Method, apparatus and medium for reporting and transmitting beams of interest for location estimation

Abstract

The present invention relates to a method, apparatus and medium for reporting and transmitting beams of interest for location estimation, comprising: receiving, at a base station, a plurality of beams from a user equipment (UE); determining, by the base station, a time of arrival for each of the plurality of beams; identifying, by the base station, one or more beams of interest from the plurality of beams for determining a location estimate of the base station based on the time of arrival of the plurality of beams; transmitting, by the base station to the UE, a report identifying each of one or more beams of interest, each of the plurality of beams carrying a synchronization signal of the UE; receiving, after transmitting the report, at least one additional beam other than the one or more beams of interest, or receiving at least one additional beam rather than the one or more beams of interest, the at least one additional beam carrying a positioning reference signal of the UE, the base station receiving the at least one additional beam from a direction of the one or more beams of interest; each of the one or more beams of interest has an earlier time of arrival at the base station than the remaining beams of the plurality of beams.

Description

[0001] This application is a divisional application of the invention patent application with application number 201980034265.4 filed on May 21, 2019 and invention name “Identifying and reporting beams of interest for position estimation”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This patent application claims the benefit of U.S. Provisional Application No. 62 / 676,272, filed on May 24, 2018, entitled “IDENTIFYING AND REPORTING BEAMS OF INTERESTATION FOR POSITION ESTIMATION,” and U.S. Non-Provisional Application No. 16 / 417,343, filed on May 20, 2019, entitled “IDENTIFYING AND REPORTING BEAMS OF INTEREST FOR POSITION ESTIMATION,” both of which are assigned to the assignee herein and are expressly incorporated herein by reference in their entirety. Technical Field

[0004] Various aspects described herein relate generally to wireless communication systems and, more particularly, to identifying and reporting beams of interest for position estimation. Background Art

[0005] Wireless communication systems have evolved through various generations, including first generation analog wireless telephone service (1G), second generation (2G) digital wireless telephone service (including interim 2.5G and 2.75G networks), third generation (3G) high speed data, Internet-enabled wireless services, and fourth generation (4G) services (e.g., Long Term Evolution (LTE) or WiMax). There are many different types of wireless communication systems in use today, 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), Global System for Mobile Access (GSM) variants of TDMA, and the like.

[0006] The fifth generation (5G) mobile communication standard requires improvements such as higher data transmission speeds, a greater number of connections, and better coverage. According to the Next Generation Mobile Networks Alliance, the 5G standard aims to provide data rates of tens of megabits per second for each of tens of thousands of users and 1 gigabit per second for dozens of workers on an office floor. In order to support the deployment of large sensors, hundreds of thousands of simultaneous connections should be supported. Therefore, the spectrum efficiency of 5G mobile communications should be significantly improved compared to the current 4G standard. In addition, signaling efficiency should be improved and latency should be significantly reduced compared to the current standard.

[0007] Some wireless communication networks, such as 5G, support operation in very high or even extremely high frequency (EHF) bands, such as the millimeter wave (mmW) band (generally, 1 mm to 10 mm wavelength, or 30 to 300 gigahertz (GHz)). These extremely high frequencies can support very high throughputs, such as up to 6 gigabits per second (Gbps). However, one of the challenges of wireless communication at very high or extremely high frequencies is that significant propagation losses can occur due to the high frequencies. As the frequency increases, the wavelength can decrease, and the propagation losses can also increase. In the mmW bands, the propagation losses can be severe. For example, the propagation losses can be on the order of 22 to 27 decibels (dB) relative to the propagation losses observed in the 2.4 GHz or 5 GHz bands.

[0008] In multiple-input multiple-output (MIMO) and large-scale MIMO systems of any frequency band, propagation loss is also a problem. The term MIMO used herein generally refers to both MIMO and large-scale MIMO. MIMO is a method of multiplying the capacity of a radio link by using multiple transmitting and receiving antennas to utilize multipath propagation. Multipath propagation occurs because radio frequency (RF) signals not only travel through the shortest path between the transmitter and the receiver (which may be a line-of-sight (LOS) path), but also travel through multiple other paths because they diffuse out from the transmitter and reflect away from other objects (such as mountains, buildings, water, etc.) on their way to the receiver. The transmitter in the MIMO system includes multiple antennas and utilizes multipath propagation by guiding these antennas so that each antenna sends the same RF signal to the receiver on the same radio channel. The receiver is also equipped with multiple antennas that are tuned to the radio channel that can detect the RF signal sent by the transmitter. When the RF signal arrives at the receiver (due to multipath propagation, some RF signals may be delayed), the receiver can merge them into a single RF signal. Propagation losses are also a problem in MIMO systems because the transmitter transmits each RF signal at a lower power level than it would transmit a single RF signal.

[0009] To address the propagation loss problem in mmW band systems and MIMO systems, the transmitter can use beamforming to extend the coverage of the RF signal. In particular, transmit beamforming is a technique for transmitting RF signals in a specific direction, while receive beamforming is a technique for improving the receive sensitivity of RF signals that arrive at the receiver along a specific direction. Transmit beamforming and receive beamforming can be used in conjunction with each other or separately, and depending on the context, references to "beamforming" hereinafter may refer to transmit beamforming, receive beamforming, or both. Traditionally, when a transmitter broadcasts an RF signal, it broadcasts the RF signal in almost all directions determined by a fixed antenna pattern or the radiation pattern of the antenna. Using 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 the receiver with a faster (in terms of data rate) and stronger RF signal. In order to change the directionality of the RF signal when transmitting, the transmitter can control the phase and relative amplitude of the RF signal broadcast by each antenna. For example, a transmitter may use an array of antennas (also called a "phased array" or "antenna array") that create a beam of RF waves that can be "steered" to point in different directions without actually moving the antennas. Specifically, RF currents are fed to a single antenna with the correct phase relationship so that the radio waves from the separate antennas add together to increase radiation in the desired direction, while canceling the radio waves from the separate antennas to suppress radiation in undesired directions.

[0010] To support position estimation in terrestrial wireless networks, mobile devices can be configured to measure and report observed time difference of arrival (OTDOA) or reference signal timing difference (RSTD) between reference RF signals received from two or more network nodes (e.g., different base stations or different transmission points (e.g., antennas) belonging to the same base station).

[0011] In the case where a transmitter transmits an RF signal using beamforming, the beam of interest for data communication between the transmitter and the receiver will generally be the beam that carries the RF signal with the highest received signal strength (or the highest received signal-to-interference-plus-noise ratio (SINR), e.g., in the presence of a directional interfering signal) at the receiver. However, when a receiver relies on the beam with the highest received signal strength, the ability of the receiver to perform certain tasks may be compromised. For example, in the case where the beam with the highest received signal strength travels through a NLOS path that is longer than the shortest path (i.e., a LOS path or a shortest non-LOS (NLOS) path), the RF signal may arrive later than an RF signal received through the shortest path due to propagation delays. Therefore, if the receiver is performing a task that requires precise timing measurements (e.g., positioning measurements), and the beam with the highest received signal strength is affected by longer propagation delays, then the beam with the highest received signal strength may not be optimal for the upcoming task. Summary of the invention

[0012] A simplified summary of one or more aspects disclosed herein is presented below. Thus, the following summary should not be considered an extensive overview of all contemplated aspects, nor should the following summary be considered to identify key or critical elements related to all contemplated aspects or to delineate the scope associated with any particular aspect. Therefore, the following summary has the sole purpose of presenting certain concepts related to one or more aspects related to the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0013] In one aspect, a method for reporting beams of interest for position estimation includes: receiving multiple beams from a second node at a first node; determining, by the first node, an arrival time of each of the multiple beams; identifying, by the first node, one or more beams of interest from the multiple beams for determining a position estimate of the first node based on the arrival times of the multiple beams; and sending, by the first node to the second node, a report identifying each of the one or more beams of interest.

[0014] In one aspect, a method for sending a beam of interest for position estimation includes: sending a plurality of beams by a second node to a first node; receiving, at the second node, a report from the first node identifying one or more beams of interest for determining a position estimate of the first node, wherein the one or more beams of interest are a subset of the plurality of beams; and sending, by the second node in response to receiving the report, at least one beam carrying a position reference signal of the second node in the same direction as the direction of the one or more beams of interest.

[0015] In one aspect, an apparatus for reporting beams of interest for position estimation includes: a transceiver of a first node configured to receive a plurality of beams from a second node; and at least one processor of the first node configured to: determine an arrival time of each of the plurality of beams, identify one or more beams of interest from the plurality of beams for determining a position estimate of the first node based on the arrival times of the plurality of beams, and cause the transceiver to send a report identifying each of the one or more beams of interest to the second node.

[0016] In one aspect, an apparatus for transmitting beams of interest for a position estimate comprises: a transmitter of a second node configured to transmit a plurality of beams to a first node; and a receiver of the second node configured to receive a report from the first node identifying one or more beams of interest for determining a position estimate of the first node, wherein the one or more beams of interest are a subset of the plurality of beams; wherein the transmitter is further configured to, in response to receipt of the report, transmit to the first node at least one beam carrying a position reference signal of the second node in the same direction as the direction of the one or more beams of interest.

[0017] In one aspect, an apparatus for reporting beams of interest for position estimation includes: a receiving component for a first node, configured to receive multiple beams from a second node; and a processing component for the first node, configured to: determine an arrival time of each of the multiple beams, and identify one or more beams of interest from the multiple beams for determining a position estimate of the first node based on the arrival times of the multiple beams; and a sending component for the first node, configured to send a report identifying each of the one or more beams of interest to the second node.

[0018] In one aspect, an apparatus for sending beams of interest for position estimation comprises: a sending component for a second node, configured to send multiple beams to a first node; and a receiving component for the second node, configured to receive a report from the first node identifying one or more beams of interest for determining a position estimate of the first node, wherein the one or more beams of interest are a subset of the multiple beams; wherein the sending component is further configured to, in response to receiving the report, send at least one beam carrying a position reference signal of the second node to the first node in the same direction as the direction of the one or more beams of interest.

[0019] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions for reporting beams of interest for position estimation includes computer-executable instructions including: at least one instruction instructing a first node to receive multiple beams from a second node; at least one instruction instructing the first node to determine an arrival time of each of the multiple beams; at least one instruction instructing the first node to identify one or more beams of interest from the multiple beams for determining a position estimate of the first node based on the arrival times of the multiple beams; and at least one instruction instructing the first node to send a report identifying each of the one or more beams of interest to the second node.

[0020] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions for sending beams of interest for position estimation includes computer-executable instructions comprising: at least one instruction instructing a second node to send multiple beams to a first node; at least one instruction instructing the second node to receive a report from the first node identifying one or more beams of interest for determining a position estimate of the first node, wherein the one or more beams of interest are a subset of the multiple beams; and at least one instruction instructing the second node to send at least one beam carrying a position reference signal of the second node to the first node in a direction same as the direction of the one or more beams of interest in response to receiving the report.

[0021] Other objects and advantages associated with the various aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] A more complete appreciation of the various aspects described herein and many of their attendant advantages will be readily obtained and better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, which are presented for purposes of illustration only and not limitation, wherein:

[0023] Figure 1

[0013] An exemplary wireless communication system in accordance with various aspects is shown.

[0024] Figure 2A and 2B Example wireless network structures in accordance with various aspects are shown.

[0025] Figure 3 An exemplary base station and an exemplary user equipment (UE) in an access network according to various aspects are shown.

[0026] Figure 4 An exemplary wireless communication system in accordance with aspects of the present disclosure is shown.

[0027] Figure 5 An exemplary wireless communication system in accordance with aspects of the present disclosure is shown.

[0028] Fig. 6A is a graph illustrating RF channel response at a UE over time in accordance with aspects of the present disclosure.

[0029] Figure 6B An exemplary cluster separation from the angle of departure (AoD) is shown in accordance with aspects of the present disclosure.

[0030] Figure 7-Figure 9 Exemplary methods according to various aspects are shown. DETAILED DESCRIPTION

[0031] Various aspects of the present disclosure are described in the following description and related figures to illustrate specific examples related to exemplary aspects. For those skilled in the relevant art, after reading this disclosure, alternative aspects will be apparent and can be constructed and practiced without departing from the scope or spirit of the present disclosure. In addition, well-known elements will not be described in detail, or may be omitted, so as not to obscure the relevant details of aspects of the present disclosure.

[0032] 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.

[0033] The terms used herein describe specific aspects only and should not be construed as limiting any aspect 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. It will be further understood by those skilled in the art that the terms "include" and / or "comprise" used herein specify the presence of stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groupings thereof.

[0034] In addition, for example, various aspects can be described with a sequence of actions to be performed by elements of a computing device. Those skilled in the art will recognize that the various actions described herein can be performed by a specific circuit (e.g., an application specific integrated circuit (ASIC)), by a program instruction executed by one or more processors, or by a combination of the two. In addition, these action sequences described herein can be considered to be fully embodied in any form of a non-transient computer-readable medium, which has a corresponding computer instruction set stored thereon, which, when executed, will cause the relevant processor to perform the functions described herein. Therefore, the various aspects described herein can be embodied in a plurality of different forms, all of which have been contemplated within the scope of the claimed subject matter. In addition, for example, for each of the aspects described herein, the corresponding form of any of these aspects can be described herein as "logically configured to" and / or configured to perform other structural components of the described actions.

[0035] As used herein, the terms "user equipment" (or "UE"), "user device", "user terminal", "client device", "communication device", "wireless device", "wireless communication device", "handheld device", "mobile device", "mobile terminal", "mobile station", "handset", "access terminal", "subscriber device", "subscriber terminal", "subscriber station", "terminal" and variations thereof are interchangeable to refer to any suitable mobile or fixed device that can receive wireless communication and / or navigation signals. These terms are also intended to include devices that communicate with another device that can receive wireless communication and / or navigation signals (such as through short-range wireless, infrared, wired connection or other connection), regardless of whether satellite signal reception, auxiliary data reception and / or location-related processing occurs at the device or at another device. In addition, these terms are intended to include all devices, including wireless and wired communication devices, that can communicate with a core network via a radio access network (RAN), and through which the UE can be connected to an external network (such as the Internet) and to other UEs. Of course, it is also possible for the UE to be connected to the core network and / or the Internet through other mechanisms, such as through a wired access network, a wireless local area network (WLAN) (e.g., based on IEEE 802.11, etc.), etc. The UE may be embodied by any of a number of types of devices including, but not limited to, a printed circuit (PC) card, a compact flash device, an external or internal modem, a wireless or wired phone, a smartphone, a tablet, a tracking device, an asset tag, etc. The communication link through which the UE may send signals to the RAN is referred to as an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). The communication link through which the RAN may send signals to the UE is referred to as a downlink or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). The term traffic channel (TCH) as used herein may refer to an uplink / reverse or downlink / forward traffic channel.

[0036] According to various aspects, Figure 1 An exemplary wireless communication system 100 is shown. The wireless communication 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), wherein the wireless communication system 100 corresponds to an LTE network, or gNodeBs (gNBs), wherein the wireless communication system 100 corresponds to a 5G network, or a combination of the two, and the small cells may include femto cells, pico cells, micro cells, etc.

[0037] The base stations 102 may collectively form a RAN and interface with an evolved packet core (EPC) or a next generation core (NGC) via a backhaul link. In addition to other functions, the base stations 102 may also perform functions related to one or more of the following: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via EPC / NGC) via a backhaul link 134, which may be wired or wireless.

[0038] Base stations 102 can wirelessly communicate with UEs 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. In one aspect, although Figure 1 Although not shown in the drawings, geographic coverage area 110 may be subdivided into multiple cells (e.g., three) or sectors, each cell corresponding to a single antenna or antenna array of base station 102. As used herein, the term "cell" or "sector" may correspond to one of the multiple cells of base station 102, or to base station 102 itself, depending on the context.

[0039] Although adjacent macrocell 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 macrocell base stations 102. A network including small cells and macrocells is known as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB), which may provide services to a restricted group known as a closed subscriber group (CSG). The communication link 120 between the base station 102 and the UE 104 may include an uplink (UL) (also known as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also known as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be through one or more carriers. The allocation of carriers may be asymmetric for DL ​​and UL (eg, more or fewer carriers may be allocated to DL than to UL).

[0040] The wireless communication system 100 may also include a wireless local area network (WLAN) access point (AP) 150 that communicates with a WLAN station (STA) 152 via a communication link 154 in an unlicensed spectrum (e.g., 5 GHz). When communicating in the unlicensed spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether a channel is available.

[0041] The small cell base station 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell base station 102' can adopt LTE or 5G technology and use the same 5 GHz unlicensed spectrum used by the WLAN AP 150. The small cell base station 102' adopting LTE / 5G in the unlicensed spectrum can improve the coverage of the access network and / or increase the capacity of the access network. LTE in the unlicensed spectrum can be referred to as LTE-Unlicensed (LTE-U), Licensed Assisted Access (LAA), or

[0042] Extremely high frequency (EHF) is part of RF in the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz, and has a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near mmW may extend down to a frequency of 3 GHz, with a wavelength of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also known as centimeter waves. Communications using mmW / near mmW radio frequency bands have high path loss and relatively short distances. The wireless communication system 100 may also include a mmW base station 180, which may operate at mmW frequencies and / or near mmW frequencies, communicating with UE 182. The mmW base station 180 may utilize beamforming 184 with UE 182 to compensate for extremely high path loss and short range. In addition, it will be understood that in an alternative configuration, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Therefore, it will be understood that the foregoing illustrations are merely examples and should not be interpreted as limiting the various aspects disclosed herein.

[0043] The wireless communication system 100 may also include one or more UEs, such as UE 190, which are indirectly connected to one or more communication networks via one or more device-to-device (D2D), peer-to-peer (P2P) links. Figure 1 In the example of FIG. 1 , UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of base stations 102 (e.g., through which UE 190 can indirectly obtain a cellular connection) and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which UE 190 can indirectly obtain a WLAN-based Internet connection). In the example, any well-known D2D radio access technology (RAT) (such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), etc.) support D2D P2P links 192-194.

[0044] According to various aspects, Figure 2AAn example wireless network architecture 200 is shown. For example, the NGC 210 can be functionally viewed as a control plane function 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane function 212 (e.g., UE gateway function, access data network, Internet Protocol (IP) routing, etc.), which operate in cooperation to form a core network. The user plane interface (NG-U) 213 and the control plane interface (NG-C) 215 connect the gNB 222 to the NGC 210, and specifically to the control plane function 214 and the user plane function 212. In another configuration, the eNB 224 can also be connected to the NGC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. In addition, the eNB 224 can communicate directly with the gNB 222 via the backhaul connection 223. Thus, in some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either the gNB 222 or the eNB 224 may communicate with a UE 240 (e.g., Figure 1 2, such as UE 104, UE 152, UE 182, UE 190, etc.). Another optional aspect may include a location server 230, which may communicate with the NGC 210 to provide location assistance for the UE 240. The location server 230 may be implemented as a plurality of structurally separate servers, or alternatively may each correspond to a single server. The location server 230 may be configured to support one or more location services for the UE 240, which may be connected to the location server 230 via the core network, the NGC 210, and / or via the Internet (not shown). In addition, the location server 230 may be integrated into a component of the core network, or alternatively may be external to the core network.

[0045] According to various aspects, Figure 2BAnother example wireless network architecture 250 is shown. For example, the EPC 260 can be functionally viewed as a control plane function, a mobility management entity (MME) 264 and a user plane function, a packet data network gateway / serving gateway (P / SGW) 262, which operate in cooperation to form a core network. The S1 user plane interface (S1-U) 263 and the S1 control plane interface (S1-MME) 265 connect the eNB 224 to the EPC 260, and specifically to the MME 264 and the P / SGW 262. In another configuration, the gNB 222 can also be connected to the EPC 260 via the S1-MME 265 to the MME 264 and the S1-U 263 to the P / SGW 262. In addition, the eNB 224 can communicate directly with the gNB 222 via the backhaul connection 223, with or without a gNB direct connection to the EPC 260. Thus, in some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either the gNB 222 or the eNB 224 may communicate with the UE 240 (e.g., Figure 1 240, such as UE 104, UE 152, UE 182, UE 190, etc.). Another optional aspect may include a location server 230, which may communicate with EPC 260 to provide location assistance for UE 240. Location server 230 may be implemented as multiple structurally separate servers, or alternatively may each correspond to a single server. Location server 230 may be configured to support one or more location services for UE 240, which may be connected to location server 230 via a core network, EPC 260, and / or via the Internet (not shown).

[0046] According to various aspects, Figure 3 An exemplary base station 310 (e.g., eNB, gNB, small cell AP, WLAN AP, etc.) and an exemplary UE 350 (e.g., Figure 1104, UE 152, UE 182, UE 190, etc.). In the DL, IP packets from the core network (NGC 210 / EPC 260) may be provided to the controller / processor 375. The controller / processor 375 implements the functions of 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 functions, which are associated with broadcasting of system information (e.g., master information block (MIB), system information block (SIB)), 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 functions, which are associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functions, which are associated with delivery 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 functions, which are associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0047] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be split into parallel streams. Each stream can 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 generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived from reference signals and / or channel condition feedback sent by the UE 350. Each spatial stream may then be provided to one or more different antennas 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0048] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX 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 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams intended for the UE 350. If multiple spatial streams are intended for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point sent by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0049] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a non-transitory computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the core network. The controller / processor 359 is also responsible for error detection.

[0050] Similar to the functions described in conjunction with the DL transmission of the base station 310, the controller / processor 359 provides: RRC layer functions, which are associated with system information (e.g., MIB, SIB) acquisition, RRC connection and measurement reporting; PDCP layer functions, which are associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions, which are associated with the delivery 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 functions, which are 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.

[0051] 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 antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier having a corresponding spatial stream for transmission.

[0052] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0053] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a non-transitory computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the core network. The controller / processor 375 is also responsible for error detection.

[0054] Figure 4An exemplary wireless communication system 400 is shown in accordance with aspects of the present disclosure. Figure 4 In the example of , it may correspond to any one of the above UEs (for example, Figure 1 UE 104, UE 152, UE 182, UE 190, etc., Figure 2A and Figure 2B UE 240 in the Figure 3 UE 404 (any one of UE 350 in FIG. 1 ) is attempting to calculate its location estimate, or assist another entity (e.g., a base station or core network component, another UE, a location server, a third-party application, etc.) in calculating its location estimate. UE 404 can communicate wirelessly with multiple base stations 402a-d (collectively referred to as base stations 402), which can correspond to Figure 1 The base station 102 or 180 and / or the WLAN AP 150 in Figure 2A and Figure 2B eNB 224 or gNB 222 or Figure 3 Any combination of base stations 310 in the wireless communication system 400 uses RF signals and standardized protocols for modulation of the RF signals and exchange of information packets. By extracting different types of information from the exchanged RF signals and utilizing the layout of the wireless communication system 400 (i.e., the location, geometry, etc. of the base stations 402), the UE 404 can determine its position in a predefined reference coordinate system, or assist in determining its position. In one aspect, the UE 404 can 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 position using a three-dimensional coordinate system if additional dimensions are desired. In addition, although Figure 4 One UE 404 and four base stations 402 are shown, but as will be understood, there may be more UEs 404 and more or fewer base stations 402.

[0055] 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 location of the antenna of the base station 402 is different from the location of the base station 402 itself), or any other network entity capable of sending a reference RF signal. In addition, as used herein, a "node" may refer to a network node or a UE.

[0056] The term "base station" may refer to a single physical transmission point or to multiple physical transmission points, which may be co-located or not 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 a 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 point may be an antenna array of a base station (e.g., as in a MIMO system or where the base station employs beamforming). Where the term "base station" refers to multiple non-co-located physical transmission points, the physical transmission point may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transmission 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 a serving base station that receives a measurement report from a UE (e.g., UE 404) and a neighboring base station whose reference RF signal the UE is measuring. Thus, Figure 4 An aspect is shown in which base stations 402a and 402b form a DAS / RRH 420. For example, base station 402a may be a serving base station for UE 404, and base station 402b may be a neighboring base station for UE 404. Thus, base station 402b may be an RRH for base station 402a. Base stations 402a and 402b may communicate with each other via a wired or wireless link 422.

[0057] A location server (e.g., location server 230) may send assistance data to UE 404, the assistance data including identification of one or more neighboring cells of base station 402 and configuration information of reference RF signals transmitted by each neighboring cell. Alternatively, the assistance data may originate directly from base station 402 itself (e.g., in a periodically broadcast overhead message, etc.). Alternatively, UE 404 may detect neighboring cells of base station 402 by itself without using assistance data. As further described herein, UE 404 (e.g., based in part on assistance data (if provided)) may measure and (optionally) report the RTT between itself and various network nodes. Using these measurements and the known locations of the measured network nodes (i.e., the (multiple) base stations 402 or (multiple) antennas that transmit the reference RF signals measured by UE 404), UE 404 or a location server may determine the distance between UE 404 and the measured network nodes, thereby calculating the location of UE 404.

[0058] The term "position estimate" is used herein to refer to an estimate of the location of a UE (e.g., UE 404), which may be geographic (e.g., may include latitude, longitude, and possibly altitude) or civic (e.g., may include a street address, a building name, or a precise point or area within or near a building or street address, such as a specific entrance to a building, a specific room or suite in a building, or a landmark such as a city square). A position estimate may also be referred to as a "position," "location," "fix," "position fix," "location fix," "position estimate," "fix estimate," or other terms. Methods of obtaining a position estimate may generally be referred to as "positioning," "locating," or "location fix." A specific scheme for obtaining a position estimate may be referred to as a "position solution." As part of a position solution, a specific method for obtaining a position estimate may be referred to as, for example, a "position method" or a "positioning method." A position estimate may include expected errors or uncertainties (e.g., by including an area or volume in which the position is expected to be included with some specified or default confidence level).

[0059] To support position estimation, the base station 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), narrowband reference signals (NRS), synchronization signals, etc.) to the UEs 404 within its coverage area to enable the UEs 404 to measure the RTT between the UEs 404 and the transmitting base station 402. In general, the beam of interest for RTT measurement is the LOS beam, or the beam that excites the shortest RF path (which may be a LOS beam or a NLOS beam that follows the shortest path to the receiver).

[0060] However, RF signals travel not only through the LOS / shortest NLOS path between the transmitter and the receiver, but also through multiple other paths as the RF signals spread out from the transmitter and reflect off other objects (such as mountains, buildings, water, etc.) on their way to the receiver. Figure 4 Multiple LOS paths 410 and multiple NLOS paths 412 between base station 402 and UE 404 are shown. Specifically, Figure 4 Base station 402a is shown transmitting via LOS path 410a and NLOS path 412a, base station 402b is shown transmitting via LOS path 410b and two NLOS paths 412b, base station 402c is shown transmitting via LOS path 410c and NLOS path 412c, and base station 402d is shown transmitting via two NLOS paths 412d. Figure 4 , each NLOS path 412 is reflected off of some object 430 (e.g., a building). As will be appreciated, each LOS path 410 and NLOS path 412 transmitted by base station 402 may be transmitted by a different antenna of base station 402 (e.g., as in a MIMO system), or may be transmitted by the same antenna of base station 402 (thereby illustrating the propagation of RF signals). Furthermore, as used herein, the term "LOS path" refers to the shortest path between a transmitter and a receiver, and may not be the actual LOS path, but rather the shortest NLOS path.

[0061] In one aspect, one or more base stations 402 may be configured to transmit RF signals using beamforming. In that case, some of the available beams may focus the transmitted RF signals along the LOS path 410 (e.g., the beams produce the highest antenna gain along the LOS path), while other available beams may focus the transmitted RF signals along the NLOS path 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 the RF signal naturally depends on the beam gain along those other paths. An "RF signal" includes electromagnetic waves that transmit information through the space between a transmitter and a receiver. As used herein, a transmitter may send a single "RF signal" or multiple "RF signals" to a receiver. However, as further described below, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal.

[0062] In the case where the base station 402 uses beamforming to transmit RF signals, the beam of interest for data communication between the base station 402 and the UE 404 will be the beam carrying the RF signal that reaches the UE 404 with the highest signal strength (e.g., indicated by the received signal received power (RSRP) or SINR in the presence of a directional interfering signal), while the beam of interest for position estimation will be the beam carrying the RF signal that excites the shortest path or LOS path (e.g., LOS path 410). In some frequency bands and for commonly used antenna systems, these will be the same beam. However, in other frequency bands, such as mmW, where a large number of antenna elements can be used to create a narrow transmit beam, they may not be the same beam. That is, in some cases, the signal strength of the RF signal on the LOS path 410 may be weaker (e.g., due to obstacles) than the signal strength of the RF signal on the NLOS path 412, where the RF signal arrives later due to propagation delays.

[0063] Figure 5An exemplary wireless communication system 500 is shown in accordance with aspects of the present disclosure. Figure 5 In the example, it may correspond to any one of the UEs described above (for example, Figure 1 UE 104, UE 152, UE 182, UE 190, etc., Figure 2A and Figure 2B UE 240 in Figure 3 UE 350 in , and Figure 4 UE 504 (e.g., any one of UE 404 in ) is attempting to calculate its location estimate, or assist another entity (e.g., a base station or core network component, another UE, a location server, a third-party application, etc.) in calculating its location estimate. UE 504 can wirelessly communicate with base station 502, which can correspond to any of the base stations described above (e.g., Figure 1 The base station 102 or 180 and / or the WLAN AP 150 in Figure 2A and Figure 2B eNB 224 or gNB 222 in Figure 3 Base station 310, or Figure 4 any one of the base stations 402 in the communication network), using RF signals and standardized protocols for modulation of the RF signals and exchange of information packets.

[0064] like Figure 5 As shown in FIG. 5 , base station 502 is utilizing beamforming to transmit multiple beams 511-515 of RF signals. Each beam 511-515 may be formed and transmitted by an antenna array of base station 502. Figure 5 A base station 502 is shown transmitting five beams, but as will be understood, there may be more or fewer than five beams, the beam shapes (such as peak gain, width, and sidelobe gain) may differ among the transmitted beams, and some of the beams may be transmitted by different base stations.

[0065] For the purpose of distinguishing an RF signal associated with one beam from an RF signal associated with another beam, a beam index may be assigned to each of the plurality of beams 511-515. In addition, an RF signal associated with a particular beam of the plurality of beams 511-515 may carry a beam index indicator. The beam index may also be derived from the transmission time (e.g., frame, time slot, and / or OFDM symbol number) of the RF signal. For example, the beam index indicator may be a 3-bit field for uniquely distinguishing up to 8 beams. If two different RF signals with different beam indices are received, this would indicate that the RF signals are 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 is quasi-collocated spatially with the antenna port(s) used for the transmission of the second RF signal.

[0066] exist Figure 5 In the example of FIG. 5 , UE 504 receives NLOS data stream 523 of the RF signal transmitted on beam 513 and LOS data stream 524 of the RF signal transmitted on beam 514. Figure 5 NLOS data stream 523 and LOS data stream 524 are illustrated as single lines (dashed and solid, respectively), but as will be appreciated, due to the propagation characteristics of RF signals through multipath channels (e.g.), NLOS data stream 523 and LOS data stream 524 may each contain multiple rays (i.e., "clusters") before they reach UE 504. For example, RF signal clusters are formed when electromagnetic waves reflect off multiple surfaces of an object, and the reflections arrive at a receiver (e.g., UE 504) from approximately the same angle, with each reflection traveling a few wavelengths (e.g., centimeters) more or less than the other reflections. A "cluster" of received RF signals generally corresponds to a single transmitted RF signal.

[0067] exist Figure 5 In the example of FIG. 5 , NLOS data stream 523 is not initially directed to UE 504, although as will be appreciated, it may be so. Figure 44. However, it reflects off of reflector 540 (e.g., a building) and arrives at UE 504 without obstacles, and therefore, may still be a relatively strong RF signal. In contrast, LOS data stream 524 is directed toward UE 504 but passes through obstacles 530 (e.g., vegetation, buildings, hills, interfering environments (such as clouds or smoke), etc.), which can significantly reduce the RF signal. As will be appreciated, although LOS data stream 524 is weaker than NLOS data stream 523, because LOS data stream 524 follows a shorter path from base station 502 to UE 504, it will arrive at UE 504 before NLOS data stream 523.

[0068] As described above, the beam of interest for data communication between a transmitter (e.g., base station 502) and a receiver (e.g., UE 504) is the beam carrying the RF signal that reaches the receiver with the highest signal strength (e.g., the highest RSRP or SINR), while the beam of interest for position estimation is the beam carrying the RF signal that excites the LOS path and has the highest gain along the LOS path among all other beams (e.g., beam 514). That is, even if beam 513 (NLOS beam) excites the LOS path weakly (even if not focused along the LOS path due to the propagation characteristics of the RF signal), this weak signal (if any) of the LOS path of beam 513 may not be reliably detectable (compared to the signal from beam 514), thus resulting in a larger error in performing positioning measurements.

[0069] While the beam of interest for data communication and the beam of interest for position estimation may generally be the same beam for some frequency bands, for other frequency bands, such as mmW, they may not be the same beam. Figure 5 , in the case where UE 504 is engaged in a data communication session with base station 502 (e.g., base station 502 is the serving base station for UE 504), rather than simply attempting to measure the reference RF signal transmitted by base station 502, the beam of interest for the data communication session may be beam 513 because it carries the unobstructed NLOS data stream 523. However, the beam of interest for position estimation would be beam 514 because it carries the strongest LOS data stream 524 despite being blocked.

[0070] Fig. 6A 600A is a diagram illustrating RF channel response at a receiver (eg, UE 504) over time in accordance with aspects of the present disclosure. Fig. 6A, the receiver detects a first cluster of two channel taps at time T1, a second cluster of five channel taps at time T2, a third cluster of five channel taps at time T3, and a fourth cluster of four channel taps at time T4. The cluster of channel taps is the first detectable occurrence of the received RF signal / data stream.

[0071] exist Fig. 6A In the example of , because the first cluster of channel taps is the first detected at time T1, it is assumed that the corresponding data stream is a LOS data stream (i.e., a data stream that arrives via LOS or the shortest path), and may correspond to Figure 5 The third cluster at time T3 contains the strongest channel taps and may correspond to Figure 5 NLOS data stream 523 in FIG. From the transmitter side, each cluster of channel taps may correspond to a portion of the RF signal transmitted at a different angle, and thus each cluster may be said to have a different angle of departure (AoD) from the transmitter. Note that although Fig. 6A Clusters of two to five channel taps are shown, but as will be understood, the clusters may have a single channel tap or more than five detected channel taps.

[0072] Figure 6B 600B is a diagram illustrating the separation of clusters from the perspective of AoD according to aspects of the present disclosure. The RF signal transmitted by the transmitter in the AoD range 602a may be a first cluster (e.g., Fig. 6A 1 ) is received at the receiver, and the RF signal transmitted by the transmitter in AoD range 602 b may be received as a different cluster (e.g., Fig. 6A 6b) are received at the receiver. Note that, although the AoD ranges depicted in FIG6b are spatially isolated, the AoD ranges corresponding to some received clusters may also partially overlap, even if the clusters are separated in time. This may occur, for example, when an RF signal is reflected from a transmitter toward a receiver with the same AoD from two separate buildings.

[0073] Continue to refer Figure 6B , as in Figure 5 In the example of FIG. 6 , the transmitter may utilize beamforming to transmit multiple beams of RF signals such that one of the beams (eg, beam 514) is directed toward AoD range 602a, corresponding to Fig. 6A , and a different beam (e.g., beam 513) is directed to AoD range 602b, corresponding to Fig. 6AIn the channel response after beamforming (i.e., the channel response when the transmitted RF signal is beamformed rather than omnidirectional), the signal strength of the cluster will be scaled by the beam gain along the AoD corresponding to the cluster. In that case, the beams of interest for positioning will be the beams positioned at the AoDs corresponding to the first cluster of channel taps, because they arrive first, and the beams of interest for data communication may be the beams positioned at the AoDs corresponding to the third cluster of channel taps, because they are the strongest.

[0074] In general, when transmitting an RF signal, the transmitter (e.g., base station 502) does not know what path it will follow to reach the receiver (e.g., UE 504) or at what time it will arrive at the receiver, and therefore transmits the RF signal on different antenna ports with equal amounts of energy. Alternatively, the transmitter may beamform the RF signal in different directions over multiple transmit opportunities and obtain measurement feedback from the receiver to determine the radio path explicitly or implicitly.

[0075] Note that while the techniques disclosed herein are generally described in terms of transmissions from a base station to a UE, as will be appreciated, they 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 the context of transmit beamforming, in some aspects, receive beamforming may also be used in conjunction with the transmit beamforming described above.

[0076] As discussed above, in some frequency bands, the shortest path (which, as discussed above, may be a LOS path or the shortest NLOS path) may be weaker than an alternative longer (NLOS) path (on which the RF signal arrives later due to propagation delays). Therefore, where a transmitter transmits RF signals using beamforming, the beam of interest for data communication—the beam carrying the strongest RF signal—may be different from the beam of interest for position estimation—the beam carrying the RF signal that excites the shortest detectable path. Therefore, in one aspect, it would be advantageous for a receiver to identify and report to the transmitter the beam of interest for position estimation so that the transmitter can subsequently modify the set of transmit beams to assist the receiver in performing position estimation.

[0077] Figure 7 1 shows an exemplary method according to various aspects of the present disclosure. At 702, a second node 703 (referred to as a "transmitter") transmits a set of beams 705, 707, and 709 to a first node 701 (referred to as a "receiver"). In one aspect, the first node 701 may correspond to any of the above-mentioned UEs (such as Figure 1 UE 104, UE 152, UE 182, UE 190, etc., Figure 2A and Figure 2B UE 240 in Figure 3 UE 350, Figure 4 UE 404 and Figure 5 ), and the second node 703 may correspond to any one of the above-mentioned base stations (such as Figure 1 Base station 102 or 180 and / or WLAN AP 150, Figure 2A and 2B eNB 224 or gNB 222 in Figure 3 The base station 310 in Figure 4 Base station 402 and Figure 5 However, in one aspect, the first node 701 may be a base station, the second node 703 may be a UE, or both the first node 701 and the second node 703 may be a UE or a base station. As another option, the second node 703 may be a single antenna or antenna array of a base station or UE capable of beamforming.

[0078] exist Figure 7 In the example of FIG. 7 , the second node 703 transmits a set of three beams 705, 707, and 709. These beams may be transmitted simultaneously but may be distinguished in the frequency domain and / or code domain. Alternatively, these beams may be transmitted sequentially. The second node 703 may transmit beams 705, 707, and 709 at different AoDs, as described above. Figure 5 and Figure 6B As shown. Figure 7 In the example of FIG. 7 , beam 707 (shown as a straight line) may follow the shortest path (e.g., a LOS path or a shortest NLOS path when the LOS path cannot be detected due to an obstacle) from the second node 703 to the first node 701, and beams 705 and 709 may follow a longer (e.g., NLOS) path from the second node 703 to the first node 701. As will be appreciated, as described above, Figure 4 and Figure 5 As shown in the example of , there may be more or fewer than three beams. In one aspect, beams 705, 707, and 709 may carry synchronization signals, such as synchronization signals (SS) or PBCH blocks, CSI reference signals, positioning reference signals, cell reference signals, sounding reference signals, random access preambles, etc.

[0079] At 704, the first node 701 receives beams 705, 707, and 709. At 706, the first node 701 determines the arrival time of each beam 705, 707, and 709. In one aspect, the first node 701 may determine the arrival time of the beam as the time at which the first node 701 detects the first (or earliest) channel tap of the radio channel between the nodes, where the channel is estimated from the received RF signal of the beam 705, 707, or 709. For example, the first node 701 may correlate the received signal of the beam with (the conjugate of) the known transmitted RF signal and determine the channel tap from the associated peaks. The first node 701 may further estimate the noise and eliminate the channel taps that are less reliable than the background noise. The first node 701 may further employ techniques to eliminate false side peaks around strong channel taps, where it is well known that the false side peaks are generated from the band-limited reception of the first node 701. For simplicity, the first channel tap of the RF signal of the beam may also be referred to as the first channel tap of the beam.

[0080] At 708, the first node 701 identifies one or more beams of interest from the set of beams 705, 707, and 709 based on the arrival times determined at 706. As described above, in some frequency bands, where the deployed antenna system does not create sufficiently narrow beams, the beam(s) of interest will be the beam(s) 705, 707, and / or 709 that carry the RF signal with the highest received signal strength (e.g., RSRP or SINR) at the first node 701, as these beams will also be the beam(s) that follow the shortest path to the first node 701. However, as discussed above, in some frequency bands, such as mmW, the beam that carries the RF signal with the highest received signal strength may not be the best beam for positioning operations, as it may not follow the shortest detectable path to the first node 701. Thus, instead of selecting the beam(s) carrying the RF signal with the highest received signal strength, the first node 701 identifies one or more of the earliest arriving beams of beams 705, 707, and 709 as one or more beams of interest.

[0081] For example, one or more beams of interest may be the beams 705, 707, or 709 having the first detected channel tap. Alternatively, one or more beams of interest may be the N (greater than 1, e.g., 2) beams having the earliest detected channel taps. Alternatively, one or more beams of interest may be the beams, or N beams, whose first detected channel taps are within a predetermined time delay (e.g., 10 nanoseconds) of the first detected tap of the beam having the earliest detected first tap. At the speed of light of approximately 0.3 meters per nanosecond (ns), an error or ambiguity in arrival time of 10 nanoseconds corresponds to a positioning / range error of nearly 3 meters. Thus, the delay may be determined by the desired accuracy or the accuracy that can be achieved in the presence of other limiting factors, such as signal pulse width (related to signal bandwidth). The delay parameter may be provided by the first node 701 to the second node 703, or determined by the first node 701 itself and reported to the second node 703. On the one hand, where the first node 701 is a UE, the second node 703 (base station) may command the first node 701 to report the beam of interest for position estimation (rather than the beam with the highest received signal strength as conventionally), the number of beams N to report, and / or a "delay" parameter for selecting the N beams.

[0082] At 710, the first node 701 generates a report containing identifiers (eg, beam indices) of the one or more beams of interest identified at 708. At 712, the first node 701 sends the report to the second node 703.

[0083] At 714, the second node 703 receives the report. Over a wireless interface, the first node 701 may send at 712, and the second node 703 may receive at 714, the report, such as Figure 1 The communication link 120 or D2D P2P link 192 / 194 in the second node 703 receiving the report may or may not be quasi-co-located with the transmission point(s) of the second node 703 from which the beams 705, 707, 709 are transmitted. For example, the reception point of the second node 703 receiving the report may be assigned a cell identifier that is different from the cell identifier of the transmission point of the second node 703 transmitting the beam. The reception point may be a serving cell, while the transmission point may be a non-serving cell, such as a neighboring cell.

[0084] At 716, the second node 703 may select a second set of beams for transmission based on the received report. For example, where the first node 701 is attempting to perform a position estimate and the identified beam(s) are cell synchronization beam(s), the second node 703 may update the beam(s) identified in the report to transmit a positioning RF signal, such as a PRS or CSI-RS. In general, beams that transmit synchronization signals are wider (less focused) than beams that transmit reference RF signals (e.g., CSI-RS). Therefore, on the one hand, the second node 703 may also transmit one or more finer (more focused) beams around the beam(s) identified in the report after they are modified to transmit reference RF signals. More specifically, the second node 703 may narrow the focus of the identified beam(s) and transmit one or more additional narrowly focused beams in the direction of the identified beam(s).

[0085] As another example, also where the first node 701 is attempting to perform a position estimate and the identified beam(s) are cell synchronization beam(s), the second node 703 may transmit one or more beams carrying positioning RF signals in the direction of the beam(s) identified in the report without modifying the beam(s) identified in the report. Thus, in one aspect, the transmission of beams 705, 707, and 709 at 702 may be periodic (e.g., broadcast for the benefit of all UEs served by the second node 703, where the second node 703 is a base station), and the selection of beams at 716 may be for the transmission of specific positioning beacons for the benefit of the first node 701 only, and may be transmitted with a different periodicity or aperiodically.

[0086] In one aspect, where the first node 701 is a base station, then reporting the beam index at 710 and 712 means that the first node 701 requests the second node 703 (e.g., UE) to send further reference beams based on the report. For example, the request may be to send the reported beam again, or to send a finer beam around the reported beam. Thus, the operation at 708 is to shortlist the beam(s) of interest, and then use the beam(s) in the shortlist for continued position estimation, while discarding the "uninteresting" beams.

[0087] At 718, the second node 703 transmits a second set of beams, here beams 711 and 713. As discussed above, beams 711 and 713 may correspond to two of beams 705, 707, and 709 (where the report received at 714 identified two of beams 705, 707, and 709), but modified to transmit reference RF signals (e.g., PRS, CRS). Alternatively, beams 711 and 713 may correspond to one of beams 705, 707, and 709 modified to transmit a reference RF signal, and an additional beam that transmits a reference RF signal in the direction of the beam identified in the report received at 714. In yet another aspect, beams 711 and 713 may be two new beams that transmit reference RF signals in the direction of the beam(s) identified in the report received at 714. In one aspect, at 718, although not shown, prior to transmitting beams 711 and 713, second node 703 may transmit an indication of which beam(s) it has selected for transmission.

[0088] exist Figure 7 In the example of , there are two beams (711 and 713) transmitted at 718. However, as will be understood, this is merely an example, and there may be more or fewer beams transmitted at 718. Figure 7 , beam 711 is shown as following a LOS path, while beam 713 is shown as following a NLOS path (ie, reflected off an object). However, as will be appreciated, both beams 711 and 713 may follow a LOS path, or both may be reflected.

[0089] At 720, the first node 701 receives beams 711 and 713. The first node 701 may perform method 700 with multiple second nodes (including the second node 703) to receive a sufficient number of shortest path beams that can be accurately measured to calculate or assist in the calculation of a position estimate. For example, to perform a single OTDOA measurement, the first node 701 needs to measure reference RF signals from at least two second nodes. The first node 701 may perform multiple OTDOA measurements to improve the accuracy of the position estimate of the first node 701.

[0090] Figure 8An exemplary method 800 for reporting an interest beam according to aspects of the present disclosure is shown. The method 800 may be performed by a first node 805, such as any of the UEs or base stations described above. At 802, the first node 805 (e.g., antenna(s) 320, receiver(s) 318, and / or RX processor 370, or antenna(s) 352, receiver(s) 354, and / or RX processor 356) receives multiple beams (e.g., beams 511-515) from a second node (e.g., any other of the base stations or UEs described above), as at 704. In one aspect, the multiple beams may arrive at the first node from different angles. In one aspect, the first node 805 may receive multiple beams on an EHF (e.g., mmW) band.

[0091] At 804, the first node 805 (e.g., the RX processor 370 and / or the controller / processor 375, or the RX processor 356 and / or the controller / processor 359) determines a time of arrival for each of the plurality of beams, as at 706. In one aspect, receiving the plurality of beams at 802 may include receiving a signal for each of the plurality of beams at the first node 805, and processing the signal to detect a cluster of received signals corresponding to one or more detected channel taps for each of the plurality of beams. In that case, the time of arrival is determined based on the earliest detected channel tap for each of the plurality of beams.

[0092] At 806, the first node 805 (e.g., RX processor 370 and / or controller / processor 375, or RX processor 356 and / or controller / processor 359) identifies one or more beams of interest from the plurality of beams for determining a position estimate of the first node based on the arrival times of the plurality of beams, as at 708. In an aspect, each of the one or more beams of interest may have an earlier arrival time at the first node than the remaining beams in the plurality of beams. In an aspect, each of the one or more beams of interest may have an arrival time before a threshold delay from an earliest arrival time of the beams in the plurality of beams. In an aspect, the one or more beams of interest may be a beam in the plurality of beams that has the earliest arrival time at the first node. In an aspect, at least one beam in the plurality of beams other than the one or more beams of interest may have a higher signal strength than a signal strength of the one or more beams of interest.

[0093] At 808, the first node 805 (e.g., antenna(s) 320, transmitter(s) 318, and / or TX processor 316, or antenna(s) 352, transmitter(s) 354, and / or TX processor 368) sends a report identifying each of the one or more beams of interest to the second node. In an aspect, each beam of the plurality of beams may be associated with a beam index, and the report may identify the one or more beams of interest using the beam index associated with each of the one or more beams of interest.

[0094] In one aspect, each of the plurality of beams may carry a synchronization signal of the second node. In that case, the method 800 may also include, at the first node 805, receiving one or more interest beams after sending the report at 808, wherein, after sending the report, the one or more interest beams are updated to carry the positioning reference signal of the second node instead of the synchronization signal. Additionally or alternatively, the method 800 may also include, at the first node 805, after sending the report at 808, receiving at least one additional beam in addition to the one or more interest beams, wherein the at least one additional beam carries the positioning reference signal of the second node, and wherein the first node receives the at least one additional beam from the direction of the one or more interest beams. Additionally or alternatively, the method 800 may also include, at the first node 805, after sending the report at 808, receiving at least one additional beam instead of the one or more interest beams, wherein the at least one additional beam carries the positioning reference signal of the second node, and wherein the first node receives the at least one additional beam from the direction of the one or more interest beams.

[0095] Fig. 9 An exemplary method 900 for transmitting a beam of interest according to the disclosed aspects is shown. The method 900 may be performed by a second node 905, such as any of the base stations and UEs described above. At 902, the second node 905 (e.g., antenna(s) 320, transmitter(s) 318, and / or TX processor 316, or antenna(s) 352, transmitter(s) 354, and / or TX processor 368) transmits multiple beams (e.g., beams 511-515) to a first node (e.g., any other of the base stations and UEs described above), as at 702. In one aspect, the second node 905 may transmit multiple beams at different angles. In one aspect, the second node 905 may transmit multiple beams on an EHF (e.g., mmW) band.

[0096] At 904, the second node 905 (e.g., antenna(s) 320, receiver(s) 318, and / or RX processor 370, or antenna(s) 352, receiver(s) 354, and / or RX processor 356) receives from the first node a report identifying one or more beams of interest for determining a position estimate of the first node, as at 714, wherein the one or more beams of interest are a subset of the plurality of beams. In an aspect, each of the one or more beams of interest may have an earlier arrival time at the first node than the remaining beams of the plurality of beams. In an aspect, at least one beam of the plurality of beams other than the one or more beams of interest may have a higher signal strength than the signal strength of the one or more beams of interest.

[0097] At 906, the second node 905 (e.g., antenna(s) 320, transmitter(s) 318, and / or TX processor 316, or antenna(s) 352, transmitter(s) 354, and / or TX processor 368), in response to receiving the report, transmits at least one beam carrying a position reference signal of the second node to the first node in the same direction as the direction of the one or more beams of interest, as at 718. In an aspect, each beam of the plurality of beams may be associated with a beam index, and the report may identify the one or more beams of interest using the beam index associated with each of the one or more beams of interest.

[0098] In one aspect, the second node 905 may transmit a synchronization signal for communicating with the second node on each of the plurality of beams. In that case, the at least one beam may include one or more interest beams updated to carry a positioning reference signal of the second node instead of a synchronization signal. Additionally or alternatively, the at least one beam may include at least one additional beam in addition to the one or more interest beams, wherein the at least one additional beam carries the positioning reference signal of the second node, and wherein the second node transmits the at least one additional beam in the direction of the one or more interest beams. Additionally or alternatively, the at least one beam includes at least one additional beam instead of one or more interest beams, wherein the at least one additional beam carries the positioning reference signal of the second node, and wherein the second node transmits the at least one additional beam in the direction of the one or more interest beams.

[0099] Those skilled in the art will appreciate that any of a variety of different techniques and methods may be used to represent information and signals. 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.

[0100] Further, it will be appreciated by those skilled in the art that the various exemplary logic blocks, modules, circuits, and algorithmic steps described in conjunction with the various aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. In order to clearly illustrate the interchangeability of such hardware and software, various exemplary components, blocks, modules, circuits, and steps have been generally described above from their functional perspective. Whether these functions are implemented in the form of hardware or software depends on the specific application and the design constraints imposed on the entire system. The technician may implement the described functions in different ways for each specific application, but such implementation decisions should not be interpreted as departing from the scope of the various aspects described herein.

[0101] Various illustrative logical blocks, modules, and circuits in conjunction with the aspects disclosed herein may be implemented or executed 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, 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. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or other such configurations).

[0102] The methods, sequences and / or algorithms in conjunction with the aspects disclosed herein may be directly embodied in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a random access memory (RAM), a flash memory, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a register, a hard disk, a removable disk, a CD-ROM, or any other form of non-transient computer-readable medium known in the art. An exemplary non-transient computer-readable medium may be coupled to a processor so that the processor can read information from the non-transient computer-readable medium and write information to the non-transient computer-readable medium. In an alternative case, the non-transient computer-readable medium may be integrated into the processor. The processor and the non-transient computer-readable medium may reside in an ASIC. The ASIC may reside in a user equipment (e.g., UE) or a base station. In an alternative case, the processor and the non-transient computer-readable medium may be discrete components in a user equipment or a base station.

[0103] In one or more exemplary aspects, the functions described herein can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the function can be stored as one or more instructions or codes on a non-transient computer-readable medium, or sent by a non-transient computer-readable medium. Computer-readable media may include storage media and / or communication media, and the storage media and / or communication media include any non-transient media that can facilitate the transfer of computer programs from one place to another. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or may be used to carry or store desired program codes in the form of instructions or data structures and any other medium that can be accessed by a computer. Moreover, any connection is appropriately referred to as a computer-readable medium. For example, if software is sent from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (such as infrared, radio and microwave), then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (such as infrared, radio and microwave) are included in the definition of medium. The terms disk and disc, which are used interchangeably herein, include compact disc (CD), laser disc, optical disc, digital video disc (DVD), floppy disk and Optical discs, which typically reproduce data magnetically and / or optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0104] Although the foregoing disclosure shows illustrative aspects, those skilled in the art will appreciate that various changes and modifications may be made herein without departing from the scope of the disclosure as defined by the appended claims. Furthermore, based on the various illustrative aspects described herein, those skilled in the art will appreciate that the functions, steps, and / or actions in any method described above and / or recited in any method claim attached hereto need not be performed in any particular order. Furthermore, with respect to any element described above or recited in the appended claims in singular form, those skilled in the art will appreciate that the singular form(s) also contemplates the plural unless a limitation to the singular form(s) is explicitly stated.

Claims

1. A method for reporting a beam of interest for position estimation, comprising: Receiving a plurality of beams from a user equipment UE at a base station; determining, by the base station, a time of arrival of each of the plurality of beams; identifying, by the base station, one or more beams of interest from the plurality of beams for determining a position estimate of the base station based on arrival times of the plurality of beams; sending, by the base station, to the UE, a report identifying each of the one or more beams of interest, wherein each of the plurality of beams carries a synchronization signal for the UE; and receiving, at the base station, after sending the report, at least one additional beam other than the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; or receiving, at the base station, after sending the report, at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; Each of the one or more beams of interest has an earlier arrival time at the base station than the remaining beams of the plurality of beams.

2. The method of claim 1, wherein: Receiving the multiple beams includes receiving a signal for each of the multiple beams at a base station and processing the signal to detect a received signal cluster of one or more detected channel taps corresponding to each of the multiple beams, and wherein the arrival time is determined based on the earliest detected channel tap for each of the multiple beams.

3. The method of claim 1, wherein: Each beam of the plurality of beams is associated with a beam index, and wherein the report identifies the one or more beams of interest using the beam index associated with each of the one or more beams of interest.

4. The method of claim 3, wherein: The one or more beams of interest include one of the plurality of beams having an earliest arrival time at the base station.

5. The method of claim 3, wherein: Each of the one or more beams of interest has an arrival time that is before a threshold delay from an earliest arrival time of a beam of the plurality of beams.

6. The method of claim 1, wherein: At least one beam of the plurality of beams other than the one or more beams of interest has a higher signal strength than a signal strength of the one or more beams of interest.

7. The method of claim 1, wherein: The multiple beams arrive at the base station from different angles.

8. The method of claim 1, wherein: The base station receives the plurality of beams in an extremely high frequency (EHF) band.

9. The method of claim 8, wherein: The EHF band includes a millimeter wave (mmW) frequency band.

10. The method of claim 1, further comprising: At the base station, the one or more interest beams are received after sending the report, wherein after sending the report, the one or more interest beams are updated to carry a positioning reference signal for the UE instead of a synchronization signal.

11. A method for transmitting a beam of interest for position estimation, comprising: A user equipment UE sends multiple beams to a base station; receiving, at the UE, from the base station a report identifying one or more beams of interest for determining a position estimate of the base station, wherein the one or more beams of interest are a subset of the plurality of beams, and wherein each of the one or more beams of interest has an earlier arrival time at the base station than remaining beams of the plurality of beams; and In response to receiving the report, sending, by the UE to the base station, at least one beam carrying a positioning reference signal of the UE in the same direction as the direction of the one or more beams of interest; wherein the at least one beam comprises at least one additional beam in addition to the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the UE transmits the at least one additional beam in the direction of the one or more beams of interest; or wherein the at least one beam includes at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal of the UE, and wherein the UE sends the at least one additional beam in the direction of the one or more beams of interest.

12. The method of claim 11, wherein: Each beam of the plurality of beams is associated with a beam index, and wherein the report identifies the one or more beams of interest using the beam index associated with each of the one or more beams of interest.

13. The method of claim 11, wherein: At least one beam of the plurality of beams other than the one or more beams of interest has a higher signal strength than a signal strength of the one or more beams of interest.

14. The method of claim 11, wherein: The UE transmits the multiple beams at different angles.

15. The method of claim 11, wherein: The UE transmits the plurality of beams in an extremely high frequency (EHF) band.

16. The method of claim 11, wherein: The UE transmits a synchronization signal for communicating with the UE on each of the plurality of beams.

17. The method of claim 16, wherein: The at least one beam includes one or more interest beams updated to carry a positioning reference signal for the UE instead of a synchronization signal.

18. An apparatus for reporting a beam of interest for position estimation, comprising: A transceiver of a base station is configured to receive a plurality of beams from a user equipment UE; as well as The at least one processor of the base station is configured to: determining a time of arrival of each of the plurality of beams; identifying, based on arrival times of the plurality of beams, one or more beams of interest from the plurality of beams for use in determining a position estimate of the base station; as well as causing the transceiver to send a report identifying each of the one or more beams of interest to the UE, wherein each of the plurality of beams carries a synchronization signal for the UE; and receiving, at the base station, after sending the report, at least one additional beam other than the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; or receiving, at the base station, after sending the report, at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; Each of the one or more beams of interest has an earlier arrival time at the base station than the remaining beams of the plurality of beams.

19. An apparatus for transmitting a beam of interest for position estimation, comprising: A transmitter of a user equipment UE, configured to transmit a plurality of beams to a base station; as well as a receiver of the UE configured to receive, from the base station, a report identifying one or more beams of interest for determining a position estimate of the base station, wherein the one or more beams of interest are a subset of the plurality of beams, and wherein each of the one or more beams of interest has an earlier arrival time at the base station than remaining beams of the plurality of beams; The transmitter is further configured to, in response to receiving the report, transmit at least one beam carrying a positioning reference signal of the UE to the base station in the same direction as the direction of the one or more beams of interest. wherein the at least one beam comprises at least one additional beam in addition to the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the UE transmits the at least one additional beam in the direction of the one or more beams of interest; or wherein the at least one beam includes at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal of the UE, and wherein the UE sends the at least one additional beam in the direction of the one or more beams of interest.

20. A non-transitory computer-readable medium storing computer-executable instructions for reporting a beam of interest for position estimation, which when executed by at least one processor of a base station causes the base station to: receiving a plurality of beams from a user equipment UE; determining a time of arrival of each of the plurality of beams; identifying, based on arrival times of the plurality of beams, one or more beams of interest from the plurality of beams for use in determining a position estimate of the base station; sending a report identifying each of the one or more beams of interest to the UE, wherein each of the plurality of beams carries a synchronization signal for the UE; and receiving, after sending the report, at least one additional beam other than the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; or receiving, after sending the report, at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the base station receives the at least one additional beam from a direction of the one or more beams of interest; Each of the one or more beams of interest has an earlier arrival time at the base station than the remaining beams of the plurality of beams.

21. A non-transitory computer-readable medium storing computer-executable instructions for transmitting a beam of interest for position estimation, which, when executed by at least one processor of a user equipment (UE), causes the UE to: sending multiple beams to a base station; receiving a report from the base station identifying one or more beams of interest for determining a position estimate of the base station, wherein: The one or more beams of interest are a subset of the plurality of beams, and wherein each of the one or more beams of interest has an earlier arrival time at the base station than remaining beams of the plurality of beams; and In response to receiving the report, sending at least one beam carrying a positioning reference signal for the UE to the base station in the same direction as the direction of the one or more beams of interest; wherein the at least one beam comprises at least one additional beam in addition to the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal for the UE, and wherein the UE transmits the at least one additional beam in the direction of the one or more beams of interest; or wherein the at least one beam includes at least one additional beam instead of the one or more beams of interest, wherein the at least one additional beam carries a positioning reference signal of the UE, and wherein the UE sends the at least one additional beam in the direction of the one or more beams of interest.

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