Over-the-Air(OTA) Channel Equalization in Millimeter-Wave Testing.

Abstract

A wireless communication system and method for over-the-air (OTA) channel equalization in millimeter wave (mmWave) testing are provided. An apparatus transmits one or more reference signals to a wireless communication device located in the over-the-air (OTA) space. The apparatus receives channel state information from the wireless communication device in response to the one or more reference signals. The apparatus determines a channel estimate for the OTA space based on the received channel state information. The apparatus transmits a communication signal to the wireless communication device based on the reference channel and the channel estimate for the OTA space.

Description

[Technical field]

[0001] This application relates to wireless communication systems, and more particularly to over-the-air (OTA) channel equalization in millimeter wave (mmWave) testing. [Background technology]

[0002] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasts, etc. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). A wireless multiple-access communication system may include several base stations (BSs), each simultaneously supporting communication for multiple communication devices, which may in some cases be known as user equipment (UE).

[0003] To meet the growing demand for enhanced mobile broadband connectivity, wireless communications technologies are evolving from Long Term Evolution (LTE) technology to next-generation New Radio (NR) technology, sometimes referred to as fifth generation (5G). For example, NR is designed to provide lower latency, higher bandwidth or throughput, and higher reliability than LTE. NR is designed to operate across a wide range of spectrum bands, for example, low frequency bands below about 1 gigahertz (GHz) and intermediate frequency bands from about 1 GHz to about 6 GHz, to higher frequency bands such as mmWave bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed spectrum and shared spectrum. Spectrum sharing allows operators to opportunistically aggregate spectrum to dynamically support high-bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0004] Before NR, performance testing of wireless communication devices is performed using conducted test methods, where the radio transmitter and radio receiver are directly connected using a radio frequency (RF) cable and an antenna connector. However, conducted antenna connectors are not available for mmWave wireless communication devices due to the need for high frequency and directional testing. Therefore, OTA testing can be applied to testing wireless communication devices operating at mmWave frequencies. Summary of the Invention [Means for solving the problem]

[0005] The following summarizes some aspects of the present disclosure in order to provide a basic understanding of the described technology. This summary is not an extensive overview of all contemplated features of the present disclosure, nor does it identify key or critical elements of all aspects of the present disclosure, nor does it delineate the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in summary form as a prelude to the more detailed description that is presented later.

[0006] For example, in one aspect of the disclosure, a method of wireless communication includes transmitting, by an apparatus, one or more reference signals to a wireless communication device located in an over-the-air (OTA) space; receiving, by the apparatus, channel state information from the wireless communication device in response to the one or more reference signals; determining, by the apparatus, a channel estimate for the OTA space based on the received channel state information; and transmitting, by the apparatus, a communication signal to the wireless communication device based on the reference channels and the channel estimate for the OTA space.

[0007] In an additional aspect of the disclosure, an apparatus includes a transceiver configured to transmit one or more reference signals to a wireless communication device located in an over-the-air (OTA) space, receive channel state information from the wireless communication device in response to the one or more reference signals, and transmit a communication signal to the wireless communication device based on the reference channels and a channel estimate of the OTA space, and a processor configured to determine a channel estimate of the OTA space based on the received channel state information.

[0008] In an additional aspect of the disclosure, a non-transitory computer readable medium has program code recorded thereon, the program code including code for causing an apparatus to transmit one or more reference signals to a wireless communication device located in an over-the-air (OTA) space, code for causing the apparatus to receive channel state information from the wireless communication device in response to the one or more reference signals, code for causing the apparatus to determine a channel estimate for the OTA space based on the received channel state information, and code for causing the apparatus to transmit a communication signal to the wireless communication device based on the reference channels and the channel estimate for the OTA space.

[0009] In an additional aspect of the disclosure, an apparatus includes means for transmitting one or more reference signals to a wireless communication device located in an over-the-air (OTA) space, means for receiving channel state information from the wireless communication device in response to the one or more reference signals, means for determining a channel estimate for the OTA space based on the received channel state information, and means for transmitting a communication signal to the wireless communication device based on the reference channels and the channel estimate for the OTA space.

[0010] Other aspects, features, and embodiments of the present invention will be apparent to those skilled in the art upon reviewing the following description of certain exemplary embodiments of the present invention in conjunction with the accompanying figures. Features of the present invention may be described in conjunction with some embodiments and figures below, but all embodiments of the present invention may include one or more of the advantageous features described herein. In other words, one or more embodiments may be described as having some advantageous features, but one or more of such features may be used in accordance with various embodiments of the present invention described herein. Similarly, exemplary embodiments may be described below as device embodiments, system embodiments, or method embodiments, but it should be understood that such exemplary embodiments may be implemented in various devices, systems, and methods. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 illustrates a wireless communication network in accordance with certain aspects of the present disclosure. [Diagram 2] FIG. 2 illustrates a radio frame structure in accordance with certain aspects of the present disclosure. [Diagram 3] FIG. 1 illustrates a millimeter wave (mmWave) wireless communication device test setup in accordance with certain aspects of the present disclosure. [Figure 4] FIG. 1 is a block diagram of a user equipment (UE) in accordance with certain aspects of the present disclosure. [Diagram 5] FIG. 2 is a block diagram of an example network device according to certain aspects of the present disclosure. [Figure 6] FIG. 1 is a signaling diagram of an mmWave wireless communication device testing method according to certain aspects of the present disclosure. [Figure 7] 1 is a flow diagram of a mmWave wireless communication device testing method according to certain aspects of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The detailed description set forth below with reference to the accompanying drawings describes various configurations and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0013] The present disclosure generally relates to wireless communication systems, also referred to as wireless communication networks. In various embodiments, the techniques and devices may be used in wireless communication networks, such as Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single Carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, Fifth Generation (5G) or New Radio (NR) networks, and other communication networks. The terms "network" and "system" described herein may be used interchangeably.

[0014] OFDMA networks may implement radio technologies such as Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, Flash OFDM, etc. UTRA, E-UTRA, and GSM are parts of the Universal Mobile Telecommunications System (UMTS). In particular, Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These various radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define globally applicable third generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the UMTS mobile phone standard. 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. This disclosure relates to the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond, which involve shared access to the wireless spectrum between networks using a series of new, different radio access technologies or radio air interfaces.

[0015] In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified air interface. To achieve these goals, further enhancements to LTE and LTE-A are considered, in addition to the development of new radio technologies for 5G NR networks. 5G NR is a service-oriented network that is expected to achieve the following: (1) ultra-high density (e.g., approximately one million nodes / km); 2), ultra-low complexity (e.g., on the order of tens of bits per second), ultra-low energy (e.g., on the order of 10 years battery life), and deep coverage with the ability to reach difficult locations; (2) to the Massive Internet of Things (IoT) with strong security to protect sensitive personal, financial, or confidential information, ultra-high reliability (e.g., on the order of 99.9999% reliability), ultra-low latency (e.g., on the order of 1 ms), and mission-critical control with users with or without widespread mobility; and (3) ultra-high capacity (e.g., on the order of 10 Tbps / km 2 ), extreme data rates (e.g., multi-Gbps rates, user experience rates of 100 Mbps or more), and a deep understanding of advanced discovery and optimization, with enhanced mobile broadband.

[0016] 5G NR has a common flexible framework for efficient multiplexing of services and features with dynamic low latency time division duplexing (TDD) / frequency division duplexing (FDD) design with scalable numerology and transmission time interval (TTI), and may be implemented using optimized OFDM-based waveforms with advanced wireless technologies such as massive multiple input multiple output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of numerology in 5G NR with the scaling of subcarrier spacing may efficiently address the operation of diverse services across diverse spectrum and diverse deployments. For example, in various outdoor macro coverage deployments of sub-3 GHz FDD / TDD implementations, subcarrier spacing may occur at 15 kHz over bandwidths (BWs) of, for example, 5, 10, 20 MHz, etc. For various other outdoor small cell coverage deployments with TDD over 3 GHz, the subcarrier spacing may occur at 30 kHz over 80 / 100 MHz BW. For various other indoor wideband implementations using TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur at 60 kHz over 160 MHz BW. Finally, for various deployments transmitting with mmWave components at 28 GHz TDD, the subcarrier spacing may occur at 120 kHz over 500 MHz BW.

[0017] 5G NR's scalable numerology facilitates scalable TTIs for diverse latency and quality of service (QoS) requirements. For example, shorter TTIs may be used for low latency and high reliability, while longer TTIs may be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmissions to begin on symbol boundaries. 5G NR also contemplates a self-contained, unified subframe design with UL / downlink scheduling information, data, and acknowledgments in the same subframe. The self-contained, unified subframe supports communication in unlicensed or contention-based shared spectrum, adaptive UL / downlink that can be flexibly configured per cell to dynamically switch between UL and downlink to meet current traffic needs.

[0018] Various other aspects and features of the present disclosure are further described below. It will be apparent that the teachings herein can be embodied in a wide variety of forms, and that any particular structure, function, or both disclosed herein are merely representative and not limiting. Based on the teachings herein, a person skilled in the art will appreciate that an aspect disclosed herein can be implemented independently of any other aspect, and that two or more of these aspects can be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects described herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structures, functions, or structures and functions in addition to or other than one or more of the aspects described herein. For example, a method may be implemented as part of a system, device, apparatus, and / or as instructions stored on a computer-readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim.

[0019] NR may specify various test cases to test UEs for conformance and / or performance. Traditional conducted RF test methods use well-behaved, predictable transmission lines, such as RF cables and antenna connectors between test equipment and the device under test (DUT). For mmWave testing, OTA connections are used instead of RF cables and antenna connectors. To ensure a well-controlled RF environment for OTA testing, the OTA connections may be managed inside an anechoic chamber. However, OTA connections may introduce quasi-static channel characteristics into the test signal transmission path, making test measurements inaccurate and / or degrading.

[0020] This application describes a mechanism for OTA channel equalization in mmWave testing. For example, the test equipment may emulate the operation of a base station (BS) to transmit one or more reference signals, such as a synchronization signal block (SSB) including a synchronization signal (e.g., a secondary synchronization signal (SSS)) and a channel state information reference signal (CSI-RS), to a user equipment (UE) located in an OTA test chamber. The UE may report channel state information based on the one or more reference signals. The channel state information may include reference signal received power per branch (RSRPB) and reference signal antenna relative phase (RSARP). RSRPB may refer to received signal power per polarization. RSARP may refer to the relative phase between two antenna ports (e.g., between a first receive antenna port and a second receive antenna port) at the UE. The test equipment may determine a channel response of an OTA connection or OTA space between the UE and the test equipment based on the RSRPB and RSARP reported by the UE. The test equipment may determine a channel equalizer to equalize the channel effects of the OTA connection based on the estimated OTA channel response. The test equipment may generate a test signal and apply the equalizer to the test signal before transmitting it to the UE for testing. In other words, the equalizer pre-compensates the test signal such that the test signal received at the UE does not include the channel characteristics of the OTA channel or at least includes a minimal amount of distortion from the OTA channel.

[0021] Aspects of the present disclosure may provide several advantages. For example, applying OTA channel equalization during test signal generation may improve the accuracy of test measurements using OTA tests (e.g., for UE demodulation tests). Using CSI-RS in addition to SSS for channel measurement and reporting allows for more accurate estimation of the OTA channel, which in turn allows for a more accurate OTA channel equalizer.

[0022] FIG. 1 illustrates a wireless communication network 100 according to some aspects of the disclosure. The network 100 may be a 5G network. The network 100 includes several base stations (BSs) 105 (individually labeled as 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. The BSs 105 may be stations that communicate with UEs 115 and may also be referred to as evolved Node Bs (eNBs), next generation eNBs (gNBs), access points, etc. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to this particular geographic coverage area of ​​the BS 105 and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0023] The BS 105 may provide communication coverage for a macro cell, or a small cell, such as a pico cell or femto cell, and / or other types of cells. A macro cell will generally cover a relatively large geographic area (e.g., a few kilometers in radius) and may allow unrestricted access by UEs with a service subscription with the network provider. A small cell, such as a pico cell, will generally cover a relatively small geographic area and may allow unrestricted access by UEs with a service subscription with the network provider. A small cell, such as a femto cell, will also generally cover a relatively small geographic area (e.g., a home) and may provide unrestricted access as well as restricted access by UEs with an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS, or a home BS. In the example shown in FIG. 1, BSs 105d and 105e may be regular macro BSs, while BSs 105a-105c may be macro BSs capable of one of three-dimensional (3D), full-dimensional (FD), or massive MIMO. BSs 105a-105c may utilize their higher-dimensional MIMO capabilities to increase coverage and capacity by leveraging 3D beamforming in both elevation and azimuth beamforming. BS 105f may be a small cell BS that may be a home node or a portable access point. BS 105 may support one or multiple (e.g., two, three, four, etc.) cells.

[0024] Network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing and transmissions from different BSs may not be aligned in time.

[0025] The UEs 115 are distributed throughout the wireless network 100, and each UE 115 may be fixed or mobile. The UEs 115 may also be referred to as terminals, mobile stations, subscriber units, stations, etc. The UEs 115 may be cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, tablet computers, laptop computers, cordless phones, wireless local loop (WLL) stations, etc. In one aspect, the UEs 115 may be devices that include a universal integrated circuit card (UICC). In another aspect, the UEs may be devices that do not include a UICC. In some aspects, the UEs 115 that do not include a UICC may also be referred to as IoT devices or internet of everything (IoE) devices. The UEs 115a-115d are examples of mobile smartphone type devices that access the network 100. The UEs 115 may also be machines that are specifically configured for connected communications, including machine type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc. UEs 115e-115h are examples of various machines configured for communication to access network 100. UEs 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication to access network 100. UE 115 may be able to communicate with any type of BS, whether a macro BS, small cell, etc. In FIG. 1 , the lightning bolts (e.g., communication links) indicate wireless transmissions between UE 115 and a serving BS 105, which is a BS designated to serve UE 115 on the downlink (DL) and / or uplink (UL), desired transmissions between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UEs 115.

[0026] In operation, the BSs 105a-105c may serve the UEs 115a and 115b using 3D beamforming and coordinated spatial techniques such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 105d may perform backhaul communications with the BSs 105a-105c as well as the small cell BS 105f. The macro BS 105d may also transmit multicast services to which the UEs 115c and 115d subscribe and are received by the UEs 115c and 115d. Such multicast services may include mobile television or stream video, or other services for providing local community information, such as weather emergencies or alerts such as amber or grey alerts.

[0027] The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (which may be an example of a gNB or an access node controller (ANC) for example) may interface with the core network through backhaul links (e.g., NG-C, NG-U, etc.) and may perform radio configuration and scheduling for communications with the UEs 115. In various examples, the BSs 105 may communicate with each other either directly or indirectly (e.g., through the core network) via backhaul links (e.g., X1, X2, etc.), which may be wired or wireless communications links.

[0028] Network 100 may also support mission-critical communications with ultra-reliable redundant links for mission-critical devices such as UE 115e, which may be a drone. The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, as well as links from small cell BS 105f. Other machine-type devices such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device) may communicate through network 100 either directly with BSs such as small cell BS 105f and macro BS 105e, or in a multi-step size configuration by communicating with another user device that relays temperature measurement information to the network, such as UE 115f communicating temperature measurement information to UE 115g, which is a smart meter, that is subsequently reported to the network through small cell BS 105f. The network 100 may also provide further network efficiency through dynamic, low latency TDD / FDD communications, such as V2V communications, V2X communications, C-V2X communications between the UE 115i, 115j, or 115k and other UEs 115, and / or vehicle-to-infrastructure (V2I) communications between the UE 115i, 115j, or 115k and the BS 105.

[0029] In some implementations, the network 100 utilizes an OFDM-based waveform for communication. An OFDM-based system may partition a system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, etc. Each subcarrier may be modulated with data. In some cases, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system BW. The system BW may also be partitioned into subbands. In other cases, the subcarrier spacing and / or the duration of the TTI may be scalable.

[0030] In some aspects, the BS 105 may allocate or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) and uplink (UL) transmissions in the network 100. DL refers to the transmission direction from the BS 105 to the UE 115, and UL refers to the transmission direction from the UE 115 to the BS 105. The communication may be in the form of a radio frame. The radio frame may be divided into multiple subframes or slots, e.g., about 10. Each slot may be further divided into minislots. In an FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in the UL frequency band and a DL subframe in the DL frequency band. In a TDD mode, the UL and DL transmissions occur in different time periods using the same frequency band. For example, a subset of subframes in a radio frame (e.g., DL subframes) may be used for DL ​​transmissions, and another subset of subframes in a radio frame (e.g., UL subframes) may be used for UL transmissions.

[0031] The DL and UL subframes may be further divided into several regions. For example, each DL or UL subframe may have predefined regions for transmission of reference signals, control information, and data. The reference signals are predefined signals that facilitate communication between the BS 105 and the UE 115. For example, the reference signals may have a particular pilot pattern or structure, and the pilot tones may spread across an operating BW or frequency band, each located at a predefined time and a predefined frequency. For example, the BS 105 may transmit a cell-specific reference signal (CRS) and / or a channel state information reference signal (CSI-RS) to enable the UE 115 to estimate the DL channel. Similarly, the UE 115 may transmit a sounding reference signal (SRS) to enable the BS 105 to estimate the UL channel. The control information may include resource allocation and protocol control. The data may include protocol data and / or operational data. In some aspects, the BS 105 and the UE 115 may communicate using self-contained subframes. A self-contained subframe may include a portion for DL ​​communication and a portion for UL communication. A self-contained subframe may be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL ​​communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for DL ​​communication.

[0032] In some aspects, the network 100 may be an NR network deployed over a licensed spectrum. The BS 105 may transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BS 105 may broadcast system information (e.g., including a master information block (MIB), a remaining minimum system information (RMSI), and other system information (OSI)) associated with the network 100 to facilitate initial network access. In some instances, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) over a physical broadcast channel (PBCH) and may broadcast the RMSI and / or OSI over a physical downlink shared channel (PDSCH).

[0033] In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from the BS 105. The PSS may enable synchronization of periodic timing and may indicate a physical layer identity value. The UE 115 may then receive an SSS. The SSS may enable radio frame synchronization and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and SSS may be located in a central portion of the carrier or any suitable frequency within the carrier.

[0034] After receiving the PSS and SSS, the UE 115 may receive the MIB. The MIB may include system information for initial network access, and scheduling information for the RMSI and / or OSI. After decoding the MIB, the UE 115 may receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information regarding random access channel (RACH) procedures, paging, a control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, a physical UL control channel (PUCCH), a physical UL shared channel (PUSCH), power control, and SRS.

[0035] After acquiring the MIB, RMSI and / or OSI, the UE 115 may perform a random access procedure to establish a connection with the BS 105. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 115 may transmit a random access preamble, and the BS 105 may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, a UL grant, a temporary cell radio network temporary identifier (C-RNTI), and / or a backoff indicator. Upon receiving the random access response, the UE 115 may transmit a connection request to the BS 105, and the BS 105 may respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 115 may send a random access preamble and a connection request in a single transmission, and the BS 105 may respond by sending a random access response and a connection response in a single transmission.

[0036] After establishing the connection, the UE 115 and the BS 105 may enter a normal operation phase during which operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and / or DL ​​communication. The BS 105 may transmit UL and / or DL ​​scheduling grants to the UE 115 via a PDCCH. The scheduling grants may be transmitted in the form of DL control information (DCI). The BS 105 may transmit DL communication signals (e.g., carrying data) to the UE 115 via a PDSCH in accordance with the DL scheduling grant. The UE 115 may transmit UL communication signals to the BS 105 via a PUSCH and / or PUCCH in accordance with the UL scheduling grant.

[0037] In some aspects, the BS 105 may communicate with the UE 115 using a HARQ technique to improve communication reliability, for example, to provide a URLLC service. The BS 105 may schedule the UE 115 for PDSCH communication by transmitting a DL grant in the PDCCH. The BS 105 may transmit DL data packets to the UE 115 according to the schedule in the PDSCH. The DL data packets may be transmitted in the form of a transport block (TB). If the UE 115 successfully receives the DL data packets, the UE 115 may transmit a HARQ ACK to the BS 105. Conversely, if the UE 115 fails to successfully receive the DL transmission, the UE 115 may transmit a HARQ NACK to the BS 105. Upon receiving the HARQ NACK from the UE 115, the BS 105 may retransmit the DL data packets to the UE 115. The retransmission may include the same coded version of the DL data as the initial transmission. Alternatively, the retransmission may include a coded version of the DL data different from the initial transmission. The UE 115 may apply soft combining to combine the received coded data from the initial transmission and the retransmissions for decoding. The BS 105 and the UE 115 may also apply HARQ to the UL communication using a mechanism substantially similar to DL HARQ.

[0038] In some aspects, the network 100 may operate over a system BW or a component carrier (CC) BW. The network 100 may partition the system BW into multiple BWPs (e.g., portions). The BS 105 may dynamically assign the UE 115 to operate over a certain BWP (e.g., a certain portion of the system BW). The assigned BWP may be referred to as an active BWP. The UE 115 may monitor the active BWP for signaling information from the BS 105. The BS 105 may schedule the UE 115 for UL or DL ​​communication in the active BWP. In some aspects, the BS 105 may assign a pair of BWPs in a CC to the UE 115 for UL and DL communication. For example, the BWP pair may include one BWP for UL communication and one BWP for DL ​​communication.

[0039] FIG. 2 is a timing diagram illustrating a radio frame structure 200 according to some aspects of the disclosure. The radio frame structure 200 may be employed by a BS, such as BS 105, and a UE, such as UE 115, in a network, such as network 100, for communication. Specifically, the BS may communicate with the UE using time-frequency resources configured as shown in the radio frame structure 200. In FIG. 2, the x-axis represents time in any arbitrary units and the y-axis represents frequency in any arbitrary units. The radio frame structure 200 includes a radio frame 201. The duration of the radio frame 201 may vary depending on the aspect. In one example, the radio frame 201 may have a duration of approximately 10 milliseconds. The radio frame 201 includes M slots 202, where M may be any suitable positive integer. In one example, M may be approximately 10.

[0040] Each slot 202 includes several subcarriers 204 in frequency and several symbols 206 in time. The number of subcarriers 204 and / or the number of symbols 206 in a slot 202 may vary depending on the aspect, for example, based on the channel bandwidth, subcarrier spacing (SCS), and / or CP mode. One subcarrier 204 in frequency and one symbol 206 in time form one resource element (RE) 212 for transmission. A resource block (RB) 210 is formed from several consecutive subcarriers 204 in frequency and several consecutive symbols 206 in time.

[0041] In one example, a BS (e.g., BS 105 of FIG. 1) may schedule a UE (e.g., UE 115 of FIG. 1) for UL and / or DL ​​communications with a time granularity of a slot 202 or minislot 208. Each slot 202 may be time partitioned into K minislots 208. Each minislot 208 may include one or more symbols 206. The minislots 208 within a slot 202 may have a variable length. For example, when a slot 202 includes N symbols 206, a minislot 208 may have a length of 1 symbol 206 to (N-1) symbols 206. In some aspects, a minislot 208 may have a length of about 2 symbols 206, about 4 symbols 206, or about 7 symbols 206. In some examples, a BS may schedule a UE with a frequency granularity of a resource block (RB) 210 (e.g., including about 12 subcarriers 204).

[0042] FIG. 3 illustrates an mmWave wireless communication device test system 300 according to some aspects of the disclosure. The test system 300 may be used to test a BS, such as the BS 105, and / or a UE, such as the UE 115, for performance and / or compatibility. In particular, the test system 300 may be used to test the performance and / or compatibility of a UE operating at mmWave frequencies. For example, the test system 300 may be used for UE baseband (BB) testing, such as demodulation and CSI testing. As shown, the test system 300 includes a test platform 330 communicatively coupled to an OTA chamber 370. The test platform 330 includes a test data source 340, a baseband (BB) test equipment 350, and an RF test equipment 360. The OTA chamber 370 is a physical enclosure for RF isolation, for example, constructed from anechoic materials. A UE 315 to be tested (e.g., the UE 115) may be placed in the OTA chamber 370 such that the UE 315 may be tested in a controlled environment. The RF test equipment 360 may include a power amplifier (PA) and an antenna (e.g., an array of antenna elements and / or a probe antenna). The UE 315 may include a BB module and an RF module including a PA and an antenna. The antenna in the RF test equipment may be referred to as a test equipment antenna. The test equipment antenna is communicatively coupled to the antenna of the UE 315 via a wireless communication link in the OTA chamber 370. For example, an RF signal transmitted by the test equipment antenna is provided to the OTA chamber 370. In some aspects, the UE 315 may be positioned at various orientations or angles relative to the test equipment antenna depending on the desired test conditions. In some aspects, the test equipment antenna may also be steered or configured for different beamforming depending on the desired test conditions.

[0043] The test data source 340 may include hardware and / or software components configured to generate test payloads (e.g., data packets) that conform to a reference test protocol or test case. The test data source 340 may output the test packets in the form of test vectors 342 that include data bits.

[0044] The BB test equipment 350 is coupled to the test data source 340. The BB test equipment 350 may include hardware and / or software components. The BB test equipment 350 is configured to generate a BB signal 352 from a test vector 342. In this regard, the BB test equipment 350 encodes data bits in the test vector 342 according to a particular coding scheme and maps the encoded data bits to OFDM subcarriers (e.g., subcarriers 204) according to a particular modulation order to generate a frequency domain test signal. The BB test equipment 350 generates a time domain test signal 342 from the frequency domain test signal, for example, by applying an inverse fast Fourier transform (IFFT) and appending each OFDM symbol (e.g., symbol 206) with a cyclic prefix. In some instances, the BB test equipment 350 may also apply DFT spreading before mapping the encoded data bits to the OFDM subcarriers. In some instances, the BB test equipment 350 may apply precoding to the BB signal 352 for beamforming. The BB test equipment 350 may configure precoding based on precoding parameters specified for a particular test case. In some aspects, the BB test equipment 350 may perform operations similar to a BS, such as the BS 105.

[0045] The BB test equipment 350 is further configured to emulate various types of channel responses and / or noise based on the channel parameters 332 and / or the noise parameters 334. The channel responses may include Doppler spread, Doppler shift, delay spread, and / or any radio conditions that RF wave propagation may experience under OTA operation. Similarly, the BB test equipment 350 may emulate noise, such as additive white Gaussian noise (AWGN), phase noise, and / or any noise impairment that results in a particular signal-to-noise ratio (SNR), for testing. In some instances, the channel responses and / or noise may be specified by a conformance test standard or specification. The channel responses may include desired channel characteristics in the time domain, the frequency domain, and / or the spatial domain for conformance testing. Similarly, the noise conditions may include desired noise characteristics in the time domain, the frequency domain, and / or the spatial domain for conformance testing. The BB test equipment 350 is further configured to apply a particular channel response and / or noise to the BB signal 352 according to a particular test case.

[0046] The RF test equipment 360 is coupled to the BB test equipment 350. The RF test equipment 360 may include hardware and / or software components configured to modulate the BB signal 352 into an RF signal 362. For example, the RF test equipment 360 may include various RF components such as a mixer, a power amplifier, and / or an antenna. The RF test equipment 360 is further configured to apply various RF parameters 336 to the RF signal generation. For example, the RF parameters 336 may include an RF carrier frequency parameter, a path loss parameter, an antenna relative phase parameter, and / or any parameter related to the RF signal generation. The RF test equipment 360 is further configured to transmit the RF signal 362 to the UE under test 315 via the test equipment antenna.

[0047] In some aspects, the test procedure may be implemented by configuring the channel parameters 332, the noise parameters 334, and / or the RF parameters 336 according to a particular test case, and configuring the BB test equipment 350 and the RF test equipment 360 to generate an RF test signal 362 based on the configured channel parameters 332, the noise parameters 334, and / or the RF parameters 336. The RF test equipment 360 transmits the RF test signal 362 via a test equipment antenna, and the RF test signal 262 may be provided to the OTA chamber 370. The RF test signal 362 is received by the UE 315. The UE 315 may perform channel estimation and demodulation on the received signal 362. For conformance testing, the demodulation performance of the UE 315 may be measured and reported.

[0048] One challenge in obtaining accurate performance measurements for demodulation testing using test system 300 is that the OTA connection (between RF test equipment 360 and UE 315) may result in additional channel characteristics (indicated by OTA channel 380) in addition to the desired channel (applied in BB test equipment 350). For example, OTA channel 380 may result in quasi-static channel characteristics that may degrade demodulation performance.

[0049] For example, the BB signal received at the UE 315 on a given subcarrier (eg, subcarrier 204) may be represented as shown below: Y=H undesired ×(H desired ×P×X+N) (1) where X represents the BB test source vector (e.g., test signal 342) and H desired represents the BB channel applied by the BB test equipment 350 (e.g., based on the channel parameters 332), P represents the precoding matrix applied by the BB test equipment 350, and H undesiredrepresents an undesired channel (e.g., a quasi-static channel), and N represents the artificial noise added in the BB test equipment 350. undesired may correspond to the OTA channel 380, which may include channel characteristics provided by the RF test equipment 360 (e.g., antenna), the OTA chamber 370, and / or the RF front-end and / or insertion loss of the UE 315. During testing, the parameters X, H desired , P, and N are given.

[0050] As can be seen from equation (1), for the test case, the BB signal Y received at the UE 315 is desired In addition to the undesirable channel response H undesired In addition, the OTA connection may result in different channel effects or characteristics between the test equipment antenna and the UE's baseband, and these channel effects or characteristics may depend on the relative angle between the UE 315's antenna and the test equipment antenna. undesired may vary depending on the relative angle between the UE 315 antenna and the test equipment antenna.

[0051] Thus, this disclosure provides techniques for improving mmWave demodulation test accuracy by pre-compensating or pre-equalizing channel effects of OTA connections in RF test signals 362 at a test platform. Mechanisms for mmWave testing with OTA connection channel equalization are described in more detail herein.

[0052] 4 is a block diagram of an example UE 400 according to some aspects of the disclosure. The UE 400 may be the above-described UE 115 of FIG. 1 or the above-described UE 315 of FIG. 3. As shown, the UE 400 may include a processor 402, a memory 404, a channel measurement and reporting module 408, a test measurement module 409, a transceiver 410 including a modem subsystem 412 and a radio frequency (RF) unit 414, and one or more antennas 416. These elements may be in direct or indirect communication with each other, for example, via one or more buses.

[0053] The processor 402 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 402 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0054] The memory 404 may include cache memory (e.g., cache memory of the processor 402), random access memory (RAM), magnetoresistive RAM (MRAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory devices, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an aspect, the memory 404 includes a non-transitory computer readable medium. The memory 404 may store or have instructions 406 recorded thereon. The instructions 406 may include instructions that, when executed by the processor 402, cause the processor 402 to perform the operations described herein with reference to the UE 115 with respect to aspects of the disclosure, e.g., the aspects of FIG. 3 and FIG. 6. The instructions 406 may also be referred to as program code. The program code may be for causing the wireless communication device to perform these operations, e.g., by causing one or more processors (such as processor 402) to control or command the wireless communication device to do so. The terms "instructions" and "code" should be interpreted broadly to include any type of computer-readable statements. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or many computer-readable statements.

[0055] Each of the channel measurement and reporting module 408 and the test measurement module 409 may be implemented via hardware, software, or a combination thereof. For example, each of the channel measurement and reporting module 408 and the test measurement module 409 may be implemented as a processor, circuitry, and / or instructions 406 stored in the memory 404 and executed by the processor 402. In some examples, the channel measurement and reporting module 408 and the test measurement module 409 may be integrated within the modem subsystem 412. For example, the channel measurement and reporting module 408 and the test measurement module 409 may be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 412. In some examples, a UE may include one or both of the channel measurement and reporting module 408 and the test measurement module 409. In other examples, a UE may include all of the channel measurement and reporting module 408 and the test measurement module 409.

[0056] The channel measurement and reporting module 408 and the test measurement module 409 may be used in various aspects of the disclosure, e.g., the aspects of FIG. 3 and FIG. 6. The channel measurement and reporting module 408 is configured to receive a reference signal (e.g., SSB, SSS, CSI-RS) from a BS (e.g., BS 115) or test equipment (e.g., BB test equipment 350 and RF test equipment 360), calculate RSRPB and / or RSARP based on the reference signal, and / or transmit channel state information including RSRPB and / or RSARP to the BS or test equipment. The RSRPB and / or RSARP can facilitate OTA channel equalization, as described in more detail herein.

[0057] The test measurement module 409 is configured to receive a test signal from the test equipment, perform demodulation on the test signal, determine demodulation and / or decoding results (e.g., bit error rate or block error rate), and / or report the demodulation and / or decoding results to the test equipment.

[0058] As shown, the transceiver 410 may include a modem subsystem 412 and an RF unit 414. The transceiver 410 may be configured to communicate bidirectionally with other devices, such as the BS 105. The modem subsystem 412 may be configured to modulate and / or encode data from the memory 404 and / or the channel measurement and reporting module 408 according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 414 may be configured to process (e.g., perform analog-to-digital or digital-to-analog conversion, etc.) modulated / encoded data (e.g., PUSCH signals, PUCCH signals, channel state information, channel reports) from the modem subsystem 412 (on outbound transmissions) or for transmissions originating from another source, such as the UE 115 or the BS 105. The RF unit 414 may further be configured to perform analog beamforming along with digital beamforming. Although shown as integrated together within the transceiver 410, the modem subsystem 412 and the RF unit 414 may be separate devices coupled together in the UE 115 to enable the UE 115 to communicate with other devices.

[0059] The RF unit 414 may provide modulated and / or processed data, e.g., data packets (or, more generally, data messages that may include one or more data packets and other information), to the antenna 416 for transmission to one or more other devices. The antenna 416 may further receive data messages transmitted from other devices. The antenna 416 may provide the received data messages for processing and / or demodulation in the transceiver 410. The transceiver 410 may provide demodulated and decoded data (e.g., SSB, synchronization signals, CSI-RS, test signals) to the channel measurement and reporting module 408 for processing. The antenna 416 may include multiple antennas of similar or different designs to maintain multiple transmission links. The RF unit 414 may configure the antenna 416.

[0060] In one aspect, the UE 400 may include multiple transceivers 410 implementing different RATs (e.g., NR and LTE). In one aspect, the UE 400 may include a single transceiver 410 implementing multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 410 may include various components, where different combinations of components may implement different RATs.

[0061] 5 is a block diagram of an example communication device 500 according to some aspects of the disclosure. In some cases, the communication device 500 may be a BS 105 in the network 100 as described above in FIG. 1. In some other cases, the communication device 500 may be the BB test equipment 350 of FIG. 3 or the RF test equipment 360 of FIG. 3. As shown, the communication device 500 may include a processor 502, a memory 504, an OTA channel equalization module 509, an mmWave test module 508, a transceiver 510 including a modem subsystem 512 and an RF unit 514, and one or more antennas 516. These elements may be in direct or indirect communication with each other, for example, via one or more buses.

[0062] The processors 502 may have various characteristics as a particular type of processor. For example, they may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 502 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0063] The memory 504 may include cache memory (e.g., cache memory of the processor 502), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory 504 may include a non-transitory computer-readable medium. The memory 504 may store instructions 506. The instructions 506 may include instructions that, when executed by the processor 502, cause the processor 502 to perform operations described herein, e.g., the aspects of FIGS. 3 and 6-7. The instructions 506 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statements, as described above with respect to FIG. 4.

[0064] Each of the mmWave test module 508 and the OTA channel equalization module 509 may be implemented via hardware, software, or a combination thereof. For example, each of the mmWave test module 508 and the OTA channel equalization module 509 may be implemented as a processor, circuitry, and / or instructions 506 stored in the memory 504 and executed by the processor 502. In some examples, the mmWave test module 508 and the OTA channel equalization module 509 may be integrated within the modem subsystem 512. For example, the mmWave test module 508 and the OTA channel equalization module 509 may be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 512. In some examples, a UE may include one or both of the mmWave test module 508 and the OTA channel equalization module 509. In other examples, a UE may include all of the mmWave test module 508 and the OTA channel equalization module 509.

[0065] The mmWave testing module 508 and the OTA channel equalization module 509 may be used in various aspects of the disclosure, e.g., the aspects of Figures 3 and 6. The mmWave testing module 508 is configured to transmit reference signals (e.g., SSB, synchronization signals, and CSI-RS) to UEs (e.g., UEs 115, 315, and / or 400) located in an OTA chamber (e.g., OTA chamber 370), receive channel state information (e.g., RSRPB and RSARP) from the UEs, provide the channel state information to the OTA channel equalization module 509, and generate test signals for mmWave testing.

[0066] The OTA channel equalization module 509 is configured to determine a channel estimate for the OTA connection between the communication device 500 and the UE based on the channel state information, determine a channel equalizer for the OTA channel based on the channel estimate (e.g., to use zero-forcing techniques), and apply the OTA channel equalizer to the test signal prior to transmission to pre-compensate the test signal with the inverse of the OTA channel response. Mechanisms for OTA channel equalization in mmWave testing are described in more detail herein.

[0067] As shown, the transceiver 510 may include a modem subsystem 512 and an RF unit 514. The transceiver 510 may be configured to communicate bidirectionally with other devices, such as the UE 115 and / or 400 and / or another core network element. The modem subsystem 512 may be configured to modulate and / or encode data according to an MCS, e.g., an LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 514 may be configured to process (e.g., perform analog-to-digital or digital-to-analog conversion, etc.) modulated / encoded data (e.g., SSB, synchronization signals, CSI-RS, test signals) of transmissions originating from the modem subsystem 512 (on outbound transmissions) or from another source, such as the UE 115 and / or UE 400. The RF unit 514 may further be configured to perform analog beamforming along with digital beamforming. Although shown as integrated together within the transceiver 510, the modem subsystem 512 and / or the RF unit 514 may be separate devices coupled together at the BS 105 to enable the BS 105 to communicate with other devices.

[0068] The RF unit 514 may provide modulated and / or processed data, e.g., data packets (or, more generally, data messages that may include one or more data packets and other information), to the antenna 516 for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE 115 or 400 according to some aspects of the disclosure. The antenna 516 may further receive data messages transmitted from other devices and provide the received data messages for processing and / or demodulation in the transceiver 510. The transceiver 510 may provide demodulated and decoded data (e.g., channel state information, RSRPB, RSARP) to the mmWave test module 508 and the OTA channel equalizer module 509 for processing. The antenna 516 may include multiple antennas of similar or different designs to maintain multiple transmission links.

[0069] In one example, the transceiver 510 is configured to transmit one or more reference signals to a UE located in an OTA chamber and receive channel state information from the UE in response to the one or more reference signals, for example by cooperating with the mmWave test module 508. The processor is configured to determine a channel estimate for an OTA connection between the communication device 500 and the UE, for example by cooperating with the mmWave test module 508 and the OTA channel equalizer module 509. The transceiver 510 is configured to generate a test signal using pre-compensation based on the channel estimate of the OTA connection, for example by cooperating with the mmWave test module 508 and the OTA channel equalizer module 509.

[0070] In one aspect, the communications apparatus 500 may include multiple transceivers 510 implementing different RATs (e.g., NR and LTE). In one aspect, the communications apparatus 500 may include a single transceiver 510 implementing multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 510 may include various components, where different combinations of components may implement different RATs.

[0071] FIG. 6 is a signaling diagram of a mmWave wireless communication device testing method 600 according to some aspects of the disclosure. The method 600 may be employed by the test system 300 to test a wireless communication device operating at mmWave frequencies. Specifically, the method 600 may be implemented between a test equipment 605 and a UE 615. The test equipment 605 may be similar to the BB test equipment 350, the RF test equipment 360, and / or the communication apparatus 500. The UE 615 may be similar to the UE 115, 315, and / or 400. The UE 615 may be disposed in an OTA test chamber similar to the OTA chamber 370. The steps of the method 600 may be performed by computing devices (e.g., processors, processing circuits, and / or other suitable components) of the test equipment 605 and the UE 615. As illustrated, the method 600 includes several enumerated steps, although embodiments of the method 600 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the recited steps may be omitted or performed in a different order.

[0072] At a high level, the test equipment 605 may transmit a reference signal to the UE 615. The UE 615 may report channel information based on the reference signal. The test equipment 605 may perform operations similar to a BS (e.g., BS 105). For example, the test equipment 605 may transmit SSB and / or CSI-RS to the UE 615, which may serve as a reference signal for channel measurements at the UE 615. The test equipment 605 may determine a channel response of the OTA connection (e.g., OTA channel 380) based on the reported channel information and pre-equalize or pre-compensate the test signal with an inverse response of the OTA channel estimate before transmitting the test signal to the UE 615.

[0073] In step 610, the test equipment 605 transmits an SSB to the UE 615. As described above, the SSB may include a PSS, an SSS, and / or a PBCH signal. In some aspects, the SSS may be used by the UE 615 for channel measurements. The test equipment 605 may transmit the SSB periodically. For example, the test equipment 605 may utilize a component, such as the transceiver 510, to transmit the SSB according to a certain periodicity.

[0074] In step 620, the test equipment 605 transmits the CSI-RS to the UE 615. The test equipment 605 may transmit the CSI-RS periodically. For example, the test equipment 605 may utilize a component such as the transceiver 510 to transmit the CSI-RS according to a certain periodicity. In some aspects, the test equipment 605 may transmit the SSS or SSB less frequently than the CSI-RS. In other words, the SSB or SSS has a lower periodicity than the CSI-RS. In addition, the SSB may occupy a smaller frequency bandwidth than the CSI-RS. For example, the SSB or SSS may occupy about 20 RBs (e.g., RB210) in a 15 kHz subcarrier spacing, while the CSI-RS may occupy the entire channel bandwidth or BWP used for communication between the test equipment 605 and the UE 615. In other words, the SSS or SSB may have a lower time density and / or frequency density than the CSI-RS. In this manner, the CSI-RS may enable more accurate channel measurements.

[0075] In step 630, upon receiving the SSB and CSI-RS, the UE 615 may determine channel state information based on the received SSB and CSI-RS. In this regard, the UE 615 may determine received signal power and / or relative phase information at an antenna element (e.g., antenna 416) at the UE 615 based on a synchronization signal in the SSB and / or CSI-RS. For example, the UE 615 may utilize components such as the processor 402, the channel measurement and reporting module 408, and the transceiver 410 to receive a signal carrying an SSB, receive a signal carrying a CSI-RS, determine a received signal power of the SSB, determine a received signal power of the CSI-RS, and determine a relative phase between signals received from a first antenna element and a second antenna element at the UE 615.

[0076] In some aspects, the UE 615 may determine the RSRPB and / or RSARP from a synchronization signal (e.g., SSS) in the SSB and / or CSI-RS. The RSRPB may refer to the received signal power per branch. For example, mmWave transmission may have two polarizations. The two polarizations may be orthogonal to each other. However, in practice, there may be leakage between the two polarizations. The UE 615 may calculate the received signal power of the SSS in one polarization and another received signal power of the SSS in another polarization. Similarly, the UE 615 may calculate the received signal power of the CSI-RS in one polarization and another received signal power of the CSI-RS in another polarization. The RSARP may refer to the phase difference between a reference antenna port and another antenna port at the UE 615. For example, the UE 615 may receive the SSS at antenna port 0 and antenna port 1. In some instances, the antenna port 0 and antenna port 1 may each correspond to one of the polarizations. The UE 615 may determine a phase difference between the SSS received on antenna port 0 and the SSS received on antenna port 1. Similarly, the UE 615 may receive CSI-RS on antenna port 0 and antenna port 1 and determine a phase difference between the CSI-RS received on antenna port 0 and the CSI-RS received on antenna port 1.

[0077] At step 640, the UE 615 transmits a channel report to the test equipment 605 based on the channel measurements. In some instances, the channel report may include an SSS-based determined RSRPB, an SSS-based determined RSARP, a CSI-RS-based determined RSRPB, a CSI-RS-based determined RSARP, or any combination thereof. For example, the UE 615 may utilize components such as the processor 402, the channel measurement and reporting module 408, and / or the transceiver 410 to transmit the channel report.

[0078] Upon receiving the channel report, in step 650, the test equipment 605 may determine a channel estimate for the OTA connection based on the received channel report. In this regard, the test equipment 605 may construct a channel matrix representing the OTA channel from the amplitude information determined from the received RSRPB and the phase information determined from the received RSARP.

[0079] With reference to the system 300 of FIG. 3 and equation (1) discussed above, the test equipment 605 derives the OTA channel matrix H from the received RSRPB and RSARP. undesired As an example, the test equipment 605 may have two transmit antennas (e.g., a first transmit antenna Tx0 and a second transmit antenna Tx1), and the UE 615 may have two receive antennas (e.g., a first receive antenna Rx0 and a second receive antenna Rx1). The test equipment 605 may transmit a reference signal using a first polarization via the first transmit antenna Tx0 and a second polarization via the second transmit antenna Tx1. For each polarization, the UE 615 may calculate the received signal power of the reference signal at the first receive antenna Rx0 and the received signal power of the reference signal at the second receive antenna Rx1. In this way, with two polarizations, the UE 615 may calculate and report four RSRPBs. For example, the four RSRPBs may include received signal power measured at a transmission based on UE antenna Rx0 from test equipment antenna Tx0 (denoted as Receive Tx0Rx0), received signal power measured at a transmission based on UE antenna Rx1 from test equipment antenna Tx0 (denoted as Receive Tx0Rx1), received signal power measured at a transmission based on UE antenna Rx0 from test equipment antenna Tx1 (denoted as Receive Tx1Rx0), and received signal power measured at a transmission based on UE antenna Rx1 from test equipment antenna Tx1 (denoted as Receive Tx1Rx1). The test equipment 605 may generate H based on the RSRPBs. undesiredSimilarly, for each polarization, the UE 615 may calculate the relative phase between the first and second receive antennas. In this way, with two polarizations, the UE 615 may calculate and report two RSARPs. For example, the RSARPs may include the relative phase between Tx0Rx0 and Tx0Rx1 and the relative phase between Tx1Rx0 and Tx1Rx1. The test equipment 605 may calculate the H Chamber In some instances, the test equipment 605 may construct a phase portion of the OTA channel estimate H based on the reported RSRPB and / or RSARP of the UE 615 as described above. undesired To construct the above, components such as a processor 502, an mmWave test module 508, an OTA channel equalizer module 509, and a transceiver 510 may be utilized.

[0080] In step 660, the OTA channel response or H undesired After determining H, the test equipment 605 undesired For example, the test equipment 605 may apply a zero-forcing (ZF) technique to determine a pseudo channel equalizer matrix as represented below:

[0081]

number

[0082] Where:

[0083]

number

[0084] represents the pseudo-channel equalizer matrix,

[0085]

number

[0086] Hundesired In some instances, the test equipment 605 may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to determine the OTA channel equalizer as shown in equation (2).

[0087] In step 670, the test equipment 605 may perform mmWave testing on the UE 615 by generating test signals using OTA channel pre-equalization as follows:

[0088]

number

[0089] where Y′ represents the signal received at the UE 615 after pre-equalization. As can be seen from equation (3), the UE 615 receives the desired channel H desired With and without OTA channels H undesired For example, the test equipment 605 may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to generate a test signal using OTA channel equalization as shown in equation (3).

[0090] The UE 615 may then determine a test result based on the test signal. The UE 615 may report the test result to the test equipment 605. Alternatively, the test equipment 605 may query the UE 615 for the test result.

[0091] In some aspects, steps 630-660 (illustrated by the dotted boxes) may be repeated, for example, at a period longer than the repetition period of the SSB transmission (e.g., a period of T) and / or the repetition period of the CSI-RS. In other words, the UE 615 may transmit an updated RSRPB and / or RSARP based on another reception of the SSS and / or CSI-RS, and the test equipment 605 may update the equalizer 616 based on the updated RSRPB and / or RSARP.

[0092]

number

[0093] may be recalculated or updated.

[0094] In some aspects, steps 630-660 may be repeated when the relative orientation between the test equipment 605 and the UE 615 changes. For example, the UE 615 may be repositioned in the OTA chamber such that transmission to and / or reception from the test equipment 605 changes to a different angle. As discussed above, the OTA channel may change based on the relative angle or orientation between the test equipment 605 and the UE 615. Thus, steps 630-660 may be repeated until the test equipment 605 retunes the equalizer for the updated channel before continuing with the test.

[0095]

number

[0096] can be updated.

[0097] Although the method 600 has been described in the context of testing a receiver of a UE 615, similar mechanisms may be applied to testing a receiver of the test equipment 605. For example, the test equipment 605 may apply a similar OTA channel equalizer to signals received from the UE to post-compensate for the OTA channel.

[0098] FIG. 7 is a flow diagram of a mmWave wireless communication device test method 700 according to some aspects of the disclosure. The steps of the method 700 may be performed by a computing device (e.g., a processor, processing circuitry, and / or other suitable components) of the apparatus, or other suitable means for performing the steps. For example, an apparatus, such as the communication apparatus 500, the test equipment 350 and / or 615, may utilize one or more components, such as the processor 502, the memory 504, the OTA channel equalizer module 509, the transceiver 510, the modem 512, and one or more antennas 516, to perform the steps of the method 700. The method 700 may employ a mechanism similar to that of the method 600 described above with respect to FIG. 6. As shown, the method 700 includes several enumerated steps, although aspects of the method 700 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0099] At block 710, the apparatus transmits one or more reference signals to wireless communication devices located within the OTA space. The wireless communication devices may correspond to UEs similar to the UEs 115, 315, and / or 615. For example, the apparatus may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to transmit the one or more reference signals to wireless communication devices located within the OTA space.

[0100] At block 720, the apparatus receives channel state information from a wireless communication device in response to the one or more reference signals. For example, the apparatus may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to receive channel state information from the wireless communication device in response to the one or more reference signals.

[0101] In block 730, the device calculates an OTA spatial channel estimate (e.g., H undesired For example, the device may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to determine a channel estimate in the OTA space based on the received channel state information.

[0102] At block 740, the apparatus transmits a reference channel (e.g., H desired ) and transmit a communication signal based on the OTA spatial channel estimate. For example, the apparatus may utilize components such as the processor 502, the mmWave test module 508, the OTA channel equalizer module 509, and the transceiver 510 to transmit a communication signal to a wireless communication device based on the reference channel and the OTA spatial channel estimate.

[0103] In some aspects, the channel state information includes at least one of a received signal power measurement based on a reference polarization or relative phase information between two antenna elements at the wireless communication device. In some aspects, the channel state information includes RSRPB, RSARP, or any combination thereof.

[0104] In some aspects, the one or more reference signals include a synchronization signal (e.g., SSS), a CSI-RS, or any combination thereof. In some aspects, the one or more reference signals include a CSI-RS and the channel state information includes at least one of an RSRPB or an RSARP measured from the CSI-RS. In some aspects, the device transmits the one or more reference signals in the mmWave band.

[0105] In some aspects, the apparatus further determines a ZF equalizer based on the OTA spatial channel estimate, eg, as shown in equation (2) above.

[0106] In some aspects, the OTA space includes an OTA test chamber similar to OTA chamber 370, and the channel state information includes channel characteristics associated with the OTA chamber and a front end of a wireless communication device (e.g., RF unit 414).

[0107] Information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0108] The various example blocks and modules described in connection with the present disclosure herein may be implemented or performed using a general purpose processor, a 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 alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0109] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored on or transmitted over a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of this 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, hardwiring, or any combination thereof. Features implementing the functions may also be physically located in various locations, including being distributed such that portions of the functions are implemented in different physical locations. Also, as used herein, including within the claims, "or" used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such as, 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).

[0110] As those skilled in the art will now appreciate, and depending on the particular application at hand, many modifications, substitutions and variations may be made in and to the materials, apparatus, configuration and methods of use of the devices of the present disclosure without departing from the spirit and scope of the present disclosure. In light of this, the specific embodiments shown and described herein are merely by way of example of some of them, and the scope of the present disclosure should not be limited to the scope of such specific embodiments, but rather should be fully equivalent to the scope of the following appended claims and their functional equivalents. [Explanation of symbols]

[0111] 100 Wireless communication network, network, wireless network 105 Base station (BS), BS 105a BS 105b BS 105c BS 105d BS, Macro BS 105e BS, Macro BS 105f BS, Small Cell BS 115 UE 115a UE 115b UE 115c UE 115d UE 115e UE 115f UE 115g UE 115h UE 115i UE 115j UE 115k UE 200 Radio Frame Structure 201 Radio Frame 202 Slots 204 Subcarrier 206 Symbols 208 Mini Slots 210 Resource Blocks (RB), RB 212 Resource Element (RE) 300 mmWave wireless communication device test system, test system, system 315 UE 330 Test Platform 332 Channel parameters 334 Noise parameters 336 RF parameters 340 Test Data Source 342 Test Vectors, Time Domain Test Signals, Test Signals 350 Baseband (BB) Test Equipment, BB Test Equipment, Test Equipment 352 BB signal 360 RF Test Equipment 362 RF signal, RF test signal, received signal 370 OTA chamber 380 OTA channels 400UE 402 processor 404 Memory 406 Command 408 Channel Measurement and Reporting Module 409 Test Measurement Module 410 Transceiver 412 Modem Subsystem 414 Radio Frequency (RF) Unit, RF Unit 416 Antenna 500 Communication Equipment 502 processor 504 Memory 506 Command 508 mmWave Test Module 509 OTA Channel Equalization Module, OTA Channel Equalizer Module 510 Transceiver 512 Modem Subsystem, Modem 514 RF unit 516 Antenna 600 mmWave wireless communication device testing method, method 605 Test Equipment 615 UE, Test Equipment 700 mmWave wireless communication device testing method, method

Claims

1. 1. A method of wireless communication, comprising: transmitting, by a communication device, one or more reference signals including at least a channel state information reference signal (CSI-RS) to a wireless communication device located in an over-the-air (OTA) space; receiving, by the communications apparatus, CSI from the wireless communications device in response to the one or more reference signals, the CSI including reference signal received power per branch (RSRPB) reports containing received signal power measurements and reference signal antenna relative phase (RSARP) reports containing relative phase information between two antenna elements at the wireless communications device, the received signal power measurements being based on a reference polarization; determining, by the communication device, a channel estimate in the OTA space by multiplying a value obtained by subtracting an artificial noise added to the communication device from the received CSI by an inverse vector of a test signal, an inverse matrix of a precoding matrix applied by the communication device, and an inverse matrix of a matrix indicating a baseband transfer characteristic specific to the communication device; transmitting, by the communication apparatus, a communication signal to the wireless communication device based on the baseband transfer characteristic and the channel estimate in the OTA space; Equipped method.

2. The transmitting step includes: transmitting, by the communication apparatus, a synchronization signal including a secondary synchronization signal (SSS) to the wireless communication device; The transmission frequency of the CSI-RS is higher than the transmission frequency of the SSS, or the frequency bandwidth used for transmitting the CSI-RS is larger than the frequency bandwidth used for transmitting the SSS. The method of claim 1.

3. The transmitting step includes: transmitting, by the communications apparatus, the one or more reference signals in a millimeter wave (mmWave) band to the wireless communications device.

2. The method of claim 1, comprising:

4. determining, by the communication device, a zero-forcing (ZF) equalizer based on the channel estimate in the OTA space; The method of claim 1 , further comprising:

5. generating, by the communication device, the communication signal based on a reference channel and the ZF equalizer; The method of claim 4 , further comprising:

6. 10. The method of claim 1, wherein the CSI includes channel characteristics associated with a front end of the wireless communication device.

7. A transceiver comprising: transmitting one or more reference signals, including at least a channel state information reference signal (CSI-RS), to wireless communication devices located in an over-the-air (OTA) space; receiving CSI from the wireless communication device in response to the one or more reference signals, the CSI including reference signal received power per branch (RSRPB) reports including received signal power measurements and reference signal antenna relative phase (RSARP) reports including relative phase information between two antenna elements at the wireless communication device, the received signal power measurements being based on a reference polarization; Transmitting a communication signal to the wireless communication device based on a baseband transfer characteristic specific to the communication device and the OTA spatial channel estimate. A transceiver configured as described above.

1. A processor comprising: The channel estimate in the OTA space is determined by multiplying the inverse vector of a test signal, the inverse matrix of a precoding matrix applied by the communication device, and the inverse matrix of a matrix indicating the baseband transfer characteristic by a value obtained by subtracting artificial noise added to the communication device from the received CSI. A processor configured as A communication device comprising:

8. the transceiver configured to transmit the one or more reference signals; configured to transmit a synchronization signal, including a secondary synchronization signal (SSS), to the wireless communication device; The transmission frequency of the CSI-RS is higher than the transmission frequency of the SSS, or the frequency bandwidth used for transmitting the CSI-RS is larger than the frequency bandwidth used for transmitting the SSS.

8. The communication device according to claim 7.

9. the transceiver configured to transmit the one or more reference signals; configured to transmit the one or more reference signals in a millimeter wave (mmWave) band to the wireless communication device.

8. The communication device according to claim 7.

10. The processor, and determining a zero-forcing (ZF) equalizer based on the channel estimate in the OTA space.

8. The communication device according to claim 7.

11. The processor, further configured to generate the communication signal based on a reference channel and the ZF equalizer.

11. The communication device according to claim 10.

12. 8. The communications apparatus of claim 7, wherein the CSI includes channel characteristics associated with a front end of the wireless communications device.

13. A non-transitory computer-readable storage medium embodied in a communications device and having program code recorded thereon, the program code comprising: code for causing the communications apparatus to transmit one or more reference signals, including at least a channel state information reference signal (CSI-RS), to wireless communications devices located in an over-the-air (OTA) space; and code for causing the communications apparatus to receive CSI from the wireless communication device in response to the one or more reference signals, the CSI including reference signal received power per branch (RSRPB) reports including received signal power measurements and reference signal antenna relative phase (RSARP) reports including relative phase information between two antenna elements at the wireless communication device, the received signal power measurements being based on a reference polarization; and code for causing the communication device to determine a channel estimate in the OTA space by multiplying a value obtained by subtracting an artificial noise added to the communication device from the received CSI by an inverse vector of a test signal, an inverse matrix of a precoding matrix applied by the communication device, and an inverse matrix of a matrix indicating a baseband transfer characteristic specific to the communication device; code for causing the communications apparatus to transmit a communication signal to the wireless communications device based on the baseband transfer characteristic and the channel estimate in the OTA space; A non-transitory computer-readable storage medium comprising:

14. the code for causing the communication device to transmit the one or more reference signals comprises: configured to transmit a synchronization signal, including a secondary synchronization signal (SSS), to the wireless communication device; The transmission frequency of the CSI-RS is higher than the transmission frequency of the SSS, or the frequency bandwidth used for transmitting the CSI-RS is larger than the frequency bandwidth used for transmitting the SSS.

14. The non-transitory computer-readable storage medium of claim 13.

15. the code for causing the communication device to transmit the one or more reference signals comprises: configured to transmit the one or more reference signals in a millimeter wave (mmWave) band to the wireless communication device.

14. The non-transitory computer-readable storage medium of claim 13.

16. code for causing the communication device to determine a zero-forcing (ZF) equalizer based on the channel estimate in the OTA space 14. The non-transitory computer-readable storage medium of claim 13, further comprising:

17. Code for causing the communication device to generate the communication signal based on a reference channel and the ZF equalizer 20. The non-transitory computer-readable storage medium of claim 16, further comprising:

18. 14. The non-transitory computer-readable storage medium of claim 13, wherein the CSI includes channel characteristics associated with a front end of the wireless communication device.

19. means for transmitting one or more reference signals including at least a channel state information reference signal (CSI-RS) to a wireless communication device located in an over-the-air (OTA) space, the CSI including a reference signal received power per branch (RSRPB) report including a received signal power measurement and a reference signal antenna relative phase (RSARP) report including relative phase information between two antenna elements at the wireless communication device, the received signal power measurement being based on a reference polarization; means for receiving CSI from the wireless communication device in response to the one or more reference signals; means for determining a channel estimate in the OTA space by multiplying the received CSI minus an artificial noise added to the communication device by an inverse vector of a test signal, an inverse matrix of a precoding matrix applied by the communication device, and an inverse matrix of a matrix indicating a baseband transfer characteristic specific to the communication device; means for transmitting, to the wireless communication device, a communication signal based on the baseband transfer characteristic and the channel estimate in the OTA space; A communication device comprising:

20. the means for transmitting the one or more reference signals further comprising: configured to transmit a synchronization signal, including a secondary synchronization signal (SSS), to the wireless communication device; The transmission frequency of the CSI-RS is higher than the transmission frequency of the SSS, or the frequency bandwidth used for transmitting the CSI-RS is larger than the frequency bandwidth used for transmitting the SSS.

20. The communication device of claim 19.

21. the means for transmitting the one or more reference signals further comprising: configured to transmit the one or more reference signals in a millimeter wave (mmWave) band to the wireless communication device.

20. The communication device of claim 19.

22. means for determining a zero-forcing (ZF) equalizer based on the channel estimate in the OTA space; The communication device of claim 19, further comprising:

23. Means for generating said communication signal based on a reference channel and said ZF equalizer. The communication device of claim 22, further comprising:

24. 20. The communications apparatus of claim 19, wherein the CSI includes channel characteristics associated with a front end of the wireless communications device.

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