Techniques for determining whether EVM requirements are met

Abstract

Various aspects of the present disclosure relate to receiving (802) an indication of a receiver algorithm for evaluating an EVM requirement and an MPR table corresponding to the receiver algorithm. Aspects of the present disclosure can involve receiving (804), from a UE, a MIMO signal corresponding to a plurality of transmit antennas, where a received power of the MIMO signal satisfies a threshold based on a power class of the UE and the MPR table. Aspects of the present disclosure can further involve determining (806) an EVM of the UE based at least in part on an output of a receiver associated with the MIMO signal, and determining (808), based on the EVM and the MPR table, whether the UE satisfies the EVM requirement for a modulation type and a modulation constellation size.

Description

Technical Field

[0001] This disclosure relates to wireless communication, and more specifically, to techniques for determining whether an error vector magnitude (EVM) requirement is met. Background Technology

[0002] A wireless communication system may include one or more network communication devices, which may be referred to as network equipment (NE), supporting wireless communication with one or more user communication devices, which may also be referred to as user equipment (UE) or other suitable terms. The wireless communication system can support wireless communication with one or more user communication devices by utilizing the resources of the wireless communication system (e.g., time resources (e.g., symbols, time slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers, etc.)). Furthermore, the wireless communication system can support wireless communication across various radio access technologies, including third-generation (3G), fourth-generation (4G), fifth-generation (5G), and other suitable radio access technologies other than 5G (e.g., 5G-A, sixth-generation (6G), etc.). Summary of the Invention

[0003] The article “a” preceding an element is unrestricted and should be understood to refer to “at least one” or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. As used herein, the word “or,” as used in a list of items (e.g., a list of items beginning with phrases such as “at least one,” “one or more,” or “one or two”) indicates an inclusive list, such that a list of at least one of, for example, A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used herein, the phrase “based on” should not be construed as referring to a closed set of conditions. For example, without departing from the scope of this disclosure, an example step described as “based on condition A” may be based on both condition A and condition B. In other words, as used herein, the phrase “based on” should be interpreted in the same manner as the phrase “at least partially based on.” Furthermore, as used herein, the word “group” may comprise one or more elements.

[0004] A test apparatus for wireless communication is described. In some instances, the test apparatus may be implemented via a network element (NE) or can be implemented via an NE. The test apparatus may be configured, capable of, or operable to receive an indication of a receiver algorithm for evaluating EVM requirements and a maximum power reduction (MPR) table corresponding to the receiver algorithm; receive multiple-input multiple-output (MIMO) signals corresponding to multiple transmit antennas from a user equipment (UE), wherein the received power of the MIMO signals satisfies a threshold based on the UE's power class and the MPR table; determine the UE's EVM at least in part based on the output of a receiver associated with the MIMO signals; and determine whether the UE meets the EVM requirements for modulation type and modulation constellation size based on the EVM and the MPR table.

[0005] A processor for wireless communication is described. The processor is configured, capable, or operable to receive an instruction for a receiver algorithm for evaluating EVM requirements and an MPR table corresponding to the receiver algorithm; receive from a UE MIMO signals corresponding to a plurality of transmit antennas, wherein the received power of the MIMO signals satisfies a threshold based on the UE's power class and the MPR table; determine the UE's EVM at least in part based on the output of a receiver associated with the MIMO signals; and determine whether the UE meets the EVM requirements for modulation type and modulation constellation size based on the EVM and the MPR table.

[0006] A method is described that is performed, or can be performed, by a test apparatus for wireless communication. The method may include receiving an instruction for a receiver algorithm for evaluating EVM requirements and an MPR table corresponding to the receiver algorithm; receiving from a UE a MIMO signal corresponding to a plurality of transmit antennas, wherein the received power of the MIMO signal satisfies a threshold based on the UE's power class and the MPR table; determining the UE's EVM at least in part based on the output of a receiver associated with the MIMO signal; and determining whether the UE meets the EVM requirements for modulation type and modulation constellation size based on the EVM and the MPR table.

[0007] A UE for wireless communication is described. The UE can be configured, is capable of, or is operable to receive instructions to transmit MIMO signals; transmit the MIMO signals using multiple transmit antennas; receive instructions to apply a Performance Level Regulator (MPR), wherein the MPR is at least partially based on the EVM associated with the MIMO signals and the number of transmit antennas of the UE; and perform one or more subsequent transmissions at a certain power level based on the MPR.

[0008] A processor for wireless communication is described. The processor is configured, capable of, or operable to receive instructions to transmit MIMO signals; transmit the MIMO signals using multiple transmit antennas; receive instructions to apply a Performance Level Regulator (MPR), wherein the MPR is at least partially based on the number of EVMs associated with the MIMO signals and the number of transmit antennas of the UE; and perform one or more subsequent transmissions at a certain power level based on the MPR.

[0009] A method is described that is performed by or can be performed by a UE for wireless communication. The method may include receiving an instruction to transmit a MIMO signal; transmitting the MIMO signal using multiple transmit antennas; receiving an instruction to apply a Performance Modulation (MPR), wherein the MPR is at least partially based on the EVM associated with the MIMO signal and the number of transmit antennas of the UE; and performing one or more subsequent transmissions at a certain power level based on the MPR.

[0010] A base station for wireless communication is described. In some instances, the base station may be implemented as a network (NE) or can be implemented via a NE. The base station may be configured, capable of, or operable to identify a set of MPR tables based at least in part on a receiver algorithm used by the base station; select an MPR table from the set of MPR tables based at least in part on the UE's EVM requirements and the number of the UE's transmit antennas; transmit an indication to the UE to apply the selected MPR table; and receive one or more UL transmissions at a certain power level based on the MPR.

[0011] A processor for wireless communication is described. The processor is configured, capable of, or operable to identify a set of MPR tables based at least in part on a receiver algorithm used by a base station; select an MPR table from the set of MPR tables based at least in part on the UE's EVM requirements and the number of the UE's transmit antennas; transmit an indication to the UE to apply the selected MPR table; and receive one or more UL transmissions at a certain power level based on the MPR.

[0012] A method is described that is performed by or can be performed by a UE for wireless communication. The method may include identifying a set of MPR tables based at least in part on a receiver algorithm used by a base station; selecting an MPR table from the set of MPR tables based at least in part on the UE's EVM requirements and the number of transmit antennas of the UE; transmitting an indication to the UE to apply the selected MPR table; and receiving one or more UL transmissions at a certain power level based on the MPR. Attached Figure Description

[0013] Figure 1 Examples of wireless communication systems according to aspects of this disclosure are described.

[0014] Figure 2Examples illustrating a comparison between MPR and EVM according to aspects of this disclosure.

[0015] Figure 3 An example of a communication arrangement for calculating the EVM of a transmitter, according to aspects of this disclosure, is provided.

[0016] Figure 4 An example is provided illustrating a process for calculating EVM according to aspects of this disclosure.

[0017] Figure 5 Examples of UEs based on aspects of this disclosure are described.

[0018] Figure 6 Examples of processors according to aspects of this disclosure are described.

[0019] Figure 7 Examples of network equipment (NE) according to aspects of this disclosure are described.

[0020] Figure 8 A flowchart illustrating a method performed by a test apparatus according to aspects of this disclosure.

[0021] Figure 9 A flowchart illustrating the method performed by the UE according to aspects of this disclosure.

[0022] Figure 10 A flowchart illustrating the method performed by NE according to aspects of this disclosure. Detailed Implementation

[0023] In wireless communication devices, the phase and amplitude distortion generated by power amplifiers directly affects communication quality. In the latest communication system protocols, the most important measurement for analyzing power amplifier performance is EVM. This is a measure of modulation accuracy, or the quality of information transmitted by the power amplifier, expressed by variations in the phase and amplitude of the radio frequency (RF) signal. EVM measurements provide valuable insights into the communication link and are a key metric for transmitter performance.

[0024] EVM is used as a fundamental measure of the quality of transmit modulation. Essentially, EVM determines the upper limit of the signal-to-noise ratio achievable at the receiver in the absence of receiver noise or other interference. Generally, larger signal constellations require smaller EVM values ​​because the benefits of larger constellations are only visible at higher signal-to-noise ratios.

[0025] For example, Table 1 (from 3GPP Technical Specification (TS) 38.101-1) shows the required EVM based on constellation size (and modulation type, such as Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), or Quadrature Amplitude Modulation (QAM)). As can be seen from the table, the permissible EVM decreases from 30% for π / 2-BPSK to 3.5% for 256 QAM.

[0026]

[0027] Table 1: Requirements for Error Vector Magnitude

[0028] The purpose of the EVM requirement for the transmitter is to limit the noise floor at the receiver due to transmitter noise. For multilayer MIMO transmission, the goal of the EVM requirement is to limit the noise / error floor due to transmitter noise in each MIMO layer.

[0029] However, EVM is not the only requirement for transmitter quality. Requirements are also defined for adjacent channel leakage ratio (ACLR), spectrum emission mask (SEM), spurious emissions (SEM), and in-band emission requirements. All these requirements together determine the maximum allowable power reduction (MPR) for a given modulation type. In some cases, there are additional transmit requirements with an additional allowable maximum power reduction (A-MPR). Therefore, among these allowable power reductions, transmit power can be reduced, and thus uplink (UL) range and coverage can be reduced.

[0030] For higher-order modulations such as 16-QAM, 64-QAM, and 256-QAM (and possibly 1024-QAM), the EVM requirements are the most difficult to meet, and therefore it is the EVM requirements that determine the MPR allowed for the modulation type. This can be seen from the MPR tables shown below in Table 2 for single-antenna transmission and in Tables 3 and 4 for two-antenna transmission.

[0031] For a single transmit antenna with power category 3, the allowed MPR allocated by the internal resource block (RB) increases from 2 dB for 16 QAM to 6.5 dB for 256 QAM. For two transmit antennas with power category 2, the increase in MPR allocated by the internal RB increases from 2.5 dB for 16 QAM to 8 dB for 256 QAM. For two transmit antennas with power category 1.5, the increase in MPR allocated by the internal RB increases from 2.5 dB for 16 QAM to 8.5 dB for 256 QAM.

[0032] Because larger constellations allow for very large MPR values, the area where higher-order modulation constellations can be used is significantly reduced as the MPR value decreases. Furthermore, it should be noted that for Power Category 2 with two transmit antennas, the benefit of a 3 dB power increase is a 1 dB reduction for 16 QAM and a 1.5 dB reduction for 256 QAM due to the increased MPR allowed by the two transmit antennas. Similarly, for Power Category 1.5 with two transmit antennas, the benefit of a 6 dB power increase (relative to Power Category 3) is a 1.5 dB reduction for 16 QAM and a 2 dB reduction for 64 QAM.

[0033] As a result of the above observations, it is clear that reducing the MPR allowed by these higher-order modulations is very useful for increasing the region that can support higher-order modulations, such as those associated with Discrete Fourier Transform Extended Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) and Cyclic Prefix Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) waveforms. Furthermore, since the MPR of larger constellations is primarily driven by the EVM, any method used to reduce the EVM is highly beneficial.

[0034]

[0035] Table 2: MPR of Power Category 3

[0036]

[0037]

[0038] Table 3: MPR with dual Tx in Power Category 2

[0039]

[0040] Table 4: MPR with dual Tx in power category 1.5

[0041] This disclosure provides techniques for reducing the permissible MPR of higher-order signaling constellations. In some aspects, a pseudo-inverse and unbiased linear minimum mean square error (MMSE) receiver is used as a reference receiver to define the EVM for transmit diversity, single-layer transmission, and multi-layer transmission where the number of layers is less than the number of transmit antennas. In some aspects, the gNB can signal whether the UE is permitted or required to use the new reference receiver and the MPR table associated with reducing the MPR for higher-order signaling constellations.

[0042] Aspects of this disclosure are described in the context of wireless communication systems.

[0043] Figure 1This section describes an example of a wireless communication system 100 according to aspects of this disclosure. The wireless communication system 100 may include one or more NEs 102, one or more UEs 104, and a core network (CN) 106. The wireless communication system 100 may support various radio access technologies. In some embodiments, the wireless communication system 100 may be a 4G network, such as a Long Term Evolution (LTE) network or an LTE-A advanced network. In some other embodiments, the wireless communication system 100 may be a New Radio (NR) network, such as a 5G network, a 5G-A advanced network, or a 5G Ultra Wideband (5G-UWB) network.

[0044] In other embodiments, the wireless communication system 100 may be a combination of 4G and 5G networks, or other suitable radio access technologies (RATs), including IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20. The wireless communication system 100 may support radio access technologies other than 5G, such as 6G. Furthermore, the wireless communication system 100 may support technologies such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), or Code Division Multiple Access (CDMA).

[0045] One or more NEs 102 may be distributed across a geographical area to form a wireless communication system 100. One or more of the NEs 102 described herein may be, include, or be referred to as a network node, base station, network element, network function, network entity, radio access network (RAN), NodeB, eNodeB (eNB), next-generation NodeB (gNB), or other suitable terms. NEs 102 and UEs 104 may communicate via a communication link, which may be a wireless or wired connection. For example, NEs 102 and UEs 104 may perform wireless communication (e.g., receive signaling, transmit signaling) via a Uu interface.

[0046] NE 102 can provide a geographic coverage area within which it can support services for one or more UEs 104. For example, NE 102 and UE 104 can support wireless communication of signals associated with services (e.g., voice, video, packet data, messaging, broadcasting, etc.) based on one or more radio access technologies. In some embodiments, NE 102 can be mobile, for example, a satellite associated with a non-terrestrial network (NTN). In some embodiments, different geographic coverage areas associated with the same or different radio access technologies may overlap, but different geographic coverage areas may be associated with different NEs 102.

[0047] One or more UEs 104 may be distributed across a geographical area of ​​the wireless communication system 100. UE 104 may include or be referred to as a remote unit, mobile device, wireless device, remote device, subscriber device, transmitter device, receiver device, or some other suitable term. In some implementations, UE 104 may be referred to as a unit, station, terminal, or client, and other instances thereof. Additionally or alternatively, UE 104 may be referred to as an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a Machine Type Communication (MTC) device, and other instances thereof.

[0048] UE 104 may be able to support direct wireless communication with other UE 104 via a communication link. For example, UE 104 may support direct wireless communication with another UE 104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, UE 104 may support direct wireless communication with another UE 104 via a PC5 interface.

[0049] NE 102 may support communication with CN 106 or with another NE 102 or both. For example, NE 102 may interface with other NE 102 or CN 106 via one or more backhaul links (e.g., S1, N2, N3, or network interfaces). In some embodiments, NE 102 may communicate directly with each other. In some other embodiments, NE 102 may communicate with each other or indirectly (e.g., via CN 106). In some embodiments, one or more NE 102 may include sub-components, such as access network entities, which may be instances of access node controllers (ANCs). The ANC may communicate with one or more UE 104s via one or more other access network transmitting entities (which may be referred to as radio heads, smart radio heads, or transmit-receive points (TRPs)).

[0050] CN 106 can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. CN 106 can be an evolved packet core (EPC) or a 5G core (5GC), which may include control plane entities (e.g., Mobility Management Entity (MME), Access and Mobility Management Function (AMF)) that manage access and mobility, and user plane entities (e.g., Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), or User Plane Function (UPF)) that route packets or interconnect to external networks. In some implementations, the control plane entities may manage non-access stratum (NAS) functions of one or more UEs 104 served by one or more NEs 102 associated with CN 106, such as mobility, authentication, and bearer management (e.g., data bearers, signaling bearers, etc.).

[0051] CN 106 can communicate with the packet data network via one or more backhaul links (e.g., via S1, N2, N3, or another network interface). The packet data network may contain an application server. In some implementations, one or more UEs 104 can communicate with the application server. UE 104 can establish a session with CN 106 via NE 102 (e.g., a Protocol Data Unit (PDU) session or a PDN connection). CN 106 can use the established session (e.g., an established PDU session) to route services (e.g., control information, data, etc.) between UE 104 and the application server. A PDU session may be an instance of a logical connection between UE 104 and CN 106 (e.g., one or more network functions of CN 106).

[0052] In the wireless communication system 100, NE 102 and UE 104 can use the resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, time slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communication). In some embodiments, NE 102 and UE 104 may support different resource structures. For example, NE 102 and UE 104 may support different frame structures. In some embodiments, such as in 4G, NE 102 and UE 104 may support a single frame structure. In some other embodiments, such as in 5G and other suitable radio access technologies, NE 102 and UE 104 may support various frame structures (i.e., multiple frame structures). NE 102 and UE 104 may support various frame structures based on one or more parameter sets.

[0053] The wireless communication system 100 may support one or more parameter sets, and the parameter sets may include subcarrier spacing and cyclic prefixes. A first parameter set (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a regular cyclic prefix. In some embodiments, the first parameter set (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one time slot per subframe. A second parameter set (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a regular cyclic prefix. A third parameter set (e.g., μ=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a regular cyclic prefix or an extended cyclic prefix. A fourth parameter set (e.g., μ=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a regular cyclic prefix. A fifth parameter set (e.g., μ=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a regular cyclic prefix.

[0054] Time intervals for resources (e.g., communication resources) can be organized according to frames (also known as radio frames). Each frame may have a duration, for example, 10 milliseconds (ms). In some embodiments, each frame may contain multiple subframes. For example, each frame may contain 10 subframes, and each subframe may have a duration, for example, 1 ms. In some embodiments, each frame may have the same duration. In some embodiments, each subframe of a frame may have the same duration.

[0055] Alternatively, the time intervals of resources (e.g., communication resources) can be organized according to time slots. For example, a subframe may contain a certain number (e.g., quantity) of time slots. The number of time slots in each subframe may also depend on one or more parameter sets supported in the wireless communication system 100. For example, the first, second, third, fourth, and fifth parameter sets (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with corresponding subcarrier intervals of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can respectively utilize one time slot per subframe, two time slots per subframe, four time slots per subframe, eight time slots per subframe, and 16 time slots per subframe.

[0056] Each time slot may contain a certain number (e.g., quantity) of symbols (e.g., Orthogonal Frequency Domain Multiplexing (OFDM) symbols). In some implementations, the number (e.g., quantity) of time slots in a subframe may depend on a parameter set. For a regular cyclic prefix, a time slot may contain 14 symbols. For an extended cyclic prefix (e.g., applicable to a 60 kHz subcarrier spacing), a time slot may contain 12 symbols. The relationship between the number of symbols per time slot for regular and extended cyclic prefixes, the number of time slots per subframe, and the number of time slots per frame may depend on the parameter set. It should be understood that references to a first parameter set (e.g., μ=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and time slots.

[0057] In the wireless communication system 100, the electromagnetic (EM) spectrum can be divided into various categories, frequency bands, channels, etc., based on frequency or wavelength. For example, the wireless communication system 100 may support one or more operating frequency bands, such as frequency range names FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4 (52.6 GHz to 114.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), and FR5 (114.25 GHz to 300 GHz). In some embodiments, NE 102 and UE 104 may perform wireless communication on one or more of the operating frequency bands. In some embodiments, FR1 may be used by NE 102 and UE 104, as well as other equipment or devices, for cellular communication services (e.g., control information, data). In some implementations, FR2 can be used by NE 102 and UE 104, as well as other equipment or devices, for short-range, high data rate capabilities.

[0058] FR1 may be associated with one or more parameter sets (e.g., at least three parameter sets). For example, FR1 may be associated with a first parameter set containing a 15 kHz subcarrier spacing (e.g., μ=0); a second parameter set containing a 30 kHz subcarrier spacing (e.g., μ=1); and a third parameter set containing a 60 kHz subcarrier spacing (e.g., μ=2). FR2 may be associated with one or more parameter sets (e.g., at least two parameter sets). For example, FR2 may be associated with a third parameter set containing a 60 kHz subcarrier spacing (e.g., μ=2); and a fourth parameter set containing a 120 kHz subcarrier spacing (e.g., μ=3).

[0059] Wireless communication in unlicensed spectrum (also known as “shared spectrum”) offers several significant cost advantages compared to licensed spectrum, allowing communication to avoid covering the licensed spectrum of operators and instead use unlicensed spectrum in accordance with local regulations within a specific geographic region. From a 3GPP technology perspective, unlicensed operation can occur on the Uu interface (referred to as NR-U) or on a sidelink interface (e.g., SL-U).

[0060] For initial access, UE 104 detects candidate cells and performs downlink (DL) synchronization. For example, a gNB (e.g., an embodiment of NE 102) may transmit synchronization signals and physical broadcast channel (SS / PBCH) transmissions, referred to as synchronization signal blocks (SSBs). In various embodiments, the SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a primary information block (MIB). The synchronization signals (i.e., including the PSS and SSS) are predefined data sequences known to UE 104 (or derived using information already stored at UE 104) and located at a predefined temporal position relative to frame / subframe boundaries, etc. UE 104 searches for and uses the SSBs to obtain DL timing information (e.g., symbol timing) for DL ​​synchronization. UE 104 may also decode system information (SI) based on the SSBs. It should be noted that for beam-based communication, each DL beam may be associated with a corresponding SSB.

[0061] After performing DL synchronization and acquiring basic system information (such as MIB and System Information Block Type 1 (SIB1)), UE 104 performs UL synchronization and resource requests by selecting and transmitting a preamble on the Physical Random Access Channel (PRACH) to perform a random access procedure (referred to as the "RACH procedure"). The PRACH preamble is transmitted during the random access channel (RACH) timing, i.e., a predetermined set of time and frequency resources available for receiving the PRACH preamble. It should be noted that for beam-based communication, UE 104 may select a specific DL beam and transmit the PRACH preamble on the corresponding UL beam. In such embodiments, a mapping may exist between the SSB and the RACH timing, allowing the network to determine which beam UE 104 has selected.

[0062] In 3GPP New Radio (NR), a gNB can transmit up to 64 SSBs and up to 64 corresponding copies of the Physical Downlink Control Channel (PDCCH) and / or Physical Downlink Shared Channel (PDSCH) to deliver SIB1 in a high-frequency band (e.g., 28 GHz). This can lead to significant network energy consumption even under very low traffic load conditions. According to 3GPP Technical Report (TR) 38.864 (v18.1.0), for network energy conservation, on-demand SSB and / or SIB1 (SSB / SIB1) transmission and cells without SSB / SIB1 transmission should be considered. When a cell does not transmit SSB / SIB1, in order for UE 104 to access the cell, UE 104 should obtain the cell's SI from other associated carriers / cells and synchronize from other associated carriers / cells. When the cell is inactive for an extended period, UE 104 served by the cell can trigger SSB / SIB1 transmission by sending a request to the cell.

[0063] Figure 2 This is a block diagram illustrating one embodiment of a communication arrangement 200 for calculating the EVM of a transmitter. Arrangement 200 relates to a transmitter 202 and an evaluator 208 for calculating the EVM of the transmitter 202. As depicted, the transmitter 202 includes multiple antennas. In some embodiments, multiple transmitter antennas (Tx antennas) are arranged in one or more antenna ports (i.e., Tx antenna ports), each antenna port including multiple antennas, and each antenna having an antenna connector. In some embodiments, the transmitter 202 is an embodiment of UE 104, and the evaluator 208 is an embodiment of a test apparatus, such as NE 102 or another UE 104. However, in other embodiments, the transmitter 202 may be an embodiment of NE 102, wherein the evaluator 208 is an embodiment of a test apparatus, another NE 102, or UE 104.

[0064] Transmitter 202 generates a multilayer transmit signal for MIMO and transmits the multilayer transmit signal 204 (e.g., a multilayer MIMO signal) to evaluator 208 via propagation channel 206. As described below, evaluator 208 measures the multilayer transmit signal 204 using MIMO receiver 210 (e.g., by taking the pseudo-inverse of the channel matrix) and calculates the EVM of transmitter 202.

[0065] It should be noted that the MIMO receiver 210 of the evaluator 208 may include multiple antennas. In some embodiments, multiple receiver antennas (Rx antennas) are arranged in one or more antenna ports (i.e., Rx antenna ports), each antenna port including multiple antennas, and each antenna having an antenna connector. To improve EVM accuracy, the multilayer transmit signal 204 may be received by the MIMO receiver 210 using the same number of antennas as that used by the transmitter 202. For example, the number of Rx antennas may be the same as the number of Tx antennas. Similarly, the number of Rx antenna ports may be the same as the number of Tx antenna ports.

[0066] The EVM definition in 3GPP is defined at the output of the reference receiver. Therefore, the EVM definition is related to the receiver used to evaluate the EVM. This can be found in 3GPP TS 38.101-1 and TS 38.101-2.

[0067] For the single-antenna transmission use case in FR1, EVM is measured at the output of the zero-forcing frequency domain equalizer for CP-OFDM modulation. For DFT-s-OFDM, EVM is measured at the output of the Discrete Fourier Transform (DFT) after the frequency domain equalizer. The zero-forcing equalizer multiplies each output of the Fast Fourier Transform (FFT) by the inverse of the corresponding channel estimate.

[0068] Regarding the use case of transmit diversity with two antennas in FR1, the EVM of transmit diversity with two antennas is defined as the average of the EVMs of the first and second antennas measured separately using a single-antenna null-forcing equalizer. EVM1 and EVM2 represent the first EVM and the second EVM, respectively.

[0069] This EVM calculation corresponds to a zero-forcing MIMO receiver with two receive antennas, exhibiting worst-case correlation (correlation coefficient = 1) with transmitter noise. The zero-forcing receiver is uniquely defined as the inverse of the 2×2 channel matrix H, but here it is virtual in the sense that there is no second layer and no reference symbol associated with the second layer.

[0070] It is known that zero-forcing receivers are inferior to linear unbiased MMSE receivers, and the difference can be significant. In the optimal case where transmitter noise is independent, based on inverting the channel H with a zero-forcing receiver, the EVM is reduced by 3 dB relative to the receiver.

[0071] For the use case of transmit diversity with four antennas in FR1, this EVM calculation corresponds to a zero-forcing MIMO receiver with four receive antennas, which has the worst-case correlation of transmitter noise (correlation coefficient = 1). The zero-forcing receiver is uniquely defined as the inverse of the 4×4 channel matrix H, but here it is virtual in the sense that there is only one layer and no reference symbols associated with the second, third and fourth layers.

[0072] Regarding the use case of multi-layer MIMO transmission (e.g., two layers) in FR1, the EVM is defined per layer, and both layers must satisfy the EVM requirements. The EVM is measured at the output of a zero-forcing MIMO receiver, uniquely defined as the inverse of a 2×2 channel matrix H. This receiver is actually implemented using reference symbols for each layer and possibly also decision-guided channel estimation (non-virtual). The data symbol estimate x is given as:

[0073]

[0074] Where y is the 2×1 signal at the antenna connector, and H is the 2×2 channel. If a 2×2 precoding matrix W is applied to the data symbols before transmission, then the receiver is given as:

[0075] .

[0076] For FR1, all measurements are conducted and performed at the antenna connector. For FR2, all measurements are radiated.

[0077] Furthermore, for FR2, the UE can transmit a single layer from two different polarizations. For FR2, the reference receiver used by the test equipment is a pseudo-inverse receiver, which is given as:

[0078] ,

[0079] Where y is the 2×1 signal at the antenna connector, H is the 2×2 channel, the superscript H indicates the conjugate transpose of the matrix, and x is the estimate of the data symbol.

[0080] If a 2×1 precoding vector w is applied to the data symbol before transmission, then the pseudo-inverse receiver is given as:

[0081] .

[0082] One drawback of pseudo-inverse receivers is that their performance is not independent of the channel between the UE and the gNB or between the UE and the test equipment receiver. This means that the EVM visible at the receiver depends on the channel between the transmitter and receiver, whereas ideally, transmitter quality metrics should not depend on the channel between the transmitter and receiver. A second drawback of pseudo-inverse receivers is that they are not optimal because they do not address the correlation of transmitter noise. However, when transmitter noise is uncorrelated and has equal variance, the transmitter noise is 3 dB lower than that of a zero-forcing receiver.

[0083] A superior linear receiver would be an unbiased linear MMSE receiver that utilizes the correlation of transmitter noise. For an unbiased linear MMSE receiver, it can be demonstrated that the EVM is no worse than the EVM of the better of the two transmit antennas. In any case, an unbiased linear MMSE receiver is always as good as or better than a pseudo-inverse receiver. An unbiased linear MMSE receiver for single-layer transmission is given as:

[0084]

[0085] in

[0086] .

[0087] In this expression, H represents the M×1 channel matrix, w represents the M×1 precoding vector, and Σ is the covariance of the transmitter noise. The EVM corresponding to the MMSE receiver is given as:

[0088] .

[0089] For an FR2 with two layers of transmission, the reference receiver is a zero-forcing receiver, which is uniquely defined as the inverse of the 2×2 channel matrix H.

[0090] At least in the case of a single-layer transmitter with two or four transmit antennas in FR1, a virtual null-forcing receiver is used to most closely resemble the receiver used for the single-antenna EVM definition. Furthermore, a worst-case correlation of transmitter noise is assumed when defining the test, because this receiver is not actually implemented by the test equipment. Instead, the EVM is measured individually for each antenna connector. Therefore, it is impossible to observe the effects of transmitter noise correlation in the test, and thus a worst-case assumption is made. Another reason for assuming a worst-case transmitter noise when deriving the EVM is to consider the fact that one of the mechanisms for making transmitter noise correlated, namely antenna coupling, does not exist in conducted tests.

[0091] When defining EVM tests, test equipment suppliers were reluctant to implement EVM definitions that required joint signal processing at two antenna connectors. However, since test equipment suppliers have now agreed to implement zero-forcing MIMO receivers for two-layer transmissions, test equipment no longer prevents the use of receivers that require joint signal processing at multiple antennas for EVM definitions.

[0092] To improve UL range, coverage, and capacity, and to reduce operator capital expenditures, it is desirable to enable devices to transmit at higher power over the UL. As discussed above, for larger QAM constellations such as 16-QAM, 64-QAM, and 256-QAM (and potentially 1024-QAM), MPR requirements should be developed separately for more advanced receivers. Specifically, it should be possible to reduce the MPR allowed by multi-antenna transmissions with advanced receivers.

[0093] Figure 3 Chart 300 depicts a comparison between NR MPR and EVM for internal allocation within CP-OFDM. (See chart 300.) Figure 3 As described, the permissible MPR varies depending on the EVM used for single-antenna transmission.

[0094] For smaller signal constellations such as QAM, as PA power decreases, EVM requirements are met before ACLR and SEM requirements, and therefore the permissible MPR is the power reduction required to meet ACLR and SEM requirements. Conversely, for larger constellations such as 64 QAM and 256 QAM, ACLR and SEM requirements are met before EVM requirements. Therefore, the permissible MPR for 64 QAM and 256 QAM is the power reduction required to meet EVM requirements.

[0095] If the transmitter noise is independent and has equal variance on both transmit antennas, then the EVM at the output of the pseudo-inverse or MMSE receiver will be halved relative to the EVM measured on each antenna individually. Similarly, if the transmitter noise is independent and has equal variance on all four transmit antennas, then the EVM at the output of the pseudo-inverse or MMSE receiver will be 25% lower relative to the EVM measured on each antenna individually.

[0096] Therefore, for single-layer transmission with two and four antennas, the EVM of each antenna can be increased respectively. And twice as many, while still meeting EVM requirements. In view of this, it is reasonable to consider using these more advanced receivers to define the EVM for FR1 single-layer transmission.

[0097] from Figure 3 It is evident that EVM has been relaxed. This corresponds to a 1 dB reduction in the desired MPR. From the same Figure 3 As can be seen, a 2-fold relaxation of the EVM corresponds to an approximately 2 dB reduction in the required MPR.

[0098] There are at least two cases in which more advanced receivers can be used to reduce the required (and allowed) MPR for transmitting larger signal constellations (such as 64 QAM and 256 QAM). The two cases are: i) transmit diversity or single-layer transmission with M antennas; and ii) multi-layer transmission, where the number of layers is less than the number of transmit antennas.

[0099] For use cases involving transmit diversity or single-layer transmission with M antennas, if the transmitter noise is uncorrelated, then the EVM can be reduced. Even with worst-case correlation of transmitter noise, the EVM will not be worse than the maximum value of the EVM for the M antennas evaluated individually at the antenna connector. Generally, it is unreasonable to assume that the transmitter noise on all M antennas is perfectly correlated, given that not all antenna pairs are adjacent. For example, if the polarizations of the transmitter antennas are misaligned or orthogonal, then minimal antenna coupling can be assumed.

[0100] Since it cannot be assumed that the transmitter noise is uncorrelated, simply reducing the required EVM is sufficient. That is insufficient. Instead, the test setup can implement a real receiver with M antennas, which can be a linear unbiased MMSE receiver, where the data symbol x is estimated as:

[0101] ,

[0102] and

[0103]

[0104] Where H represents the M×1 channel matrix, w represents the M×1 precoding vector, and ∑ is the covariance of the transmitter noise. Alternatively, a pseudo-inverse receiver can be used, which is given as:

[0105] .

[0106] Any of these receivers (i.e., linear unbiased MMSE or pseudo-inverse receiver) can be used to evaluate the EVM and develop new, reduced MPR values ​​relative to the MPR values ​​in the specification. However, since not all gNBs will use these advanced receivers, the gNB may need to signal to the UE that it will use the MPR table associated with a more advanced receiver. More specifically, the gNB may signal that it will use one or more sets of MPR tables. In one embodiment, if the UE has pre-configured MPR tables, the gNB may signal an indication of its receiver type or which MPR tables(s) will be used.

[0107] In some cases, it may be necessary to consider transmitter correlation due to antenna coupling, which occurs during antenna use but is not observed in conducted tests. The EVM measured at the receiver output in conducted measurements will only reflect the correlation of transmitter noise within the UE itself. If necessary, this correlation due to the antenna can be handled in several ways:

[0108] First, a margin is agreed upon regarding the permitted MPR or the EVM requirements at the receiver output relative to the requirements in Table 1 (above). Second, coupling is introduced across the antenna connector.

[0109] This second approach presents some challenges in implementation, particularly regarding the agreement on the coupling amplitude, or the need to apply multiple phases during test transmissions because performance may depend on the phase of the coupler.

[0110] When multiple phases are applied, the UE antenna coupling will be evaluated, and the corresponding coupling coefficient will be applied during testing. Alternatively, based on the coupling coefficient measurement, the coupling measured in dB can be categorized into one of several classes, such as 10 to 15, 15 to 20, 20 to 25, etc. Here, a coupling coefficient of X dB means a decrease in coupled power of X dB from one antenna to an adjacent antenna. For each class, the coupling coefficient applied during testing will be the smaller of the two isolation values ​​that define the class (e.g., for a class with coupling of 10 dB to 15 dB, a value of 10 dB will be used).

[0111] Furthermore, determining the antenna coupling for more than two antennas requires determining the coupling of all antenna pairs. Therefore, for four antennas, the number of antenna pairs is 6.

[0112] In summary, the advantages of using M antennas to transmit a single layer are as follows: i) the transmit power can be increased by a factor of M; ii) the EVM requirement per antenna can be reduced compared to the same power transmitted by a single antenna. times; iii) such as through Figure 3 The EVM vs. MPR curves show that the MPR required to meet the EVM requirements can be reduced by several dB.

[0113] For transmit diversity or single-layer transmission from multiple antennas, defining new reduced MPR requirements for improved receivers includes 1) defining the EVM as the output of a linear unbiased MMSE receiver or a pseudo-inverse receiver; 2) determining the MPR required to satisfy the EVM of these receivers; 3) generating an MPR table based on these MPR values; and 4) (e.g., by a gNB) signaling to the UE whether the improved MPR table is available.

[0114] It should be noted that the MPR must be specified corresponding to the number of transmitting antennas used. For example, the MPR can be specified for two, three, four, and eight transmitting antennas.

[0115] For MIMO transmissions where the number of MIMO layers L is less than the number of transmit antennas M, a pseudo-inverse and unbiased linear MMSE receiver can also be defined to transmit L MIMO layers from M antennas, where L is less than or equal to M. As previously stated, the pseudo-inverse receiver is given as:

[0116] .

[0117] Here, y has dimension M×1, x has dimension L×1, the channel H has dimension M×M, and the precoding matrix W has dimension M×L. An unbiased linear MMSE receiver for this case is given as:

[0118]

[0119] in

[0120]

[0121] And P is composed of diag(Q) 11 Q 22 , …, Q MM Given a diagonal matrix, where

[0122] .

[0123] When the number of layers L is less than the number of transmit antennas M, and the transmitter noise is uncorrelated and has equal variance, it can be shown that the transmitter noise at the output of the pseudo-inverse and unbiased linear MMSE receiver is reduced by a factor of M / L for each layer, and the EVM of each layer is reduced. .

[0124] Therefore, for L-layer MIMO transmission where L is less than the number of transmit antennas M, the new reduced MPR requirement for the improved receiver includes: 1) defining the EVM as the output of a linear unbiased MMSE receiver or a pseudo-inverse receiver; 2) determining the MPR required to satisfy the EVM of different receivers for different values ​​of L less than M; 3) generating an MPR table based on these MPR values; and 4) (e.g., by gNB) signaling to the UE whether the improved MPR table can be used.

[0125] It should be noted that the MPR must be specified corresponding to the number of transmitting antennas used. For example, the MPR can be specified for two, three, four, and eight transmitting antennas.

[0126] Figure 4 A process 400 for calculating the EVM of a transmitting device (e.g., UE 402) according to aspects of this disclosure is described. Process 400 involves UE 402 (e.g., an embodiment of UE 104 and transmitter 202), test equipment 404 (e.g., an embodiment of evaluator 208), and network node 406 (e.g., an embodiment of NE 102, CN 106, and / or gNB).

[0127] At step 1, test equipment 404 identifies a receiver algorithm for evaluating, for example, the EVM requirements of UE 402 (see box 408). Optionally, test equipment 404 may receive, for example, an instruction from network node 406 regarding the receiver algorithm to be used to evaluate the EVM requirements.

[0128] At step 2, test equipment 404 receives an MPR table corresponding to the receiver algorithm (see box 410). In one embodiment, network node 406 may transmit indications of one or more MPR tables to test equipment 404. Alternatively, test equipment 404 may be pre-configured with MPR tables, wherein at step 2, the test equipment retrieves one or more MPR tables corresponding to the receiver algorithm, for example, from memory.

[0129] It should be noted that the MPR table is used by the test equipment, not generated by it. In some embodiments, the MPR table for receiver type and number of layers will be determined by simulation or measurement. In such embodiments, the MPR table may be specified (e.g., captured in the 3GPP specification).

[0130] In step 3, the test equipment 404 transmits (and the UE 402 receives) a command to transmit a MIMO signal (see signaling 412).

[0131] At step 4, UE 402 transmits (and test equipment 404 receives) MIMO signals corresponding to multiple transmit antennas (see signaling 414). Here, the received power of the MIMO signals meets a threshold based on the UE's power class and the MPR table (e.g., not less than the threshold).

[0132] At step 5, test equipment 404 determines the UE’s EVM based at least in part on the output of the receiver associated with the MIMO signal (see box 416).

[0133] In step 6, the test equipment 404 determines whether the UE meets the EVM requirements based on the EVM and MPR tables, taking into account the modulation type and modulation constellation size (see signaling 418).

[0134] At step 7, UE 402 receives an indication to apply an MPR (e.g., an improved MPR as described above), wherein the MPR is based at least in part on the EVM associated with the MIMO signal and the number of the UE's transmit antennas (see box 420). In the depicted embodiment, the indication is received from network node 406. For example, network node 406 may transmit an indication to apply a selected MPR table. In another embodiment, UE 402 may receive the MPR indication from test equipment 404.

[0135] At step 8, UE 402 transmits (and network node 406 receives) one or more UL transmissions at a certain power level based on MPR (see signaling 422). Therefore, UE 402 can use the improved MPR for subsequent transmissions to the network.

[0136] Figure 5 An example of a UE 500 according to aspects of this disclosure is described. UE 500 may include a processor 502, a memory 504, a controller 506, and a transceiver 508. The processor 502, memory 504, controller 506, or transceiver 508, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operatively, communicatively, functionally, electronically, electrically).

[0137] Processor 502, memory 504, controller 506, or transceiver 508, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may be a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured to or otherwise support components for performing the functions described in this disclosure.

[0138] Processor 502 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, central processing unit (CPU), ASIC, field-programmable gate array (FPGA), or any combination thereof). In some embodiments, processor 502 may be configured to operate memory 504. In some other embodiments, memory 504 may be integrated into processor 502. Processor 502 may be configured to execute computer-readable instructions stored in memory 504 to cause UE 500 to perform various functions of this disclosure.

[0139] Memory 504 may comprise volatile or non-volatile memory. Memory 504 may store computer-readable, computer-executable code containing instructions that, when executed by processor 502, cause UE 500 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 504 or another type of memory. Computer-readable medium includes both non-transitory computer storage media and communication media, wherein the communication media includes any media that facilitates the transfer of a computer program from one place to another. Non-transitory storage media may be any available media accessible by a general-purpose or special-purpose computer.

[0140] In some embodiments, processor 502 and memory 504 coupled to processor 502 may be configured to cause UE 500 to perform various functions described herein (e.g., operation, signaling) (e.g., instructions stored in memory 504 executed by processor 502). In some embodiments, processor 502 may include multiple processors, and memory 504 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be individually or collectively configured to perform various functions of UE 500 as disclosed herein (e.g., operation, signaling).

[0141] The processor 502, coupled to the memory 504, can be configured to enable the UE 500 to receive instructions to transmit MIMO signals and methods for transmitting MIMO signals using multiple transmit antennas. In some embodiments, the MIMO signal includes an integer number of transmit layers, wherein the integer number of transmit layers is less than the number of transmit antennas.

[0142] The processor 502 coupled to the memory 504 can be configured to enable the UE 500 to receive an instruction to apply MPR and a method for performing one or more subsequent transmissions at a certain power level based on the MPR, wherein the MPR is at least partially based on the EVM associated with the MIMO signal and the number of the UE's transmit antennas.

[0143] In some embodiments, the processor 502 coupled to the memory 504 may be configured to enable the UE 500 to apply a set of MPR tables. In some embodiments, the set of MPR tables is further based on a receiver algorithm, wherein the receiver algorithm includes a linear unbiased MMSE receiver or a pseudo-inverse MIMO receiver.

[0144] In some embodiments, the set of MPR tables is further based on the number of transmit layers associated with the MIMO signal. In some embodiments, the indication of applying the MPR further includes an indication of which MPR tables in the set of MPR tables will be used for one or more subsequent transmits.

[0145] Controller 506 manages the input and output signals of UE 500. Controller 506 can also manage peripheral devices not integrated into UE 500. In some embodiments, controller 506 may utilize an operating system (OS) such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some embodiments, controller 506 may be implemented as part of processor 502.

[0146] In some embodiments, UE 500 may include at least one transceiver 508. In other embodiments, UE 500 may have more than one transceiver 508. Transceiver 508 may represent a wireless transceiver. Transceiver 508 may include one or more receiver chains 510, one or more transmitter chains 512, or a combination thereof.

[0147] Receiver chain 510 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, receiver chain 510 may include one or more antennas for receiving signals over the air or over a wireless medium. Receiver chain 510 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 510 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 510 may include at least one decoder for decoding / processing the demodulated signal to receive the transmitted data.

[0148] Transmitter chain 512 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 512 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 512 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 512 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0149] Figure 6 An example of a processor 600 according to aspects of this disclosure is described. Processor 600 may be an example of a processor configured to perform various operations according to the examples described herein. Processor 600 may include a controller 602 configured to perform various operations according to the examples described herein. Processor 600 may optionally include at least one memory 604, which may be, for example, an L1 / L2 / L3 cache. Additionally or alternatively, processor 600 may optionally include one or more arithmetic logic units (ALUs) 606. One or more of these components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0150] Processor 600 may be a processor chipset and includes a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receive, acquire, retrieve, transmit, output, forward, store, determine, identify, access, write, read) according to the examples described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory native to the processor chipset (e.g., processor 600) or contained within the processor chipset (e.g., processor 600)) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), and others).

[0151] Controller 602 can be configured to manage and coordinate various operations of processor 600 (e.g., signaling, receiving, acquiring, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, and reading) to enable processor 600 to support various operations according to the examples described herein. For example, controller 602 can operate as a control unit of processor 600, generating control signals that manage the operation of various components of processor 600. These control signals include enabling or disabling functional units, selecting data paths, initiating memory accesses, and coordinating operation timing.

[0152] Controller 602 may be configured to fetch (e.g., fetch, retrieve, receive) instructions from memory 604 and determine subsequent instructions to be executed to enable processor 600 to support various operations according to the examples described herein. Controller 602 may be configured to track the memory addresses of instructions associated with memory 604. Controller 602 may be configured to decode instructions to determine the operations to be performed and the operands involved. For example, controller 602 may be configured to interpret instructions and determine control signals to be output to other components of processor 600 to enable processor 600 to support various operations according to the examples described herein. Additionally or alternatively, controller 602 may be configured to manage data flow within processor 600. Controller 602 may be configured to control data transfers between registers, arithmetic logic unit (ALU), and other functional units of processor 600.

[0153] Memory 604 may include one or more caches (e.g., memory local to processor 600 or included in processor 600) or other memories, such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some embodiments, memory 604 may reside within or on the processor chipset (e.g., local to processor 600). In some other embodiments, memory 604 may reside outside the processor chipset (e.g., remote from processor 600).

[0154] Memory 604 may store computer-readable, computer-executable code containing instructions that, when executed by processor 600, cause processor 600 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. Controller 602 and / or processor 600 may be configured to execute computer-readable instructions stored in memory 604 to cause processor 600 to perform various functions. For example, processor 600 and / or controller 602 may be coupled to or coupled to memory 604, and processor 600, controller 602, and memory 604 may be configured to perform the various functions described herein. In some instances, processor 600 may include multiple processors, and memory 604 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be individually or collectively configured to perform the various functions described herein.

[0155] One or more ALUs 606 may be configured to support various operations according to the examples described herein. In some embodiments, one or more ALUs 606 may reside within or on a processor chipset (e.g., processor 600). In some other embodiments, one or more ALUs 606 may reside outside the processor chipset (e.g., processor 600). One or more ALUs 606 may perform one or more calculations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALUs 606 may receive input operands and an opcode that determines the operation to be performed. One or more ALUs 606 may be configured with various logic and arithmetic circuitry, including adders, subtractors, shifters, and logic gates, to process and manipulate data according to the operation. Alternatively, one or more ALU 606s may support logical operations such as AND, OR, XOR, NOR, and NAND, enabling one or more ALU 606s to handle conditional operations, comparisons, and bitwise operations.

[0156] In various implementations, processor 600 may support various functions (e.g., operation, signaling) according to examples disclosed herein. For example, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to receive instructions to transmit MIMO signals; transmit MIMO signals using multiple transmit antennas; receive instructions to apply MPR, wherein the MPR is at least partially based on the number of EVMs associated with the MIMO signals and the number of transmit antennas of the UE; and perform one or more subsequent transmissions at a certain power level based on the MPR. Furthermore, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to perform one or more functions of the UE as described herein (e.g., operation, signaling).

[0157] In various implementations, processor 600 may support the functionality of a test apparatus according to examples disclosed herein. For example, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to receive instructions for a receiver algorithm for evaluating EVM requirements and an MPR table corresponding to the receiver algorithm; receive MIMO signals corresponding to multiple transmit antennas from a UE, wherein the received power of the MIMO signals satisfies thresholds based on the UE's power class and the MPR table; determine the UE's EVM based at least in part on the output of the receiver associated with the MIMO signals; and determine whether the UE meets the EVM requirements for modulation type and modulation constellation size based on the EVM and the MPR table. Furthermore, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to perform one or more functions of the test apparatus as described herein (e.g., operation, signaling).

[0158] In various implementations, processor 600 may support the functionality of a base station or gNB according to examples disclosed herein. For example, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to identify a set of MPR tables at least in part based on a receiver algorithm used by the base station; select an MPR table from the set of MPR tables at least in part based on the UE's EVM requirements and the number of the UE's transmit antennas; transmit an indication to the UE of the selected MPR table; and receive one or more UL transmissions at a certain power level based on the MPR. In some embodiments, the receiver algorithm includes a linear unbiased MMSE receiver or a pseudo-inverse MIMO receiver. Furthermore, controller 602 coupled to memory 604 may be configured, enabled, or operable to cause processor 600 to perform one or more functions of the NE as described herein (e.g., operation, signaling).

[0159] Figure 7 An example of NE 700 according to aspects of this disclosure is described. NE 700 may include a processor 702, a memory 704, a controller 706, and a transceiver 708. The processor 702, memory 704, controller 706, or transceiver 708, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operatively ground, communicatively ground, functional ground, electronic ground, electrical ground).

[0160] Processor 702, memory 704, controller 706, or transceiver 708, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may be a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured or otherwise supporting components for performing the functions described in this disclosure.

[0161] Processor 702 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, or any combination thereof). In some embodiments, processor 702 may be configured to operate memory 704. In some other embodiments, memory 704 may be integrated into processor 702. Processor 702 may be configured to execute computer-readable instructions stored in memory 704 to cause NE 700 to perform various functions of this disclosure.

[0162] Memory 704 may comprise volatile or non-volatile memory. Memory 704 may store computer-readable, computer-executable code containing instructions that, when executed by processor 702, cause NE 700 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 704 or another type of memory. Computer-readable medium includes both non-transitory computer storage media and communication media, wherein the communication media includes any media that facilitates the transfer of a computer program from one place to another. Non-transitory storage media may be any available media accessible by a general-purpose or special-purpose computer.

[0163] In some embodiments, processor 702 and memory 704 coupled to processor 702 may be configured to cause NE 700 to perform various functions described herein (e.g., operation, signaling) (e.g., instructions stored in memory 704 executed by processor 702). In some embodiments, processor 702 may include multiple processors, and memory 704 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be individually or jointly configured to perform various functions of NE 700 as disclosed herein (e.g., operation, signaling).

[0164] In various implementations, the NE 700 may support the functionality of test apparatus according to examples disclosed herein. For example, a processor 702 coupled to a memory 704 may be configured to enable the NE 700 to receive MIMO signals corresponding to multiple transmit antennas from a UE, wherein the received power of the MIMO signals satisfies (e.g., not less than) a threshold based on the UE's power class and MPR table.

[0165] The processor 702 coupled to the memory 704 can be configured to enable the NE 700 to determine the UE's EVM at least in part based on the output of the receiver associated with the MIMO signal, and to provide a method for determining whether the UE meets the EVM requirements for modulation type and modulation constellation size based on the EVM and MPR table.

[0166] In some embodiments, the EVM is further based on a receiver algorithm. In some embodiments, the receiver algorithm includes a linear unbiased MMSE receiver or a pseudo-inverse MIMO receiver.

[0167] In some embodiments, the MPR table further corresponds to the number of transmit antennas associated with the MIMO signal, and the MIMO signal includes an integer number of transmit layers, wherein the integer number of transmit layers is less than the number of transmit antennas.

[0168] In some embodiments, the MPR table is further based on the number of transmit layers associated with the MIMO signal. In some embodiments, the EVM is further based on radiation measurements of the MIMO signal. In some embodiments, the MPR is further based on transmitter noise correlation based on antenna coupling of multiple transmit antennas.

[0169] In various implementations, the NE 700 may support the functionality of a base station or gNB according to examples disclosed herein. For example, a processor 702 coupled to memory 704 may be configured to enable the NE 700 to identify a set of MPR tables based at least in part on a receiver algorithm used by the base station. In some embodiments, the receiver algorithm includes a linear unbiased MMSE receiver or a pseudo-inverse MIMO receiver.

[0170] The processor 702, coupled to the memory 704, can be configured such that the NE 700 selects an MPR table from the set of MPR tables based at least in part on the UE's EVM requirements and the number of the UE's transmit antennas. In some embodiments, the set of MPR tables is further based on the number of transmit layers associated with one or more UL transmits, and the EVM requirements are based at least in part on the receiver algorithm.

[0171] In some embodiments, the processor 702 coupled to the memory 704 may be configured to allow the NE 700 to further select an MPR table based on EVM measurements associated with the number of transmit antennas of the UE. In some embodiments, the selected MPR table corresponds to the number of transmit antennas of the UE and the number of transmit layers associated with the MIMO signal.

[0172] The processor 702, coupled to the memory 704, can be configured to enable the NE 700 to transmit an indication of the MPR table selected by the application to the UE. The processor 702, coupled to the memory 704, can also be configured to enable the NE 700 to receive one or more UL transmissions at a certain power level based on the MPR.

[0173] Controller 706 manages the input and output signals of NE 700. Controller 706 can also manage peripheral devices not integrated into NE 700. In some embodiments, controller 706 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some embodiments, controller 706 may be implemented as part of processor 702.

[0174] In some embodiments, the NE 700 may include at least one transceiver 708. In other embodiments, the NE 700 may have more than one transceiver 708. The transceiver 708 may represent a wireless transceiver. The transceiver 708 may include one or more receiver chains 710, one or more transmitter chains 712, or a combination thereof.

[0175] Receiver chain 710 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, receiver chain 710 may include one or more antennas for receiving signals over the air or over a wireless medium. Receiver chain 710 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 710 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 710 may include at least one decoder for decoding / processing the demodulated signal to receive the transmitted data.

[0176] Transmitter chain 712 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 712 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 712 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 712 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0177] Figure 8An embodiment of method 800 according to aspects of this disclosure is depicted. In various embodiments, operation of method 800 may be implemented by a test apparatus (e.g., an NE as described herein). In some embodiments, the NE may execute a set of instructions to control the functional elements of the NE to perform the described functions.

[0178] At step 802, method 800 may include receiving an instruction for a receiver algorithm used to evaluate EVM requirements and an MPR table corresponding to the receiver algorithm. The operation of step 802 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 802 may be as described in references... Figure 7 The described NE execution.

[0179] At step 804, method 800 may include receiving MIMO signals corresponding to a plurality of transmit antennas from the UE, wherein the received power of the MIMO signals satisfies a threshold based on the UE's power class and MPR table. The operation of step 804 may be performed according to the examples described herein. In some embodiments, aspects of the operation of step 804 may be as described in references... Figure 7 The described NE execution.

[0180] At step 806, method 800 may include determining the UE's EVM based at least in part on the output of a receiver associated with the MIMO signal. The operation of step 806 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 806 may be as described in references... Figure 7 The described NE execution.

[0181] At step 808, method 800 may include determining whether the UE meets the EVM requirements based on the EVM and MPR tables, for modulation type and modulation constellation size. The operation of step 808 may be performed according to the examples described herein. In some embodiments, aspects of the operation of step 808 may be as described in the references... Figure 7 The described NE execution.

[0182] It should be noted that the method 800 described herein describes one possible implementation, and the operation and steps may be rearranged or otherwise modified, and other implementations are possible.

[0183] Figure 9 An embodiment of method 900 according to aspects of this disclosure is depicted. In various embodiments, operation of method 900 may be implemented by a radio node (e.g., a UE or NE as described herein). In some embodiments, the UE may execute a set of instructions to control the functional elements of the UE to perform the described function. In other embodiments, the NE may execute a set of instructions to control the functional elements of the NE to perform the described function.

[0184] At step 902, method 900 may include instructions to receive a transmitted MIMO signal. The operation of step 902 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 902 may be as described in references... Figure 5 The UE execution described.

[0185] At step 904, method 900 may include transmitting MIMO signals using multiple transmit antennas. The operation of step 904 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 904 may be as described in references... Figure 5 The UE execution described.

[0186] At step 906, method 900 may include receiving an indication of an application MPR, the MPR being at least partially based on the number of EVMs associated with the MIMO signal and the number of transmit antennas of the UE. Operation of step 906 may be performed according to examples as described herein. In some embodiments, aspects of operation of step 906 may be as described in references... Figure 5 The UE execution described.

[0187] At step 908, method 900 may include performing one or more subsequent transmissions at a certain power level based on the MPR. The operation of step 908 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 908 may be as described in references... Figure 5 The UE execution described.

[0188] It should be noted that the method 900 described herein describes one possible implementation, and the operation and steps may be rearranged or otherwise modified, and other implementations are possible.

[0189] Figure 10 An embodiment of method 1000 according to aspects of this disclosure is depicted. In various embodiments, operation of method 1000 may be implemented by a base station (e.g., an NE as described herein). In some embodiments, the NE may execute a set of instructions to control the functional elements of the NE to perform the described functions.

[0190] At step 1002, method 1000 may include identifying a set of MPR tables based at least in part on a receiver algorithm used by the base station. The operation of step 1002 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 1002 may be as described in references... Figure 7 The described NE execution.

[0191] At step 1004, method 1000 may include selecting an MPR table from the set of MPR tables, at least in part based on the UE's EVM requirements and the number of the UE's transmit antennas. The operation of step 1004 may be performed according to examples as described herein. In some embodiments, aspects of the operation of step 1004 may be as described in references... Figure 7 The described NE execution.

[0192] At step 1006, method 1000 may include transmitting an indication to the UE of the MPR table selected by the application. The operation of step 1006 may be performed according to the examples described herein. In some embodiments, aspects of the operation of step 1006 may be as described in references... Figure 7 The described NE execution.

[0193] At step 1008, method 1000 may include receiving one or more UL transmissions at a certain power level based on MPR. The operation of step 1008 may be performed according to the examples described herein. In some embodiments, aspects of the operation of step 1008 may be as described in the references... Figure 7 The described NE execution.

[0194] It should be noted that the method 1000 described herein describes one possible implementation, and the operation and steps may be rearranged or otherwise modified, and other implementations are possible.

[0195] The description herein is provided to enable those skilled in the art to make or use this disclosure. Various modifications to this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A testing apparatus for wireless communication, comprising: At least one memory; and At least one processor, coupled to the at least one memory and configured to enable the test apparatus: Receive an instruction for a receiver algorithm used to evaluate the error vector magnitude (EVM) requirement and a maximum power reduction (MPR) table corresponding to the receiver algorithm; Receive multiple-input multiple-output (MIMO) signals corresponding to multiple transmit antennas from a user equipment (UE), wherein the received power of the MIMO signals satisfies a threshold based on the power class of the UE and the MPR table; The UE's EVM is determined at least in part based on the output of the receiver associated with the MIMO signal; and Based on the EVM and the MPR table, it is determined whether the UE meets the EVM requirements for the modulation type and modulation constellation size.

2. The test equipment according to claim 1, wherein the EVM is further based on the receiver algorithm.

3. The test equipment according to claim 1, wherein the receiver algorithm includes a linear unbiased minimum mean square error (MMSE) receiver or a pseudo-inverse MIMO receiver.

4. The test apparatus of claim 1, wherein the MPR table further corresponds to the number of transmit antennas associated with the MIMO signal, wherein the MIMO signal comprises an integer number of transmit layers, and wherein the integer number of transmit layers is less than the number of transmit antennas.

5. The test apparatus of claim 1, wherein the MPR table is further based on the number of transmit layers associated with the MIMO signal.

6. The test apparatus of claim 1, wherein the EVM is further based on radiation measurements of the MIMO signal.

7. The test apparatus of claim 1, wherein the MPR is further based on transmitter noise correlation based on antenna coupling of the plurality of transmit antennas.

8. The test apparatus of claim 1, wherein the at least one processor is configured to instruct the test apparatus to indicate the MPR to the UE.

9. A user equipment (UE) for wireless communication, comprising: At least one memory; and At least one processor, coupled to and configured to enable the UE to: Receive commands to transmit multiple-input multiple-output (MIMO) signals; The MIMO signal is transmitted using multiple transmitting antennas; The system receives an instruction to apply maximum power reduction (MPR), wherein the MPR is based at least in part on the error vector magnitude (EVM) associated with the MIMO signal and the number of transmit antennas of the UE. and Based on the MPR, one or more subsequent transmissions are performed at a certain power level.

10. The UE of claim 9, wherein the MIMO signal comprises an integer number of transmit layers, and wherein the integer number of transmit layers is less than the number of transmit antennas.

11. The UE of claim 9, wherein the at least one processor is configured to enable the UE to apply a set of MPR tables.

12. The UE of claim 11, wherein the set of MPR tables is further based on a receiver algorithm, and wherein the receiver algorithm includes a linear unbiased minimum mean square error (MMSE) receiver or a pseudo-inverse MIMO receiver.

13. The UE of claim 11, wherein the set of MPR tables is further based on the number of transmit layers associated with the MIMO signal.

14. The UE of claim 11, wherein the indication of applying the MPR further includes an indication of which MPR tables in the set of MPR tables will be used for the one or more subsequent transmissions.

15. A method performed by a user equipment (UE), the method comprising: Receive commands to transmit multiple-input multiple-output (MIMO) signals; The MIMO signal is transmitted using multiple transmitting antennas; The system receives an instruction to apply maximum power reduction (MPR), wherein the MPR is based at least in part on the error vector magnitude (EVM) associated with the MIMO signal and the number of transmit antennas of the UE. and Based on the MPR, one or more subsequent transmissions are performed at a certain power level.

16. A base station for wireless communication, comprising: At least one memory; and At least one processor, coupled to and configured to enable the base station to: A set of maximum power reduction (MPR) tables is identified, at least in part, based on the receiver algorithm used by the base station; The MPR table is selected from the set of MPR tables based at least in part on the error vector amplitude (EVM) requirement of the user equipment (UE) and the number of transmit antennas of the UE. Transmit an instruction to the UE to apply the selected MPR table; and Based on the MPR, one or more uplink UL transmissions are received at a certain power level.

17. The base station according to claim 16, wherein the receiver algorithm comprises a linear unbiased minimum mean square error (MMSE) receiver or a pseudo-inverse multiple-input multiple-output (MIMO) receiver.

18. The base station of claim 16, wherein the set of MPR tables is further based on the number of transmission layers associated with the one or more UL transmissions, and wherein the EVM requirement is based at least in part on the receiver algorithm.

19. The base station of claim 16, wherein the at least one processor is configured to enable the base station to further select the MPR table based on EVM measurements associated with the number of transmit antennas of the UE.

20. The base station of claim 16, wherein the selected MPR table corresponds to the number of transmit antennas of the UE and the number of transmit layers associated with the multiple-input multiple-output (MIMO) signal.

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