WO2023115058A2

WO2023115058A2 - Adaptive phase-changing devices for active coordination sets

Info

Publication number: WO2023115058A2
Application number: PCT/US2022/081918
Authority: WO
Inventors: Jibing Wang; Erik Richard Stauffer
Original assignee: Google Llc
Priority date: 2021-12-17
Filing date: 2022-12-19
Publication date: 2023-06-22
Also published as: WO2023115058A3

Abstract

Various techniques as described herein coordinate one or more adaptive phase-changing devices, APDs, for communicating with a user equipment, UE. A base station receives (715) a request from a UE to add an additional base station to an active coordination set, ACS, that communicates with the UE using multiple base stations for joint communications. The base station selects (735) selecting a surface configuration for a surface of an APD included in a first communication path between the UE and the first base station or a second communication path between the UE and the additional base station and directs (740) the APD to apply the surface configuration to the surface of the APD. The base station then communicates (745) with the UE as part of the ACS by performing the joint communications with the UE using the APD in the first communication path or the second communication path.

Description

ADAPTIVE PHASE-CHANGING DEVICES FOR ACTIVE COORDINATION SETS

BACKGROUND

[0001] Evolving wireless communication systems, such as fifth generation (5G) technologies and sixth generation (6G) technologies, use various techniques that increase data capacity relative to preceding wireless networks. As one example, 5G and 6G systems support various forms of wireless connectivity that use multiple radio links between base stations and a user equipment (UE) to increase data rates, throughput, and reliability of the wireless network. To illustrate, dual connectivity or coordinated multipoint communications can improve the operating performance (e.g., data rates, throughput, reliability) of the wireless network especially when received signal strengths decrease for the user equipment near the edge of a cell.

[0002] While these forms of coordinated communications improve the performance of the communication exchanges (e.g., improved data rates, improved throughput, improved reliability), a dynamically changing operating environment can diminish these improvements. To illustrate, consider a scenario in which a first base station and a second base station establish coordinated multipoint communications with a UE. Over time, the UE may move out of range of the first and/or second base station to a location with decreased coordinated multipoint communication efficacy. In such a scenario, conventional mobility management techniques use handovers (or other types of node changes) to maintain connectivity for the UE and/or connect the UE to a different base station with a stronger signal. These handovers disconnect radio bearers for a source base station and establish new bearers for a target base station, which sometimes results in interrupted data communication for the UE, reduced data throughput, and/or increased data latency. Higher frequency ranges used by evolving wireless communication systems can help increase data capacity but pose challenges for transmitting and recovering information. The higher-frequency signals, for example, are more susceptible to multipath fading and other types of path loss, which leads to recovery errors at a receiver, reduces data throughput, and/or increases data transfer latency. With recent technological advancements, new approaches may be available to mitigate interrupted data communications and/or improve the performance of wireless communications.

SUMMARY

[0003] This document describes techniques and apparatuses for adaptive phase-changing devices (APDs) for an active coordination set (ACS). A first base station receives a request from a user equipment (UE) to add or maintain a second base station in an ACS that jointly communicates with the UE using multiple base stations. The first base station selects a surface configuration for a surface of an APD included in a communication path between the UE and the second base station. The base station directs the APD to apply the surface configuration to the surface of the APD and communicates with the UE as part of the ACS by performing the joint communications with the UE, where the joint communications use the APD in the communication path. For example, a UE may detect an impairment or decrease in signal quality of the joint communications related to the second base station (e.g., due to UE movement, a dynamic signal blocker, or changing weather conditions) and may request the first base station to add the APD to the communication path or adjust the surface configuration of the APD to maintain the joint communications or preclude a handover to another base station. This is but one example of how an APD may be used to enable and/or maintain joint communications between base stations in an ACS with the UE.

[0004] According to a further aspect of the invention there is provided an apparatus comprising a wireless transceiver, a processor, and computer-readable storage media comprising instructions that, responsive to execution by the processor, direct the apparatus to perform a method or operations as recited above. According to a still further aspect of the invention there is provided computer-readable storage media comprising instructions that, responsive to execution by a processor, direct an apparatus to perform a method as recited above.

[0005] The details of one or more implementations for APDs for an ACS are set forth in the accompanying drawings and the following description. Other features and advantages will be apparent from the description, the drawings, and the claims. This summary is provided to introduce subject matter that is further described in the Detailed Description and Drawings. Accordingly, this summary should not be considered to describe essential features nor used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The details of one or more aspects for adaptive phase-changing devices (APDs) for an active coordination set (ACS) are described with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components:

FIG. 1 illustrates an example operating environment that can be used to implement various aspects of APDs for an ACS;

FIG. 2 illustrates an example device diagram of entities that can implement various aspects of APDs for an ACS;

FIG. 3 illustrates an example device diagram of an adaptive phase-changing device that can be used in accordance with one or more aspects of APDs for an ACS; FIG. 4 illustrates an example environment in which a base station configures an adaptive phase-changing device in accordance with various aspects of APDs for an ACS;

FIG. 5 illustrates an example environment that can be used to implement various aspects of APDs for an ACS;

FIG. 6 illustrates an example environment that can be used to implement various aspects of APDs for an ACS;

FIG. 7 illustrates an example transaction diagram between various network entities in accordance with various aspects of APDs for an ACS;

FIG. 8 illustrates an example transaction diagram between various network entities in accordance with various aspects of APDs for an ACS; and

FIG. 9 illustrates an example method in accordance with various aspects of multi-UE- communication transmissions using APDs.

DETAILED DESCRIPTION

[0007] Techniques such as dual connectivity or coordinated multipoint communications can improve the operating performance (e.g., data rates, throughput, reliability) of a wireless network and the services provided to a user equipment (UE) operating in the wireless network. While these forms of coordinated communications help the performance of the communication exchanges (e.g., improved data rates, improved throughput, improved reliability), conventional mobility management techniques may interrupt data communication by using handovers to maintain connectivity with the UE, such as when the UE moves to the edge of a first cell and/or into a coverage area of a second cell. The interruptions to the data communications can diminish data rates and throughput.

[0008] An active coordination set (ACS) has a set of base stations (e.g., 5G and/or 6G base stations) that are determined by a user equipment (UE) for joint wireless communications between the UE and the set of base stations. More specifically, the set of base stations in the ACS perform joint transmission and/or joint reception of communications with the UE. As one example, the set of base stations participating in the ACS transmit a same signal, sometimes using time alignment, time shifts, and/or phase shifts in the respective signals, to improve received signal strength at the UE. As another example, the set of base stations may transmit different Multiple Input, Multiple Output (MIMO) layers to the UE (e.g., a first base station transmits a first MIMO layer to the UE, a second base station transmits a second MIMO layer to the UE) to increase data throughput.

[0009] As described with reference to FIG. 5, the base stations participating in the ACS may change as the UE moves locations. To illustrate, as the UE changes location, the UE identifies that a first received signal from a first base station not participating in the ACS meets or exceeds a performance threshold value, and that a second received signal from a second base station participating in the ACS fails to meet the performance threshold. The UE requests, from a coordinating base station of the ACS, a modification to the ACS to add the first base station as a participant and to remove the second base station as a participant. The coordinating base station then manages these changes without disruption to the joint communications. Thus, an ACS helps avoid the potential interruptions that occur in conventional techniques, such as a handover which disconnects a first radio bearer and establishes a second radio bearer.

[0010] An ACS may also improve performance by communicating with the UE using high-frequency signals above the 6-Gigahertz (GHz) range (e.g., mmWave signals). For example, transmissions in these frequency ranges can increase data throughput and/or decrease data transfer latency when operating under line-of-sight (LoS) conditions. These higher frequency signals, however, are more susceptible to multipath fading, blockage by obstructions, and/or attenuation by obstructions, which leads to recovery errors at a receiver, reduces data throughput, and/or increases data transfer latency.

[0011] Adaptive phase-changing devices (APDs) include a Reconfigurable Intelligent Surface (RIS) that, when properly configured, modifies propagating signals to correct for, or reduce, errors introduced by communication path(s), such as small-scale fading and fading MIMO channels. Generally, an RIS includes configurable surface materials that shape how incident signals striking the surface of the materials are transformed and reflected. To illustrate, the configuration of the surface materials can affect the phase, amplitude, spatial coverage area, and/or polarization of the transformed signal. Thus, modifying a surface configuration of the RIS changes how incident signals are transformed when they reflect off the RIS.

[0012] In aspects of APDs for an ACS, a base station receives a request from a user equipment (UE) to add an additional base station to an ACS that communicates with the UE using multiple base stations for joint communications. The base station selects a surface configuration for a surface of an APD included in a first communication path between the UE and the first base station or a second communication path between the UE and the additional base station. The base station directs the APD to apply the surface configuration to the surface of the APD and communicates with the UE as part of the ACS by performing the joint communications with the UE, where the joint communications use the APD in the first communication path or the second communication path.

[0013] As channel conditions change for a UE, the UE can reconfigure the APD(s) (e.g., alter a surface configuration) or add another APD to the ACS while concurrently communicating with base stations in the ACS. This allows a coordinating base station to reconfigure one or more of the APDs or add another APD to support the joint communication between the base stations and the UE, which can maintain the ACS base station set and/or preclude having to perform a handover to another base station that interrupts data communication. By so doing, the coordinating base station may maintain the data throughput for the UE on the ACS. Further, including APDs in the various ACS communication paths may allow the participating base stations to communicate with the UE using higher frequency ranges. For example, the APDs help to decrease destructive interference, improve constructive interference, and/or redirect reflective signals around LoS obstructions. This mitigates conditions that might otherwise cause recovery errors at a receiver, which improves data rates, data throughput, and reliability in a wireless network. As another example, a UE may detect an impairment or decrease in signal quality of the joint communications related to the second base station (e.g., due to UE movement, a dynamic signal blocker, or changing weather conditions) and may request the first base station to add the APD to the communication path between the UE and the second base station or adjust the surface configuration of the APD to maintain the j oint communications of the AC S or preclude a handover to another base station. These are but a few examples of how an APD may be used to enable and/or maintain joint communications between base stations in an ACS with the UE.

[0014] While features and concepts of the described systems and methods for APDs for an ACS can be implemented in any number of different environments, systems, devices, and/or various configurations, various aspects of APDs for an ACS are described in the context of the following example devices, systems, and configurations.

Example Environment

[0015] FIG. 1 illustrates an example environment 100, which includes a user equipment 110 (UE 110) jointly communicating with a set of base stations 120 (illustrated as base station 121 and base station 122) that are included in an active coordination set 160 (ACS 160) as further described with reference to FIGs. 5 and 6. For simplicity, the UE 110 is implemented as a smartphone but may be implemented as any suitable computing or electronic device, such as a mobile communication device, modem, cellular phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, smart appliance, vehicle-based communication system, or an Intemet-of-Things (loT) device, such as a sensor, relay, or actuator. The base stations 120 (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, ng- eNB, or the like) may be implemented in a macrocell, microcell, small cell, picocell, distributed base stations, or the like, or any combination thereof. [0016] The UE 110 jointly communicates with the base stations 121 and 122 through one or more wireless communication links 130 (wireless link 130). In the environment 100, the wireless link between the UE 110 and the base stations 121 and 122 is illustrated as wireless link 13E The wireless links 130 also include a wireless link 132 and a wireless link 133 that the base stations 120 use to communicate with one or more adaptive phase-changing devices (APDs), which are generally labeled in FIG. 1 as adaptive phase-changing device(s) 180 (APDs 180). To illustrate, the base station 121 communicates APD-control information (e.g., surface configuration, timing configurations, position configurations) to an APD 181 using the wireless link 132. In other implementations, the base station 121 includes a wireline interface for communicating the APD-control information to the APD 181. Similarly, the base station 122 communicates APD-control information to an APD 182 using the wireless link 133 or a wireline interface. However, a base station may alternatively or additionally communicate with multiple APDs (not shown in FIG. 1).

[0001] The base stations 120 communicate with the UE 110 using the wireless link 131, which may be implemented as any suitable type of wireless link. The wireless link 131 can include a downlink of user-plane data and/or control-plane information jointly transmitted by the base stations 120 in the ACS 160 to the UE 110, an uplink of other user-plane data and/or control-plane information communicated from the UE 110 and jointly received by the base stations 120 in the ACS 160, or both. The wireless links 130 may include one or more wireless 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), 6G, and so forth. As one example, the multiple wireless links can include a first sub-6 Gigahertz (GHz) anchor link and a second, above 6 GHz link. Multiple wireless links 130 may be aggregated in a carrier aggregation to provide a higher data rate for the UE 110. Multiple wireless links 130 from multiple base stations 120 may be configured for Coordinated Multipoint (CoMP) communication with the UE 110. Additionally, multiple wireless links 130 may be configured for single-radio access technology (RAT) (single-RAT) dual connectivity (single-RAT-DC) or multi-RAT dual connectivity (MR- DC).

[0017] In some implementations, the wireless links 130 utilize wireless signals that one or more intermediate devices (e.g., APD 180) reflect or transform, such as reflections that route the wireless signals around obstructions 170 that block line-of-sight (LoS) transmissions between the base stations 120 and the UE 110. The obstructions can range from a more-temporary obstruction such as fog or rain water vapor (shown) or a moving vehicle, to a seasonal obstruction such as deciduous trees (shown), to a more-permanent obstruction such as a building (shown). Other examples include ceilings, walls, office desks, people, cubicle partitions, indoor foliage, furniture, fixtures, monitors, and so forth, for indoor implementations. In aspects, the intermediate device(s) (e.g., the APD 180) alternatively or additionally spatially modify an incident wireless signal (e.g., widen, narrow), change a polarization of the incident wireless signal, and/or change a phase shift of the incident wireless signal.

[0018] To illustrate, the base station 121 uses the APD 181 to propagate ray(s) 190towards (and/or receive from) the UE 111, illustrated as signal ray 191, signal ray 192, and signal ray 193. In the environment 100, the signal ray 190 corresponds to individual rays of a narrow-beam or wide-beam (up to and including omnidirectional) wireless signal used to implement the wireless link 131, such as a downlink wireless signal (illustrated in FIG. 1) from the base station 121 to the UE 110 and/or an uplink wireless signal (not illustrated in FIG. 1) from the UE 110 to the base station 121. A first ray of the downlink wireless signal (e.g., the signal ray 191) propagates toward the UE 110 in a line-of-sight (LoS) manner, where an obstruction 170 dynamically blocks and/or attenuates the LoS signal ray 191. A second ray of the downlink wireless signal (e.g., the signal ray 192) propagates toward the APD 181. The second signal ray 192 strikes the surface of the APD 181 and transforms into a third signal ray 193 that propagates toward the UE 110. In a similar manner, and as part of the ACS 160 that implements the wireless link 131, the base station 122 jointly transmits a downlink wireless signal illustrated as signal ray 194, which strikes the surface of the APD 182 and transforms into signal ray 195 that propagates towards the UE 110.

[0019] The base station 120 can configure an RIS of the APD 180 to direct how the RIS alters signal properties (e.g., direction, phase, amplitude, spatial properties, and/or polarization) of a wireless signal. As one example, the base station 121 selects a first surface configuration for the APD 181 based on any combination of factors (e.g., UE location, signal-quality measurements, link-quality measurements, historical records) and communicates the surface configuration to the APD 181 using the wireless link 132. In some aspects, the base station 121 selects the first surface configuration using a beam-sweeping procedure as described with reference to FIGs. 7 and 8. The base station 121 may alternatively or additionally select a second configuration for the APD 182 and communicate the second configuration directly to the APD 182 (not shown in FIG. 1), or indirectly through the base station 122.

[0020] Generally, the wireless links 132 and 133 correspond to an adaptive phasechanging device-control channel (APD-control channel) that can be implemented using low-band wireless signals (e.g., using frequencies below 6 GHz) and/or high-band wireless signals (e.g., using frequencies above 6 GHz). The wireless links 132 and 133 may include an adaptive phasechanging device slow-control channel (APD-slow-control channel) for communicating large quantities of control data (e.g., codebooks) and/or an adaptive phase-changing device fast-control channel (APD-fast-control channel) for quickly communicating time-sensitive control information (e.g., apply a surface configuration at the start of the next time slot).

[0021] In various implementations of APDs for an ACS, the base station 120 determines surface configuration(s) for the APD 180 that direct or steer reflections of wireless signals between the base station 120 and the UE 110, such as through a beam-sweeping procedure. Alternatively or additionally, the base station 120 determines surface configuration(s) for the APD 180 based on location information, downlink signal-quality measurements/parameters received from the UE 110, uplink-quality measurements/parameters generated by the base station 120, and/or historical records regarding previous successful and unsuccessful uplink and/or downlink wireless communications including APD locations, UE locations, downlink/uplink (DL/UL) signal strength/quality measurement reports, messages, APD reconfigurable surface configurations (e.g., indices), APD reconfigurable surface configuration codebooks, and so forth. In aspects, the base station 120 selects a surface configuration that introduces a particular phase shift in the reflected signal, forms a particular transmit diversity pattern using the reflected signal, changes a polarization of the reflected signal, and so forth.

[0022] The base stations 120 collectively form at least part of a Radio Access Network 140 (RAN 140) (e.g., RAN, Evolved Universal Terrestrial Radio Access Network, E-UTRAN, 5GNR RAN or NR RAN). The base stations 121 and 122 connect, at 102 and 104 respectively, to a core network 150 through an NG2 interface for control-plane signaling and an NG3 interface for user-plane data communications when connecting to a 5G core network or using an SI interface for control-plane signaling and user-plane data communications when connecting to an Evolved Packet Core (EPC) network. The UE 110 may connect, via the RAN 140 and core network 150, to public networks (e.g., the Internet) to interact with a remote service (not illustrated in FIG. 1).

[0023] The base stations 121 and 122 can communicate using an Xn Application Protocol (XnAP) through an Xn interface or using an X2 Application Protocol (X2AP) through an X2 interface, at 106, to exchange user-plane and control-plane data. In some aspects, the base stations 121 and 122 exchange APD reconfigurable surface configurations as further described. Alternatively or additionally, the base stations 121 and 122 communicate with one another using a wireless integrated access backhaul (IAB) link (not illustrated in FIG. 1), where one of the base stations acts as a donor base station and the other base station acts as a node base station.

Example Devices

[0024] FIG. 2 illustrates an example device diagram 200 of the UE 110 and base station 120. Generally, the device diagram 200 describes network entities that can implement various aspects of APDs for an ACS. FIG. 2 shows respective instances of the UE 110 and the base station 120. The UE 110 or the base station 120 may include additional functions and interfaces that are omitted from FIG. 2 for the sake of visual brevity. The UE 110 includes antennas 202, a radio-frequency front end 204 (RF front end 204), and one or more wireless transceivers 206 (e.g., radio-frequency transceivers), such as any combination of an LTE transceiver, a 5G NR transceiver, and/ or a 6G transceiver for communicating with the base station 120 in the RAN 140. The RF front end 204 of the UE 110 can couple or connect the wireless transceivers 206 to the antennas 202 to facilitate various types of wireless communication.

[0025] The antennas 202 of the UE 110 may include an array of multiple antennas that are configured in a similar manner or different from each other. The antennas 202 and the RF front end 204 can be tuned to, and/or be tunable to, one or more frequency bands defined by communication standards (e.g., 3GPP LTE, 5G NR and/or 6G) and implemented by the wireless transceiver(s) 206. Additionally, the antennas 202, the RF front end 204, and/or the wireless transceiver(s) 206 may be configured to support beam-sweeping for the transmission and reception of communications with the base stations 120. By way of example and not limitation, the antennas 202 and the RF front end 204 can be implemented for operation in sub-gigahertz bands, sub-6 GHz bands, and/or above-6 GHz bands that are defined by the 3GPP LTE and 5G NR communication standards (e.g., 57-64 GHz, 28 GHz, 38 GHz, 71 GHz, 81 GHz, or 92 GHz bands).

[0026] The UE 110 also includes processor(s) 208 and computer-readable storage media 210 (CRM 210). The processor 208 may be a single-core processor or a multiple-core processor implemented with a homogenous or heterogeneous core structure. The computer-readable storage media described herein excludes propagating signals. CRM 210 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 212 of the UE 110. The device data 212 includes any combination of user data, multimedia data, applications, and/or an operating system of the UE 110. In implementations, the device data 212 stores processor-executable instructions that are executable by the processor(s) 208 to enable user-plane communication, control-plane signaling, and user interaction with the UE 110.

[0027] The CRM 210 of the UE 110 may optionally include a user equipment adaptive phase-changing device manager 214 (UE APD manager 214). Alternatively or additionally, the UE APD manager 214 may be implemented in whole or part as hardware logic or circuitry integrated with or separately from other components of the UE 110. In aspects, the UE APD manager 214 receives APD-access information for using a surface of an APD, such as reflection- access information that indicates time information on when to use the APD reconfigurable surface, configurable surface element information that indicates portions of the APD surface available to the UE 110, and/or transmission-direction information (e.g., beam-direction information for transmissions from the UE). The UE APD manager 214 directs the UE 110 to transmit communications with the base station 120 by using a surface of the APD and based on the APD- access information. In some implementations, the use of APDs in the communication path can be invisible to the UE, and the UE 110 need not include a UE APD manager 214 in such implementations.

[0028] The device diagram for the base station 120, shown in FIG. 2, includes a single network node (e.g., a gNode B). The functionality of the base station 120 may be distributed across multiple network nodes or devices and may be distributed in any fashion suitable to perform the functions described herein. The nomenclature for this distributed base station functionality varies and includes terms such as Central Unit (CU), Distributed Unit (DU), Baseband Unit (BBU), Remote Radio Head (RRH), Radio Unit (RU), and/or Remote Radio Unit (RRU). The base station 120 includes antennas 252, a radio-frequency front end 254 (RF front end 254), one or more wireless transceiver(s) 256 (e.g., radio-frequency transceivers) for communicating with the UE 110, such as LTE transceivers, 5G NR transceivers, and/or 6G transceivers. The RF front end 254 of the base station 120 can couple or connect the wireless transceivers 256 to the antennas 252 to facilitate various types of wireless communication. The antennas 252 of the base station 120 may include an array of multiple antennas that are configured in a similar manner or different from each other. The antennas 252 and the RF front end 254 can be tuned to, and/or be tunable to, one or more frequency bands defined by communication standards (e.g., 3GPP LTE, 5GNR, and/or 6G) and implemented by the wireless transceivers 256. Additionally, the antennas 252, the RF front end 254, and/or the wireless transceivers 256 may be configured to support beamforming, such as Massive-MIMO, for the transmission and reception of communications with the UE 110 and/or another base station 120.

[0029] The base station 120 also includes processor(s) 258 and computer-readable storage media 260 (CRM 260). The processor 258 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 260 may include any suitable memory or storage device, such as RAM, SRAM, DRAM, NVRAM, ROM, or Flash memory useable to store device data 262 of the base stations 120. The device data 262 includes network-scheduling data, radio resource-management data, applications, and/or an operating system of the base station 120, which are executable by processor(s) 258 to enable communication with the UE 110. The device data 262 also includes codebooks 264. The codebooks 264 may include any suitable type or combination of codebooks, including surface-configuration codebooks that store surface-configuration information for an RIS of an APD and beam-sweeping codebooks that store beam-sweeping patterns, sequences, APD- position information, and/or timing configurations (e.g., when to apply surface configurations) for implementing multiple surface-configurations useful to direct an APD to perform a variety of reflective beamforming. In some aspects, the surface-configuration codebooks and beamsweeping codebooks include phase-vector information, angular information (e.g., calibrated to respective phase vectors), and/or beam-configuration information. Generally, a beam-sweeping pattern corresponds to an order of surface configurations (and optionally APD reflection identifiers) that an APD cycles through (e.g., applies each surface configuration in succession based on timing configurations and/or information) to beam-sweep (reflected) signals in a horizontal direction and/or vertical direction. The beam-sweeping pattern may also indicate a time duration for applying each surface configuration and/or a position adjustment that moves the APD.

[0030] In aspects, the CRM 260 of the base station 120 also includes a base station adaptive phase-changing device manager 266 (BS APD manager 266) for managing APD usage in communication path(s) with the UE 110. Alternatively or additionally, the BS APD manager 266 may be implemented in whole or part as hardware logic or circuitry integrated with or separately from other components of the base station 120. In aspects, the BS APD manager 266 determines surface configurations for the APD (e.g., RIS configurations) based on link-quality measurements, measurement reports, measurement messages, UE location information, historical records, and/or other values. The BS APD manager 2660 may determine position configurations for the APD, such as a rotation or a linear adjustment of the APD, based on link quality measurements, signal quality measurements, and so forth. In some aspects, the BS APD manager 266 selects a surface configuration based on a beam-sweeping procedure as described with reference to FIGs. 7 and 8. The BS APD manager 272 may also apportion access (e.g., access to configure the RIS, access to utilize the surface for transmissions, subsets of configurable surface elements) to a single APD between multiple base stations (e.g., the base station 121 and the base station 122 share access to the surface of a single APD).

[0031] The CRM 260 also includes a base station manager 270 for managing various functionalities and communication interfaces of the base stations 120. Alternatively or additionally, the base station manager 270 may be implemented in whole or in part as hardware logic or circuitry integrated with or separately from other components of the base stations 120. In at least some aspects, the base station manager 270 configures the antennas 252, RF front end 254, and wireless transceivers 256 for communication with the UE 110 (e.g., the wireless link 131) and/or the APD 180 (e.g., the wireless link 132, the wireless link 133). The base station 120 sometimes includes a core network interface (not shown) that the base station manager 270 configures to exchange user-plane data and control-plane information with core network functions and/or entities. The base station 120 includes an inter-base-station interface 274 (inter-BS interface 274), such as an Xn and/or X2 interface, which the base station manager 270 configures to exchange user-plane and control-plane data between another base station 120, to manage the joint communications performed by base stations 120 participating in an ACS (with the UE 110) and/or for coordinating APD usage by the ACS.

[0032] FIG. 3 illustrates an example device diagram 300 of the APD 180. Generally, the device diagram 300 describes an example entity with which various aspects of multi-UE- communication transmissions using APDs can be implemented but may include additional functions and interfaces that are omitted from FIG. 3 for the sake of visual clarity. The adaptive phase-changing device (APD) 180 is an apparatus that includes a Reconfigurable Intelligent Surface (RIS) 322, and components for controlling the RIS 322 (e.g., by modifying the surface configuration of the RIS), as further described below. In some implementations, the APD 180 may also include components for modifying the position of the APD 180 itself, which in turn modifies the position of the RIS 322.

[0033] The APD 180 includes one or more antenna(s) 302, a radio frequency front end 304 (RF front end 304), and one or more radio-frequency transceivers 306 for wirelessly communicating with the base station 120 and/or the UE 110. The APD 180 can also include a position sensor 308, such as a Global Navigation Satellite System (GNSS) module, that provides position information based on a location of the APD 180.

[0034] The antenna(s) 302 of the APD 180 may include an array of multiple antennas that are configured in a similar manner or different from each other. Additionally, the antennas 302, the RF front end 304, and the transceiver(s) 306 may be configured to support beamforming for the transmission and reception of communications with the base stations 120. By way of example and not limitation, the antennas 302 and the RF front end 304 can be implemented for operation in sub-gigahertz bands, sub-6 GHz bands, and/or above 6 GHz bands. Thus, the antenna 302, the RF front end 304, and the transceiver(s) 306 provide the APD 180 with an ability to receive and/or transmit communications with the base station 120, such as information transmitted using the wireless link 132 and/or the wireless link 133.

[0035] The APD 180 includes processor(s) 310 and computer-readable storage media 312 (CRM 312). The processor 310 may be a single-core processor or a multiple-core processor implemented with a homogenous or heterogeneous core-structure. The computer-readable storage media described herein excludes propagating signals. CRM 312 may include any suitable memory or storage device such as RAM, SRAM, DRAM, NVRAM, ROM, or Flash memory useable to store device data 314 of the APD 180. The device data 314 includes user data, multimedia data, applications, and/or an operating system of the APD 180, which are executable by processor(s) 310 to enable dynamic configuration of the APD 180 as further described. The device data 314 also includes one or more codebooks 316 of any suitable type or combination and position information 318 of the APD 180. The position information 318 may be obtained or configured using the position sensor 308 or programmed into the APD 180, such as during installation. The position information 318 indicates a position of the APD 180 and may include a location, geographic coordinates, orientation, elevation information, or the like. A base station 120, by way of a BS APD manager 266, can use the position information 318 in computing angular or distance information, such as between the base station 120 and APD 180 and/or between the APD 180 and a group of UEs (e.g., the UE 111, the UE 112, the UE 113). The codebooks 316 can include surface-configuration codebooks that store surface-configuration information for an RIS of an APD and beam-sweeping codebooks that store patterns, sequences, or timing configurations (e.g., phase vectors and reflection identifiers) for implementing multiple surface-configurations useful to direct an APD to perform a variety of reflective beamforming. In some aspects, the surfaceconfiguration codebooks and beam-sweeping codebooks include phase-vector information, angular information (e.g., calibrated to respective phase vectors), and/or beam-configuration information.

[0036] In aspects of APDs for an ACS, the CRM 312 of the APD 180 includes an adaptive phase-changing device manager 320 (APD manager 320). Alternatively or additionally, the APD manager 320 may be implemented in whole or part as hardware logic or circuitry integrated with or separately from other components of the APD 180. Generally, the APD manager 320 manages a surface configuration of the APD 180, such as by processing information exchanged with a base station over wireless link(s) 132 and/or 133 and using the information to configure a reconfigurable intelligent surface 322 (RIS 322) of the APD 180. To illustrate, the APD manager 320 receives an indication of a surface configuration over the wireless link 132 (an APD control channel), extracts the surface configuration from the codebooks 316 using the indication, and applies the surface configuration to the RIS 322. Alternatively or additionally, the APD manager 320 initiates the transmission of uplink messages to the base station over the wireless link 132, such as acknowledgments/negative acknowledgments (ACKs/NACKs) for various APD configurations or management commands. In some aspects, the APD manager 320 receives an indication of a beam-sweeping pattern (e.g., beam-sweeping pattern index) over the wireless link 132 and applies a sequence of various surface configurations to the RIS based on the beamsweeping pattern and/or in accordance with a synchronization or pattern timing indicated by or received with the indication. [0037] The RIS 322 of the APD 180 includes one or more configurable surface element(s) 324, such as configurable electromagnetic elements, configurable resonator elements, or configurable reflectarray antenna elements. Generally, the configurable surface elements 324 can be selectively or programmatically configured to control how the RIS 322 reflects (e.g., directionality) and/or transforms incident waveforms. By way of example and not of limitation, configurable electromagnetic elements include scattering particles that are connected electronically (e.g., through PIN diodes). Implementations use the electronic connection to arrange the scattering particles, such as based on principles of reflection, to control a directionality, phase, amplitude, and/or polarization of the transformed waveform (from the incident waveform). The RIS 322 can include array(s) of configurable surface element(s) 324, where an array can include any number of elements having any size.

[0038] In some aspects, a position and/or orientation of the APD 180 is configurable, and the APD 180 includes a motor controller 326 communicating with one or more motor(s) 328 that are operably coupled with a physical chassis of the APD 180. Based on command and control information, such as received from a base station 120, the motor controller 326 can send commands to the motors 328 that alter one or more kinematic behaviors of the motors 328, which may include any suitable type of stepper motor or servo. For example, the motor controller 326 may issue commands or control signals that specify a shaft rotation of a stepper motor in degrees, a shaft-rotation rate of a stepper motor in revolutions per minute (RPM), a linear movement of a linear motor in millimeters (mm), a linear velocity of a linear motor in meters/second (m/s). The one or more motors 328, in turn, may be linked to mechanisms that mechanically position the physical chassis or a platform (e.g., avionics of a drone, a drive of a linear rail system, a gimble within a base station, a linear bearing within a base station) supporting the APD 180. Through the commands and signals, which the motor controller 326 generates and sends to the motors 328, a physical position, location, or orientation of the APD 180 (and/or the platform supporting the APD 180) may be altered. In response to receiving a position configuration from a base station, the APD manager 320 communicates movement commands to the motor controller 326, such as through a software interface and/or hardware addresses, based on the position configuration. In aspects of APDs for an ACS, a base station 120 may reposition or reorient one or more APDs 180 to improve or enable wireless signal reflections to be directed to the UE 110.

[0039] Generally, the APD 180 can include multiple motors, where each motor corresponds to a different rotational or linear direction of movement. Examples of motor(s) 328 that can be used to control orientation and location of the APD include linear servo motors that might be part of a (i) rail system mounting for the APD, (ii) motors controlling a direction and pitch, yaw, roll of a drone carrying the APD, (iii) radial servo or stepper motors that rotate an axis if the APD is in a fixed position or on a gimbal, and so on. For clarity, the motor controller 326 and the motors 328 are illustrated as being a part of the APD 180, but in alternative or additional implementations, the APD 180 communicates with motor controllers and/or motors external to the APD. To illustrate, the APD manager 320 communicates a position configuration to a motor controller that mechanically positions a platform or chassis that supports the APD 180. In aspects, the APD manager 320 communicates the position configuration to the motor controller using a local wireless link, such as Bluetooth®, Zigbee™, IEEE 802.15.4, or a hardwire link. The motor controller then adjusts the platform based on the position configuration using one or more motors. The platform can correspond to, or be attached to, any suitable mechanism that supports rotational and/or linear adjustments, such as a drone, a rail-propulsion system, a hydraulic lift system, and so forth.

[0040] As shown in FIG. 3, a position of the APD 180 may be defined with respect to a three-dimensional coordinate system in which an X-axis 330, Y-axis 332, and Z-axis 334 define a spatial area and provide a framework for indicating a position configuration through rotational and/or linear adjustments. While these axes are generally labeled as the X-axis, Y-axis, and Z- axis, other frameworks can be utilized to indicate the position configuration. To illustrate, aeronautical frameworks reference the axes as vertical (yaw), lateral (pitch), and longitudinal (roll) axes, while other movement frameworks reference the axes as vertical, sagittal, and frontal axes. As one example, position 336 generally points to a center position of the APD 180 that corresponds to a baseline position (e.g., position (0,0,0) using XYZ coordinates).

[0041] In aspects, the APD manager 320 communicates a rotational adjustment (e.g., rotational adjustments 338) around the X-axis 330 to the motor controller 326, where the rotational adjustment includes a rotational direction (e.g., clockwise or counterclockwise), an amount of rotation (e.g., degrees), and/or a rotation velocity. Alternatively or additionally, the APD manager 320 communicates a linear adjustment 340 along the X-axis, where the linear adjustment includes any combination of a direction, a velocity, and/or a distance of the adjustment. At times, the APD manager 320 communicates adjustments around the other axes as well, such as any combination of rotational adjustments 342 around the Y-axis 332, linear adjustments 344 along the Y-axis 332, rotational adjustments 346 around the Z-axis 334, and/or linear adjustments 348 along the Z-axis 334. Thus, the position configuration can include combinations of rotational and/or linear adjustments in all three degrees of spatial freedom. This allows the APD manager 320 to communicate physical adjustments to the APD 180. Alternatively or additionally, the APD manager communicates RIS surface configurations as further described. Controlling Adaptive Phase-Changing Devices

[0042] FIG. 4 illustrates an example 400 of configuring an APD 180 in accordance with one or more aspects. The example 400 includes instances of a base station 120 and an APD 180, which may be implemented similarly as described with reference to FIGs. 1-3. The RIS implemented by the APD 180 includes an array of “N” configurable surface elements, such as configurable surface element 402, configurable surface element 404, configurable surface element 406, and so forth, where “N” represents the number of configurable surface elements of the RIS.

[0043] In implementations, the base station 120 manages a configuration of the RIS of the APD 180 through use of a surface-configuration codebook 408, which can be preconfigured and/or known by both the base station 120 and the APD 180. Alternatively or additionally, the base station 120 may also manage a time-varying configuration of the RIS of the APD 180 through use of a beam-sweeping codebook. In some cases, the base station 120 transmits a surfaceconfiguration codebook 408 and/or a beam-sweeping codebook using the wireless link 132 and/or the wireless link 133, such as over an APD-slow-control channel using one or more messages. In aspects, the base station 120 uses the APD-slow-control channel to communicate large quantities of data, to communicate data without low-latency requirements, and/or to communicate data without timing requirements. At times, the base station 120 transmits multiple surfaceconfiguration codebooks to the APD 180, such as a first surface-configuration codebook for downlink communications, a second surface-configuration codebook for uplink communications, a phase-vector codebook, a beam-sweeping codebook, or the like. In response, the APD 180 stores the surface-configuration codebook(s) 408 and/or other codebooks in CRM, which is representative of codebook(s) 316 in CRM 312 as described with reference to FIG. 3. Alternatively or additionally, the APD 180 obtains the surface-configuration and other codebooks through manufacturing (e.g., programming), calibration, or installation processes that store the surface-configuration codebook(s) 408 and other codebooks in the CRM 312 of the APD 180 during assembly, installation, calibration, verification, or through an operator manually adding or updating the codebook(s).

[0044] The surface-configuration codebook 408 includes configuration information that specifies a surface configuration for some or all of the configurable surface elements (e.g., elements 324) forming the RIS of the APD 180. To illustrate, in some aspects, a phase vector defines a set of waveform transformation properties (e.g., phase delay, reflection angle/ directi on, polarization, amplitude) that a configurable surface element applies to an incident signal (e.g., incident waveform, incident signal ray) to transform the incident signal into a reflected signal (e.g., reflected waveform, reflected signal ray) characterized by one or more transformed properties. With respect to the surface-configuration codebook 408, each configuration entry may correspond to a phase vector or surface configuration associated with a set of waveform transformation properties provided by a respective configurable surface element of an APD when configured with the phase vector or surface configuration.

[0045] A surface configuration may include (or indicate) a surface element hardware configuration (e.g., for one or more PIN diodes) for each configurable surface element of the APD. In aspects, each surface element hardware configuration of a surface configuration may correspond to a respective entry in a phase vector. In other words, each surface element hardware configuration arranges the surface of a respective configurable surface element such that the respective configurable surface element transforms an incident waveform into a reflected waveform with waveform properties indicated by the corresponding phase vector entry. This can include absolute transformations based on the phase vector (e.g., generate a reflected waveform to within a threshold value/standard deviation of waveform properties indicated by the phase vector) or relative transformations (e.g., generate a reflected waveform based on modifying the incident waveform with the waveform properties indicated by the phase vector) to within a threshold value/standard deviation of the waveform properties. As one example, each index of the codebook corresponds to a phase vector and configuration information for each configurable surface element of the APD 180. Index 0, for instance, maps phase configuration 0 to configurable surface element 402, phase configuration 1 to configurable surface element 404, phase configuration 2 to configurable surface element 406, and so forth. Similarly, index 1 maps phase configuration 3 to configurable surface element 402, phase configuration 4 to configurable surface element 404, phase configuration 5 to configurable surface element 406, and so forth. The surface-configuration codebook 408 can include any number of phase vectors that specify configurations for any number of configurable surface elements such that a first phase vector corresponds to a first surface configuration for the APD 180 (by way of configurations for each configurable surface element in the RIS), a second phase vector corresponds to a second surface configuration for the APD 180, etc.

[0046] While the surface-configuration codebook 408 of FIG. 4 includes phase vector information, alternative or additional codebooks store beam configuration information, such as a first surface configuration that specifies a first beam with a first (propagation) direction, a second surface configuration that specifies a second beam with a second direction, etc. To illustrate, and similar to a phase vector surface configuration codebook, a beam cookbook includes surface element hardware configurations that correspond to a respective beam configuration. In other words, each surface element hardware configuration arranges the surface of a respective configurable surface element such that the respective configurable surface element transforms an incident waveform into a reflected waveform with beam properties (e.g., direction) indicated in the beam-codebook. Thus, in various implementations, the surface-configuration codebook 408 corresponds to a beam-codebook. Similarly, to configure the surface of the APD 180, the base station determines the desired beam configuration for the transformed signal and identifies an entry in the beam-codebook corresponding to the desired beam configuration (e.g., by identifying a beam-codebook index that maps to the entry). In some aspects, a phase-sweeping codebook indicates a pattern of surface configurations and/or beam configurations, such as surface configurations and/or beam configurations as indicated by the surface-configuration codebook 408 and beam configurations specified by the beam-codebook. To illustrate, the phase-sweeping codebook indicates an order of surface configurations to cycle through. Alternatively, or additionally, the phase-sweeping codebook indicates a time duration for applying each surface configuration.

[0047] The surface-configuration information stored in a codebook can correspond to a full configuration that specifies an exact configuration (e.g., configure with this value) or a delta configuration that specifies a relative configuration (e.g., modify a current state by this value). In one or more implementations, the phase configuration information specifies a directional increment and/or angular adjustment between an incident signal and a transformed signal. For instance, the phase configuration 0 can specify an angular adjustment configuration for element 402 such that the configurable surface element 402 reflects the incident waveform with a “phase configuration 0” relative angular or directional shift. As shown in FIG. 4, the base station 120 communicates an indication to the APD 180 that specifies a surface configuration. In the present example, the indication specifies a surface-configuration index 410 (SC index 410) that maps to a corresponding surface configuration of the APD 180. In response to receiving the indication, the APD manager 320 retrieves the surface configuration from the surface-configuration codebook 408 using the index and applies the surface configuration to the RIS. For example, the APD manager 320 configures each configurable surface element as specified by a respective entry in the surface-configuration codebook 408.

[0048] In various implementations, the base station 120 communicates timing configurations (not shown) to the APD 180, which may be included with a surface configuration or beam-sweeping index. For instance, the base station 120 sometimes indicates, to the APD 180 and using the wireless link 132 and/or the wireless link 133, a start time for the application of an indicated surface configuration or beam-sweeping pattern. In aspects, the base station 120 communicates a stop time that indicates when to remove and/or change the surface configuration or beam-sweeping pattern. In changing the surface configuration, the APD 180, by way of the APD manager 320, can apply a default surface configuration, return to a previous surface configuration (e.g., a surface configuration used prior to the indicated surface configuration), and/or apply a new surface configuration to control a direction in which the APD 180 reflects wireless signals. To maintain synchronized timing with the base station 120, the APD 180 receives and/or processes a base station synchronizing signal.

[0049] By specifying the timing configuration, the base station 120 can synchronize and/or configure the APD 180 to a particular UE (e.g., UE 110). For example, the base station 120 configures the APD 180 for the particular UE by specifying start and stop times that correspond to a time slot assigned to the particular UE. In aspects, the base station 120 transmits surfaceconfiguration indications and/or timing configurations using an APD-fast-control channel, which allows the base station 120 to dynamically configure the APD 180 on a slot-by-slot basis. For example, the base station 120 transmits a surface-configuration schedule to the APD that indicates when to apply different surface configurations to the RIS/configurable surface elements. Alternatively or additionally, the base station 120 communicates surface configuration changes on a slot-by-slot basis using signaling on the APD fast-control channel. These allow the base station to configure the APD for multiple UEs, such as in scenarios where at least two base stations share the APD to communicate with different UEs, and improve data rates, spectral efficiency, data throughput, and reliability for the multiple UEs and the corresponding wireless network.

Active Coordination Sets

[0050] FIG. 5 illustrates an example environment 500, in which aspects of APDs for an ACS may be implemented. In the environment 500, the UE 110 is moving through a radio access network (RAN) that includes multiple base stations 120, illustrated as base stations 121-127. These base stations may utilize different technologies (e.g., LTE, 5G NR, 6G) at a variety of frequencies (e.g., sub-gigahertz, sub-6 GHz, and above 6 GHz bands and sub-bands).

[0051] As the UE 110 follows a path 502 through the RAN 140, the UE 110 measures the link quality of base stations that are currently in the ACS and/or candidate base stations that the UE 110 evaluates, such as by periodically measuring broadcast signals. To illustrate, consider a scenario in which the UE participates in joint communications associated with an ACS. At position 504 on the path 502, the UE 110 communicates over the wireless network using an ACS 506 that includes the base stations 121, 122, and 123. Joint downlink transmissions, for example, correspond to a first signal transmission from the base station 121, a second signal transmission from the base station 122, and a third signal transmission from the base station 123. In some aspects, each base station transmits identical information using identical signaling (e.g., same time, same frequency, same coding, but potentially different spatial beams) on respective downlink signals to the UE to perform the joint transmission, which are combined at a receiver of the UE. In other aspects, each base station transmits a respective MIMO layer for MIMO communications to increase data throughput.

[0052] Alternatively, or additionally, the UE 110 transmits a single uplink signal that is jointly received by the set of base stations included in the ACS 506. The base stations within the ACS then communicate a respective received uplink signal (e.g., as in-phase and quadrature-phase (I/Q) digital samples of the received uplink signal) to a coordinating and/or master base station in the ACS. The coordinating base station combines the received uplink signals (e.g., received digital samples) for signal-level joint reception by the base stations and processes the combined uplink signal.

[0053] As the UE 110 continues to move, at position 508, the UE 110 evaluates various base stations by measuring a received signal strength of broadcast signals (e.g., downlink sounding reference signal (SRS)) received from the various base stations. Based on the evaluation, the UE 110 selects a new combination of base stations (e.g., for modifying an existing ACS, for forming a new ACS), such as by selecting base stations that have a received signal strength at or above a threshold value. At the position 508, the UE 110 selects a combination of base stations that includes the base stations 123, 124, and 125 for inclusion in an ACS and omits the base stations 121 and 122 from the selection. The UE 110 then transmits an indication of the selection to a coordinating base station of a current ACS (e.g., the ACS 506), such as by transmitting (e.g., using joint communications) an uplink SRS using an SRS resource that maps to the selection of base stations.

[0054] In response to receiving the indication of the selection transmitted by the UE 110 at the position 508, various implementations form an ACS 510 that includes the base station 123, the base station 124, and the base station 125. For example, a coordinating base station (e.g., base station 122) of the current ACS (e.g., the ACS 506) receives the uplink SRS, identifies the selection of base stations indicated by the UE 110, and coordinates the modifications to the current ACS to form the new ACS (e.g., ACS 510). In various implementations, the formation of the new ACS (e.g., ACS 510) corresponds to a modification of the current ACS insofar as the current ACS and the new ACS are specific to the UE 110 and have differences from one another, such as changes in the participating base stations. To illustrate, the modifications correspond to removing one or more base stations (e.g., the base stations 121 and 122) from the ACS specific to the UE 110 at position (and time) 504, and/or adding one or more base stations (e.g., the base stations 124 and 125) to the ACS specific to the UE 110 at position (and time) 508.

[0055] In some implementations, modifying an ACS specific to a UE includes changing a master base station (e.g., coordinating base station) that coordinates joint communications for the ACS. Consider, for example, a scenario in which the base station 122 acts as a current master base station to the ACS 506. In modifying the ACS 506 to form the ACS 510, the base station

122 selects a base station, such as base station 123, to act as a new master base station for the ACS 510 based on location information, signal strength information, supported core networks, and so forth. In implementations, the base station 122 requests and/or directs with the base station

123 to act as the new master base station, such as by exchanging commands, acknowledgments, configuration information, and so forth, through the Xn and/or X2 interfaces 106 of FIG. 1.

[0056] At times, the current master base station and/or the new master base station collectively coordinate the modifications to the ACS. For example, prior to directing the base station 123 to act as the new master base station, the current master base station (e.g., base station 122) removes base stations (e.g., base station 121) and/or adds new base stations (e.g., base stations 124 and 125) to the ACS specific to the UE 110, such as by sending respective commands to the base stations. As another example, the current master base station indicates, to the new master base station, which base station(s) to remove and which base station(s) to add to the ACS, and the new master base station manages modifying what base stations are included and excluded from the ACS. In yet another example, the current master base station removes base station(s) from the ACS, and the new master base station adds base station(s) to the ACS. As further described, in various implementations, the modifications to the ACS can be coordinated through messaging between the base stations using the Xn and/or X2 interfaces 106 of FIG. 1. Coordinating the modifications, at times, includes an exchange of information, such as exchanging UE capabilities associated with the UE 110, exchanging UE identification information, sending commands to join or leave an ACS, receiving acknowledgments, exchanging configuration information, and so forth.

[0057] Continuing along the path 502, the UE 110, at position 512, transmits a second indication of a second selection of base stations. Similar to that described with respect to the ACS 506 and the ACS 510, this results in the formation of the ACS 514 that modifies the ACS 510 by removing the base stations 123 and 124 from the ACS and adding the base station 127 to the ACS. In some implementations, the formation of the ACS 514 includes designating a new master base station (e.g., base station 125) for the ACS specific to the UE (e.g., ACS 514).

Adaptive Phase-Changing Devices for an Active Coordination Set

[0058] FIG. 6 illustrates an example environment 600 that can be used to implement various aspects of APDs for an ACS. The environment 600 includes the base station 121, the base station 122, the base station 123, the APD 181, the APD 182, and the UE 110 of FIGs 1 and 5. The base stations 121, 122, and 123 form an ACS 602 that jointly communicates with the UE 110 over the wireless link 131, which may include a low-band connection and/or a high-band connection. In aspects, one or more base stations (e.g., the base station 121, the base station 122) that participate in the ACS 602 include an APD in a respective communication path with the UE 110.

[0059] To illustrate, assume the base station 121 first establishes a communication link with the UE 110 using a low-band wireless connection 604 (low-band connection 604) that uses low-band frequencies (e.g., below 6 GHz) that are less susceptible to signal degradation relative to high-band and/or higher-frequency communications (e.g., above 6 GHz). The base station 121 and the UE 110 communicate information over the low-band connection 604 and determine to communicate with one another using a high-band wireless connection 606 (high-band connection 606). To illustrate, the UE 110 requests, over the low-band connection 604, to transfer a large quantity of user-plane data over the wireless network (e.g., uplink user-plane data and/or downlink user-plane data).

[0060] In response to the request, the base station 121 establishes the high-band connection 606 with the UE 110 and selects an APD to include in a communication path with the UE 110. Thus, in aspects, a base station may establish both a sub-6 GHz connection and an above 6GHz connection with a UE. Alternatively, one base station may serve the sub-6 GHz connection (e.g., FR1 connection) with the UE and another base station may serve the above 6 GHz connection (e.g., FR2 connection) with the UE. Returning to the present example, the UE 110, for instance, may communicate a variety of information to the base station 121 over the low-band connection 604, such as UE location information, signal-quality measurements, and/or linkquality measurements (e.g., generated from measuring downlink high-band wireless reference signals). Alternatively or additionally, the base station 121 generates signal-quality and/or linkquality measurements by measuring uplink high-band wireless reference signals from the UE 110. In response to analyzing any combination of information, the base station 121 determines to include an APD in the high-band communication path with the UE 110. For instance, the base station 121 identifies that the signal-quality and/or link-quality measurements fail to meet a performance threshold value and/or identifies from historical records that the UE 110 currently operates at a location associated with APD usage in a communication path between the base station 121 and other UEs.

[0061] In response to determining to include an APD in the communication path for the high-band connection 606, the base station 121 selects the APD 181 based on any combination of information, such as by monitoring for an APD-broadcast signal and/or message that announces a presence of the APD 181 to the base station 121, accessing APD records that indicate the APDs within a cell service area, and/or querying a server that stores information regarding APDs within the cell service area. The base station 120 may use location information received from the UE 110 over a low-band communication (or obtained using a beam-sweeping procedure) to identify APDs within an operating range of both the base station 121 and the UE 110. In some aspects, the base station 121 utilizes environment-sensing techniques, such as radar signals and/or cameras, to identify and/or select APDs within a threshold distance of the base station 121 and/or UE 110 to include in the communication path.

[0062] After selecting the APD 181, the base station 121 configures the reconfigurable surface of the APD 181. For example, as described with reference to FIG. 4, the base station selects a surface configuration from a codebook and/or look-up table (LUT) based on any combination of information (e.g., location information, signal -quality measurements, link-quality measurements, historical records) and transmits an indication of the surface configuration to the APD 181 using the wireless link 132, which can correspond to a high-band wireless communication link and/or a low-band wireless communication link. Alternatively or additionally, and as described with reference to FIG. 8, the base station 121 selects the surface configuration using a beam-sweeping procedure. In some aspects, the base station 121 selects the surface configuration using channel reciprocity principles. To illustrate, assume the base station 121 and the UE 110 communicate over the high-band connection 606 using time division duplex (TDD) communications. In selecting surface configurations for the APD 181, the base station 121 may initially select a first surface configuration for downlink communications based on a variety of information (e.g., UE location, signal-quality measurements, link-quality measurements). Using the channel reciprocity principles, and based on downlink communications with the UE 110 using TDD, the base station 121 may select a second surface configuration for uplink communications based on the first surface configuration.

[0063] After selecting and configuring the APD 181, the base station 121 communicates, or attempts to communicate, with the UE 110 using the high-band connection 606 by transmitting a wireless signal that includes rays 690 to the UE 110. In the environment 600, the rays 690 could be an omnidirectional wireless signal, but the rays 690 may form a wide beam (as shown) or a narrow beam (e.g., in a similar direction as ray 692). The rays 690, when implementing certain beamwidths, include a first signal ray 691 that propagates towards an obstruction 608 (illustrated as a building) that blocks the first signal ray 691 from reaching the UE 110. In other words, the obstruction 608 blocks at least a portion of the communication path between the base station 121 and the UE 110. The rays 690 also include a second signal ray 692 that propagates towards the APD 181, strikes the surface of the APD 181, and transforms into a third signal ray 693 that propagates towards the UE 110 in an LoS manner.

[0064] While the base station 120 transmits the rays 690 to the UE 110, the UE 110 can also communicate with the base station 120 using the high-band wireless connection 606 by transmitting uplink wireless signals towards the base station and/or the APD 181 in a manner reciprocal to the rays 693 and 692 (e.g., the ray 693 originates from the UE 110 and reflects off the surface of the APD 181 to form the ray 692 that propagates towards the base station 121).

[0065] In aspects, the UE 110 requests to include the base station 122 and/or the base station 123 in the ACS 602, where the request can correspond to a request to form the ACS 602 and/or a request to change and/or update base stations that participate in the ACS 602 as described with reference to FIG. 5. The UE 110, for instance, identifies a channel impairment in the high- band connection 606 by monitoring signal-quality and/or link-quality measurements and identifying when the signal-quality and/or link-quality measurements fall below a performance threshold. UE movement (reorientation or location change) as well as environment change (e.g., incoming fog or a passing truck) can cause the signal-quality and/or link-quality measurements to fall below the performance threshold.

[0066] In response to identifying the channel impairment, the UE 110 monitors a received signal strength of broadcast signals (e.g., an SSB or other downlink reference signal) received from various base stations and selects base stations (e.g., the base station 122, the base station 123) that have a received signal strength at or above a threshold value. Alternatively or additionally, the UE 110 selects the base station 122 and the base station 123 using UE location information and identifying base stations that are located within a threshold distance to the UE 110. The UE 110 may sequentially request adding the base station 122 and the base station 123 to the ACS 602 by transmitting the requests to the base station 121. As one example, the UE 110 transmits a first request to the base station 121 to add the base station 122 to the ACS, measures a performance of the ACS with the base station 122, and subsequently transmits a second request to the base station 121 to add the base station 123. Alternatively, the UE 110 transmits a single communication to the base station 121 that requests to add both the base station 122 and the base station 123 to the ACS 602. The request may specify to form the ACS 602 and/or to modify the ACS 602 and may be transmitted using the low-band connection 604 and/or the high- band connection 606.

[0067] In the environment 600, the base station 121 acts as a coordinating and/or master base station for the ACS 602. To illustrate, the base station 121 communicates directions and/or commands for adding the base station 122 to the ACS 602 using the interface 610 (e.g., a first instance of the interface 106) and to the base station 123 using the interface 612 (e.g., a second instance of the interface 106). In some aspects, the base station 121 also selects an APD for inclusion in a second communication path between another base station and the UE 110 (e.g., between the base station 122 and the UE 110) and communicates APD information to the other base station (e.g., over the interface 610), such as an APD identifier, APD position information, an APD reconfigurable surface configuration, timing configurations for using the APD in the communication path, and so forth. For example, based on UE location information and base station (BS) location information of the base station 122, the base station 121 identifies from historical records that past communications between the base station 122 and other UEs at the UE location used the APD 182 in the communication path. The base station 121 then directs the base station 122 to include the APD 182 in a communication path with the UE 110.

[0068] As the coordinating base station for the ACS 602, the base station 121 coordinates joint transmission and/or joint reception by the ACS, such as by directing the base stations 122 and 123 to transmit identical information using identical signaling (e.g., same time, same frequency, same coding, but potentially different spatial beams) on respective downlink signals to the UE for joint transmission, which are combined at a receiver of the UE. To illustrate, the base station 121 communicates data and a modulation configuration, or I/Q signals with directions to modulate and transmit the I/Q signals, to the base station 122 and the base station 123 using the respective interfaces 106. In some aspects, the base station 121 communicates antenna configurations to each of the base stations to form a specific multi -BS antenna configuration for transmissions by the ACS. Alternatively or additionally, the base station 121 may direct each of the base stations to add random phase shifts to the respective downlink signals to mitigate deconstructive interference at the receiver of the UE 110 and/or time shifts to improve constructive interference at the receiver of the UE 110. As another example, the base station 121 coordinates MIMO transmissions, such as by transmitting a first MIMO layer of a MIMO communication to the UE 110 and directing the base station 122 to transmit a second layer of the MIMO communication to the UE 110.

[0069] The base station 121 can also coordinate joint reception by the ACS. To illustrate, the base station 121 receives, over the interface 610 and the interface 612, digital samples (e.g., I/Q samples) of an uplink signal transmitted by the UE 110 and/or reflections off a surface of an APD and received by each of the base station 122 and the base station 123. The base station 121 combines the signals (e.g., after time aligning the signals) and processes the combined signal to recover a communication from the UE 110.

[0070] In some aspects, the base station 121 coordinates the APDs used by various base stations participating in the ACS, such as by selecting the APDs, selecting surface configurations for the APDs in a coordinated manner, and/or controlling random phase shifts introduced by the APDs (e.g., to mitigate deconstructive interference). As one example, the coordinating base station 121 and/or the base station 122 determine to include the APD 182 in a communication path between the base station 122 and the UE 110, such as by analyzing historical records, using UE location information, BS location information, and so forth, that indicate past usage of the APD 182. As another example, the base station 121 identifies that the APD 182 resides within a threshold distance to the base station 122 and includes the APD 182 in a beam-sweeping procedure as described with reference to FIG. 8. In evaluating results from the beam-sweeping procedure, the base station 121 identifies improvements in signal quality when including the APD 182 in the UE-to-base station 122 communication path. Accordingly, the base station 121 determines to include the APD 182 in communication paths for ACS communications. Accordingly, and as part of the ACS 602, the base station 122 reconfigures the surface of the APD 182 to direct and/or steer wireless signals. For example, as shown in FIG. 6, the base station 122 transmits a first signal ray 614 that propagates towards the APD 182, strikes the surface of the APD 182, and transforms into a second signal ray 616 that propagates towards the UE 110 in an LoS manner, which routes the wireless signal around obstruction 618. The UE 110 may alternatively or additionally transmit an uplink wireless signal in a manner reciprocal to the rays 616 and 614 as further described (e.g., the ray 616 originates from the UE 110 and reflects off the surface of the APD 182 to form the ray 614 that propagates towards the base station 122, and around the obstruction 618).

[0071] While the base station 121 and the base station 122 include APDs in the respective communication paths to the UE 110, the ACS 602 may alternatively or additionally include a base station that does not include an APD in a communication path with the UE 110. To illustrate, the base station 123 jointly communicates with the UE 110 as part of the ACS using a signal ray 620 that propagates towards the UE 110 in an LoS manner for downlink communications (shown in FIG. 6) and/or propagates from the UE 110 towards the base station 123 in the LoS manner for uplink communications (not shown in FIG. 6).

[0072] The base station 121 may select a first surface configuration for the APD 181 and a second surface configuration for the APD 182 using the beam-sweeping procedure. In some aspects, the base station 121 communicates the second surface configuration and directions to the base station 122 to configure the APD 182 (e.g., using the wireless link 133) using the second surface configuration. This may include communicating APD information to the base station 122, such as an APD identifier, the second surface configuration, APD position information, and/or APD timing configurations (e.g., when to apply the second surface configuration). Alternatively, the base station 121 directly communicates the second surface configuration to the APD 182 using an APD control channel. The base station 121 may use similar techniques to share a single APD with the base station 122 as further described.

[0073] In aspects, the base station 121 selects surface configurations for the APD 181 and/or the surface of the APD 182 to mitigate signal degradation, such as multipath fading. For example, using a receiver, the UE 110 combines the signal ray 693, the signal ray 616, and the signal ray 620. Because the signal rays travel different communication paths and originate from different base stations, they may arrive at the UE 110 at different times with different phase shifts which may result in deconstructive interference when combined at the receiver of UE 110. In implementations, the base station 121 selects surface configurations for the APD 181 and/or the APD 182 that transform incidents signals into reflected signals with particular properties (e.g., a particular phase shift) that mitigate signal degradation. The base station 121, for example, selects a surface configuration for the APD 181 to transform the signal ray 692 into the signal ray 693 with a phase shift for mitigating destructive interference when combined with the signal ray 616 and the signal ray 620.

[0074] While the environment 600 illustrates the base station 121 and the base station 122 utilizing separate APDs (e.g., the APD 181 and the APD 182) in the respective communication paths with the UE 110, alternative implementations include the base station 121 and the base station 122 sharing access to a single APD (not shown in FIG. 6), such as by apportioning the configurable surface elements of the single APD. To illustrate, the base station 121 apportions the configurable surface elements of the APD 181 into subsets of configurable surface elements, such as horizontal partitioning that groups a first subset of configurable surface elements (of the RIS) that are in a same horizontal row, vertical partitioning that groups a second subset of configurable surface elements that in a same vertical column, quadrant partitioning that groups subsets of configurable surface elements that are in a same quadrant of the RIS, and/or any other combination of suitable partition geometries. Based on the apportioned access, the base station

121 selects a first apportioned surface configuration for modifying a first subset of configurable surface elements of the APD 181 and a second apportioned surface configuration for modifying a second subset of configurable surface elements of the APD 181, and so forth. The first apportioned surface configuration, for instance, configures the first subset of configurable surface elements to direct and/or steer wireless signals between the base station 121 and the UE 110 (e.g., around the obstruction 608). The apportioned second configuration configures the second subset of configurable surface elements to direct and/or steer wireless signals between the base station

122 and the UE 110 (e.g., around the obstruction 618).

[0075] Because the UE 110 may have high mobility, the base station 121 may iteratively initiate a beam-sweeping procedure in which the APD 181 and/or other APDs (e.g., the APD 182) cycle through different surface configurations in a synchronized manner as described with reference to FIG. 8. As one example, and as part of the beam-sweeping procedure, the base station 121 directs the APD 181 to apply a beam-sweeping pattern to the APD reconfigurable surface, such as by indicating an index value that maps to an entry in a beam-sweeping codebook or to a timed sequence of entries in a surface-configuration codebook such as codebook 408. Alternatively or additionally, the base station 121 directs the APD 182, or commands the base station 122 to direct the APD 182, to apply a second beam-sweeping pattern. Generally, a beamsweeping pattern corresponds to an order of surface configurations that an APD cycles through (e.g., applies each surface configuration in succession based on timing configurations and/or information) to beam-sweep (reflected) signals in a horizontal direction and/or vertical direction. The beam-sweeping pattern may also indicate a time duration for applying each surface configuration and/or a position adjustment that moves the APD.

[0076] Modifying a surface configuration of the RIS changes how signals are transformed when they reflect off an RIS of an APD, such as by generating a reflected signal that helps decrease destructive interference and/or improve constructive interference when a receiver combines the reflected signal with other signals. Alternatively or additionally, the RIS configuration redirects the reflective signals around LoS obstructions, which allows the base stations participating in the ACS to mitigate conditions that might otherwise cause recovery errors at a receiver. This also improves data rates, data throughput, and reliability in a wireless network.

Signaling and Control Transactions for APDs for an ACS

[0077] FIGs. 7 and 8 illustrate example signaling transaction diagrams in accordance with one or more aspects of APDs for an ACS. The transactions may be performed by a combination of devices, including at least two base stations (e.g., the base station 121 and the base station 122), one or more APDs (e.g., the APD 181 and the APD 182), and a UE (e.g., the UE 110). The example signaling transactions may be implemented using aspects as described with reference to any of FIGs. 1-6.

[0078] FIG. 7 illustrates a first example diagram 700 that illustrates signaling transactions between the base station 121, the base station 122, the APD 181, the APD 182, and the UE HO of FIG. 1. While not shown in the diagram 700, the transactions shown and described can alternatively or additionally be implemented to use apportioned access to a single APD. Optional transactions and/or operations are denoted through the use of a dashed line.

[0079] At 705, the base station 121 communicates with the UE 110 over a wireless link. As one example, the base station 121 communicates with the UE 110 using a low-band wireless link, such as the low-band connection 604 of FIG. 6. Alternatively or additionally, the base station 121 communicates with the UE 110 over a high-band wireless link, such as the high-band connection 606 of FIG. 6. In aspects, the base station may establish both a sub-6 GHz connection and an above 6GHz connection with a UE. Alternatively, one base station may serve the sub-6 GHz connection (e.g., FR1 connection) with the UE and another base station may serve the above 6 GHz connection (e.g., FR2 connection) with the UE, with the base stations being co-located or implemented at separate ground sites. This can include the base station 121 and/or the UE 110 optionally using the surface of the APD 181 in a communication path as described with reference to FIGs. 1 and 6. While not shown in the diagram 700, at 705, the base station 121 may communicate with the UE 110 as part of an ACS.

[0080] At 710, the UE 110 evaluates base stations to include in an ACS. To illustrate, and as described with reference to FIGs. 5 and 6, the UE 110 identifies a channel impairment (e.g., by evaluating signal-quality and/or link-quality measurements) and/or a location change greater than a threshold value (e.g., using a GPS of the UE). In response to identifying the location change and/or the channel impairment, the UE 110 evaluates base stations to include in the ACS for joint communications with the UE, such as by measuring power levels of downlink CSI-RSs or SSBs from various base stations and identifying the base stations associated with power levels above a performance threshold value. Alternatively or additionally, the UE 110 periodically measures the received signal power levels of reference signals from the various base stations and identifies power levels that meet or exceed the performance threshold value.

[0081] At 715, the UE 110 sends a request (or a message) to add a base station to an ACS. The UE 110, for example, transmits the request to the base station 121 using a low-band wireless link or a high-band wireless link. In some aspects (e.g., when an APD is configured to participate in the communication path (e.g., of operation 705) between the UE 110 and the BS 121), the UE 110 optionally includes the surface of the APD 181 in the communication path for the transmission that carries the request. The request may specify the identity of one or more base stations to include in the ACS, an indication to form a new ACS, and/or an indication to modify an existing ACS.

[0082] At 720, the base station 121 directs the base station 122 to participate in an ACS that jointly communicates with the UE 110, such as by communicating the directions over an Xn or X2 interface (e.g., interface 106 of FIG. 1, interface 274 of FIG. 2). In some aspects, the base station 121 optionally directs the base station 122 to include an APD in a communication path with the UE, such as by selecting the APD based on analyzing historical records and communicating an APD identifier to the base station 122 as described with reference to FIG. 6. Alternatively or additionally, the base station 121 communicates UE location information to the base station 122.

[0083] At 725, the base station 122 optionally communicates a request to coordinate APD usage for the ACS communications. To illustrate, using the UE location information, the base station 122 accesses historical records that indicate the base station 122 used the APD 182 in communication paths with other UEs previously operating at the UE location. Accordingly, in some aspects, the base station 122 identifies the APD 182 as an APD to use in a communication path with the UE 110, and requests that the base station 121 (acting as a coordinating and/or master base station of the ACS) coordinate APD usage with the APD 182. In other words, the base station 122 identifies a specific APD (e.g., the APD 182) in the request to coordinate APD usage.

[0084] At 730, the base station 121 performs a beam-sweeping procedure as described with reference to FIG. 8, which can include the participation of the base station 121, the base station 122, the APD 181, the APD 182, and/or the UE 110. As one example, the base station 121 transmits a first downlink signal towards the surface of the APD 181 while the APD 181 cycles through multiple surface configurations in accordance with a first beam-sweeping pattern. In some aspects, the base station 121 uses a channel state information (CSI) process in which the base station changes what air interface resource(s) are used to transmit the downlink signal (e.g., air interface resources specified through channel state information reference signal (CSI RS) parameters), where the changes in air interface resources are synchronized with when the APD 181 changes a surface configuration. In other words, as part of the CSI process, the base station 121 transmits the downlink signal using air interface resources corresponding to a specific combination of CSI RS parameters, and synchronizes the transmission with when the APD 181 applies the surface configuration (e.g., the surface configuration mapped to the specific combination of CSI RS parameters). The UE 110 measures reflected signals off the APD reconfigurable surface, which can include the UE 110 generating CSI, and sends the measurements to the base station. By analyzing the measurements and which air interface resources include the reflected signal, the base station can identify the corresponding surface configuration. Alternatively or additionally, the UE 110 transmits an uplink signal in a reciprocal manner, which the base station 121 measures.

[0085] In a similar manner as described with reference to the base station 121, and as part of the beam-sweeping procedure, the base station 122 may transmit a second downlink signal towards the surface of the APD 182, where the APD 182 cycles through multiple surface configurations in accordance with a second beam-sweeping pattern. To illustrate, the base station 122 synchronizes the transmission with the APD 182 applying a particular surface configuration and transmits the downlink signal using air interface resources corresponding to a specific combination of CSI RS parameters. Thus, in some aspects, the specific combination of CSI RS parameters map to a combination of surface configurations (e.g., a first surface configuration at the APD 181, a second surface configuration at the APD 182). The second downlink signal may be combined at a receiver of the UE 110 with the first downlink signal such that the UE-generated measurements correspond to the combined received signals.

[0086] At 735, the base station 121 selects one or more surface configurations for one or more APDs. For example, the base station 121 analyzes UE-generated measurement results for downlink signals and/or base station-generated measurement results for uplink signals and identifies a measurement result with acceptable performance (e.g., a first measurement result with acceptable performance, a best measurement result in a set). In response to identifying a measurement result with acceptable performance, the base station 121 selects one or more surface configurations, such as a first surface configuration for the APD 181 and/or a second surface configuration for the APD 182. As one example, the base station 121 identifies a set of air interface resources associated with a measurement result with acceptable performance and selects the surface configuration(s) that map to the air interface resources. In some aspects, the base station 121 selects, as the first and second surface configurations, surface configurations for partitions of a single APD. Alternatively or additionally, the base station 121 selects surface configurations to form (e.g., via the reflected signals) a particular transmit diversity pattern. In some aspects, the base station 121 selects timing configurations as part of the surface configurations, such as timing configurations that indicate to an APD when to apply the surface configurations. To illustrate, the base station 121 selects a first timing configuration associated with applying the first surface configuration at the APD 181 and a second timing configuration associated with applying the second surface configuration at the APD 182.

[0087] Selecting the surface configurations based on a measurement result that meets or exceeds a performance threshold value improves how the APDs direct, steer, and/or modify the reflected signals in a manner that improves the jointly transmitted and/or jointly received signals. This improves the performance of communications in a wireless network by reducing data-transfer latencies and increasing data throughput.

[0088] At 740, the base station 121 directs the APD 181 and/or the APD 182 to apply a selected surface configuration. This can include the base station communicating with the APD 181 using a first wireless link (e.g., the wireless link 132) and the APD 182 using a second wireless link (e.g., the wireless link 133), communicating with the APD(s) using a hardwire interface, or communicating a surface configuration to the base station 122 (not shown in FIG. 7) and directing the base station 122 to configure the APD 182. Alternatively, the base station 121 communicates two or more surface configurations to a single APD, such as when the base station 121 apportions reflection access to the single APD and each surface configuration configures a subset of configurable surface elements.

[0089] At 745, the base stations participating in the ACS (e.g., the base station 121, the base station 122) jointly communicate with the UE 110 by performing j oint transmission and/or joint reception as described with reference to FIGs. 1, 5, and 6. In aspects, one or more of the base stations include an APD in a communication path with the UE, such as by sharing a single APD, using different APDs, or only some of the base stations participating in the ACS including an APD in the communication path.

[0090] At 750, the base station 122 optionally requests an update to a surface configuration for an APD included in the communication path between the base station 122 and the UE 110. As one example, while performing joint reception, the base station 122 generates uplink signalquality and/or link-quality measurements and identifies when one or more of the measurements fail to meet a performance metric. In response, the base station 122 communicates a request for an update to a surface configuration to the base station 121.

[0091] At 755, and in a similar manner as the base station 122, the base station 121 optionally determines to update one or more surface configurations of the APDs used in the communication paths. In one example, the base station 121 determines to update the surface configurations in response to receiving a request from the base station 122. Alternatively or additionally, the base station 121 receives UE-generated measurements for downlink signals and/or generates uplink measurements that indicate a channel impairment and determines to update the surface configurations. The base station 121 may also determine to update the surface configurations in response to identifying a location change of the UE 110 that exceeds a distance threshold value.

[0092] In response to determining to update the surface configurations, and as shown at 760, the transactions shown by the diagram 700 may iteratively repeat. To illustrate, in response to determining to update the surface configuration(s), the base station 121 initiates a beamsweeping procedure at 730, selects the updated surface configurations at 735, updates the APD(s) at 740, and jointly communicates with the UE 110 as part of an ACS.

[0093] FIG. 8 illustrates a second example of signaling and control transactions for APDs for an ACS. In aspects, FIG. 8 provides details of an implementation of block 725 of FIG. 7 and thus shows the same network elements (the base station 121, the base station 122, the APD 181, the APD 182, and the UE 110). The example signaling transactions may be implemented in combination with and/or using aspects as described with reference to any of FIGs. 1-7. While not shown in the diagram 800, the transactions shown and described can alternatively or additionally be implemented to use apportioned access to a single APD.

[0094] At 805, the base station 121 initiates a beam-sweeping procedure performed by multiple devices, such as any combination of the base station 121, the base station 122, the APD 181 and/or the APD 182, and the UE 110. As one example, the base station 121 directs the base station 122 to initiate the beam-sweeping procedure in which the base station 122 transmits a downlink signal towards a surface of an APD (e.g., the APD 182, a portion of the APD 181) and/or receives an uplink signal reflected off the surface of the APD as further described. In aspects, the base station 121 sends a first command to the APD 181 that directs the APD 181 to apply a first beam-sweeping pattern and a second command to the APD 182 (e.g., directly using an APD control channel, indirectly through the base station 122) to apply a second beam-sweeping pattern. This can include initiating a beam-sweeping procedure in which (i) a first APD maintains a same surface configuration and a second APD applies a set of surface configurations (associated with a beam-sweeping pattern) in succession based on timing configurations and/or information, or (ii) the first APD and the second APD each apply a respective set of surface configurations (associated with respective beam-sweeping patterns and respective timing information) in a coordinated an iterative manner.

[0095] At 810, the base station 120 optionally requests measurement reports from the UE 110. In aspects, the request specifies one or more measurement configurations that direct the UE 110 to monitor and/or measure downlink (high-band) wireless reference signals, extract beam identities from certain received downlink (high-band) wireless signals, transmit measurement reports back to the base station 121, and/or include beam identities in the measurement reports. In some aspects, the base station 120 optionally directs the UE 110 to transmit uplink sounding signals and/or modulate beam identities onto the uplink signals as part of the beam-sweeping procedure.

[0096] At 815, the APD 181 applies a first downlink surface configuration, and at 820, the APD 182 applies a second downlink surface configuration, where a downlink surface configuration generally corresponds to a surface configuration associated with directing downlink wireless signals to an intended target device. As one example, assume, at 805, the base station 120 directs the APD 181 to maintain a downlink surface configuration for the duration of the beam-sweeping procedure and directs the APD 182 to apply a set of surface configurations in succession (e.g., a beam-sweeping pattern). At 815, the APD 181 may apply the first downlink surface configuration once and then maintain the first downlink surface configuration for the duration of the beam-sweeping procedure and/or until receiving other directions from the base station 121. At 820, the APD 182 may iteratively apply a set of surface configurations in succession and based on time information in a beam-sweeping pattern, further shown in the diagram 800 at 845.

[0097] As another example, at 805, the base station 121 directs the APD 181 to apply a first downlink beam-sweeping pattern and the APD 182 to apply the second downlink beamsweeping pattern (e.g., beam-sweeping patterns that include downlink surface configurations). In aspects, the APD 181 cycles through a first set of surface configurations associated with the first downlink beam-sweeping pattern and the APD 182 cycles through the second set of surface configurations in a coordinated and iterative manner to cycle through the different combinations of surface configuration pairs. This may include the base station 121 directing the APD 181 and/or the APD 182 to perform a full beam-sweeping procedure that sweeps through all surface configurations in a set of surface configurations (e.g., a set of surface configurations that covers a full range of predetermined reflection angles) or a partial beam-sweeping procedure that sweeps through a subset of surface configurations in the set of surface configurations.

[0098] To illustrate, the base station 121 may direct the APD 181 and/or the APD 182 (e.g., directly or through the base station 122) to use partial beam-sweeping patterns or broad beam-sweeping patterns. As one example, the base station 121 may direct the APD 182 to use a broad beam-sweeping pattern in which the APD 182 applies a sequence of surface configurations that correspond to a broad beam-sweeping pattern of over 90 degrees and perhaps to almost 180 degrees. The broad beam-sweeping pattern configures the RIS to reflect an incident beam such that the reflected beam incrementally spans or sweeps a spatial region broadly (e.g., sweeping 150 degrees to 30 degrees in 5-degree steps over the duration of the beam-sweeping procedure). In other words, the sequence of surface configurations corresponds to a set of phase vectors in a surface-configuration codebook, where each phase vector corresponds to a respective reflection angle. Alternatively or additionally, the base station 121 directs the APD 181 to use a partial beam-sweeping pattern in which the APD 182 applies a subset of surface configurations such that the (resultant) partial beam-sweeping pattern configures the RIS to sweep the reflected beam incrementally over a smaller spatial region (e.g., approximately 90 degrees to 60 degrees in 5- degree steps). While described as sweeping through a sequence of surface configurations, the beam-sweeping patterns can alternatively or additionally sweep through a sequence of APD/ APD reconfigurable surface positions (e.g., azimuth positioning, elevation positioning).

[0099] In performing the beam-sweeping procedure, the APD 181 applies and maintains a first surface configuration of a first downlink beam-sweeping pattern at 815 while the APD 182 cycles through the surface configurations defined by a second beam-sweeping pattern at 820. As the beam-sweeping procedure progresses as shown at 845, the APD 181 iterates through the first downlink beam-sweeping pattern by applying and maintaining a second surface configuration of the first downlink beam-sweeping pattern at 815 while the APD 182 (re)cy cles through the surface configurations defined by the second downlink beam-sweeping pattern at 820. Accordingly, at 815 and at 820, the APD 181 and the APD 182 may apply respective next surface configurations at different times from one another.

[0100] At 825, the base station 121 transmits one or more downlink wireless signals towards a surface of the APD 181. Similarly, the base station 122 transmits one or more downlink wireless signals towards a surface of the APD 182. This may include each base station changing which air interfaces are used to transmit the downlink wireless signals (e.g., as part of the CSI process).

[0101] At 830, the UE 110 generates downlink measurements on the downlink wireless signal(s) (e.g., a received signal corresponding to the combined downlink wireless signals from the base station 121 and the base station 122). As one example, the UE generates an RSRP measurement using the received downlink wireless signal. As another example, the UE generates CSI.

[0102] At 835, the UE 110 communicates one or more downlink measurement reports to the base station 121 (e.g., via one or more respective messages). In communicating the downlink measurement report(s) to the base station 121, the UE 110 may use a low-band wireless link without (intentionally) using the surfaces of the APD 181. Alternatively, the UE 110 transmits the measurement reports using a high-band wireless link that is jointly received by the base station 121 and the base station 122, shown at 840 where the base station 122 optionally communicates the received signal and/or information to the base station 121. The UE may report measurements at every interval that reflects a change in either of the surface configurations at 815 and/or at 820 (e.g., intervals specified in the measurement report request) or may batch-report received signal measurements on a less-frequent basis. Examples include sending received signal measurements when the measurements exceed a threshold, after a cycle is completed (e.g., sweeping pattern at 815 or at 820 is completed), or after completing multiple cycles.

[0103] Sub-diagram 850 includes a first set of signaling and control transactions that corresponds to a downlink beam-sweeping procedure in which the base station 121 and the base station 122 transmit downlink wireless signals that are (potentially) reflected off the surfaces of the APD 181 and/or APD 182 and measured by the UE 110. As indicated at 845, the first set of signaling and control transactions included in the sub-diagram 850 may iteratively repeat based on one or more beam-sweeping patterns to cycle through surface configuration pairs as further described. The sub-diagram 850 may optionally be included in the beam-sweeping procedure. To illustrate, in some aspects, the base station 121 determines to perform only an uplink beamsweeping procedure to select uplink surface configurations for jointly received uplink communications and determines to exclude the first set of signaling and control transactions included in the sub-diagram 850 for time-saving purposes. For example, the base station 121 selects downlink surface configuration(s) based on the channel reciprocity principles and using uplink surface configuration(s) selected through an uplink beam-sweeping procedure.

[0104] Sub-diagram 855 includes a second set of signaling transactions that corresponds to an uplink beam-sweeping procedure in which the UE 110 transmits uplink wireless signals that (potentially) reflect off the surfaces of the APD 181 and/or APD 182, which the base station 121 and base station 122 jointly receive as part of an ACS. As indicated at 860, the second set of signaling transactions included in the sub-diagram 855 may iteratively repeat to cycle through surface configuration pairs based on one or more beam-sweeping patterns. The sub-diagram 855 may optionally be included in the beam-sweeping procedure as part of block 725. To illustrate, in some aspects, the base station 120 determines to perform only a downlink beam-sweeping procedure as shown by the sub-diagram 850 to select downlink surface configurations for downlink joint transmissions and determines to use the channel reciprocity principles to select uplink surface configurations (and exclude the second set of signaling transactions included in the sub-diagram 855 for time-saving purposes).

[0105] At 865, the APD 181 applies a first uplink surface configuration, and at 870, the APD 182 applies a second uplink surface configuration, where an uplink surface configuration generally corresponds to a surface configuration associated with directing uplink wireless signals to an intended target device. Similar to that described with reference to the sub-diagram 850, this can include a first APD maintaining a surface configuration while a second APD cycles through a first uplink beam-sweeping pattern (e.g., beam-sweeping patterns that include multiple uplink surface configurations), or each APD cycling through a respective uplink beam-sweeping pattern in a coordinated and iterative manner.

[0106] At 875, the UE 110 transmits one or more uplink wireless signals (e.g., an SRS). Alternatively or additionally, the UE 110 modulates a beam identity on the uplink wireless signals. To illustrate, the UE 110 transmits one or more uplink wireless signals, some rays of which strike the surface of the APD 182 and are received by the base station 122, which the base station 122 then forwards to the base station 121 at 880 (e.g., digital samples of the received signal). Alternatively or additionally, some rays strike the surface of the APD 181 and are received by the base station 121.

[0107] At 885, the base station 121 generates uplink measurements based on the uplink wireless signals jointly received by the base station 121 and the base station 122. In aspects, the base station 121 then uses any combination of the downlink measurement reports and/or the uplink measurement reports (e.g., at 735 of FIG. 7) to select a surface configuration pair (e.g., from the beam-sweeping pattem(s)) for the APDs that route and/or transform wireless signals between the UE 110 and base stations participating in the ACS.

Example Methods for APDs for an ACS

[0108] Example method 900 is described with reference to FIG. 9 in accordance with one or more aspects of APDs for an ACS. The example method 900 used to perform aspects of APDs for an ACS may be performed by a base station, such as the base station 120 of FIG. 1. [0109] At 905, a base station receives a request or message from the UE to add an additional base station to an ACS or maintain a base station of an ACS. To illustrate, the base station 121 receives a request from the UE 110 as described at 715 of FIG. 7, where the request indicates to form an ACS that includes the base station 121 and the additional base station, or indicates to modify an existing ACS by including the additional base station. Each base station participating in the ACS communicates with the UE using joint communications (e.g., joint transmission and/or joint reception).

[0110] At 910, the base station selects a surface configuration for a surface of an APD included in a first communication path between the UE and the first base station or a second communication path between the UE and the additional base station. As one example, the base station 121 selects a first surface configuration for the APD 181 and a second configuration for the APD 182 as described at 735 of FIG. 7. In some aspects, the base station 121 selects surface configurations for subsets of configurable surface elements. In aspects, the base station selects the surface configuration based on joint communications performed by the base stations participating in the ACS, such as through a beam-sweeping procedure in which the base stations jointly transmit a downlink signal and/or jointly receive an uplink signal as described with reference to FIG. 8.

[0111] At 915, the base station directs the APD to apply the surface configuration to the surface of the APD. To illustrate, the base station 121 directs the APD 181 to apply the first surface configuration as described at 740 of FIG. 7. Alternatively or additionally, the base station 121 directs the APD 182 to apply the second surface configuration, which can include the base station 121 communicating directly with the APD 182 (e.g., using an APD control channel) or indirectly with the APD 182 (e.g., through the base station 122).

[0112] At 920, the base station 121 communicates with the UE as part of the ACS by performing the joint communications with the UE using the APD in the first communication path or the second communication path. To illustrate, and as described with reference to FIG. 6 and at 745 of FIG. 7, the base station 121 jointly transmits a downlink signal to the UE 110 and/or jointly receives an uplink signal from the UE 110 using a surface of the APD 181. As another example, an ACS may include at least a first base station and a second base station performing joint communications with a UE. The UE may detect an impairment or decrease in signal quality of joint communications (or beam-sweep procedure) related to the second base station (e.g., due to UE movement, a dynamic signal blocker, or changing weather conditions) and request that the first base station to add the APD to the communication path between the second base station and the UE or adjust the surface configuration of the APD to maintain the joint communications (e.g., preclude a handover to another base station). This is but one example of how an APD may be used to enable and/or maintain joint communications between base stations in an ACS with the UE.

[0113] The order in which the method blocks of the method 900 is described is 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 alternative method. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), 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-Chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

[0114] Although aspects of APDs for an ACS have been described in language specific to features and/or methods, the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations of APDs for an ACS, and other equivalent features and methods are intended to be within the scope of the appended claims. Thus, the appended claims include a list of features that can be selected in “any combination thereof,” which includes combining any number and any combination of the listed features. Further, various different aspects are described, and it is to be appreciated that each described aspect can be implemented independently or in connection with one or more other described aspects.

[0115] A number of aspects are now set out.

[0116] Aspect 1 : A method performed by a first base station for coordinating and maintaining joint communications with a user equipment, UE, in a wireless network, the method comprising: receiving a message from the UE to add or to maintain a second base station in an active coordination set, ACS, at least the first base station and the second base station in the ACS performing the joint communications that include one of: joint transmission to the UE or joint reception from the UE; selecting a surface configuration for an adaptive phase-change device, APD, of one or more available APDs, to be included in a communication path between the UE and the second base station in the ACS; directing the APD to apply the surface configuration; and coordinating the joint communication of the ACS with the UE, the ACS including the second base station that communicates with the UE using the APD. [0117] The method may further comprise selecting the APD from the one or more available APDs to include in the communication path between the UE and the second base station based on the message from the UE.

[0118] The message from the UE may include one or more measurements for the communication path between the UE and the second base station; and the selecting of the APD to include in the communication path may use the one or more measurements.

[0119] The message from the UE may include one or more measurements for the communication path between the UE and the second base station; and the selecting of the surface configuration for the APD may use the one or more measurements.

[0120] At least one measurement of the one or more measurements for the communication path between the UE and the second base station may indicates one of: an impairment of the communication path between the UE and the second base station; an obstacle between the UE and the second base station; a decrease in signal quality of the joint communications between the UE and the second base station; and a decrease in signal strength of the j oint communications between the UE and the second base station.

[0121] The selecting of the surface configuration for the APD may further comprise selecting the surface configuration based on one of: a location of the UE; historical records indicative of use of the APD with the UE or other UEs proximate the location of the UE; and a change in the location of the UE.

[0122] The method may further comprise selecting the APD from the one or more available APDs to include in the communication path between the UE and the second base station based on one of: a location of the UE; historical records indicative of use of the APD with the UE or other UEs proximate the location of the UE; and a change in the location of the UE.

[0123] The method may further comprise identifying the change in the location of the UE using a distance threshold value.

[0124] The method may further comprise receiving a request from the second base station to coordinate the joint communications using the APD in the communication path between the UE and the second base station; and selecting the APD from the one or more available APDs to include in the communication path based on the request from the second base station.

[0125] The method may further comprise performing a beam-sweeping procedure to generate one or more measurements of the communication path between the UE and the second base station; and the selecting of the surface configuration for the APD may use the one or more measurements generated by the beam-sweeping procedure.

[0126] The method may further comprise performing a beam-sweeping procedure to generate one or more measurements of the communication path between the UE and the second base station; and selecting the APD from the one or more available APDs to include in the communication path may use the one or more measurements generated by the beam-sweeping procedure.

[0127] The one or more measurements may indicate that signal-related conditions of the communication path between the UE and the second base station are improved based on the APD being included in the communication path.

[0128] The directing of the APD to apply the surface configuration may further comprise communicating the surface configuration for the APD to the second base station; and directing the second base station to communicate the surface configuration to the APD.

[0129] The selecting of the surface configuration for the APD may be based on a transmit diversity pattern for the joint communications.

[0130] The selecting of the surface configuration for the APD may further comprise selecting, as the surface configuration, a downlink surface configuration for downlink communications from the second base station to the UE; and directing the APD to apply an uplink surface configuration for uplink communications from the UE to the second base station using channel reciprocity principles and the downlink surface configuration; or selecting, as the surface configuration, the uplink surface configuration for the uplink communications from the UE to the second base station; and directing the APD to apply the downlink surface configuration for the downlink communications from the second base station to the UE using the channel reciprocity principles and the uplink surface configuration.

[0131] The coordinating of the joint communications may comprise communicating with the UE using a first multiple input, multiple output, MIMO, layer; and directing the second base station to communicate with the UE using a second MIMO layer.

[0132] A first communication path between the UE and the first base station may include the APD, the communication path between the UE and the second base station may be a second communication path, and the selecting of the surface configuration for the APD may further comprise selecting a first apportioned surface configuration that configures a first subset of configurable surface elements of a surface of the APD in the first communication path between the UE and the first base station; and selecting a second apportioned surface configuration that configures a second subset of the configurable surface elements of the surface of the APD in the second communication path between the UE and the second base station, the directing of the APD to apply the surface configuration may further comprise directing the APD to apply the first apportioned surface configuration and the second apportioned surface configuration. [0133] Aspect 2: An apparatus comprising: a wireless transceiver; a processor; and a computer-readable storage medium comprising instructions, when executed by the processor, direct the apparatus to carry out steps of the method as recited in any of claims 1 to 17.

[0134] Aspect 3: A computer-readable storage medium comprising instructions, when executed by a processor, direct an apparatus to carry out steps of the method as recited in any of claims 1 to 17.

Claims

CLAIMS What is claimed is:

1. A method performed by a first base station for coordinating and maintaining joint communications with a user equipment, UE, in a wireless network, the method comprising: receiving a message from the UE to add or to maintain a second base station in an active coordination set, ACS, at least the first base station and the second base station in the ACS performing the joint communications that include one of: joint transmission to the UE or joint reception from the UE; selecting a surface configuration for an adaptive phase-change device, APD, of one or more available APDs, to be included in a communication path between the UE and the second base station in the ACS; directing the APD to apply the surface configuration; and coordinating the joint communication of the ACS with the UE, the ACS including the second base station that communicates with the UE using the APD.

2. The method as recited in claim 1, further comprising: selecting the APD from the one or more available APDs to include in the communication path between the UE and the second base station based on the message from the UE.

3. The method as recited in claim 2, wherein: the message from the UE includes one or more measurements for the communication path between the UE and the second base station; and the selecting of the APD to include in the communication path uses the one or more measurements.

4. The method as recited in claim 1, wherein: the message from the UE includes one or more measurements for the communication path between the UE and the second base station; and the selecting of the surface configuration for the APD uses the one or more measurements.

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5. The method as recited in claim 3 or claim 4, wherein at least one measurement of the one or more measurements for the communication path between the UE and the second base station indicates one of: an impairment of the communication path between the UE and the second base station; an obstacle between the UE and the second base station; a decrease in signal quality of the joint communications between the UE and the second base station; and a decrease in signal strength of the joint communications between the UE and the second base station.

6. The method as recited in claim 1, wherein: the selecting of the surface configuration for the APD further comprises selecting the surface configuration based on one of: a location of the UE; historical records indicative of use of the APD with the UE or other UEs proximate the location of the UE; and a change in the location of the UE.

7. The method as recited in claim 1, further comprising: selecting the APD from the one or more available APDs to include in the communication path between the UE and the second base station based on one of: a location of the UE; historical records indicative of use of the APD with the UE or other UEs proximate the location of the UE; and a change in the location of the UE.

8. The method as recited in claim 6 or claim 7, further comprising identifying the change in the location of the UE using a distance threshold value.

9. The method as recited in claim 1, further comprising: receiving a request from the second base station to coordinate the joint communications using the APD in the communication path between the UE and the second base station; and selecting the APD from the one or more available APDs to include in the communication path based on the request from the second base station.

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10. The method as recited in claim 1, further comprising: performing a beam-sweeping procedure to generate one or more measurements of the communication path between the UE and the second base station; and wherein: the selecting of the surface configuration for the APD uses the one or more measurements generated by the beam-sweeping procedure.

11. The method as recited in claim 1, further comprising: performing a beam-sweeping procedure to generate one or more measurements of the communication path between the UE and the second base station; and selecting the APD from the one or more available APDs to include in the communication path using the one or more measurements generated by the beam-sweeping procedure.

12. The method as recited in claim 11 , wherein the one or more measurements indicate that signal-related conditions of the communication path between the UE and the second base station are improved based on the APD being included in the communication path.

13. The method as recited in any one of claims 1 to 12, wherein the directing of the APD to apply the surface configuration further comprises: communicating the surface configuration for the APD to the second base station; and directing the second base station to communicate the surface configuration to the APD.

14. The method as recited in any one of claims 1 to 13, wherein the selecting of the surface configuration for the APD is based on a transmit diversity pattern for the joint communications.

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15. The method as recited in any of claims 1 to 14, wherein the selecting of the surface configuration for the APD further comprises: selecting, as the surface configuration, a downlink surface configuration for downlink communications from the second base station to the UE; and directing the APD to apply an uplink surface configuration for uplink communications from the UE to the second base station using channel reciprocity principles and the downlink surface configuration; or selecting, as the surface configuration, the uplink surface configuration for the uplink communications from the UE to the second base station; and directing the APD to apply the downlink surface configuration for the downlink communications from the second base station to the UE using the channel reciprocity principles and the uplink surface configuration.

16. The method as recited in any one of claims 1 to 15, wherein the coordinating of the joint communications comprises: communicating with the UE using a first multiple input, multiple output, MIMO, layer; and directing the second base station to communicate with the UE using a second MIMO layer.

17. The method as recited in claim 1, wherein a first communication path between the UE and the first base station includes the APD, the communication path between the UE and the second base station is a second communication path, and wherein the selecting of the surface configuration for the APD further comprises: selecting a first apportioned surface configuration that configures a first subset of configurable surface elements of a surface of the APD in the first communication path between the UE and the first base station; and selecting a second apportioned surface configuration that configures a second subset of the configurable surface elements of the surface of the APD in the second communication path between the UE and the second base station, wherein the directing of the APD to apply the surface configuration further comprises directing the APD to apply the first apportioned surface configuration and the second apportioned surface configuration.

18. An apparatus comprising: a wireless transceiver; a processor; and a computer-readable storage medium comprising instructions, when executed by the processor, direct the apparatus to carry out steps of the method as recited in any of claims 1 to 17.

19. A computer-readable storage medium comprising instructions, when executed by a processor, direct an apparatus to carry out steps of the method as recited in any of claims 1 to 17.