Method and apparatus for dynamic antenna array reconfiguration and signaling in millimeter wave bands

Abstract

The invention relates to dynamic antenna array reconfiguration and signaling in millimeter wave bands. A user equipment (UE) may detect an antenna array change condition. The UE may send a request for beam training for the antenna array configuration in response to the detection. The request for beam training may include a requested antenna array configuration for the UE, and an indication of beam weights used with the requested antenna array configuration. The base station may determine whether to grant or reject the requested antenna array configuration for the UE. The UE may receive, from a base station, an indication of an antenna array configuration for the UE. A base station may transmit a number of reference signals as a set of consecutive channel state information reference signals (CSI-RSs). The UE may train the reconfigured active antenna array configuration based on the reference signal.

Description

[0001] This application is a divisional application of the application filed on April 14, 2022, with application number 202080072213.9 and invention name “Method and device for dynamic antenna array reconfiguration and signaling in millimeter wave frequency band”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application Serial No. 62 / 930,409, filed on November 4, 2019, entitled “METHODS AND APPARATUSES FOR DYNAMIC ANTENNA ARRAY RECONFIGURATION AND SIGNALING IN MILLIMETER WAVE BANDS,” and U.S. Patent Application No. 17 / 087,410, filed on November 2, 2020, entitled “METHODS AND APPARATUSES FOR DYNAMIC ANTENNA ARRAY RECONFIGURATION AND SIGNALING IN MILLIMETER WAVE BANDS,” which have been assigned to the assignee of this application and are incorporated herein by reference in their entirety. Technical Field

[0004] The present disclosure relates generally to communication systems, and in particular, to dynamic antenna array reconfiguration and signaling in millimeter wave frequency bands. Background Art

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that are capable of supporting communications with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional and even global levels. An example of a telecommunication standard is 5G New Radio (NR). 5GNR is part of the continuous mobile broadband evolution released by the Third Generation Partnership Project (3GPP) to meet new requirements related to latency, reliability, security, scalability (e.g., Internet of Things (IoT)) and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC) and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0007] A brief summary of one or more aspects is presented below to provide a basic understanding of these aspects. This summary is not an extensive overview of all anticipated aspects, and is neither intended to identify key or important elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that is presented later.

[0008] In one aspect of the present disclosure, a method, computer readable medium, and apparatus (e.g., user equipment (UE)) are provided. The method may include detecting an antenna array change condition at the UE. The method may include sending a request for beam training for an antenna array configuration from the UE in response to the detection. The method may include receiving an indication of an antenna array configuration for the UE from a base station.

[0009] In one aspect, the present disclosure provides an apparatus for wireless communication. The apparatus may include a memory, and at least one processor coupled to the memory. The processor may be configured to detect an antenna array change condition at a UE. The processor may be configured to send a request for beam training for antenna array configuration from the UE in response to the detection. The processor may be configured to receive an indication of an antenna array configuration for the UE from a base station.

[0010] In another aspect, the present disclosure provides an apparatus for wireless communication. The apparatus may include means for detecting an antenna array change condition at the UE. The apparatus may include means for sending a request for beam training for antenna array configuration from the UE in response to the detection. The apparatus may include means for receiving an indication of an antenna array configuration for the UE from a base station.

[0011] On the other hand, the present disclosure provides a non-transitory computer-readable medium storing computer-executable code, which, when executed by a processor, causes the processor to perform the following operations: detecting an antenna array change condition at a UE; sending a request for beam training for antenna array configuration from the UE in response to the detection; and receiving an indication of the antenna array configuration for the UE from a base station.

[0012] The antenna array change condition may be based on an angular spread of a primary cluster and a secondary primary cluster in a channel between the base station and the UE.

[0013] The antenna array change condition may be based on power considerations of the UE.

[0014] The antenna array change condition may be based on thermal considerations of the UE.

[0015] The antenna array change condition may be based on support for additional radio frequency chains utilizing a hybrid beamforming architecture.

[0016] The request for beam training may include a request to change an active antenna array configuration of the UE to a requested antenna array configuration.

[0017] The request for beam training may include an indication of beam weights to be used with the requested antenna array configuration.

[0018] The indication of the beam weight may be a pointer to an analog beamforming codebook index.

[0019] The indication of the antenna array configuration for the UE may indicate the requested antenna array configuration and a number of reference signals to be used for beam training with respect to the requested antenna array configuration.

[0020] The method of wireless communication may also include: configuring the antenna array based on the requested antenna array configuration to activate a reconfigured active antenna array configuration; training the reconfigured active antenna array configuration based on the reference signal; and sending a set of reference signal received power (RSRP) and associated beam indexes to the base station.

[0021] The indication of the antenna array configuration for the UE may indicate the active antenna array configuration.

[0022] In one aspect of the present disclosure, a method, computer readable medium, and apparatus (e.g., a base station) are provided. The method may include receiving, at a base station, from a UE a request for beam training for a requested antenna array configuration. The method may include determining whether to grant or deny the requested antenna array configuration. The method may include sending, from a base station, an indication of an antenna array configuration for the UE.

[0023] In one aspect, the present disclosure provides an apparatus for wireless communication. The apparatus may include a memory, and at least one processor coupled to the memory. The processor may be configured to receive, at a base station, from a UE a request for beam training for a requested antenna array configuration. The processor may be configured to determine whether to grant or deny the requested antenna array configuration. The processor may be configured to send an indication of an antenna array configuration for the UE from a base station.

[0024] In another aspect, the present disclosure provides an apparatus for wireless communication. The apparatus may include means for receiving, at a base station, from a UE, a request for beam training for a requested antenna array configuration. The apparatus may include means for determining whether to grant or deny the requested antenna array configuration. The apparatus may include means for sending, from a base station, an indication of an antenna array configuration for the UE.

[0025] On the other hand, the present disclosure provides a non-transitory computer-readable medium storing computer-executable code, which, when executed by a processor, causes the processor to perform the following operations: receiving a request for beam training for a requested antenna array configuration from a UE at a base station; determining whether to grant or deny the requested antenna array configuration; and sending an indication of the antenna array configuration for the UE from the base station.

[0026] The request for beam training may indicate support for additional radio frequency chains utilizing a hybrid beamforming architecture.

[0027] The request for beam training may include an indication of beam weights to be used with the requested antenna array configuration.

[0028] The indication of the beam weight may be a pointer to an analog beamforming codebook index.

[0029] The indication of the antenna array configuration for the UE may indicate the requested antenna array configuration and a number of reference signals to be used for beam training with respect to the requested antenna array configuration.

[0030] The method of wireless communication may also include sending the certain number of reference signals as a group of consecutive channel state information reference signals (CSI-RS).

[0031] The method of wireless communication may also include: receiving a set of reference signal received power (RSRP) and associated beam indexes from the UE; and selecting a beam from the associated beam index for transmission to the UE.

[0032] The indication of the antenna array configuration for the UE may indicate a currently active antenna array configuration in response to a determination to reject the requested antenna array configuration.

[0033] To achieve the foregoing and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are merely indicative of some of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0035] Figure 2A is a diagram illustrating an example of a first 5G / NR subframe.

[0036] Figure 2B is a diagram illustrating an example of DL channels within a 5G / NR subframe.

[0037] Figure 2C is a diagram illustrating an example of a second 5G / NR subframe.

[0038] Figure 2D is a diagram illustrating an example of UL channels within a 5G / NR subframe.

[0039] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0040] Figure 4 is a schematic diagram of an example antenna array of a UE.

[0041] Figure 5A is a schematic diagram of a first example active antenna configuration including a linear array.

[0042] Figure 5B is a schematic diagram of a second example active antenna configuration including a planar array.

[0043] Fig. 6Ais a schematic diagram of a third example active antenna configuration including a planar array.

[0044] Figure 6B is a schematic diagram of a fourth example active antenna configuration including a linear array.

[0045] Figure 6C is a schematic diagram of a fifth example active antenna configuration including a distributed linear array.

[0046] Figure 7 is a conceptual diagram showing example beams and transmission paths in a radio channel.

[0047] Figure 8 is a message diagram illustrating example signaling for reconfiguring a UE antenna array.

[0048] Fig. 9 is a flow chart of an example method of reconfiguring a UE antenna array for a UE.

[0049] Fig.10 is a flow chart of an example method of reconfiguring a UE antenna array for a base station.

[0050] Fig.11 yes Figure 1 A schematic diagram of example components of a UE.

[0051] Fig.12 yes Figure 1 A schematic diagram of example components of a base station. DETAILED DESCRIPTION

[0052] The specific embodiments described below in conjunction with the accompanying drawings are intended as descriptions of various configurations and are not intended to represent the only configurations in which the concepts described herein can be practiced. The specific embodiments include specific details in order to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, in order to avoid obscuring these concepts, well-known structures and components are shown in block diagram form.

[0053] 5G-NR systems may operate in millimeter wave (mmWave) frequency bands. For example, a communication system may be described based on the frequency band in which the system operates. For example, frequency range 1 (FR1) may refer to frequencies up to 6 GHz, FR2 may refer to frequencies between ~24 GHz and 52.6 GHz, FR3 may refer to frequencies between 6 GHz and ~24 GHz, and FR4 may refer to frequencies above 52.6 GHz.

[0054] Systems at FR4 and above allow more "degrees of freedom" in antenna array arrangement, placement, and dynamic selection (e.g., at the symbol, slot, or slot set level). Typically, in a sub-6GHz / FR1 or FR2 system, all antennas are used, or some fixed a priori subset of antennas is used. For example, a device may include a linear antenna array, and a subset of antennas in the array may be active. Antenna configurations may be used for limited purposes, such as hierarchical beamforming, where beam changes associated with subarray changes are associated with clear mapping between antennas. In contrast, at FR4 (and above), arbitrary subsets of antennas within a larger two-dimensional array may be selectively activated at the symbol or slot or slot set level.

[0055] Degrees of freedom are discussed with respect to two hypothetical systems (a first system at 30 GHz, which is FR2, and a second system at 120 GHz, which may be considered FR4 or possibly exceeding FR4 (e.g., "FR5"). The wavelength (λ) at 120 GHz is 4 times smaller than λ at 30 GHz. Accordingly, the same physical aperture / area may be used at 30 GHz and 120 GHz for antenna array configurations at both frequencies. For example, a system may include simultaneous operation at multiple carriers utilizing flexible / co-located antenna arrays using multiple antenna feeds for different frequency bands. For the same physical aperture at 30 GHz, 4 times more antennas may be packed in each dimension (azimuth or elevation) at 120 GHz. Thus, the aperture of a 4×1 array at 30 GHz may fit into the aperture of a 16×4 antenna array at 120 GHz. Thus, as carrier frequencies increase, medium-sized antenna arrays (e.g., for mobile devices) may become very large arrays.

[0056] Although the cost of antenna arrays is (relatively) low, the antenna arrays are controlled by radio frequency integrated circuits (RFICs), which may include mixers, up / down converters, power amplifiers (PAs), low noise amplifiers (LNAs), phase shifters, automatic gain control (AGCs), etc. RFICs may be relatively expensive components compared to the antennas in the integrated antenna array. For commercial and operational trade-offs (e.g., cost, complexity, power, chip size, etc.), RFICs can only control a certain number of antennas. Typically, the number of antennas controlled by RFICs is between 4-16. But this number may change as technology develops / changes over time. Thus, using larger antenna arrays may require more RFICs. In order to control costs (both manufacturing and operational (e.g., energy) aspects), only a subset of the RFICs required to control the entire array may be included in the device, and only a subset of the included RFICs may be activated.

[0057] In one aspect, the present disclosure provides dynamic switching on these degrees of freedom based on channel / link, power, thermal conditions, and key performance indicator (KPI) targets. Specifically, the present disclosure provides communication between a UE and a base station to select and train a new active antenna configuration, particularly when the new active antenna configuration is significantly different from the previous active antenna configuration. For example, changes to a subset of active antennas may be autonomously performed by the UE (to dynamically control the width of the beam used when beamforming is performed), and adding a new active antenna may involve communication between the UE and the base station. In one implementation, the UE may detect an antenna configuration change condition that triggers a need for an antenna configuration change. The antenna configuration change condition may refer to a condition detected at the UE indicating the possibility of performance improvement when the current antenna configuration is changed. The antenna configuration change condition may be based on predicted performance for a new antenna configuration compared to the current antenna configuration. For example, the antenna configuration change condition may be based on one or more of the following: beam width changes, power or thermal considerations, or support for more RF chains utilizing hybrid beamforming. In response to detecting an antenna configuration change condition, the UE may send a request for beam training to the base station. The request for beam training may include the requested antenna array configuration. The base station may accept or reject the antenna array configuration change request by sending a response including an indication of the antenna array configuration for the UE. If the base station accepts the requested antenna array configuration, the base station and the UE may perform beam training using a certain number of reference signals sent by the base station.

[0058] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. A UE may autonomously request an antenna configuration based on a condition detectable at the UE. Accordingly, the UE is more likely to quickly move to an antenna configuration that meets the UE's performance goals. For example, the UE may autonomously reduce power consumption or temperature as needed. Changes in antenna configuration may also initiate a beam training process. Accordingly, the base station may update the transmit beam and receive beam for the new beam configuration. The updated beam may be selected to provide the best signal quality.

[0059] Several aspects of telecommunication systems will now be presented with reference to various devices and methods. These devices and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (hereinafter collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented in hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0060] As an example, an element, any part of an element, or any combination of multiple elements may be implemented as a "processing system" including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout the present disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as indicating instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable programs, threads in execution, procedures, functions, etc., regardless of whether they are referred to as software, firmware, middleware, microcode, hardware description languages, or other.

[0061] Therefore, in one or more example embodiments, the described functions can be implemented with hardware, software, firmware or any combination thereof. If implemented with software, the functions can be stored on a computer-readable medium or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of computer-readable media of the aforementioned types, or any other medium that can be used to store computer executable code that can be accessed by a computer in the form of instructions or data structures.

[0062] Figure 1 1 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network (e.g., a 5G core (5GC)) 190. The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0063] In one aspect, the UE 104 may include an antenna configuration component 140 for changing an active antenna array configuration of the UE. The antenna configuration component 140 may include a plurality of antennas 141 arranged in an array and selectively activated according to the active antenna array configuration. The antenna configuration component 140 may include a condition component 142 configured to detect an antenna array configuration change condition, a request component 144 configured to send a request for beam training including a requested active antenna configuration, a reconfiguration component 146 configured to configure the plurality of antennas 141 according to a received antenna array configuration change response, and a training component 148 configured to perform beam training for the requested active antenna configuration.

[0064] In another aspect, base station 102 may include antenna control component 198 that works in conjunction with antenna configuration component 140. For example, Fig.12 As shown, the antenna control component 198 may include a request component 1242 configured to receive a request for beam training, an evaluation component 1244 configured to determine whether to grant or deny the request, a configuration component 1246 configured to send an antenna array configuration change response, and a training component 1248 configured to perform beam training for a new active antenna configuration.

[0065] Base stations 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with EPC 160 via backhaul links 132 (eg, S1 interfaces). Backhaul links 132 may be wired or wireless.

[0066] Base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can interface with 5GC 190 via a backhaul link 184. The backhaul link 184 can be wired or wireless. In addition to other functions, the base station 102 can also perform one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., switching, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, allocation for non-access layer (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 can communicate with each other directly or indirectly (e.g., via EPC 160 or 5GC 190) via a backhaul link 134 (e.g., an X2 interface). The backhaul link 134 can be wired or wireless.

[0067] Base station 102 can communicate wirelessly with UE 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, a small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolved Node B (eNB) (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also called a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also called a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link can be through one or more carriers. Base station 102 / UE 104 may use spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in carrier aggregation of up to Yx MHz (x component carriers) for transmission in each direction. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0068] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0069] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 in the 5 GHz unlicensed spectrum via a communication link 154. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether a channel is available before communicating.

[0070] The small cell 102' may operate in a licensed spectrum and / or an unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed spectrum as used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum may improve the coverage of the access network and / or increase the capacity of the access network.

[0071] Base station 102, whether a small cell 102' or a large cell (e.g., a macro base station), can include and / or be referred to as an eNB, a gNodeB (gNB), or another type of base station. Some base stations (e.g., gNB 180) can operate in one or more frequency bands within the electromagnetic spectrum.

[0072] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency ranges denoted FR1 (410 MHz–7.125 GHz) and FR2 (24.25 GHz–52.6 GHz). The frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although portions of FR1 are above 6 GHz, FR1 is typically (interchangeably) referred to as the “Sub-6 GHz” band in various documents and articles. Similar naming issues sometimes arise with respect to FR2, which is typically (interchangeably) referred to as the “millimeter wave” (mmW) band in various documents and articles, but is distinct from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified by the International Telecommunication Union (ITU) as the “millimeter wave” band.

[0073] In view of the above, unless otherwise specifically stated, it should be understood that the term "sub-6GHz" and the like (if used herein) can broadly refer to frequencies that can be less than 6GHz, can be within FR1, or can include intermediate band frequencies. In addition, unless otherwise specifically stated, it should be understood that the term "millimeter wave" and the like (if used herein) can broadly refer to frequencies that can include intermediate band frequencies, can be within FR2, or can be within the EHF band. Communications using mmW radio frequency bands have extremely high path loss and short range. The mmW base station 180 can utilize beamforming 182 with respect to the UE 104 to compensate for the path loss and short range.

[0074] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that controls signaling between the UE 104 and the EPC 160. Typically, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area for broadcasting specific services, and may be responsible for session management (start / stop) and collecting eMBMS-related charging information.

[0075] 5GC 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UDP) 195. AMF 192 may communicate with unified data management (UDM) 196. AMF 192 is a control node that handles signaling between UE 104 and 5GC 190. Typically, AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 is connected to IP services 197. IP services 197 may include the Internet, intranet, IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0076] A base station may include and / or be referred to as a gNB, a Node B, an evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other suitable term. Base station 102 provides an access point to EPC 160 or 5GC 190 for UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functional device. Some UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0077] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0078] Figure 2A FIG200 is a diagram illustrating an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG230 is a diagram illustrating an example of DL channels within a 5G / NR subframe. Figure 2C FIG250 is a diagram illustrating an example of a second subframe within a 5G / NR frame structure. Figure 2D FIG280 is a diagram illustrating an example of UL channels within a 5G / NR subframe. The 5G NR frame structure may be of FDD type, where for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to either DL or UL; or the 5G / NR frame structure may be of TDD type, where for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to both DL and UL. Figure 2A , 2CIn the example provided, the 5G / NR frame structure is assumed to be of TDD type, where subframe 4 is configured with slot format 28 (primarily DL), where D is DL, U is UL, X is flexible for use between DL / UL, and subframe 3 is configured with slot format 34 (primarily UL). Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mix of DL symbols, UL symbols, and flexible symbols. The UE is configured with a slot format by a received slot format indicator (SFI) (dynamically through DL control information (DCI) or semi-statically / statically through radio resource control (RRC) signaling). Note that the following description also applies to a TDD type 5G NR frame structure.

[0079] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 subframes (1ms) of equal size. Each subframe may include one or more time slots. A subframe may also include a mini-time slot, which may include 7, 4, or 2 symbols. Depending on the time slot configuration, each time slot may include 7 or 14 symbols. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbol on the DL may be a cyclic prefix (CP) OFDM (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput scenarios) or a discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited situations; limited to single-stream transmission). The number of time slots within a subframe is based on the time slot configuration and numerology. For slot configuration 0, different digital schemes μ = 0 to 5 allow 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Therefore, for slot configuration 0 and digital scheme μ, there are 14 symbols per slot and 2 per subframe. μ time slots. The subcarrier spacing and symbol length / duration are functions of the digital scheme. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is the digital scheme 0 to 5. Thus, digital scheme μ=0 has a subcarrier spacing of 15kHz and digital scheme μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely proportional to the subcarrier spacing. Figures 2A-2DAn example of slot configuration 0 is provided, where each slot has 14 symbols and the digital scheme μ = 0, each subframe has 1 slot. The subcarrier spacing is 15 kHz and the symbol duration is approximately 66.7 μs.

[0080] A resource grid may be used to represent a frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0081] like Figure 2A As shown in FIG. 1 , some REs carry reference (pilot) signals (RS) for UEs. RSs may include demodulation RSs (DM-RSs) (although indicated as Rs for a particular configuration). x , where 100x is the port number, but other DM-RS configurations are also possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0082] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI in one or more control channel elements (CCEs), each CCE includes nine RE groups (REGs), and each REG includes four consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) can be within symbol 2 of a specific subframe of the frame. The UE 104 uses the PSS to determine the subframe timing / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) can be within symbol 4 of a specific subframe of the frame. The UE uses the SSS to determine the physical layer cell identification group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identification group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the above-mentioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not sent through the PBCH (such as System Information Blocks (SIBs)), and paging messages.

[0083] like Figure 2CAs shown in , some REs carry DM-RS for channel estimation at the base station (although indicated as R for one specific configuration, other DM-RS configurations are also possible). The UE can send DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be sent in the first one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used, the PUCCH DM-RS can be sent in different configurations. Although not shown, the UE can send a sounding reference signal (SRS). The SRS can be used by the base station for channel quality estimation to achieve frequency-dependent scheduling on the UL.

[0084] Figure 2D An example of various UL channels within a subframe of a frame is illustrated. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0085] Figure 33 is a block diagram of a base station 310 communicating with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements the functions of layer 3 and layer 2. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel prioritization.

[0086] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing (e.g., according to the active antenna array configuration). The TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from channel estimator 374 can be used to determine coding and modulation schemes, as well as for spatial processing. Channel estimates can be derived based on reference signals and / or channel condition feedback sent by UE 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier with a corresponding spatial stream for transmission.

[0087] At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation point sent by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359 which implements layer 3 and layer 2 functions.

[0088] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0089] Similar to the functions described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel prioritization.

[0090] Channel estimates derived by the channel estimator 358 based on a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0091] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0092] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0093] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to the UE 104. Figure 1 At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to the antenna configuration component 140 at the base station 102. Figure 1 Various aspects related to the antenna control component 198.

[0094] Go to Figure 4 , schematic diagram 400 of an example antenna array 410 includes multiple antennas 420 and multiple RFICs 430 (e.g., RFICs 430a, 430b, 430c, 430d). Antenna array 410 can be located in UE 104 (e.g., as antenna 141). Antenna array 410 can include up to four RFICs 430 for controlling multiple antenna modules or panels via RF switches. In the example shown, each RFIC 430 can control up to 16 antennas. Putting more RFICs into the UE may increase production costs. A universal RFIC group that utilizes dynamic switching between antenna modules / panels and sub-arrays can allow flexibility for RFICs to control multiple antennas. Complex feeder crossing is a compromise for flexibility. In an alternative example, if each RFIC can control 8 antennas per RFIC, a 16×4 array at 120GHz can use 8 RFICs (64 antennas / 8 antennas per RFIC).

[0095] As discussed in further detail below, to reduce power consumption, antenna configuration component 140 can configure a subset of antennas 420 as active antennas. In some scenarios, antenna configuration component 140 can limit the number of active RFICs 430 to save power.

[0096] Go to Figure 5A , schematic diagram 500 includes a first example active antenna configuration 510 for an example antenna array 410. The active antenna configuration 510 includes a 4×1 linear array of antennas 420 that are each controlled by RFIC 430b. Figure 5B4, schematic 502 includes a second example active antenna configuration 520. The second example active antenna configuration 520 includes a 2x2 planar array of antennas 420 that are each controlled by RFIC 430b.

[0097] In one aspect, antenna configuration component 140 can switch between a 4×1 linear array of active antenna configuration 510 and a 2×2 planar array of active antenna configuration 520 without sacrificing equivalent isotropic radiated power (EIRP). For example, at the same EIRP, a 4×1 linear array of active antenna configuration 510 can produce a relatively wider elevation spread and a relatively narrower azimuth spread than a 2×2 planar array of active antenna configuration 520, which can produce a relatively wider azimuth spread and a relatively narrower elevation spread. Accordingly, antenna configuration component 140 can trade off appropriate angular spread in azimuth and elevation by changing the active antenna configuration.

[0098] Steering attachment Fig. 6A , 6B 6C, three example antenna configurations 610, 620, and 630 are shown, each controlled by two RFICs 430. In the first example active antenna configuration 610, RFIC 430b can control a 4×2 planar array. In the second example active antenna configuration 620, RFIC 430b and RFIC 430c can control an 8×1 linear array. In the third example antenna configuration 630, RFIC 430a and RFIC 430c can control a 4×2 distributed array with two 4×1 arrays each.

[0099] In one aspect, the antenna configuration component 140 can switch between active antenna configurations 610, 620, and 630. Because the 4×2 array of active antenna configuration 610 is controlled by a single RFIC 430b, the array can consume less power. The 4×2 array of active antenna configuration 610 can still have a wider beamwidth than active antenna configuration 510. Accordingly, active antenna configuration 610 can be suitable for situations when the angular spread of the main cluster is wider. The 8×1 array of active antenna configuration 620 can consume more power than active antenna configuration 610 because the array is controlled by two RFICs 430b and 430c. Active antenna configuration 620 can have a narrower beamwidth in azimuth and a wider beamwidth in elevation. Accordingly, active antenna configuration 620 can be suitable for situations when the angular spread of the main cluster matches the generated beam shape / directivity pattern. Since the active antenna configuration 630 is controlled by two RFICs 430a and 430c, the 4×2 distributed array of the active antenna configuration 630 may consume more power than the active antenna configuration 610. The active antenna configuration 630 may be useful for hybrid beamforming because the antennas are widely spaced and therefore uncorrelated, which allows independent data streams to be used on each 4×1 array.

[0100] In one aspect, dynamically changing the active beam configuration when there are more degrees of freedom in the possible configurations may have a greater impact on the base station than dynamically changing the linear array. For example, the UE may change the active antenna configuration among a subset of antennas in a linear array without changing the base station beam. For example, when the UE changes from a 4×1 array to a 2×1 array and then to a 1×1 array, the beam width may become wider and wider. The 1×1 array is a subset of the 2×1 array, and the 2×1 array is a subset of the 4×1 array. In contrast, with additional degrees of freedom (e.g., as in the example active antenna configuration described above), the antennas of the second array may have no relationship with the antennas of the first array. Therefore, the beam widths of different active antenna configurations may be unrelated. The base station may need to change its beam in response to a UE antenna array configuration or beam change. In one aspect, the base station may control the UE antenna array configuration or beam change, at least when the change results in the activation or deactivation of antennas that are not related to the previous configuration or the new configuration.

[0101] Go to Figure 7, conceptual diagram 700 includes beam 710 sent from base station 102 to UE 104. Beam 710 can be the result of different antenna configurations at base station 102, which can typically include a larger antenna array for beam steering. For example, beam 710 can include a relatively narrow first beam 710a and a relatively wide second beam 710b. Base station 102 can control beam weights to steer beam 710 in a particular direction. For example, a channel can include multiple paths 720 (e.g., paths 720a-720e) between base station 102 and UE 104. For example, if there is a line of sight between base station 102 and UE 104, a direct path 720c can exist. RF signals can also follow indirect paths. For example, signals can be reflected from objects such as buildings, vehicles, or windows. From the perspective of UE 104, the signal can appear to come from cluster 730. Clusters (e.g., clusters 730b-730d) can be reflection or diffraction sources of signals reaching UE 104. For example, cluster 730c may correspond to base station 102, and clusters 730b and 730d may correspond to objects that reflect signals in indirect paths 720b and 720d, respectively. Other paths such as paths 720a and 720e may not reach UE 104 with sufficient signal strength. UE 104 may have an active antenna configuration that generates receive beams 740 (e.g., receive beams 740a and 740b). For example, receive beam 740a may be generated by a first active antenna configuration, and receive beam 740b may be generated by a second active antenna configuration. UE 104 may control antenna weights to steer receive beam 740 toward one or more clusters 730. The strongest cluster may be referred to as a primary cluster, while other clusters may be referred to as secondary primary clusters.

[0102] UE 104 can dynamically change the active antenna configuration to align one or more clusters. For example, UE 104 can use the active antenna configuration for generating receive beam 740a when cluster 730b is the main cluster. UE 104 can change the active antenna configuration to generate receive beam 740b when there are multiple strong clusters. In the case of a linear antenna array, changing between antenna subsets can affect the beam width of receive beam 740, but may not have a significant impact on the direction of other dimensions of receive beam 740. When UE 104 has a larger antenna array with more degrees of freedom, changes in the active antenna configuration can change receive beam 740 in different dimensions. For example, the beam can expand or shrink in azimuth dimension or elevation dimension. Accordingly, as the degrees of freedom in the active antenna configuration selection increase, the greater the possibility that the optimal beam of base station 102 will also change.

[0103] Figure 88 is a message diagram 800 illustrating an example process and messages for dynamically changing an active antenna configuration of a UE 104. Initially, the UE 104 may communicate a message 810 with the base station 102 according to a first antenna configuration. For example, the first antenna configuration may be a default antenna configuration, the base station 102 may configure the UE 104 with the first antenna configuration (e.g., using RRC signaling), or the first antenna configuration may be dynamically selected by the UE 104.

[0104] At processing block 820, UE 104 may detect an antenna configuration change condition. The antenna configuration change condition may be based on one or more of: beam width change, power or thermal considerations, or support for more RF chains utilizing hybrid beamforming. For example, as described above with respect to Figure 7 Discussed, the UE 104 and / or the antenna configuration component 140 may determine (e.g., based on a reference signal) that a different active antenna configuration will produce a receive beam 740 that will provide better performance (e.g., greater signal strength). For example, the new active antenna configuration may capture the angular spread of the primary cluster and / or the secondary primary cluster in the RF channel. As another example, the UE 104 and / or the antenna configuration component 140 may determine that the power consumption of the current active antenna configuration is too large (e.g., based on measured power consumption or battery charging), or that the temperature of the UE 104 or its components is too high (e.g., based on a thermal sensor). On the other hand, the UE 104 and / or the antenna configuration component 140 may determine that, for example, if a higher data rate is required, support for additional RF chains may be required. The UE 104 and / or the antenna configuration component 140 may determine that an active antenna configuration such as the example active antenna configuration 630 may support additional RF chains in order to receive additional streams. The above-mentioned antenna change conditions may be based on measurements performed at the UE or an internal state of the UE, which may not be reported to the base station. Accordingly, by detecting antenna change conditions and initiating antenna array configuration changes and beam training, the UE can improve performance goals of the UE that may not be detected by the network.

[0105] In response to detecting an antenna configuration change condition in processing block 820, UE 104 may send a request message 830 requesting beam training for antenna array configuration. Beam training may refer to a process in which UE 104 and base station 102 communicate using different beams in order to select a beam for future communication. For example, base station 102 may send reference signals using different beams, and UE may feedback the selected beam and / or measurements of different beams. Request message 830 may indicate a requested antenna array configuration (e.g., one of active antenna configurations 510, 520, 610, 620, 630). For example, the requested antenna array configuration may be based on a detected antenna array change condition. In some implementations, request message 830 may be referred to as an antenna array configuration change request message. In one aspect, the antenna array configuration may include an indication of beam weights used with the requested antenna array configuration. For example, UE 104 may select beam weights based on measurements of reference signals received during communication using the current antenna array configuration. For example, the beam weights may be based on a prediction of the best beam to use with the requested antenna array configuration. The beam weights may be indicated as codebook entries, for example, from a codebook defined in a standard, rule, or configuration sent via signaling. The request message 830 may be sent, for example, as an RRC configuration message or a MAC CE.

[0106] The base station 102 may determine whether to grant or reject the request message 830. For example, if the base station 102 cannot support the requested antenna array configuration given the current allocation of resources (e.g., transmit antennas), the base station 102 may reject the requested antenna array configuration. The base station 102 may send a response message 840 indicating the antenna array configuration for use by the UE. When the base station 102 rejects the requested antenna array configuration, the response message 840 may indicate the current antenna array configuration of the UE. When the base station 102 accepts the requested antenna array configuration, the response message 840 may indicate a certain number of reference signals to be used for beam training regarding the requested antenna array configuration. For example, when different reference signals 860 are to be sent, the response message 840 may indicate time domain and frequency domain resources. The response message 840 may be sent, for example, as an RRC configuration message, a MAC CE, or a DCI.

[0107] At processing block 850, UE 104 may perform beam training for the requested antenna array configuration. That is, UE 104 may change to the requested antenna array configuration as the new active antenna configuration. UE 104 may measure each of reference signals 860 using the new active antenna configuration to determine the best beam. For example, the best beam may be the beam that has the best reference signal received power (RSRP) for transmitting one of reference signals 860. UE 104 may send a beam training message 870 including a beam index of the best beam and the RSRP of the best beam. Accordingly, base station 102 may select the best beam for communication with UE 104.

[0108] Fig. 9 is a flow chart of a method 900 of wireless communication. The method 900 may be performed by a UE (e.g., UE 104, which may include memory 360 and may be the entire UE 104 or a component of UE 104, such as antenna configuration component 140, TX processor 368, RX processor 356, and / or controller / processor 359). In one aspect, the method 900 may be performed while communicating with a base station (e.g., base station 102, which may include memory 376 and may be the entire base station 102 or a component of base station 102, such as antenna control component 198, TX processor 316, RX processor 370, and / or controller / processor 375). Optional blocks are illustrated with dashed lines.

[0109] At block 910, method 900 may include detecting an antenna array change condition at the UE. In one aspect, for example, the UE 104, the RX processor 356, and / or the controller / processor 359 may execute the antenna configuration component 140 and / or the condition component 142 to detect an antenna array change condition at the UE 104. For example, the antenna array change condition may be based on the angular spread of the primary cluster and the secondary primary cluster in the channel between the base station and the UE. For example, the UE 104 may determine that different active antenna array configurations may generate beams including one or more additional clusters. As another example, the antenna array change condition may be based on power considerations of the UE (e.g., a low battery condition). As another example, the antenna array change condition may be based on thermal considerations of the UE (e.g., a temperature exceeding a threshold). As another example, the antenna array change condition may be based on support for additional radio frequency chains utilizing a hybrid beamforming architecture. Therefore, the UE 104, the RX processor 356, and / or the controller / processor 359 (executing the antenna configuration component 140 and / or the condition component 142) may provide a unit for detecting an antenna array change condition at the UE.

[0110] At block 920, method 900 may include sending a request for beam training for antenna array configuration from the UE in response to detecting. In one aspect, for example, the UE 104, the TX processor 368, and / or the controller / processor 359 may execute the antenna configuration component 140 and / or the request component 144 to send a request for beam training for antenna array configuration from the UE in response to detecting (e.g., request message 830). The request for beam training may include the requested antenna array configuration. The request for beam training may include an indication of beam weights to be used with the requested antenna array configuration. For example, the indication of beam weights may be a pointer to an analog beamforming codebook index. Accordingly, the UE 104, the TX processor 368, and / or the controller / processor 359 (executing the antenna configuration component 140 and / or the request component 144) may provide a unit for sending a request for beam training for antenna array configuration from the UE in response to detecting.

[0111] At block 930, method 900 may include receiving an indication of an antenna array configuration for the UE from a base station. In one aspect, for example, the UE 104, the RX processor 356, and / or the controller / processor 359 may execute the antenna configuration component 140 and / or the reconfiguration component 146 to receive an indication of an antenna array configuration for the UE 104 from the base station 102 (e.g., an antenna array configuration change response message 840). When the base station accepts the request, the indication of the antenna array configuration for the UE may indicate the requested antenna array configuration and a certain number of reference signals to be used for beam training with respect to the requested antenna array configuration. When the base station rejects the request, the indication of the antenna array configuration may indicate the active antenna array configuration. Accordingly, the UE 104, the RX processor 356, and / or the controller / processor 359 (executing the antenna configuration component 140 and / or the reconfiguration component 146) may provide a unit for receiving an indication of an antenna array configuration for the UE from the base station.

[0112] At block 940, method 900 may optionally include configuring the antenna array of the UE based on the requested antenna array configuration to activate the reconfigured active antenna array configuration. In one aspect, for example, the UE 104, the RX processor 356, and / or the controller / processor 359 may execute the antenna configuration component 140 and / or the reconfiguration component 146 to configure the antenna array 410 of the UE 104 based on the requested antenna array configuration to activate the reconfigured active antenna array configuration. For example, the reconfiguration component 146 may control one or more of the RFICs 430 to energize the antennas 420 in the active array of the requested antenna array configuration. For example, if the active antenna array configuration 510 is selected, the RFIC 430b may energize the antennas in the linear array. As another example, if the active antenna configuration 630 is selected, the RFICs 430a and 430c may energize the antennas in the distributed planar array. Accordingly, the UE 104, the RX processor 356 and / or the controller / processor 359 (executing the antenna configuration component 140 and / or the reconfiguration component 146) may provide a unit for configuring the antenna array of the UE based on the requested antenna array configuration to activate the reconfigured active antenna array configuration.

[0113] At block 950, method 900 may optionally include training the reconfigured active antenna array configuration based on a number of reference signals. In one aspect, for example, UE 104, RX processor 356, and / or controller / processor 359 may execute antenna configuration component 140 and / or training component 148 to train the reconfigured active antenna array configuration based on a number of reference signals. Accordingly, UE 104, RX processor 356, and / or controller / processor 359 (executing antenna configuration component 140 and / or training component 148) may provide means for training the reconfigured active antenna array configuration based on a number of reference signals.

[0114] At block 960, method 900 may optionally include sending a set of reference signal received power (RSRP) and associated beam indexes to the base station. In one aspect, for example, UE 104, TX processor 368, and / or controller / processor 359 may execute antenna configuration component 140 and / or training component 148 to send reference signal received power (RSRP) and associated beam indexes to the base station. Accordingly, UE 104, TX processor 368, and / or controller / processor 359 (executing antenna configuration component 140 and / or training component 148) may provide a unit for sending reference signal received power (RSRP) and associated beam indexes to the base station. Base station 102 may utilize RSRP and associated beam indexes to select a beam for transmission. UE 104 may then receive transmissions from base station 102 using the reconfigured active antenna array configuration.

[0115] Fig.10 1 is a flow chart of a method 1000 of wireless communication. The method 1000 may be performed by a base station (e.g., base station 102, which may include memory 376 and may be the entire base station 102 or a component of base station 102, such as antenna control component 198, TX processor 316, RX processor 370, and / or controller / processor 375). In one aspect, the method 1000 may be performed in communication with a UE (e.g., UE 104, which may include memory 360 and may be the entire UE 104 or a component of UE 104, such as antenna configuration component 140, TX processor 368, RX processor 356, and / or controller / processor 359). Optional blocks are illustrated with dashed lines.

[0116] At block 1010, method 1000 may include receiving, at a base station, from a UE a request to change an active antenna array configuration of the UE to a requested antenna array configuration. In one aspect, for example, the base station 102, the RX processor 370, and / or the controller / processor 375 may execute the antenna control component 198 and / or the request component 1242 to receive, at the base station 102, from the UE 104 a request for beam training for the requested antenna array configuration. For example, the request for beam training may indicate support for additional radio frequency chains utilizing a hybrid beamforming architecture. As another example, the request for beam training may include an indication of beam weights to be used with the requested antenna array configuration. The indication of beam weights may be a pointer to an analog beamforming codebook index. Accordingly, the base station 102, the RX processor 370, and / or the controller / processor 375 (executing the antenna control component 198 and / or the request component 1242) may provide a unit for receiving, at the base station, a request for beam training for the requested antenna array configuration from the UE.

[0117] At block 1020, method 1000 may include determining whether to grant or deny the requested antenna array configuration of the UE. In one aspect, for example, the base station 102 and / or the controller / processor 375 may execute the antenna control component 198 and / or the evaluation component 1244 to determine whether to grant or deny the requested antenna array configuration of the UE. For example, if the base station 102 cannot support the requested antenna array configuration given the current allocation of resources (e.g., transmit antennas), the evaluation component 1244 may deny the requested antenna array configuration. For example, the requested active antenna array configuration may require additional antennas at the base station in order to steer the beam. If the required antenna is being used for another UE or another frequency band, the evaluation component 1244 may deny the request. Accordingly, the base station 102 and / or the controller / processor 375 (executing the antenna control component 198 and / or the evaluation component 1244) may provide a unit for determining whether to grant or deny the requested antenna array configuration of the UE.

[0118] At block 1030, method 1000 may include sending, from the base station, an indication of an antenna array configuration for the UE. In one aspect, for example, base station 102, TX processor 316, and / or controller / processor 375 may execute antenna control component 198 and / or configuration component 1246 to send, from base station 102, an indication of an antenna array configuration for the UE. Accordingly, base station 102, TX processor 316, and / or controller / processor 375 executing antenna control component 198 and / or configuration component 1246 may provide means for sending, from the base station, an indication of an antenna array configuration for the UE.

[0119] At block 1040, method 1000 may optionally include transmitting a certain number of reference signals as a set of consecutive CSI-RS. In one aspect, for example, base station 102, TX processor 316, and / or controller / processor 375 may execute antenna control component 198 and / or training component 1248 to transmit a certain number of reference signals as a set of consecutive CSI-RS. Accordingly, base station 102, TX processor 316, and / or controller / processor 375 executing antenna control component 198 and / or training component 1248 may provide means for transmitting a certain number of reference signals as a set of consecutive CSI-RS.

[0120] At block 1050, method 1000 may optionally include receiving a set of RSRPs and associated beam indices from the UE. In one aspect, for example, base station 102, RX processor 370, and / or controller / processor 375 may execute antenna control component 198 and / or training component 1248 to receive the set of RSRPs and associated beam indices from the UE. Accordingly, base station 102, RX processor 370, and / or controller / processor 375 executing antenna control component 198 and / or training component 1248 may provide a means for receiving a set of RSRPs and associated beam indices from the UE.

[0121] At block 1060, the method 1000 may optionally include selecting a beam from the associated beam index for transmission to the UE. In one aspect, for example, the base station 102, the TX processor 316, and / or the controller / processor 375 may execute the antenna control component 198 and / or the training component 1248 to select a beam from the associated beam index for transmission to the UE. That is, the training component 1248 may determine the antenna weights for sending a reference signal corresponding to the selected beam index and use these antenna weights for future transmissions to the UE. The training component 1248 may also select a transmit power based on RSRP. Accordingly, the base station 102, the RX processor 370, and / or the controller / processor 375 executing the antenna control component 198 and / or the training component 1248 may provide a unit for selecting a beam from the associated beam index for transmission to the UE. The base station 102 may use the antenna array configuration for the UE and the information from the beam training to communicate with the UE.

[0122] Reference Fig.11 , an example of an implementation of the UE 104 may include various components, some of which have been described above, but include components such as one or more processors 1112 and memory 1116 communicating via one or more buses 1144 and a transceiver 1102, which may work in conjunction with a modem 1114 and / or antenna configuration component 140 to implement one or more functions described herein related to configuring an active antenna array at the UE. In addition, the one or more processors 1112, modem 1114, memory 1116, transceiver 1102, RF front end 1188, and one or more antennas 1165 may be configured to (simultaneously or non-simultaneously) support voice and / or data calls utilizing one or more radio access technologies. Antenna 1165 may include one or more antennas, antenna elements, and / or antenna arrays.

[0123] In one aspect, the one or more processors 1112 may include a modem 1114, which may use one or more modem processors. Various functions associated with the antenna configuration component 140 may be included in the modem 1114 and / or the processor 1112, and in one aspect may be performed by a single processor, while in other aspects, different functions may be performed by a combination of two or more different processors. For example, in one aspect, the one or more processors 1112 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with the transceiver 1102. In other aspects, some features of the one or more processors 1112 and / or the modem 1114 associated with the antenna configuration component 140 may be performed by the transceiver 1102.

[0124] In addition, the memory 1116 can be configured to store data used herein, and / or a local version of the application 1175, or the configuration component 140 and / or one or more subcomponents thereof executed by the at least one processor 1112. The memory 1116 may include any type of computer-readable medium usable by a computer or at least one processor 1112, such as random access memory (RAM), read-only memory (ROM), tape, disk, optical disk, volatile memory, non-volatile memory, and any combination of these. In one aspect, for example, the memory 1116 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the antenna configuration component 140 and / or one or more subcomponents thereof, and / or data associated therewith, when the UE 104 is operating the at least one processor 1112 to execute the antenna configuration component 140 and / or one or more subcomponents thereof.

[0125] The transceiver 1102 may include at least one receiver 1106 and at least one transmitter 1108. The receiver 1106 may include hardware, firmware, and / or software code executable by a processor for receiving data, the code including instructions and stored in a memory (e.g., a computer-readable medium). The receiver 1106 may be, for example, a radio frequency (RF) receiver. In one aspect, the receiver 1106 may receive a signal transmitted by at least one base station 102. In addition, the receiver 1106 may process the signal received in this manner, and may also obtain measurement results of the signal, such as, but not limited to, Ec / Io, SNR, RSRP, RSSI, etc. The transmitter 1108 may include hardware, firmware, and / or software code executable by a processor for sending data, the code including instructions and stored in a memory (e.g., a computer-readable medium). Suitable examples of the transmitter 1108 may include, but are not limited to, an RF transmitter.

[0126] In addition, in one aspect, the UE 104 may include an RF front end 1188 that may operate in communication with one or more antennas 1165 and the transceiver 1102 for receiving and transmitting radio transmissions, such as wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by the UE 104. The RF front end 1188 may be connected to the one or more antennas 1165 and may include one or more low noise amplifiers (LNAs) 1190, one or more switches 1192, one or more power amplifiers (PAs) 1198, and one or more filters 1196 for transmitting and receiving RF signals.

[0127] In one aspect, the LNAs 1190 can amplify received signals at a desired output level. In one aspect, each LNA 1190 can have specified minimum and maximum gain values. In one aspect, based on the desired gain value for a particular application, the RF front end 1188 can use one or more switches 1192 to select a particular LNA 1190 and its specified gain value.

[0128] In addition, for example, the RF front end 1188 can use one or more PAs 1198 to amplify the signal for RF output at a desired output power level. In one aspect, each PA 1198 can have a specified minimum and maximum gain value. In one aspect, based on the desired gain value for a particular application, the RF front end 1188 can use one or more switches 1192 to select a particular PA 1198 and its specified gain value.

[0129] In addition, for example, the RF front end 1188 can use one or more filters 1196 to filter the received signal to obtain an input RF signal. Similarly, in one aspect, for example, a corresponding filter 1196 can be used to filter the output from the corresponding PA 1198 to produce an output signal for transmission. In one aspect, each filter 1196 can be connected to a specific LNA 1190 and / or PA 1198. In one aspect, based on the configuration as specified by the transceiver 1102 and / or the processor 1112, the RF front end 1188 can use one or more switches 1192 to select a transmit path or a receive path using a specified filter 1196, LNA 1190, and / or PA 1198.

[0130] As such, the transceiver 1102 may be configured to transmit and receive wireless signals via the RF front end 1188 through one or more antennas 1165. In one aspect, the transceiver may be tuned to operate at a specified frequency so that the UE 104 may communicate, for example, with one or more base stations 102 or one or more cells associated with one or more base stations 102. In one aspect, for example, the modem 1114 may configure the transceiver 1102 to operate at a specified frequency and power level based on a UE configuration of the UE 104 and a communication protocol used by the modem 1114.

[0131] In one aspect, modem 1114 can be a multi-band multi-mode modem that can process digital data and communicate with transceiver 1102 so that digital data is transmitted and received using transceiver 1102. In one aspect, modem 1114 can be multi-band and configured to support multiple frequency bands for a specific communication protocol. In one aspect, modem 1114 can be multi-mode and configured to support multiple working networks and communication protocols. In one aspect, based on a specified modem configuration, modem 1114 can control one or more components (e.g., RF front end 1188, transceiver 1102) of UE 104 to enable sending and / or receiving signals from the network. In one aspect, modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, modem configuration can be based on UE configuration information associated with UE 104 as provided by the network during cell selection and / or cell reselection.

[0132] Reference Fig.12 , an example of an implementation of the base station 102 may include various components, some of which have been described above, but include components such as one or more processors 1212 and memory 1216 that communicate via one or more buses 1254 and a transceiver 1202, which may work with a modem 1214 and an antenna control component 198 to implement one or more functions related to UE antenna configuration control described herein.

[0133] Although the transceiver 1202, receiver 1206, transmitter 1208, one or more processors 1212, memory 1216, application 1275, bus 1254, RF front end 1288, LNA 1290, switch 1292, filter 1296, PA 1298 and one or more antennas 1275 may be the same as or similar to the corresponding components of UE 104 as described above, they are configured or otherwise programmed for base station operations as opposed to UE operations.

[0134] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is an illustration of an exemplary manner. Based on design preferences, it should be understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged. In addition, some blocks can be combined or omitted. The attached method claims present the elements of each block in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0135] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but to conform to the full scope consistent with the language claims, wherein the reference element in the singular form is not intended to represent "one and only one" (unless specifically stated), but "one or more". The word "exemplary" is used herein to represent "used as an example, instance or illustration". Any aspect described herein as "exemplary" is not necessarily interpreted as being preferred to or conducive to other aspects. Unless otherwise specified, the term "some" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C", and "A, B, C or any combination thereof" include any combination of A, B and / or C, and may include multiple A, multiple B or multiple C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure are known or subsequently will become known to those of ordinary skill in the art, are expressly incorporated herein by reference, and are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, regardless of whether the disclosure is expressly stated in the claims. The words "module," "mechanism," "element," "device," and the like may not replace the word "unit." Therefore, no claim element is to be interpreted as a functional module unless the element is explicitly described using the phrase "unit for..."

Claims

1. A method of wireless communication, comprising: detecting an antenna array change condition at a user equipment (UE); sending, from the UE, a request to change an active antenna array configuration of the UE to a requested antenna array configuration; receiving, from a base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A reconfigured active antenna array with the new antenna array configuration is trained based on the reference signal.

2. The method according to claim 1, wherein: The request to change the active antenna array configuration of the UE to the requested antenna array configuration includes an indication of beam weights to be used with the requested antenna array configuration.

3. The method according to claim 2, wherein: The indication of a beam weight is based on a prediction of an optimal beam for use with the requested antenna array configuration.

4. The method according to claim 2, wherein: The indication of the beam weight is a pointer to an analog beamforming codebook index.

5. The method according to claim 1, wherein: The antenna array change condition is based on angular spreads of a primary cluster and a secondary primary cluster in a channel between the base station and the UE.

6. The method according to claim 1, wherein: The antenna array change condition is based on power considerations or thermal considerations of the UE.

7. The method according to claim 1, wherein: The antenna array change condition is based on support for additional radio frequency chains utilizing a hybrid beamforming architecture.

8. The method according to claim 1, wherein: The indication of resources for reference signals to be used for beam training includes a set of consecutive channel state information reference signals (CSI-RS).

9. The method according to claim 1, wherein: Training the reconfigured active antenna array having the new antenna array configuration based on the reference signal comprises: measuring each of the reference signals using the new active antenna configuration to determine an optimal beam; and A beam training message including a beam index of the best beam is sent.

10. The method according to claim 9, wherein: The best beam corresponds to a reference signal having a measured best reference signal received power (RSRP), and the beam training message includes the RSRP of the best beam.

11. A method of wireless communication, comprising: receiving, at a base station, from a user equipment (UE), a request for beam training for a requested antenna array configuration; determining whether to grant or deny the requested antenna array configuration; sending, from the base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A set of reference signals is sent from the base station on the resources.

12. The method according to claim 11, wherein: The request for beam training for a requested antenna array configuration includes an indication of beam weights to be used with the requested antenna array configuration.

13. The method according to claim 12, wherein: The indication of a beam weight is based on a prediction of an optimal beam for use with the requested antenna array configuration.

14. The method according to claim 12, wherein: The indication of the beam weight is a pointer to an analog beamforming codebook index.

15. The method according to claim 12, wherein: The set of reference signals is based on the indication of beam weights for use with the requested antenna array configuration.

16. The method according to claim 11, wherein: The set of reference signals includes a set of consecutive channel state information reference signals (CSI-RS).

17. The method according to claim 11, further comprising: A beam training message is received indicating a beam index of a best beam.

18. The method according to claim 17, wherein: The best beam corresponds to a reference signal having a measured best reference signal received power (RSRP), and the beam training message includes the RSRP of the best beam.

19. An apparatus for wireless communication, comprising: Memory; as well as One or more processors, coupled to the memory and configured, individually or in combination, to: detecting an antenna array change condition at a user equipment (UE); sending, from the UE, a request to change an active antenna array configuration of the UE to a requested antenna array configuration; receiving, from a base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A reconfigured active antenna array with the new antenna array configuration is trained based on the reference signal.

20. The device according to claim 19, wherein The request to change the active antenna array configuration of the UE to the requested antenna array configuration includes an indication of beam weights to be used with the requested antenna array configuration.

21. The device according to claim 20, wherein: The indication of a beam weight is based on a prediction of an optimal beam for use with the requested antenna array configuration.

22. The device according to claim 20, wherein: The indication of the beam weight is a pointer to an analog beamforming codebook index.

23. The device according to claim 19, wherein: The antenna array change condition is based on angular spreads of a primary cluster and a secondary primary cluster in a channel between the base station and the UE.

24. The device according to claim 19, wherein The antenna array change condition is based on power considerations or thermal considerations of the UE.

25. The device according to claim 19, wherein The antenna array change condition is based on support for additional radio frequency chains utilizing a hybrid beamforming architecture.

26. The device according to claim 19, wherein The indication of resources for reference signals to be used for beam training includes a set of consecutive channel state information reference signals (CSI-RS).

27. The device according to claim 19, wherein Training the reconfigured active antenna array having the new antenna array configuration based on the reference signal comprises: measuring each of the reference signals using the new active antenna configuration to determine an optimal beam; and A beam training message including a beam index of the best beam is sent.

28. The device according to claim 27, wherein The best beam corresponds to a reference signal having a measured best reference signal received power (RSRP), and the beam training message includes the RSRP of the best beam.

29. An apparatus for wireless communication, comprising: Memory; as well as One or more processors coupled to the memory and configured to: receiving, at a base station, from a user equipment (UE), a request for beam training for a requested antenna array configuration; determining whether to grant or deny the requested antenna array configuration; sending, from the base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A set of reference signals is sent from the base station on the resources.

30. The device according to claim 29, wherein: The request for beam training for a requested antenna array configuration includes an indication of beam weights to be used with the requested antenna array configuration.

31. The device according to claim 30, wherein The indication of a beam weight is based on a prediction of an optimal beam for use with the requested antenna array configuration.

32. The device according to claim 30, wherein: The indication of the beam weight is a pointer to an analog beamforming codebook index.

33. The device according to claim 30, wherein: The set of reference signals is based on the indication of beam weights for use with the requested antenna array configuration.

34. The apparatus of claim 29, wherein: The set of reference signals includes a set of consecutive channel state information reference signals (CSI-RS).

35. The apparatus of claim 29, further comprising: A beam training message including a beam index of a best beam is received.

36. The device according to claim 35, wherein The best beam corresponds to a reference signal having a measured best reference signal received power (RSRP), and the beam training message includes the RSRP of the best beam.

37. A non-transitory computer readable medium storing computer executable code, which, when executed by a processor, causes the processor to: detecting an antenna array change condition at a user equipment (UE); sending, from the UE, a request to change an active antenna array configuration of the UE to a requested antenna array configuration; receiving, from a base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A reconfigured active antenna array with the new antenna array configuration is trained based on the reference signal.

38. A non-transitory computer readable medium storing computer executable code, which, when executed by a processor, causes the processor to: receiving, at a base station, from a user equipment (UE), a request for beam training for a requested antenna array configuration; determining whether to grant or deny the requested antenna array configuration; sending, from the base station, an indication of a new antenna array configuration for the UE and an indication of resources for a reference signal to be used for beam training; as well as A set of reference signals is sent from the base station on the resources.

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