Apparatus and method of multi-path mitigation using a time-division architecture of a global navigation satellite system receiver

Abstract

According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include a global navigation satellite system (GNSS) receiver. The GNSS receiver may be configured to obtain a plurality of GNSS signals over a measurement cycle. The GNSS receiver may be configured to implement a time-division signal blanking mechanism to identify line-of-sight (LOS)-only signals received during the measurement cycle.

Description

APPARATUS AND METHOD OF MULTI-PATH MITIGATION USING A TIME-DIVISION ARCHITECTURE OF A GLOBAL NAVIGATION SATELLITE SYSTEM RECEIVERBACKGROUND

[0001] Embodiments of the present disclosure relate to apparatus and method for wireless communication.

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. In wireless local area network (WLAN) communication (e.g., such as Wi-Fi) and in cellular communication (e.g., such as the 4th-generation (4G) Long Term Evolution (LTE) and the 5th-generation (5G) New Radio (NR)), the Institute of Electrical and Electronics Engineers (IEEE) and the 3rd Generation Partnership Project (3 GPP) define various operations for global navigation satellite system (GNSS) navigation.SUMMARY

[0003] According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include a GNSS receiver. The GNSS receiver may be configured to obtain a plurality of GNSS signals over a measurement cycle. The GNSS receiver may be configured to implement a time-division signal blanking mechanism to identify line-of-sight (LOS)-only signals received during the measurement cycle.

[0004] According to another aspect of the present disclosure, an apparatus for wireless communication is provided. The apparatus may include a communication interface and a GNSS receiver. The communication interface may be configured to receive a plurality of GNSS signals over a measurement cycle. The GNSS receiver may be configured to obtain the plurality of GNSS signals over the measurement cycle. The GNSS receiver may be configured to implement a timedivision signal blanking mechanism to identify LOS-only signals received during the measurement cycle.

[0005] According to a further aspect of the present disclosure, a method of wireless communication of a user equipment is provided. The method may include obtaining, by a GNSS receiver, a plurality of GNSS signals over a measurement cycle. The method may include implementing, by the GNSS receiver, a time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle.

[0006] These illustrative embodiments are mentioned not to limit or define the present disclosure, but to provide examples to aid understanding thereof. Additional embodiments are discussed in the Detailed Description, and further description is provided there.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable a person skilled in the pertinent art to make and use the present disclosure.

[0008] FIG. 1 illustrates a diagram of various GNSS signal conditions as a GNSS receiver travels through an urban canyon.

[0009] FIG. 2 illustrates an exemplary wireless network, according to some embodiments of the present disclosure.

[0010] FIG. 3 illustrates a block diagram of an exemplary node, according to some embodiments of the present disclosure.

[0011] FIG. 4 illustrates a block diagram of an apparatus including a GNSS receiver, a wireless network interface, and a host chip, according to some embodiments of the present disclosure.

[0012] FIG. 5 illustrates a diagram of an exemplary time-division architecture of the GNSS receiver of FIG. 4, according to some embodiments of the present disclosure.

[0013] FIG. 6 illustrates a flowchart of an exemplary method for wireless communication, according to some embodiments of the present disclosure.

[0014] Embodiments of the present disclosure will be described with reference to the accompanying drawings.DETAILED DESCRIPTION

[0015] Although specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to a person skilled in the pertinent art thatthe present disclosure can also be employed in a variety of other applications.

[0016] It is noted that references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of a person skilled in the pertinent art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0017] In general, terminology may be understood at least in part from usage in context. For example, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0018] Various aspects of wireless communication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0019] The techniques described herein may be used for various wireless communication networks, such as code division multiple access (CDMA) system, time division multiple access (TDMA) system, frequency division multiple access (FDMA) system, orthogonal frequency division multiple access (OFDMA) system, single-carrier frequency division multiple access (SC- FDMA) system, wireless local area network (WLAN) system, a global navigation satellites system(GNSS), and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio access technology (RAT), such as Universal Terrestrial Radio Access (UTRA), evolved UTRA (E-UTRA), CDMA 2000, etc. A TDMA network may implement a RAT, such as the Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT, such as LTE or NR. A WLAN system may implement a RAT, such as Wi-Fi. The techniques described herein may be used for the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0020] GNSS is frequently used for positioning services in various applications, such as pedestrian and vehicular navigation. To accurately determine its position, a user equipment (UE) or station (STA) is generally equipped with a GNSS receiver. The GNSS receiver uses the time difference between the time a signal is received versus when the signal was broadcast by a satellite vehicle (SV) to determine the receiver’s distance from the SV. A GNSS receiver that receives signals from four SVs can determine its position in three dimensions (3D). Three of the SVs are used to determine latitude, longitude, and height, while a fourth SV is set to synchronize the receiver’s internal clock.

[0021] Multi-path in GNSS refers to the phenomenon when the SV signals are reflected before reaching the GNSS receiver. Such reflections can cause significant errors in position estimation. Position estimation in an urban environment (also referred to herein as an “urban canyon”) is particularly prone to inaccuracies due to multi-path. Identifying and reducing the effect of multi-path would enable GNSS to be a primary component of high integrity railway control, autonomous vehicle operating in urban environments, or a user navigating through a downtown area with skyscrapers. Many studies have been conducted on GNSS multi-path detection and mitigation. A multi-antenna system using a set of five antennas was proposed to estimate and remove multi-path error based on the spatial correlation of received signals; but this type of system is expensive and large in size, which makes it difficult to be implemented in commercial handheld devices or even ground vehicles. A multi-path detection technique based on satellite exclusion was introduced using an upward-viewing infrared camera to identify the open sky. Satellite signals that are blocked by one or more obstacles (such as buildings), thus resulting in non-line-of-sight (NLOS) signals, were discarded when calculating position solutions. However, this approach cannot reliably detect the case when both the line-of-sight (LOS) signal and the reflected NLOS signals arrive at the GNSS receiver.

[0022] The quality of GNSS signals is usually degraded by multi-path phenomena whenthe GNSS receiver moves close to high-rise buildings or skyscrapers, e.g., namely, when the GNSS receiver travels through an urban canyon. FIG. 1 illustrates a diagram 100 of various GNSS signal conditions experienced by a GNSS receiver as it travels through an urban canyon. When moving through such environment, the received GNSS signals from a GNSS SV can be one of the following: 1) the received GNSS signals are completely blocked by the building (not shown), 2) the received GNSS signal(s) contains both the LOS and non-LOS component 102a, 3) the received GNSS signal(s) contain only the non-LOS components 102b, and 4) the received GNSS signal(s) may include only the LOS component 102c. Within the observation of one second, the GNSS receiver experiences all four of the above-mentioned signal conditions. In addition to LOS and non-LOS, a third type of propagation, near-line-of-sight (NLOS), can be categorized into either the LOS type or non-LOS type, in accordance with various embodiments.

[0023] Except for the case where the GNSS signal is completely blocked, in general, under the moving scenario in FIG. 1, there is a Doppler offset of at least a few Hertz (Hz) between the LOS and non-LOS path. The distance measurement when the signal with only the LOS component 102c is always smaller than the distance measurement when the signal is corrupted by the non- LOS component 102a and 102b. For example, referring to FIG. 1, the quality of distance measurement using all the samples from the antenna for the entire one second may not be as good as the one just using the samples in the regions (e.g., cross-hatched) in which only the LOS component 102c is observed because those samples are the ones not impacted by the multi-path or non-LOS component.

[0024] However, because existing GNSS receivers are unable to identify which component includes only the LOS component (e.g., LOS component 102c), these receivers are unable to identify which components to ignore to determine the best position measurement result.

[0025] To overcome these and other challenges, the present disclosure provides an exemplary GNSS receiver with a time-division receiving architecture, which enables the identification of a LOS-only component when moving through an urban canyon. To that end, the GNSS receiver of the present disclosure estimates a plurality of distance measurements (i.e., GNSS measurements) during different segments of a measurement cycle. This operation may begin when the GNSS receiver detects that it is moving through an urban canyon. The GNSS receiver may identify when its moving through an urban canyon based on the differences in distance measurements in successive segments of a measurement cycle. When this happens, the distance blanking component of the GNSS receiver may identify which segment of the measurement cyclehas the smallest value, which is the value that matches the LOS-only component. The blanking pattern that matches this value may be used to blank out the other components that include non- LOS signals and / or the components that block all GNSS signals completely. Based upon the blanking pattern, the exemplary GNSS receiver may be able to identify its position based on the LOS-only component with a higher degree of accuracy compared to known GNSS receivers. The distance measurement includes, but is not limited to, code phase measurement and carrier phase measurement. Additional details of the exemplary GNSS receiver and its operations are provided below in connection with FIGs. 2-6.

[0026] Although some embodiments are described herein in connection with a WLAN or GNSS communication system, the same or similar techniques may be applied to a cellular communication system, as well. For example, a UE that receives a signal from a 5G NR base station via beamforming and / or millimeter-wave (mmW) signaling may experience multi-path issues as these beams may reflect off nearby objects, which can deteriorate the accuracy of positioning determination using these signals. Thus, the techniques described below may apply to estimating a set of beam parameters for use in positioning determination by a UE in a cellular communication system without departing from the scope of the present disclosure.

[0027] As used herein, the term “LOS-only signals” may refer to a virtual channel in which most of all of the NLOS signals are blanked out. Using the LOS-only signals, a position of the exemplary GNSS receiver may be estimated with a higher degree of accuracy than if the timedivision mechanism described below is not implemented.

[0028] FIG. 2 shows a simplified architecture of a wireless communication system 200 in accordance with certain embodiments presented herein. System 200 may include non-access point (AP) stations (STAs) such as user equipments (UEs) 220-1 through 220-w (collectively referred to as UEs 220), and AP STAs such as APs 240-1 through 240-4 (collectively referred to as APs 240), which may communicate over a wireless communication network 230. Examples of UEs 220 may include, e.g., smartphones, vehicles, wearable devices, laptops, or any other device that can provide a navigation function to a user. In some embodiments, wireless communication network 230 may take the form of and / or may include one or more wireless local area networks (WLANs) or the internet. In some embodiments, UEs 220 and / or APs 240 may communicate with server 250 via wireless communication network 230. While system 200 illustrates some UEs 220 and APs 240, the number of UEs 220 and APs 240 in a wireless communication network (e.g., a WLAN) may be varied in accordance with various system parameters. In general, system 200 may include asmaller or larger number of UEs 220 and / or APs 240.

[0029] In some embodiments, as outlined above, UE 220 may include a GNSS receiver configured to receive, measure and decode signals from one or more satellite vehicles (SVs) 280- 1 through 280-4 and thereby obtain a position fix, an accurate absolute time reference (such as global positioning system (GPS) time, Coordinated Universal Time (UTC) or a time for another GNSS which may be accurate to 50 nanoseconds (ns) or better in some embodiments) and a timing reference uncertainty. UE position information may be estimated using the GNSS signals broadcast by the SVs 280, a 3D virtual map obtained from server 250, and the use of the exemplary multi-path mitigation technique described below. The position information may be used for navigation and / or provided to APs 240, which use the information to identify a timing reference.

[0030] For example, the GNSS position fix, absolute time reference and / or absolute time synchronization information (e.g., GPS time, GNSS time, or UTC time), and timing reference uncertainty may be provided (e.g., by one or more UEs 220) to APs 240 by sending signaling information to APs 240 that includes a time reference such as using, for example, the Internet Network Time Protocol (NTP), IEEE 1588 Precision Time Protocol (PTP) and / or Synchronous Ethernet. In some embodiments, APs 240, which receive the position fix, absolute time reference, and time reference uncertainty information, may optionally modify the time reference uncertainty information to account for other inaccuracies and / or processing delays. In some embodiments, the absolute time and time reference uncertainty information may be modified by APs 240 based on the distance of UE 220 from AP 240, which may be determined from the position fix. For example, APs 240 may modify time reference uncertainty to adjust for Short Interframe Spacing (SIFS) delays, if appropriate. The terms “SIFS interval” or “SIFS delay” may refer to the amount of time (e.g., in microseconds) it takes for a wireless interface to process a received frame and to respond with a response frame. A SIFS interval may consist of the time delay arising from receiver radio frequency (RF) processing, Physical Layer Convergence Procedure (PLCP) delay, and the Medium Access Control (MAC) processing delay, which may depend on the physical layer used.

[0031] In some embodiments, APs 240 and / or UEs 220 that are synchronized to or have access to a common time reference may transmit or re-transmit (unicast, multicast, or broadcast) the common time reference and time reference uncertainty to other STAs or devices on network 230. For example, an AP 240 synchronized to an absolute timing reference may transmit the timing reference and timing uncertainty information to other devices. As another example, a UE 220 may demodulate the Time-Of-Week (TOW) header to obtain an absolute (e.g., GNSS)time reference. In some embodiments, UE 220 may send the absolute time reference and timing reference uncertainty to one or more APs 240. Further, the timing reference and timing uncertainty may be requested by and / or provided to one or more UEs 220 that do not have access to the absolute timing reference source.

[0032] In instances where one or more APs 240 experience clock degradation, maintaining timing synchronization by APs 240 may be facilitated by the timing information received by the APs 240 from UEs 220. In some embodiments, APs 240 may use the absolute time reference (e.g., GNSS time) for measurements and / or time stamps. For example, packets or frames sent or received by APs 240 may be timestamped using the absolute time reference. In some embodiments, multiple APs 240 on network 230 may be synchronized to a common absolute time reference (e.g., to GNSS time) via timing information received from UEs 220 to obtain a quasi-synchronous network.

[0033] In some embodiments, one or more UEs 220 and / or APs 240 in system 200 may comprise multiple antennas and may support multiple-input multiple-output (MIMO) and / or multiuser MIMO (MU-MIMO). UE 220 may receive and measure signals from APs 240, which may be used for position determination. In some embodiments, APs 240 may form part of a wireless communication network 230, such as a WLAN. For example, a WLAN may be an IEEE 802.1 lx network (e.g., such as IEEE 802.1 lax, 802.1 lay, or a later version). Further, system 200 may comprise or take the form of an Extended Service Set (ESS) network, which may comprise a plurality of appropriately configured basic service set (BSS) networks, an Independent Basic Service Set (IBSS) network, an ad-hoc network, or a peer-to-peer (P2P) network (e.g., operating according to Wi-Fi Direct or similar protocols).

[0034] In some embodiments, one or more UEs 220 and APs 240 may communicate over wireless communication network 230, which may be based on IEEE 802.11 or compatible standards. In some embodiments, UEs 220 and APs 240 may communicate using variants of the IEEE 802.11 standards. For example, UEs 220 and APs 240 may communicate using 802.1 lac on the 5 GHz band, which may support multiple spatial streams including MIMO and MU-MIMO. In some embodiments, UEs 220 and APs 240 may communicate using some of the above standards, which may further support one or more of Very High Throughput (VHT) (as described in the above standards) and High -Efficiency WLAN (HEW), and / or beamforming with standardized sounding and feedback mechanisms. In some embodiments, UEs 220 and or APs 240 may additionally support legacy standards for communication with legacy devices.

[0035] In some embodiments, UEs 220 and / or APs 240 may be coupled to one or moreadditional networks, such as a cellular carrier network, a satellite positioning network (shown in FIG. 2), wireless personal area network (WPAN) access points, and the like (not shown in FIG. 2). In some embodiments, UEs 220 and / or APs 240 may be coupled to a wireless wide area network (WWAN) (not shown in FIG. 2), A WWAN may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency Division Multiple Access (OFDMA) network, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) network, Long Term Evolution (LTE), 5G new radio (NR), WiMax, and so on.

[0036] Still referring to FIG. 2, in some embodiments, any suitable node of wireless communication system 200, such as UE 220, may include the exemplary GNSS receiver described herein, which is designed with a time-division receiving architecture. The time-division architecture may enable UE 220 to identify a LOS-only component when moving through an urban canyon.

[0037] Each element in FIG. 2 may be considered a node of wireless communication system 200. More detail regarding the possible implementation of a node is provided by way of example in the description of a node 300 in FIG. 3. Node 300 may be configured as UE 220, AP 240, or server 250 in FIG. 2. As shown in FIG. 3, node 300 may include a processor 302, a memory 304, and a transceiver 306. These components are shown as connected to one another by a bus, but other connection types are also permitted. When node 300 is UE 220, additional components may also be included, such as a user interface (UI), sensors, and the like. Similarly, node 300 may be implemented as a blade in a server system when node 300 is configured as server 250. Other implementations are also possible.

[0038] Transceiver 306 may include any suitable device for sending and / or receiving data. Node 300 may include one or more transceivers, although only one transceiver 306 is shown for simplicity of illustration. An antenna 308 is shown as a possible communication mechanism for node 300. Multiple antennas and / or arrays of antennas may be utilized for receiving multiple spatially multiplex data streams. Additionally, examples of node 300 may communicate using wired techniques rather than (or in addition to) wireless techniques. For example, AP 240 may communicate wirelessly to UE 220 and may communicate by a wired connection (for example, by optical or coaxial cable) to server 250. Other communication hardware, such as a network interface card (NIC), may be included as well.

[0039] As shown in FIG. 3, node 300 may include processor 302. Although only oneprocessor is shown, it is understood that multiple processors can be included. Processor 302 may include microprocessors, microcontroller units (MCUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. Processor 302 may be a hardware device having one or more processing cores. Processor 302 may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software can include computer instructions written in an interpreted language, a compiled language, or machine code. Other techniques for instructing hardware are also permitted under the broad category of software.

[0040] As shown in FIG. 3, node 300 may also include memory 304. Although only one memory is shown, it is understood that multiple memories can be included. Memory 304 can broadly include both memory and storage. For example, memory 304 may include random-access memory (RAM), read-only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM), compact disc read only memory (CD-ROM) or other optical disk storage, hard disk drive (HDD), such as magnetic disk storage or other magnetic storage devices, Flash drive, solid-state drive (SSD), or any other medium that can be used to carry or store desired program code in the form of instructions that can be accessed and executed by processor 302. Broadly, memory 304 may be embodied by any computer-readable medium, such as a non-transitory computer-readable medium.

[0041] Processor 302, memory 304, and transceiver 306 may be implemented in various forms in node 300 for performing wireless communication functions. In some embodiments, processor 302, memory 304, and transceiver 306 of node 300 are implemented (e.g., integrated) on one or more system-on-chips (SoCs). In one example, processor 302 and memory 304 may be integrated on an application processor (AP) SoC (sometimes known as a “host,” referred to herein as a “host chip”) that handles application processing in an operating system (OS) environment, including generating raw data to be transmitted. In another example, processor 302 and memory 304 may be integrated on a baseband processor (BP) SoC (sometimes known as a “modem,” referred to herein as a “radio”) that converts the raw data, e.g., from the host chip, to signals thatcan be used to modulate the carrier frequency for transmission, and vice versa, which can run a real-time operating system (RTOS). In still another example, processor 302 and transceiver 306 (and memory 304 in some cases) may be integrated on an RF SoC (sometimes known as a “transceiver,” referred to herein as a “wireless network interface”) that transmits and receives RF signals with antenna 308. It is understood that in some examples, some or all of the host chip, radio, and wireless network interface may be integrated as a single SoC. For example, a radio and a wireless network interface may be integrated into a single SoC that manages all the radio functions for GNSS communication, WLAN communication, WPAN communication, and / or cellular communication.

[0042] FIG. 4 illustrates a block diagram of an apparatus 400 including a GNSS receiver 402, a wireless network interface 404, and a host chip 406, according to some embodiments of the present disclosure. Apparatus 400 may be implemented as UE 220 of wireless communication system 200 in FIG. 2. In some embodiments, GNSS receiver 402 is implemented by processor 302 and memory 304, and wireless network interface 404 is implemented by processor 302, memory 304, and transceiver 306, as described above with respect to FIG. 3. When used for positioning determination within a WLAN communication system, GNSS receiver 402 may be implemented as a WLAN radio or communication chip. On the other hand, when used for positioning determination within a GNSS communication system, GNSS receiver 402 may be implemented as a GNSS receiver radio. Still further, when used for positioning determination within a cellular communication system, GNSS receiver 402 may be implemented as a baseband chip, and wireless network interface 404 may be implemented as an RF chip.

[0043] Besides the on-chip memory 418 (also known as “internal memory,” e.g., registers, buffers, or caches) on GNSS receiver 402, wireless network interface 404, or host chip 406, apparatus 400 may further include an external memory 408 (e.g., the system memory or main memory) that can be shared by GNSS receiver 402, wireless network interface 404, or host chip 406 through the system / main bus. Although GNSS receiver 402 is illustrated as a standalone SoC in FIG. 4, it is understood that in one example, GNSS receiver 402 and wireless network interface 404 may be integrated as one SoC; in another example, GNSS receiver 402 and host chip 406 may be integrated as one SoC; in still another example, GNSS receiver 402, wireless network interface 404, and host chip 406 may be integrated as one SoC, as described above.

[0044] In the uplink, host chip 406 may generate raw data and send it to GNSS receiver 402 for encoding, modulation, and mapping. Interface 414 of GNSS receiver 402 may receive thedata from host chip 406. GNSS receiver 402 may also access the raw data generated by host chip 406 and stored in external memory 408, for example, using the direct memory access (DMA). GNSS receiver 402 may first encode (e.g., by source coding and / or channel coding) the raw data and modulate the coded data using any suitable modulation techniques, such as multi-phase shift keying (MPSK) modulation or quadrature amplitude modulation (QAM). GNSS receiver 402 may perform any other functions, such as symbol or layer mapping, to convert the raw data into a signal that can be used to modulate the carrier frequency for transmission. In the uplink, GNSS receiver 402 may send the modulated signal to wireless network interface 404 via interface 414. Wireless network interface 404, through a transmitter (TX) 450, may convert the modulated signal in the digital form into analog signals, i.e., RF signals, and perform any suitable front-end RF functions, such as filtering, digital pre-distortion, up-conversion, or sample-rate conversion. Antenna array 410 may transmit the RF signals provided by TX 450 of wireless network interface 404.

[0045] In the downlink, antenna array 410 may receive GNSS signals from one or more SVs, for example. The GNSS signals may include one or more LOS signals and / or NLOS signals. The GNSS signals may be passed to a receiver (RX) 440 of wireless network interface 404. Wireless network interface 404 may perform any suitable front-end RF functions, such as filtering, IQ imbalance compensation, down-paging conversion, or sample-rate conversion, and convert the RF signals (e.g., transmission) into low-frequency digital signals (baseband signals) that can be processed by GNSS receiver 402. Wireless network interface 404 (e.g., a communication interface) may be configured to receive a plurality of GNSS signals from four or more GNSS SVs. These GNSS signals may be passed to GNSS receiver 402.

[0046] As seen in FIG. 4, GNSS receiver 402 may be designed with a time-division receiving architecture (e.g., time-division component 420). GNSS receiver 402 may be configured to identify a LOS-only component when it moves through an urban canyon. When GNSS receiver 402 identifies the received signal may be corrupted by multi-path (e.g., by looking at the range residual error, etc.) and that the device is moving (e.g., this detection may be performed using one or more motion sensors), GNSS receiver 402 may activate time-division component 420. The range residual error varies depending on the application scenario. For instance, for mobile devices, the range residual error is limited to approximately 30 meters, as differences greater than this value do not meet the usage requirements. In some embodiments, a threshold of the movement of a mobile device is about five meters-per-second (5MPS) by tracking progress about every 30 seconds. If a speed is smaller than 5MPS, GNSS receiver 402 may not activate or may stopactivating time-division component 420. However, the threshold of the movement or the tracking time-period can by slightly adjusted for various application scenarios. Time-division component 420 may be configured to implement a time-division signal blanking mechanism to identify LOS- only signals received during the measurement cycle. Based on the LOS-only signals identified by the time-division component 420, position estimation component 422 may be configured to estimate a position of GNSS receiver 402 as it moves through an urban canyon environment. Additional details of time-division component 420 and the exemplary operations of GNSS receiver 402 are provided below in connection with FIG. 5.

[0047] FIG. 5 illustrates a diagram 500 of an exemplary time-division architecture of GNSS receiver 402 of FIG. 4, according to some embodiments of the present disclosure. Referring to FIG. 5, a detailed block diagram of GNSS receiver 402 and wireless network interface 404 of apparatus 400 is shown. For instance, wireless network interface 404 may include, e.g., an RF circuit 502, an analog-to-digital converter (ADC) 504, and a signal filter 506. GNSS receiver 402 may include, e.g., a plurality of correlators 508a, 508b...508n (e.g., a first correlator 508a, a second correlator 508b...an nthcorrelator 508n), a blanking pattern generation component 510, and a measurement selection component 512.

[0048] As previously mentioned, under the moving condition, the distance measurement of the LOS-only component of a measurement cycle is always smaller than the distance measurement from the signal corrupted by multi-path. Thus, time-division component 420 is configured to generate a plurality of blanking patterns that are used to blank a plurality of virtual channels, each of which is associated with a different segment of the measurement cycle. Then, the blanking pattern that matches with the LOS-only segment(s) will produce the best measurement and its distance measurement is also the smallest. By identifying the virtual channel with the smallest code phase, measurement selection component 512 may identify which virtual channel to use for position measurement. Measurement selection component 512 may output the LOS-only signals to, e.g., position estimation component 422. As mentioned above, in some embodiments when no LOS-only component is identified, the NLOS component is considered to be selected for subsequent process.

[0049] For example, at the beginning of each measurement cycle, e.g., one second, GNSS receiver 402 creates a set of virtual channels using samples from some non-blanked windows while blanking the remaining N samples. For example, GNSS receiver 402 may create ten virtual channels (e.g., N for the one-second observation period). Thus, blanking pattern generationcomponent 510 may generate ten blanking patterns (e.g., an / W number of blanking patterns). Each of the N blanking patterns may be sent to a different correlator 508. In this example, the first channel may include samples from millisecond 0 to millisecond 199, the second channel may include samples from millisecond 100 to millisecond 299, ..., and the tenth channel may include samples from millisecond 800 to millisecond 999. For each of the segments, blanking pattern generation component 510 may generate a blanking pattern, which blanks out certain portions of its associated segment of the measurement cycles. Each of the different blanking patterns may be sent to one of the correlators 508. In some embodiments, within the one-second observation period, the number of N ranges from 2 to 10. If the number of / Vis greater than 10, signal energy is divided into one or more portions, resulting in reduced energy for each channel and increased storage / memory requirement, in some instances. If the number of N is smaller than 2, there’s no difference from the other approaches. Then, each correlator may apply the blanking pattern to its virtual channel to identify a distance measurement. The distance measurements may each be sent to measurement selection component 512. Measurement selection component 512 may identify the virtual channel with the smallest distance measurement as the virtual channel that captures the LOS-only signals. The virtual channel with the smallest code phase may be selected and reported to the higher processing layer. Using the signal information in the selected virtual channel, GNSS receiver 402 (e.g., position estimation component 422) may estimate its position within the urban canyon with a higher degree of accuracy than using a channel that includes non-LOS signals.

[0050] FIG. 6 illustrates a flowchart of an exemplary method 600 of wireless communication, according to embodiments of the disclosure. Exemplary method 600 may be performed by a wireless device, e.g., such as UE 220, node 300, apparatus 400, GNSS receiver 402, time-division component 420, a set of correlators 508, blanking pattern generation component 510, and / or measurement selection component 512, just to name a few. Method 600 may include steps 602-608, as described below. It is to be appreciated that some of the steps may be optional (e.g., dashed lines), and some of the steps may be performed simultaneously, or in a different order than shown in FIG. 6.

[0051] Referring to FIG. 6, at 602, the wireless device may activate a time-division component in response to identifying the GNSS receiver moves through the urban canyon environment. For example, referring to FIG. 4, 2hen GNSS receiver 402 identifies the received signal may be corrupted by multi-path (e.g., by looking at the range residual error, etc.) and that the device is moving (e.g., this detection may be performed using one or more motion sensor),GNSS receiver 402 may activate time-division component 420. Time-division component 420 may be configured to implement a time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle.

[0052] At 604, the wireless device may obtain a plurality of GNSS signals. For example, referring to FIG. 4, wireless network interface 404 (e.g., a communication interface) may be configured to receive a plurality of GNSS signals from four or more GNSS SVs. These GNSS signals may be passed to GNSS receiver 402.

[0053] At 606, the wireless device may implement a time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle. For example, referring to FIG. 5, under the moving condition, the distance measurement of the LOS-only component of a measurement cycle is always smaller than the distance measurement from the signal corrupted by multi-path. Thus, time-division component 420 is configured to generate a plurality of blanking patterns that are used to blank a plurality of virtual channels, each of which is associated with a different segment of the measurement cycle. Then, the blanking pattern that matches with the LOS-only segment(s) will produce the best measurement, and its distance measurement is also the smallest. By identifying the virtual channel with the smallest code phase, measurement selection component 512 may identify which virtual channel to use for position measurement. For example, at the beginning of each measurement cycle, e.g., one second, GNSS receiver 402 creates a set of virtual channels using samples from some non-blanked windows while blanking the remaining N samples. For example, GNSS receiver 402 may create ten virtual channels (e.g., N for the one-second observation period. Thus, blanking pattern generation component 510 may generate ten blanking patterns (e.g., an AT number of blanking patterns). Each of the N blanking patterns may be sent to a different correlator 508. In this example, the first channel may include samples from millisecond 0 to millisecond 199, the second channel may include samples from millisecond 100 to millisecond 299, and the tenth channel may include samples from millisecond 800 to millisecond 999. For each of the segments, blanking pattern generation component 510 may generate a blanking pattern, which blanks out certain portions of its associated segment of the measurement cycles. Each of the different blanking patterns may be sent to one of the correlators 508. Then, each correlator may apply the blanking pattern to its virtual channel to identify a distance measurement. The distance measurements may each be sent to measurement selection component 512. Measurement selection component 512 may identify the virtual channel with the smallest distance measurement as the virtual channel that captures theLOS-only signals. The virtual channel with the smallest code phase may be selected and reported to the higher processing layer.

[0054] At 608, the wireless device may estimate the position of the GNSS receiver based on the LOS-only signals. For example, referring to FIGs. 4 and 5, using the signal information in the selected virtual channel, GNSS receiver 402 (e.g., position estimation component 422) may estimate its position within the urban canyon with a higher degree of accuracy than using a channel that includes non-LOS signals.

[0055] In various aspects of the present disclosure, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as instructions or code on a non-transitory computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computing device, such as node 300 in FIG. 3. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, Flash drive, SSD, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a processing system, such as a mobile device or a computer. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital video disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0056] According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include a GNSS receiver. The GNSS receiver may be configured to obtain a plurality of GNSS signals over a measurement cycle. The GNSS receiver may be configured to implement a time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle.

[0057] In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to generate a plurality of blanking patterns. In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to obtain a plurality of virtual channels by applying each of the plurality of blanking patterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle. In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to identify a LOS-only virtual channel from the plurality ofvirtual channels.

[0058] In some embodiments, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver may be configured to compare a distance measurement associated with each of the plurality of virtual channels. In some embodiments, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver may be configured to identify the plurality of virtual channels with a lowest distance measurement as the LOS-only virtual channel.

[0059] In some embodiments, the GNSS receiver may be further configured to perform position estimation based on the LOS-only virtual channel.

[0060] In some embodiments, the GNSS receiver may be further configured to identify that the GNSS receiver is moving through an urban canyon environment.

[0061] In some embodiments, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver may be configured to determine that a range residual error associated with GNSS signal measurement meets a first threshold value. In some embodiments, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver may be configured to determine that the GNSS receiver when a motion sensor measurement meets a second threshold value.

[0062] In some embodiments, the GNSS receiver may be further configured to, in response to identifying the GNSS receiver is moving through the urban canyon environment, activate a timedivision component to implement the time-division signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

[0063] According to another aspect of the present disclosure, an apparatus for wireless communication is provided. The apparatus may include a communication interface and a GNSS receiver. The communication interface may be configured to receive a plurality of GNSS signals over a measurement cycle. The GNSS receiver may be configured to obtain the plurality of GNSS signals over the measurement cycle. The GNSS receiver may be configured to implement a timedivision signal blanking mechanism to identify LOS-only signals received during the measurement cycle.

[0064] In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to generate a plurality of blanking patterns. In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to obtain a plurality of virtual channels by applying each of the plurality of blankingpatterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle. In some embodiments, to implement the time-division signal blanking mechanism, the GNSS receiver may be configured to identify a LOS-only virtual channel from the plurality of virtual channels.

[0065] In some embodiments, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver may be configured to compare a distance measurement associated with each of the plurality of virtual channels. In some embodiments, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver may be configured to identify the plurality of virtual channels with a lowest distance measurement as the LOS-only virtual channel.

[0066] In some embodiments, the GNSS receiver may be further configured to perform position estimation based on the LOS-only virtual channel.

[0067] In some embodiments, the GNSS receiver may be further configured to identify that the GNSS receiver is moving through an urban canyon environment.

[0068] In some embodiments, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver may be configured to determine that a range residual error associated with GNSS signal measurement meets a first threshold value. In some embodiments, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver may be configured to determine that the GNSS receiver when a motion sensor measurement meets a second threshold value.

[0069] In some embodiments, the GNSS receiver may be further configured to, in response to identifying the GNSS receiver is moving through the urban canyon environment, activate a timedivision component to implement the time-division signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

[0070] According to a further aspect of the present disclosure, a method of wireless communication of a user equipment is provided. The method may include obtaining, by a GNSS receiver, a plurality of GNSS signals over a measurement cycle. The method may include implementing, by the GNSS receiver, a time-division signal blanking mechanism to identify LOS- only signals received during the measurement cycle.

[0071] In some embodiments, the implementing, by the GNSS receiver, the time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle may include generating, by the GNSS receiver, a plurality of blanking patterns. In someembodiments, the implementing, by the GNSS receiver, the time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle may include obtaining, by the GNSS receiver, a plurality of virtual channels by applying each of the plurality of blanking patterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle. In some embodiments, the implementing, by the GNSS receiver, the timedivision signal blanking mechanism to identify LOS-only signals received during the measurement cycle may include identifying, by the GNSS receiver, a LOS-only virtual channel from the plurality of virtual channels.

[0072] In some embodiments, the implementing, by the GNSS receiver, the time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle may include comparing a distance measurement associated with each of the plurality of virtual channels. In some embodiments, the implementing, by the GNSS receiver, the time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle may include identifying the plurality of virtual channels with a lowest distance measurement as the LOS-only virtual channel.

[0073] In some embodiments, the method may include performing, by the GNSS receiver, position estimation based on the LOS-only virtual channel.

[0074] In some embodiments, the method may include identifying, by the GNSS receiver, that the GNSS receiver is moving through an urban canyon environment. In some embodiments, in response to identifying the GNSS receiver is moving through the urban canyon environment, the method may include activating, by the GNSS receiver, a time-division component to implement the time-division signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

[0075] In some embodiments, the identifying, by the GNSS receiver, that the GNSS receiver is moving through an urban canyon environment comprises determining that a range residual error associated with GNSS signal measurement meets a first threshold value. In some embodiments, the identifying, by the GNSS receiver, that the GNSS receiver is moving through an urban canyon environment comprises determining that the GNSS receiver when a motion sensor measurement meets a second threshold value.

[0076] The foregoing description of the specific embodiments will so reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and / or adapt for various applications such specific embodiments, without undueexperimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0077] Embodiments of the present disclosure have been described above with the aid of functional obstacle blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional obstacle blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0078] The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0079] Various functional blocks, modules, and steps are disclosed above. The particular arrangements provided are illustrative and without limitation. Accordingly, the functional blocks, modules, and steps may be re-ordered or combined in different ways than in the examples provided above. Likewise, certain embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted.

[0080] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A wireless device, comprising: a global navigation satellite system (GNSS) receiver configured to: obtain a plurality of GNSS signals over a measurement cycle; and implement a time-division signal blanking mechanism to identify line-of-sight (LOS)-only signals received during the measurement cycle.

2. The wireless device of claim 1, wherein, to implement the time-division signal blanking mechanism, the GNSS receiver is configured to: generate a plurality of blanking patterns; obtain a plurality of virtual channels by applying each of the plurality of blanking patterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle; and identify a LOS-only virtual channel from the plurality of virtual channels.

3. The wireless device of claim 2, wherein, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver is configured to: compare a distance measurement associated with each of the plurality of virtual channels; and identify the plurality of virtual channels with a lowest distance measurement as the LOS- only virtual channel.

4. The wireless device of claim 3, wherein the GNSS receiver is further configured to: perform position estimation based on the LOS-only virtual channel.

5. The wireless device of claim 1, wherein the GNSS receiver is further configured to: identify that the GNSS receiver is moving through an urban canyon environment.

6. The wireless device of claim 5, wherein, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver is configured to: determine that a range residual error associated with GNSS signal measurement meets a first threshold value; anddetermine that the GNSS receiver when a motion sensor measurement meets a second threshold value.

7. The wireless device of claim 5, wherein the GNSS receiver is configured to: in response to identifying the GNSS receiver is moving through the urban canyon environment, activate a time-division component to implement the time-division signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

8. An apparatus for wireless communication, comprising: a communication interface configured to: receive a plurality of GNSS signals over a measurement cycle; a global navigation satellite system (GNSS) receiver configured to: obtain the plurality of GNSS signals over the measurement cycle; and implement a time-division signal blanking mechanism to identify line-of-sight (LOS)-only signals received during the measurement cycle.

9. The apparatus of claim 8, wherein, to implement the time-division signal blanking mechanism, the GNSS receiver is configured to: generate a plurality of blanking patterns; obtain a plurality of virtual channels by applying each of the plurality of blanking patterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle; and identify a LOS-only virtual channel from the plurality of virtual channels.

10. The apparatus of claim 9, wherein, to identify the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver is configured to: compare a distance measurement associated with each of the plurality of virtual channels; and identify the plurality of virtual channels with a lowest distance measurement as the LOS- only virtual channel.

11. The apparatus of claim 10, wherein the GNSS receiver is further configured to:perform position estimation based on the LOS-only virtual channel.

12. The apparatus of claim 8, wherein the GNSS receiver is further configured to: identify that the GNSS receiver is moving through an urban canyon environment.

13. The apparatus of claim 12, wherein, to identify that the GNSS receiver is moving through an urban canyon environment, the GNSS receiver is configured to: determine that a range residual error associated with GNSS signal measurement meets a first threshold value; and determine that the GNSS receiver when a motion sensor measurement meets a second threshold value.

14. The apparatus of claim 12, wherein the GNSS receiver is configured to: in response to identifying the GNSS receiver is moving through the urban canyon environment, activate a time-division component to implement the time-division signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

15. A method of wireless communication of a user equipment, comprising: obtaining, by a global navigation satellite system (GNSS) receiver, a plurality of GNSS signals over a measurement cycle; and implementing, by the GNSS receiver, a time-division signal blanking mechanism to identify line-of-sight (LOS)-only signals received during the measurement cycle.

16. The method of claim 15, wherein the implementing, by the GNSS receiver, the time-division signal blanking mechanism to identify LOS-only signals received during the measurement cycle comprises: generating, by the GNSS receiver, a plurality of blanking patterns; obtaining, by the GNSS receiver, a plurality of virtual channels by applying each of the plurality of blanking patterns to a subset of the plurality of GNSS signals associated with a segment of the measurement cycle; and identifying, by the GNSS receiver, a LOS-only virtual channel from the plurality of virtual channels.

17. The method of claim 16, wherein the identifying, by the GNSS receiver, the LOS-only virtual channel from the plurality of virtual channels, the GNSS receiver comprises: comparing a distance measurement associated with each of the plurality of virtual channels; and identifying the plurality of virtual channels with a lowest distance measurement as the LOS- only virtual channel.

18. The method of claim 17, further comprising performing, by the GNSS receiver, position estimation based on the LOS-only virtual channel.

19. The method of claim 15, further comprising: identifying, by the GNSS receiver, that the GNSS receiver is moving through an urban canyon environment; and in response to identifying the GNSS receiver is moving through the urban canyon environment, activating, by the GNSS receiver, a time-division component to implement the timedivision signal blanking mechanism to identify the LOS-only signals received during the measurement cycle.

20. The method of claim 19, wherein the identifying, by the GNSS receiver, that the GNSS receiver is moving through an urban canyon environment comprises: determining that a range residual error associated with GNSS signal measurement meets a first threshold value; and determining that the GNSS receiver when a motion sensor measurement meets a second threshold value.

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