Patent Description:
The link quality between the UE and the base station can be degraded due to several factors, such as loss in signal strength, interfering signals, and so forth. For example, a downlink or uplink of a UE can cause co-channel interference in another communication link of another UE. Several solutions have been developed to improve link quality.

Document <CIT> discloses a system and a method for Interference Cancellation Using Terminal Cooperation. According to <CIT>, soft information for achieving interference cancellation in downlink transmissions can be communicated over device-to-device (D2D) links, thereby allowing paired user equipments (UEs) to receive downlink transmissions over the same radio resources. Paired UEs that receive transmissions over the same time-frequency resources may exchange soft or hard information over D2D links in order to facilitate interference cancellation. Paired UEs may be in the same or different cells, and may receive their respective transmissions from the same or different transmit point. UEs may be paired with one another based on various criteria, e.g., interference cancellation capabilities, scheduling metrics, etc.

However, with recent advancements in wireless communication systems, such as Fifth Generation New Radio (<NUM> NR), new approaches may be available.

This document describes techniques and apparatuses of user equipment coordination for co-channel interference mitigation. In some aspects, the techniques enable base stations to form user equipment-coordination sets (UE-coordination sets) in which user equipment of the UE-coordination set can share or exchange signal-related information to enable interference cancelation. The apparatuses and techniques described in this document overcome challenges that a UE may encounter when a downlink transmission to another UE interferes with a reception by the UE of signals transmitted to the UE by a base station. For example, such interference may prevent the UE from being able to receive a downlink from the base station or impair demodulation and decoding of the downlink by the UE.

The details of one or more implementations of user equipment coordination for co-channel interference mitigation are set forth in the accompanying drawings and the following description.

The details of one or more aspects of user equipment coordination for co-channel interference mitigation are described below. The use of the same reference numbers in different instances in the description and the figures indicate similar elements:.

In conventional wireless communication systems, a radio frequency (RF) signal quality (link quality) between a user equipment (UE) and a base station (BS) can degrade due to several factors, including signal interference, UE movement relative to the base station, or obstructions between the UE and the base station. This signal quality degradation may result in slower and less efficient data transmissions.

A type of interference, which may be referred to as "co-channel interference," can occur when a first UE uses a set of air interface resources for a downlink with a first base station at the same time a second UE uses at least a subset or portion of those same air interface resources for a downlink with a second base station. Co-channel interference (CCI) can be particularly strong for UEs of neighboring or adjacent base stations (or network cells), such as when UEs of different base stations that are proximate to each other and are near coverage boundaries of their respective base stations.

This document describes aspects of user equipment coordination for co-channel interference mitigation, which may be implemented to form a user equipment-coordination set (UE-coordination set, UECS) between multiple UEs. Generally, the user equipment-coordination set includes at least two UEs that communicate through a local wireless network connection, such as to perform joint transmission, joint reception and/or share other signal-related or schedule-related information. For example, the aforementioned first UE and second UE can be grouped into a UECS and employ joint reception to mitigate the effects of co-channel interference when the first UE and the second UE are concurrently receiving downlink communications from their respective serving base stations.

Joint communication by the UE-coordination set enhances a target UE's ability to transmit data to a base station and receive data from the base station by generally acting as a distributed antenna of the target UE. For example, the base station transmits downlink data using radio frequency (RF) signals to multiple UEs in the UE-coordination set. At least some of the multiple UEs demodulate the received RF signals to an analog baseband signal and sample the baseband signal to produce a set of I/Q samples, which the UEs send to a coordinating UE along with system timing information. The coordinating UE accumulates and stores the I/Q samples from each UE in a memory buffer. Because each of the UEs in the UE-coordination set synchronizes with the base station, all of the UEs in the UE-coordination set have a common time, based on a common time base (e.g., system frame number (SFN)), effective to enable the coordinating UE to manage the timing and aligning of the I/Q samples for the accumulation and storage of the I/Q samples in the memory buffer. For joint reception and decoding, the coordinating UE processes the stored I/Q samples to decode the downlink data for the target UE (which may be the coordinating UE or any other UE in the UECS). In aspects, I/Q samples can be processed at multiple UEs (e.g., less than all the UEs in the UE-coordination set), at the target UE or at the coordinating UE. At least a subset of the UEs in the UE-coordination set can participate in the accumulation and/or the joint processing of the downlink I/Q samples. In at least one aspect, the coordinating UE can select which UEs in the UE-coordination set are to be included in the subset of UEs that participate in the accumulation and/or the joint processing of the downlink I/Q samples. In other aspects, the base station can make this selection. For joint transmission, multiple UEs in the UE-coordination set each use their respective antennas and transmitters to transmit uplink data from the target UE on air interface resources as directed by the base station coordinating the UE-coordination set. In this way, the target UE's uplink data can be processed together and transmitted using the transmitters and the transmission antennas of multiple (including all) UEs in the UE-coordination set. In an example, the target UE uses its local wireless network transceiver to transmit uplink data to the coordinating UE. The coordinating UE uses its local wireless network transceiver to distribute the data to the other UEs in the UE-coordination set. Then, all the UEs in the UE-coordination set process and transmit the uplink data to the base station. In this way, the joint transmission provides for a better effective link budget for transmission of the uplink data for the target UE.

In aspects of user equipment coordination for co-channel interference mitigation, the first UE of the UE-coordination set can receive, from the second UE of the UE-coordination set and through a local wireless network connection, I/Q samples (e.g., in-phase and quadrature amplitude modulation (I/Q) samples) of downlink signals received by the second UE from the second base station during a same time interval during which the first UE received downlink signals from the first base station. The information provided by the second UE may include signal-related information describing signals of the second downlink transmission (e.g., in-phase and quadrature amplitude modulation (I/Q) samples) or scheduling information describing how or when the second downlink transmission occurs (e.g., time, frequency, and/or modulation coding scheme (MCS) information). Based on the received I/Q samples, the first UE can model interference from the second downlink transmission of the second base station to a reception of a first downlink transmission from the first base station by the first UE. After the first UE receives the first downlink transmission, the first UE cancels, based on the modeling of the interference, the interference to the first downlink transmission from the second downlink transmission of the second base station. By so doing, the first UE can reduce or cancel the co-channel interference caused by the second downlink transmission from the second base station to the received first downlink signals intended for the first UE, thereby improving receive performance or communication link quality of the first UE. Likewise, joint reception, interference modeling, and interference cancelation can be used to mitigate interference to the second downlink to the second UE from the first downlink transmissions by the first base station to the first UE.

<FIG> illustrates an example operating environment <NUM> in which various aspects of user equipment coordination for co-channel interference mitigation can be implemented. Generally, the example environment <NUM> includes multiple user equipment <NUM> (UE <NUM>), illustrated as UE <NUM>, UE <NUM>, and UE <NUM> of a UE-coordination set. Each UE <NUM> can communicate with base stations <NUM> (illustrated as base stations <NUM>, <NUM>, <NUM>, and <NUM>) through wireless communication links <NUM> (wireless link <NUM>), illustrated as wireless links <NUM> and <NUM>. Each UE <NUM> in a UE-coordination set can communicate with other UE <NUM> in the UE-coordination set through one or more local wireless network connections which are illustrated in this example as local wireless network connections <NUM>, <NUM>, and <NUM>. The local wireless network connections can be implemented as any suitable type of wireless connection or link, such as a millimeter wave (mmWave) link, sub-millimeter wave (sub-mmWave) link, free space optical (FSO) link, wireless local access network (WLAN), wireless personal area network (WPAN), near-field communication (NFC), Bluetooth™, ZigBee™, radar, lidar, sonar, ultrasonic, or the like.

In some aspects, the base stations <NUM> provide configuration information to the UEs <NUM> to establish or manage the local wireless network connections. Alternately or additionally, the local wireless network connections <NUM>, <NUM>, or <NUM> can be configured to use an unlicensed frequency band. In such cases, the UEs <NUM> may coordinate to establish the local wireless network connections. In some aspects, the UEs <NUM> communicate over the local wireless network connections <NUM>, <NUM>, or <NUM> to share signal-related information or scheduling information associated with an uplink communication of one of the UEs <NUM>. For simplicity, the UE <NUM> is implemented as a smartphone but may be implemented as any suitable computing or electronic device, such as a smart watch, mobile communication device, modem, cellular phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, smart appliance, vehicle-based communication system, an Internet-of things (IoT) device (e.g., sensor node, controller/actuator node, combination thereof), and the like. The base stations <NUM> (e.g., an Evolved Universal Terrestrial Radio Access Network Node B, E-UTRAN Node B, evolved Node B, eNodeB, eNB, Next Generation Node B, gNode B, gNB, or the like) may be implemented in a macrocell, microcell, small cell, picocell, or the like, or any combination thereof.

The base stations <NUM> communicate with the UE <NUM> through the wireless links <NUM> and <NUM>, which may be implemented as any suitable type of wireless link. The wireless links <NUM> and <NUM> include control and data communication, such as downlink of data and control information communicated from the base stations <NUM> to the UE <NUM>, uplink of other data and control information communicated from the UE <NUM> to the base stations <NUM>, or both. The wireless links <NUM> may include one or more wireless links (e.g., radio links) or bearers implemented using any suitable communication protocol or standard, or combination of communication protocols or standards, such as 3rd Generation Partnership Project Long-Term Evolution (3GPP LTE), Fifth Generation New Radio (5GNR), and so forth. Multiple wireless links <NUM> may be aggregated in a carrier aggregation to provide a higher data rate for the UE <NUM>. Multiple wireless links <NUM> from multiple base stations <NUM> may be configured for Coordinated Multipoint (CoMP) communication with the UE <NUM>. Additionally, multiple wireless links <NUM> may be configured for single-RAT dual connectivity or multi-RAT dual connectivity (MR-DC). Each of these various multiple-link situations tends to increase the power consumption of the UE <NUM>.

The base stations <NUM> collectively form a Radio Access Network <NUM> (e.g., RAN, Evolved Universal Terrestrial Radio Access Network, E-UTRAN, <NUM> NR RAN or NR RAN). The RANs <NUM> are illustrated as an NR RAN <NUM> and an E-UTRAN <NUM>. The base stations <NUM> and <NUM> in the NR RAN <NUM> are connected to a Fifth Generation Core <NUM> (5GC <NUM>) network. The base stations <NUM> and <NUM> in the E-UTRAN <NUM> connect to an Evolved Packet Core <NUM> (EPC <NUM>). Alternately or additionally, the base station <NUM> may connect to both the 5GC <NUM> and EPC <NUM> networks.

The base stations <NUM> and <NUM> connect, at <NUM> and <NUM> respectively, to the 5GC <NUM> through an NG2 interface for control-plane signaling and using an NG3 interface for user-plane data communications. The base stations <NUM> and <NUM> connect, at <NUM> and <NUM> respectively, to the EPC <NUM> using an S <NUM> interface for control-plane signaling and user-plane data communications. Optionally or additionally, if the base station <NUM> connects to the 5GC <NUM> and EPC <NUM> networks, the base station <NUM> connects to the 5GC <NUM> using an NG2 interface for control-plane signaling and through an NG3 interface for user-plane data communications, at <NUM>.

In addition to connections to core networks, the base stations <NUM> may communicate with each other. For example, the base stations <NUM> and <NUM> communicate through an Xn interface at <NUM> and the base stations <NUM> and <NUM> communicate through an X2 interface at <NUM> to exchange user-plane and control-plane data. The interface or link at <NUM> or <NUM> between the base stations <NUM> can be implemented as any suitable type of link, such as a mmWave link, a sub-mmWave link, or an FSO link. At least one base station <NUM> (base station <NUM> and/or base station <NUM>) in the NR RAN <NUM> can communicate with at least one base station <NUM> (base station <NUM> and/or base station <NUM>) in the E-UTRAN <NUM> using an Xn interface <NUM>. In aspects, base stations <NUM> in different RANs (e.g., master base stations <NUM> of each RAN) communicate with one another using an Xn interface such as Xn interface <NUM>.

The 5GC <NUM> includes an Access and Mobility Management Function <NUM> (AMF <NUM>), which provides control-plane functions, such as registration and authentication of multiple UE <NUM>, authorization, and mobility management in the <NUM> NR network. The EPC <NUM> includes a Mobility Management Entity <NUM> (MME <NUM>), which provides control-plane functions, such as registration and authentication of multiple UE <NUM>, authorization, or mobility management in the E-UTRA network. The AMF <NUM> and the MME <NUM> communicate with the base stations <NUM> in the RANs <NUM> and also communicate with multiple UE <NUM>, using the base stations <NUM>.

<FIG> illustrates an example device diagram <NUM> of a user equipment and a service cell base station. Generally, the device diagram <NUM> describes network entities that can implement various aspects of UE coordination for interference cancelation. <FIG> shows respective instances of the multiple UEs <NUM> and the base stations <NUM>. The multiple UEs <NUM> and the base stations <NUM> may include additional functions and interfaces that are omitted from <FIG> for the sake visual brevity. The UE <NUM> includes antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), and radio-frequency transceivers (e.g., an LTE transceiver <NUM> and a <NUM> NR transceiver <NUM>) for communicating with base stations <NUM> in the <NUM> RAN <NUM> and/or the E-UTRAN <NUM>. The UE <NUM> includes one or more additional transceivers (e.g., local wireless network transceiver <NUM>) for communicating over one or more local wireless networks (e.g., WLAN, WPAN, Bluetooth™, NFC, Wi-Fi-Direct, IEEE <NUM>. <NUM>, ZigBee, Thread, mmWave, sub-mmWave, FSO, radar, lidar, sonar, ultrasonic) with at least one other UE of the UE-coordination set. The RF front end <NUM> of the UE <NUM> can couple or connect the LTE transceiver <NUM>, the <NUM> NR transceiver <NUM>, and the local wireless network transceiver <NUM> to the antennas <NUM> to facilitate various types of wireless communication.

The antennas <NUM> of the UE <NUM> may include an array of multiple antennas that are configured similar to or differently from each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined by the 3GPP LTE and <NUM> NR communication standards and implemented by the LTE transceiver <NUM>, and/or the <NUM> NR transceiver <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, the LTE transceiver <NUM>, and/or the <NUM> NR transceiver <NUM> may be configured to support beamforming for the transmission and reception of communications with the base stations <NUM>. By way of example and not limitation, the antennas <NUM> and the RF front end <NUM> can be implemented for operation in sub-gigahertz bands, sub-<NUM> bands, and/or above <NUM> bands that are defined by the 3GPP LTE and <NUM> NR communication standards (e.g., <NUM>-<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> bands). In addition, the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined and implemented by the local wireless network transceiver <NUM> to support transmission and reception of communications with other UEs in the UE-coordination set over a local wireless network.

The UE <NUM> includes sensor(s) <NUM> can be implemented to detect various properties such as temperature, supplied power, power usage, battery state, or the like. As such, the sensors <NUM> may include any one or a combination of temperature sensors, thermistors, battery sensors, and power usage sensors.

The UE <NUM> also includes processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> may be a single core processor or a multiple core processor implemented with a homogenous or heterogenous core structure. The computer-readable storage media described herein excludes propagating signals. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the UE <NUM>. The device data <NUM> includes user data, multimedia data, beamforming codebooks, applications, and/or an operating system of the UE <NUM>, which are executable by processor(s) <NUM> to enable user-plane communication, control-plane signaling, and user interaction with the UE <NUM>.

In aspects of user equipment coordination, the CRM <NUM> of the UE <NUM> may also include an interference canceler <NUM> (an interference canceler application <NUM>), scheduling information <NUM>, and I/Q samples <NUM>. Alternately or additionally, the interference canceler <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the UE <NUM>. Generally, the interference canceler <NUM> of the UE <NUM> can cancel or reduce interference to a first downlink transmission to the UE caused by or associated with a second downlink transmission to another UE <NUM>. To do so, the interference canceler <NUM> according to the claimed invention receives scheduling information <NUM> and signal-related information, such as I/Q samples <NUM>, for the second downlink transmission to the other UE. The I/Q (in-phase and quadrature amplitude modulation) samples <NUM> or data can be indicative of signal characteristics (amplitude, phase, etc.) of at least part of a transmission. Scheduling information or data indicates, according to the claimed invention, MIMO (Multiple Input Multiple Output) modes and modulation modes at different points in time. The scheduling data may indicate precise timing of transmissions, including transmissions that have occurred in the past, as well as future transmissions that have yet to occur.

Based on the signal-related information, the interference canceler <NUM> can model, reconstruct, or estimate interference from the other downlink transmission to reception of the first downlink transmission to the UE <NUM> by a first base station. The interference canceler <NUM> can use the modeling of the interference to cancel the co-channel interference to the received first downlink transmission from the second downlink transmission.

The interference canceler <NUM> can reduce or cancel interference in a variety of ways or procedures. In some aspects, modeled interference or reconstructed interference is subtracted from signals of the downlink at an I/Q level. Alternately or additionally, the interference canceler <NUM> can generate a filter based on the I/Q samples <NUM> and apply the generated filter to the signals of the downlink to cancel the interference. By so doing, the interference canceler <NUM> can reduce co-channel interference caused by the second downlink transmission to the other UE <NUM> and improve receive performance of the UE <NUM>. To communicate with another UE <NUM>, the interference canceler <NUM> may also establish or configure a local wireless network connection with the other UE <NUM> to communicate or share the signal-related information. The implementations and uses of the interference canceler <NUM> vary and are described throughout the disclosure.

Aspects and functionalities of the UE <NUM> may be managed by operating system controls presented through an application programming interface (API). In some aspects, the interference canceler <NUM> accesses an API or an API service of the UE <NUM> to control aspects and functionalities of the user equipment or transceivers thereof. For example, the interference canceler <NUM> can access or utilize the LTE transceiver <NUM> or <NUM> NR transceiver <NUM> to model interference based on the I/Q samples <NUM>, generate filters using the I/Q samples, or to subtract the modeled interference from received signals at the I/Q level. CRM <NUM> also includes a communication manager (not shown). The communication manager may also be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the UE <NUM>. In at least some aspects, the communication manager configures the RF front end <NUM>, the LTE transceiver <NUM>, the <NUM> NR transceiver <NUM>, and/or the local wireless network transceiver <NUM> to implement the techniques of user equipment coordination for co-channel interference mitigation as described herein.

The device diagram for the base stations <NUM>, shown in <FIG>, includes a single network node (e.g., a gNode B). The functionality of the base stations <NUM> may be distributed across multiple network nodes or devices and may be distributed in any fashion suitable to perform the functions described herein. The base stations <NUM> include antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), one or more LTE transceivers <NUM>, and/or one or more <NUM> NR transceivers <NUM> for communicating with the UE <NUM>. The RF front end <NUM> of the base stations <NUM> can couple or connect the LTE transceivers <NUM> and the <NUM> NR transceivers <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> of the base stations <NUM> may include an array of multiple antennas that are configured similar to or differently from each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency band defined by the 3GPP LTE and <NUM> NR communication standards, and implemented by the LTE transceivers <NUM>, and/or the <NUM> NR transceivers <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, the LTE transceivers <NUM>, and/or the <NUM> NR transceivers <NUM> may be configured to support beamforming, such as Massive-MIMO, for the transmission and reception of communications with any UE <NUM> in a UE-coordination set.

The base stations <NUM> also include processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the base stations <NUM>. The device data <NUM> includes network scheduling data, radio resource management data, beamforming codebooks, applications, and/or an operating system of the base stations <NUM>, which are executable by processor(s) <NUM> to enable communication with the UE <NUM>.

In aspects, the CRM <NUM> of the base station <NUM> also includes a user equipment set coordinator <NUM> (coordinator <NUM>, user equipment set coordinator application <NUM>) and scheduling information <NUM>. Alternately or additionally, the coordinator <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the base station <NUM>. The scheduling information <NUM> can be used to setup a downlink transmission to a UE <NUM> or provided to another UE <NUM> to assist with interference cancelation.

Generally, the coordinator <NUM> enables the base station <NUM> to coordinate with other base stations <NUM> to form UE-coordination sets for interference cancelation. For example, the base station <NUM> may pair, select, or group UEs that are configured to use same time and frequency resources (e.g., candidates for interference cancelation). Alternately or additionally, the base station <NUM> or coordinator <NUM> may select UEs <NUM> that are close to each and/or near a respective edge of cell coverage provided by the base stations <NUM>. In some cases, the coordinator <NUM> accounts for or considers mutual interference between the base stations <NUM> when determining which UEs <NUM> of the respective cells to group for the UE-coordination set.

The coordinator <NUM> of the base station <NUM> may also enable or configure a local wireless network connection between the UEs <NUM> of the UE-coordination set, such as to facilitate sharing of signal-based information or scheduling information <NUM> of a downlink transmission. For example, the coordinator <NUM> may allocate resources of a local wireless network connection that is available to both UEs <NUM> of the UE-coordination set and then provide an indication of the allocated resources to at least one of the UEs <NUM>. By so doing, the UEs can establish the local wireless network connection for sharing information (e.g., I/Q samples) to enable interference cancelation.

CRM <NUM> also includes a base station manager <NUM>. Alternately or additionally, the base station manager <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the base stations <NUM>. In at least some aspects, the base station manager <NUM> configures the LTE transceivers <NUM> and the <NUM> NR transceivers <NUM> for communication with the UE <NUM>, as well as communication with a core network. The base stations <NUM> include an inter-base station interface <NUM>, such as an Xn and/or X2 interface, which the base station manager <NUM> configures to exchange user-plane and control-plane data between another base station <NUM>, to manage the communication of the base stations <NUM> with the UE <NUM>. The base stations <NUM> include a core network interface <NUM> that the base station manager <NUM> configures to exchange user-plane and control-plane data with core network functions and/or entities.

<FIG> illustrates an air interface resource that extends between a user equipment and a base station and with which various aspects of a UE-coordination set for a wireless network using an unlicensed frequency band can be implemented. In aspects, base stations <NUM> may determine that UEs <NUM> have respective air interface resources that intersect such that co-channel interference may occur. As such, the base stations <NUM> may form a UE-coordination set to enable one of the UEs to cancel potential interference caused by another base station or another UE of the UE-coordination set. The air interface resource <NUM> can be divided into resource units <NUM>, each of which occupies some intersection of frequency spectrum and elapsed time. A portion of the air interface resource <NUM> is illustrated graphically in a grid or matrix having multiple resource blocks <NUM>, including example resource blocks <NUM>, <NUM>, <NUM>, <NUM>. An example of a resource unit <NUM> therefore includes at least one resource block <NUM>. As shown, time is depicted along the horizontal dimension as the abscissa axis, and frequency is depicted along the vertical dimension as the ordinate axis. The air interface resource <NUM>, as defined by a given communication protocol or standard, may span any suitable specified frequency range, and/or may be divided into intervals of any specified duration. Increments of time can correspond to, for example, milliseconds (mSec). Increments of frequency can correspond to, for example, megahertz (MHz).

In example operations generally, the base stations <NUM> allocate portions (e.g., resource units <NUM>) of the air interface resource <NUM> for uplink and downlink communications. Each resource block <NUM> of network access resources may be allocated to support respective wireless communication links <NUM> of multiple user equipment <NUM>. In the lower left corner of the grid, the resource block <NUM> may span, as defined by a given communication protocol, a specified frequency range <NUM> and comprise multiple subcarriers or frequency sub-bands. The resource block <NUM> may include any suitable number of subcarriers (e.g., <NUM>) that each correspond to a respective portion (e.g., <NUM>) of the specified frequency range <NUM> (e.g., <NUM>). The resource block <NUM> may also span, as defined by the given communication protocol, a specified time interval <NUM> or time slot (e.g., lasting approximately one-half millisecond or <NUM> orthogonal frequency-division multiplexing (OFDM) symbols). The time interval <NUM> includes subintervals that may each correspond to a symbol, such as an OFDM symbol. As shown in <FIG>, each resource block <NUM> may include multiple resource elements <NUM> (REs) that correspond to, or are defined by, a subcarrier of the frequency range <NUM> and a subinterval (or symbol) of the time interval <NUM>. Alternatively, a given resource element <NUM> may span more than one frequency subcarrier or symbol. Thus, a resource unit <NUM> may include at least one resource block <NUM>, at least one resource element <NUM>, and so forth.

In example implementations, multiple user equipment <NUM> (one of which is shown) are communicating with the base stations <NUM> (one of which is shown) through access provided by portions of the air interface resource <NUM>. The base station manager <NUM> (shown in <FIG>) may determine a respective data-rate, type of information, or amount of information (e.g., data or control information) to be communicated (e.g., transmitted) by the user equipment <NUM>. For example, the base station manager <NUM> can determine that each user equipment <NUM> is to transmit at a different respective data rate or transmit a different respective amount of information. The base station manager <NUM> then allocates one or more resource blocks <NUM> to each user equipment <NUM> based on the determined data rate or amount of information.

Additionally, or in the alternative to block-level resource grants, the base station manager <NUM> may allocate resource units at an element-level. Thus, the base station manager <NUM> may allocate one or more resource elements <NUM> or individual subcarriers to different user equipment <NUM>. By so doing, one resource block <NUM> can be allocated to facilitate network access for multiple user equipment <NUM>. Accordingly, the base station manager <NUM> may allocate, at various granularities, one or up to all subcarriers or resource elements <NUM> of a resource block <NUM> to one user equipment <NUM> or divided across multiple user equipment <NUM>, thereby enabling higher network utilization or increased spectrum efficiency.

The base station manager <NUM> can therefore allocate air interface resource <NUM> by resource unit <NUM>, resource block <NUM>, frequency carrier, time interval, resource element <NUM>, frequency subcarrier, time subinterval, symbol, spreading code, some combination thereof, and so forth. Based on respective allocations of resource units <NUM>, the base station manager <NUM> can transmit respective messages to the multiple user equipment <NUM> indicating the respective allocation of resource units <NUM> to each user equipment <NUM>. Each message may enable a respective user equipment <NUM> to queue the information or configure the LTE transceiver <NUM>, and/or the <NUM> NR transceiver <NUM>, to communicate via the allocated resource units <NUM> of the air interface resource <NUM>.

<FIG> illustrates an example environment at <NUM> in which a user equipment-coordination set <NUM> is implemented in accordance with one or more aspects. In this example, connection with a radio access network is provided by base stations <NUM> and <NUM>, each of which manages respective UEs. In this example, assume that base station <NUM> manages UE <NUM> and base station <NUM> manages UE <NUM> of the user equipment-coordination set <NUM>. By way of review, co-channel interference can occur when the base station <NUM> and the UE <NUM> use a first set of time and frequency air interface resources for a first downlink at the same time the base station <NUM> and the UE <NUM> use at least a subset or portion of the first set of time and frequency air interface resources for a second downlink. Depending on the air interface resource allocations (time and frequency) of downlinks to each UE, co-channel interference may affect UE <NUM> at certain times and affect UE <NUM> at other times. Co-channel interference may also be more likely to occur when UEs <NUM> of neighboring or adjacent base stations (or network areas) are proximate to each other as shown in <FIG>.

In aspects of user equipment coordination for co-channel interference mitigation, a coordinator <NUM> of the base stations <NUM> can group UEs <NUM> into a UE-coordination set <NUM> to address co-channel interference. For example, the coordinator <NUM> can determine that two of the UEs <NUM> have scheduled air interface resources that intersect (collide) such that co-channel interference may occur. The coordinator <NUM> may also account for mutual interference between the base stations <NUM> and <NUM> when determining which UEs <NUM> to group for the UE-coordination set <NUM>. Alternately or additionally, a coordinator <NUM> of the base stations <NUM> may analyze a respective signal strength, transmit power, mobility state, power capability, or geographic location of the UEs <NUM> when determining which UEs to group for the UE-coordination set <NUM>.

The base stations <NUM> and <NUM>, can group UEs into UECSs for interference mitigation either statically or dynamically. For static grouping, the base stations <NUM> and <NUM> determine groups of UEs <NUM> in advance, based on UE locations, but directing the UEs to coordinate occurs once the base stations <NUM> and <NUM> determine that there are scheduled, colliding air interface resources within one of the predetermined groups. For dynamic grouping, the base stations <NUM> and <NUM> form a UECS after colliding resource scheduling between two base stations is detected. Dynamic grouping may additionally consider the geographic locations of the UEs with colliding resource schedules.

In an alternative aspect, the base station <NUM> may have formed a first UECS that includes multiple UEs that are served by the base station <NUM> and the base station <NUM> may have formed a second UECS that includes multiple UEs that are served by the base station <NUM>. The first UECS and the second UECS operate independently with their respective serving base stations when there is no need to coordinate to mitigate co-channel interference. If the base station <NUM> and the base station <NUM> determine that there are colliding air interface schedules between some of the UEs in the first UECS and the second UECS, the base stations <NUM> and <NUM> can direct those UEs in the first UECS and the second UECS to coordinate to mitigate co-channel interference.

As part of the UE-coordination set <NUM>, the coordinator <NUM> or base stations <NUM> may allocate resources of a local wireless network connection <NUM> that is available to the UE <NUM> and the UE <NUM>. In some cases, this enables the UEs <NUM> to share signal-related information and/or scheduling information associated with downlinks to the UEs <NUM> from their respective base stations <NUM>. Based on this information, an interference canceler <NUM> of the UE <NUM> can use joint reception to model, reconstruct, or estimate interference from the downlink from the base station <NUM> to a reception of a downlink transmission from the base station <NUM> to the UE <NUM>. Using the modeled interference, the interference canceler <NUM> can cancel or reduce interference to downlink reception by the UE <NUM>. Likewise, joint reception can be used to model, reconstruct, or estimate interference from the downlink from the base station <NUM> to a reception of a downlink transmission from the base station <NUM> to the UE <NUM>. By so doing, receiver performance of the interference-canceling UE can be improved for downlink reception, and interference-limiting of network capacity is reduced.

With reference to <FIG>, an example of this is illustrated by UEs <NUM> and <NUM> which are configured as a UE-coordination set <NUM> by the base stations <NUM>. Here, assume that UE <NUM> transmits, over local wireless network connection <NUM>, I/Q samples of a downlink transmission <NUM> from the base station <NUM>. The UE <NUM> may also receive additional information (e.g., a Modulation and Coding Scheme, timing information, or the like) for the downlink <NUM> from the UE <NUM> through the local wireless network connection <NUM> or from the base station <NUM> through another downlink (e.g., relayed from base station <NUM> via a base station interface, such as an Xn interface).

To cancel the interference <NUM> to the downlink <NUM>, the interference canceler <NUM> models, based on the I/Q samples, the interference caused by or associated with the downlink <NUM> to the UE <NUM>. The interference canceler <NUM> then subtracts the modeled interference from the received signals to cancel at least a portion of the interference <NUM> to the downlink <NUM> received from the base station <NUM>. In some cases, the interference canceler <NUM> reduces or cancels the interference at an I/Q signal level based on the modeled interference. After the interference is removed from the received downlink signals, the downlink signals can be demodulated and decoded for data or other control information of the downlink from the base station <NUM>.

<FIG> illustrates an example of transactions among various network entities in accordance with aspects of user equipment coordination for co-channel interference mitigation. The base stations <NUM> and <NUM> and the UEs <NUM> and <NUM> may be implemented similar to the entities described with reference to <FIG>. Generally, the transactions of <FIG> are described in the context of the environment of <FIG> in which a first UE <NUM> and a second UE <NUM> may experience co-channel interference to downlink communications from respective base stations <NUM> and <NUM>. As such, the base station <NUM> and base station <NUM> may form a UE-coordination set <NUM> that enables the UE <NUM> and the UE <NUM> to reduce or cancel the interference that occurs during reception of a downlink transmissions from the base stations <NUM> and <NUM>.

At <NUM>, the base station <NUM> and base station <NUM> perform scheduling coordination, such as to determine which UEs of their respective cells, UE-coordination sets, or coverage areas to group for user equipment coordination. The base stations <NUM> and <NUM> may pair, select, or group UEs that are configured to use overlapping time and frequency resources when the interference cancelation is enabled between the UEs. For example, the base station <NUM> and the base station <NUM> may determine that the UE <NUM> and the UE <NUM> are scheduled to use colliding air interface resources. As a result of the determination, the base station <NUM> and the base station <NUM> direct the UE <NUM> and the UE <NUM> to form a UECS in order to coordinate to reduce co-channel interference.

In some cases, the base station <NUM> and <NUM> account for or consider mutual interference between the base stations when determining which UEs to group for the UE-coordination set. The base stations <NUM> may also analyze a respective signal strength, transmit power, mobility state, power capability, or geographic location of UEs when determining which UEs to group for the UE-coordination set.

At <NUM>, the base station <NUM> transmits a control channel message to the UE <NUM> that instructs the UE <NUM> to coordinate with the UE <NUM>. The control channel message may include the identity of the UE(s) in the UECS (e.g., the identity of the UE <NUM>) and/or a data channel grant including related information, such as an MCS, channel information, timing information, or frequency information. At <NUM>, the base station <NUM> transmits a control channel message to the UE <NUM> that instructs the UE <NUM> to coordinate with the UE <NUM>. The control channel message may include the identity of the UE(s) in the UECS (e.g., the identity of the UE <NUM>), a data channel grant including related information, such as an MCS, channel information, timing information, or frequency information. The base stations <NUM> and <NUM> can account for the time required for the UE <NUM> and the UE <NUM> to form the UECS (e.g., establish the local wireless connection <NUM>) by transmitting the control channel messages sufficiently in advance of the use of the data channel grants for downlink communication.

In some aspects, the base stations <NUM> send layer-<NUM> messages (e.g., Media Access Control layer) and/or layer-<NUM> (e.g., Service Data Adaptation Protocol layer) messages to UEs <NUM> to direct or request those UEs to join the UE-coordination set <NUM>. The base stations <NUM> can provide additional data to the UEs <NUM> within the UE-coordination set to enable the UEs to communicate directly with other UEs of the UE-coordination set. The additional data may include an identity of a coordinating UE for the UE-coordination set, security information, and/or local wireless network information.

In one aspect, the base station <NUM> and the base station <NUM> can adapt the scheduling of the UE <NUM> and the UE <NUM> to increase the amount of colliding air interface resources used in the downlinks to the UE <NUM> and the UE <NUM>. By exploiting the joint reception capabilities of the UECS to differentiate between desired and undesired signals after demodulation, increasing the amount of colliding air interface resources enables the base stations <NUM> and <NUM> to increase overall spectral efficiency.

Optionally or additionally at <NUM>, the UEs in the UECS can share grant scheduling information for each UE through a local wireless network connection. For example, the UEs can share scheduling information such as bandwidth parts, resource block allocation, slot/OFDM symbol allocation, MIMO layers, and the like, to support the UECS differentiating downlink communications on a per-UE basis.

At <NUM>, the UE <NUM> receives a first downlink transmission from the base station <NUM> during transmission of the second downlink transmission from the base station <NUM>. At <NUM>, the UE <NUM> receives the second downlink transmission from the base station <NUM> during transmission of the first downlink transmission from the base station <NUM>. At <NUM>, the UE <NUM> also receives the second downlink transmission from the base station <NUM> as co-channel interference to the first downlink transmission from the base station <NUM>.

At <NUM>, after demodulating the second downlink transmission from the base station <NUM>, the UE <NUM> transmits, through the local wireless network connection, I/Q samples of the demodulated downlink signals to the UE <NUM>.

At <NUM>, the UE <NUM> models, based on the I/Q samples, interference caused by the second downlink transmission from the base station <NUM> at <NUM>. For example, the UE <NUM> may model the interference based on additional signaling information, such as timing information, frequency information, or MCS information received from the UE <NUM> or through the base station <NUM> (e.g., provided by the base station <NUM>) at <NUM>.

At <NUM>, based on the modeled interference, the UE <NUM> cancels the interference to the received first downlink transmission caused by the second downlink transmission of the base station <NUM>. In some cases, the UE <NUM> reduces or cancels the interference at an I/Q signal level based on the modeled interference. For example, the UE <NUM> may subtract the modeled or estimated interference from demodulated receive signals of the downlink that are affected by the co-channel interference. Alternately or additionally, the UE <NUM> may apply a filter generated using the I/Q data for the second downlink to the signals of the received first downlink transmission to cancel the interference.

At <NUM>, the UE <NUM> demodulates the received downlink signals from which the interference is canceled. By canceling or reducing the interference caused by the co-channel interference, receive performance of the UE <NUM> can be improved. At <NUM>, the UE <NUM> decodes, from the demodulated downlink, data or control information transmitted by the base station <NUM> to the UE <NUM>. In some cases, mitigating the co-channel interference from the downlink is effective to improve decoding performance of the UE <NUM> or reduces a number of retransmissions needed to enable successful data decoding operations.

In one alternative (not illustrated in <FIG>), the UE <NUM> can use the I/Q samples received at <NUM> to demodulate the second downlink in a manner similar to the process illustrated in <NUM>, <NUM>, and <NUM> by modeling and mitigating the co-channel interference from the first downlink to the second downlink. In another alternative (not illustrated in <FIG>), after demodulating the first downlink transmission from the base station <NUM>, the UE <NUM> transmits, through the local wireless network connection, I/Q samples of the demodulated downlink signals to the UE <NUM>. The UE <NUM> uses the received I/Q samples from the UE <NUM> to demodulate the second downlink in a manner similar to the process illustrated in <NUM>, <NUM>, and <NUM> by modeling and mitigating the co-channel interference from the first downlink to the second downlink. The decision of where to perform interference mitigation and demodulation may vary in each UECS based on the capabilities of the UEs in each UECS, latency demands of the applications executing on the UEs, or the like.

Example methods <NUM> and <NUM> are described with reference to <FIG> and <FIG> in accordance with one or more aspects of user equipment coordination for co-channel interference mitigation. The order in which the method blocks are described are not intended to be construed as a limitation, and any number of the described method blocks can be skipped or combined in any order to implement a method or an alternate method. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods may be described in the general context of executable instructions stored on computer-readable storage memory that is local and/or remote to a computer processing system, and implementations can include software applications, programs, functions, and the like. Alternatively, or additionally, any of the functionality described herein can be performed, at least in part, by one or more hardware logic components, such as, and without limitation, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

<FIG> illustrates an example method for canceling interference from a received downlink transmission. In some aspects, operations of the method <NUM> are implemented by an interference canceler <NUM> of a UE <NUM>. Alternately or additionally, the operations of the method <NUM> can be implemented by other entities described herein, such as by UEs <NUM> of a UE-coordination set <NUM>.

At <NUM>, a first UE (e.g., the UE <NUM>) establishes a local wireless network connection (e.g., the local wireless connection <NUM>) with a second UE (e.g., the UE <NUM>). The first UE is managed by a first base station (e.g., the base station <NUM>) of a wireless network, and the second UE is managed by a second base station (e.g., the base station <NUM>) of the wireless network. The local wireless network connection established between the first UE and the second UE may include a millimeter wave link, a sub-millimeter wave link, a free space optical link, or a wireless local access network link. The local wireless network connection between the first UE and the second UE can be implemented in a licensed frequency band or an unlicensed frequency band. In some cases, the first UE receives, from the first base station, information useful to configure the local wireless network connection with the second UE. In other cases, the first UE may determine or generate the information useful to configure the local wireless network connection. This information may include or indicate a type of the local wireless network connection, the frequency band of the local wireless network connection, frequency resources of the local wireless network connection, or time resources of the local wireless network connection.

At <NUM>, the first UE receives a first downlink transmission from the first base station. For example, the UE <NUM> receives a data channel downlink transmission from the base station <NUM>. At <NUM>, the first UE may also receive interference caused by the second downlink transmission of the second base station to the second UE.

At <NUM>, the first UE receives second information describing signals of the second downlink transmission from the second base station to the second UE. The second information includes I/Q samples, quadrature signals, or other information associated with the second downlink transmission. Alternately or additionally, the second information may include time resources, frequency resources, and/or a modulation coding scheme (MCS) of the second downlink transmission.

At <NUM>, the first UE models, based on the second information, interference to the received first downlink transmission from the second downlink transmission of the second base station. This interference may be caused by or associated with the scheduled downlink transmission of the second base station. For example, the first UE may model, reconstruct, or estimate the interference cause by the second downlink based on I/Q samples received from the second UE. In some cases, the first UE generates, using the I/Q samples, a filter for canceling the interference from a reception of a downlink transmission. Alternately or additionally, the first UE can model the interference based on additional signaling information, such as timing information, frequency information, or MCS information received from the second UE or relayed through the first base station (e.g., provided by the second base station). In some cases, the first UE uses a non-Gaussian interference estimation calculation to model the interference based on the second information.

At <NUM>, the first UE cancels, based on the modeled interference, the interference to the received first downlink transmission from the second downlink transmission. In some cases, the first UE reduces or cancels the interference at an I/Q signal level based on the modeled interference. For example, the first UE may subtract the modeled or estimated interference from demodulated receive signals of the first downlink that are affected by the co-channel interference. Alternately or additionally, the first UE may apply the generated filter to the received signals of the first downlink transmission to cancel the interference.

At <NUM>, the first UE demodulates the received first downlink from which at least a portion of the interference is canceled or reduced. Alternately or additionally, the received first downlink may be demodulated before or during interference cancelation operations. By canceling or reducing at least a portion of the interference caused by the second downlink transmission, receive performance of the first UE can be improved. At <NUM>, the first UE decodes, from the demodulated downlink, data or control information transmitted by the first base station to the first UE.

<FIG> illustrates an example method for forming a user equipment-coordination set in accordance with one or more aspects. In some implementations, operations of the method <NUM> are performed by a coordinator <NUM> of a base station <NUM>. Alternately or additionally, the operations of the method <NUM> can be implemented by other entities described herein, such as the base stations <NUM>.

At <NUM>, a first base station allocates resources of an air interface to a first UE of a first cell managed by the first base station. The first base station may allocate the resources or configure the first base station as part of managing the first base station or in association with handover operations when the first base station enters a network cell managed by the first base station. In some cases, the first base station collects or determines information regarding multiple UEs associated with or being managed by the first base station, such as UEs that are connected to, or registered with, the first base station. This information may include a respective signal strength, transmit power, mobility state, power capability, local wireless network connection capability, UE-coordination set capability (e.g., interference cancelation capabilities), or location of UEs in a cell of the first base station.

At <NUM>, the first base station receives information from a second base station regarding UEs of a second cell managed by the second base station, such as UEs that are connected to, or registered with, the second base station. The first base station and second base station may communicate over an Xn interface, such as an Xn interface implemented through a wireline link. The information provided by the second base station may include a respective signal strength, transmit power, mobility state, power capability, local wireless network connection capability, UE-coordination set capability, or location of the UEs of the second cell.

At <NUM>, the first base station assigns, based on the information, the first UE of the first cell and a second UE of the second cell to a UE-coordination set. This operation may be performed in coordination with the second base station. For example, the first base station or base stations may pair, select, or group UEs that are configured to use same time and frequency resources. Alternately or additionally, the base stations may select UEs that are close to each and/or near a respective edge of cell coverage provided by the base stations. In some cases, the base stations account for or consider mutual interference between the base stations when determining which UEs of the respective cells to pair up for the UE-coordination set. Alternately or additionally, one of base stations may analyze a respective signal strength, transmit power, mobility state, power capability, or location of UEs when determining which UEs to pair for the UE-coordination set. In some aspects, the first base station transmits a message or indication to the first UE to assign the first UE to the UE-coordination set. For example, the first base station can transmit a layer-<NUM> message and/or layer-<NUM> message to the first UE to direct or request that first UE to join the UE-coordination formed by the first base station.

At <NUM>, the first base station allocates resources of a local wireless network connection available to the first UE and second UE. This allows the first UE and the second UE to share signal-related information or schedule-related information that may be used by one of the UEs for interference cancelation. Generally, the first UE and the second UE are configured to communicate directly over the local wireless network connection, though information may be provided or relayed through a respective base station to a UE. The local wireless network connection can include a millimeter wave link, a sub-millimeter wave link, a free space optical link, or a wireless local access network link.

At <NUM>, the first base station transmits an indication of the allocated resources of the local wireless network connection to the first UE. In some cases, the first base station also transmits the indication to the second base station, which then relays the indication to the second UE. Thus, the first base station may use the second base station to relay the indication to the second UE that is not directly managed by the first base station. Providing the indication to the first UE and the second UE of the UE-coordination set enables the UEs to communicate or share information for implementing interference cancelation. The indication transmitted to the UEs may indicate a type of the local wireless network connection, frequency band of the local wireless network connection, frequency resources of the local wireless network connection, or time resources of the local wireless network connection.

Optionally at <NUM>, the first base station transmits additional downlink-related information to the first UE. The additional information may include scheduling information for downlink transmission of the second base station to the second UE. Alternately, the second UE can transmit the scheduling information to the first UE, such as over the local wireless network connection between the UEs.

Claim 1:
A method performed by a first user equipment to cancel co-channel interference in coordination with a second user equipment, the method comprising the first user equipment:
receiving (<NUM>) a first downlink transmission from a first base station;
receiving (<NUM>), from the second user equipment, first information regarding a second downlink transmission from a second base station to the second user equipment, the first information including I/Q samples of the second downlink transmission as demodulated;
receiving second information from the first base station regarding scheduling of the second downlink transmission, the second information indicating Multiple Input Multiple Output modes and modulation modes at different points in time;
based on the received first information and second information, modeling (<NUM>) interference from the second downlink transmission to the reception of the first downlink transmission at the first user equipment; and
based on the modeling of the interference, canceling (<NUM>) the co-channel interference to the received first downlink transmission from the second downlink transmission.