WO2020252656A1

WO2020252656A1 - Uplink beam management for a user equipment in a low-mobility mode

Info

Publication number: WO2020252656A1
Application number: PCT/CN2019/091689
Authority: WO
Inventors: Fan Shen; Haojun WANG; Hanning Li
Original assignee: Qualcomm Incorporated
Priority date: 2019-06-18
Filing date: 2019-06-18
Publication date: 2020-12-24

Abstract

In an embodiment, a UE transmits, to a base station, an indication that the UE is operating in accordance with a low-mobility mode. The base station selects a set of beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication. The base station transmits an indication of the set of uplink beams to the UE. In some designs, the UE may then transmit data on each of the set of uplink beams in accordance with the received indication.

Description

UPLINK BEAM MANAGEMENT FOR A USER EQUIPMENT IN A LOW-MOBILITY MODE

Various aspects described herein generally relate to uplink beam management for a user equipment (UE) , whereby a number of uplink beams indicated to the UE is based on whether the UE is operating in accordance with a low-mobility mode.

INTRODUCTION

Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G) , a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks) , a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax) . There are presently many different types of wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS) , and digital cellular systems based on Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , the Global System for Mobile access (GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.

Some wireless communication networks, such as 5G, support operation at very high and even extremely-high frequency (EHF) bands, such as millimeter wave (mmW) frequency bands (generally, wavelengths of 1mm to 10mm, or 30 to 300GHz) . These extremely high frequencies may support very high throughput such as up to six gigabits per second (Gbps) . One of the challenges for wireless communication at very high or extremely high frequencies, however, is that a significant propagation loss may occur due to the high frequency. As the frequency increases, the wavelength may decrease, and the propagation loss may increase as well. At mmW frequency bands, the propagation loss may be severe. For example, the propagation loss may be on the order of 22 to 27 dB, relative to that observed in either the 2.4 GHz, or 5 GHz bands.

Propagation loss is also an issue in Multiple Input-Multiple Output (MIMO) and massive MIMO systems in any band. The term MIMO as used herein will generally refer to both MIMO and massive MIMO. MIMO is a method for multiplying the capacity of a radio link by using multiple transmit and receive antennas to exploit multipath propagation. Multipath propagation occurs because radio frequency (RF) signals not only travel by the shortest path between the transmitter and receiver, which may be a line of sight (LOS) path, but also over a number of other paths as they spread out from the transmitter and reflect off other objects such as hills, buildings, water, and the like on their way to the receiver. A transmitter in a MIMO system includes multiple antennas and takes advantage of multipath propagation by directing these antennas to each transmit the same RF signals on the same radio channel to a receiver. The receiver is also equipped with multiple antennas tuned to the radio channel that can detect the RF signals sent by the transmitter. As the RF signals arrive at the receiver (some RF signals may be delayed due to the multipath propagation) , the receiver can combine them into a single RF signal. Because the transmitter sends each RF signal at a lower power level than it would send a single RF signal, propagation loss is also an issue in a MIMO system.

To address propagation loss issues in mmW band systems and MIMO systems, transmitters may use beamforming to extend RF signal coverage. In particular, transmit beamforming is a technique for emitting an RF signal in a specific direction, whereas receive beamforming is a technique used to increase receive sensitivity of RF signals that arrive at a receiver along a specific direction. Transmit beamforming and receive beamforming may be used in conjunction with each other or separately, and references to “beamforming” may hereinafter refer to transmit beamforming, receive beamforming, or both. Traditionally, when a transmitter broadcasts an RF signal, it broadcasts the RF signal in nearly all directions determined by the fixed antenna pattern or radiation pattern of the antenna. With beamforming, the transmitter determines where a given receiver is located relative to the transmitter and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal for the receiver. To change the directionality of the RF signal when transmitting, a transmitter can control the phase and relative amplitude of the RF signal broadcasted by each antenna. For example, a transmitter may use an array of antennas (also referred to as a “phased array” or an “antenna array” ) that creates a beam of RF waves that can be “steered” to point in different directions, without actually moving the antennas. Specifically, the RF current is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling the radio waves from the separate antennas to suppress radiation in undesired directions.

SUMMARY

An aspect is directed to a method of operating a user equipment (UE) , comprising transmitting, to a base station, an indication that the UE is operating in accordance with a low-mobility mode, and receiving an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.

Another aspect is directed to a method of operating a base station, comprising receiving, from a first user equipment (UE) , an indication that the first UE is operating in accordance with a low-mobility mode, selecting a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication, and transmitting an indication of the first set of uplink beams to the UE.

Another aspect is directed to a UE, comprising a memory, a transceiver, and at least one processor coupled to the memory and the transceiver and configured to transmit, to a base station, an indication that the UE is operating in accordance with a low-mobility mode, and receive an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.

Another aspect is directed to a base station, comprising a memory, a transceiver, and at least one processor coupled to the memory and the transceiver and configured to receive, from a UE, an indication that the first UE is operating in accordance with a low-mobility mode, select a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication, and transmit an indication of the first set of uplink beams to the UE.

Another aspect is directed to a UE, comprising means for transmitting, to a base station, an indication that the UE is operating in accordance with a low-mobility mode, and means for receiving an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.

Another aspect is directed to a base station, comprising means for receiving, from a UE, an indication that the first UE is operating in accordance with a low-mobility mode, means for selecting a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication, and means for transmitting an indication of the first set of uplink beams to the UE.

Another aspect is directed to a non-transitory computer-readable medium containing instructions stored thereon, which, when executed by a UE, causes the UE to performs operations, the instructions comprising at least one instruction to cause the UE to transmit, to a base station, an indication that the UE is operating in accordance with a low-mobility mode, and at least one instruction to cause the UE to receive an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.

Another aspect is directed to a non-transitory computer-readable medium containing instructions stored thereon, which, when executed by a base station, causes the base station to performs operations, the instructions comprising at least one instruction to cause the base station to receive, from a UE, an indication that the first UE is operating in accordance with a low-mobility mode, at least one instruction to cause the base station to select a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication, and at least one instruction to cause the base station to transmit an indication of the first set of uplink beams to the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the various aspects described herein and many attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings which are presented solely for illustration and not limitation, and in which:

FIG. 1 illustrates an exemplary wireless communications system, according to various aspects.

FIGS. 2A and 2B illustrate example wireless network structures, according to various aspects.

FIG. 3A illustrates an exemplary base station and an exemplary user equipment (UE) in an access network, according to various aspects.

FIG. 3B illustrates an exemplary server according to various aspects.

FIG. 4 illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 5 illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 6 illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 7 illustrates a beam selection procedure performed with respect to the wireless communications system of FIG. 6.

FIG. 8A illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 8B illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 9 illustrates an exemplary mobility-based UL beam determination process according to an aspect of the disclosure.

FIG. 10 illustrates an exemplary mobility-based UL beam selection process according to an aspect of the disclosure.

FIG. 11 illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIG. 12 illustrates an exemplary wireless communications system according to various aspects of the disclosure.

FIGS. 13-14 illustrate example implementations of the processes of FIGS. 9-10 in accordance with aspects of the disclosure.

FIG. 15 illustrates an example UE for implementing the process of FIG. 9 represented as a series of interrelated functional modules in accordance with an aspect of the disclosure.

FIG. 16 illustrates an example base station for implementing the process of FIG. 10 represented as a series of interrelated functional modules in accordance with an aspect of the disclosure.

DETAILED DESCRIPTION

Various aspects described herein generally relate to uplink beam management for a user equipment (UE) in a low-mobility mode. In one aspect, the UE transmits, to a base station, an indication that the UE is operating in accordance with a low-mobility mode. The base station selects a set of beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication. The UE receives the indication from the base station. In some implementations, the UE can thereafter transmit on the set of beams in a manner that saves power and/or increases transmission efficiency relative to a beam allocation scheme used for more other UEs having a higher mobility.

In some designs, a higher number of uplink beams in the first set of uplink beams is correlated with a higher bit-rate for the transmission of the data. For example, the number of beams in the first set of uplink beams is denoted as 2 ^K, and a number of additional bits per symbol that can be transmitted by the UE over the first set of uplink beams relative to a number of bits that can be transmitted by the UE per symbol over a single uplink beam is based on K.

In some designs, the UE is permanently or semi-permanently operates in accordance with the low-mobility mode (e.g., an appliance such as a refrigerator or dishwasher, a set-top box, etc. ) . In other designs, the UE intermittently operates in accordance with the low-mobility mode (e.g., a mobile phone that is stationary while charging for a few hours) . In this case, the UE can toggle back and forth between a low-mobility mode and a normal mobility mode, with its beam allocation being updated accordingly.

In some designs, the number of the set of uplink beams is greater than a number of beams on the uplink channel allocated by the base station to UEs associated with a mobility that is higher than a mobility associated with the low-mobility mode. In this case, lower-mobility UEs will be able to opportunistically transmit on more uplink beams relative to more highly mobile UEs.

These and other aspects are disclosed in the following description and related drawings to show specific examples relating to exemplary aspects. Alternate aspects will be apparent to those skilled in the pertinent art upon reading this disclosure, and may be constructed and practiced without departing from the scope or spirit of the disclosure. Additionally, well-known elements will not be described in detail or may be omitted so as to not obscure the relevant details of the aspects disclosed herein.

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects” does not require that all aspects include the discussed feature, advantage, or mode of operation.

The terminology used herein describes particular aspects only and should not be construed to limit any aspects disclosed herein. As used herein, the singular forms “a, ” “an, ” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Those skilled in the art will further understand that the terms “comprises, ” “comprising, ” “includes, ” and/or “including, ” as used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Further, various aspects may be described in terms of sequences of actions to be performed by, for example, elements of a computing device. Those skilled in the art will recognize that various actions described herein can be performed by specific circuits (e.g., an application specific integrated circuit (ASIC) ) , by program instructions being executed by one or more processors, or by a combination of both. Additionally, these sequences of actions described herein can be considered to be embodied entirely within any form of non-transitory computer-readable medium having stored thereon a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects described herein may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, “logic configured to” and/or other structural components configured to perform the described action.

As used herein, the terms “user equipment” (or “UE” ) , “user device, ” “user terminal, ” “client device, ” “communication device, ” “wireless device, ” “wireless communications device, ” “handheld device, ” “mobile device, ” “mobile terminal, ” “mobile station, ” “handset, ” “access terminal, ” “subscriber device, ” “subscriber terminal, ” “subscriber station, ” “terminal, ” and variants thereof may interchangeably refer to any suitable mobile or stationary device that can receive wireless communication and/or navigation signals. These terms are also intended to include devices which communicate with another device that can receive wireless communication and/or navigation signals such as by short-range wireless, infrared, wireline connection, or other connection, regardless of whether satellite signal reception, assistance data reception, and/or position-related processing occurs at the device or at the other device. In addition, these terms are intended to include all devices, including wireless and wireline communication devices, that can communicate with a core network via a radio access network (RAN) , and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over a wired access network, a wireless local area network (WLAN) (e.g., based on IEEE 802.11, etc. ) and so on. UEs can be embodied by any of a number of types of devices including but not limited to printed circuit (PC) cards, compact flash devices, external or internal modems, wireless or wireline phones, smartphones, tablets, tracking devices, asset tags, and so on. A communication link through which UEs can send signals to a RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc. ) . A communication link through which the RAN can send signals to UEs is called a downlink or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc. ) . As used herein the term traffic channel (TCH) can refer to either an uplink /reverse or downlink /forward traffic channel.

According to various aspects, FIG. 1 illustrates an exemplary wireless communications system 100. The wireless communications system 100 (which may also be referred to as a wireless wide area network (WWAN) ) may include various base stations 102 and various UEs 104. The base stations 102 may include macro cells (high power cellular base stations) and/or small cells (low power cellular base stations) , wherein the macro cells may include Evolved NodeBs (eNBs) , where the wireless communications system 100 corresponds to an LTE network, or gNodeBs (gNBs) , where the wireless communications system 100 corresponds to a 5G network or a combination of both, and the small cells may include femtocells, picocells, microcells, etc.

The base stations 102 may collectively form a Radio Access Network (RAN) and interface with an Evolved Packet Core (EPC) or Next Generation Core (NGC) through backhaul links. In addition to other functions, the base stations 102 may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC /NGC) over backhaul links 134, which may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. In an aspect, although not shown in FIG. 1, geographic coverage areas 110 may be subdivided into a plurality of cells (e.g., three) , or sectors, each cell corresponding to a single antenna or array of antennas of a base station 102. As used herein, the term “cell” or “sector” may correspond to one of a plurality of cells of a base station 102, or to the base station 102 itself, depending on the context.

While neighboring macro cell geographic coverage areas 110 may partially overlap (e.g., in a handover region) , some of the geographic coverage areas 110 may be substantially overlapped by a larger geographic coverage area 110. For example, a small cell base station 102'may have a geographic coverage area 110'that substantially overlaps with the geographic coverage area 110 of one or more macro cell base stations 102. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home eNBs (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) .

The wireless communications system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with WLAN stations (STAs) 152 via communication links 154 in an unlicensed frequency spectrum (e.g., 5 GHz) . When communicating in an unlicensed frequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell base station 102'may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102'may employ LTE or 5G technology and use the same 5 GHz unlicensed frequency spectrum as used by the WLAN AP 150. The small cell base station 102', employing LTE /5G in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. LTE in an unlicensed spectrum may be referred to as LTE-unlicensed (LTE-U) , licensed assisted access (LAA) , or MulteFire.

The wireless communications system 100 may further include a mmW base station 180 that may operate in mmW frequencies and/or near mmW frequencies in communication with a UE 182. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band have high path loss and a relatively short range. The mmW base station 180 may utilize beamforming 184 with the UE 182 to compensate for the extremely high path loss and short range. Further, it will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Accordingly, it will be appreciated that the foregoing illustrations are merely examples and should not be construed to limit the various aspects disclosed herein.

The wireless communications system 100 may further include one or more UEs, such as UE 190, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the aspect of FIG. 1, UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which UE 190 may indirectly obtain cellular connectivity) and a D2D P2P link 194 with WLAN STA 152 connected to the WLAN AP 150 (through which UE 190 may indirectly obtain WLAN-based Internet connectivity) . In an example, the D2D P2P links 192-194 may be supported with any well-known D2D radio access technology (RAT) , such as LTE Direct (LTE-D) , WiFi Direct (WiFi-D) , Bluetooth, and so on.

According to various aspects, FIG. 2A illustrates an example wireless network structure 200. For example, an NGC 210 can be viewed functionally as control plane functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc. ) , and user plane functions 212 (e.g., UE gateway function, access to data networks, Internet protocol (IP) routing, etc. ) , which operate cooperatively to form the core network. User plane interface (NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 to the NGC 210 and specifically to the control plane functions 214 and user plane functions 212. In an additional configuration, an eNB 224 may also be connected to the NGC 210 via NG-C 215 to the control plane functions 214 and NG-U 213 to user plane functions 212. Further, eNB 224 may directly communicate with gNB 222 via a backhaul connection 223. Accordingly, in some configurations, the New RAN 220 may only have one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicate with UEs 240 (e.g., any of the UEs depicted in FIG. 1, such as UEs 104, UE 152, UE 182, UE 190, etc. ) . Another optional aspect may include a location server 230 that may be in communication with the NGC 210 to provide location assistance for UEs 240. The location server 230 can be implemented as a plurality of structurally separate servers, or alternately may each correspond to a single server. The location server 230 can be configured to support one or more location services for UEs 240 that can connect to the location server 230 via the core network, NGC 210, and/or via the Internet (not illustrated) . Further, the location server 230 may be integrated into a component of the core network, or alternatively may be external to the core network.

Further illustrated in FIG. 1 is an example UE 100A and an example base station 100B. The UE 100A includes at least a transceiver 102A and a beam transmission controller 104A, and the base station 100B includes at least a transceiver 102B, and a beam selection controller 104B. As will be described in more detail below, the beam selection controller 104B (e.g., which may be implemented as a processing function via a processor on the base station 100B) executes logic so as to select uplink beam (s) on which the UE 100A may transmit based upon a mobility mode indication from the UE 100A, and to provide an indication of the beam selection via a signal from the transceiver 102B. Also, the beam transmission controller 104A (e.g., which may be implemented as a processing function via a processor on the UE 100A) executes logic so opportunistically transmit data on one or more of the selected beams conveyed by the indication from the base station 100B. The UE 100A and base station 100B are intended to be representative of various exemplary UEs and base stations that may carry out certain aspects of the present disclosure. Accordingly, the UE 100A and base station 100B appear in certain FIGS below to emphasize the configurations of various UEs and base stations. Moreover, the UE 1500 of FIG. 15 and base station 1600 of FIG. 16 illustrate more detailed implementation examples of the UE 100A and base station 100B in accordance with various aspects.

According to various aspects, FIG. 2B illustrates another example wireless network structure 250. For example, an NGC 260 can be viewed functionally as control plane functions, an access and mobility management function (AMF) 264 and user plane functions, and a session management function (SMF) 262, which operate cooperatively to form the core network. User plane interface 263 and control plane interface 265 connect the eNB 224 to the NGC 260 and specifically to AMF 264 and SMF 262. In an additional configuration, a gNB 222 may also be connected to the NGC 260 via control plane interface 265 to AMF 264 and user plane interface 263 to SMF 262. Further, eNB 224 may directly communicate with gNB 222 via the backhaul connection 223, with or without gNB direct connectivity to the NGC 260. Accordingly, in some configurations, the New RAN 220 may only have one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicate with UEs 240 (e.g., any of the UEs depicted in FIG. 1, such as UEs 104, UE 182, UE 190, etc. ) . Another optional aspect may include a location management function (LMF) 270, which may be in communication with the NGC 260 to provide location assistance for UEs 240. The LMF 270 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc. ) , or alternately may each correspond to a single server. The LMF 270 can be configured to support one or more location services for UEs 240 that can connect to the LMF 270 via the core network, NGC 260, and/or via the Internet (not illustrated) .

According to various aspects, FIG. 3A illustrates an exemplary base station (BS) 310 (e.g., an eNB, a gNB, a small cell AP, a WLAN AP, etc. ) in communication with an exemplary UE 350 (e.g., any of the UEs depicted in FIG. 1, such as UEs 104, UE 152, UE 182, UE 190, etc. ) in a wireless network. In the DL, IP packets from the core network (NGC 210 /EPC 260) may be provided to a controller/processor 375. The controller/processor 375 implements functionality for a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB) , system information blocks (SIBs) ) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through automatic repeat request (ARQ) , concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement Layer-1 functionality associated with various signal processing functions. Layer-1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an orthogonal frequency-division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to one or more different antennas 320 via a separate transmitter 318a. Each transmitter 318a may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354a receives a signal through its respective antenna 352. Each receiver 354a recovers information modulated onto an RF carrier and provides the information to the RX processor 356. The TX processor 368 and the RX processor 356 implement Layer-1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the processing system 359, which implements Layer-3 and Layer-2 functionality.

The processing system 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a non-transitory computer-readable medium. In the UL, the processing system 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network. The processing system 359 is also responsible for error detection.

Similar to the functionality described in connection with the DL transmission by the base station 310, the processing system 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ) , priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354b. Each transmitter 354b may modulate an RF carrier with a respective spatial stream for transmission. In an aspect, the transmitters 354b and the receivers 354a may be one or more transceivers, one or more discrete transmitters, one or more discrete receivers, or any combination thereof.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318b receives a signal through its respective antenna 320. Each receiver 318b recovers information modulated onto an RF carrier and provides the information to a RX processor 370. In an aspect, the transmitters 318a and the receivers 318b may be one or more transceivers, one or more discrete transmitters, one or more discrete receivers, or any combination thereof.

The processing system 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a non-transitory computer-readable medium. In the UL, the processing system 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the processing system 375 may be provided to the core network. The processing system 375 is also responsible for error detection.

FIG. 3B illustrates an exemplary server 300B. In an example, the server 300B may correspond to one example configuration of the location server 230 described above. In FIG. 3B, the server 300B includes a processor 301B coupled to volatile memory 302B and a large capacity nonvolatile memory, such as a disk drive 303B. The server 300B may also include a floppy disc drive, compact disc (CD) or DVD disc drive 306B coupled to the processor 301B. The server 300B may also include network access ports 304B coupled to the processor 301B for establishing data connections with a network 307B, such as a local area network coupled to other broadcast system computers and servers or to the Internet.

FIG. 4 illustrates an exemplary wireless communications system 400 according to various aspects of the disclosure. In the example of FIG. 4, a UE 404, which may correspond to any of the UEs described above with respect to FIG. 1 (e.g., UEs 104, UE 182, UE 190, etc. ) , is attempting to calculate an estimate of its position, or assist another entity (e.g., a base station or core network component, another UE, a location server, a third party application, etc. ) to calculate an estimate of its position. The UE 404 may communicate wirelessly with a plurality of base stations 402a-d (collectively, base stations 402) , which may correspond to any combination of

base stations

102 or 180 and/or WLAN AP 150 in FIG. 1, using RF signals and standardized protocols for the modulation of the RF signals and the exchange of information packets. By extracting different types of information from the exchanged RF signals, and utilizing the layout of the wireless communications system 400 (i.e., the base stations locations, geometry, etc. ) , the UE 404 may determine its position, or assist in the determination of its position, in a predefined reference coordinate system. In an aspect, the UE 404 may specify its position using a two-dimensional coordinate system; however, the aspects disclosed herein are not so limited, and may also be applicable to determining positions using a three-dimensional coordinate system, if the extra dimension is desired. Additionally, while FIG. 4 illustrates one UE 404 and four base stations 402, as will be appreciated, there may be more UEs 404 and more or fewer base stations 402.

To support position estimates, the base stations 402 may be configured to broadcast reference RF signals (e.g., Positioning Reference Signals (PRS) , Cell-specific Reference Signals (CRS) , Channel State Information Reference Signals (CSI-RS) , synchronization signals, etc. ) to UEs 404 in their coverage area to enable a UE 404 to measure reference RF signal timing differences (e.g., OTDOA or RSTD) between pairs of network nodes and/or to identify the beam that best excite the LOS or shortest radio path between the UE 404 and the transmitting base stations 402. Identifying the LOS/shortest path beam (s) is of interest not only because these beams can subsequently be used for OTDOA measurements between a pair of base stations 402, but also because identifying these beams can directly provide some positioning information based on the beam direction. Moreover, these beams can subsequently be used for other position estimation methods that require precise ToA, such as round-trip time estimation based methods.

As used herein, a “network node” may be a base station 402, a cell of a base station 402, a remote radio head, an antenna of a base station 402, where the locations of the antennas of a base station 402 are distinct from the location of the base station 402 itself, or any other network entity capable of transmitting reference signals. Further, as used herein, a “node” may refer to either a network node or a UE.

A location server (e.g., location server 230) may send assistance data to the UE 404 that includes an identification of one or more neighbor cells of base stations 402 and configuration information for reference RF signals transmitted by each neighbor cell. Alternatively, the assistance data can originate directly from the base stations 402 themselves (e.g., in periodically broadcasted overhead messages, etc. ) . Alternatively, the UE 404 can detect neighbor cells of base stations 402 itself without the use of assistance data. The UE 404 (e.g., based in part on the assistance data, if provided) can measure and (optionally) report the OTDOA from individual network nodes and/or RSTDs between reference RF signals received from pairs of network nodes. Using these measurements and the known locations of the measured network nodes (i.e., the base station (s) 402 or antenna (s) that transmitted the reference RF signals that the UE 404 measured) , the UE 404 or the location server can determine the distance between the UE 404 and the measured network nodes and thereby calculate the location of the UE 404.

The term “position estimate” is used herein to refer to an estimate of a position for a UE 404, which may be geographic (e.g., may comprise a latitude, longitude, and possibly altitude) or civic (e.g., may comprise a street address, building designation, or precise point or area within or nearby to a building or street address, such as a particular entrance to a building, a particular room or suite in a building, or a landmark such as a town square) . A position estimate may also be referred to as a “location, ” a “position, ” a “fix, ” a “position fix, ” a “location fix, ” a “location estimate, ” a “fix estimate, ” or by some other term. The means of obtaining a location estimate may be referred to generically as “positioning, ” “locating, ” or “position fixing. ” A particular solution for obtaining a position estimate may be referred to as a “position solution. ” A particular method for obtaining a position estimate as part of a position solution may be referred to as a “position method” or as a “positioning method. ”

The term “base station” may refer to a single physical transmission point or to multiple physical transmission points that may or may not be co-located. For example, where the term “base station” refers to a single physical transmission point, the physical transmission point may be an antenna of the base station (e.g., base station 402) corresponding to a cell of the base station. Where the term “base station” refers to multiple co-located physical transmission points, the physical transmission points may be an array of antennas (e.g., as in a MIMO system or where the base station employs beamforming) of the base station. Where the term “base station” refers to multiple non-co-located physical transmission points, the physical transmission points may be a Distributed Antenna System (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a Remote Radio Head (RRH) (a remote base station connected to a serving base station) . Alternatively, the non-co-located physical transmission points may be the serving base station receiving the measurement report from the UE (e.g., UE 404) and a neighbor base station whose reference RF signals the UE is measuring. Thus, FIG. 4 illustrates an aspect in which

base stations

402a and 402b form a DAS /RRH 420. For example, the base station 402a may be the serving base station of the UE 404 and the base station 402b may be a neighbor base station of the UE 404. As such, the base station 402b may be the RRH of the base station 402a. The

base stations

402a and 402b may communicate with each other over a wired or wireless link 422.

To accurately determine the position of the UE 404 using the OTDOAs and/or RSTDs between RF signals received from pairs of network nodes, the UE 404 needs to measure the reference RF signals received over the LOS path (or the shortest NLOS path where an LOS path is not available) , between the UE 404 and a network node (e.g., base station 402, antenna) . However, RF signals travel not only by the LOS /shortest path between the transmitter and receiver, but also over a number of other paths as the RF signals spread out from the transmitter and reflect off other objects such as hills, buildings, water, and the like on their way to the receiver. Thus, FIG. 4 illustrates a number of LOS paths 410 and a number of NLOS paths 412 between the base stations 402 and the UE 404. Specifically, FIG. 4 illustrates base station 402a transmitting over an LOS path 410a and an NLOS path 412a, base station 402b transmitting over an LOS path 410b and two NLOS paths 412b, base station 402c transmitting over an LOS path 410c and an NLOS path 412c, and base station 402d transmitting over two NLOS paths 412d. As illustrated in FIG. 4, each NLOS path 412 reflects off some object 430 (e.g., a building) . As will be appreciated, each LOS path 410 and NLOS path 412 transmitted by a base station 402 may be transmitted by different antennas of the base station 402 (e.g., as in a MIMO system) , or may be transmitted by the same antenna of a base station 402 (thereby illustrating the propagation of an RF signal) . Further, as used herein, the term “LOS path” refers to the shortest path between a transmitter and receiver, and may not be an actual LOS path, but rather, the shortest NLOS path.

In an aspect, one or more of base stations 402 may be configured to use beamforming to transmit RF signals. In that case, some of the available beams may focus the transmitted RF signal along the LOS paths 410 (e.g., the beams produce highest antenna gain along the LOS paths) while other available beams may focus the transmitted RF signal along the NLOS paths 412. A beam that has high gain along a certain path and thus focuses the RF signal along that path may still have some RF signal propagating along other paths; the strength of that RF signal naturally depends on the beam gain along those other paths. An “RF signal” comprises an electromagnetic wave that transports information through the space between the transmitter and the receiver. As used herein, a transmitter may transmit a single “RF signal” or multiple “RF signals” to a receiver. However, as described further below, the receiver may receive multiple “RF signals” corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels.

Where a base station 402 uses beamforming to transmit RF signals, the beams of interest for data communication between the base station 402 and the UE 404 will be the beams carrying RF signals that arrive at UE 404 with the highest signal strength (as indicated by, e.g., the Received Signal Received Power (RSRP) or SINR in the presence of a directional interfering signal) , whereas the beams of interest for position estimation will be the beams carrying RF signals that excite the shortest path or LOS path (e.g., an LOS path 410) . In some frequency bands and for antenna systems typically used, these will be the same beams. However, in other frequency bands, such as mmW, where typically a large number of antenna elements can be used to create narrow transmit beams, they may not be the same beam. As described below with reference to FIG. 5, in some cases, the signal strength of RF signals on the LOS path 410 may be weaker (e.g., due to obstructions) than the signal strength of RF signals on an NLOS path 412, over which the RF signals arrive later due to propagation delay.

While FIG. 4 is described in terms of transmissions from a base station to a UE, it will be appreciated that the downlink RF signal paths described with respect to FIG. 4 are equally applicable to transmissions from a UE to a base station where the UE is capable of MIMO operation and/or beamforming. Also, while beamforming is generally described above in context with transmit beamforming, receive beamforming may also be used in conjunction with the above-noted transmit beamforming in certain aspects.

FIG. 5 illustrates an exemplary wireless communications system 500 according to various aspects of the disclosure. In the example of FIG. 5, a UE 504, which may correspond to UE 404 in FIG. 4, is attempting to calculate an estimate of its position, or to assist another entity (e.g., a base station or core network component, another UE, a location server, a third party application, etc. ) to calculate an estimate of its position. The UE 504 may communicate wirelessly with a base station 502, which may correspond to one of base stations 402 in FIG. 4, using RF signals and standardized protocols for the modulation of the RF signals and the exchange of information packets.

As illustrated in FIG. 5, the base station 502 is utilizing beamforming to transmit a plurality of beams 511 –515 of RF signals. Each beam 511 –515 may be formed and transmitted by an array of antennas of the base station 502. Although FIG. 5 illustrates a base station 502 transmitting five beams, as will be appreciated, there may be more or fewer than five beams, beam shapes such as peak gain, width, and side-lobe gains may differ amongst the transmitted beams, and some of the beams may be transmitted by a different base station.

A beam index may be assigned to each of the plurality of beams 511 –515 for purposes of distinguishing RF signals associated with one beam from RF signals associated with another beam. Moreover, the RF signals associated with a particular beam of the plurality of beams 511 –515 may carry a beam index indicator. A beam index may also be derived from the time of transmission, e.g., frame, slot and/or OFDM symbol number, of the RF signal. The beam index indicator may be, for example, a three-bit field for uniquely distinguishing up to eight beams. If two different RF signals having different beam indices are received, this would indicate that the RF signals were transmitted using different beams. If two different RF signals share a common beam index, this would indicate that the different RF signals are transmitted using the same beam. Another way to describe that two RF signals are transmitted using the same beam is to say that the antenna port (s) used for the transmission of the first RF signal are spatially quasi-collocated with the antenna port (s) used for the transmission of the second RF signal.

In the example of FIG. 5, the UE 504 receives an NLOS data stream 523 of RF signals transmitted on beam 513 and an LOS data stream 524 of RF signals transmitted on beam 514. Although FIG. 5 illustrates the NLOS data stream 523 and the LOS data stream 524 as single lines (dashed and solid, respectively) , as will be appreciated, the NLOS data stream 523 and the LOS data stream 524 may each comprise multiple rays (i.e., a “cluster” ) by the time they reach the UE 504 due, for example, to the propagation characteristics of RF signals through multipath channels. For example, a cluster of RF signals is formed when an electromagnetic wave is reflected off of multiple surfaces of an object, and reflections arrive at the receiver (e.g., UE 504) from roughly the same angle, each travelling a few wavelengths (e.g., centimeters) more or less than others. A “cluster” of received RF signals generally corresponds to a single transmitted RF signal.

In the example of FIG. 5, the NLOS data stream 523 is not originally directed at the UE 504, although, as will be appreciated, it could be, as are the RF signals on the NLOS paths 412 in FIG. 4. However, it is reflected off a reflector 540 (e.g., a building) and reaches the UE 504 without obstruction, and therefore, may still be a relatively strong RF signal. In contrast, the LOS data stream 524 is directed at the UE 504 but passes through an obstruction 530 (e.g., vegetation, a building, a hill, a disruptive environment such as clouds or smoke, etc. ) , which may significantly degrade the RF signal. As will be appreciated, although the LOS data stream 524 is weaker than the NLOS data stream 523, the LOS data stream 524 will arrive at the UE 504 before the NLOS data stream 523 because it follows a shorter path from the base station 502 to the UE 504.

In at least one conventional 5G NR system implementation, for supporting mobility of a UE, a 5G NR base station (or gNB) may detect a quality of each uplink (UL) channels (e.g., antenna or beam) repeatedly (or continuously) to dynamically schedule (or assign) the best antenna or beams to the UE for UL transmission. However, such mobility optimizations may not provide benefit to UEs operating in accordance with a low-mobility mode (e.g., UEs that are stationary or fixed, or moving below some speed threshold) . Examples of UE types that often operate in such a low-mobility mode include millimeter wave (MMwave) , IoT devices (e.g., stationary appliances such as dishwashers, refrigerators, microwaves, etc. ) , and so on.

In theory, the antenna/beam detection process of the 5G NR base station is useful to identify the best beams from among a set of unknown beams (since the best beams may change frequency due to the mobility of the UEs) . In at least one conventional 5G NR system implementation, the beam selection process does not involve an exchange of information between the UE and gNB beyond beam-specific information.

FIG. 6 illustrates an exemplary wireless communications system 600 according to various aspects of the disclosure. In FIG. 6, a base station 605 performs measurements on a plurality of uplink beams 1…N from a UE 610. The base station selects a beam based on these measurements, and conveys the selected beam back to the UE 610 over a signaling channel 605.

FIG. 7 illustrates a beam selection procedure performed with respect to the wireless communications system 600. Referring to FIG. 7, at block 702, the base station 605 evaluates UL beams 1…N from UE 610. At block 704, the base station 704 selects beam M as the best available UL beam for UE 605 based on the evaluation. At block 706, the base station 605 transmits an indication of beam M to UE 610, which receives the beam M indication at block 708. At block 710, UE 610 transmits data on beam M in accordance with the indication, and the base station 605 receives the transmitted data on beam M at block 712, as shown in FIG. 8A. At block 714, the base station 605 again evaluates UL beams 1…N from UE 610. At block 716, the base station 704 selects beam 2 as the best available UL beam for UE 605 based on the evaluation. At block 718, the base station 605 transmits an indication of beam 2 to UE 610, which receives the beam M indication at block 720. At block 722, UE 610 transmits data on beam M in accordance with the indication, and the base station 605 receives the transmitted data on beam M at block 724, as shown in FIG. 8B.

As will be appreciated, the dynamic beam-switching that occurs in accordance with the beam selection procedure of FIG. 7 is particularly useful for highly mobile UEs whose optimal UL beams will change frequently due to their high mobility. However, the beam selection procedure of FIG. 7 is less efficient with regard to UEs operating in accordance with a low-mobility mode. Accordingly, one or more aspects of the present disclosure relate to conveying, from the UE, an indication as to whether that UE is operating in accordance with a low-mobility mode. The low-mobility mode indication may then be factored into a beam allocation to that UE, which may be used to increase transmission efficiency and/or to save power (energy consumption per bit transmitted) relative to the above-noted conventional beam allocation scheme which is optimized for mobile UEs (or UEs moving faster than a speed threshold associated with the low-mobility mode) .

FIG. 9 illustrates an exemplary mobility-based UL beam determination process 900 according to an aspect of the disclosure. The process 900 of FIG. 9 is performed by a UE 905, which may correspond to any of the above-noted UEs (e.g.,

UE

100A, 240, 350, etc. ) .

At block 902, the UE 905 (e.g., antenna (s) 320, transmitter (s) 318, and/or TX processor 316) transmits to a base station (e.g., base station 1005 of FIG. 10) , an indication that the UE is operating in accordance with a low-mobility mode. At block 904, the UE 905 (e.g., antenna (s) 352, receiver (s) 354, and/or RX processor 356) receives an indication of a set of uplink beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication. As will be explained in more detail below, the UE 905 may transmit upon the set of uplink beams based on the indication from block 904.

FIG. 10 illustrates an exemplary mobility-based UL beam selection process 1000 according to an aspect of the disclosure. The process 1000 of FIG. 10 is performed by a base station 1005. In an example, the base station 1005 may correspond to base station 100B, gNB 222, eNB 224, base station 310, etc.

At block 1002, the base station 1005 receives (e.g., antenna (s) 320, receive (s) 318, and/or RX processor 370) , from a UE (e.g., UE 905 of FIG. 9) , an indication that the first UE is operating in accordance with a low-mobility mode. At block 1004, the base station 1005 (e.g., controller/processor 375, processor 301B, etc. ) selects a set of beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication. At block 1006, the base station 1005 (e.g., antenna (s) 320, transmitter (s) 318, and/or TX processor 316) transmits an indication of the set of uplink beams to the UE. As will be explained in more detail below, the UE may transmit upon the set of uplink beams based on the indication from block 1006.

Referring to FIGS. 9-10, in some designs, the low-mobility mode may correspond to a stationary mode indicator whereby the associated UE is indicated as being completely stationary or fixed in position. In other designs, the low-mobility mode may convey that the UE is moving below a speed threshold, such as 0.5 millimeters per second, 1.0 millimeters per second, and so on.

Referring to FIGS. 11-12, in some designs, a UE may be configured for low-mobility mode on a permanent or semi-permanent basis (e.g., the UE corresponds to an installed appliance such as a microwave, refrigerator, dishwasher, etc. that generally does not change location after installation) . Alternatively, a UE may be configured for low-mobility mode on an intermittent basis (e.g., a mobile phone, tablet computer, electric vehicle, etc. that is stationary while charging overnight (or parked) while being mobile at other times) . For intermittently mobile UEs, the base station may be notified as to when the UEs transition into and out of the low-mobility mode, and the base station may update the beam allocation (e.g., number of beams) accordingly. For example, a higher number of beams (lower L value) may be allocated to an intermittently mobile UE when the UE is in the low-mobility mode as compared to when the intermittently mobile UE not in the low-mobility mode (or put another way, when the intermittently mobile UE is associated with a mobility that is higher than a mobility associated with the low-mobility mode) . Similarly, any other UEs which are not in the low-mobility mode (or at least, not known by the base station to be in a low-mobility mode, such as a charging mobile phone that does not tell the base station that it has stopped moving) may likewise be allocated to a lower number of uplink beams as compared to a UE that is known to be operating in accordance with the low-mobility mode. In some designs, this lower number of beams may be the same as the lower number of beams allocated to an intermittently mobile UE that is not currently operating in accordance with the low-mobility mode, although different beam allocations could be used for such UEs in other aspects.

Referring to FIGS. 9-10, in some designs, a higher number of uplink beams in the set of uplink beams is correlated with a higher bit-rate for the transmission of the data by the UE. In an example, assume that the number of beams (denoted as L) in the set of uplink beams is denoted as 2 ^K, such that L = 2 ^K. In this case, a number of additional bits per symbol that can be transmitted by the UE over the set of uplink beams relative to a number of bits that can be transmitted by the UE per symbol over a single uplink beam (or L = 1) is based on K.

FIGS. 11-12 illustrate the higher bit-rates that can be achieved at higher L values in accordance with an aspect of the disclosure. In particular, FIG. 11 illustrates a 5G-specific example whereby L = 8 for a Single Input Single Output (SISO) implementation (FIG. 11) and FIG. 12 illustrates a 5G-specific example whereby L = 8 for a MIMO implementation. In FIG. 11, 3 additional bits can be transmitted per beam in association with the transmission of one UL symbol. In FIG. 12, 2 additional bits can be transmitted per pair of beams in association with the transmission of two UL symbols.

Referring to FIGS. 11-12, in one example, assume that a UE transmits data only on one of 8 beams. Before a positive detection, the receiver (e.g., eNB) does not know which beam (s) the UE will be using for transmission of data. After the positive detection, the receiver (e.g., eNB) knows the precise beam (s) the UE is using for the transmission of the data. In other words, the UE can transmit a number (ranged 1 to 8, in this example, which maps to 3 bits since 3 bits can convey 8 unique values or beam indexes) to the receiver (e.g., gNB) based on the number of beams used for the transmission of data. In this case, the data gain depends on how many probable beams the UE can select. For example, if the UE selected 1 beam from 8, the probability is 1/8, and the gain would be 3 bits. In a more complicated example, if the UE selects 2 beams from 8, the probability is 1/C ₈ ² = 1/28, 1/32 < 1/28 < 1/16, 16 probability exist, so the gain would be 4 bits at least.

FIGS. 13-14 illustrate example implementations of the processes 900-1000 of FIGS. 9-10 in accordance with aspects of the disclosure.

Referring to FIG. 13, at block 1302, UE 1 transmits an indication that UE 1 is operating in accordance with a low-mobility mode to a base station, and the base station receives the indication at block 1304. At block 1306, the base station evaluates UL beams 1…N from UE 1. At block 1308, the base station 704 selects a set of beams for allocation to UE 1 based on the evaluation, with a number of beams in the set of uplink beams being based in part upon the low-mobility mode indication. At block 1310, the base station transmits an indication of the = set of beams to UE 1, which receives the indication at block 1312. At block 1314, UE 1 transmits data on the set of beams in accordance with the indication, and the base station receives the transmitted data on the set of beams at block 1316.

In contrast to FIG. 7, at this point the base station need not continuously and repeatedly re-evaluate the beam allocation to UE 1. Rather, because UE 1 is known to be in the low-mobility mode, the beam allocation to UE 1 is static or semi-static, although certain triggers (e.g., an indication that the UE is no longer in low-mobility mode or detection of very poor traffic conditions on certain beams which indicates that the optimal beam allocation has changed) and/or long-interval periodic checks (e.g., longer than the intervals used in FIG. 7 which are effectively continuous) at which the beam allocation is reevaluated can be implemented. In any case, the lower frequency at which the beam allocation to UE 1 is re-evaluated results in power savings, and the increased number of allocated beams to UE 1 results in increased efficiency in data traffic communications as noted above with respect to FIGS. 11-12.

FIG. 14 illustrates a continuation of the process of FIG. 13 in accordance with an aspect of the disclosure. In particular, FIG. 14 relates to an example scenario where UE 1 is an intermittently mobile UE. At some point after 1316, at block 1402, UE 1 determines that UE 1 is no longer operating in accordance with the low-mobility mode. At block 1404, UE 1 transmits an indication that UE 1 is no longer operating in accordance with the low-mobility mode, and the indication is received at the base station at block 1406. At block 1408, the process advances to block 702 or block 714 of FIG. 7, whereby beam selection is implemented so as to account for UE mobility as described above. At block 1410, UE 1 determines that UE 1 is once again operating in accordance with the low-mobility mode, after which the process returns to block 1302 of FIG. 13.

FIG. 15 illustrates an example UE 1500 for implementing the process 900 of FIG. 9 represented as a series of interrelated functional modules in accordance with an aspect of the disclosure. In the illustrated example, the UE 1500 includes a module for transmitting 1502, and a module for receiving 1504.

The module for transmitting 1502 may be configured to transmit to a base station (e.g., base station 1005 of FIG. 10) , an indication that the UE is operating in accordance with a low-mobility mode (e.g., block 902 of FIG. 9) . The module for receiving 1504 may be configured to receive an indication of a set of uplink beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication (e.g., block 904 of FIG. 9) .

FIG. 16 illustrates an example base station 1600 for implementing the process 1000 of FIG. 10 represented as a series of interrelated functional modules in accordance with an aspect of the disclosure. In the illustrated example, the base station 1600 includes a module for receiving 1602, a module for selecting 1604, and a module for transmitting 1606.

The module for receiving 1602 may be configured to receive, from a UE, an indication that the first UE is operating in accordance with a low-mobility mode (e.g., block 1002 of FIG. 10) . The module for selecting 1604 may be configured to select a set of beams on an uplink channel, a number of beams in the set of uplink beams being based in part on the low-mobility mode indication (e.g., block 1004 of FIG. 10) . The module for transmitting 1606 may be configured to transmit an indication of the set of uplink beams to the UE. (e.g., block 1006 of FIG. 10) .

Those skilled in the art will appreciate 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.

Further, those skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed 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 to depart from the scope of the various aspects described herein.

The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed 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 other such configurations) .

The methods, sequences, and/or algorithms described in connection with the aspects disclosed 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, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory computer-readable medium known in the art. An exemplary non-transitory computer-readable medium may be coupled to the processor such that the processor can read information from, and write information to, the non-transitory computer-readable medium. In the alternative, the non-transitory computer-readable medium may be integral to the processor. The processor and the non-transitory computer-readable medium may reside in an ASIC. The ASIC may reside in a user device (e.g., a UE) or a base station. In the alternative, the processor and the non-transitory computer-readable medium may be discrete components in a user device or base station.

In one or more exemplary aspects, the functions described herein 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 non-transitory computer-readable medium. Computer-readable media may include storage media and/or communication media including any non-transitory medium that may facilitate transferring a computer program from one place to another. A storage media may be any available media that can be accessed by a 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 in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is 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, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. The term disk and disc, which may be used interchangeably herein, includes CD, laser disc, optical disc, DVD, floppy disk, and Blu-ray discs, which usually reproduce data magnetically and/or optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects, those skilled in the art will appreciate that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. Furthermore, in accordance with the various illustrative aspects described herein, those skilled in the art will appreciate that the functions, steps, and/or actions in any methods described above and/or recited in any method claims appended hereto need not be performed in any particular order. Further still, to the extent that any elements are described above or recited in the appended claims in a singular form, those skilled in the art will appreciate that singular form (s) contemplate the plural as well unless limitation to the singular form (s) is explicitly stated.

Claims

A method of operating a user equipment (UE) , comprising:

transmitting, to a base station, an indication that the UE is operating in accordance with a low-mobility mode; and

receiving an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.
The method of claim 1, further comprising:

transmitting data on each of the first set of uplink beams in accordance with the received indication.
The method of claim 2, wherein a higher number of uplink beams in the first set of uplink beams is correlated with a higher bit-rate for the transmission of the data.
The method of claim 3,

wherein the number of beams in the first set of uplink beams is denoted as 2 ^K, and

wherein a number of additional bits per symbol that can be transmitted by the UE over the first set of uplink beams relative to a number of bits that can be transmitted by the UE per symbol over a single uplink beam is based on K.
The method of claim 1, wherein the UE permanently or semi-permanently operates in accordance with the low-mobility mode.
The method of claim 1, wherein the UE intermittently operates in accordance with the low-mobility mode.
The method of claim 6, further comprising:

determining that the UE is no longer operating in accordance with the low-mobility mode;

transmitting, to the base station, an indication that the UE is no longer operating in accordance with the low-mobility mode; and

receiving, in response to the transmission of the indication that the UE is no longer operating in accordance with the low-mobility mode, an indication of a second set of uplink beams on the uplink channel, a number of beams in the second set of uplink beams being less than the number of beams in the first set of uplink beams.
The method of claim 1, wherein the number of the first set of uplink beams is greater than a number of beams on the uplink channel allocated by the base station to UEs associated with a mobility that is higher than a mobility associated with the low-mobility mode.
A method of operating a base station, comprising:

receiving, from a first user equipment (UE) , an indication that the first UE is operating in accordance with a low-mobility mode;

selecting a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication; and

transmitting an indication of the first set of uplink beams to the UE.
The method of claim 9, further comprising:

receiving data from the UE on each of the first set of uplink beams in accordance with the transmitted indication.
The method of claim 10, wherein a higher number of uplink beams in the first set of uplink beams is correlated with a higher bit-rate for the reception of the data.
The method of claim 11,

wherein the number of beams in the first set of uplink beams is denoted as 2 ^K, and

wherein a number of additional bits per symbol that can be transmitted by the first UE over the first set of uplink beams relative to a number of bits that can be transmitted by the first UE per symbol over a single uplink beam is based on K.
The method of claim 9, wherein the first UE permanently or semi-permanently operates in accordance with the low-mobility mode.
The method of claim 9, wherein the first UE intermittently operates in accordance with the low-mobility mode.
The method of claim 14, further comprising:

receiving, from the first UE, an indication that the UE is no longer operating in accordance with the low-mobility mode;

selecting a second set of beams on the uplink channel, a number of beams in the second set of uplink beams being less than the number of beams in the first set of uplink beams; and

transmitting an indication of the second set of uplink beams to the first UE.
The method of claim 9, wherein the number of beams in the first set of uplink beams is greater than a number of beams on the uplink channel allocated by the base station to UEs associated with a mobility that is higher than a mobility associated with the low-mobility mode.
The method of claim 9, further comprising:

determining that a second UE is associated with a mobility that is higher than a mobility associated with the low-mobility mode;

selecting a second set of beams on the uplink channel, a number of beams in the second set of uplink beams being less than the number of beams in the first set of uplink beams based in part on the determining; and

transmitting an indication of the second set of uplink beams to the second UE.
A user equipment (UE) , comprising:

a memory;

a transceiver; and

at least one processor coupled to the memory and the transceiver and configured to:

transmit, to a base station, an indication that the UE is operating in accordance with a low-mobility mode; and

receive an indication of a first set of uplink beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication.
The UE of claim 18, wherein the at least one processor is further configured to:

transmit data on each of the first set of uplink beams in accordance with the received indication.
The UE of claim 19, wherein a higher number of uplink beams in the first set of uplink beams is correlated with a higher bit-rate for the transmission of the data.
The UE of claim 18, wherein the UE permanently or semi-permanently operates in accordance with the low-mobility mode.
The UE of claim 18, wherein the UE intermittently operates in accordance with the low-mobility mode.
The UE of claim 18, wherein the number of the first set of uplink beams is greater than a number of beams on the uplink channel allocated by the base station to UEs associated with a mobility that is higher than a mobility associated with the low-mobility mode.
A base station, comprising:

a memory;

a transceiver; and

at least one processor coupled to the memory and the transceiver and configured to:

receive, from a first user equipment (UE) , an indication that the first UE is operating in accordance with a low-mobility mode;

select a first set of beams on an uplink channel, a number of beams in the first set of uplink beams being based in part on the low-mobility mode indication; and

transmit an indication of the first set of uplink beams to the UE.
The base station of claim 24, wherein the at least one processor is further configured to:

receive data from the UE on each of the first set of uplink beams in accordance with the transmitted indication.
The base station of claim 25, wherein a higher number of uplink beams in the first set of uplink beams is correlated with a higher bit-rate for the reception of the data.
The base station of claim 25, wherein the first UE permanently or semi-permanently operates in accordance with the low-mobility mode.
The base station of claim 24, wherein the first UE intermittently operates in accordance with the low-mobility mode.
The base station of claim 28, wherein the at least one processor is further configured to:

receive, from the first UE, an indication that the UE is no longer operating in accordance with the low-mobility mode;

select a second set of beams on the uplink channel, a number of beams in the second set of uplink beams being less than the number of beams in the first set of uplink beams; and

transmit an indication of the second set of uplink beams to the first UE.
The base station of claim 24, wherein the at least one processor is further configured to:

determine that a second UE is associated with a mobility that is higher than a mobility associated with the low-mobility mode;

select a second set of beams on the uplink channel, a number of beams in the second set of uplink beams being less than the number of beams in the first set of uplink beams based in part on the determining; and

transmit an indication of the second set of uplink beams to the second UE.