WO2021138884A1

WO2021138884A1 - Signaling design for uplink precoding with restricted uplink transmit power

Info

Publication number: WO2021138884A1
Application number: PCT/CN2020/071301
Authority: WO
Inventors: Liangming WU; Chenxi HAO; Yu Zhang; Min Huang; Chao Wei; Yi Huang
Original assignee: Qualcomm Incorporated
Priority date: 2020-01-10
Filing date: 2020-01-10
Publication date: 2021-07-15

Abstract

A signaling design for uplink precoding with restricted uplink transmit power is disclosed. A user equipment (UE) may have a plurality of transmit antenna ports power limited according to a power amplifier associated with each antenna. The UE determines a maximum transmit power for each of its transmit antenna ports and signals a per transmit antenna power restriction along with its other power class information to a serving base station. The per transmit antennas power restriction is based on the determined maximum transmit power for each antenna. The serving base station may then use the per transmit antenna power restriction to adjust a transmitted precoding matrix indicator (TPMI) for the associated UE to accommodate the per antenna power restriction. The UE can then transmit at an uplink transmit power for the each antenna according to the TPMI.

Description

SIGNALING DESIGN FOR UPLINK PRECODING WITH RESTRICTED UPLINK TRANSMIT POWER

BACKGROUND Field

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to signaling design for uplink precoding with restricted uplink transmit power.

Background

Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the Universal Terrestrial Radio Access Network (UTRAN) . The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS) , a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP) . Examples of multiple-access network formats include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stations or node Bs that can support communication for a number of user equipments (UEs) . A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlink to a UE and/or may receive data and control information on the uplink from the UE. On the downlink, a transmission from the base station may encounter interference due to transmissions from neighbor base stations or from other wireless radio frequency (RF) transmitters. On the uplink, a transmission from the UE may encounter interference from uplink transmissions of other UEs communicating with the neighbor base stations or from other wireless RF transmitters. This interference may degrade performance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance wireless technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

SUMMARY

In one aspect of the disclosure, a method of wireless communication includes determining, by a UE, a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE, signaling, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna, receiving, by the UE, a transmitted precoding matrix indicator (TPMI) from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna, and transmitting, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.

In an additional aspect of the disclosure, a method of wireless communication includes receiving, by a base station, transmit power information associated with one or more served UEs, wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs, adjusting, by the base station, a TPMI for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs, and transmitting, by the base station, the adjusted TPMI to the one or more UEs.

In an additional aspect of the disclosure, an apparatus configured for wireless communication includes means for determining, by a UE, a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE, means for signaling, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna, means for receiving, by the UE, a TPMI from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna, and means for transmitting, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.

In an additional aspect of the disclosure, an apparatus configured for wireless communication includes means for receiving, by a base station, transmit power information associated with one or more served UEs, wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs, means for adjusting, by the base station, a TPMI for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs, and means for transmitting, by the base station, the adjusted TPMI to the one or more UEs.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon. The program code further includes code to determine, by a UE, a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE, code to signal, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna, code to receive, by the UE, a TPMI from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna, and code to transmit, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon. The program code further includes code to receive, by a base station, transmit power information associated with one or more served UEs, wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs, code to adjust, by the base station, a TPMI for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs, and code to transmit, by the base station, the adjusted TPMI to the one or more UEs.

In an additional aspect of the disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes at least one processor, and a memory coupled to the processor. The processor is configured to determine, by a UE, a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE, to signal, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna, to receive, by the UE, a TPMI from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna, and to transmit, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.

In an additional aspect of the disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes at least one processor, and a memory coupled to the processor. The processor is configured to receive, by a base station, transmit power information associated with one or more served UEs, wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs, to adjust, by the base station, a TPMI for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs, and to transmit, by the base station, the adjusted TPMI to the one or more UEs.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purpose of illustration and description, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the present disclosure may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wireless communication system.

FIG. 2 is a block diagram illustrating a design of a base station and a UE configured according to one aspect of the present disclosure.

FIG. 3 is a block diagram illustrating a portion of 5G-NR network in which a UE is configured with multiple transmit antenna ports which may be compatible with a higher resolution TPMI from a serving base station.

FIGs. 4A and 4B are block diagrams illustrating example blocks executed to implement aspects of the present disclosure.

FIG. 5 is a call flow diagram illustrating communications between a base station and UE configured according to aspects of the present disclosure.

FIG. 6. is a call flow diagram illustrating communications between a base station and UE configured according to one aspect of the present disclosure.

FIG. 7 is a block diagram illustrating example blocks executed by a base station to implement one aspect of the present disclosure.

FIG. 8 is a block diagram illustrating a portion of 5G-NR network with a base station and UE configured according to one aspect of the present disclosure.

FIG. 9 is a block diagram illustrating an example UE configured according to aspects of the present disclosure.

FIG. 10 is a block diagram illustrating an example base station configured according to aspects of the present disclosure.

The Appendix provides further details regarding various embodiments of this disclosure and the subject matter therein forms a part of the specification of this application.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the appended drawings and appendix, is intended as a description of various configurations and is not intended to limit the scope of the disclosure. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. It will be apparent to those skilled in the art that these specific details are not required in every case and that, in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

This disclosure relates generally to providing or participating in authorized shared access between two or more wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC- FDMA) networks, LTE networks, GSM networks, 5 ^th Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA) , IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of universal mobile telecommunication system (UMTS) . In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP) , and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . These various radio technologies and standards are known or are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the universal mobile telecommunications system (UMTS) mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-Aare considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with an ultra-high density (e.g., ～1M nodes/km ²) , ultra-low complexity (e.g., ～10s of bits/sec) , ultra-low energy (e.g., ～10+ years of battery life) , and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ～99.9999%reliability) , ultra-low latency (e.g., ～ 1 ms) , and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ～ 10 Tbps/km ²) , extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates) , and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI) ; having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) /frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO) , robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 1, 5, 10, 20 MHz, and the like bandwidth. For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz bandwidth. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with uplink/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.

Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim.

FIG. 1 is a block diagram illustrating an example of a wireless communications system 100 that supports a signaling design for uplink precoding involving restricted uplink transmit power. A UE may have a plurality of transmit antenna ports power limited according to a power amplifier associated with each antenna. The UE determines a maximum transmit power for each of its transmit antenna ports and signals a per transmit antenna power restriction along with its other power class information to a serving base station. The per transmit antennas power restriction is based on the determined maximum transmit power for each antenna. The serving base station may then use the per transmit antenna power restriction to adjust a transmitted precoding matrix indicator (TPMI) for the associated UE to accommodate the per antenna power restriction. The UE can then transmit at an uplink transmit power for the each antenna according to the TPMI n accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or NR network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be referred to as forward link transmissions while uplink transmissions may also be referred to as reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and, therefore, provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone (UE 115a) , a personal digital assistant (PDA) , a wearable device (UE 115d) , a tablet computer, a laptop computer (UE 115g) , or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet-of-things (IoT) device, an Internet-of- everything (IoE) device, an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles (UE 115e and UE 115f) , meters (UE 115b and UE 115c) , or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via machine-to-machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In other cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In certain cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 may facilitate the scheduling of resources for D2D communications. In other cases, D2D communications may be carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one packet data network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP multimedia subsystem (IMS) , or a packet-switched (PS) streaming service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

Wireless communications system 100 may include operations by different network operating entities (e.g., network operators) , in which each network operator may share spectrum. In some instances, a network operating entity may be configured to use an entirety of a designated shared spectrum for at least a period of time before another network operating entity uses the entirety of the designated shared spectrum for a different period of time. Thus, in order to allow network operating entities use of the full designated shared spectrum, and in order to mitigate interfering communications between the different network operating entities, certain resources (e.g., time) may be partitioned and allocated to the different network operating entities for certain types of communication.

For example, a network operating entity may be allocated certain time resources reserved for exclusive communication by the network operating entity using the entirety of the shared spectrum. The network operating entity may also be allocated other time resources where the entity is given priority over other network operating entities to communicate using the shared spectrum. These time resources, prioritized for use by the network operating entity, may be utilized by other network operating entities on an opportunistic basis if the prioritized network operating entity does not utilize the resources. Additional time resources may be allocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resources among different network operating entities may be centrally controlled by a separate entity, autonomously determined by a predefined arbitration scheme, or dynamically determined based on interactions between wireless nodes of the network operators.

In various implementations, wireless communications system 100 may use both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ license assisted access (LAA) , LTE-unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (NR-U) , such as the 5 GHz ISM band. In some cases, UE 115 and base station 105 of the wireless communications system 100 may operate in a shared radio frequency spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEs 115 or base stations 105 may traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UE 115 or base station 105 may perform a listen before talk (LBT) procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available.

A CCA may include an energy detection procedure to determine whether there are any other active transmissions on the shared channel. For example, a device may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include message detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions.

In general, four categories of LBT procedure have been suggested for sensing a shared channel for signals that may indicate the channel is already occupied. In a first category (CAT 1 LBT) , no LBT or CCA is applied to detect occupancy of the shared channel. A second category (CAT 2 LBT) , which may also be referred to as an abbreviated LBT, a single-shot LBT, or a 25-μs LBT, provides for the node to perform a CCA to detect energy above a predetermined threshold or detect a message or preamble occupying the shared channel. The CAT 2 LBT performs the CCA without using a random back-off operation, which results in its abbreviated length, relative to the next categories.

A third category (CAT 3 LBT) performs CCA to detect energy or messages on a shared channel, but also uses a random back-off and fixed contention window. Therefore, when the node initiates the CAT 3 LBT, it performs a first CCA to detect occupancy of the shared channel. If the shared channel is idle for the duration of the first CCA, the node may proceed to transmit. However, if the first CCA detects a signal occupying the shared channel, the node selects a random back-off based on the fixed contention window size and performs an extended CCA. If the shared channel is detected to be idle during the extended CCA and the random number has been decremented to 0, then the node may begin transmission on the shared channel. Otherwise, the node decrements the random number and performs another extended CCA. The node would continue performing extended CCA until the random number reaches 0. If the random number reaches 0 without any of the extended CCAs detecting channel occupancy, the node may then transmit on the shared channel. If at any of the extended CCA, the node detects channel occupancy, the node may re-select a new random back-off based on the fixed contention window size to begin the countdown again.

A fourth category (CAT 4 LBT) , which may also be referred to as a full LBT procedure, performs the CCA with energy or message detection using a random back-off and variable contention window size. The sequence of CCA detection proceeds similarly to the process of the CAT 3 LBT, except that the contention window size is variable for the CAT 4 LBT procedure.

Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum may result in communication inefficiencies. This may be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access a shared resource. In wireless communications system 100, base stations 105 and UEs 115 may be operated by the same or different network operating entities. In some examples, an individual base station 105 or UE 115 may be operated by more than one network operating entity. In other examples, each base station 105 and UE 115 may be operated by a single network operating entity. Requiring each base station 105 and UE 115 of different network operating entities to contend for shared resources may result in increased signaling overhead and communication latency.

In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) . The single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .

In certain implementations, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In additional cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot, while in other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier, ” as may be used herein, refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In certain instances, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum, such as NR-shared spectrum (NR-SS) ) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In additional cases, an eCC may utilize a different symbol duration than other component carriers, which may include use of a reduced symbol duration as compared with symbol durations of the other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc. ) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE 115, which may be one of the base station and one of the UEs in FIG. 1. At base station 105, a transmit processor 220 may receive data from a data source 212 and control information from a controller/processor 240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a through 232t may be transmitted via the antennas 234a through 234t, respectively.

At UE 115, the antennas 252a through 252r may receive the downlink signals from the base station 105 and may provide received signals to the demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all the demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 115 to a data sink 260, and provide decoded control information to a controller/processor 280.

On the uplink, at the UE 115, a transmit processor 264 may receive and process data (e.g., for the PUSCH) from a data source 262 and control information (e.g., for the PUCCH) from the controller/processor 280. The transmit processor 264 may also generate reference symbols for a reference signal. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by the modulators 254a through 254r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 105. At the base station 105, the uplink signals from the UE 115 may be received by the antennas 234, processed by the demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 115. The processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller/processor 240.

The controllers/

processors

240 and 280 may direct the operation at the base station 105 and the UE 115, respectively. The controller/processor 240 and/or other processors and modules at the base station 105 may perform or direct the execution of various processes for the techniques described herein. The controllers/processor 280 and/or other processors and modules at the UE 115 may also perform or direct the execution of the functional blocks illustrated in FIGs. 4A and 4B, and/or other processes for the techniques described herein. The

memories

242 and 282 may store data and program codes for the base station 105 and the UE 115, respectively. A scheduler 244 may schedule UEs for data transmission on the downlink and/or uplink.

Uplink transmission precoding has been supported since the implementation of LTE radio access technologies. 5G-NR has leveraged the same precoding codebooks from LTE, which support a rank of up to 4 with wideband precoding. To further improve the uplink performance in 5G-NR operations, use of a higher resolution transmitted precoding matrix indicator (TPMI) may be beneficial. The “higher resolution” of the TPMI refers to the amplitude and/or phase adjustment on the transmit precoder. For example, instead of a fixed transmit power per transmit antenna, more levels of transmit power per transmit antenna may be introduced, such as to mimic eigen beamforming. Compared with the existing non-codebook based approach, no UE transmit or receive antenna calibration would be required, while there would further be no reciprocity mismatch (frequency division duplex (FDD) /time division duplex (TDD) ) impact.

FIG. 3 is a block diagram illustrating a portion of 5G-NR network 30 in which UE 115a is configured with multiple transmit antenna ports which may be compatible with a higher resolution TPMI from base station 105. When a per transmit antenna amplitude adjustment is configured in TPMI, there is a possibility that UE 115a may not be capable of fulfilling the transmit antenna power adjustment as signaled by the TPMI from base station 105. Each transmit antenna of UE 115a is connected to a power amplifier with limited transmit power. When the signaled per transmit antenna power in the TPMI from base station 105 for the corresponding transmit antenna exceeds the maximum transmit power, as illustrated in FIG. 3, the target transmission power cannot be applied by UE 115a. For example, UE 115a may be configured for a particular target transmit power, as illustrated in configured target power line 300. UE 115a includes two transmit antenna ports (Tx1 and Tx2) each restricted by a maximum transmit power, as illustrated in max power line (e.g., Tx1 max power + Tx2 max power) . The difference between the combined maximum power of the two transmit antenna ports of UE 115a and the target transmit power is identified as the power headroom, as illustrated in configured target power line 300.

Upon receipt of a higher resolution TPMI from base station 105 that includes a per transmit antenna power allocation, UE 115a may not be able to implement the configured power allocation. As illustrated in estimated power line 301, if UE 115a were to apply the configured transmit powers for Tx1 and Tx2, the configured power allocation for Tx1 would exceed the maximum transmit power of Tx1. Accordingly, UE 115a would not transmit on Tx1 according to the configured transmit power even though the combined configured power for Tx1 and Tx2 would still not exceed the target transmit power.

FIG. 4A is a block diagram illustrating example blocks executed by a UE to implement one aspect of the present disclosure. The example blocks will also be described with respect to UE 115 as illustrated in FIGs. 2 and 9. FIG. 9 is a block diagram illustrating UE 115 configured according to one aspect of the present disclosure. UE 115 includes the structure, hardware, and components as illustrated for UE 115 of FIG. 2. For example, UE 115 includes controller/processor 280, which operates to execute logic or computer instructions stored in memory 282, as well as controlling the components of UE 115 that provide the features and functionality of UE 115. UE 115, under control of controller/processor 280, transmits and receives signals via wireless radios 900a-r and antennas 252a-r. Wireless radios 900a-r includes various components and hardware, as illustrated in FIG. 2 for UE 115, including modulator/demodulators 254a-r, MIMO detector 256, receive processor 258, transmit processor 264, and TX MIMO processor 266.

At block 400, an example UE configured according to the illustrated aspect determines a maximum transmit power for each transmit antenna configured for the UE. Each of antennas 252a-r may be coupled to a corresponding power amplifier, such as power amplifiers 901a-r, for transmission. The capabilities or configuration of power amplifiers 901a-r will establish a maximum transmit power for each of antennas 252a-r. In implementing the features and functionality of the present disclosure, UE 115a includes transmit power restriction logic 902, stored in memory 282. Under control of controller/processor 280, UE 115a executes transmit power restriction logic 902. The executed instructions and functionality produced according to the executing instructions (referred to as “the execution environment” ) provides the actions taken by UE 115a to implement the various aspects of the present disclosure. As such, within the execution environment of transmit power restriction logic 902, UE 115a determines the maximum transmit power for each transmit antenna, as indicated by the capabilities and limits of power amplifiers 901a-r. This maximum per antenna transmit power information may be stored in memory 282 at transmit antenna power 903.

At block 401, the UE may then signal a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna. Within the execution environment of transmit power restriction logic 902, UE 115a determines a per antenna transmit power restriction and signals this restriction to its serving base station via wireless radios 900a-r, power amplifiers 901a-r, and antennas 252a-r. The per transmit power restriction may include the maximum transmit power for each of the antennas, which as noted above, may be stored at transmit antenna power 902 in memory 282. Thus, the per antenna transmit power restriction signaled by UE 115a would include the maximum transmit power for each of antennas 252a-r. The per transmit power restriction may also include a maximum TPMI restriction amplitude. As noted in greater detail below, the maximum TPMI restriction amplitude provides a constant or amplitude multiplier that the serving base station would use to modify the configured TPMI for UE 115a. This maximum restriction amplitude would be determined by UE 115a, within the execution environment of transmit power restriction logic 902, using the per antenna maximum transmit power. Additionally, the per transmit power restriction signaled by UE 115a may be embedded in a specially selected MCS value that is known by the base station to indicate the maximum transmit power or power restriction of the TPMI.

At block 402, the UE may then receive a TPMI from a serving base station, wherein the TPMI either accounts for or does not account for the maximum transmit power for the each transmit antenna. UE 115a may receive uplink transmission control information from its serving base station that includes a TPMI with per antenna transmit power configurations. This TPMI may have been signaled by the serving base station without accounting for the per transmit antenna power restriction or it may account for such power restriction of UE 115a. UE 115a receives such TPMI from the serving base station via antennas 252a-r and wireless radios 900a-r.

At block 403, the UE would then transmit uplink data at an uplink transmit power for each transmit antenna using the TPMI. Upon receiving the TPMI from the serving base station, UE 115a, under control of controller/processor 280, executes transmission power management logic 905. The execution environment of transmission power management logic 905 provides UE 115a with the functionality to manage the transmit power for its uplink transmissions based on both power configuration information received from its serving base station and additional conditions and measurements observed by UE 115a. Within the execution environment of transmission power management logic 905, UE 115a would configure the transmission of uplink data using the TPMI information. This configuration would include configuring the transmit power for each of its configured transmit antenna ports according to the per antenna power configuration included in the TPMI information. If the TPMI accounts for the per antenna restriction of UE 115a, UE 115a may transmit the uplink data at the configured per antenna transmit power without exceeding the maximum power limitations of any of the transmit antenna ports. Otherwise, if the TPMI does not account for per antenna power restriction, UE 115a may select a new MCS, such as a lower MCS, when the power configuration information of the TPMI would cause UE 115a to exceed the maximum transmit power for any of the configured transmit antenna ports.

FIG. 4B is a block diagram illustrating example blocks executed by a base station to implement one aspect of the present disclosure. The example blocks will also be described with respect to base station 105 as illustrated in FIGs. 2 and 10. FIG. 10 is a block diagram illustrating base station 105 configured according to one aspect of the present disclosure. Base station 105 includes the structure, hardware, and components as illustrated for base station 105 of FIG. 2. For example, base station 105 includes controller/processor 240, which operates to execute logic or computer instructions stored in memory 242, as well as controlling the components of base station 105 that provide the features and functionality of base station 105. Base station 105, under control of controller/processor 240, transmits and receives signals via wireless radios 1000a-t and antennas 234a-t. Wireless radios 1000a-t includes various components and hardware, as illustrated in FIG. 2 for base station 105, including modulator/demodulators 232a-t, MIMO detector 236, receive processor 238, transmit processor 220, and TX MIMO processor 230.

At block 410, an example base station configured according to the illustrated aspect receives transmit power information associated with one or more served UEs. In implementing the features and functionality of the present disclosure, base station 105 includes UE transmit power restriction logic 1001, stored in memory 242. Under control of controller/processor 240, base station 105 executes UE transmit power restriction logic 1001. Within the execution environment of UE transmit power restriction logic 1001, base station 105 is provided with the functionality to determine signaling from served UEs that provides information to determine whether base station 105 will configure per antenna transmit power not merely based on UE power class and power headroom information, but also based on any restrictions identified by the UE based on limitations on the maximum power for each of the UE’s configured transmit antenna ports. Base station 105 receives signaling including transmit power information from one or more served UEs via antennas 234a-t and wireless radios 1000a-t. The transmit power information may include at least a per transmit antenna power restriction based on the maximum transmit power for each transmit antenna of the UE. The signaled information may also include UE power class information and UE power headroom.

At block 411, the base station may then adjust the TPMI for each of the UEs to accommodate the per transmit antenna power restriction received from the corresponding UE. Within the execution environment of UE transmit power restriction logic 1001, base station 105 uses the per transmit antenna power restriction from the transmit power information with TPMI generator 1002, stored in memory 242 and executed under control of controller/processor 240, to adjust a TPMI to account for the per antenna power restrictions indicated by the UE.

At block 412, the base station then transmits the adjusted TPMI to the one or more UEs. Base station 105 may then signal the adjusted TPMI through transmissions via wireless radios 1000 and antennas 234a-t.

It should be noted that, in the example aspect in which the per antenna power restriction signaled by UE 115a includes selection of an MCS value from a set of MCS values configured by the serving base station, base station 105, base station 105 would initially generate the set of MCS value through execution, under control of controller/processor 240, of MCS set generator 1003, stored in memory 242. Within the execution environment of MCS set generator 1003, base station 105 would generate a set of MCS values that correspond to different maximum per antenna transmit powers, such that when base station 105 recognizes the MCS selected by UE 115a for transmission, base station 105 may determine any per antenna transmit power restriction to which UE 115a is subject.

FIG. 5 is a call flow diagram illustrating communications between base station 105 and UE 115a, each configured according to aspects of the present disclosure. At 500, UE 115a determines a per transmit antenna maximum power for each of its configured transmit antenna ports. The maximum transmit power for each such antenna will be determined according to the rating or capabilities of the power amplifier coupled to each antenna. UE 115a may then signal a per antenna power restriction to base station 105 at 501. In a first example aspect of the present disclosure, the per antenna power restriction signaled by UE 115a may include the maximum transmit power per configured transmit antenna. This per transmit antenna maximum transmit power may be signaled in addition to the UE 115a’s power class and headroom information. For purposes of example only, a given UE, such as UE 115a, configured with four power-limited transmit antenna ports, may transmit the per antenna maximum transmit power of 23dBm, 23dBm, 20dBm, and 20dBm. It should be noted that the specific numbers for the maximum transmit power are for illustration purposes only and other implementations may have different maximum transmit power levels. At 502, base station 105 may use the power class and power headroom information together with per transmit antenna power limitation to determine an adjusted TPMI. For example, where the power class indicates a maximum power of 26dBm, and the power head room indicates a 3dB window from the maximum power, the concurrent transmit antenna power would be 23dBm. Base station 105 transmits the adjusted TPMI to UE 115a at 503. Base station 105 may, thus, guarantee, through the adjusted, higher resolution TPMI, that all configured transmit antenna ports of UE 115a will transmit with a power below the maximum per transmit antenna power. However, if UE 115a, instead, receives a TPMI that does not account for the maximum per transmit antenna power, UE 115a would not be required to transmit using the configured uplink modulation and coding scheme (MCS) , if such TPMI configures the transmit power beyond UE 115a’s capabilities.

In a second example aspect of the present disclosure illustrated in FIG. 5, the per antenna power restriction signaled by UE 115a at 501 may include a maximum TPMI restriction amplitude to base station 105. A maximum TPMI restriction amplitude may include values such as 0dB, -3dB, -3dB, -6dB, and the like. The maximum restriction may be signaled at 501 by UE 115a via RRC signaling. Base station 105, at 502, may adjust the amplitude of the TMPI using a selected value, upon receiving the maximum restriction amplitude from UE 115a would restrict base station 105 from adjusting the TPMI with an amplitude larger than the maximum restricted value from UE 115a.

It should be noted that, in an additional aspect, the functionality for base station 105 to restrict on adjust the TPMI may be activated or deactivated via a trigger signal, TPMI restriction activation signal, from UE 115a. For example, UE 115a may signal the TPMI restriction activation signal or deactivation signal (e.g., via MAC-CE signaling) , at 505, after UE 115a detects the transmit antenna power is constrained by a certain power amplifier and pre-defined rules, such as at 500. Thus, in implementation, the UE TPMI restriction may be activated when UE 115a detects the power headroom is close to or less than 0-dB.

FIG. 6 is a call flow diagram illustrating communications between base station 105 and UE 115a, each configured according to one aspect of the present disclosure. In a third example aspect of the present disclosure, base station 105 configures a set of MCS values at 600 in which each MCS value in the set may correspond to a particular transmit power antenna capability. Base station 105 signals the set of MCS values and a TPMI configured for UE 115a at 601 to UE 115a. At 602, UE 115a may then select a particular MCS value based on UE 115a’s per transmit antenna power capability and configured TPMI. If the configured TPMI cannot be used because of a limited transmit antenna power, UE 115a may then select a lower MCS value of the set. UE 115a transmits uplink data at 603 using the selected MCS value. Base station 105 may then detect the MCS value used and, at 604, adjust future TPMI accordingly. Base station 105 would transmit the adjusted TPMI at 605, which UE 115a would use for future transmissions of uplink data, such as at 606. Base station 105 may detect which MCS is used with the received uplink transmission at 603 either through blind detection based on the configured set of MCS values or UE 115a may embed the selected MCS information in other signaling.

It should be noted that, in additional aspects, instead of configured a set of different MCS values, base station 105 may configured a set of offset values, transmitted at 601 with the configured TPMI. UE 115a would then selected the particular offset to adjust the configured MCS to the more suitable MCS level.

FIG. 7 is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The example blocks will also be described with respect to UE 115 as illustrated in FIGs. 2 and 9.

At block 700, a UE receives a TPMI and a set of MCS values configured to accommodate various per transmit antenna power restrictions. A UE, such as UE 115a, may receive a configured TPMI along with a set of MCS value from a serving base station via antennas 252a-r and wireless radios 900a-r. UE 115a stores the set of MCS values in memory 282 at MCS values 904. Each MCS value of the set may correspond to a per antenna maximum transmit power, such that, by selecting a particular MCS value, UE 115a implicitly signals a per antenna power restriction to the serving base station.

At block 701, a determination is made whether the UE may implement the transmit power identified in the TPMI according to the configured MCS value without any power limitations. When preparing for uplink transmission using the configuration information, including the received TPMI, from the serving base station, UE 115a, within the execution environment of transmit power restriction logic 902 and transmit power management 905, may determine whether the configured per antenna transmit power may be used to transmit the uplink data using the configured MCS value. If so, then in block 702, the UE may transmit the data at the identified transmit power using a selected higher MCS value. If no maximum transmit power limit is exceeded considering the power configuration of the TPMI and the configured MCS, UE 115a may select a higher MCS value from MCS values 904 and proceed to transmit uplink data via wireless radios 900a-r, power amplifiers 90a-r, and antennas 252a-r.

If the power identified by the TPMI will result in the UE exceeding the maximum transmit power of a configured transmit antenna, then, at block 703, the UE selects a lower MCS value and transmits at the lower MCS value. If UE, instead, determines that the power configuration of the configured TPMI and MCS value would exceed the maximum transmit power of any of its configured transmit antenna ports, then, within the execution environment of transmit power restriction logic 902, UE 115a would be allowed to select a lower MCS value from MCS values 904 and proceed to transmit uplink data via wireless radios 900a-r, power amplifiers 90a-r, and antennas 252a-r, at the modified transmission configuration. The base station may then detect the lower MCS value and adjust future TPMI to UE 115a.

FIG. 8 is a block diagram illustrating a portion of 5G-NR network 80 with base station 105 and UE 115a configured according to one aspect of the present disclosure. In one example implementation, the base station, such as base station 105, may determine the selected MCS value by identifying a phase shift in a reference signal from UE 115a. For example, UE 115a may shift the phase of such certain reference signals (e.g., demodulation reference signals (DMRS) ) by a selected phase offset. The value of the selected phase offset indicates the selected MCS value to base station 105. Thus, within first transmission 800 using the higher MCS value, UE 115a transmits DMRS symbol 2 as DMRS symbol 1 at a first phase offset (e.g., phase 1) . The selected phase offset of phase 1 identifies the higher MCS value of first transmission 800 to base station 105. Similarly, in second transmission 801 at the lower MCS value, UE 115a transmits DMRS symbol 2 as DMRS symbol 1 at a second phase offset (e.g., phase 2) . The selected phase offset of phase 2 identifies the lower MCS value of second transmission 801 to base station 105. Accordingly, base station 105 would be able to determine which MCS value is selected by UE 115a by identifying the selected phase offset (e.g., phase 1 vs. phase 2) of the transmitted reference signal.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The functional blocks and modules in FIGs. 4A and 4B may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Skilled artisans will also readily recognize that the order or combination of components, methods, or interactions that are described herein are merely examples and that the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Computer-readable storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, a connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL) , then the coaxial cable, fiber optic cable, twisted pair, or DSL, are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

As used herein, including in the claims, the term “and/or, ” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any of these in any combination thereof.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

WHAT IS CLAIMED IS:

Claims

A method of wireless communication, comprising:

determining, by a user equipment (UE) , a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE;

signaling, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna;

receiving, by the UE, a transmitted precoding matrix indicator (TPMI) from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna; and

transmitting, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.
The method of claim 1, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The method of claim 1, further including:

determining, by the UE, that the TPMI identifies the uplink transmit power exceeding the maximum transmit power for at least one transmit antenna ports of the plurality of transmit antenna ports, wherein the transmitting includes transmitting the uplink data using a different modulation and coding scheme (MCS) from an MCS configured by the serving base station for the transmitting.
The method of claim 1, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the UE would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of a configured TPMI.
The method of claim 4, further including:

determining, by the UE, at least one antenna of the plurality of transmit antenna ports is power constrained by an associated power amplifier; and

signaling, by the UE, a TPMI restriction activation signal to the serving base station, wherein the TPMI restriction activation signal is configured to trigger TPMI restriction by the serving base station according to the TPMI restriction amplitude.
The method of claim 1, further including:

receiving, by the UE, a set of modulation and coding scheme (MCS) values from the serving base station, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the UE from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The method of claim 6, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The method of claim 6, further including:

determining, by the UE, that the TPMI does not account for the maximum transmit power;

selecting, by the UE, a new MCS value from the set of MCS values, wherein the new MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the transmitting includes transmitting the uplink data according to the new MCS value.
The method of claim 6, further including:

selecting, by the UE, an MCS value from the set of MCS values, wherein the MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the transmitting includes transmitting the uplink data according to the MCS value; and

shifting, by the UE, a phase by a selected phase offset of a reference signal transmitted to the serving base station, wherein a value of the selected phase offset indicates the MCS value selected to the serving base station.
The method of any combination of claims 1-9.
A method of wireless communication, comprising:

receiving, by a base station, transmit power information associated with one or more served user equipments (UEs) , wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs;

adjusting, by the base station, a transmitted precoding matrix indicator (TPMI) for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs; and

transmitting, by the base station, the adjusted TPMI to the one or more UEs.
The method of claim 11, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The method of claim 11, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the one or more UEs would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of the adjusted TPMI.
The method of claim 13, further including:

receiving, by the base station, a TPMI restriction activation signal from the one or more UEs; and

activating, by the base station, TPMI restriction according to the TPMI restriction amplitude in response to the TPMI restriction activation.
The method of claim 11, further including:

signaling, by the base station, a set of modulation and coding scheme (MCS) values to the one or more UEs, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the one or more UEs from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The method of claim 15, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The method of claim 15, further including:

receiving, by the base station, uplink transmission from the one or more UEs;

determining, by the base station, the MCS value of the set of MCS values associated with the uplink transmission; and

determining, by the base station, the per transmit antenna power restriction corresponding to the MCS value.
The method of claim 17, wherein the determining the MCS value includes one of:

performing blind detection on the uplink transmission based on the set of MCS values; or

identifying a phase offset of a reference signal received from the one or more UEs, wherein a value of the phase offset indicates the MCS value.
The method of any combination of claims 11-18.
An apparatus configured for wireless communication, comprising:

means for determining, by a user equipment (UE) , a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE;

means for signaling, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna;

means for receiving, by the UE, a transmitted precoding matrix indicator (TPMI) from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna; and

means for transmitting, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.
The apparatus of claim 20, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The apparatus of claim 20, further including:

means for determining, by the UE, that the TPMI identifies the uplink transmit power exceeding the maximum transmit power for at least one transmit antenna ports of the plurality of transmit antenna ports, wherein the means for transmitting includes means for transmitting the uplink data using a different modulation and coding scheme (MCS) from an MCS configured by the serving base station for the means for transmitting.
The apparatus of claim 20, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the UE would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of a configured TPMI.
The apparatus of claim 23, further including:

means for determining, by the UE, at least one antenna of the plurality of transmit antenna ports is power constrained by an associated power amplifier; and

means for signaling, by the UE, a TPMI restriction activation signal to the serving base station, wherein the TPMI restriction activation signal is configured to trigger TPMI restriction by the serving base station according to the TPMI restriction amplitude.
The apparatus of claim 20, further including:

means for receiving, by the UE, a set of modulation and coding scheme (MCS) values from the serving base station, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the UE from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The apparatus of claim 25, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The apparatus of claim 25, further including:

means for determining, by the UE, that the TPMI does not account for the maximum transmit power;

means for selecting, by the UE, a new MCS value from the set of MCS values, wherein the new MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the means for transmitting includes means for transmitting the uplink data according to the new MCS value.
The apparatus of claim 25, further including:

means for selecting, by the UE, an MCS value from the set of MCS values, wherein the MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the means for transmitting includes means for transmitting the uplink data according to the MCS value; and

means for shifting, by the UE, a phase by a selected phase offset of a reference signal transmitted to the serving base station, wherein a value of the selected phase offset indicates the MCS value selected to the serving base station.
The apparatus of any combination of claims 20-28.
An apparatus configured for wireless communication, comprising:

means for receiving, by a base station, transmit power information associated with one or more served user equipments (UEs) , wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs;

means for adjusting, by the base station, a transmitted precoding matrix indicator (TPMI) for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs; and

means for transmitting, by the base station, the adjusted TPMI to the one or more UEs.
The apparatus of claim 30, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The apparatus of claim 30, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the one or more UEs would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of the adjusted TPMI.
The apparatus of claim 32, further including:

means for receiving, by the base station, a TPMI restriction activation signal from the one or more UEs; and

means for activating, by the base station, TPMI restriction according to the TPMI restriction amplitude in response to the TPMI restriction activation.
The apparatus of claim 30, further including:

means for signaling, by the base station, a set of modulation and coding scheme (MCS) values to the one or more UEs, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the one or more UEs from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The apparatus of claim 34, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The apparatus of claim 34, further including:

means for receiving, by the base station, uplink transmission from the one or more UEs;

means for determining, by the base station, the MCS value of the set of MCS values associated with the uplink transmission; and

means for determining, by the base station, the per transmit antenna power restriction corresponding to the MCS value.
The apparatus of claim 36, wherein the means for determining the MCS value includes one of:

means for performing blind detection on the uplink transmission based on the set of MCS values; or

means for identifying a phase offset of a reference signal received from the one or more UEs, wherein a value of the phase offset indicates the MCS value.
The apparatus of any combination of claims 30-37.
A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

program code executable by a computer for causing the computer to determine, by a user equipment (UE) , a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE;

program code executable by the computer for causing the computer to signal, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna;

program code executable by the computer for causing the computer to receive, by the UE, a transmitted precoding matrix indicator (TPMI) from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna; and

program code executable by the computer for causing the computer to transmit, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.
The non-transitory computer-readable medium of claim 39, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The non-transitory computer-readable medium of claim 39, further including:

program code executable by the computer for causing the computer to determine, by the UE, that the TPMI identifies the uplink transmit power exceeding the maximum transmit power for at least one transmit antenna ports of the plurality of transmit antenna ports, wherein the program code executable by the computer for causing the computer to transmit includes program code executable by the computer for causing the computer to transmit the uplink data using a different modulation and coding scheme (MCS) from an MCS configured by the serving base station for the program code executable by the computer for causing the computer to transmit.
The non-transitory computer-readable medium of claim 39, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the UE would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of a configured TPMI.
The non-transitory computer-readable medium of claim 42, further including:

program code executable by the computer for causing the computer to determine, by the UE, at least one antenna of the plurality of transmit antenna ports is power constrained by an associated power amplifier; and

program code executable by the computer for causing the computer to signal, by the UE, a TPMI restriction activation signal to the serving base station, wherein the TPMI restriction activation signal is configured to trigger TPMI restriction by the serving base station according to the TPMI restriction amplitude.
The non-transitory computer-readable medium of claim 39, further including:

program code executable by the computer for causing the computer to receive, by the UE, a set of modulation and coding scheme (MCS) values from the serving base station, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the UE from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The non-transitory computer-readable medium of claim 44, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The non-transitory computer-readable medium of claim 44, further including:

program code executable by the computer for causing the computer to determine, by the UE, that the TPMI does not account for the maximum transmit power;

program code executable by the computer for causing the computer to select, by the UE, a new MCS value from the set of MCS values, wherein the new MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the program code executable by the computer for causing the computer to transmit includes program code executable by the computer for causing the computer to transmit the uplink data according to the new MCS value.
The non-transitory computer-readable medium of claim 44, further including:

program code executable by the computer for causing the computer to select, by the UE, an MCS value from the set of MCS values, wherein the MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the program code executable by the computer for causing the computer to transmit includes program code executable by the computer for causing the computer to transmit the uplink data according to the MCS value; and

program code executable by the computer for causing the computer to shift, by the UE, a phase by a selected phase offset of a reference signal transmitted to the serving base station, wherein a value of the selected phase offset indicates the MCS value selected to the serving base station.
The non-transitory computer-readable medium of any combination of claims 30-47.
A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

program code executable by a computer for causing the computer to receive, by a base station, transmit power information associated with one or more served user equipments (UEs) , wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs;

program code executable by the computer for causing the computer to adjust, by the base station, a transmitted precoding matrix indicator (TPMI) for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs; and

program code executable by the computer for causing the computer to transmit, by the base station, the adjusted TPMI to the one or more UEs.
The non-transitory computer-readable medium of claim 49, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The non-transitory computer-readable medium of claim 49, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the one or more UEs would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of the adjusted TPMI.
The non-transitory computer-readable medium of claim 51, further including:

program code executable by the computer for causing the computer to receive, by the base station, a TPMI restriction activation signal from the one or more UEs; and

program code executable by the computer for causing the computer to activate, by the base station, TPMI restriction according to the TPMI restriction amplitude in response to the TPMI restriction activation.
The non-transitory computer-readable medium of claim 49, further including:

program code executable by the computer for causing the computer to signal, by the base station, a set of modulation and coding scheme (MCS) values to the one or more UEs, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the one or more UEs from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The non-transitory computer-readable medium of claim 53, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The non-transitory computer-readable medium of claim 53, further including:

program code executable by the computer for causing the computer to receive, by the base station, uplink transmission from the one or more UEs;

program code executable by the computer for causing the computer to determine, by the base station, the MCS value of the set of MCS values associated with the uplink transmission; and

program code executable by the computer for causing the computer to determine, by the base station, the per transmit antenna power restriction corresponding to the MCS value.
The non-transitory computer-readable medium of claim 55, wherein the program code executable by the computer for causing the computer to determine the MCS value includes one of:

program code executable by the computer for causing the computer to perform blind detection on the uplink transmission based on the set of MCS values; or

program code executable by the computer for causing the computer to identify a phase offset of a reference signal received from the one or more UEs, wherein a value of the phase offset indicates the MCS value.
The non-transitory computer-readable medium of any combination of claims 49-56.
An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured:

to determine, by a user equipment (UE) , a maximum transmit power for each transmit antenna of a plurality of transmit antenna ports configured for the UE;

to signal, by the UE, a per transmit antenna power restriction along with UE power class information to a serving base station, wherein the per transmit antennas power restriction is based on the determined maximum transmit power for the each transmit antenna;

to receive, by the UE, a transmitted precoding matrix indicator (TPMI) from the serving base station, wherein the TPMI one of: accounts for or does not account for the maximum transmit power for the each transmit antenna; and

to transmit, by the UE, uplink data at an uplink transmit power for the each transmit antenna using the TPMI.
The apparatus of claim 58, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The apparatus of claim 58, further including configuration of the at least one processor:

to determine, by the UE, that the TPMI identifies the uplink transmit power exceeding the maximum transmit power for at least one transmit antenna ports of the plurality of transmit antenna ports, wherein the configuration of the at least one processor to transmit includes configuration of the at least one processor to transmit the uplink data using a different modulation and coding scheme (MCS) from an MCS configured by the serving base station for the configuration of the at least one processor to transmit.
The apparatus of claim 58, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the UE would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of a configured TPMI.
The apparatus of claim 61, further including configuration of the at least one processor:

to determine, by the UE, at least one antenna of the plurality of transmit antenna ports is power constrained by an associated power amplifier; and

to signal, by the UE, a TPMI restriction activation signal to the serving base station, wherein the TPMI restriction activation signal is configured to trigger TPMI restriction by the serving base station according to the TPMI restriction amplitude.
The apparatus of claim 58, further including configuration of the at least one processor:

to receive, by the UE, a set of modulation and coding scheme (MCS) values from the serving base station, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the UE from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The apparatus of claim 63, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The apparatus of claim 63, further including configuration of the at least one processor:

to determine, by the UE, that the TPMI does not account for the maximum transmit power;

to select, by the UE, a new MCS value from the set of MCS values, wherein the new MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the configuration of the at least one processor to transmit includes configuration of the at least one processor to transmit the uplink data according to the new MCS value.
The apparatus of claim 63, further including configuration of the at least one processor:

to select, by the UE, an MCS value from the set of MCS values, wherein the MCS value corresponds to the power limitation reflected by the maximum transmit power of the each transmit antenna, wherein the configuration of the at least one processor to transmit includes configuration of the at least one processor to transmit the uplink data according to the MCS value; and

to shift, by the UE, a phase by a selected phase offset of a reference signal transmitted to the serving base station, wherein a value of the selected phase offset indicates the MCS value selected to the serving base station.
The apparatus of any combination of claims 58-66.
An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured:

to receive, by a base station, transmit power information associated with one or more served user equipments (UEs) , wherein the transmit power information includes at least UE power class information, UE power headroom, and a per transmit antenna power restriction based on a maximum transmit power for each transmit antenna of the one or more served UEs;

to adjust, by the base station, a transmitted precoding matrix indicator (TPMI) for each of the one or more UEs to accommodate the per transmit antenna power restriction received from the one or more UEs; and

to transmit, by the base station, the adjusted TPMI to the one or more UEs.
The apparatus of claim 68, wherein the per transmit antenna power restriction includes the maximum transmit power for the each transmit antenna.
The apparatus of claim 68, wherein the per transmit antenna power restriction includes a TPMI restriction amplitude beyond which the one or more UEs would not be able to transmit within the maximum transmit power for the each transmit antenna, wherein the TPMI restriction amplitude identifies a maximum amplitude of the adjusted TPMI.
The apparatus of claim 70, further including configuration of the at least one processor:

to receive, by the base station, a TPMI restriction activation signal from the one or more UEs; and

to activate, by the base station, TPMI restriction according to the TPMI restriction amplitude in response to the TPMI restriction activation.
The apparatus of claim 68, further including configuration of the at least one processor:

to signal, by the base station, a set of modulation and coding scheme (MCS) values to the one or more UEs, wherein the set of MCS values each corresponding to a power limitation associated with one of a plurality maximum transmit powers related to one or more transmit antenna ports, wherein the per transmit antenna power restriction includes a transmission MCS selected by the one or more UEs from the set of MCS values to accommodate the maximum transmit power for the each transmit antenna.
The apparatus of claim 72, wherein the set of MCS values includes one of:

a plurality of transmission MCS values, wherein each transmission MCS value of the plurality of transmission MCS values identifies the power limitation associated with a corresponding offset MCS value; or

a plurality of offset values applicable to a configured MCS value to identify the power limitation associated with the corresponding offset MCS value.
The apparatus of claim 72, further including configuration of the at least one processor:

to receive, by the base station, uplink transmission from the one or more UEs;

to determine, by the base station, the MCS value of the set of MCS values associated with the uplink transmission; and

to determine, by the base station, the per transmit antenna power restriction corresponding to the MCS value.
The apparatus of claim 74, wherein the configuration of the at least one processor to determine the MCS value includes configuration of the at least one processor to one of:

perform blind detection on the uplink transmission based on the set of MCS values; or

identify a phase offset of a reference signal received from the one or more UEs, wherein a value of the phase offset indicates the MCS value.
The apparatus of any combination of claims 68-75.