Determine the transmission timing of the positioning beacon from the reception time of the reference signal

Abstract

In an embodiment, a first node receives a plurality of beams from a second node. The first node determines an arrival time of each of the plurality of beams. The first node identifies one or more first beams of interest for a positioning process from the plurality of beams based on the arrival times of the plurality of beams. The first node determines a first reference timing based on the arrival time of a given beam among the identified one or more first beams of interest. The first node sends a positioning beacon to the second node according to the first reference timing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 676,900, filed on May 25, 2018, entitled “DETERMING TRANSMISSIONTIMING OF A POSITIONING BEACON FROM A TIME OF RECEPTION OF A REFERENCESIGNAL,” which is pending and assigned to the present assignee and is hereby expressly incorporated by reference in its entirety. Technical Field

[0003] Various aspects described herein relate generally to wireless communication systems, and more particularly, to determining the transmission timing of a location beacon from the reception time of a reference signal. Background Art

[0004] Wireless communication systems have evolved over many 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). Currently, many different types of wireless communication systems are used, 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.

[0005] The fifth generation (5G) mobile standard requires higher data transfer speeds, a greater number of connections and better coverage, among other improvements. The 5G standard according to the Next Generation Mobile Networks Alliance is designed to provide data rates of tens of megabits per second to each of tens of thousands of users, and 1 gigabit per second to dozens of workers on an office floor. In order to support large sensor deployments, 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.

[0006] Some wireless communication networks (such as 5G) support operation at very high and even extremely high frequency (EHF) bands, such as millimeter wave (mmW) bands (typically 1mm to 10mm wavelength, or 30 to 300GHz). These extremely high frequencies can support very high throughputs, such as up to six gigabits per second (Gbps). However, one of the challenges of wireless communication at very high or extremely high frequencies is that significant propagation losses may occur due to the high frequencies. As the frequency increases, the wavelength can decrease, and the propagation loss can also increase. At the mmW band, the propagation loss can be severe. For example, relative to the propagation loss observed in the 2.4GHz or 5GHz bands, the propagation loss can be about 22 to 27dB.

[0007] In multiple-input multiple-output (MIMO) and large-scale MIMO systems in any frequency band, propagation loss is also a problem. As used herein, the term MIMO will generally refer to both MIMO and large-scale MIMO. MIMO is a method of doubling the capacity of a radio link by using multiple transmit and receive antennas to utilize multipath propagation. The reason for multipath propagation is that radio frequency (RF) signals not only travel through the shortest path between the transmitter and the receiver (the path may be a line of sight (LOS) path), but also travel on several other paths because they are scattered from the transmitter and reflected from other objects (such as hills, buildings, water, etc.) on their way to the receiver. The transmitter in the MIMO system includes multiple antennas, and multipath propagation is utilized by guiding these antennas to each send the same RF signal on the same radio channel to the receiver. The receiver is also equipped with multiple antennas, which 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 combine them into a single RF signal. Propagation losses are also a problem in MIMO systems because the transmitter sends each RF signal at a lower power level than a single RF signal.

[0008] To address the propagation loss problem in mmW band systems and MIMO systems, the transmitter can use beamforming to extend the RF signal coverage. In particular, transmit beamforming is a technique for transmitting RF signals in a specific direction, while receive beamforming is a technique for increasing 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 or separately from each other, and 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 the fixed antenna pattern or radiation pattern of the antenna. With beamforming, the transmitter determines the position of a given receiver 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 directivity 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 that create RF beams that can be "steered" to point in different directions (also called a "phased array" or "antenna array") without actually moving the antennas. Specifically, RF currents are fed to the various antennas in 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.

[0009] To support position estimation in terrestrial wireless networks, a mobile device may be configured to measure and report an 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).

[0010] In the case where a transmitter uses beamforming to transmit an RF signal, the beam of interest for data communication between the transmitter and the receiver will be the beam carrying the RF signal with the highest received signal strength (or the highest received signal to noise plus interference ratio (SINR), e.g., in the presence of a directional interfering signal). 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 affected. For example, in a scenario where the beam with the highest received signal strength travels on a non-LOS (NLOS) path that is longer than the shortest path (i.e., the LOS path or the shortest NLOS path), the RF signal may arrive later than the RF signal(s) received on the shortest path due to propagation delays. Thus, if the receiver is performing a task that requires precise timing measurements and the beam with the highest received signal strength is affected by the longer propagation delay, the beam with the highest received signal strength may not be optimal for the task at hand. Summary of the invention

[0011] An embodiment of the present disclosure relates to a method for operating a first node, comprising: receiving multiple beams from a second node at the first node, determining, by the first node, an arrival time of each of the multiple beams, identifying, by the first node, one or more first beams of interest for a positioning process from the multiple beams based on the arrival times of the multiple beams, determining a first reference timing based on the arrival time of a given beam among the identified one or more first beams of interest, and sending, by the first node, a positioning beacon to the second node according to the first reference timing.

[0012] Another embodiment of the present disclosure relates to a first node, comprising: a component for receiving multiple beams from a second node, a component for determining the arrival time of each of the multiple beams, a component for identifying one or more first beams of interest for a positioning process from the multiple beams based on the arrival times of the multiple beams, a component for determining a first reference timing based on the arrival time of a given beam among the identified one or more first beams of interest, and a component for sending a positioning beacon to the second node according to the first reference timing.

[0013] Another embodiment of the present disclosure relates to a first node, comprising a memory and at least one processor coupled to the memory and a communication interface, the at least one processor being configured to: receive multiple beams from a second node, determine an arrival time of each of the multiple beams, identify one or more first beams of interest for a positioning process from the multiple beams based on the arrival times of the multiple beams, determine a first reference timing based on the arrival time of a given beam among the identified one or more first beams of interest, and send a positioning beacon to the second node according to the first reference timing.

[0014] Another embodiment of the present disclosure relates to a non-transitory computer-readable medium, comprising instructions stored thereon, which, when executed by a first node, cause the first node to perform operations, the instructions including: at least one instruction configured to cause the first node to receive multiple beams from a second node, at least one instruction configured to cause the first node to determine an arrival time of each of the multiple beams, at least one instruction configured to cause the first node to identify one or more first beams of interest for a positioning process from the multiple beams based on the arrival times of the multiple beams, at least one instruction configured to cause the first node to determine a first reference timing based on the arrival time of a given beam among the identified one or more first beams of interest, and at least one instruction configured to cause the first node to send a positioning beacon to the second node according to the first reference timing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A more complete understanding of the various aspects described herein, together with many of the attendant advantages thereof, will be readily obtained as the same become 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, and in which:

[0016] Figure 1

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

[0017] Figure 2A and 2B Example wireless network structures in accordance with various aspects are illustrated.

[0018] Figure 3

[0013] Illustrated are exemplary base stations and exemplary UEs in an access network according to various aspects.

[0019] Figure 4 An exemplary wireless communication system in accordance with various aspects of the present disclosure is illustrated.

[0020] Figure 5 An exemplary wireless communication system in accordance with various aspects of the present disclosure is illustrated.

[0021] Fig. 6A is a graph illustrating RF channel response at a UE over time according to aspects of the present disclosure.

[0022] Figure 6B An exemplary separation of clusters in angle of departure (AoD) is illustrated in accordance with aspects of the present disclosure.

[0023] Figures 7 to 11 Exemplary methods according to various aspects are illustrated. DETAILED DESCRIPTION

[0024] Various aspects described herein generally relate to wireless communication systems, and more specifically, to determining the transmission timing of a positioning beacon from the reception time of a reference signal. In one aspect, a first node (e.g., a user device, a base station, or (one or more) antennas associated with a base station) receives multiple beams from a second node. The first node determines the arrival time of each beam in the multiple beams. The first node identifies one or more beams of interest for a positioning process from the multiple beams based on the arrival time of the multiple beams. The first node determines the reference timing based on the arrival time of a given beam among the identified one or more first beams of interest. The first node sends a positioning beacon to the second node by the first node according to the reference timing. Specifically, in one embodiment, the reference timing is the transmission time of the positioning beacon, wherein the reference timing is offset by a given amount of time relative to the arrival time of the given beam. Then, the second node uses the arrival time of the positioning beacon at the second node to estimate the round trip propagation time (RTT). The RTT is then used to estimate the distance between the nodes and ultimately estimate the position of the first node.

[0025] These and other aspects are disclosed in the following description and related drawings to illustrate specific examples related to the exemplary aspects. Alternative aspects will be apparent to those skilled in the relevant art after reading this disclosure and may be constructed and practiced without departing from the scope or spirit of the disclosure. In addition, well-known elements will not be described in detail or may be omitted to avoid obscuring the relevant details of the aspects disclosed herein.

[0026] 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.

[0027] 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 also intended to include the plural forms, unless the context clearly indicates otherwise. It will be further understood by those skilled in the art that, as used herein, the terms "comprise", "comprising", "include", and / or "including" specify the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0028] In addition, various aspects can be described according to, for example, a sequence of actions to be performed by elements of a computing device. It will be appreciated by those skilled in the art that the various actions described herein can be performed by a specific circuit (e.g., an application specific integrated circuit (ASIC)), by program instructions executed by one or more processors, or by a combination of the two. In addition, it can be considered that these action sequences described herein are fully implemented in any form of non-transitory computer-readable medium on which a corresponding computer instruction set is stored, which, when executed, will cause the associated processor to perform the functions described herein. Therefore, the various aspects described herein can be implemented in several different forms, all of which are considered to be within the scope of the subject matter claimed for protection. In addition, for each aspect described herein, the corresponding form of any such aspect can be described herein as, for example, "logic configured as..." and / or other structural components configured to perform the described actions.

[0029] 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", "phone", "access terminal", "subscriber device", "subscriber terminal", "subscriber station", "terminal" and variants thereof may interchangeably 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 the other device. In addition, these terms are intended to include all devices that can communicate with the core network via a radio access network (RAN), including wireless and wired communication devices, and through the core network, the UE can be connected to external networks such as the Internet and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through a wired access network, a wireless local area network (WLAN) (e.g., based on IEEE 802.11, etc.). The UE may be implemented by any of several 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 smart phone, a tablet, a tracking device, an asset tag, and the like. The communication link by which the UE may signal to the RAN is referred to as an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, and the like). The communication link by which the RAN may signal 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, and the like). As used herein, the term traffic channel (TCH) may refer to an uplink / reverse or downlink / forward traffic channel.

[0030] According to various aspects, Figure 1 An exemplary wireless communication system 100 is illustrated. 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) (in which the wireless communication system 100 corresponds to an LTE network), gNodeBs (gNBs) (in which the wireless communication system 100 corresponds to a 5G network), or a combination of both, and the small cells may include femto cells, pico cells, micro cells, etc.

[0031] The base stations 102 may collectively form a radio access network (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: transmitting user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution for 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) over a backhaul link 134, which may be wired or wireless.

[0032] Base stations 102 may communicate wirelessly with UEs 104. Each of base stations 102 may provide communication coverage for a corresponding geographic coverage area 110. In one aspect, although not specifically described herein, base stations 102 may provide communication coverage for a corresponding geographic coverage area 110. Figure 1 1 , but the 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 the base station 102. As used herein, the term "cell" or "sector" may correspond to one of the multiple cells of the base station 102, or to the base station 102 itself, depending on the context.

[0033] 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 the geographic coverage area 110 of one or more macrocell base stations 102. A network that includes both small cells and macrocells may be referred to as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB), which may provide services to a restricted group referred to 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 referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also referred to 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 with respect to DL and UL (eg, more or fewer carriers may be allocated for DL ​​compared to UL).

[0034] 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 in an unlicensed spectrum (e.g., 5 GHz) via a communication link 154. 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 the channel is available.

[0035] 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 5GHz 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 and / or increase the capacity of the access network. LTE in the unlicensed spectrum can be referred to as LTE unlicensed (LTE-U), license assisted access (LAA) or MulteFire.

[0036] The wireless communication system 100 may also include a mmW base station 180, which can communicate with UE 182 at mmW frequencies and / or near mmW frequencies. Extremely high frequency (EHF) is part of RF in the electromagnetic spectrum. The range of EHF is 30GHz to 300GHz, and the wavelength is between 1 mm and 10 mm. The radio waves in this band can be called millimeter waves. Close to mmW, it can be extended to 3GHz frequencies with a wavelength of 100 mm. The super high frequency (SHF) band extends between 3GHz and 30GHz, which is also called centimeter waves. Communication using mmW / near mmW radio frequency bands has high path loss and a relatively short range. The mmW base station 180 can utilize beamforming 184 with UE 182 to compensate for the extremely high path loss and short range. In addition, it will be appreciated that in alternative configurations, one or more base stations 102 can also use mmW or near mmW and beamforming to send. Thus, it will be appreciated that the foregoing illustrations are merely examples and should not be interpreted as limiting the various aspects disclosed herein.

[0037] The wireless communication system 100 may also include one or more UEs (such as UE 190) that are indirectly connected to one or more communication networks via one or more device-to-device (D2D) or peer-to-peer (P2P) links. Figure 1In an embodiment of the present invention, 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 cellular connectivity) and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which UE 190 can indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links 192-194 can be supported by any well-known D2D radio access technology (RAT) such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth, etc.

[0038] According to various aspects, Figure 2A An example wireless network architecture 200 is illustrated. For example, the Next Generation Core (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, IP routing, etc.) that operate in concert to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect the gNB 222 to the NGC 210, and in particular to the control plane function 214 and the user plane function 212. In additional configurations, 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. Accordingly, in some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of the eNBs 224 and the gNBs 222. The gNB 222 or the eNB 224 may communicate with the UE 240 (e.g., Figure 1 2, such as UE 104, 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.

[0039] According to various aspects, Figure 2BAnother example wireless network structure 250 is illustrated. For example, an evolved packet core (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 conjunction to form a core network. An S1 user plane interface (S1-U) 263 and an 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 additional configurations, 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 a backhaul connection 223 with or without a gNB direct connection to the EPC 260. Accordingly, 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. The gNB 222 or the eNB 224 may communicate with a UE 240 (e.g., Figure 1 240, such as UE 104, 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).

[0040] According to various aspects, Figure 3An exemplary base station 310 (e.g., eNB, gNB, small cell AP, WLAN AP, etc.) is illustrated in communication with an exemplary UE 350 in a wireless network. In the DL, IP packets from the core network (NGC 210 / EPC 260) may be provided to a controller / processor 375. The controller / processor 375 implements functions for a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity checking), and switching support functions; RLC layer functions associated with transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data; and MAC layer functions associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0041] 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 OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate 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. The channel estimates may be derived from a reference signal 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.

[0042] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to 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 stream going to the UE 350. If multiple spatial streams go to the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. Then, the RX processor 356 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 the channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by base station 310. The data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0043] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the core network. The controller / processor 359 is also responsible for error detection.

[0044] Similar to the functions described in conjunction with the DL transmission of the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity checking); RLC layer functions associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel priority.

[0045] The TX processor 368 may select an appropriate coding and modulation scheme and facilitate spatial processing using channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0046] 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.

[0047] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the core network. The controller / processor 375 is also responsible for error detection.

[0048] Figure 4An exemplary wireless communication system 400 is illustrated in accordance with various aspects of the present disclosure. Figure 4 In the example above, Figure 1 A UE 404 corresponding to any of the described UEs (e.g., UE 104, UE 182, UE 190, etc.) is attempting to compute an estimate of its location, or assisting another entity (e.g., a base station or core network component, another UE, a location server, a third-party application, etc.) in computing an estimate of its location. UE 404 may wirelessly communicate with a plurality of base stations 402a-d (collectively, base stations 402) using RF signals and standardized protocols for modulation of RF signals and exchange of information packets, which may be associated with Figure 1 102 or 180 and / or WLAN AP 150 in the wireless communication system 400. By extracting different types of information from the exchanged RF signals and utilizing the layout of the wireless communication system 400 (i.e., base station locations, geometry, etc.), the UE 404 can determine its position in a predetermined reference coordinate system, or assist in determining its position. In one aspect, the UE 404 can use a two-dimensional coordinate system to specify its position; however, the aspects disclosed herein are not limited thereto, and if additional dimensions are desired, the aspects disclosed herein can also be applied to determine the position using a three-dimensional coordinate system. In addition, although Figure 4 One UE 404 and four base stations 402 are illustrated, but it will be appreciated that there may be more UEs 404 and more or fewer base stations 402 .

[0049] 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), synchronization signals, etc.) to the UE 404 in its coverage area to enable the UE 404 to measure reference RF signal timing differences (e.g., OTDOA or RSTD) between pairs of network nodes and / or identify the beam that best excites the LOS or shortest radio path between the UE 404 and the transmitting base station 402. Identifying the LOS / shortest path beam(s) is of interest not only because these beams can then be used for OTDOA measurements between a pair of base stations 402, but also because identifying these beams can directly provide some positioning information based on the beam direction. Moreover, these beams can then be used for other position estimation methods that require accurate ToA, such as methods based on round-trip time estimation.

[0050] 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, wherein 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 signal. In addition, as used herein, a "node" may refer to a network node or a UE.

[0051] 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 for 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 itself without using assistance data. UE 404 (e.g., based in part on assistance data, if provided) may measure and (optionally) report OTDOA from various network nodes and / or RSTD between reference RF signals received from pairs of network nodes. Using these measurements and the known location of the measured network node (i.e., the (one or more) base stations 402 or (one or more) 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 node, and thereby calculate the location of UE 404.

[0052] The term "position estimate" is used herein to refer to an estimate of the location of UE 404, which may be geographic (e.g., may include latitude, longitude, and possibly altitude) or urban (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 "location", "position", "fix", "position fix", "location fix", "location estimate", "position estimate", or by other terms. The means of obtaining a position estimate may be collectively referred to as "positioning", "locating", or "position fixing". A specific solution for obtaining a position estimate may be referred to as a "position solution". A specific method for obtaining a position estimate as part of a position solution may be referred to as a "position method" or "positioning method".

[0053] The term "base station" may refer to a single physical transmission point or to multiple physical transmission points that may or may not be co-located. For example, where the term "base station" refers to a single physical transmission point, the physical transmission point may be a base station antenna corresponding to a cell of a base station (e.g., base station 402). Where the term "base station" refers to multiple co-located physical transmission points, the physical transmission point may be an array of base station antennas (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 point may be a serving base station that receives measurement reports from a UE (e.g., UE 404) and neighboring base stations whose reference RF signals the UE is measuring. Thus, Figure 4 The illustrated aspect of base stations 402a and 402b forming a DAS / RRH 420. For example, base station 402a can be a serving base station for UE 404, and base station 402b can be a neighboring base station for UE 404. As such, base station 402b can be an RRH for base station 402a. Base stations 402a and 402b can communicate with each other via a wired or wireless link 422.

[0054] In order to accurately determine the location of UE 404 using OTDOA and / or RSTD between RF signals received from paired network nodes, UE 404 needs to measure a reference RF signal received through a LOS path (or the shortest NLOS path, if a LOS path is not available) between UE 404 and a network node (e.g., base station 402, antenna). However, RF signals travel not only through the LOS / shortest path between a transmitter and a receiver, but also through several other paths, as RF signals scatter from the transmitter and reflect from other objects (such as hills, buildings, water, etc.) on their way to the receiver. Therefore, Figure 4 Several LOS paths 410 and several NLOS paths 412 between base station 402 and UE 404 are shown. 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 from an object 430 (e.g., a building). It should be appreciated that 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). In addition, as used herein, the term "LOS path" refers to the shortest path between a transmitter and a receiver, and may not be an actual LOS path, but rather the shortest NLOS path.

[0055] In one aspect, one or more of the 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 therefore 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 an electromagnetic wave that transmits information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit 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.

[0056] 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 (as indicated by, for example, received signal received power (RSRP) or, in the presence of a directional interfering signal, by SINR), 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, they will be the same beam. However, in other frequency bands (such as mmW, where a large number of antenna elements can typically be used to create a narrow transmit beam), they may not be the same beam. As described below with reference to Figure 5 As described, in some cases, the signal strength of the RF signal on LOS path 410 may be weaker (eg, due to obstacles) than the signal strength of the RF signal on NLOS path 412 where the RF signal arrives later due to propagation delay.

[0057] Figure 5 An exemplary wireless communication system 500 is illustrated in accordance with various aspects of the present disclosure. Figure 5 In the example, you can Figure 4 UE 504 corresponding to UE 404 in the example attempts to calculate an estimate of its location, or assists another entity (e.g., a base station or core network component, another UE, a location server, a third-party application, etc.) to calculate an estimate of its location. UE 504 can communicate wirelessly with base station 502 using RF signals and standardized protocols for modulation of RF signals and exchange of information packets, and base station 502 can communicate with Figure 4 Corresponding to one of the base stations 402 in.

[0058] 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 array of antennas of base station 502. Figure 5 Base station 502 is illustrated as transmitting five beams, but it can be appreciated that there may be more or fewer than five beams, that beam shapes such as peak gain, width, and sidelobe gain may differ between the transmitted beams, and that some of the beams may be transmitted by different base stations.

[0059] In order to distinguish an RF signal associated with one beam from an RF signal associated with another beam, a beam index can be assigned to each of the multiple beams 511-515. Moreover, the RF signal associated with a specific beam in the multiple beams 511-515 can carry a beam index indicator. The beam index can also be derived from the transmission time of the RF signal (e.g., frame, time slot and / or OFDM symbol number). The beam index indicator can be, for example, a three-bit field for uniquely distinguishing up to eight beams. If two different RF signals with different beam indices are received, this will indicate that the RF signals are transmitted using different beams. If two different RF signals share a common beam index, this will indicate that the different RF signals are transmitted using the same beam. Another way to describe sending two RF signals using the same beam refers to the (one or more) antenna ports used to send the first RF signal being quasi-collocated in space with the (one or more) antenna ports used to send the second RF signal.

[0060] 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 5NLOS data stream 523 and LOS data stream 524 are shown as single lines (dashed and solid, respectively), but as will be appreciated, NLOS data stream 523 and LOS data stream 524 may each include multiple rays (i.e., "clusters") as they arrive at UE 504, e.g., due to the propagation characteristics of RF signals through multipath channels. For example, clusters of RF signals are formed when electromagnetic waves reflect from 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.

[0061] exist Figure 5 In the example of FIG. 5 , NLOS data stream 523 is not initially directed to UE 504, but, as will be appreciated, it may also be directed to UE 504. Figure 4 4. However, it is reflected by reflector 540 (e.g., a building) and reaches UE 504 without obstacles, and therefore, it can still be a relatively strong RF signal. In contrast, LOS data stream 524 is directed toward UE 504, but passes through obstacle 530 (e.g., vegetation, buildings, hills, disruptive environments such as clouds or smoke, etc.), which significantly degrades the RF signal. As should be appreciated, although LOS data stream 524 is weaker than NLOS data stream 523, LOS data stream 524 will reach UE 504 before NLOS data stream 523 because it follows a shorter path from base station 502 to UE 504.

[0062] As described above, the beam of interest for data communication between a base station (e.g., base station 502) and a UE (e.g., UE 504) is a beam that carries an RF signal that reaches the UE with the highest signal strength (e.g., the highest RSRP or SINR), while the target beam for position estimation is a beam that carries an 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) weakly excites the LOS path (even if not focused along the LOS path due to the propagation characteristics of the RF signal), that 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 when performing positioning measurements.

[0063] While the beam of interest for data communication and the beam of interest for position estimation may be the same beam for some frequency bands, they may not be the same beam for other frequency bands (such as mmW). Figure 5, in the case where UE 504 is conducting a data communication session with base station 502 (e.g., where 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 unblocked NLOS data stream 523. However, the beam of interest for position estimation would be beam 514 because, although it is blocked, it carries the strongest LOS data stream 524.

[0064] Fig. 6A 6 is a graph 600A illustrating RF channel response at a receiver (eg, UE 504) over time according to aspects of the present disclosure. Fig. 6A Under the channel shown in , the receiver receives a first cluster of two RF signals on a channel tap at time T1, a second cluster of five RF signals on the channel tap at time T2, a third cluster of five RF signals on the channel tap at time T3, and a fourth cluster of four RF signals on the channel tap at time T4. Fig. 6A In the example of , because the first cluster of RF signals at time T1 arrives first, it is assumed to be a LOS data stream (i.e., a data stream that arrives via LOS or the shortest path) and may correspond to LOS data stream 524. The third cluster at time T3 consists of the strongest RF signal and may correspond to NLOS data stream 523. From the transmitter side, each cluster of received RF signals may include a portion of the RF signal transmitted at a different angle, and therefore each cluster may be said to have a different angle of deviation (AoD) from the transmitter. Figure 6B FIG. 600B is a diagram illustrating this separation of clusters in AoD. RF signals transmitted in AoD range 602a may be Fig. 6A The RF signal transmitted in the AoD range 602b may correspond to one of the clusters (e.g., “cluster 1”) in the AoD range 602b. Fig. 6A , corresponding to different clusters (e.g., “Cluster 3”) in . Note that, although Figure 6B The AoD ranges of the two clusters depicted in are spatially isolated, but even if the clusters are separated in time, the AoD ranges of some clusters will partially overlap. This can occur, for example, when two separate buildings at the same AoD as the transmitter reflect the signal toward the receiver. Note that although Fig. 6A Clusters of two to five channel taps are illustrated, but it should be appreciated that a cluster may have more or fewer channel taps than the illustrated number of channel taps.

[0065] As in Figure 5In the example of , a base station may transmit multiple RF signal beams using beamforming such that one of the beams (e.g., beam 514) is directed toward the AoD range 602a of a first cluster of RF signals, and a different beam (e.g., beam 513) is directed toward the AoD range 602b of a third cluster of RF signals. The signal strength of a cluster in the post-beamforming channel response (i.e., the channel response when the transmitted RF signal is beamformed rather than omnidirectional) will be scaled by the beam gain along the AoD of that cluster. In that case, the beams of interest for positioning would be the beams directed toward the AoD of the first cluster of RF signals because they arrive first, while the beams of interest for data communications would be the beams directed toward the AoD of the third cluster of RF signals because they are the strongest.

[0066] Generally speaking, when transmitting an RF signal, the transmitter does not know along what path it will reach the receiver (e.g., UE 504) or when it will reach the receiver, and therefore transmits the RF signal with equal amounts of energy on different antenna ports. Alternatively, the transmitter may beamform the RF signal in different directions through multiple transmission opportunities and obtain measurement feedback from the receiver to determine the radio path explicitly or implicitly.

[0067] Note that while the techniques disclosed herein have been 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 certain embodiments, receive beamforming may also be used in conjunction with the transmit beamforming described above.

[0068] As disclosed above, in some frequency bands, the shortest path (which, as described above, may be either 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). Thus, where a transmitter uses beamforming to transmit RF signals, 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). As such, it would be beneficial for a receiver to identify and report the beam of interest for position estimation to the transmitter so that the transmitter can then modify the set of beams transmitted to assist the receiver in performing position estimation.

[0069] Figure 7An exemplary method according to an aspect of the present disclosure is illustrated. At 702, a second node 703 (referred to as a "transmitter") sends 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 be a UE (such as UE 350 / 404 / 504), and the second node 703 may be a base station (such as base station 310 / 402 / 502). However, in one aspect, the first node 701 may be a base station, and the second node 703 may be a UE, or both the first node 701 and the second node 703 may be UEs or base stations. As yet another alternative, the second node 703 may be a single antenna or antenna array capable of beamforming by a base station or UE.

[0070] exist Figure 7 In the example of , the second node 703 transmits a set of three beams 705, 707, and 709. These beams may be transmitted simultaneously, but are distinguishable 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 in Figure 5 and Figure 6B As shown in Figure 7 In the example of , beam 707 (shown as a straight line) can be along the shortest path (e.g., a LOS path or the shortest NLOS path when the LOS path cannot be detected due to obstacles) from the second node 703 to the first node 701, while beams 701 and 701 can be along a longer (e.g., NLOS) path from the second node 703 to the first node 701. As will be appreciated, there can be more or less than three beams, as described above in Figure 4 and Figure 5 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, and the like.

[0071] 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 signal of the received beam with (the conjugate of) the known transmitted RF signal and determine the channel tap from the peak of the correlation. The first node 701 may also estimate the noise and eliminate less reliable channel taps that are comparable to the noise floor. The first node 701 may also employ techniques to eliminate false side peaks around strong channel taps, where it is well known that the false side peaks are caused by the band-limited reception at 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.

[0072] 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 commonly deployed antenna systems do 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) along 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 be along the shortest detectable path to the first node 701. As such, rather than 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 among beams 705, 707, and 709 as one or more beams of interest. For example, the one or more beams of interest may be beams 705, 707, or 709 having the first detected channel tap. Or the one or more beams of interest may be N (greater than 1, e.g., 2) beams having the earliest detected channel taps. Or the one or more beams of interest may be one or N beams whose first detected channel taps are within a predetermined delay (e.g., 10 nanoseconds) of the first detected tap of the beam having the earliest detected first tap. With the speed of light being approximately 0.3 meters per nanosecond (ns), a 10 ns error or ambiguity in the arrival time corresponds to a position / range error of approximately 3 meters. Thus, the delay may be determined by the desired accuracy or achievable accuracy 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. In one aspect, 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 is usually done by convention), the number N of beams to report, and / or a "delay" parameter for selecting the N beams.

[0073] 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.

[0074] At 714, the second node 703 receives the report. Figure 1), the first node 701 may send a report at 712, and the second node 703 may receive the report at 714. The reception point at which the second node 703 receives the report may or may not be co-located with the transmission point(s) at which the second node 703 transmits beams 705, 707, 709. For example, the reception point at which the second node receives the report may be assigned a cell identifier different from the transmission point at which the node transmits the beam. The reception point may be a serving cell, and the transmission point may be a non-serving cell (such as a neighboring cell).

[0075] At 716, the second node 703 may select a second set of beams to transmit based on the received report. For example, where the first node 701 attempts 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). As such, on the one hand, after the beams have been modified to transmit reference RF signals, the second node 703 may also transmit one or more finer (more focused) beams around the beam(s) identified in the report. 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).

[0076] As another example, again 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, where the second node is a base station), and the selection of beams at 716 may be for the transmission of specific positioning beacons solely for the benefit of the first node, and may be transmitted with different periodicities or aperiodically.

[0077] In one aspect, in the case 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 (UE) to send an additional reference beam 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. Therefore, the operation at 708 is a way to shortlist (one or more) beams of interest and then use the last selected (one or more) beams for ongoing position estimation while discarding "uninteresting" beams.

[0078] 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 identifies 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 correspond to additional beams that transmit reference RF signals in the direction of the beam identified in the report received at 714. On the other hand, beams 711 and 713 may be two new beams that transmit reference RF signals in the direction of the beam identified in the report received at 714. In one aspect, although not shown, prior to transmitting beams 711 and 713 , second node 703 may transmit an indication of which beams it has selected to transmit at 718 .

[0079] exist Figure 7 In the example of FIG. 7 , two beams (711 and 713) are transmitted at 718. However, as will be appreciated, this is merely an example, and there may be more or fewer beams transmitted at 718. Figure 7 , beam 711 is shown as being along a LOS path, and beam 713 is shown as being along a NLOS path (ie, reflected from an object). However, as will be appreciated, both beams 711 and 713 may be along a LOS path, or both may be reflected.

[0080] At 720, the first node 701 receives the beams 711 and 713. The first node 701 may perform together with a plurality of second nodes including the second node 703 Figure 7The process of performing OTDOA measurements in order to receive a sufficient number of shortest path beams that can be accurately measured to calculate a location estimate or to assist in the calculation of a location 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 location estimate of the first node 701.

[0081] Figure 8 An exemplary method 800 for determining a reference timing for transmitting a positioning beacon according to an embodiment of the present disclosure is illustrated. The method 800 may be performed by a first node 805 (such as Figure 7 In the example, the base station 310 or the UE 350 or the first node 701 is performed. Moreover, as part of the UE positioning process, a UE (eg, the UE 350) and multiple base stations may be performed. Figure 8 process.

[0082] Reference Figure 8 At 802, a 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 a signal from a second node (e.g., Figure 7 The base station 310 or UE 350 or second node 703 in the embodiment receives a plurality of beams (e.g., beams 511-515). At 804, the first node 805 (e.g., RX processor 370 and / or controller / processor 375, or RX processor 356 and / or controller / processor 359) determines an arrival time of each beam in the plurality of beams. 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 positioning process based on the arrival times of the plurality of beams.

[0083] In another example, in addition to the arrival times of the plurality of beams, the first node 805 may also consider one or more auxiliary criteria at 804 and / or 806. For example, the one or more auxiliary criteria may be considered at 804 such that the first node 805 does not calculate the arrival time(s) of the one or more beams that do not satisfy the one or more auxiliary criteria. Alternatively, the one or more auxiliary criteria may be considered at 806 such that any arrival time(s) of the beams that do not satisfy the one or more auxiliary criteria are excluded by the first node 805 from selection as the identified beam(s) of interest. In either case, in one or more embodiments, the beams that do not satisfy the one or more auxiliary criteria do not become part of the identified one or more beams at 806.

[0084] In one example of one or more auxiliary criteria, the identified one or more beams of interest may be required to meet at least one quality threshold (e.g., RSRP is above a minimum threshold, or at least one channel tap has a minimum received signal strength or a minimum signal-to-noise ratio). In one example, at least one quality threshold may be configured by a network component such as a base station (e.g., depending on the implementation, the network component may correspond to the first node 805 or the second node). In this way, the network component may improve the reliability of beam-specific ToA detection and may prevent a poorly implemented first node detector (e.g., if the first node 805 is a UE, then a UE detector) from confusing random noise spikes as the earliest channel taps for a particular beam. In another example, if the channel taps of any detected reference beam do not meet the quality threshold, the first node 805 may ignore the quality threshold and freely select the beam with the earliest ToA, regardless of the quality of the detected signal for that beam (e.g., received signal strength, signal-to-noise ratio, etc.).

[0085] Reference Figure 8 At 808, the first node 805 (e.g., RX processor 370 and / or controller / processor 375, or RX processor 356 and / or controller / processor 359) determines a reference timing based on the arrival time of a given beam among the identified one or more beams of interest. At 810, the first node 805 (e.g., TX processor 316 and / or controller / processor 375, or TX processor 368 and / or controller / processor 359) sends a positioning beacon to the second node according to the reference timing. Although Figure 8 It is not explicitly shown in the figure, but it can be used at the second node Figure 8 The positioning beacon sent at 810 in is used to calculate a timing metric (e.g., round-trip time or RTT).

[0086] Reference Figure 8In an embodiment, the reference timing is the transmission time of the location beacon. The second node then uses the arrival time (ToA) or reception time of this location beacon at the second node to estimate the round trip time (RTT). The RTT is then used to estimate the distance between the nodes and ultimately to estimate the position of the first node.

[0087] More specifically, in one example, the reference timing may be based on information received at the first node from the second node (e.g., in performing Figure 8 ), the information indicating the timing of the offset for the reference timing. For example, at 808, the timing offset may be exactly N OFDM symbol durations from the ToA of a given beam. The value of N may also depend on the index of the given beam, in which case a mapping between the beam index and the value N is provided in the information received at the first node from the second node. Thus, the ToA of the given beam is the anchor point from which the reference timing is determined. As described above, this anchor point does not necessarily correspond to the beam with the strongest channel taps, although this is possible. The reference timing may be known at both the first node and the second node, which may be indicated via knowledge of the number "N" together with knowledge of the length of each OFDM symbol duration. For example, the number of OFDM durations (i.e., N) that the positioning beacon is offset from a specified beam (i.e., a given beam) may be explicitly specified by the second node to the first node, or alternatively may be implicitly derived at the first node based on a configuration (e.g., a RACH configuration) sent by the second node to the first node.

[0088] Refer to the following Figure 9-10 describe Figure 8 Various example implementations of the process.

[0089] Reference Fig. 9 , assuming that Figure 7 702-708, Figure 8 802-806 are respectively Figure 7 704-708 of the corresponding. Figure 7 After 708, at 902, the first node 701 selects one of the identified (one or more) beams, and at 904, the first node 701 determines a reference timing (e.g., as Figure 8 At 906, the first node 701 sends a positioning beacon (e.g., as shown in 808) according to the reference timing from 904. Figure 8 Again, in an embodiment, the reference timing may correspond to a transmission time of the positioning beacon that is offset from the arrival time of the selected beam by a given amount (e.g., N OFDM symbol durations, where N is Figure 7 and Fig. 9At 908, the second node 703 receives the location beacon. At 910, the second node 703 calculates a timing metric (e.g., RTT) based in part on the arrival time of the location beacon. Fig. 9 , but timing metrics (e.g., RTT) between the UE and multiple base stations can be calculated and shared with an entity (e.g., a location server that has knowledge of the locations of the base stations), which can then use the timing metrics to estimate the UE's position using multilateration (e.g., trilateration).

[0090] Reference Fig.10 , assuming that Figure 7 702-714, Figure 8 802-806 are respectively Figure 7 704-708 of the corresponding. Figure 7 After receiving the beam report at the second node 703 at 714, at 1002, the second node 703 selects one of the identified (one or more) beams, and at 1004, the second node 703 issues an instruction to the first node 701 to use the selected beam for reference time determination in association with the positioning process. At 1006, the first node 701 receives the instruction from the second node 703. After 1006, the execution is performed as described above. Fig. 9 904-910. Therefore, Fig. 9 represents an example of the first node 701 selecting a beam for which to calculate the reference timing, and Fig.10 This shows an example in which the second node 703 selects a beam for which to calculate reference timing.

[0091] It will be recognized that Figure 7 and Figure 9-10 The location determination process may occur in parallel with the data communication process between the first node and the second node, as described below with respect to Fig.11 The UE may be executed during the start or recovery (e.g., recovery from beam failure, etc.) of a data connection (e.g., when the UE performs a random access procedure with the base station on a random access channel (RACH)). Fig.11 process.

[0092] Reference Fig.11 , assuming that Figure 7 702-704, which can then be executed Figure 7 and / or Figure 9-10 At 1102, in addition to determining the arrival time of each beam (e.g., Figure 7In addition to determining the received signal strength (e.g., RSRP) of each beam at 1102, the first node 701 determines the received signal strength (e.g., RSRP) of each beam at 1102. At 1104, the first node 701 identifies one or more beams to be used in association with a data connection between the first node 701 and the second node 703 based on the received signal strength determined from 1102. The beam(s) identified at 1104 as supporting the data connection may be used in association with the beam(s) identified at 1104. Figure 7 is different from the (one or more) beams identified at 708 as supporting the positioning process. At 1106, the first node 701 determines a reference timing based on one or more arrival times of the identified (one or more) beams from 1104. For example, to determine the reference timing at 1106, the arrival time of the strongest channel tap among the identified (one or more) beams from 1104 can be used, or a function of the arrival times of multiple channel taps can be used. Similar to the reference timing used for positioning beacons, the reference timing used for data connections can correspond to the transmission time of the corresponding data, which is offset from the arrival time of the selected beam by a given amount (e.g., N OFDM symbol durations, where Figure 7 and Fig.11 In contrast to the reference timing used for positioning beacons, the reference timing used for data connections may correspond to the transmission time of the corresponding data, which is offset from the strongest estimated channel tap of the selected beam (rather than ToA) by a given amount (e.g., N OFDM symbol durations, where Figure 7 and Fig.11 Prior to the process of , N is explicitly or implicitly communicated by the second node to the first node.) In one example, if any estimated RTT from the data transmission is not subsequently used for position estimation, then the latter approach (i.e., using the strongest estimated channel tap) may be more advantageous and the formal approach may be unnecessary.

[0093] Reference Fig.11At 1106, in addition to the received signal strength measured at the first node 701 at 1102, the reference timing may be calculated based on information provided from the second node 703. For example, the first node 701 (e.g., UE) may send a RACH preamble transmission, which is received by the second node 703 (e.g., base station). The second node 703 may then calculate a timing adjustment (e.g., timing advance) and send this timing adjustment to the first node 701. The first node 701 may then use the timing adjustment as part of the calculation to determine the reference timing at 1106, i.e., determine the reference timing in conjunction with the arrival time(s) of the identified beam(s). At 1108, the first node 701 sends data to the second node 703 over the data connection according to the reference timing received at the second node 703 at 1110.

[0094] Reference Fig.11 It will be appreciated that the identified beam(s) and / or reference timing for a data connection may differ from Figures 7 to 10 any one of the identified beam(s) and / or reference timing for positioning. Fig.11 Described as Figures 7 to 10 The process is a parallel process, but Fig.11 The process of may also be implemented as a completely separate process (e.g., using a beam different from beams 705-709 that is not used as part of the positioning process). Fig.11 The process illustrates that the criteria for selecting or identifying (one or more) beams (e.g., highest received signal strength or shortest path) can depend on the function to be implemented on the (one or more) corresponding beams (e.g., a positioning process or data transmission).

[0095] Those skilled in the art will recognize that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above specification may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0096] In addition, it will be appreciated by those skilled in the art that the various illustrative logic blocks, modules, circuits and algorithmic steps described in conjunction with the aspects disclosed herein can be implemented as electronic hardware, computer software or a combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits and steps have been generally described above in terms of their functions. Whether this functionality is implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. The technician can implement the described functions in various ways for each specific application, but this implementation decision should not be interpreted as departing from the scope of the various aspects described herein.

[0097] The various illustrative logical blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or other such configurations).

[0098] The methods, sequences and / or algorithms described in conjunction with the aspects disclosed herein may be implemented directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, CD-ROMs, or any other form of non-transitory computer-readable medium known in the art. An exemplary non-transitory computer-readable medium may be coupled to a processor so that the processor can read information from the non-transitory computer-readable medium and write information to the non-transitory computer-readable medium. In an alternative, the non-transitory computer-readable medium may be integrated with the processor. The processor and the non-transitory computer-readable medium may reside in an ASIC. The ASIC may reside in a user device (e.g., UE) or a base station. In an alternative, the processor and the non-transitory computer-readable medium may be discrete components in a user device or a base station.

[0099] 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 on or sent by a non-transitory computer-readable medium as one or more instructions or codes. Computer-readable media may include storage media and / or communication media, and the communication media includes any non-transitory media that can facilitate the transfer of a computer program from one place to another. Storage media can be any available medium that a computer can access. 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), coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (such as infrared, radio and microwave) are all included in the definition of medium. The terms disk and disc, which may be used interchangeably herein, include CDs, laser discs, optical discs, DVDs, floppy disks, and Blu-ray 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.

[0100] Although the foregoing disclosure shows illustrative aspects, those skilled in the art will recognize that various changes and modifications may be made herein without departing from the scope of the present disclosure as defined by the appended claims. In addition, based on the various illustrative aspects described herein, those skilled in the art will recognize that the functions, steps and / or actions in any method described above and / or set forth in any method claim in the appended claims need not be performed in any particular order. Further, with respect to any element described above or set forth in the appended claims in singular form, those skilled in the art will recognize that (one or more) singular forms also encompass the plural unless expressly stated to be limited to (one or more) singular forms.

Claims

1. A method for operating a first node, comprising: receiving, at the first node, a plurality of beams from the second node; determining, by the first node, a time of arrival of each of the plurality of beams; identifying, by the first node, one or more first beams of interest from the plurality of beams for a positioning process based on arrival times of the plurality of beams; determining a first reference timing based on an arrival time of a given beam among the identified one or more first beams of interest; and The first node sends a positioning beacon to the second node according to the first reference timing.

2. The method of claim 1, wherein the location beacon is sent to facilitate calculation of a timing metric at the second node.

3. The method of claim 2, wherein the timing metric is a round trip time (RTT) between the first node and the second node.

4. The method of claim 1, further comprising: determining, by the first node, a received signal strength for each of the plurality of beams or the different plurality of beams; identifying, by the first node, one or more second beams from the plurality of beams or the different plurality of beams based on the determined received signal strength, the one or more second beams to be used in association with a data connection between the first node and the second node; determining a second reference timing based on the one or more times of arrival of the identified one or more second beams; and The first node sends data to the second node through the data connection according to the second reference timing.

5. The method of claim 1, wherein the identified one or more first beams of interest correspond to one or more beams having one or more earliest arrival times among the plurality of beams.

6. The method of claim 1, wherein the given beam is a beam associated with an earliest arrival time among the plurality of beams.

7. The method according to claim 6, wherein each beam of the plurality of beams is associated with a set of channel taps detected at the first node, and The given beam corresponds to a beam having an earliest channel tap in its corresponding set of channel taps among the plurality of beams.

8. The method of claim 1, further comprising: issuing, by the first node to the second node, a report indicating each of the identified one or more first beams of interest; and In response to the report, an instruction is received at the first node from the second node to determine a first reference timing using the given beam.

9. The method of claim 1, wherein the given beam is received on a shortest path from a first node to a second node.

10. The method according to claim 9, wherein the shortest path corresponds to a line-of-sight (LOS) path, or The shortest path corresponds to a non-LOS NLOS path.

11. The method of claim 1, wherein at least one beam among the plurality of beams other than the given beam has a higher received signal strength at the first node relative to a received signal strength of the given beam.

12. The method of claim 1, wherein each beam of the plurality of beams arrives at the first node at a different angle of arrival (AoA).

13. The method of claim 1, wherein the first node receives the plurality of beams on an Extremely High Frequency (EHF) band. The method of claim 13 , wherein the EHF band comprises a millimeter wave (mmW) band.

15. The method of claim 1, wherein each beam of the plurality of beams carries a synchronization signal for a second node.

16. The method of claim 1, wherein the first node is a user equipment and the second node is a base station or an antenna or an antenna array of a base station.

17. The method of claim 1, wherein the first node is a base station or an antenna or an antenna array of a base station, and the second node is a user equipment.

18. The method of claim 1, further comprising: receiving, from the second node, information indicating a timing offset for the first reference timing, The first reference timing corresponds to the time when the first node sends the positioning beacon, and Wherein the first reference timing is offset from the arrival time of the given beam by the timing offset.

19. The method of claim 18, wherein the received information indicates the timing offset via an explicit indication of a number of OFDM symbol durations, or Wherein the received information implicitly indicates the timing offset via an indication of a configuration from which the first node derives the timing offset.

20. A first node, comprising: means for receiving a plurality of beams from a second node; means for determining a time of arrival of each of the plurality of beams; means for identifying one or more first beams of interest from the plurality of beams for use in a positioning procedure based on arrival times of the plurality of beams; means for determining a first reference timing based on a time of arrival of a given beam among the identified one or more first beams of interest; as well as Means for sending a positioning beacon to a second node based on the first reference timing.

21. The first node of claim 20, wherein the identified one or more first beams of interest correspond to one or more beams having earliest arrival times among the plurality of beams.

22. The first node of claim 20, wherein the given beam is a beam associated with an earliest arrival time among the plurality of beams.

23. The first node of claim 20, wherein the given beam is received on a shortest path from the first node to the second node.

24. A first node, comprising: Memory; as well as at least one processor coupled to the memory and the communication interface, the at least one processor configured to: receiving a plurality of beams from a second node; determining a time of arrival of each of the plurality of beams; identifying one or more first beams of interest from the plurality of beams for use in a positioning process based on arrival times of the plurality of beams; determining a first reference timing based on an arrival time of a given beam among the identified one or more first beams of interest; and A positioning beacon is sent to the second node according to the first reference timing.

25. The first node of claim 24, wherein the identified one or more first beams of interest correspond to one or more beams having one or more earliest arrival times among the plurality of beams.

26. The first node of claim 24, wherein the given beam is a beam associated with an earliest arrival time among the plurality of beams.

27. The first node of claim 24, wherein the given beam is received on a shortest path from the first node to the second node.

28. A non-transitory computer-readable medium comprising instructions stored thereon, the instructions, when executed by a first node, causing the first node to perform operations, the instructions comprising: at least one instruction configured to cause the first node to receive a plurality of beams from the second node; at least one instruction configured to cause the first node to determine a time of arrival of each of the plurality of beams; at least one instruction configured to cause the first node to identify one or more first beams of interest from the plurality of beams for a positioning process based on arrival times of the plurality of beams; at least one instruction configured to cause the first node to determine a first reference timing based on a time of arrival of a given beam among the identified one or more first beams of interest; as well as The method is configured to enable the first node to send at least one instruction of a positioning beacon to the second node according to the first reference timing.

29. The non-transitory computer readable medium of claim 28, wherein the identified one or more first beams of interest correspond to one or more beams having one or more earliest arrival times among the plurality of beams, and / or The given beam is a beam associated with an earliest arrival time among the plurality of beams.

30. The non-transitory computer-readable medium of claim 28, wherein the given beam is received on a shortest path from a first node to a second node.

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