Patent Description:
A wireless local area network (WLAN) system connects two or more devices to each other, and typically to the Internet, in a local environment such as a home, a building, an airplane, or a campus. Currently, WLAN technology is based on the institute of electrical and electronics engineers (IEEE) <NUM> standard. The IEEE <NUM> standard has been developed into <NUM>. 11b, <NUM>. 11a, <NUM>, <NUM>. 11n, <NUM>. 11ac, and <NUM>. 11ax versions and may support a transmission speed of up to <NUM> Gbyte/s by using OFDM technology. In a typical WLAN, an access point (AP) serves as a gateway to connect user devices such as smartphones and laptops to the Internet. <CIT> proposes identification of a packet in a WLAN.

11ac, data may be simultaneously transmitted to a plurality of users through a multi-user multi-input multi-output (MU-MIMO) scheme. 11ax (referred to as high efficiency (HE)), by dividing and providing an available subcarrier to users through use of orthogonal frequency-division multiple access (OFDMA) technology as well as the MU-MIMO, multiple access is implemented. Accordingly, a WLAN system to which <NUM>. 11ax is applied may effectively support communication local areas and outdoors crowded with many users.

11be, which is referred to as extremely high throughput (EHT), is intended to support a <NUM> unlicensed frequency band, utilize a bandwidth up to <NUM> per channel, introduce a hybrid automatic repeat and request (HARQ), and support MIMO up to 16X16. With this capability, a next-generation WLAN system is expected to effectively support low latency and ultra-fast transmission with performance metrics similar to new radio (NR) <NUM> technology. <CIT> provides an example of a PPDU structure in <NUM> networks.

It is noted that the embodiments illustrated in <FIG>, <FIG>, <FIG>, <FIG>, <FIG> do not fall under the scope of protection of the present claims.

<FIG> is a diagram illustrating a wireless communication system <NUM> according to an embodiment of the inventive concept. <FIG> illustrates a wireless local area network (WLAN) system as an example of the wireless communication system <NUM>.

In specifically describing embodiments of the inventive concept, an orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiplexing access (OFDMA)-based wireless communication system, in particular, the IEEE <NUM> standard, is to be mainly described. However, the gist of the inventive concept may be applied to other communication systems with a similar technological background and channel type (for example, a cellular communication system such as long term evolution (LTE), LTE-Advanced (LTE-A), new radio (NR), wireless broadband (WiBro), or global system for mobile communication (GSM) or a short-distance communication system such as Bluetooth or near-field communication (NFC)) , through slight modification of the disclosed embodiments, which modification may be determined by one of ordinary skill in the art to which the inventive concept pertains.

Referring to <FIG>, the wireless communication system <NUM> may include first and second access points AP1 and AP2, a first station STA1, a second station STA2, a third station STA3, and a fourth station STA4. The first and second access points AP1 and AP2 may connect to a network <NUM> such as the Internet or an Internet protocol (IP) network. The first access point AP1 may provide access to the network <NUM> to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 within a first coverage area <NUM>, and the second access point AP2 may also provide access to the network <NUM> to the third and fourth stations STA3 and STA4 within a second coverage area <NUM>. According to some embodiments, the first and second access points AP1 and AP2 may communicate with at least one of the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4, based on wireless fidelity (Wi-Fi) or any other WLAN access technology.

An access point may be referred to as a router, a gateway, etc., and a station may be referred to as a mobile station, a subscriber station, a terminal, a mobile terminal, a wireless terminal, user equipment, a user, etc. The station may be a portable device, such as a mobile phone, a laptop computer, a wearable device, etc., or may be a stationary device, such as a desktop computer, a smart TV, etc. Herein, the station may be referred to as a first apparatus, and the access point may be referred to as a second apparatus or a third apparatus. Examples of the access point and the station will be described below with reference to <FIG>.

The access point may allocate at least one resource unit (RU) to at least one station. The access point may transmit data through at least one allocated resource unit, and at least one station may receive data through at least one allocated resource unit. 11ax (hereafter, HE), the access point may allocate a single resource unit to at least one station, while in <NUM>. 11be (hereafter, EHT) or next-generation IEEE <NUM> standards (hereafter, EHT+), the access point may allocate a multi-resource unit (MRU) including two or more resource units to at least one station. For example, the first access point AP1 may allocate the MRU to at least one of the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 and may transmit data through the allocated MRU.

According to some embodiments, the access point and the station may support extended range transmission. For example, a transmitter may transmit a signal including repeated patterns to a remote receiver, and, despite a weak channel condition, the receiver may identify information included in the signal with high accuracy, based on the repeated patterns. Accordingly, the first coverage area <NUM> and the second coverage area <NUM> may each be extended. As will be described later with reference to <FIG> and the like, a preamble of a physical layer protocol data unit (PPDU) may include pieces of information used to process the PPDU, and accordingly it is desirable for the pieces of information included in the preamble to be accurately transmitted to the transmitter.

As will be described below, a preamble including repeated patterns may be used for extended range transmission, and accordingly, information included in the preamble may be more accurately and reliably transmitted to a remote receiver. In addition, the receiver may accurately identify the number of repetitions of the pattern included in the preamble, and thus may accurately identify and process a pattern received from a remote transmitter. The length of the preamble including the repeated patterns may be shortened, and thus the overhead of extended range transmission may be reduced. The receiver may combine repeated patterns with each other, and thus the complexity of extended range transmission may be reduced. Due to high reliability of extended range communication, the coverage of wireless communication may be extended. For instance, in one example method, a first OFDM symbol block (at least one OFDM symbol) may be generated, which represents an encoded block sequence, e.g., original bits ("systematic bits") of the preamble, encoded using redundant bits in a forward error correction (FEC) encoding process. A second OFDM symbol block, which is a repetition of the first OFDM symbol block, may be concatenated with the first OFDM symbol block. The first and second OFDM symbol blocks may be generated in form of first and second baseband waveforms, respectively, and may be transmitted by modulating an RF carrier. The modulated RF carrier may be received at the receiver and demodulated to derive first and second received waveforms corresponding to the first and second baseband waveforms. The first and second received waveforms may be averaged, thereby generating an averaged waveform. When the averaged waveform is demodulated, de-mapped and decoded to generate corresponding bits, the encoded bits may be recovered with less errors than that achievable by processing the first waveform alone.

In an alternative example method, the first received waveform, and one or more repeated waveforms, are processed independently at the receiver to derive a first received encoded block sequence and one or more second received encoded block sequences. In a noisy / weak signal channel, the first received encoded block sequence may not be decoded successfully to recover all of the original bits. However, one of the repeated block sequences may be successfully decoded, whereby original bits may be recovered using the successfully decoded block sequence.

In another example to provide extended range operation, a first encoded block representing original bits of the preamble is repeated to generate a second encoded block, which is concatenated with the first encoded block to generate an encoded block sequence. The encoded block sequence is converted to an OFDM symbol block which is then transmitted to the receiver. When the receiver demodulates, de-maps and decodes the OFDM symbol block, it may recover two sets of decoded bits that, in the absence of any errors, would each perfectly recover the original bits. However, bit errors in one or both of the recovered sets of bits may occur in a noisy / weak signal channel. Through use of a comparison technique for the two sets of decoded bits, the BER of a resulting decoded set of bits may be reduced relative to that achievable by receiving and processing an OFDM symbol block representing just the first encoded block. As a result, the range of suitably accurate communication may be extended.

Embodiments of the inventive concept will now be described by mainly referring to EHT, but embodiments of the inventive concept may be applied to other protocol standards, for example, EHT+.

<FIG> is a block diagram of a wireless communication system <NUM> according to an embodiment of the inventive concept. <FIG> illustrates a first wireless communication apparatus <NUM> and a second wireless communication apparatus <NUM> that communicate with each other in the wireless communication system <NUM>. Each of the first and second wireless communication apparatus <NUM> and <NUM> may be any device that communicates in the wireless communication system <NUM> and may be referred to as a device for wireless communication. Each of the first and second wireless communication apparatus <NUM> and <NUM> may be an access point or a station of a WLAN system.

The first wireless communication apparatus <NUM> may include an antenna 21_2, a transceiver 21_4, and a processing circuitry 21_6. The antenna 21_2, the transceiver 21_4, and the processing circuitry 21_6 may be included in one package or may be included in different packages, respectively. The second wireless communication apparatus <NUM> may include an antenna 22_2, a transceiver 22_4, and a processing circuitry 22_6. Hereinafter, redundant descriptions of the first wireless communication apparatus <NUM> and the second wireless communication apparatus <NUM> will be omitted.

The antenna 21_2 may receive a signal from the second wireless communication apparatus <NUM> and provide the signal to the transceiver 21_4, and may transmit a signal provided from the transceiver 21_4 to the second wireless communication apparatus <NUM>. According to some embodiments, the antenna 21_2 may include a plurality of antennas for multiple input multiple output (MIMO). According to some embodiments, the antenna 21_2 may also include a phased array for beamforming.

The transceiver 21_4 may process a signal received from the second wireless communication apparatus <NUM> through the antenna 21_2 and may provide the processed signal to the processing circuitry 21_6. The transceiver 21_4 may process the signal provided from the processing circuitry 21_6 and output the processed signal through the antenna 21_2. According to some embodiments, the transceiver 21_4 may include an analog circuit such as a low noise amplifier, a mixer, a filter, a power amplifier, an oscillator, etc. According to some embodiments, the transceiver 21_4 may process a signal received from the antenna 21_2 and/or a signal received from the processing circuitry 21_6, under the control of the processing circuitry 21_6.

The processing circuitry 21_6 may extract information transmitted by the second wireless communication apparatus <NUM> by processing the signal received from the transceiver 21_4. For example, the processing circuitry 21_6 may extract information by demodulating and/or decoding the signal received from the transceiver 21_4. The processing circuitry 21_6 may generate a signal including information to be transmitted to the second wireless communication apparatus <NUM>, and provide the signal to the transceiver 21_4. For example, the processing circuitry 21_6 may provide, to the transceiver 21_4, a signal generated by encoding and/or modulating data to be transmitted to the second wireless communication apparatus <NUM>. According to some embodiments, the processing circuitry 21_6 may include a programmable component such as a central processing unit (CPU) or a digital signal processor (DSP); a reconfigurable component such as a field programmable gate array (FPGA); or a component that provides a fixed function, such as an intellectual property (IP) core. According to some embodiments, the processing circuitry 21_6 may include or access memory that stores data and/or a series of instructions.

Herein, the transceiver 21_4 and/or the processing circuitry 21_6 performing operations may be referred to as the first wireless communication apparatus <NUM> performing the corresponding operations. Accordingly, operations performed by the access point may be performed by a transceiver and/or processing circuitry included in the access point, and operations performed by the station may be performed by a transceiver and/or processing circuitry included in the station.

<FIG> is a diagram of a PPDU according to an embodiment. In detail, <FIG> illustrates a structure of an EHT MU PPDU. High efficiency (HE) may define a HE MU PPDU and a HE single user (SU) PPDU, but an extremely high throughput (EHT) may not define the EHT SU PPDU and transmit the EHT MU PPDU to a single user. The EHT MU PPDU may be set in a compressed mode or a non-compressed mode and may include OFDM symbols in the non-compressed mode.

Referring to <FIG>, the EHT MU PPDU may include a preamble including training fields and signaling fields and a payload including a data field. In the preamble, the EHT MU PPDU may include a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG) field, a repeated legacy-signal (RL-SIG) field, a universal signal (U-SIG) field, an EHT-SIG field, an extremely high throughput-short training field (EHT-STF), and an extremely high throughput-long training field (EHT-LTF). The EHT MU PPDU may include a data field and a packet extension (PE) field in the payload. Herein, the U-SIG field may be simply expressed as a U-SIG, and may be interchangeably referred to as a "first signal field". The EHT-SIG field may be simply expressed as an EHT-SIG, and may be interchangeably referred to as a second signal field. Herein, the term "signal field" refers to a field within a data unit, that is utilized at the receiver to properly identify and decode data included within the data unit.

The L-STF may include a short training OFDM symbol and may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency/time synchronization. The L-LTF may include a long training OFDM symbol and may be used for fine frequency/time synchronization and channel estimation. The L-SIG field may be used to transmit control information, and may include information regarding a data rate and a data length. According to some embodiments, the L-SIG field may be repeated in the RL-SIG field.

The U-SIG field (or the U-SIG) may include control information common to at least one station receiving the EHT MU PPDU, and may correspond to HE-SIG-A of the HE. For example, as shown in <FIG>, the U-SIG field may include version-independent fields and version-dependent fields. According to some embodiments, the U-SIG field may further include fields and reserved bits that respectively correspond to a cyclic redundancy check (CRC) and a tail. The version-independent fields may include static locations and bit definition in different generations and/or physical versions. According to some embodiments, differently from the EHT-SIG field described below, the U-SIG field may be modulated according to a single modulation scheme, for example, binary phase-shift keying (BPSK). An example of the U-SIG field will be described below with reference to <FIG>.

The EHT-SIG field may have a variable modulation coding scheme (MCS) and length and may correspond to HE-SIG-B of the HE. For example, as shown in <FIG>, when the EHT MU PPDU is transmitted to multiple users, the EHT-SIG field may include a common field including common control information and a user specific field including control information dependent on a user. As shown in <FIG>, the U-SIG field may have a fixed length (e.g., about <NUM>), but the EHT-SIG field may have a variable length. The common field may include a U-SIG overflow, the total number of non-OFDMA users, and a RU allocation subfield (RUA). A user specific field for the non-MU MIMO may include an STA-ID subfield, an MCS subfield, an NSTS subfield, a Beamformed subfield, and a coding subfield, and a user specific field for the MU-MIMO may include an STA-ID subfield, an MCS subfield, a coding subfield, and a spatial configuration subfield. According to some embodiments, the EHT-SIG field may be modulated according to one of two or more modulation schemes such as BPSK and quadrature binary phase shift keying (QBPSK).

<FIG> is a diagram of a U-SIG field according to an embodiment. In detail, <FIG> illustrates a U-SIG field included in the EHT MU PPDU, and, as described above with reference to <FIG>, the U-SIG field may be followed by the EHT-SIG field.

Referring to <FIG>, the U-SIG field may include U-SIG-<NUM> and U-SIG-<NUM>. U-SIG-<NUM> and the U-SIG-<NUM> may correspond to two OFDM symbols, respectively, and each of the U-SIG-<NUM> and the U-SIG-<NUM> may correspond to <NUM> bits as illustrated in <FIG>. The U-SIG-<NUM> may include version-independent fields such as a <NUM>-bit physical version identifier field, a <NUM>-bit bandwidth field, a <NUM>-bit uplink/downlink (UL/DL) field, a <NUM>-bit BSS color field, a <NUM>-bit TXOP field, and a <NUM>-bit validate field. The U-SIG-<NUM> may include version-dependent fields such as a <NUM>-bit PPDU type and compression mode field, a <NUM>-bit punctured channel information field, a <NUM>-bit EHT-SIG MCS field, a <NUM>-bit EHT-SIG symbol number field, a <NUM>-bit CRC field, and a <NUM>-bit tail field. The PPDU type and compression mode field will be described below with reference to <FIG>, and the punctured channel information field will be described below with reference to <FIG>.

<FIG> is a table showing encoding of a PPDU type and compression mode field, according to an embodiment. The table of <FIG> shows a UL/DL field included in the U-SIG-<NUM> of the U-SIG field of <FIG> together with the PPDU type and compression mode field included in the U-SIG-<NUM> of the U-SIG field of <FIG>. As described above with reference to <FIG>, the UL/DL field may have a <NUM>-bit length, and the PPDU type and compression mode field may have a <NUM>-bit length. Herein, the PPDU type and compression mode field may be simply referred to as a mode field.

Referring to <FIG>, the UL/DL field may indicate a UL or a DL, and the PPDU type and compression mode field may indicate which mode the PPDU supports. As shown in <FIG>, when the value of the PPDU type and compression mode field is <NUM>, the PPDU may be based on OFDMA. When the value of the PPDU type and compression mode field is <NUM>, the PPDU may be configured for a SU or a null data packet (NDP). When the value of the PPDU type and compression mode field is <NUM> in the DL, the PPDU may be configured for a MU MIMO based on non-OFDMA. In other words, when the value of the PPDU type and compression mode field is <NUM>, the PPDU may be based on OFDMA, and when the PPDU type and compression mode field has a value other than <NUM>, the PPDU may be based on OFDM.

<FIG> is a table showing encoding of a punctured channel information field according to an embodiment. The table of <FIG> shows puncturing patterns indicated by the punctured channel information field in non-OFDMA. As described above with reference to <FIG>, the punctured channel information field may be included in the U-SIG-<NUM> of the U-SIG field and may have a <NUM>-bit length.

Referring to <FIG>, puncturing may not be performed in bandwidths of <NUM> and <NUM>, and a value of the punctured channel information field may be <NUM>. The value of the punctured channel information field in a bandwidth of <NUM> may be one of <NUM> to <NUM> according to a puncturing pattern, the value of the punctured channel information field in a bandwidth of <NUM> may be one of <NUM> to <NUM> according to a puncturing pattern, and the value of the punctured channel information field in a bandwidth of <NUM> may be one of <NUM> to <NUM> according to a puncturing pattern. As a result, the punctured channel information field in the non-OFDMA may have a value between <NUM> and <NUM>, and <NUM> bits of the punctured channel information field may be all used to indicate the puncturing patterns. Unlike the table of <FIG>, <FIG> bits respectively indicating <NUM> frequency subblocks from among <NUM> bits of the punctured channel information field may be used in OFDMA, and the other bit may not be used in OFDMA.

<FIG> are diagrams of EHT-SIG content channels according to embodiments. <FIG> illustrates an EHT-SIG content channel format for OFDMA transmission in a bandwidth of <NUM>, <NUM>, or <NUM>, <FIG> illustrates an EHT-SIG content channel format for the OFDMA transmission in a bandwidth of <NUM>, and <FIG> illustrates an EHT-SIG content channel format for the OFDMA transmission in a bandwidth of <NUM>. <FIG> illustrates an EHT-SIG content channel format for non-OFDMA transmission to multiple users, <FIG> illustrates an EHT-SIG content channel format for the non-OFDMA transmission to a single user, and <FIG> illustrates an EHT-SIG content channel format for an EHT sounding NDP.

The EHT-SIG field may include information necessary or desirable for stations to decode the EHT MU PPDU along with the U-SIG field. For example, in the EHT MU PPDU, the EHT-SIG field may include U-SIG overflow bits that are information commonly applied to all stations. The EHT-SIG field may include resource allocation information that a user uses to decode data by using a RU or a MRU allocated to the user. The EHT-SIG field for the EHT MU PPDU may have one EHT-SIG content channel in the bandwidth of <NUM>, the EHT-SIG field for the EHT MU PPDU may have two EHT-SIG content channels in the bandwidth of <NUM> or <NUM>, and the EHT-SIG field for the EHT MU PPDU may have two EHT-SIG content channels in every <NUM> frequency subblock in the bandwidth of <NUM> or <NUM>. Examples of the EHT-SIG content channels according to the bandwidths will be described below with reference to <FIG> and <FIG>.

As described above with reference to <FIG>, the EHT-SIG field may have different structures depending on modes defined according to values of the UL/DL field and the PPDU type and compression mode field of the U-SIG field, for example, DL OFDMA transmission, DL non-OFDMA transmission to multiple users, the non-OFDMA transmission to a single user, or the EHT sounding NDP.

Referring to <FIG>, when the value of the UL/DL field is <NUM> and the value of the PPDU type and compression mode field is <NUM>, a PPDU for DL OFDMA transmission may be defined. When the bandwidth of the PPDU is equal to or greater than <NUM> in the DL OFDMA transmission, user fields may be split across content channels according to the common field in each EHT-SIG content channel, and this split may be referred to as a dynamic split.

Referring to <FIG>, when the value of the UL/DL field is <NUM> and the value of the PPDU type and compression mode field is <NUM>, a PPDU for the DL non-OFDMA transmission to multiple users may be defined. When the bandwidth of the PPDU is equal to or greater than <NUM> in the DL non-OFDMA transmission to multiple users, the user fields may be split across the EHT-SIG content channels, and this split may be referred to as an equitable split.

Referring to <FIG>, when the value of the UL/DL field is <NUM> or <NUM> and the value of the PPDU type and compression mode field is <NUM>, a PPDU for the non-OFDMA transmission to a single user may be defined. When the bandwidth of the PPDU is equal to or greater than <NUM> in the non-OFDMA transmission to a single user, only the user field may be repeated across the EHT-SIG content channels. The common field and one user field may be encoded into one block in <FIG> and <FIG>, and one encoding block will be described below with reference to <FIG>.

Referring to <FIG>, when the value of the UL/DL field is <NUM> or <NUM> and the value of the PPDU type and compression mode field is <NUM>, a PPDU for the EHT sounding NDP may be defined. In the EHT sounding NDP, a user field may be omitted.

<FIG> are diagrams of common fields according to embodiments. As described above with reference to <FIG>, the common fields may be included in the EHT-SIG field.

Referring to <FIG>, in an OFDMA transmission mode, a common field of the EHT-SIG field may include a <NUM>-bit spatial reuse subfield, a <NUM>-bit GI+LTF size subfield, a <NUM>-bit number of EHT-LTF symbols subfield, a <NUM>-bit LDPC extra symbol segment subfield, a <NUM>-bit Pre-FEC padding factor subfield, a <NUM>-bit PE disambiguity subfield, an Nx9-bit RU allocation-<NUM> subfield, a <NUM>-bit CRC-<NUM> subfield, a <NUM>-bit tail-<NUM> subfield, an Mx9-bit RU allocation-<NUM> subfield, a <NUM> or <NUM>-bit CRC-<NUM> subfield, and a <NUM> or <NUM>-bit tail-<NUM> subfield.

When a value of a BW field of the U-SIG field is <NUM> or <NUM>, e.g., when a bandwidth is <NUM> or <NUM>, N may be <NUM> (N=<NUM>), and, when the value of the BW field is <NUM>, <NUM>, <NUM>, or <NUM>, e.g., when the bandwidth is <NUM>, <NUM>, or <NUM>, N may be <NUM> (N=<NUM>). When the value of the BW field of the U-SIG field is <NUM>, <NUM>, or <NUM>, e.g., when the bandwidth is <NUM>, <NUM>, or <NUM>, M may be <NUM> (M=<NUM>), and the RU allocation-<NUM> subfield may be omitted in the common field. When the value of the BW field is <NUM>, e.g., when the bandwidth is <NUM>, M may be <NUM> (M=<NUM>), and, when the value of the BW field is <NUM> or <NUM>, e.g., when the bandwidth is <NUM>, M may be <NUM> (M=<NUM>). When the RU allocation-<NUM> subfield is omitted, the CRC-<NUM> subfield and the tail-<NUM> subfield may each have <NUM> bits and may be omitted in the common field.

Among the subfields included in the common field, the RU allocation subfield may indicate RU allocation information regarding a <NUM> sub-channel (e.g., information regarding an RU type and the number of users supported). Accordingly, as the bandwidth increases, the number of RU allocation subfields in the common field may increase, and user fields, the number of which is the same as the number of users indicated by the RU allocation sub-fields, may be included in the user specific field of the content channel.

Referring to <FIG>, in a non-OFDMA transmission mode, a common field of the EHT-SIG field may include a <NUM>-bit spatial reuse subfield, a <NUM>-bit GI+LTF size subfield, a <NUM>-bit number of EHT-LTF symbols subfield, a <NUM>-bit LDPC extra-symbol segment subfield, a <NUM>-bit Pre-FEC padding factor subfield, a <NUM>-bit PE disambiguity subfield, and a <NUM>-bit number of non-OFDMA users subfield. In the non-OFDMA transmission mode, the user specific field of the content channel may include user fields, the number of which is indicated by a value of the <NUM>-bit number of non-OFDMA users subfield.

Referring to <FIG>, in the EHT sounding NDP mode, a common field of the EHT-SIG field may include the <NUM>-bit spatial reuse subfield, the <NUM>-bit GI+LTF size subfield, the <NUM>-bit number of EHT-LTF symbols subfield, a <NUM>-bit number of spatial streams (NSS) subfield, the <NUM>-bit beamformed subfield, a <NUM>-bit CRC subfield, and a <NUM>-bit tail subfield. The value of the NSS subfield may indicate the number of spatial streams, for example, a maximum of eight spatial streams.

<FIG> and <FIG> are diagrams of examples of a block including a user field, according to embodiments. <FIG> illustrates an encoding block including a common field and a user field, and <FIG> illustrates a user block field.

The user specific field may include <NUM> or at least one user block field and may have different features depending on modes. For example, in the OFMDA transmission mode, each non-final user block may include two user fields including information for two stations used to decode payloads. In the OFMDA transmission mode, a final user block field may include information for one user or two users which is dependent on the number of users in the EHT-SIG content channel, and the number of user fields may be presented by the RU allocation subfields. In the non-OFDMA transmission mode, the user block field may be configured in the same way as the OFDMA transmission by using other user fields than a first user field. In the non-OFDMA transmission mode, the first user field may configure an encoding block together with the common field, and the number of user fields may be presented in the number of non-OFDMA users subfield. The EHT sounding NDP may not include a user field.

Referring to <FIG>, the common field and the user field may be included in one encoding block. For example, as described above with reference to <FIG> and <FIG>, in the PPDU for the DL non-OFDMA transmission to multiple users or the non-OFDMA transmission to a single user, the common field and the first user field may be included in one block(a "first encoding block"). As shown in <FIG>, the encoding block may include a <NUM>-bit common field, a <NUM>-bit user field, a <NUM>-bit CRC field, and a <NUM>-bit tail field.

Referring to <FIG>, the user block field may include an Nx22-bit user field, a <NUM>-bit CRC field, and a <NUM>-bit tail field. In <FIG>, N may correspond to the number of user fields. For example, when only one user exists in the final user block field, N may be <NUM> (N=<NUM>), but in other cases, N may be <NUM>.

<FIG> are diagrams of examples of a user field according to embodiments. <FIG> illustrates a user field in non-MU-MIMO allocation, and <FIG> illustrates a user field in MU-MIMO allocation.

Referring to <FIG>, in the non-MU-MIMO allocation, the user field may have a <NUM>-bit length. As shown in <FIG>, in the non-MU-MIMO allocation, the user field may include an <NUM>-bit STA-ID subfield, a <NUM>-bit MCS subfield, a <NUM>-bit Number of Space-Time Streams (NSTS) subfield, a <NUM>-bit beamformed subfield, and a <NUM>-bit coding subfield.

Referring to <FIG>, in the MU-MIMO allocation, the user field may have a <NUM>-bit length. As shown in <FIG>, in the MU-MIMO allocation, the user field may include an <NUM>-bit STA-ID subfield, a <NUM>-bit MCS subfield, a <NUM>-bit coding subfield, and a <NUM>-bit spatial configuration subfield.

<FIG> are diagrams of examples of an EHT-SIG content channel for transmission to multiple users, according to embodiments. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the OFDMA transmission and the non-OFDMA transmission to multiple users. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the OFDMA transmission and the non-OFDMA transmission to multiple users. <FIG> illustrates an EHT-SIG content channel for an <NUM> PPDU for the OFDMA transmission and the non-OFDMA transmission to multiple users. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the OFDMA transmission and the non-OFDMA transmission to multiple users.

Referring to <FIG>, in the OFDMA transmission mode or non-OFDMA transmission mode for multiple users, the EHT-SIG content channel may have a duplicated structure in a frequency axis. For example, in the OFDMA transmission mode, the EHT-SIG content channel may have different pieces of information in every <NUM> frequency subblock. In the non-OFDMA transmission mode for multiple users, the EHT-SIG content channel may have different pieces of information in every <NUM> frequency subblock.

<FIG> are diagrams of examples of an EHT-SIG content channel for transmission to a single user or a sounding NDP, according to embodiments. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the non-OFDMA transmission to a single user or the EHT sounding NDP. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the non-OFDMA transmission to a single user or the EHT sounding NDP. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the non-OFDMA transmission to a single user or the EHT sounding NDP. <FIG> illustrates an EHT-SIG content channel for a <NUM> PPDU for the non-OFDMA transmission to a single user or the EHT sounding NDP.

Referring to <FIG>, in the non-OFDMA transmission mode for a single user, the EHT-SIG content channel may have the same information in every <NUM> frequency subblock. In the non-OFDMA transmission mode for a single user or an EHT sounding NDP mode, one EHT-SIG content channel may be duplicated in every <NUM> frequency subblock, regardless of bandwidths.

<FIG> are diagrams of examples of a PPDU according to embodiments. <FIG> illustrates a structure of an EHT extended range (ER) PPDU, and <FIG> illustrates a structure of an EHT ER sounding NDP. EHT may support an ER for a transmitter and a receiver far away from each other. As described above with reference to <FIG>, in the ER, the transmitter may transmit repeated patterns to the receiver, and the receiver may improve a reception rate by combining the repeated patterns with each other. Redundant descriptions between <FIG> and descriptions of <FIG> that are the same as given above with reference to <FIG> will be omitted.

Referring to <FIG>, the EHT ER PPDU may include an L-STF field, an L-LTF field, an L-SIG field, an RL-SIG field, a U-SIG field, an EHT-SIG field, an EHT-STF field, and an EHT-LTF field in a preamble. The EHT ER PPDU may include a data field and a PE field in a payload. Compared with the EHT MU PPDU of <FIG>, the U-SIG field and the EHT-SIG field in the EHT ER PPDU may be extended. In other words, the U-SIG field and the EHT-SIG field in the ER may each include repeated patterns. According to some embodiments, the EHT ER PPDU of <FIG> may be used in the DL MU OFDMA transmission mode, the DL MU non-OFDMA transmission mode, and the SU non-OFDMA transmission mode. Examples of the U-SIG field and the EHT-SIG field in the ER will be described below with reference to drawings.

Referring to <FIG>, the EHT ER sounding NDP may include an L-STF field, an L-LTF field, an L-SIG field, an RL-SIG field, a U-SIG field, an EHT-SIG field, an EHT-STF field, and a n EHT-LTF field in a preamble. The EHT ER sounding NDP may include a data field and a PE field in a payload. As shown in <FIG>, the data field may be omitted from the EHT ER sounding NDP, and, similar to the EHT ER PPDU of <FIG>, the EHT ER sounding NDP may include an extended U-SIG field and an extended EHT-SIG field. To estimate an extended range channel, the EHT ER sounding NDP of <FIG> may be used.

<FIG> is a diagram of a U-SIG field according to an embodiment. <FIG> illustrates the U-SIG field included in the EHT ER PPDU, and, as described above with reference to <FIG>, the U-SIG field may be followed by the EHT-SIG field. Descriptions of <FIG> that are the same as given above with reference to <FIG> will be omitted.

As shown in <FIG>, the U-SIG field may include U-SIG-<NUM>, U-SIG-<NUM>-R, U-SIG-<NUM>, and U-SIG-<NUM>-R. The U-SIG-<NUM>, the U-SIG-<NUM>-R, the U-SIG-<NUM>, and the U-SIG-<NUM>-R may correspond to four OFDM symbols, respectively, and may correspond to <NUM> bits, as shown in <FIG>. The U-SIG-<NUM> may include version-independent fields such as a <NUM>-bit physical version identifier field, a <NUM>-bit bandwidth field, a <NUM>-bit UL/DL field, a <NUM>-bit BSS color field, and a <NUM>-bit TXOP field. Compared with the U-SIG-<NUM> of <FIG>, a valid bit may be omitted from the U-SIG-<NUM> of <FIG>. The U-SIG-<NUM> may include version-dependent fields such as a <NUM>-bit PPDU version and compression mode field, a <NUM>-bit CRC field, and a <NUM>-bit tail field. Compared with the U-SIG-<NUM> of <FIG>, a punctured channel information field, an EHT-SIG MCS field, and a number of EHT-SIG symbols field may be omitted from the U-SIG-<NUM> of <FIG>.

The U-SIG-<NUM>-R following the U-SIG-<NUM> may include the same fields as the U-SIG-<NUM>, and the U-SIG-<NUM>-R following the U-SIG-<NUM> may include the same fields as the U-SIG-<NUM>. In other words, the U-SIG in the ER may include repeated patterns, and accordingly may have an extended length (for example, <NUM>). As will be described later with reference to <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R may be modulated according to different modulation schemes, and the U-SIG-<NUM> and the U-SIG-<NUM>-R may be modulated according to the same modulation schemes.

<FIG> is a table showing encoding of a PPDU type and compression mode field, according to an embodiment. The table of <FIG> shows a UL/DL field included in the U-SIG-<NUM> of the U-SIG field of <FIG> together with the PPDU type and compression mode field included in the U-SIG-<NUM> of the U-SIG field of <FIG>. As described above with reference to <FIG>, the UL/DL field may have a <NUM>-bit length, and the PPDU type and compression mode field may have a <NUM>-bit length.

For not only a single user but also multiple users in the DL, the ER may support transmission modes such as SU transmission, DL OFDMA transmission, and non-OFDMA MU-MIMO transmission. An ER sounding NDP mode may be required to measure a channel between an access point and a station far away from each other. According to some embodiments, the aforementioned modes in the ER may be defined in the table of <FIG>.

Referring to <FIG>, the UL/DL field may indicate a UL or a DL, and the PPDU type and compression mode field may indicate which mode the PPDU supports. As shown in <FIG>, when the value of the PPDU type and compression mode field in the DL is <NUM>, the PPDU may be for ER DL OFDMA. When the value of the PPDU type and compression mode field in the DL is <NUM>, the PPDU may be for ER SU or ER NDP. When the value of the PPDU type and compression mode field in the DL is <NUM>, the PPDU may be for ER DL MU-MIMO. When the value of the PPDU type and compression mode field in the UL is <NUM>, the PPDU may be for ER SU or ER NDP.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment. As shown in <FIG>, the method for extended range transmission may include a plurality of operations S100 through S600. It is assumed in <FIG> that an access point <NUM> and a station <NUM> communicate with each other in an ER.

Referring to <FIG>, in operation S100, the access point <NUM> may generate a U-SIG field. As described above with reference to <FIG>, in the ER, the access point <NUM> may generate a U-SIG field including repeated patterns and having an extended length. The U-SIG field may include information used to process a PPDU transmitted to the station <NUM> in operation S300, which will be described later. According to some embodiments, the U-SIG field may include information used by the station <NUM> to process an EHT-SIG field generated in operation S200, which will be described later. An example of operation S100 will be described later with reference to <FIG>.

In operation S200, the access point <NUM> may generate the EHT-SIG field. As described above with reference to <FIG>, in the ER, the access point <NUM> may generate a EHT-SIG field including repeated patterns and having an extended length. The EHT-SIG field may include information used to process the PPDU transmitted to the station <NUM> in operation S300, which will be described later. Examples of operation S200 will be described later with reference to <FIG> and <FIG>.

In operation S300, the access point <NUM> may transmit the PPDU, and the station <NUM> may receive the PPDU. For example, the PPDU may include the U-SIG field generated in operation S100 and the EHT-SIG field generated in operation S200. According to some embodiments, the PPDU transmitted in operation S300 may be the EHT ER PPDU described above with reference to <FIG>.

In operation S400, the station <NUM> may extract the U-SIG field from the PPDU and may identify first information from the U-SIG field. According to some embodiments, as will be described later with reference to <FIG>, the station <NUM> may identify that the PPDU supports the ER, while extracting the U-SIG field. The first information included in the U-SIG field may include information to be used for processing the PPDU. For example, the first information may include information to be used for extracting and processing the EHT-SIG field following the U-SIG field. Examples of operation S400 will be described later with reference to <FIG> and <FIG>.

In operation S500, the station <NUM> may extract the EHT-SIG field from the PPDU and may identify second information from the EHT-SIG field. According to some embodiments, the station <NUM> may identify information about the repeated patterns from the EHT-SIG field, based on the first information identified in operation S400, and may extract the EHT-SIG field from the PPDU, based on the identified information. The second information included in the EHT-SIG field may include information to be used for processing the PPDU, together with the first information identified in operation S400. Examples of operation S500 will be described later with reference to <FIG>, <FIG>, and <FIG>.

In operation S600, the station <NUM> may process the PPDU. The station <NUM> may obtain necessary information by processing the PPDU, based on the first information identified in operation S400 and the second information identified in operation S500. For example, the station <NUM> may identify a user field allocated to the station <NUM>, based on the first information and the second information, and may identify data provided by the access point <NUM> to the station <NUM> from the identified user field.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment, and <FIG> is a diagram illustrating a U-SIG field according to an embodiment. The flow diagram of <FIG> illustrates examples of operation S100 and operation S400, and an upper portion of <FIG> illustrates a U-SIG field included in an EHT MU PPDU or EHT TB PPDU and a lower portion of <FIG> illustrates an extended U-SIG field included in a PPDU in an ER, namely, an EHT ER PPDU or EHT ER sounding NDP. As described above with reference to <FIG>, in operation S100' of <FIG>, a U-SIG field may be generated, and, in operation S400' of <FIG>, a U-SIG field may be extracted, and first information may be identified from the U-SIG field. <FIG> and <FIG> will now be described with reference to <FIG>.

Referring to <FIG>, operation S100' may include operation S110 and operation S120. In operation S110, an access point <NUM> may generate U-SIG-<NUM> and U-SIG-<NUM>-R from first encoded bits. As described above with reference to <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R, which are patterns repeated in the U-SIG field, may commonly correspond to fields including information. Accordingly, the access point <NUM> may generate the first encoded bits by encoding a bitstream including the values of fields corresponding to the U-SIG-<NUM>, based on, for example, forward error correction (FEC), and may generate the U-SIG-<NUM> and the U-SIG-<NUM>-R from the first encoded bits.

Referring to the upper portion of <FIG>, in the EHT MU PPDU or EHT TB PPDU, the access point <NUM> may generate the U-SIG-<NUM> and the U-SIG-<NUM> according to the same modulation schemes. For example, as shown in <FIG>, the access point <NUM> may generate the U-SIG-<NUM> and the U-SIG-<NUM> from encoded bits, based on binary phase-shift keying (BPSK).

Referring to the lower portion of <FIG>, in the ER, the access point <NUM> generates the U-SIG-<NUM> and the U-SIG-<NUM>-R according to different modulation schemes. For example, as shown in <FIG>, the access point <NUM> may generate the U-SIG-<NUM>, based on BPSK, and may generate the U-SIG-<NUM>-R, based on quadrature binary phase shift keying (QBPSK). Accordingly, a station <NUM> may easily identify whether the PPDU including the U-SIG field has a format supporting the ER, according to a modulation scheme of a symbol (i.e., the U-SIG-<NUM> or U-SIG-<NUM>-R) following the U-SIG-<NUM>.

Returning to <FIG>, in operation S120, the access point <NUM> may generate U-SIG-<NUM> and U-SIG-<NUM>-R from second encoded bits. As described above with reference to <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R, which are patterns repeated in the U-SIG field, may commonly correspond to fields including information. Accordingly, the access point <NUM> may generate the second encoded bits by encoding a bitstream including the values of fields corresponding to the U-SIG-<NUM>, based on, for example, FEC, and may generate the U-SIG-<NUM> and the U-SIG-<NUM>-R from the second encoded bits.

Referring to the lower portion of <FIG>, in the ER, the access point <NUM> generates the U-SIG-<NUM> and the U-SIG-<NUM>-R according to the same modulation scheme. For example, as shown in <FIG>, the access point <NUM> may generate the U-SIG-<NUM> and the U-SIG-<NUM>-R according to BPSK. As described above, the U-SIG-<NUM>-R modulated according to QBPSK may be used in order to indicate the EHT ER PPDU or the EHT ER sounding NDP, and the U-SIG-<NUM>-R may be modulated according to BPSK, similar to the U-SIG-<NUM>. As described above with reference to <FIG>, the access point <NUM> may generate the U-SIG field sequentially including the U-SIG-<NUM>, the U-SIG-<NUM>-R, the U-SIG-<NUM>, and the U-SIG-<NUM>-R.

Returning to <FIG>, operation <NUM>' may include a plurality of operations S410 through S430. In operation S410, the station <NUM> may identify the U-SIG-<NUM> and the U-SIG-<NUM>-R. As described above, the U-SIG-<NUM>-R may be modulated according to a different modulation scheme (for example, QBPSK) from the modulation scheme of the U-SIG-<NUM> (for example, BPSK). When a modulation scheme of a symbol following the U-SIG-<NUM> is different from the modulation scheme of the U-SIG-<NUM>, the station <NUM> may identify that the symbol following the U-SIG-<NUM> is the U-SIG-<NUM>-R, and may identify the EHT ER PPDU or EHT ER sounding NDP including the extended U-SIG field.

In operation S420, the station <NUM> may generate a common encoded block. As described above, the U-SIG-<NUM> and the U-SIG-<NUM>-R may commonly correspond to fields, and accordingly, the station <NUM> may generate a common encoded block by combining an encoded block derived from the U-SIG-<NUM> with an encoded block derived from the U-SIG-<NUM>-R.

In operation S430, the station <NUM> may identify a repetition number of a pattern, which is a number of times that the pattern is repeated. For example, the station <NUM> may obtain information related to the repetition number of a pattern by decoding the common encoded block generated in operation S420, and may identify the repetition number of a pattern, based on the obtained information. According to some embodiments, as will be described later with reference to <FIG>, the U-SIG field may include a field indicating the repetition number of a pattern. According to some embodiments, as will be described later with reference to <FIG>, the U-SIG field may include a field implicitly indicating the repetition number of a pattern.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment, and <FIG> are diagrams illustrating examples of an EHT-SIG content channel for extended range transmission, according to embodiments. The flow diagram of <FIG> illustrates examples of operation S200 and operation S500 of <FIG>, and <FIG> illustrate examples of the EHT-SIG content channel used in <FIG>. As described above with reference to <FIG>, in operation S200a of <FIG>, an EHT-SIG field may be generated, and, in operation S500a of <FIG>, an EHT-SIG field may be extracted, and second information may be identified from the EHT-SIG field. <FIG>, <FIG> will now be described with reference to <FIG>.

Referring to <FIG>, operation S200a may include a plurality of operations S210a, S230a, S250a, S270a, and S290a. In operation S210a, an access point <NUM> generates a bitstream. For example, the access point <NUM> may generate a bitstream including the values of the EHT-SIG content channel. According to some embodiments, a structure of the EHT-SIG field of the EHT ER PPDU may be the same as or similar to that of an EHT-SIG field according to each transmission mode in the EHT MU PPDU. Overlapping of the EHT-SIG content channel according to bandwidths even in the EHT ER PPDU may be the same as or similar to that defined according to each transmission mode in the EHT MU PPDU. For example, the bitstream may include the values of a common field and a user field of the EHT-SIG field. The bitstream may include a series of bits, and each of the bits may have a valid meaning in a field (or subfield) to which each of the bits belongs. An example of operation S210a will be described later with reference to <FIG>.

In operation S230a, the access point <NUM> generates an encoded block from the bitstream. For example, the access point <NUM> may generate the encoded block by encoding the bitstream according to FEC. According to some embodiments, the access point <NUM> may generate the encoded block according to channel coding based on binary convolution coding (BCC) and/or low-density parity-check (LDPC). When BCC is used, a BCC interleaver may be applied to the encoded block.

In operation S250a, the access point <NUM> generates a modulated block from the encoded block. For example, the access point <NUM> may generate the modulated block from the encoded block generated in operation S230a, by performing constellation mapping according to a predefined modulation scheme.

In operation S270a, the access point <NUM> generates an OFDM symbol block from the modulated block. According to some embodiments, the access point <NUM> may sequentially map the modulated block generated in operation S250a with at least one OFDM symbol, and thus may generate an OFDM symbol block including the at least one OFDM symbol. For example, as shown in <FIG>, the access point <NUM> may generate N OFDM symbols (where N is an integer greater than <NUM>) from a modulated block generated from the EHT-SIG content channel including the common field and the user specific field. (Here, "modulated block" may refer to a digital modulation technique involving mapping of a constellation point of an I-Q graph to a complex value of a sub-carrier. ) Herein, an OFDM symbol corresponding to the EHT-SIG field may be referred to as an EHT-SIG OFDM symbol, and an OFDM symbol block including the EHT-SIG OFDM symbol may be referred to as an EHT-SIG OFDM symbol block. It is noted that in the description herein involving OFDM technology, phrases such as "modulated block" and "OFDM symbol modulated from encoded bits" may refer to a digital modulation technique involving mapping of a constellation point of an I-Q graph to a complex value of a sub-carrier. Thus, the OFDM techniques discussed herein may involve two phases of modulation. The first modulation phase involves mapping each group of the encoded bits to an I-Q graph constellation point and in turn digitally modulating a subcarrier, in conjunction with an IFFT process with multiple values for subcarriers used as input data. This generates an OFDM symbol (in the form of a baseband waveform) that represents the encoded bits, and thus the OFDM symbol may be said to be "modulated from the encoded bits". The second modulation phase may involve modulating an RF carrier with the OFDM symbol and transmitting the modulated RF carrier.

Returning to <FIG>, in operation S290a, the access point <NUM> generates the EHT-SIG field by repeating the OFDM symbol block. According to some embodiments, as shown in <FIG>, the access point <NUM> may generate an EHT-SIG field (i.e., an extended EHT-SIG field) by repeating an EHT-SIG OFDM symbol block including N EHT-SIG OFDM symbols at least once. According to some embodiments, as shown in <FIG>, the access point <NUM> may generate an EHT-SIG field (i.e., an extended EHT-SIG field) by repeating the EHT-SIG OFDM symbol block including the N EHT-SIG OFDM symbols n times (where n is an integer greater than <NUM>). In other words, in the examples of <FIG>, <FIG>, a pattern repeated in the EHT-SIG field of the EHT ER PPDU may be the EHT-SIG OFDM symbol block.

Returning to <FIG>, in operation S500a, a station <NUM> may identify the repeated OFDM symbol blocks. For example, the station <NUM> may receive the EHT ER PPDU including the extended EHT-SIG field from the access point <NUM>, and may identify the repeated OFDM symbol blocks from the EHT-SIG field of the EHT ER PPDU (where "repeated symbol blocks" refers to the first symbol block in the EHT-SIG field and the one or more repetitions of the first symbol block in the EHT-SIG field). The station <NUM> may combine the repeated OFDM symbol blocks with each other and accordingly may improve a decoding success rate of information provided by the access point <NUM> through the EHT-SIG field. For instance, as mentioned earlier, one example of combining the repeated OFDM symbol blocks may be as follows: The first OFDM symbol block (at least one OFDM symbol) may represent an encoded block sequence, e.g., original bits that are encoded using redundant bits in an FEC encoding process. The one or more repetitions of the first OFDM symbol block may be concatenated with the first OFDM symbol block. The first and repetitive OFDM symbol blocks may be generated in the form of first and second baseband waveforms, respectively, and may be transmitted by modulating an RF carrier. The modulated RF carrier may be received at the receiver and demodulated to derive first and second received waveforms corresponding to the first and second baseband waveforms. The first and second received waveforms may be averaged, thereby generating an averaged waveform. When the averaged waveform is demodulated, de-mapped and decoded to generate corresponding bits, the encoded bits may be recovered with fewer errors than that achievable by processing the first waveform alone.

<FIG> is a flowchart depicting an example operation, S210a', for operation S210a of <FIG> of generating a bitstream within the EHT-SIG field. As shown in <FIG>, operation S210a' may include a plurality of operations S211a through S214a. <FIG> will now be described with reference to <FIG>.

In operation S211a, a bit string may be generated to represent the values of a plurality of content fields. For example, the access point <NUM> may generate a bit string representing the values of the common field and the user field of the EHT-SIG field.

In operation S212a, a determination as to whether padding is desirable may be made. According to some embodiments, the access point <NUM> may determine whether padding is desirable, based on a length of the bit string generated in operation S211a and a length of the OFDM symbol. Here, "length of the ODFM symbol" refers to a number of bits represented by the OFDM symbol (the number of bits "corresponding to the OFDM symbol"). For example, the bit string may be represented by a single OFDM symbol or by a sequence of OFDM symbols. When the number of bits of the bit string generated in operation S211a does not correspond to an integer multiple of the number of bits corresponding to the OFDM symbol, the access point <NUM> may determine that padding is desirable. For example, when one EHT-SIG OFDM symbol corresponds to <NUM> bits and the length of the bit string is <NUM> bits, <NUM> padding bits may be needed (<NUM>=<NUM>*<NUM>-<NUM>). As shown in <FIG>, when it is determined that padding is desirable, operation S213a may be subsequently performed, and, when it is determined that padding is unnecessary, operation S213a may not be performed.

When it is determined that padding is desirable, a number of padding bits may be determined (where the number is an integer that is zero when no padding bits are desired), and at least one padding bit equaling the number of padding bits may be generated (S213a). For example, the access point <NUM> may generate at least one padding bit to be added to the bit string generated in operation S211a, so that the number of bits of the bit string corresponds to an integer multiple of the number of bits corresponding to the OFDM symbol. According to some embodiments, the at least one padding bit may be referred to as a padding field.

In operation S214a, a bitstream may be generated, and the bitstream may include at least one padding bit generated as desired. For example, when it is determined in operation S212a that padding is unnecessary, the access point <NUM> may generate the bit string generated in operation S211a as the bitstream. On the other hand, when it is determined in operation S212a that padding is desired, the access point <NUM> may generate a bitstream including the bit string generated in operation S211a and the at least one padding bit generated in operation S213a. Accordingly, the number of bits of the bitstream may correspond to an integer multiple of the number of bits corresponding to the OFDM symbol.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment. In detail, the process flow diagram of <FIG> illustrates examples of operation S200 and operation S500 of <FIG>. As described above with reference to <FIG>, in operation S200b of <FIG>, an EHT-SIG field may be generated, and, in operation S500b of <FIG>, an EHT-SIG field may be extracted, and second information may be identified from the EHT-SIG field. As shown in <FIG>, operation S200b may include a plurality of operations S210b, S230b, S240b, S250b, and S290b, and operation S500b may include operation S510b and operation S520b. <FIG> will now be described with reference to <FIG>, and descriptions of <FIG> that are the same as given above with reference to <FIG> will be omitted.

Referring to <FIG>, in operation S210b, an access point <NUM> generates a bitstream, and in operation S230b, the access point <NUM> generates an encoded block from the bitstream. In the example of <FIG>, a padding bit may be omitted from the bitstream, and the encoded block may be generated from the bitstream from which the padding bit has been omitted.

In operation S240b, the access point <NUM> generates an encoded block sequence by repeating the encoded block. Differently from the example of <FIG> in which the OFDM symbol block is repeated, in the example of <FIG>, the encoded block may be repeated. In other words, in the examples of <FIG>, a pattern repeated in the EHT-SIG field of the EHT ER PPDU may be the encoded block. According to some embodiments, at least one padding bit may be added to the repeated encoded blocks as desired, and thus generation of the encoded block from the bitstream from which the padding bit has been omitted may be compensated for. An example of operation S240b will be described later with reference to <FIG>.

In operation S250b, the access point <NUM> generates a modulated block from the encoded block sequence. In operation S290b, the access point <NUM> may generate an EHT-SIG field including OFDM symbols. Differently from the example of <FIG> in which a padding bit is generated in every OFDM symbol block, in the example of <FIG>, a padding bit is added to the repeated encoded blocks. Thus, a length of the EHT-SIG field generated in <FIG> (or the number of OFDM symbols) may be equal to or less than a length of the EHT-SIG field generated in <FIG> (or the number of OFDM symbols).

In operation S510b, a station <NUM> may recover the modulated block from EHT-SIG OFDM symbols. For example, the station <NUM> may recover the modulated block from the EHT-SIG OFDM symbols included in the EHT-SIG field.

In operation S520b, the station <NUM> may identify repeated encoded blocks from the recovered modulated block. For example, the station <NUM> may generate an encoded block sequence by demodulating the modulated block recovered in operation S510b according to a predefined demodulation scheme (e.g., OFDM de-mapping), and may identify repeated encoded blocks included in the encoded block sequence. An example of operation S520b will be described later with reference to <FIG>.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment, and <FIG> is a diagram illustrating an encoded block sequence according to an embodiment. In detail, the process flow diagram of <FIG> illustrates examples of operation S240b and operation S520b of <FIG>, and <FIG> illustrates the encoded block sequence generated in operation S240b' of <FIG>. As described above with reference to <FIG>, in operation S240b' of <FIG>, the encoded block sequence may be generated by repeating an encoded block, and, in operation S520b' of <FIG>, repeated encoded blocks may be identified. As shown in <FIG>, operation S240b' may include a plurality of operations S241b through S244b, and operation S520b' may include a plurality of operations S521b through S523b. <FIG> and <FIG> will now be described with reference to <FIG>.

Referring to <FIG>, in operation S241b, the encoded block may be repeated. For example, an access point <NUM> may repeat the encoded block generated in operation S230b of <FIG> at least two times. As described above with reference to <FIG>, the encoded block may be generated from the bitstream from which the padding bit has been omitted. Referring to <FIG>, an EHT-SIG content channel may include a common field and a user specific field, and an encoded block, namely, an encoded EHT-SIG content channel, may be generated by encoding the EHT-SIG content channel according to FEC. As shown in <FIG>, padding may be omitted from the encoded EHT-SIG content channel, and the encoded block (or an ER encoded block) may be repeated.

Returning to <FIG>, in operation S242b, a determination as to whether padding is desirable may be made. According to some embodiments, the access point <NUM> may determine whether padding is desirable, based on a length of the repeated encoded blocks generated in operation S241b and a length of the OFDM symbol. For example, when the total number of bits of the repeated encoded blocks generated in operation S241b does not correspond to an integer multiple of the number of bits corresponding to the OFDM symbol, the access point <NUM> may determine that padding is desirable. As shown in <FIG>, when it is determined that padding is desirable, operation S243b may be subsequently performed, and, when it is determined that padding is unnecessary, operation S243b may not be performed.

When it is determined that padding is desirable, the access point <NUM> may generate at least one padding bit, in operation S243b. For example, the access point <NUM> may generate at least one bit, namely, at least one padding bit, to be added to the repeated encoded blocks generated in operation S241b, so that the total number of bits of the repeated encoded blocks corresponds to an integer multiple of the number of bits corresponding to the OFDM symbol.

In operation S244b, the access point <NUM> may generate the encoded block sequence, and the encoded block sequence may include the at least one padding bit generated as desirable. For example, when it is determined in operation S242b that padding is unnecessary, the access point <NUM> may generate the repeated encoded blocks generated in operation S241b as the encoded block sequence. On the other hand, when it is determined in operation S242b that padding is desirable, the access point <NUM> may generate an encoded block sequence including the repeated encoded blocks generated in operation S241b and the at least one padding bit generated in operation S243b. Accordingly, as shown in <FIG>, the encoded block sequence may be generated. According to some embodiments, when the encoded block is encoded according to BCC, the access point <NUM> may apply a BBC interleaver to bits to which a padding bit has been selectively added, and may generate an encoded block sequence to which the BBC interleaver has been applied.

In operation S521b, a station <NUM> may generate an encoded block sequence. For example, the station <NUM> may generate the encoded block sequence by demodulating a modulated block according to a predefined modulation scheme.

In operation S522b, the station <NUM> may determine whether padding exists. As described above, when the total number of bits of the repeated encoded blocks does not correspond to an integer multiple of the number of bits corresponding to the OFDM symbol, the station <NUM> may determine that padding exists in the encoded block sequence. As shown in <FIG>, when padding exists in the encoded block sequence, operation S523b may be performed, and, when no padding exists in the encoded block sequence, operation S523b may not be performed.

In operation S523b, the station <NUM> may ignore at least one padding bit in the encoded block sequence. For example, the station <NUM> may ignore at least one padding bit in the encoded block sequence, and may identify the repeated encoded blocks from a portion of the encoded block sequence from which the at least one padding bit has been omitted.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment, and <FIG> is a diagram illustrating an encoded block sequence according to an embodiment. In detail, the process flow diagram of <FIG> illustrates examples of operation S230b of <FIG> and operation S500 of <FIG>, and <FIG> illustrates the encoded block sequence generated in operation S240b' of <FIG>. As described above with reference to <FIG>, in operation S230b' of <FIG>, an encoded block may be generated. As described above with reference to <FIG>, in operation S500b' of <FIG>, an EHT-SIG field may be extracted, and second information may be identified from the EHT-SIG field. As shown in <FIG>, operation S230b' may include a plurality of operations S231b through S234b, and operation S500b' may include a plurality of operations S530b, S540b, and S550b.

Referring to <FIG>, in operation S231b, an access point <NUM> may encode a bitstream. For example, the access point <NUM> may encode the bitstream according to channel coding such as BCC or LDPC. Referring to <FIG>, an EHT-SIG content channel may include a common field and a user specific field, and an encoded EHT-SIG content channel may be generated by encoding the EHT-SIG content channel according to FEC. As shown in <FIG>, the EHT-SIG content channel (i.e., a bitstream) and the encoded EHT-SIG content channel may include no padding bits.

In operation S232b, the access point <NUM> may determine whether padding is desirable. According to some embodiments, the access point <NUM> may determine whether padding is desirable, based on a length of the bitstream encoded in operation S231b and a length of a modulated symbol. For example, when the number of bits of the encoded bitstream is not an integer multiple of the number of bits that a constellation point according to a modulation scheme has, the access point <NUM> may determine that padding is desirable. For example, when <NUM>-quadrature amplitude modulation (<NUM>-QAM) is used as the modulation scheme, one constellation point may have four bits, and, when the encoded bitstream is composed of <NUM> bits, three padding bits may be required. As shown in <FIG>, when it is determined that padding is desirable, operation S233b may be subsequently performed, and, when it is determined that padding is unnecessary, operation S233b may not be performed.

When it is determined that padding is desirable, the access point <NUM> may generate at least one padding bit, in operation S233b. For example, the access point <NUM> may generate at least one bit, namely, at least one padding bit, to be added to the encoded bitstream generated in operation S231b, so that the number of bits of the encoded bitstream corresponds to an integer multiple of the number of bits corresponding to the modulated symbol.

In operation S234b, the access point <NUM> may generate an encoded block, and the encoded block may include the at least one padding bit generated as desired. For example, when it is determined in operation S232b that padding is unnecessary, the access point <NUM> may generate the encoded bitstream generated in operation S231b as the encoded block, and the encoded block may be repeated. On the other hand, when it is determined in operation S232b that padding is desirable, the access point <NUM> may generate an encoded block sequence including the encoded bitstream generated in operation S231b and the at least one padding bit generated in operation S233b. Accordingly, as shown in <FIG>, an encoded EHT-SIG content channel and an encoded block (or an ER encoded block) including a padding bit may be generated. As shown in <FIG>, the encoded block may be repeated, a padding bit may be added to the repeated encoded blocks as desired, and the encoded block sequence may be generated.

In operation S530b, a station <NUM> may determine whether padding exists. For example, the station <NUM> may identify the repeated encoded blocks from the encoded block sequence, and may determine whether padding exists in the identified repeated encoded blocks. When the number of bits of the encoded bitstream is not an integer multiple of the number of bits corresponding to the modulated symbol, the station <NUM> may determine that padding exists in the encoded block. As shown in <FIG>, when padding exists in the encoded block, operation S540b may be performed, and, when no padding exists in the encoded block, operation S540b may not be performed.

In operation S540b, the station <NUM> may ignore at least one padding bit in the encoded block. For example, the station <NUM> may ignore at least one padding bit in the encoded block, and may identify the encoded bits (or the encoded bitstream) from a portion of the encoded block from which the at least one padding bit has been omitted.

In operation S550b, the station <NUM> may perform decoding. For example, the station <NUM> may decode the encoded bits (or the encoded bitstream) according to channel coding such as BCC or LPPC, and thus decoded bits (or a bitstream) may be generated.

<FIG> is a diagram of a U-SIG field according to an embodiment. In detail, <FIG> illustrates a U-SIG field included in the EHT ER PPDU. Descriptions of fields within <FIG> that are the same as given above with reference to <FIG> will be omitted.

Referring to <FIG>, the U-SIG field includes U-SIG-<NUM>, U-SIG-<NUM>-R, U-SIG-<NUM>, and U-SIG-<NUM>-R. The U-SIG-<NUM> and the U-SIG-<NUM>-R may include version-independent fields such as a <NUM>-bit physical version identifier field, a <NUM>-bit bandwidth field, a <NUM>-bit UL/DL field, a <NUM>-bit BSS color field, a <NUM>-bit TXOP field, and a k-bit pattern repetition number field (#) (where k is an integer greater than <NUM>). Compared with the U-SIG-<NUM> and the U-SIG-<NUM>-R of <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R of <FIG> may further include the k-bit pattern repetition number field (#). U-SIG-<NUM> and U-SIG-<NUM>-R, which are version-dependent fields, may each include a <NUM>-bit PPDU version and compression mode field, a <NUM>-bit CRC field, and a <NUM>-bit tail field.

The pattern repetition number field ("#") indicates the number of repetitions of a pattern in the EHT-SIG field or the total number of instances of the pattern within the EHT-SIG field (i.e., the number of repetitions plus one). According to some embodiments, the pattern repetition number field (#) indicates the number of repetitions of an OFDM symbol block in the EHT-SIG field, as described above with reference to <FIG>. Accordingly, the pattern repetition number field (#) included in the U-SIG-<NUM>, which is a field indicating the number of EHT-OFDM symbol blocks, may be defined as in [Table <NUM>] below.

According to some embodiments, the pattern repetition number field (#) indicates the number of repetitions of an encoded block in the EHT-SIG field, as described above with reference to <FIG>. Accordingly, the pattern repetition number field (#) included in the U-SIG-<NUM>, which is a field indicating the number of ER encoded blocks, may be defined as in [Table <NUM>] below.

An AP generates the U-SIG field including the pattern repetition number field (#) indicating the number of repetitions of a pattern (for example, an OFDM symbol block or an encoded block) or a total number of instances of the pattern within the EHT-SIG content channel, and a station may extract the pattern repetition number field (#) from the U-SIG field. The station may identify the number of repetitions of a pattern (for example, an OFDM symbol block or an encoded block), based on the value of the pattern repetition number field (#). The station may identify the repeated pattern (for example, an OFDM symbol block or an encoded block), based on the identified repetition number, and may improve a decoding success rate by combining the repeated patterns with each other.

<FIG> is a process flow diagram illustrating a method for extended range transmission, according to an embodiment. In detail, the process flow diagram of <FIG> illustrates a method of indicating a pattern repetition number in extended range transmission. According to some embodiments, operation S100" of <FIG> may be an example of operation S100 of <FIG>, and operation S400" of <FIG> may be an example of operation S400 of <FIG>. As shown in <FIG>, operation S100" may include operation S101 and operation S102, and operation S400" may include operation S401 and operation S402.

Referring to <FIG>, in operation S101, an access point <NUM> may set a mode field, based on a transmission mode. As described above with reference to <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R may include a PPDU type and compression mode field, and the access point <NUM> may set the PPDU type and compression mode field according to a transmission mode with reference to the table of <FIG>.

In operation S102, the access point <NUM> may determine a pattern repetition number, based on the transmission mode. According to some embodiments, the pattern repetition number in the EHT-SIG field of the EHT ER PPDU may depend on the transmission mode. For example, as described above with reference to <FIG>, two types of EHT-SIG content channels may be repeated in multi-user OFDMA transmission, single-user OFDMA transmission, and multi-user non-OFDMA transmission, and, as described above with reference to <FIG>, a common EHT-SIG content channel may be repeated in a single-user non-OFDMA transmission or sounding NDP. Accordingly, when the access point <NUM> sets the number of repetitions of a pattern to be n in transmission to a single user or a sounding NDP, the access point <NUM> may set the number of repetitions of a pattern to be 2n in transmission to multiple users (where n is an integer greater than <NUM>). Accordingly, the number of repetitions of a pattern in the EHT-SIG field may be determined according to the transmission mode, and the PPDU type and compression mode field may implicitly indicate the number of repetitions of a pattern.

In operation S401, a station <NUM> may identify the transmission mode, based on the value of a mode field. As described above with reference to <FIG>, the U-SIG-<NUM> and the U-SIG-<NUM>-R may include a PPDU type and compression mode field, and the access point <NUM> may identify the transmission mode, based on the value of the PPDU type and compression mode field with reference to the table of <FIG>.

In operation S402, the station <NUM> may identify a pattern repetition number, based on the transmission mode. As described above, the pattern repetition number in the EHT-SIG field may depend on the transmission mode, and the station <NUM> may identify a pattern repetition number corresponding to the transmission mode identified in operation S401.

<FIG> is a block diagram of examples of an apparatus for wireless communication according to an embodiment. In detail, <FIG> illustrates an Internet of Things (IoT) network system that includes a home gadget <NUM>, home appliances <NUM>, an entertainment device <NUM>, and an access point <NUM>.

According to some embodiments, apparatuses for wireless communication of <FIG> may support extended range transmission, as described above with reference to the drawings. Accordingly, apparatuses for wireless communication may transmit or receive a preamble including extended signal fields. An extended signal field may include repeated patterns, and an apparatus that has received the extended signal field may extract information through combination of the patterns. According to some embodiments, the pattern repeated in the signal field may be a symbol block including OFDM symbols and/or an encoded block. The number of repetitions of the pattern may be explicitly or implicitly indicated through a field included in the signal field. Accordingly, extended range transmission may be possible in a WLAN system, and coverage of the WLAN system may be extended.

Claim 1:
A wireless communication method for extended range transmission, performed by a first apparatus (<NUM>), the wireless communication method comprising:
generating a first signal field, U-SIG, having a fixed length;
generating a second signal field, EHT-SIG, having a variable length; and
transmitting a physical layer protocol data unit, PPDU, including the first signal field and the second signal field to a second apparatus (<NUM>),
wherein said generating the second signal field comprises:
generating a bitstream;
generating an encoded block by encoding the bitstream;
generating a modulated block by modulating the encoded block;
generating, from the modulated block, an orthogonal frequency-division multiplexing, OFDM, symbol block including at least one OFDM symbol; and
arranging the OFDM symbol block and one or more repetitions of the OFDM symbol block within the second signal field;
wherein the first signal field, U-SIG, includes a number of OFDM symbol blocks field indicating the number of the one or more repetitions of the OFDM symbol block or a total number of the OFDM symbol blocks in the second signal field, EHT-SIG; and
wherein said generating the first signal field, U-SIG, comprises:
generating first and second OFDM symbols modulated from first encoded bits according to different modulation schemes, respectively;
generating third and fourth OFDM symbols modulated from second encoded bits according to a common modulation scheme; and
generating the first signal field including the first through fourth OFDM symbols,
wherein the number of OFDM symbol blocks field is included in the first encoded bits.