Enhanced beam search for active coordination sets

Abstract

This document describes methods, devices, systems, and apparatus for enhanced beam search for an active coordination set. A user device (110) receives an active coordination set beam scan (602) comprising a plurality of time slots (610), each of the plurality of time slots comprising one or more candidate beams. The user device (110) determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot. Based on the link quality metric, the user device (110) selects the one or more candidate beams in the time slot (610) for wireless communication. The user device (110) transmits a beam acquisition indication (620) at a first time offset (604) after the time slot (610) in which the selected one or more candidate beams are received, the transmission directing a base station (120) to use the selected one or more candidate beams for wireless communication.

Description

Background Art

[0001] The Active Coordination Set (ACS) of base stations provides and optimizes mobility management and other services to user equipment (UE) in the radio access network (RAN). The ACS can be a component of, or used to implement, a user-centric cell-free (UCNC) network architecture. As the UE moves within the coverage provided by the RAN, the UE continuously determines and updates which base stations are available for wireless communication from its perspective.

[0002] The evolution of wireless communication systems to fifth generation (5G) new radio (5G NR) and sixth generation (6G) technologies provides higher data rates to users. Higher data rates can still be provided at the edge of 5G and 6G cells by employing techniques such as coordinated multi-point (CoMP) or dual connectivity (DC) over beamformed radio connections within an ACS. However, identifying a satisfactory beam for communication between user equipment and a base station in an ACS becomes increasingly complex at higher radio frequencies that are more susceptible to blocking and for UEs that experience rapidly changing radio channel conditions. Summary of the invention

[0003] This summary is provided to introduce a simplified concept for enhanced beam search for active coordination sets. The simplified concept is further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used in determining the scope of the claimed subject matter.

[0004] In some aspects, a method for selecting, by a user device, a beam for wireless communication in an active coordination set is described, wherein the user device receives candidate beams of an active coordination set beam scan transmitted by a base station in the active coordination set, the active coordination set beam scan comprising a plurality of time slots, each of the plurality of time slots comprising one or more candidate beams. The base station transmits a plurality of candidate beams over time slots, such as consecutive time slots, to form an active coordination set beam scan. The user device determines a corresponding link quality metric for each of the one or more candidate beams received in each of the time slots, and based on the determined link quality metric, the user device selects the one or more candidate beams in the time slot for the wireless communication. The link quality metric may be determined and the one or more candidate beams may be selected by the user device, or if alternative wireless communication is available, the link quality metric and the selection of the one or more candidate beams may be determined by other network entities such as a base station or a core network. The user device transmits a beam acquisition indication at a first time offset after the time slot in which the selected one or more candidate beams are received, the transmission being effective to direct the base station to use the selected one or more candidate beams for wireless communication. The first time offset is preferably a fixed time offset or a predetermined time offset.Such an offset may be used such that the base station is configured at the time offset to receive the beam acquisition indication on the selected beam.

[0005] In another aspect, a method for selecting a beam for wireless communication in an active coordination set is described, wherein a base station negotiates parameters for active coordination set beam scanning with a user equipment. The base station negotiates parameters for active coordination set beam scanning with other base stations in the active coordination set. Based on the parameters negotiated with the user equipment and the other base stations, the base station transmits one or more candidate beams for the active coordination set beam scanning. The base station receives a beam acquisition indication from the user equipment at a first time offset after transmitting a specific candidate beam in the active coordination set beam scanning, and based on the received beam acquisition indication, communicates with the user equipment using the beam indicated by the beam acquisition indication. The first time offset is preferably a fixed time offset or a predetermined time offset. Such an offset can be used so that the base station is configured to receive the beam acquisition indication on the selected beam at the time offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various aspects of enhanced beam search for an active coordination set are described with reference to the following drawings. Like reference numerals are used throughout the drawings to reference similar features and components:

[0007] Figure 1 An example wireless network system is illustrated in which various aspects of enhanced beam searching for an active coordinating set may be implemented.

[0008] Figure 2 An example device diagram is illustrated in which various aspects of enhanced beam searching for an active coordination set may be implemented.

[0009] Figure 3 Air interface resources extending between a user equipment and a base station are illustrated and utilized to implement various aspects of enhanced beam searching for an active coordination set technique.

[0010] Figure 4 An example of a user equipment moving through a radio access network including multiple base stations in accordance with aspects of enhanced beam searching for an active coordinating set technique is illustrated.

[0011] Figure 5 An example environment is illustrated in which various aspects of enhanced beam searching for an active coordination set may be implemented.

[0012] Figure 6 An example timing diagram of beam searching between an active coordinating set and a user equipment in accordance with aspects of enhanced beam searching for an active coordinating set is illustrated.

[0013] Figure 7

[0013] Illustrated are example methods for enhanced beam search for an active coordination set, generally associated with a user equipment selecting a beam for downlink communications, in accordance with aspects of the enhanced beam search for an active coordination set.

[0014] Figure 8

[0026] Illustrated are example methods of enhanced beam search for an active coordinating set, generally associated with a user equipment selecting a beam for uplink communications, in accordance with aspects of the enhanced beam search for an active coordinating set.

[0015] Fig. 9

[0026] Example methods of enhanced beam searching for an active coordinating set are illustrated, generally in relation to a base station selecting a beam for downlink communications, in accordance with aspects of the enhanced beam searching for an active coordinating set.

[0016] Fig.10

[0026] Example methods for enhanced beam searching for an active coordinating set are illustrated, generally in relation to a base station selecting a beam for uplink communications, in accordance with aspects of the enhanced beam searching for an active coordinating set. DETAILED DESCRIPTION

[0017] This document describes methods, devices, systems, and apparatus for enhanced beam search for an active coordination set (ACS). A user equipment (UE) receives an active coordination set beam scan comprising a plurality of time slots, each of the plurality of time slots comprising one or more candidate beams. The user equipment determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot. Based on the link quality metric, the user equipment selects one or more candidate beams in the time slot for wireless communication. The user equipment transmits a beam acquisition indication at a first time offset after the time slot in which the selected one or more candidate beams are received, the transmission directing a base station to use the selected one or more candidate beams for wireless communication.

[0018] The evolution of wireless communication systems to fifth generation (5G) New Radio (5G NR) and sixth generation (6G) technologies provides higher data rates to users. Even higher data rates can be provided at the edge of 5G and 6G cells by employing techniques such as coordinated multi-point (CoMP) or dual connectivity (DC) over beamforming radio connections. However, identifying a satisfactory beam for communication between a user equipment (UE) and a base station in an ACS becomes increasingly complex at higher radio frequencies that are more susceptible to blockage and for UEs that experience rapidly changing radio channel conditions.

[0019] Conventional techniques for beam searching employ beam scanning during the UE's attach procedure, where periodic beam scanning updates are performed to identify a suitable beam for communication between the UE and the base station. These techniques are base station specific and do not fully consider the changing radio channel environment of user equipment communicating with multiple base stations in an ACS.

[0020] In various aspects, for enhanced beam searching of an active coordinating set, a base station in the ACS transmits an ACS beam scan on a downlink control channel. The ACS beam scan includes a number of time slots in which the base station in the ACS transmits candidate beams.

[0021] One or more base stations in the ACS transmit each candidate beam in the ACS beam scan using a different beam. The UE attempts to decode each candidate beam of the ACS beam scan. When the UE decodes the candidate beam and determines that the candidate beam will be satisfactory for communication, the UE transmits a beam acquisition indication (BAI) to the ACS in the uplink. The UE transmits the BAI at the first time offset after the UE receives the selected candidate beam. The BAI includes an identifier of the UE.

[0022] For downlink communications, the base station receiving the BAI uses the UE identifier and the timing of the received BAI to determine which beam to use for downlink data transmission, and transmits the downlink data on the data channel at a second time offset after the ACS receives the BAI. After receiving the downlink data, the UE transmits an acknowledgment to the ACS at a third time offset after receiving the downlink data.

[0023] For uplink communication, the UE transmits a BAI with uplink data at a first time offset after the UE receives the selected candidate beam. The UE uses the resources granted in the received resource grant to transmit the uplink data on the same physical channel as the downlink control channel or on a different physical channel. After transmitting the uplink data, the ACS or a base station in the ACS transmits a downlink acknowledgment to the UE at a fourth time offset after the ACS receives the uplink data.

[0024] While the features and concepts of the described systems and methods for enhanced beam search for an active coordination set can be implemented in many different environments, systems, devices, and / or various configurations, various aspects of the enhanced beam search for an active coordination set are described in the context of the following example devices, systems, and configurations.

[0025] Example Environment

[0026] Figure 1 An example environment 100 in which various aspects of enhanced beam search for an active coordination set can be implemented is illustrated. The example environment 100 includes a user equipment 110 (UE 110) communicating with one or more base stations 120 (illustrated as base stations 121 and 122) via one or more wireless communication links 130 (wireless links 130) illustrated as wireless links 131 and 132. In this example, the user equipment 110 is implemented as a smart phone. Although illustrated as a smart phone, the user equipment 110 can be implemented as any suitable computing or electronic device, such as a mobile communication device, a modem, a cellular phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a smart appliance, or a vehicle-based communication system. The base station 120 (e.g., an evolved universal terrestrial radio access network node B, an E-UTRAN node B, an evolved node B, an eNodeB, an eNB, a next generation node B, a gNode B, a gNB, a 6G node B, etc.) can be implemented in a macro cell, a micro cell, a small cell, a pico cell, etc., or any combination thereof.

[0027] The base station 120 communicates with the user equipment 110 via wireless links 131 and 132, which can be implemented as any suitable type of wireless links. The wireless links 131 and 132 can include downlinks of data and control information communicated from the base station 120 to the user equipment 110, uplinks of other data and control information communicated from the user equipment 110 to the base station 120, or both. The wireless link 130 may include one or more wireless links or bearers implemented using any suitable communication protocol or standard or a combination of communication protocols or standards such as the following: 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), Fifth Generation New Radio (5G NR), 6G, etc. Multiple wireless links 130 may be aggregated in carrier aggregation to provide higher data rates for the user equipment 110. Multiple wireless links 130 from multiple base stations 120 may be configured for coordinated multi-point (CoMP) communication with the user equipment 110. Additionally, the plurality of 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).

[0028] The base stations 120 are collectively referred to as a radio access network 140 (RAN, Evolved Universal Terrestrial Radio Access Network, E-UTRAN, 5G NR RAN, or NR RAN). The base stations 121 and 122 in the RAN 140 are connected to a core network 150, such as a fifth generation core (5GC) or a 6G core network. The base stations 121 and 122 are connected to the core network 150 at 102 and 104, respectively, via an NG2 interface (or a similar 6G interface) for control plane signaling and via an NG3 interface (or a similar 6G interface) for user plane data communication. In addition to the connection to the core network, the base stations 120 can also communicate with each other at 112 via an Xn Application Protocol (XnAP) to exchange user plane and control plane data. The user equipment 110 can also be connected to a public network such as the Internet 160 via the core network 150 to interact with a remote service 170.

[0029] Example Device

[0030] Figure 2 An example device diagram 200 illustrates user equipment 110 and base station 120. User equipment 110 and base station 120 may include for clarity Figure 2Additional functions and interfaces omitted. The user equipment 110 includes an antenna 202, a radio frequency front end 204 (RF front end 204), an LTE transceiver 206, a 5G NR transceiver 208, and a 6G transceiver 210 for communicating with the base station 120 in the RAN 140. The front end 204 of the user equipment 110 can couple or connect the LTE transceiver 206, the 5G NR transceiver 208, and the 6G transceiver 210 to the antenna 202 to facilitate various types of wireless communications. The antenna 202 of the user equipment 110 may include an array of multiple antennas configured similarly or differently to each other. The antenna 202 and the RF front end 204 can be tuned and / or tunable to one or more frequency bands defined by the 3GPP LTE, 5G NR, and 6G communication standards and implemented by the LTE transceiver 206, the 5G NR transceiver 208, and / or the 6G transceiver 210. Additionally, antenna 202, RF front end 204, LTE transceiver 206, 5G NR transceiver 208, and / or 6G transceiver 210 may be configured to support beamforming for transmission and reception of communications with base station 120. By way of example and not limitation, antenna 202 and RF front end 204 may be implemented to operate in sub-gigahertz bands, sub-6 GHZ bands, and / or above 6 GHz bands as defined by 3GPP LTE, 5G NR, and 6G communication standards.

[0031] The user equipment 110 also includes (multiple) processors 212 and computer readable storage media 214 (CRM214). The processor 212 can be a single-core processor or a multi-core processor composed of various materials such as silicon, polysilicon, high-K dielectrics, copper, etc. The computer-readable storage media described herein excludes propagation signals. The CRM 214 may include any suitable memory or storage device, such as a random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory that can be used to store device data 216 of the user equipment 110. The device data 216 includes user data, multimedia data, beamforming codebooks, applications, and / or operating systems of the user equipment 110, which can be executed by the (multiple) processors 212 to implement user plane communications, control plane signaling, and user interaction with the user equipment 110.

[0032] In some implementations, the CRM 214 may also include an active coordination set (ACS) manager 218. The ACS manager 218 can communicate with the antenna 202, the RF front end 204, the LTE transceiver 206, the 5G NR transceiver 208, and / or the 6G transceiver 210 to monitor the quality of the wireless communication link 130. Based on this monitoring, the ACS manager 218 can determine to add or remove a base station 120 from the ACS and / or determine a beam to use for communicating with a base station.

[0033] Figure 2 The device diagram of the base station 120 shown includes a single network node (e.g., gNode B). The functionality of the base station 120 can be distributed across multiple network nodes or devices and can be distributed in any manner suitable for performing the functions described herein. The base station 120 includes an antenna 252, a radio frequency front end 254 (RF front end 254), one or more LTE transceivers 256, one or more 5G NR transceivers 258, and / or one or more 6G transceivers 260 for communicating with the UE 110. The RF front end 254 of the base station 120 can couple or connect the LTE transceiver 256, the 5G NR transceiver 258, and / or the 6G transceiver 260 to the antenna 252 to facilitate various types of wireless communications. The antenna 252 of the base station 120 may include an array of multiple antennas configured similarly or differently to each other. The antenna 252 and the RF front end 254 can be tuned and / or tunable to one or more frequency bands defined by 3GPP LTE, 5G NR, and 6G communication standards and implemented by the LTE transceiver 256, one or more 5G NR transceivers 258, and / or one or more 6G transceivers 260. Additionally, the antenna 252, the RF front end 254, the LTE transceiver 256, the one or more 5G NR transceivers 258, and / or the one or more 6G transceivers 260 can be configured to support beamforming, such as massive MIMO, for transmission and reception of communications with the UE 110.

[0034] The base station 120 also includes a processor(s) 262 and a computer readable storage medium 264 (CRM 264). The processor 262 may be a single core processor or a multi-core processor composed of various materials such as silicon, polysilicon, high-K dielectrics, copper, etc. The CRM 264 may include any suitable memory or storage device, such as a random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory that can be used to store device data 266 of the base station 120. The device data 266 includes network scheduling data, radio resource management data, beamforming codebooks, applications, and / or operating systems of the base station 120, which can be executed by the processor(s) 262 to enable communication with the user equipment 110.

[0035] The CRM 264 also includes a base station manager 268. Alternatively or additionally, the base station manager 268 can be implemented in whole or in part as hardware logic or circuitry that is integrated with or separate from other components of the base station 120. In at least some aspects, the base station manager 268 configures the LTE transceiver 256, the 5G NR transceiver 258, and the 6G transceiver 260 for communication with the user equipment 110, and with a core network such as the core network 150, and routes user plane and control plane data for joint communication. Additionally, when the base station 120 is acting as a master base station for the base station 120 in the ACS, the base station manager 268 can allocate air interface resources, schedule communications, and perform beam scanning for the UE 110 and the base station 120 in the ACS.

[0036] The base station 120 includes an inter-base station interface 270, such as an Xn interface and / or an X2 interface, which the base station manager 268 configures to exchange user plane and control plane data between other base stations 120 to manage the communication of the base station 120 with the user equipment 110. The base station 120 includes a core network interface 272, which the base station manager 268 configures to exchange user plane and control plane data with core network functions and / or entities.

[0037] Figure 3 The air interface resources extending between the user equipment and the base station and capable of being used to implement various aspects of the enhanced beam search for the active coordination set are illustrated. The air interface resources 302 can be divided into resource units 304, each of which occupies some intersection of the spectrum and the elapsed time. A portion of the air interface resources 302 is graphically illustrated in a grid or matrix having a plurality of resource blocks 310 including example resource blocks 311, 312, 313, 314. The example of the resource unit 304 thus includes at least one resource block 310. As shown, time is depicted as the abscissa axis along the horizontal dimension, and frequency is depicted as the ordinate axis along the vertical dimension. The air interface resources 302 as defined by a given communication protocol or standard can span any suitable specified frequency range, and / or can be divided into intervals of any specified duration. The increment of time can correspond to, for example, milliseconds (mSec). The increment of frequency can correspond to, for example, megahertz (MHz).

[0038] Typically in example operation, the base station 120 allocates portions of the air interface resources 302 (e.g., resource elements 304) for uplink and downlink communications. Each resource block 310 of the network access resources can be allocated to support corresponding wireless communication links 130 of multiple user devices 110. In the lower left corner of the grid, the resource block 311 can span a specified frequency range 306 as defined by a given communication protocol and include multiple subcarriers or frequency subbands. The resource block 311 can include any suitable number of subcarriers (e.g., 12), each of which corresponds to a corresponding portion (e.g., 15 kHz) of the specified frequency range 306 (e.g., 180 kHz). The resource block 311 can also span a specified time interval 308 or time slot (e.g., lasting approximately one-half millisecond or seven orthogonal frequency division multiplexing (OFDM) symbols) as defined by a given communication protocol. The time interval 308 includes subintervals that can each correspond to a symbol (such as an OFDM symbol). As Figure 3 As shown, each resource block 310 may include a plurality of resource elements 320 (REs) corresponding to or defined by subcarriers of the frequency range 306 and subintervals (or symbols) of the time interval 308. Alternatively, a given resource element 320 may span more than one frequency subcarrier or symbol. Thus, a resource unit 304 may include at least one resource block 310, at least one resource element 320, and the like.

[0039] In an example implementation, a plurality of user devices 110 (one of which is shown) are communicating with a base station 120 (one of which is shown) via access provided by a portion of the air interface resources 302. The base station manager 268 (shown in Figure 2 The base station manager 268 may determine a corresponding data rate, type of information, or amount of information (e.g., data or control information) to be communicated (e.g., transmitted) by the user equipment 110. For example, the base station manager 268 may determine that each user equipment 110 will transmit at a different corresponding data rate or transmit a different corresponding amount of information. The base station manager 268 may then allocate one or more resource blocks 310 to each user equipment 110 based on the determined data rate or amount of information.

[0040] Additionally, or as an alternative to block-level resource grants, the base station manager 268 can allocate resource units at the element level. Thus, the base station manager 268 can allocate one or more resource elements 320 or individual subcarriers to different user equipment 110. By doing so, one resource block 310 can be allocated to facilitate network access for multiple user equipment 110. Thus, the base station manager 268 can allocate one or up to all subcarriers or resource elements 320 of a resource block 310 to one user equipment 110 or divide across multiple user equipment 110 at various granularities, thereby achieving higher network utilization or improved spectrum efficiency.

[0041] The base station manager 268 can thus allocate the air interface resources 302 by resource units 304, resource blocks 310, frequency carriers, time intervals, resource elements 320, frequency subcarriers, time subintervals, symbols, spreading codes, some combination thereof, etc. Based on the respective allocations of the resource units 304, the base station manager 268 can transmit respective messages to the plurality of user equipments 110 indicating the respective allocations of the resource units 304 to each user equipment 110. Each message can enable the respective user equipment 110 to queue information or configure the LTE transceiver 206, the 5G NR transceiver 208, and / or the 6G transceiver 210 to communicate via the allocated resource units 304 of the air interface resources 302.

[0042] Activity Coordination Set

[0043] Figure 4 An example environment 400 is illustrated in which a user equipment 110 is moving through a radio access network (RAN) including a plurality of base stations 120, illustrated as base stations 121-127. These base stations may utilize different technologies (e.g., LTE, 5G NR, 6G) at various frequencies (e.g., sub-gigahertz, sub-6 GHz, and above 6 GHz bands and sub-bands).

[0044] For example, user equipment 110 follows path 402 through RAN 140. User equipment 110 periodically measures link quality (e.g., link quality of base stations currently in the ACS and candidate base stations that UE 110 can add to the ACS). For example, at location 404, the ACS includes base stations 121, 122, and 123 at 406. As UE 110 continues to move, at location 408, UE 110 has deleted base stations 121 and 122 from the ACS and added base stations 124, 125, and 126, as shown at 410. Continuing along path 402, UE 110 has deleted base stations 123 and 124 at location 412 and added base station 127, as shown in the ACS at 414.

[0045] Figure 5An example environment 500 in which various aspects of enhanced beam search for an active coordination set can be implemented is illustrated. A user equipment 110 participates in joint transmission and / or reception (joint communication) with three base stations 121, 122, and 123. Base station 121 is acting as a master base station for joint transmission and / or reception. Which base station is the master base station is transparent to UE 110, and the master base station can change as base stations are added and / or removed from the ACS. The master base station coordinates control plane and user plane communications for joint communication of UE 110 with base stations 122 and 123 via Xn interface 112 (or a similar 6G interface), and maintains a user plane context between UE 110 and core network 150. Coordination can be performed using proprietary or standards-based messaging, procedures, and / or protocols.

[0046] The primary base station schedules air interface resources for joint communication between UE 110 and base stations 121, 122, and 123 based on the ACS associated with UE 110. The primary base station (base station 121) is connected to a user plane function 510 (UPF 510) in the core network 150 via an N3 interface 501 (or 6G equivalent interface) for user plane data communication to and from user equipment 110. The primary base station distributes user plane data to all base stations in joint communication via an Xn interface 112. UPF 510 is also connected to a data network such as the Internet 160 via an N6 interface 502.

[0047] UE 110 downlink data can be transmitted from all base stations 120 in the ACS or any subset of base stations 120 in the ACS. The master base station 121 determines which combination of base stations 120 in the ACS to use for transmitting downlink data to the UE 110. The selection of the base station 120 to be used for transmitting downlink data can be based on one or more factors, such as application quality of service (QoS) requirements, location of the UE 110, speed of the UE 110, reference signal received power (RSRP), received signal strength indicator (RSSI), interference, etc. UE 110 uplink data can be received by all base stations 120 in the ACS or any subset of base stations 120 in the ACS.

[0048] Similar to downlink data, the master base station 121 determines which combination of base stations 120 in the ACS to use for receiving uplink data from the UE 110. The selection of the base station 120 to use for receiving uplink data can be based on one or more factors, such as application QoS requirements, location of the UE 110, speed of the UE 110, RSRP, RSSI, interference, etc. Typically, the combination of base stations 120 used for downlink transmission and uplink reception will be the same, but different combinations of base stations 120 may be used for downlink transmission and uplink reception.

[0049] When the user equipment 110 creates or modifies an ACS, the user equipment 110 communicates the ACS or ACS modification to the ACS server 520, which stores the ACS for each user equipment 110 operating in the RAN 140. Although shown in the core network 150, the ACS server 520 may alternatively be an application server located outside the core network 150. The user equipment 110 communicates the ACS or ACS modification via a primary base station (base station 121), which is connected to the ACS server 520 via an N-ACS interface 503. Optionally or alternatively, the user equipment 110 communicates the ACS or ACS modification to the ACS server 520 via an access and mobility function 530 (AMF 530), which is connected to the primary base station (base station 121) via an N2 interface 504. The AMF 530 relays ACS-related communications to and from the ACS server 520 via an ACS-AMF interface 505. The ACS data between the user equipment 110 and the ACS server 520 can be communicated via Radio Resource Control (RRC) communication, Non-Access Stratum (NAS) communication, or Application Layer communication.

[0050] Enhanced beam search for active coordination sets

[0051] Figure 6 Example timing diagrams 600 and 650 of beam searching between an active coordinating set and a user equipment are illustrated in accordance with aspects of enhanced beam searching for an active coordinating set. Timing diagram 600 illustrates beam searching for transmitting downlink data to a UE, while timing diagram 650 illustrates beam searching for transmitting uplink data by a UE.

[0052] In one aspect, a base station in the ACS transmits an active coordination set beam scan 602 (ACS beam scan 602) on a downlink control channel. The ACS beam scan 602 includes a plurality of time slots 610 in which the base stations in the ACS transmit candidate beams. The ACS beam scan 602 is illustrated as including time slots 611, 612, and 613 to 619; however, the ACS beam scan 602 may include any suitable number of time slots 610. Each candidate beam transmitted in a time slot 610 may be individually decoded by the UE 110.

[0053] One or more base stations 120 (such as Figure 5 The base stations 121, 122, and 123 shown in FIG. 1 and 2) use different beams and transmit each candidate beam in the ACS beam scan on the same frequency. The master base station 121 determines which base stations in the ACS will transmit the frequency of the downlink control channel for the ACS beam scan 602 during the ACS beam scan 602 and the configuration of the transmission. The master base station 121 determines which base station or base stations will transmit during a given time slot 610 and the beam configuration transmitted by each base station. The master base station 121 uses the Xn interface 112 (or a similar 6G interface) to coordinate the ACS beam scan to other base stations in the ACS (e.g., base stations 122 and 123).

[0054] In an alternative aspect, the main base station 121 can configure a single base station in the ACS to transmit a candidate beam in each time slot 610 in the ACS beam scan 602; configure different base stations 120 in the ACS to transmit candidate beams in different time slots 610 in the ACS beam scan 602; or configure multiple base stations 120 in the ACS to concurrently transmit candidate beams in a single time slot 610, a portion of the time slots 610, or all the time slots 610 in the ACS beam scan 602.

[0055] The main base station 121 configures the parameters of each candidate beam transmitted by each base station. The main base station can specify the precoding matrix used by each base station for each candidate beam transmitted by the base station. The main base station 121 can specify the transmit power of each candidate beam transmitted by each base station. The main base station 121 configures the reference signal used to transmit each candidate beam. For example, if the goal of the beam search is to support diversity reception or coordinated multi-point (CoMP) communication of the UE, the main base station 121 configures multiple base stations to each transmit a candidate beam in the same time slot 610 and use the same pilot signal (e.g., reference signal, pilot sequence, demodulation reference signal (DM-RS)) to transmit the candidate beam. The main base station 121 can configure different base stations to transmit beam scanning in any suitable scanning direction (e.g., clockwise, counterclockwise), scanning speed, and starting from any suitable angle starting point.

[0056] For example, consider beam scanning for CoMP with joint transmission by three base stations. During beam scanning, the UE does not need to individually identify which of the three beams are received at the UE. The UE only needs to determine that any combination of one, two, or three beams it receives in a time slot is satisfactory for uplink or downlink communications. The decision at the UE does not depend on which beams the UE receives or does not receive. In this way, the UE does not need to distinguish different beams based on pilot signals (e.g., reference signals, pilot sequences, demodulation reference signals (DM-RS)). After receiving the beam acquisition indication (BAI) 620 of the selected (multiple) beams in the time slot based solely on receiving the beam acquisition indication (BAI) 620 at the first time offset, all three base stations transmit downlink data, regardless of whether the UE receives a particular beam from a particular base station during the selected time slot.

[0057] The (multiple) base stations in the ACS (e.g., the master base station 121) negotiate with the UE 110 to determine the configuration of the ACS beam scanning 602. The negotiation configures the number of time slots 610 in the ACS beam scanning 602 and / or the duration of the time slots 610. The negotiation includes the master base station providing an indication of the configuration (e.g., precoding matrix, reference signal, etc.) used by the UE 110 during the ACS beam scanning. The ACS negotiates with each UE individually in order to take into account the capabilities of each UE 110. For example, if the UE is capable of performing receiver beam scanning for each time slot 610, the negotiation can determine the duration of the time slot 610 to allow the UE 110 to perform receiver beam scanning during each time slot 610. The negotiation can be performed using an omni-directional beam or using an anchor carrier in a frequency band different from the frequency band used for the ACS beam scanning 602.

[0058] UE 110 decodes the candidate beams to determine which candidate beam will be satisfactory for communication. UE 110 may use any appropriate link quality metric to determine that a particular candidate beam will be satisfactory (e.g., a link quality metric value greater than a threshold for a received signal strength indicator (RSSI), a reference signal received power (RSRP), or a reference signal received quality (RSRQ)). UE 110 may evaluate the candidate beams received in all time slots 610 to find the candidate beam (or set of candidate beams in a particular time slot) with the best link quality metric before making a selection, or UE 110 may terminate evaluating the candidate beams upon determining the first satisfactory candidate beam (or set of candidate beams in a particular time slot). For example, as shown in timing diagram 600, user equipment 110 selects a candidate beam (or set of candidate beams) transmitted in time slot 612 for communication. The pilot signal in each beam of a candidate beam set in a given time slot may be the same pilot signal or a different pilot signal.

[0059] To indicate a selected candidate beam for downlink data transmission (e.g., a candidate beam transmitted in time slot 612), UE 110 transmits a beam acquisition indication (BAI) 620 at a first time offset (t0) 604 after UE 110 receives the selected candidate beam. Although the first time offset is shown as starting at the end of time slot 612 for the selected candidate beam, any suitable fixed time offset may be used, such as the first time offset starting at the beginning of time slot 612. The base station(s) in the ACS transmitting the ACS beam scan 602 configures a reciprocal receive beam corresponding to each of the one or more beams transmitted in the ACS beam scan 602 to receive the beam acquisition indication 620 at a time offset equal to the first time offset 604 for each candidate beam transmitted in the ACS beam scan 602.

[0060] The air interface resources for BAI 620 are granted by the ACS (e.g., the primary base station 121) and may be granted during negotiation. BAI 620 may be transmitted as a control plane message or as one or more pilot symbols. BAI 620 includes an identifier of UE 110. The combination of the UE identifier and the timing of BAI 620 indicates to the ACS which beams of the candidate beams transmitted during the ACS beam scanning 602 are used to transmit downlink data to UE 110. The base station in the ACS transmits downlink data 622 using the selected candidate beam at a second time offset (t1) 606 after the ACS receives the BAI 620. Alternatively or additionally, the base station in the ACS may further refine the selected beam for transmitting downlink data. After receiving the downlink data, UE 110 transmits an uplink confirmation 624 to the base station in the ACS at a third time offset (t2) 608 after UE 110 receives the downlink data. The uplink acknowledgement may be a positive acknowledgement (ACK) if UE 110 successfully decoded the downlink data, or a negative acknowledgement (NACK) if UE 110 did not successfully decode the downlink data.

[0061] To select a beam for uplink data transmission, as shown in timing diagram 650, a base station in the ACS transmits an ACS beam scan 602 on a downlink control channel, as described above. Air interface resource grants for uplink communication may be included in the ACS beam scan 602, may be communicated during negotiation, or may be transmitted separately to the UE 110. The UE 110 receives and decodes the candidate beams, as described above, and determines that one of the candidate beams (or candidate beam sets) transmitted in time slot 610 is for uplink communication. For example, the UE 110 decodes the candidate beam (or candidate beam set) transmitted in time slot 612 and determines that the candidate beam transmitted in time slot 612 will be satisfactory for uplink communication. To indicate the selected candidate beam for uplink data transmission, the UE 110 transmits a BAI with uplink data 652 at a first time offset (t0) 604 after the UE 110 receives the selected candidate beam. UE 110 transmits uplink data on the same physical channel as the downlink control channel or on a different physical channel using the resources granted in the received resource grant. After transmitting the uplink data, one or more base stations in the ACS transmit a downlink acknowledgment 654 to UE 110 at a fourth time offset (t3) at 656 after the base station in the ACS receives the uplink data. The downlink acknowledgment may be a positive acknowledgment (ACK) if the one or more base stations in the ACS successfully decoded the uplink data, or a negative acknowledgment (NACK) if the base station in the ACS did not successfully decode the uplink data.

[0062] The time offsets (t0, t1, t2, and / or t3) may be fixed time offsets, or predetermined time offsets, or may be negotiated between the primary base station and the UE as part of the negotiation of the configuration of the ACS beam scanning 602. For example, during the negotiation, the value of the time offset may be based on the capabilities of the user equipment.

[0063] Example Method

[0064] According to one or more aspects of enhanced beam search for an active coordination set, reference Figure 7-10Example methods 700-1000 are described. The order in which the method boxes are described is not intended to be interpreted as a limitation, and any number of the described method boxes 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 circuits), manual processing, or any combination thereof. Some operations of the example methods can be described in the general context of executable instructions stored on a computer-readable storage memory locally and / or remotely of a computer processing system, and implementations can include software applications, programs, functions, etc. 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, but not limited to, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a system on a chip (SoC), a complex programmable logic device (CPLD), etc.

[0065] Figure 7 Illustrated are (multiple) example methods 700 for enhanced beam search for an active coordination set as generally associated with a user device 110 selecting a beam for downlink communication. At block 702, the user device receives candidate beams for an active coordination set beam scan transmitted by a base station in the active coordination set, the active coordination set beam scan comprising a plurality of time slots, each of the plurality of time slots comprising one or more candidate beams. For example, a user device (e.g., user device 110) receives candidate beams for an active coordination set beam scan (e.g., ACS beam scan 602) from one or more base stations (e.g., base stations 121, 122, and / or 123) in the active coordination set. The ACS beam scan comprises a plurality of time slots, and each of the plurality of time slots comprises one or more candidate beams.

[0066] At block 704, the user device determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot. For example, the user device determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot, such as a received signal strength indicator (RSSI), a reference signal received power (RSRP), or a reference signal received quality (RSRQ).

[0067] At block 706, based on the determined link quality metric, the user equipment selects one or more candidate beams in the time slot for downlink communication. For example, based on the determined link quality metric, the user equipment selects the first one or more candidate beams in the time slot having a link quality metric greater than a minimum threshold of the link quality metric, or selects one or more candidate beams in the time slot having the best value of the link quality metric for downlink communication.

[0068] At block 708, the user device transmits a beam acquisition indication at a first time offset after receiving the time slot of the selected one or more candidate beams, the transmission being effective to direct the base station to use the selected one or more candidate beams for wireless communication. For example, the user device transmits a beam acquisition indication (e.g., beam acquisition indication 620) at a first time offset (e.g., first time offset 604) after receiving the time slot of the selected one or more candidate beams, the transmission being effective to direct the base station to use the selected one or more candidate beams for wireless communication. The time at which the base station receives the beam acquisition indication is used by the base station to determine which candidate beam or beams to select. The BAI may also include an identifier of the user device to indicate that the received BAI corresponds to an ACS beam scan transmitted to the user device.

[0069] At block 710, the user equipment receives downlink data from the base station using the selected one or more candidate beams at a second time offset after transmitting the beam acquisition indication. For example, the user equipment receives downlink data (e.g., downlink data 622) from the base station using the selected one or more candidate beams at a second time offset (e.g., second time offset 606) after transmitting the beam acquisition indication.

[0070] At block 712, in response to receiving the downlink data, the user equipment transmits an uplink confirmation at a third time offset after the received downlink data. For example, in response to receiving the downlink data, the user equipment transmits an uplink confirmation (e.g., uplink confirmation 624) at a third time offset (e.g., third time offset 608) after the received downlink data.

[0071] Figure 8 Example method(s) 800 for enhanced beam search for an active coordination set as generally related to a user device 110 selecting a beam for uplink communication are illustrated. At block 802, the user device receives candidate beams for an active coordination set beam scan transmitted by a base station in the active coordination set, the active coordination set beam scan comprising a plurality of time slots, each of the plurality of time slots comprising one or more candidate beams. For example, a user device (e.g., user device 110) receives candidate beams for an active coordination set beam scan (e.g., ACS beam scan 602) from one or more base stations (e.g., base stations 121, 122, and / or 123) in the active coordination set. The ACS beam scan comprises a plurality of time slots, and each of the plurality of time slots comprises one or more candidate beams.

[0072] At block 804, the user device determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot. For example, the user device determines a corresponding link quality metric for each of the one or more candidate beams received in each time slot, such as a received signal strength indicator (RSSI), a reference signal received power (RSRP), or a reference signal received quality (RSRQ).

[0073] At block 806, based on the determined link quality metric, the user equipment selects one or more candidate beams in the time slot for uplink communication. For example, based on the determined link quality metric, the user equipment selects the first one or more candidate beams in the time slot having a link quality metric greater than a minimum threshold of the link quality metric, or selects one or more candidate beams in the time slot having the best value of the link quality metric for uplink communication.

[0074] At block 808, the user equipment transmits a beam acquisition indication and uplink data at a first time offset after receiving the time slot of the selected one or more candidate beams, the transmission effectively directing the base station to use the selected candidate beam for uplink communication. For example, the user equipment transmits a beam acquisition indication and uplink data (e.g., beam acquisition indication and uplink data 652) at a first time offset (e.g., first time offset 604) after receiving the time slot of the selected candidate beam to direct the base station to use the selected candidate beam for uplink communication. The time at which the base station receives the beam acquisition indication is used by the base station to determine which beam to select. The BAI may also include an identifier of the user equipment to indicate that the received BAI corresponds to an ACS beam scan transmitted to the user equipment. The uplink data may be transmitted on the same channel as the BAI or on a different channel.

[0075] At block 810, based on transmitting the uplink data, the user equipment receives a downlink confirmation at a fourth time offset after transmitting the beam acquisition indication and the uplink data. For example, based on transmitting the uplink data, the user equipment receives a downlink confirmation (e.g., downlink confirmation 654) at a fourth time offset (e.g., fourth time offset 656) after transmitting the beam acquisition indication and the uplink data.

[0076] Fig. 9Illustrated are (multiple) example methods 900 for enhanced beam search for an active coordination set as generally related to a base station selecting a beam for downlink communication. At block 902, a base station negotiates parameters for active coordination set beam scanning with a user equipment. For example, a base station (e.g., a master base station 121) negotiates parameters for active coordination set beam scanning (e.g., ACS beam scanning 602) with a user equipment (e.g., user equipment 110). The negotiation may be performed using an omni-directional beam from a base station or using an anchor channel in a different frequency band.

[0077] At block 904, the base station negotiates parameters for active coordination set beam scanning with other base stations. For example, the base station negotiates parameters for active coordination set beam scanning with other base stations (e.g., base stations 122 and 123). The negotiation may be performed using an Xn interface (e.g., Xn interface 112) to coordinate the air interface for ACS beam scanning, the timing of coordinated transmissions for ACS beam scanning, etc.

[0078] At block 906, based on the negotiated parameters, the base station transmits one or more candidate beams for an active coordination set beam scan using one or more associated beams, which directs the user equipment to select a beam for downlink communication. For example, the base station transmits one or more beam packets (e.g., beam packet 610) for an active coordination set beam scan using one or more associated beams, which directs the user equipment to select a beam for downlink communication. The base station determines the duration of the beam packet based on the capabilities of the user equipment determined during the negotiation. Additional base stations in the ACS may also transmit one or more beam packets during the active coordination set beam scan.

[0079] At block 908, the base station receives a beam acquisition indication from the user equipment at a first time offset after transmitting a particular candidate beam in an active coordination set beam scan. For example, the base station receives the beam acquisition indication and uplink data (e.g., beam acquisition indication 620) at a first time offset (e.g., first time offset 604) after one of a plurality of beam groups indicating a selected beam for downlink communication (e.g., beam group 612). The time at which the beam acquisition indication is received enables the base station to determine which beam to select. The BAI may also include an identifier of the user equipment to indicate that the received BAI corresponds to an ACS beam scan transmitted to the user equipment.

[0080] At block 910, the base station transmits downlink data to the user equipment using the indicated beam at a second time offset after receiving the beam acquisition indication. For example, the base station transmits downlink data (e.g., downlink data 622) to the user equipment using the indicated beam at a second time offset (e.g., second time offset 606) after receiving the beam acquisition indication.

[0081] At block 912, the base station receives an uplink confirmation at a third time offset after transmitting the downlink data. For example, the base station receives an uplink confirmation (e.g., uplink confirmation 624) at a third time offset (e.g., third time offset 606) after transmitting the downlink data.

[0082] Fig.10 Illustrated are (multiple) example methods 1000 for enhanced beam search for an active coordination set as generally related to a base station selecting a beam for uplink communication. At block 1002, a base station negotiates parameters for active coordination set beam scanning with a user equipment. For example, a base station (e.g., a master base station 121) negotiates parameters for active coordination set beam scanning (e.g., ACS beam scanning 602) with a user equipment (e.g., user equipment 110). The negotiation may be performed using an omni-directional beam from a base station or using an anchor channel in a different frequency band.

[0083] At block 1004, the base station negotiates parameters for active coordination set beam scanning with other base stations. For example, the base station negotiates parameters for active coordination set beam scanning with other base stations (e.g., base stations 122 and 123). The negotiation may be performed using an Xn interface (e.g., Xn interface 112) to coordinate the air interface for ACS beam scanning, the timing of coordinated transmissions for ACS beam scanning, etc.

[0084] At block 1006, based on the negotiated parameters, the base station transmits one or more candidate beams for an active coordination set beam scan. For example, the base station determines the duration of a time slot (e.g., time slot 610) in which the base station transmits the candidate beams based on the capabilities of the user equipment determined during the negotiation. Additional base stations in the ACS may also transmit one or more candidate beams during an active coordination set beam scan as coordinated during the negotiation with the additional base stations.

[0085] At block 1008, the base station receives a beam acquisition indication and uplink data at a first time offset after transmitting a particular candidate beam in an active coordination set beam scan. For example, the base station receives a beam acquisition indication and uplink data (e.g., beam acquisition indication and uplink data 652) at a first time offset (e.g., first time offset 604) after transmitting the selected candidate beam, which indicates the candidate beam selected by the user equipment for uplink communication. The BAI may also include an identifier of the user equipment to indicate that the received BAI corresponds to an ACS beam scan transmitted to the user equipment. The uplink data may be transmitted on the same channel as the BAI or on a different channel.

[0086] At block 1010, in response to receiving the uplink data, the base station transmits a downlink confirmation at a fourth time offset after receiving the beam acquisition indication and the uplink data. For example, the base station transmits the downlink data to the user equipment using the indicated beam at a second time offset after receiving the beam acquisition indication. For example, in response to receiving the uplink data, the base station transmits a downlink confirmation (e.g., downlink confirmation 654) at a fourth time offset (e.g., fourth time offset 656) after receiving the beam acquisition indication and the uplink data.

[0087] Some examples are described in the following text:

[0088] Example 1: A method for selecting a beam for wireless communication in an active coordination set by a user equipment, the method comprising the user equipment: receiving a candidate beam of an active coordination set beam scan transmitted by a base station in the active coordination set, the active coordination set beam scan comprising a plurality of time slots, each of the plurality of time slots comprising one or more candidate beams; determining a corresponding link quality metric for each of the one or more candidate beams received in each of the time slots; based on the determined link quality metric, selecting the one or more candidate beams in the time slot for the wireless communication; and transmitting a beam acquisition indication at a first time offset after the time slot in which the selected one or more candidate beams are received, the transmission effectively directing the base station to use the selected one or more candidate beams for the wireless communication.

[0089] Example 2: The method of Example 1, wherein the wireless communication is a downlink communication, the method comprising the user equipment:

[0090] receiving downlink data from one or more of the base stations using the selected one or more candidate beams at a second time offset after transmitting the beam acquisition indication; and

[0091] In response to receiving the downlink data, an uplink acknowledgement is transmitted at a third time offset after the received downlink data.

[0092] Example 3: The method of Example 1, wherein the wireless communication is uplink communication, and wherein transmitting the beam acquisition indication comprises transmitting uplink data, the method comprising the user equipment:

[0093] Based on transmitting the uplink data, a downlink acknowledgement is received at a fourth time offset after transmitting the beam acquisition indication.

[0094] Example 4: The method of any of the preceding examples, wherein the link quality metric is:

[0095] received signal strength indicator;

[0096] reference signal received power; or

[0097] Reference signal reception quality.

[0098] Example 5: The method of any of the preceding examples, wherein selecting the one or more candidate beams comprises the user equipment:

[0099] The one or more candidate beams in a first time slot are selected in which the one or more candidate beams exceed a threshold value of the link quality metric.

[0100] Example 6: The method according to any one of claims 1 to 4, wherein the selecting a candidate beam comprises the user equipment:

[0101] The one or more candidate beams in a time slot are selected in which the one or more candidate beams have the best link quality metric of any of the candidate beams in the time slot.

[0102] Example 7: The method according to any one of the preceding examples, further comprising the user equipment:

[0103] Parameters for the active coordinating set beam scanning are negotiated with one or more base stations in the active coordinating set.

[0104] Example 8: The method of Example 7, wherein negotiating parameters for the active coordinating set beam scanning comprises determining a duration of the time slot, and wherein the duration of the time slot is determined based on one or more capabilities of the user equipment.

[0105] Example 9: The method of Example 7, wherein the parameter is negotiated using an omni-directional beam for communication between one or more base stations in the active coordinating set and the user equipment.

[0106] Example 10: The method of Example 7, wherein the parameter is negotiated using an anchor carrier used for communication between one or more base stations in the active coordinating set and the user equipment.

[0107] Example 11: The method of any of the preceding examples, wherein receiving the candidate beam comprises:

[0108] Candidate beams are received during a particular time slot, each of the candidate beams including a pilot sequence different from pilot sequences included in other candidate beams in the particular time slot.

[0109] Example 12: A user device comprising:

[0110] Wireless transceiver;

[0111] Processor; and

[0112] Instructions for an active coordination set manager, the instructions being executable by a processor to configure the user equipment to perform any one of Examples 1 to 11.

[0113] Example 13: A method of selecting a beam for wireless communication in an active coordination set, the method comprising a base station:

[0114] Negotiating with the user equipment parameters for active coordination set beam scanning;

[0115] Negotiating with other base stations in the active coordination set parameters for beam scanning of the active coordination set;

[0116] transmitting one or more candidate beams for the active coordination set beam scanning based on negotiating the parameters with the user equipment and the other base stations;

[0117] receiving a beam acquisition indication from the user equipment at a first time offset after transmitting a particular candidate beam in the active coordinating set beam scan; and

[0118] Based on the received beam acquisition indication, communicate with the user equipment using the beam indicated by the beam acquisition indication.

[0119] Example 14: The method of Example 13, wherein the wireless communication is a downlink communication, the method comprising the base station:

[0120] transmitting downlink data to the user equipment using the indicated beam at a second time offset after receiving the beam acquisition indication; and

[0121] In response to transmitting the downlink data, an uplink acknowledgement is received at a third time offset after transmitting the downlink data.

[0122] Example 15: The method of Example 13, wherein the wireless communication is uplink communication, and wherein receiving the beam acquisition indication comprises receiving uplink data, the method comprising the base station:

[0123] In response to receiving the uplink data, a downlink acknowledgement is transmitted at a fourth time offset after receiving the beam acquisition indication.

[0124] Example 16: The method according to Example 15, further comprising a base station:

[0125] Resources are granted to the user equipment to transmit the uplink data.

[0126] Example 17: The method according to any one of Examples 13 to 16, further comprising a base station:

[0127] The first time offset is used to determine which of the one or more beams transmitted during the active coordinating set beam scan to use for communications with the user equipment.

[0128] Example 18: The method of any one of Examples 13 to 17, wherein receiving the beam acquisition indication comprises the base station:

[0129] A reciprocal receive beam corresponding to each of the one or more candidate beams transmitted in the active coordination set beam scan is configured to enable the base station to receive the beam acquisition indication at a time offset equal to the first time offset for each of the candidate beams transmitted in the active coordination set beam scan.

[0130] Example 19: A method according to any one of Examples 13 to 18, wherein negotiating the parameters for the active coordination set beam scanning includes determining the duration of a time slot in the active coordination set beam scanning, and wherein the duration of the time slot is determined based on one or more capabilities of the user equipment.

[0131] Example 20: The method of any one of Examples 13 to 19, wherein the negotiation is performed using an omni-directional beam for communication between one or more base stations in the active coordination set and the user equipment.

[0132] Example 21: A method according to any one of Examples 13 to 20, wherein the negotiation is performed using an anchor carrier used for communication between one or more base stations in the active coordination set and the user equipment.

[0133] Example 22: A base station comprising:

[0134] Wireless transceiver;

[0135] Processor; and

[0136] Instructions for a base station manager, the instructions being executable by the processor to configure the base station to perform any of the methods described in Examples 13 to 21.

[0137] Although various aspects of enhanced beam search for active coordination sets have been described in language specific to features and / or methods, the subject matter 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 enhanced beam search for active coordination sets, and other equivalent features and methods are intended to be within the scope of the appended claims. Additionally, various different aspects are described, and it should be appreciated that each described aspect can be implemented independently or in conjunction with one or more other described aspects.

Claims

1. A method for selecting, by a user equipment, a beam for wireless communication in an active coordinated set comprising a plurality of base stations, the method comprising: receiving a candidate beam of an active coordination set beam scan transmitted by the base station in the active coordination set, the active coordination set beam scan comprising a plurality of time slots, each time slot of the plurality of time slots comprising one or more candidate beams; determining a corresponding link quality metric for each of the one or more candidate beams received in each time slot of the plurality of time slots; selecting the one or more candidate beams in a time slot for use in the wireless communication based on the determined link quality metric; as well as Transmitting a beam acquisition indication at a first predetermined time offset after a time slot in which the selected one or more candidate beams are received, wherein transmitting the beam acquisition indication effectively directs the base station to use the selected one or more candidate beams for the wireless communication, wherein the beam acquisition indication effectively allows the base station to determine which of the one or more candidate beams is selected based on the first predetermined time offset and the time when the base station receives the beam acquisition indication.

2. The method according to claim 1, wherein: The wireless communication is a downlink communication, and the method comprises: receiving downlink data from one or more of the base stations using the selected one or more candidate beams at a second time offset after transmitting the beam acquisition indication; and In response to receiving the downlink data, an uplink acknowledgement is transmitted at a third time offset after the received downlink data.

3. The method according to claim 1, wherein: The wireless communication is uplink communication, and wherein transmitting the beam acquisition indication comprises transmitting uplink data, the method comprising: Based on transmitting the uplink data, a downlink acknowledgement is received at a fourth time offset after transmitting the beam acquisition indication.

4. The method according to claim 1, wherein: The link quality metric is: received signal strength indicator; reference signal received power; or Reference signal reception quality.

5. The method according to claim 1, wherein: Selecting the one or more candidate beams comprises: The one or more candidate beams in a first time slot are selected in which the one or more candidate beams exceed a threshold value of the link quality metric.

6. The method according to claim 1, wherein: Selecting the one or more candidate beams comprises: The one or more candidate beams in a time slot are selected in which the one or more candidate beams have the best link quality metric of any of the candidate beams in the time slot.

7. The method according to claim 1, further comprising: Parameters for the active coordinating set beam scanning are negotiated with one or more base stations in the active coordinating set.

8. The method according to claim 7, wherein: Negotiating the parameters for the active coordinating set beam scanning includes determining a duration of the time slot, and wherein the duration of the time slot is determined based on one or more capabilities of the user equipment.

9. The method according to any one of claims 1 to 8, wherein: Receiving the candidate beam includes: The candidate beams are received during a particular time slot, each of the candidate beams including a pilot sequence different from pilot sequences included in other candidate beams in the particular time slot.

10. A user equipment, comprising: Wireless transceiver; processor; as well as Instructions for an active coordination set manager, the instructions being executable by the processor to configure the user equipment to perform the method according to any one of claims 1 to 9.

11. A method of selecting a beam for wireless communication in an active coordinating set comprising a plurality of base stations, the method being performed by a base station in the active coordinating set and comprising: Negotiating with the user equipment parameters for active coordination set beam scanning; Negotiate the parameters for beam scanning of the active coordination set with other base stations in the active coordination set; transmitting one or more candidate beams for the active coordination set beam scanning based on negotiating the parameters with the user equipment and the other base stations; receiving a beam acquisition indication from the user equipment at a first predetermined time offset after transmitting a particular candidate beam in the active coordination set beam scan; determining which candidate beam of the one or more candidate beams is selected based on the first predetermined time offset and a time at which the base station receives the beam acquisition indication; as well as Based on the determination, the selected candidate beam is used to communicate with the user equipment.

12. The method according to claim 11, wherein: The wireless communication is a downlink communication, and the method comprises: transmitting downlink data to the user equipment using the selected candidate beam at a second time offset after receiving the beam acquisition indication; and In response to transmitting the downlink data, an uplink acknowledgement is received at a third time offset after transmitting the downlink data.

13. The method according to claim 11, wherein: The wireless communication is uplink communication, and wherein receiving the beam acquisition indication comprises receiving uplink data, the method comprising: In response to receiving the uplink data, a downlink acknowledgement is transmitted at a fourth time offset after receiving the beam acquisition indication.

14. The method according to claim 13, further comprising: Resources are granted to the user equipment to transmit the uplink data.

15. The method according to any one of claims 11 to 14, further comprising: The first time offset is used to determine which of the one or more beams transmitted during the active coordinating set beam scan to use for communications with the user equipment.

16. The method according to claim 11, wherein: Receiving the beam acquisition indication includes: A reciprocal receive beam corresponding to each of the one or more candidate beams transmitted in the active coordination set beam scan is configured to enable the base station to receive the beam acquisition indication at a time offset equal to the first time offset for each of the candidate beams transmitted in the active coordination set beam scan.

17. The method according to claim 11, wherein: Negotiating the parameters for the active coordinating set beam scanning includes determining a duration of a time slot in the active coordinating set beam scanning, and wherein the duration of the time slot is determined based on one or more capabilities of the user equipment.

18. The method according to claim 11, wherein: The negotiation is performed using an omni-directional beam for communication between one or more base stations in the active coordinating set and the user equipment.

19. The method according to claim 11, wherein: The negotiation is performed using an anchor carrier used for communication between one or more base stations in the active coordinating set and the user equipment.

20. A base station, comprising: Wireless transceiver; processor; as well as Instructions for a base station manager, the instructions being executable by the processor to configure the base station to perform the method according to any one of claims 11 to 19.

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