WO2020197583A1

WO2020197583A1 - System and method for sidelink discovery and communications at high frequencies

Info

Publication number: WO2020197583A1
Application number: PCT/US2019/050006
Authority: WO
Inventors: Majid GHANBARINEJAD; Philippe Sartori
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2019-03-22
Filing date: 2019-09-06
Publication date: 2020-10-01

Abstract

A UE may obtain a resource pool configuration that specifies a plurality of resource pools, and each of the plurality of resource pools is associated with a beamforming direction. The UE may select a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and also in accordance with a communication direction in which a signal is to be communicated by the UE. The UE may then communicate the signal in the communication direction using a first resource of the selected first resource pool.

Description

System and Method for Sidelink Discovery and Communications at

High Frequencies

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional Application No. 62/822,736, filed on March 22, 2019 and entitled“Method and device for communications between user equipments,” which is hereby incorporated by reference herein as if reproduced in its entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication technology, in particular, to a system and method for sidelink discovery and communications at high frequencies. BACKGROUND

To achieve a goal of providing a fifth generationfsG) -compatible high-speed reliable connectivity for vehicular communications in the near future for applications such as safety systems and autonomous driving, the third generation partnership project (3GPP) has approved a study item for the 5G new radio access (NR) technology vehicle-to-eveiything (V2X) wireless communication.

Device-to-device (D2D) mode of communication is a communication mode used in V2X communication. At high frequencies, beamforming is necessary to establish a link between two user equipments (UEs) to compensate for high path loss. The initial beamforming and beam acquisition may be performed blindly during the establishment of the link between the two UEs by using beamforming.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of this disclosure which describe a system and method for sidelink discovery and communications at high frequencies.

According to one aspect of the present disclosure, there is provided a method that includes: obtaining, by a user equipment (UE), a resource pool configuration, with the resource pool configuration specifying a plurality of resource pools, each pool of the plurality of resource pools being associated with a beamforming direction, selecting, by the UE, a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and in accordance with a communication direction, the communication direction being a direction in which a beam is to be formed for communication of the signal, and communicating, by the UE, the signal in the communication direction using a first resource of the first resource pool. An apparatus is provided according to another aspect. The apparatus includes a non-transitoiy memory storage comprising instructions, and one or more processors in communication with the memory storage. The one or more processors execute the instructions to obtain a resource pool configuration, with the resource pool configuration specifying a plurality of resource pools, each pool of the plurality of resource pools being associated with a beamforming direction; select a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and in accordance with a communication direction, the communication direction being a direction in which a beam is to be formed for communication of the signal; and communicate the signal in the communication direction using a first resource of the first resource pool.

The forgoing method and apparatus enable UEs to communicate with each other with improved resource usage efficiency, reduced communication latency, and reduced beam search and signaling overhead.

Optionally, in any of the preceding aspects, communicating the signal comprises: transmitting, by the UE, the signal in the communication direction, wherein the communication direction is a transmission direction in which the signal is to be transmitted.

Optionally, in any of the preceding aspects, transmitting the signal comprises: transmitting, by the UE, the signal using a first beam that is beamformed according to the first beamforming direction associated with the first resource pool.

Optionally, in any of the preceding aspects, the method further includes: transmitting, by the UE, the signal in a deviated direction that is deviated from the first beamforming direction according to a predefined deviation. Optionally, in any of the preceding aspects, the method further includes: monitoring, by the UE in an opposite direction that is opposite to the first beamforming direction, the first resource pool for receiving a second signal from another UE.

Optionally, in any of the preceding aspects, the method further includes: receiving, by the UE, a response signal in a second resource in response to transmitting the signal, wherein the signal comprises a discovery signal.

Optionally, in any of the preceding aspects, communicating the signal comprises: receiving, by the UE, the signal in the communication direction, wherein the communication direction is a reception direction in which the signal is to be received. Optionally, in any of the preceding aspects, receiving the signal comprises: receiving, by the UE, the signal using a first beam that is directed in the first beamforming direction. Optionally, in any of the preceding aspects, the method further includes: transmitting, by the UE in an opposite direction that is opposite to the reception direction, a second signal using a resource of the first resource pool.

Optionally, in any of the preceding aspects, the method further includes: transmitting, by the UE, a response signal in a second resource in response to receipt of the signal, wherein the signal comprises a discovery signal.

Optionally, in any of the preceding aspects, the second resource is associated with the first resource.

Optionally, in any of the preceding aspects, the method further includes: obtaining, by the UE, an association between the first resource and the second resource.

Optionally, in any of the preceding aspects, the first resource pool is associated with a second resource pool comprising the second resource.

Optionally, in any of the preceding aspects, the method further includes: obtaining, by the UE, an association between the first resource pool and the second resource pool. Optionally, in any of the preceding aspects, the method further includes: determining, by the UE for communicating the response signal, the second resource according to the association. Optionally, in any of the preceding aspects, the beamforming direction comprises a direction with respect to an orientation of the UE.

Optionally, in any of the preceding aspects, the beamforming direction comprises a direction with respect to a geographical direction.

Optionally, in any of the preceding aspects, the resource pool configuration is obtained in a radio resource control (RRC) message, a medium access control (MAC) message, or a physical layer message.

Optionally, in any of the preceding aspects, the beamforming direction is specified by a spatial constraint configuration.

Optionally, in any of the preceding aspects, the spatial constraint configuration and the resource pool configuration are obtained by the UE in a same message or different messages.

Optionally, in any of the preceding aspects, the spatial constraint configuration further specifies a maximum number of transmissions performable using one of the plurality of resource pools.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:

FIG. lA illustrates a diagram of a communications system in an embodiment;

FIG. lB illustrates a diagram of a communication between two user equipments using beamforming in an embodiment;

FIG. tC illustrates a diagram showing conventional beam searching operations;

FIG. 2 illustrates a diagram of a beamforming direction in an embodiment;

FIG. 3A illustrates a diagram of an association configuration between a resource pool and a beamforming direction in an embodiment;

FIG. 3B illustrates a diagram of an implementation of an association configuration in an embodiment; FIG. 3C illustrates a diagram of an implementation of an association configuration in another embodiment;

FIG. 4 illustrates a diagram of an association configuration between resource pools and beamforming directions in another embodiment;

FIG. 5 illustrates a diagram of a vehicle-to-vehicle (V2V) communication in an embodiment;

FIG. 6 illustrates a diagram of showing V2V communications between UEs according to a resource pool configuration in an embodiment;

FIG. 7 illustrates a diagram of a V2V communication in another embodiment;

FIG. 8 illustrates a diagram of signal transmissions in an embodiment;

FIG. 9 illustrates a diagram of signal transmissions in another embodiment;

FIG. to is a flowchart of a transmission method in an embodiment;

FIG. 11 is a flowchart of a reception method in an embodiment;

FIG. 12 illustrates a diagram of a resource association in an embodiment;

FIG. 13 illustrates a diagram of a resource association in another embodiment;

FIG. 14 is a flowchart of a sidelink discovery method in an embodiment;

FIG. 15 is a flowchart of a sidelink discovery method in another embodiment;

FIG. r6 is a flowchart of a communication method in an embodiment;

FIG. t7 is a flowchart of a communication method in another embodiment;

FIG. r8 is a flowchart of a communication method in another embodiment;

FIG. t9 illustrates a diagram of a UE in an embodiment; and

FIG. 20 illustrates a block diagram of an embodiment processing system.

Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments of this disclosure are discussed in detail below. It should be appreciated, however, that the concepts disclosed herein can be embodied in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and do not serve to limit the scope of the claims. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

In communications between user equipments (UEs), such as in communications with a base station or base stations, or in Vehicle-to-eveiything (V2X) communications, initial beamforming and beam acquisition may rely on beam sweeping or beam searching. This is time consuming and may cause large communication latency, especially when UEs lack knowledge of locations or even existence of each other.

Embodiments of the present disclosure provide a method for device discovery and communications at high frequencies. The embodiments make use of directional beamforming to facilitate, or reduce the latency of, communications between UEs. Specifically, communications resources are associated with beamforming directions through configurations. UEs may use the resources to perform beamforming for transmission and/or reception in the associated directions. The embodiments enable the UEs to communicate with improved resource usage efficiency, reduced communication latency, and reduced beam searching and signaling overhead.

In one embodiment, a UE may obtain a resource pool configuration, where the resource pool configuration specifies a plurality of resource pools, and each of the plurality of resource pools is associated with a beamforming direction. The UE may select a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and also in accordance with a communication direction in which a signal is to be communicated by the UE. The UE may then communicate the signal in the communication direction using a first resource of the first resource pool. The communication direction is a direction in which a beam is to be formed for communication of the signal. The communication direction may be a transmission direction in which the signal is transmitted, or a reception direction in which the signal is received. The UE may transmit the signal in the transmission direction, or receive the signal in the reception direction. Details of the embodiments will be provided in the following.

Vehicle-to-everything (V2X) communications is playing a more and more important role in automotive industry. Vehicular communication technologies, such as dedicated short-range communication (DSRC) by IEEE and the long-term evolution - vehicular (LTE-V) by 3GPP have been developed for V2X communications. The third generation partnership project (3GPP) has also proposed the fifth generation (5G) new radio access technology (NR) V2X wireless communication with the goal of providing sG-compatible high-speed reliable connectivity for vehicular communications. Device-to-device (D2D) mode of communication is important in V2X communications. NR V2X communications is planned to support unicast communications, which will enable a vehicle to communicate with another specific vehicle, and groupcast communications, which will allow vehicles in a group of UEs to communicate.

At high frequencies (HF) such as at millimeter-wave (mmWave) bands also known as frequency range 2 (FR2), path loss is higher than in traditional cellular bands (typically below 3.5 GHz), and beamforming is necessary to establish a link between two UEs to compensate the high path loss.

In single-antenna communications through a single-input single-output (SISO) configuration, especially at conventional microwave frequencies, signals, in principle, are broadcast to all directions. With multi-antenna communications through a multiple-input multiple-output (MIMO) configuration, signals may be beamformed to certain directions and, as a result, may not reach all locations in vicinity with sufficiently good quality.

Beamforming techniques may generally vary based on different factors including the frequency. In particular, the beamforming of interest may be digital beamforming at low frequencies (LF), for example at frequencies below 6GHz or frequency range 1 (FRt), and may be analog or hybrid beamforming at high frequencies (HF), for example at frequencies above 6GHz or frequency range 2 (FR2). Beam management may, in general, comprise procedures such as transmission of beamformed signals, beam search, reception through receive beams, reporting beam indices and/or beam qualities, beam indication, and beam failure recovery procedures. FIG. lA illustrates a communications system too in an embodiment of the present disclosure. The system too may be viewed as a V2X communications system. The system too comprises at least two user equipments (UEs), such as UEs 13-17. A UE can be transported in, or can comprise part of, a vehicle in some examples. The multiple UEs 13-17 may communicate with each other using beamforming at high frequencies (HF), such as at millimeter-wave (mmWave) bands above 6 gigahertz (GHz), or frequency range 2 (FR2) as defined in the 5G NR standard. Each one of the UEs 13-17 may have at least one antenna, and at least one beam may be generated by the antenna. For example, the UE 13 has four antennas, including an antenna 131A at the left of the UE 13, an antenna 132A at the rear of the UE 13, an antenna 133A at the right of the UE 12, and an antenna 134A at the front of the UE 13. Each one of the antennas 131A-134A may be able to generate one or more beams 131B-134B. For instance, each of the antennas 161A-164A of the UE 16 is shown to be capable of generating five potential beams.

In the present disclosure, a beam of an antenna of a UE may refer to a directional radio pattern of the antenna at the time of transmission and/or reception. The orientation of the directional beam with respect to the UE and/or antenna may be changed over time. This process is called beamforming. The radio pattern may be generated by a processing unit of the UE through the adjusting of the parameters of the antenna, such as through phase shift differences between antenna elements. By changing the phase shift parameters, the UE may be able to direct the radio pattern to different directions at different times. This directing of the radio pattern may be performed both for transmission and for reception.

FIG. lB illustrates a diagram of a communication between two user equipments using beamforming in an embodiment of the present disclosure. The UE 13 may transmit signals via a transmit beam 132B. The transmit beam 132B is aimed toward the UE 14 in this example. The UE 14 may receive signals transmitted from the UE 13 via a receive beam 141A. The receive beam 141A in this example is aimed toward the UE 13. The receive beam 14 tA is therefore substantially opposite in orientation to the transmit beam 132B, generally about 180 degrees opposite in orientation or direction. When the transmit beam 132B and the receive beam 141A are substantially opposite and aligned, or at least partially overlapping, then a directional electromagnetic signal transmitted by the UE 13 will be received by the UE 14. The transmit beam 132B in a beamforming scenario comprises emitting an electromagnetic signal using an antenna or antennas, with the emitted signal having a lobe shape extending out from the antenna or antennas and along a transmission axis. Most of the electromagnetic energy is concentrated along the transmission axis, with signal power falling off significantly as a lateral distance from the transmission axis increases. The opposite of a transmit beam 132B is termed the receive beam 14 tA, although no electromagnetic beam is actually generated. A receive beam in beamforming terms is a proper orientation of an antenna (or antennas) so as to receive a directional signal.

For a directional signal to be exchanged between a transmitting device and a receiving device, the transmit beam of the transmitting device and the receive beam of the receiving device need to be nearly parallel and collinear, though not necessarily perfectly aligned. For example, in FIG. tB, when the transmit beam 132B and the receive beam 14 tA are sufficiently aligned, a signal can be transmitted from the UE 13 and received by the UE 14. As another example, if two signals are to be transmitted and/or received through similar or corresponding beams, they may be indicated to be quasi-collocated (QCL’ed) with respect to spatial parameters.

A UE may need to discover other UEs by beam searching. The UE may anticipate being discovered by other UEs in communications between user equipments. In the present disclosure, beam searching may refer to performing receive beamforming, with the receive beamforming comprising determining a proper antenna or reception orientation to best receive an expected transmission. The receive beamforming may be performed in a process for detecting and receiving signals, such as discovery signals. The receive beamforming may be performed in different directions spanning a coverage area wider than a single beam.

In a communications system in which UEs lack any knowledge of the locations of each other, and potentially, of the existence of each other, initial beamforming and beam acquisition needs to be performed blindly. Conventional beamforming and acquisition relies on beam sweeping. FIG. tC illustrates a diagram showing conventional beam searching operations between two UEs 15 and 16. The UE 15 may transmit a signal to receiving UEs that are able to receive the signal, and the UE 16 is detecting whether it receives any signal sent by another UE. Because both UEs 15 and 16 do not know each other’s location, exhaustive beam search needs to be performed between the two UEs.

The exhaustive beam search between the two UEs 15 and 16 may require the transmitting UE, i.e., the UE 15 to transmit, in synchrony with the receiving UE, i.e., the UE 16, signals such as discovery signals through every pair of transmit and receive beams of the UEs 15 and 16. For example, if the transmitting UE 15 can apply M transmit beams and the receiving UE 16 can apply N receive beams, a total of M*N discovery signals may need to be transmitted by the transmitting UE 15 in synchrony with the receiving UE 16. FIG. tC illustrates an example where M=3 and N=2. The UE 16 may receive, using two beams in different directions, six signals transmitted by the UE 15 using three beams in different directions, and determine a receiving beam direction based on the six signals for receiving signals from the UE 15. The UE 16 may send feedback information to the UE 15, based on which the UE 15 may determine a transmitting beam direction for transmitting signals to the UE 16.

However, the exhaustive beam search approach as illustrated in FIG. tC are disadvantageous for at least two reasons. First, in a practical communications system, the values of M and N may be much larger, and beams of an antenna may span a larger angular area than what is illustrated in FIG. tC, which may result in an unnecessarily long time for an exhaustive beam search. Second, UEs may need further coordination to know the values of M and N, in order to determine when an exhaustive beam search is complete. This requires additional signaling overhead. In addition, the additional signaling generally requires some form of coordination between a transmitter and a receiver, and thus is more difficult to achieve in a decentralized communications system, such as a V2X system. Therefore, it is desirous to develop methods for performing beam acquisition for V2X systems at high frequencies. The beam acquisition process is needed for both discovery and communication.

Embodiments of the present disclosure provide systems and methods for device discovery and communications at high frequencies in a V2X communications system. The embodiments make use of directional beamforming to facilitate, or reduce the latency of, communications between UEs such as those in the system too. Specifically, the embodiments of the present disclosure provide a constrained beamforming approach in which resources are associated with directions through configurations. UEs may use the resources to perform beamforming for transmission and/ or reception of messages in the associated directions. The UEs may be synchronized with each other, e.g., based on applicable methods in the art.

One advantage of the embodiments is that UEs are able to know beamforming directions for discovery/ communication and, thus, are able to reduce the set of directions they send and search for signals such as discovery signals, hence reducing beam search overhead compared to the aforementioned exhaustive beam search approach.

Some embodiments are described with an emphasis on discovery as an example. The embodiments of the present disclosure are however applicable“as is” for broadcast communications, groupcast communications, and unicast communications, including cases of communication without a feedback from the receiver.

In the disclosure, the terms of “message” and“signal” are used interchangeably. The terms of“discovery message” and“discovery signal” are used interchangeably. The terms of “beamforming direction”, “direction” and “transmitting direction” are used interchangeably. The difference between these terms will be provided when needed.

In some examples, HF and low frequencies (LF) may simply refer to high frequencies such as FR2 and low frequencies such as FRr, respectively. Also, the terms“at LF” and “at HF” may be used as a short form for“at an LF band” and“at an HF band,” respectively. Therefore, it should be appreciated that the terms LF and HF may refer to certain bands at low or high frequencies and may not necessarily apply to all the bands at low or high frequencies.

A UE typically has at least one antenna for transmitting and receiving signals. Some UEs may include multiple antennas. For example, both of the UEs 14 and 17 in the figure have six antennas, and the UE 15 has eight antennas. Multiple antennas at a same side of the UE may have same orientations, such as the antennas 14 lA and 146A at front of the UE 14 have the same orientation. The antennas at each other side of the UE 14 can have the same orientation as well. In other cases, multiple antennas at a same side of the UE may have different orientations. For example, the antenna 175A at front of the UE 17 has a left deviation angle from the center of front, and the antenna 176A at front of the UE 17 has a right deviation angle from the center of front. Thus, the antennas 176A and 177A have different orientations.

Alternatively, in some examples, the antennas mounted on the UEs 13-17 as illustrated may be implemented as an antenna array or an antenna panel, which may comprise a set of multiple connected antennas, possibly through phase shifters for beamforming, which work together as a single antenna to transmit or receive radio signals.

A UE with multiple antennas may be able to use different antennas for different purposes at a given time. Not all antennas of a UE may be available at a given time for participating in a communication with other UEs. For example, some antennas may be used to communicate data as scheduled. Some antennas may be turned off to save power. Some antennas may be used for receiving synchronization signals from the network, and so on. The number of antennas of a UE may be a UE feature or capability communicated prior to the communication or discovery process. The methods of using multiple UE antennas may be a UE implementation, controlled by the network, determined by connections such as sidelink connections, and so on.

If multiple antennas are available at a time to participate in a communication or a discovery process, a subset of the antennas may be used for transmissions and another subset may be used for reception at a given time. As explained in the aforementioned examples, this includes using an antenna (or antennas) to transmit a signal in a direction while using another antenna (or antennas) to search for signals from an opposite or different direction. Another example is using an antenna to transmit a signal in a direction while using another antenna to search for signals from the same or similar direction in order to reduce the probability of missing a signal due to the half-duplex constraint.

Optionally, the UEs 13-17 may separately communicate with a base station 19 through links 103-107. For example, the UEs 13-17 may receive control messages such as configuration messages from the base station 19. The UEs 13-17 may also receive data from the base station 19, and transmit control messages or data to the base station 19.

In embodiments of the present disclosure, the UEs 13-17 may comprise a terminal, a mobile station, a subscriber unit, a station, or a terminal equipment. These UEs may be a cellular phone, a personal digital assistant, a modem, or a pad/tablet device. With the development of communications technologies and Internet of Things (IOT), any mobile device that can access a wireless network and communicate with network side, or communicate with other devices directly or indirectly, could be the UEs 13-17 in embodiments of the present disclosure. For example, UEs 13-17 could be a vehicle that can support vehicle-to-everything (V2X) communication. As shown in FIG. tA, the UEs 13-15 are vehicles that are moving substantially in one direction on a road 12A. The UEs 16 and 17 are vehicles that are moving in the same and/ or different directions on a road

12B.

It is noted that the number of UEs, the quantity of antennas, the quantity of beams of each UE, and the location and direction of the antennas and the beams in the system too are just examples in one embodiment of the present disclosure, and it is not limited to these examples.

In embodiments of the present disclosure, resource pools are configured to a UE, such as the UEs 13-17, for communicating with other one or more UEs. Each one of the resource pools may be associated with a beamforming direction, so that the UE may choose a resource pool in accordance with a direction matched to the beamforming direction, or the UE may select a beamforming direction in accordance with a resource pool associated with the beamforming direction. A UE communicating in a selected resource pool performs beamforming in a beamforming direction associated with the selected resource pool.

A resource pool may be configured in accordance with one or multiple attributes such as a service type, UE location, proximity information, and so on, so that different needs of UEs can be accommodated, e.g., different quality of service (QoS) requirements, such as discovery or connection latency, different message sizes, different density of UEs interested in a particular service. The resource pools may comprise resource pools for transmission of signals and/or resource pools for reception of signals. The resource pools may be further partitioned into sub-resource pools. In the embodiments of the present disclosure, the terms of “resource pool” and “sub-resource pool” may be used interchangeably, as they both represent a set of resources and other associated parameters. Any difference between them is a matter of terminology and possibly a configuration hierarchy that is not significant while common principles apply.

A resource pool comprises at least one of time resources, frequency resources, or code resources that can be used in communications exchanged between UEs. In some examples, the time resource may be represented by parameters such as a time offset for a starting point in time, a periodicity for a periodic or semi-persistent allocation, time allocation parameters such as a time allocation bitmap, or a number of repetitions of instances in the case that the allocation is semi-persistent. The frequency resources may be represented by parameters such as a starting point in frequency, an ending point in frequency or a bandwidth or a frequency allocation bitmap. The code resources may be represented by parameters such as a pseudo-random sequence seed or an index to a codebook of spreading sequences. The resource pools may also include spatial constraints or spatial resource parameters. The spatial constraints specify beamforming information, such as beamforming direction, associated with the resource pools. The spatial constraints may be needed where beamforming, e.g., digital beamforming, analog beamforming, or hybrid beamforming, is employed. Details of spatial constraints will be provided later in the disclosure.

Table t below shows types of parameters that a resource pool configuration may include. A resource pool configuration may be a configuration specifying or including one or more of the parameters in Table l.

Table 1

The types of parameters that a resource pool may include may depend on a type of an air interface as well as an operating frequency band. For example, time resources may be needed for any air interface or frequency band, unless the resource pool is a dedicated channel in a frequency and/or a code domain. Frequency resources may be needed in a frequency-division-based air interface such as orthogonal frequency-division multiplexing / multiple-access (OFDM/OFDMA). Code resources may be needed in a code-division-based air interface such as code-division multiple-access (CDMA), but they may also be used for multiple-access in non-CDMA-based air interfaces.

In embodiments of the present disclosure, a beamforming direction may determine a propagation direction of a signal, such as a transmission direction of a signal or a reception direction of a signal. That is, when a UE obtains information of such beamforming direction, then the UE knows that a signal is to be transmitted towards, or received from, such direction. The beamforming direction also refers to as a direction of a beam in which a signal needs to be transmitted. The beam may be a transmit beam in which the UE transmits a signal, or a so-called "receive beam" where an antenna or antennas of the UE are oriented and/or configured to receive a signal from a particular orientation with respect to the antenna or antennas.

That is, the beamforming direction refers to a direction in which one or more beams are formed for communicating signals.

The beamforming direction associated with a resource pool may be notified to a UE in a spatial constraint configuration. The spatial constraint configuration specifies a spatial constraint, such as a beamforming direction, associated with a resource pool. When the UE receives the spatial constraint configuration, the UE may determine the beamforming direction. Furthermore, the UE may select a resource pool associated with a beamforming direction that matches a transmission direction anticipated by the UE. The spatial constraint configuration may also be referred to by terms such as“direction information”,“angle information”,“spatial information”, or“spatial parameters” that may represent or specify the transmission or reception direction of signals in a space, etc. These terms are generally synonyms and may be used interchangeably according to the context. For example, direction information for beamforming may be communicated through parameters in a radio resource control (RRC) configuration referred to as spatial parameters.

In some examples, the beamforming direction may be determined according to an orientation of a UE (vehicle UE or V-UE) itself, such as a front of the UE, a rear of the UE, a left of the UE, or a right of the UE. This is useful for vehicular communications because vehicles change orientation possibly at a much lower pace compared to, for example, a handheld device. Also, vehicles’ orientations in an area are highly correlated in typical scenarios, for example, on a highway, where practically all the vehicles in an area face a substantially same direction. The terms of“UE”,“V-UE” and“vehicle” are used interchangeably throughout the disclosure. In order to implement the embodiments of the present disclosure, the spatial constraint configuration may comprise parameters and values that are defined by a relevant standard. In the 5G NR Release 15 standard, spatial information may be communicated through a type of quasi-collocation (QCL) called QCL Type D. This type of QCL, also called spatial QCL, provides spatial information by making a reference to a signal such as a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB). In the embodiments of the present disclosure, signals communicated may comprise a discovery signal or a discovery report. Alternatively, in order to provide the beamforming direction for a UE with respect to an orientation of the UE on a two-dimensional (2D) plane, a direction parameter may specify the orientation of the UE on the horizontal plane, such as the front, rear, left, or right of the UE. Alternatively, the direction parameter may also specify an angle on the horizontal plane with respect to a reference point, such as the front of the UE, in a direction such as clockwise. Then, for instance, the UE’s front, right side, rear, and left sides can be specified by values associated with 0/360, 90, 180, and 270 degrees, respectively. Or the direction parameter may specify a value associated with any angle between o to 360 degrees. The granularity of the angle values may be defined by the standard or configured by the network. For example, a two-bit value may be used to specify a value from the set {0/360, 90, 180, 270}, and a three-bit value may be used to specify additional four directions in between those values. The reference point and the plane may also be defined by the standard or configured by the network.

In some other examples, the beamforming direction may comprise a geographical direction. Namely, the beamforming direction may be determined in accordance with the geographical direction. The geographical direction may be determined with respect to the established magnetic pole (or other fixed geographical reference point), such as north (N), south (S), west (W), or east (E). Alternatively, the geographical direction may also comprise northeast (NE), northwest (NW), southeast (SE), or southwest (SW). Thus, the geographical direction is also referred to as a navigation direction. This option is useful for other scenarios, such as urban environments and non-vehicular sidelink use cases. Similarly, in order to provide the beamforming direction for a UE with respect to geographical directions on a two-dimensional (2D) plane, a direction parameter may specify a geographical direction such as north, south, west, or east, i.e., the direction parameter can specify a transmission or reception direction with respect to established geographic directions. Alternatively, the direction parameter may specify an angle on the horizontal plane with respect to a reference point such as north in a direction such as clockwise, as customary for“bearing” information in navigation. Then, for instance, north, east, south, west may be specified by values associated with 0/360, 90, 180, and 270 degrees, respectively. Or the direction parameter may specify a value associated with any angle between o to 360 degrees. The granularity of values for an angle parameter may be defined by the standard or configured by the network. For example, a two-bit value may be used to specify a value from the set {0/360, 90, 180, 270}, and a three-bit value may be used to specify additional four directions in between those values. The reference point and the plane may, as well, be defined by the standard or configured by the network.

In some embodiments, direction information may be provided by a combination of the above types of information, i.e., orientation of the UE and geographical direction. Then, an additional configuration parameter may be used to distinguish between a direction with respect to the orientation of the UE and a direction with respect to geographical directions.

FIG. 2 illustrates a diagram 200 showing beamforming direction in an embodiment of the present disclosure.

In a case where the beamforming direction is determined in accordance with a vehicle UE’s orientation (or referred to as UE orientation), such as front of a vehicle 23 in an example 200A (also referred to as a status of the vehicle 23) of FIG. 2, then the vehicle 23 may transmit signals in a beam located in a coverage scope 2D1. Similarly, for the direction of rear, the vehicle 23 may transmit signals in a beam located in a coverage scope 2D2. The coverage scope of different vehicle orientations could be overlapped, such as the scope 2D1 and the scope 2D3 may have an overlapped scope 2D5, which means that the scope 2D5 may be covered by beamforming when the vehicle transmits signals by using antennas that are mounted on either front or left.

For a vehicle oriented east-west, or north-south, the vehicle’s orientation may overlap with the geographical direction. For example, in the status 200A of the vehicle 23, the beamforming direction determined in accordance with the UE orientation is same as the beamforming direction determined in accordance with a geographical direction. For instance, the front of the vehicle 23, i.e., the scope 2D1, is same as east in a geographic sense. The vehicle 23 knows which antenna is mounted on the front, rear, left or right of the vehicle 23. For instance, the position information of the mounted antennas of the vehicle 23 may be stored by the UE or by the vehicle 23 itself. Therefore, when the vehicle 23 needs to transmit signals towards the front of the vehicle, the vehicle 23 may look up the stored information to select the antenna mounted at the front of the vehicle 23.

With moving to another status such as status 200B in which the vehicle 23 is heading to the northeast, or to a status 200C in which the vehicle 23 is heading to the north, the beamforming direction determined according to the UE orientation remains unchanged compared to the UE’s own orientation. For example, the coverage scope 2D1 of the beamforming direction is still on the front of the vehicle. In such situation, when the vehicle 23 still needs to transmit signals towards the front, the vehicle 23 still selects the antenna mounted on the front of the vehicle 23. Namely, the antenna used for the transmission towards the front does not change. If the heading of the vehicles 23 changes, in the case a beamforming direction is determined in accordance with geographical directions, the antennas used for transmission towards a specific beamforming direction may change. For example, in the status 200A, the antenna mounted to the rear of the vehicle 23 directs towards the west. In the status 200B, an antenna towards the west changes to the antennas mounted to the rear and the left of the vehicle 23. In the status 200C, an antenna towards the west changes to the antenna mounted on the left of the vehicle 23.

In an example, in the case a beamforming direction is determined in accordance with geographical directions, the vehicle 23 may determine the antennas towards a specific beamforming direction according to the position information of antennas mounted on the vehicle 23 and a geographical direction of the vehicle 23. Various methods may be used to determine the geographical direction of the vehicle 23, such as using a magnetic sensor that may determine the heading direction of the vehicle. The vehicle 23 then can determine either an antenna coverage or a beam towards a specific geographical direction.

Resource pools are associated with beamforming directions. For example, resources may be configured with four instances (or resource pools) (Pi, P2, P3, P4) occupying physical resources in slots (Ri, R2, R3, R4) respectively. Then, four beamforming directions (Di, D2, D3, D4) may be associated with the four instances (Pi, P2, P3, P4) respectively, e.g., through identifiers (IDs) of configurations or instances of a configuration. In some embodiments, a beamforming direction may not be directly associated with a resource pool, but may instead be provided as a function of physical resources, e.g., a function of time and/or frequency. For example, the beamforming directions (Di, D2, D3, D4) may be associated directly with the four slots (Ri, R2, R3, R4) respectively, e.g., through a function of indices of the physical resources such as slots or resource blocks (RBs). Then, a UE can combine each instance (resource pool) with a beamforming direction that is associated with a physical resource occupied by the resource pool. As a result, the UE may obtain the beamforming direction in accordance with a function of physical resources (i.e., association between the beamforming and the physical resources).

FIG. 3A illustrates a diagram of an association configuration 300 between resource pools and beamforming directions in communications between UEs in an embodiment of the present disclosure. A group of time (t) - frequency (f) resources comprises at least one resource pools, such as resource pools 310-340. Each resource pool is associated with a beamforming direction, which is represented by an arrow 311-341 as shown in FIG. 3A in some examples. The association configuration300comprises a resource configuration of the at least one resource pool and a spatial constraint configuration specifying the direction associated with the at least one resource pool separately. In this example, each of the resource pools 310-340 occupies different time resources, and may occupy the same frequency resources.

In one example, the beamforming direction is determined based on an orientation of a UE. In this case, ach of resource pools 310-340 is associated with a direction defined according to the orientation of the UE. For example, a resource pool 310 is associated with an arrow 311, which represents the front of the UE. A resource pool 320 is associated with an arrow 321, which represents the rear of the UE. A resource pool 330 is associated with an arrow 331, which represents the right of the UE. A resource pool 340 is associated with an arrow 341, which represents the left of the UE.

FIG. 3B illustrates a diagram of an implementation of the association configuration 300 in which a resource pool is associated with an orientation of the UE 13 as illustrated in FIG. lA in an embodiment of the present disclosure. In an example, when the UE 13 needs to transmit towards the right of the UE 13, the UE may select the resource pool 330 that is a resource pool for transmitting to the right according to the association configuration 30. Thus, the UE 13 may further select a resource from the resource pool 330 and transmit signals towards the right of the UE 13 via a beam 133B. In this example, no matter which geographical direction the UE 13 is heading to, the UE 13 would use the resource selected from the resource pool 330 to transmit the signals towards the right of the UE 13.

Alternatively, in another example, each of the resource pools 310-340 may be associated with a geographical direction. In one example, the resource pool 310 may be associated with the west, which is represented by the arrow 311. The resource pool 320 may be associated with the east, which is represented by the arrow 321. The resource pool 330 may be associated with the north, which is represented by the arrow 331. The resource pool 340 may be associated with the south, which is represented by the arrow 341.

FIG. 3C illustrates a diagram of an implementation of the association configuration 300 in which a resource pool is associated with a geographical direction in an embodiment of the present disclosure. In an example, when the UE 13 needs to transmit towards the north, the UE 13 may select the resource pool 330 that is a resource pool for transmitting to the north according to the association configuration 30. Thus, the UE 13 may further select a resource from the resource pool 330 and transmit signals towards the north via the beam 133B.

Accordingly, when the UE 13 needs to transmit towards or receive from a specific direction, the UE 13 may determine a resource pool corresponding to the specific direction in accordance with a spatial constraint configuration (specifying association between resource pools and beamforming directions). Then the UE 13 may use a resource from one of the resource pools 310-340 for communication with other UEs. The UE 13 then communicates with other UEs through a beam in the direction corresponding to a resource pool to which the resource belongs.

The beamforming directions (the spatial constraints) may be determined using different approaches, such as determined with respect to the surrounding environment, without departing from the principle and spirit of the disclosure. For example, the beamforming directions may be determined according to cardinal directions (north, east, south, west), or navigation directions such as a number in the range of [o, 360] clockwise from a direction (e.g., the north).

FIG. 4 illustrates a diagram of an association configuration 400 between resource pools and directions in another embodiment of the present disclosure. UE antennas may be able to direct beams to more directions than a limited set of directions determined by a spatial constraint configuration. For example, a front antenna of a vehicular UE (V-UE) may be able to transmit to multiple directions to the front of the V-UE and span a certain angular area. In the case that each beam is not sufficiently wide to cover the whole angular area in front of the V-UE, it may have to sweep the angular area through multiple beams over time. As a result, the V-UE may choose to transmit multiple messages through different beams, essentially sweeping an angular area, in order to increase the probability of being detected or discovered by another V-UE in the vicinity.

As illustrated in FIG. 4, a group of time-frequency resources comprises four resource pools 410-440. Each resource pool is associated with multiple directions. The multiple directions may be used to transmit multiple messages. The multiple directions are represented by arrows as shown in FIG. 4. In one example, a resource pool 410 is associated with an arrow 411 corresponding to a first message 412 to be sent, an arrow 413 corresponding to a second message 414, and an arrow 415 corresponding to a third message 416. The directions represented by the arrows 411, 413, and 415 could be determined based on the orientation of the V-UE itself. For example, the arrow 413 represents a center of the UE front, the arrow 411 represents a left deviation from the center of the UE front, and the arrow 415 represents a right deviation from the center front. The left deviation and the right deviation may be configured by determining an angle value in one example. Similarly, resource pools 420, 430, and 440 are associated with multiple directions separately. The resource pool 420 associates with directions 421, 423, and 425 that are corresponding to messages 422, 424 and 426 separately. The resource pool 440 associates with directions 431, 433, and 435 that are corresponding to messages 432, 434 and 436 separately. The resource pool 440 associates with directions 441, 443, and 445 that are corresponding to messages 442, 444 and 446 separately. All directions associated with the resource pools 420, 430, and 440 may be determined based on the orientation of the V-UE itself.

Alternatively, in another example, the directions associated with each of the resource pools 410-440 may be determined with respect to a geographical direction.

Accordingly, when the UE needs to transmit multiple messages, such as messages 412, 414, and 416, the UE may transmit messages 412, 414, and 416 through beams towards different directions.

In an alternative embodiment, information such as a maximum angular deviation from a determined direction (such as front, rear, right and left), a maximum number of transmissions of messages by a UE in one resource pool, and so on may also be determined by the spatial constraint configuration.

It is noted that the hardware constraint of a time-division between swept beams may be applicable to each antenna of a UE, so a UE with multiple antennas in the front, for example, may be able to transmit messages to different directions simultaneously by using different antennas. Then, a maximum number of transmissions may be applicable to a UE or, alternatively, to each antenna of a UE.

In embodiments of the present disclosure, based on a resource pool configuration and a spatial constraint configuration, a UE may need to schedule a transmission of a signal and/or receiving (searching) for signals during the period of a resource pool for each of its available antennas.

In an example where a UE has obtained the resource pool configuration and the spatial constraint configuration as shown in FIG. 3A, and the directions are determined in accordance with the orientation of the UE, during a time interval of the resource pool 310 (time resources of the resource pool 310), antennas in the front of the UE may be used to transmit messages while antennas in the rear of the UE may be used to receive (i.e., search for) messages. During a time interval of the resource pool 320, antennas in the rear of the UE may be used to transmit messages while antennas in the front of the UE may be used to receive messages. During a time interval of the resource pool 330, antennas on the right side of the UE may be used to transmit messages while antennas on the left side of the UE may be used to receive messages. During a time interval of the resource pool 340, antennas on the left side of the UE may be used to transmit messages while antennas on the right side of the UE may be used to receive messages.

When multiple resource pools are configured for a UE, and each of the resource pools is associated with a beamforming direction, the UE may transmit and/or receive signals in a resource pool selected based on the spatial constraint configuration towards a specific direction. Thus, the UE may reduce the beam search overhead and improve the resource efficiency. The communications between user equipments may experience a lower latency as a result.

In some examples, beamforming directions may be associated with a resource pools in a round robin way as long as the association can cover different directions. Some directions may be given more resources. For example, resource pools may be associated with directions in an order of front, rear, right, front, rear, and left. According to the configuration in this example, a vehicle may have more possibilities to establish sidelinks with other vehicles in a highway scenario. It is noted that, the embodiments of the present disclosure do not limit to this example. The association of directions with resource pools may vary with the positions of UEs, surrounding environments of the UEs, or the numbers of the UEs in a specific region, and so on.

FIG. 5 illustrates a diagram of a vehicle-to-vehicle (V2V) communication 500 in another embodiment of the present disclosure. FIG. 5 shows vehicles 53-55 that have a substantially same moving direction on a road 52A. A resource pool configuration 502 that is similar to the configuration as shown in FIG. 3A may be applied for communications between the UEs (vehicles) 53-55. The vehicles are similar to the respective vehicles 13-15 that have a substantially same moving direction on road 12A in the system too. In the scenario of road 52A, multiple vehicles change orientation possibly at a much lower pace, and vehicles’ orientations are highly correlated in typical scenarios, practically all the vehicles in an area face the substantially same direction. The vehicles may have desires to communicate with vehicles located ahead of them or behind of them. A vehicle may need to discover other vehicles by beam searching, and the vehicle may also anticipate to be discovered by other vehicles in the V2V communication. The vehicle may be configured to transmit signals to other vehicles while receiving signals from other vehicles. Thus, a configuration with respect to transmission of signals and a configuration with respect to reception of signals may be configured for the vehicle. For example, a configuration502 used for transmission of signals as illustrated in FIG. 5 may be configured for vehicles 53-55. The configuration502 comprises a resource pool configuration for resource pools 510, 515, 520 and 525 and a spatial constraint configuration specifying beamforming directions 511-526 associated with the resource pools 510-525, respectively. In this example, the beamforming directions 511-526 are determined in accordance with the orientation of a vehicle. In the configuration502 used for the transmission of signals, the beamforming direction 511 represents a front of a vehicle, the beamforming direction 516 represents a rear of the vehicle, the beamforming direction 521 represents a right of the vehicle, and the beamforming direction 526 represents a left of the vehicle. Thus, in the example as illustrated in FIG. 5, the resource pool 510 is configured for transmitting signals by a vehicle towards the front of the vehicle, e.g., a vehicle 54, while the resource pool 515 is configured for transmitting signals by a vehicle towards the rear of the vehicle, e.g., the vehicle 54. Meanwhile, the resource pool 510 is configured for receiving signals that are sent towards the rear of a vehicle 53, and the resource pool 515 is configured for receiving signals that are sent towards the front of a vehicle 55. The resource pool 520 is configured for transmitting signals by a vehicle towards the right of the vehicle, and the resource pool 525 is configured for transmitting signals by a vehicle towards the left of the vehicle.

When a UE wants to detect signals such as discovery signals from other UEs sent in a specific direction, it may listen to resources associated with a beamforming direction opposite the specific direction, using one or more receive beams directed in the specific direction. For example, when the UE 53 wants to detect signals sent by other UEs, e.g., the vehicle 54, towards the rear of the UE 53, the UE 53 listens to resources associated with a beamforming direction of front (i.e., the resource pool 510 in this example), through receive beams directed towards the rear of the UE 53, such as a beam 535. In this case, the vehicle 54 transmits signals using a resource from the resource pool 510 with a beamforming direction towards the front of the vehicle 54, e.g., in at least one beam 541 towards the front of the vehicle 54. The vehicle 53 may listen to resources in the resource pool 510 using the beam 535, for example, to search for the signals transmitted by the vehicle 54.

In another example, the vehicle 55 wants to detect signals sent by other UEs in its front, and it listens to resources in the resource pool 515 associated with a beamforming direction of rear, using one or more receive beams, e.g., 551. In this case, the vehicle 54 transmits signals using a resource from the resource pool 515 with a beamforming direction towards the rear of the vehicle 54, e.g., in at least one beam 545 towards the rear of the vehicle 54. The vehicle 55 may detect the signals sent by the vehicle 54 towards the rear of the vehicle 54. The vehicle 53 uses resource pool 510 to listen in at least one of beams 535 towards the rear of the vehicle 53, and to search for signals sent from the vehicle 54 in at least one of beams 541 towards the front of the vehicle 54. Similarly, the vehicle 55 uses resource pool 515 to listen in at least one of beams 551 towards the front of the vehicle 55, and to search for signals sent from the vehicle 54 in at least one of beams 545 towards the rear of the vehicle 54.

A UE may be configured with one of a configuration with respect to transmission of signals and a configuration with respect to reception of signals, and then the UE may deduce the other configuration according to a predetermined rule that an opposite communication has an opposite beamforming direction. That is, when a spatial constraint or the beamforming direction may be determined for transmission, based on which the UE may obtain a dual of the spatial constraint for reception. If the UE has obtained the spatial constraint for a signal transmission, and the UE needs to transmit a signal to other UEs and also needs to receive a signal sent from other UEs, the UE may obtain the spatial constraint for the reception based on the spatial constraint for a signal transmission. For example, the dual of transmission towards the front is reception from the rear, and vice versa. The spatial constraint may specify a beamforming direction for transmission, and the dual of the spatial constraint may specify a direction for receiving, which is opposite the beamforming direction for transmission.

For example, if a UE gets the configuration502 for transmission of signals as illustrated in FIG. 5, the UE can determine that the UE may receive signals from other UEs on the same resource pool towards a beamforming direction opposite to the beamforming direction associated with the resource pool. Taking the resource pool 510 as an example, in configuration 500, where the resource pool 510 is associated with a front of the UE, the UE needs to transmit signals on a beam towards the front of the UE. Then, the UE may determine that the UE can receive signals on a beam towards the rear of the UE. Therefore, the UE does not need to be configured with two configurations for transmission of signals and reception of signals. Instead, the UE may obtain two configurations by only getting one configuration. Accordingly, the signaling overhead could be reduced and the latency can be further decreased.

In some examples, a transmission between vehicles may not occupy a whole resource pool. Transmitting in a transmission direction according to a spatial constraint and receiving in a reception direction according to a dual of the spatial constraint by a vehicle because the associated resource pools used, e.g., the resource pools 510 and 515 (or 520 and 525) are configured on different time resources. This may be the case for half-duplex communications, where each antenna performs either transmission or reception of signals at a particular band, but not performing transmission and reception simultaneously. Each vehicle or vehicle’s antenna may apply one or multiple beams for transmission of a message or searching for messages using a resource pool.

The configuration502 as illustrated in FIG. 5 shows that the resource pools 510-525 include different time resources, i.e., including different time intervals that are non-overlapping. With such a configuration, at a particular time belonging to a particular resource pool, UEs know in which direction they can transmit at this particular time, based on the beamforming direction associated with the particular resource pool. Consequently, each of the UEs knows transmission direction of the other UEs at the particular time, and thus knows in which direction to listen to signals from the other UEs. For example, at a time Tt in the resource pool 510, each of the UEs 53-55 knows that it can transmit towards its front using a resource in the resource pool 510, and can listen to signals from other UEs towards its rear. In another example, at a time T2 in the resource pool 520, each of the UEs 53-55 knows that it can transmit towards its right using a resource in the resource pool 520, and can listen to signals from other UEs towards its left.

An illustration is provided in FIG. 6 in association with the example of FIG. 5. FIG. 6 illustrates a diagram 600 showing the UEs 53-55 communicating using the configuration 502 as illustrated in FIG. 5. The vehicles 53, 54 and 55 select and use resources from the resource pools configured for them for transmitting signals. During a time interval of the resource pool 510, the vehicles 53-55 use their front antennas for transmitting signals and use their rear antennas for searching for signals. Each vehicle may perform analog beamforming, possibly to or from different directions, for transmission or reception of the signals. The vehicle 53 may receive signals from the vehicle 54 and vehicle 55, while the vehicle 54 may receive signals from the vehicle 55. It is possible for vehicle 54 to receive signals from the vehicle 53 that are scattered by the environment or by other vehicles. However, due to higher directivity of the signals at higher frequencies, the scattered signals may have been weakened significantly when arriving at the vehicle 54, which is desired and intended by the currently proposed spatially-constrained beamforming method.

Later, during the time interval of the resource pool 515, the vehicles 53-55 use their rear antennas for transmitting signals and use their front antennas for searching for signals. The vehicle 55 may receive signals from the vehicle 54 and the vehicle 53, while the vehicle 54 may receive signals from the vehicle 53. Similarly to before, it is possible for the vehicle 54 during this time interval to receive weakened signals from the vehicle 55 that are scattered by the environment.

In some examples, a transmission between vehicles does not generally occupy a whole resource pool. The two transmission-reception pairs associated with the resource pools 510 and 515 do not occur simultaneously in this example because the resource pools 510 and 515 are configured on different time resources. This may be considered a typical case because of half-duplex constraints that allow each antenna to perform either transmission or reception of signals at a particular band, but not both simultaneously. Alternatively, each vehicle or vehicle’s antenna may apply multiple beams for transmission of a message or searching for messages when using a spatial constraint configuration such as FIG. 4.

FIG. 7 illustrates a diagram of a V2V communication 700 in another embodiment of the present invention. 502 In this example, a configuration with respect to transmission of signals and/or a configuration with respect to reception of signals may be configured to vehicles such as vehicles (V-UEs) 73-77. FIG. 7 illustrates an example of transmission and reception of signals by UEs that are provided spatial constraints with respect to geographical directions. In FIG. 7, a resource pool configuration 702 is configured for the UEs 73-77, which includes four resource pools 710-725 associated with different directions 711-726. The directions 711-726 in the configuration702 are determined in accordance with the geographical directions. Particularly, the direction 711 represents the west, the direction 716 represents the east, the direction 721 represents the north, and the direction 726 represents the south in the configuration 702 with respect to transmission of signals.

In the scenario as shown in FIG. 7, the V-UEs 73-77 are moving on roads 71 and 72. The V-UEs 73-77 may have different moving directions. The spatial constraint configuration may be configured to each UE. Taking the vehicle 74 as an example as illustrated in FIG. 7, the resource pool 710 is configured for the vehicle 74 to transmit signals towards the west, while the resource pool 715 is configured for the vehicle 74 to transmit signals towards the east. Meanwhile, the resource pool 710 is configured for the vehicle 73 to receive signals towards the east (e.g., receiving signals transmitted by the vehicle 74 using the resource pool 710), and the resource pool 715 is configured for the vehicle 75 to receive signals towards the west (e.g., receiving signals transmitted by the vehicle 74 using the resource pool 715. Similarly, the resource pool 720 may be configured for the vehicle 74 to transmit signals towards the north and the resource pool 725 is configured for the vehicle 74 to transmit signals towards the south. Meanwhile, the resource pool 720 is configured for the vehicle 76 to receive signals towards the south, and the resource pool 725 is configured for a vehicle 77 to receive signals towards the north.

With the configuration 702, during a time interval of a resource pool, each of the UEs 73-77 may perform transmissions with transmit beams formed towards a first direction associated with the resource pool, and may receive transmissions with receive beams formed towards a second direction opposite to the first direction.

FIG. 8 illustrates a diagram 800 showing signal transmissions during the time interval of the resource pool 710 in the example of FIG. 7. Transmissions of signals are beamformed towards the west and, hence, the vehicles 73-77 use receive beamforming towards the east. Therefore, vehicles oriented east-west such as vehicles 73-75 may use their front and rear antennas for discovery or communications, while vehicles oriented north-south such as the vehicles 76 and 77 may use their side antennas for discovery or communications during the time interval of resource pool 710. Similarly, in the example during the time interval of the resource pool 715, the transmission of signals is beamformed towards the east and the vehicles use receive beamforming towards the west (not shown in the figure).

FIG. 9 illustrates a diagram 900 showing signal transmissions during the time interval of the resource pool 720 in the example of FIG. 7. Transmission of signals is beamformed towards the north and, hence, the vehicles use receive beamforming towards the south. Therefore, vehicles oriented north-south such as the vehicles 76 and 77 may use their front and rear antennas for communications, while UEs oriented east-west such as the vehicles 73-75 may use their side antennas for communications during the time interval of the resource pool 720. Similarly, in the example during the time interval of the resource pool 725, the transmission of signals is beamformed towards the south and the UEs use receive beamforming towards the north (not shown in the figure).

In the examples as shown in FIGS. 7-9, a UE may be configured with one of the configuration with respect to transmission of signals and the configuration with respect to reception of signals, and then the UE may deduce another configuration according to a predetermined rule that an opposite communication has an opposite beamforming direction. That is, the spatial constraint or the beamforming direction may be determined for transmission in which case the UE may obtain the dual of the spatial constraints for reception. If the UE has obtained the spatial constraint for a signal transmission, and the UE needs to transmit a signal to other UEs and also needs to receive a signal sent from other UEs, the UE may obtain the spatial constraint for the reception based on the spatial constraint for a signal transmission. For example, the dual of transmission towards the front is reception from the rear, and vice versa.

For example, if a UE gets the configuration 702 for transmission of signals as illustrated in FIG. 7, then the UE can determine that the UE may receive signals from other UEs on the same resource pool towards a beamforming direction opposite to the beamforming direction associated with the resource pool. Take the resource pool 710 as an example, in configuration 702, where the resource pool 710 is associated with the west, the UE needs to transmit signals on a beam towards the west. Then, the UE may determine that the UE can receive signals on a beam in the opposite direction, i.e., the east. Therefore, the UE may deduce a configuration for reception of signals from the configuration 702. Therefore, the UE does not need to be configured with two configurations for transmission of signals and reception of signals. Instead, the UE may obtain two configurations by only getting one configuration. Accordingly, the signaling overhead could be reduced.

Alternatively, each vehicle or vehicle’s antenna may apply multiple beams for transmission of messages or searching for messages when using a spatial constraint configuration such as illustrated in FIG. 4.

FIG. 10 is a flowchart of a transmission method 1000 between UEs in an embodiment of the present disclosure. In this embodiment, a transmission of signals such as a discovery signal in a sidelink discovery is described hereinafter. The method rooo may be indicative of operations performed by a UE, such as one of the V-UE t3-t7, or 73-77.

In operation roro, a UE obtains a resource pool configuration.

The resource pool configuration may indicate at least one resource pool. As described above, the resource pool may refer to a resource pool including at least one of time resources, frequency resources, or code resources. For example, the resource pool configuration may indicate four resource pools as illustrated in FIG. 3A or FIG. 4.

In an example, the resource pool configuration specifies a resource pool for discovery signals. The resource pool for discovery signals may also be referred to as a discovery resource pool (DRP).

In operation t020, the UE obtains a spatial constraint configuration for transmission of signals, such as a discovery signal.

The resource pool configured by the resource pool configuration may be associated with a direction in accordance with the spatial constraint configuration. The spatial constraint configuration may indicate the direction corresponding to each resource pool, such as the directions associated with each resource pool as shown in FIGs. 3 and 4.

In an example, in above operations 1010 and 1020, the resource pool configuration and the spatial constraint configuration may be obtained in one message or in separate messages such as control messages. The UE may obtain at least one message, which may be a radio resource control (RRC) message, a medium access control (MAC) message, or a physical layer message, where the at least one message includes the resource pool configuration and the spatial constraint configuration. The at least one message may be sent from a base station or another UE or a combination thereof. For example, the UE may receive an RRC message from the base station or another UE, and the RRC message includes the resource pool configuration and the spatial constraint configuration. The UE may receive a MAC message, where the MAC message includes the resource pool configuration and the spatial constraint configuration. Alternatively, the UE may receive a physical layer message, where the physical layer message includes the resource pool configuration and the spatial constraint configuration.

Alternatively, the resource pool configuration may be carried in an RRC message, and the spatial constraint configuration may be carried in a MAC message or a physical layer message. The resource pool configuration may also be carried in a MAC message, and the spatial constraint configuration may be carried in a RRC message or a physical layer message. In a different possible option, the resource pool configuration may be carried in a physical layer message, and the spatial constraint configuration may be carried in a RRC message or a MAC message.

In an example, one or multiple resource pools may be configured in a dedicated channel such as a physical sidelink discovery channel (PSDCH), or another channel, such as a control channel, e.g., a physical sidelink control channel (PSCCH), a shared/data channel, e.g., a physical sidelink shared channel (PSSCH), or a broadcast channel, e.g., a physical sidelink broadcast channel (PSBCH).

Alternatively, the operations 1010 and 1020 may comprise receiving the configurations in a control message, obtaining the configurations according to a pre-configuration defined by a standard, or a combination thereof. The obtaining may also comprise obtaining multiple such configurations, and selecting the one(s) (i.e., one or more configurations) associated with a location or velocity of the UE, a service type, and/or other attributes. For example, a pre-configuration and/or an RRC message may configure multiple resource pools in association with service types. Then, spatial constraints may be determined by lower layer messages in association with UE locations.

In an example, the UE may obtain such a resource pool configuration and the spatial constraint configuration in a message including fields as shown in Table 2 below.

Table 2

In Table 2, the direction may be determined with respect to the orientation of the UE. In the spatial constraint configuration, the value could be at least one of front, rear, left, or right. In this case, a resource pool can be associated with transmit beamforming towards the front of the UE while another resource pool can be associated with transmit beamforming towards the rear of the UE. Other resource pools can be associated with transmit beamforming towards either or both sides of the UE. Alternatively, the direction may be determined with respect to the geographical direction, such as at least one of west, east, north, or south. Then resource pools are associated with different geographical directions.

In another example, the UE may obtain the resource pool configuration and the spatial constraint configuration in a message as shown in Table 3 below.

Table 3

In Table 3, in addition to the beamforming direction for the signal transmission, the spatial constraint configuration may further comprise a maximum allowed deviation from the center angle, such as X degrees each side. X is a value that is equal to or larger than o, e.g., 45. The spatial constraint configuration may also comprise a maximum number of transmissions of signals such as discovery signals by the UE in one resource pool. Y represents the maximum number of transmissions of signals, and could be an integer larger than o. Table 3 shows a case that is described with respect to FIG. 4, where a UE may transmit multiple messages in a range in a direction. For example, the UE may transmit Y=3 messages using a resource pool, such as 410, with the 3 messages being sent towards the center of the UE front, in a direction that is to degrees deviated from the center of the UE front to the left of the UE, and in a direction that is to degrees deviated from the center of the UE front to the right of the UE.

Alternatively, in operation 1020, if the UE has obtained the spatial constraint for a signal reception, and the UE needs to transmit a signal to other UEs and also needs to receive a signal sent from other UEs, the UE may obtain the spatial constraint for transmission based on the spatial constraint for the signal reception, and vice versa.

In operation 1030, the UE determines a transmission direction for a signal that the UE wants to transmit.

The UE may determine the transmission direction according to the orientation of the UE. For example, in the scenario of the road 52A in FIG. 5, a vehicle such as the vehicle 54 may determine a transmission direction of a signal to be transmitted by the vehicle 54. For example, the vehicle 54 may want to communicate with other vehicles towards the front and the rear of the vehicle 54 itself. Thus, the vehicle 54 may determine that the transmission direction of a signal is front of the vehicle 54 or rear of the vehicle.

The transmission direction may be selected by the UE from a set of directions that have been associated with resource pools. For example, the UE may be configured with n resource pools, and the n resource pools are associated with m beamforming directions, where m is equal to or less than n. As an example, the m beamforming directions may include a set of directions in degrees, i.e., {0/360, 45, 90, 135, 180, 225, 270, 315}. The UE may select one of the set of directions for transmitting signals.

In operation 1040, the UE determines a resource pool based on the transmission direction, the spatial constraint configuration and the resource pool configuration.

The UE may select a resource pool in accordance with the transmission direction determined in the operation 1030 and the association between the transmission direction and the resource pool. The resource pool selected has an associated beamforming direction that matches the transmission direction. For instance, in FIG. 5, the vehicle 54 determines that the vehicle 54 wants to transmit signals towards the front of the vehicle, i.e., the determined direction is front. Furthermore, the vehicle 14, based on the resource pool configuration 500, knows that four resource pools 510-525 are provided and the resource pool 510 is associated with transmitting towards front. Thus, the vehicle 54 may select the resource pool 510 as a candidate resource pool for transmission of the signal from the four resource pools. Similarly, when the vehicle 54 needs to transmit signals to other vehicles behind the vehicle 54, the vehicle 54 may determine that the transmission direction of the signal is rear of the vehicle 54. Based on the configuration 500, the vehicle 54 may select the resource 515 as a candidate resource pool for transmission of the signal.

In another example, if a vehicle wants to transmit signals to vehicles at a specific geographical direction, such as the vehicle 74 in FIG. 7 wants to transmit signals to vehicles at the west side of the vehicle 74, the vehicle 74 may determine that the transmission direction is west. Further combined with the configuration 702, the vehicle 74 may determine that the resource pool 710 among the four resource pools 710-725 is associated with the west. Then the vehicle 74 may select the resource pool 710 as a candidate resource pool for transmission of the signal. Similarly, if the vehicle 74 needs to transmit signals to another direction such as north as illustrated in FIG. 9, the vehicle 74 may determine the transmission direction is north. Taking the configuration 702 into consideration, the vehicle 74 may find that the resource pool 720 is associated with north. The vehicle 74 may then select the resource 720 as a candidate resource pool for transmission of the signal accordingly.

In operation 1050, the UE selects a resource from the determined resource pool. The resources may be selected for one or multiple signal transmissions.

The UE may select one or more directions in accordance with the spatial constraint configuration as shown in Table 3 above. The UE may select/determine one or more beams in accordance with spatial constraint configuration.

The UE may use a resource from the determined resource pool for transmission of the signal. If a resource pool is associated with an attribute such as a location, a type of service, and so on, the UE may need to obtain values of the attributes from entities such as a positioning system, a higher layer, and so on, in order to specify which resources are available to it. If the resources available in a resource pool are larger than the resources needed for transmitting a message, the UE may select, randomly or through a prior signaling, resources from the resource pool. The resource selection may be random or follow rules determined by the configuration or predetermined by the standard. The selected resources may or may not be contiguous in time or frequency, but may follow a pattern known to other UEs.

It is noted that although selection of resources from a resource pool may be random, it may be assisted by sensing information. For example, if a UE detects, through an antenna, that a transmission is in progress, it may refrain from transmission on resources that can collide with the ongoing transmission. For example, consider a UE that intends to make a discovery signal transmission in a resource pool through its front antenna. If the UE senses through its rear antenna that another UE is transmitting signals on resources of that resource pool, it can refrain from transmission on resources that will collide with the rest of the ongoing or future transmissions of the another UE. In this case, if the UE has already made a selection overlapping with those resources, it may refrain from transmission or, alternatively, it may select other resources that avoid a collision.

In operation 1060, the UE sends a signal to another UE in the transmission direction in the resource selected.

For example, the UE may send a discovery signal to another UE in a sidelink discovery procedure. The UE sending the discovery signal may be referred to as a discovered UE. A discovery signal may be a sequence-type signal, such as a reference signal, a synchronization signal, or a preamble. The discovery signal may, instead, be a message-type signal, such as a packet of data or payload in a broadcast channel. Alternatively, the discovery signal may be a combination of a sequence-type signal and a message-type signal, such as a data transmission containing reference signals or a synchronization signal block comprising synchronization signals and a broadcast message.

Information may be carried in the sequence, in the message, or in a combination thereof. The information carried by a discovery signal transmitted by a UE may include any or all of the following: an identity parameter of the discovery signal such as a sequence number; information related to a type of the discovery signal; an identity parameter of the UE, or a group of UEs, or a connection, and so forth; information related to a service or a type of connection that the UE is offering or requesting; information related to a minimum signal quality for initiating a sidelink connection; information related to the environment such as the interference being detected by the UE, channel conditions, number of current sidelink connections, and so forth; information related to resources used for transmission of the discovery signal, e.g., a spatial resource information such as a beam index; information related to other discovery signals from the UE such as information of any other replicas of the discovery signal; information related to resources allocated for transmission of a discovery report by another UE that may detect the discovery signal; other information for establishing, updating, or recovering a sidelink. A discovery report may be referred to, e.g., by a standard, as a discovery response or as other terms.

The size of a discovery signal may be fixed or may be variable based on what fields and what values are included in the message.

The modulation and coding scheme (MCS) to transmit a discovery signal may be fixed, e.g., by the standard, or may be variable. In the latter case, selection of an MCS from a set of possible MCSs may be up to the UE based on, for example, an interference it is detecting. Alternatively, an MCS for transmission of discovery signals may be selected and communicated by the network, for example, as a part of a resource pool configuration.

It is noted that depending on whether a discovery signal contains a variable number of information bits and whether the UE uses a variable MCS for transmitting a discovery signal, different discovery signals may need a variable amount of resources.

FIG. n illustrates a flow chart of a reception method noo between UEs in an embodiment of the present disclosure. In this embodiment, a reception of signals such as a discovery signal in a sidelink discovery is described hereinafter. The method noo may be indicative of operations performed by a UE, such as one of the V-UE 13-17, or 73-77.

In operation 1110, a UE obtains a resource pool configuration.

The resource pool configuration may indicate at least one resource pool. The resource pool may include at least one of time resources, frequency resources, or code resources. For example, the resource pool configuration may indicate four resource pools as illustrated in FIG. 3A or FIG. 4.

In operation 1120, the UE obtains a spatial constraint configuration for reception of a signal.

The UE obtains spatial constraints as explained in the aforementioned descriptions and examples. The spatial constraints may be determined for reception in which case they can be used directly.

The spatial constraint configuration may specify directions for reception that are associated with the resource pools specified by the resource pool configuration. Alternatively, the spatial constraint configuration may specify directions for transmission that are associated with the resource pools, and the UE determines directions for reception based on the directions for transmission (i.e., the dual of the spatial constraint). For example, the dual of transmission towards the front is reception from the rear.

In operation 1130, the UE determines a direction of signals that the UE wants to receive from, i.e., the reception direction.

Similar to the operation 1030, the UE may determine the reception direction according to the UE orientation. Alternatively, the UE may determine the reception direction according to the graphical direction.

The UE may select a reception direction from a set of directions as described with respect to operation 1030.

In operation 1140, the UE determines a resource pool based on the determined direction and the spatial constraint configuration.

The operations 1110 to 1140 are similar to the operations 1010 to 1040.

In operation 1150, the UE search signals in the selected resource pool in the determined reception direction.

In an example, if the UE wants to detect signals such as discovery signals from other UEs in the front, it needs to listen to resources associated with transmit beamforming towards the rear through receive beams directed towards the front. Similarly, if the UE wants to detect signals such as discovery signals from other UEs in the rear, it should listen to resources associated with transmit beamforming towards the front through receive beams directed towards the rear.

According to the above embodiments of the present disclosure, UEs configured with the same resource pool configuration and spatial constraint configuration have the knowledge of beamforming directions for communication. Thus, the UEs are able to reduce the set of directions they send and search for messages such as discovery messages. Consequently, beam search overhead could be reduced dramatically compared to an exhaustive beam search approach. Moreover, UEs receiving signals (e.g., detecting discovery signals) may select a resource pool directly in accordance with the resource configuration and the spatial constraint configuration. As a result, signaling overhead for the UEs may also be reduced. In addition, battery may be saved for the UEs since they do not need to monitor all of the resource pools.

In two-way communications (transmitting by two UEs to each other) between a pair of UEs (i.e., the two UE), when a discovered UE sends a discovery signal to a second UE, the second UE receives the discovery signals and may sends a discovery report (which may be called a connection request, etc.) to the discovered UE. The second UE is also referred to as a discovering UE.

In some embodiments, a discovering UE may send a discovery report to inform the discovered UE and possibly request to establish a sidelink. Further exchanging of messages may follow to complete the process of establishing the sidelink. This process is referred to as a handshaking in this disclosure.

In some embodiments, a discovering UE may send a discovery report to update information for a currently established sidelink or to recover a previously established sidelink. Such a discovery report may be a step of a handshaking process.

The information carried by a discovery report transmitted by a first UE in association with a discovery signal received from a second UE may include any or all of the following: an identity parameter of the discovery report such as a sequence number; an identity parameter of the discovery signal such as a sequence number; information related to a type of the discovery report; an identity parameter of the first UE, or a group of UEs, or a connection, and so forth; an identity parameter of the second UE, or an identity otherwise obtained from the received discovery signal; information related to a service or a type of connection that the first UE is offering or requesting; information related to a signal quality associated with the discovery signal; information related to the environment such as the interference being detected by the first UE, channel conditions, number of current sidelink connections, and so forth; information related to resources used for transmission of the discovery report, e.g., spatial resource information such as a beam index; information related to other discovery reports from the first UE such as information of any other replicas of the discovery report; information on whether and how the first UE is requesting to establish, update, or recover a sidelink; and other information for establishing, updating, or recovering a sidelink.

In the two-way communications between a pair of UEs that employ beamforming (e.g., analog beamforming), resources used for a first communication from a discovered UE to a discovering UE and resources used for a second communication from the discovering UE to the discovered UE may be associated. The association can help reduce the resources and spatial directions that the pair of UEs need to monitor by using the information that is obtained from the first communication for the second communication. This is especially beneficial and practical when the two communications are associated, e.g., the second communication is a discovery report, a channel state information (CSI) report, or an acknowledgement or a negative acknowledgement (ACK/NACK), in association with the first communication.

In the embodiments of the present disclosure, descriptions put an emphasis on the example of discovery signals and discovery reports for establishing a sidelink, but the same principles can be applied to other cases of two-way communication including unicast communications and gro upcast communications between any pair of UEs.

During a discovery process, a UE may transmit a discovery report following detection of a discovery signal from another UE. As mentioned above, if beamforming is employed, an association between resources for transmitting a discovery signal and resources allocated for an associated discovery report can be beneficial.

FIG. t2 illustrates a diagram t200 of a resource association in an embodiment of the present disclosure. The resources in two-way communications may be associated. In this example, discovery resources in discovery resource pools (DRPs), such as DRPr, DRP2 and DRP3, are associated with report resource pools (RRPs) such as RRPr, RRP2 and RRP3, respectively. With the association of DRPs with respective RRPs, a UE receiving a discovery signal that is sent in a DRP may determine a RRP associated with the DRP for feeding back a discovery report. For example, if a UE detects a discovery signal in DRP2, it uses RRP2 for transmitting a discovery report. Since beamforming is employed for transmission and/or reception of discovery signals, corresponding beams formed towards directions associated with the DRPs and RRPs may be applied for reception and/or transmission of the discovery report.

FIG. 13 illustrates a diagram 1300 showing an embodiment resource association. FIG. 13 shows an alternative for mapping from discovery resources (DRPs) to report resources (RRPs) in an embodiment of the present disclosure. Different from the example as shown in FIG. 12 in which each DRP is mapped to or associated with an RRP, in the example as shown in FIG. 13, each subset of a DRP is mapped to a subset of an RRP. For example, a subset DPR lA and a subset DRP lB in DRPi are mapped to a subset of RRP lA and a subset RRP lB in RRPi, respectively. Note that reporting resources are also configured in pools because there may be multiple UEs intending to transmit reports and, defining pools may reduce the probability of collision.

Similarly, subsets DRP 2A and 2B of DRP2 are mapped to subsets RRP 2A and 2B of RRP2, respectively. Subsets DRP 3A and 3B of DRP3 are mapped to subsets RRP 3A and 3B of RRP3, respectively. As an example, when a UE receives a discovery signal sent in DRP lB, the UE will transmit a discovery report in response to receipt of the discovery signal in RRP rB mapped to (or associated with) the DRP rB.

It is noted that despite showing a one-to-one correspondence between resources or resource pools in the above examples in the two-way communications, other options are not precluded. For example, one DRP may be associated with multiple RRPs, or multiple DRPs may be associated with one RRP.

In a sidelink discovery procedure, a discovering UE may perform a handshaking directly with the discovered UE, through a serving network, through another UE such as a head of a cluster of UEs, or a combination thereof. Resources allocated for sending a discovery report and possibly other steps of a handshaking procedure may be associated with a discovery signal through configurations (or pre-configuration), through the payload of the discovery signal itself, or a combination thereof. Similarly to the resource pool configured for sending discovery signals, resources for a discovery report and possibly other steps of a handshaking may be location-based or proximity-based and may comprise similar types of resource allocation parameters used for a resource pool for discovery. Indeed, resources allocated for transmitting a discovery report may also be selected from resource pools that may or may not overlap with resource pools allocated to transmission of discovery signals by the discovering UE. For example, in the case that the two resource pools (for transmitting discovery signals and for transmitting discovery reports) are identical, a UE may arbitrarily select resources from a resource pool for transmitting its own discovery signals and transmitting discovery reports in response to detection of discovery signals from other UEs.

In some examples, a 3-way or 4-way handshaking may be performed for establishing a sidelink connection. In the 4-way handshaking, information is exchanged between two UEs through a discovery signal and a discovery report. For example, a discovered UE sends a discovery signal to a discovering UE, and the discovering UE transmits a discovery report to the discovered UE. Then the discovered UE sends a connection request to the discovering UE, and the discovering UE sends a connection response to the discovered UE to establish the sidelink connection. In the 3-way handshaking, when the discovered UE receives the discovery report, the discovered UE sends a connection response to the discovering UE to establish the sidelink connection. Namely, the discovery report may partially act as a connection request. Therefore, a connection response is sufficient to establish a sidelink.

FIG. 44 illustrates a flowchart of a method 4400 for sidelink discovery between UEs in an embodiment of the present disclosure. In this embodiment, transmitting discovery signals with resource association are described.

In operation t4 o, a UE obtains a resource pool configuration for transmitting discovery signals.

The resource pool configuration specifies one or more DRPs for the discovery signals.

In operation 4420, the UE obtains a resource pool configuration for transmitting report signals, namely, a configuration for one or more RRPs for transmitting discovery reports. The UE may also obtain a resource association between the DRP(s) and the RRP (s), such as the resource association shown in FIG. 42 or FIG. 43. In operation 1430, the UE obtains a spatial constraint configuration for transmission of the discovery signals.

In operation 1440, the UE determines a transmission direction for a discovery signal which the UE wants to transmit.

In operation 1450, the UE determines a resource pool from the DRP(s) based on the transmission direction determined, the spatial constraint configuration and the resource pool configuration for the discovery signals.

In operation 1460, the UE selects a resource from the determined resource pool for the discovery signals, and selects a transmit beam in accordance with the transmission direction. Multiple beams could be selected if necessary according to the spatial constraint configuration.

In operation 1470, the UE transmits the discovery signal on the selected resource while applying the transmit beam in the transmission direction.

Descriptions and considerations in operations 1410 to 1470 are similar to the operations 1010 to 1060 in the example of FIG. 10.

In operation 1480, the UE selects receive beam(s) corresponding to the transmit beam(s).

In operation 1490, the UE searches for report signals (discovery reports) on the RRP(s) associated with the DRP(s) while applying the receive beam(s).

FIG. 45 illustrates a diagram of an embodiment method 4500 for sidelink discovery. FIG. 45 illustrates a diagram of a sidelink discovery method between UEs in an embodiment of the present disclosure. In this embodiment, receiving discovery signals and transmitting discovery reports with resource association are described.

In operation rsro, a UE obtains a resource pool configuration for transmitting discovery signals, i.e., a configuration for one or more DRP.

In operation 4520, the UE obtains a resource pool configuration for report signals, namely, a configuration for one or more RRPs for transmitting the report signals.

The UE may also obtain a resource association between the DRP(s) and the RRP(s), such as the resource association shown in FIG. t2 or FIG. 43. In operation 1530, the UE obtains a spatial constraint configuration for reception of a discovery signal.

In operation 1540, the UE determines a direction of signals that the UE wants to receive from.

In operation 1550, the UE determines a resource pool based on the determined direction and the spatial constrain configuration.

The UE may further select a receive beam in accordance with the spatial constraint configuration. Multiple beams could be selected if necessary according to the spatial constraint configuration.

In operation 1560, the UE searches signals in the selected resource pool in the determined reception direction(s). The UE may then detect a discovery signal received in the receive beam.

Descriptions and considerations in operations 1510 to 1560 are similar to the operations 1110 to 1150 in the example of FIG. 11.

In operation 1570, the UE selects resources from the RRP(s) and selects a transmit beam corresponding to the receive beam.

In operation 1570, the UE transmits report signals on the selected resources while applying the transmit beams.

Beam correspondence for transmitting a discovery report may follow an assumption that the plurality of the wireless channel and the hardware used for transmission and reception of signals are substantially reciprocal.

The UE detecting a discovery signal may increase the transmission power for each retransmission of a discovery report in order to increase the probability that it is received by the discovered UE.

Diversity methods such as repetition methods can be employed to increase the probability that the discovered UE receives a discovery report. In the repetition methods, multiple replicas of a discovery report is transmitted by using different resources in time, frequency, code, space, or a combination thereof. In particular, in order to provide spatial diversity, the discovering UE may use different analog beams for transmission of multiple replicas of a discovery signal. By applying these methods, some issues with the reciprocity assumption could be resolved, such as the channel may not be (fully) reciprocal due to, e.g., hardware imperfections; the channel may be reciprocal, but interference may introduce asymmetries in the signal quality between the two directions, hence making it less probable for a discovery report to be received in the allocated resources.

In some examples, in order to provide the possibility of spatial diversity, a discovery signal may be associated with more than one resource pool for transmitting discovery reports. The association may be communicated to the UE through a configuration or through the content of the discovery signal.

In some embodiments, a discovery signal may have an additional role of a discovery report, e.g., by including information for newly discovered UEs. For instance, a discovery signal sent from a discovering UE may include information showing that another discovery signal sent from a discovered UE was detected. Then, this information may be used by the two UEs to establish, update, or recover a link.

As mentioned, a configuration of a discovery resource pool or a discovery signal itself may contain information of which resources can be used for transmission of a discovery report. The resources allocated for a discovery report may be sufficient for one or multiple discovery reports.

In an embodiment, the resources are sufficient for transmitting only one discovery report and there is a possibility that multiple discovering UEs attempt to transmit discovery reports on the same resources, which may cause a collision between the discovery reports. In this case, a discovering UE that does not receive a handshaking message after transmitting a discovery report may perform a random backoff before retransmitting the discovery report in order to reduce the probability of further collisions.

In another embodiment, the resources are sufficient for multiple discovery reports. In this case, a discovering UE may use one or multiple of the following example methods for transmission of a discovery report. For example, the discovering UE may use random access, i.e., random selection of resources from the available resources. Alternatively, the discovering UE may use transmission diversity, i.e., transmitting more than one discovery report in response to detecting a discovery signal. The discovering UE may also use random backoff, i.e., delaying a retransmission of a discovery report in the case that a collision is detected.

When a UE transmits or receives discovery signals or discovery reports in resource pools as configured in previous examples, constraints may be applied for scheduling transmission or reception of other signals to the UE, which may or may not be performed simultaneously with transmission or reception a discovery signal or discovery report by the UE.

Variations may depend on whether the UE will use a discovery resource pool only to transmit discovery signals, or the UE also uses the discovery resource pool to search for discovery signals from other UEs. If the UE only wants to transmit a discovery signal on resources selected from a resource pool, the UE may be busy for a relatively short period of time, e.g., one or a few symbol durations. If the UE wants to receive discovery signals, it may be busy for the whole period of the resource pool, which may span a possibly extensive period of time such as a whole slot or subframe.

Variations may also be made based on whether or not analog beamforming is employed, which may depend on the frequency band. If only digital beamforming is employed, the UE may be able to transmit other signals simultaneously with transmitting a discovery signal, or it may be able to receive other signals simultaneously with listening to the discovery pool. Or if analog beamforming is employed, possibly in addition to digital beamforming in a hybrid manner, the UE may not be able to transmit or receive other signals to/from a particular direction simultaneously with transmitting or searching for discovery signals.

In addition, cases of transmission and reception are distinguished, as mentioned earlier, due to the half-duplex constraint. Different example cases are given as below.

In a case where a UE employs analog beamforming, the following may be considered. Analog beamforming limits the spatial directions that a UE can transmit to or receive from. Therefore, in order to avoid complications, it may be agreed to avoid scheduling of other communications during the periods that the UE intends to perform analog beamforming to transmit a discovery signal or listen to a discovery resource pool. However, if the UE is going to be busy for a short period of time such as a symbol to only transmit a discovery signal, it may be possible to schedule communications with the UE, while the interruption due to the discovery signal transmission can be treated as an erasure in the forward error correction (FEC) process.

A UE may not employ analog beamforming, and makes a short discovery signal transmission, and does not listen to a resource pool: In this case, the UE can transmit other signals simultaneously with the discovery signal without interruption. Similar to the previous case, reception of signals may also be possible while the interruption due to the discovery signal transmission can be treated as an erasure in the FEC process.

A UE may not employ analog beamforming, and makes a long discovery signal transmission. In this case, it may be only possible for the UE to perform transmissions of other signals simultaneously with transmission of the discovery signal. In the case that different UE antennas may perform different tasks at a time instant, this constraint may be applicable to each antenna of the UE rather than the whole UE.

A UE may not employ analog beamforming, and listens to a resource pool for discovery signals or reports. In this case, the UE may be able to only receive signals simultaneously with the resource pools it is listening to. In the case that different UE antennas may have to perform different tasks at a time instant, this constraint may be applicable to each antenna of the UE rather than the whole UE.

If any of the scheduling constraints as described above are applicable to a UE, other nodes that may transmit to the UE, expect a transmission from the UE, or schedule a transmission for the UE, may need to be informed of the constraints. Informing the other nodes may be performed implicitly or explicitly through signaling. An implicit way is when other nodes know which resource pools are selected by the UE. An explicit way may be that the UE informs other nodes of the scheduling constraints or the resource pools of its interest. For example, the UE may inform the network or other UEs on sidelinks that it will be busy during certain periods of time or that certain resource pools are of interest to the UE.

In an embodiment, resource pool selection for transmitting a discovery signal by a UE may not be communicated to other nodes, such as a base station or another UE. In this case, transmission of a discovery signal may occur simultaneously with reception of other signals by the UE. As a result, the reception of the other signals may be disrupted and the UE may not be able to decode the other signals. This issue can be handled using a hybrid automatic repeat request (HARQ) process where the UE first attempts to decode the signals through forward error correction (FEC) where the disruption is treated as erasure. If the decoding is not successful, the UE may then inform the transmitter(s) of the signals of an unsuccessful reception, e.g., through a non-acknowledgement (NACK) signaling, possibly requesting a retransmission.

Optionally, in order for the UE to be aware of the transmission and respond with a NACK, the UE may be able to receive control signaling without disruption by the discovery channel. Therefore, in some embodiments, it may be required for control and discovery channels or resources to be scheduled in a time-division multiplexing (TDM) manner rather than a frequency-division multiplexing (FDM) manner. Such a requirement may be imposed by a standard or a network.

In some embodiments, because such scheduling constraints may impact quality of service, a UE may be limited in the number or amount of resource pools it may listen to or transmit on during a certain interval. Such a limitation may be set by the standard, configured by the network, determined by the quality of service requirements of the current traffic, or by other methods.

FIG. i6 is a flowchart of a communication method 1600 of an embodiment in the present disclosure. This method 1600 shows an example for a UE with multiple antennas for transmission and reception of signals with spatial constraints.

In operation 1601, the UE obtains a resource pool configuration of at least one resource pool. In operation 1602, the UE obtains a spatial constraint configuration in association with the resource pool configuration. The spatial constraint configuration may specify a spatial constraint for each of the at least one resource pool.

In operation 1603, the UE may determine a set of antennas A = {A,, ..., A_n} that it may use for a communication or a discovery process.

Different variations are possible. This step is applicable when the set of available antennas A may vary from time to time depending on different factors such as scheduling constraints at a certain time, power constraints that may turn some of the antennas on or off, and so forth. In the illustration of FIG. 16, such cases are omitted for the sake of brevity.

In operation 1604, for each antenna A_j, the UE may decide whether A_j is to be used for transmission or reception of signals. This decision is needed when the half-duplex constraint is applied. The UE performs this step and any of the steps that follow in a loop over all A_j, j= 1, .. n, in the set of antennas A, although this loop is omitted in FIG. 16 for the sake of clarity.

During time intervals that one or more antennas in A are not scheduled for a particular communication such as a discovery process (referred to as spare antenna(s)), for example, front and rear antennas of a UE during the time intervals of resource pools 330 and 340 as illustrated in FIG. 3A, the spare antennas may still participate in the communication or discovery process in a best-effort manner. In another example, the spare antennas may be used to, or be scheduled to, communicate other signals such as control and data. Alternatively, the spare antennas may be turned off for power saving purposes.

If antenna A_j is to be used for transmission, in operations 1605 and 1606, the UE uses the antenna for transmission of discovery signals. The operations 1605 and 1606 may be similar to the operations 1050 an 1060.

If antenna A_j is to be used for reception, in operation 1607, the UE may determine the reception dual constraints based on the spatial constraint configuration. Then, in operations 1608 and 1609, the UE uses the antenna to search for discovery signals. The operations 1608 and 1609 may be similar to the operations of 1130 and 1150.

In embodiments of the present disclosure, a sidelink discovery at HF may be assisted in LF. Discovery at an HF band can be assisted by a connection at an LF band. In an embodiment, a first discovery process may be performed by UEs at LF or assisted by communications at LF. If it is desired to communicate at HF, the UEs may exchange information such as location or proximity information that assists with performing beamforming and establishing a link at HF. For example, handshaking/link-establishment messages at LF or messages that follow handshaking/link-establishment at LF may contain location information and/or other information assisting the UEs to perform beamforming or an initial beam acquisition, possibly in addition to timing of such an initial beam acquisition process, which will assist the UEs to find each other through proper beam pairs at HF. This may then be followed by a separate handshaking/link-establishment process at HF.

FIG. 17 is a flowchart of a communication method 1700 in an embodiment of the present disclosure.

In operation 1701, a first UE transmits and/or listens to receive discovery signals at an LF band from other UEs in its vicinity.

In operation 1702, having discovered a second UE, the first UE performs a handshaking/link-establishment process at the LF band.

In operation 1703, the two UEs communicate information on availability of an HF band for sidelink communications. This operation may be combined with the operation 1702 by including the HF availability information in messages communicated in operation t702.

In operation t704, the two UEs communicate, at the LF band, information on beam acquisition at the HF band available to both UEs. This information may contain location information, beam direction information, timing of transmission and reception of reference signals for beamforming, for example in order to avoid transmitting or receiving the reference signals by both UEs simultaneously, and so on. Similarly, this operation may be combined with the operation 1703 and/or the operation 1702 by including the information in previously communicated messages.

The two UEs may then proceed to communication at the HF band in operation 1705 by performing beam acquisition through transmitting and/or receiving beamformed reference signals, possibly followed by reporting beam information and/or channel state information (CSI). A beam information report may contain a beam index and beam quality associated with the beam, such as a reference signal receive power (RSRP). It is noted that although the reference signals may be communicated at the HF band, the reporting may be performed at the LF band for the sake of improved reliability. An alternative to beamformed reference signals is beamformed discovery signals. In that case, a beam report may be replaced by a discovery response, a connection request, or a similar message.

In operation 1706, the two UEs perform handshaking/link-establishment at the HF band. The two UEs may or may not need to perform a separate beam-establishment process at the HF band by using the beams acquired in operation 1705.

FIG. 18 is a flowchart of a communication method 1800 in another embodiment. The method 1800 may be indicative of operations by a communications device, such as a UE. As shown, at step 1802, the UE obtains a resource pool configuration, with the resource pool configuration specifying a plurality of resource pools, and each of the plurality of resource pools associated with a beamforming direction. At step r804, the UE selects a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and in accordance with a communication direction in which a signal is to be communicated by the UE. The communication direction is a direction in which a beam is to be formed for communication of the signal. At step r8o6, the UE communicates the signal in the communication direction using a first resource of the first resource pool. The UE may communicate the signal by transmitting the signal in a transmission direction or receiving the signal in a reception direction. The constrained beamforming methods proposed in the present disclosure can be applied to LF-assisted communication at HF. In the previous example, constrained beamforming can be applied to operations 1705 and 1706 while the signaling can be provided at LF in the operation 1704.

The embodiments described above had an emphasis on establishing a unicast link between two UEs. However, extensions are possible for establishing a multicast or groupcast link among multiple UEs. For example, once a groupcast link is established among a group of UEs, they can communicate beam acquisition information, e.g., in a round-robin arrangement, for transmission of reference signals by the UEs. The order of UEs in the round robin can be determined by a pseudo-random process, based on a UE ID such as an RNTI, based on their relative locations such as front UEs to rear UEs or vice versa, or by other methods.

In a first aspect, a method for transmitting a signal performed by a first user equipment using beamforming is provided. The first user equipment obtains a resource pool configuration. The resource pool configuration indicates multiple resource pools and each of the multiple resource pools is associated with a beamforming direction. The first user equipment may determine a transmission direction of a signal to be transmitted, and then the first user equipment may select a resource pool from the multiple resource pools in accordance with the transmission direction and the beamforming direction. The first user equipment further selects a resource from the selected resource pool and transmits the signal towards the determined transmission direction in the selected resource.

In a second aspect, a method for receiving a signal performed by a second user equipment using beamforming is provided. The second user equipment may receive a signal from other equipment. To achieve this, the second user equipment may obtain a resource pool configuration. The resource pool configuration indicates multiple resource pools and each of the multiple resource pools is associated with a beamforming direction. The second user equipment may determine a reception direction that the user equipment wants to receive the signal from. Then the second user equipment may select a resource pOOl from the multiple resource pools in accordance with the determined reception direction and the beamforming direction, and receives the signal towards the determined reception direction in the selected resource pool.

According to the embodiments of the above aspects, the user equipments may transmit or receive with reduced latency of communications between user equipments because, with the directional beamforming, the user equipments don’t need to make an exhaustive beam search. Moreover, the user equipment may transmit and/or receive signals in a resource pool selected based on the spatial constraint configuration towards a specific direction. Thus, the user equipment may improve the resource efficiency. In addition, the user equipment that receives the signal may select a resource pool directly in accordance with the spatial constraint configuration, it could reduce the signaling overhead for the user equipment that needs to receive the signal. The power may be saved since it does not need to monitor all of the resource pools.

In a first possible implementation of the method according to above aspects, the beamforming direction comprises a direction on a horizontal plane with respect to an orientation of the user equipment. Alternatively, the beamforming direction may comprise a direction on a horizontal plane with respect to a geographical direction. In a scenario that user equipments having a substantial moving direction, the beamforming direction may be determined according to the orientation of the user equipment, such as the front, rear, left, or right of the user equipment. For the user equipments with different moving directions, the beamforming direction may be determined according to the geographical direction, such as the north, south, west, or east.

In a second possible implementation of the method according to above aspects and implementation, the user equipment may determine a set of antennas, and further determine an available antenna from the set of antennas for transmitting or receiving the signal. The user equipment may use the available antenna to transmit or receive the signal in the selected resource through a beam directed towards the beamforming direction. For an antenna that is not selected, the user equipment may turn off it, power could be saved accordingly. In a third possible implementation of the method according to above aspects and implementations, the beamforming direction being indicated by a spatial constraint configuration. The resource pool configuration and the spatial constraint configuration being comprised in at least one of a radio resource control (RRC) message, a medium access control (MAC) message, or a physical layer message.

In a fourth possible implementation of the method according to above aspects and implementations, the signal comprises a discovery signal for establishing a sidelink. The first user equipment may receive a report response that is in response to the discovery signal from the second user equipment in a second resource pool. The selected resource pool and the second resource pool may be associated.

In a possible implementation of the method according to the first aspect, the first user equipment may receive a signal from other user equipments towards a second direction that is opposite to the selected transmission direction. Then the first user equipment may select a resource pool corresponding to the second direction in accordance with the resource pool configuration, and monitor the resource pool corresponding to the second direction to receive the signal. No additional configuration is needed to realize the reception of signals in this implementation, thus, signaling overhead could be reduced.

In a possible implementation of the method according to the second aspect, the second user equipment may transmit a signal toward a third direction that is opposite to the selected transmission direction. The second user equipment may select a resource pool corresponding to the third direction in accordance with the resource pool configuration, and select resources from the selected resource pool. The second user equipment further may transmit the signal in the selected resources. Similarly, no additional configuration is needed to realize the transmission of signals in this implementation. Thus, signaling overhead could be reduced.

In a third aspect, a user equipment is provided. The user equipment comprises a non-transitoiy memory storing instructions; and one or more processors in communication with the non-transitory memory, wherein the one or more processors execute the instructions to perform the method according to the first and second aspects and corresponding possible implementations.

In a fourth aspect, a non-transitory computer-readable media is provided. The non-transitory computer-readable media is configured to store computer instructions that when executed by one or more processors, cause the one or more processors to perform to the methods according to the first and second aspects and above possible implementations.

In a fifth aspect, a chipset system is provided. The chipset system includes at least one processor, used to implement the functionality of the above user equipments. The chipset system may further include a memory for storing program instructions and data. The chipset system may be comprised by chipsets, and may also be comprised by at least one of chipsets and other discrete device.

The following options for discovery may be considered for establishing a sidelink.

“Option o”: Discovery through the network: UEs connected to a network can be assisted by the network to discover each other. The discovery process may be initiated by the network or by a UE interested to establish a sidelink connection with another UE in its vicinity.

Option l: Discovery through safety messages or other communication messages: Safety messages are to be broadcast by UEs in V2X communications. It has been proposed previously that the safety messages be used for the purpose of discovering other UEs, i.e., when a first UE receives a safety message from a second UE, it automatically realizes that the second UE is in its vicinity and can establish a sidelink with the second UE for unicast or groupcast communications. There are multiple issues with this method. Firstly, this method overloads the role of safety messages and, therefore, limits and/or complicates the design of safety messaging and/or discovery signaling. Secondly, a UE broadcasting safety messages may not be necessarily interested in establishing a sidelink for unicast or groupcast or may not be interested in a specific service or otherwise a specific connection. In these cases, a significant amount of resources may be wasted on unsuccessful attempts to establish sidelinks. Thirdly, this method is useful specifically for V2X applications and may not be feasible for other D2D applications.

Option 2: Discovery through the use of a specific channel between devices: With this method, a set of resources (resource pools) is reserved for the UEs to transmit discovery messages, possibly on a dedicated channel (e.g., PSDCH or Physical Sidelink Discovery Channel)

LTE device-to-device (D2D) provides discovery resource pools for proximity services (ProSe). A discovery resource pool configuration contains a discovery period, a subframe offset, a subframe bitmap, number of repetitions in time, and parameters for allocation of physical resource blocks (PRBs) in frequency. Configurations are different between time-division duplexing (TDD) and frequency-division duplexing (FDD) modes.

One of the LTE D2D techniques is discovery, which consists in the ability to discover neighboring UEs. Discovery can be either eNB-assisted or open discovery. With eNB-assisted discovery, one UE is directed to transmit a signal, e.g., a sounding reference signal (SRS), and another UE is required to listen and report the signal quality to the enhanced NodeB (eNB). The eNB can then, based on this reported signal quality, decide if proximity services (ProSe) can be enabled for the two UEs. With open discovery, any UE can transmit a“beacon” signal to advertise its presence to other UEs. Note that this process can possibly involve idle UEs.

For D2D communications, it is also generally assumed that D2D occurs on the uplink (UL) portion of the bandwidth since the interference would be less prejudicial to cellular UEs on the UL. On the UL, a transmitting D2D UE may interfere with an eNB. Consequently, as long as the D2D UE is at a reasonable distance from the eNB, the interference created by the D2D UE may not have significant impact. Conversely, on the downlink (DL), D2D interference affects neighboring UEs and, potentially, their ability to receive synchronization channels and control channels may be affected and can result in significantly higher impact than if the D2D UE were transmitting only on the UL frequencies. When D2D communication takes place on the UL frequencies, it is reasonable to assume that the D2D discovery occurs on the UL frequencies as well.

For open discovery, a given number of subframes, e.g., 1%, are reserved for discovery. During these subframes, there usually is no cellular communication multiplexed simultaneously. Only UE discovery signals are transmitted.

The subframe devoted for discovery is composed of several discovery resources (DR). A DR comprises a set of resource elements (REs) within the subframe. For instance, a DR could be an entire physical resource block (PRB) pair.

One of the features of the fifth-generation (5G) new radio access (NR) technology is the possibility of operating in a wider range of frequencies compared to earlier cellular wireless standards such as the long-term evolution (LTE). Transmissions at HF/FR2 suffer higher path-loss than LF/FRt and motivate the use of directional antennas, for example, through radio frequency (RF) analog beamforming (ABF) for transmission and/or reception of radio signals. When multiple arrays and RF chains are employed, beamforming can be applied at both analog and digital domains, providing the possibility of “hybrid beamforming” (HBF). Note that the concepts are applicable to both transmission and reception.

Analog and hybrid beamforming reduce complexity of hardware implementation and channel state information (CSI) acquisition compared to a fully digital beamforming (DBF) solution at the cost of limitations that they introduce. A well-known limitation in practice is the spatial constraints imposed by analog beamforming, i.e., analog beams limit the maximum number of“directions” to/from which signals can be received to the number of RF chains or the number of antenna panels with distinct phase-shifter controllers.

Beam management is as follows. Configurations are usually produced and transmitted by a network controller. Beamformed reference signals may be transmitted by a network entity for downlink beam training and/or by a UE for uplink beam training. If beam information is reported, the report may be produced by performing measurements on the beamformed reference signals and transmitted by a UE for downlink beam training and/or by a network entity for uplink beam training. If the beam quality may be improved by refining beams, e.g., refining beam directions and/or widths, more beamformed reference signals may be transmitted and may be possibly followed by a reporting.

If beams are suitable for communications, they may be indicated by a network controller for communications that follow. The motivation for beam indication is that, during the beam training when beamformed reference signals are transmitted, the receiver may also perform beamforming and obtain receive beams that allow the receiver to receive the beamformed reference signals with the highest quality. Therefore, information of transmit beams applied for a certain communication allows the receiver to apply corresponding receive beams. Beams obtained at a particular time instance may experience quality degradation over time or may expire. For this reason, the quality of beams may be continuously monitored and beam information may be updated by refining old beams or obtaining new beams.

In the NR specification, CSI acquisition and beam management (BM) share a common framework referred to as the CSI framework. Indeed, a majority of BM-related content in the NR specification reuses CSI acquisition terminology and processes. For example, a beam report may be essentially a CSI report where the report quantity includes an index to one or multiple reference signals and the quality of the indexed reference signal(s). In this example, since the reference signal is transmitted through a beam, the reported index generally indicates the beam.

A brief description of the framework is as follows. The network configures a CSI acquisition (and/or BM) process such as CSI resource settings and CSI reporting settings. Each resource setting may comprise one or more resource sets, each containing one or multiple resources. The resources may comprise reference signals such as CSI reference signals (CSI-RS) and/or synchronization signal blocks (SSBs), with each SSB containing synchronization signals and an associated physical broadcast channel (PBCH). Each reporting setting may indicate the quantity to be reported. Typical quantities for beam reporting are reference signal indices, which may comprise CSI-RS resources indices (CRIs) and/or SSB resource indices (SSBRIs), and their qualities in the form of, e.g., layer-t reference signal receive power (Lt-RSRP). Typical quantities for CSI report may be a channel quality indicator (CQI), a precoding matrix indicator (PMI), and a rank indicator (RI). A reporting setting may also include links to resources, which may essentially indicate which resources should be used to produce which reports.

Following the configurations, reference signals may be transmitted, measured, and reported. Particularly, in downlink, downlink reference signals are transmitted by network entities such as TRPs, the reference signals are measured by a UE, and reports are produced and transmitted by the UE. The beamforming information obtained through these procedures, also known as the“spatial” information, may then be used along other CSI by the network and/ or the UE for communications that follow.

Indication of spatial information corresponding to analog beamforming is enabled in the NR specification through introduction of a new type of quasi-collocation (QCL) called QCL Type D or spatial QCL that helps infer (spatial) beamforming information for reception of a signal.

FIG. 19 illustrates a diagram of a UE 1900 in an embodiment of the present disclosure. The UE 1900 comprises any one of UEs 13-14 as described above. As shown in FIG. 19, the UE 1900 includes at least one processor 1910, at least one transmitter (Tx) 1920, at least one receiver (Rx) 1930, one or more antennas 1940, and at least one memory 1950. The processor 1910 implements various processing operations of the UEs 13-17 and UEs or vehicles as described in above examples and embodiments, such as signal coding, signal processing, positioning determination, determining transmission direction, selecting resource, or any other functionality. The processor 1910 can also support the methods and teachings described in more details described in embodiments of the present disclosure. Each processor 1910 includes any suitable processing or computing device configured to perform one or more operations. Each processor 1910 could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit. Each transmitter 1920 includes any suitable circuitry for generating signals for wireless transmission to one or more UEs or other devices. Each receiver 1930 includes any suitable circuitry for processing signals received wirelessly from one or more UEs or other devices. Although shown as separate components, the at least one transmitter 1920 and the at least one receiver 1930 could be combined into a transceiver. Each antenna 1940 includes any suitable structure for transmitting and/or receiving signals. While a common antenna 1940 is shown here as being coupled to both the transmitter 1920 and the receiver 1930, one or more antennas 1940 could be coupled to the at least one transmitter 1920, and one or more separate antennas 1940 could be coupled to the at least one receiver 1930.

Each memory 1950 includes any suitable volatile and/or non-volatile storage and retrieval device(s). The memory 1950 is non-transitory memory storage, in one embodiment. The memory 1950 stores instructions and signal used, generated, or collected by the UEs 13-17. For example, the memory 1950 could store software or firmware instructions executed by the processor 1910 to implement the above embodiments. Any suitable type of memory may be used, such as RAM, ROM, hard disk, optical disc, SIM card, memory stick, SD memory card, or the like.

The present disclosure provides another embodiment with respect to a user equipment, which comprises a non-transitory memory storing instructions, and one or more processors in communication with the non-transitory memory, where the one or more processors execute the instructions to perform the embodiments as described above.

An embodiment of a non-transitory computer-readable media is provided in the present disclosure. The non-transitory computer-readable media is configured to store computer instructions that when executed by one or more processors, cause the one or more processors to perform to the embodiments as described above.

An embodiment of a chipset system is provided in the present disclosure. The chipset system includes at least one processor, used to implement the functionality of the above user equipment. The chipset system may further include a memory for storing program instructions and data. The chipset system may be comprised by chipsets, and may also be comprised by at least one of chipsets and other discrete device.

Embodiments of the present disclosure may be implemented as computer-implemented methods. The embodiments may be performed by a processing system. FIG. 20 illustrates a block diagram of an embodiment processing system 2000 for performing methods described herein, which may be installed in a host device. As shown, the processing system 2000 includes a processor 2004, a memory 2006, and interfaces 2010-2014, which may (or may not) be arranged as shown in FIG. 20. The processor 2004 may be any component or collection of components adapted to perform computations and/or other processing related tasks, and the memory 2006 may be any component or collection of components adapted to store programming and/or instructions for execution by the processor 2004. In an embodiment, the memory 2006 includes a non-transitory computer readable medium. The interfaces 2010, 2012, 2014 may be any component or collection of components that allow the processing system 2000 to communicate with other devices/components and/or a user. For example, one or more of the interfaces 2010, 2012, 2014 may be adapted to communicate data, control, or management messages from the processor 2004 to applications installed on the host device and/or a remote device. As another example, one or more of the interfaces 2010, 2012, 2014 may be adapted to allow a user or user device (e.g., personal computer (PC), etc.) to interact/communicate with the processing system 2000. The processing system 2000 may include additional components not depicted in FIG. 20, such as long term storage (e.g., non-volatile memory, etc.).

In some embodiments, the processing system 2000 is included in a network device that is accessing, or part otherwise of, a telecommunications network. In one example, the processing system 2000 is in a network-side device in a wireless or wireline telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an applications server, or any other device in the telecommunications network. In other embodiments, the processing system 2000 is in a user-side device accessing a wireless or wireline telecommunications network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet, a wearable communications device (e.g., a smartwatch, etc.), or any other device adapted to access a telecommunications network.

In some embodiments, one or more of the interfaces 2010, 2012, 2014 connects the processing system 2000 to a transceiver adapted to transmit and receive signaling over the telecommunications network.

It should be appreciated that one or more operations of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other operations may be performed by other units/modules, such as an obtaining unit/module, a selecting unit/module, a communicating unit/module, a monitoring unit/module, an associating unit/module, a determining unit/module, or a beamforming unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

Although the description has been described in detail, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Moreover, the scope of the disclosure is not intended to be limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from this disclosure that processes, machines, manufacture, compositions of matter, means, methods, or operations, presently existing or later to be developed, may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or operations. The terminology used in the description of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used in the description of the present disclosed and the appended claims, the singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. In the embodiments of the present disclosure,“at least one” means one or multiple. The term“multiple” means two or more than two. The term“and/or” describes a relationship between the associated items. The term “and/or” may represent three relationships. For example, “A and/or B” may represent situations of A independently, A and B concurrently, and B independently. Where A and B could be singular or plural. The symbol“/” usually means“or” of the associated items. The expression“at least one item of’ or similar expressions may mean any combination of the items, including any combination of singular item, or the plural of items. For instance, at least one of a, b, or c may comprise a, b, c, a plus b, a plus c, b plus c, or a plus b plus c, where a, b, c may be singular, or may be plural.

While this disclosure has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the disclosure, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.

Claims

WHAT IS CLAIMED IS:

1. A method comprising:

obtaining, by a user equipment (UE), a resource pool configuration, with the resource pool configuration specifying a plurality of resource pools, each pool of the plurality of resource pools being associated with a beamforming direction;

selecting, by the UE, a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and in accordance with a communication direction, the communication direction being a direction in which a beam is to be formed for communication of the signal; and

communicating, by the UE, the signal in the communication direction using a first resource of the first resource pool.

2. The method according to claim l, wherein communicating the signal comprises: transmitting, by the UE, the signal in the communication direction, wherein the communication direction is a transmission direction in which the signal is to be transmitted.

3. The method according to claim 2, wherein transmitting the signal comprises: transmitting, by the UE, the signal using a first beam that is beamformed according to the first beamforming direction associated with the first resource pool.

4. The method according to any one of claims 1-3, further comprising:

transmitting, by the UE, the signal in a deviated direction that is deviated from the first beamforming direction according to a predefined deviation.

5. The method according to any one of claims 2-4, further comprising:

monitoring, by the UE in an opposite direction that is opposite to the first beamforming direction, the first resource pool for receiving a second signal.

6. The method according to any one of claims 2-5, further comprising:

receiving, by the UE, a response signal in a second resource in response to transmitting the signal, wherein the signal comprises a discovery signal.

7. The method according to claim 1, wherein communicating the signal comprises: receiving, by the UE, the signal in the communication direction, wherein the communication direction is a reception direction in which the signal is to be received.

8. The method according to claim 7, wherein receiving the signal comprises:

receiving, by the UE, the signal using a first beam that is directed in the first beamforming direction.

9. The method according to any one of claims 7-8, further comprising:

transmitting, by the UE in an opposite direction that is opposite to the reception direction, a second signal using a resource of the first resource pool. to. The method according to any one of claims 7-9, further comprising:

transmitting, by the UE, a response signal in a second resource in response to receipt of the signal, wherein the signal comprises a discovery signal.

11. The method according to claim 6 or to, wherein the second resource is associated with the first resource.

12. The method according to claim 11, further comprising:

obtaining, by the UE, an association between the first resource and the second resource.

13. The method according to claim 6 or to, wherein the first resource pool is associated with a second resource pool comprising the second resource.

14. The method according to claim 13, further comprising:

obtaining, by the UE, an association between the first resource pool and the second resource pool.

15. The method according to claim 12 or 14, further comprising:

determining, by the UE for communicating the response signal, the second resource according to the association.

16. The method according to any one of claims 1-15, wherein the beamforming direction comprises a direction with respect to an orientation of the UE.

17. The method according to any one of claims 1-15, wherein the beamforming direction comprises a direction with respect to a geographical direction.

18. The method according to any one of claims 1-17, wherein the resource pool configuration is obtained in a radio resource control (RRC) message, a medium access control (MAC) message, or a physical layer message.

19. The method according to any one of claims 1-18, wherein the beamforming direction is specified by a spatial constraint configuration.

20. The method according to claim 19, wherein the spatial constraint configuration and the resource pool configuration are obtained by the UE in a same message or different messages.

21. The method according to claim 19, wherein the spatial constraint configuration further specifies a maximum number of transmissions performable using one of the plurality of resource pools.

22. An apparatus comprising:

a non-transitory memory storage comprising instructions; and

one or more processors in communication with the memory storage, wherein the one or more processors execute the instructions to:

obtain a resource pool configuration, with the resource pool configuration specifying a plurality of resource pools, each pool of the plurality of resource pools being associated with a beamforming direction;

select a first resource pool from the plurality of resource pools in accordance with a first beamforming direction associated with the first resource pool, and in accordance with a communication direction, the communication direction being a direction in which a beam is to be formed for communication of the signal; and communicate the signal in the communication direction using a first resource of the first resource pool.

23. The apparatus according to claim 22, wherein communicating the signal comprises:

transmitting the signal in the communication direction, wherein the

communication direction is a transmission direction in which the signal is to be transmitted.

24. The apparatus according to claim 23, wherein transmitting the signal comprises: transmitting the signal using a first beam that is beamformed according to the first beamforming direction associated with the first resource pool.

25. The apparatus according to any one of claims 22-24, wherein the one or more processors execute the instructions to further:

transmit the signal in a deviated direction that is deviated from the first beamforming direction according to a predefined deviation.

26. The apparatus according to any one of claims 23-25, wherein the one or more processors execute the instructions to further:

monitor, in an opposite direction that is opposite to the first beamforming direction, the first resource pool for receiving a second signal from another apparatus.

27. The apparatus according to any one of claims 23-26, wherein the one or more processors execute the instructions to further:

receiving a response signal in a second resource in response to transmitting the signal, wherein the signal comprises a discovery signal.

28. The apparatus according to claim 22, wherein communicating the signal comprises:

receiving the signal in the communication direction, wherein the communication direction is a reception direction in which the signal is to be received.

29. The apparatus according to claim 28, wherein receiving the signal comprises: receiving the signal using a first beam that is directed in the first beamforming direction. 30. The apparatus according to any one of claims 28-29, wherein the one or more processors execute the instructions to further:

transmit, in an opposite direction that is opposite to the reception direction, a second signal using a resource of the first resource pool.

31. The apparatus according to any one of claims 28-30, wherein the one or more processors execute the instructions to further:

transmit a response signal in a second resource in response to receipt of the signal, wherein the signal comprises a discovery signal.

32. The apparatus according to claim 27 or 31, wherein the second resource is associated with the first resource.

33. The apparatus according to claim 32, wherein the one or more processors execute the instructions to further:

obtain an association between the first resource and the second resource.

34. The apparatus according to claim 27 or 31, wherein the first resource pool is associated with a second resource pool comprising the second resource.

35. The apparatus according to claim 34, wherein the one or more processors execute the instructions to further:

obtain an association between the first resource pool and the second resource pool.

36. The apparatus according to claim 33 or 35, wherein the one or more processors execute the instructions to further:

determine the second resource according to the association for communicating the response signal.

37. The apparatus according to any one of claims 22-36, wherein the beamforming direction comprises a direction with respect to an orientation of the apparatus.

38. The apparatus according to any one of claims 22-36, wherein the beamforming direction comprises a direction with respect to a geographical direction.

39. The apparatus according to any one of claims 22-38, wherein the resource pool configuration is obtained in a radio resource control (RRC) message, a medium access control (MAC) message, or a physical layer message.

40. The apparatus according to any one of claims 22-39, wherein the beamforming direction is specified by a spatial constraint configuration.

41. The apparatus according to claim 40, wherein the spatial constraint configuration and the resource pool configuration are obtained by the apparatus in a same message or different messages. 42. The apparatus according to claim 40, wherein the spatial constraint configuration further specifies a maximum number of transmissions performable using one of the plurality of resource pools.