Low power indoor wireless network data transmission

Abstract

A method and system includes encoding a source word to be transmitted in a data unit from a source station in a wireless network, generating a first OFDM symbol carrying a data segment corresponding to an encoded bit of the source word, replicating the first OFDM symbol, and generating a second OFDM symbol carrying a data segment corresponding to the encoded bit of the source word. To generate a second OFDM symbol that is a linear phase rotation copy of the first OFDM symbol; and transmitting the data unit including the first OFDM symbol and the second OFDM symbol.

Description

[0001] This application is a divisional application. The application number of the original application is 202080106007.5, and the original application date is October 10, 2020. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to air interface technology, and in particular to a low-power data transmission method and system. Background Art

[0003] The IEEE 802.11 standard is a set of standards for implementing wireless fidelity (Wi-Fi). TM ) is a standard for media access control (MAC) and physical layer (PHY) specifications for wireless local area network (WLAN) communications. The 802.11 standard has undergone steady evolution and continues to be developed to meet the growing demand for enhanced throughput, reduced latency and jitter, improved reliability, and greater energy efficiency driven by new and emerging applications including virtual or augmented reality, immersive gaming, remote office support, and cloud computing.

[0004] IEEE 802.11be (extremely high throughput, EHT) is currently being developed by the IEEE 802.11 task group TGbe and will be the next major IEEE 802.11 amendment (currently IEEE draft P802.11ax_D6.0) to define the next generation of Wi-Fi after IEEE 802.11ax (high efficiency, HE). The modulation and coding scheme (MCS) defined in HE will be reused in EHT. The design of EHT will utilize the 6GHz band opened by the Federal Communications Commission (FCC) for unlicensed use.

[0005] The entire 6 GHz band will be available for unlicensed low power indoor (LPI) operation without the need for automated frequency coordination (AFC) to control access, providing the potential for the deployment of next-generation Wi-Fi to use channels with bandwidths up to 320 MHz. Since other licensed incumbent services, such as fixed and mobile services and fixed satellite services, also operate in the 6 GHz band, the FCC has defined rules for unlicensed LPI operation to prevent harmful interference to incumbent services. These rules limit LPI to indoor operation only, require contention-based agreements, and enforce low-power operation.

[0006] Enabling low-power indoor (LPI) devices to operate across the entire 6 GHz band is fundamental to the success of the 6 GHz process. Due to their low power and indoor operation, these devices do not require automated frequency coordination (AFC) and can operate in all four sub-bands while protecting licensed operations.

[0007] However, the effective isotropically radiated power (EIRP) power spectral density (PSD) requirements for LPI stations such as LPI access points (APs) and LPI non-AP stations (STAs) in the 6GHz band are much more stringent than those in the 2.4GHz and 5GHz bands. For example, the maximum EIRP PSD supported by LPI APs in the 6GHz band is 5dBm / MHz, while the maximum EIRP PSD in the 5GHz band is 17dBm / MHz; the maximum EIRP PSD supported by LPI STAs in the 6GHz band is -1dBm / MHz, while the maximum EIRP PSD in the 5GHz band is 11dBm / MHz. Therefore, compared with LPI APs and STAs in the 5GHz band, LPI APs and STAs in the 6GHz band have a much shorter range (i.e., about one-fourth) and a smaller coverage area.

[0008] LPI devices and transmission technologies are needed to alleviate the above-mentioned range and coverage issues arising from the limitations of 6GHz LPI Wi-Fi. Summary of the invention

[0009] According to a first exemplary aspect, a method is disclosed, comprising: encoding a source word to be sent in a data unit from a source station in a wireless network; generating a first orthogonal frequency division multiplexing (OFDM) symbol, the first OFDM symbol carrying a data segment corresponding to the encoded bits of the source word; replicating the first OFDM symbol to generate a second OFDM symbol that is a linear phase rotated copy of the first OFDM symbol; and sending the data unit including the first OFDM symbol and the second OFDM symbol.

[0010] According to an exemplary embodiment of the first exemplary aspect, the method includes: mapping the coded bits to a first modulation symbol set and a second modulation symbol set; wherein generating the first OFDM symbol includes: mapping the first modulation symbol set to a first frequency subcarrier set corresponding to the first OFDM symbol, mapping the second modulation symbol set to a second frequency subcarrier set corresponding to the first OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers.

[0011] In an exemplary embodiment of one or more of the above aspects, mapping the coded bits comprises applying a phase rotation to the second set of modulation symbols relative to the first set of modulation symbols.

[0012] In an exemplary embodiment of one or more of the above aspects, the method includes: copying the first modulation symbol set and the second modulation symbol set to provide a third modulation symbol set and a fourth modulation symbol set, wherein all four modulation symbol sets each constitute the data segment respectively; generating the first OFDM symbol includes: before performing the inverse fast Fourier transform operation, mapping the third modulation symbol set to a third frequency subcarrier set corresponding to the first OFDM symbol, and mapping the fourth modulation symbol set to a fourth frequency subcarrier set corresponding to the first OFDM symbol.

[0013] According to a second exemplary aspect, a method is disclosed, comprising: encoding a source word to provide a first codeword, the first codeword comprising information bits of the source word and a first set of parity bits; generating a first OFDM symbol, the first OFDM symbol carrying a first data segment corresponding to the information bits of the source word and the first set of parity bits; permuting the information bits of the source word to provide a permuted information bit set; encoding the permuted information bit set of the source word to provide a second codeword, the second codeword comprising the permuted information bit set and a second set of parity bits of the source word; generating a second OFDM symbol, the second OFDM symbol carrying a second data segment corresponding to the information bits of the source word and the second set of parity bits; and sending a data unit comprising the first OFDM symbol and the second OFDM symbol in a wireless network.

[0014] According to an exemplary embodiment of the second aspect, the method includes: mapping the bits of the first data segment to two corresponding modulation symbol sets, wherein generating the first OFDM symbol includes: mapping one modulation symbol set of the modulation symbol sets to a first frequency subcarrier set of the first OFDM symbol, mapping the other modulation symbol set to a second frequency subcarrier set of the first OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers of the first OFDM symbol; mapping the bits of the second data segment to a first modulation symbol set and a second modulation symbol set, wherein generating the second OFDM symbol includes: mapping the first modulation symbol set to a first frequency subcarrier set of the second OFDM symbol, mapping the second modulation symbol set to a second frequency subcarrier set of the second OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers of the second OFDM symbol.

[0015] According to a third exemplary aspect, a method is disclosed, comprising: encoding a source word to provide a first codeword, the first codeword comprising information bits of the source word and a first set of parity bits; mapping a first data segment corresponding to the information bits and the first set of parity bits of the source word to a first set of modulation symbols and a second set of modulation symbols; permuting the information bits of the source word to provide a permuted set of information bits; encoding the permuted set of information bits to provide a second codeword, the second codeword comprising the permuted information bits and the second set of parity bits of the source word; mapping a second data segment corresponding to the information bits and the second set of parity bits of the source word to a third set of modulation symbols and a fourth set of modulation symbols; Modulation symbol sets, wherein the first modulation symbol set, the second modulation symbol set, the third modulation symbol set and the fourth modulation symbol set all carry the same information bits of the source word; mapping the first modulation symbol set to a first frequency subcarrier set of an OFDM symbol, mapping the second modulation symbol set to a second frequency subcarrier set of the OFDM symbol, mapping the third modulation symbol set to a third frequency subcarrier set of the OFDM symbol, and mapping the fourth modulation symbol set to a fourth frequency subcarrier set of the OFDM symbol; performing an inverse fast Fourier transform operation on the frequency subcarriers to generate the OFDM symbols; and sending a data unit including the OFDM symbols in a wireless network.

[0016] According to an exemplary embodiment of the second aspect and the third aspect, the first codeword is a first low density parity check (LDPC) codeword that conforms to a first parity check matrix, and the second codeword is a second LDPC codeword that conforms to a second parity check matrix, wherein the second parity check matrix is ​​derived by permuting the positions of columns corresponding to information bits in the first parity check matrix and copying a portion of the first parity check matrix corresponding to parity check bits.

[0017] According to a fourth exemplary aspect, a method is disclosed, comprising: generating a first low-density parity-check (LPDC) codeword of a source word for a first transmission, the first LDPC codeword comprising information bits of the source word and a first set of parity-check bits; permuting the information bits of the source word; and generating a second LDPC codeword for retransmission, the second LDPC codeword comprising permuted information bits of the source word and a second set of parity-check bits corresponding to the permuted information bits, wherein the first LDPC codeword conforms to a first parity-check matrix, the second LDPC codeword conforms to a second parity-check matrix, and the second parity-check matrix is ​​derived by permuting the positions of columns corresponding to information bits in the first parity-check matrix and copying a portion of the first parity-check matrix corresponding to parity bits.

[0018] According to exemplary embodiments of one or more of the above aspects, permuting the information bits of the source word is performed according to a predefined permutation map.

[0019] According to another exemplary aspect, a method of encoding a physical layer (PHY) protocol data unit (PPDU) for low power indoor (LPI) wireless communication is disclosed, the method comprising: encoding a first set of information bits of a first universal signaling field (U-SIG 1) in a preamble of the PPDU using binary phase shift keying (BPSK), the first set of information bits comprising information about a payload of the PPDU; encoding a second set of information bits of a second universal signaling field (U-SIG 2) in the preamble of the PPDU using quadrature binary phase shift keying (QBPSK), the second set of information bits comprising further information about the payload of the PPDU; encoding the first set of information bits of a third universal signaling field (RU-SIG 1) in the preamble of the PPDU using QBPSK; encoding the second set of information bits of a fourth universal signaling field (RU-SIG 2) in the preamble of the PPDU using BPSK; and transmitting the PPDU in a wireless network.

[0020] In some examples, the BPSK-encoded first set of information bits is carried in the first OFDM symbol, the QBPSK-encoded second set of information bits is carried in a second OFDM symbol adjacent to the first OFDM symbol, the QBPSK-encoded first set of information bits is carried in a third OFDM symbol adjacent to the second OFDM symbol, and the BPSK-encoded fourth set of information bits is carried in a fourth OFDM symbol adjacent to the third OFDM symbol.

[0021] According to another exemplary aspect, a method is disclosed, comprising: assembling a preamble of a physical layer (PHY) protocol data unit (PPDU) for low power indoor (LPI) wireless communication, the preamble comprising: a first universal signaling field (U-SIG 1), carrying a BPSK-encoded first set of information bits including information about a payload of the PPDU; a second universal signaling field (U-SIG 2), carrying a BPSK-encoded second set of information bits including further information about the payload of the PPDU; a third universal signaling field (RU-SIG 1), carrying a copy of the BPSK-encoded first set of information bits; a fourth universal signaling field (RU-SIG 2), carrying a copy of the BPSK-encoded second set of information bits; and sending the PPDU including the assembled preamble in a wireless network.

[0022] In some examples, the common signaling fields are each carried in a corresponding OFDM symbol.

[0023] In some examples, the preamble is a greenfield preamble that does not include any legacy fields.

[0024] According to another exemplary aspect, a wireless transmission station is disclosed, for performing the method of any one of the above aspects.

[0025] According to another exemplary aspect, a non-transitory computer-readable medium storing instructions for configuring a wireless transmission station to perform the method of any of the above aspects is disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Reference will now be made by way of example to the accompanying drawings which show exemplary embodiments of the present application, in which:

[0027] Figure 1 is a block diagram illustrating an exemplary communication network according to one implementation of the present disclosure.

[0028] Figure 2 It is a diagram showing a method for implementing the present disclosure. Figure 1 A block diagram of an exemplary processing system for a station in a communication network of FIG.

[0029] Figure 3 Examples of data units that may be used to carry information in a communications network are shown.

[0030] Figure 4 is an example of an OFDM symbol generator that may be used in a source station of a communication network according to an exemplary embodiment.

[0031] Figure 5 It is shown by Figure 4A frequency-time diagram of an example of OFDM symbols generated by an OFDM symbol generator.

[0032] Figure 6 is an example of an OFDM symbol generator that may be used in a source station of a communication network according to further exemplary embodiments.

[0033] Figure 7 It is shown by Figure 6 A frequency-time diagram of an example of OFDM symbols generated by an OFDM symbol generator.

[0034] Figure 8 is an example of an OFDM symbol generator that may be used in a source station of a communication network according to another exemplary embodiment.

[0035] Fig. 9 It is shown by Figure 8 A frequency-time diagram of an example of OFDM symbols generated by an OFDM symbol generator.

[0036] Fig. 10A is a block diagram illustrating an encoding process according to an exemplary embodiment.

[0037] Fig. 10B An example of a basic parity check matrix (PCM) Hb(4×24) for a rate 5 / 6 LDPC code where n=1944 and Z=81 is shown, along with an illustrative cyclic shifted version for the simplified case of the identity matrix and Z=4.

[0038] Fig.11 is a block diagram illustrating a plurality of LDPC encoding processes according to an exemplary embodiment.

[0039] Fig.12 A table is shown which defines a permutation mapping set s corresponding to the basic PCM H of a rate 5 / 6 LDPC code. b , where n=1944 and Z=81.

[0040] Fig.13 shows the original basic PCM H b (0) and extended basic PCM H b Example of (1).

[0041] Fig.14 is an example of an OFDM symbol generator that may be used in a source station of a communication network according to an exemplary embodiment.

[0042] Fig.15 It is shown by Fig.14A frequency-time diagram of an example of OFDM symbols generated by an OFDM symbol generator.

[0043] Fig.16 is an example of an OFDM symbol generator that may be used in a source station of a communication network according to an exemplary embodiment.

[0044] Fig.17 It is shown by Fig.16 A frequency-time diagram of an example of OFDM symbols generated by an OFDM symbol generator.

[0045] Fig.18 A method according to an exemplary embodiment is shown which can be used in Figure 1 An example of a data unit that carries information in a communications network.

[0046] Fig.19 A method according to an exemplary embodiment is shown which can be used in Figure 1 Another example of a data unit that carries information in a communications network.

[0047] The same reference numerals are used throughout the drawings to denote the same elements and features.While aspects of the invention will be described in conjunction with the illustrated embodiments, it will be understood that they are not intended to limit the invention to these embodiments. DETAILED DESCRIPTION

[0048] The present disclosure teaches methods, devices, and systems for transmitting data in an LPI wireless network. As described above, the regulatory regimes that will be applied to next-generation LPI WLAN systems, including, for example, next-generation LPI Wi-Fi systems operating in the 6 GHz band, will allow for large potential bandwidths but impose regulatory restrictions that effectively limit the power and range of devices used in such systems. Exemplary embodiments are disclosed that are intended to achieve optimized device and transmission performance in light of these regulatory constraints.

[0049] Will refer to Figure 1 and Figure 2 An example of a communication network 100 is described in which the devices and methods described below may operate. Figure 1 As shown, network 100 includes a plurality of communication devices, which may include fixed, portable, and mobile devices (referred to as stations). Figure 1 The example shows a single fixed access point (AP) station 102 and multiple non-AP stations (STAs) 104 that may be portable or mobile. In at least some examples, network 100 is a next-generation LPI Wi-Fi compatible network that operates according to one or more protocols in the 802.11 standard, such as the protocols specified in IEEE 802.11be (EHT). WLAN 106 can be used to support OFDM transmission technology.

[0050] Each STA 104 may be a laptop, a personal computer (PC), a personal digital assistant (PDA), a Wi-Fi phone, a wireless transmit / receive unit (WTRU), a mobile station (MS), a mobile terminal, a smart phone, a mobile phone, a sensor, an Internet of Things (IOT) device, or other wirelessly enabled computing or mobile device. In some embodiments, the STA 104 may be an LPI-enabled device that may operate indoors, where signal transmission may be attenuated by indoor structures (e.g., walls). In some embodiments, the STA 104 includes a machine that is capable of sending, receiving, or sending and receiving data in the WLAN 106, but performs a primary function other than communication. In some embodiments, the machine includes a device or equipment having a component that sends and / or receives data through the network 100, but such a device or equipment is not typically operated by a user for the primary purpose of communication.

[0051] The AP 102 may include a bidirectional network access interface that serves as a wireless transmission and / or reception point for the STAs 104 in the network 100. The AP 102 may be connected to a backhaul network 108 that enables the AP 102 to exchange data with other remote networks (e.g., including the Internet), nodes, APs, and devices (not shown). The AP 102 may support communication with each STA 104 over the unlicensed RF wireless medium 106 by establishing uplink and downlink communication channels with each STA 104, such as Figure 1 In some examples, STAs 104 may communicate with each other. Communications in network 100 may be unscheduled, may be scheduled by AP 102 or another scheduling or management entity in network 100, or may be a combination of scheduled and unscheduled communications.

[0052] Figure 2 Shows that it can be used as Figure 1 102 or STA 104. The wireless communication apparatus includes at least one processing unit 110, at least one transmitter 112, at least one receiver 114, one or more antennas 116, at least one non-transitory storage unit 118, and one or more input / output (I / O) devices or interfaces 120.

[0053] The processing unit 110 implements various processing operations of the AP 102 or the receiving STA 104, such as signal encoding, data processing, power control, input / output processing, or any other function. The processing unit 110 may also be used to implement some or all of the functions and / or embodiments described herein. Each processing unit 110 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 110 may include a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, or an application-specific integrated circuit. The processing unit 110 may be used to: generate a wireless signal based on input data received through an input terminal (via the I / O interface 120) to be sent through the transmitter 112; or process a wireless signal received from the receiver 114. In an exemplary embodiment, the processing unit 110 may be used to generate an OFDM or orthogonal frequency division multiple access (OFDMA) signal suitable for transmission by, for example, performing an inverse fast Fourier transform (IFFT) or an inverse discrete Fourier transform (IDFT) or any other suitable processing technique. The processing unit 110 may also be used to process a received OFDM signal or OFDMA signal by, for example, performing a fast Fourier transform (FFT) or a discrete Fourier transform (DFT) or any other suitable processing technique. In some embodiments, the processing unit 110 may be used to detect the presence of an OFDM signal or OFDMA signal by performing correlation or cross-correlation to detect a preamble. The preamble may be part of a predetermined frame structure for Wi-Fi communications. Although a single instance of the processing unit 110 is shown, it should be understood that multiple instances of the processing unit 110 may be present in each wireless communication device. For example, there may be at least one processing unit for processing output signals to be transmitted by the transmitter 112 , and at least one processing unit for processing input signals from the receiver 114 .

[0054] The transmitter 112 may include any suitable structure for generating a signal for wireless or wired transmission. Each receiver 114 may include any suitable structure for processing a signal received wirelessly or wired. Each transmitter 112 and receiver 114 may include associated amplification and modulation / demodulation circuits. Although shown as separate components, at least one transmitter 112 and at least one receiver 114 may be combined into a single transceiver. Each antenna 116 may include any suitable structure for transmitting and / or receiving wireless or wired signals. Although the common antenna 116 is shown here as coupled to the transmitter 112 and the receiver 114, one or more antennas 116 may be coupled to one or more transmitters 112, and one or more separate antennas 116 may be coupled to one or more receivers 114. In some examples, one or more antennas 116 may be an antenna array, which may be used for beamforming and beam steering operations. Each non-transitory storage unit 118 may include any suitable volatile and / or non-volatile storage and retrieval device. Any suitable type of memory may be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, etc. The non-transitory memory storage unit 118 may store instructions and data used, generated, or collected by the AP 102 or STA 104. For example, the non-transitory storage unit 118 may store software instructions or modules executed by the processing unit 110, which are used to implement some or all of the functions and / or embodiments described herein.

[0055] I / O interface 120 may allow interaction with users or other devices in a network. I / O interface 120 includes any suitable structure for providing information to or receiving information from a user, including a network communication interface.

[0056] In some embodiments, AP 102 and STA 104 can be used to communicate on various wireless spectrums, such as 20MHz, 40MHz or 80MHz, 80+80MHz, 160MHz, 160+160MHz, 320MHz, 320+320MHz, 480MHz (e.g., 160+160+160MHz), and 640MHz in the 2.4GHz, 5GHz, and 6GHz bands. According to some wireless standards, such as IEEE 802.11ax, an OFDMA channel is subdivided into multiple resource units (RUs), where each RU consists of a set of consecutive subcarriers defined in the frequency domain. In IEEE 802.11ax, RUs are defined based on RU size, such as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, and 2×996-tone RUs. Although reference is made to IEEE 802.11ax, it should be noted that techniques or mechanisms according to some implementations of the present disclosure may be used in conjunction with other standards, including future generations of IEEE 802.11, such as the EHT standard or different standards.

[0057] In the wireless network 100, wireless communication devices such as AP 102 and STA 104 communicate with each other through various well-defined frame structures. Frame structures, such as PPDU, can be composed of Figure 2 The processing unit 110 of the wireless communication device shown is generated. In some embodiments, the frame structure can be configurable to have the same bandwidth as the channel. The frame structure can be in the form of a PPDU, and the PPDU can include a frame preamble code part and a payload part. In some embodiments, there may be different types of PPDUs, which may have different fields and different PHY layers and / or different MAC layers. For example, single user (SU) PPDU, multi-user (MU) PPDU, LPIPPDU, long-range (LR) SU PPDU, trigger-based (TB) PPDU.

[0058] For IEEE 802.11be, a wide BW LPI LR PPDU (LPI Long Range PPDU) operating in the 6 GHz band has been proposed to at least partially address the short range and reduced coverage caused by the proposed EIRP PSD requirements for LPI devices. For example, a wide BW may be defined as having a BW equal to or greater than 80 MHz. Figure 3An example of a proposed EHT PPDU frame 200 that can be used for wide BW LPI LR communication in an 80 MHz channel is shown. The EHT PPDU frame 200 can be generated and sent by a source station (e.g., AP 102) and received and decoded by a destination station (e.g., STA 104). The EHT PPDU frame 200 can include a preamble portion 202 followed by a payload portion 204.

[0059] As shown, the preamble portion 202 may include a legacy preamble portion 206 and an EHT preamble portion 210. The legacy preamble portion 206 first established in the IEEE 802.11a standard (hereinafter referred to as the 11a standard) may allow backward compatibility and coexistence with traditional IEEE 802.11 devices. The legacy preamble portion 206 may include two ODFM symbols, which carry a legacy short training field (L-STF) (not shown) and a legacy long training field (L-LTF) (not shown) for frame detection and receiver synchronization, respectively. The legacy preamble portion 206 may be decoded by a traditional Wi-Fi device. For 802.11 standards after IEEE 802.11n, the MCS and frame length indicated in the L-SIG may be token placeholders. The real values ​​of MCS, frame size, and other parameters may be sent by other symbols according to a specific version. For example, in IEEE 11ax, the preamble 202 repeats the L-SIG as the RL-SIG and indicates a length equal to one or two modulo three. Second, the High Efficiency (HE) signaling field includes two OFDM symbols. The first OFDM symbol is modulated with QBPSK, while the second OFDM symbol is modulated with BPSK or QBPSK. The result of the modulo operation combined with the BPSK / QBPSK selection determines one of the four 11ax frame types.

[0060] In the illustrated embodiment, the EHT preamble portion 210 includes a universal signaling field (U-SIG) 212, an EHT-SIG field 214, an EHT-STF field 216, and an EHT-LTF field 218. In some embodiments, the frame format of the 11be standard and higher standards uses a double OFDM symbol long universal SIG (U-SIG) 212, which may include information bits about the payload portion 204. The adoption of the U-SIG 212 may provide forward compatibility with future IEEE 802.11 standards. It will be appreciated that the U-SIG 212, being two symbols long, may have a maximum bit carrying capacity of 42 bits. The U-SIG 212 is similar to the HE-SIG-A in the 11ax PPDU in that it may include version-independent information followed by version-dependent information. The version-independent information may include a 3-bit PHY format identifier, a 1-bit uplink (UL) / downlink (DL) flag, at least 6 bits of basic service set (BSS) color, at least 7 bits of transmission (TX) opportunity (TXOP) duration, bandwidth, etc. The version-dependent information may include information such as the number of EHT long training field symbols, the mid-amble period, and the space-time block coding flag. The U-SIG 212 may also be encoded with a separate error detection code (i.e., a cyclic redundancy check (CRC) code of at least 4 bits) and 6 tail bits. In addition, the presence of the U-SIG 204 and other symbols such as the L-SIG may allow the receiver to distinguish between 11be frames and 11ax frames. For example, for 11be EHT transmission, the L_LENGTH field in the L-SIG may be set so that the L_LENGTH modulo 3 is equal to 1, and the bit B0 of the U-SIG 212 may be set to 0, which the receiver may recognize as an EHT PPDU. In some embodiments, the U-SIG 212 may be encoded with MCS0 at a code rate of R=1 / 2, interleaved, and mapped to a binary phase shift keying (BPSK) constellation.

[0061] In some exemplary embodiments, the EHT-SIG field 214 may store information in addition to the information stored in the U-SIG field 212. The EHT-SIG field 214 may adopt its own MCS, which is different from the data MCS and may occupy a variable number of ODFM symbols, which may be indicated in the U-SIG field 212. In an exemplary embodiment, the EHT-SIG field 214 may include a common field and a user-specific field. The common field may include information about MCS, number of spatial streams (NSS), coding, guard interval duration, and RU allocation, etc. The user-specific field may exist in a multi-user (MU) frame and carry dedicated information for a single STA. For example, the EHT-SIG field 214 may include a subfield for each STA in a plurality of STAs. Each STA subfield may include a subfield that specifies the following: a STA-ID that uniquely identifies the target STA, a RU assigned to the target STA, and an MCS used by each RU in the corresponding RU assigned to the target STA (e.g., MCS (i) of RU i; MCS (j) of RU j). In an exemplary embodiment, the MCS subfield may be populated with an MCS index value of an MCS mapped to a specified MCS applied to the RU.

[0062] In some exemplary embodiments, the EHT short training field (STF) 216 and the EHT long training field (LTF) 218 ​​may follow the EHT-SIG field 214 and may be used to define the time and frequency tuning of MIMO / OFDMA. In some embodiments, the EHT-STF 216 and the EHT-LTF 218 are longer variants of the STF and LTF from the 11ax standard, which may enable extended range and better channel estimation. In some wide BW embodiments where the channel BW is 80 MHz or greater, the EHT-STF field 216 and the EHT-LTF field 218 are repeated every 20 MHz, such as Figure 2 In some embodiments, the phase of each 20 MHz copy of the EHT-STF 216 and the EHT-LTF 218 may be rotated to reduce the peak-to-average power ratio and enhance the correlation performance.

[0063] In some exemplary embodiments, when a wide bandwidth is used, the legacy preamble portion 206, the U-SIG field 212, and the EHT-SIG field 214 may be replicated every 20 MHz. Thus, as shown, in an 80 MHz channel, the legacy preamble 206 is repeated four times, becoming legacy preambles 206A, 206B, 206C, and 206D; U-SIG fields 212A, 212B, 212C, and 212D; and EHT-SIG fields 214A, 214B, 214C, and 214D.

[0064] The payload portion 204 may include one or more fields in the form of an OFDM symbol, which includes a physical layer convergence protocol (PLCP) service data unit (PSDU), which is a data unit sent down from the MAC layer for transmission on the wireless medium 106.

[0065] Dual carrier modulation (DCM) is a technique adopted in 802.11ax [802.11axD6.0] to improve link budget. DCM modulates the same information on a pair of subcarriers. DCM is considered in 802.11ax to improve link bit error rate performance, spectrum efficiency and data rate by half by using frequency domain diversity gain. In 802.11 amendments using OFDM, the subcarrier spacing is defined to be fixed to 312.5kHz. Therefore, the duration of each OFDM symbol with a given cyclic prefix duration is also fixed. For example, if the duration of the cyclic prefix is ​​0.8μs, the duration of the OFDM symbol in WLAN is 4μs. Therefore, another limitation of schemes to improve signal power and range (e.g., link budget) is the defined OFDM symbol length of the system in which they operate.

[0066] In order to improve the link budget, a duplication (DUP) mode is proposed to maximize the bandwidth (BW) utilization to increase the transmission range and power of LPI WiFi. The DUP mode in frequency domain (DUP-F) replicates the DCM signal tones in the frequency domain by using twice the PPDU BW compared to the DCM signal defined in IEEE 802.11ax. In the proposed LPI EHT DUP-F mode, each OFDM symbol carries four copies of half of the data segment s(i), and the entire data segment requires two OFDM symbols. Therefore, for a given PPDU BW, the DUP-F mode requires two IFFT processes to generate two corresponding OFDM symbols to transmit the data segment s(i), while in IEEE 802.11ax DCM, only one IFFT (and one OFDM symbol) is required to transmit the same size data segment s(i). Similarly, the DUP-F mode receiver requires two FFT processes to detect the entire data segment s(i). The benefit of DUP-F mode compared to DCM with the same BW is that the SNR value of each data tone can be doubled to improve link performance and link budget.

[0067] Although DUP-F mode can enhance strength and range, it requires the source and destination stations to change frequency domain processing relative to the processing done in the context IEEE 802.11ax DCM transmission. Such a change may be undesirable. Therefore, a first exemplary embodiment enabling a time domain replication mode, hereinafter referred to as DUP-T mode, will now be described. As will now be described, in DUP-T mode, OFDM symbols are replicated one or more times in the time domain to increase the link budget.

[0068] in this regard, Figure 4 1 shows a logical block diagram of an OFDM symbol generator 400 according to an exemplary embodiment, which may be implemented by a processing unit 110 of a source station (eg, AP 102 or STA 104) to support a DUP-T mode. Figure 5 FIG. 4 shows OFDM symbols generated by generator 400 in the frequency domain and the time domain. Figure 4 In the example of , the generator 400 includes a low density parity check (LDPC) encoder 402, which receives an input source word u of information bits and outputs a corresponding codeword c. The source word u can be viewed as a 1×k row vector or a one-dimensional binary 1×k matrix u=[u1,...,u k]. The k-bit source u is encoded into a corresponding n-bit codeword by LDPC encoding 402 by multiplying the source word u with a generator matrix G (e.g., c=u·G). The n-bit codeword c includes k information bits (corresponding to the k bits of the source word u) and nk parity check bits. In an exemplary embodiment, a known process for generating LDPC codewords from source words using a generator matrix G can be applied to perform LDPC encoding 402. As is known in the art, the generator matrix G corresponds to a parity check matrix H, and each codeword c satisfies the formula: H·c=0.

[0069] The codeword c is then DCM modulated, and in an exemplary embodiment, the DCM modulation applies the same DCM modulation technique used for 802.11ax compatible DCM modulation. In this regard, the constellation mapper 404 is used to modulate the data segment s(i) representing a coded bit set from the codeword c to a first modulation symbol set (e.g., QPSK or N-quadrature amplitude modulation (N-QAM) or other constellation symbol scheme). In the case of DCM modulation, the constellation mapper 404 modulates the same bit information from the data segment s(i) onto two separate subcarriers so that each of the two subcarriers carries the same bit information. In some examples, a different constellation mapping may be used for each subcarrier. For example, the constellation mapping of one subcarrier may be phase rotated relative to another subcarrier. The first modulation symbol set is then mapped to a first frequency subcarrier set of the OFDM symbol, and the second modulation symbol set is mapped to a second frequency subcarrier set of the OFDM symbol using the LDPC tone mapping applied by the LDPC tone mapper 406.

[0070] Therefore, the LDPC tone mapper 406 output includes two data segments s(i): c1 and s(i) c2 DCM signal, each data segment occupies the corresponding frequency segment of the OFDM subcarrier, each data segment s(i) c1 and s(i) c2 Carrying the same bit information (for example, data segment s(i)). c1 and c2 ) performs an inverse fast Fourier transform (IFFT) operation 408 (in an exemplary embodiment, it can be implemented using an inverse discrete Fourier transform (IDFT)) to generate a data segment comprising data segment s c1 and c2In an exemplary embodiment, a time domain duplication (DUP-T) operation 410 is then applied to duplicate OFDM symbol q and apply a linear phase rotation θ to obtain a time-adjacent duplicate OFDM symbol q carrying the same bit information as OFDM symbol q. d The two OFDM symbols q and q d Forming a portion of a packet (eg, a portion of the LPI payload 204 of the PPDU 200 ) that is modulated onto a carrier frequency and transmitted over the wireless medium 106 to the destination station.

[0071] like Figure 5 As shown, two OFDM symbols q and q d Each includes a data segment s(i) c1 and s(i) c2 In the illustrated embodiment, the first frequency segment of the subcarriers corresponding to the lower half of the PPDU BW carries the data segment s c1 , the second frequency band of the subcarriers corresponding to the upper half of the PPDU BW carries the data segment s(i) c2 . Data segment s(i) c1 and s(i) c2 Each carries the same bit information from codeword c. Therefore, the receiving STA will transmit the same bit information in two OFDM symbols q and q d In the process of receiving four copies of the same bit of information. Therefore, Figure 4 and Figure 5 The DUP-T mode shown in uses DCM signals in two adjacent OFDM symbols to carry the same data segment s(i), while 802.11ax DCM uses only one OFDM symbol with the same PPDU BW. Figure 4 and Figure 5 The data rate of the DUP-T mode in 802.11ax is the same as the data rate of the proposed LPI EHT DUP-F mode described above. Under the same bandwidth, the data rate of the DUP-T mode is half the data rate of the 802.11ax DCM.

[0072] although Figure 4 and Figure 5 The embodiment of the DUP-T mode using DCM shown in FIG. 1 shows only a single repeated OFDM symbol, but in further exemplary embodiments, more than one linearly phase-shifted copy of the OFDM symbol q may be generated. This carries the DCM modulated signal (e.g., s ) in the frequency domain in the DUP-T mode using DCM. c1 and c2) is replicated one or more times. The kth replicated OFDM symbol in the time domain can be applied with a linear phase rotation θ k (θ k ∈[0,2π),k=1,2,…), which means that the subcarriers of OFDM symbols in the frequency domain are right cyclic shifted The position of , where M is the total number of subcarriers on the OFDM symbol.

[0073] exist Figure 4 and Figure 5 In the embodiment of the DUP-T mode using DCM shown in FIG. 4 , it will be appreciated that multiple OFDM symbols q and q are generated in the DUP-T operation 410 by replicating the samples in the first OFDM symbol q in the time domain with an appropriate linear phase rotation θ after IFFT. d Thus, in contrast to the LPI EHT DUP-F mode described above (which requires two IFFT operations 408), only a single IFFT operation 408 is required to encode the data segment s(i). Figure 4 and Figure 5 The embodiment of the DUP-T mode shown generates multiple OFDM symbols q T ,q d T The station may combine the corresponding replicated OFDM symbols before performing an FFT operation at the receiver. Therefore, in an exemplary embodiment, only a single FFT operation is required to detect each data segment s(i). When the receiver combines the received OFDM symbols q T and one or more corresponding replicated OFDM symbols q d(1) T To q d(k) T When , the linear phase rotation θ applied to each replicated OFDM symbol k Diversity can potentially be provided in the frequency domain.

[0074] In some exemplary embodiments, rather than with respect to data segment s(i) c1 Use data segment s(i) c2 Instead of phase-rotated constellation modulation, in some exemplary embodiments, the data segment s(i) is simply copied to two DCM subcarrier sets without any relative phase rotation or change in modulation scheme. For example, half of the PPDU BW is occupied by exactly the same duplicated information as the other half of the PPDU BW. This can be extended to repeating the other half of the PPDU BW to any PPDU BW frame, such as 80, 160 or 320 MHz.

[0075] In another exemplary embodiment, time-domain OFDM symbol replication may be performed without using DCM. Figure 6 and Figure 7 Another exemplary embodiment of a DUP-T mode without using DCM is shown. Figure 6 Shows something like Figure 4 An example of an OFDM symbol generator 450 of the OFDM symbol generator 400 is shown, except that the constellation mapper 404 and the LDPC tone mapper 406 of the OFDM symbol generator 450 do not apply DCM when modulating the codeword c bit information into the modulation symbol. Therefore, since the same bit information is not replicated in the frequency domain, the subcarrier set can be used to carry twice the amount of bit information compared to when DCM is used. For example, half of the subcarriers can be used to carry bit information corresponding to the first data segment s(i), and the other half of the subcarriers can be used to carry bit information corresponding to a different data segment s(j). Each OFDM symbol q carries bit information of two data segments s(i) and s(j).

[0076] Figure 6 and Figure 7 An example is shown in which the DUP-T operation 410 replicates OFDM symbol q three times with corresponding linear phase rotations θ1, θ2, and θ3. The first OFDM symbol q and its linear phase rotated repeated OFDM symbol q d1 ,q d2 ,q d3 Each carries the same data segments s(i) and s(j). It should be understood that data segments s(i) and s(j) can be considered as a single data segment, which is twice the size of the data segments used in the DCM system.

[0077] Therefore, with Figure 4 and Figure 5 Compared to the DUP-T mode using DCM (in which the PPDU BW of an OFDM symbol includes two copies of the same data segment), in the case of the OFDM symbol generator 450, the same PPDU BW can be used for twice the amount of bit information (e.g., data segments s(i) and s(j)).

[0078] The DUP-T without DCM produces the same data rate and SNR in the time domain samples as the DUP-T with DCM (e.g., four OFDM symbols can be used to send four copies of two data segments s(i) and s(j)). The implementation of the DUP-T without DCM can be simplified relative to the DUP-T with DCM because it reduces the IFFT operations and FFT operations in the source station and the destination station, respectively. For example, to send two data segments s(i) and s(j), only one IFFT is required in the DUP-T without DCM, while two IFFT operations are required in the DUP-T with DCM, and four IFFT operations are required in the LPI EHT DUP-F described above.

[0079] For a given PPDU BW, the DUP-T and DUP-F modes described above have the same maximum transmit power, which means that both modes have the same transmit range under the same channel conditions. In DUP-T, the link budget is improved by repeating OFDM symbols that convey the same data information, resulting in lower spectral efficiency and data rate compared to the case without OFDM replication in the time domain.

[0080] The simplest PPDU frame for DUP-T mode with or without DCM can be a 20MHz bandwidth PPDU. However, a 20MHz DUP-T mode without DCM (e.g. Figure 7 ) is the data rate Figure 5 The frequencies shown in use twice the 20 MHz DUP-T of the DCM (eg, each OFDM symbol can carry two different data segments instead of two copies of one data segment).

[0081] In another exemplary embodiment, the features of the LPIDUP-F mode and the DUP-T mode described above may be combined, referred to in the present disclosure as a DUP-F+DUP-T mode. Figure 8 An example of an OFDM symbol generator 460 is shown. In the symbol generator 460, the data segment s(i) is divided into a first half segment s(i) / 21 and a second half segment s(i) / 22. The constellation mapper 404 applies DCM to map the first half data segment s(i) / 21 to a first set of modulation subcarrier symbols and to map a phase-rotated copy s(i)' / 21 of the first half data segment to a second set of modulation subcarrier symbols. The first set of modulation symbols and the second set of modulation symbols correspond to a first set of subcarriers and a second set of subcarriers, respectively, which collectively correspond to half of the PPDU BW of the first OFDM symbol q1. The constellation mapper 404 applies DCM to map the second half data segment s(i) / 22 to the first set of modulation subcarrier symbols and to map the phase-rotated copy s(i)' / 22 of the second half data segment to a second set of modulation subcarrier symbols, which collectively correspond to half of the PPDU BW of another OFDM symbol q2.

[0082] In the frequency duplication operation DUP-F 462, the set of modulated subcarriers carrying the first half data segment s(i) / 21 and its DCM copy s(i)' / 21 are collectively duplicated, thereby obtaining a set of subcarriers corresponding to the PPDU BW of the first OFDM symbol q1, which includes four copies of the same bit information, namely, two copies of s(i)' / 21 and two copies of s(i) / 21. The set of subcarriers is mapped to the data carrier corresponding to the first OFDM symbol q1 using the LDPC tone mapping applied by the LDPC tone mapper 406. Similarly, another OFDM symbol q2 is generated, which includes four copies of the bit information of the second half data segment, namely, two copies of s(i)' / 22 and two copies of s(i) / 22.

[0083] The subcarriers corresponding to the two OFDM symbols q1 and q2 are respectively subjected to IFFT operations 408 to obtain OFDM symbol q1 (which carries four copies of the same bit information, corresponding to the first half of the data segment s(i)) and OFDM symbol q2 (which carries four copies of the same bit information, corresponding to the second half of the data segment s(i)). In an exemplary embodiment, a time domain replication (DUP-T) operation 410 is then applied to replicate OFDM symbol q1 and apply a linear phase rotation θ1 to obtain a temporally adjacent replicated OFDM symbol q 1d , and also replicates OFDM symbol q2 and applies a linear phase rotation θ1 to obtain a temporally adjacent replicated OFDM symbol q 2d .

[0084] In some applications, the DUP-F+DUP-T mode can further improve the link budget by reducing the data rate.

[0085] For illustration, Tables 1 and 2 show the minimum data rates for the different transmission options for the different transmission BWs described above.

[0086] Table 1: Data rates of DUP-T, DUP-F, and DUP-F+DUP-T using DCM

[0087]

[0088] Table 2 Data rate of DUP-T and data rate of DUP-F without using DCM

[0089]

[0090] As described above, in the DUP-T mode, the number of duplicated OFDM symbols may be more than one, which may provide a flexible trade-off between link budget and data rate.

[0091] When the PPDU BW is greater than 80MHz, the DUP-F mode preamble detection is limited to one 80MHz channel, assuming that STAs compliant with 802.11be will only be scheduled to stay on the 80MHz channel. In the case of the DUP-T mode using one copy of the OFDM symbol, the preamble detection can be achieved by combining the preamble sent over one 80MHz channel in two different OFDM symbols. Therefore, the DUP-T mode can achieve more robust preamble detection than the DUP-F mode.

[0092] In the exemplary embodiments described above, after LDPC encoding, the data segment s(i) is replicated in the frequency domain or the time domain. In alternative exemplary embodiments, the same information bits corresponding to the source word u are LDPC encoded multiple times and then included in the same PPDU. In these embodiments, multiple LDPC encodings can be performed in a manner similar to that performed in a hybrid automatic repeat request (HARQ) retransmission context, except that the differently encoded data is included in the same PPDU instead of in a retransmission PPDU.

[0093] To provide context and introduce a set of permuted extension (PE) LDPC code families, the description of different LDPC codes will be described in the context of incremental redundancy hybrid automatic repeat request (IR-HARQ) not limited to LPI applications. Communication between STAs in the network 100, including, for example, communication between STA 104 and AP 102, is achieved by encoding source words using LDPC coding techniques to generate codewords. The codewords obtained by LDPC encoding the corresponding source words are embedded in packets or frames (e.g., PPDUs) modulated and transmitted between AP 102 and STA 104 over the wireless medium 106.

[0094] The encoding may be performed at the AP 102 to generate network centric warfare (NCW) codewords c1 to c NCW to be included in PPDU 300. Fig. 10AAn example of an encoding process 500 is shown. In an exemplary embodiment, the encoding process 500 may be the same as a known process for generating LDPC code words for a PPDU compliant with IEEE std 802.11 REVmdD4.0. In this regard, data bits (e.g., bits constituting a PPDU payload) are scrambled, shortened, and segmented 502 to obtain information blocks IB1 to IB NCW Each information block is k bits long. Information blocks IB1 to IB NCW are used as respective k-bit source words u1 to u2 for respective LDPC encoding operations 504. Ncw , and obtain the corresponding n-bit code words c1 to c NCW In some embodiments, the codewords may be punctured and repeated 506 accordingly. In the description of IR-HARQ, the subscript "j" is used to denote a general information block IB. j 、Source word j and codeword c j , where 1≤j≤NCW.

[0095] In an exemplary embodiment, the LDPC encoding applied in the exemplary embodiment uses LDPC codes specified in one or more of the IEEE 802.11 protocols, including the code rate, codeword block size, and parity check matrix specified in, for example, IEEE std 802.11 REVmdD4.0.

[0096] IEEE std 802.11REVmdD4.0 specifies the coding parameters of many LDPC codes. A unique parity check matrix (PCM) H is defined for each specific combination of code rate R and LDPC codeword length N. More specifically, a basic PCM Hb is defined for each combination of code rate R and LDPC codeword length N. The corresponding PCM H is obtained by lifting the basic PCM Hb by a lifting factor Z, so that each matrix element in the basic PCM Hb is replaced by a corresponding cyclic submatrix Pi of size Z×Z. These cyclic submatrices are cyclic permutations of the Z×Z unit matrix, or Z×Z empty matrices. Each submatrix element in the basic PCM Hb is filled with a value w (0≤w≤Z) specifying the corresponding cyclic submatrix Pw, or with an empty indicator indicating an empty matrix. The value "w" indicates the number of cyclic right shifts applied to the Z×Z unit matrix to reach the submatrix Pw.

[0097] To illustrate, Fig. 10BA basic PCM Hb (4×24) of a rate 5 / 6 LDPC code is shown, where n=1944 and Z=81. The basic PCM Hb can generate a PCM H of size (4*81) rows×(24*81) columns. Each array element in the basic PCM Hb indicates the number of cyclic right shifts w applied to the 81×81 identity matrix (e.g., element (0,0) specifies 13 cyclic right shifts), or an empty matrix (e.g., element (0,12) specifies “-”, indicating an 81×81 zero matrix). The basic PCM Hb includes two parts, namely, an information part H of size ((nb-kb)×kb) bI and a parity check part H of size ((nb-kb)×(nb-kb)) bP , where kb = k / Z, nb = n / Z. As mentioned above, k is the size of the source word u, and n is the size of the codeword c.

[0098] Fig. 10B Also shown is the identity matrix P0 for the simplified case of Z=4, as well as its first circular right-shifted version (P1) and third circular version (P3), showing examples of w=0, 1 and 3 when Z=4, respectively.

[0099] Codewords c1 to c NCW Each codeword can be punctured and repeated accordingly and combined into a code stream to be included in the PPDU. NCW is modulated onto an RF signal and sent to the destination STA 104.

[0100] The destination STA 104 is used to receive the signal modulated by the PPDU sent by the source AP 102, and convert the received codeword c1 T Decoded into c embedded in PPDU 300 NCW T (The superscript "T" indicates that the codeword is received at the destination STA 104 after passing through the channel of the wireless medium 106.) In an exemplary embodiment, the received signal is equalized to reduce inter-symbol interference caused by the RF channel and demodulated to generate the codeword c1 T to c NCW T The decoder converts the LDPC codeword c1 into an initial set of soft channel bit values ​​for each codeword in T Decode to c NCW T As is known in the art, decoding is performed based on a parity check matrix (PCM) H and a Tanner graph corresponding to a generator matrix G applied at a transmission source to generate LPDC codewords c1 to c NCWIn this regard, the decoding uses a log-likelihood ratio (LLR) calculator, which is used to calculate the codeword c q T The LLR values ​​of each soft channel bit are initially assigned to the corresponding variable nodes of the Tanner graph during decoding. The LDPC decoder then applies an iterative message passing algorithm (MPA) based on the log-likelihood ratio (LLR) values ​​to successfully decode the codeword c q T And restore the source word s j , or determine the codeword c q T As is known in the art, if the decoded codeword c q T Can satisfy H·b j T =0, then the received codeword c q T In an exemplary embodiment, a codeword c1 in the received PPDU is determined to be valid (eg, successfully decoded). T to c NCW T Provides decoding status. Specifically, each codeword c1 T to c NCW T The decoding status of can be: (a) decoding success or (b) decoding failure.

[0101] The destination STA 104 is configured to generate a feedback message and send it to the source AP 102. The source AP 102 is configured to identify the codeword (if any) that failed to be decoded at the destination STA 104 according to the CW bitmap included in the feedback message, and then retransmit information about the codeword (or a version of an erroneous codeword) that failed to be decoded in a new PPDU 300.

[0102] In at least some exemplary embodiments, the retransmission process performed by the source AP 102 to retransmit the codeword for which decoding failed and the subsequent decoding process performed at the destination STA 104 are used to increase the chance of success based on the information known from the failed transmission. In exemplary embodiments, the retransmission process performed by the source AP 102 to retransmit the codeword for which decoding failed relies on IR-HARQ. Specifically, an IR-HARQ code built on the existing LPDC code is proposed, thereby achieving backward compatibility.

[0103] Now refer to Fig.11 , about the failed codeword c T qDescribe the retransmission process performed by AP 102. Failed codeword c T q Corresponds to the source word s q In the initial transmission, the LDPC coded source word s q The information block IB obtained by the scrambling and segmentation operation of set f j As described below, for each successive retransmission, AP 102 is operable to perform encoding process 802(i) (where 1≤i≤R max , R max represents the maximum number of retransmissions). The encoding process 802(i) includes a permutation operation 804 and an LDPC encoding operation 504. T q Information Block IB q Perform a substitution operation 804 to generate a substitution source word s q(i) , the replacement source word s q(i) The original source word q(i) The interleaving is done according to the defined permutation mapping π. The source word s is permuted according to the generator matrix G of the LDPC coding operation q(i) LDPC encoding is performed to generate the corresponding permuted extended codeword c'q(i). Each encoding process 802(i) (1≤i≤R max ) The retransmission corresponds to the LDPC codeword c added to the initial transmission q(0) is a further extension of , so i also represents the number of times the LDPC code has been extended.

[0104] exist Fig.11 , the encoding process 802(0) corresponds to the encoding of the original length k information block IB during the initial transmission (i=0). q (ie, the source word s q ) performs LDPC encoding operation 504 to generate a length n codeword s q The encoding processes 802(1) and 802(i) correspond to the information block IB. q The encoding operation is performed to generate a first extended codeword c for the first IR-HARQ transmission and the i-th IR-HARQ transmission, respectively. q(1) and the i-th extended codeword c q(i) .

[0105] like Fig.11 As shown, the encoding process 802(0) converts the source word s into q (corresponding to information block IB q ) is multiplied with the initial transmission to perform LDPC encoding. The generator matrix G corresponds to the original transmission PCM matrix H (hereinafter referred to as PCM matrix H(0)), which is obtained by lifting the basic PCM matrix H as described above. b(hereinafter referred to as the basic PCM matrix H b (0))Export.

[0106] Each extended coding process 802(i) (i>0) is used to generate a corresponding codeword c q(i) , the code word c q(i) The output of the corresponding generator matrix G(i) corresponds to the corresponding PCM matrix H(i), which is the i-th extension of the original transmission PCM matrix H(0). In the exemplary embodiment, the same encoding operation 504 (i.e., the same generator matrix G) is applied in each extension encoding process 802(i). Therefore, the permutation operation 804 is used to rearrange the original information block IB. q The information bits included in the substitution source word s p ' (i) , the replacement source word s p ' (i) When multiplied by the generator matrix G, the extended codeword c is obtained q(i) , the extended codeword c q(i) Equivalent to the original source word s q (ie, IBq) is multiplied by a corresponding generator matrix G(i) corresponding to a corresponding PCM matrix H(i) which is the i-th extension of the original transmission PCM matrix H(0).

[0107] In an exemplary embodiment, the PCM matrix H(i) corresponds to a predefined permutation mapping π(i). Specifically, for each basic LDPC code that can be used for initial transmission, a set of permutation mappings π(i) (1≤i≤R max As mentioned above, IEEE std 802.11 REVmd D4.0 specifies a unique basic PCM H for each specific combination of code rate R and LDPC codeword length N. b (hereinafter referred to as basic PCM H b (0)). In an exemplary embodiment, for each basic PCM H b Define R max The permutation mapping set {π(1)...π(R max )}, thus defining the corresponding R max Extended Basic PCM Family {H b (1) to H b ( Rmax )}.

[0108] exist Fig.11 In the LDPC codeword c q(o) Corresponding to the mother LDPC code generated based on PCM H(0), the LDPC codeword {c q(i) ……c q(Rmax)} corresponds to the PCM-based {Hb (1) to H b ( Rmax )} generates the corresponding extended LDPC code, each of which is derived from PCM H b (0) Derived. In an exemplary embodiment, the permutation map is stored in a memory of the AP 102.

[0109] Fig.12 A table is shown that defines R max = 15 permutation mapping set {π(1) ... π(15)}, applicable to the basic PCM H defined in Table f-3(d) of 802.11REVmd4.0 b (number of information columns k / Z = 20) for a rate 5 / 6 LDPC code, where n = 1944, k = 1620, Z = 81. Each row (indexed from i = 1 to 15) corresponds to a corresponding permutation π(1) ... π(15). Fig.13 shows the original PCM H b (0) (e.g., as specified in IEEE std 802.11REVmdD4.0 and in Fig. 10B ) and the i=1 extended PCM H defined by the permutation map π(1) b As described above, the basic PCM Hb(0) includes two parts, namely, the information bit part Hb(1) of size ((nb-kb)×kb) bI (0) and the parity bit part H of size ((nb-kb)×(nb-kb)) bP , where kb = k / Z and nb = n / Z. Fig.13 As shown, the basic PCM Hb(1) consists of three parts, namely, the information bit part H with a nominal size of ((nb-kb)×kb) bI (1), empty part (with the original PCMH b (0) The parity bit part H bP (0)), and the parity bit part H of size ((nb-kb)×(nb-kb)) bP The information bit part H of the basic PCM Hb(1) bI (1) is achieved by applying the permutation function to the original basic information part H bI (0) to select from raw PCM PCM H b (0) obtains a subset of the permutation columns, as defined by the permutation mapping π(1). The parity bit portion H of PCM Hb(1) bP The parity bit part H of the original PCM Hb(0) is bPThe right shift is generated by (nb-kb) columns, resulting in an expansion of the matrix and a set of (nb-kb) empty columns.

[0110] Fig.13 The tables shown in can be collectively represented as:

[0111]

[0112] Among them, the matrix H b The first (nb-kb) rows represent the original PCM H b (0), matrix H b The second (nb-kb) row represents the first extended PCM H b (1).

[0113] refer to Fig.12 "fi" means that the original basic information part H bI The corresponding column j (0≤j≤(kb-1)) in (0) is mapped to the i-th extended information part H bI The set of column indices for column j in (i). Therefore, Fig.12 Each row in H is mapped to the original basic information part H by providing in the column position corresponding to the permutation code bI (0) The corresponding column number specifies the permutation mapping Π i Therefore, in the case of the column index set "f1" defined by the permutation and shortening mapping PM(1), the first extended information part H bI (1) Reduced to:

[0114] f1={f1(j)}={f1(7),f1(5),f1(3),f1(8),f1(6),f1(4),f1(9),f1(1),f1(2),f1(0),f1(13)

[0115] f1(19),f1(11),f1(18),f1(14),f1(12),f1(17),f1(16),f1(15),f1(10)}where: H bI (0) Column j=7 is mapped to H bI (1) Column j = 0

[0116] H bI (0) Column j=1 is mapped to H bI (1) Column j = 7

[0117] And so on.

[0118] As described above, in the exemplary embodiment, the original generator matrix G is applied at the LDPC encoding operation 504 in each extended encoding process 802 (i) (i>0), so the source word s must be manipulated through the permutation operation 804 q , so that the extended encoding process 802(i) can output the equivalent of an LDPC encoding operation applying a unique generator matrix corresponding to the extended PCM H(i).

[0119] In this regard, the permutation operation 804 of the extended coding process 802(i) (i>0) is used to define the information bit portion H of the basic PCM Hb(i). bI The permutation and shortening mapping π(i) of (i) rearranges the source word s q The information bits in , to generate the permutation source word S q p (i) In an exemplary embodiment, for each basic PCM H b Definition of R max The permutation mapping set {π(1)...π(R max )} defines a corresponding permutation set, which can be respectively composed of LDPC encoding processes 802(1) to 802(R max )'s permutation operation 804 is applied.

[0120] Reference again Fig.12 and an exemplary permutation map π(1). In an exemplary embodiment, the index value in the table row corresponding to the permutation map π(1) maps to the original source word S q The corresponding set of Z bits in the permutation source word S and the position of the index value in the table row indicate where these Z bits should be located q p (i) The position in.

[0121] In various applications and embodiments, the retransmission codeword c included in the retransmission PPDU 300R q(i) As described above, the destination STA 104 is used to store any codeword c that failed to be decoded and is therefore marked as a decoding failure. j T The LPDC coding scheme is systematic so that the destination STA 104 can combine the information from the original codeword transmission with the extended information received in the subsequent retransmission.

[0122] IEEE std 802.11REVmdD4.0 specifies a unique basic PCM Hb (hereinafter referred to as basic PCM Hb(0)) for each specific combination of code rate R and LDPC codeword length N. In an exemplary embodiment, R max The permutation mapping set {π(1)...π(Rmax )} is defined for each of a plurality of basic PCM Hb.

[0123] In this regard, the following table indicates the permuted extended LDPC code families generated for the different LDPC codes specified in IEEE 802.11 REVmdD4.0. Fig.12 The permutation mapping information is shown in the same manner as described. Each table shows the information column index fi = {fi(j)} of the basic PCM for each permutation operation. Combining fi = {fi(j)} shown in the table with the corresponding basic PCM of the LDPC code defined in IEEE 802.11REVmdD4.0 can provide the basic PCM of the corresponding permutation extended (PE) LDPC retransmission code.

[0124] Table 2A below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1944, Z=81, and a code rate of 1 / 2. Combining fi={fi(j)} shown in Table 2A below with the basic PCM with a code block length of n=1944, k=972, Z=81, and a code rate of 1 / 2 defined in [802.11 REVmdD4.0 Table F-3(a)] can generate the basic PCM of the PE LDPC code. The number of information columns of the basic PCM is k / Z=12. The LDPC code family is obtained by adding 972 (i.e., 12*81) additional parity check bits in each generated extension.

[0125] Table 2A Information column index fi = {fi(j)} of the i-th extended PE code basic PCM of 802.11 LDPC code (n = 1944, rate 1 / 2):

[0126]

[0127] Table 2B below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1944, Z=81, and a code rate of 2 / 3. Combining f_i={f_i(j)} shown in Table 2B below with a basic PCM with a code block length of n=1944, k=1296, Z=81, and a code rate of 2 / 3 (as defined in [Table F-3(b), 802.11REVmdD4.0]) can generate a basic PCM for a PE LDPC code. The number of information columns of the basic PCM is k / Z=16. The LDPC code family is obtained by adding 648 (i.e., 8×81) additional parity check bits in each generated extension.

[0128] Table 2B: Information column index fi={fi(j)} of the basic PCM of the i-th extended PE code of 802.11 LDPC code (n=1944, rate 2 / 3):

[0129]

[0130] Table 2C below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1944, Z=81, and a code rate of 3 / 4. Combining fi={fi(j)} shown in Table 2C below with the basic PCM matrix defined in [Table F-3(c), 802.11REVmdD4.0] with a code block length of n=1944, k=1458, Z=81, and a code rate of 3 / 4 can generate the basic PCM of the PE LDPC code. The number of information columns of the basic PCM is k / Z=18. The LDPC code family is obtained by adding 486 (i.e., 6×81) additional parity check bits in each generated extension.

[0131] Table 2C: Information column index of basic PCM of PES code of 802.11 LDPC code (n=1944, rate 3 / 4) ith extension f_i={f_i(j)}:

[0132]

[0133] Table 2D below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1944, Z=81, and a code rate of 5 / 6. Combining fi={fi(j)} shown in Table 2D below with the basic PCM matrix of code block length n=1944, k=1620, Z=81, and a code rate of 5 / 6 defined in Table F-3(d) of 802.11 REVmdD4.0 can generate the basic PCM of the PE LDPC code. The number of information columns of the basic PCM is k / Z=20. The LDPC code family is obtained by adding 324 (i.e., 4×81) additional parity check bits generated by each extension.

[0134] Table 2D: Information column index of basic PCM of PES code of 802.11 LDPC code (n=1944, rate 5 / 6) ith extended PES code f_i={f_i(j)}:

[0135]

[0136]

[0137] Table 3A below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1296, Z=54, and a code rate of 1 / 2. The 802.11 LDPC code with a code block length of n=1296, k=648, Z=54, and a code rate of 1 / 2 is defined in [Table F-2(a), 802.11 REVmdD4.0]. The number of information columns of the basic PCM is k / Z=12. The LDPC code family is obtained by adding 648 (i.e., 12×54) additional parity check bits in each generated extension.

[0138] Table 3A shows the information column index f of the basic PCM for each permutation operation i ={f i (j)}. The f shown in Table 3A i ={f i (j)} Combined with Table F-2(a) in 802.11REVmdD4.0, PCM of PE LDPC code can be generated.

[0139] Table 3A Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=1296, rate 1 / 2) i ={f i (j)}:

[0140]

[0141] Table 3B below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1296, Z=54, and a code rate of 2 / 3. The 802.11 LDPC code with a code block length of n=1296, k=864, Z=54, and a code rate of 2 / 3 is defined in [Table F-2(b), 802.11 REVmdD4.0]. The number of information columns of the basic PCM is k / Z=16. The LDPC code family is obtained by adding 432 (i.e., 8×54) additional parity check bits in each generated extension.

[0142] Table 3B shows the information column index f of the basic PCM for each permutation operation i ={f i (j)}. The following table 3B shows f i ={f i (j)} Combined with Table F-2(b) in 802.11REVmdD4.0, the basic PCM of PE LDPC code can be generated.

[0143] Table 3B Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=1296, rate 2 / 3) i ={fi (j)}:

[0144]

[0145]

[0146] Table 3C below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1296, Z=54, and a code rate of 3 / 4. The 802.11 LDPC code with a code block length of n=1296, k=972, Z=54, and a code rate of 3 / 4 is defined in [Table F-2(c), 802.11REVmdD4.0]. The number of information columns of the basic PCM is k / Z=18. The LDPC code family is obtained by adding 324 (i.e., 6×54) additional parity check bits in each generated extension.

[0147] Table 3C shows the information column index f of the basic PCM for each permutation operation i ={f i (j)}. The following table 3C shows f i ={f i (j)} Combined with Table F-2(c) in 802.11REVmdD4.0, the basic PCM of PE LDPC code can be generated.

[0148] Table 3C Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=1296, rate 3 / 4) i ={f i (j)}:

[0149]

[0150] Table 3D below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 1296, Z=54, and a code rate of 5 / 6. The 802.11 LDPC code with a code block length of n=1296, k=1080, Z=54, and a code rate of 5 / 6 is defined in [Table F-2(d), 802.11REVmdD4.0]. The number of information columns of the basic PCM is k / Z=20. The LDPC code family is obtained by adding 216 (i.e., 4×54) additional parity check bits generated by each extension. Table 3D shows the information column index f of the basic PCM for each permutation operation. i ={f i (j)}. The f shown in Table 3D below i ={f i(j)} Combined with Table F-2(d) in 802.11REVmdD4.0, the basic PCM of PE LDPC code can be generated.

[0151] Table 3D Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=1296, rate 5 / 6) i ={f i (j)}:

[0152]

[0153] Table 4A below corresponds to an extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 648, Z=27 and a code rate of 1 / 2. The 802.11 LDPC code with a code block length of n=648, k=324, Z=27 and a code rate of 1 / 2 is defined in [Table F-1(a), 802.11 REVmdD4.0]. The number of information columns of the basic PCM is k / Z=12. The LDPC code family is obtained by adding 324 (i.e., 12×27) additional parity check bits in each generated extension. Table 4A shows the information column index f of the basic PCM for each permutation operation. i ={f i (j)}. The following table 4A shows f i ={f i (j)} Combined with Table F-1(a) in 802.11REVmdD4.0, PCM of PE LDPC code can be generated.

[0154] Table 4A Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=648, rate 1 / 2) i ={f i (j)}:

[0155]

[0156]

[0157] The following Table 4B corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 648, Z=27, and a code rate of 2 / 3. The 802.11 LDPC code with a code block length of n=648, k=432, Z=27, and a code rate of 2 / 3 is defined in [Table F-1(b), 802.11 REVmdD4.0]. The number of information columns of the basic PCM is k / Z=16. The LDPC code family is obtained by adding 216 (i.e., 8×27) additional parity check bits in each generated extension. Table 4B shows the information column index f of the basic PCM for each permutation operation. i={f i (j)}. The following table 4B shows f i ={f i (j)} Combined with Table F-1(b) in 802.11REVmdD4.0, PCM of PE LDPC code can be generated.

[0158] Table 4B Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=648, rate 2 / 3) i ={f i (j)}:

[0159]

[0160] The following Table 4C corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 648, Z=27, and a code rate of 3 / 4. The 802.11 LDPC code with a code block length of n=648, k=486, Z=27, and a code rate of 3 / 4 is defined in [Table F-1(c), 802.11REVmdD4.0]. The number of information columns of the basic PCM is k / Z=18. The LDPC code family is obtained by adding 162 (i.e., 6×27) additional parity check bits in each generated extension. Table 4C shows the information column index f of the basic PCM for each permutation operation. i ={f i (j)}. The f shown in Table 4C i ={f i (j)} Combined with Table F-1(c) in 802.11REVmdD4.0, PCM of PE LDPC code can be generated.

[0161] Table 4C Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=648, rate 3 / 4) i ={f i (j)}:

[0162]

[0163]

[0164] Table 4D below corresponds to a permuted extended LDPC code family generated based on an 802.11 LDPC code with a code block length of 648, Z=27, and a code rate of 5 / 6. The 802.11 LDPC code with a code block length of n=648, k=540, Z=27, and a code rate of 5 / 6 is defined in [Table F-1(d), 802.11REVmdD4.0]. The number of information columns of the basic PCM is k / Z=20. The LDPC code family is obtained by adding 108 (i.e., 4×27) additional parity check bits in each generated extension. Table 4D shows the information column index f of the basic PCM for each permutation operation. i ={f i (j)}. The f shown in Table 4D i ={f i (j)} Combined with Table F-1(d) in 802.11REVmdD4.0, PCM of PE LDPC code can be generated.

[0165] Table 4D Basic PCM information column index f of the ith extended PE code of 802.11 LDPC code (n=648, rate 5 / 6) i ={f i (j)}:

[0166]

[0167] Refer again to the above Figures 3 to 9 The disclosed LPI range and power extension technology, in an exemplary embodiment, the PE-LDPC code family is used in conjunction with the replicated data segments in the same PPDU. The above-mentioned LPIDUP-F mode replicates the DCM signal in the frequency domain. Therefore, both the lower and upper half PPDU BWs send the same signal corresponding to the same coded bits.

[0168] According to an exemplary embodiment, a modified DUP-F mode with a PE-LDPC code will now be disclosed, wherein the lower half PPDU BW and the upper half PPDU BW carry the same data information but are sent using different signals corresponding to corresponding encoded code streams. The different encoded code streams belong to a first LDPC code and a permutation extension of the first LDPC code, respectively.

[0169] Fig.14A block diagram of an OFDM signal generator 700 is shown for enabling DUP-F mode with PE-LDPC codes. DUP-F mode with PE-LDPC codes requires a separate encoding process for each repeated copy of a data stream, i.e., one for the original LDPC code and one for each additional data stream, wherein each additional encoding process applies a corresponding PE-LDPC code in a manner similar to how a corresponding PE-LDPC code is used for consecutive retransmissions of the same data in a HARQ system.

[0170] To keep it simple, Fig.14 The OFDM signal generator 700 in FIG. 7 shows only two encoding processes 706 and 708, which respectively apply the original or first LDPC code and the second LDPC code (PE-LDPC code) as a permutation extension of the first LDPC code. However, an additional PE-LDPC encoding process may be included to provide an improved link budget at the expense of data rate.

[0171] In an exemplary embodiment, the PE-LDPC encoding process 708 can be based on the basic PCM application used for the first LDPC encoding process 706. The permutation mapping mode described above with respect to Tables 2A to 4D. In the first LDPC encoding process 706, the original source word u is provided to the corresponding LDPC encoding operation 402. The LDPC encoding operation 402 applies the generator matrix G to the original source word u to generate the first codeword c0. In the second LDPC encoding process 708 (i.e., the PE-LDPC encoding process), the original source word u is first subjected to a permutation operation 702, wherein its bits are interleaved according to the permutation mapping π. Then, the resulting permuted source word u is p is provided to a corresponding LDPC encoding operation 402, which in turn applies the same generator matrix G to the permuted source word u p , to generate the second codeword c1. The same LDPC encoding operation 402 (ie, the same generator matrix G) is applied to the original source word u and the permuted source word u p The first codeword c0 and the second codeword c1 will each include the same information bits, but in a different order, and will each include different parity check bits. It should be noted that for a system LDPC code such as an existing Wi-Fi LDPC code, after LDPC encoding 402, the information bit portion of the PE-LDPC codeword (codeword c1) can be replaced with information bits in the same order as the original source word u, or an interleaved version of the information bits (e.g., u p ) can be retained in codeword c1.

[0172] Each of the corresponding code words c0 and c1 is the same as the above Figure 8DCM constellation mapping is performed in a similar manner as described. For this description, the data segment s in the context of the OFDM signal generator 700 is considered to be the same size as the data segment of the above-described embodiment. In this regard, in the LDPC encoding process 706, the data segment s0(i) from the codeword c0 is divided into a first half segment s0(i) / 21 and a second half segment s0(i) / 22. The constellation mapper 404 applies DCM to map the first half data segment s0(i) / 21 to a first set of subcarriers, and maps a phase-rotated copy s0(i)' / 21 of the first half data segment to a second set of subcarriers that collectively corresponds to half of the PPDU BW of the first OFDM symbol q1. The constellation mapper 404 applies DCM to map the second half data segment s0(i) / 22 to the first set of subcarriers, and maps a phase-rotated copy s0(i)' / 22 of the second half data segment to a second set of subcarriers that collectively corresponds to half of the PPDU BW of the second OFDM symbol q2.

[0173] Similarly, in the LDPC encoding process 706, the data segment s1(i) from the codeword c1 is divided into a first half segment s1(i) / 21 and a second half segment s1(i) / 22. The constellation mapper 404 applies DCM to map the first half data segment s1(i) / 21 to a first set of subcarriers and to map a phase-rotated copy s1(i)' / 21 of the first half data segment to a second set of subcarriers that collectively corresponds to the other half of the PPDU BW of the first OFDM symbol q1. The constellation mapper 404 applies DCM to map the second half data segment s1(i) / 22 to the first set of subcarriers and to map a phase-rotated copy s1(i)' / 22 of the second half data segment to a second set of subcarriers that collectively corresponds to the other half of the PPDU BW of the second OFDM symbol q2.

[0174] At the LDPC tone mapper 406, the first half data segments s0(i) / 21 and s0(i)' / 21 corresponding to the first LDPC encoded codeword c0, and the first half data segments s1(i) / 21 and s1(i)' / 21 corresponding to the PE-LDPC encoded codeword c1 are collectively mapped to a corresponding set of OFDM subcarriers corresponding to the first OFDM symbol q1, and then provided to the IFFT operation 408 to generate the OFDM symbol q1.

[0175] The second half data segments s0(i) / 22 and s0(i)' / 22 corresponding to the first LDPC encoded codeword c0, and the second half data segments s1(i) / 22 and s1(i)' / 22 corresponding to the PE-LDPC encoded codeword c1 are collectively mapped to corresponding OFDM subcarrier sets corresponding to the second OFDM symbol q2, and then provided to the IFFT operation 408 to generate OFDM symbol q2.

[0176] In the illustrated embodiment, Fig.15 As shown, in OFDM symbol q1, the first half data segment s0(i) / 21 occupies the subcarriers associated with the first quarter of the PPDU BW, the first half data segment s1(i) / 21 occupies the subcarriers associated with the second quarter of the PPDU BW, the phase-rotated first half data segment s0(i)' / 21 occupies the subcarriers associated with the third quarter of the PPDU BW, and the first half phase-rotated data segment s1(i)' / 21 occupies the subcarriers associated with the fourth quarter of the PPDU BW. Therefore, the data segments from the first LDPC code and the PE-LDPC code alternate with each other in the frequency domain within the OFDM symbol, thereby providing additional frequency diversity.

[0177] At the destination station, the log-likelihood ratio (LLR) values ​​of the information bits in the original LDPC coded stream and the PE-LDPC coded stream transmitted through the lower and upper PPDU BWs may be combined, and layered LDPC decoding may be performed by using an LDPC decoder for the original LDPC code, wherein the LLRs of the information bits are additionally deinterleaved based on the received parity bits generated by the PE-LDPC encoding in the LDPC decoding.

[0178] According to an exemplary embodiment, the use of incremental PE-LDPC coding can also be applied to alternative DUP-T mode implementations. In the DUP-T mode described above, OFDM symbols are replicated in the time domain. In the case of a single copy of an OFDM symbol, the transmitted PPDU payload will include the original OFDM symbol and then its copy, both of which send the same signal corresponding to the same coded bits. Therefore, the PPDU payload will include a series of alternating and original and replicated OFDM symbols.

[0179] An exemplary embodiment of a DUP-T mode with a PE-LDPC code will now be described, wherein a first OFDM symbol and a subsequent second OFDM symbol carry the same data information but are sent using different signals corresponding to the corresponding encoded code streams. The differently encoded code streams can be implemented using the original LDPC code and a permutation extension of the original LDPC code, as described above with respect to IR-HARQ retransmissions. Fig.16 FIG. 7 is a logic block diagram of an OFDM signal generator 750 for implementing DUP-T with a PE-LDPC code. Fig.14 and Fig.15Similar to the described DUP-F mode embodiment with PE-LDPC code, the DUP-T mode with PE-LDPC OFDM symbol generator 750 also requires two LDPC encoding processes 756, 758. The first LDPC encoding process 756 applies a first LDPC code corresponding to the original or first LDPC code to the source word u. The second LDPC encoding process 758 applies a second LDPC code corresponding to the PE-LDPC code, which is a permutation extension of the original LDPC code, to the source word u.

[0180] like Fig.16 As shown, the first LDPC encoding process 756 includes an LDPC encoding operation 402, which applies the generator matrix G to the original source word u to generate the first codeword c0. In the second LDPC encoding process 758 (i.e., the PE-LDPC encoding process), the original source word u is first subjected to a permutation operation 702, wherein its bits are interleaved according to a permutation mapping π. Then, the resulting permuted source word u is p is provided to a corresponding LDPC encoding operation 402, which in turn applies the same generator matrix G to the permuted source word u p , to generate the second codeword c1. The same LDPC encoding operation 402 (ie, the same generator matrix G) is applied to the original source word u and the permuted source word u p The first codeword c0 and the second codeword c1 will each include the same information bits, but in a different order, and will each include different parity bits.

[0181] Each of the corresponding code words c0 and c1 is the same as the above Figure 4 The constellation mapper 404 of the first LDPC encoding process 756 applies DCM to map the data segment s0(i) from the codeword c0 to a first set of subcarriers and to map the phase-rotated copies s0(i)' of the data segment to a second set of subcarriers that collectively correspond to the PPDU BW.

[0182] Similarly, in the LDPC encoding process 758, data segment s1(i) from codeword c1 is provided to the constellation mapper 404, which applies DCM to map the data segment s1(i) to a first set of subcarriers and maps a phase-rotated copy s1(i)' of the data segment to a second set of subcarriers that collectively correspond to the PPDU BW.

[0183] At the LDPC tone mapper 406 of the first LDPC encoding process 756, data segments s0(i) and s0(i)' corresponding to the first LDPC encoded codeword c0 are mapped to OFDM subcarriers corresponding to the first OFDM symbol q0 and then provided to the IFFT operation 408 to generate OFDM symbol q0.

[0184] At the LDPC tone mapper 406 of the second LDPC encoding process 758, data segments s1(i) and s1(i)' corresponding to the PE-LDPC encoded codeword c1 are mapped to OFDM subcarriers corresponding to the second OFDM symbol q1 and then provided to the IFFT operation 408 to generate OFDM symbol q1.

[0185] As indicated at block 760, the OFDM generator 750 is operable to alternately output OFDM symbols from the first LDPC encoding process 756 and the second LDPC encoding process 758 to provide a serial sequence of OFDM symbols q0, q1, etc. for the payload of the PPDU.

[0186] At the destination station, the original LDPC coded stream can be combined with the two adjacent OFDM symbols q0 T ,q1 T The log-likelihood ratio (LLR) values ​​of the information bits in the transmitted PE-LDPC coded stream, when related to the received parity bits generated by the PE-LDPC coding in the LDPC coding, can be used to perform layered LDPC decoding by using an LDPC decoder of the original LDPC code, wherein the LLRs of the information bits are additionally deinterleaved.

[0187] Above about Figure 3 The depicted PPDU 200 is an example of a possible PPDU frame format. Reliable auto-detection of the PPDU preamble portion is an important aspect of LPI transmission. Further exemplary embodiments are directed to a frame preamble structure that can improve auto-detection performance in an LPI environment. Fig.18 The frame format of an EHT LPI PPDU 900 according to another exemplary embodiment is shown, which can be used for wide BW LPI LR communication. As shown, the PPDU 900 includes a preamble 901 and a payload portion 404. The preamble 901 includes a legacy preamble (L-Preamble) field 206, which, as described above, is used for backward compatibility and coexistence with legacy IEEE 802.11 devices.

[0188] The EHT portion of the preamble 901 includes fields for the following: U-SIG 1, U-SIG 2, RU-SIG 1, RU-SIG 2, EHT-STF 216, and EHT-LTF 218. In some embodiments, the signals included in the preamble portion 901, excluding the EHT-STF 216 and the EHT-LTF 218, are repeated in the frequency domain, for example, every 20 MHz.

[0189] In an exemplary embodiment, U-SIG 1 and U-SIG 2 each encode different information. The information may be of the type described above with respect to U-SIG 212 of PPDU 200. RU-SIG-1 carries the same information as U-SIG 1, and RU-SIG-2 carries the same information as U-SIG 2. U-SIG 1, U-SIG 2, RU-SIG 1, and RU-SIG 2 are each sent using different corresponding OFDM symbols, and each may be replicated in the frequency domain within its corresponding OFDM symbol. For example, in Fig.18 In the illustrated PPDU 900, four copies of U-SIG 1 are included in their corresponding OFDM symbols.

[0190] In an exemplary embodiment, when encoding the preamble 901, the source station is configured to apply different constellation mapping schemes when encoding the bit information content of U-SIG 1, U-SIG 2, RU-SIG 1, and RU-SIG 2. Fig.18 In the PPDU 900 shown, the U-SIG 1 content is encoded using binary phase shift keying (BPSK); the U-SIG 2 content is encoded using quadrature binary phase shift keying (QBPSK); the RU-SIG 1 content is encoded using quadrature binary phase shift keying (QBPSK); and the RU-SIG 2 content is encoded using binary phase shift keying (BPSK).

[0191] Fig.19Yet another frame format of an EHT LPI PPDU 950 according to another exemplary embodiment is shown, which can be used for wide BW LPI LR communication. As shown, the PPDU 950 has a greenfield format that eliminates any fields that are not specifically required by the EHT LPI enabled destination station. In this regard, the PPDU 950 does not include the traditional preamble field L-preamble / RL-SIG, nor does it include the EHT-STF field. Instead, the EHT LPI PPDU 950 is limited to the following fields: U-SIG 1, U-SIG2, RU-SIG 1, RU-SIG 2, EHT-LTF 218, and payload 404. As with the PPDU 900, the U-SIG 1 and U-SIG 2 of the PPDU 950 each encode different information, which can be the type described above with respect to the U-SIG 212 of the PPDU 200. RU-SIG-1 carries the same information as U-SIG 1, and RU-SIG-2 carries the same information as U-SIG 2. U-SIG 1, U-SIG 2, RU-SIG 1, and RU-SIG 2 are each sent using a different corresponding OFDM symbol, and each may be replicated in the frequency domain within its corresponding OFDM symbol. In at least some exemplary embodiments, all of the contents of U-SIG 1, U-SIG 2, RU-SIG 1, and RU-SIG 2 of PPDU 900 are BPSK encoded. In other exemplary embodiments, the repeated signals (RU-SIG 1 and RU-SIG 2) may use a constellation mapping scheme different from the constellation mapping scheme used for the original signals (U-SIG 1 and SIG-2), respectively, such as described above with respect to PPDU 900.

[0192] The present disclosure provides some example algorithms and calculations for implementing the examples of the disclosed methods and systems. However, the present disclosure is not constrained by any particular algorithm or calculation. Although the present disclosure describes methods and processes by steps performed in a certain order, one or more steps in the methods and processes may be appropriately omitted or changed. Where appropriate, one or more steps may be performed in an order other than the described order.

[0193] Through the description of the above embodiments, the present invention can be implemented only by hardware, can be implemented by software and necessary general hardware platforms, or can be implemented by a combination of hardware and software. Based on such understanding, the technical solution of the present invention can be embodied in the form of a software product. The software product can be stored in a non-volatile or non-transient storage medium, which can be a compact disk read-only memory (CD-ROM), a USB flash drive or a hard disk. The software product includes many instructions that enable a computer device (personal computer, server or network device) to execute the method provided in the embodiment of the present invention.

[0194] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims.

[0195] In addition, the scope of the present application is not limited to the specific embodiments of the processes, machines, manufactured products, material compositions, modules, methods and steps described in the specification. Those skilled in the art will readily appreciate from the disclosure of the present invention that processes, machines, manufactured products, material compositions, modules, methods or steps (including currently existing or later developed) that perform or achieve substantially the same functions or results as the corresponding embodiments described herein may be used in accordance with the present invention. Accordingly, the appended claims include these processes, machines, manufactured products, material compositions, modules, methods or steps.

Claims

1. A wireless network data transmission method, characterized in that: include: encoding a source word to be sent in a data unit from a source station in a wireless network; generating a first orthogonal frequency division multiplexing (OFDM) symbol, the first OFDM symbol carrying a data segment corresponding to the encoded bits of the source word; replicating the first OFDM symbol to generate a second OFDM symbol that is a linearly phase-rotated copy of the first OFDM symbol; and The data unit including the first OFDM symbol and the second OFDM symbol is transmitted.

2. The method according to claim 1, characterized in that include: mapping the coded bits to a first set of modulation symbols and a second set of modulation symbols; Among them, generating the first OFDM symbol includes: mapping the first modulation symbol set to a first frequency subcarrier set corresponding to the first OFDM symbol, mapping the second modulation symbol set to a second frequency subcarrier set corresponding to the first OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers.

3. The method according to claim 2, characterized in that Mapping the coded bits includes applying a phase rotation to the second set of modulation symbols relative to the first set of modulation symbols.

4. The method according to claim 2 or 3, characterized in that: include: duplicating the first modulation symbol set and the second modulation symbol set to provide a third modulation symbol set and a fourth modulation symbol set, wherein all four modulation symbol sets each constitute the data segment, Generating the first OFDM symbol includes: before performing the inverse fast Fourier transform operation, mapping the third modulation symbol set to a third frequency subcarrier set corresponding to the first OFDM symbol, and mapping the fourth modulation symbol set to a fourth frequency subcarrier set corresponding to the first OFDM symbol.

5. A wireless network data transmission method, characterized in that: include: encoding a source word to provide a first codeword comprising information bits of the source word and a first set of parity bits; generating a first orthogonal frequency division multiplexing (OFDM) symbol, the first OFDM symbol carrying a first data segment corresponding to the information bits of the source word and the first set of parity check bits; permuting the information bits of the source word to provide a permuted information bit set; encoding the set of permutation information bits of the source word to provide a second codeword comprising the set of permutation information bits of the source word and a second set of parity bits; generating a second OFDM symbol, the second OFDM symbol carrying a second data segment corresponding to the information bits of the source word and the second set of parity bits; as well as A data unit including the first OFDM symbol and the second OFDM symbol is transmitted in a wireless network.

6. The method according to claim 5, characterized in that include: Mapping bits of the first data segment to two corresponding sets of modulation symbols; The generating of the first OFDM symbol comprises: mapping one modulation symbol set of the modulation symbol sets to a first frequency subcarrier set of the first OFDM symbol, mapping another modulation symbol set to a second frequency subcarrier set of the first OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers of the first OFDM symbol; mapping bits of the second data segment to a first set of modulation symbols and a second set of modulation symbols; Generating the second OFDM symbol includes: mapping the first modulation symbol set to a first frequency subcarrier set of the second OFDM symbol, mapping the second modulation symbol set to a second frequency subcarrier set of the second OFDM symbol, and performing an inverse fast Fourier transform operation on the frequency subcarriers of the second OFDM symbol.

7. The method according to claim 5, characterized in that: The first codeword is a first low-density parity check LDPC codeword that conforms to a first parity check matrix, and the second codeword is a second LDPC codeword that conforms to a second parity check matrix, wherein the second parity check matrix is ​​derived by permuting the positions of columns corresponding to information bits in the first parity check matrix and copying a portion of the first parity check matrix corresponding to parity check bits.

8. A wireless network data transmission method, characterized in that: include: Generate a first low-density parity check (LPDC) codeword of a source word for a first transmission, the first LDPC codeword comprising information bits of the source word and a first set of parity check bits; permuting the information bits of the source word; as well as Generate a second LDPC codeword for retransmission, the second LDPC codeword comprising permuted information bits of the source word and a second set of parity check bits corresponding to the permuted information bits, wherein the first LDPC codeword conforms to a first parity check matrix, the second LDPC codeword conforms to a second parity check matrix, and the second parity check matrix is ​​derived by permuting positions of columns corresponding to information bits in the first parity check matrix and copying a portion of the first parity check matrix corresponding to parity check bits.

9. The method according to claim 7 or 8, characterized in that: Permuting the information bits of the source word is performed according to a predefined permutation map.

10. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 8 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1944, Z=81, and a code rate of 1 / 2 as defined by Table F-3(a) of IEEE 802.11-2020, wherein each row i=1 to 8 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

11. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 10 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1944, Z=81, and a code rate of 2 / 3 as defined by Table F-3(b) of IEEE 802.11-2020, wherein each row i=1 to 10 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

12. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1944, Z=81, and a code rate of 3 / 4 as defined by Table F-3(c) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

13. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1944, Z=81, and a code rate of 5 / 6 as defined by Table F-3(d) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

14. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 8 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1296, Z=54 and a code rate of 1 / 2 as defined by Table F-2(a) of IEEE 802.11-2020, wherein each row i=1 to 8 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

15. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 10 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1296, Z=54 and a code rate of 2 / 3 as defined by Table F-2(b) of IEEE 802.11-2020, wherein each row i=1 to 10 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

16. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1296, Z=54 and a code rate of 3 / 4 as defined by Table F-2(c) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

17. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 1296, Z=54 and a code rate of 5 / 6 as defined by Table F-2(d) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

18. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 7 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 648, Z=27 and a code rate of 1 / 2 as defined by Table F-1(a) of IEEE 802.11-2020, wherein each row i=1 to 7 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

19. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 10 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 648, Z=27 and a code rate of 2 / 3 as defined by Table F-1(b) of IEEE 802.11-2020, wherein each row i=1 to 10 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

20. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 648, Z=27 and a code rate of 3 / 4 as defined by Table F-1(c) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

21. The method according to claim 9, characterized in that The predefined permutation mapping is selected from a set of permutation mappings indexed as rows i=1 to 15 in the following table, wherein each permutation mapping corresponds to a basic LDPC parity-check code matrix for an LDPC code with a code block length of 648, Z=27 and a code rate of 5 / 6 as defined by Table F-1(d) of IEEE 802.11-2020, wherein each row i=1 to 15 defines a corresponding permutation mapping, and for each row i, the value under column position j indicates that the Z-bit set in the source word at the position corresponding to the value is to be copied to the Z-bit position of the permutation information bit of the source word at the column position corresponding to index value j:

22. A method for encoding a physical layer PHY protocol data unit PPDU for low power indoor LPI wireless communication, characterized in that: The method comprises: encoding a first set of information bits of a first universal signaling field (U-SIG 1) in a preamble of the PPDU using binary phase shift keying (BPSK), the first set of information bits comprising information about a payload of the PPDU; encoding a second set of information bits of a second universal signaling field (U-SIG 2) in the preamble of the PPDU using quadrature binary phase shift keying (QBPSK), the second set of information bits comprising further information about the payload of the PPDU; encoding the first set of information bits of a third universal signaling field (RU-SIG 1) in the preamble of the PPDU using QBPSK; encoding the second set of information bits of a fourth universal signaling field (RU-SIG 2) in the preamble of the PPDU using BPSK; and The PPDU is transmitted in a wireless network.

23. The method according to claim 22, characterized in that The BPSK-encoded first information bit set is carried in a first orthogonal frequency division multiplexing OFDM symbol, the QBPSK-encoded second information bit set is carried in a second OFDM symbol adjacent to the first OFDM symbol, the QBPSK-encoded first information bit set is carried in a third OFDM symbol adjacent to the second OFDM symbol, and the BPSK-encoded fourth information bit set is carried in a fourth OFDM symbol adjacent to the third OFDM symbol.

24. A method for assembling a physical layer PHY protocol data unit PPDU for low power indoor LPI wireless communication, characterized in that: include: Assemble a preamble of a physical layer PHY protocol data unit PPDU for low power indoor LPI wireless communication, the preamble comprising: a first universal signaling field (U-SIG 1) carrying a BPSK-encoded first set of information bits including information about a payload of the PPDU; a second universal signaling field (U-SIG 2) carrying a BPSK-encoded second set of information bits comprising further information about said payload of said PPDU; a third universal signaling field (RU-SIG 1), carrying a copy of the BPSK-encoded first set of information bits; a fourth universal signaling field (RU-SIG 2) carrying a copy of the BPSK-encoded second set of information bits; and The PPDU including the assembled preamble is transmitted in a wireless network.

25. The method according to claim 24, characterized in that The common signaling fields are each carried in a corresponding orthogonal frequency division multiplexing OFDM symbol.

26. The method according to claim 24 or 25, characterized in that The preamble is a greenfield preamble that does not include any legacy fields.

27. A wireless communication device, characterized in that: The wireless communication device comprises at least one processing unit, at least one transmitter, at least one receiver, one or more antennas, at least one non-transitory storage unit and one or more input / output interfaces; The processing unit is used to execute the method according to any one of claims 1 to 26.

28. A non-volatile computer readable medium, characterized in that: Instructions for configuring a wireless transmission station to perform a method according to any one of claims 1 to 26 are stored.

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