Methods and systems for receive and transmit beam pairing in full duplex systems

Aspects of the present disclosure provide a manner of avoiding excessive latency and resource consumption due to exhaustive beam searching and pairing for finding an appropriate bi-directional beam pair combination with manageable mutual interference to enable point-to-point FD transmission. Aspects of the present disclosure also provide a solution for enabling multi-user transmission where one or all UEs are with FD capability and the cross-UE interference raised from FD transmission are measured and taken into account during multi-user pairing.

TECHNICAL FIELD

The present disclosure relates generally to wireless communications, and in particular embodiments, use of receive and transmit beam pairing in full duplex systems.

BACKGROUND

In some wireless communication systems, user equipments (UEs) wirelessly communicate with a base station to send data to the base station and/or receive data from the base station. A wireless communication from a UE to a base station is referred to as an uplink (UL) communication. A wireless communication from a base station to a UE is referred to as a downlink (DL) communication. A wireless communication from a first UE to a second UE is referred to as a sidelink (SL) communication or device-to-device (D2D) communication. A wired or wireless communication from a first base station to a second base station is referred to as a backhaul communication.

Resources are required to perform uplink, downlink and sidelink communications. For example, a base station may wirelessly transmit data, such as a transport block (TB), to a UE in a downlink transmission at a particular frequency and over a particular duration of time. The frequency and time duration used are examples of resources.

In a half-duplex communication system, a transceiver stops receiving while transmitting or stops transmitting while receiving. In a full duplex (FD) communication system, transceivers communicate with each other at the same time, reducing the latency of two-way communications. Some FD schemes allow the transceivers to transmit and receive over different frequency bandwidth, which effectively reduces or eliminates the interference between two parallel links (e.g., from point A to point B, from point B to point A). Some other FD schemes pursue simultaneous bi-directional communication over the same frequency bandwidth and hence provide improved spectrum utilization. The FD schemes over the same or overlapped frequency bandwidth need effective mitigation of self-interference (between the transmitter and receiver of the transceiver).

SUMMARY

Aspects of the present disclosure provide a manner of avoiding a problem of excessive latency and resource consumption due to exhaustive beam searching and pairing for finding an appropriate bi-directional beam pair combination with manageable mutual interference to enable point-to-point FD transmission. Aspects of the present disclosure also provide a solution for enabling multi-user transmission, i.e. by neighboring UEs where one or all UEs are with FD capability and the cross-UE interference raised from FD transmission are measured and taken into account during multi-user pairing.

The terms cross-UE interference and UE cross interference and UE cross interference maybe used interchangeably in the document to mean interference that occurs between transmit and receive beams of neighboring UEs. The self-interference status may be represented by self-interference or self-isolation, which may reflect amount or level of interference. Furthermore, the self-interference and self-isolation that are each referred to in this document generally refer to a similar aspect of how much interference occurs between transmit and receive beams of a same network element such as transmit and receive beams of a UE or transmit and receive beams of a base station. When self-interference is used, it refers to the amount or level of interference. When self-isolation is used, it refers the level of isolation, reflecting the amount or level of interference but in a different measuring direction. For example, when self-interference is high, the self-solation is deemed relatively low; when self-interference is low, the self-isolation is deemed relatively high. Therefore, when one expression is used, it is to be understood that the other term may also apply.

In some embodiments, by allowing the UE to select and report one or more possible transmit and receive beam pairs for FD transmission and corresponding self-interference/isolation levels, it is possible that the transmit and receive beam pairs at the UE that are not suitable for FD transmission will be deprioritized. Furthermore, the transmit and receive beam pairs that provide less self-interference, or better self-isolation, may be prioritized and tested within a first few measurement opportunities. In some embodiments, this may lead to a further reduction in latency and improved resource utilization.

In some embodiments, introducing information sharing via sidelink, i.e. sharing the selected base station transmit beam or UE transmit beam for each SRS for self-interference/isolation estimation, or both, the beam selection at multiple UEs can be better coordinated for the purpose of multi-UE FD transmission. This can potentially increase the success rate of multi-UE FD transmission and lowering latency.

In some embodiments, introducing pre-defined, configured or a reported association between the SRS for self-interference/isolation estimation and the SRS for cross-UE interference measurement, it is possible to improve the interference measurement assumption including UE receive beamforming between the base station and the UEs being served by the base station, which may lead to an improved efficiency for multi-user FD transmissions.

According to some aspects, there is provided a method involving: receiving, by an apparatus, configuration information comprising a set of candidate beams; transmitting, by the apparatus, a reference signal (RS) on a first beam identified in the set of candidate beams; measuring, by the apparatus, interference signal strength of the RS on a second beam identified in the set of candidate beams; determining, by the apparatus, self-interference for the first and second beams based on the measured interference strength signal; selecting an apparatus transmit and apparatus receive beam pair from the set of candidate beams based on the determined self-interference; and transmitting, by the apparatus to a base station, identification of the apparatus transmit and apparatus receive beam pair.

In some embodiments, the set of candidate beams are apparatus transmit and apparatus receive beams that could be used for full duplex communication between the apparatus and the base station.

In some embodiments, the set of candidate beams are based on measurement of at least one of: channel state information reference signals (CSI-RS) received on a plurality of beams at the apparatus; positioning reference signals (PRS) received on a plurality of beams at the apparatus; tracking reference signals (TRS) received on a plurality of beams at the apparatus; synchronization signals/physical broadcast channel (SS/PBCH) resource block received on a plurality of beams at the apparatus; sounding reference signals (SRS) transmitted on a plurality of beams at the apparatus; physical uplink control channel (PUCCH) transmitted on a plurality of beams at the apparatus; or random access channel (RACH) transmitted on a plurality of beams at the apparatus.

In some embodiments, the method further involves: selecting an apparatus receive beam that: is suitable for downlink reception with the base station transmit beam notified by the neighbor UE; or is suitable for downlink reception with a base station transmit beam that is spatially distant from the base station transmit beam notified by the neighbor UE.

In some embodiments, the configuration information identifies a candidate beam in the set of candidate beams by: an angle or a range of angle that the apparatus or the base station, or both, are beamforming to receive from or transmit towards; or a sector number where the apparatus or the base station, or both, are covering by beamforming.

In some embodiments, the computer executable instructions that cause the apparatus to select the apparatus transmit and apparatus receive beam pair from the set of candidate beams, further cause the apparatus to select a apparatus receive beam that: is suitable for downlink reception with the base station transmit beam notified by the neighbor UE; or is suitable for downlink reception with a base station transmit beam that is spatially distant from the base station transmit beam notified by the neighbor UE.

In some embodiments, the configuration information identifies a candidate beam in the set of candidate beams by: an angle or a range of angle that the apparatus or the base station, or both, are beamforming to receive from or transmit towards; or a sector number where the apparatus or the base station, or both, are covering by beamforming.

In some embodiments, the method further involves: receiving, by the apparatus, configuration information for measurement of a channel state information reference signal (CSI-RS) by the apparatus; receiving, by the apparatus, the CSI-RS transmitted by the base station; measuring, by the apparatus, signal strength information pertaining to the CSI-RS; and transmitting, by the apparatus to the base station, the signal strength information.

In some embodiments, the method further involves receiving, by the apparatus, configuration information for transmission of a sounding reference signal (SRS); and transmitting, by the apparatus, the SRS.

According to some aspects, there is provided an apparatus including a processor and a computer-readable medium. The computer-readable medium has stored thereon computer executable instructions, that when executed cause the apparatus to: receive configuration information comprising a set of candidate beams; transmit a reference signal (RS) on a first beam identified in the set of candidate beams; measure interference signal strength of the RS on a second beam identified in the set of candidate beams; determine self-interference for the first and second beams based on the measured interference strength signal; select an apparatus transmit and apparatus receive beam pair from the set of candidate beams based on the determined self-interference; and transmit to a base station identification of the apparatus transmit and apparatus receive beam pair.

In some embodiments, the set of candidate beams are apparatus transmit and apparatus receive beams that could be used for full duplex communication between the apparatus and the base station.

In some embodiments, the set of candidate beams are based on measurement of at least one of: channel state information reference signals (CSI-RS) received on a plurality of beams at the apparatus; positioning reference signals (PRS) received on a plurality of beams at the apparatus; tracking reference signals (TRS) received on a plurality of beams at the apparatus; synchronization signals/physical broadcast channel (SS/PBCH) resource block received on a plurality of beams at the apparatus; sounding reference signals (SRS) transmitted on a plurality of beams at the apparatus; physical uplink control channel (PUCCH) transmitted on a plurality of beams at the apparatus; or random access channel (RACH) transmitted on a plurality of beams at the apparatus.

In some embodiments, the computer executable instructions, when executed, further cause the apparatus to: receive configuration information for measurement of the CSI-RS by the apparatus; receive the CSI-RS transmitted by the base station; measure signal strength information pertaining to the CSI-RS; and transmit to the base station, the signal strength information.

In some embodiments, the computer executable instructions, when executed, further cause the apparatus to receive configuration information for transmission of the SRS; and transmit the SRS.

According to some aspects, there is provided a method involving: transmitting, by a base station, configuration information comprising a set of candidate beams; receiving, by the base station from a user equipment (UE), identification of an UE transmit and UE receive beam pair from the set of candidate beams based on a determined self-interference, the self-interference determined based on isolation interference measured between first and second beams at the UE.

In some embodiments, the method further involves: transmitting, by the base station, configuration information for measurement of the CSI-RS by the UE; transmitting, by the base station, the CSI-RS; receiving, by the base station from the UE, signal strength information measured by the UE; and selecting the set of candidate beams based on the received signal strength information measured by the UE to transmit in the configuration information.

In some embodiments, the method further involves: transmitting, by the base station, configuration information for transmission of the SRS; receiving, by the base station, the SRS; measuring, by the base station, signal strength information pertaining to the SRS; and selecting the set of candidate beams based on the measured signal strength information pertaining to the SRS to transmit in the configuration information.

In some embodiments, the set of candidate beams are UE transmit and UE receive beams that could be used for full duplex communication between the base station and the UE.

In some embodiments, the method further involves: receiving, at the base station, an identification of at least one of: a self-interference or self-isolation value between a UE transmit beam and a UE receive beam of a selected UE transmit and UE receive beam pair; or an occasion or index of reference signal transmission by the apparatus.

In some embodiments, the set of candidate beams based on measurement of at least one of: channel state information reference signals (CSI-RS) transmitted on a plurality of beams at the base station; positioning reference signals (PRS) received on a plurality of beams at the apparatus; tracking reference signals (TRS) received on a plurality of beams at the apparatus; synchronization signals/physical broadcast channel (SS/PBCH) resource block received on a plurality of beams at the apparatus; sounding reference signals (SRS) transmitted on a plurality of beams at the UE; physical uplink control channel (PUCCH) transmitted on a plurality of beams at the apparatus; or random access channel (RACH) transmitted on a plurality of beams at the apparatus.

In some embodiments, the configuration information identifies a candidate beam in the set of candidate beams by: an angle or a range of angle that the UE or the base station, or both, are beamforming to receive from or transmit towards; or a sector number where the UE or the base station, or both, are covering by beamforming.

According to some aspects, there is provided an apparatus including a processor and a computer-readable medium. The computer-readable medium has stored thereon computer executable instructions, that when executed, cause the apparatus to: transmit configuration information comprising a set of candidate beams; receive from a user equipment (UE), identification of a UE transmit and UE receive beam pair from the set of candidate beams based on a determined highest self-interference, the self-interference determined based on isolation interference measured between first and second beams at the UE.

In some embodiments, the computer executable instructions, when executed, further cause the apparatus to: transmit configuration information for measurement of the CSI-RS by the UE; transmit the CSI-RS; receive from the UE signal strength information measured by the UE; and select the set of candidate beams based on the received signal strength information measured by the UE to transmit in the configuration information.

In some embodiments, the computer executable instructions, when executed, further cause the apparatus to: transmit configuration information for transmission of the SRS; receive the SRS; measure signal strength information pertaining to the SRS; and select the set of candidate beams based on the measured signal strength information pertaining to the SRS to transmit in the configuration information.

In some embodiments, the set of candidate beams are UE transmit and UE receive beams that could be used for full duplex communication between the apparatus and the base station.

In some embodiments, the computer executable instructions, that when executed, further cause the apparatus to receive to the base station an identification of at least one of: a self-interference or self-isolation value between a transmit beam and a receive beam of a selected transmit and receive beam pair; or an occasion or index of reference signal transmission by the apparatus.

In some embodiments, the set of candidate beams that could be used for full duplex communication between the base station and the UE are based on measurement of at least one of: channel state information reference signals (CSI-RS) transmitted on a plurality of beams between the base station and the UE; positioning reference signals (PRS) received on a plurality of beams at the apparatus; tracking reference signals (TRS) received on a plurality of beams at the apparatus; synchronization signals/physical broadcast channel (SS/PBCH) resource block received on a plurality of beams at the apparatus; sounding reference signals (SRS) transmitted on a plurality of beams between the UE and the base station; physical uplink control channel (PUCCH) transmitted on a plurality of beams at the apparatus; or random access channel (RACH) transmitted on a plurality of beams at the apparatus.

In some embodiments, the configuration information identifies a candidate beam in the set of candidate beams by: an angle or a range of angle that the UE or the base station, or both, are beamforming to receive from or transmit towards; or a sector number where the UE or the base station, or both, are covering by beamforming.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

For illustrative purposes, specific example embodiments will now be explained in greater detail below in conjunction with the figures.

The embodiments set forth herein represent information sufficient to practice the claimed subject matter and illustrate ways of practicing such subject matter. Upon reading the following description in light of the accompanying figures, those of skill in the art will understand the concepts of the claimed subject matter and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

There are various ways involving self-interference suppression and/or cancellation methods in both the analog and digital domains that have been studied to enable transceivers to transmit and receive simultaneously over the same frequency bandwidth. One particular method, is to apply transmit and receive beamforming, often categorized as in propagation or the analog domain. The key point of such method is to find appropriate beamforming patterns providing manageable cross-direction interference to enable simultaneous bi-directional communications. This is illustrated inFIG.1A, where FD communication100is shown between one base station101and one UE102. The base station101is shown having two antenna panels103a,103bthat each have three beams shown covering a portion of a coverage area. The UE102is shown having three antenna panels105a,105b,105c, two of which are shown having three beams shown coving a portion of a coverage area. One base station transmit beam and one UE receive beam is considered a beam pair and one base station receive beam and one UE transmit beam is considered a beam pair. Therefore, two pairs are needed for FD transmission, where one is used for downlink (DL) and the other is used for uplink (UL). A DL channel is shown to include a transmit/receive pair that include base station transmit beam104aand UE receive beam106a. A UL channel is shown to include a transmit/receive pair that include UE transmit beam106band base station receive beam104b. There is some level of isolation between base station transmit beam104aand base station receive beam104bas these two beams are directed in different directions. There is some level of isolation between UE transmit beam106aand UE receive beam106bas these two beams are directed in different directions.

While the case of BS-to-UE transmission is shown as an example, the concept of FD can naturally be extended to BS-to-BS (backhaul) or UE-to-UE (sidelink) cases.

Furthermore, unless otherwise stated, it is assumed that when UEs are referred to in this description, they are FD capable UEs, that is UEs that are enabled to perform full duplex functionality. UEs that are enabled to perform full duplex functionality are also typically able to perform half duplex functionality. When UEs are indicated to be non-FD capable, they are at least capable of half duplex.

There are several straightforward solutions that can be considered to enable FD. One solution is to exhaust all possible combinations of beam pairs between the transceivers, and find the most suitable combination of beam pairs. This solution is overwhelming in terms of time and resource consumption.FIG.1Bshows this described solution110in which a base station111has beams associated with two antenna panels and a UE112has beams associated with two antenna panels. Transmit/receive beams pairs are determined for DL113and114with suitable isolation between the transmit beam and receive beam at the base station and at the UE. Transmit/receive beams pairs are determined for UL115and116with suitable isolation between the transmit beam and receive beam at the base station and at the UE. This method is more suitable for feasibility verification in a laboratory, which is stationary and there is sufficient time to finish such exhaustive searching.

Another solution is to let one transceiver dictate the beam pair for one direction (based on previous beam training for this direction), and then leaving the choice of the beam pair for the other direction to the other party in the communication. This method is likely to be able to provide high suppression of self-interference, but with less guarantee on the quality of service (QoS) on the other direction and the flexibility of beam pairing may also be somewhat restricted.FIG.1Bshows this described solution120in which a base station121has beams associated with two antenna panels and a UE122has beams associated with two antenna panels. A transmit/receive beam pair is determined for DL123for one transmit/receive beam pair for the first antenna panel. A transmit/receive beam pair is determined from the various beams options shown for UL124as a single transmit/receive beam pair for the second antenna panel to enable suitable isolation between the base station transmit beam of the first base station antenna panel and base station receive beam of the second base station antenna panel and the UE receive beam of the first UE antenna panel and UE transmit beam of the second UE antenna panel.

In cellular communication systems with one base station serving multiple UEs, as a means to improve overall system capacity, multi-user concurrent transmission where the base station transmits to, or receives from, multiple UEs simultaneously is becoming more and more popular. When the base station and the UE are both capable of FD transmission, there has not been a solution available for enabling UE pairing considering UE-to-UE interference, which results from simultaneous transmission and reception of multiple UEs and does not exist in half-duplex multi-user transmissions where UEs are either all receiving or all transmitting.FIG.10illustrates an example130of a base station having transmit and receive beams and two FD capable UEs, UE #1and UE #2, that each have respective transmit and receive beams. Because the UEs are capable of FD, each of the UEs is shown to have a UE transmit/receive beam pair, UE #1having one UE transmit/receive beam pair for DL132b,134band UE #2having one transmit/receive beam pair for UL132a,134a. It is also possible that not all of the UEs being served by a base station would be able to support FD transmission. Therefore, pairing FD enabled and non-FD enabled UEs should be considered.FIG.10illustrates an example140of a base station having transmit and receive beams and one FD capable UE, UE #1, having transmit and receive beams and one UE that is not FD capable, UE #2, having a receive beam. The FD capable UE is shown to be using one UE transmit/receive beam pair for DL142band one transmit/receive beam pair for UL142a, while the UE #2that is not FD capable is only able of DL144from the base station on a beam pair including the base station transmit beam and the UE receive beam. Example150illustrates the situation in which the FD capable UE. UE #1, is able to transmit and receive simultaneously on UE transmit/receive beam pairs for DL152band UL152aand the UE that is not FD capable, UE #2, can perform UL154from the base station on a beam pair including the UE transmit beam and base station receive beam.

Aspects of the present disclosure provide a manner of avoiding a problem of excessive latency and resource consumption due to exhaustive beam searching and pairing for finding an appropriate bi-directional beam pair combination with manageable mutual interference to enable point-to-point FD transmission. Aspects of the present disclosure also provide a solution for enabling multi-user transmission where one or all UEs are with FD capability and the cross-UE interference raised from FD transmission are measured and taken into account during multi-user pairing.

FIGS.2,3A, and3Bfollowing below provide context for the network and device that may be in the network and that may implement aspects of the present disclosure.

FIG.2illustrates an example communication system100in which embodiments of the present disclosure could be implemented. In general, the system100enables multiple wireless or wired elements to communicate data and other content. The purpose of the system100may be to provide content (voice, data, video, text) via broadcast, narrowcast, user device to user device, etc. The system100may operate efficiently by sharing resources such as bandwidth. [007o] In this example, the communication system100includes electronic devices (ED)110a-110c, radio access networks (RANs)120a-120b, a core network130, a public switched telephone network (PSTN)140, the Internet150, and other networks160. While certain numbers of these components or elements are shown inFIG.2, any reasonable number of these components or elements may be included in the system100.

The EDs110a-110care configured to operate, communicate, or both, in the system100. For example, the EDs110a-110care configured to transmit, receive, or both via wireless communication channels. Each ED110a-110crepresents any suitable end user device for wireless operation and may include such devices (or may be referred to) as a user equipment/device (UE), wireless transmit/receive unit (VVTRU), mobile station, mobile subscriber unit, cellular telephone, station (STA), machine type communication device (MTC), personal digital assistant (PDA), smartphone, laptop, computer, touchpad, wireless sensor, consumer electronics device, Internet of Things (loT) device, wearable device, or vehicular device (or vehicle-mounted device, vehicle on-board equipment).

FIG.2illustrates an example communication system100in which embodiments of the present disclosure could be implemented. In general, the communication system100enables multiple wireless or wired elements to communicate data and other content. The purpose of the communication system100may be to provide content (voice, data, video, text) via broadcast, multicast, unicast, user device to user device, etc. The communication system100may operate by sharing resources such as bandwidth.

In this example, the communication system100includes electronic devices (ED)110a-110c, radio access networks (RANs)120a-120b, a core network130, a public switched telephone network (PSTN)140, the internet150, and other networks160. Although certain numbers of these components or elements are shown inFIG.2, any reasonable number of these components or elements may be included in the communication system100.

The EDs110a-110care configured to operate, communicate, or both, in the communication system100. For example, the EDs110a-110care configured to transmit, receive, or both, via wireless or wired communication channels. Each ED110a-110crepresents any suitable end user device for wireless operation and may include such devices (or may be referred to) as a user equipment/device (UE), wireless transmit/receive unit (VVTRU), mobile station, fixed or mobile subscriber unit, cellular telephone, station (STA), machine type communication (MTC) device, personal digital assistant (PDA), smartphone, laptop, computer, tablet, wireless sensor, or consumer electronics device.

InFIG.2, the RANs120a-120binclude base stations170a-170b, respectively. Each base station170a-170bis configured to wirelessly interface with one or more of the EDs110a-110cto enable access to any other base station170a-170b, the core network130, the PSTN140, the internet150, and/or the other networks160. For example, the base stations170a-170bmay include (or be) one or more of several well-known devices, such as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNodeB), a Home eNodeB, a gNodeB, a transmission and receive point (TRP), a site controller, an access point (AP), or a wireless router. Any ED110a-110cmay be alternatively or additionally configured to interface, access, or communicate with any other base station170a-170b, the internet150, the core network130, the PSTN140, the other networks160, or any combination of the preceding.

The EDs110a-110cand base stations170a-170bare examples of communication equipment that can be configured to implement some or all of the functionality and/or embodiments described herein. In the embodiment shown inFIG.2, the base station170aforms part of the RAN120a, which may include other base stations, base station controller(s) (BSC), radio network controller(s) (RNC), relay nodes, elements, and/or devices. Any base station170a,170bmay be a single element, as shown, or multiple elements, distributed in the corresponding RAN, or otherwise. Also, the base station170bforms part of the RAN120b, which may include other base stations, elements, and/or devices. Each base station170a-170btransmits and/or receives wireless signals within a particular geographic region or area, sometimes referred to as a “cell” or “coverage area”. A cell may be further divided into cell sectors, and a base station170a-170bmay, for example, employ multiple transceivers to provide service to multiple sectors. In some embodiments, there may be established pico or femto cells where the radio access technology supports such. In some embodiments, multiple transceivers could be used for each cell, for example using multiple-input multiple-output (MIMO) technology. The number of RAN120a-120bshown is exemplary only. Any number of RAN may be contemplated when devising the communication system100.

The base stations170a-170bcommunicate with one or more of the EDs110a-110cover one or more air interfaces190using wireless communication links e.g. radio frequency (RF), microwave, infrared (IR), etc. The air interfaces190may utilize any suitable radio access technology. For example, the communication system100may implement one or more orthogonal or non-orthogonal channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA) in the air interfaces190.

A base station170a-170bmay implement Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access (UTRA) to establish an air interface190using wideband CDMA (WCDMA). In doing so, the base station170a-170bmay implement protocols such as High Speed Packet Access (HSPA), Evolved HPSA (HSPA+) optionally including High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA) or both. Alternatively, a base station170a-170bmay establish an air interface190with Evolved UTMS Terrestrial Radio Access (E-UTRA) using LTE, LTE-A, and/or LTE-B. It is contemplated that the communication system100may use multiple channel access functionality, including such schemes as described above. Other radio technologies for implementing air interfaces include IEEE 802.11, 802.15, 802.16, CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, IS-2000, IS-95, IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemes and wireless protocols may be utilized.

The RANs120a-120bare in communication with the core network130to provide the EDs110a-110cwith various services such as voice, data, and other services. The RANs120a-120band/or the core network130may be in direct or indirect communication with one or more other RANs (not shown), which may or may not be directly served by core network130, and may or may not employ the same radio access technology as RAN120a, RAN120bor both. The core network130may also serve as a gateway access between (i) the RANs120a-120bor EDs110a-110cor both, and (ii) other networks (such as the PSTN140, the internet150, and the other networks160).

The EDs110a-110ccommunicate with one another over one or more SL air interfaces180using wireless communication links e.g. radio frequency (RF), microwave, infrared (IR), etc. The SL air interfaces180may utilize any suitable radio access technology, and may be substantially similar to the air interfaces190over which the EDs110a-110ccommunication with one or more of the base stations170a-170c, or they may be substantially different. For example, the communication system100may implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA) in the SL air interfaces180. In some embodiments, the SL air interfaces180may be, at least in part, implemented over unlicensed spectrum.

In addition, some or all of the EDs110a-110cmay include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and/or protocols. Instead of wireless communication (or in addition thereto), the EDs may communicate via wired communication channels to a service provider or switch (not shown), and to the internet150. PSTN140may include circuit switched telephone networks for providing plain old telephone service (POTS). Internet150may include a network of computers and subnets (intranets) or both, and incorporate protocols, such as internet protocol (IP), transmission control protocol (TCP) and user datagram protocol (UDP). EDs110a-110cmay be multimode devices capable of operation according to multiple radio access technologies, and incorporate multiple transceivers necessary to support multiple radio access technologies.

FIGS.3A,3B and3Cillustrate example devices that may implement the methods and teachings according to this disclosure. In particular,FIG.3Aillustrates an example ED110, andFIGS.3B and3Ceach illustrate example base stations170. These components could be used in the system100or in any other suitable system.

As shown inFIG.3A, the ED110includes at least one processing unit or processor200. The processing unit200implements various processing operations of the ED110. For example, the processing unit200could perform signal coding, data processing, power control, input/output processing, or any other functionality enabling the ED110to operate in the communication system100. The processing unit200may also be configured to implement some or all of the functionality and/or embodiments described in more detail herein. Each processing unit200includes any suitable processing or computing device configured to perform one or more operations. Each processing unit200could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

The ED110also includes a transmitter202. The transmitter202is configured to modulate data or other content for transmission by at least one antenna or Network Interface Controller (NIC)204. The ED110also includes a receiver204. The receiver204is configured to demodulate data or other content received by at least one antenna205. The transmitter202and receiver204includes any suitable structure for generating signals for wireless or wired transmission and/or processing signals received wirelessly or by wire. Each antenna204and205each includes any suitable structure for transmitting (antenna204) and/or receiving (antenna205) wireless or wired signals. One or multiple transmitters202and receivers204could be used in the ED110. One or multiple transmit antennas204or receive antennas205could be used in the ED110. One or more of the antennas204,205may each have one or more antenna panels. Although shown as a separate transmitter and receiver functional units, these devices could also be implemented using at least one transceiver. WhileFIG.3Aillustrates the base station including two antennas, in other embodiments, both the transmitter and receiver, or a transceiver, may be connected to a single antenna, having one or more antenna panels.

The ED110further includes one or more input/output devices206or interfaces (such as a wired interface to the internet150). The input/output devices206permit interaction with a user or other devices in the network. Each input/output device206includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.

In addition, the ED110includes at least one memory208. The memory208stores instructions and data used, generated, or collected by the ED110. For example, the memory208could store software instructions or modules configured to implement some or all of the functionality and/or embodiments described above and that are executed by the processing unit(s)200. Each memory208includes any suitable volatile and/or non-volatile storage and retrieval device(s). Any suitable type of memory may be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, and the like.

As shown inFIG.3B, the base station170includes at least one processing unit or processor250, at least one transmitter252, at least one receiver254, one or more antennas256, at least one memory258, and one or more input/output devices or interfaces266. A scheduler253may be coupled to the processing unit250. The scheduler253may be included within or operated separately from the base station170. The processing unit250implements various processing operations of the base station170, such as signal coding, data processing, power control, input/output processing, or any other functionality. The processing unit250can also be configured to implement some or all of the functionality and/or embodiments described in more detail above. Each processing unit250includes any suitable processing or computing device configured to perform one or more operations. Each processing unit250could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

Each transmitter252includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each receiver254includes any suitable structure for processing signals received wirelessly or by wire from one or more EDs or other devices. Although shown as separate components, at least one transmitter252and at least one receiver254could be combined into a transceiver. Each antenna256includes any suitable structure for transmitting and/or receiving wireless or wired signals. Although a common antenna256is shown here as being coupled to both the transmitter252and the receiver254, one or more antennas256could be coupled to the transmitter(s)252, and one or more separate antennas256could be coupled to the receiver(s)254. Each memory258includes any suitable volatile and/or non-volatile storage and retrieval device(s) such as those described above in connection to the ED110. The memory258stores instructions and data used, generated, or collected by the base station170. For example, the memory258could store software instructions or modules configured to implement some or all of the functionality and/or embodiments described above and that are executed by the processing unit(s)250.

Each input/output device266permits interaction with a user or other devices in the network. Each input/output device266includes any suitable structure for providing information to or receiving/providing information from a user, including network interface communications.

FIG.3Cin another version of the base station170that shows many of the same elements asFIG.3B. In particular, the base station170includes at least one processing unit250, at least one transmitter252, at least one receiver254, at least one memory258, and one or more input/output devices or interfaces266. A scheduler253may be coupled to the processing unit250. The main difference betweenFIGS.3B and3Cis that there are two antennas256,257, one coupled to each of the transmitter252and the receiver254, respectively. The same numbered elements in the two figures have similar functionality.

Each transmitter252includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each receiver254includes any suitable structure for processing signals received wirelessly or by wire from one or more EDs or other devices. Although shown as separate components, at least one transmitter252and at least one receiver254could be combined into a transceiver. Each of the antennas256,257includes any suitable structure for transmitting (antenna256) and/or receiving (antenna257) wireless or wired signals. Although a single transmit antenna256is shown coupled to the transmitter252and a single receive antenna257is shown coupled to the receiver254, more than one antenna could be coupled to either the transmitter252or the receiver254. Furthermore, each antenna256,257may include one or more antenna panels.

Additional details regarding the UEs110and the base stations170are known to those of skill in the art. As such, these details are omitted here for clarity.

In existing 3GPP specifications, a beamforming behavior at the base station side is often unspecified, while the beamforming behavior at the UE side is often captured with more details. The concept of a beam pair consisting of one beam at the base station and one beam at the UE was used above and inFIG.1Afor illustration purposes. Aspects of the following description will describe the beamforming behavior at the UE side and beam pairing mainly refers to pairing the transmit beam and receive beam at the UE side.

Referring now to the arrangement ofFIG.4, the figure includes a UE410illustrated to have two antenna panels that can transmit or receive on multiple beams and a base station420. While not shown inFIG.4, the base station420may also have multiple antenna panels each having multiple transmit and receive beams, as shown for example inFIG.1A. In some embodiments, the following functionality can be performed to find an appropriate transmit and receive beam pair at the UE for FD transmission for point-to-point transmission.1. The base station shares a candidate beam set that include an identification of one or more beams with the UE. The candidate beam set is selected based on previous beam training results performed with the UE and/or the current interference situation, so as to allow an exhaustive search over all possible combinations of beams at the base station and the UE to be avoided, thereby reducing latency and improving resource utilization.2. The UE selects430two beams, for example a first beam and a second beam, among the candidate beam set provided by the base station, one is for reception and the other is for transmission from the UE perspective. The UE then transmits a reference signal on a first beam, which is transmit beam440a, an example of which is a sounding reference signal (SRS). Transmission on transmit beam440acan be measured on a second beam identified in the candidate beam set, which is receive beam450ato determine self-interference460and on another second beam, receive beam450b, to determine self-interference470. Transmission on another first beam, transmit beam440b, can be measured on receive beam450ato determine self-interference480and on receive beam450bto determine self-interference490. By measuring the level of self-interference or self-isolation, the UE can determine which beam pairs lead to strong self-interference, and can therefore be ruled out as further candidates, and the beam pairs that have better self-isolation. In this case the worst self-interference appears to be between beams440band450aand best self-isolation appears to be between beams440aand450b.3. Based on the measured results, the UE reports495the selected beams for transmission and reception respectively, and the measured level of self-interference or self-isolation, so to facilitate future FD transmission with the base station. In some embodiments, a preferred occasion of SRS transmission may also be reported to the base station.

When multiple UEs may be communicating with a same base station, additional functionality may be provided that enables the UEs to determine cross-UE interference and facilitate multi-UE FD pairing with the base station. Examples the additional functionality may include:1. Via sidelink transmission between two UEs, one UE shares information on a selected base station transmit beam and thereby corresponding UE receive beam for receiving SRS for self-interference/isolation estimation, so as to facilitate neighbor UEs to measure cross-UE interference by applying the receive beam that can be used to receive from the same base station transmit beam to receive the SRS transmission from the UE, which can for example enable the base station to use the same transmit beam to transmit towards those UEs.2. Via sidelink, one UE shares information on selected base station transmit beam and thereby corresponding UE receive beam for receiving SRS for self-interference/isolation estimation, so as to facilitate neighbor UEs to measure cross-UE interference by applying the receive beam that can be used to receive from the base station transmit beam that is spatially distant from the base station transmit beam to receive the SRS transmission from the UE, which can for example enable the BS to use spatially distant transmit beams to transmit towards those UEs.3. Via sidelink, the UE shares information on selected UE transmit beams, among those previously applied in sidelink beam training, for transmitting the SRS for self-interference/isolation estimation, so as to facilitate neighbor UEs to select the receive beam for measuring and mitigating cross-UE interference with potential interference avoidance schemes applied.4. From one UE perspective, for a given combination of SRS for self-interference/isolation estimation for this UE and SRS for cross-UE interference measurement (containing SRS configuration of neighbor UEs), the UE reports to the base station about the measured cross-UE interference, where the association between SRS for self-interference/isolation estimation and SRS for cross-UE interference measurement can also be proactively selected and reported by the UE.

Methods of acquiring UE transmit and receive beam pairs with manageable cross-direction interference for enabling point-to-point FD transmission will now be described in detail.

Measurement Configuration

As a preliminary step to what is described above as the functionality occurring between a base station and a UE to determine transmit/receive beam pairs with reduced self-interference, it is assumed that beam training, has been performed for the base station-to-UE link (DL) or for the UE-to-base station link (UL), or both. Beam training may include the process of acquiring the beam(s) at the base station and/or the UE that can be used for communication between the base station and UE. The beam training results for DL are reported from the UE to the base station via beam reporting, where one or more of resource indication information, such as synchronization signals/physical broadcast channel (SS/PBCH) resource block indicator (SSBRI) or channel state information reference signal (CSI-RS) resource indicator (CRI) and corresponding layer 1—reference signal received power/signal interference to noise ratio (L1-RSRP/SINR) are provided. Here SSBRI and CRI represents the selected transmit beam at the base station side. In some embodiments, for given base station transmit beams, if there is no explicit indication from the base station about which UE receive beam should be used, the UE may select receive beams, measure a respective corresponding signal strength and send feedback to the base station. In such a situation, the reported SSBRI/CRI represents the selected base station transmit beam and UE receive beam, which is known at the UE only. After getting the SSBRI/CRI, the base station knows which beam to use to transmit to the UE. For future transmission, if the base station indicates the previously reported SSB/CSI-RS for the UE to determine the receive beam, the UE knows it should be using the corresponding receive beam, or a similar receive beam. L1-RSPR/SINR represents the observed channel quality given the selected base station transmit beam and possibly an associated UE receive beam. The L1-RSPR/SINR is either determined by the UE itself or indicated to the UE by the base station. The beam training results for UL are known to the base station via previous transmissions of sounding reference signal (SRS) and the corresponding channel quality measurements, which can be selected by the base station and indicated to the UE for subsequent transmissions.

For FD transmission, to enable UE transmit and receive beam pairing for UL and DL, in which the beam pair is a UE transmit beam and a UE receive beam, and estimation of self-interference/self-isolation at the UE, the base station configures SRS transmission for the UE. An example of the information element (IE) that may be used to configure the SRS is an IE of SRS resource set (srs-ResourceSet) which is shown inFIG.5. An IE is a group of fields for different information which may be included within a signaling message or data flow and sent across a communication interface. A field in the srs-ResourceSet IE is a SRS resource set ID (srs-ResourceSetId1) field that indicates an identifier (ID) of a set of SRS resource(s) that can be used for self-interference/isolation estimation. Another field in the srs-ResourceSet IE is a SRS resource ID list (srs-ResourceldList) field that identifies the IDs of SRS resources contained in the SRS resource set with an ID of srs-ResourceSetId1, which can be used for self-interference/isolation estimation.

It is expected the UE may use a transmit beam to transmit a configured SRS and receive the transmitted SRS on a receive beam at the same time. In this way, the self-interference, or equivalently the level of self-isolation, can be measured. By comparing different combinations of transmit and receive beams at the UE, a pair of UE transmit and UE receive beams that provide manageable self-interference, or satisfactory self-isolation, can be identified. However, given that the number of different UE transmit and UE receive beams at the UE can be somewhat large, it would take many SRS transmission opportunities to perform the SRS transmissions to exhaust all the possible combinations, leading to a large delay and resource overhead. Instead of letting the UE exhaust all possible combinations of transmit and receive beams at the UE, the base station can provide assistance information to restrict UE transmit and receive beam selection to a candidate beam set. This candidate beam set can be formed utilizing previous DL and UL beam training results. The candidate beam sent can include one or multiple UE transmit beams or one or multiple UE receive beams, or both for the eventual selection of a UE transmit and UE receive beam pair. For example, by selecting beam candidates with L1-RSRP/SINR values above a certain threshold. As shown inFIG.5, an example IE for configuring SRS for self-interference/isolation estimation may include additional optional fields such as a CSI-RS resource set ID (csi-rs-ResourceSetId) field and a SRS resource set ID (srs-ResourceSetId2) field that indicate IDs of CSI-RS and SRS resource(s) that can be used to identify candidate UE transmit and receive beams. It is noted that the srs-ResourceSetId1 and srs-ResourceSetId2 are two exemplary names of the fields for resource set. The fields could be in other names may distinguish the resource sets.

Whether the UE can generate a transmit beam that is exactly the same (or within a certain error margin under certain probability) as a receive beam is referred to as whether beam correspondence (BC) holds at the UE or not. With BC, the SS/PBCH or CSI-RS represented by SSBRI/CRI that is reported in the previously performed DL beam reporting can be used to indicate the transmit beam for UL transmission. Without BC, UL beam training is often needed, and the SRS representing the transmit beam selected from UL beam training can be used to indicate the transmit beam for UL transmission. Depending on whether BC occurs at the UE or not, the candidate beam set mentioned above can be conveyed from the base station to the UE in different manners.

If BC holds, for the SRS for self-interference/isolation estimation, the base station can indicate to the UE a set of SSB and/or CSI-RS, which are likely derived from the previously performed DL beam reporting. This indication provides the candidate beam set for the UE to select from for transmitting and receiving each of the SRS for self-interference/isolation estimation. These previously reported SSB or CSI-RS implicitly represent the associated UE receive beams (and also transmit beam because of BC) at the UE. This example is illustrated in the first paragraph of the SRS-ResourceSet field descriptions ofFIG.6. Alternatively, the base station can indicate to the UE a set of SRS, which are likely derived from the previously performed UL beam training. The BS is allowed to configure UL beam training regardless of the BC status of the UE. The indication provides a candidate beam set for UE to select from for transmitting and receiving each of the SRS for self-interference/isolation estimation, as these previously transmitted SRS implicitly represent the associated UE transmit (Tx) beams (and also the receive beam because of BC) at the UE. This example is illustrated in the third paragraph ofFIG.6.

When BC does not hold, for the SRS to be used to determine self-interference/isolation estimation, the base station can indicate to the UE a set of SSB and/or CSI-RS, which are likely derived from the previously performed DL beam reporting, and a set of SRS, which are likely derived from previously performed UL beam training. The indicated SSB(s) and/or CSI-RS(s) are to provide the UE a candidate receive beam set for the UE to select from for receiving each of the SRS for self-interference/isolation estimation. The previously reported SSB or CSI-RS implicitly represent the associated UE receive beams at the UE. The indicated SRS(s) are to provide UE a candidate Tx beam set for UE to select for transmitting each of the SRS for self-interference/isolation estimation, as these (previously transmitted) SRS implicitly represent the associated UE Tx beam at this UE. This example is illustrated in the second paragraph ofFIG.6.

With such candidate beam set information received at the UE, it is expected that the UE receive or UE transmit beams that are not suitable for reception or transmission with the base station will be filtered out, leading to improved resource utilization compared with a blind exhaustive search at the UE side. In some embodiments, the UE will take initiative to prioritize the UE transmit and UE receive beam pairs that will likely lead to lower self-interference and high self-isolation, and which are more suitable for FD transmission, with which the chance of finding a proper UE transmit and UE receive beam pair may be faster than that performed by a blind network configuration.

During the above-mentioned process, if the UE panel information is available, the UE may be allowed to select UE transmit and UE receive beams for FD transmission from different UE panels, i.e., the CSI-RS or SRS provided for SRS for self-interference/isolation estimation representing different UE receive or UE transmit beams come from, or are mapped to different UE panels. The UE panel information may be provided by the UE to the base station in DL beam reporting and that indicates a base station transmit beam selected from the candidate set that is measured on the UE panel, or indicated by the base station to UE in UL beam training and that indicates a request for the UE to send SRS from a certain UE panel.

Processing and Reporting

For each of one or more beams of the candidate list, after transmitting and receiving the SRS, the UE measures self-interference/isolation from the transmitted and received SRS. The UE then selects one or more of the candidate beams of the candidate beam set that provides manageable self-interference or satisfactory self-isolation. The selecting of the one or more beams, which may include transmit and receive beams that collectively could be considered a transmit and receive beam pair, may be based on a transmit and receive beam pair with a highest self-isolation, a transmit and receive beam pair with a self-isolation not less than a threshold value, a transmit and receive beam pair with a lowest self-interference, or a transmit and receive beam pair with a self-interference not more than a threshold value. Based on these selection options, the one or more beams may include, for example, one beam pair if only the highest self-isolation or lowest self-interference is the basis of the selection, or multiple beam pairs if there are multiple beam pairs that have a self-isolation not less than a threshold value or a self-interference not more than a threshold value.

One or multiple choices of the selected SRS, the corresponding selected UE transmit and receive beams, the measured self-interference/isolation can be shared with the base station, so as to facilitate scheduling of FD transmissions. In some embodiments, information that is shared with the base station may include a self-interference or self-isolation value between a transmit beam and a receive beam of a selected transmit and receive beam pair. In some embodiments, information that is shared with the base station may include an occasion or an index value of a reference signal transmission as described in further detail below.

A possible way for the base station to configure the UE to perform reporting is using a IE such as the CSI report configuration (CSI-ReportConfig) IE shown inFIG.7. A SRS resource for self-interference (SRS-ResourcesForSelfl nterference) field defining the resources used to determine self-interference is included in the CSI-ReportConfig IE and where the report quality (report Quantity) field is set to sri-xri-xri-self-interference, where XRI stands for either SSBRI or CRI or SRS resource indicator (SRI). The reason behind this is the contents to be reported would depend on how the candidate beam set is conveyed to the UE, by {SSB and/or CSI-RS}, {SSB and/or CSI-RS+SRS}, or {SRS}. Such dependency is briefly described inFIG.8, and it is also noted that XRI to be reported is a relative index among these configured by the base station via csi-rs-ResouceSetld and srs-ResouceSetId2 inFIG.5.

Referring toFIG.9, which illustrates a series of events900occurring over a duration of time for selection of candidate beams, SRS self-interference estimate and reporting of a candidate selection by the UE, it can be seen that a transmission of SRS for self-interference/isolation estimation is triggered910by dynamic signaling by a DCI. After a particular time duration, that involves the UE selecting a UE transmit and UE receive beam from the candidate beam set, the UE transmits920the SRS. The particular time duration may be longer than when an SRS is triggered for other purposes, such as UL CSI acquisition. Another possible reason for the larger delay than regular SRS triggering is that the UE may need to wake up certain previously deactivated antenna panels for the selected UE transmit and UE receive beam pairing. The particular time duration may be captured as a triggering offset between the DCI and the transmission of the SRS. In some embodiments, the minimum delay between the DCI and the transmission of the SRS for self-interference/isolation estimation may be reported by the UE during UE capability reporting. In some embodiments, the triggering offset may be pre-configured with several candidate values, and then dynamically selected in the triggering DCI. In some embodiments, the minimum UE capability value or the minimum configured triggering offset for SRS for self-interference/isolation estimation, or both, is larger than that for SRS triggered for other purposes, respectively, so to ensure enough time is given to the UE for proper processing.

FIG.9illustrates the process for performing a self-interference/isolation estimation for a single candidate transmit and receive beam pair. Self-interference/isolation estimation can be performed for other candidate pairs subsequent to the first estimation910,920.

After the self-interference/isolation estimation has been performed for one or more candidates of the candidate set, the UE reports930one or more selected beam pairs to the network on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). The reporting may include such information as the selected SRS, one or more UE transmit and receive beam pairs, and one or more self-interference/isolation measurements. In some embodiments, a longer processing delay occurs between when the SRS is transmitted for self-interference/isolation estimation and when preparing and transmitting the report to the network as compared with a simple L1-RSRP measurement with SSB or CSI-RS sent from the base station and received at the UE with pre-informed BS Tx beam and UE receive (Rx) beam. One reason for this is that while sending from one transmit panel with a transmit beam, the UE may have turned on multiple receive panels with different receive beams, of which the UE needs to select one out of multiple receive panels/beams. To allow sufficient time to the UE, in some embodiments, the minimum delay between SRS transmission and associated report and/or that between triggering DCI and associated report may be restricted to be larger than those for conventional L1-RSRP or L1-SINR reporting. Since these parameter values may be reported as part of the UE capability, the minimum UE capability or the candidate values configured for DCI down-selection, or both, are expected to be larger than those for L1-RSRP or L1-SINR reporting. This possible implementation is illustrated inFIG.10, where the variables Z31010and Z3′1020are representative of minimum numbers of OFDM symbols between a last symbol of a physical downlink control channel (PDCCH) carrying a triggering DCI and a first symbol of an L1-RSRP report for a corresponding SSB or CSI-RS and between a last symbol of the SSB or CSI-RS and a first symbol of a corresponding L1-RSRP report, respectively. The variables Z41030and Z4′1040are representative of minimum numbers of OFDM symbols between a last symbol of a PDCCH carrying a triggering DCI and a first symbol of a self-interference/isolation report for SRS and between a last symbol of the SRS for self-interference/isolation estimation and a first symbol of a corresponding self-interference/isolation report, respectively. For a given subcarrier spacing (SCS) (indicated by a value of p1050), a value of Z4and Z4′ for self-interference/isolation estimation are expected to larger than the values are Z3and Z3′ for DL L1-RSRP reporting, respectively. Additionally, for a given SCS (indicated by a value of p), the value of Z4is expected to be larger than a minimum required processing time between a last symbol of a PDCCH carrying a triggering DCI and a first symbol of an SRS triggered for other purposes, such as UL and/or DL CSI acquisition. The variables Z1, Z1′, Z2, and Z2′ are minimum required delays for different types of CSI measurement and are not related to this disclosure. The variables X0-X3and KB1and KB2, can be found in Section 5.4 of 3GPP Technical Specification 38.214 (version g20).

While the set of candidate beams are described above as being based on measurement at the UE for CSI-RS received on a plurality of beams from the UE, in some embodiments, the set of candidate beams are based on measurement at the UE of positioning reference signals (PRS) received on a plurality of beams at the UE or tracking reference signals (TRS) received on a plurality of beams at the UE. While the set of candidate beams are described above as being based on measurement at the base station of SRS transmitted on a plurality of beams from the UE, in some embodiments, the set of candidate beams are based on measurement at the base station of PUCCH transmitted on a plurality of beams from the UE or random access channel (RACH) transmitted on a plurality of beams from the UE.

By the base station providing a candidate beam set to the UE, it is considered that beams that are not suitable for communicating with the BS will be precluded, thereby avoiding additional latency and resource consumption that may occur from exhaustive beam pair searching by the UE itself.

In some embodiments, by allowing the UE to select and report one or more possible UE transmit and UE receive beam pairs for FD transmission and corresponding self-interference/isolation levels, it is possible that the UE transmit and UE receive beam pairs at the UE that are not suitable for FD transmission will be deprioritized. Furthermore, the UE transmit and UE receive beam pairs that provide less self-interference, or better self-isolation, may be prioritized and tested within a first few measurement opportunities. In some embodiments, this may lead to a further reduction in latency and improved resource utilization.

Several methods of enabling cross-UE interference measurement between UEs to facilitate multi-UE transmission pairing for a group of UEs or for a group of at least one UE and at least one non-FD capable UEs will now be discussed.

In the context of multi-UE FD transmission, if the UE is given the opportunity to select and report the transmit and receive beam pair based on the SRS transmission for self-interference/isolation estimation and report to the base station at some later time, the measurement of cross-UE interference may become uncertain. This is because the base station cannot effectively coordinate beam selection at multiple UEs and the UEs are also unaware of beamforming behavior at neighbor UEs. As disclosed below, several possible methods are provided for assisting UE beamforming for cross-UE interference measurement by introducing information sharing among neighbor UEs via one or more of sidelink, dedicated UE reporting to the base station, or additional UE reporting to the base station.

In one embodiment, a method of enabling cross-UE interference measurement involves, for each SRS being transmitted for self-interference/isolation estimation, the UE shares by sidelink transmission the selected base station transmit beam. In some embodiments, selection of the base station transmit beam implies an associated receive beam of the UE sharing the information with the other UE for receiving the SRS. Detailed configuration information of SRS transmission for self-interference/isolation estimation for the UE sending the information can either be shared with neighbor UEs directly, or alternatively be informed to neighbor UEs in the form of SRS for cross-UE interference measurement. From such SRS configuration information, neighbor UEs can measure cross-UE interference, with an receive beam that is determined based on information shared by the UE sending the information.

Two schemes are described below involving selecting the UE receive beam at neighbor UEs when receiving the SRS. The first possibility is to choose the one that is suitable for DL reception with a same base station transmit beam. This would enable the base station to perform multi-UE FD transmission with the same base station transmit beam towards the UEs. The second possibility is to select the UE receive beam that can be used to receive from a base station transmit beam that is spatially distant from the base station transmit beam whose identity was shared by the UE. This would enable the base station to use spatially distant transmit beams to perform multi-UE transmission towards those UEs, assuming multiple antenna panels are available at the base station. The selected base station transmit beam can be represented by an SSB index and CSI-RS index, assuming the same CSI-RS resources are configured for these UEs. For the UE to determine the spatial distance between the two base station beams, the corresponding Euclidean distance after the SSB or CSI-RS indices are transformed into 2-dimensional Euclidean coordinates (by e.g., mod by maximum number of beams at one dimension) can be considered. The choice of these two possible schemes can be configured by the base station, or can be determined by the UE and potentially reported by the UE to the base station or neighbor UEs or shared by the UE with neighbor UEs.

Referring toFIG.11, an example of the method will now be described. The arrangement ofFIG.11includes a base station1110, a first UE, UE #1, illustrated to have at least two antenna panels that can transmit multiple beams and a second UE, UE #2that has at least one antenna panel that is shown to be used for receiving on multiple beams. UL beam pair1122between UE #1transmit beam1130aand base station receive beam1120a, UL beam pair1124between UE #1transmit beam1130band base station receive beam1120b, DL beam pair1142between base station transmit beam1140aand UE #1receive beam1150a, and DL beam pair1144between base station transmit beam1140band UE #1receive beam1150bmay have been determined during previous UL/DL beam pair training for half duplex transmissions. UE #1determines1162a UE transmit and UE receive pair (1130aand1150b) for FD with acceptable self-interference/self-isolation. This may be performed in the manner described above. UE #1then shares1164the base station transmit beam1140bfor possible FD. When UE #1transmits an SRS to determine whether there is acceptable self-interference/self-isolation between UE #1transmit beam1130aand UE #1receive beam1150b, UE #2can determine1166a cross-interference estimation between UE #1transmit beam1130aand UE #2receive beam1160. When UE #2selects a receive beam, UE #2can report1170that selection to the base station1110.

Another method of enabling cross-UE interference measurement in one embodiment involves, for each SRS being transmitted for self-interference/isolation estimation, the UE shares by sidelink transmission information on the selected UE transmit beam. Detailed configuration of SRS transmission for self-interference/isolation estimation for this UE can be either shared with neighbor UEs directly, or alternatively be informed to neighbor UEs in the form of SRS for cross-UE interference measurement. The UE transmit beam information can be based on previous beam training in sidelink transmissions between UEs. For example, if the UE has performed sidelink beam training by sending multiple SRS, the SRS index of the respective SRS can then be used to represent the UE transmit beam.

From SRS for self-interference/isolation estimation, or alternatively SRS for cross-UE interference measurement, neighbor UEs can measure cross-UE interference, with a receive beam that avoids strong interference between UEs, by exploiting channel knowledge obtained from previous sidelink beam training. Additionally, the receive beam selected by neighbor UEs may still need to be restricted to the candidate beam set configured by the base station, so to ensure proper DL reception from the base station. Using a restricted set of candidate beams is generally consistent with previously described embodiments in this disclosure.

Referring toFIG.12, an example of the method will now be described. The arrangement ofFIG.12includes a base station1210, a first UE, UE #1, illustrated to have at least two antenna panels that can transmit multiple beams and a second UE, UE #2that has at least one antenna panel that is shown to be used for receiving on multiple beams. UL #1has UE #1transmit beam1230a, UE #1transmit beam1230b, UE #1receive beam1250aand UE #1receive beam1250b. UL #2has UE #2receive beam1260. Base station1210has base station transmit beam1240a, base station transmit beam1240b, base station receive beam1220a, and base station receive beam1220b.

UE #1determines1262a transmit and receive pair (1230aand1250b) for FD with acceptable self-interference/isolation. This may be performed in the manner described above. UE #1then shares1264the base station transmit beam for possible FD. As part of sidelink beam training between UE #1and UE #2, UE #1transmits1266one or more SRS. UE #2is then able to select a receive beam that avoids interference from UE #1from among the SRS used for sidelink training while suitable for DL reception, i.e. selected from a set of candidate beams provided by the base station1210. When UE #2selects a receive beam, UE #2can report1270that selection to the base station1210.

The cross-UE interference measured at neighbor UEs, and the corresponding receive beam information, are reported to the base station, so as to facilitate the base station to decide whether and how to pair multiple UEs for multi-UE FD transmission. For one UE, the UE will be configured with SRS for self-interference/isolation estimation and SRS for cross-UE interference measurement. The latter can also be SRS for self-interference/isolation estimation for other UEs. The association between SRS for self-interference/isolation estimation and SRS for cross-UE interference measurement can be pre-defined, configured by the base station, or selected and reported by the UE.

In a scenario in which the association between the SRS for self-interference/isolation estimation and SRS for cross-UE interference measurement is pre-defined or configured by the base station (e.g., a one-to-one mapping between a particular SRS #1, #2or #3for self-isolation and a particular SRS #A, #B and #0for cross interference, respectively, as shown inFIG.13A), in one report for SRS for self-interference/isolation estimation, a selected SRS, transmit and receive beam, and measured self-interference/isolation may be included. In some embodiments, the UE may be configured to additionally report measured cross-UE interference that is measured from the associated SRS for cross-UE interference measurement, assuming that the UE receive beam selected and reported for the SRS for self-interference/isolation estimation is also used for receiving associated the SRS for cross-UE interference measurement.

When the association between the SRS for self-interference/isolation estimation and the SRS for cross-UE interference measurement are not configured, in one report for the SRS for self-interference/isolation estimation, the selected SRS, transmit and receive beam, and measured self-interference/isolation may be included. The base station may additionally configure the UE to report selected SRS for cross-UE interference measurement (as shown inFIG.13B), possibly based on the transmit beam information for SRS for cross-UE interference measurement shared from neighbor UEs. For example, exploiting previous sidelink beam training results, the UE can select the SRS for cross-UE interference measurement, such that under the selected UE receive beam the resulting cross-UE interference from neighbor UE is relatively small.

In some embodiments, introducing information sharing via sidelink, i.e., sharing the selected base station transmit beam or UE transmit beam for each SRS for self-interference/isolation estimation, or both, the beam selection at multiple UEs can be better coordinated for the purpose of multi-UE FD transmission. This can potentially increase the success rate of multi-UE FD transmission and lower the latency.

In some embodiments, introducing pre-defined, configured or a reported association between the SRS for self-interference/isolation estimation and the SRS for cross-UE interference measurement, it is possible to improve the interference measurement assumption including UE receive beamforming between the base station and the UEs being served by the base station, which may lead to an improved efficiency for multi-user FD transmissions.

FIGS.14to17will now be used to describe several examples of signal flow diagrams that enable selection of transmit and receive beams pairs for FD transmission schemes and multi-UE FD transmission schemes.

FIG.14is an example signaling flow diagram1400to illustrate steps that may be involved in determining transmit and receive beam pairs for FD transmissions between a base station1410and a UE1420based on DL beam measurements. Step1430involves the base station1410transmitting configuration information to the UE1420to enable the UE1420to perform measurements on reference signals transmitted by the base station1410. The configuration information includes information that notifies the UE1420about the reference signals, for example transmission resource information, reference signal index information, scrambling information for sequence generation, transmission timing and/or power, report content and/or format and/or timing, uplink resource for carrying report information. The reference signals may be channel state information reference signals (CSI-RS). Step1440involves the base station1410transmitting the reference signals to the UE1420. Step1450involves the UE1420performing DL beam reporting with a particular set of CSI-RS resources (this may include a set of identifiers such as CSI-RS resources #1, #3, #5and #7) representing selected base station transmit beam and associated UE receive beam. Step1460involves, based on the information reported to the base station1410in step1450, the base station1410providing the UE1420configuration information about a reference signal the UE1420can use for self-interference/isolation estimation based on using a set of candidate beams. Referring to the set of CSI-RS resources indicated above, the set of candidate beams may include CSI-RS resources #1, #3, and #5from that larger set. The reference signal may be a sounding reference signal (SRS). This may be based on beam correspondence at the UE1420with the base station1410. Step1470involves the UE selecting UE transmit and UE receive beams from the candidate set in order to perform self-interference/isolation estimation. This may involve prioritizing the candidate sets to test in a particular order. Step1480involves the UE transmitting and receiving the reference signal in order to obtain the measurements for self-interference/isolation estimation. Step1490involves the UE reporting information about the reference signal that was used in performing the self-interference/isolation estimation, the selected UE transmit and UE receive beams and the measurement of the self-interference/isolation estimation.

FIG.15is an example signaling flow diagram1500to illustrate steps that may be involved in determining transmit and receive beam pairs for FD transmissions between a base station1510and a UE1520based on UL beam measurements. Step1530involves the base station1510transmitting configuration information to the UE1520to enable the UE1520to transmit reference signals to be measured by the base station1510. The configuration information includes information that notifies the UE1520about the reference signals it is to use for example transmission resource information, reference signal index information, transmission timing, scrambling information for sequence generation. The reference signals may be SRS. Step1540involves the UE1520transmitting the reference signals, which may for example be SRS, to the base station1510. In a particular example the reference signals may include SRS resources #1to SRS #8. Step1550involves, based on the signal received by the base station1510in step1540, the base station1510providing the UE1520configuration information about a reference signal the UE1520can use for self-interference/isolation estimation based on using a set of candidate beams. Referring to the set of SRS resources indicated above, the set of candidate beams may include SRS resources #1, #3, and #5. This may be based on beam correspondence at the UE1420with the base station1410. Step1560involves the UE selecting UE transmit and UE receive beams from the candidate set in order to perform self-interference/isolation estimation. This may involve prioritizing the candidate sets to test in a particular order. Step1570involves the UE transmitting and receiving the reference signal in order to obtain the measurements for self-interference/isolation estimation. Step1580involves the UE reporting information about the reference signal that was used in performing the self-interference/isolation estimation, the selected transmit and receive beams and the measurement of the self-interference/isolation estimation.

In some embodiments, the steps shown in bothFIGS.14and15may be performed such that DL and UL beam measurement are both performed. The base station sends CSI-RS and the UE sends SRS, the base station determines two sets of candidate beams for the UE to choose from, one set of candidate DL receive beams based on DL beam measurements and one set of candidate UL transmit beams based on UL beam measurements, and then the UE performs self-interference/isolation estimation, selects one or more beam candidates, and then reports the beam selection back to the base station.

FIG.16is an example signaling flow diagram1600to illustrate steps that may be involved in determining transmit and receive beam pairs for FD transmissions between a base station1610and multiple UEs1620,1625based on DL beam measurements and using SL transmission between the UEs. Steps1630to1670are substantially the same as steps1430to1470ofFIG.14. Step1675involves the UE #11620transmitting an indication of the base station transmit beam to UE #21625. Step1680involves the UE #11620transmitting and receiving the reference signal in order to obtain the measurements for self-interference/isolation estimation. Step1685involves UE #21625, when selecting the UE #2receive beam for DL measurement or for self-interference/isolation estimation, prioritizing beams of a candidate beam set that can received from the base station transmit beam that was shared by UE #11620. Step1690involves the UE #11620reporting information about the reference signal that was used in performing the self-interference/isolation estimation, the selected transmit and receive beams and the measurement of the self-interference/isolation estimation.

FIG.17is an example signaling flow diagram1700to illustrate steps that may be involved in determining transmit and receive beam pairs for FD transmissions between a base station1710and multiple UEs1720,1725based on DL beam measurements and using SL transmission between the UEs. Steps1730to1770are substantially the same as steps1430to1470ofFIG.14. Step1775involves the UE #11720transmitting an indication of the UE #1transmit beam to be used for self-interference/isolation at UE #11720to UE #21725. Step1780involves the UE #11720transmitting and receiving the reference signal in order to obtain the measurements for self-interference/isolation estimation. Step1785involves UE #21725, when selecting the UE #2receive beam for DL measurement or for self-interference/isolation estimation, avoiding candidate beams that receive a strong signal from the UE #1transmit beam to be used for self-interference/isolation at UE #11720shared by UE #11720. Step1790involves the UE #11720reporting information about the reference signal that was used in performing the self-interference/isolation estimation, the selected transmit and receive beams and the measurement of the self-interference/isolation estimation.

In some embodiments, beam related information that is provided by a base station to a UE (e.g., the beam related information used to represent candidate beams at a UE for the UE select and pair for FD transmission) can be alternatively expressed in the form of angle(s) and/or range(s) of angle(s) that the UE can be beamforming to receive a signal from or transmit a signal towards. The beamforming may consist of switching among multiple UE panels or steering the beamforming on a given UE panel, or both. The angle(s) and/or range(s) of angle(s) can be expressed in global coordination systems (e.g., using the sun or the earth as reference) or in local coordination systems (e.g., using a facing direction of the UE as reference). The angle(s) and/or range(s) of angle(s) can also be expressed as a relative difference to a previous angle that the UE was beamforming towards at a previous time instance. The beam related information that is reported from a UE to a base station (e.g., one transmit beam and one receive beam at a UE that the UE has paired, measured, and observed with high self-isolation and/or low self-interference for FD transmission) and that can be shared by one UE with another (e.g., a BS transmit beam that is being used to communicate with the one UE) can be expressed in a similar manner. Instead of exact angles, the angular domains covered by a base station or a UE can alternatively be divided into several sectors (with potential overlapping), and the beam-related information mentioned above can alternatively be expressed in the form of sector numbers, representing an angular range that the UE can be beamforming to receive from or transmit towards. It is also possible the beam related information further contains desired beamforming gain(s) and/or emitted power(s) towards certain angle(s) and/or accumulated energy towards certain sector(s). As an alternative, the beam related information can be expressed in the form of angles and sectors that the UE should try to minimize energy emission during beamforming.

The base station mentioned in this invention, while generally described as being a terrestrial base station, can also be considered to be a satellite, or a vehicle, or a balloon or a high-altitude pseudo-satellite (HAPS) carrying a base station or a UE. The UE mentioned in this invention, while generally described as being a terrestrial UE, can also be considered to be a satellite, or a vehicle, or a balloon or a high-altitude pseudo-satellite (HAPS) carrying a base station or a UE.

It should be appreciated that one or more steps 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. 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). It will be appreciated that where the modules are software, they may be retrieved by a processor, in whole or part as needed, individually or together for processing, in single or multiple instances as required, and that the modules themselves may include instructions for further deployment and instantiation.