not limited to, an RF transmitter.

[0062] Furthermore, in one aspect, the transmitting device may include an RF front end 388 that may be operable to communicate with the one or more antennas 365 and the transceiver 302 to receive and transmit radio transmissions, such as wireless transmissions transmitted by at least one base station 102 or wireless transmissions transmitted by the UE 104. The RF front end 388 may be connected to the one or more antennas 365 and may include one or more low noise amplifiers (LNAs) 390, one or more switches 392, one or more power amplifiers (PAs) 398, and one or more filters 396 for transmitting and receiving RF signals.

[0063] In one aspect, the LNAs 390 can amplify received signals at a desired output level. In one aspect, each LNA 390 can have specified minimum and maximum gain values. In one aspect, the RF front end 388 can use one or more switches 392 to select a particular LNA 390 and its specified gain value based on the desired gain value for a particular application.

[0064] Furthermore, for example, the RF front end 388 can use one or more PAs 398 to amplify the signal for RF output at a desired output power level. In one aspect, each PA 398 can have a specified minimum and maximum gain value. In one aspect, the RF front end 388 can use one or more switches 392 to select a particular PA 398 and its specified gain value based on the desired gain value for a particular application.

[0065] In addition, for example, the RF front end 388 can use one or more filters 396 to filter the received signal to obtain an input RF signal. Similarly, in one aspect, for example, a corresponding filter 396 can be used to filter the output from the corresponding PA 398 to produce an output signal for transmission. In one aspect, each filter 396 can be connected to a designated LNA 390 and / or PA 398. In one aspect, the RF front end 388 can use one or more switches 392 to select a transmit or receive path using a designated filter 396, LNA 390, and / or PA 398 based on a configuration specified by the transceiver 302 and / or the processor 312.

[0066] As such, the transceiver 302 can be configured to transmit and receive wireless signals via the RF front end 388 through one or more antennas 365. In one aspect, the transceiver 302 can be tuned to operate at a specified frequency so that the transmitting device can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102. In one aspect, the modem 314 can configure the transceiver 302 to operate at a specified frequency and power level, for example, based on the configuration of the transmitting device and the communication protocol used by the modem 314.

[0067] In one aspect, the modem 314 can be a multi-band multi-mode modem that can process digital data and communicate with the transceiver 302 so that digital data is sent and received using the transceiver 302. In one aspect, the modem 314 can be multi-band and can be configured to support multiple frequency bands of a specified communication protocol. In one aspect, the modem 314 can be multi-mode and configured to support multiple operating networks and communication protocols. In one aspect, the modem 314 can control one or more components of the transmitting device (e.g., RF front end 388, transceiver 302) to enable transmission and / or reception of signals from the network based on a specified modem configuration. In one aspect, the modem configuration can be based on the mode of the modem 314 and the frequency band used. In another aspect, the modem configuration can be based on UE configuration information associated with the transmitting device provided by the network during cell selection and / or cell reselection.

[0068] refer to Figure 4 , an example method 400 for wireless communication according to aspects of the present disclosure may be provided by reference to Figure 1 and Figure 2 The discussed one or more UEs 104 perform. Although the method 400 is described below with respect to elements of a UE 104, other components may be used to implement one or more of the steps described herein.

[0069] At block 405, method 400 may include initiating an initial beam pairing procedure at the first UE to establish sidelink communication with the second UE. Figure 3 As described, aspects of block 405 can be performed by sidelink communication management component 350, and more specifically, can be performed by beam pairing component 360. Thus, sidelink communication management component 350, beam pairing component 360, modem 314, processor 312, and / or UE 104, or one of its subcomponents, can define means for initiating an initial beam pairing procedure at a first UE to establish sidelink communication with a second UE.

[0070] At block 410, method 400 may include determining whether the first UE is scheduled to transmit data, receive data from the second UE, or both. Figure 3 As described, aspects of block 410 may also be performed by sidelink communication management component 350, and more specifically, by RACH component 365. Thus, sidelink communication management component 350, RACH component 365, modem 314, processor 312, and / or UE 104, or one of its subcomponents, may define means for determining whether a first UE is scheduled to transmit data, receive data from a second UE, or both.

[0071] At block 415, method 400 may include identifying the direction of the traffic based on determining whether the first UE is scheduled to transmit data or receive data from the second UE, or both transmit data or receive data from the second UE. In some examples, identifying the direction of the traffic may include determining that the first UE requests to receive data from the second UE, and identifying the direction of the traffic as a transmission from the second UE to the first UE, wherein the direction indication of the traffic from the second UE to the first UE allows the second UE to omit monitoring of a receiver resource pool for any transmission from the second UE. In other examples, identifying the direction of the traffic may include determining that the first UE requests to transmit data to the second UE, and identifying the direction of the traffic as a transmission from the first UE to the second UE, wherein the direction indication of the traffic from the first UE to the second UE allows the first UE to omit monitoring of a receiver resource pool for any transmission from the second UE. In yet another example, identifying the direction of the traffic may include determining that the first UE requests both transmission and reception of data, and identifying the direction of the traffic as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission traffic indication configures the first UE to activate both the transmitter and receiver resource pools. As shown in reference Figure 3 As described, aspects of block 415 can be performed by sidelink communication management component 350, and more specifically, by RACH component 365. Thus, sidelink communication management component 350, RACH component 365, modem 314, processor 312, and / or UE 104, or one of its subcomponents, can define means for identifying the direction of traffic based on determining whether the first UE is scheduled to transmit data, receive data from the second UE, or both transmit data or receive data from the second UE.

[0072] At block 420, the method may include sending a random access signal from the first UE to the second UE on a resource corresponding to the beam synchronization control signal, wherein the random access signal includes information associated with the direction of the traffic. In some examples, sending the random access signal may include identifying a beam from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam. In other examples, sending the random access signal may include sending the random access signal on a plurality of beams to allow the second UE to identify a beam from a plurality of beams to establish sidelink communication between the first UE and the second UE. As described in reference Figure 3 As described, aspects of block 420 may be performed by transceiver 302, sidelink communication management component 350, and RACH component 365. Thus, transceiver 302, sidelink communication management component 350, RACH component 365, modem 314, processor 312, and / or UE 104, or one of its subcomponents, may define means for transmitting a random access signal from a first UE to a second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with a direction of the traffic.

[0073] Some more examples

[0074] An example method for wireless communication includes: at a first user equipment (UE), initiating an initial beam pairing process to establish sidelink communication with a second UE; determining whether the first UE is scheduled to send data or receive data from the second UE, or both; identifying a direction of traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both; and sending a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of traffic.

[0075] According to the above example method, wherein sending the random access signal may include identifying a beam from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

[0076] According to any of the above example methods, wherein sending the random access signal may include sending the random access signal on multiple beams to allow the second UE to identify a beam from the multiple beams to establish sidelink communication between the first UE and the second UE.

[0077] According to any of the above-mentioned example methods, wherein the direction of the traffic is identified based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE, including: determining that the first UE requests to receive data from the second UE; and identifying the direction of the traffic as a transmission from the second UE to the first UE, wherein the direction indication of the traffic from the second UE to the first UE allows the second UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0078] According to any of the above-mentioned example methods, wherein the direction of the traffic is identified based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE, including: determining that the first UE requests the transmission of data to the second UE; and identifying the direction of the traffic as a transmission from the first UE to the second UE, wherein the direction indication of the traffic from the first UE to the second UE allows the first UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0079] According to any one of the above-mentioned example methods, wherein the direction of the service is identified based on determining whether the first UE is scheduled to send or receive data from the second UE or both send data or receive data from the second UE, including: determining that the first UE requests both sending and receiving data; identifying the direction of the service as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission service indication configures the first UE to activate both the transmitter and receiver resource pools.

[0080] An example apparatus for wireless communication comprises: a memory configured to store instructions; a processor communicatively coupled to the memory, the processor configured to execute the instructions to: at a first user equipment (UE), initiate an initial beam pairing process to establish sidelink communication with a second UE; determine whether the first UE is scheduled to send data or receive data from the second UE, or both; identify a direction of traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both; and send a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of traffic.

[0081] According to the above-mentioned example apparatus, the instructions for sending a random access signal may include instructions executed by a processor to identify a beam from a plurality of directional beams to establish sidelink communication between a first UE and a second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

[0082] According to any of the above-mentioned example apparatuses, wherein the instructions for sending a random access signal may include instructions executed by a processor to send the random access signal on multiple beams to allow the second UE to identify a beam from the multiple beams to establish sidelink communication between the first UE and the second UE.

[0083] According to any one of the above-mentioned example devices, the instructions for identifying the direction of the service based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE may also include instructions for the processor to execute the following: determine that the first UE requests to receive data from the second UE; identify the direction of the service as a transmission from the second UE to the first UE, wherein the direction indication of the service from the second UE to the first UE allows the second UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0084] According to any one of the above-mentioned example devices, the instructions for identifying the direction of the service based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE may also include instructions for the processor to execute the following: determine that the first UE requests the transmission of data to the second UE; identify the direction of the service as a transmission from the first UE to the second UE, wherein the direction indication of the service from the first UE to the second UE allows the first UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0085] According to any one of the above-mentioned example devices, the instructions for identifying the direction of the service based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE may also include instructions executed by the processor to: determine that the first UE requests both sending and receiving data; identify the direction of the service as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission service indication configures the first UE to activate both the transmitter and receiver resource pools.

[0086] An example non-transitory computer-readable medium storing instructions executable by a processor for wireless communication includes instructions for: at a first user equipment (UE), initiating an initial beam pairing process to establish sidelink communication with a second UE; determining whether the first UE is scheduled to send data or receive data from the second UE, or both; identifying a direction of traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both; and sending a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of traffic.

[0087] According to the above example non-transitory computer-readable medium, wherein sending a random access signal may include identifying a beam from a plurality of directional beams to establish sidelink communication between a first UE and a second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

[0088] According to any of the above-mentioned example non-transitory computer-readable media, wherein sending the random access signal may include sending the random access signal on multiple beams to allow the second UE to identify the beam from the multiple beams to establish sidelink communication between the first UE and the second UE.

[0089] According to any of the above-mentioned example non-transitory computer-readable media, wherein the direction of the traffic is identified based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE, including: determining that the first UE requests to receive data from the second UE; identifying the direction of the traffic as a transmission from the second UE to the first UE, wherein the direction indication of the traffic from the second UE to the first UE allows the second UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0090] According to any of the above-mentioned example non-transitory computer-readable media, wherein the direction of the traffic is identified based on determining whether the first UE is scheduled to send data or receive data from the second UE or both to send data or receive data from the second UE, including: determining that the first UE requests the transmission of data to the second UE; identifying the direction of the traffic as a transmission from the first UE to the second UE, wherein the direction indication of the traffic from the first UE to the second UE allows the first UE to omit monitoring of a receiver resource pool for any transmission from the second UE.

[0091] According to any one of the above-mentioned example non-transitory computer-readable media, wherein the direction of the service is identified based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE, including: determining that the first UE requests both sending and receiving data; identifying the direction of the service as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission service indication configures the first UE to activate both the transmitter and receiver resource pools.

[0092] An example apparatus for wireless communication includes: a component for initiating an initial beam pairing process at a first user equipment (UE) to establish sidelink communication with a second UE; a component for determining whether the first UE is scheduled to send data or receive data from the second UE, or both; a component for identifying a direction of traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both; and a component for sending a random access signal from the first UE to the second UE on resources corresponding to a beam synchronization control signal, wherein the random access signal includes information associated with the direction of traffic.

[0093] According to the above-mentioned example apparatus, the component for sending a random access signal may include a component for identifying a beam from a plurality of directional beams to establish sidelink communication between a first UE and a second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

[0094] According to any of the above-mentioned example apparatuses, the component for sending the random access signal may include a component for sending the random access signal on multiple beams to allow the second UE to identify the beam from the multiple beams to establish sidelink communication between the first UE and the second UE.

[0095] According to any of the above-mentioned example apparatuses, the component for identifying the direction of the traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both, includes: determining that the first UE requests to receive data from the second UE; and a component for identifying the direction of the traffic as a transmission from the second UE to the first UE, wherein the direction indication of the traffic from the second UE to the first UE allows the second UE to omit monitoring of a receiver resource pool for any transmission from the second UE.

[0096] According to any of the above-mentioned example apparatuses, the component for identifying the direction of the traffic based on determining whether the first UE is scheduled to send data or receive data from the second UE, or both send data or receive data from the second UE, includes: a component for determining that the first UE requests the transmission of data to the second UE; a component for identifying the direction of the traffic as a transmission from the first UE to the second UE, wherein the direction indication of the traffic from the first UE to the second UE allows the first UE to omit monitoring of the receiver resource pool for any transmission from the second UE.

[0097] According to any one of the above-mentioned example devices, the component for identifying the direction of the service based on determining whether the first UE is scheduled to send data or receive data from the second UE or both send data or receive data from the second UE includes: a component for determining that the first UE requests both sending and receiving data; a component for identifying the direction of the service as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission service indication configures the first UE to activate both the transmitter and receiver resource pools.

[0098] The detailed description set forth above in conjunction with the accompanying drawings describes examples and does not represent the only examples that can be implemented or within the scope of the claims. The term "example" as used in this description means "serving as an example, instance, or illustration" and does not mean "preferred" or "superior to other examples." The detailed description includes specific details for the purpose of providing an understanding of the described technology. However, these technologies can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0099] Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

[0100] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed with a specially programmed device, such as, but not limited to, a processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The specially programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The specially programmed processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0101] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, these functions can be stored on or transmitted through a non-transitory computer-readable medium as one or more instructions or codes. Other examples and embodiments are within the scope and spirit of the present disclosure and the appended claims. For example, due to the nature of software, the above functions can be implemented using software executed by a specially programmed processor, hardware, firmware, hard wiring, or any combination of these. The features of the implementation functions can also be physically located in different locations, including being distributed so that some functions are implemented in different physical locations. In addition, as used herein, including in the claims, the "or" used in a list of items starting with "at least one" indicates a disjunctive list, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0102] Computer-readable media include computer storage media and communication media, and communication media include any media that facilitates the transmission of computer programs from one place to another. Storage media can be any available media that can be accessed by a general-purpose or special-purpose computer. As an example and not limitation, computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. In addition, any connection is properly referred to as a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves are used to send software from a website, server or other remote source, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are all included in the definition of medium. As used herein, disks and optical disks include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks and Blu-ray disks, wherein disks usually reproduce data magnetically, while optical disks reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0103] The detailed descriptions set forth above in conjunction with the accompanying drawings are intended as descriptions of various configurations and are not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed descriptions include specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring these concepts.

[0104] Several aspects of the telecommunications system are also presented with reference to various apparatuses and methods. These apparatuses and methods are described in the detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively, "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0105] As an example, an element or any part of an element or any combination of elements can be implemented as a "processing system" including one or more processors. The example of a processor includes a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gating logic, a discrete hardware circuit and other suitable hardware configured to perform the various functions described in the entire disclosure. One or more processors in a processing system can execute software. Software should be broadly interpreted as meaning an instruction, an instruction set, a code, a code segment, a program code, a program, a subroutine, a software component, an application, a software application, a software package, a routine, a subroutine, an object, an executable file, an execution thread, a process, a function, etc., whether referred to as software, firmware, middleware, microcode, hardware description language or other.

[0106] It should be noted that the techniques described herein can be used in various wireless communication networks, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technologies such as CDMA2000 and Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 versions 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA systems may implement technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 902.11 (Wi-Fi), IEEE 902.16 (WiMAX), IEEE 902.20, Flash-OFDM, etc. TMetc. radio technologies. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization called the "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used for the above systems and radio technologies and other systems and radio technologies, including cellular (e.g., LTE) communications on shared radio spectrum bands. However, the following description describes LTE / LTE-A and / or 5G New Radio (NR) systems for example purposes, and the terminology of LTE or 5G NR is used in most of the description below, even though the techniques are applicable to applications outside of LTE / LTE-A and 5G NR, for example, other next generation communication systems.

[0107] The foregoing description of the present disclosure is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the present disclosure. Furthermore, although the elements of the described aspects and / or embodiments may be described or claimed in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. Furthermore, unless otherwise stated, all or part of any aspect and / or embodiment may be used together with all or part of any other aspect and / or embodiment. Therefore, the present disclosure is not limited to the examples and designs described herein, but is to be given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication, comprising: At a first user equipment (UE), initiating an initial beam pairing procedure to establish sidelink communication with a second UE; A random access signal is sent from the first UE to the second UE on resources corresponding to the beam synchronization control signal, wherein the random access signal includes information indicating the direction of the service requested by the first UE, and the information identifies whether the first UE initiating sidelink communication with the second UE is requesting the transmission of data, the reception of data from the second UE, or both the transmission of data and the reception of data from the second UE.

2. The method according to claim 1, wherein Sending the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal includes: A beam is identified from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

3. The method according to claim 1, wherein Sending the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal includes: sending the random access signal to the second UE on multiple beams, The method further comprises: Communication is established between the first UE and the second UE through one or more beams among the plurality of beams used to transmit the random access signal to the second UE.

4. The method according to claim 1, wherein The method further comprises: determining that the first UE requests to receive the data from the second UE; and The direction of the traffic is identified as a transmission from the second UE to the first UE, wherein the indication of the direction of the traffic from the second UE to the first UE allows the second UE to omit monitoring of a receiver resource pool for any transmission from the second UE.

5. The method according to claim 1, wherein The method further comprises: determining that the first UE requests transmission of data to the second UE; Identifying a direction of traffic as transmission from the first UE to the second UE; Based on the direction of the traffic being transmission from the first UE to the second UE, monitoring of the receiver resource pool for any transmission from the second UE is omitted.

6. The method according to claim 1, wherein The method further comprises: determining that the first UE requests both transmission and reception of the data; and The direction of the traffic is identified as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission traffic indication configures the first UE to activate both transmitter and receiver resource pools.

7. An apparatus for wireless communication, comprising: a memory configured to store instructions; a processor communicatively coupled to the memory, the processor configured to execute the instructions to: At a first user equipment (UE), initiating an initial beam pairing procedure to establish sidelink communication with a second UE; and A random access signal is sent from the first UE to the second UE on resources corresponding to the beam synchronization control signal, wherein the random access signal includes information indicating the direction of the service requested by the first UE, and the information identifies whether the first UE initiating sidelink communication with the second UE is requesting the transmission of data, the reception of data from the second UE, or both the transmission of data and the reception of data from the second UE.

8. The device according to claim 7, wherein The instructions to send the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal are further executable to: A beam is identified from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

9. The device according to claim 7, wherein The instructions to send the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal are further executable to: sending the random access signal to the second UE on multiple beams; The instructions may also be executed to: Communication is established between the first UE and the second UE via one or more beams among a plurality of beams used to transmit a random access signal to the second UE.

10. The device according to claim 7, wherein The instructions are further executable to: determining that the first UE requests to receive the data from the second UE; and The direction of the traffic is identified as a transmission from the second UE to the first UE, wherein the indication of the direction of the traffic from the second UE to the first UE allows the second UE to omit monitoring of a receiver resource pool for any transmission from the second UE.

11. The device according to claim 7, wherein The instructions are further executable to: determining that the first UE requests transmission of the data to the second UE; Identifying a direction of traffic as transmission from the first UE to the second UE; as well as Based on the direction of the traffic being transmission from the first UE to the second UE, monitoring of the receiver resource pool for any transmission from the second UE is omitted.

12. The device according to claim 7, wherein The instructions are further executable to: determining that the first UE requests both transmission and reception of the data; and The direction of the traffic is identified as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission traffic indication configures the first UE to activate both transmitter and receiver resource pools.

13. A non-transitory computer-readable medium storing processor-executable instructions for wireless communication, comprising instructions for: At a first user equipment (UE), initiating an initial beam pairing procedure to establish sidelink communication with a second UE; and A random access signal is sent from the first UE to the second UE on resources corresponding to the beam synchronization control signal, wherein the random access signal includes information indicating the direction of the service requested by the first UE, and the information identifies whether the first UE initiating sidelink communication with the second UE is requesting the transmission of data, the reception of data from the second UE, or both the transmission of data and the reception of data from the second UE.

14. The non-transitory computer-readable medium of claim 13, wherein: Sending the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal includes instructions for: A beam is identified from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

15. The non-transitory computer-readable medium of claim 13, wherein: Sending the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal includes instructions for: transmitting the random access signal to the second UE on multiple beams; and The instructions are further executable by the processor to: Communication is established between the first UE and the second UE through one or more beams among the plurality of beams used to transmit the random access signal to the second UE.

16. The non-transitory computer-readable medium of claim 13, wherein: The instructions are further executable to: determining that the first UE requests to receive the data from the second UE; and The direction of the traffic is identified as a transmission from the second UE to the first UE, wherein the indication of the direction of the traffic from the second UE to the first UE allows the second UE to omit monitoring of a receiver resource pool for any transmission from the second UE.

17. The non-transitory computer-readable medium of claim 13, wherein: The instructions are further executable to: determining that the first UE requests transmission of data to the second UE; identifying a direction of traffic as transmission from the first UE to the second UE; and Based on the direction of the traffic being transmission from the first UE to the second UE, monitoring of the receiver resource pool for any transmission from the second UE is omitted.

18. The non-transitory computer-readable medium of claim 13, wherein: The instructions are further executable by the processor to: determining that the first UE requests both transmission and reception of the data; and The direction of the traffic is identified as dual transmission from the first UE to the second UE and from the second UE to the first UE, wherein the dual transmission traffic indication configures the first UE to activate both transmitter and receiver resource pools.

19. An apparatus for wireless communication, comprising: means for initiating an initial beam pairing procedure at a first user equipment (UE) to establish sidelink communication with a second UE; as well as A component for transmitting a random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal, wherein the random access signal includes information indicating the direction of the service requested by the first UE, and the information identifies whether the first UE initiating sidelink communication with the second UE is requesting transmission of data, reception of data from the second UE, or both transmission of data and reception of data from the second UE.

20. The device according to claim 19, wherein The means for transmitting the random access signal from the first UE to the second UE on resources corresponding to the beam synchronization control signal further includes: means for identifying a beam from a plurality of directional beams to establish sidelink communication between the first UE and the second UE, wherein the first UE and the second UE communicate directly with each other using the identified beam.

21. A computer program product comprising instructions which, when executed by a processor, perform the steps of the method according to any one of claims 1 to 6.

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