Virtual cable calibration at device under test in OTA test settings

Abstract

An apparatus configured to: receive, from a test device, a first indication to estimate a channel matrix of a downlink channel; receiving at least one downlink reference signal from the test device; in response to the first indication, estimating a channel matrix based at least in part on the at least one downlink reference signal; receiving a second indication from the test device to determine a virtual cable calibration matrix; in response to the second indication, determining a virtual cable calibration matrix based at least in part on the estimated channel matrix; receiving, from the test device, a third indication to perform a virtual cable calibration on the at least one received baseband signal based at least in part on the virtual cable calibration matrix prior to demodulation; and performing a conformance test based at least in part on the virtual cable calibration.

Description

Technical Field

[0001] The exemplary and non-limiting embodiments generally relate to the testing of user equipment, and more specifically to over-the-air testing. Background Technology

[0002] In user equipment testing, it is known to perform airborne tests in an anechoic chamber. Summary of the Invention

[0003] The following description of the invention is for illustrative purposes only. This invention is not intended to limit the scope of the claims.

[0004] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: receive a first indication from a test device to estimate a channel matrix of a downlink channel; receive at least one downlink reference signal from the test device; estimate the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receive a second indication from the test device to determine a virtual cable calibration matrix; determine the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receive a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0005] According to one aspect, a method includes: receiving, via a device under test, a first indication of estimating a channel matrix of a downlink channel from a test device; receiving at least one downlink reference signal from the test device; estimating the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receiving, via the test device, a second indication of determining a virtual cable calibration matrix; determining the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receiving, via the test device, a third indication of performing virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix prior to demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0006] According to one aspect, an apparatus includes components for: receiving a first indication from a test device to estimate a channel matrix of a downlink channel; receiving at least one downlink reference signal from the test device; estimating the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receiving a second indication from the test device to determine a virtual cable calibration matrix; determining the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receiving a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0007] According to one aspect, a non-transitory computer-readable medium includes program instructions stored thereon for at least performing the following operations: causing a first indication to be received from a test device to estimate a channel matrix of a downlink channel; causing a first indication to be received from the test device to estimate at least one downlink reference signal; in response to the first indication, estimating the channel matrix at least in part based on the at least one downlink reference signal; causing a second indication to be received from the test device to determine a virtual cable calibration matrix; in response to the second indication, determining the virtual cable calibration matrix at least in part based on the estimated channel matrix; causing a third indication to be received from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0008] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: send a first indication to a user equipment (UE) to estimate a channel matrix of a downlink channel; send at least one downlink reference signal to the UE; send a second indication to the UE to calculate a virtual cable calibration matrix at least partially based on the estimated channel matrix; send a third indication to the UE to perform virtual cable calibration on at least one received baseband signal prior to demodulation, at least partially based on the virtual cable calibration matrix; receive an acknowledgment from the UE, wherein the acknowledgment is configured to acknowledge the virtual cable calibration; and perform a conformance test at least partially based on the virtual cable calibration.

[0009] According to one aspect, a method includes: sending a first indication to a user equipment via a test device of a channel matrix estimating a downlink channel; sending at least one downlink reference signal to the user equipment; sending a second indication to the user equipment of calculating a virtual cable calibration matrix based at least in part on the estimated channel matrix; sending a third indication to the user equipment of performing virtual cable calibration on at least one received baseband signal prior to demodulation, based at least in part on the virtual cable calibration matrix; and performing a conformance test based at least in part on the virtual cable calibration.

[0010] According to one aspect, an apparatus includes components for: transmitting to a user equipment a first indication of estimating a channel matrix of a downlink channel; transmitting to the user equipment at least one downlink reference signal; transmitting to the user equipment a second indication of calculating a virtual cable calibration matrix at least partially based on the estimated channel matrix; transmitting to the user equipment a third indication of performing virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least partially based on the virtual cable calibration.

[0011] According to one aspect, a non-transitory computer-readable medium includes program instructions stored thereon, the program instructions being configured to at least perform the following operations: cause a first indication to be sent to a user equipment to estimate a channel matrix of a downlink channel; cause at least one downlink reference signal to be sent to the user equipment; cause a second indication to be sent to the user equipment to calculate a virtual cable calibration matrix at least in part based on the estimated channel matrix; cause a third indication to be sent to the user equipment to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0012] The subject matter of the independent claims is provided in several respects. Other aspects are defined in the dependent claims. Attached Figure Description

[0013] The foregoing aspects and other features are explained in the following description taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1 This is a block diagram of a possible, non-limiting example system in which exemplary embodiments can be practiced;

[0015] Figure 2 It is a diagram illustrating the features described in this article;

[0016] Figure 3 It is a diagram illustrating the features described in this article;

[0017] Figure 4This is a flowchart illustrating the steps described in this article;

[0018] Figure 5 It is a diagram illustrating the features described in this article;

[0019] Figure 6 It is a flowchart illustrating the steps described in this article; and

[0020] Figure 7 This is a flowchart illustrating the steps described in this article. Detailed Implementation

[0021] The abbreviations that may appear in the instruction manual and / or drawings are defined as follows: 3GPP: Third Generation Partnership Project 5G: Fifth Generation 5GC: 5G Core Network AMF: Access and Mobility Management Functions AoA: Angle of Arrival cRAN: Cloud Radio Access Network CSI: Channel State Information CU: Central Unit DRX: Discontinuous Receiver DU: Distributed Unit DUT: Device Under Test eNB (or eNodeB): Evolved Node B (e.g., LTE base station) EN-DC: E-UTRA-NR Dual Connection en-gNB or En-gNB: A node that provides NR user plane and control plane protocol termination to the UE and acts as a secondary node in the EN-DC. E-UTRA: Evolved Universal Terrestrial Radio Access, i.e., LTE radio access technology. gNB (or gNodeB): A base station used for 5G / NR, that is, a node that provides NR user plane and control plane protocol termination to the UE and connects to the 5GC via the NG interface. IE: Information Elements I / F: Interface L1: Layer 1 LMMSE: Linear minimum mean square error LTE: Long Term Evolution MAC: Media Access Control MIMO: Multiple Input Multiple Output MME: Mobility Management Entity MMSE: Minimum Mean Square Error NAS: Non-Access Layer ng or NG: the new generation ng-eNB or NG-eNB: Next-generation eNB NR: New Radio N / W or NW: Network O-RAN: Open Radio Access Network OTA (Over-the-Air) PDCP: Packet Data Convergence Protocol PDSCH: Physical Downlink Shared Channel PHY: Physical Layer RAN: Radio Access Network RF: Radio frequency RLC: Radio Link Control RRC: Radio Resource Control RRH: Remote Radio Header RRM: Radio Resource Management RS: Reference signal RSRP: Reference Signal Received Power RSRP-B: Reference Signal Received Power per Branch RU: Radio Unit Rx: Receiver SDAP: Service Data Adaptation Protocol SGW: Service Gateway SMF: Session Management Function SS: System Simulator TE: Test equipment TRP: Transmitter / Receiver Point Tx: Transmitter UAI: User Equipment Assistance Information UE: User Equipment (e.g., wireless equipment, typically mobile equipment) UPF: User Plane Functionality VCC: Virtual Cable Calibration VNR: Virtualized Network Function

[0022] Turn Figure 1 The figure illustrates a block diagram of one possible, non-limiting example in which the example can be practiced. User equipment (UE) 110, radio access network (RAN) node 170, and network elements(s) 190 are illustrated. Figure 1In the example, User Equipment (UE) 110 wirelessly communicates with Wireless Network 100. The UE is a wireless device that can access Wireless Network 100. UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected via one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optic cable, or other optical communication device. "Circuit" may include dedicated hardware or hardware associated with software executable thereon. One or more transceivers 130 are connected to one or more antennas 128. One or more memories 125 include computer program code 123. UE 110 includes component 140, including one or both of portions 140-1 and / or 140-2, which may be implemented in various ways. Component 140 may be implemented in hardware as component 140-1, such as as part of one or more processors 120. Component 140-1 may also be implemented as an integrated circuit or through other hardware such as a programmable gate array. In another example, component 140 may be implemented as component 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, one or more memories 125 and computer program code 123 may be configured, together with one or more processors 120, to cause user equipment 110 to perform one or more operations as described herein. UE 110 communicates with RAN node 170 via radio link 111.

[0023] In this example, RAN node 170 is a base station that provides access to wireless network 100 for wireless devices (such as UE 110). RAN node 170 can be, for example, a base station for 5G, also known as New Radio (NR). In 5G, RAN node 170 can be an NG-RAN node, which is defined as a gNB or ng-eNB. A gNB is a node that provides NR user plane and control plane protocol termination to the UE and is connected to a 5GC (such as, for example, multiple network elements 190) via an NG interface. An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to the UE and is connected to a 5GC via an NG interface. An NG-RAN node can include multiple gNBs, which can also include a central unit (CU) (gNB-CU) 196 and multiple distributed units (DUs) (gNB-DU), where DU 195 is shown. It should be noted that a DU can include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node that hosts the RRC, SDAP, and PDCP protocols of the gNB or the en-gNB, and controls the operation of one or more gNB-DUs. The gNB-CU terminates the F1 interface connected to the gNB-DU. The F1 interface is illustrated as reference numeral 198, although reference numeral 198 also illustrates links between remote elements and centralized elements of RAN node 170, such as the link between gNB-CU 196 and gNB-DU 195. The gNB-DU is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and its operation is partially controlled by the gNB-CU. One gNB-CU supports one or more cells. The gNB-DU terminates the F1 interface 198 connected to the gNB-CU. It should be noted that DU195 is considered to include transceiver 160, for example, as part of the RU; however, some examples in this regard could allow transceiver 160 to be part of a separate RU, for example, under the control of DU 195 and connected to DU 195. RAN node 170 could also be an eNB (evolved NodeB) base station for LTE (Long Term Evolution), or any other suitable base station, access point, access node, or node.

[0024] RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / WI / F) 161, and one or more transceivers 160 interconnected via one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. CU 196 may include processor(s) 152, memory 155, and network interface 161. It should be noted that DU 195 may also contain its own one or more memories and processor(s), and / or other hardware, but these are not shown.

[0025] RAN node 170 includes component 150, comprising one or both of portions 150-1 and / or 150-2, which can be implemented in various ways. Component 150 can be implemented in hardware as component 150-1, such as as part of one or more processors 152. Component 150-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, component 150 can be implemented as component 150-2, which is implemented as computer program code 153 and executed by one or more processors 152. For example, one or more memories 155 and computer program code 153 are configured, together with one or more processors 152, to cause RAN node 170 to perform one or more operations as described herein. It should be noted that the functionality of component 150 can be distributed, such as being distributed between DU 195 and CU 196, or implemented solely in DU 195.

[0026] One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more gNBs 170 may communicate using, for example, link 176. Link 176 may be wired, wireless, or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interfaces for other standards.

[0027] One or more buses 157 may be address, data, or control buses and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fiber or other optical communication equipment, wireless channels, etc. For example, one or more transceivers 160 may be implemented as a Remote Radio Header (RRH) 195 for LTE or a Distributed Unit (DU) 195 for a gNB implementation for 5G, wherein other elements of the RAN node 170 may be physically located in a different location from the RRH / DU, and one or more buses 157 may be partially implemented as, for example, fiber optic cables or other suitable network connections to connect other elements of the RAN node 170 (e.g., Central Unit (CU), gNB-CU) to the RRH / DU 195. Reference numeral 198 also indicates these suitable network links(s).

[0028] It should be noted that the description in this document indicates that a "cell" performs a function; however, it should be clear that the equipment forming the cell will perform this function. Cells constitute part of a base station. That is, each base station can have multiple cells. For example, for a single carrier frequency and associated bandwidth, there can be three cells, each covering one-third of a 360-degree area, making the coverage area of ​​a single base station approximately elliptical or circular. Furthermore, each cell can correspond to a single carrier, and a base station can use multiple carriers. So if there are three 120-degree cells per carrier and two carriers, the base station has a total of six cells.

[0029] Wireless network 100 may include one or more network elements 190, which may include core network functions and provide connectivity to other networks (such as telephone networks and / or data communication networks (e.g., the Internet)) via one or more links 181. Such core network functions for 5G may include access and mobility management functions (AMF) and / or multiple user plane functions (UPF) and / or multiple session management functions (SMF). Such core network functions for LTE may include MME (Mobility Management Entity) / SGW (Serving Gateway) functions. These are merely illustrative functions that may be supported by network elements 190, and it should be noted that both 5G and LTE functions may be supported. RAN node 170 is coupled to network element 190 via link 131. Link 131 may be implemented as, for example, an NG interface for 5G, or an S1 interface for LTE, or other suitable interfaces for other standards. Network element 190 includes one or more processors 175 interconnected via one or more buses 185, one or more memories 171, and one or more network interfaces (N / WI / F) 180. The one or more memories 171 include computer program code 173. The one or more memories 171 and computer program code 173 are configured, together with the one or more processors 175, to cause network element 190 to perform one or more operations.

[0030] Wireless network 100 can implement network virtualization, which is the process of combining hardware and software network resources and network functions into a virtual network of a single software-based management entity. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is classified as external network virtualization or internal network virtualization. External network virtualization combines many networks or network parts into virtual units, while internal network virtualization provides network-like functionality to software containers on a single system. For example, a network can be deployed in a telecommunications cloud, where Virtualized Network Functions (VNFs) run on, for example, data center servers. For example, network core functions and / or (multiple) radio access networks (e.g., CloudRAN, O-RAN, edge cloud) can be virtualized. It should be noted that the virtualized entities resulting from network virtualization are still implemented to some extent using hardware such as processors 152 or 175 and memories 155 and 171, and such virtualized entities also produce technical effects.

[0031] It should also be noted that the operation of the example embodiments of this disclosure can be performed by multiple cooperating devices (e.g., cRAN).

[0032] Computer-readable storage devices 125, 155, and 171 can be of any type suitable for the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic storage devices and systems, optical storage devices and systems, fixed storage, and removable storage. Computer-readable storage devices 125, 155, and 171 can be components for performing storage functions. Processors 120, 152, and 175 can be of any type suitable for the local technical environment and, as a non-limiting example, can include one or more of the following: general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor architectures. Processors 120, 152, and 175 can be components for performing functions such as controlling UE 110, RAN node 170, and other functions described herein.

[0033] Typically, various example embodiments of user equipment 110 may include, but are not limited to, cellular phones with wireless communication capabilities (such as smartphones, tablets, personal digital assistants (PDAs)), portable computers with wireless communication capabilities, image capture devices with wireless communication capabilities (such as digital cameras), gaming devices with wireless communication capabilities, music storage and playback devices with wireless communication capabilities, internet devices that allow wireless internet access and browsing, tablets with wireless communication capabilities, and portable units or terminals that include a combination of such functions.

[0034] Therefore, having introduced a suitable but non-limiting technical background for practicing exemplary embodiments of this disclosure, the exemplary embodiments will now be described in more detail.

[0035] The features described in this article generally relate to conducted testing. One of the biggest challenges for test and measurement equipment / device manufacturers is achieving standardized evaluation and verification methods for UEs under repeatable and realistic conditions, methods that are also reliable in large-scale production. For LTE and 5G NR FR1 testing, conducted testing methods are standard for multiple-input multiple-output (MIMO) devices. During testing, the antenna of the device under test (DUT) is disconnected from the antenna port, and the DUT is directly connected to the test system using a coaxial cable.

[0036] Traditional conduction testing systems for FR1 requirements Figure 2 The diagram shows each UE antenna port (240, 250) connected to the test system (210) via a 50-ohm cable. Figure 2In the example, DUT 230 is connected to channel simulator 220 via a coaxial cable (instead of directly connecting to system simulator (SS) or test equipment (TE) 210), and channel simulator 220 is connected to SS / TE 210 via a cable. SS / TE models the transmit-receive point (TRP), while the channel (fading) simulator models a real-world wireless channel. It can be noted that... Figure 2 The examples are not limiting; for example, the channel emulator 220 can be implemented inside the SS / TE 210.

[0037] In this disclosure, the terms UE and DUT are used interchangeably.

[0038] In this disclosure, TRP can refer to a receiving point, a transmitting point, or both.

[0039] Figure 2 The illustration shows an example of a 4×4 system with two H / V polarized antenna panels at the device under test (DUT) (230). For a conventional conducted test system, the received signal can be modeled as: (1)

[0040] in x This is a transmitted signal from the Transmitter-Receiver Point (TRP) (here, a system simulator or test device) (220). H L It is a channel matrix simulated by a channel simulator (e.g., 2×2, 4×4, etc.), and y This is the received signal at the DUT.

[0041] Since the DUT antenna ports (240, 250) are connected to the channel simulator 220 and / or the test system (210) via cables, there is no crosstalk in the channel of the test chamber, and therefore, the inherent channel matrix of the test chamber (for an ideal scenario) can be modeled as a 4th-order identity matrix, for example:

[0042] This assumes that the cables have perfect unity gain (i.e., no crosstalk between cables or connectors, and no loss). Therefore, for compliance testing purposes, the crosstalk generated by the wireless channel used for the DUT deployed in the field is measured in the channel simulator H. L It is modeled in (220).

[0043] In the context of 3GPP (3rd Generation Partnership Project), conformance testing refers to a standardized set of tests and procedures designed to ensure that telecommunications equipment and devices, such as mobile phones and network infrastructure, conform to the technical specifications and standards defined by 3GPP. These tests are necessary to ensure interoperability and compatibility between products from different manufacturers within the 3GPP ecosystem.

[0044] The features described in this article generally relate to over-the-air (OTA) testing, such as multi-TRP / multi-probe radiation (OTA) test systems. Over-the-air (OTA) testing is a technique used to evaluate the performance and reliability of cordless devices in the real world. Testers use a test chamber with an open vacuum space to represent real-world scenarios. It undergoes a series of tests to determine how the device will respond to various systems. By analyzing the entire signal path and antenna functionality, OTA antenna testing helps confirm that the developed or selected device will function as expected. For testing UEs in the FR2 band, conducted testing methods are impractical because the numerous integrated antennas on the UE used for spatial multiplexing and beamforming require OTA testing without cable connections.

[0045] 5G New Radio (NR) is the first standard used to utilize millimeter-wave frequency bands for higher data transmission rates. The highly integrated front-end and array antennas require advanced over-the-air (OTA) testing methodologies and new RF test metrics for evaluating current and future mobile communications. Such test metrics include Virtual Cable Calibration (VCC), which is mandatory or preferred for reproducible and reliable OTA throughput testing. For performance testing simulating fading, such as Radio Resource Management (RRM) compliance and demodulation testing, the VCC method is crucial for evaluating defined antenna relevance and minimal crosstalk from the OTA link.

[0046] An example of a multi-TRP multi-Rx demodulation OTA test system is shown in Figure 3 The diagram shows a UE (350) placed within an anechoic chamber (330), and a test system (including an SS / TE 310 and a channel simulator 320, which may be separate or components of each other) connected to two (or more) dual-polarized probes (340) at different locations within the chamber. In this configuration, the received signal can be modeled as: (2)

[0047] in x This is a signal sent from TRP (here, a system simulator or test device). H L It is the same channel matrix (e.g., 2×2, 4×4, etc.) as that in a conventional conducted test system simulated by a channel simulator (320). HOTA Including OTA chambers and DUTs (including spatial filters), and y This is the received signal at the DUT.

[0048] This type of OTA test chamber ( H OTA The inherent channel matrix between the probe antenna and the baseband receiver branch of the DUT is more difficult to characterize. However, it is clear that different crosstalk factors need to be considered, and these can be broadly categorized into inter-polarity crosstalk factors and intra-polarity crosstalk factors:

[0049] OTA testing introduces challenges. Transmitted signals propagating in the wireless channel (i.e., the OTA channel in the test chamber) are distorted by other signals and noise. To achieve reproducible conditions similar to those defined in conducted testing, the effects of the OTA channel in the test chamber must be eliminated. One approach to this problem is to calculate the unknown transmission matrix A by considering the complete OTA environment, including the characteristics of both the transmitter and receiver antennas. This method is complex and, in most cases, impossible: UE manufacturers do not need to provide detailed information about their antenna characteristics, including the phase information required to apply this method.

[0050] For conformance testing, it is necessary to accurately simulate the behavior of a real-world wireless channel within an anechoic chamber (between the base station and the UE) in a controlled manner. Currently, this is being addressed in FR1 conducted mode testing (see...). Figure 2 This is achieved by using a channel fading simulator, which generates the desired wireless channel matrix during compliance testing. H L However, for FR2, only over-the-air (OTA) testing is permitted, and therefore requires the adoption of... Figure 3 The test settings are shown.

[0051] In OTA testing, the problem lies in the existence of a wireless channel between the transmit probe (340) of the test equipment installed within the anechoic test chamber (330) and the antenna panel / module (360) of the DUT. This channel does not exist in a real-world environment (i.e., it only exists during OTA compliance testing), and therefore its impact on the received signal (e.g., crosstalk / interference) is undesirable and may lead to incorrect test results. Therefore, mitigating the impact of the OTA channel in the anechoic chamber is necessary to achieve correct test results. This can be achieved by implementing wireless / virtual cable calibration at the test equipment.

[0052] The Rel-18 multi-Rx work item processing handles up to four DL layers received at the UE from two different arrival directions / angles. During conformance testing, these four DL layers can be transmitted by four single-polarization probes, resulting in a 4×4 size OTA matrix for the anechoic chamber. Indian Provisional Patent Application No. 202341053907 (filed August 11, 2023) (the entire contents of which are incorporated herein by reference) proposes a process for sending an estimate of the OTA matrix coefficients of the anechoic chamber back to a test device so that the test device can implement a Virtual Cable Calibration (VCC) matrix on its side. However, this method is not optimal for more advanced UEs supporting multi-TRP, multi-panel DL reception (e.g., more than two TRPs and two UE panels) or more MIMO layers, because the size of the OTA matrix / MIMO matrix increases with the number of TRPs and / or UE panels and / or layers. This increases the feedback overhead required to send the OTA matrix estimate to the test device for VCC implementation.

[0053] The alternative approach uses only the per-branch reference signal received power (RSRP-B) feedback parameter to derive the VCC matrix, which can be retrieved from the FR2 UE according to 3GPP standards. This enables quasi-conducted or "virtual cable" connections or "virtual cabling" in the FR2 radiated test environment. This approach lays the foundation for practical 5G UE performance testing, including maximum throughput and testing under various channel conditions such as fading. Channel equalization is also mandatory for conformance testing under fading conditions (which is required for RRM testing).

[0054] Current schemes for finding the virtual cable calibration matrix based on the reference signal received power per branch (RSRP-B) can take hours, which is too long to find enough DUT / probe locations for OTA compliance testing under various angles of arrival (AoA) conditions. Furthermore, for advanced UEs supporting multi-TRP, multi-panel DL reception or numerous MIMO layers (e.g., for far more than 2 TRPs and 2 UE panels; relevant to future 3GPP releases and / or 6G), the method proposed in Indian Provisional Patent Application No. 202341053907 may not be optimal because it would increase the feedback overhead required to send the OTA matrix estimate to the test equipment for VCC implementation (due to the increased size of the OTA matrix / MIMO matrix).

[0055] The goal is to find an optimal, faster, and easier method to implement a virtual calibration matrix to mitigate the effects of OTA matrices and potentially achieve greater isolation.

[0056] In the example embodiment, the DUT can use downlink training / reference symbols to estimate the OTA matrix of the anechoic chamber. HOTA .

[0057] In an example embodiment, the DUT can be based on the estimated matrix. To calculate the VCC matrix H VCC . It can be defined as H OTA The VCC matrix can also be estimated based on the received reference signal.

[0058] In the example embodiment, the DUT may have the computed VCC matrix at the DUT location. H VCC For example, it will be used for VCC at a later point in time during OTA conformance testing.

[0059] In an example embodiment, the DUT may apply the VCC matrix to the received baseband signal (e.g., multiple information signal vectors received on the Physical Downlink Shared Channel (PDSCH)) before the demodulation operation.

[0060] In an example embodiment, the test equipment (TE) or system simulator (SS) can provide the DUT with the configuration of downlink training / reference symbols so that the DUT can estimate the downlink training / reference symbols before the actual conformance test begins. H OTA .

[0061] In an example embodiment, the test equipment or system simulator can instruct the DUT to adjust the estimated matrix using new signaling. To calculate the VCC matrix ( H VCC ), and store the computed VCC matrix at the DUT (Device Under Test). H VCC For example, it will be used for VCC at a later point in time during OTA conformance testing.

[0062] In an example embodiment, the test equipment or system simulator may instruct the DUT to apply the VCC matrix to the received baseband signal via new signaling (e.g., before demodulation).

[0063] Now for reference Figure 4 The diagram illustrates the messages that can be exchanged between the TE / SS and the high-level message flow used to implement the expected DUT actions at the DUT to achieve VCC.

[0064] At point 405, the UE-side VCC calibration process can be initiated by the TE / SS and DUT. At point 410, the TE / SS can send the estimated H to the DUT. OTARequired configuration. The test equipment can be configured to estimate H by utilizing the required configuration parameters provided by RRC messages (e.g., RRC reconfiguration messages). OTA Furthermore, the test equipment can also configure / set its parameters for the same purpose, for example, by using the "channel simulator" matrix (see...). Figure 3 Set it to an identity matrix of appropriate order.

[0065] At position 415, TE / SS can send H to DUT. OTA The estimated trigger can send a reference signal. The test equipment can trigger H via newly defined RRC signaling or via dedicated non-access stratum (NAS) signaling for conformance testing (i.e., by defining a new RAN5 conformance test function for the same purpose). OTA Estimate and transmit the DL reference signal. The reference signal can typically be used to estimate the wireless channel matrix / coefficients and / or the VCC matrix.

[0066] At 420, the DUT can estimate H. OTA Matrix. Optionally, at 425, the DUT can send an acknowledgment or response to the TE / SS. The DUT can send a response message to the test equipment to acknowledge the completion of the estimation phase. This response can be sent explicitly in the UL, for example, via a "UE Assistance Information" message or a RAN5 conformance test response message. Alternatively, the response can be implicitly indicated to the test equipment, for example, by providing the test equipment with a Channel State Information (CSI) report, upon receiving the CSI report, the test equipment will infer H OTA It is estimated at the DUT.

[0067] The DUT can estimate the complete DL channel (which includes the combined effects of the channel simulator, connecting cables, and the OTA test chamber). However, the estimated channel may only correspond to the OTA test chamber portion of the DL channel (between the test probe and the DUT). This is because, during this estimation, the channel simulator is set to an identity matrix, and the cable is assumed to be perfect; therefore, the channel corresponding to the cable can also be modeled as an identity matrix. Thus, in this case, the combined DL channel may only correspond to the OTA channel portion between the test probe and the DUT (see, for example, [link to relevant documentation]). Figure 3 ).

[0068] onlyH OTA The value is estimated at the DUT and (optionally) notified to the test equipment. At 430, the TE / SS can send a signal to the DUT to use H. OTA The estimate is used to calculate and store the VCC matrix H. VCCThe TE / SS may optionally send the DUT an indication of the method to be used to calculate the VCC matrix (e.g., zero-forcing or linear minimum mean square error (LMMSE) or some other method), for example, in the case where more than one method is normalized to derive the VCC matrix at the DUT. These indications(s) can be communicated to the DUT via the new RRC signaling message / information element or via the new RAN5 conformance test function.

[0069] At position 435, the DUT can use H. OTA The estimate is used to calculate the VCC matrix H. VCC VCC matrix H VCC The indicated method can be used to determine the VCC matrix H. VCC It can be stored for later use. For example, the coefficients of the matrix can be stored.

[0070] Optionally, at 440, the DUT can send an acknowledgment or response to the TE / SS (e.g., via a "UE Assistance Information" message or a RAN5 conformance test response message). The acknowledgment or response can confirm the calculation and storage of the VCC matrix for future use.

[0071] At position 445, the TE / SS can send a signal to the DUT applying the VCC matrix H to the received DL signal at the DUT. VCC Instructions, such as those provided by new RRC signaling messages / information elements or by the new RAN5 conformance test function.

[0072] At 450, the DUT can multiply the received DL baseband symbol vector (before demodulation) by the VCC matrix H. VCC For example, if y is the received baseband symbol vector (before demodulation), then the symbol vector obtained after performing VCC at the DUT will be H. VCC y, where " " indicates matrix multiplication.

[0073] At point 455, the DUT can send an acknowledgment or response to the TE / SS, for example, via a "UE Assistance Information" message or a RAN5 conformance test response message. The acknowledgment or response confirms the implementation of VCC at the DUT, after which the TE can initiate the actual conformance test.

[0074] At point 460, the OTA consistency test can begin. At point 465, the OTA consistency test can end.

[0075] In an alternative example embodiment, H is triggered at the DUT. OTA The estimated indication (415), calculated / derived and stored H at the DUTVCC The instruction (430) and the instruction (445) to apply VCC at the DUT can both be communicated to the DUT in a single message, for example, (essentially) simultaneously or in parallel. Alternatively, the instruction can be compressed together. The technical effect of sending the instruction together can be to save message exchange time and / or reduce overall signaling overhead.

[0076] In an alternative example embodiment, H is calculated / derived and stored at the DUT. VCC The instruction (430) and the instruction (445) to apply VCC at the DUT can include the same instruction / signaling. In other words, a single instruction can be used to cause the DUT to derive the VCC matrix and apply it to VCC starting from time slot [x].

[0077] In an example embodiment, virtual cable calibration can be applied at the DUT for OTA compliance testing, for example... Figure 5 As shown. The DUT may include one or more panels (510, 520, 530) connected to the RF chain (540). The baseband (550) may include virtual cable calibration (560) at the DUT module, frame, or function, as well as demodulation and other processing modules, frames, or functions (570).

[0078] like Figure 5 As shown, before virtual cable calibration is performed at the DUT, the DUT may need to first estimate the DL channel, i.e., H OTA (For example, between the test probe and the UE antenna panel), then, for example, by using H OTA The VCC matrix is ​​calculated using the estimate, i.e., H VCC And stored in DUT H VCC For example, it will be used for VCC at a later point in time (e.g., just before the OTA conformance test is started).

[0079] In an additional example embodiment, the DUT may use a separate demodulator for each RF front-end or each panel. In this case, each front-end / panel / demodulator may require a VCC block. The steps according to the example embodiments of this disclosure can then be applied to each VCC block.

[0080] The technical advantage of the exemplary embodiments of this disclosure is that it can provide an optimal solution by implementing VCC at the DUT. The technical advantage of the exemplary embodiments of this disclosure is that it can provide a simple and fast method for implementing OTA compliance testing of virtual cable solutions. The technical advantage of the exemplary embodiments of this disclosure is that it eliminates the need for exhaustive search to obtain optimal weights.

[0081] The technical effects of the exemplary embodiments of this disclosure can be improved testing time and, consequently, improved testing costs.

[0082] The technical effect of the exemplary embodiments of this disclosure can be to eliminate the quantization error observed during the feedback process, since the OTA matrix coefficients are not fed back to the test equipment.

[0083] The technical effect of the exemplary embodiments of this disclosure can be to ensure easy debugging in the event of errors, such as... Figure 4 As the example shows, each instruction can only be sent to the DUT in the DL after the response to the previous instruction has been received at the TE.

[0084] The technical effect of the exemplary embodiments of this disclosure is that it can save signaling message exchange time, resources and energy in all alternative schemes where instructions are sent to the DUT in a single message in the DL.

[0085] Figure 6 The illustration shows the potential steps of example method 600. Example method 600 may include: receiving a first instruction 610 from a test device to estimate a channel matrix of a downlink channel; receiving at least one downlink reference signal 620 from the test device; estimating the channel matrix 630 at least partially based on the at least one downlink reference signal in response to the first instruction; receiving a second instruction 640 from the test device to determine a virtual cable calibration matrix; determining the virtual cable calibration matrix 650 at least partially based on the estimated channel matrix in response to the second instruction; receiving a third instruction 660 from the test device to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and performing a conformance test 670 at least partially based on the virtual cable calibration. Example method 600 may be performed, for example, by a UE, DUT, etc.

[0086] Figure 7 The illustration depicts the potential steps of example method 700. Example method 700 may include: sending a first indication 710 to a user equipment (UE) to estimate a channel matrix of a downlink channel; sending at least one downlink reference signal 720 to the UE; sending a second indication 730 to the UE for calculating a virtual cable calibration matrix at least partially based on the estimated channel matrix; sending a third indication 740 to the UE to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and performing a conformance test 750 at least partially based on the virtual cable calibration. Example method 700 may be performed, for example, via TE, SS, etc.

[0087] According to one example embodiment, an apparatus may include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: receive a first indication from a test device to estimate a channel matrix of a downlink channel; receive at least one downlink reference signal from the test device; estimate the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receive a second indication from the test device to determine a virtual cable calibration matrix; determine the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receive a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0088] The first indication of the estimated channel matrix can be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0089] The example device can also be configured to send confirmation to the test equipment that the channel matrix has been estimated.

[0090] The confirmation may be sent via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0091] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0092] The virtual cable calibration matrix can be determined, at least in part, based on the indicated method used to determine the virtual cable calibration matrix.

[0093] The second instruction may be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0094] The example device can also be configured to send confirmation to the test equipment that the virtual cable calibration matrix has been determined.

[0095] The third instruction may be received via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0096] The first, second, and third instructions can be received in parallel via the same message.

[0097] The first, second, and third instructions can be received as compressed messages.

[0098] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0099] The example device can also be configured to multiply at least one received baseband signal by a virtual cable calibration matrix before demodulation, in response to a third instruction.

[0100] The example apparatus can also be configured to receive from a test device a configuration for at least one downlink reference signal, wherein the channel matrix can be estimated at least in part based on the configuration.

[0101] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe in the test chamber and the device.

[0102] The example device can also be configured to send a response to the test equipment, wherein the response can be configured to acknowledge the virtual cable calibration.

[0103] According to one aspect, an example method may be provided, the example method comprising: receiving, via a device under test, a first indication of estimating a channel matrix of a downlink channel from a test device; receiving, via the test device, at least one downlink reference signal; estimating, at least partially based on the at least one downlink reference signal, in response to the first indication; receiving, via the test device, a second indication of determining a virtual cable calibration matrix; determining, at least partially based on the estimated channel matrix, in response to the second indication; receiving, via the test device, a third indication of performing virtual cable calibration on at least one received baseband signal, at least partially based on the virtual cable calibration matrix, prior to demodulation; and performing a conformance test, at least partially based on the virtual cable calibration.

[0104] The first indication of the estimated channel matrix can be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0105] Example methods may also include sending confirmation to the test device that the channel matrix has been estimated.

[0106] The confirmation may be sent via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0107] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0108] The virtual cable calibration matrix can be determined, at least in part, based on the indicated method used to determine the virtual cable calibration matrix.

[0109] The second instruction may be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0110] Example methods may also include sending confirmation to the test equipment that the virtual cable calibration matrix has been determined.

[0111] The third instruction may be received via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0112] The first, second, and third instructions can be received in parallel via the same message.

[0113] The first, second, and third instructions can be received as compressed messages.

[0114] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0115] The example method may also include: in response to a third instruction, multiplying at least one received baseband signal by a virtual cable calibration matrix before demodulation.

[0116] The example method may also include: receiving from a test device a configuration for at least one downlink reference signal, wherein the channel matrix may be estimated at least in part based on the configuration.

[0117] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe and the device under test in the test chamber.

[0118] Example methods may also include sending a response to the test device, wherein the response can be configured to acknowledge virtual cable calibration.

[0119] According to one example embodiment, an apparatus may include: circuitry configured to: receive a first indication from a test device to estimate a channel matrix of a downlink channel; circuitry configured to: receive at least one downlink reference signal from the test device; circuitry configured to: estimate the channel matrix at least partially based on the at least one downlink reference signal in response to the first indication; circuitry configured to: receive from the test device to determine a virtual cable calibration matrix; circuitry configured to: determine the virtual cable calibration matrix at least partially based on the estimated channel matrix in response to a second indication; circuitry configured to: receive from the test device a third indication to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and circuitry configured to: perform a conformance test at least partially based on the virtual cable calibration.

[0120] According to one example embodiment, an apparatus may include: a processing circuitry system; and a memory circuitry system including computer program code configured, together with the processing circuitry system, to enable the apparatus to: receive from a test device a first indication of estimating a channel matrix for a downlink channel; receive from the test device at least one downlink reference signal; estimate the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receive from the test device a second indication of determining a virtual cable calibration matrix; determine the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receive from the test device a third indication of performing virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0121] As used in this application, the term "circuit system" may refer to one or more or all of the following: (a) a hardware circuit implementation only (such as an implementation in an analog and / or digital circuit system only) and (b) a combination of hardware circuitry and software, such as (if applicable): (i) a combination of (multiple) analog and / or digital hardware circuitry with software / firmware, and (ii) any portion of (multiple) hardware processors (including (multiple) digital signal processors), software, and (multiple) memories having software, which work together to enable a device (such as a mobile phone or a server) to perform various functions; and (c) (multiple) hardware circuitry and / or (multiple) processors, such as (multiple) microprocessors or portions of (multiple) microprocessors, which require software (e.g., firmware) to operate, but may be absent when the software is not required to operate. This definition of circuit system applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term circuit system also covers implementations of hardware circuitry or processors (or multiple processors) only, or portions of hardware circuitry or processing and their accompanying software and / or firmware. The term "circuit system" also covers, for example and if applicable to certain claim elements, baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0122] According to one example embodiment, an apparatus may include components for: receiving a first indication from a test device to estimate a channel matrix of a downlink channel; receiving at least one downlink reference signal from the test device; estimating the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receiving a second indication from the test device to determine a virtual cable calibration matrix; determining the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receiving a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0123] The first indication of the estimated channel matrix can be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0124] This component can also be configured to send confirmation to the test equipment that the channel matrix has been estimated.

[0125] The confirmation may be sent via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0126] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0127] The virtual cable calibration matrix can be determined, at least in part, based on the indicated method used to determine the virtual cable calibration matrix.

[0128] The second instruction may be received via at least one of the following: radio resource control signaling, or non-access stratum signaling using the user equipment dedicated conformance test function.

[0129] This component can also be configured to: send confirmation to the test equipment that the virtual cable calibration matrix has been determined.

[0130] The third instruction may be received via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0131] The first, second, and third instructions can be received in parallel via the same message.

[0132] The first, second, and third instructions can be received as compressed messages.

[0133] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0134] The component can also be configured to: in response to a third instruction, multiply at least one received baseband signal by a virtual cable calibration matrix before demodulation.

[0135] The component can also be configured to: receive from the test equipment a configuration for at least one downlink reference signal, wherein the channel matrix can be estimated at least in part based on the configuration.

[0136] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe in the test chamber and the device.

[0137] The component can also be configured to send a response to the test equipment, wherein the response can be configured to confirm the virtual cable calibration.

[0138] Processors, memory, and / or example algorithms (which may be encoded as instructions, programs, or code) may be provided as example components for providing or causing the execution of operations.

[0139] According to one example embodiment, a non-transitory computer-readable medium includes instructions stored thereon that, when executed by at least one processor, cause the at least one processor to: receive a first indication from a test device to estimate a channel matrix of a downlink channel; receive at least one downlink reference signal from the test device; estimate the channel matrix at least in part based on the at least one downlink reference signal in response to the first indication; receive a second indication from the test device to determine a virtual cable calibration matrix; determine the virtual cable calibration matrix at least in part based on the estimated channel matrix in response to the second indication; receive a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0140] According to one example embodiment, a non-transitory computer-readable medium includes program instructions stored thereon for at least performing the following operations: causing a first indication to be received from a test device to estimate a channel matrix of a downlink channel; causing a first indication to be received from the test device to estimate at least one downlink reference signal; in response to the first indication, estimating the channel matrix at least in part based on the at least one downlink reference signal; causing a second indication to be received from the test device to determine a virtual cable calibration matrix; in response to the second indication, determining the virtual cable calibration matrix at least in part based on the estimated channel matrix; causing a third indication to be received from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0141] According to another example embodiment, a machine-readable non-transitory program storage device may be provided, the device tangibly embodying instructions executable by the machine for performing operations including: receiving a first indication from a test device to estimate a channel matrix of a downlink channel; receiving at least one downlink reference signal from the test device; estimating the channel matrix at least partially based on the at least one downlink reference signal in response to the first indication; receiving a second indication from the test device to determine a virtual cable calibration matrix; determining the virtual cable calibration matrix at least partially based on the estimated channel matrix in response to the second indication; receiving a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least partially based on the virtual cable calibration.

[0142] According to another example embodiment, a non-transitory computer-readable medium includes instructions that, when executed by a device, cause the device to perform at least the following operations: cause the device to receive a first indication from a test device to estimate a channel matrix of a downlink channel; cause the device to receive at least one downlink reference signal from the test device; in response to the first indication, estimate the channel matrix at least in part based on the at least one downlink reference signal; cause the device to receive a second indication from the test device to determine a virtual cable calibration matrix; in response to the second indication, determine the virtual cable calibration matrix at least in part based on the estimated channel matrix; cause the device to receive a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0143] A computer-implemented system includes: at least one processor and at least one non-transitory memory storing instructions that, when executed by the at least one processor, cause the system to at least: receive a first indication from a test device to estimate a channel matrix of a downlink channel; receive at least one downlink reference signal from the test device; estimate the channel matrix at least partially based on the at least one downlink reference signal in response to the first indication; receive a second indication from the test device to determine a virtual cable calibration matrix; determine the virtual cable calibration matrix at least partially based on the estimated channel matrix in response to the second indication; receive a third indication from the test device to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least partially based on the virtual cable calibration.

[0144] A computer-implemented system includes: components for receiving a first indication from a test device of an estimated channel matrix for a downlink channel; components for receiving at least one downlink reference signal from the test device; components for estimating the channel matrix at least partially based on the at least one downlink reference signal in response to the first indication; components for receiving a second indication from the test device of determining a virtual cable calibration matrix; components for determining the virtual cable calibration matrix at least partially based on the estimated channel matrix in response to the second indication; components for receiving a third indication from the test device of performing virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and components for performing a conformance test at least partially based on the virtual cable calibration.

[0145] According to one example embodiment, an apparatus may include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: send a first indication to a user equipment (UE) to estimate a channel matrix of a downlink channel; send at least one downlink reference signal to the UE; send a second indication to the UE to calculate a virtual cable calibration matrix at least in part based on the estimated channel matrix; send a third indication to the UE to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0146] The first indication of the estimated channel matrix can be transmitted via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0147] The example device can also be configured to receive confirmation from the user equipment that the channel matrix has been estimated.

[0148] The confirmation can be received via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0149] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0150] The second instruction may be sent via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0151] The example device can also be configured to receive confirmation from the user equipment that the virtual cable calibration matrix has been determined.

[0152] The third instruction may be sent via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0153] The first, second, and third instructions can be sent in parallel via the same message.

[0154] The first, second, and third instructions can be sent as compressed messages.

[0155] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0156] The example apparatus can also be configured to transmit a configuration for at least one downlink reference signal to a user equipment, wherein the channel matrix can be configured to be estimated at least in part based on the configuration.

[0157] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe and the user equipment in the test chamber.

[0158] The example device can also be configured to receive a response from a user equipment, wherein the response can be configured to acknowledge virtual cable calibration.

[0159] According to one aspect, an example method may be provided, comprising: sending a first indication to a user equipment via a test device of an estimated channel matrix of a downlink channel; sending at least one downlink reference signal to the user equipment; sending a second indication to the user equipment of calculating a virtual cable calibration matrix at least partially based on the estimated channel matrix; sending a third indication to the user equipment of performing virtual cable calibration on at least one received baseband signal prior to demodulation, at least partially based on the virtual cable calibration matrix; and performing a conformance test at least partially based on the virtual cable calibration.

[0160] The first indication of the estimated channel matrix can be transmitted via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0161] Example methods may also include: receiving confirmation from the user equipment that the channel matrix has been estimated.

[0162] The confirmation can be received via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0163] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0164] The second instruction may be sent via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0165] Example methods may also include: receiving confirmation from the user equipment that the virtual cable calibration matrix has been determined.

[0166] The third instruction may be sent via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0167] The first, second, and third instructions can be sent in parallel via the same message.

[0168] The first, second, and third instructions can be sent as compressed messages.

[0169] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0170] The example method may also include: sending a configuration to a user equipment for at least one downlink reference signal, wherein the channel matrix can be configured to be estimated at least in part based on the configuration.

[0171] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe and the user equipment in the test chamber.

[0172] Example methods may also include receiving a response from a user equipment, wherein the response can be configured to acknowledge virtual cable calibration.

[0173] According to one example embodiment, an apparatus may include: circuitry configured to: send a first indication to a user equipment via a test device a channel matrix estimating a downlink channel; circuitry configured to: send at least one downlink reference signal to the user equipment; circuitry configured to: send a second indication to the user equipment for calculating a virtual cable calibration matrix based at least in part on the estimated channel matrix; circuitry configured to: send a third indication to the user equipment for performing virtual cable calibration on at least one received baseband signal prior to demodulation, based at least in part on the virtual cable calibration matrix; and circuitry configured to: perform a conformance test based at least in part on the virtual cable calibration.

[0174] According to one example embodiment, an apparatus may include: a processing circuitry system; and a memory circuitry system including computer program code configured, together with the processing circuitry system, to enable the apparatus to: send a first indication to a user equipment of an estimated channel matrix of a downlink channel; send at least one downlink reference signal to the user equipment; send a second indication to the user equipment to calculate a virtual cable calibration matrix based at least in part on the estimated channel matrix; send a third indication to the user equipment to perform virtual cable calibration on at least one received baseband signal prior to demodulation, based at least in part on the virtual cable calibration matrix; and perform a conformance test based at least in part on the virtual cable calibration.

[0175] According to one example embodiment, an apparatus may include components for: sending a first indication to a user equipment (UE) of estimating a channel matrix for a downlink channel; sending at least one downlink reference signal to the UE; sending a second indication to the UE to calculate a virtual cable calibration matrix at least in part based on the estimated channel matrix; sending a third indication to the UE to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0176] The first indication of the estimated channel matrix can be transmitted via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0177] This component can also be configured to: receive confirmation from the user equipment that the channel matrix has been estimated.

[0178] The confirmation can be received via at least one of the following: explicit indication, user equipment auxiliary information, conformance test response message, implicit indication, or channel state information report.

[0179] The second indication for determining the virtual cable calibration matrix may include at least one of the following: a fourth indication for the method of determining the virtual cable calibration matrix, or a fifth indication for storing the virtual cable calibration matrix.

[0180] The second instruction may be sent via at least one of the following: radio resource control signaling, or non-access stratum signaling using user equipment dedicated conformance test functions.

[0181] This component can also be configured to: receive confirmation from the user equipment that the virtual cable calibration matrix has been determined.

[0182] The third instruction may be sent via at least one of the following: radio resource control signaling, or user equipment-specific conformance test function.

[0183] The first, second, and third instructions can be sent in parallel via the same message.

[0184] The first, second, and third instructions can be sent as compressed messages.

[0185] The second and third instructions may include one of the following: different instructions, or the same instructions.

[0186] The component can also be configured to: transmit to a user equipment a configuration for at least one downlink reference signal, wherein the channel matrix can be configured to be estimated at least in part based on the configuration.

[0187] The channel matrix of the downlink channel can include the channel matrix of the air channel between the test probe and the user equipment in the test chamber.

[0188] The component can also be configured to receive a response from a user equipment, wherein the response can be configured to acknowledge virtual cable calibration.

[0189] According to one example embodiment, a non-transitory computer-readable medium includes instructions stored thereon that, when executed by at least one processor, cause the at least one processor to: send a first indication to a user equipment of an estimated channel matrix of a downlink channel; send at least one downlink reference signal to the user equipment; send a second indication to the user equipment of calculating a virtual cable calibration matrix at least in part based on the estimated channel matrix; send a third indication to the user equipment of performing virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0190] According to one example embodiment, a non-transitory computer-readable medium includes program instructions stored thereon for at least the following operations: causing a first indication to be sent to a user equipment (UE) to estimate a channel matrix of a downlink channel; causing at least one downlink reference signal to be sent to the UE; causing a second indication to be sent to the UE to calculate a virtual cable calibration matrix at least in part based on the estimated channel matrix; causing a third indication to be sent to the UE to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least in part based on the virtual cable calibration.

[0191] According to another example embodiment, a machine-readable non-transitory program storage device may be provided, the device tangibly embodying instructions executable by a machine for performing operations including: causing a first indication to be sent to a user equipment to estimate a channel matrix of a downlink channel; causing a downlink reference signal to be sent to the user equipment; causing a second indication to be sent to the user equipment to calculate a virtual cable calibration matrix at least partially based on the estimated channel matrix; causing a third indication to be sent to the user equipment to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and performing a conformance test at least partially based on the virtual cable calibration.

[0192] According to another example embodiment, a non-transitory computer-readable medium includes instructions that, when executed by a device, cause the device to perform at least the following operations: cause a first indication to be sent to a user equipment (UE) to estimate a channel matrix of a downlink channel; cause at least one downlink reference signal to be sent to the UE; cause a second indication to be sent to the UE to calculate a virtual cable calibration matrix at least in part based on the estimated channel matrix; cause a third indication to be sent to the UE to perform virtual cable calibration on at least one received baseband signal at least in part based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least in part based on the virtual cable calibration.

[0193] A computer-implemented system includes: at least one processor and at least one non-transitory memory storing instructions that, when executed by the at least one processor, cause the system to at least: send a first indication to a user equipment of an estimated channel matrix of a downlink channel; send at least one downlink reference signal to the user equipment; send a second indication to the user equipment of calculating a virtual cable calibration matrix at least partially based on the estimated channel matrix; send a third indication to the user equipment of performing virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and perform a conformance test at least partially based on the virtual cable calibration.

[0194] A computer-implemented system includes: components for causing a first indication of a channel matrix for estimating a downlink channel to be transmitted to a user equipment; components for causing at least one downlink reference signal to be transmitted to the user equipment; components for causing a second indication to be transmitted to the user equipment to calculate a virtual cable calibration matrix at least partially based on the estimated channel matrix; components for causing a third indication to be transmitted to the user equipment to perform virtual cable calibration on at least one received baseband signal at least partially based on the virtual cable calibration matrix before demodulation; and components for performing a conformance test at least partially based on the virtual cable calibration.

[0195] As used herein, the term “non-transient” refers to a limitation on the medium itself (i.e., tangible, not signaling), rather than a limitation on the persistence of data storage (e.g., RAM vs. ROM).

[0196] It should be understood that the above description is illustrative only. Those skilled in the art can devise various alternatives and modifications. For example, the features described in the various dependent claims can be combined with each other in any suitable combination(s). Furthermore, features from the different embodiments described above can be selectively combined to form new embodiments. Therefore, the description is intended to encompass all such alternatives, modifications, and variations falling within the scope of the appended claims.

Claims

1. An apparatus comprising: At least one processor; as well as At least one non-transitory memory, the at least one non-transitory memory storing instructions, the instructions, when executed by the at least one processor, cause the device to at least: Receive a first indication of the channel matrix for estimating the downlink channel from the test equipment; Receive at least one downlink reference signal from the test equipment; In response to the first indication, the channel matrix is ​​estimated at least in part based on the at least one downlink reference signal; Receive a second instruction from the test equipment to determine the virtual cable calibration matrix; In response to the second instruction, the virtual cable calibration matrix is ​​determined at least in part based on the estimated channel matrix; The test equipment receives a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, prior to demodulation. as well as The conformance test is performed at least in part based on the virtual cable calibration.

2. The apparatus of claim 1, wherein the first indication for estimating the channel matrix is ​​received via at least one of the following: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

3. The apparatus according to claim 1 or claim 2, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: The test equipment is sent a confirmation that the channel matrix has been estimated.

4. The apparatus of claim 3, wherein the confirmation is sent via at least one of the following: Explicit instructions User equipment auxiliary information, Conformance test response message Implicit indication, or Channel status information report.

5. The apparatus according to any one of claims 1 to 4, wherein determining the second indication of the virtual cable calibration matrix comprises at least one of the following: A fourth indication for the method of determining the virtual cable calibration matrix, or The fifth instruction stores the virtual cable calibration matrix.

6. The apparatus of claim 5, wherein the virtual cable calibration matrix is ​​determined at least in part based on the indicated method for determining the virtual cable calibration matrix.

7. The apparatus according to any one of claims 1 to 6, wherein the second instruction is received via at least one of the following: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

8. The apparatus according to any one of claims 1 to 7, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: Send a confirmation to the test equipment that the virtual cable calibration matrix has been determined.

9. The apparatus according to any one of claims 1 to 8, wherein the third instruction is received via at least one of the following: Radio resource control signaling, or User equipment dedicated conformance testing function.

10. The apparatus according to any one of claims 1 to 9, wherein the first instruction, the second instruction, and the third instruction are received in parallel via the same message.

11. The apparatus according to any one of claims 1 to 10, wherein the first instruction, the second instruction, and the third instruction are received as compressed messages.

12. The apparatus according to any one of claims 1 to 9, wherein the second indication and the third indication comprise one of the following: Different instructions, or Same instructions.

13. The apparatus according to any one of claims 1 to 12, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: In response to the third instruction, the at least one received baseband signal is multiplied by the virtual cable calibration matrix before demodulation.

14. The apparatus according to any one of claims 1 to 13, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: The test device receives a configuration for the at least one downlink reference signal, wherein the channel matrix is ​​estimated at least in part based on the configuration.

15. The apparatus according to any one of claims 1 to 14, wherein the channel matrix of the downlink channel includes the channel matrix of the air channel between the test probe in the test chamber and the apparatus.

16. The apparatus according to any one of claims 1 to 15, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: Send a response to the test equipment, wherein the response is configured to acknowledge the virtual cable calibration.

17. A method comprising: The device under test receives a first indication of the channel matrix for estimating the downlink channel from the test device; Receive at least one downlink reference signal from the test equipment; In response to the first indication, the channel matrix is ​​estimated at least in part based on the at least one downlink reference signal; Receive a second instruction from the test equipment to determine the virtual cable calibration matrix; In response to the second instruction, the virtual cable calibration matrix is ​​determined at least in part based on the estimated channel matrix; The test equipment receives a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, prior to demodulation. as well as The conformance test is performed at least in part based on the virtual cable calibration.

18. The method of claim 17, wherein the first indication for estimating the channel matrix is ​​received via at least one of: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

19. The method according to claim 17 or claim 18, further comprising: The test equipment is sent a confirmation that the channel matrix has been estimated.

20. The method of claim 19, wherein the confirmation is sent via at least one of: Explicit instructions User equipment auxiliary information, Conformance test response message Implicit indication, or Channel status information report.

21. The method of any one of claims 17 to 20, wherein determining the second indication of the virtual cable calibration matrix comprises at least one of the following: A fourth indication for the method of determining the virtual cable calibration matrix, or The fifth instruction stores the virtual cable calibration matrix.

22. The method of claim 21, wherein the virtual cable calibration matrix is ​​determined at least in part based on the indicated method for determining the virtual cable calibration matrix.

23. The method according to any one of claims 17 to 22, wherein the second instruction is received via at least one of the following: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

24. The method according to any one of claims 17 to 23, further comprising: Send a confirmation to the test equipment that the virtual cable calibration matrix has been determined.

25. The method according to any one of claims 17 to 25, wherein the third instruction is received via at least one of the following: Radio resource control signaling, or User equipment dedicated conformance testing function.

26. The method according to any one of claims 17 to 25, wherein the first instruction, the second instruction, and the third instruction are received in parallel via the same message.

27. The method according to any one of claims 17 to 26, wherein the first instruction, the second instruction, and the third instruction are received as a compressed message.

28. The method according to any one of claims 17 to 25, wherein the second instruction and the third instruction comprise one of the following: Different instructions, or Same instructions.

29. The method according to any one of claims 17 to 28, further comprising: In response to the third instruction, the at least one received baseband signal is multiplied by the virtual cable calibration matrix before demodulation.

30. The method according to any one of claims 17 to 29, further comprising: The test device receives a configuration for the at least one downlink reference signal, wherein the channel matrix is ​​estimated at least in part based on the configuration.

31. The method according to any one of claims 17 to 30, wherein the channel matrix of the downlink channel includes the channel matrix of the air channel between the test probe in the test chamber and the device under test.

32. The method according to any one of claims 17 to 31, further comprising: Send a response to the test equipment, wherein the response is configured to acknowledge the virtual cable calibration.

33. An apparatus comprising components for: Receive a first indication of the channel matrix for estimating the downlink channel from the test equipment; Receive at least one downlink reference signal from the test equipment; In response to the first indication, the channel matrix is ​​estimated at least in part based on the at least one downlink reference signal; Receive a second instruction from the test equipment to determine the virtual cable calibration matrix; In response to the second instruction, the virtual cable calibration matrix is ​​determined at least in part based on the estimated channel matrix; The test equipment receives a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, prior to demodulation. as well as The conformance test is performed at least in part based on the virtual cable calibration.

34. An apparatus comprising components for performing the method according to any one of claims 17 to 32.

35. A non-transitory computer-readable medium comprising program instructions stored thereon, the program instructions being configured to perform at least the following operations: This enables the receiving of a first indication of the channel matrix for estimating the downlink channel from the test equipment; This enables the reception of at least one downlink reference signal from the test equipment; In response to the first indication, the channel matrix is ​​estimated at least in part based on the at least one downlink reference signal; This enables the receiving of a second instruction from the test equipment to determine the virtual cable calibration matrix; In response to the second instruction, the virtual cable calibration matrix is ​​determined at least in part based on the estimated channel matrix; This enables a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, received from the test equipment before demodulation. as well as The conformance test is performed at least in part based on the virtual cable calibration.

36. An apparatus comprising: At least one processor; as well as At least one non-transitory memory, the at least one non-transitory memory storing instructions, the instructions, when executed by the at least one processor, cause the device to at least: Send a first indication of the estimated channel matrix of the downlink channel to the user equipment; Send at least one downlink reference signal to the user equipment; Send a second instruction to the user equipment to calculate the virtual cable calibration matrix based at least in part on the estimated channel matrix; Send to the user equipment a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, prior to demodulation; as well as The conformance test is performed at least in part based on the virtual cable calibration.

37. The apparatus of claim 36, wherein the first indication for estimating the channel matrix is ​​transmitted via at least one of the following: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

38. The apparatus of claim 36 or claim 37, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to: The user equipment receives confirmation that the channel matrix has been estimated.

39. The apparatus of claim 38, wherein the confirmation is received via at least one of the following: Explicit instructions User equipment auxiliary information, Conformance test response message Implicit indication, or Channel status information report.

40. The apparatus of any one of claims 36 to 39, wherein determining the second indication of the virtual cable calibration matrix comprises at least one of the following: A fourth indication for the method of determining the virtual cable calibration matrix, or The fifth instruction stores the virtual cable calibration matrix.

41. The apparatus according to any one of claims 36 to 40, wherein the second instruction is transmitted via at least one of the following: Radio resource control signaling, or Non-access stratum signaling using user equipment-specific conformance testing functions.

42. The apparatus according to any one of claims 36 to 41, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to: The user equipment receives confirmation that the virtual cable calibration matrix has been determined.

43. The apparatus according to any one of claims 36 to 42, wherein the third instruction is transmitted via at least one of the following: Radio resource control signaling, or User equipment dedicated conformance testing function.

44. The apparatus according to any one of claims 45 to 43, wherein the first instruction, the second instruction, and the third instruction are transmitted in parallel via the same message.

45. The apparatus according to any one of claims 45 to 44, wherein the first instruction, the second instruction, and the third instruction are transmitted as a compressed message.

46. ​​The apparatus according to any one of claims 45 to 43, wherein the second indication and the third indication comprise one of the following: Different instructions, or Same instructions.

47. The apparatus according to any one of claims 45 to 46, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the apparatus to: The configuration for the at least one downlink reference signal is sent to the user equipment, wherein the channel matrix is ​​configured to be estimated at least in part based on the configuration.

48. The apparatus according to any one of claims 45 to 47, wherein the channel matrix of the downlink channel includes the channel matrix of the air channel between the test probe in the test chamber and the user equipment.

49. The apparatus according to any one of claims 45 to 48, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to: Receive a response from the user equipment, wherein the response is configured to acknowledge the virtual cable calibration.

50. A method comprising: The test equipment sends a first indication of the estimated channel matrix of the downlink channel to the user equipment. Send at least one downlink reference signal to the user equipment; Send a second instruction to the user equipment to calculate the virtual cable calibration matrix based at least in part on the estimated channel matrix; Send to the user equipment a third instruction to perform virtual cable calibration on at least one received baseband signal, at least in part based on the virtual cable calibration matrix, prior to demodulation; as well as The conformance test is performed at least in part based on the virtual cable calibration.

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