Parallel shift estimation for LOS MIMO communication

Abstract

Methods and apparatus for line-of-sight multiple-input multiple-output (LOS MIMO) wireless communication are described. And sending the first pilot signal to the second equipment. The first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of a first device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. patent application No. 17 / 954,198, entitled “PARALLEL SHIFTESTIMATION FOR LOS MIMO COMMUNICATION,” filed by SEN et al. on September 27, 2022, which is assigned to the assignee of this application and is expressly incorporated herein by reference. Background Art Technical Field

[0003] The present disclosure relates, for example, to wireless communication systems, and more particularly to communication systems using line-of-sight (LOS) multiple-input multiple-output (MIMO) technology. Background Art

[0005] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, etc. These systems may be capable of supporting communications with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM).

[0006] By way of example, a wireless multiple access communication system may include multiple base stations, each base station simultaneously supporting communication for multiple communication devices, otherwise referred to as user equipment (UE). The base station may communicate with the UE on a downlink channel (e.g., for transmissions from the base station to the UE) and an uplink channel (e.g., for transmissions from the UE to the base station). Generally speaking, the fixed antenna arrays of the devices cannot easily change their position or orientation, wherein the communication performance of LOS wireless communication strongly depends on possible misalignment of the antenna arrays of the respective communication devices.

[0007] Thus, misalignment of the antenna array may significantly degrade communication performance, depending on the type and amount of misalignment. Summary of the invention

[0008] The described techniques relate to improved methods, systems, devices, and apparatuses that support line-of-sight (LOS) MIMO.

[0009] In some aspects, a transmitting device (hereinafter also referred to as a "first device" (e.g., a base station, an integrated access and backhaul (IAB) node, a relay node, a network node, a gNB, a user equipment (UE), etc.) and a receiving device (hereinafter also referred to as a "second device" (e.g., a UE, a base station, an IAB node, a relay node, a customer premises equipment (CPE), a drone, etc.) may communicate via line-of-sight (LOS) MIMO.

[0010] In some aspects, LOS MIMO communication occurs in a backhaul link between a transmitting device (e.g., a network node) and a receiving device (e.g., a relay), or in an access link between a transmitting device (e.g., a network node or relay) and a receiving device (e.g., a UE).

[0011] A method for wireless communication for line-of-sight multiple-input multiple-output (LOS MIMO) at a first or transmitting device is described. The method includes sending a first pilot signal to a second device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0012] As specified in the present disclosure, it is beneficial to estimate antenna array misalignment to improve LOS MIMO communication performance. In particular, the use of different pilot signals (eg, constant phase pilots or linear phase ramp pilots) provides an improved technique for initiating a misalignment estimation procedure.

[0013] An apparatus for wireless communication for LOS MIMO at a first device is described. The apparatus includes: a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to send a first pilot signal to a second device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating a misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0014] Another apparatus for wireless communication for LOS MIMO at a first device is described. The apparatus includes: means for sending a first pilot signal to a second device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0015] A non-transitory computer-readable medium storing code for wireless communication at a first / transmitting device is described. The code includes instructions executable by a processor to send a first pilot signal to a second device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0016] A method for wireless communication for line-of-sight multiple-input multiple-output (LOS MIMO) at a second or receiving device is described. The method includes: receiving a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot; estimating a misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0017] As specified in the present disclosure, it is beneficial to estimate antenna array misalignment to improve LOS MIMO communication performance. In particular, the use of different pilot signals (eg, constant phase pilots or linear phase ramp pilots) provides an improved technique for initiating a misalignment estimation procedure.

[0018] An apparatus for wireless communication for LOS MIMO at a second device is described. The apparatus includes a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to receive a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating a misalignment of a second antenna array of the first device relative to a first antenna array of the first device.

[0019] Another apparatus for wireless communication for LOS MIMO at a second device is described. The apparatus includes: means for receiving a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot; means for estimating a misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0020] A non-transitory computer-readable medium storing code for wireless communication at a second device is described. The code includes instructions executable by a processor to receive a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0021] The features and technical advantages of the examples according to the present disclosure have been outlined quite extensively above so that the following specific embodiments may be better understood. Additional features and advantages will be described below. The disclosed concepts and specific examples may be easily used as the basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. When considered in conjunction with the accompanying drawings, the characteristics of the concepts disclosed herein (both their organization and methods of operation) and the associated advantages will be better understood according to the following description. Each of the accompanying drawings is for illustration and description purposes only and is not intended to be a limitation of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order that the above-recited features of this disclosure may be understood in detail, a more particular description, briefly summarized above, may be had by reference to certain aspects illustrated in the appended drawings.

[0023] It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0024] Figure 1 An exemplary wireless network according to various aspects of the present disclosure is illustrated.

[0025] Figure 2 An exemplary transmitting device communicating with a receiving device in a wireless network according to various aspects of the present disclosure is illustrated.

[0026] Figure 3 An exemplary antenna array of a transmitting device and an exemplary antenna array of a receiving device according to various aspects of the present disclosure are illustrated.

[0027] Figure 4a Exemplary antenna array misalignments according to various aspects of the present disclosure are illustrated.

[0028] Figure 4b Exemplary antenna array misalignments according to various aspects of the present disclosure are illustrated.

[0029] Figure 4c Exemplary antenna array misalignments according to various aspects of the present disclosure are illustrated.

[0030] Figure 5 An exemplary process flow for estimating antenna array misalignment in accordance with aspects of the present disclosure is illustrated.

[0031] Figure 6a An exemplary antenna array that generates a constant phase pilot is illustrated.

[0032] Figure 6b An exemplary antenna array that generates linear phase ramped pilots is illustrated.

[0033] Figure 7 Exemplary antenna array misalignments according to various aspects of the present disclosure are illustrated.

[0034] Figure 8a An example of detecting phase of a pilot signal for rotation-based shift estimation according to various aspects of the present disclosure is illustrated.

[0035] Figure 8b An example of detecting phase of a pilot signal for rotation-based shift estimation according to various aspects of the present disclosure is illustrated.

[0036] Fig. 9 The inner product of the received phase and the projected phase for direct shift estimation is illustrated.

[0037] Fig.10 An exemplary performance comparison of rotation-based parallel shift estimation and inner-product-based direct shift estimation according to various aspects of the present disclosure is illustrated.

[0038] Fig.11 A flow chart illustrating an exemplary method of supporting transmitting a first pilot signal according to aspects of the present disclosure is illustrated.

[0039] Fig.12 A flow chart illustrating an exemplary method of supporting receiving a first pilot signal in accordance with aspects of the present disclosure is illustrated.

[0040] Fig.13 A block diagram illustrating an exemplary device supporting transmitting a first pilot signal according to aspects of the present disclosure is illustrated.

[0041] Fig.14 A block diagram of an exemplary device supporting receiving a first pilot signal according to aspects of the present disclosure is illustrated.

[0042] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0043] Generally speaking, line-of-sight multiple-input multiple-output (LOS MIMO) can provide high multiplexing gain for certain conditions. High multiplexing gain can be achieved when the distance between the antenna array of the transmitting device (Tx) (the term "transmitting device" is interchangeable and can be replaced by more general terms such as "first device") and the antenna array of the receiving device (Rx) (the term "receiving device" is interchangeable and can be replaced by more general terms such as "second device") does not exceed a certain threshold. This threshold in turn depends on parameters such as the aperture or carrier frequency of the Tx and Rx antenna arrays. Another condition for achieving high multiplexing gain can be the use of an accurate LOS MIMO pre-decoder. The accurate pre-decoder in turn depends on, for example, channel knowledge on the TX side, distance feedback, and possible antenna array misalignment compensation.

[0044] When the Tx and Rx antenna arrays are perfectly aligned (e.g., the antenna arrays face each other and are centered), high performance gain can be achieved. However, depending on the type and amount of misalignment, misalignment of the antenna arrays can significantly degrade performance. In most deployment scenarios for LOS MIMO, the Tx and Rx antenna arrays have fixed positions, or at least remain in a specific position for a longer period of time. Generally speaking, fixed antenna arrays cannot easily change their position or orientation. Therefore, the communication performance of LOS wireless communication strongly depends on possible misalignment of the antenna arrays of the corresponding communication devices (e.g., misalignment of the Tx antenna array, or the Rx antenna array, or both).

[0045] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for LOS MIMO communications associated with antenna array misalignment compensation.

[0046] The following description provides examples, but does not limit the scope, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of the present disclosure. Various examples may omit, replace, or add various procedures or components as appropriate. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described with respect to some examples may be combined in other examples.

[0047] There are multiple deployment scenarios with different requirements with respect to LOS MIMO. For example, LOS MIMO can be deployed at network nodes (e.g., gNB、IAB、 In the backhaul link between the side link (SL) UE, etc.) and the relay (IAB, smart repeater, customer premises equipment (CPE), drone, etc.). In another example, LOS MIMO can be deployed in the access link between the network node / relay and the UE.

[0048] Figure 1An exemplary wireless network 100 according to various aspects of the present disclosure is illustrated. The wireless network 100 may be an element of a 5G (NR) network, an LTE network, a 6G network, etc., or may include elements of a 5G (NR) network, an LTE network, a 6G network, etc. The wireless network 100 may include a plurality of base stations (BSs) 105 (shown as BS105a, BS105b, BS105c, and BS105d) and other network entities. A base station (BS) is an entity that communicates with a user equipment (UE) and may also be referred to as an NR BS, a B node, a gNB, a 5G Node B (NB), an access point, a transmit receive point (TRP), etc. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0049] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown in , BS 105a may be a macro BS for macro cell 102a, BS 105b may be a pico BS for pico cell 102b, and BS 105c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0050] In some aspects, the cell need not be stationary, and the geographic area of ​​the cell may move according to the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (such as direct physical connections, virtual networks, etc.) using any suitable transport network.

[0051] The wireless network 100 may also include a relay station 105d. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and transmit the transmissions of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in , relay BS 105d can communicate with macro BS 105a and UE 115d to facilitate communication between BS 105a and UE 115d. Relay BS may also be referred to as a relay station, relay base station, relay, etc.

[0052] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 watts to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 watt to 2 watts).

[0053] A network controller 130 may be coupled to a group of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via backhaul. The BSs may also communicate with each other (eg, directly or indirectly via wireless or wired backhaul).

[0054] UE 115 (e.g., 115a, 115b, 115c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet device, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biosensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicle-mounted component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless medium or a wired medium.

[0055] Some UEs may be considered as machine type communication (MTC) UEs, or evolved or enhanced machine type communication (eMTC) UEs. For example, MTC and eMTC UEs include robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to or to a network (e.g., a wide area network (such as the Internet) or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 115 may be included in a housing that houses components of UE 115, such as a processor component, a memory component, etc. In some aspects, the processor component and the memory component may be coupled together. For example, a processor component (e.g., one or more processors) and a memory component (e.g., a memory) may be operably coupled, communicatively coupled, electronically coupled, electrically coupled, etc.

[0056] Generally speaking, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific RAT and may operate on one or more frequencies. RAT may also be referred to as radio technology, air interface, etc. Frequency may also be referred to as carrier, frequency channel, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR, 5G RAT networks or future 6G RAT technologies may be deployed.

[0057] In some aspects, two or more UEs 115 (e.g., shown as UE 115a and UE 115e) may communicate directly (e.g., without using base station 105 as an intermediary to communicate with each other) using one or more sidelink channels. For example, UE 115 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, etc.), mesh networks, etc. In this case, UE 115 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein performed by base station 105.

[0058] The devices of the wireless network 100 may communicate using an electromagnetic spectrum, which may be subdivided into various categories, bands, channels, etc. based on frequency or wavelength. For example, the devices of the wireless network 100 may communicate using an operating band having a first frequency range (FR1) that may span from 410 MHz to 7.125 GHz, and / or may communicate using an operating band having a second frequency range (FR2) that may span from 24.25 GHz to 52.6 GHz. Frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a "sub-6 GHz" band. Similarly, FR2 is often referred to as a "millimeter wave" band, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified by the International Telecommunication Union (ITU) as a "millimeter wave" band. Therefore, unless otherwise expressly stated, it should be understood that the term "sub-6 GHz" and the like (if used herein) can broadly refer to frequencies less than 6 GHz, frequencies within FR1, and / or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, unless otherwise expressly stated, it should be understood that the term "millimeter wave" and the like (if used herein) can broadly refer to frequencies within the EHF band, frequencies within FR2, and / or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies included in FR1 and FR2 may be modified, and the techniques described herein may be applicable to those modified frequency ranges.

[0059] In with Figure 1 In a related example, a transmitting (Tx) device 105 (e.g., a base station) or a receiving (Rx) device 105 (e.g., a CPE, a relay, an IAB, a smart repeater, a drone, a UE) may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. For example, the wireless communication system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115), wherein the transmitting device may be equipped with multiple antennas, and the receiving device may be equipped with one or more antennas.

[0060] Conventional MIMO communications may employ multipath signal propagation to increase spectral efficiency by sending or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may be sent, for example, by a transmitting device via different antennas or different combinations of antennas. Similarly, the multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), in which multiple spatial layers are sent to the same receiving device; and multi-user MIMO (MU-MIMO), in which multiple spatial layers are sent to multiple devices. In conventional MIMO systems, signals from transmitting devices propagate through multiple paths due to reflections and environmental influences.

[0061] In the upcoming 3rd Generation Partnership Project (3GPP) releases (e.g., Release 19 and later), line-of-sight (LOS) MIMO technology may become more important. By using line-of-sight propagation, a corresponding signal propagates in a direct path from a first device (e.g., a transmitting device) to a second device (e.g., a receiving device), or vice versa.

[0062] As indicated above, Figure 1 are provided as examples. Other examples can be found in the Figure 1 The examples described are different.

[0063] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or direct an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array so that signals propagating at a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the transmitting device or the receiving device applying a particular amplitude and phase shift to the signal carried via each antenna element associated with the device. The adjustments associated with each of these antenna elements may be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device or relative to some other direction).

[0064] In one example, the base station 105 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE 115. For example, some signals (e.g., control signals) may be sent multiple times by the base station 105 in different directions, which may include a signal being sent according to different beamforming weight sets associated with different transmission directions. The transmissions in different beam directions may be used (e.g., by the base station 105 or a receiving device, such as the UE 115) to identify a beam direction used by the base station 105 for subsequent transmission and / or reception.

[0065] Figure 2 An exemplary wireless communication system supporting communication via LOS MIMO according to various aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 may implement various aspects of the wireless communication system 100. In some examples, the wireless communication system 200 may be an example of a sixth generation (6G) system, a fifth generation (5G) system, or other generation systems. In the exemplary communication system 200, a communication device (e.g., a base station 105a, a relay 105d, a CPE / UE 115a, 115d) may send or receive beams on a communication link 205a, 205b, or 205c. For example, LOS MIMO communication may occur in a backhaul link 205b between a transmitting device (e.g., a network node or base station 105a) and a receiving device (e.g., a relay 105d), or in an access link 205a, 205c between a transmitting device (e.g., a network node, a base station 105a, or a relay 105d) and a receiving device (e.g., a UE 115a, 115d).

[0066] In addition, although shown as being between a base station 105a and a UE 115a, the base station 105a or the UE 115a or both may send or receive signals (e.g., pilot signals) to or from other wireless devices, such as peer devices. For example, the base station 105a may send or receive a pilot signal to or from another base station 105, and the UE 115a may send or receive a pilot signal to or from another UE 115 by implementing the described techniques without exceeding the scope of the present disclosure. Additionally or alternatively, the techniques discussed herein may be used in communications between IAB nodes, relay nodes, access points, other wireless devices, or any combination thereof.

[0067] Aligned antenna array

[0068] The present disclosure relates to line-of-sight (LOS) MIMO for wireless communications, which will become more important in upcoming 3GPP releases. In line-of-sight propagation, a signal propagates in a direct path from a first device (e.g., a transmitting device) to a second device (e.g., a receiving device).

[0069] In some cases, the antenna of the first device (e.g., a base station, a relay, a transmitting device, etc.) or the second device (e.g., a UE, a CPE, a relay, a receiving device, etc.) may include one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming.

[0070] For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with base station 105 may be located at different geographic locations. In some examples, base station 105 may have an antenna array with rows and columns of antenna ports that base station 105 may use to support beamforming for communications with UE 115. Likewise, UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

[0071] In other examples, the antenna array of the first device or the second device may have antennas arranged in a circular manner.

[0072] It is desirable to achieve high performance of LOS MIMO wireless communications. Therefore, it may be advantageous if the antenna arrays of the first device and the second device are aligned with each other. Possible misalignment of the antenna arrays may result in performance losses of LOS MIMO communications.

[0073] Figure 3 An exemplary antenna array 305 of a first device (eg, a transmitting device) is illustrated aligned with an exemplary antenna array 315 of a second device (eg, a receiving device).

[0074] exist Figure 3 In the example, the antenna array 305 of the first device is located in the first xy plane ( Figure 3 : defined by x1 and y1), wherein the antenna array 315 of the second device is located in the second xy plane ( Figure 3 : defined by x2 and y2), the second xy plane is parallel to the first xy plane, wherein the origin of the second plane or the second coordinate system (x2 = 0, y2 = 0, z2 = 0) is located on the z-axis (z1) of the first coordinate system (e.g. Figure 3 Note that the z-axis of the first coordinate system (z1) is parallel to the z-axis of the second coordinate system (z2).

[0075] exist Figure 3In the example, the center of the first antenna array is located at the origin of the first x-y plane / coordinate system, where the center of the second antenna array is located at the origin of the second x-y plane / coordinate system. Additionally, the first antenna array and the second antenna array face each other. Thus, the antenna arrays are aligned.

[0076] Generally speaking, the polarization channel matrix can be described by the following Rician channel model: H = aH LOS + bH NLOS , where H LOS represents the line-of-sight component, and

[0077] H NLOS represents the non-line-of-sight component (with rich randomness). In particular, the elements of H LOS depend on where r jk corresponds to the distance from the k-th transmitter antenna to the j-th receiver antenna; H NLOS ∈{i.i.d. Rayleigh, CDL-x, TDL-x} and a 2 + b 2 = 1, where LOS percentage = a 2 .

[0078] For LOS MIMO, the exemplary antenna array can be designed as 1D or 2D circular. Referring to the Rician channel model, the LOS component is strong for LOS MIMO (a >> b), and the SVD-based precoder is implicit and benefits from the special structure of the channel (finite / no CSF).

[0079] In contrast, for massive MIMO (mMIMO), the channel matrix has a weak LOS component (a < b) and the SVD-based precoder is explicit, where CSF is required at the Tx side to calculate the SVD.

[0080] Misalignment of the antenna array

[0081] To achieve high communication performance for LOS MIMO, it is beneficial to align the antenna arrays of the communication devices (e.g., the antenna arrays of the first device and the second device). Otherwise, misalignment of the antenna arrays can lead to performance loss in LOS MIMO communication.

[0082] As has been illustrated with respect to Figure 3 , when the first antenna array and the second antenna array are located in parallel x-y planes, a perfectly aligned situation can be achieved, where the centers of the corresponding first antenna array and the second antenna array coincide with the origin of the corresponding coordinate system (i.e., the antenna arrays should face each other).

[0083] However, antenna array misalignment may significantly degrade communication performance, depending on the type and amount of misalignment. Figure 4a , Figure 4b and Figure 4c An example of misalignment of different types of antenna arrays (305, 315) of a first (eg, Tx) or second (eg, Rx) device is illustrated. Figure 4a and Figure 4b Examples are provided in which the center of the first antenna array 305 or the second antenna array 315 is shifted in the xy plane by a so-called parallel shift.

[0084] In particular, Figure 4a The arrows in indicate possible antenna array shifts in the x-direction or the y-direction.

[0085] Figure 4b An exemplary second antenna array 315 is illustrated that is parallel displaced (Δ) in the x-direction. Figure 4b , the center of the second antenna array 315 does not coincide with the origin of the second coordinate system. Therefore, the first antenna array 305 and the second antenna array 315 are not aligned. Parallel displacement (no rotational misalignment) corresponds to an exemplary misalignment in which the antenna arrays cannot directly face each other.

[0086] exist Figure 4c In the example of FIG, rotational misalignment of an exemplary antenna array is shown. In particular, rotational misalignment may occur when the antenna array is rotated relative to the z-axis (parallel rotation) or relative to the x-axis or y-axis (vertical rotation).

[0087] The present disclosure relates to parallel shift misalignment, and in particular to parallel shift misalignment estimation. However, in some examples, additional rotational misalignment may occur. Generally speaking, suitable estimation of antenna array misalignment (e.g., parallel shift) allows compensation for misalignment of a transmitting device or a receiving device. Various techniques described herein focus on estimating and compensating for parallel shift misalignment. In addition, for misalignment estimation, a new pilot design is introduced.

[0088] Figure 5 An exemplary process flow 500 that supports estimating antenna array misalignment in accordance with aspects of the present disclosure is illustrated. Note that dashed lines represent optional process flow steps.

[0089] exist Figure 5 In some examples, the parallel shift can be estimated by converting the parallel shift into an xy rotation (e.g., with respect to FIG. 6 and Figure 7 exemplified).

[0090] In other examples, the parallel shift (eg, relative to Fig. 9 exemplified).

[0091] In some examples, process flow 500 can implement wireless communication system 100 or 200 (with respect to Figure 1 or Figure 2 300). The process flow 500 may illustrate LOS MIMO-based communication between a first device 501 having a first antenna array 305 and a second device 502 having a second antenna array 315. The first device and the second device may be examples of other devices described herein, such as a transmitting device, a relay, a base station 105, and a receiving device, a UE or CPE 115, etc. Note that the receiving device may also be configured to send or feed back a signal to the transmitting device, wherein the transmitting device may also be configured to receive the signal sent by the receiving device. Alternative examples of process flows may be implemented in which some features are performed in an order different from that described or not performed at all. In some examples, each operation may include additional features not mentioned below, or further operations may be added.

[0092] At 511, a first device 501 having a first antenna array 305 may send a first pilot signal 503 to a second device 502 having a second antenna array 315. In particular, the first pilot signal 503 is at least one of a constant phase pilot or a linear phase ramp pilot for estimating 532 a misalignment of the second antenna array 315 of the second device 502 relative to the first antenna array 305 of the first device 501.

[0093] In one example, the second device 502 may receive a first pilot signal 503 from the first device 305, wherein the first pilot signal 503 may be at least one of a constant phase pilot or a linear phase ramp pilot for estimating a misalignment 532 of the second antenna array 315 of the second device 501 relative to the first antenna array 305 of the first device 502.

[0094] In some examples, estimating misalignment 532 may include estimating a parallel shift of second antenna array 315 relative to first antenna array 305 .

[0095] At 532, the misalignment of the second antenna array 315 may be estimated by estimating the parallel shift of the second antenna array 315 relative to the first antenna array 305. For parallel shift estimation, different estimation methods may be used. For example, the misalignment may be estimated by using a rotation-based estimation (relative to Figure 7 and Figure 8a and Figure 8b Explain in more detail the rotation-based estimation) or direct shift estimation (relative to Fig. 9 Direct shift estimation) is explained in more detail to estimate parallel shift.

[0096] In some examples, the first pilot signal 503 may be a constant phase pilot. Figure 7a illustrates an exemplary antenna array demonstrating a constant phase pilot. Figure 7 As illustrated, a constant phase pilot may be generated at each antenna of the second antenna array by using the same reference signal (RS). For example, the constant phase pilot may be used to indicate a rotation-based parallel shift estimation.

[0097] In other examples, the first pilot signal 503 may be a linear phase ramp pilot. Figure 7 b illustrates an exemplary antenna array demonstrating a linear phase ramp pilot, where the signal of each antenna of the antenna array is rotated by a corresponding phase (e jθ 、e j2θ 、e j3θ 、e j4θ 、e jβ 、e j2β 、e j3β 、e j4β ) modulation. For example, a linear phase ramp pilot may be used to indicate a direct shift estimate.

[0098] In optional step 521 , the first device 501 may receive a first feedback message 504 from the second device 502 based on the estimated misalignment of the second antenna array 315 relative to the first antenna array 305 .

[0099] At 512 , the second device 502 may send a second pilot signal 505 to the first device 502 for estimating a misalignment of the first antenna array 305 of the first device 501 relative to the second antenna array 315 of the second device 501 .

[0100] In addition, at 512, the first device 501 may receive a second pilot signal 505 from the second device 502, wherein the second pilot signal 505 may be at least one of a constant phase pilot or a linear phase ramp pilot. The first device 501 may then estimate a misalignment 531 of the first antenna array 305 of the first device 501 relative to the second antenna array 315 of the second device 502.

[0101] In some examples, estimating misalignment 531 may include estimating a parallel shift of first antenna array 305 relative to second antenna array 315 .

[0102] At 531, the misalignment of the first antenna array 305 may be estimated by estimating the parallel shift of the first antenna array 305 relative to the second antenna array 315. For parallel shift estimation, different estimation methods may be used. For example, the misalignment may be estimated by using a rotation-based estimation (relative to Figure 7 and Figure 8a and Figure 8b Explain in more detail the rotation-based estimation) or direct shift estimation (relative to Fig. 9Direct shift estimation) is explained in more detail to estimate parallel shift.

[0103] In some examples, the second pilot signal 505 may be a constant phase pilot. For example, a constant phase pilot may be generated at each antenna of the second antenna array by using the same reference signal (RS). For example, the constant phase pilot may be used to indicate a rotation-based parallel shift estimate.

[0104] In other examples, the second pilot signal 505 may be a linear phase ramp pilot. For example, a linear phase ramp pilot may be used to indicate a direct shift estimate.

[0105] At optional step 522, the first device 501 may send a second feedback message 506 to the second device 502 based on the estimated misalignment 531 of the first antenna array 305 relative to the second antenna array 315. Additionally, the second device 502 may receive a second feedback message 506 from the first device 501 based on the estimated misalignment of the first antenna array 305 relative to the second antenna array 315 (at 531).

[0106] At 541 , the first device 501 may compensate for the estimated misalignment at the first antenna array 305 .

[0107] In some examples, compensation may include beam steering based on applying the estimated parallel shift to a precoder matrix.

[0108] In other examples (not shown), the estimated misalignment may be resolved by physically aligning the antenna arrays of the first device and the second device.

[0109] At 542 , the second device 502 may compensate for the estimated misalignment at the second antenna array 315 .

[0110] In some examples, compensation may include implicit compensation with an MMSE receiver.For example, instead of applying a post-processor matrix, the receiver may apply MMSE filtering to estimate the transmitted data symbols.

[0111] In other examples, compensation may include beam steering based on applying the estimated parallel shift to a post-processing matrix.

[0112] In other examples (not shown), the estimated misalignment may be resolved by physically aligning the antenna arrays of the first device and the second device.

[0113] In optional step 551, the first device and the second device perform a distance estimation procedure before submitting the first pilot signal 503. Thus, the first device 501 may send an indication 507 to the second device 502 to estimate the distance relative to the first antenna array 305 of the first device 501 and the second antenna array 315 of the second device 502. The first device then receives feedback 509 from the second device based on the estimated distance.

[0114] As an alternative or in addition to the distance estimation procedure, at 561 , the first device 501 can transmit another indication 510 (eg, an indication message or a second indication) to the second device.

[0115] In one example, the indication 510 may include an indication for estimating a misalignment (eg, a parallel shift) by estimating at least one of an X rotation or a Y rotation of the second device, where the indication may be based on the constant phase first pilot signal 503 .

[0116] In another example, the indication 510 may include an indication for estimating the misalignment by direct estimation, where the indication may be based on the linear phase ramp first pilot signal 503 .

[0117] In some examples, the indication 510 for estimating the misalignment may be based on an estimated distance (eg, of a distance estimation procedure at 551 ) relative to the first antenna array 305 of the first device 501 and the second antenna array 315 of the second device 315 .

[0118] In some examples, the first device 501 may send an indication 510 of the first pilot signal (eg, indicating a constant phase pilot or a linear phase ramp pilot) via radio resource control (RRC) signaling before sending the first pilot signal.

[0119] In some examples, indication 510 may include an indication for using a constant phase pilot signal 503 when the estimated distance (obtained at step 551) may be below a particular threshold, or an indication for using a linear phase ramp pilot signal when the estimated distance (obtained at step 551) is above a particular threshold.

[0120] Rotation-based estimation

[0121] The present disclosure relates to estimating misalignment (including parallel shift) of a first antenna array of a first device relative to a second antenna array of a second device or vice versa. One way to estimate parallel shift misalignment of antenna arrays is to apply rotation-based estimation.

[0122] Figure 7This represents an exemplary method for rotation-based parallel shift estimation and is not intended to limit the scope of the present invention.

[0123] Figure 7 A first antenna array 305 and a second antenna array 315 are illustrated, wherein the second antenna array 315 is shifted by a parallel shift Δ (along the y-axis) relative to the first antenna array 305. The first antenna array 305 may be an antenna array of a first device 501 (e.g., a transmitting device), and the second antenna array 315 may be an antenna array of a second device 502 (e.g., a receiving device). Note that the receiving device may also be configured to send or feed back a signal to a transmitting device, wherein the transmitting device may also be configured to receive the signal sent by the receiving device. In particular, the first or so-called transmitting device may be, for example, a base station, a gNB, an IAB, a relay, or a UE, etc. In addition, the second or so-called receiving device may be an IAB, a smart repeater, a CPE, a drone, or a UE, etc.

[0124] like Figure 7 As indicated in , the antenna array 305 of the first device may be located in a first xy plane (defined by x1 and y1) of a first coordinate system (e.g., x1, y1, and z1), wherein the antenna array 315 of the second device may be located in a second xy plane (defined by x2 and y2) of a second coordinate system (e.g., x1, y2, and z2), the second xy plane may be parallel to the first xy plane, wherein the origin of the second coordinate system (or the origin of the second xy plane) may be located on the z-axis of the first coordinate system.

[0125] exist Figure 7 In the example, an x-axis of the first xy plane is parallel to an x-axis of the second xy plane, and a y-axis of the first xy plane is parallel to the y-axis of the second xy plane.

[0126] In some examples (not shown), the parallel displacement of the first antenna array may be in a first xy plane.

[0127] In some examples (e.g., in Figure 7 ), the parallel displacement of the second antenna array may be in a second xy plane. Figure 7 A specific (and non-limiting) example is shown in which the second antenna array is displaced along the y2 axis in a second xy plane (defined by x2 and y2).

[0128] exist Figure 7 In the example of FIG. 1 , the xy planes of the first antenna array and the second antenna array (305 and 315) are separated by a distance d, wherein the second antenna array 315 is parallel shifted by a parallel shift Δ along the y2 axis in the second xy plane. Figure 7), it is assumed that the actual orientation 701 of the first antenna array and the actual orientation 703 of the second antenna array correspond to the (assumed) rotated antenna array orientations 702 and 704. Figure 7 In FIG. 1 , the actual position is shown as a solid line and the (assumed) rotated position is shown as a dashed line. By assuming that the antenna arrays are rotated by θ, the actual distance between the center of the first antenna array and the center of the second antenna array can be calculated by the following formula: d′=d / cos(θ). θ can be calculated by θ=arctan(Δ / d).

[0129] Exemplary embodiments of the present disclosure with respect to rotation-based parallel shift estimation are provided below.

[0130] In some examples, a first pilot signal ( Figure 5 , 503) to estimate the rotation θ of the antenna array on the other side (eg, the rotation of the second antenna array of the second device).

[0131] In some examples, a second pilot signal ( Figure 5 , 505) to estimate the rotation θ of the antenna array on the other side (eg, the rotation of the first antenna array of the first device).

[0132] In some examples, the first device may send a first pilot signal to the second device, where the first pilot signal may be at least one of a constant phase pilot or a linear phase ramp pilot for estimating a misalignment of a second antenna array 315 of the second device (at the second device) relative to a first antenna array 305 of the first device.

[0133] In some examples, the second device may receive a first pilot signal from the first device, where the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot.

[0134] In some examples, the first pilot signal may be a constant phase pilot. For example, the constant phase pilot may be generated at each antenna of the first antenna array by using the same reference signal (RS).

[0135] In some examples, a constant phase pilot may be used to indicate a rotation-based parallel shift estimate.

[0136] In some examples, the second device may estimate a misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

[0137] In some examples, estimating the misalignment may include estimating a parallel shift of the second antenna array relative to the first antenna array.

[0138] In some examples, estimating the parallel shift Δ may include estimating the parallel shift along the x-axis of the second xy plane by estimating a rotation 704 (X rotation) of the second antenna array 315 relative to the x-axis of the second xy plane (eg, θ≠0).

[0139] Additionally or alternatively, in some examples, estimating the parallel shift Δ may include estimating the parallel shift along the y-axis of the second xy plane by estimating a rotation of the second antenna array relative to the y-axis of the second xy plane (Y rotation) (e.g., θ≠0), where the estimate may be based on the received first pilot signal.

[0140] In some examples, the second device may send feedback to the first device based on the estimated misalignment of the second antenna array relative to the first antenna array.

[0141] In some examples, the second device may compensate for the estimated misalignment at the second device.

[0142] In some examples, the first device may receive feedback from the second device based on an estimated misalignment of the second antenna array relative to the first antenna array.

[0143] In some optional examples, the first device may receive a second pilot signal from the second device, wherein the second pilot signal may be at least one of a constant phase pilot or a linear phase ramp pilot. In some examples, the first device may estimate a misalignment of the first antenna array 305 of the first device relative to the second antenna array 315 of the second device, wherein estimating the misalignment may include estimating a parallel shift Δ of the first antenna array 305 relative to the second antenna array 315. In some examples, the second pilot signal may be a constant phase pilot.

[0144] In some examples, estimating the parallel shift Δ may include estimating at least one of estimating the parallel shift along the x-axis of the first xy plane by estimating the rotation of the first antenna array relative to the x-axis of the first xy plane (X rotation) or estimating the parallel shift along the y-axis of the first xy plane by estimating the rotation of the first antenna array relative to the y-axis of the first xy plane (Y rotation).

[0145] In some examples, the first device may compensate for the estimated misalignment at the first antenna array.

[0146] In some examples (e.g., as compared to Figure 8a and Figure 8b The estimation (illustrated) can generally be based on the received pilot signal.

[0147] Figure 8aAn example of a reception phase diagram based on a constant phase pilot signal when a first antenna array of a first device is aligned with a second antenna array of a second device (eg, parallel shift Δ=0 and estimated X rotation or Y rotation θ=0) is illustrated.

[0148] In some examples, a constant phase pilot may be generated at each antenna of the second antenna array by using the same reference signal (RS).

[0149] In one example, the phase of the received pilot signal may be detected by the second antenna array of the second device or the first antenna array of the first device.

[0150] Figure 8b An example of a reception phase diagram based on a constant phase pilot signal when a first antenna array of a first device and a second antenna array of a second device are not aligned (e.g., parallel shift Δ≠0, and assumed X and / or Y rotation θ≠0) is illustrated. Figure 8b In the non-limiting example of , there is rotation in both the x-axis and the y-axis.

[0151] In a general example, estimating a rotation of an antenna array (eg, an X rotation, a Y rotation, or at least one of both) may be based on determining a phase of a pilot signal on a respective antenna of the antenna array.

[0152] In some examples, estimating a rotation of the antenna array (e.g., an X rotation, a Y rotation, or at least one of the two) may be based on determining at least one phase difference (or alternatively, a phase rotation) between two adjacent antennas of the antenna array.

[0153] In some examples, estimating the parallel shift of an antenna array using a rotation-based estimation method may include determining a linear phase slope based on averaging multiple estimates of the phase difference between corresponding two adjacent antennas of the antenna array along an x-axis of the xy plane or (in addition or alternatively) based on averaging multiple estimates of the phase difference between corresponding two adjacent antennas of the antenna array along the y-axis of the xy plane.

[0154] For the purpose of illustration of linear phase ramp determination, it may be assumed that: ij is the received signal at a single receive antenna element at row i and column j of the receiver antenna array. Then, for the rotation-based method, the phase slope across the x-axis (across columns) is calculated by taking the average of adjacent phase differences as follows:

[0155] i.

[0156] where angle_diff(y ij ,y i,j+1 ) indicates the output and input y ij andi,j+1 is a function of the angle difference between them.

[0157] As compared to Figure 8b As illustrated, estimating a rotation of the antenna array (eg, an X rotation, a Y rotation, or at least one of the two) may be based on determining a linear phase ramp.

[0158] In some examples, determining the linear phase ramp includes determining a slope of the phase ramp 801, Figure 8b shown.

[0159] In some examples, estimating the parallel shift may be based on determining a linear phase slope.

[0160] In some examples, estimating the parallel shift may include converting an estimated rotation of the antenna array into the parallel shift.

[0161] In some examples, the rotation-based parallel shift estimation may be initiated by the first device or the second device.

[0162] In some examples, sending or receiving a constant phase pilot signal may initiate rotation-based parallel shift estimation, where the constant phase of the pilot signal may serve as an indication of the rotation-based parallel shift estimation.

[0163] In some examples, the indication for estimating the misalignment can be based on an estimated distance (e.g., of a distance estimation procedure; e.g., relative to a first antenna array of the first device and a second antenna array of the second device). For the distance estimation procedure, reference is made relative to Figure 5 .

[0164] In relation to Figure 5 In some examples, indication 510 may include an indication for estimating misalignment via rotation-based parallel shift estimation, where the indication may be based on a constant phase first pilot signal.

[0165] In some examples, the indication may include an indication for using a constant phase (or a constant phase pilot signal) for the pilot signal when the estimated distance may be below a particular threshold, or an indication for using a linear phase ramp (or a linear phase ramp pilot signal) for the pilot signal when the estimated distance is above a particular threshold.

[0166] For example, an indication to use a linear phase ramped pilot signal may result in misalignment estimation by a direct shift estimation method.

[0167] Direct estimation

[0168] The present invention relates to estimating antenna array misalignments, including parallel shifts, e.g., misalignment of a first antenna array of a first device relative to a second antenna array of a second device, or misalignment of the second antenna array of a second device relative to the first antenna array of the first device. One way to estimate misalignments (e.g., parallel shifts of two antenna arrays) is to apply a direct estimation procedure.

[0169] In one example, estimating the parallel shift may include direct estimation of the parallel shift, where the direct estimation may be based on determining an inner product between pilot signals received at antennas of the second antenna array and pilot signals projected based on one or more hypotheses of the antenna array shift.

[0170] Fig. 9 The inner product of the received phase and the projected phase based on one or more hypotheses of antenna array shift is illustrated.

[0171] Fig. 9 The peaks shown indicate integer / fractional shifts (eg, fractional parallel shift = (1 / 2, 1 / 2); peak is found at = (1 / 2, 1 / 2)).

[0172] Generally speaking, there are various estimation algorithms known in the prior art, such as inner product-based algorithms and phase jump-based algorithms. However, for these two estimation algorithms, the estimation range is limited within the antenna panel. Therefore, the direct estimation algorithm can be applied to the estimation of small parallel shifts.

[0173] In some examples, a first pilot signal (eg, Figure 5 As shown) can be a linear phase ramp pilot.

[0174] In some examples, a second pilot signal (e.g., Figure 5 As shown) can be a linear phase ramp pilot.

[0175] In some examples, a linear phase ramp pilot may be used to indicate a direct shift estimate.

[0176] For example, a linear phase ramp pilot may be generated by using a linear phase ramp at an antenna of a first antenna array (eg, Figure 6b for example).

[0177] The use of a linear phase ramp pilot signal is beneficial. For example, the pilot signal provides a low autocorrelation characteristic with parallel shift.

[0178] In some examples, direct parallel shift estimation may be initiated by the first device or the second device.

[0179] In some examples, sending or receiving a linear phase ramp pilot signal may initiate direct parallel shift estimation.

[0180] In some examples, the indication for estimating the misalignment can be based on a distance estimated by (e.g., of a distance estimation procedure; e.g., relative to a first antenna array of the first device and a second antenna array of the second device). For the exemplary distance estimation procedure, reference is made to the distance estimated relative to Figure 5 .

[0181] In relation to Figure 5 In some examples, indication 510 may include an indication for estimating the misalignment by direct estimation, where the indication may be based on a linear phase ramp first pilot signal.

[0182] In some examples, the indication (e.g., Figure 5 The indication 510 in may include an indication for using a constant phase pilot signal when the estimated distance may be below a certain threshold, or an indication for using a linear phase ramp pilot signal when the estimated distance is above a certain threshold.

[0183] For example, an indication to use a constant phase first pilot signal may result in misalignment estimation by a rotation based estimation method.

[0184] Rotation-based estimation versus direct estimation

[0185] Generally speaking, LOS MIMO may require distance estimation. In such cases, a distance estimation procedure estimates the distance between a first antenna array of a first device and a second antenna array of a second device. In particular, the distance estimation procedure may occur before a misalignment estimation procedure between the first device and the second device. Therefore, depending on the estimated distance, a rotation-based estimation or a direct shift estimation may be initiated.

[0186] Fig.10 An example of performance comparison between an exemplary rotation-based estimation 1001 and an inner-product-based direct shift estimation 1002 is illustrated. Fig.10 The mean square error (MSE) of a parallel shift with respect to a parameter r / λ, which depends on a distance r between respective antenna arrays (eg, a first antenna array and a second antenna array), is illustrated. Figure 5 Examples involve small parallel shifts (e.g., Δ x =Δ y＝ 5λ). In particular, at small distances (e.g., r / λ<~2×10 3 ), the direct shift estimation (based on the inner product) provides a better estimate, where at large distances (e.g., r / λ>~2×10 3), the rotation-based estimation provides a better estimate. However, it should be noted that the rotation-based compensation performance is poor for small distances (r / λ < ∼ 2×10 3 ) is still good. Note that for LOS MIMO communication, the distance is usually limited (e.g., r / λ < ~10 4 ).

[0187] Additionally, using a rotation based shift estimate is beneficial because the rotation based estimate also works for large shifts (since, in this instance, the phase shift is important rather than the actual parallel shift estimate).

[0188] In some examples, the first device may use the first set of pilots to start rotation-based estimation and compensation. If further tuning is needed and the distance between the first antenna array and the second antenna array is small (to achieve better resolution of the shift estimation), the first device may use the second set of pilots to schedule additional estimation procedures (e.g., direct shift estimation) and may apply compensation again.

[0189] like Fig.10 As illustrated, it may be beneficial to use a distance estimation procedure to identify the best performing shift estimation method (eg, rotation-based estimation or direct shift estimation).

[0190] In some examples, a first device having a first antenna array indicates to a second device having a second antenna array which estimation method to use.

[0191] In some examples, the indication depends on the distance between the misaligned antenna arrays (e.g., Figure 5 Steps 551 and 561).

[0192] Parallel shift compensation

[0193] The following provides non-limiting examples of the present invention and relates to compensating for estimated misalignment, specifically compensating for parallel shifts between antenna arrays of different devices. In some examples, the misalignment estimation may be based on: a rotation-based estimation or a direct shift estimation.

[0194] In the case of a perfectly aligned antenna array, the first (or transmitting) device 501 may use a pre-decoder matrix V, where the second (or receiving) device 502 may use a post-processor matrix U for communication.

[0195] To illustrate parallel shift compensation, refer to Figure 4b An exemplary antenna array is not aligned.

[0196] In particular, an estimate of antenna array misalignment (e.g., parallel shift in the xy plane) can provide information about the 3D parallel shift vector knowledge, as illustrated with respect to 4b.

[0197] In addition, the distance estimation procedure (relative to Figure 5 exemplarily illustrated) may provide knowledge about the distance d between a first antenna array of a first (transmitting) device and a second antenna array of a second (receiving) device.

[0198] Based on the distance and misalignment estimates, the predecoder matrix V can be updated at the transmitting side to a new predecoder matrix V new :

[0199]

[0200] in The local coordinates of the jth antenna of the first antenna array corresponding to the first (transmitting) device.

[0201] Based on the distance and misalignment estimates, the post-processing matrix can be updated at the receiving side as a new post-processing matrix U new :

[0202]

[0203] in The local coordinates of the i-th antenna of the second antenna array corresponding to the second (receiving) device.

[0204] For illustration purposes, refer to Figure 4b , showing d. and

[0205] In some examples, beam steering can be utilized at the transmitter side and the receiver side (eg, at the first device and the second device), respectively, to compensate for the parallel shift.

[0206] In other examples, receiver-side compensation may be done implicitly with an MMSE receiver.

[0207] For example, instead of applying a post-processor matrix, the receiver may apply MMSE filtering to estimate the transmitted data symbols.

[0208] Fig.11 A diagram illustrating an example process 1100 performed by an example transmitter (or first device) according to various aspects of the present disclosure is shown. Process 1100 provides an example in which a transmitter (eg, first device 501) performs operations associated with LOS MIMO-based communications.

[0209] like Fig.11 As shown (block 1101), in some aspects, process 1100 may include sending (e.g., using Fig.13 The transmitting component 1304 depicted in the figure) sends a first pilot signal, wherein the first pilot signal can be a constant phase pilot signal or a linear phase ramp pilot signal for estimating the misalignment of the second antenna array of the second device relative to the first antenna array of the first device.

[0210] like Fig.11 As further shown in (block 1102), in some aspects, process 1100 may include receiving from a second device (e.g., using Fig.13 Receive component 1302) feedback as depicted.

[0211] like Fig.11 As further shown in (block 1103), in some optional aspects, process 1100 may include receiving from a second device (e.g., using Fig.13 The receiving component 1302 depicted in FIG. 1 ) receives a second pilot signal, wherein the second pilot signal can be a constant phase pilot signal or a linear phase ramp pilot signal.

[0212] like Fig.11 As further shown in (block 1104), in some optional aspects, process 1100 can include estimating a misalignment of a first antenna array of the first device relative to a second antenna array of the second device.

[0213] like Fig.11 As further shown in (block 1105), in some optional aspects, process 1100 may include compensating for the estimated misalignment. In particular, the compensation may include compensating for the estimated misalignment of the first antenna array or compensating for at least one of the estimated misalignment of the second antenna array.

[0214] Process 1100 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0215] In the first aspect, the first pilot signal may be a constant phase pilot signal.

[0216] In a second aspect, a constant phase pilot signal may be generated at each antenna of a first antenna array by using the same reference signal (RS).

[0217] In a third aspect, the second pilot signal may be a constant phase pilot signal.

[0218] In some aspects, a constant phase pilot signal may be used to indicate a rotation-based parallel shifting procedure.

[0219] In some aspects, estimating the misalignment may include estimating a parallel shift of the first antenna array relative to the second antenna array.

[0220] In a fourth aspect, an antenna array of a first device may be located in a first xy plane of a first coordinate system, wherein an antenna array of a second device may be located in a second xy plane of a second coordinate system, the second xy plane being parallel to the first xy plane, wherein an origin of the second coordinate system may be located on a z-axis of the first coordinate system, wherein a parallel shift of the first antenna array may be in the first xy plane, wherein at least one of the first pilot signal or the second pilot signal may be a constant phase pilot, wherein estimating the parallel shift may include estimating at least one of a parallel shift along an x-axis of the first xy plane by estimating a rotation of the first antenna array relative to an x-axis of the first xy plane (X rotation) or estimating a parallel shift along a y-axis of the first xy plane by estimating a rotation of the first antenna array relative to a y-axis of the first xy plane (Y rotation), wherein the estimation may be based on a received second pilot signal. In some aspects, estimating the parallel shift includes converting the estimated X-rotation or Y-rotation of the first antenna array into a parallel shift.

[0221] In a fifth aspect, estimating at least one of an X-rotation and a Y-rotation of the first antenna array may be based on determining a phase of a received second pilot signal on an antenna of the first antenna array.

[0222] In a sixth aspect, estimating at least one of an X-rotation and a Y-rotation of the first antenna array may be based on determining a phase of a received second pilot signal on an antenna of the first antenna array.

[0223] In a seventh aspect, estimating at least one of an X-rotation and a Y-rotation of the first antenna array may be based on determining at least one phase difference between two adjacent antennas in the first antenna array.

[0224] In an eighth aspect, process 1100 may include determining a linear phase ramp based on at least one of: averaging multiple estimates of the phase difference between corresponding two adjacent antennas in the first antenna array along an x-axis of a first xy plane, or averaging multiple estimates of the phase difference between corresponding two adjacent antennas in the first antenna array along a y-axis of the first xy plane.

[0225] In a ninth aspect, an x-axis of the first xy plane and an x-axis of the second xy plane may be parallel, and / or a y-axis of the first xy plane and a y-axis of the second xy plane may be parallel.

[0226] In a tenth aspect, estimating at least one of an X-rotation and a Y-rotation of the first antenna array may be based on determining a linear phase ramp.

[0227] In an eleventh aspect, estimating the parallel shift may be based on determining a linear phase ramp, wherein in some examples, estimating the parallel shift may include converting at least one of the estimated X and Y rotations of the first antenna array into a parallel shift.

[0228] In a twelfth aspect, estimating the parallel shift may include direct estimation of the parallel shift, wherein the direct estimation may be based on determining an inner product between pilot signals received at antennas of the first antenna array and pilot signals projected based on one or more hypotheses of the antenna array shift.

[0229] In the thirteenth aspect, the first pilot signal may be a linear phase ramp pilot signal.

[0230] In the fourteenth aspect, the second pilot signal may be a linear phase ramp pilot signal.

[0231] In some aspects, a linear phase ramp pilot signal may be used to indicate a direct shift estimation procedure.

[0232] In a fifteenth aspect, compensating can include beam steering based on applying the estimated parallel shift to a precoder matrix.

[0233] In a sixteenth aspect, process 1100 may comprise sending to a second device a (eg, first) indication estimating a distance relative to a first antenna array of the first device and a second antenna array of the second device; and receiving feedback from the second device based on the estimated distance.

[0234] In a seventeenth aspect, process 1100 may include sending a (e.g., second) indication to a second device for estimating misalignment (specifically, parallel shift) by estimating at least one of an X rotation and a Y rotation of the second device, wherein the indication may be based on a constant phase first pilot signal.

[0235] In an eighteenth aspect, process 1100 can include sending a (eg, second) indication to a second device for estimating a misalignment (specifically, a parallel shift) by direct estimation, where the indication can be based on a linear phase ramp first pilot signal.

[0236] In a nineteenth aspect, the indication for estimating misalignment is based on an estimated distance relative to a first antenna array of the first device and a second antenna array of the second device.

[0237] In a twentieth aspect, process 1100 can include sending a (eg, second) indication of a first pilot signal (indicating a constant phase pilot or a linear phase ramp pilot) via radio resource control (RRC) signaling prior to sending the first pilot signal.

[0238] In further aspects, process 1100 may include sending a second indication for estimating parallel shift by estimating at least one of X and Y rotations when the estimated distance is below a particular threshold, or sending a second indication for estimating parallel shift by direct estimation when the estimated distance is above a particular threshold.

[0239] The sending of the second indication depending on the estimated distance may be advantageous.In particular, the estimated distance may be used to select a suitable estimation procedure (eg rotation-based estimation or direct estimation) providing the highest communication performance.

[0240] although Fig.11 An example block diagram of process 1100 is shown, but in some aspects, process 1100 may include Fig.11 Additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in the process 1100. Additionally or alternatively, two or more blocks of the blocks of process 1100 may be performed in parallel.

[0241] Fig.12 is a diagram illustrating an example process 1200 performed, for example, by a receiver (or a second device) according to various aspects of the present disclosure. The example process 1200 is an example in which a receiver (eg, the second device 502) performs operations associated with LOS MIMO-based communications.

[0242] like Fig.12 As shown (block 1201), in some aspects, process 1200 may include receiving (e.g., using) from a first device Fig.14 The receiving component 1402 depicted in FIG. 1 ) receives a first pilot signal, wherein the first pilot signal can be a constant phase pilot signal or a linear phase ramp pilot signal.

[0243] like Fig.12 As further shown in (block 1202), in some aspects, process 1200 may include estimating a misalignment of a second antenna array of a second device relative to a first antenna array of a first device.

[0244] like Fig.12 As further shown in (block 1203), in some aspects, process 1200 may include sending (e.g., using) to the first device based on the estimated misalignment of the second antenna array relative to the first antenna array. Fig.14 The sending component 1404) feedback depicted in FIG.

[0245] like Fig.12 As further shown in (block 1204), in some optional aspects, process 1200 can include compensating for the estimated misalignment of the second device.

[0246] like Fig.12As further shown in (block 1205), in some optional aspects, process 1200 may include sending to the first device (e.g., using Fig.14 The transmitting component 1404 depicted in FIG. 1 is used to estimate a second pilot signal of a misalignment of a first antenna array of a first device relative to a second antenna array of a second device.

[0247] Process 1200 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0248] In the first aspect, the first pilot signal may be a constant phase pilot signal, or wherein the second pilot signal may be a constant phase pilot signal.

[0249] The constant phase pilot signal may be used to indicate the rotation-based parallel shift estimation procedure.

[0250] In a second aspect, the same reference signal (RS) may be used to transmit the same signal to a second antenna array (eg, Figure 6a A constant phase pilot signal is generated at each antenna (example).

[0251] In some aspects, estimating the misalignment may include estimating a parallel shift of the second antenna array relative to the first antenna array.

[0252] In a third aspect, the antenna array of the first device may be located in a first xy plane of the first coordinate system, wherein the antenna array of the second device may be located in a second xy plane of the second coordinate system, the second xy plane being parallel to the first xy plane, wherein the origin of the second coordinate system may be located on the z-axis of the first coordinate system, wherein a parallel shift of the second antenna array is in the second xy plane, wherein the first pilot signal may be a constant phase pilot signal, wherein estimating the parallel shift includes estimating at least one of a parallel shift along an x-axis of the second xy plane by estimating a rotation of the second antenna array relative to an x-axis of the second xy plane (X rotation) or estimating a parallel shift along a y-axis of the second xy plane by estimating a rotation of the second antenna array relative to a y-axis of the second xy plane (Y rotation), wherein the estimation is based on the received first pilot signal. In some aspects, estimating the parallel shift may include converting at least one of the estimated X rotation and Y rotation of the second antenna array into a parallel shift.

[0253] In a fourth aspect, estimating at least one of an X-rotation and a Y-rotation of the second antenna array may be based on determining a phase of a received first pilot signal on an antenna of the second antenna array.

[0254] In a fifth aspect, estimating at least one of an X-rotation and a Y-rotation of the second antenna array may be based on determining at least one phase difference between two adjacent antennas in the second antenna array.

[0255] In a sixth aspect, process 1200 may include determining a linear phase slope based on at least one of: averaging multiple estimates of the phase difference between corresponding two adjacent antennas in the second antenna array along an x-axis of a second xy plane, or averaging multiple estimates of the phase difference between corresponding two adjacent antennas in the second antenna array along a y-axis of the second xy plane.

[0256] In the seventh aspect, the x-axis of the first xy plane and the x-axis of the second xy plane may be parallel, or the y-axis of the first xy plane and the y-axis of the second xy plane may be parallel.

[0257] In an eighth aspect, estimating at least one of an X rotation and a Y rotation of the second antenna array may be based on determining a linear phase slope.

[0258] In a ninth aspect, estimating the parallel shift may be based on determining a linear phase slope.

[0259] In a tenth aspect, estimating the parallel shift may include converting an estimated X and / or Y rotation of the second antenna array into a parallel shift.

[0260] In an eleventh aspect, at least the first pilot signal may be a linear phase ramp pilot signal, and estimating the parallel shift may include a direct estimate of the parallel shift, wherein the direct estimate is based on determining an inner product between a pilot signal received at an antenna of a second antenna array and a pilot signal based on one or more hypothetical projections of the antenna array shift.

[0261] In the twelfth aspect, the first pilot signal may be a linear phase ramp pilot signal.

[0262] In the thirteenth aspect, the second pilot signal may be a linear phase ramp pilot signal.

[0263] In some aspects, a linear phase ramp pilot signal may be used to indicate a direct shift estimation procedure.

[0264] In a fourteenth aspect, compensation can include implicit compensation with an MMSE receiver.For example, instead of applying a post-processor matrix, the receiver can apply MMSE filtering to estimate the transmitted data symbols.

[0265] In a fifteenth aspect, compensating may include beam steering based on applying the estimated parallel shift to a post-processing matrix.

[0266] In a sixteenth aspect, process 1200 may include: receiving a (e.g., first) indication from a first device for estimating a distance relative to a first antenna array of the first device and a second antenna array of the second device; and estimating a distance relative to the first antenna array of the first device and the second antenna array of the second device.

[0267] In a seventeenth aspect, process 1200 may include sending feedback to the first device based on the estimated distance.

[0268] In an eighteenth aspect, process 1200 may include receiving, from a first device, a (eg, second) indication for estimating a parallel shift by estimating at least one of an X and Y rotation of a second device, wherein the indication is based on a constant phase first pilot signal.

[0269] In a nineteenth aspect, process 1200 may include receiving, from a first device, a (eg, second) indication for estimating a parallel shift by direct estimation, wherein the indication is based on a linear phase ramp first pilot signal.

[0270] In particular, the pilot type (constant phase pilot or linear phase ramp pilot) can be used to indicate the type of estimation procedure.

[0271] In a twentieth aspect, the indication may be based on an estimated distance relative to a first antenna array of the first device and a second antenna array of the second device.

[0272] In a twenty-first aspect, process 1200 may include receiving an indication of the first pilot signal (indicating a constant phase pilot or a linear phase ramp pilot) via radio resource control (RRC) signaling prior to receiving the first pilot signal.

[0273] although Fig.12 An example block diagram of process 1200 is shown, but in some aspects, process 1200 may include Fig.12 Additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in the process 1200. Additionally or alternatively, two or more of the blocks in the process 1200 may be performed in parallel.

[0274] Fig.13 1 is a block diagram of an example device 1300 for wireless communications related to LOS MIMO. Note that the terms device and apparatus are used interchangeably. Device 1300 may be a first device or a transmitting device (e.g., Figure 1 105a or relay 105d, etc.) as shown. Device 1300 may include a receiving component 1302, a communication manager 1308, and a sending component 1304. Device 1300 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0275] The communication manager 1308 or its subcomponents may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functionality of the communication manager 1308 or its subcomponents may be implemented by a general purpose processor, DSP, application specific integrated circuit (ASIC), FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions, processors, or methods described in the present disclosure.

[0276] The communication manager 1308 or its subcomponents may be physically located at various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the communication manager 1308 or its subcomponents may be independent and distinct components in accordance with various aspects of the present disclosure. In some examples, in accordance with various aspects of the present disclosure, the communication manager 1308 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0277] In some aspects, device 1300 may be configured to perform Figure 5 Additionally or alternatively, the device 1300 may be configured to perform one or more processes described herein, such as Fig.11 In addition or alternatively, one or more components in a set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or codes stored in a non-transitory computer-readable medium, and the instructions or codes may be executed by a controller or processor to perform the function or operation of the component.

[0278] The receiving component 1302 may receive communications, such as reference signals, control information, data communications, or combinations thereof, from the device 1306. The receiving component 1302 may provide the received communications to one or more other components of the device 1300. In some aspects, the receiving component 1302 may perform signal processing (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, demapping, equalization, interference cancellation, or decoding, etc.) on the received communications and may provide the processed signals to one or more other components of the device 1306. In some aspects, the receiving component 1302 may include one or more antennas, demodulators, MIMO detectors, receive processors, controllers / processors, memory, or combinations thereof.

[0279] In some examples, receiving component 1302 may receive feedback from another device based on an estimated misalignment of the antenna array of the other device relative to the antenna array of the present device 1300 .

[0280] The transmission component 1304 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the device 1306. In some aspects, one or more other components of the device 1306 may generate communications and may provide the generated communications to the transmission component 1304 for transmission to the device 1306. In some aspects, the transmission component 1304 may perform signal processing (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, etc.) on the generated communications and may transmit the processed signals to the device 1306. In some aspects, the transmission component 1304 may include one or more antennas, modulators, transmit MIMO processors, transmit processors, controllers / processors, memories, or a combination thereof. The communication manager 1308 may determine inter-aperture orthogonality information corresponding to a plurality of aperture pairs. In some aspects, the communication manager 1308 may include a controller / processor, a memory, or a combination thereof. In some examples, the transmission component 1304 may transmit a first pilot signal, wherein the first pilot signal may be at least one of a constant phase pilot signal or a linear phase ramp pilot signal.

[0281] Fig.13 The number and arrangement of components shown are provided as examples. In practice, there may be Fig.13 The components shown may include additional components, fewer components, different components, or components arranged in a different manner. Fig.13 Two or more components shown may be implemented in a single component, or Fig.13 A single component shown may be implemented as multiple distributed components.

[0282] Additionally or alternatively, Fig.13 The illustrated set (one or more) of components may be described as being executable by Fig.13 Another group of components shown performs one or more functions.

[0283] Fig.14 1 is a block diagram of an example device 1400 for wireless communications related to LOS MIMO. Note that the terms device and apparatus are used interchangeably. Device 1400 may be an example second device or receiving device as described herein (e.g., Figure 1 UE 115, base station 105a, or relay 105d, etc. as shown). Device 1400 may include a receiving component 1402, a communication manager 1408, and a sending component 1404. Device 1400 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0284] The communication manager 1408 or its subcomponents may be implemented in hardware, in code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functionality of the communication manager 1408 or its subcomponents may be implemented by a general purpose processor, a DSP, an application specific integrated circuit (ASIC), an FPGA or other programmable logic device designed to perform the functions described in the present disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0285] The communication manager 1408 or its subcomponents may be physically located at various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the communication manager 1408 or its subcomponents may be independent and distinct components according to various aspects of the present disclosure. In some examples, according to various aspects of the present disclosure, the communication manager 1408 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0286] In some aspects, device 1400 may be configured to perform Figure 5 Additionally or alternatively, the device 1400 may be configured to perform one or more processes described herein, such as Fig.12 In addition or alternatively, one or more components in a set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium, and the instructions or code may be executed by a controller or processor to perform the function or operation of the component.

[0287] The receiving component 1402 may receive communications from the device 1406, such as reference signals, control information, data communications, or a combination thereof. The receiving component 1402 may provide the received communications to one or more other components of the device 1400. In some aspects, the receiving component 1402 may perform signal processing (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, demapping, equalization, interference cancellation or decoding, etc.) on the received communications, and may provide the processed signals to one or more other components of the device 1306. In some aspects, the receiving component 1302 may include one or more antennas, demodulators, MIMO detectors, receiving processors, controllers / processors, memories, or a combination thereof. In some examples, the receiving component 1402 receives a first pilot signal from another device, wherein the first pilot signal may be at least one of a constant phase pilot signal or a linear phase ramp pilot signal.

[0288] The transmitting component 1404 may transmit communications, such as reference signals, control information, data communications, or combinations thereof, to the device 1406. In some aspects, one or more other components of the device 1406 may generate communications and may provide the generated communications to the transmitting component 1404 for transmission to the device 1406. In some aspects, the transmitting component 1404 may perform signal processing (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, etc.) on the generated communications and may transmit the processed signals to the device 1406. In some aspects, the transmitting component 1404 may include one or more antennas, modulators, transmit MIMO processors, transmit processors, controllers / processors, memories, or combinations thereof. The communication manager 1408 may determine inter-aperture orthogonality information corresponding to a plurality of aperture pairs. In some aspects, the communication manager 1408 may include a controller / processor, memories, or combinations thereof.

[0289] In some examples, transmitting component 1404 may send feedback to another device based on an estimated misalignment of the antenna array of device 1400 relative to the antenna array of the other device.

[0290] In some examples, the transmitting component may transmit a second pilot signal to another device, where the second pilot signal may be at least one of a constant phase pilot signal or a linear phase ramp pilot signal.

[0291] Fig.14 The number and arrangement of components shown in the figure are provided as examples. In practice, there may be Fig.14 The components shown in the figure may include additional components, fewer components, different components, or components arranged in a different manner. Fig.14 Two or more components shown in may be implemented in a single component, or Fig.14A single component shown in may be implemented as multiple distributed components.

[0292] Additionally or alternatively, Fig.14 The illustrated set (one or more) of components may be described as being executable by Fig.14 Another group of components shown performs one or more functions.

[0293] The various operations of the above methods may be performed by any suitable components capable of performing the corresponding functions. The components may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally speaking, where there are operations illustrated in the accompanying drawings, those operations may have corresponding corresponding components plus functional components with similar numbers.

[0294] The examples described above in the detailed description set forth in conjunction with the accompanying drawings do not represent the only examples that can be implemented or within the scope of the claims. The term "example" or "exemplary" when used in this specification means "used as an example, instance, or illustration" and does not mean "better than" or "better than other examples". The specific implementation includes specific details to provide an understanding of the described technology. However, these technologies can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0295] 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 mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0296] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an ASIC, an 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 an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. Additionally or alternatively, the processor may be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0297] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium, or sent via a computer-readable medium. Other examples and specific implementations fall within the scope and essence of the present disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or any combination thereof. The features that implement the functions may be physically located in various locations, including being distributed so that the parts of the functions are implemented at different physical locations. As used herein, including in the claims, the term "or" when used in a list of two or more items means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as comprising components A, B, or C, the composition may comprise a single A; a single B; a single C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Also, as used herein, including in the claims, “or” as used in a list of items (e.g., a list of items followed by a phrase such as “at least one of” or “one or more of”) indicates a separated list, so that, for example, a list of “at least one of A, B, or C” means: A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0298] Computer-readable medium includes both computer storage medium and communication medium, and these communication mediums include any medium that promotes computer program to be transferred from one place to another place. Storage medium can be any available medium that can be accessed by general or special-purpose computer. By way of example and not limitation, computer-readable medium can include RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used for carrying or storing the desired program code unit with the form of instruction or data structure and any other medium that can be accessed by general or special-purpose computer or general or special-purpose processor. Moreover, any connection is appropriately referred to as computer-readable medium. For example, if software is to be sent from website, server or other remote source using coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer readable media.

[0299] The previous description of the disclosure is provided to enable those skilled in the art to implement or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Therefore, the disclosure is not limited to the examples and designs described herein, but is given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication for line-of-sight multiple-input multiple-output (LOS MIMO) by a first device, comprising: Sending a first pilot signal to a second device; The first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

2. The method according to claim 1, further comprising: Feedback is received from the second device based on the estimated misalignment of the second antenna array relative to the first antenna array.

3. The method according to claim 1, further comprising: receiving a second pilot signal from the second device, wherein the second pilot is at least one of a constant phase pilot or a linear phase ramp pilot; as well as estimating a misalignment of the first antenna array of the first device relative to the second antenna array of the second device; Wherein estimating the misalignment comprises: estimating a parallel displacement of the first antenna array relative to the second antenna array; as well as The estimated misalignment of the first antenna array is compensated.

4. The method of claim 3, wherein the antenna array of the first device is located in a first xy plane of a first coordinate system; wherein the antenna array of the second device is located in a second xy plane of a second coordinate system, the second xy plane is parallel to the first xy plane, and wherein the origin of the second coordinate system is located on the z-axis of the first coordinate system; wherein said parallel displacement of said first antenna array is in said first xy plane; wherein at least one of the first pilot signal or the second pilot signal is the constant phase pilot; Wherein estimating the parallel shift comprises at least one of: estimating an x-rotation of the first antenna array relative to an x-axis of the first xy plane, or estimating a Y rotation of the first antenna array relative to a y-axis of the first xy plane; Wherein estimating the parallel shift further comprises converting the estimated X rotation or Y rotation of the first antenna array into the parallel shift. 5 . The method of claim 4 , wherein estimating at least one of an X-rotation and a Y-rotation of the first antenna array is based on determining at least one phase difference between two adjacent antennas in the first antenna array.

6. The method according to claim 5, further comprising: The linear phase ramp is determined based on at least one of: averaging a plurality of estimates of the phase difference between corresponding two adjacent antennas in the first antenna array along an x-axis of the first xy plane, or A plurality of estimates of phase differences between corresponding two adjacent antennas in the first antenna array along a y-axis of the first xy plane are averaged.

7. The method according to claim 3, wherein at least one of the first pilot signal or the second pilot signal is the linear phase ramp pilot, wherein estimating the parallel shift comprises direct estimation of the parallel shift; Wherein the direct estimation is based on determining an inner product between pilot signals received at antennas of the first antenna array and pilot signals projected based on one or more hypotheses of antenna array shifts.

8. The method of claim 3, wherein compensating comprises beam steering based on applying the estimated parallel shift to a pre-decoder matrix.

9. The method according to claim 1, further comprising: sending, to the second device, a first indication for estimating a distance between the first antenna array of the first device and the second antenna array of the second device; as well as Feedback is received from the second device based on the estimated distance.

10. The method according to claim 9, further comprising: sending a second indication to the second device for estimating the parallel shift by estimating at least one of an X rotation of the second antenna array relative to an x-axis of a second xy plane or a Y rotation of the second antenna array relative to a y-axis of the second xy plane, wherein the antenna array of the second device is located in the second xy plane of a second coordinate system; The second indication is based on the constant phase first pilot signal.

11. The method according to claim 9, further comprising: sending a second instruction to the second device for estimating the parallel shift by direct estimation, The second indication is based on the linear phase ramp first pilot signal.

12. The method according to claim 1, further comprising: Prior to sending the first pilot signal, an indication of the first pilot signal is sent to the second device via radio resource control (RRC) signaling.

13. The method according to claim 9, further comprising: when the estimated distance is below a certain threshold, sending a second indication for estimating the parallel shift by estimating at least one of an X rotation of the second antenna array relative to an x-axis of a second xy plane or a Y rotation of the second antenna array relative to a y-axis of the second xy plane, wherein the antenna array of the second device is located in the second xy plane of a second coordinate system; or When the estimated distance is above a certain threshold, a second indication for estimating the parallel shift by direct estimation is sent.

14. A method for wireless communication for line-of-sight multiple-input multiple-output (LOS MIMO) by a second device, comprising: receiving a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot; A misalignment of a second antenna array of the second device relative to a first antenna array of the first device is estimated.

15. The method according to claim 14, further comprising: Feedback is sent to the first device based on the estimated misalignment of the second antenna array relative to the first antenna array.

16. The method of claim 14, wherein estimating the misalignment comprises estimating a parallel shift of the second antenna array relative to the first antenna array.

17. The method according to claim 14, further comprising: The estimated misalignment of the second device is compensated.

18. The method according to claim 14, further comprising: A second pilot signal is sent to the first device for estimating a misalignment of the first antenna array of the first device relative to the second antenna array of the second device.

19. The method of claim 18, wherein the second pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot.

20. The method according to claim 14, wherein estimating the misalignment comprises estimating a parallel shift of the second antenna array relative to the first antenna array; wherein the antenna array of the first device is located in a first xy plane of a first coordinate system; wherein the antenna array of the second device is located in a second xy plane of a second coordinate system, the second xy plane is parallel to the first xy plane, and wherein the origin of the second coordinate system is located on the z-axis of the first coordinate system; wherein said parallel displacement of said second antenna array is in said second xy plane; wherein at least the first pilot signal is a constant phase pilot; Wherein estimating the parallel shift comprises at least one of: estimating an x-rotation of the second antenna array relative to an x-axis of the second xy plane, or estimating a Y rotation of the second antenna array relative to a y-axis of the second xy plane; and Wherein estimating the parallel shift further comprises converting at least one of an estimated X-rotation and a Y-rotation of the second antenna array into the parallel shift.

21. The method of claim 20, wherein estimating the at least one of an X-rotation and a Y-rotation of the second antenna array is based on determining at least one phase difference between two adjacent antennas in the second antenna array.

22. The method according to claim 21, further comprising: The linear phase ramp is determined based on at least one of: averaging a plurality of estimates of the phase difference between corresponding two adjacent antennas in the second antenna array along an x-axis of the second xy plane; or A plurality of estimates of phase differences between corresponding two adjacent antennas in the second antenna array along a y-axis of the second xy plane are averaged.

23. The method according to claim 14, wherein at least the first pilot signal is a linear phase ramp pilot; wherein estimating the misalignment comprises estimating a parallel shift of the second antenna array relative to the first antenna array; wherein estimating the parallel shift comprises direct estimation of the parallel shift, Wherein the direct estimation is based on determining an inner product between linear phase ramped pilots received at antennas of the second antenna array and linear phase ramped pilots projected based on one or more hypotheses of antenna array shifts.

24. The method of claim 14, further comprising: The estimated misalignment of the second device is compensated, wherein the compensation comprises beam steering based on applying the estimated parallel shift to a post-processing matrix.

25. The method of claim 14, further comprising: receiving, from the first device, a first indication for estimating a distance between the first antenna array of the first device and the second antenna array of the second device; estimating the distance relative to the first antenna array of the first device and the second antenna array of the second device; as well as Feedback is sent to the first device based on the estimated distance.

26. The method according to claim 25, wherein estimating the misalignment comprises estimating a parallel shift of the second antenna array relative to the first antenna array; And the method further comprises: receiving from the first device a second indication for estimating the parallel shift by estimating at least one of an X rotation of the second antenna array relative to an x-axis of a second xy plane or a Y rotation of the second antenna array relative to a y-axis of the second xy plane, wherein the second antenna array of the second device is located in the second xy plane of a second coordinate system; The second indication is based on the constant phase first pilot signal.

27. The method of claim 25, wherein estimating the misalignment comprises estimating a parallel shift of the second antenna array relative to the first antenna array; and The method further comprises: receiving from the first device a second indication for estimating the parallel shift by direct estimation, The second indication is based on the linear phase ramp first pilot signal.

28. The method of claim 14, further comprising: An indication of the first pilot signal is received via radio resource control (RRC) signaling prior to receiving the first pilot signal.

29. An apparatus for wireless communication of a first device for line-of-sight (LOS) MIMO, comprising: processor, a memory in electronic communication with the processor, and instructions stored in the memory, wherein the instructions are executable by the processor to cause the apparatus to: A first pilot signal is sent to a second device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot for estimating misalignment of a second antenna array of the second device relative to a first antenna array of the first device.

30. An apparatus for wireless communication of a second device for line-of-sight (LOS) MIMO, comprising: processor, a memory in electronic communication with the processor, and instructions stored in the memory, wherein the instructions are executable by the processor to cause the apparatus to: receiving a first pilot signal from a first device, wherein the first pilot signal is at least one of a constant phase pilot or a linear phase ramp pilot; as well as A misalignment of a second antenna array of the second device relative to a first antenna array of the first device is estimated.

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