8TX PUSCH fallback to fewer TX PUSCH transmissions

Abstract

Example implementations include a method, an apparatus, and a computer readable medium for wireless communication by a user equipment, the implementations including receiving an indication from a network entity to reduce a number of antenna ports associated with uplink precoding. The implementation also includes transmitting a reference signal to the network entity using the reduced number of antenna ports. The implementation also includes receiving, from the network entity, a message indicating a transmit pre-decoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

Description

Background Art Technical Field

[0001] The present disclosure relates generally to communication systems, and more particularly to uplink transmissions.

[0002] introduction

[0003] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication 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.

[0004] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Certain aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard.

[0005] Further improvements are needed for 5G NR technology. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. For example, it is desirable to improve efficiency and latency related to mobility of user equipment (UE) communicating with network entities. Summary of the invention

[0006] The following presents a simplified overview of one or more aspects in order to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects, and is neither intended to identify key or important elements of all aspects, nor to describe 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 presented later.

[0007] Certain aspects relate to a method for wireless communication at a user equipment. In some examples, the method includes receiving an indication from a network entity to reduce the number of antenna ports associated with uplink precoding. Additionally, in some examples, the method also includes sending a reference signal to the network entity using the reduced number of antenna ports. Additionally, in some examples, the method also includes receiving a message from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0008] Certain aspects relate to a method for wireless communication at a network entity. In some examples, the method includes sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding. Additionally, in some examples, the method also includes receiving a reference signal from the UE using the reduced number of antenna ports. Additionally, in some examples, the method also includes sending a message to the UE indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0009] Certain aspects relate to an apparatus configured for wireless communication, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory, which, when executed by the processor, cause the apparatus to receive an indication from a network entity to reduce the number of antenna ports associated with uplink precoding. In some examples, the instructions, when executed by the processor, also cause the apparatus to send a reference signal to the network entity using the reduced number of antenna ports. In some examples, the instructions, when executed by the processor, also cause the apparatus to receive a message from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0010] Certain aspects relate to an apparatus configured for wireless communication, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory, which, when executed by the processor, cause the apparatus to send an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding. In some examples, the instructions, when executed by the processor, also cause the apparatus to receive reference signals from the UE using the reduced number of antenna ports. In some examples, the instructions, when executed by the processor, also cause the apparatus to send a message to the UE indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0011] Certain aspects relate to a non-transitory computer-readable medium having instructions stored thereon that, when executed by an apparatus, cause the apparatus to perform operations including receiving an indication from a network entity to reduce a number of antenna ports associated with uplink precoding. Additionally, in some examples, the operations include sending reference signals to the network entity using the reduced number of antenna ports. Additionally, in some examples, the operations include receiving a message from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0012] Certain aspects relate to a non-transitory computer-readable medium having instructions stored thereon that, when executed by an apparatus, cause the apparatus to perform operations including sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding. Additionally, in some examples, the operations include receiving reference signals from the UE using the reduced number of antenna ports. Additionally, in some examples, the operations include sending a message to the UE indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0013] Certain aspects relate to an apparatus for wireless communication. In some examples, the apparatus includes means for receiving an indication from a network entity to reduce a number of antenna ports associated with uplink precoding. In some examples, the apparatus includes means for sending a reference signal to the network entity using the reduced number of antenna ports. In some examples, the apparatus includes means for receiving a message from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0014] Certain aspects relate to an apparatus for wireless communication. In some examples, the apparatus includes means for sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding. In some examples, the apparatus includes means for receiving a reference signal from the UE using the reduced number of antenna ports. In some examples, the apparatus includes means for sending a message to the UE indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0015] To achieve the foregoing and related ends, 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 some illustrative features of 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 specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A is a diagram illustrating an example of a wireless communication system and an access network.

[0017] Figure 1B is a diagram illustrating an example of a decomposed base station architecture according to various aspects of the present disclosure.

[0018] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0019] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0020] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0021] Figure 2D is a diagram illustrating an example of UL channels within a subframe according to various aspects of the present disclosure.

[0022] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0023] Figure 4 is a diagram illustrating an example of a call flow between a network entity and a UE according to various aspects of the present disclosure.

[0024] Figure 5 is a diagram illustrating an example of fallback signaling according to the present disclosure.

[0025] Figure 6 is a diagram illustrating an example of fallback signaling according to the present disclosure.

[0026] Figure 7 is a diagram illustrating an example of resources of a reference signal according to the present disclosure.

[0027] Figure 8 is a diagram illustrating an example of resources from multiple resource sets of a reference signal according to the present disclosure.

[0028] Fig. 9 is a diagram illustrating an example of fallback signaling according to the present disclosure.

[0029] Fig.10 is a diagram illustrating an example of resources of a reference signal according to the present disclosure.

[0030] Fig.11 is a diagram illustrating an example of a transmit precoder matrix indicator (TPMI) table.

[0031] Fig.12is a diagram illustrating an example of a hardware implementation for an example apparatus.

[0032] Fig.13 is a flow chart of a wireless communication method.

[0033] Fig.14 is a flow chart of a wireless communication method.

[0034] Fig.15 is a flow chart of a wireless communication method.

[0035] Fig.16 is a flow chart of a wireless communication method.

[0036] Fig.17 is a flow chart of a wireless communication method.

[0037] Fig.18 is a flow chart of a wireless communication method.

[0038] Fig.19 is a flow chart of a wireless communication method.

[0039] Fig. 20 is a flow chart of a wireless communication method.

[0040] Fig.21 is a flow chart of a wireless communication method.

[0041] Fig. 22 is a flow chart of a wireless communication method.

[0042] Fig.23 is a flow chart of a wireless communication method.

[0043] Fig.24 is a diagram illustrating another example of a hardware implementation for another example apparatus.

[0044] Fig.25 is a flow chart of a wireless communication method.

[0045] Fig.26 is a flow chart of a wireless communication method.

[0046] Fig. 27 is a flow chart of a wireless communication method.

[0047] Fig.28 is a flow chart of a wireless communication method.

[0048] Fig.29 is a flow chart of a wireless communication method.

[0049] Fig.30 is a flow chart of a wireless communication method.

[0050] Fig.31is a flow chart of a wireless communication method.

[0051] Fig.32 is a flow chart of a wireless communication method.

[0052] Fig.33 is a flow chart of a wireless communication method. DETAILED DESCRIPTION

[0053] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configuration with which the concepts described herein can be practiced. In order to provide a thorough understanding of the various concepts, the specific embodiments include specific details. However, it is apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid blurring these concepts.

[0054] For uplink transmission, the UE may be configured for codebook-based uplink transmission. In codebook-based uplink transmission, the network entity serving the UE may indicate to the UE a predecoder codebook to be applied to the UE's uplink transmission. The predecoder codebook may be fully coherent, partially coherent, or incoherent. For the full phase predecoder codebook, the radio frequency (RF) and baseband of each antenna port of the UE are turned on. For partially coherent and incoherent codebooks, when the baseband of some of the antenna ports may be turned off, the RF of those antenna ports is still turned on. One of the reasons for this situation is that any of those antenna ports can be used in the next time slot for uplink transmission (e.g., PUSCH). Therefore, the UE is configured to maintain these antenna ports in standby mode by continuing to power on the RF of these antenna ports.

[0055] However, by continuing to power on the RF of such antenna ports, the UE does not effectively save power, and the overall power management of the UE may be suboptimal. Moreover, when uplink traffic is low, this inefficiency in power saving and power management is further exacerbated. Therefore, the techniques described herein allow the UE to save power more efficiently when uplink traffic is low. Figures 4 to 33 Describes additional details of these techniques.

[0056] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0057] As an example, an element or any part of an element or any combination of elements may be implemented as a "processing system", which includes 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, gated logic components, 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. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, etc.

[0058] Therefore, in one or more example embodiments, the described functions can be implemented with hardware, software or any combination thereof. If implemented in software, the function can be stored or encoded on a computer-readable medium as one or more instructions or codes. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media can include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), an optical disk storage device, a magnetic disk storage device, other magnetic storage devices, a combination of computer-readable media of the above type, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0059] Figure 1A is a diagram illustrating an example of a wireless communication system 100 (also referred to as a wireless wide area network (WWAN)) that includes a base station 102 (also referred to herein as a network entity), a user equipment (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)).

[0060] One or more of the UEs 104 may include a fallback component 198, and one or more of the base stations 102 (e.g., network entities) may be configured to include a fallback component 199, wherein the fallback component 198 and the fallback component 199 are operable to reduce power consumption and / or increase power management efficiency of the UEs 104 and base stations 102 (e.g., network entities), respectively.

[0061] At one or more of the UEs 104, and additionally with reference to Fig.12 , the fallback component 198 includes a receiving component 1220, which is configured to receive an indication of reducing the number of antenna ports associated with uplink precoding. In addition, the fallback component 198 includes a sending component 1225, which is configured to send a reference signal using a reduced number of antenna ports. Additionally, the receiving component 1220 may be configured to receive a message indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports. Moreover, in some optional or additional aspects, the fallback component 198 includes: a measurement component 1230, which is configured to measure one or more channel metrics of the reference signal or the second reference signal; and a mapping component 1235, which is configured to map resources indicated in a bitmap or by a value in a DCI message to a set of antenna port identifiers based on the one or more channel metrics and the number of antenna ports.

[0062] For example, refer to Figures 4 to 23 Additional details are provided for the fallback component 198 and / or any of the aforementioned components.

[0063] At one or more of the base stations 102 (or network entities), and additionally with reference to Fig.24 , the fallback component 199 includes a transmitting component 2420 configured to transmit an indication of reducing the number of antenna ports associated with uplink precoding. In addition, the fallback component 199 includes a receiving component 2425 configured to receive a reference signal using the reduced number of antenna ports. Additionally, the transmitting component 2420 can be configured to transmit a message indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports. In the following, for example, reference Figures 4 to 11 and Figures 24 to 33 Additional details are provided for the fallback component 199 and / or any of the aforementioned components.

[0064] Base station (or network entity) 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femto cells, pico cells, and micro cells. Base station 102 may be configured as a decomposed RAN (D-RAN) or open RAN (O-RAN) architecture, in which functionality is split between multiple units (such as a central unit (CU), one or more distributed units (DUs), or radio units (RUs)). Such an architecture may be configured to utilize a protocol stack that is logically split between one or more units (such as one or more CUs and one or more DUs). In some aspects, a CU may be implemented within an edge RAN node, and in some aspects, one or more DUs may be co-located with a CU, or may be geographically distributed in one or more RAN nodes. A DU may be implemented to communicate with one or more RUs. Any of the decomposed components in the D-RAN and / or O-RAN architectures may be referred to as a network entity herein.

[0065] The base station 102 configured for 4G Long Term Evolution (LTE) (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G New Radio (NR) (collectively referred to as Next Generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. Among other functions, the base station 102 can also perform one or more of the following functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (eg, via the EPC 160 or the core network 190) via the third backhaul link 134 (eg, an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0066] Base station 102 can communicate wirelessly with UE 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may 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 may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). A communication link 120 between base station 102 and UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from base station 102 to UE 104. The communication link 120 may use multiple input multiple output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link may be through one or more carriers. For each carrier allocated in the carrier aggregation for up to a total of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 can use a spectrum with a bandwidth of up to Y megahertz (MHz) (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These 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).

[0067] 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). D2D communication may be through a variety of wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0068] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in, for example, a 5 gigahertz (GHz) unlicensed spectrum. 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 prior to communication.

[0069] The small cell 102' may operate in licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) 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.

[0070] 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 range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as the “sub-6 GHz” band in various documents and articles. A similar naming issue sometimes occurs with respect to FR2, which is often (interchangeably) referred to as the “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0071] In view of the above aspects, unless otherwise specifically stated, it should be understood that if used in this article, the term "below 6 GHz" or the like can broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, it should be understood that if the term "millimeter wave" or the like is used in this article, it can broadly represent frequencies that can include mid-band frequencies, can be within FR2, or can be within the EHF band.

[0072] The base station 102, whether a small cell 102' or a large cell (e.g., a macro base station), may include and / or be referred to as an eNB, a gNodeB (gNB), or another type of base station. Some base stations, such as gNB 180, may operate in the traditional sub-6 GHz spectrum, in millimeter wave frequencies, and / or near millimeter wave frequencies to communicate with the UE 104. When the gNB 180 operates in millimeter wave or near millimeter wave frequencies, the gNB 180 may be referred to as a millimeter wave base station. The millimeter wave base station 180 may utilize beamforming 182 with the UE 104 to compensate for path loss and short range. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming.

[0073] Base station 180 may transmit beamformed signals in one or more transmit directions 182′ to UE 104. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182″. UE 104 may also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beam training to determine the optimal receive direction and transmit direction for each of base station 180 / UE 104. The transmit direction and receive direction of base station 180 may be the same or different. The transmit direction and receive direction of UE 104 may be the same or different.

[0074] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, an 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 handles signaling between the UE 104 and the EPC 160. Generally speaking, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are passed 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 functions for MBMS user service configuration and delivery. BM-SC 170 may serve as an entry point for content provider MBMS delivery, may be used to authorize and initiate MBMS bearer services in a public land mobile network (PLMN), and may be used to schedule MBMS delivery. MBMS gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area of ​​a broadcast specific service, and may be responsible for session management (start / stop) and for collecting eMBMS related billing information.

[0075] The core network 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 (UPF) 195. The AMF 192 may communicate with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Typically, the AMF 192 provides quality of service (QoS) flow and session management. All user IP packets are delivered through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IMS, a packet switching (PS) streaming service, and / or other IP services.

[0076] A base station may include and / or be referred to as a network entity, gNB, Node B, eNB, access point, base transceiver station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmit receive point (TRP), or some other suitable term. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare equipment, implants, sensors / actuators, displays, or any other similarly functional device. Some of UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, ovens, vehicles, monitors, cameras, industrial / manufacturing equipment, appliances, vehicles, robots, drones, etc.). IoT UEs may include machine type communication (MTC) / enhanced MTC (eMTC, also referred to as Category (CAT)-M, Cat M1) UEs, NB-IoT (also referred to as CATNB1) UEs, and other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or be based on these technologies. For example, eMTC may include FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), 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 present disclosure may focus on 5G NR, the concepts and aspects described herein may be applicable to other similar areas such as LTE, Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), and / or other wireless / radio access technologies.

[0078] Figure 1B1 is a diagram illustrating an example of a decomposed base station 101 architecture, any component or element of which may be referred to herein as a network entity. The decomposed base station 101 architecture may include one or more central units (CUs) 103, which may communicate directly with a core network 105 via a backhaul link, or indirectly with the core network 105 through one or more decomposed base station units (such as a near real-time (near RT) RAN intelligent controller (RIC) 107 via an E2 link, or a non-real-time (non-RT) RIC 109 associated with a service management and orchestration (SMO) framework 111, or both). The CU 103 may communicate with one or more distributed units (DUs) 113 via corresponding midhaul links (such as an F1 interface). The DU 113 may communicate with one or more radio units (RUs) 115 via corresponding fronthaul links. The RU 115 may communicate with corresponding UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served by multiple RUs 115 simultaneously.

[0079] Each of these units (e.g., CU 103, DU 113, RU 115, and near-RT RIC 107, non-RT RIC 109, and SMO framework 111) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally, the unit may include a wireless interface that may include a receiver, a transmitter, or a transceiver (such as a radio frequency (RF) transceiver) that is configured to receive or send signals, or both, to one or more of the other units via a wireless transmission medium.

[0080] In some aspects, CU 103 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 103. CU 103 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 103 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 103 may be implemented to communicate with DU 113 for network control and signaling.

[0081] DU 113 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RU 115. In some aspects, DU 113 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending at least in part on functional splits such as those defined by the Third Generation Partnership Project (3GPP). In some aspects, DU 113 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 113 or with control functions hosted by CU 103.

[0082] The lower layer functionality may be implemented by one or more RUs 115. In some deployments, the RU 115 controlled by the DU 113 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 115 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some specific implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 115 may be controlled by the corresponding DU 113. In some scenarios, this configuration may enable the implementation of the DU 113 and the CU 103 in a cloud-based RAN architecture (such as a vRAN architecture).

[0083] The SMO framework 111 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 111 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 111 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 103, DU 113, RU 115, and near-RT RIC 107. In some specific implementations, the SMO framework 111 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 117) via the O1 interface. Additionally, in some specific implementations, the SMO framework 111 may communicate directly with one or more RUs 115 via the O1 interface. The SMO framework 111 may also include a non-RT RIC 109 configured to support the functionality of the SMO framework 111 .

[0084] The non-RT RIC 109 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 107. The non-RT RIC 109 may be coupled to or communicate with the near-RT RIC 107 (such as via an A1 interface). The near-RT RIC 107 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 103, one or more DUs 113, or both, and the O-eNB with the near-RT RIC 107.

[0085] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 107, the non-RT RIC 109 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 107 and may be received from a non-network data source or from a network function at the SMO framework 111 or the non-RT RIC 109. In some examples, the non-RT RIC 109 or the near-RT RIC 107 may be configured to adjust RAN behavior or performance. For example, the non-RT RIC 109 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 111 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0086] FIG. 2A to FIG. 2D is a diagram of various frame structures, resources, and channels used by UE 104 and base station 102 / 180 for communications. 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 an UL channel within a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD) (wherein for a particular set of subcarriers (carrier system bandwidth), a subframe within the subcarrier set is dedicated to either DL or UL), or may be time division duplex (TDD) (wherein for a particular set of subcarriers (carrier system bandwidth), a subframe within the subcarrier set is dedicated to both DL and UL). Figure 2A , Figure 2C In the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (most of which are DL), where D is DL, U is UL, and F is flexible between DL / UL, and subframe 3 is configured with slot format 34 (most of which are UL). Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe can be configured with any of the various available slot formats 0 to 61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2 to 61 include a mix of DL, UL and flexible symbols. The UE is configured with the slot format through the received slot format indicator (SFI) (dynamically configured through DL control information (DCI) or semi-statically / statically configured through radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0087] Other wireless communication technologies may have different frame structures and / or different channels. For example, a 10 millisecond (ms) frame may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Each time slot may contain 7 or 14 symbols, depending on the time slot configuration. 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) orthogonal frequency division multiplexing (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-constrained scenarios; limited to single-stream transmission). The number of time slots in a subframe is based on the time slot configuration and parameter set. For slot configuration 0, different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and parameter set 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 parameter set. The subcarrier spacing can be equal to 2 μ *15 kilohertz (kHz), where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15 kHz, and the subcarrier spacing for parameter set μ=4 is 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIG. 2A to FIG. 2D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP can have a specific set of parameters.

[0088] 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 number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0089] like Figure 2A As illustrated, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) for channel estimation at the UE (indicated as R for a particular configuration). x, where 100x is the port number, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS). RS may also include beam measurement RS (BRS), beam refinement RS (BRRS) and phase tracking RS (PT-RS).

[0090] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. The PDCCH within a BWP may be referred to as a control resource set (CORESET). Additional BWPs may be located at higher and / or lower frequencies on the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a specific subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identification. The secondary synchronization signal (SSS) may be within symbol 4 of a specific subframe of a frame. The SSS is used by the UE to determine the physical layer cell identification group number and radio frame timing. Based on the physical layer identification and the physical layer cell identification group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the position of the aforementioned 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 (also referred to as an SS block (SSB)). 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 over the PBCH (such as the system information block (SIB)), and paging messages.

[0091] like Figure 2C As illustrated, some of the REs carry DM-RS (indicated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may send a DM-RS for a physical uplink control channel (PUCCH) and a DM-RS for a physical uplink shared channel (PUSCH). The PUSCH DM-RS may be sent in the first or first 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 may be sent in different configurations. The UE may send a sounding reference signal (SRS). The SRS may be sent in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0092] Figure 2DExamples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position 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 hybrid automatic repeat request (HARQ) acknowledgement (ACK) / negative acknowledgement (NACK) feedback. The PUSCH carries data and may be used to carry, among other things, a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0093] Figure 3 1 is a block diagram of hardware components of base station 102 (and / or 180) in wireless communication system 100 for communicating with UE 104. In the DL, IP packets from EPC 160 may be provided to controller / processor 375. Controller / processor 375 implements layer 3 and layer 2 functions. 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 delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation 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 handling, and logical channel prioritization.

[0094] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include error detection on the transmission channel, forward error correction (FEC) decoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-order phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The decoded and modulated symbols can then be divided into parallel streams. Subsequently, each stream can be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially pre-coded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived from reference signals and / or channel state feedback sent by the UE 104. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0095] At the UE 104, each receiver 354RX receives a signal through its corresponding 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 streams destined for the UE 104. If multiple spatial streams are destined for the UE 104, 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 on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point sent by the base station 102. 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 102. The data and control signals are then provided to a controller / processor 359, which implements layer 3 and layer 2 functionality.

[0096] 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.

[0097] Similar to the functions described in conjunction with DL transmissions performed by the base station 102, 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 functionality associated with delivery 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 handling, and logical channel prioritization.

[0098] The TX processor 368 may use channel estimates derived by the channel estimator 358 from a reference signal or feedback sent by the base station 102 to select 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 corresponding transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0099] UL transmissions are processed at the base station 102 in a manner similar to that described in conjunction with the receiver functionality at the UE 104. 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.

[0100] 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 channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 104. 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.

[0101] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform a combined Figure 1A Aspects of the rollback component 198.

[0102] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform a combined Figure 1A Aspects of the fallback component 199.

[0103] refer to Figure 4 , example 400 illustrates a call flow between a network entity and a UE for backoff signaling to a smaller number of antenna ports. As described above, the network entity 102 may determine whether uplink traffic from the UE 102 is low, and in response, send a backoff signal to the UE to reduce the number of antenna ports. For example, the network entity 102 may determine whether the uplink traffic is below a threshold uplink traffic volume or level for a threshold time period (e.g., a threshold number of time slots, a threshold duration, etc.).

[0104] At communication 402, based on determining that the UL traffic from the UE 104 is low, the network entity 102 can be configured to send a fallback signal and / or indication to the UE 104 to reduce the number of antenna ports associated with uplink precoding. For example, if the UE 104 is configured with 8 antenna ports for transmitting uplink data and / or signals (e.g., 8 transmit (Tx) PUSCH), the network entity 102 can send a fallback signal to the UE 104 to reduce the number of antenna ports to less than 8 antenna ports for uplink data and / or signals (e.g., 4 antenna ports (4Tx PUSCH), 2 antenna ports (2Tx PUSCH), 1 antenna port (e.g., 1Tx PUSCH)).

[0105] In some implementations, the network entity 102 can implicitly send a fallback signal and / or indication to the UE 104. For example, the network entity 102 can implicitly indicate or signal a fallback to fewer antenna ports for uplink data and / or signals by sending a configuration for resources associated with a reference signal. For example, the network entity 102 can send a configuration for a sounding reference signal (SRS) resource via an RRC message, where the configuration indicates an SRS with a new set of antenna ports. Figure 5 Example 500 illustrates such a backoff signal and / or indication.

[0106] exist Figure 5 In example 500 of FIG. 4 , UE 104 may have been configured with reference signal resources (e.g., SRS resources) associated with 8 antenna ports (e.g., 8 SRS ports) of UE 104, as indicated by configuration 502, for sending reference signals to a network entity. At communication 402, network entity 102 may send configuration 504 of resources (e.g., SRS resources) for reference signals. Configuration 504 may indicate that the reference signal resources are associated with fewer antenna ports than the resources for the reference signal that UE 104 may have been previously configured with via configuration 502. For example, configuration 504 may indicate that the reference signal resources (e.g., SRS resources) are associated with 4 antenna ports (e.g., 4 SRS ports).

[0107] UE 104 may determine whether the communication at 402 from the network entity is a backoff signal and / or indication as to whether the number of associated antenna ports indicated in configuration 504 is less than the number of antenna ports associated with resources (e.g., SRS resources) that UE 104 has been configured with via configuration 502. In example 500, since the number of antenna ports in configuration 504 (4 antenna ports) is less than the number of antenna ports in configuration 502, UE 104 determines that the communication at 402 is a backoff signal and / or indication to reduce the number of antenna ports associated with uplink precoding and / or used for uplink data and / or signals to 4 antenna ports.

[0108] In example 500, configuration 504 may indicate antenna port identifiers for 4 ports and refer back to Figure 4 At block 404 , the UE 104 may determine and / or identify a reduced set of antenna port identifiers for antenna ports based on the antenna port identifiers indicated in the configuration 504 .

[0109] In some specific implementations, Figure 4At communication 402 in FIG. 4 , the network entity 102 may explicitly send a fallback signal and / or indication to the UE 104. In some implementations, the network entity 102 may explicitly indicate or signal a fallback to fewer antenna ports for uplink data and / or signals by indicating a switch between different resources (e.g., SRS resources) of a reference signal (e.g., SRS). Different resources of reference signals may be configured with different numbers of antenna ports. The network entity 102 may send such a fallback signal and / or indication via a MAC CE message or a DCI message.

[0110] exist Figure 6 An example of explicitly indicating or signaling a fallback via a MAC CE message is shown in example 600. In example 600, a bitmap 602 may be included in a MAC CE message. The bitmap 602 in example 600 may include a plurality of bits, such as bits 604, 606, 608, 610, 612. Each of bits 604, 606, 608, 610, 612 may correspond to a different resource (e.g., SRS resource) of a reference signal (e.g., SRS). In some implementations, the UE 104 may be configured with a single resource set (e.g., an SRS resource set) having one or more resources (e.g., SRS resources), and the bitmap 602 may be associated with the single resource set and each of bits 604, 606, 608, 610, 612 may correspond to a different resource in the resource set. In some implementations, the UE 104 may be configured with multiple resource sets (e.g., multiple SRS resource sets), each of the multiple resource sets having one or more resources (e.g., SRS resources), and the bitmap 602 may be associated with the multiple resource sets and each of the bits 604, 606, 608, 610, 612 may correspond to a different resource from a different resource set.

[0111] exist Figure 7An example of a UE 104 being configured with a single resource set having multiple resources is shown in example 700 of . In example 700, the network entity 102 may configure the UE 104 to have a resource set 702. The resource set 702 may be an SRS resource set. The resource set 702 may include multiple resources (e.g., SRS resources) 704, 706. Different resources 704, 706 may be configured with and / or associated with different numbers of antenna ports (e.g., SRS antenna ports, PUSCH antenna ports, etc.). For example, as shown in example 700, the resource 704 may be configured with and / or associated with 8 antenna ports (e.g., SRS antenna ports, PUSCH antenna ports), and the resource 706 may be configured with and / or associated with 4 antenna ports (e.g., SRS antenna ports, PUSCH antenna ports). The network entity 102 may configure the UE 104 to have a single resource set via a configuration of the resource set 702 transmitted from the network entity 102. UE 104 may receive a configuration for resource set 702 via an RRC message.

[0112] Continuing with the above example, Figure 6 The bitmap 602 in the bitmap 602 may be associated with the resource set 702, and the bit 604 may correspond to the resource 704 and the bit 606 may correspond to the resource 706. The network entity 102 may send a backoff signal and / or indication of reducing the number of antenna ports via the bitmap 602. For example, based on the UL traffic, if the network entity 102 determines that the UE 104 can fall back to 4 antenna ports, the network entity 102 may send the backoff signal and / or indication by setting the bit 606 in the bitmap 602 and send the bitmap 602 via a MAC CE message.

[0113] As described above, UE 104 may be configured with multiple resource sets (e.g., multiple SRS resource sets), each of which has one or more resources (SRS resources). Figure 8 An example of a UE 104 being configured with such multiple resource sets is shown in example 800 of FIG. 1 . In example 800, the network entity 102 may configure the UE 104 with resource sets 802a, 802b. The resource sets 802a, 802b may be SRS resource sets. Each of the resource sets 802a, 802b may include one or more resources (e.g., SRS resources). For example, Figure 8As shown, resource set 802a may include resources (e.g., SRS resources) 804, and resource set 802b may include resources (e.g., SRS resources) 806, 808. Different resources 804, 806, 808 may be configured with and / or associated with different numbers of antenna ports (e.g., SRS antenna ports, PUSCH antenna ports, etc.). For example, as shown in example 800, resource 804 in resource set 802a may be configured with and / or associated with 8 antenna ports (e.g., SRS antenna ports, PUSCH antenna ports). Similarly, resources 806, 808 in resource set 802b may be configured with and / or associated with 4 antenna ports (e.g., SRS antenna ports, PUSCH antenna ports). The network entity 102 may configure the UE 104 to have multiple resource sets via configuration of multiple resource sets 802a, 802b transmitted from the network entity 102. The UE 104 may receive configurations for the resource sets 802a, 802b via an RRC message.

[0114] Figure 6 The bitmap 602 in the bitmap 602 may be associated with the resource sets 802a, 802b, and the bit 608 may correspond to the resource 804, the bit 610 may correspond to the resource 806, and the bit 612 may correspond to the resource 808. As described above, the network entity 102 may send a backoff signal and / or indication of reducing the number of antenna ports via the bitmap 602. For example, based on the UL traffic, if the network entity 102 determines that the UE 104 can fall back to 4 antenna ports and select the resource 808 from the resource set 802b, the network entity 102 may send the backoff signal and / or indication by setting the corresponding bit 612 in the bitmap 602, and send the bitmap 602 via the MAC CE message.

[0115] exist Fig. 9 An example of explicitly indicating or signaling a fallback via a DCI message is shown in example 900 of . In example 900, a table 902 is shown with different values ​​(e.g., SRS resource indicator (SRI) values, etc.) that can be in a DCI message. Each value in table 902 can correspond to a different reference signal resource (e.g., SRS resource). For example, value 904 can correspond to resource 704, value 906 can correspond to resource 706, value 908 can correspond to resource 806, and value 910 can correspond to resource 808. Similarly, other values ​​in the DCI (e.g., SRI values) can correspond to other resources configured with different numbers of antenna ports (e.g., 2 antenna ports, 1 antenna port, etc.). The network entity 102 can include one of the values ​​in table 902 in a DCI message sent to the UE 104 to indicate and / or signal to the UE 104 a fallback to fewer antenna ports for uplink data and / or signals.

[0116] Return to reference Figure 4 At block 404, the UE 104 may determine and / or map a set of antenna port identifiers for the UE 104 for the resources indicated by the network entity in the backoff signal and / or indication of the communication 402. In some implementations, the antenna port identifiers for the resources may be indicated and / or included in the configuration of the resources received by the UE 104. For example, the configuration of the resources 704, 706, 804, 806, 808 and / or a configuration associated therewith may indicate and / or include an antenna port identifier for each of the resources 704, 706, 804, 806, 808. For example, the configuration for the resources 704, 706 may indicate a set of antenna port identifiers 1, 2, 3, 4, 5, 6, 7, 8 for the resource 704 and / or may indicate a set of antenna port identifiers 1, 2, 3, 4 for the resource 706. Similarly, the configuration for 804 may indicate a set of antenna port identifiers 1, 2, 3, 4, 5, 6, 7, 8, and the configuration for resources 806, 808 may indicate a set of antenna port identifiers 1, 3, 4, 7 for resource 806 and antenna port identifiers 2, 5, 6, 8 for resource 808.

[0117] In some implementations, the UE 104 may be configured to autonomously determine and / or map a set of antenna port identifiers of the UE 104 based on channel metrics of reference signals that the UE 104 may receive from the network entity 102. Examples of channel metrics may include, but are not limited to, reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), signal to interference and noise ratio (SINR), etc. Examples of reference signals based on which the UE 104 measures channel metrics may be, but are not limited to, CSI reference signals (CSI-RS), etc. For example, the UE 104 may receive a reference signal (such as a CSI-RS) from the network 102 at an antenna port (e.g., a receive (Rx) port) of the UE 104, and the UE 104 may measure and / or determine channel metrics one or more of RSRP, RSSI, SINR, etc. based on the received CSI-RS. The UE 104 may receive such reference signals at different antenna ports, and measure and / or determine channel metrics at the different antenna ports based on the reference signals received at the different antenna ports.

[0118] In a specific implementation where the UE 104 is configured to autonomously determine and / or map a set of antenna port identifiers for the UE 104, the configuration of resources (e.g., SRS resources) may indicate the number of antenna ports used for each of the resources. For example, configuring resources 704, 706 may indicate and / or include 8 antenna ports for resource 704 and 4 antenna ports for resource 706. Similarly, the configuration for resource 804 may indicate and / or include 8 antenna ports, the configuration for resource 806 may indicate and / or include 4 antenna ports, and the configuration for resource 808 may indicate and / or include 4 antenna ports.

[0119] The UE 104 may autonomously determine and / or map antenna port identifiers based on one or more channel metrics of a received reference signal (e.g., a received CSI-RS) and a corresponding number of antenna ports indicated and / or included in a configuration of a resource. In some implementations, the UE 104 may be configured to determine and / or identify antenna ports with the best channel metrics and map corresponding numbers of antenna ports to the resource based on corresponding numbers of antenna ports indicated and / or included in a configuration of a resource (e.g., an SRS resource). For example, if Figure 4 At communication 402 in , the network entity sends a fallback indication and / or signal by sending an indication to switch to resource 706, and its configuration indicates and / or includes the number of antenna ports as four, then UE 104 can identify the four best RSRP values ​​(or any other channel metric described above) and select their corresponding and / or associated antenna ports to map to resource 706.

[0120] In some implementations, the UE 104 may be configured with one resource for a reference signal, and the resource may be configured with multiple antenna ports of the UE 104. Fig.10 An example of such resource configuration is shown in example 1000 of . In example 1000, UE 104 may be configured with resources (e.g., SRS resources) 1002. Resources 1002 may be configured with and / or associated with antenna ports 1004, 1006, 1008, 1010, 1012, 1014, 1016, 1018. Figure 4At communication 402 in FIG. 4 , the network entity 102 may indicate or signal a fallback to fewer antenna ports for uplink data and / or signals by indicating the number of antenna ports to fallback to by the UE 104. For example, the network entity 102 may send a message (e.g., a MAC CE, a DCI, etc.) to the UE 104 that indicates and / or includes four as the number of antenna ports to fall back to. Similarly, the network entity 102 may indicate and / or include two, one, or any other number and / or value in the message as the number of antenna ports to fall back to by the UE 104.

[0121] Based on the indicated number of antenna ports to fall back to, Figure 4 At block 404 of , the UE 104 may determine and / or identify the corresponding antenna port identifier. In some implementations, the UE 104 may determine and / or identify the corresponding antenna port identifier based on one or more channel metrics (e.g., RSRP, RSSI, SINR, etc.) of the received reference signal (e.g., CSI-RS), as described above.

[0122] In some implementations, the network entity 102 may explicitly indicate a set of antenna port identifiers corresponding to the indicated number of antenna ports via a bitmap sent to the UE 104. In some implementations, the set of bits in the bitmap may correspond to the set of antenna port identifiers, and each bit in the set of bits may correspond to a respective antenna port identifier in the set of antenna port identifiers. In some implementations, the number of bits in the set of bits may correspond to the number of antenna ports with which the UE 104 is configured. For example, if the UE 104 is configured with 8 antenna ports, the corresponding set of bits in the bitmap may include 8 bits, one bit for each of the 8 antenna ports. In some implementations, the bitmap may be bitmap 602, and the set of bits may be Figure 6 Additional bits of bitmap 602 are shown in FIG.

[0123] In some implementations, the network entity 102 may explicitly indicate a set of antenna port identifiers corresponding to the indicated number of antenna ports via a DCI message sent to the UE 104. In some implementations, the DCI message may include a field or a reserved set of bits configured to indicate the antenna port identifiers. For example, if the number of antenna ports to fall back to is four, the network entity 102 may indicate four antenna port identifiers via the field or via the reserved set of bits.

[0124] The UE 104 may be configured to increase or maintain the same transmit power (e.g., TxPower) for each antenna port in the antenna ports to which the UE 104 falls back or for each antenna port mapped to the resource 1002. For example, in the example 1000, if the network entity 102 instructs the UE 104 to fall back to 4 antenna ports, the UE 104 may increase the transmit power of each antenna port in the 4 mapped antenna ports by 3 dB so that the UE 104 may apply the pre-decoder codebook. Where a, b, c, d can be any value for sending uplink transmission. Alternatively, UE 104 can maintain the same transmit power for each of the 4 mapped antenna ports so that UE 104 can apply the pre-decoder codebook

[0125] Return to reference Figure 4 At communication 406, UE 104 may be configured to send a reference signal using the reduced and mapped antenna port identifiers to network entity 102. As described above, the reference signal may be an SRS and / or any other reference signal based on which network entity 102 may measure and / or estimate a channel metric.

[0126] At block 408, the network entity 102 may be configured to select a pre-decoder codebook, a corresponding TPMI, and / or a corresponding rank and / or layer. The network entity 102 may measure and / or estimate a channel metric based on a reference signal received from the UE 104 at communication 406. The network entity 102 may select a pre-decoder codebook, a corresponding TPMI, and / or a corresponding rank and / or layer based on the measured and / or estimated channel metric and the number of antenna ports used by the UE 104 to send a reference signal (e.g., SRS) and / or the number of antenna ports indicated and / or signaled at communication 402 to which the UE 104 falls back.

[0127] Different numbers of antenna ports may be associated with different numbers of predecoder codebooks. Different predecoder codebooks may be nested and / or may be subsets of other predecoder codebooks. For example, a predecoder codebook for one antenna port (e.g., 1Tx predecoder codebook) may be nested in a predecoder codebook for two antenna ports (e.g., 2Tx predecoder codebook) and / or may be a subset thereof, a predecoder codebook for two antenna ports (e.g., 2Tx predecoder codebook) may be nested in a predecoder codebook for four antenna ports (e.g., 4Tx predecoder codebook) and / or may be a subset thereof, and a predecoder codebook for four antenna ports (e.g., 4Tx predecoder codebook) may be nested in a predecoder codebook for eight antenna ports (e.g., 8Tx predecoder codebook) and / or may be a subset thereof.

[0128] An example of a rank one or one layer precoder codebook for eight antenna ports (e.g., 8Tx precoder rank 1) may be Where each of a, b, c, d, e, f, g, h can be any value (e.g., 1, -1, j, -j, etc.); an example of a rank one or one layer precoder codebook for four antenna ports (e.g., 4Tx precoder rank 1) can be Where each of m, p, t, u can be any value (e.g., 1, -1, j, -j, etc.); an example of a rank one or one layer precoder codebook for two antenna ports (e.g., 2Tx precoder rank 1) can be Where each of x and y can be any value (e.g., 1, -1, j, -j, etc.); an example of a rank one or one layer pre-decoder codebook for one antenna port (e.g., 1Tx pre-decoder rank 1) can be Where z can be any value (e.g., 1, -1, j, -j, etc.). In some implementations, the UE 104 can be configured to turn off the RF and baseband of the antenna ports of the UE 104 corresponding to the zero elements in the predecoder codebook. For example, in the above predecoder codebook, if the first row of the matrix of the predecoder codebook corresponds to the first antenna port and / or the antenna port with identifier 1, and if the second row corresponds to the second antenna port and / or the antenna port with identifier 2, etc., then if the UE 104 receives an indication of the above example codebook for four antenna ports (e.g., TPMI index), the UE 104 can turn off the RF and baseband of antenna ports 5, 6, 7, and 8. Similarly, if UE 104 receives an indication of the above example codebook for two antenna ports (e.g., TPMI index), UE 104 can turn off RF and baseband of antenna ports 3, 4, 5, 6, 7, and 8, and if UE 104 receives an indication of the above example codebook for one antenna port (e.g., TPMI index), UE 104 can turn off RF and baseband of antenna ports 2, 3, 4, 5, 6, 7, and 8.

[0129] In some implementations, different pre-decoder codebooks may share the TPMI table. Fig.11 An example of different pre-decoder codebooks sharing a TPMI table is shown in example 1100 in FIG. Fig.11In example 1100 of , the TPMI table 1102 may include predecoder codebooks for different numbers of antenna ports. For example, in row 1104, the TPMI table 1102 may include predecoder codebooks for two antenna ports (e.g., 2Tx predecoder codebooks). Similarly, in row 1106, the TPMI table may include predecoder codebooks for four antenna ports (e.g., 4Tx predecoder codebooks). In table 1102, the two-antenna port predecoder codebook is nested in the four-antenna port predecoder codebook and / or is a subset thereof. In some implementations, the coefficients of all predecoder codebooks in the TPMI table may be the same. In some implementations, the coefficients of one set of predecoder codebooks in the TPMI table may be the same, another set of predecoder codebooks may be different, a third set of predecoder codebooks may be different from the other two sets of predecoder codebooks, and so on.

[0130] The TPMI table 1102 may include a TPMI index 1110. Each value of the TPMI index may correspond to a precoder codebook in the TPMI table 1102. For example, TPMI index 0 may correspond to the leftmost precoder codebook in row 1104 of the TPMI table 1102, and TPMI index 7 may correspond to the rightmost precoder codebook in row 1104 of the TPMI table 1102, and TPMI indexes 1 to 6 may correspond to relative precoder codebooks between the leftmost precoder codebook and the rightmost precoder codebook in row 1104. Similarly, TPMI index 8 may correspond to the leftmost precoder codebook in row 1106, TPMI index 15 may correspond to the rightmost precoder codebook in row 1106, and TPMI indexes 9 to 14 may correspond to relative precoder codebooks between the leftmost precoder codebook and the rightmost precoder codebook in row 1106.

[0131] Return to reference Figure 4 At communication 410, the network entity 102 may send a control signal indicating the corresponding TPMI index of the selected pre-decoder codebook and / or the selected TPMI index. As described above, the selected TPMI index may be based on and / or associated with the number of antenna ports that the UE 104 backed off based on the communication 402 from the network entity 102. The network entity 102 may indicate the selected TPMI index to the UE 104 in a message. The UE 104 transmits uplink data and / or signals (e.g., PUSCH transmissions) to the network entity 102 using the pre-decoder codebook indicated by the TPMI index and using antenna ports mapped to resources (e.g., SRS resources) of the transmitted reference signal (e.g., SRS).

[0132] refer to Fig.12 Example 1200 and Fig.13In operation, UE 104 may, for example, communicate with processor 1205 and / or memory 360 ( Figure 3 ) performs the method 1300 of wireless communication by executing the fallback component 198. In this case, the processor 1205 can be the above Figure 3 The receive (rx) processor 356, controller / processor 359 and / or transmit (tx) processor 368 described in FIG.

[0133] At block 1302, method 1300 includes receiving an indication from a network entity to reduce the number of antenna ports associated with uplink precoding. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or receiving component 1220 may be configured to receive an indication from a network entity to reduce the number of antenna ports associated with uplink precoding, or may include means for receiving an indication from a network entity to reduce the number of antenna ports associated with uplink precoding.

[0134] For example, the receiving at block 1302 may include: Figure 3 The indication is received via a wireless signal at an antenna or antenna array (e.g., antenna 352) described in, and the received wireless signal and the indication are processed as described above.

[0135] At block 1304, method 1300 includes sending a reference signal to a network entity using the reduced number of antenna ports. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or receiving component 1220 may be configured to send a reference signal to a network entity using the reduced number of antenna ports, or may include means for sending a reference signal to a network entity using the reduced number of antenna ports.

[0136] For example, the sending at block 1304 may include sending Figure 3 The reference signal is sent via a wireless signal at an antenna or antenna array (e.g., antenna 352) described in FIG.

[0137] At block 1306, method 1300 includes receiving a message from a network entity indicating a transmit pre-decoder matrix indicator (TPMI) associated with a reduced number of antenna ports. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or receiving component 1220 may be configured to receive a message from a network entity indicating a transmit pre-decoder matrix indicator (TPMI) associated with a reduced number of antenna ports, or may include means for receiving a message from a network entity indicating a transmit pre-decoder matrix indicator (TPMI) associated with a reduced number of antenna ports.

[0138] For example, the receiving at block 1306 may include: Figure 3 The message indicating the TPMI is received via a wireless signal at an antenna or antenna array (eg, antenna 352) described in , and the received wireless signal and the message indicating the TPMI are processed as described above.

[0139] In an alternative or additional aspect, the indication is received via a radio resource control (RRC) message.

[0140] In an alternative or additional aspect, the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on the number of antenna ports in the antenna port set.

[0141] In alternative or additional aspects, the indication is received via a bitmap in a MAC CE message, or wherein the indication is received via a value in a DCI message.

[0142] In alternative or additional aspects, each bit in the bitmap corresponds to a resource from a set of resources associated with a reference signal, or wherein the value corresponds to a resource from a set of resources associated with a reference signal.

[0143] refer to Fig.14 In an alternative or additional aspect, at block 1402, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with a reference signal or wherein the value corresponds to a resource from a set of resources associated with a reference signal, the method 1300 may further include receiving, from a network entity, a configuration indicating a set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the fallback component 198, and / or the receiving component 1220 may be configured to receive, or may include means for receiving, from a network entity, a configuration indicating a set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message.

[0144] For example, the receiving at block 1402 may include: Figure 3 The antenna or antenna array (e.g., antenna 352) described in the embodiment receives a wireless signal via a configuration, and processes the received wireless signal and a third configuration, as described above.

[0145] refer to Fig.15In an alternative or additional aspect, at block 1502, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal or wherein the value corresponds to a resource from a set of resources associated with the reference signal, the method 1300 may also include receiving a second reference signal from a network entity and a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the backoff component 198, and / or the receiving component 1220 may be configured to receive a second reference signal from a network entity and a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources, or may include means for receiving a second reference signal from a network entity and a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources.

[0146] For example, the receiving at block 1502 may include: Figure 3 The second reference signal is received via a wireless signal at the antenna or antenna array described in (e.g., antenna 352), and the received wireless signal and the second reference signal are processed as described above.

[0147] In this optional aspect, at block 1504, method 1300 may further include measuring one or more channel metrics for the second reference signal. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or measuring component 1230 may be configured to measure one or more channel metrics for the second reference signal, or may include means for measuring one or more channel metrics for the second reference signal.

[0148] In this optional aspect, at block 1506, the method 1300 may further include mapping resources indicated in the bitmap or indicated by a value in the DCI message to a set of antenna port identifiers based on one or more channel metrics and the number of antenna ports, wherein the reduced number of antenna ports is based on the set of antenna port identifiers. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the fallback component 198, and / or the mapping component 1235 may be configured to map resources indicated in the bitmap or indicated by a value in the DCI message to a set of antenna port identifiers based on one or more channel metrics and the number of antenna ports, or may include means for mapping resources indicated in the bitmap or indicated by a value in the DCI message to a set of antenna port identifiers based on one or more channel metrics and the number of antenna ports, wherein the reduced number of antenna ports is based on the set of antenna port identifiers.

[0149] In alternative or additional aspects, each bit in the bitmap corresponds to a resource from a set of resources in a plurality of sets of resources associated with the reference signal, or wherein the value corresponds to a resource from a set of resources in a plurality of sets of resources associated with the reference signal.

[0150] refer to Fig.16 , in an alternative or additional aspect, at box 1602, wherein each bit in the bitmap corresponds to a resource from a resource set in a plurality of resource sets associated with a reference signal or wherein the value corresponds to a resource from a resource set in a plurality of resource sets associated with a reference signal, method 1300 may also include receiving, from a network entity, a configuration indicating a plurality of resource sets for the reference signal and a corresponding set of antenna ports for each resource in each resource set from the plurality of resource sets, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the corresponding resource in the resource set indicated in the bitmap or the DCI message. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the back-off component 198 and / or the receiving component 1220 may be configured to receive, or may include components for receiving from a network entity, a plurality of resource sets indicating reference signals and a configuration of a corresponding antenna port set for each resource in each resource set from the plurality of resource sets, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the corresponding resources in the resource set indicated in the bitmap or DCI message.

[0151] For example, the receiving at block 1602 may include: Figure 3 The antenna or antenna array (e.g., antenna 352) described in the embodiment receives a wireless signal via a configuration, and processes the received wireless signal and a third configuration, as described above.

[0152] refer to Fig.17 In an alternative or additional aspect, at block 1702, wherein each bit in the bitmap corresponds to a resource from a set of resources in a plurality of sets of resources associated with the reference signal or wherein the value corresponds to a resource from a set of resources in a plurality of sets of resources associated with the reference signal, the method 1300 may further include receiving, from a network entity, a second reference signal and a configuration of the plurality of resource sets indicating the reference signal. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the fallback component 198, and / or the receiving component 1220 may be configured to receive, or may include means for receiving, from a network entity, a second reference signal and a configuration of the plurality of resource sets indicating the reference signal.

[0153] For example, the receiving at block 1702 may include: Figure 3 The second reference signal and configuration are received via a wireless signal at an antenna or antenna array (eg, antenna 352) described in, and the received wireless signal and the second reference signal and configuration are processed as described above.

[0154] In this optional aspect, at block 1704, method 1300 may further include measuring one or more channel metrics for the second reference signal. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or measuring component 1230 may be configured to measure one or more channel metrics for the second reference signal, or may include means for measuring one or more channel metrics for the second reference signal.

[0155] In this optional aspect, at block 1706, method 1300 may further include mapping corresponding resources in a set of resources indicated in a bitmap or DCI message to a set of antenna port identifiers based on the one or more channel metrics and the number of antenna ports, wherein the reduced number of antenna ports is based on the set of antenna port identifiers. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or mapping component 1235 may be configured to, or may include, components.

[0156] In an alternative or additional aspect, the reference signal is a sounding reference signal (SRS).

[0157] In an alternative or additional aspect, the value is an SRS Resource Indicator (SRI) value indicated in the DCI message.

[0158] In an alternative or additional aspect, the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

[0159] In an alternative or additional aspect, resources for the reference signal are associated with a number of antenna ports equal to the number of antennas of the apparatus, and wherein the same resources are associated with a reduced number of antenna ports.

[0160] refer to Fig.18 In an alternative or additional aspect, at block 1802, wherein resources of the reference signal are associated with a plurality of antenna ports of the device equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 1300 may further include receiving a second reference signal from a network entity. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the backoff component 198, and / or the receiving component 1220 may be configured to receive the second reference signal from the network entity, or may include means for receiving the second reference signal from the network entity.

[0161] For example, the receiving at block 1802 may include: Figure 3 The second reference signal is received via a wireless signal at the antenna or antenna array described in (e.g., antenna 352), and the received wireless signal and the second reference signal are processed as described above.

[0162] In this optional aspect, at block 1804, method 1300 may further include measuring one or more channel metrics for the second reference signal. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or measuring component 1230 may be configured to measure one or more channel metrics for the second reference signal, or may include means for measuring one or more channel metrics for the second reference signal.

[0163] In this optional aspect, at block 1806, method 1300 may further include mapping resources to a set of antenna port identifiers based on the one or more channel metrics and the reduced number of antenna ports. For example, in an aspect, UE 104, processor 1205, memory 360, backoff component 198, and / or mapping component 1235 may be configured to map resources to a set of antenna port identifiers based on the one or more channel metrics and the reduced number of antenna ports, or may include means for mapping resources to a set of antenna port identifiers based on the one or more channel metrics and the reduced number of antenna ports.

[0164] refer to Fig.19 In an alternative or additional aspect, at block 1902, wherein the resources of the reference signal are associated with a plurality of antenna ports of the device that are equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 1300 may further include receiving a set of antenna port identifiers from a network entity via a bitmap in a MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the fallback component 198, and / or the receiving component 1220 may be configured to receive the set of antenna port identifiers from the network entity via a bitmap in a MAC CE message, or may include means for receiving the set of antenna port identifiers from the network entity via a bitmap in a MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers.

[0165] For example, the receiving at block 1902 may include: Figure 3 The antenna or antenna array described in (e.g., antenna 352) receives the set of antenna port identifiers via a wireless signal, and processes the received wireless signal and the set of antenna port identifiers as described above.

[0166] refer to Fig. 20 In an alternative or additional aspect, at block 2002, wherein resources for a reference signal are associated with a plurality of antenna ports of the device that are equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 1300 may further include receiving a set of antenna port identifiers from a network entity via a field or a set of reserved bits in a DCI message. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the fallback component 198, and / or the receiving component 1220 may be configured to receive the set of antenna port identifiers from the network entity via a field or a set of reserved bits in a DCI message, or may include means for receiving the set of antenna port identifiers from the network entity via a field or a set of reserved bits in a DCI message.

[0167] For example, the receiving at block 2002 may include: Figure 3 The antenna or antenna array described in (e.g., antenna 352) receives the set of antenna port identifiers via a wireless signal, and processes the received wireless signal and the set of antenna port identifiers as described above.

[0168] refer to Fig.21 In an alternative or additional aspect, at block 2102, the method 1300 may further include sending a capability report to a network entity, the capability report indicating the capability of the user equipment (UE) to increase the transmit power of each antenna port in the reduced number of antenna ports. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the backoff component 198, and / or the transmitting component 1225 may be configured to send a capability report to the network entity, or may include means for sending a capability report to the network entity, the capability report indicating the capability of the user equipment (UE) to increase the transmit power of each antenna port in the reduced number of antenna ports.

[0169] For example, the sending at block 2102 may include: Figure 3 The capability report is sent via a wireless signal at an antenna or antenna array (e.g., antenna 352) described in.

[0170] refer to Fig. 22 In an alternative or additional aspect, at block 2202, the method 1300 may further include increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the increased transmit power. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the backoff component 198, and / or the transmit power component 1240 may be configured to increase the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, or may include means for increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the increased transmit power.

[0171] refer to Fig.23 In an alternative or additional aspect, at block 2302, the method 1300 may further include refraining from increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the same transmit power per antenna port as that used before the number of antenna ports associated with the uplink pre-coding was reduced. For example, in an aspect, the UE 104, the processor 1205, the memory 360, the back-off component 198, and / or the transmit power component 1240 may be configured to refrain from increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, or may include means for refraining from increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the same transmit power per antenna port as that used before the number of antenna ports associated with the uplink pre-coding was reduced.

[0172] In an alternative or additional aspect, the TPMI is associated with a precoding matrix in at least one precoding matrix table, the at least one precoding matrix table including matrices associated with different numbers of antenna ports.

[0173] In an alternative or additional aspect, the precoding matrix is ​​associated with a reduced number of antenna ports.

[0174] refer to Fig.24 Example 2400 and Fig.25 In operation, the network entity 102 may communicate with the network entity 102 by, for example, via the processor 2405 and / or the memory 376 ( Figure 3 ) performs the method 2500 of wireless communication by executing the fallback component 199. In this case, the processor 2405 can be the above Figure 3 Receive (rx) processor 370, controller / processor 375 and / or transmit (tx) processor 316 as described in.

[0175] At block 2502, method 2500 includes sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding. For example, in an aspect, network entity 102, processor 2405, memory 376, backoff component 199, and / or transmitting component 2420 may be configured to send an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding, or may include means for sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding.

[0176] For example, the sending at block 2502 may include sending Figure 3The indication is sent via a wireless signal at an antenna or antenna array (e.g., antenna 320) described in.

[0177] At block 2504, method 2500 includes receiving a reference signal from the UE using the reduced number of antenna ports. For example, in an aspect, network entity 102, processor 2405, memory 376, backoff component 199, and / or receiving component 2425 may be configured to receive a reference signal from the UE using the reduced number of antenna ports, or may include means for receiving a reference signal from the UE using the reduced number of antenna ports.

[0178] For example, the receiving at block 2504 may include: Figure 3 The reference signal is received via the wireless signal at the antenna or antenna array described in (eg, antenna 320 ), and the received wireless signal and reference signal are processed as described above.

[0179] At block 2506, the method 2500 includes sending a message to the UE indicating a transmit pre-decoder matrix indicator (TPMI) associated with the reduced number of antenna ports. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199, and / or the transmitting component 2420 or the receiving component 2425 may be configured to send a message to the UE indicating a transmit pre-decoder matrix indicator (TPMI) associated with the reduced number of antenna ports, or may include means for sending a message to the UE indicating a transmit pre-decoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0180] For example, the sending at block 2506 may include: Figure 3 The message is sent via a wireless signal at an antenna or antenna array (e.g., antenna 320) described in.

[0181] In an alternative or additional aspect, the indication is received via a radio resource control (RRC) message.

[0182] In an alternative or additional aspect, the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on the number of antenna ports in the antenna port set.

[0183] In alternative or additional aspects, the indication is sent via a bitmap in a Medium Access Control (MAC) Control Element (CE) message, or wherein the indication is sent via a value in a Downlink Control Information (DCI) message.

[0184] In alternative or additional aspects, each bit in the bitmap corresponds to a resource from a set of resources associated with a reference signal, or wherein the value corresponds to a resource from a set of resources associated with a reference signal.

[0185] refer to Fig.26 In an alternative or additional aspect, at block 2602, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal or wherein the value corresponds to a resource from a set of resources associated with the reference signal, the method 2500 may further include sending to the UE a configuration indicating a set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199, and / or the transmitting component 2420 may be configured to send to the UE a configuration indicating a set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, or may include means for sending to the UE a configuration indicating a set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message.

[0186] For example, the sending at block 2602 may include sending Figure 3 An antenna or antenna array (eg, antenna 320 ) as described in the configuration is used to transmit wireless signals.

[0187] refer to Fig. 27 In an alternative or additional aspect, at block 2702, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal or wherein the value corresponds to a resource from a set of resources associated with the reference signal, the method 2500 may further include sending a second reference signal to the UE along with a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the backoff component 199, and / or the sending component 2420 may be configured to send the second reference signal to the UE along with a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources, or may include means for sending the second reference signal to the UE along with a configuration indicating a set of resources for the reference signal and a number of antenna ports for each resource in the set of resources.

[0188] For example, the sending at block 2702 may include sending Figure 3 The second reference signal and configuration are sent via a wireless signal at the antenna or antenna array (eg, antenna 320) described in .

[0189] In alternative or additional aspects, each bit in the bitmap corresponds to a resource from a plurality of sets of resources associated with a reference signal, or wherein the value corresponds to a resource from a plurality of sets of resources associated with a reference signal.

[0190] refer to Fig.28 , in an alternative or additional aspect, at box 2802, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with a reference signal or wherein the value corresponds to a resource from a plurality of resource sets associated with a reference signal, method 2500 may also include sending a configuration indicating a plurality of resource sets for the reference signal and a corresponding antenna port set for each resource in each resource set from the plurality of resource sets to the UE, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the corresponding resource in the resource set indicated in the bitmap or DCI message. For example, in one aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199 and / or the sending component 2420 may be configured to send a configuration indicating multiple resource sets for reference signals and a corresponding antenna port set for each resource in each resource set from the multiple resource sets to the UE, or may include a component for sending a configuration indicating multiple resource sets for reference signals and a corresponding antenna port set for each resource in each resource set from the multiple resource sets to the UE, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the corresponding resources in the resource set indicated in the bitmap or DCI message.

[0191] For example, the sending at block 2802 may include Figure 3 An antenna or antenna array (eg, antenna 320 ) as described in the configuration is used to transmit wireless signals.

[0192] refer to Fig.29 In an alternative or additional aspect, at block 2902, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with the reference signal or wherein the value corresponds to a resource from a plurality of resource sets associated with the reference signal, the method 2500 may further include sending a second reference signal and a configuration indicating the plurality of resource sets for the reference signal to the UE. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199, and / or the sending component 2420 may be configured to send the second reference signal and a configuration indicating the plurality of resource sets for the reference signal to the UE, or may include means for sending the second reference signal and a configuration indicating the plurality of resource sets for the reference signal to the UE.

[0193] For example, the sending at block 2902 may include: Figure 3The second reference signal is sent via a wireless signal at the antenna or antenna array (eg, antenna 320) described in FIG.

[0194] In an alternative or additional aspect, the reference signal is a sounding reference signal (SRS).

[0195] In an alternative or additional aspect, the value is an SRS Resource Indicator (SRI) value indicated in the DCI message.

[0196] In an alternative or additional aspect, the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

[0197] In an alternative or additional aspect, resources for the reference signal are associated with a number of antenna ports equal to the number of antennas of the apparatus, and wherein the same resources are associated with a reduced number of antenna ports.

[0198] refer to Fig.30 In an alternative or additional aspect, at block 3002, wherein resources of the reference signal are associated with a plurality of antenna ports of the device equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 2500 may further include sending a second reference signal to the UE. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the backoff component 199, and / or the sending component 2420 may be configured to send the second reference signal to the UE, or may include means for sending the second reference signal to the UE.

[0199] For example, the sending at block 3002 may include: Figure 3 The second reference signal is sent via a wireless signal at the antenna or antenna array (eg, antenna 320) described in FIG.

[0200] refer to Fig.31 In an alternative or additional aspect, at block 3102, wherein the resources of the reference signal are associated with a plurality of antenna ports of the device that are equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 2500 may further include sending a set of antenna port identifiers to the UE via a bitmap in a MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199, and / or the sending component 2420 may be configured to send the set of antenna port identifiers to the UE via a bitmap in a MAC CE message, or may include means for sending the set of antenna port identifiers to the UE via a bitmap in a MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers.

[0201] For example, the sending at block 3102 may include Figure 3 The antenna port identifier set is sent via a wireless signal at an antenna or antenna array (eg, antenna 320) described in FIG.

[0202] refer to Fig.32 In an alternative or additional aspect, at block 3202, wherein resources for a reference signal are associated with a plurality of antenna ports of the device that are equal to the number of antennas, and wherein the same resources are associated with a reduced number of antenna ports, the method 2500 may further include sending the set of antenna port identifiers from the network entity via a field or a set of reserved bits in a DCI message. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the fallback component 199, and / or the sending component 2420 may be configured to send the set of antenna port identifiers from the network entity via a field or a set of reserved bits in a DCI message, or may include means for sending the set of antenna port identifiers from the network entity via a field or a set of reserved bits in a DCI message.

[0203] For example, the sending at box 3202 may include Figure 3 The antenna port identifier set is sent via a wireless signal at an antenna or antenna array (eg, antenna 320) described in FIG.

[0204] refer to Fig.33 In an alternative or additional aspect, at block 3302, the method 2500 may further include receiving a capability report from the network entity, the capability report indicating the capability of the UE to increase the transmit power of each antenna port in the reduced number of antenna ports. For example, in an aspect, the network entity 102, the processor 2405, the memory 376, the backoff component 199, and / or the receiving component 2425 may be configured to receive a capability report from the network entity, or may include means for receiving a capability report from the network entity, the capability report indicating the capability of the UE to increase the transmit power of each antenna port in the reduced number of antenna ports.

[0205] For example, the receiving at box 3302 may include Figure 3 Receive the capability report via a wireless signal at an antenna or antenna array (e.g., antenna 320) described in, and process the received wireless signal and capability report as described above.

[0206] In an alternative or additional aspect, the TPMI is associated with a precoding matrix in at least one precoding matrix table, the at least one precoding matrix table including matrices associated with different numbers of antenna ports.

[0207] In an alternative or additional aspect, the precoding matrix is ​​associated with a reduced number of antenna ports.

[0208] Although the foregoing disclosure discusses illustrative aspects and / or embodiments, it should be noted that various changes and modifications may be made herein without departing from the described aspects and / or embodiments as defined by the appended claims. Furthermore, although elements of the described aspects and / or embodiments are described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or part of any aspect and / or embodiment may be used with all or part of any other aspect and / or embodiment unless otherwise stated.

[0209] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is merely an illustration of the exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart may be rearranged based on design preferences. Further, some blocks may be combined or omitted. The attached method claims provide the elements of each block in a sample order, but are not meant to be limited to the specific order or hierarchy provided.

[0210] The foregoing 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 may 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 elements mentioned in the singular are not intended to represent "one and only one", unless specifically so stated, but "one or more". Terms such as "if", "when ......" and "while ......" should be interpreted as "under the condition of ......", rather than meaning an immediate time relationship or reaction. That is, these phrases, such as "when ......", do not mean an immediate action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the conditions are met, then the action will occur, but no specific or immediate time limit is required for the occurrence of the action. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being preferred or having an advantage over 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, which 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 only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout the disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. Words such as "module," "mechanism," "element," "device," etc. cannot replace the word "component." Therefore, no claim element will be construed as a component-plus-function unless the element is explicitly recited using the phrase "component for..."

[0211] The following examples are merely illustrative and may be combined with aspects of other embodiments, implementations, or teachings described herein, but are not limited thereto.

[0212] Embodiment 1 is a method for wireless communication at a user equipment, the method comprising: receiving an indication from a network entity to reduce the number of antenna ports associated with uplink precoding; sending a reference signal to the network entity using the reduced number of antenna ports; and receiving a message from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0213] Embodiment 2 is a method according to embodiment 1, wherein the indication is received via a radio resource control (RRC) message.

[0214] Embodiment 3 is a method according to embodiment 2, wherein the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on the number of antenna ports in the antenna port set.

[0215] Embodiment 4 is a method according to any one of embodiments 1 to 3, wherein the indication is received via a bitmap in a medium access control (MAC) control element (CE) message, or wherein the indication is received via a value in a downlink control information (DCI) message.

[0216] Embodiment 5 is a method according to embodiment 4, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal, or wherein the value corresponds to the resource from the set of resources associated with the reference signal.

[0217] Embodiment 6 is a method according to embodiment 5, the method further comprising: receiving a configuration of the resource set indicating the reference signal and a corresponding antenna port set for each resource in the resource set from the network entity, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the resource indicated in the bitmap or the resource indicated by the value in the DCI message.

[0218] Embodiment 7 is a method according to embodiment 5, wherein the method further includes: receiving a second reference signal from the network entity and a configuration indicating the resource set of the reference signal and the number of antenna ports used for each resource in the resource set; measuring one or more channel metrics for the second reference signal; and mapping the resources indicated in the bitmap or indicated by the value in the DCI message to an antenna port identifier set based on the one or more channel metrics and the number of antenna ports, wherein the reduced number of antenna ports is based on the antenna port identifier set.

[0219] Embodiment 8 is a method according to embodiment 4, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with the reference signal, or wherein the value corresponds to the resource from the plurality of resource sets associated with the reference signal.

[0220] Embodiment 9 is a method according to embodiment 8, and the method further includes: receiving from the network entity a configuration of the multiple resource sets indicating the reference signal and a corresponding antenna port set for each resource in each resource set from the multiple resource sets, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the corresponding resource in the resource set indicated in the bitmap or the DCI message.

[0221] Embodiment 10 is a method according to embodiment 8, wherein the method further includes: receiving a second reference signal and a configuration of the multiple resource sets indicating the reference signal from the network entity; measuring one or more channel metrics for the second reference signal; and mapping the corresponding resources in the resource set indicated in the bitmap or the DCI message to an antenna port identifier set based on the one or more channel metrics and the number of antenna ports, wherein the reduced number of antenna ports is based on the antenna port identifier set.

[0222] Embodiment 11 is a method according to embodiment 5, wherein the reference signal is a sounding reference signal (SRS).

[0223] Embodiment 12 is a method according to embodiment 5, wherein the value is an SRS resource indicator (SRI) value indicated in the DCI message.

[0224] Embodiment 13 is the method of embodiment 5, wherein the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

[0225] Embodiment 14 is a method according to embodiment 4, wherein resources of the reference signal are associated with a number of antenna ports equal to the number of antennas of the device, and wherein the same resources are associated with a reduced number of antenna ports.

[0226] Embodiment 15 is a method according to embodiment 14, the method further comprising: receiving a second reference signal from the network entity; measuring one or more channel metrics for the second reference signal; and mapping the resources to a set of antenna port identifiers based on the one or more channel metrics and the reduced number of antenna ports.

[0227] Embodiment 16 is a method according to embodiment 14, the method further comprising: receiving an antenna port identifier set from the network entity via the bitmap in the MAC CE message, wherein each bit in the bit set in the bitmap corresponds to a corresponding antenna port identifier in the antenna port identifier set.

[0228] Embodiment 17 is a method according to embodiment 14, the method further comprising: receiving a set of antenna port identifiers from the network entity via a field or a set of reserved bits in the DCI message.

[0229] Embodiment 18 is a method according to any one of embodiments 1 to 17, the method further comprising: sending a capability report to the network entity, the capability report indicating the ability of a user equipment (UE) to increase the transmit power of each antenna port among a reduced number of antenna ports.

[0230] Embodiment 19 is a method according to embodiment 18, the method further comprising: increasing the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the increased transmit power.

[0231] Embodiment 20 is a method according to embodiment 18, the method further comprising: suppressing the increase of the transmit power of each antenna port in the reduced number of antenna ports by a threshold power amount, wherein the reference signal is transmitted using the same transmit power per antenna port as that used before reducing the number of antenna ports associated with uplink pre-decoding.

[0232] Embodiment 21 is a method according to any one of embodiments 1 to 20, wherein the TPMI is associated with a precoding matrix in at least one precoding matrix table, wherein the at least one precoding matrix table includes matrices associated with different numbers of antenna ports.

[0233] Embodiment 22 is the method of embodiment 21, wherein the precoding matrix is ​​associated with a reduced number of antenna ports.

[0234] Embodiment 23 is a method for performing wireless communications at a user equipment, the method comprising: sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding; receiving a reference signal from the UE using the reduced number of antenna ports; and sending a message to the UE indicating a transmit predecoder matrix indicator (TPMI) associated with the reduced number of antenna ports.

[0235] Embodiment 24 is a method according to embodiment 23, wherein the indication is sent via a radio resource control (RRC) message.

[0236] Embodiment 25 is a method according to embodiment 24, wherein the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on the number of antenna ports in the antenna port set.

[0237] Embodiment 26 is a method according to any one of embodiments 23 to 25, wherein the indication is sent via a bitmap in a medium access control (MAC) control element (CE) message, or wherein the indication is sent via a value in a downlink control information (DCI) message.

[0238] Embodiment 27 is a method according to embodiment 26, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal, or wherein the value corresponds to the resource from the set of resources associated with the reference signal.

[0239] Embodiment 28 is a method according to embodiment 27, the method further comprising: sending a configuration indicating the resource set for the reference signal and a corresponding antenna port set for each resource in the resource set to the UE, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the resource indicated in the bitmap or indicated by the value in the DCI message.

[0240] Embodiment 29 is a method according to embodiment 27, the method further comprising: sending a second reference signal to the UE and a configuration indicating the resource set of the reference signal and the number of antenna ports used for each resource in the resource set.

[0241] Embodiment 30 is a method according to embodiment 26, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with the reference signal, or wherein the value corresponds to the resource from the plurality of resource sets associated with the reference signal.

[0242] Embodiment 31 is a method according to embodiment 30, and the method further includes: sending to the UE a configuration indicating the multiple resource sets of the reference signal and a corresponding antenna port set for each resource in each resource set from the multiple resource sets, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding antenna port set for the corresponding resources in the resource set indicated in the bitmap or the DCI message.

[0243] Embodiment 32 is a method according to embodiment 30, the method further comprising: sending a second reference signal to the UE and a configuration of the multiple resource sets indicating the reference signal.

[0244] Embodiment 33 is a method according to embodiment 27, wherein the reference signal is a sounding reference signal (SRS).

[0245] Embodiment 34 is a method according to embodiment 27, wherein the value is an SRS resource indicator (SRI) value indicated in the DCI message.

[0246] Embodiment 35 is a method according to embodiment 27, wherein the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

[0247] Embodiment 36 is a method according to embodiment 26, wherein the resources of the reference signal are associated with a number of antenna ports equal to the number of antennas of the device, and wherein the same resources are associated with a reduced number of antenna ports.

[0248] Embodiment 37 is a method according to embodiment 36, wherein the method further includes: sending a second reference signal to the UE.

[0249] Embodiment 38 is a method according to embodiment 36, the method further comprising: sending an antenna port identifier set to the UE via the bitmap in the MAC CE message, wherein each bit in the bit set in the bitmap corresponds to a corresponding antenna port identifier in the antenna port identifier set.

[0250] Embodiment 39 is a method according to embodiment 36, and the method also includes: sending a set of antenna port identifiers from a network entity via a field or a reserved bit set in the DCI message.

[0251] Embodiment 40 is a method according to any one of embodiments 23 to 39, the method further comprising: receiving a capability report from the network entity, the capability report indicating the ability of the UE to increase the transmit power of each antenna port among the reduced number of antenna ports.

[0252] Embodiment 41 is a method according to any one of Embodiments 23 to 40, wherein the TPMI is associated with a precoding matrix in at least one precoding matrix table, wherein the at least one precoding matrix table includes matrices associated with different numbers of antenna ports.

[0253] Embodiment 42 is a method according to embodiment 41, wherein the precoding matrix is ​​associated with a reduced number of antenna ports.

[0254] Embodiment 43 is a device for wireless communication, comprising: a component for executing the method according to any one of Embodiments 1 to 22.

[0255] Embodiment 44 is a device for wireless communication, comprising: a component for executing a method according to any one of Embodiments 23 to 42.

[0256] Embodiment 45 is a non-transitory computer-readable medium, which includes instructions, which when executed by a device cause the device to perform the method according to any one of embodiments 1 to 22.

[0257] Embodiment 46 is a non-transitory computer-readable medium, which includes instructions, which when executed by a device cause the device to perform the method according to any one of embodiments 23 to 42.

[0258] Embodiment 47 is a device for wireless communication, the device comprising: a memory, the memory comprising instructions; and one or more processors, the one or more processors being configured to execute the instructions so that the device performs a method according to any one of Embodiments 1 to 22.

[0259] Embodiment 48 is a device for wireless communication, the device comprising: a memory, the memory comprising instructions; and one or more processors, the one or more processors being configured to execute the instructions so that the device performs a method according to any one of Embodiments 23 to 42.

Claims

1. A device for wireless communication, the device comprising: processor; a memory coupled to the processor; and instructions stored in the memory and which, when executed by the processor, cause the apparatus to: receiving an indication from a network entity to reduce a number of antenna ports associated with uplink precoding; sending a reference signal to the network entity using a reduced number of antenna ports; as well as A message is received from the network entity indicating a transmit precoder matrix indicator (TPMI) associated with a reduced number of antenna ports.

2. The apparatus of claim 1, wherein the indication is received via a radio resource control (RRC) message.

3. The apparatus of claim 2, wherein the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on the number of antenna ports in the antenna port set.

4. The apparatus of claim 1, wherein the indication is received via a bitmap in a medium access control (MAC) control element (CE) message, or wherein the indication is received via a value in a downlink control information (DCI) message.

5. The apparatus of claim 4, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal, or wherein the value corresponds to the resource from the set of resources associated with the reference signal.

6. The apparatus of claim 5, wherein the instructions, when executed by the processor, further cause the apparatus to: Receiving from the network entity a configuration indicating the set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message.

7. The apparatus of claim 5, wherein the instructions, when executed by the processor, further cause the apparatus to: receiving from the network entity a second reference signal and a configuration indicating the set of resources for the reference signal and a number of antenna ports for each resource in the set of resources; measuring one or more channel metrics for the second reference signal; as well as mapping the resources indicated in the bitmap or indicated by the value in the DCI message to a set of antenna port identifiers based on the one or more channel metrics and the number of antenna ports, The reduced number of antenna ports is based on the set of antenna port identifiers.

8. The apparatus of claim 4, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with the reference signal, or wherein the value corresponds to the resource from the plurality of resource sets associated with the reference signal.

9. The apparatus of claim 8, wherein the instructions, when executed by the processor, further cause the apparatus to: receiving, from the network entity, a configuration indicating the plurality of resource sets for the reference signal and a corresponding set of antenna ports for each resource in each resource set from the plurality of resource sets, wherein a reduced number of antenna ports is based on a number of antenna ports in the corresponding set of antenna ports for corresponding resources in the resource sets indicated in the bitmap or the DCI message.

10. The apparatus of claim 8, wherein the instructions, when executed by the processor, further cause the apparatus to: receiving from the network entity a second reference signal and a configuration of the plurality of resource sets indicating the reference signal; measuring one or more channel metrics for the second reference signal; as well as mapping the corresponding resources in the set of resources indicated in the bitmap or the DCI message to a set of antenna port identifiers based on the one or more channel metrics and the number of antenna ports, The reduced number of antenna ports is based on the set of antenna port identifiers. The apparatus of claim 5 , wherein the reference signal is a sounding reference signal (SRS).

12. The apparatus of claim 5, wherein the value is an SRS Resource Indicator (SRI) value indicated in the DCI message.

13. The apparatus of claim 5, wherein the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

14. The apparatus of claim 4, wherein resources of the reference signal are associated with a number of antenna ports equal to the number of antennas of the apparatus, and wherein the same resources are associated with a reduced number of antenna ports.

15. The apparatus of claim 14, wherein the instructions, when executed by the processor, further cause the apparatus to: receiving a second reference signal from the network entity; measuring one or more channel metrics for the second reference signal; and The resources are mapped to a set of antenna port identifiers based on the one or more channel metrics and the reduced number of antenna ports.

16. The apparatus of claim 14, wherein the instructions, when executed by the processor, further cause the apparatus to: A set of antenna port identifiers is received from the network entity via the bitmap in the MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers.

17. The apparatus of claim 14, wherein the instructions, when executed by the processor, further cause the apparatus to: A set of antenna port identifiers is received from the network entity via a field or a set of reserved bits in the DCI message.

18. The apparatus of claim 1, wherein the instructions, when executed by the processor, further cause the apparatus to: A capability report is sent to the network entity, the capability report indicating a capability of a user equipment (UE) to increase transmit power per antenna port of the reduced number of antenna ports.

19. The apparatus of claim 18, wherein the instructions, when executed by the processor, further cause the apparatus to: The transmit power of each antenna port of the reduced number of antenna ports is increased by a threshold power amount, wherein the reference signal is transmitted using the increased transmit power.

20. The apparatus of claim 18, wherein the instructions, when executed by the processor, further cause the apparatus to: The reference signal is transmitted using the same per-antenna port transmit power as was used before the number of antenna ports associated with uplink precoding was reduced.

21. The apparatus of claim 1, wherein the TPMI is associated with a precoding matrix in at least one precoding matrix table, the at least one precoding matrix table comprising matrices associated with different numbers of antenna ports.

22. The apparatus of claim 21, wherein the precoding matrix is ​​associated with a reduced number of antenna ports.

23. An apparatus for wireless communication, the apparatus comprising: processor; a memory coupled to the processor; and instructions stored in the memory and which, when executed by the processor, cause the apparatus to: sending an indication to a user equipment (UE) to reduce the number of antenna ports associated with uplink precoding; receiving a reference signal from the UE using a reduced number of antenna ports; as well as A message is sent to the UE indicating a transmit precoder matrix indicator (TPMI) associated with a reduced number of antenna ports.

24. The apparatus of claim 23, wherein the indication is sent via a radio resource control (RRC) message.

25. The apparatus of claim 24, wherein the indication associates the reference signal with an antenna port set, and the reduced number of antenna ports is based on a number of antenna ports in the antenna port set.

26. The apparatus of claim 23, wherein the indication is sent via a bitmap in a Medium Access Control (MAC) Control Element (CE) message, or wherein the indication is sent via a value in a Downlink Control Information (DCI) message.

27. The apparatus of claim 26, wherein each bit in the bitmap corresponds to a resource from a set of resources associated with the reference signal, or wherein the value corresponds to the resource from the set of resources associated with the reference signal.

28. The apparatus of claim 27, wherein the instructions, when executed by the processor, further cause the apparatus to: and sending a configuration indicating the set of resources for the reference signal and a corresponding set of antenna ports for each resource in the set of resources to the UE, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for the resources indicated in the bitmap or indicated by the value in the DCI message.

29. The apparatus of claim 27, wherein the instructions, when executed by the processor, further cause the apparatus to: A second reference signal is sent to the UE along with a configuration indicating the resource set for the reference signal and a number of antenna ports used for each resource in the resource set.

30. The apparatus of claim 26, wherein each bit in the bitmap corresponds to a resource from a plurality of resource sets associated with the reference signal, or wherein the value corresponds to the resource from the plurality of resource sets associated with the reference signal.

31. The apparatus of claim 30, wherein the instructions, when executed by the processor, further cause the apparatus to: and sending to the UE a configuration indicating the plurality of resource sets for the reference signal and a corresponding set of antenna ports for each resource in each resource set from the plurality of resource sets, wherein the reduced number of antenna ports is based on the number of antenna ports in the corresponding set of antenna ports for corresponding resources in the resource sets indicated in the bitmap or the DCI message.

32. The apparatus of claim 30, wherein the instructions, when executed by the processor, further cause the apparatus to: A second reference signal and a configuration of the multiple resource sets indicating the reference signal are sent to the UE.

33. The apparatus of claim 27, wherein the reference signal is a sounding reference signal (SRS).

34. The apparatus of claim 27, wherein the value is an SRS Resource Indicator (SRI) value indicated in the DCI message.

35. The apparatus of claim 27, wherein the reduced number of antenna ports is mapped to a preconfigured or defined set of port identifiers.

36. The apparatus of claim 26, wherein resources of the reference signal are associated with a number of antenna ports equal to the number of antennas of the apparatus, and wherein the same resources are associated with a reduced number of antenna ports.

37. The apparatus of claim 36, wherein the instructions, when executed by the processor, further cause the apparatus to: A second reference signal is sent to the UE.

38. The apparatus of claim 36, wherein the instructions, when executed by the processor, further cause the apparatus to: A set of antenna port identifiers is sent to the UE via the bitmap in the MAC CE message, wherein each bit in the set of bits in the bitmap corresponds to a respective antenna port identifier in the set of antenna port identifiers.

39. The apparatus of claim 36, wherein the instructions, when executed by the processor, further cause the apparatus to: The set of antenna port identifiers is sent from the network entity via a field or a set of reserved bits in the DCI message.

40. The apparatus of claim 23, wherein the instructions, when executed by the processor, further cause the apparatus to: A capability report is received from the network entity, the capability report indicating a capability of the UE to increase transmit power per antenna port of the reduced number of antenna ports.

41. The apparatus of claim 23, wherein the TPMI is associated with a precoding matrix in at least one precoding matrix table, the at least one precoding matrix table comprising matrices associated with different numbers of antenna ports.

42. The apparatus of claim 41, wherein the precoding matrix is ​​associated with a reduced number of antenna ports.

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