Communication systems, apparatus, methods, and non-temporary computer-readable storage devices that use stream-based modulation / coding system assignment for multi-input multi-output communication.

Abstract

A first multi-output (MIMO) communication method comprises the steps of generating signaling for one or more devices and transmitting the signaling to one or more devices, wherein for each of the one or more devices, the signaling is for indicating a plurality of streams assigned to the device and a plurality of modulation-coding system (MCS) indices corresponding to each of those streams. Thus, a second MIMO communication method comprises the steps of receiving signaling from a device to obtain a plurality of streams and a plurality of MCS indices corresponding to those streams, and transmitting a signal to the device using the streams with parameters for each stream defined by the corresponding MCS indices. In some embodiments, the signaling is carried in a trigger frame for uplink MIMO communication or in a physical layer protocol data unit for downlink MIMO communication.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the interests of U.S. Provisional Patent Application No. 63 / 533,188, filed on 17 August 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] This disclosure generally relates to communication systems, apparatus, methods, and non-temporary computer-readable storage devices, and more particularly to communication systems, apparatus, methods, and non-temporary computer-readable storage devices that use stream-based modulation and coding system assignment for multi-input multi-output (MIMO) communications, such as uplink multi-user MIMO communications. [Background technology]

[0003] Wireless communication systems such as 802.11ac (Wi-Fi® 5, Wi-Fi is a registered trademark of the Wi-Fi Alliance in Austin, Texas, USA) and 802.11ax (Wi-Fi® 6) systems may utilize multiple antennas on an access point (AP) and / or station (STA) to form multiple spatial streams (or simply "streams") between the AP and the STA for communication between the AP and the STA, employing multi-input multiple-output (MIMO) technology.

[0004] In such a system, the modulation-coding system (MCS, also called the "modulation-coding scheme") defines multiple candidate MCS indices (the set of which is called the MCS table), each MCS index representing a set of modulation-coding parameters such as modulation type, coding rate, number of streams, channel width, and orthogonal frequency division multiplexing (OFDM) guard interval. Therefore, different MCS indices represent different communication performance. The AP and STA can negotiate the MCS index used to establish communication between the AP and STA.

[0005] In uplink (UL) communication from STA to AP, UL Multi-User Multi-Input Multi-Output (MU-MIMO) technology can be used to allow multiple STAs to simultaneously transmit signals to the AP using multiple streams. In prior art, an STA may be assigned a single MCS index regardless of the number of streams allocated to it. Therefore, if an STA is assigned a low-performance MCS index, the STA's communication performance can be significantly reduced. [Overview of the project]

[0006] According to one aspect of the present disclosure, a first multiple-input multiple-output (MIMO) communication method is provided, comprising the steps of generating a signaling for one or more devices and transmitting the signaling to one or more devices, wherein for each of the one or more devices, the signaling is for indicating a plurality of streams assigned to the device and a plurality of modulation and coding system (MCS) indices corresponding to each of the plurality of streams. [Means for solving the problem]

[0007] In some embodiments of the first MIMO communication method, one or more devices are one or more stations (STAs).

[0008] In some embodiments of the first MIMO communication method, the signaling includes a first instruction and a second instruction for each of one or more devices, wherein for each of the one or more devices, the first instruction is for indicating a plurality of streams assigned to the device, and the second instruction is for indicating a plurality of modulation-coding system (MCS) indices corresponding to each of the plurality of streams.

[0009] In some embodiments of the first MIMO communication method, signaling is carried in a trigger frame of uplink (UL) MIMO communication, the trigger frame includes a user information field for each device, and first and second instructions for each device are stored in the corresponding user information fields of the trigger frame.

[0010] In some embodiments of the first MIMO communication method, signaling is carried in the trigger frame of uplink (UL) multi-user MIMO (MU-MIMO) communication or UL single-user MIMO (SU-MIMO) communication.

[0011] In some embodiments of the first MIMO communication method, the first instruction also indicates an MCS table containing multiple MCS sets, each MCS set containing multiple entries representing multiple candidate MCS indices for multiple streams, and the second instruction includes an MCS set index indicating one of the multiple MCS sets.

[0012] In some embodiments of the first MIMO communication method, the MCS table is one of several candidate MCS tables, the several candidate MCS tables include single-stream MCS tables, and each MCS set of the single-stream MCS table includes its respective MCS index, excluding the MCS index in Dup mode.

[0013] In some embodiments of the first MIMO communication method, the multiple candidate MCS indices for each MCS set are in non-ascending or descending order as the index of the multiple streams increases.

[0014] In some embodiments of the first MIMO communication method, the plurality of items of each MCS set are the plurality of candidate MCS indices of the MCS set, and the plurality of items of each MCS set include a base candidate MCS index and one or more index differences from the base candidate MCS index, or the plurality of items of each MCS set include a base candidate MCS index and one or more index differences from its neighboring candidate MCS index.

[0015] In some embodiments of the first MIMO communication method, the second indication includes a plurality of candidate MCS indices.

[0016] In some embodiments of the first MIMO communication method, the first and second indications for each device are stored in the user information field of the trigger frame together with a unique identifier (ID).

[0017] In some embodiments of the first MIMO communication method, the first indication is stored in the spatial stream (SS) allocation / RA-RU information subfield of the user information field, and the second indication is stored in one or more of the UL MCS subfield, the first reserved subfield, the second reserved subfield, and the trigger-dependent user information subfield of the user information field.

[0018] In some embodiments of the first MIMO communication method, the first indication is stored in the last two bits of the SS allocation / RA-RU information subfield of the user information field, and the second indication is stored in the UL MCS subfield of the user information field.

[0019] In some embodiments of the first MIMO communication method, the signaling is carried in the physical layer protocol data unit (PPDU) of the downlink (DL) MIMO communication, and the first and second indications for each device are stored in one or more signal (SIG) fields of the PPDU.

[0020] In some embodiments of the first MIMO communication method, one or more SIG fields of the PPDU include one or more of the L-SIG field, RL-SIG field, U-SIG field, and EHT-SIG field.

[0021] In some embodiments of the first MIMO communication method, one or more SIG fields of the PPDU include an EHT-SIG field, and first and second instructions for each device are stored in one or more user-specific fields of the EHT-SIG field of DL MU-MIMO, or in one or more common fields of the EHT-SIG field of DL SU-MIMO.

[0022] According to one aspect of the present disclosure, one or more circuits are provided, such as at least one processing unit or at least one processor, for performing the first MIMO communication method described above.

[0023] According to one aspect of the present disclosure, one or more non-temporary computer-readable storage devices are provided that include computer-executable instructions, which, when executed, cause one or more circuits, such as at least one processing unit or at least one processor, to execute the first MIMO communication method described above.

[0024] According to one aspect of the present disclosure, a second MIMO communication method is provided, which includes the steps of receiving signaling from a device in order to obtain a plurality of streams and a plurality of MCS indices corresponding to the plurality of streams, and transmitting a plurality of signals to the device using the plurality of streams with parameters for each stream defined by one of the corresponding MCS indices.

[0025] In some embodiments of the second MIMO communication method, the MIMO communication method is performed by STA.

[0026] In some embodiments, the device is an access point (AP).

[0027] In some embodiments of the second MIMO communication method, the signaling includes a first instruction that points to a plurality of streams and a second instruction that points to a plurality of MCS indices.

[0028] In some embodiments of the second MIMO communication method, signaling is carried in the trigger frame of the UL MIMO communication, and the first and second instructions are stored in the user information field of the trigger frame.

[0029] In some embodiments of the second MIMO communication method, signaling is carried in the trigger frame of UL MU-MIMO communication or UL SU-MIMO communication.

[0030] In some embodiments of the second MIMO communication method, the first instruction also indicates an MCS table containing multiple MCS sets, each MCS set containing multiple entries representing multiple candidate MCS indices for multiple streams, and the second instruction includes an MCS set index indicating one of the multiple MCS sets.

[0031] In some embodiments of the second MIMO communication method, the MCS table is one of several candidate MCS tables, the several candidate MCS tables include single-stream MCS tables, and each MCS set of the single-stream MCS table includes its respective MCS index, excluding the MCS index in Dup mode.

[0032] In some embodiments of the second MIMO communication method, the multiple candidate MCS indices for each MCS set are in non-ascending or descending order as the index of the multiple streams increases.

[0033] In some embodiments of the second MIMO communication method, each MCS set has multiple items that are multiple candidate MCS indices of the MCS set, each MCS set has multiple items that include a base candidate MCS index and one or more index differences from the base candidate MCS index, or each MCS set has multiple items that include a base candidate MCS index and one or more index differences from its neighbor candidate MCS indices.

[0034] In some embodiments of the second MIMO communication method, the second instruction includes a plurality of candidate MCS indices.

[0035] In some embodiments of the second MIMO communication method, the first and second instructions for each device are stored in the user information field of the trigger frame along with a unique ID.

[0036] In some embodiments of the second MIMO communication method, the first instruction is stored in the SS assignment / RA-RU information subfield of the user information field, and the second instruction is stored in one or more of the UL MCS subfield, the first reservation subfield, the second reservation subfield, and the trigger-dependent user information subfield of the user information field.

[0037] In some embodiments of the second MIMO communication method, the first instruction is stored in the last two bits of the SS assignment / RA-RU information subfield of the user information field, and the second instruction is stored in the UL MCS subfield of the user information field.

[0038] In some embodiments of the second MIMO communication method, signaling is carried in the PPDU of the DL MIMO communication, and the first and second instructions are stored in one or more SIG fields of the PPDU.

[0039] In some embodiments of the second MIMO communication method, one or more SIG fields of the PPDU include one or more of the L-SIG field, RL-SIG field, U-SIG field, and EHT-SIG field.

[0040] In some embodiments of the second MIMO communication method, one or more SIG fields of the PPDU include an EHT-SIG field, and first and second instructions for each device are stored in one or more user-specific fields of the EHT-SIG field of DL MU-MIMO, or in one or more common fields of the EHT-SIG field of DL SU-MIMO.

[0041] In some embodiments of the second MIMO communication method, signals transmitted in each stream are encoded and / or interleaved independently of signals transmitted in other streams.

[0042] According to one aspect of the present disclosure, one or more circuits are provided, such as at least one processing unit or at least one processor, for performing the second MIMO communication method described above.

[0043] According to one aspect of the present disclosure, one or more non-temporary computer-readable storage devices are provided that include computer-executable instructions, which, when executed, cause one or more circuits, such as at least one processing unit or at least one processor, to execute the second MIMO communication method described above.

[0044] The first and second MIMO communication methods described above enable the AP and STA to communicate with each other over multiple streams using communication parameters (represented by the MCS index) that are adapted to the characteristics of the streams for better stream operation, compared to conventional methods in which the STA must adapt to the worst-case stream among those assigned, wasting the capacity of other, better-performing streams. As a result, the communication performance achieved by the stream-based MCS assignment and instruction methods disclosed herein is improved. [Brief explanation of the drawing]

[0045] [Figure 1] This is a simplified schematic diagram illustrating a communication system according to some embodiments of the present disclosure. [Figure 2] Figure 1 is a simplified schematic diagram of the access points (APs) in the communication network of the communication system shown. [Figure 3] Figure 1 is a simplified schematic diagram of a communication system station (STA). [Figure 4] Figure 1 is a schematic diagram showing the uplink (UL) multi-user multiple input multiple output (MU-MIMO) of the communication system. [Figure 5] This plot shows the UL MU-MIMO packet error rate (PER) performance of three scheduled STAs using the prior art MCS allocation method. [Figure 6] This is a schematic diagram showing the structure of a trigger frame transmitted from an AP to multiple STAs in a communication system shown in Figure 1, according to some embodiments of the present disclosure. [Figure 7] This is a schematic diagram showing the structure of the user information field in the trigger frame shown in Figure 6, according to some embodiments of the present disclosure. [Figure 8]This flowchart shows the notification procedure performed by the AP of the communication system shown in Figure 1 to notify multiple STAs regarding an assigned stream and the corresponding MCS index, according to some embodiments of the present disclosure. [Figure 9] This flowchart shows the steps performed by the STA of the communication system shown in Figure 1 to establish UL communication with the AP using an allocated stream, according to some embodiments of the present disclosure. [Figure 10] Figure 1 shows a plot comparing the PER (Percentage-to-Efficiency) ratio of the MCS method per stream shown in Figures 8 and 9 with the conventional MCS method per STA for UL MU-MIMO from three (3) STAs to APs in the communication system shown in Figure 1, with each STA assigned two streams. [Figure 11] Figure 1 shows a plot comparing the goodput of the UL MU-MIMO from three (3) STAs to APs in the communication system shown in Figures 8 and 9 with the conventional STA-based MCS method, where each STA is assigned two streams. [Figure 12] Figure 1 is a schematic diagram showing the structure of an ultra-high-throughput (EHT) physical layer protocol data unit (PPDU) transmitted from an AP to multiple STAs in a communication system shown in some embodiments of the present disclosure. [Modes for carrying out the invention]

[0046] Embodiments disclosed herein relate to wireless systems, apparatus, and methods, communication systems, apparatus, and methods, and non-temporary computer-readable storage devices that apply stream-based modulation and coding system assignment to uplink multi-user multi-input multi-output (MU-MIMO) communication. The wireless systems, apparatus, and methods disclosed herein may be any suitable systems, apparatus, and methods for transmitting wireless signals. Examples of such systems may include Wi-Fi® systems, 5G or 6G wireless mobile communication systems, etc.

[0047] A. System Structure Referring here to Figure 1, a communication system according to several embodiments of the present disclosure is shown, collectively identified by reference no. 100. As an example, the communication system 100 may be a Wi-Fi® system built under relevant standards such as the IEEE 802.11 standard. As illustrated, the communication system 100 comprises multiple interconnected networking devices 102, including multiple interconnected access points (APs, also called "base stations") that form a distribution system (DS) 104, the distribution system may include a network and / or subnet (intranet) of computers and connect to other networks such as the Internet 108, which can incorporate protocols such as the Internet Protocol (IP), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP).

[0048] Each AP 102 wirelessly communicates with one or more mobile or stationary stations 112 (STAs) through its respective radio channel 114 to provide wireless network connectivity to the stations 112. Here, the APs 102 and STAs 112 can be thought of as different types of network nodes (or simply “nodes”) of the communication system 100. Each AP 102 and the STA 112 connected to it form a cell or basic service set (BSS) 118.

[0049] Figure 2 is a simplified schematic diagram of AP 102. As shown, AP 102 comprises at least one processing unit 142 (also referred to as at least one “processor”), at least one transmitter (TX) 144, at least one receiver (RX) 146 (collectively referred to as transceivers), one or more antennas 148, at least one memory 150, and one or more input / output components or interfaces 152. A scheduler 154 may be coupled to the processing unit 142. The scheduler 154 may be contained within AP 102 or operated separately from AP 102. Each of these components 142-154 may be implemented as one or more circuits (such as one or more electronic circuits and / or one or more optical circuits). Alternatively, the set of these components 142-154 may be implemented as one or more circuits.

[0050] The processing unit 142 is configured to perform a variety of processing tasks, such as signal coding, data processing, power control, input / output processing, or any other suitable function. The processing unit 142 may include a microprocessor, microcontroller, digital signal processor, FPGA, ASIC, etc. In some embodiments, the processing unit 142 can execute computer executable instructions or code stored in memory 150 to perform various procedures (also called methods) described below.

[0051] Each transmitter 144 may have any suitable configuration for generating signals, such as control signals as described in detail below, for radio transmission to one or more STAs 112. Each receiver 146 may have any suitable configuration for processing signals received radio from one or more STAs 112. Although shown as separate components, at least one transmitter 144 and at least one receiver 146 may be integrated and implemented as a transceiver. Each antenna 148 may have any suitable configuration for transmitting and / or receiving radio signals. In Figure 2, a common antenna 148 is shown coupled to both the transmitter 144 and the receiver 146, but one or more antennas 148 may be coupled to the transmitter 144, and one or more other antennas 148 may be coupled to the receiver 146.

[0052] In some embodiments, AP 102 may be equipped with multiple transmitters 144 and receivers 146 (or multiple transceivers) along with multiple antennas 148 for communication within its cell 118.

[0053] Each memory 150 may be equipped with any suitable volatile and / or non-volatile storage, such as RAM, ROM, hard disk, optical disk, SIM card, solid-state memory, memory stick, or SD memory card. The memory 150 may be used to store instructions that can be executed by the processing unit 142, and data that is used, generated, or collected by the processing unit 142. For example, the memory 150 can store instructions for software, a software system, or a software module that can be executed by the processing unit 142 to perform some or all of the functions and / or embodiments of the procedures performed by the AP 102 described herein.

[0054] Each input / output component 152 enables interaction with a user or other devices within the communication system 100. Each input / output device 152 may have any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, touchscreen, or network communication interface.

[0055] Here, STA 112 may be any suitable wireless device that can participate in the communication system 100 via AP 102 for wireless work. In various embodiments, STA 112 may be a wireless electronic device used by a person or user (such as a smartphone, mobile phone, personal digital assistant (PDA), laptop, desktop computer, tablet, smartwatch, or home appliance). Alternatively, STA 112 may be a wireless sensor, Internet of Things (IoT) device, robot, shopping cart, vehicle, smart TV, smart appliance, wireless transceiver unit (WTRU), mobile station, etc. Depending on the implementation, STA 112 may be mobile autonomously or under direct or remote human control, or it may be stationary.

[0056] In some embodiments, the STA 112 may be a multimode radio electronic device capable of operating according to multiple radio access technologies and may incorporate multiple transceivers necessary to support such technologies.

[0057] In addition, some or all of the STA 112s are equipped with the capability to communicate with various wireless devices and / or wireless networks via various wireless links using various wireless technologies and / or protocols. Instead of (or in addition to) wireless communication, the STA 112s may communicate with other devices or switches (not shown) and the Internet 106 via wired communication channels. For example, multiple STA 112s (such as STA 112s in close proximity to each other) may communicate directly with each other via appropriate wired or wireless sidelinks.

[0058] Figure 3 is a simplified schematic diagram of the STA 112. As shown, the STA 112 comprises at least one processing unit 202, at least one transceiver 204, at least one antenna or network interface controller (NIC) 206, at least one positioning module 208, one or more input / output components 210, at least one memory 212, and at least one other communication component 214. Each of these components 202-214 may be implemented as one or more circuits (such as one or more electronic circuits and / or one or more optical circuits). Alternatively, the set of these components 202-214 may be implemented as one or more circuits.

[0059] The processing unit 202 is configured to perform various processing tasks, such as signal coding, data processing, power control, input / output processing, or any other functions, in order to enable the STA 112 to access and participate in the communication system 100 and to operate on the communication system. The processing unit 202 may also be configured to perform some or all of the functions of the STA 112 described herein. The processing unit 202 may comprise a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor, an accelerator, a graphics processing unit (GPU), a tensor processing unit (TPU), an FPGA, or an ASIC. Examples of processing unit 202 may include ARM® microprocessors (ARM is a registered trademark of Arm Ltd., Cambridge, UK), INTEL® microprocessors (INTEL is a registered trademark of Intel Corp., Santa Clara, California, USA), and AMD® microprocessors (AMD is a registered trademark of Advanced Micro Devices Inc., Sunnyvale, California, USA), manufactured by various manufacturers such as Qualcomm, San Diego, California, USA, under the ARM® architecture. In some embodiments, processing unit 202 can execute computer executable instructions or code stored in memory 212 to perform various processes described below.

[0060] At least one transceiver 204 may be configured to modulate data or other content for transmission by at least one antenna 206 in order to communicate with AP 102. Transceiver 204 is also configured to demodulate data or other content received by at least one antenna 206. Each transceiver 204 may have any suitable structure for generating a signal for radio transmission and / or processing a signal received radio. Each antenna 206 may have any suitable structure for transmitting and / or receiving radio signals. Although shown as a single functional unit, the transceivers 204 may be implemented separately as at least one transmitter and at least one receiver.

[0061] The positioning module 208 is configured to communicate with multiple global or regional positioning devices, such as navigation satellites, to determine the position of STA 112. The navigation satellites may be satellites of a Global Navigation Satellite System (GNSS), such as the US Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), the European Union's Galileo Positioning System, and / or China's Beidou System. The navigation satellites may also be satellites of a Regional Navigation Satellite System (RNSS), such as India's Regional Navigation Satellite System (IRNSS) or Japan's Quasi-Zenith Satellite System (QZSS). In some other embodiments, the positioning module 208 may be configured to communicate with multiple indoor positioning devices to determine the position of STA 112.

[0062] One or more input / output components 210 are configured to interact with a user or other device within the communication system 100. Each input / output component 210 may have any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touchscreen.

[0063] At least one memory 212 is configured to store instructions executable by the processing unit 202 and data used, generated, or collected by the processing unit 202. For example, memory 212 can store instructions for software, software systems, or software modules executable by the processing unit 202 to carry out some or all of the functions and / or embodiments of STA 112 described herein. Each memory 212 may include any suitable volatile and / or non-volatile storage and retrieval components such as RAM, ROM, hard disk, optical disk, SIM card, solid-state memory module, memory stick, or SD memory card.

[0064] At least one other communication component 214 is configured to communicate with other devices such as other STA 112s by other means of communication, such as a wireless link, a BLUETOOTH® link (BLUETOOTH is a registered trademark of Bluetooth Sig Inc., Kirkland, Washington, USA), or a wired sidelink. Examples of wired sidelinks may include USB cables, network cables, parallel cables, and / or serial cables.

[0065] In some embodiments, the STA 112 may include multiple transceivers 204 and multiple antennas 206 for communication with the AP 102.

[0066] In communication between AP 102 and STA 112, transmission from STA 112 to AP 102 is typically referred to as uplink (UL), and the radio channel used for this is referred to as the uplink channel. Transmission from AP 102 to STA 112 is typically referred to as downlink (DL), and the radio channel used for this is referred to as the downlink channel. Appropriate modulation techniques may be used for communication between AP 102 and STA 112. For example, in some embodiments, orthogonal frequency division multiplexing (OFDM) may be used, in which case channel 114 is divided into multiple orthogonal subchannels for communication between AP 102 and STA 112. Furthermore, since there are usually multiple STA 112s communicating with the same AP 102, appropriate multiple access techniques may be used. For example, in some embodiments, orthogonal frequency division multiple access (OFDMA) may be used for communication between AP 102 and STA 112.

[0067] B. MCS Assignment and Instructions By using multiple antennas on the AP side and / or STA side, AP 102 and STA 112 can use multiple-input multiple-output (MIMO) technology for communication between AP 102 and STA 112, and such a system 100 may be referred to as a “MIMO system”. More specifically, MIMO technology may be used for communication between AP 102 and a single STA 112 (referred to as “SU-MIMO”), or for communication between AP 102 and multiple STA 112 (referred to as “MU-MIMO”). Furthermore, SU-MIMO can be further classified into DL SU-MIMO (in the case of DL communication, i.e., AP 102 transmits signals to a single STA 112) and UL SU-MIMO (in the case of UL communication, i.e., a single STA 112 transmits signals to AP 102). Similarly, MU-MIMO can be further classified into DL MU-MIMO (in the case of DL communication, i.e., AP 102 transmits signals to multiple STA 112s) and UL MU-MIMO (in the case of UL communication, i.e., multiple STA 112s transmit signals to AP 102 simultaneously). For example, the 802.11ax standard (Wi-Fi® 6) may use UL MU-MIMO.

[0068] Figure 4 is a schematic diagram showing an example of a communication system 100 using UL MU-MIMO. For ease of illustration, Figure 4 shows only one AP 102 (also referred to as "AP-1") and N STAs 112 (also referred to as "STA-1", "STA-2", ..., "STA-N"). AP 102 has N1 antennas 148 (which may receive signals in UL communication, and are referred to as "TX antennas TX-1 to TX-N1"), and the nth STA (STA-n) is M n These 206 antennas (which sometimes transmit signals via UL communication, are referred to as "RX Antenna RX-1~RX-M") n It is equipped with (which is referred to as "...").

[0069] In this example, AP 102 can typically have up to eight TX antennas 148, while each STA 112 is limited by the number of RX antennas 206. Multiple STAs 112 can simultaneously transmit their UL data packets in separate spatial streams (or simply "streams") over a radio channel, which is called UL MU-MIMO.

[0070] STA-n is M n Having 206 RX antennas, the maximum number of streams for UL data packet transmission from STA-n to AP 102 is K. n M n The following applies: Since the number of TX antennas 148 in AP-1 is N1, the total number of streams (i.e., from K1 to K) N The sum up to is less than or equal to N1.

[0071] The eigenvalues ​​of a UL stream (represented by the singular values ​​of the diagonal matrix after singular value decomposition (SVD) of the channel matrix) are in descending order from the first stream (corresponding to the upper singular value of the diagonal matrix) to the last stream (corresponding to the lower singular value of the diagonal matrix), similar to DL MIMO channels. All streams in UL MU-MIMO transmission.

number

number

[0072] In prior art, the same MCS may be assigned to each UL MU-MIMO scheduled STA, regardless of the number of streams assigned to each scheduled STA. Therefore, the worst MCS for the streams assigned to each scheduled STA is distributed across all assigned streams of the scheduled STA. This can impair the mean packet error rate (PER) performance of each scheduled STA.

[0073] Figure 5 is a plot showing the PER performance of UL repeat beamforming and UL MU-MIMO without UL beamforming for three scheduled STA 112s (STA0, STA1, and STA2) using the prior art MCS allocation method, with each STA 112 allocated two streams. In the legend of Figure 5, "ITULBF" refers to UL repeat beamforming, "ULw / oBF" refers to UL MU-MIMO without UL beamforming, and "pXq" refers to p TX antennas and q RX antennas (for example, 6X8 refers to 6 TX antennas and 8 RX antennas).

[0074] As illustrated, for each MCS (MCS1, MCS3, or MCS7), STA0 shows the best performance, followed by STA1 and STA2. When the two streams of each STA are averaged, these three STAs still show an SNR gap for the same PER, with STA0 assigned to the first two streams, STA1 to the next two streams, and STA2 to the last two streams. For the same PER, STA0 has the best SNR range, followed by STA1 and STA2.

[0075] In some embodiments, the communication system 100 can assign an MCS index to each UL stream of each UL-scheduled STA 112 using a stream-based MCS assignment method. Thus, an STA 112 to which multiple UL streams are assigned may be assigned multiple MCS indices, and the assigned MCS indices may have different index values, or some of the assigned MCS indices may have the same index value. Such a stream-based MCS assignment method can significantly reduce the possibility of a decrease in the communication performance of the STA due to a "bad" MCS assignment.

[0076] Various embodiments are described below, in which an appropriate signaling method can be used to instruct each MCS index to be assigned to each stream of each scheduled STA 112. In this specification, the term “signaling” refers to the use of specific signals to control communication, and the term “signal” generally refers to information transmitted between devices, such as between AP 102 and one or more STA 112.

[0077] More specifically, signaling may be sent from a first device (such as an AP 102) to one or more second devices (such as one or more STA 112s) to indicate the respective MCS index assigned to each stream of the scheduled STA 112. Each STA 112 receives the signaling sent from the AP 102 and obtains multiple assigned streams and multiple MCS indices corresponding to the multiple assigned streams, and then uses the multiple assigned streams to send multiple signals to the device, according to the parameters of each assigned stream defined by the corresponding MCS index.

[0078] In some embodiments, signaling may be carried in a trigger frame in UL MIMO communications such as UL MU-MIMO and / or UL SU-MIMO. In some embodiments, signaling may be carried in a Physical Layer Protocol Data Unit (PPDU) in DL MIMO communications such as DL MU-MIMO and / or DL ​​SU-MIMO.

[0079] The MCS assignment and instruction methods disclosed herein can be used in a variety of systems, including WI-FI® 8, while providing backward compatibility with "older" standards such as WI-FI® 6 (IEEE 802.11ax, also known as "High Efficiency (HE)") and WI-FI® 7 (IEEE 802.11be, also known as "Ultra High Throughput (EHT)").

[0080] As those skilled in the art will understand, in a Wi-Fi® system, AP 102 can send a trigger frame to STA 112 to notify STA 112 of information (e.g., scheduling information) or to request information from STA 112. In prior art such as Wi-Fi® 6 and Wi-Fi® 7, the trigger frame indicates the MCS index assigned to the UL MU-MIMO scheduled STA 112.

[0081] In some embodiments, trigger frames may be used to instruct stream-based MCS allocation.

[0082] Figure 6 shows the structure of the irregularly shaped trigger frame 300 in these embodiments. As shown in the figure, the trigger frame 300 is • A frame control field 302 of two octets (i.e., 16 bits, where one octet is equal to eight bits), • 2(2) Octet duration field 304, • The 6th octet's Receiving STA Address (RA) field 306 (indicates the address of the STA to which the trigger frame 300 is sent, such as the broadcast address of the Receiving STA, referred to as the "Receiving STA"), • Six (6) octets of the transmitting AP address (TA) field 308, • 8 (octets) or more common information field 310, • Variable-length user information list field 312, • Variable length padding field 314, and • Includes a four-octet frame check sequence (FCS) field 316.

[0083] The set of frame control field 302, duration field 304, RA field 306, and TA field 308 is sometimes referred to as the media access control (MAC) header.

[0084] The user information list field 312 includes one or more user information fields (identified as 312') for one or more receiving STAs 112, where each user information field 312' includes details of the corresponding receiving STA 112.

[0085] Figure 7 shows details of the user information field 312'. As shown in the figure, the user information field 312' is • 12-bit association identifier (AID) subfield 342 (bits 0 (B0) to 11 (B11)) to indicate the identifier of the receiving STA, • 8-bit Resource Unit (RU) allocation subfield 344 (B12 to B19) to indicate the RU assigned to the receiving STA, • 1-bit UL forward error correction (FEC) encoding type subfield 346 (B20), • 4-bit UL Ultra High Reliability (UHR) MCS subfield 348 (B21 to B24) • The first 1-bit reserved subfield 350 (B25) (which may be used to indicate UL dual-carrier modulation (DCM)), • 6-bit spatial stream (SS) allocation / RA-RU information subfield 352 (B26~B31) • 7-bit UL target received power subfield 354 (UL target received signal strength indicator (RSSI) subfield, etc.) (B32 to B38) • Second 1-bit reserved subfield 356 (B39), and • Includes a variable-length trigger-dependent user information subfield 358.

[0086] In prior art such as Wi-Fi® 6 and Wi-Fi® 7, a 4-bit UL MCS subfield (corresponding to the UL UHR MCS subfield 348 in these embodiments) is used to indicate the MCS index assigned to the receiving STA. In HE, the 6-bit SS assignment / RA-RU information subfield 352 includes three bits to indicate the number of streams assigned to the receiving STA (more specifically, equal to the number of assigned streams plus one) and three bits to indicate the starting stream of the assigned streams. In EHT, the first four bits of the SS assignment / RA-RU information subfield 352 are used to indicate the starting stream of the assigned streams, and the last two bits are used to indicate the number of assigned streams.

[0087] In these embodiments, the 4-bit UL MCS subfield 348 and the 6-bit SS allocation / RA-RU information subfield 352 are used to indicate one or more MCS indexes corresponding to one or more streams assigned to the receiving STA.

[0088] More specifically, in these embodiments, L MCS tables (where L>1 is a predefined integer) may be predefined and known to both the AP 102 and the STA 112 scheduled for UL MU-MIMO transmission. The l-th MCS table (where L≧l≧1) defines a plurality of MCS index sets (also simply referred to as "MCS sets") for the l streams assigned to each STA 112, and each MCS set includes l predefined candidate MCS indexes for the l streams in non-increasing order from the first stream to the last stream among the l streams. The L MCS tables may or may not have the same number of MCS sets.

[0089] When the AP 102 assigns a stream to the STA 112, the AP 102 first determines the number of streams (e.g., i streams, where L≧i≧1). Then, the AP 102 determines the MCS set index j from the i-th MCS table and uses the UL MCS subfield 348 and the SS allocation / RA-RU information subfield 352 to transmit j and i to the STA 112, respectively. Here, i indicates the MCS table corresponding to the number of streams assigned to the STA 112, which requires log2L bits to store in the trigger frame, and j indicates the MCS index of the stream assigned to the STA 112, which requires log2L M bits to store in the trigger frame, and L M is the maximum number of rows of the L MCS tables (i.e., the maximum number of MCS sets among the L MCS tables).

[0090] For example, in some embodiments, four (4) MCS tables, including the following four MCS tables, are predefined and known to both AP 102 and STA 112 (i.e., L=4), L M The value is 15 (i.e., the first MCS table has the largest number of MCS sets among the four MCS tables).

[0091] The first MCS table (Table 1) contains base UHR MCS indexes 0 through 13 and 15, excluding the Dup mode (EHT-MCS 14) for one assigned stream. The second, third, and fourth MCS tables (Tables 2 through 4) each contain 10 MCS sets, each having 2, 3, and 4 MCS indexes in non-ascending order from the first assigned stream to the last assigned stream, i.e., if p > q, the MCS index of the p-th assigned stream is greater than or equal to the MCS index of the q-th assigned stream. Furthermore, in each MCS table, the MCS set index can be any suitable index, for example, starting from zero (0) but not necessarily increasing by one (1) (Table 1, MCS set index skips 14), or starting from one (1) and increasing by one (1) (Tables 2 through 4).

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4]

[0096] In this example, four MCS tables are used (i.e., 4 ≥ i ≥ 1), and therefore two bits are needed to indicate i. Of the four MCS tables, the maximum number of MCS index sets is 16 (i.e., 16 ≥ j ≥ 1), and therefore four bits are needed to indicate j. Thus, in this example, the last two bits B30 and B31 of the SS allocation / RA-RU information subfield 352 may be used to store i (indicating the number of streams allocated to STA 112 and the corresponding MCS table), and the four-bit UL MCS subfield 348 may be used to store j (indicating the MCS index of the allocated stream).

[0097] In some embodiments, the encoding of each stream (e.g., each UL stream) is multicodeword-based. In other words, the signals transmitted in each stream are encoded and / or interleaved independently of the signals transmitted in other streams. Multicodeword-based encoding and interleaving may also be required when different MCS indices are assigned to each stream in DL SU / MU-MIMO transmissions.

[0098] In some embodiments, a combination of a 4-bit UL MCS subfield 348 and two 1-bit reserved subfields 350 and 356 (i.e., six bits of B21-B25 and B39) may be used to indicate the MCS index assigned to the receiving STA 112, thereby allowing each MCS table to have up to 64 combinations.

[0099] In some embodiments, more bits in the trigger frame 300 may be used to indicate the MCS index assigned to the receiving STA 112, thereby allowing each MCS table to have more combinations. For example, in some embodiments, bits B21-B25 and B39 (i.e., UL MCS subfield 348 and the two reserved subfields 350 and 356) and one or more bits in the trigger-dependent user information subfield 358 may be used to indicate the MCS index assigned to the receiving STA 112.

[0100] In some embodiments, one or more of the UL MCS subfield 348, reserved subfield 350, and reserved subfield 356 may be used to indicate the MCS index assigned to the receiving STA 112.

[0101] In some embodiments, one or more of the UL MCS subfield 348, reserved subfield 350, and reserved subfield 356 may be combined with one or more bits in the trigger-dependent user information subfield 358 to indicate the MCS index assigned to the receiving STA 112.

[0102] In some embodiments, the UL MCS subfield 348 and the two reserved subfields 350 and 356 may not be used to indicate the MCS index assigned to the receiving STA 112. Rather, one or more bits in the trigger-dependent user information subfield 358 may be used to indicate the MCS index assigned to the receiving STA 112. In these embodiments, it may be preferable to introduce a new type of trigger frame 300 (e.g., referred to as the "UHR basic trigger frame") and define the required information (such as sub-subfields) in the trigger-dependent user information subfield 358.

[0103] In the embodiments described above, in the MCS tables of multiple streams (such as Tables 2 to 4 above), each MCS set includes the MCS index of multiple streams. In some embodiments, in the MCS tables of multiple streams, each MCS set includes the k of one predefined stream (such as the first stream) among the multiple streams. b Bit MCS index (referred to as "base MCS index") B And, k from each of the base MCS indices of the other streams among the multiple streams d It may include the bit index difference D, k b 0 ≤ k d ≤ and the MCS index of that stream is (I B It can be obtained as -D). See Tables 5-7. Note that the index difference D of different streams and / or different MCS sets may or may not be the same value.

[0104] [Table 5]

[0105] [Table 6]

[0106] [Table 7]

[0107] In some embodiments, in an MCS table of multiple streams, each MCS set is a predefined base stream among the multiple streams, k b Bit Base MCS Index I B And, for each of the other streams among the multiple streams, k from the predefined neighbor MCS index. d It may include the bit index difference D, k b 0 ≤ k dIt is ≤.

[0108] For example, as shown in Tables 8 to 10, in an MCS table for multiple streams, the first stream is predefined as the base stream. Each MCS set is the k of the first stream. b Bit Base MCS Index I B And, for each of the other streams among the multiple streams, k from the previous MCS index. d The bit index difference D includes k b 0 ≤ k d It is ≤.

[0109] [Table 8]

[0110] [Table 9]

[0111] [Table 10]

[0112] In some embodiments, an MCS table is not used. In these embodiments, the trigger frame 300 includes multiple MCS indexes for the corresponding assigned streams. For example, the trigger frame 300 may include four bits for the MCS index of the first stream, four bits for the MCS of the second stream, four bits for the MCS of the third stream, and four bits for the MCS of the fourth stream. Thus, a total of 16 bits of UL-MCS subfields may be required to indicate all MCS index combinations for up to four UL streams. The MCS indexes may be included in the trigger frame as multiple subfields within each user information field 312', or as multiple sub-subfields within, for example, a trigger-dependent user information subfield 358.

[0113] In the embodiments described above, the MCS table is defined for each STA using a number of consecutive streams (i.e., one assigned stream, two assigned streams, ..., L assigned streams). In some embodiments, the MCS table is defined for each STA using any appropriate number of streams, which does not necessarily start with one assigned stream and / or is not necessarily a number of consecutive streams. For example, in one embodiment, the MCS table is defined for each STA using one assigned stream, two assigned streams, and four assigned streams (L=3). In another example, the MCS table is defined for each STA using two assigned streams, three assigned streams, and four assigned streams (L=3).

[0114] In the example above, the last two bits B30 and B31 of the SS allocation / RA-RU information subfield 352 may be used to store i (indicating the number of streams allocated to STA 112 and the corresponding MCS table). In some other embodiments, other bits of the SS allocation / RA-RU information subfield 352 may be used to store i (indicating the number of streams allocated to STA 112 and the corresponding MCS table).

[0115] Figure 8 is a flowchart of a notification procedure 400 performed by AP 102 (or more specifically, at least one processing unit 142 of AP 102) to notify multiple STAs 112 about their assigned streams and corresponding MCS indices. After procedure 400 is initiated (step 402), AP 102 generates a trigger frame 300 having instructions for multiple streams assigned to each of the STAs 112 and instructions for their corresponding MCS indices (step 404). As described above, the trigger frame 300 includes a user information field 312' for each STA 112, identified by the unique AID 12 subfield 342 of the STA 112. In the user information field 312' of each STA 112, the last two bits of the SS assignment / RA-RU information subfield 352 are used to indicate the number of streams assigned to the STA 112 and the corresponding MCS table, and the 4-bit UL MCS subfield 348 (and / or other subfields / sub-subfields as described above) are used to store j (which indicates the MCS index of the assigned stream).

[0116] In step 406, AP 102 sends trigger frames to multiple STA 112s. After that, notification procedure 400 ends (step 408).

[0117] Figure 9 is a flowchart of the procedure 440 performed by STA 112 to establish UL communication with AP 102 using assigned streams. After procedure 440 is initiated (step 442), STA 112 receives the trigger frame 300 sent from AP 102 as described above and obtains the multiple assigned streams and their corresponding MCS indices (step 444). More specifically, STA 112 identifies the STA 112's user information field 312' of the trigger frame 300 using STA 112's unique AID 12, and then obtains the MCS table number (and therefore the number of streams assigned to STA 112) from the last two bits of the SS assignment / RA-RU information subfield 352. The MCS table to be used is then determined. STA 112 also retrieves the MCS set index from the 4-bit UL MCS subfield 348 (and / or other subfields / sub-subfields as described above). Next, STA retrieves the MCS index from the determined MCS table (stored in STA's memory).

[0118] As those skilled in the art will understand, each MCS index represents a set of communication parameters. In step 446, STA 112 transmits a signal to AP 102 using the assigned stream, with the parameters of each stream defined by the corresponding MCS index. Then, step 440 ends (step 448).

[0119] Figures 10 and 11 are plots showing some simulation results obtained using the following simulation settings: • 6X8 UL MU-MIMO (AP with eight antennas, three STAs scheduled for UL MU-MIMO, each STA assigned two streams (therefore, a total of six streams)), IEEE High Throughput Task Group (TGn) Channel Model D for UL • MCS index per stream: -STA 0:MCS7-MCS5, STA1:MCS5-MCS3, STA2:MCS3-MCS1; • MCS per STA: -STA 0:MCS5-MCS5, STA1:MCS3-MCS3, STA2:MCS1-MCS1 o Aligned with the worst MCS • Goodput (bps / Hz) = (1-PER)(N_BPSC_A*Coderate_A+N_BPSC_B*Coderate_B)*N sc / OFDM symbol length (no guard interval) / BW -N_BPSC_A: Number of bits per subcarrier in the first stream -N_BPSC_B: Number of bits per subcarrier in the second stream -Coderate_A: Code rate of the first stream -Coderate_B: Code rate of the second stream -N sc : Total number of data subcarriers -BW: Bandwidth Least Mean Squares Error (MMSE) detection is used.

[0120] Figure 10 is a plot showing a comparison of the PER between the MCS per stream and the MCS per STA for UL MU-MIMO from three (3) STAs, each having two streams.

[0121] Figure 11 is a plot showing a goodput comparison between the MCS per stream and the MCS per STA for UL MU-MIMO from three (3) STAs, each having two streams.

[0122] In the embodiments described above, a stream-based MCS allocation method is used to assign or otherwise allocate an MCS index to each UL stream of the STA 112. In some embodiments, a trigger frame 300 is used to notify the STA of the assigned UL streams and their corresponding MCS indexes. In some embodiments, the notification or instruction of the assigned streams and their corresponding MCS indexes is embedded in the user information field 312' for each STA 112. In some embodiments, a plurality of predefined MCS tables, each containing a plurality of MCS sets, are used. The number of assigned streams (and therefore the MCS table number) is stored in the SS allocation / RA-RU information subfield 352 of the STA's user information field 312', and the MCS set index is stored in the UL MCS subfield 348 and / or other locations in the STA's user information field 312' (reserved subfield 350, reserved subfield 356, and / or trigger-dependent user information subfield 358).

[0123] In some embodiments, the encoding of each UL stream is multicodeword-based. In other words, signals transmitted in each stream are encoded and / or interleaved independently of signals transmitted in other streams.

[0124] In some embodiments, the MCS indices within the MCS set are in descending order as the stream index increases.

[0125] In the embodiments described above, a stream-based MCS assignment and instruction method is used for UL MU-MIMO. In some embodiments, a stream-based MCS assignment and instruction method may be used for UL SU-MIMO.

[0126] In some embodiments, a stream-based MCS allocation and instruction method may be used for DL ​​SU-MIMO and / or DL ​​MU-MIMO, and the above-described instruction for the number of allocated streams and the MCS index may be stored in the PPDU's signal (SIG) field (such as the U-SIG or EHT-SIG field).

[0127] For example, as shown in Figure 12, the EHT PPDU 500 includes the following fields: L-STF Field 502 (Non-HT Short Training Field) L-LTF Field 504 (Non-HT Long Training Field) • L-SIG field 506 (non-HT signal field) • RL-SIG field 508 (repeating non-HT signal field) • U-SIG Field 510 (Universal Signal Field) • EHT-SIG field 512 (EHT signal field) • EHT-STF Field 514 (EHT Short Training Field) • EHT-LTF Field 516 (EHT Long Training Field) • EHT-Data Field 518 (Data field for carrying PSDU), and • PE field 520 (packet extension field).

[0128] In the case of MU PPDU, the EHT-SIG field 512 includes common fields and several user-specific fields. In the case of SU PPDU, the EHT-SIG field 512 includes common fields but does not include user-specific fields.

[0129] Therefore, in some embodiments, the above-described instructions for the number of allocated streams and the MCS index may be stored in a user-specific field of the EHT-SIG field 512 of the PPDU 500 (e.g., for DL ​​MU-MIMO) and / or in a common field of the EHT-SIG field 512 of the PPDU 500 (e.g., for DL ​​SU-MIMO).

[0130] In some embodiments, any suitable SIG field or a suitable combination of SIG fields of a PPDU (such as the aforementioned PPDU 500 or other types of PPDU) may be used to store the aforementioned instructions for the number of allocated streams and the MCS index for DL ​​SU-MIMO and / or DL ​​MU-MIMO.

[0131] In these embodiments, multi-codeword-based encoding and interleaving may be required even when an MCS index is assigned to each stream in DL SU / MU-MIMO transmission.

[0132] The stream-based MCS assignment and instruction method disclosed herein enables APs and STAs to communicate with each other on multiple streams using communication parameters (represented by MCS indices) that are adapted to the characteristics of the streams for better stream operation, compared to conventional methods in which the STA must adapt to the worst-case stream among the assigned streams, wasting the capacity of other, better-performing streams. As a result, the communication performance achieved by the stream-based MCS assignment and instruction method disclosed herein is improved.

[0133] [Table 11]

[0134] While embodiments have been described above with reference to the attached drawings, those skilled in the art will understand that changes and modifications can be made without departing from the scope defined by the attached claims. [Explanation of Symbols]

[0135] 100 Communication Systems 104 Distribution System 102 Networking Devices 108 Internet 112 Stations 114 Wireless Channels 118 cells or basic service set 142 processing units 144 Transmitter 146 Receiver 148 Antenna 150 memory 152 Input / Output Components or Interfaces 154 Scheduler 202 Processing Units 204 Transceiver 206 Antenna or network interface controller 208 Positioning Module 210 Input / Output Components 212 memory 214 Other communication components 300 trigger frames 302 Frame control field 304 Duration Field 306 Received STA Address (RA) Field 308 Transmitting AP Address (TA) Field 310 Common Information Fields 312 User Information List Fields 314 Paddingfield 316 Frame Check Sequence (FCS) Field 312' User Information Field 342 Association Identifier (AID) subfield 344 Resource Unit (RU) Allocation Subfield 346 UL Forward Error Correction (FEC) Encoding Type Subfield 348 UL Ultra High Reliability (UHR) MCS Subfield 350 Reservation subfields 352 Spatial Stream (SS) Assignment / RA-RU Information Subfield 354 UL Target Received Power Subfield 356 Reservation subfield 358 Trigger-dependent user information subfield 400 Notification Procedure 440 steps 500 EHT PPDU 502 L-STF Field 504 L-LTF Field 506 L-SIG Field 508 RL-SIG Field 510 U-SIG Field 512 EHT-SIG Field 514 EHT-STF Field 516 EHT-LTF Field 518 EHT-Data Field 520 PE Field

Claims

1. Steps to generate signaling for one or more devices, The step of transmitting the signaling to one or more of the aforementioned devices, A multi-input multi-output (MIMO) communication method, A MIMO communication method wherein, for each of the one or more devices, the signaling is for indicating a plurality of streams assigned to the device and a plurality of modulation and coding system (MCS) indices corresponding to each of the plurality of streams.

2. The MIMO communication method according to claim 1, wherein the one or more devices are one or more stations (STAs).

3. The signaling includes a first instruction and a second instruction for each of one or more devices. The MIMO communication method according to claim 1 or 2, wherein for each of the one or more devices, the first instruction is for specifying a plurality of streams assigned to the device, and the second instruction is for specifying a plurality of modulation and coding system (MCS) indices corresponding to each of the plurality of streams.

4. The aforementioned signaling is carried in a trigger frame for uplink (UL) MIMO communication. The trigger frame includes a user information field for each device, The MIMO communication method according to claim 3, wherein the first and second instructions for each device are stored in the corresponding user information field of the trigger frame.

5. The MIMO communication method according to claim 4, wherein the signaling is carried in a trigger frame for uplink (UL) multi-user MIMO (MU-MIMO) communication or UL single-user MIMO (SU-MIMO) communication.

6. The MIMO communication method according to claim 4 or 5, wherein the first instruction also indicates an MCS table comprising a plurality of MCS sets, each MCS set comprising a plurality of entries representing a plurality of candidate MCS indices for the plurality of streams, and the second instruction comprises an MCS set index for indicating one of the plurality of MCS sets.

7. The aforementioned MCS table is one of several candidate MCS tables. The MIMO communication method according to claim 6, wherein the plurality of candidate MCS tables include a single-stream MCS table, and each MCS set of the single-stream MCS table includes its respective MCS index, excluding the MCS index in Dup mode.

8. The MIMO communication method according to claim 6 or 7, wherein the plurality of candidate MCS indices for each MCS set are in non-ascending or descending order as the index of the plurality of streams increases.

9. The plurality of items in each MCS set are the plurality of candidate MCS indices of the MCS set, Each of the aforementioned items in each MCS set includes a base candidate MCS index and one or more index differences from the base candidate MCS index, or The MIMO communication method according to any one of claims 6 to 8, wherein the plurality of items in each MCS set include one or more index differences from a base candidate MCS index and its neighbor candidate MCS index.

10. The MIMO communication method according to claim 4 or 5, wherein the second instruction includes the plurality of candidate MCS indices.

11. The MIMO communication method according to any one of claims 4 to 10, wherein the first and second instructions for each device are stored together with a unique identifier (ID) in the user information field of the trigger frame.

12. The MIMO communication method according to any one of claims 4 to 11, wherein the first instruction is stored in the spatial stream (SS) allocation / RA-RU information subfield of the user information field, and the second instruction is stored in one or more of the UL MCS subfield, the first reservation subfield, the second reservation subfield, and the trigger-dependent user information subfield of the user information field.

13. The MIMO communication method according to claim 12, wherein the first instruction is stored in the last two bits of the SS assignment / RA-RU information subfield of the user information field, and the second instruction is stored in the UL MCS subfield of the user information field.

14. The signaling is carried in a Physical Layer Protocol Data Unit (PPDU) for Downlink (DL) MIMO communication. The MIMO communication method according to claim 3, wherein the first and second instructions for each device are stored in one or more signal (SIG) fields of the PPDU.

15. The MIMO communication method according to claim 14, wherein the one or more SIG fields of the PPDU include one or more of the L-SIG field, RL-SIG field, U-SIG field, and EHT-SIG field.

16. The one or more SIG fields of the PPDU include an EHT-SIG field. The MIMO communication method according to claim 14, wherein the first and second instructions for each device are stored in one or more user-specific fields of the EHT-SIG field for DL ​​MU-MIMO, or in one or more common fields of the EHT-SIG field for DL ​​SU-MIMO.

17. One or more circuits for performing the method described in any one of claims 1 to 16.

18. One or more non-temporary computer-readable storage devices comprising a computer-executable instruction, wherein, when executed, the instruction causes one or more circuits to perform the method according to any one of claims 1 to 16.

19. To obtain multiple streams and multiple MCS indices corresponding to the multiple streams, the steps include receiving signaling from a device, The step of using the plurality of streams to transmit a plurality of signals to the device, along with the parameters of each stream defined by the corresponding one of the plurality of MCS indices, MIMO communication method.

20. The MIMO communication method according to claim 19, wherein the MIMO communication method is performed by STA.

21. The MIMO communication method according to claim 19 or 20, wherein the device is an access point (AP).

22. The MIMO communication method according to any one of claims 19 to 21, wherein the signaling includes a first instruction for indicating the plurality of streams and a second instruction for indicating the plurality of MCS indices.

23. The signaling is carried in a trigger frame for UL MIMO communication. The MIMO communication method according to claim 22, wherein the first and second instructions are stored in the user information field of the trigger frame.

24. The MIMO communication method according to claim 23, wherein the signaling is carried in a trigger frame for UL MU-MIMO communication or UL SU-MIMO communication.

25. The MIMO communication method according to claim 23 or 24, wherein the first instruction also indicates an MCS table comprising a plurality of MCS sets, each MCS set comprising a plurality of entries representing a plurality of candidate MCS indices for the plurality of streams, and the second instruction comprises an MCS set index for indicating one of the plurality of MCS sets.

26. The aforementioned MCS table is one of several candidate MCS tables. The MIMO communication method according to claim 25, wherein the plurality of candidate MCS tables include a single-stream MCS table, and each MCS set of the single-stream MCS table includes its respective MCS index, excluding the MCS index in Dup mode.

27. The MIMO communication method according to claim 25 or 26, wherein the plurality of candidate MCS indices for each MCS set are in non-ascending or descending order as the index of the plurality of streams increases.

28. The plurality of items in each MCS set are the plurality of candidate MCS indices of the MCS set, Each of the aforementioned items in each MCS set includes a base candidate MCS index and one or more index differences from the base candidate MCS index, or The MIMO communication method according to any one of claims 25 to 27, wherein the plurality of items in each MCS set include one or more index differences from a base candidate MCS index and its neighbor candidate MCS index.

29. The MIMO communication method according to claim 23 or 24, wherein the second instruction includes the plurality of candidate MCS indices.

30. The MIMO communication method according to any one of claims 23 to 29, wherein the first and second instructions for each device are stored together with a unique ID in the user information field of the trigger frame.

31. The MIMO communication method according to any one of claims 23 to 30, wherein the first instruction is stored in the SS assignment / RA-RU information subfield of the user information field, and the second instruction is stored in one or more of the UL MCS subfield, the first reservation subfield, the second reservation subfield, and the trigger-dependent user information subfield of the user information field.

32. The MIMO communication method according to claim 31, wherein the first instruction is stored in the last two bits of the SS assignment / RA-RU information subfield of the user information field, and the second instruction is stored in the UL MCS subfield of the user information field.

33. The aforementioned signaling is carried by PPDU for DL ​​MIMO communication. The MIMO communication method according to claim 22, wherein the first and second instructions are stored in one or more SIG fields of the PPDU.

34. The MIMO communication method according to claim 33, wherein the one or more SIG fields of the PPDU include one or more of the L-SIG field, RL-SIG field, U-SIG field, and EHT-SIG field.

35. The MIMO communication method according to claim 33, wherein the one or more SIG fields of the PPDU include an EHT-SIG field, and the first and second instructions for each device are stored in one or more user-specific fields of the EHT-SIG field for DL ​​MU-MIMO, or in one or more common fields of the EHT-SIG field for DL ​​SU-MIMO.

36. The MIMO communication method according to any one of claims 19 to 35, wherein the signals transmitted through each stream are encoded and / or interleaved independently of the signals transmitted through other streams.

37. One or more circuits for performing the method described in any one of claims 19 to 36.

38. One or more non-temporary computer-readable storage devices comprising a computer-executable instruction, wherein, when executed, the instruction causes one or more circuits to perform the method according to any one of claims 19 to 36.

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