Communication device and communication method for double-current dual-carrier modulation

Abstract

The present disclosure provides a communication device and a communication method for dual-flow dual-carrier modulation (DCM), the communication device comprising: a circuit configured to set first information and second information, the first information indicates whether a mapping of two or more modulation symbols modulated from information bits of the signal to two or more subcarriers is applied across two or more spatial streams of orthogonal frequency division multiplexing (OFDM) symbols, and the second information indicates whether a data rate adjustment is applied to the signal; and a transmitter that transmits a signal comprising the first information and the second information using a mapping of two or more modulation symbols across the two or more spatial streams and / or a data rate adjustment.

Description

Technical Field

[0001] The present disclosure relates to communication devices and methods for subcarrier modulation, and more particularly to communication devices and methods for subcarrier modulation across multiple spatial streams. Background Art

[0002] A dual carrier modulation (DCM) scheme is a modulation scheme with frequency diversity to provide lower data rates, extend communication range, and reduce packet error rate (PER), especially in the presence of interference.

[0003] According to the 802.11be Very High Throughput draft, DCM is only applicable to binary phase shift keying (BPSK), rate 1 / 2 coding, and single spatial stream (SS) non-multi-user multiple input multiple output (non-MU-MIMO) transmissions. Extending DCM to two or more spatial streams is a good way to add spatial diversity to the transmission. However, in the case of using more than one spatial stream, the communication range and transmission reliability will be reduced.

[0004] Therefore, a communication device and method for carrier (or subcarrier) modulation is needed to solve this problem, and more specifically, it is necessary to extend subcarrier modulation across two or more space, space-time, space-frequency or transmission streams to support multi-stream transmission.

[0005] Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure. Summary of the invention

[0006] Non-limiting and exemplary embodiments facilitate providing a communication apparatus and a communication method for subcarrier modulation across multiple spatial streams in the context of a WLAN.

[0007] In a first aspect, the present disclosure provides a first communication device, comprising: a circuit configured to set first information and second information, the first information indicating whether to apply mapping of two or more modulation symbols modulated from information bits of a signal to two or more subcarriers across two or more spatial streams of an orthogonal frequency division multiplexing (OFDM) symbol, and the second information indicating whether to apply data rate adjustment to the signal; and a transmitter, which transmits a signal using mapping of two or more modulation symbols across two or more spatial streams and / or data rate adjustment, the signal comprising the first information and the second information.

[0008] In a second aspect, the present disclosure provides a second communication device: a receiver, which receives a signal including first information and second information, the first information indicating whether to apply mapping of two or more modulation symbols modulated from information bits of the signal to two or more subcarriers across two or more spatial streams of an OFDM symbol, and the second information indicating whether to apply data rate adjustment to the signal; and a circuit, which is configured to decode and demodulate the signal to obtain information of information bits mapped to the two or more spatial streams.

[0009] In a third aspect, the present disclosure provides a communication method implemented by a first communication device, comprising: setting first information and second information, the first information indicating whether to apply a mapping of two or more modulation symbols modulated from information bits of a signal to two or more subcarriers across two or more spatial streams of an OFDM symbol, and the second information indicating whether to apply a data rate adjustment to the signal; and sending a signal utilizing the mapping of two or more modulation symbols across two or more spatial streams and / or data rate adjustment, the signal comprising the first information and the second information.

[0010] In a fourth aspect, the present disclosure provides a communication method implemented by a second communication device, comprising: receiving a signal including first information and second information, the first information indicating whether mapping of two or more modulation symbols modulated from information bits of the signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol, the second information indicating whether data rate adjustment is applied to the signal; and decoding and demodulating the signal to obtain information of information bits mapped to the two or more spatial streams.

[0011] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof.

[0012] Additional benefits and advantages of the disclosed embodiments will become apparent from this specification and the accompanying drawings. Benefits and / or advantages may be obtained individually from the various embodiments and features of the specification and the accompanying drawings, and these embodiments and features do not need to be provided in full in order to obtain one or more such benefits and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present disclosure will be better understood by those of ordinary skill in the art and will be apparent to those of ordinary skill in the art through the following written description which is given by way of example only and in conjunction with the accompanying drawings, in which:

[0014] Figure 1 Depicted is a schematic diagram illustrating single user (SU) communication between an access point (AP) and a station (STA) in a MIMO (Multiple Input Multiple Output) wireless network.

[0015] Figure 2 Depicted is a schematic diagram illustrating downlink multi-user (MU) communication between an AP and multiple STAs in a MIMO wireless network.

[0016] Figure 3 Depicted is a schematic diagram illustrating trigger-based (TB) uplink MU communication between an AP and multiple STAs in a MIMO wireless network.

[0017] Figure 4 A block diagram illustrating a dual carrier modulation (DCM) scheme applied to information bits of a spatial stream (SS) from an orthogonal frequency division multiplexing (OFDM) symbol is shown.

[0018] Figure 5 A transmission block diagram illustrating processing of a data field using a typical DCM scheme is shown.

[0019] Figure 6 Duplicated data in the payload portion of an 80 / 160 MHz physical layer protocol data unit (PPDU) and a 320 MHz PPDU are shown.

[0020] Figure 7 A transmit block diagram illustrating processing of a data field using a typical DCM and a duplicate (DUP) mode is shown.

[0021] Figure 8 A block diagram showing a DCM scheme applied to two information bits across two spatial streams of an OFDM symbol is shown.

[0022] Fig. 9 A block diagram showing the SFBS scheme applied to two information bits across two spatial streams (SS1, SS2) of an OFDM symbol is shown.

[0023] Fig.10 An example extremely high throughput (EHT) PPDU for subcarrier modulation across multiple spatial streams is shown in accordance with an embodiment of the present disclosure.

[0024] Fig.11 Another example EHTP PDU for subcarrier modulation across multiple spatial streams according to an embodiment of the present disclosure is shown.

[0025] Fig.12 A schematic diagram of a communication device according to the present disclosure is shown.

[0026] Fig.13 A flow chart illustrating a communication method implemented by a first communication device according to various embodiments of the present disclosure is shown.

[0027] Fig.14A flowchart illustrating a communication method implemented by a second communication device according to various embodiments of the present disclosure is shown.

[0028] Fig.15 A block diagram illustrating an enhanced frequency diversity scheme applied to two information bits across two spatial streams of an OFDM symbol according to a first embodiment of the present disclosure is shown.

[0029] Fig.16 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to a first embodiment of the present disclosure is shown.

[0030] Fig.17 A block diagram illustrating an enhanced frequency diversity scheme with spatial replication option applied to information bits of each spatial stream across OFDM symbols according to a second embodiment of the present disclosure is shown.

[0031] Fig.18 A block diagram illustrating an enhanced frequency diversity scheme with another spatial replication option applied to information bits of each spatial stream across OFDM symbols according to a second embodiment of the present disclosure is shown.

[0032] Fig.19 A transmission block diagram illustrating processing of a data field by enhancing frequency diversity according to a second embodiment of the present disclosure is shown.

[0033] Fig. 20 A block diagram illustrating an enhanced frequency scheme and permutation options applied to information bits of each spatial stream across OFDM symbols according to a third embodiment of the present disclosure is shown.

[0034] Fig.21 A block diagram illustrating an enhanced frequency diversity scheme and another permutation option applied to information bits of each spatial stream across OFDM symbols according to a third embodiment of the present disclosure is shown.

[0035] Fig. 22 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to a third embodiment of the present disclosure is shown.

[0036] Fig.23 A block diagram illustrating an enhanced frequency diversity scheme applied to two information bits from spatial streams of two OFDM symbols to generate a space-time stream (STS) using space-time block coding (STBC) according to a fourth embodiment of the present disclosure is shown.

[0037] Fig.24 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to a fourth embodiment of the present disclosure is shown.

[0038] Fig.25A block diagram illustrating an enhanced frequency diversity scheme applied to two information bits across two spatial streams of an OFDM symbol according to a fifth embodiment of the present disclosure is shown.

[0039] Fig.26 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to a fifth embodiment of the present disclosure is shown.

[0040] Fig. 27 An example payload portion of a PPDU according to a sixth embodiment of the present disclosure is shown, in which a time domain based repetition option is applied.

[0041] Fig.28 An example payload portion of a PPDU according to a sixth embodiment of the present disclosure is shown, in which another time domain-based repetition option is applied.

[0042] Fig.29 A block diagram illustrating other time-domain based repetition options applied to OFDM symbols within the payload portion of a PPDU according to a sixth embodiment of the present disclosure is shown.

[0043] Fig.30 An example payload portion of a PPDU according to a sixth embodiment of the present disclosure is shown, in which yet another time domain-based repetition option is applied.

[0044] Fig.31 A block diagram illustrating yet another time-domain based repetition option applied to two information bits from spatial streams of two OFDM symbols to generate four OFDM symbols using a subcarrier-time block coding scheme (CTBC) according to a sixth embodiment of the present disclosure is shown.

[0045] Fig.32 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme to which a reliability improvement method is applied according to a sixth embodiment of the present disclosure is shown.

[0046] Fig.33 An example 160 MHz PPDU to which 1 / 2-based frequency replication is applied according to the seventh embodiment of the present disclosure is shown.

[0047] Fig.34 An example 160 MHz PPDU to which frequency replication based on 1 / 4 is applied according to the seventh embodiment of the present disclosure is shown.

[0048] Fig.35 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to a seventh embodiment of the present disclosure is shown.

[0049] Fig.36A first example codeword in a payload portion of a PPDU generated using a special LDPC coding scheme according to an eighth embodiment of the present disclosure is shown.

[0050] Fig.37 A second example codeword in the payload portion of a PPDU generated using a special LDPC coding scheme according to an eighth embodiment of the present disclosure is shown.

[0051] Fig.38 A third example codeword in the payload portion of a PPDU generated using a special LDPC coding scheme according to an eighth embodiment of the present disclosure is shown.

[0052] Fig.39 An example codeword including two concatenated code blocks generated from an information block using another special LDPC coding scheme according to an eighth embodiment of the present disclosure is shown.

[0053] Fig.40 A transmission block diagram illustrating processing of a data field through an enhanced frequency diversity scheme according to an eighth embodiment of the present disclosure is shown.

[0054] Those skilled in the art will appreciate that the elements in the drawings are shown for simplicity and clarity and are not necessarily depicted to scale. For example, the size of some elements in the diagrams, block diagrams or flow charts may be exaggerated relative to other elements to help accurately understand the present embodiment. DETAILED DESCRIPTION

[0055] Some embodiments of the present disclosure will be described by way of example only with reference to the accompanying drawings. Like reference numerals and characters in the drawings represent like elements or equivalents.

[0056] In the following paragraphs, certain exemplary embodiments are explained with reference to access points (APs) and stations (STAs) for subcarrier modulation across multiple spatial streams, particularly in a multiple-input multiple-output (MIMO) wireless network.

[0057] In the context of IEEE 802.11 (Wi-Fi) technology, a station, interchangeably referred to as a STA, is a communication device capable of using the 802.11 protocol. Based on the definition of IEEE 802.11-2016, a STA can be any device that includes a medium access control (MAC) and physical layer (PHY) interface compliant with IEEE 802.11 to a wireless medium (WM).

[0058] For example, a STA can be a laptop, desktop personal computer (PC), personal digital assistant (PDA), access point, or Wi-Fi phone in a wireless local area network (WLAN) environment. A STA can be fixed or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user equipment", and "node" are often used interchangeably.

[0059] Likewise, an AP (which may be interchangeably referred to as a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technology) is a communication device that allows STAs in a WLAN to connect to a wired network. An AP is typically connected to a router as a standalone device (via a wired network), but it may also be integrated with or used in a router.

[0060] As described above, a STA in a WLAN can be used as an AP at different times, and vice versa. This is because a communication device in the scenario of IEEE802.11 (Wi-Fi) technology can include both STA hardware components and AP hardware components. In this way, the communication device can switch between STA mode and AP mode based on actual WLAN conditions and / or requirements.

[0061] In a MIMO wireless network, "multiple" refers to multiple antennas used for transmission simultaneously and multiple antennas used for reception simultaneously on a radio channel. In this regard, "multiple input" refers to multiple transmitter antennas that input radio signals into a channel, and "multiple output" refers to multiple receiver antennas that receive radio signals from a channel and enter a receiver. For example, in an N×M MIMO network system, N is the number of transmitter antennas, M is the number of receiver antennas, and N may or may not be equal to M. For simplicity, the respective numbers of transmitter antennas and receiver antennas are not further discussed in this disclosure.

[0062] In a MIMO wireless network, single-user (SU) communication and multi-user (MU) communication can be deployed for communication between communication devices such as APs and STAs. MIMO wireless networks have benefits such as spatial multiplexing and spatial diversity, which achieve higher data rates and robustness by using multiple spatial streams.

[0063] In the following various embodiments, each of the terms “channel” and “sub-channel” may be used interchangeably with any of “frequency band”, “sub-band” and “frequency segment”.

[0064] Figure 1A schematic diagram illustrating SU communication 100 between an AP 102 and a STA 104 in a MIMO wireless network is depicted. As shown, the MIMO wireless network may include one or more STAs (e.g., STA 104, STA 106, etc.). If the SU communication 100 in a channel is performed over the entire channel bandwidth, it is referred to as full-bandwidth SU communication. If the SU communication 100 in a channel is performed over a portion of the channel bandwidth (e.g., one or more 20 MHz sub-channels within the channel are truncated), it is referred to as truncated SU communication. In the SU communication 100, the AP 102 uses multiple antennas (e.g., Figure 1 The four antennas shown in the figure are used to transmit multiple space-time streams, where all space-time streams are directed to a single communication device (ie, STA104). For simplicity, multiple space-time streams directed to STA104 are shown as packet data transmission arrows 108 directed to STA104.

[0065] SU communication 100 may be configured for bidirectional transmission. Figure 1 As shown, in SU communication 100, STA 104 may use multiple antennas (e.g., Figure 1 The AP 102 may be configured to transmit multiple space-time streams using two antennas (shown) where all space-time streams are directed toward the AP 102. For simplicity, the multiple space-time streams directed toward the AP 102 are shown as packet data transmission arrows 110 directed toward the AP 102.

[0066] therefore, Figure 1 The SU communication 100 depicted in FIG. 1 implements both uplink SU transmissions and downlink SU transmissions in a MIMO wireless network.

[0067] Figure 2A schematic diagram is depicted showing downlink MU (multi-user) communication 200 between an AP 202 and multiple STAs 204, 206, 208 in a MIMO wireless network. The MIMO wireless network may include one or more STAs (e.g., STA 204, STA 206, STA 208, etc.). The MU communication 200 may be an OFDMA (orthogonal frequency division multiple access) communication or a MU-MIMO communication. For OFDMA communication in a channel, the AP 202 simultaneously transmits multiple streams to the STAs 204, 206, 208 in the network at different resource units (RUs) within the channel bandwidth. For MU-MIMO communication in a channel, the AP 202 simultaneously transmits multiple streams to the STAs 204, 206, 208 at the same RU within the channel bandwidth using multiple antennas via spatial mapping or precoding techniques. If the RUs used for OFDMA or MU-MIMO communication occupy the entire channel bandwidth, the OFDMA or MU-MIMO communication is referred to as full-bandwidth OFDMA or MU-MIMO communication. If the RU used for OFDMA or MU-MIMO communication occupies a portion of the channel bandwidth (e.g., one or more 20MHz subchannels within the channel are truncated), the OFDMA or MU-MIMO communication is referred to as truncated OFDMA or MU-MIMO communication. For example, two space-time streams may be directed to STA 206, another space-time stream may be directed to STA 204, and yet another space-time stream may be directed to STA 208. For simplicity, the two space-time streams directed to STA 206 are shown as packet data transmission arrows 212, the space-time stream directed to STA 204 is shown as data transmission arrows 210, and the space-time stream directed to STA 208 is shown as data transmission arrows 214.

[0068] To achieve uplink MU transmission, trigger-based communication is provided to the MIMO wireless network. In this regard, Figure 3 A schematic diagram illustrating trigger-based (TB) uplink MU communication 300 between an AP 302 and a plurality of STAs 304, 306, 308 in a MIMO wireless network is depicted.

[0069] Since there are multiple STAs 304 , 306 , 308 that respectively participate in the triggered uplink MU communication, the AP 302 needs to coordinate simultaneous transmissions of the multiple STAs 304 , 306 , 308 .

[0070] For this reason, Figure 3As shown in FIG, AP 302 simultaneously sends trigger frames 310, 314, 318 to STAs 304, 306, 308, respectively, to indicate user-specific resource allocation information (e.g., the number of space-time streams, the starting STS number, and the allocated RUs) that each STA can use. In response to the trigger frames, STAs 304, 306, 308 can then simultaneously send their respective space-time streams to AP 302 according to the user-specific resource allocation information indicated in the trigger frames 310, 314, 318. For example, two space-time streams can be directed from STA 306 to AP 302, another space-time stream can be directed from STA 304 to AP 302, and yet another space-time stream can be directed from STA 308 to AP 302. For simplicity, two space-time streams directed from STA 306 to AP 302 are shown as packet data transmission arrows 316, the space-time stream directed from STA 304 to AP 302 is shown as data transmission arrow 312, and the space-time stream directed from STA 308 to AP 302 is shown as data transmission arrow 320.

[0071] Due to the packet / PPDU (physical layer protocol data unit) based transmission in the Enhanced Distributed Channel Access (EDCA) mechanism and the distributed MAC (medium access control) scheme in 802.11 WLAN, frequency and space resource scheduling is performed on a packet basis. In other words, resource allocation information is based on PPDU in the EDCA mechanism.

[0072] WLAN supports Figure 1 and Figure 2 The non-trigger based communication shown and Figure 3 In non-trigger-based communication, a communication device sends a PPDU to one or more other communication devices in an unsolicited manner. In trigger-based communication, a communication device sends a PPDU to one or more other communication devices only after receiving a request trigger frame.

[0073] As previously mentioned, the DCM scheme is a modulation scheme with frequency diversity to provide a lower data rate, extend the communication range and reduce the packet error rate (PER), especially when interference exists. Figure 4A block diagram 400 is shown showing a DCM scheme applied to information bits of a spatial stream (SS) from an orthogonal frequency division multiplexing (OFDM) symbol. In a typical DCM scheme, the information bits from the spatial stream are modulated into two modulation symbols using different modulation mappings, i.e., mapped to a subcarrier pair (m, n) within the OFDM symbol. According to 802.11be EHT, the DCM scheme is applicable only to a single spatial stream. The subcarrier pair (m, n) is typically separated far apart in frequency in the spatial stream (e.g., separated by up to N). SD / 2, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., 20 / 40 / 80 MHz subband).

[0074] Figure 5 A transmit block diagram 500 is shown illustrating processing of a data field using a typical DCM scheme. A data field consisting of the following processing blocks may be generated. The transmitter processing may begin with a pre-forward error correction (FEC) physical layer (PHY) padding unit, where redundant information is added to the data bits before the data is output to a scrambler for scrambling the data bits to reduce long runs of the same bit. A low density parity check (LDPC) encoder unit encodes the data bits to add padding bits before the encoded data is output to a post-FEC PHY padding unit so that the number of bits matches the number of bits required for the symbol.

[0075] The stream parser unit then divides the coded bits into multiple blocks, which are then passed through multiple spatial streams (N SS Here, N SS Is 1, which indicates a single spatial stream. The single spatial stream corresponding to the block of coded bits is sent to the constellation mapper unit and the LDPC tone mapper unit. The constellation mapper unit maps the corresponding block of coded bits into constellation points or complex numbers (referred to as modulation symbols herein) using the selected modulation scheme (in this case, BPSK and DCM), and maps the corresponding modulation symbols to two OFDM subcarriers (DCM), and ensures that the corresponding OFDM subcarriers are separated by a sufficient distance to maximize the frequency diversity gain. The LDPC tone mapper unit further interleaves the modulation symbols within the OFDM symbol to protect it from burst errors and better overcome frequency selective fading.

[0076] The spatial streams are then sent to a spatial mapper unit to be mapped onto multiple transmit chains (three transmit chains are shown, each indicated by an arrow pointing out of the spatial mapper unit). Each transmit chain is sent to an inverse Fourier discrete Fourier transform (IDFT) unit. Each IDFT unit converts the OFDM subcarriers on the transmit chain (which are frequency domain data) into time domain data for transmission. The time domain data from the IDFT unit is then sent to an insertion guard interval (GI) and window unit to insert a GI at the beginning of each OFDM symbol in the transmit chain, where each OFDM symbol can also be windowed to minimize adjacent channel interference. The time domain data in each transmit chain is then sent to an analog and radio frequency (RF) unit to prepare the data for transmission through the antenna.

[0077] In the 802.11be EHT draft, DCM can be applied to EHT modulation and coding scheme (MCS) 14 and EHT-MCS15. In EHT-MCS14, BPSK, rate 1 / 2 coding scheme, DCM and duplication (DUP) mode are applied; however, in EHT-MCS15, BPSK, rate 1 / 2 coding scheme and DCM are applied. EHT DUP mode is a mode in which the transmission data in the payload part of the PPDU is duplicated based on a frequency of 1 / 2. The EHT DUP mode can reduce the data rate in a large bandwidth of 80 / 160 / 320MHz in the 6GHz band.

[0078] Figure 6 80 / 160 MHz PPDU 600 and 320 MHz PPDU 620. In the 80 / 160 MHz PPDU, the payload portion may contain symbols X and X modulated from the same information bit via a DCM scheme in a 40 / 80 MHz frequency segment. DCM , and also includes duplication of the modulation symbols in the remaining 40 / 80MHz frequency segment (based on 1 / 2 frequency) via the DUP mode. The duplication may include a phase rotation in one or more of the duplicated symbols. In this case, the modulation symbol X is shifted to -X when duplicated. Similarly, in a 320MHz PPDU, the payload portion may include symbols X and X modulated from the same information bit via the DCM scheme in the 160MHz frequency segment. DCM The generated symbol X L , X L，DCM , X U and X U，DCM , where the symbol X L It is the lower half of the symbol X. U It is the upper part of the symbol X; the symbol X L，DCM It is the symbol X DCMThe lower half of the symbol X U，DCM It is the symbol X DCM The payload portion also contains a copy of the modulation symbols in the remaining 160MHz frequency segment (based on 1 / 2 frequency) via the DUP mode.

[0079] Figure 7 A transmit block diagram 700 is shown showing the processing of the data field using typical DCM and DUP modes. The transmitter processes similar Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream, except that after the LDPC tone mapper unit, the modulation symbols on the spatial stream are sent to a frequency domain replication unit, for example, replicated based on a frequency of 1 / 2, before they are sent to the spatial mapper unit for mapping to multiple transmit chains.

[0080] In 802.11ax HE, DCM is only applicable to HE-MCS 0, 1, 3 and 4, and only up to two spatial streams. In the case of two spatial streams, the same modulation principle is applied to each spatial stream for a single spatial stream. This will only allow frequency diversity gain.

[0081] Figure 8 A block diagram 800 is shown showing a DCM scheme applied to two information bits of two spatial streams (SS1, SS2) across an OFDM symbol. Conventionally, the same modulation principle is applied to two information bits X1, X2 from different spatial streams (SS1, SS2). In particular, each of the information bits X1, X2 is modulated into a symbol pair (X 1k and X 1kDCM , X 2k and X 2kDCM ), which are mapped to subcarrier pairs (m, n) within OFDM symbols in their corresponding spatial streams (SS1, SS2). Similarly, the subcarrier pairs (m, n) are separated far apart in frequency in the spatial streams (e.g., separated by N SD / 2, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., 20 / 40 / 80 MHz subband).

[0082] In contrast to DCM, a space frequency diversity scheme (SFDS) is applied across two spatial streams. An example of SFDS is space frequency block coding (SFBC). Fig. 9A block diagram 900 is shown showing an SFBS scheme applied to two information bits of two spatial streams (SS1, SS2) across an OFDM symbol. In particular, the information bits from the first spatial stream (SS1) are modulated into two modulation symbols X mapped to a subcarrier pair (m, n). 1k , X 1k * One of the modulation symbols (e.g., X 1k ) is mapped to the first subcarrier (m) corresponding to the first spatial stream (SS1), and another modulation symbol (eg, X 1k * ) is mapped to the second subcarrier (n) corresponding to the second spatial stream (SS2). Another information bit from the second spatial stream is also modulated into two modulation symbols X mapped to the subcarrier pair (m, n). 2k , X 2k * One of the modulation symbols (e.g., X 2k ) is mapped to the first subcarrier (m) corresponding to the second spatial stream (SS2), and another modulation symbol (eg, X 2k * ) is mapped to a second subcarrier (n) corresponding to the first spatial stream (SS1). The subcarrier pair (m, n) is separated far apart in frequency in the spatial stream (e.g., separated by N). SD / 2, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., a 20 / 40 / 80 MHz subband). In addition to frequency diversity gain, this SFDS scheme also allows for spatial diversity gain. In modulation schemes including SFDS schemes, where each created stream (e.g., SS1 / SS2) includes a set of identical (or overlapping) information bits (e.g., X1, X2), a stream may be referred to as, for example, a space-frequency stream or a transmission stream, or as a spatial stream.

[0083] As mentioned above, in 802.11be EHT, the DCM scheme is only applicable to a single spatial stream transmission. Extending DCM to two or more spatial streams is a good way to add spatial diversity to transmission. However, in the case of using more than one spatial stream, the communication range and transmission reliability will be reduced. Therefore, a communication device and method for carrier (or subcarrier) modulation are needed to solve this problem, and more specifically, subcarrier modulation needs to be extended across two or more spatial streams to support multiple spatial stream transmissions.

[0084] According to the present disclosure, an enhanced frequency diversity scheme is applied to more than one spatial stream to provide higher or additional diversity gain (e.g., spatial diversity and / or antenna diversity) compared to DCM in the 802.11 specification. Additionally or alternatively, a reliability enhancement method is applied to improve transmission reliability and provide further diversity gain by reducing the data rate.

[0085] In the following various embodiments, the enhanced frequency diversity scheme refers to mapping from two or more modulation symbols modulated from information bits of a signal to two or more subcarriers; and the reliability improvement method refers to data rate adjustment.

[0086] The application of the enhanced frequency diversity scheme (i.e., mapping of two or more modulation symbols modulated from information bits of a signal to two or more subcarriers) and the reliability improvement method (i.e., data rate adjustment) are indicated by first information and second information set by the transmitter AP (or STA), respectively. In one implementation, the application of the enhanced frequency diversity scheme is indicated by the number of spatial streams (N) in the preamble portion of the signal. SS ) and MCS information. The enhanced frequency diversity scheme (eg, enhanced DCM scheme) may be a predefined scheme known to the intended receiver, or a scheme explicitly indicated in the preamble portion of the signal.

[0087] For example, in an EHT MU PPDU, when MCS15 is indicated in the user field of the EHT-SIG field of the PPDU, if N SS The (Number of Spatial Streams) field is 1 (same as 802.11be), indicating the normal DCM scheme, while if N SS The field is 2 (in 802.11be, N SS =2 is reserved), it indicates the enhanced DCM scheme.

[0088] Alternatively, in future implementations and modifications, such application of the enhanced frequency diversity scheme may be indicated only by the MCS information.

[0089] Similarly, the application of the reliability improvement method can be defaulted together with the enhanced frequency diversity scheme, or by N in the preamble part of the signal. SS and MSC information indication.

[0090] For example, in an EHT MU PPDU, when MCS15 and N are indicated in the user field of the EHT-SIG field of the PPDU SS When 3, it indicates an enhanced DCM scheme with improved reliability.

[0091] Alternatively, this application of the reliability improvement method consists of adding MCS and N SS A separate signal field outside of the information (such as Fig.11 Reliability Improvement Flag field shown).

[0092] Note that regardless of whether the reliability improvement method is applied or not, a receiver STA receiving a PPDU having a preamble portion indicating application of an enhanced frequency diversity scheme should follow predefined / indicated instructions to decode and demodulate the PPDU to obtain additional gain.

[0093] Fig.10 An example EHT PPDU 1000 for subcarrier modulation across multiple spatial streams according to an embodiment of the present disclosure is shown. The EHT PPDU 1000 may include a non-high throughput (legacy) short training field (L-STF), a non-high throughput (legacy) long training field (L-LTF), a non-high throughput (legacy) signal (L-SIG) field, a repeated L-SIG (RL-SIG) field, a universal signal (U-SIG) field, an EHT-STF, an EHT-LTF), a data field, and a packet extension (PE) field. The durations of the L-STF, the L-LTF, the L-SIG field, the RL-SIG field, the U-SIG field, the EHT-SIG field, and the EHT-STF are 8 μs, 8 μs, 4 μs, 4 μs, 8 μs, 8 μs, and 8 μs, respectively, and the EHT-LTF includes one or more EHT-LTF symbols with variable durations depending on the guard interval (GI) and the LTF size.

[0094] The EHT-SIG field includes a common field and a user-specific field. The user-specific field includes one or more user fields, each of which includes a STA ID field, an MCS field, an N SS field, beamforming field and coding field. MCS field and / or N SS The MCS field may provide information on whether to apply an enhanced frequency diversity scheme (eg, enhanced DCM) and / or a reliability improvement method. Table 1 is a table consisting of the MCS field and N SS The first example encoding scheme indicated by the field, where N SS Either 1 or 2.

[0095]

[0096]

[0097] Table 1

[0098] Table 2 shows the MCS field and N SS A second example encoding scheme indicated by the field, where N SS Can be 1, 2 or 3.

[0099]

[0100] Table 2

[0101] Fig.11 Another example EHT PPDU 1100 for subcarrier modulation across multiple spatial streams according to an embodiment of the present disclosure is shown. The PPDU 1100 is similar to Fig.10 In the PPDU 1000 shown in the figure, each user field of the user-specific field except the EHT-SIG field also includes a reliability improvement flag field, which is used as a separate signaling to indicate whether to apply the reliability improvement method, and the MCS and N SS The field indicates whether the enhanced frequency diversity scheme is applied. Table 3 shows the MCS field, N SS A second example encoding scheme indicated by the field and the reliability improvement flag field, where N SS Is 1 or 2. If the Nss field is set to 1, the reliability improvement flag may be retained (the value is ignored by the receiver). (As indicated by " / " in Table 3)

[0102]

[0103] Table 3

[0104] Advantageously, these fields are used to provide information about applying an enhanced frequency diversity scheme and reliability improvement method, which can extend DCM to two or more spatial streams and provide spatial diversity gain to DCM and EHT DUP modes without requiring additional signaling bits in the preamble portion of the PPDU or signal.

[0105] Fig.12 A schematic diagram of a communication device 1200 according to the present disclosure is shown. The communication device 1200 may also be implemented as an AP or a STA.

[0106] like Fig.12 As shown, the communication device 1200 may include a circuit 1214, at least one radio transmitter 1202, at least one radio receiver 1204, and at least one antenna 1212 (for simplicity, for the purpose of illustration, Fig.12Only one antenna is depicted in FIG. 1 ). The circuit 1214 may include at least one controller 1206 for software and / or hardware-assisted execution of the tasks that the at least one controller 1206 is designed to perform, including controlling communications with one or more other communication devices in the MIMO wireless network. The circuit 1214 may also include at least one transmit signal generator 1208 and at least one receive signal processor 1210. The at least one controller 1206 may control the at least one transmit signal generator 1208 to generate a PPDU to be sent to one or more other communication devices via the at least one radio transmitter 1202, wherein the PPDU may be, for example, a PPDU for downlink transmission (if the communication device 1200 is an AP) or a PPDU for trigger-based uplink transmission (if the communication device 1200 is a STA). At least one controller 1206 may control at least one receive signal processor 1210 to process MAC frames and PPDUs received from one or more other communication devices through at least one radio receiver 1204 under the control of at least one controller 1206, wherein the PPDU may be, for example, a PPDU for uplink transmission based on triggering (if the communication device 1200 is an AP), or a PPDU for downlink transmission (if the communication device 1200 is a STA). At least one transmit signal generator 1208 and at least one receive signal processor 1210 may be independent modules of the communication device 1200, which communicate with at least one controller 1206 to implement the above functions, such as Fig.12 As shown. Alternatively, at least one transmit signal generator 1208 and at least one receive signal processor 1210 may be included in at least one controller 1206. Those skilled in the art will appreciate that the arrangement of these functional modules is flexible and may vary according to actual needs and / or requirements. Data processing, storage and other related control devices may be provided on appropriate circuit boards and / or in chipsets. In various embodiments, when in operation, at least one radio transmitter 1202, at least one radio receiver 1204 and at least one antenna 1212 may be controlled by at least one controller 1206.

[0107] The communication device 1200 may provide the functionality required for subcarrier modulation across multiple spatial streams when in operation. For example, the communication device 1200 may be an AP or a transmitter STA, and the circuit 1214 (e.g., at least one transmit signal generator 1208 of the circuit 1214, respectively) may be configured to set the first information and the second information. The first information may indicate whether a mapping of two or more modulation symbols modulated from information bits of a signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol. The second information may indicate whether a data rate adjustment is applied to the signal. At least one radio transmitter 1202 may transmit a signal using a mapping of two or more modulation symbols across two or more spatial streams and / or a data rate adjustment. The signal may include both the first information and the second information.

[0108] In one embodiment, the circuit 1214 (e.g., at least one transmit signal generator 1208 of the circuit 1214, respectively) is further configured to: set the MCS coding scheme (e.g., MCS field) and / or the number of spatial streams (N SS The signal field (e.g., reliability improvement flag) is used to include the first information and the second information. In an alternative embodiment, the second information is indicated by setting a separate signal field (e.g., reliability improvement flag).

[0109] In various embodiments, applying a mapping from two or more modulation symbols modulated from information bits of a signal to two or more subcarriers across two or more spatial streams of an OFDM symbol comprises one of:

[0110] a) mapping two modulation symbols of two or more modulation symbols modulated from information bits to a first subcarrier of two or more subcarriers in a first spatial stream of two or more spatial streams of an OFDM symbol and a second subcarrier of two or more subcarriers in a second spatial stream of two or more spatial streams of the OFDM symbol, respectively;

[0111] b) the same mapping of two modulation symbols of two or more modulation symbols modulated by the information bits to two or more subcarriers in each of the two or more spatial streams;

[0112] c) mapping two modulation symbols of two or more modulation symbols modulated by a first information bit of a signal to two or more subcarriers in a first spatial stream of two or more spatial streams of an OFDM symbol and a second spatial stream of two or more spatial streams of an adjacent OFDM symbol, and mapping two modulation symbols of two or more modulation symbols modulated by a second information bit of the signal to two or more subcarriers in a second spatial stream of two or more spatial streams of an OFDM symbol and a first spatial stream of two or more spatial streams of an adjacent OFDM symbol; and the transmitter transmits the signal through the OFDM symbol and the first spatial stream and the second spatial stream of the adjacent OFDM symbol;

[0113] d) a phase rotation of one modulation symbol among two or more modulation symbols mapped to one subcarrier among two or more subcarriers in one spatial stream of two or more spatial streams of the OFDM symbol;

[0114] e) sign inversion of one modulation symbol among two or more modulation symbols mapped to one subcarrier among two or more subcarriers in one spatial stream of two or more spatial streams of the OFDM symbol;

[0115] f) conjugation of one modulation symbol among two or more modulation symbols mapped to one subcarrier among two or more subcarriers in one spatial stream of two or more spatial streams of the OFDM symbol;

[0116] g) switching of two modulation symbols of two or more modulation symbols mapped to two subcarriers of two or more subcarriers in one spatial stream of two or more spatial streams;

[0117] h) phase rotation, sign reversal, or conjugation of one of two or more modulation symbols mapped to one of two or more subcarriers in one of two or more spatial streams in one of the one or more replicas of the OFDM symbol;

[0118] i) sign inversion of one of two or more modulation symbols mapped to one of two or more subcarriers in one of two or more spatial streams in one of the one or more replicas of the OFDM symbol; and

[0119] j) conjugation of one of two or more modulation symbols mapped to one of two or more subcarriers in one of two or more spatial streams in one of the one or more replicas of the OFDM symbol.

[0120] In various embodiments, the data rate adjustment includes one of:

[0121] a) the data rate adjustment corresponds to a replica of an OFDM symbol in a payload portion of the signal; and the transmitter transmits a signal including the OFDM symbol in the payload portion and one or more replicas of OFDM symbols immediately adjacent to the OFDM symbol;

[0122] b) the data rate adjustment corresponds to a copy of an OFDM symbol block in a payload portion of the signal; and the transmitter transmits a signal comprising the OFDM symbol block in the payload portion and one or more copies of an OFDM symbol block immediately adjacent to the OFDM symbol block, the OFDM symbol block comprising the OFDM symbol and one or more adjacent OFDM symbols;

[0123] c) switching of two modulation symbols of two or more modulation symbols mapped to two subcarriers of two or more subcarriers in one of one or more copies of an OFDM symbol; and

[0124] d) frequency replication of a payload portion of the signal to generate a signal comprising information bits in the first frequency segment and one or more replications of information bits in the one or more second frequency segments of the payload portion of the signal.

[0125] For example, the communication device 1200 may be a receiver STA, and at least one radio receiver 1204 may receive a signal including first information and second information. The first information may indicate whether mapping of two or more modulation symbols modulated from information bits of the signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol. The second information may indicate whether data rate adjustment is applied to the signal. The circuit 1214 (e.g., at least one receive signal processor 1210 of the circuit 1214, respectively) may be configured to decode and demodulate the signal to obtain information of information bits mapped to two or more spatial streams.

[0126] Fig.13A flowchart 1300 showing a communication method implemented by a first communication device is shown. For example, according to various embodiments of the present disclosure, the first communication device may be an AP or a transmitter STA. In step 1302, a step of setting first information (modulation symbol mapping information) and second information (data rate adjustment information) is performed. The first information may indicate whether mapping of two or more modulation symbols modulated from information bits of a signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol, and the second information may indicate whether data rate adjustment is applied to the signal. In step 1304, a step of sending a signal using mapping of two or more modulation symbols across two or more spatial streams and / or data rate adjustment is performed, wherein the signal may include the first information and the second information.

[0127] Fig.14 A flowchart 1400 showing a communication method implemented by a second communication device is shown. For example, according to various embodiments of the present disclosure, the second communication device may be a receiver STA. In step 1402, a step of receiving a signal including first information (modulation symbol mapping information) and second information (data rate adjustment information) is performed, the first information indicating whether mapping of two or more modulation symbols modulated from information bits of the signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol, and the second information indicating whether data rate adjustment is applied to the signal. In step 1404, a step of decoding and demodulating the signal to obtain information of information bits mapped to the two or more spatial streams is performed.

[0128] In the following paragraphs, a first embodiment of the present disclosure is described in which an enhanced frequency diversity scheme such as a spatial frequency diversity scheme (SFDS) applied to more than one spatial stream (SS) is applied without a reliability improvement method.

[0129] Fig.15 A block diagram 1500 is shown showing an enhanced frequency diversity scheme applied to two information bits of two spatial streams (SS1, SS2) across OFDM symbols according to a first embodiment of the present disclosure. In particular, the SFDS scheme is applied, and the information bits from the first spatial stream (SS1) are modulated to two modulation symbols X mapped to a subcarrier pair (m, n). 1k , X 1kDCM One of the modulation symbols (e.g., X 1k ) is mapped to the first subcarrier (m) corresponding to the first spatial stream (SS1), and another modulation symbol (eg, X 1kDCM ) is mapped to the second subcarrier (n) corresponding to the second spatial stream (SS2). Another information bit from the second spatial stream is also modulated into two modulation symbols X mapped to the subcarrier pair (m, n). 2k, X 2kDCM One of the modulation symbols (e.g., X 2k ) is mapped to the first subcarrier (m) corresponding to the second spatial stream (SS2), and another modulation symbol (eg, X 2kDCM ) is mapped to a second subcarrier (n) corresponding to the first spatial stream (SS1). The subcarrier pair (m, n) is separated far apart in frequency in the spatial stream (e.g., separated by N). SD / 2, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., 20 / 40 / 80 MHz subband).

[0130] Preferably, phase rotation or symbol inversion is applied to the modulation symbols on the partial frequency subcarriers from the spatial streams (e.g., the second modulation symbols from other information bits mapped to the second subcarrier (n) corresponding to the first spatial stream are rotated from X to N. 2kDCM Rotate or invert to -X 2kDCM ) to distinguish from a corresponding modulation symbol from another spatial stream (e.g., from an information bit (e.g., X) mapped to the same second subcarrier (n) corresponding to the second spatial stream 1kDCM )’s second modulation symbol).

[0131] Advantageously, such SFDS scheme applied to more than one SS may provide some spatial diversity gain in certain propagation environments. For example, in a flat fading channel / line of sight (LOS) small room environment, more than one SS may perform better due to spatial diversity. In a non-line of sight (NLOS) large room environment, the spatial diversity effect may be small because the frequency diversity effect is large enough. There may be no spatial diversity gain to apply SFDS on more than one SS in an AWGN channel with the same total power.

[0132] Note that more than one spatial stream transmission should be sent to a single user. A receiver STA receiving a PPDU with a preamble indicating that SFDS is applied across more than one spatial stream should combine the demodulated symbols from different SSs after SFDS mapping before decoding the PPDU to obtain signal and spatial diversity gain.

[0133] Fig.16 A transmission block diagram 1600 is shown showing the processing of the data field by an enhanced frequency diversity scheme according to the first embodiment of the present disclosure. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS=1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream. Specifically, in this first embodiment, the constellation mapper unit maps corresponding blocks of coded bits to modulation symbols using BPSK, DCM and SFDS schemes, and maps each modulation symbol to two OFDM subcarriers before sending the symbol to the LDPC tone mapper unit and the spatial mapper unit to map the spatial stream to one or more transmit chains (each indicated by an arrow pointing out from the spatial mapper unit).

[0134] In the following paragraphs, a second embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme such as dual carrier modulation (DCM) applied to more than one spatial stream (SS) is applied without a reliability improvement method. In contrast to the conventional DCM scheme, according to the DCM of this embodiment, the same information bits and modulation symbols are copied to more than one SS, i.e., spatial replication, in which cyclic shift diversity (CSD) is applied.

[0135] According to the second embodiment, when application of an enhanced frequency diversity scheme is indicated, two different options / examples of spatial replication may be applied: (1) normal spatial replication without CSD; and (2) spatial replication with CSD such as partial phase rotation or sign reversal.

[0136] Fig.17 A block diagram 1700 illustrating an enhanced frequency diversity scheme with spatial replication under option 1 applied to information bits of each spatial stream across OFDM symbols according to a second embodiment of the present disclosure is shown. Fig.18 A block diagram 1800 illustrating an enhanced frequency diversity scheme with spatial replication under option 2 applied to information bits of each spatial stream across OFDM symbols according to a second embodiment of the present disclosure is shown.

[0137] refer to Fig.17 In the enhanced frequency diversity scheme under option 1 according to the second embodiment, the DCM scheme with normal spatial replication is applied to more than one spatial stream. In particular, the information bits are modulated into two modulation symbols X mapped to the subcarrier pair (m, n) corresponding to the first spatial stream (SS1). 1k , X 1kDCM The same modulation symbol X 1k , X 1kDCM and its subcarrier (m, n) mapping is also copied to the second spatial stream (SS2). The subcarrier pairs (m, n) are separated far apart in frequency in the spatial stream (e.g., separated by N SD / 2, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., 20 / 40 / 80 MHz subband).

[0138] refer to Fig.18 In the enhanced frequency diversity scheme under option 2 according to the second embodiment, the DCM scheme with spatial replication and CSD is applied to more than one spatial stream. In particular, the information bits are modulated into two modulation symbols X mapped to the subcarrier pair (m, n) corresponding to the first spatial stream (SS1). 1k , X 1kDCM The same modulation symbol X 1k , X 1kDCM and its subcarrier (m, n) mapping is also copied to the second spatial stream (SS2). In contrast to Option 1, a phase rotation or symbol reversal is applied to the modulation symbols on the partial frequency subcarriers from the spatial stream (e.g., the second modulation symbol mapped to the second subcarrier (n) corresponding to the second spatial stream is shifted from X to N. 1kDCM Rotate or invert to -X 1kDCM ) to distinguish the same modulation symbol from another spatial stream (e.g., the modulation symbol X mapped to the second subcarrier (n) corresponding to the first spatial stream) 1kDCM ). In this way, a lower peak-to-average power ratio (PAPR) and higher robustness can be achieved.

[0139] Under this scheme, a receiver STA that receives a PPDU with a preamble indicating that DCM with / without rotational spatial replication is applied across more than one spatial stream (option 1 or 2) should combine the demodulated symbols from different SSs after mapping before decoding the PPDU to obtain spatial diversity and robustness gain.

[0140] Advantageously, such a DCM scheme with spatial replication applied to more than one SS can provide spatial diversity gain although it has the same data rate and performance as DCM with a single SS or transmission of a single SS with 2 transmitter antennas.

[0141] Fig.19 A transmission block diagram 1900 is shown showing processing of a data field by enhancing frequency diversity according to a second embodiment of the present disclosure. The transmitter processes similarly to Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding, a stream parser unit (N SS=1), a constellation mapper unit, and an LDPC tone mapper unit to process a single spatial stream. Specifically, in this second embodiment, after the LDPC tone mapper unit, the spatial stream is sent to the spatial replication unit, where the modulation symbols on the spatial stream are replicated to two spatial streams (each indicated by an arrow pointing from the spatial replication unit). The spatial stream and the replicated spatial stream are then sent to the spatial mapper unit to be mapped to two or more transmit chains. Optionally, under Option 2, one of the multiple spatial streams from the spatial replication unit is sent to the CSD unit to perform phase rotation or symbol inversion on its modulation symbols before the spatial stream is sent to the spatial mapper unit to be mapped to the three transmit chains.

[0142] In the following paragraphs, a third embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme such as dual carrier modulation (DCM) applied to more than one spatial stream (SS) is applied without a reliability improvement method. In contrast to the conventional DCM scheme, according to the DCM of this embodiment, the same information bit is modulated to two or more modulation symbols using different modulation mappings (e.g., two DCM schemes), and the modulation symbols are permuted between different SSs. The permutation is performed on the frequency subcarriers of the OFDM symbol.

[0143] According to the third embodiment, when application of an enhanced frequency diversity scheme is indicated, two different options / examples of frequency subcarrier permutation may be applied: (1) performing permutation between subcarrier blocks of a symbol; and (2) performing permutation between adjacent two or more subcarriers of a symbol.

[0144] Fig. 20 A block diagram 2000 is shown illustrating an enhanced frequency scheme and permutation under Option 1 applied to information bits of each spatial stream across OFDM symbols according to a third embodiment of the present disclosure. Fig.21 A block diagram 2100 is shown illustrating an enhanced frequency diversity scheme and permutation under option 2 applied to information bits of each spatial stream across OFDM symbols according to a third embodiment of the present disclosure.

[0145] In the enhanced frequency diversity scheme according to the third embodiment, two different modulation mappings are used to modulate the information bit X1 on a spatial stream (e.g., the first spatial stream SS1), each modulation mapping generating a modulation symbol pair. In particular, the first modulation mapping generates modulation symbols X1 mapped to subcarriers m1 and n1 corresponding to the first spatial stream SS1, respectively. 1k-1 and X 1kDCM-1 ; and the second modulation mapping generates modulation symbols X respectively mapped to subcarriers m2 and n2 corresponding to the same SS1 1k-2 and X 1kDCM-2 The modulation symbols are then permuted and mapped to another SS (eg, SS2).

[0146] refer to Fig. 20 , under option 1, apply the symbol X on m1, m2, n1, and n2 respectively 1k-1 , X 1kDCM-1 , X 1k-2 and X 1kDCM-2 In particular, the mapping sequence of the subcarrier blocks of symbols in the first spatial stream (SS1) is permuted and reversed in the second spatial stream (SS2). The first symbol (X 1k-1 ) is replaced by the fourth subcarrier index n2 in SS2; the second symbol (X) mapped to the second subcarrier index m2 in SS1 1kDCM-1 ) is replaced by the third subcarrier index n1 in SS2; the third symbol (X) mapped to the third subcarrier index n1 in SS1 1k-2 ) is replaced by the second subcarrier index m2 in SS2; the fourth symbol (X) mapped to the fourth subcarrier index n2 in SS1 1kDCM-2 ) is replaced by the first subcarrier index m1 in SS2.

[0147] refer to Fig.21 , under option 2, permutation is performed between two adjacent subcarriers of a symbol. Specifically, two adjacent subcarriers of a symbol are grouped (e.g., X 1k-1 and X 1kDCM-1 ;X 1k-2 and X 1kDCM-2 ), and the mapping sequence of two adjacent subcarriers of the symbol in the first spatial stream (SS1) is permuted and reversed in the second spatial stream (SS2). The first symbol (X) mapped to the first subcarrier index m in SS1 1k-1 ) is replaced by the second subcarrier index m+1 in SS2; the second symbol (X) mapped to the second subcarrier index n in SS1 1kDCM-1 ) is replaced by the first subcarrier index n+1 in SS2; the third symbol (X) mapped to the third subcarrier index m+1 in SS1 1k-2 ) is replaced by the fourth subcarrier index m in SS2; the fourth symbol (X) mapped to the fourth subcarrier index n+1 in SS1 1kDCM-2 ) is replaced by the third subcarrier index n in SS2.

[0148] According to an embodiment, such permutation between spatial streams can be applied on top of any enhanced frequency diversity scheme described in various embodiments of the present disclosure to further obtain robustness and frequency diversity. Fig. 20As shown, phase rotation or symbol inversion may be applied to modulation symbols on some frequency subcarriers from the spatial stream (e.g., the second modulation symbol mapped to the third subcarrier (n1) corresponding to the second spatial stream is rotated from X to X. 1k-2 Rotate or invert to -X 1k-2 ) to distinguish it from the corresponding modulation symbol from another spatial stream.

[0149] Note that more than one spatial stream transmission should be sent to a single user. Under this scheme, under Option 1 or 2 according to this third embodiment, a receiver STA that receives a PPDU with a preamble indicating that permutation between spatial streams with / without rotation is applied across more than one spatial stream should combine demodulated symbols from different SSs after mapping before decoding the PPDU to obtain spatial diversity and robustness gain.

[0150] Advantageously, such a DCM scheme with spatial replication applied to more than one SS can provide spatial diversity gain and further frequency diversity gain at the same data rate as DCM with a single SS, as well as better robustness since one information bit can also be carried in 2N subcarriers on N SSs.

[0151] Fig. 22 A transmission block diagram 2200 is shown showing the processing of the data field by an enhanced frequency diversity scheme according to the third embodiment of the present disclosure. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream to process a single spatial stream. Specifically, in this third embodiment, after the constellation mapper unit maps the corresponding block of coded bits to modulation symbols using the BPSK, DCM scheme, the modulation symbols are sent to the permutation unit to perform permutation of frequency subcarriers in the spatial stream, and each modulation symbol is mapped to two OFDM subcarriers before the symbols mapped to the spatial stream are sent to the LDPC tone mapper unit and the spatial mapper unit to map the spatial stream to one or more transmit chains.

[0152] In the following paragraphs, a fourth embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme such as dual carrier modulation (DCM) applied to a space-time stream (STS) generated from one or more SSs through a space-time block coding (STBC) scheme is applied without a reliability improvement method.

[0153] STBC is a robust transmission technique for OFDM symbols, where the same information bits from an SS are further mapped into more than one STS, or in other words, n SSs are mapped into 2n STSs. The STBC operation should occur between the constellation mapper and the spatial mapper. In particular, the STBC process operates on the complex modulation symbols in the sequence pairs of OFDM symbols.

[0154] Fig.23 A block diagram 2300 illustrating an enhanced frequency diversity scheme applied to two information bits from spatial streams of two OFDM symbols to generate STS using STBC according to a fourth embodiment of the present disclosure is shown.

[0155] The information bit X1 from the spatial stream (eg, the first spatial stream SS1) is modulated into a modulation symbol pair X on OFDM symbol 2n using the DCM scheme. 1k and X 1kDCM The second information bit X2 from the spatial stream SS1 is modulated into a modulation symbol pair X on the adjacent OFDM symbol 2n+1 using the DCM scheme. 2k and X 2kDCM .

[0156] In the enhanced frequency diversity scheme according to the fourth embodiment, the modulation symbols from the SS (SS1) are processed by the STBC unit and mapped to two STSs (STS1 and STS2), each of which contains the same modulation symbols. Fig.23 As shown, the two STSs can come from different OFDM symbols. In particular, the modulation symbol X of SS1 from OFDM symbol 2n 1k , X 1kDCM X in STS1 is mapped to OFDM symbol 2n 1k , X 1kDCM and -X in STS2 of the adjacent OFDM symbol 2n+1 * 1k , -X * 1kDCM , and the modulation symbol X from SS1 of OFDM symbol 2n+1 2k , X 2kDCM X in STS1 mapped to OFDM symbol 2n+1 2k , X 2kDCM and -X in STS2 of the adjacent OFDM symbol 2n * 2k , X * 2kDCM In this example, phase rotation or sign reversal is applied to the adjacent symbols (e.g., X * 1k , X *2k )’s OFDM symbol to distinguish the corresponding modulation symbols from another STS.

[0157] Advantageously, such a DCM scheme and STBC scheme applied to more than one SS to generate two STSs from each SS can provide spatial diversity gain and better robustness at the same data rate as DCM with a single SS.

[0158] Alternatively, unlike the above-mentioned DCM scheme with one SS, the STBC scheme can be applied to DCM with more than one SS. In this case, there will be more than two STs, and more antennas and EHT-LTF symbols are required for transmission.

[0159] According to an embodiment, this DCM scheme between STSs generated by the STBC scheme can be applied to any enhanced frequency diversity scheme described in various embodiments of the present disclosure to further obtain robustness and frequency diversity. Fig.23 As shown, phase rotation or sign reversal is applied to the adjacent symbols (e.g., X * 1k , X * 2k )’s OFDM symbol.

[0160] Fig.24 A transmission block diagram 2400 showing the processing of a data field by an enhanced frequency diversity scheme according to a fourth embodiment of the present disclosure is shown. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream. Specifically, in this fourth embodiment, after the LDPC tone mapper unit, the spatial stream is sent to the STBC unit to generate two space-time streams (each indicated by an arrow pointing from the STBC unit), and the two space-time streams are sent to the spatial mapper unit to be mapped to two or more transmit chains.

[0161] In the following paragraphs, a fifth embodiment of the present disclosure is described in which an enhanced frequency diversity scheme such as quad-carrier modulation (QCM) is applied to more than one SS without utilizing a reliability improvement method.

[0162] Fig.25A block diagram 2500 illustrating an enhanced frequency diversity scheme applied to two information bits across two spatial streams (SS1, SS2) of an OFDM symbol according to a fifth embodiment of the present disclosure is shown.

[0163] In the enhanced frequency diversity scheme according to the fifth embodiment, the QCM scheme is applied to more than one SS. In particular, the information bits from the first spatial stream (SS1) are modulated into four modulation symbols X mapped to four subcarriers (m, n1, n2, n3). 1k , X 1kDCM , -X 1kDCM , X 1kDCM Another information bit from the second spatial stream (SS2) is also modulated into four modulation symbols X mapped to the same four subcarriers (m, n1, n2, n3) 2k , X 2kDCM , -X 2kDCM , X 2kDCM The subcarriers (m, n1, n2, n3) are separated in frequency in the spatial streams by a large distance (e.g., by N SD / 4, where N SD is the number of data subcarriers per OFDM symbol or the number of data subcarriers within a subband (e.g., 20 / 40 / 80 MHz subband)

[0164] Advantageously, such a QCM scheme applied to more than one SS can provide spatial and frequency diversity at the same data rate as DCM with a single SS. However, it may not be applied to a 26-tone resource unit (RU) since the RU tone size cannot be divided into four equal units. Under such a scheme, different spatial streams can also be sent to different users, respectively. According to an embodiment, such a QCM scheme can also be integrated with any enhanced frequency diversity scheme described in various embodiments in the present disclosure to further obtain robustness and frequency diversity.

[0165] Fig.26 A transmission block diagram 2600 showing the processing of a data field by an enhanced frequency diversity scheme according to a fifth embodiment of the present disclosure is shown. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS=1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream. Specifically, in this fifth embodiment, the constellation mapper unit maps corresponding blocks of coded bits to four modulation symbols using BPSK and QCM schemes, and maps each modulation symbol to four OFDM subcarriers before sending the spatial stream to the LDPC tone mapper unit and the spatial mapper unit to map the spatial stream to three transmit chains.

[0166] In the following paragraphs, a sixth embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme (for example, the enhanced frequency diversity scheme described in the above-mentioned first to fifth embodiments) and a reliability improvement method are applied.

[0167] In particular, a time domain-based repetition reliability improvement method is described in this embodiment, and three different options / examples of time domain-based repetition can be applied: (1) direct time repetition, in which each OFDM symbol in the payload part of the PPDU is replicated one or more times before the next OFDM symbol; (2) OFDM symbol repetition with subcarrier permutation, in which each OFDM symbol in the payload part of the PPDU is replicated one or more times before the next OFDM symbol, and the subcarriers of the replicated symbols are permuted; and (3) OFDM symbol repetition with a subcarrier-time block coding scheme (CTBC), in which two or more OFDM symbols are grouped into OFDM symbol blocks, and each OFDM symbol block in the payload part of the PPDU is replicated one or more times before the next OFDM symbol block.

[0168] Fig. 27 An example payload portion 2700 of a PPDU according to the sixth embodiment of the present disclosure is shown, in which the time domain based repetition reliability improvement method under Option 1 is applied. Fig.28 FIG. 2 shows an example payload portion 2800 of a PPDU according to a sixth embodiment of the present disclosure, in which a time domain-based repetition reliability improvement method under Option 2 is applied. Fig. 27 and Fig.28 The number of repetitions is shown in 2 (N=2).

[0169] The payload portion 2700, 2800 of the PPDU may include multiple OFDM symbols (OFDM symbols 1, 2, ..., N). When the time domain based repetition reliability improvement method under Option 1 is applied, each OFDM symbol (OFDM symbol 1, 2, ..., N) within the payload portion 2700 is replicated once (N=2), so that there are two identical OFDM symbols before the next OFDM symbol along the payload portion. The replicated OFDM symbols (OFDM symbols 1, 2, ..., N) are allocated to be immediately after the original OFDM symbol and before the next OFDM symbol. This will result in a data rate reduction and adjustment to 1 / N, thereby improving the reliability of transmission, but only a power gain is obtained because the channel states for adjacent OFDM symbols are very similar.

[0170] When the time domain based repetition reliability improvement method under Option 2 is applied, upon duplication of the OFDM symbols (OFDM symbols 1, 2, ..., N) within the payload portion described in Option 1, the duplicated OFDM symbols (OFDM symbols XR, where X = 1, 2, ..., N) have their subcarriers permuted. Compared to Option 1, this will not only result in a data rate reduction and adjustment to 1 / N, thereby improving the reliability of transmission, but will also provide power and diversity gain.

[0171] Fig.29 A block diagram 2900 is shown showing a reliability improvement method under option 2 applied to an OFDM symbol (e.g., OFDM symbol N) in the payload portion of a PPDU according to a sixth embodiment of the present disclosure. The information bits are modulated into two modulation symbols X respectively mapped to two subcarriers (m, n) in a spatial stream of OFDM symbol n. 1k , X 1kDCM When the reliability improvement method under option 2 according to the sixth embodiment is applied, a repetition of an OFDM symbol is generated. In the OFDM symbol repetition (OFDM symbol n), the subcarriers are permuted so that the first modulation symbol in the repetition is mapped to the second subcarrier (n), and the second modulation symbol in the repetition is mapped to the first subcarrier (m) to be distinguished from the corresponding modulation symbol in the original OFDM symbol (OFDM symbol n).

[0172] Fig.30 An example payload portion 3000 of a PPDU according to the sixth embodiment of the present disclosure is shown, in which the time domain based repetition reliability improvement method under option 3 is applied. In this example, each adjacent OFDM symbol pair is grouped into an OFDM block for CTBC processing, and the number of OFDM symbol (block) repetitions is 2 (N=2). Therefore, each OFDM symbol (OFDM block) pair is mapped to four (or two pairs) of OFDM symbols.

[0173] In particular, the payload portion of the PPDU may include multiple OFDM symbols (OFDM symbols 1, 2, ..., N, N+1), and two adjacent OFDM symbols along the payload portion are grouped into an OFDM symbol block. When the time domain-based repetition reliability improvement method under Option 3 is applied, each OFDM symbol block within the payload portion (e.g., OFDM symbol 1 and OFDM symbol 2; and OFDM symbol N and OFDM symbol N+1) is replicated once (N=2), so that there are two identical OFDM symbol blocks before the next OFDM symbol block along the payload portion. The replicated OFDM symbol blocks (OFDM symbol 1R and OFDM symbol 2R; OFDM symbol NR and OFDM symbol N+1R) are allocated to be immediately after the original OFDM symbol block and before the next OFDM symbol block. This will not only result in a reduction in the data rate and adjustment to 1 / N, thereby improving the reliability of transmission, but will also provide power gain and increased robustness compared to Option 1.

[0174] CTBC is similar to STBC, but instead of mapping each SS into two spatial streams as in the case of STBC, in the case of CTBC each OFDM symbol pair (assuming an OFDM block includes two OFDM symbols) is mapped into 2N OFDM symbols, where N is the number of repetitions. CTBC processing operates on complex modulation symbols in a sequence of OFDM symbols. The same information bits from an OFDM symbol are mapped into more than one OFDM symbol. In order to add more frequency diversity, permutations within OFDM symbols can also be performed.

[0175] This will result in the data rate being reduced and adjusted to 1 / N, thereby improving the reliability of the transmission, but since the channel states for adjacent OFDM symbols are very similar, only power gain is obtained.

[0176] When the time domain based repetition reliability improvement method under Option 2 is applied, upon duplication of the OFDM symbols (OFDM symbols 1, 2, ..., N) within the payload portion described in Option 1, the duplicated OFDM symbols (OFDM symbols 1, 2, ..., N) have their subcarriers permuted. Compared to Option 1, this will not only result in a data rate reduction and adjustment to 1 / N, thereby improving the reliability of transmission, but will also provide power and diversity gains.

[0177] Fig.31 A block diagram 3100 illustrating a reliability improvement method under Option 3 applied to two information bits from spatial streams of two OFDM symbols to generate four OFDM symbols using CTBC according to a sixth embodiment of the present disclosure is shown.

[0178] The information bit X1 from the spatial stream (eg, the first spatial stream SS1) is modulated into a modulation symbol pair X mapped to the subcarriers (m1, m2) on the OFDM symbol 2n using the DCM scheme. 1k and X 1kDCM The DCM scheme is also used to modulate the adjacent information bits X2 from the spatial stream SS1 into modulation symbol pairs X mapped to the same subcarrier (m1, m2) on the adjacent OFDM symbol 2n+1. 2k and X 2kDCM .

[0179] The modulation symbol of SS1 from the OFDM symbol block including symbols 2n and 2n+1 is processed by the CTBC unit and replicated to generate two replicated OFDM symbols 2n+2, 2n+3, each having the same modulation symbol mapped to subcarriers (m1, m2). Fig.31 In the example shown, a permutation within the duplicate OFDM symbol is applied, resulting in a switch in the subcarrier mapping of the OFDM symbol. Thus, a second modulation symbol mapped to a second subcarrier in the original OFDM symbol is mapped to a first subcarrier in the duplicate OFDM symbol, and a first modulation symbol mapped to a first subcarrier in the original OFDM symbol is mapped to a second subcarrier in the duplicate OFDM symbol.

[0180] Furthermore, a permutation within the replicated OFDM symbol block (OFDM symbols 2n+2 and 2n+3) is applied, resulting in a switching of the OFDM symbol sequence within the replicated OFDM symbol block. Specifically, in the replicated OFDM symbol block including the first OFDM symbol 2n+2 and the second OFDM symbol 2n+3, the first OFDM symbol 2n+2 includes a modulation symbol X copied from the second OFDM symbol 2n+1 of the original OFDM symbol block. 2k , X 2kDCM , while the second OFDM symbol 2n+3 includes the modulation symbol X copied from the first OFDM symbol 2n of the original OFDM symbol block * 1k , -X * 1kDCM In addition, phase rotation or sign inversion is also applied to the modulation symbols of the replicated OFDM symbols (eg, X from the replicated OFDM symbols 2n+3 and 2n+2, respectively). * 1k , X * 2k ) to distinguish the corresponding modulation symbols from other OFDM symbols.

[0181] According to an embodiment, this DCM time-domain based repetition method may be applied to any enhanced frequency diversity scheme described in various embodiments of the present disclosure to further obtain robustness and frequency diversity.

[0182] A receiver STA that receives a PPDU with a preamble indicating OFDM symbol repetition applied should combine symbols from different OFDM symbol blocks after mapping before decoding and demodulating the PPDU to obtain power gain and robustness gain.

[0183] Fig.32 A transmission block diagram 3200 is shown, which illustrates the processing of the data field by the enhanced frequency diversity scheme to which the reliability improvement method is applied according to the sixth embodiment of the present disclosure. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream. The spatial stream is then sent to the spatial mapper unit to map the spatial stream to three transmit chains. Before the transmit chain is sent to the IDFT unit to convert the OFDM subcarriers on the transmit chain into time domain data for transmission, each transmit chain is also sent to a permutation unit to perform OFDM symbol replication and permutation of the replicated OFDM symbols, if necessary.

[0184] In the following paragraphs, a seventh embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme (e.g., the enhanced frequency diversity scheme described in the above-mentioned first to fifth embodiments) and another reliability improvement method, i.e., frequency replication of the payload part of the signal, are applied.

[0185] In particular, in the reliability improving method according to the seventh embodiment, when MCS15 or MCS14 is indicated, respectively, frequency duplication based on 1 / 2 or 1 / 4 of the payload part of the PPDU is applied.

[0186] Fig.33 An example 160 MHz PPDU 3300 to which 1 / 2-based frequency replication is applied according to the seventh embodiment of the present disclosure is shown. The 160 MHz PPDU 3300 includes a preamble part, an EHT-STF, an EHT-LTF, and a payload part 3302. In particular, in the 1 / 2-based frequency replication, the 160 MHz frequency segment is divided into two halves: a first half 80 MHz frequency segment and a second half 80 MHz frequency segment. The information bit X in the payload part 3302 of the 160 MHz PPDU 3300 is demodulated into two modulation symbols X and X. DCM, the two modulation symbols X and X DCM The two modulation symbols X and X are respectively mapped to two 40 MHz frequency segments in the first 80 MHz frequency segment in the 160 MHz frequency segment. DCM is replicated and mapped to two more 40MHz frequency segments within the second 80MHz frequency segment in the 160MHz frequency segment. This is similar to the EHT DUP transmission, where 1 / 2-based replication is applied when MCS15 is indicated. Note that if the RU tone size is less than 52-tones, 1 / 2-based frequency replication is not applied.

[0187] Fig.34 An example 160 MHz PPDU 3400 to which 1 / 4-based frequency replication is applied according to the seventh embodiment of the present disclosure is shown. The 160 MHz PPDU 3400 includes a preamble part, an EHT-STF, an EHT-LTF, and a payload part 3402. In particular, in the 1 / 4-based frequency replication, the 160 MHz frequency segment is divided into four quarters: a first quarter-divided 40 MHz frequency segment, a second quarter-divided 40 MHz frequency segment, a third quarter-divided 40 MHz frequency segment, and a fourth quarter-divided 40 MHz frequency segment. The information bit X in the payload part 3402 of the 160 MHz PPDU 3400 is demodulated into two modulation symbols X and X respectively mapped to two 20 MHz frequency segments within the first quarter-divided 40 MHz frequency segment in the 160 MHz frequency segment. DCM , the two modulation symbols X and X DCM The two 20 MHz frequency segments in each of the remaining second, third, and fourth quarter-divided 40 MHz frequency segments in the 160 MHz frequency segment are replicated and mapped. In addition, phase rotation or sign reversal can be applied to one or both of the replicated modulation symbols, as shown in the replicated modulation symbol 3404 in the third quarter-divided 40 MHz frequency segment.

[0188] Advantageously, under this reliability improvement method, adjustment to 1 / 2 data rate can be achieved, and further frequency diversity can be obtained. This reliability improvement method according to the seventh embodiment can also be applied together with any of the various reliability improvement methods described in the sixth and eighth embodiments of the present disclosure to further reduce the data rate and improve reliability.

[0189] Fig.35 A transmission block diagram 3500 showing the processing of the data field by an enhanced frequency diversity scheme according to the seventh embodiment of the present disclosure is shown. The transmitter processes similarly Figure 5The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream. Specifically, in the seventh embodiment, after the LDPC tone mapper unit, before the spatial stream is sent to the spatial mapper unit to be mapped onto the three transmit chains, the spatial stream is sent to the frequency domain replication unit to generate a replica of the modulated data in other frequency segments.

[0190] In the following paragraphs, an eighth embodiment of the present disclosure is described, in which an enhanced frequency diversity scheme (for example, the enhanced frequency diversity scheme described in the above-mentioned first to fifth embodiments) and another reliability improvement method through information block generation or code block concatenation scheme are applied.

[0191] In 802.11, LDPC is the coding scheme for the payload portion of the PPDU, and the LDPC encoder supports code block lengths of 648, 1296, and 1944. The LDPC encoder converts an information block of size k c = (i0, i1, ..., i k-1 ) is encoded into a codeword c of size n, c = (i0, i1, ..., i k-1 , p0, p1, …, p n-k-1 ), so that H×C T =0, where H is a (nk)×n parity check matrix.

[0192] There are two different options / examples to define the LDPC scheme for encoding information blocks according to the eighth embodiment: (1) defining an LDPC scheme with a rate of 1 / N by adding parity bits, where N is an integer greater than 2; (2) defining an LDPC scheme with a rate of K / N by changing the information block size, where K is the number of information bits and is an integer greater than 0; and N is a data rate adjustment factor and is an integer greater than 2.

[0193] Table 4 shows the LDPC information block lengths encoded under Option 1 according to the eighth embodiment for various codeword block lengths supported by the LDPC encoder when the coding rate is 1 / 4. In order to support LDPC with rate 1 / N, the corresponding prototype matrices P1, P2, P3 are defined for sizes The parity check matrix of .

[0194]

[0195] [Table 4]

[0196] Fig.36A first example codeword 3600 in the payload portion of a PPDU generated under option 2 according to the eighth embodiment of the present disclosure is shown. Fig.37 A second example codeword 3700 in the payload portion of a PPDU generated under option 2 according to the eighth embodiment of the present disclosure is shown. Fig.38 A third example codeword 3800 in the payload portion of a PPDU generated under option 2 according to the eighth embodiment of the present disclosure is shown.

[0197] refer to Fig.36 , (N / 2-K) bits of '0' padding bits are added to the information bits (K bits) to form an N / 2-bit information block. The same N / 2 bits of parity bits are generated from the information block at rate 1 / 2 to form a codeword. After generating the parity bits, the transmitter can send only the information bits with the parity bits, or send repeated information bits with the parity bits. In this example, the length of the codeword is the same as the current specification, so similar LDPC tone mapping can be used.

[0198] Alternatively, if Fig.37 As shown, no padding bits are added to the information bits (K bits), and the information block contains only information bits, while N bits of parity bits are added to form a codeword. In this example, the length of the codeword can be different from the current specification, and therefore a different LDPC tone mapping method can be used.

[0199] Alternatively, if Fig.38 As shown, instead of adding (N / 2-K) bits of padding bits, the information bits are repeated in the codeword with (N / 2-K) bits. The same N / 2 bits of parity bits are generated from the information block at rate 1 / 2 to form the codeword. In this example, the length of the codeword is the same as the current specification, so similar LDPC tone mapping can be used.

[0200] Additionally or alternatively, in addition to defining an LDPC scheme to encode an information block, the reliability improvement method according to the eighth embodiment can also be implemented by cascading N code blocks generated from the same information block. Although the code block is generated from the information block by adding parity check bits, different code blocks can be generated by encoding the same information block using different parity check matrices, and different code blocks are cascaded to improve transmission reliability.

[0201] Fig.39 FIG. 3 shows an example codeword 3900 including two concatenated code blocks generated from an information block according to an eighth embodiment of the present disclosure. The information block c includes information bits, and the LDPC encoder uses different parity check bits (p 1k and p 2k) Encode the information block into 2 code blocks at rate 1 / 2. Within each code block, the coding rate is 1 / 2, but in the entire payload part, the coding rate is 1 / 2N. In order to support rate concatenated LDPC codes, corresponding prototype matrices P1, P2, P3 different from the current prototype matrix are defined for codeword block lengths 648, 1296, 1944 at coding rate 1 / 2 for different parity check matrices.

[0202] With the reliability improvement method through the information block generation or code block concatenation scheme according to the eighth embodiment, a lower data rate than 802.11be can be achieved, and a new prototype and encoding mechanism are required.

[0203] Fig.40 A transmission block diagram 4000 is shown showing the processing of the data field by an enhanced frequency diversity scheme according to the eighth embodiment of the present disclosure. The transmitter processes similarly Figure 5 The transmitter processing shown uses a pre-FEC PHY padding unit, a scrambler unit, an LDPC encoder unit, a post-FEC PHY padding unit, a stream parser unit (N SS =1), a constellation mapper unit and an LDPC tone mapper unit to process a single spatial stream to process a single spatial stream. Specifically, in this eighth embodiment, the LDPC encoder unit is a special LDPC encoder unit that is capable of encoding an information block by adding parity bits and repeated information bits before sending the coded bits to the post-FECPHY padding unit.

[0204] As described above, embodiments of the present disclosure provide an advanced communication system, communication method, and communication device for subcarrier modulation across multiple spatial streams in a MIMO WLAN network.

[0205] The present disclosure can be implemented by software, hardware or software in collaboration with hardware. Each functional block used in the description of each of the above embodiments can be implemented in part or in whole by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled in part or in whole by the same LSI or a combination of LSIs. LSI can be formed as a chip alone, or a chip can be formed to include a part or all of the functional blocks. LSI can include data input and output coupled to it. According to the difference in integration, the LSI here can be referred to as IC, system on chip (SoC), system LSI, super LSI or ultra LSI. However, the technology for implementing integrated circuits is not limited to LSI, and can be implemented by using a dedicated circuit, a general processor or a dedicated processor. In addition, an FPGA (field programmable gate array) that can be programmed after LSI manufacturing or a reconfigurable processor that can reconfigure the connection and setting of the circuit unit arranged inside the LSI can be used. The present disclosure can be implemented as digital processing or analog processing. If, as a result of the advancement of semiconductor technology or other derivative technologies, future integrated circuit technology replaces LSIs, future integrated circuit technology can be used to integrate functional blocks. Biotechnology can also be applied.

[0206] The present disclosure may be implemented by any kind of equipment, device, or system having a communication function, which is referred to as a communication device.

[0207] Some non-limiting examples of such communication devices include phones (e.g., cellular (cell) phones, smart phones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telemedicine / telemedicine (remote health and medicine) devices, and vehicles providing communication capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0208] Communication devices are not limited to portable or movable, and may also include any kind of device, equipment, or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "things" in the network of the "Internet of Things (IoT)".

[0209] Communications may include exchanging data via, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0210] The communication apparatus may include a device such as a controller or a sensor coupled to a communication device that performs the communication functions described in the present disclosure. For example, the communication apparatus may include a controller or a sensor that generates a control signal or a data signal used by the communication device that performs the communication functions of the communication apparatus.

[0211] Communications devices may also include infrastructure equipment such as base stations, access points, and any other device, equipment, or system that communicates with or controls devices such as those in the above non-limiting examples.

[0212] It shall be understood that, although some properties of the various embodiments have been described with reference to an apparatus, corresponding properties also apply to the method of the various embodiments, and vice versa.

[0213] It will be appreciated by those skilled in the art that many changes and / or modifications may be made to the disclosure shown in the specific embodiments without departing from the spirit or scope of the disclosure as broadly described. Therefore, the present embodiments are to be considered in all aspects as illustrative and not restrictive.

Claims

1. A first communication device, comprising: circuitry configured to set first information indicating whether to apply mapping from two or more modulation symbols modulated by information bits of a signal to two or more subcarriers across two or more spatial streams of an orthogonal frequency division multiplexing (OFDM) symbol, and second information indicating whether to apply data rate adjustment to the signal; as well as A transmitter transmits the signal utilizing the mapping of the two or more modulation symbols across the two or more spatial streams and / or the data rate adjustment, the signal comprising the first information and the second information.

2. The first communication device according to claim 1, wherein: The circuit is also configured to: compare the modulation coding scheme and the number of spatial streams N of the signal SS A signal field related to one or both of the first information and the second information is set to include one or both of the first information and the second information.

3. The first communication device according to claim 1, wherein: The mapping includes mapping two modulation symbols of the two or more modulation symbols modulated from the information bits to a first subcarrier of the two or more subcarriers in a first spatial stream of the two or more spatial streams of the OFDM symbol and a second subcarrier of the two or more subcarriers in a second spatial stream of the two or more spatial streams, respectively.

4. The first communication device according to claim 1, wherein: The mapping includes identical mapping from two of the two or more modulation symbols modulated by the information bits to the two or more subcarriers in each of the two or more spatial streams.

5. The first communication device according to claim 1, wherein: The mapping includes: mapping two of the two or more modulation symbols modulated from the first information bit of the signal to the first spatial stream of the two or more spatial streams of the OFDM symbol and the two or more subcarriers in the second spatial stream of the two or more spatial streams of the adjacent OFDM symbol, and mapping two of the two or more modulation symbols modulated from the second information bit of the signal to the second spatial stream of the two or more spatial streams of the OFDM symbol and the two or more subcarriers in the first spatial stream of the two or more spatial streams of the adjacent OFDM symbol; and the transmitter transmits the signal through the first spatial stream and the second spatial stream of the OFDM symbol and the adjacent OFDM symbol.

6. The first communication device according to claim 4, wherein: The mapping further includes phase rotation, sign reversal, or conjugation of one of the two or more modulation symbols mapped to one of the two or more subcarriers in one of the two or more spatial streams of the OFDM symbol.

7. The first communication device according to any one of claims 4, wherein: The mapping includes switching two of the two or more modulation symbols mapped to two of the two or more subcarriers in one of the two or more spatial streams.

8. The first communication device according to claim 1, wherein: The data rate adjustment corresponds to a copy of the OFDM symbol in a payload portion of the signal; and the transmitter transmits the signal including the OFDM symbol in the payload portion and one or more copies of OFDM symbols immediately adjacent to the OFDM symbol.

9. The first communication device according to claim 1, wherein: The data rate adjustment corresponds to a copy of the OFDM symbol block in the payload portion of the signal; and the transmitter sends the signal including the OFDM symbol block in the payload portion and one or more copies of the OFDM symbol blocks adjacent to the OFDM symbol block, wherein the OFDM symbol block includes the OFDM symbol and one or more adjacent OFDM symbols.

10. The first communication device according to claim 8, wherein: The data rate adjustment includes switching two of the two or more modulation symbols mapped to two of the two or more subcarriers in one of the one or more copies of the OFDM symbol.

11. The first communication device according to any one of claims 8, wherein: The mapping also includes phase rotation, sign reversal, or conjugation of one of the two or more modulation symbols mapped to one of the two or more subcarriers in one of the two or more spatial streams in one of the one or more copies of the OFDM symbol.

12. The first communication device according to claim 2, wherein: The data rate adjustment corresponds to a frequency replication of the payload portion of the signal; and the circuit is also configured to: generate the signal comprising the information bits in a first frequency segment in the payload portion of the signal and one or more replications of the information bits in one or more second frequency segments; and set the first information, the first information indicating whether mapping of two or more modulation symbols modulated from the information bits of the signal and the one or more replications of the information bits to two or more subcarriers is applied across the two or more spatial streams of the OFDM symbol.

13. The first communication device according to claim 12, wherein: The signal field related to the modulation and coding scheme indicates a number of copies of the one or more copies of the information bits in the one or more second frequency segments of the payload portion.

14. The first communication device according to claim 1, wherein: The second information includes a coding rate, the data rate adjustment corresponds to the formation of an information bit block in the payload part of the signal, and the information bit block includes a plurality of the data bits, wherein the circuit is further configured to: generate the signal including the information bit block and one or more parity bits in the payload part of the signal; and set the first information, the first information indicating whether mapping of two or more modulation symbols modulated from the information bit block is applied across the two or more spatial streams of the OFDM symbol, wherein the number of the one or more parity bits depends on the coding rate.

15. The first communication device according to claim 14, wherein: The information bit block includes one of: (i) one or more padding bits, and (ii) one or more repetitions of the plurality of data bits, wherein the number of the padding bits and the number of repetitions of the plurality of data bits both depend on the coding rate.

16. A second communication device, comprising: a receiver receiving a signal comprising first information indicating whether to apply mapping from two or more modulation symbols modulated by information bits of the signal to two or more subcarriers across two or more spatial streams of an OFDM symbol, and second information indicating whether to apply data rate adjustment to the signal; as well as A circuit is configured to decode and demodulate the signal to obtain information of the information bits mapped to the two or more spatial streams.

17. The second communication device according to claim 16, wherein: The signal includes the modulation coding scheme and the number of spatial streams N SS A signal field related to one or both of the first information and the second information, the signal field including either or both of the first information and the second information.

18. A communication method implemented by a first communication device, comprising: Setting first information and second information, the first information indicating whether mapping from two or more modulation symbols modulated by information bits of a signal to two or more subcarriers is applied across two or more spatial streams of an OFDM symbol, and the second information indicating whether data rate adjustment is applied to the signal; as well as The signal is transmitted utilizing the mapping of the two or more modulation symbols across the two or more spatial streams and / or the data rate adjustment, the signal comprising the first information and the second information.

19. A communication method implemented by a second communication device, comprising: receiving a signal including first information indicating whether to apply mapping from two or more modulation symbols modulated from information bits of the signal to two or more subcarriers across two or more spatial streams of an OFDM symbol and second information indicating whether to apply data rate adjustment to the signal; as well as The signal is decoded and demodulated to obtain information of the information bits mapped to the two or more spatial streams.

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