WO2019235861A1 - Method and apparatus for identifying packet in wlan system - Google Patents

Abstract

An example according to the present disclosure relates to a technique for identifying a WLAN packet. For example, when a PPDU includes a legacy signal field, a field that is subsequent to the legacy signal field may be used to identify the type of the PPDU. The legacy signal field and the subsequent field may be modulated by a binary phase shift key (BPSK), and the field subsequent to the legacy signal field may not be repeated as it is. Specifically, the field subsequent to the legacy signal field may be generated on the basis of a sequence obtained by modifying, by a preset technique, a bit sequence applied to the legacy signal field.

Description

Method and apparatus for identifying packet in WLAN system

The present disclosure relates to a technique for transmitting and receiving data in a wireless communication, and more particularly, to a method and apparatus for configuring and receiving a packet of type identifiable in a wireless LAN system.

Wireless local area networks (WLANs) have been improved in many ways. For example, the IEEE 802.11ax standard proposed an improved communication environment using orthogonal frequency division multiple access (OFDMA) and DL MU downlink multi-user multiple input (MIMO) techniques.

The present specification improves the existing IEEE 802.11ax standard or proposes technical features that can be utilized in a new communication standard. The new communication standard may be an Extreme High Throughput (ETH) specification that is recently discussed. The EHT specification may use a newly proposed increased bandwidth, an improved PPDU structure, an improved sequence, a hybrid automatic repeat request (HARQ) technique, and the like.

Meanwhile, the IEEE standard defines PPDUs (Physical Protocol Data Units) of various types or formats. The transmitting and receiving STA used an auto-detection rule to identify the type / format of the PPDU transmitting and receiving.

As the new WLAN specification is discussed, a method and apparatus for identifying a new type of packet are needed. Since backward compatibility should be supported in a WLAN system, a new packet type should be easily distinguished from a conventional packet. The present specification proposes a method / apparatus for constructing a new type of packet and a method / apparatus for determining whether a received packet is a new type of packet.

One example according to the present disclosure relates to a method and / or apparatus for a wireless local area network (WLAN) system.

For example, the receiving device may receive a physical protocol data unit (PPDU).

The PPDU may include a legacy signal field, a control signal field subsequent to the legacy signal field, and a data field.

The legacy signal field and the control signal field may be modulated with a binary phase shift key (BPSK).

The control signal field may include a first control signal field, a second control signal field, and a third control signal field consecutive to each other.

The legacy signal field may be generated based on legacy signal bits.

The first control signal field may be generated based on the legacy signal bit and the control signal generation sequence. That is, the legacy signal field may not be repeated as it is in the first control signal field.

The receiving device may determine whether the PPDU is an Extreme High Throughput (ETH) PPDU based on the first control signal field.

An example according to the present specification may easily configure a newly defined packet in a WLAN system and easily identify / detect a newly defined packet. Through an example of the present specification, a newly defined packet and a conventional packet can coexist efficiently.

1 is a conceptual diagram illustrating a structure of a WLAN.

2 is a diagram illustrating a general link setup process.

3 is a diagram illustrating an example of a PPDU used in the IEEE standard.

4 is a diagram illustrating an arrangement of resource units (RUs) used on a 20 MHz band.

5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.

6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.

7 is a diagram illustrating another example of the HE-PPDU.

8 is a diagram for explaining an example of a frame structure used in an IEEE 802.11 system.

9 shows examples of various types of PPDUs.

10 is a diagram that distinguishes between BPSK and QBPSK.

11 is an example of an EHT PPDU that can be applied herein.

12 shows a first example of an EHT PPDU to which an example of the present specification is applied.

13 shows a second example of an EHT PPDU to which an example of the present specification is applied.

14 shows a third example of an EHT PPDU to which an example of the present specification is applied.

15 shows a fourth example of an EHT PPDU to which an example of the present specification is applied.

16 shows a fifth example of an EHT PPDU to which an example of the present specification is applied.

17 is a diagram illustrating a transmission operation to which an example of the present specification is applied.

18 is a diagram illustrating a reception operation to which an example of the present specification is applied.

19 illustrates a transmitting STA or a receiving STA to which an example of the present specification is applied.

20 shows another example of a detailed block diagram of a transceiver.

As used herein, the slash (/) or comma (comma) may mean "and / or". For example, “A / B” means “A and / or B,” and therefore may mean “only A”, “only B” or “A and B”. In addition, technical features that are separately described in one drawing may be implemented separately or may be simultaneously implemented.

In addition, parentheses used herein may mean “for example”. Specifically, when displayed as "control information (EHT-Signal)", "EHT-Signal" may be proposed as an example of "control information". In addition, even when displayed as “control information (ie, EHT-signal)”, “EHT-signal” may be proposed as an example of “control information”.

The following example of the present specification can be applied to various wireless communication systems. For example, the following example of the present specification may be applied to a wireless local area network (WLAN) system. For example, the present specification may be applied to the IEEE 802.11a / g / n / ac standard or the IEEE 802.11ax standard. In addition, the present specification may be applied to the newly proposed EHT standard or the IEEE 802.11be standard.

Hereinafter, the technical features of the WLAN system to which the present specification may be applied to describe the technical features of the present specification will be described.

1 is a conceptual diagram illustrating a structure of a WLAN.

1 shows the structure of the infrastructure basic service set (BSS) of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to the top of FIG. 1, the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area. The BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.

The BSS may include at least one STA, APs 125 and 130 for providing a distribution service, and a distribution system (DS) 110 for connecting a plurality of APs.

The distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set. The ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110. APs included in one ESS 140 may have the same service set identification (SSID).

The portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In the BSS as shown in the upper part of FIG. 1, a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130. A network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

1 is a conceptual diagram illustrating an IBSS.

Referring to the bottom of FIG. 1, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).

A STA is any functional medium that includes medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium. May be used to mean both an AP and a non-AP STA (Non-AP Station).

The STA may include a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit ( It may also be called various names such as a mobile subscriber unit or simply a user.

2 is a diagram illustrating a general link setup process.

In the illustrated step S210, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access the network, it must find a network that can participate. The STA must identify a compatible network before joining the wireless network. A network identification process existing in a specific area is called scanning. There are two types of scanning methods, active scanning and passive scanning.

2 exemplarily illustrates a network discovery operation including an active scanning process. In active scanning, the STA performing scanning transmits a probe request frame and waits for a response to discover which AP exists in the vicinity while moving channels. The responder transmits a probe response frame to the STA that transmits the probe request frame in response to the probe request frame. Here, the responder may be an STA that last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits a beacon frame, so the AP becomes a responder. In the IBSS, since the STAs in the IBSS rotate and transmit a beacon frame, the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 stores the BSS-related information included in the received probe response frame and stores the next channel (eg, number 2). Channel) to perform scanning (i.e., probe request / response transmission and reception on channel 2) in the same manner.

Although not shown in the example of FIG. 2, the scanning operation may be performed by a passive scanning method. An STA that performs scanning based on passive scanning may wait for a beacon frame while moving channels. The beacon frame is one of management frames in IEEE 802.11. The beacon frame is notified of the existence of a wireless network and is periodically transmitted to allow the STA performing scanning to find the wireless network and participate in the wireless network. In the BSS, the AP periodically transmits a beacon frame, and in the IBSS, STAs in the IBSS rotate and transmit a beacon frame. When the STA that performs the scanning receives the beacon frame, the STA stores the information on the BSS included in the beacon frame and records beacon frame information in each channel while moving to another channel. Upon receiving the beacon frame, the STA may store BSS related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.

Upon discovering the network, the STA may perform an authentication process through step S220. This authentication process may be referred to as a first authentication process in order to clearly distinguish it from the security setup operation of step S240 described later. The authentication process of S220 may include a step in which the STA transmits an authentication request frame to the AP, and in response thereto, the AP transmits an authentication response frame to the STA. An authentication frame used for authentication request / response corresponds to a management frame.

The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network, and a finite cyclic group. Group) and the like.

The STA may send an authentication request frame to the AP. The AP may determine whether to allow authentication for the corresponding STA based on the information included in the received authentication request frame. The AP may provide a result of the authentication process to the STA through an authentication response frame.

The successfully authenticated STA may perform a connection process based on step S230. The association process includes a process in which the STA transmits an association request frame to the AP, and in response thereto, the AP transmits an association response frame to the STA. For example, the connection request frame may include information related to various capabilities, beacon listening interval, service set identifier (SSID), supported rates, supported channels, RSN, and mobility domain. Information about supported operating classes, TIM Broadcast Indication Map Broadcast request, interworking service capability, and the like. For example, the connection response frame may include information related to various capabilities, status codes, association IDs (AIDs), support rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicators (RCPI), and Received Signal to Noise Information, such as an indicator, a mobility domain, a timeout interval (association comeback time), an overlapping BSS scan parameter, a TIM broadcast response, and a QoS map.

Thereafter, in step S240, the STA may perform a security setup process. The security setup process of step S240 may include, for example, performing a private key setup through 4-way handshaking through an EAPOL (Extensible Authentication Protocol over LAN) frame. .

3 is a diagram illustrating an example of a PPDU used in the IEEE standard.

As shown, various types of PHY protocol data units (PPDUs) have been used in the IEEE a / g / n / ac standard. Specifically, the LTF and STF fields include a training signal, the SIG-A and SIG-B include control information for a receiving station, and the data field includes user data corresponding to a PSDU (MAC PDU / Aggregated MAC PDU). Included.

3 also includes an example of the HE PPDU of the IEEE 802.11ax standard. The HE PPDU according to FIG. 3 is an example of a PPDU for multiple users. The HE-SIG-B may be included only for the multi-user, and the HE-SIG-B may be omitted in the PPDU for the single user.

As shown, a HE-PPDU for a multiple user (MU) includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), High efficiency-signal A (HE-SIG-A), high efficiency-signal-B (HE-SIG-B), high efficiency-short training field (HE-STF), high efficiency-long training field (HE-LTF) It may include a data field (or MAC payload) and a PE (Packet Extension) field. Each field may be transmitted during the time period shown (ie, 4 or 8 ms, etc.).

Hereinafter, a resource unit (RU) used in a PPDU will be described. The resource unit may include a plurality of subcarriers (or tones). The resource unit may be used when transmitting signals to a plurality of STAs based on the OFDMA technique. In addition, a resource unit may be defined even when transmitting a signal to one STA. Resource units may be used for STFs, LTFs, data fields and the like.

4 is a diagram illustrating an arrangement of resource units (RUs) used on a 20 MHz band.

As shown in FIG. 4, resource units (RUs) corresponding to different numbers of tones (ie, subcarriers) may be used to configure some fields of the HE-PPDU. For example, resources may be allocated in units of RUs shown for HE-STF, HE-LTF, and data fields.

As shown at the top of FIG. 4, 26-units (ie, units corresponding to 26 tones) may be arranged. Six tones may be used as the guard band in the leftmost band of the 20 MHz band, and five tones may be used as the guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones are inserted into the center band, that is, the DC band, and 26-units corresponding to each of the 13 tones may exist to the left and right of the DC band. In addition, other bands may be allocated 26-unit, 52-unit, 106-unit. Each unit can be assigned for a receiving station, i. E. A user.

On the other hand, the RU arrangement of FIG. 4 is utilized not only for the situation for a plurality of users (MU), but also for the situation for a single user (SU), in which case one 242-unit is shown as shown at the bottom of FIG. It is possible to use and in this case three DC tones can be inserted.

In the example of FIG. 4, various sizes of RUs have been proposed, that is, 26-RU, 52-RU, 106-RU, 242-RU, and the like. Since the specific sizes of these RUs can be expanded or increased, the present embodiment Is not limited to the specific size of each RU (ie, the number of corresponding tones).

5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.

Just as RUs of various sizes are used in the example of FIG. 4, the example of FIG. 5 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like. In addition, five DC tones can be inserted at the center frequency, 12 tones are used as the guard band in the leftmost band of the 40 MHz band, and 11 tones are in the rightmost band of the 40 MHz band. This guard band can be used.

Also, as shown, the 484-RU may be used when used for a single user. Meanwhile, the specific number of RUs may be changed as in the example of FIG. 4.

6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.

Just as RUs of various sizes are used in the example of FIGS. 4 and 5, the example of FIG. 6 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, and the like. have. In addition, seven DC tones can be inserted in the center frequency, 12 tones are used as the guard band in the leftmost band of the 80 MHz band, and 11 tones in the rightmost band of the 80 MHz band. This guard band can be used. Also available is a 26-RU with 13 tones each located to the left and right of the DC band.

Also, as shown, when used for a single user, a 996-RU may be used, in which case five DC tones may be inserted.

Meanwhile, the specific number of RUs may be changed as in the example of FIGS. 4 and 5.

7 is a diagram illustrating another example of the HE-PPDU.

The technical features of the HE-PPDU illustrated in FIG. 7 may be applied to the EHT-PPDU to be newly proposed. For example, the technical feature applied to the HE-SIG may be applied to the EHT-SIG, and the technical feature applied to the HE-STF / LTF may be applied to the EHT-SFT / LTF.

The illustrated L-STF 700 may include a short training orthogonal frequency division multiplexing symbol. The L-STF 700 may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.

The L-LTF 710 may include a long training orthogonal frequency division multiplexing symbol. The L-LTF 710 may be used for fine frequency / time synchronization and channel prediction.

The L-SIG 720 may be used to transmit control information. The L-SIG 720 may include information about a data rate and a data length. In addition, the L-SIG 720 may be repeatedly transmitted. That is, the L-SIG 720 may be configured in a repeating format (for example, may be referred to as an R-LSIG).

The HE-SIG-A 730 may include control information common to the receiving station.

Specifically, the HE-SIG-A 730 may include 1) a DL / UL indicator, 2) a BSS color field which is an identifier of a BSS, 3) a field indicating a remaining time of a current TXOP interval, 4) 20, Bandwidth field indicating whether 40, 80, 160, 80 + 80 MHz, 5) field indicating the MCS scheme applied to HE-SIG-B, 6) dual subcarrier modulation for HE-SIG-B field indicating whether it is modulated by dual subcarrier modulation), 7) field indicating the number of symbols used for HE-SIG-B, and 8) indicating whether HE-SIG-B is generated over the entire band. Field, 9) field indicating the number of symbols of the HE-LTF, 10) field indicating the length and CP length of the HE-LTF, 11) field indicating whether additional OFDM symbols exist for LDPC coding, 12) A field indicating control information about a packet extension (PE), and 13) a field indicating information on a CRC field of the HE-SIG-A. have. Specific fields of the HE-SIG-A may be added or omitted. In addition, some fields may be added or omitted in other environments where the HE-SIG-A is not a multi-user (MU) environment.

The HE-SIG-B 740 may be included only when it is a PPDU for a multi-user (MU) as described above. Basically, the HE-SIG-A 750 or the HE-SIG-B 760 may include resource allocation information (or virtual resource allocation information) for at least one receiving STA.

The HE-STF 750 may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment.

The HE-LTF 760 may be used to estimate a channel in a MIMO environment or an OFDMA environment.

The size of the FFT / IFFT applied to the field after the HE-STF 750 and the HE-STF 750 may be different from the size of the FFT / IFFT applied to the field before the HE-STF 750. For example, the size of the FFT / IFFT applied to the fields after the HE-STF 750 and the HE-STF 750 may be four times larger than the size of the IFFT applied to the field before the HE-STF 750. .

For example, at least one of L-STF 700, L-LTF 710, L-SIG 720, HE-SIG-A 730, HE-SIG-B 740 on the PPDU of FIG. When a field of s is called a first field, at least one of the data field 770, the HE-STF 750, and the HE-LTF 760 may be referred to as a second field. The first field may include a field related to a legacy system, and the second field may include a field related to a HE system. In this case, the FFT (fast Fourier transform) size / inverse fast Fourier transform (IFFT) size is N times the FFT / IFFT size used in the conventional WLAN system (N is a natural number, for example, N = 1, 2, 4) can be defined. That is, an FFT / IFFT of N (= 4) times size may be applied to the second field of the HE PPDU compared to the first field of the HE PPDU. For example, 256 FFT / IFFT is applied for a bandwidth of 20 MHz, 512 FFT / IFFT is applied for a bandwidth of 40 MHz, 1024 FFT / IFFT is applied for a bandwidth of 80 MHz, and 2048 FFT for a bandwidth of 160 MHz continuous or discontinuous 160 MHz. / IFFT can be applied.

In other words, the subcarrier spacing / subcarrier spacing is 1 / N times the size of the subcarrier space used in the conventional WLAN system (N is a natural number, for example, 78.125 kHz when N = 4). Can be. That is, a subcarrier spacing of 312.5 kHz, which is a conventional subcarrier spacing, may be applied to a first field of the HE PPDU, and a subcarrier space of 78.125 kHz may be applied to a second field of the HE PPDU.

Alternatively, the IDFT / DFT period applied to each symbol of the first field may be expressed as N (= 4) times shorter than the IDFT / DFT period applied to each data symbol of the second field. . That is, the IDFT / DFT length applied to each symbol of the first field of the HE PPDU is 3.2 μs, and the IDFT / DFT length applied to each symbol of the second field of the HE PPDU is 3.2 μs * 4 (= 12.8 μs Can be expressed as The length of an OFDM symbol may be a value obtained by adding a length of a guard interval (GI) to an IDFT / DFT length. The length of the GI can be various values such as 0.4 μs, 0.8 μs, 1.6 μs, 2.4 μs, 3.2 μs.

For convenience of description, although the frequency band used by the first field and the frequency band used by the second field are represented in FIG. 7, they may not exactly coincide with each other. For example, the main band of the first field (L-STF, L-LTF, L-SIG, HE-SIG-A, HE-SIG-B) corresponding to the first frequency band is the second field (HE-STF). , HE-LTF, Data) is the same as the main band, but in each frequency band, the interface may be inconsistent. 4 to 6, since a plurality of null subcarriers, DC tones, guard tones, etc. are inserted in the process of arranging the RU, it may be difficult to accurately match the interface.

The user, that is, the receiving station, may receive the HE-SIG-A 730 and may be instructed to receive the downlink PPDU based on the HE-SIG-A 730. In this case, the STA may perform decoding based on the changed FFT size from the field after the HE-STF 750 and the HE-STF 750. On the contrary, if the STA is not instructed to receive the downlink PPDU based on the HE-SIG-A 730, the STA may stop decoding and configure a network allocation vector (NAV). The cyclic prefix (CP) of the HE-STF 750 may have a larger size than the CP of another field, and during this CP period, the STA may perform decoding on the downlink PPDU by changing the FFT size.

Hereinafter, in the present embodiment, data (or frame) transmitted from the AP to the STA is called downlink data (or downlink frame), and data (or frame) transmitted from the STA to the AP is called uplink data (or uplink frame). Can be expressed in terms. In addition, the transmission from the AP to the STA may be expressed in terms of downlink transmission, and the transmission from the STA to the AP may be expressed in terms of uplink transmission.

8 is a diagram for explaining an example of a frame structure used in an IEEE 802.11 system. The STF, LTF, and SIG fields shown in FIG. 8 may be the same as or correspond to the (HT / VHT / EHT) -STF, LTF, and SIG fields shown in FIG. 3 or 7. In addition, the DATA field illustrated in FIG. 8 may be the same as or correspond to the DATA field illustrated in FIGS. 3/7.

The data field may include a SERVICE field, a physical layer service data unit (PSDU), a PPDU TAIL bit, and may also include a padding bit if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to an MPDU (MAC Protocol Data Unit) defined in the MAC layer and may include data generated / used in an upper layer. The PPDU TAIL bit can be used to return the encoder to zero. The padding bit may be used to adjust the length of the data field in a predetermined unit.

The MPDU is defined according to various MAC frame formats, and the basic MAC frame is composed of a MAC header, a frame body, and a frame check sequence (FCS). The MAC frame may be composed of MPDUs and may be transmitted / received through the PSDU of the data portion of the PPDU frame format.

The MAC header includes a frame control field, a duration / ID field, an address field, and the like. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to a time for transmitting the corresponding frame.

The duration / ID field included in the MAC header may be set to 16 bits long (e.b., B0 to B15). The content included in the period / ID field may vary depending on the frame type and subtype, whether the content is transmitted during the CFP (contention free period), the QoS capability of the transmitting STA, and the like. (i) In the control frame of which the subtype is PS-Poll, the duration / ID field may include the AID of the transmitting STA (e.g., via 14 LSB bits) and the 2 MSB bits may be set to one. (ii) In frames transmitted during CFP by a point coordinator (PC) or a non-QoS STA, the period / ID field may be set to a fixed value (e.g., 32768). (iii) In other frames transmitted by the non-QoS STA or control frames transmitted by the QoS STA, the duration / ID field may include a duration value defined for each frame type. In a data frame or management frame transmitted by the QoS STA, the duration / ID field may include a duration value defined for each frame type. For example, when B15 = 0 of the duration / ID field indicates that the duration / ID field is used to indicate TXOP Duration, B0 to B14 may be used to indicate actual TXOP Duration. The actual TXOP Duration indicated by B0 to B14 may be any one of 0 to 32767, and the unit may be microseconds (μs). However, when the duration / ID field indicates a fixed TXOP Duration value (e.g., 32768), B15 = 1 and B0 to B14 = 0 may be set. In addition, when B14 = 1 and B15 = 1, the period / ID field is used to indicate an AID, and B0 to B13 indicate one AID of 1 to 2007.

The frame control field of the MAC header may include Protocol Version, Type, Subtype, To DS, From DS, More Fragment, Retry, Power Management, More Data, Protected Frame, Order subfields.

Hereinafter, an auto-detection rule used in the IEEE standard will be described. The transmission / reception STA of the WLAN system may simultaneously support PPDUs of various types / formats. In order to identify or detect the intended type / format at the receiving STA, a PPDU configured based on a preset rule should be transmitted. Such a rule may be called an auto-detection rule. An example of a preset rule is described with reference to FIGS. 12 to 16.

The PPDU may be determined in various types / formats. For example, the type / format of the PPDU may be determined based on the non-HT, HT, VHT, HE, and EHT standards.

9 shows examples of various types of PPDUs.

As shown in FIG. 9, an example of the type (ie, format) of the PPDU used in the WLAN system includes non-HT, HT, VHT, HE PPDU, and the like. Specifically, the illustrated first type PPDU 910 is a non-HT PPDU defined in the IEEE 802.11a standard and the like, and the illustrated second type PPDU 920 and the third type PPDU 930 are defined in the IEEE 802.11n standard and the like. It is HT PPDU. In addition, the illustrated fourth type PPDU 940 is a VHT PPDU defined in the IEEE 802.11ac standard and the like, and the illustrated fifth type PPDU 950 and the sixth type PPDU 960 are defined in the IEEE 802.11ax standard and the like. to be.

All types of PPDUs 910, 920, 930, 940, 950, 960 shown in FIG. 9 include L-STF and L-LTF fields. Each of the L-STF and L-LTF fields may be transmitted on two symbols (eg, OFDM symbols). That is, each of the L-STF and L-LTF fields may have a transmission time for 8 μs.

All types of PPDUs 910, 920, 930, 940, 950, and 960 shown in FIG. 9 include an L-SIG field or an HT-SIG1 field subsequent to the L-LTF field. The L-SIG field or the HT-SIG1 field shown in FIG. 9 may be transmitted through one symbol.

As shown in FIG. 9, the HT-SIG1 field of the third type PPDU 930 may be modulated based on quadrature binary phase shift keying (QBPSK) characteristics. The QBPSK constellation may be a constellation rotated by 90 degrees counterclockwise with respect to the BPSK constellation.

10 is a diagram that distinguishes between BPSK and QBPSK. As shown, the QBPSK constellation may be a constellation rotated by 90 degrees counterclockwise based on the BPSK constellation.

Since QBPSK is applied to the HT-SIG1 field of the third type PPDU 930 of FIG. 9, the receiving STA may identify that the received PPDU is the third type PPDU when QBPSK is applied to a symbol received after the L-LTF field. have. In addition, when the BPSK is applied to a symbol received after the L-LTF field, the receiving STA may identify that the received PPDU is any one of a first, second, fourth, fifth, and sixth type of PPDU.

PPDUs of the fifth and sixth types may be identified / detected by the receiving STA based on the following example. The fifth and sixth types of PPDUs include a RL-SIG (Repeated L-SIG) in which a field consecutive to the L-SIG field is repeated as it is. In addition, the fifth and sixth types of PPDUs include three symbols after the L-SIG field, and the three symbols consist of RL-SIG, HE-SIGA1, and HE-SIGA2. The receiving STA repeats the L-SIG as it is in a symbol consecutive to the L-SIG field, and selects three symbols (ie, at least one of RL-SIG, HE-SIGA1, and HE-SIGA2) that exist after the L-SIG field. Using this, it is possible to identify / detect that the received PPDU is a PPDU of the fifth and sixth type.

On the other hand, in the fifth type of PPDU 950, the property applied to the third symbol after the L-SIG field is BPSK, and the sixth type of PPDU 960 is applied to the third symbol after the L-SIG field. This is QBPSK. Accordingly, the receiving STA may distinguish the fifth and sixth type of PPDU from each other based on whether the constellation applied to the third symbol after the L-SIG field is BPSK or QPBSK.

In addition, in the fourth type of PPDU, a field consecutive to the L-SIG field does not repeat the L-SIG as it is, BPSK is applied to the first symbol consecutive to the L-SIG, and the second consecutive to the first symbol. QBPSK is applied to a symbol. Accordingly, the receiving STA may identify the fourth type of PPDU based on whether the L-SIG field is repeated and / or whether QBPSK is applied to the second symbol.

In addition, since the QBPSK is applied to two symbols consecutive to the L-SIG in the second type of PPDU, the receiving STA may identify / detect the second type of PPDU from another type of PPDU. In addition, as described above, since all of the second to sixth type of PPDUs have distinguishable characteristics, PPDUs not identified or detected as the second to sixth type of PPDUs may be identified / detected to the first type of PPDUs. have.

The specific order of the above-described identification / detection method may be changed. That is, when uniquely configuring the number / shape of symbols after the L-LTF as shown in FIG. 9, the receiving STA may accurately identify the type of the received PPDU through various methods.

Hereinafter, the present specification proposes an example for identifying / detecting a new type of PPDU. The new type of PPDU proposed herein may be an EHT PPDU. In addition, the new type of PPDU proposed herein may be a PPDU according to the IEEE 802.11be standard. An EHT PPDU and / or a PPDU according to the IEEE 802.11be standard may support the technical features described below.

Wide bandwidth (eg, up to 320 MHz) can be supported for EHT PPDUs (or PPDUs conforming to the IEEE 802.11be standard) so that higher data rates can be supported than existing standards. In addition, EHT PPDUs can be transmitted / received. The STA (that is, the EHT STA) may support a maximum of 16 streams, and the EHT STA may transmit / receive the EHT PPDU on various frequency channels / bands, that is, the EHT STA may support multi-band operation. The EHT PPDU may be transmitted and received in various bands, for example, in the 2.4 GHz / 5 GHz / 6 GHz band.

The EHT PPDU can also be used with various conventional PPDUs shown in FIG. 9. In order for the EHT PPDU to be mixed with the conventional type PPDU, the receiving STA must be able to easily identify / detect the type of the EHT PPDU. The following example proposes an example of a PPDU that can easily identify / detect the EHT PPDU.

11 is an example of an EHT PPDU that can be applied herein. For convenience of description, the PPDU of FIG. 11 includes a plurality of fields (eg, RL-SIG, EHT-SIGA, DATA, etc.), but some of the fields shown may be omitted, or the order of the fields may be changed. Can be.

Each field of the PPDU illustrated in FIG. 11 may be transmitted through at least one symbol (ie, OFDM symbol). The time length of an OFDM symbol can be determined in various ways, for example, an integer multiple of 4 μs. In addition, the OFDM symbol used for the PPDU of FIG. 11 may include a Guard Interval (or Short GI). All of the fields shown are applied with a common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, N = integer) or the first part (e.g., all L-Parts, all EHT-Parts / A part of the first delta_f may be applied, and a part of the remaining parts may include a second delta_f (eg, a value smaller than the first delta_f).

As shown, the Legacy Part 1110 of FIG. 11 includes at least one of a Non-HT Short Training Field (L-STF), a Non-HT Long Training Field (L-LTF), and a Non-HT Signal Field (L-SIG). It may include one. In addition, the EHT Part 1150 of FIG. 11 may include various control information for the transmitted PPDU. For example, the EHT Part 1150 may include an EHT STF (not shown), an EHT LTF (not shown), and Data 1180.

The EHT STF (not shown) may include an EHT STF signal. The EHT-STF signal may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment. The EHT LTF (not shown) may include an EHT LTF signal. The EHT-LTF signal may be used for MIMO channel estimation.

The EHT Part 1150 may include at least one control signal field 1160. In other words, a control signal field 1160 continuous to the legacy signal field 1140 may be defined in the PPDU. The control signal field 1160 may include a first control signal field, a second control signal field, and a third control signal field consecutive to each other. In the example of FIG. 11, as an example of the control signal field 1160, RL-SIG, EHT-SIGA1, and EHT-SIGA2 fields which are continuous to each other are set.

The EHT-SIGA1 and / or EHT-SIGA2 fields of FIG. 11 may include various control information. For example, the EHT-SIGA1 / EHT-SIGA2 field may include 1) a DL / UL indicator, 2) a BSS color field as an identifier of a BSS, 3) a field indicating a remaining time of a current TXOP interval, 4) 20, Bandwidth field indicating whether 40, 80, 160, 80 + 80, 320, 160 + 160, 240 MHz, 5) field indicating the MCS scheme applied to EHT-SIG-B, 6) EHT-SIG-B Field indicating whether it is modulated by dual subcarrier modulation for MCS, 7) field indicating the number of symbols used for EHT-SIG-B, 8) EHT-SIG-B is full-band 9) a field indicating whether the number of symbols of the EHT-LTF is generated, 10) a field indicating the length of the EHT-LTF and the CP length, and 11) an additional OFDM symbol for LDPC coding. A field indicating whether there exists, 12) a field indicating control information regarding a PE (packet extension), and / or 13) information about a CRC field of EHT-SIGA1 / SIGA2. Of the fields that may include at least one field.

Meanwhile, the legacy signal field 1140 of FIG. 11 may include 24 bits of control information. The 24-bit control information may be called a legacy signal bit. For example, the legacy signal field 1140 may include 4 bits of rate information, and the 12 bits of length information may include information about the length of the PSDU included in the PPDU. In addition, the legacy signal field 1140 may include 6 bits of signal tail information, 1 bit of parity bit, and 1 bit of reserve bit.

This specification proposes an example of EHT-PPDU based on the example of FIG. When the following specific example is applied, the receiving STA may easily identify / detect that the received PPDU is an EHT type PPDU (ie, EHT-PPDU).

12 shows an example of an EHT PPDU to which an example of the present specification is applied.

The PPDU of FIG. 12 may include a legacy signal field, a control signal field continuous to the legacy signal field, and a data field. In addition, the control signal field may include a first control signal field, a second control signal field, and a third control signal field which are continuous to each other. In the example of FIG. 12, the legacy signal field may be referred to as the illustrated L-SIG 1230, and the first control signal field, the second control signal field, and the third control signal field consecutive to each other may be referred to as RL-SIG ( 1240), EHT-SIGA1 1250, and EHT-SIGA2 1260. In other words, examples of FIG. 12 include L-STF 1210, L-LTF 1220, L-SIG 1230, RL-SIG 1240, EHT-SIGA1 1250, EHT-SIGA2 1260. And data fields.

In the following example (FIGS. 12 to 16), the EHT-SIGA field (ie, EHT-SIGA1, EHT-SIGA2, EHT-SIGA3, etc.) may include various control information described in FIG. 11 of the EHT PPDU. In addition, in the following example, BPSK modulation may be applied to the EHT-SIGA field.

The L-STF 1210 and L-LTF 1220 of FIG. 12 may be configured in the same manner as the conventional L-STF and L-LTF, and the L-SIG 1230 includes the aforementioned 24-bit control information. can do.

Specifically, in order to generate the L-SIG 1230 of FIG. 12, the transmitting STA performs binary convolutional code (BCC) encoding on a 24-bit control information at 1/2 code rate, and modulates BPSK on the encoded 48-bit information. Can be performed. The transmitting STA may generate the L-SIG 1230 signal by allocating the 48 generated BPSK symbols to the remaining frequency tones except for the DC tone and the pilot tone (-21, -7, +7, and +21 indexes). have. That is, each subcarrier index of the L-SIG 1230 signal may be disposed in the frequency domain at a subcarrier spacing interval of 312.5 kHz, and the L-SIG 1230 signal generated by the transmitting STA is + -26 index from +26 index. 26 may be transmitted through a frequency domain corresponding to the index. The above-described characteristics of the subcarrier spacing and the pilot tone can be equally applied to all fields (except data fields) shown in FIGS. 12 to 16.

The RL-SIG 1240 of FIG. 12 may be generated according to the following example. In detail, the transmitting STA may generate the RL-SIG 1240 signal based on the 24-bit information included in the L-SIG 1230. For example, the transmitting STA may perform binary convolutional code (BCC) coding on a 24-bit control information at 1/2 code rate and perform QPSK modulation on the encoded 48-bit information. That is, the transmitting STA may generate 24 QPSK symbols for the RL-SIG 1240.

When QPSK modulation is applied to the RL-SIG 1240, the data rate may be twice as high as that of the L-SIG 1230 to which the BPSK is applied. The transmitting STA 1) applies dual carrier modulation (DCM) to the RL-SIG 1240 or 2) the same data signal in the frequency domain to apply the same data rate to the L-SIG 1230 and the RL-SIG 1240. Can be repeated.

12 shows an RL-SIG 1240 with DCM applied. Specifically, the RL-SIG may include a first QPSK symbol (eg, any one of 24 QPSK symbols) on the subcarrier K, and may include a complex conjugate of the first QPSK symbol on the subcarrier K + N_SD. Alternatively, a value obtained by multiplying (-1) ^k by the first QPSK symbol may be included on the subcarrier K + N_SD. More specifically, 24 QPSK symbols are allocated to the remaining 24 subcarrier indexes except for the pilot index in the region from the subcarrier index -26 to the subcarrier index -1 (or in the region from 1 to 26). A complex conjugate of 24 QPSK symbols may be included in the remaining 24 subcarrier indices except for the pilot index in the region from index 1 to subcarrier index 26 (or in the region from -26 to -1). Alternatively, the subcarrier index may include a value obtained by multiplying 24 QPSK symbols by (-1) ^k .

According to another example, the RL-SIG includes a first QPSK symbol on subcarrier index k and indexes on subcarrier index k + 1 (if subcarrier index k + 1 corresponds to a pilot or DC index). It is also possible to include the same first QPSK symbol (where incremented by one). Also, the second QPSK symbol may be included on subcarrier indexes k + 2 and k + 3 (increased by 1 for DC / pilot indexes), and on subcarrier indexes k + 4 and k + 5 (DC / In the case of the pilot index, the same third QPSK symbol may be included).

The EHT PPDU may be received through a 5 GHz band, and the 5 GHz band region may also be used for transmission of the HT PPDU, VHT PPDU, and HE PPDU. Accordingly, the configuration of the EHT-PPDU is preferably determined to be distinguished from other PPDUs. In the example of FIG. 12, since QPSK is applied to the RL-SIG 1240 consecutive to the L-SIG 1230, an error that the HT / VHT / HE STA recognizes the EHT PPDU as another type of PPDU can be minimized. .

Specifically, as described with reference to FIG. 9, the HT STA may measure constellations of two symbols consecutive to the L-SIG, and may determine that the received PPDU is an HT type when the constellations of the two symbols are both QBPSK. . When the BPSK and QPSK symbols are included after the L-SIG as shown in FIG. 12, the HT STA may not recognize the QBPSK when examining the constellation of two consecutive symbols of the L-SIG. Through this, an error occurring in the HT STA can be reduced.

In addition, as described with reference to FIG. 9, the VHT STA may measure constellations of two symbols consecutive to the L-SIG, and may determine that the received PPDU is a VHT type when the constellations of the two symbols are BPSK and QBPSK. . When the QPSK scheme is applied to the RL-SIG as shown in FIG. 12, constellation mapping between the VHT PPDU and the EHT PPDU is determined differently. This can reduce errors occurring in the VHT STA.

In addition, as described with reference to FIG. 9, the HE STA determines whether the L-SIG is repeated in a symbol subsequent to the L-SIG. In the example of FIG. 12, since QPSK is applied to a symbol consecutive to the L-SIG, the HE STA determines that the L-SIG of the PPDU of FIG. 12 is not repeated. Accordingly, an error occurring in the HE STA can be reduced.

Upon receiving the example of FIG. 12, the STA may determine whether the received PPDU is an EHT PPDU depending on whether QPSK is applied to the RL-SIG 1240 subsequent to the L-SIG 1230. In addition, the receiving STA may perform demodulation / decoding on the RL-SIG 1240 after determining whether the received PPDU is an EHT PPDU. When the receiving STA performs demodulation / decoding on the RL-SIG 1240, the 24-bit control information included in the RL-SIG 1240 is the same as the 24-bit control information included in the L-SIG 1230. Therefore, the receiving STA may increase the accuracy of demodulation / decoding by combining the L-SIG 1230 and the RL-SIG 1240.

13 shows an example of an EHT PPDU to which an example of the present specification is applied.

The PPDU of FIG. 13 may include a legacy signal field, a control signal field continuous to the legacy signal field, and a data field. In addition, the control signal field may include a first control signal field, a second control signal field, and a third control signal field which are continuous to each other. In the example of FIG. 13, the legacy signal field may be referred to as the illustrated L-SIG 1330, and the first control signal field, the second control signal field, and the third control signal field consecutive to each other may be Rep-Sym ( 1340, EHT-SIGA1 1350, and EHT-SIGA2 1360. In other words, examples of FIG. 13 include L-STF 1310, L-LTF 1320, L-SIG 1330, Rep-Sym 1340, EHT-SIGA1 1350, and EHT-SIGA2 1360. And data fields.

The L-STF 1310 and L-LTF 1320 of FIG. 13 may be configured in the same manner as the conventional L-STF and L-LTF, and the L-SIG 1330 is the L-SIG 1230 of FIG. 12. It may be configured in the same manner as.

Rep-Sym 1340 of FIG. 13 may be used to indicate that the type of PPDU of FIG. 13 is an EHT PPDU. That is, when the Rep-Sym 1340 of FIG. 13 is received, the receiving STA may determine / detect that the type of the PPDU including the Rep-Sym 1340 is an EHT PPDU.

Rep-Sym 1340 of FIG. 13 may be configured as follows.

The Rep-Sym 1340 may include an M bit sequence or common information of M bits. For example, common information included in the Rep-Sym 1340 may be related to at least one of BW, mode, format type, and BSS color. For example, the information about the bandwidth (BW) may be indication information (eg, 1-bit identifier) as to whether the BW of the PPDU exceeds a threshold (eg, 160 MHz). That is, information about the BW of the PPDU is included in the Rep-Sym 1340 and the EHT-SIGA 1350 and / or 1360, and the Rep-Sym 1340 includes only information on whether the BW exceeds a threshold. The remaining information for accurately identifying / detecting the BW of the PPDU may be included in the EHT-SIGA. For example, the information about the mode may include various information related to the operation of the transmitting / receiving STA. That is, the number of streams used, information about MU-MIMO / SU-MIMO, information about UL-MU operation, information about Power Save, information about LTF / STF sequence, information about TXOP, and / or EDCA It may contain information about. In addition, the information about the format type may include information about various types of the PPDU. For example, it may be related to whether the EHT-PPDU is SU-PPDU, MU-PPDU, PPDU for UL-MU communication, PPDU for Extended Range communication, or the like. The information about the BSS Color may be all or part of the BSS Color ID.

M can be set variously, for example, it can be 24 bits or 12 bits. For Rep-Sym 1340, binary convolutional code (BCC) encoding may be performed at a 1/2 code rate. The transmitting STA may apply BPSK modulation to the coded bits. Or, the transmitting STA may perform BPSK modulation on M bits without encoding.

The transmitting STA may map BPSK symbols to time / frequency resources in various ways to configure the Rep-Sym 1340. For example, the transmitting STA may configure a repetitive signal in the time domain. In detail, the transmitting STA may map a plurality of BPSK symbols only to an even subcarrier index or an odd subcarrier index. In this case, if IDFT / IFFT is applied to the corresponding BPSK symbol, the same signal may be repeated for one symbol period (for example, 4 μs). When such a repetitive signal is included in the EHT PPDU, the receiving STA can easily detect / determine the type of the receiving PPDU. As a further example, the transmitting STA may allocate P (e.g., 24) BPSK symbols in a particular first frequency domain and assign the same P BPSK symbols in a second frequency domain that is continuous in the first frequency domain. Can be. That is, as shown in FIG. 13, the transmitting STA allocates the symbols of “d_BPSK” to “d_BPSK (p)” to the first frequency domain and again assigns the same symbols of “d_BPSK” to “d_BPSK (p)” to the second frequency domain. Can be assigned to the frequency domain.

In the example of FIG. 13, since the Rep-Sym 1340 is repeated in the time and / or frequency domain, an error that the HT / VHT / HE STA recognizes the EHT PPDU as another type of PPDU can be minimized.

That is, since the BPSK symbols are continuous in the example of FIG. 13, the example of FIG. 13 may be easily distinguished from the HT PPDU. In addition, since BPSK + QBPSK is not used in the example of FIG. 13, the example of FIG. 13 may be easily distinguished from the VHT PPDU. In addition, in the example of FIG. 13, since the L-SIG is not repeated as it is after the L-SIG, the example of FIG. 13 is easily distinguished from the HE-PPDU.

14 shows an example of an EHT PPDU to which an example of the present specification is applied.

The PPDU of FIG. 14 may include a legacy signal field, a control signal field continuous to the legacy signal field, and a data field. In addition, the control signal field may include a first control signal field, a second control signal field, and a third control signal field which are continuous to each other. In the example of FIG. 14, the legacy signal field may be referred to as the illustrated L-SIG 1430, and the first control signal field, the second control signal field, and the third control signal field that are continuous with each other may be referred to as RL-SIG ( 1440), EHT-SIGA1 1450, and EHT-SIGA2 1460. In other words, examples of FIG. 14 include L-STF 1410, L-LTF 1420, L-SIG 1430, RL-SIG 1440, EHT-SIGA1 1450, and EHT-SIGA2 1460. And data fields.

The L-STF 1410 and L-LTF 1420 of FIG. 14 may be configured in the same manner as the conventional L-STF and L-LTF, and the L-SIG 1430 is the L-SIG 1230 of FIG. 12. It may be configured in the same manner as.

The RL-SIG 1440 of FIG. 14 may be used to indicate that the type of the PPDU of FIG. 14 is an EHT PPDU. That is, when the RL-SIG 1440 of FIG. 14 is received, the receiving STA may determine / detect that the type of the PPDU including the RL-SIG 1440 is an EHT PPDU.

The RL-SIG 1440 of FIG. 14 may be configured as follows.

The RL-SIG 1440 of FIG. 14 may be generated based on 24 bit information (ie, legacy signal bits) and a control signal generation sequence included in the SIG 1430. Alternatively, the RL-SIG 1440 of FIG. 14 may be generated based on complementary bits of 24-bit information (that is, legacy signal bits) included in the L-SIG 1430.

A detailed method of generating the RL-SIG 1440 of FIG. 14 may be as follows.

The transmitting STA may configure N-bit (eg, 24-bit) information for the RL-SIG 1440 based on the 24-bit information included in the L-SIG 1430. The N bit information for the RL-SIG 1440 may be configured in various ways. For example, the N bit information for the RL-SIG 1440 may be a complementary bit of 24-bit information (ie, legacy signal bits) included in the L-SIG 1430. Alternatively, the N bit information for the RL-SIG 1440 may be generated based on the 24-bit information included in the L-SIG 1430 (ie, legacy signal bits) and the control signal generation sequence. Specifically, the N bit information for the RL-SIG 1440 is generated based on an XOR (eXclusive OR) operation between the 24-bit information included in the L-SIG 1430 (ie, legacy signal bits) and the control signal generation sequence. Can be. The control signal generation sequence may have any length. For example, the control signal generation sequence may be a 1 bit sequence or a 24-bit sequence.

If the above-described example is embodied through a formula as follows.

As a first example, the N bit information for the RL-SIG 1440 may be a complementary bit of 24-bit information (ie, legacy signal bits) included in the L-SIG 1430. For example, 24 data bits of the L-SIG 1430 may be {1 1 0 1 1 1 0 1 0 ... 1 1 0}. In this case, 24-bit information for the RL-SIG 1440 may be {0 0 1 0 0 0 1 0 1 ... 0 0 1}. That is, the above technique may maximize the Euclidean distance between the L-SIG 1430 and the RL-SIG 1440.

In a second example, N bit information for the RL-SIG 1440 may be generated based on an XOR operation between 24 data bits of the L-SIG 1430 and a control signal generation sequence. That is, the transmitting STA may generate 24-bit information for the RL-SIG 1440 through an XOR operation between 24 data bits and 1 bit (ie, 1 or 0) of the L-SIG 1430. In addition, the transmitting STA may generate 24-bit information for the RL-SIG 1440 through an XOR operation between 24 data bits of the L-SIG 1430 and a preset 24-bit sequence (or a preset 12-bit sequence). . An example of the 12-bit sequence described above may be equal to {1 0 0 0 0 1 0 1 0 1 1 1}. In addition, the preset 24-bit sequence may be generated based on the 12-bit sequence. For example, the preset 24-bit sequence may be generated by repeating the 12-bit sequence. Alternatively, the preset 24-bit sequence may include a sequence for reducing PAPR.

The transmitting STA performs BCC (Binary Convolutional Code) coding at 1/2 code rate on N bits (eg, 24 bits) information for the RL-SIG 1440, and performs BPSK modulation on the encoded 2N bits information. can do. The transmitting STA may configure the RL-SIG 1440 by allocating the generated 2N BPSK symbols to the remaining frequency tones except for the DC tone and the pilot tone (-21, -7, +7, and +21 indexes). .

The method described above may be variously changed. For example, the transmitting STA performs binary convolutional code (BCC) encoding on the 24-bit information included in the L-SIG 1430 (that is, legacy signal bits) at a half code rate, and encodes the encoded 48-bit information. BPSK modulation may be performed. Thereafter, the transmitting STA multiplies the -1 signal for 48 BPSK modulation symbols and allocates the multiplied signal to the remaining frequency tones except the DC tone and the pilot tone (-21, -7, +7, and +21 indexes). RL-SIG 1440 may be configured.

In the example of FIG. 14, since the L-SIG 1430 and all subsequent SIG symbols are modulated by BPSK, the receiving STA can easily distinguish the example of FIG. 14 from the HT PPDU or the VHT PPDU. In addition, due to the technical features applied to the RL-SIG 1440 of FIG. 14, the receiving STA may easily distinguish the example of FIG. 14 from the HE-PPDU.

15 shows an example of an EHT PPDU to which an example of the present specification is applied.

The PPDU of FIG. 15 may include a legacy signal field, a control signal field continuous to the legacy signal field, and a data field. In addition, the control signal field may include a first control signal field, a second control signal field, and a third control signal field which are continuous to each other. In the example of FIG. 15, the legacy signal field may be referred to as the illustrated L-SIG 1530, and the first control signal field, the second control signal field, and the third control signal field contiguous with each other are EHT-SIGA1 ( 1540, EHT-SIGA2 1550, and EHT-SIGA3 1560. In other words, examples of FIG. 15 include L-STF 1510, L-LTF 1520, L-SIG 1530, EHT-SIGA1 1540, EHT-SIGA2 1550, and EHT-SIGA3 1560. And data fields. Unlike the example of FIG. 15, the number of EHT-SIGAs may be added.

The L-STF 1510 and L-LTF 1520 of FIG. 15 may be configured in the same manner as the conventional L-STF and L-LTF, and the L-SIG 1530 may be configured as the L-SIG 1230 of FIG. 12. It may be configured in the same manner as.

In the example of FIG. 15, the EHT-SIGA2 1550 is configured in the same manner as the EHT-SIGA1 1540. That is, the transmitting STA may configure the EHT-SIGA2 1550 in the same manner as the EHT-SIGA1 1540 to indicate that the type of the PPDU of FIG. 15 is an EHT PPDU.

In the example of FIG. 15, since the EHT-SIGA symbol to which the BPSK is applied is repeated, reception performance may be improved. In addition, since the BPSK symbol is repeated in the example of FIG. 15, the example of FIG. 15 may be easily distinguished from the HT / VHT PPDU. In addition, since the L-SIG 1530 is not repeated in the example of FIG. 15, the example of FIG. 15 may be easily distinguished from the HE PPDU.

16 shows an example of an EHT PPDU to which an example of the present specification is applied.

The PPDU of FIG. 16 may include a legacy signal field, a control signal field continuous to the legacy signal field, and a data field. In addition, the control signal field may include a first control signal field, a second control signal field, and a third control signal field which are continuous to each other. In the example of FIG. 16, the legacy signal field may be referred to as the illustrated L-SIG 1630, and the first control signal field, the second control signal field, and the third control signal field consecutive to each other may be Signature Symbol 1640. ), EHT-SIGA1 (1650), EHT-SI2A3 (1660). In other words, examples of FIG. 16 include L-STF 1610, L-LTF 1620, L-SIG 1630, Signature Symbol 1640, EHT-SIGA1 1650, EHT-SIGA2 1660, and the like. It may include data fields.

The L-STF 1610 and L-LTF 1620 of FIG. 16 may be configured in the same manner as the conventional L-STF and L-LTF, and the L-SIG 1630 is the L-SIG 1230 of FIG. It may be configured in the same manner as.

The Signature Symbol 1640 of FIG. 16 may be used to indicate that the type of the PPDU of FIG. 16 is an EHT PPDU. That is, when the Signature Symbol 1640 of FIG. 16 is received, the receiving STA may determine / detect that the type of the PPDU including the Signature Symbol 1640 is an EHT PPDU. The BPSK modulation may be applied to the signature symbol 1640. In the example of FIG. 16, one Signature Symbol 1640 is included, but the same Signature Symbol 1640 may be repeated, and the number of repetitions may be freely set to 2, 3, or the like.

Since the BPSK symbol is repeated after the L-SIG in the example of FIG. 16, the example of FIG. 16 can be easily distinguished from the HT / VHT PPDU. In addition, since the L-SIG 1630 is not repeated in the example of FIG. 16, the example of FIG. 15 may be easily distinguished from the HE PPDU.

The Signature Symbol 1640 of FIG. 16 may be generated based on the Signature sequence. Technical characteristics for the signature sequence may be as follows.

The signature sequence may be a time sequence or a frequency sequence.

The Signature Symbol 1640 may be transmitted on various numbers of subcarriers (eg, 52 or 48). For this purpose, the Signature sequence may be defined as the following structure.

[Example 1]

Signature sequence = {s1 s2 s3 s4 s5... … S50 s51 s52}

The 52-bit sequence as described above may be divided into a left 26 bit sequence (signature sequence_left_26) and a right 26 bit sequence (signature sequence_right_26).

That is, it may be defined as follows.

[Example 2]

signature sequence_left_26 = {s1 s2... s25, s26}

signature sequence_right_26 = {s27 s28... s51 s52}

Based on the example 2, the Signature Symbol 1640 may be configured as follows.

[Example 3]

Signature symbol = {0 0 0 0 0 0 signature sequence_left_26 0 signature sequence_right_26 0 0 0 0 0}

That is, as shown in Example 3, six left guards and five right guards are inserted into the Signature Symbol 1640, and the left 26-bit sequence on the left and right sides of the DC component on the frequency band and The right 26 bit sequence may be included.

The sequence of Example 1 may be used to identify the type of PPDU. For example, the sequence of Example 1 may be used to indicate EHT PPDU type 1 and EHT PPDU type 2, in which case Example 1 is used to indicate EHT PPDU type 1, and Example 1 to indicate EHT PPDU type 2. A complementary sequence for may be included in the Signature Symbol 1640. That is, the receiving STA may identify / determine that the receiving PPDU is a first type of EHT PPDU (eg, an EHT PPDU for SU mode) when the sequence of Example 1 is received, and the receiving STA may identify the sequence of Example 1 of the sequence. When the complementary sequence is received, it may be identified / determined that the received PPDU is a second type of EHT PPDU (eg, EHT PPDU for MU mode).

The Signature Symbol 1640 may be generated based on the following 53-bit sequence and six left guards and five right guards.

[Example 4]

signature sequence_53 = {s1 s2 s3 s4 s5... … S50 s51 s52 s53}

Signature symbol = {0 0 0 0 0 0 signature sequence_ 53 0 0 0 0 0}

According to another example, the Signature Symbol 1640 may be generated based on the following 26 bit sequence, six left guards, and five right guards. That is, the Signature Symbol 1640 may be configured in such a manner that a 26-bit sequence is repeated in the frequency domain.

[Example 5]

signature_seq_26 = {s1 s2 s3 s4 s5... … s24 s25 s26}

Signature symbol = {0 0 0 0 0 0 signature_seq_26 0 signature_seq_26 0 0 0 0 0}

Signature Symbol 1640 herein can be configured in a variety of ways using a 26 bit sequence.

[Example 6]

Signature symbol = {0 0 0 0 0 0 signature_seq_26 0 (signature_seq_26) * (-1) 0 0 0 0 0}

Signature symbol = {0 0 0 0 0 0 (signature_seq_26) * (-1) 0 (signature_seq_26) 0 0 0 0 0}

Signature symbol = {0 0 0 0 0 0 (signature_seq_26) 0 (complementary sequences of signature_seq_26) 0 0 0 0 0}

The above-described example may be variously changed. The transmitting STA may assign each component of the aforementioned 26 bit sequence only to an odd subcarrier index or an even subcarrier index. In this case, since the final signal to which the IFFT / IDFT is applied is repeated in the time domain for one symbol period (for example, 4 μs), the receiving STA easily determines the type of the received PPDU using the repeated signal pattern. can do.

In addition, the above-described signature sequence may be composed of a conventional PN (Pseudo Noise) -sequence / ML (Maximum Length) sequence / orthogonal sequence. For example, when the length of the conventional sequence is odd, an even length signature sequence may be generated by adding 0 or 1 to the conventional odd sequence.

In addition, the lengths of the 26, 52, and 53 bit sequences (ie, signature sequences) may be variously changed. In addition, the signature sequence may be a set including a plurality of sequences. In this case, the hamming distance for a plurality of sequences included in one set may be greater than or equal to a threshold of hamming distance. In detail, the transmitting STA may include any one of a plurality of sequences (first, second, third sequence, etc.) included in one set. When the transmitting STA generates the Signature Symbol 1640 based on the first sequence, information indicating that the EHT PPDU is the first type (or first control information for another use) may be delivered to the receiving STA. In order to properly detect a plurality of sequences in the receiving STA, it may be preferable that a hamming distance is set to 7 or 9 or more between a plurality of sequences included in one set.

17 is a diagram illustrating a transmission operation to which an example of the present specification is applied. The example of FIG. 17 may be performed at a transmitting STA transmitting a PPDU.

In step S1710, the transmitting STA obtains information about the PPDU type. For example, when the PPDU type corresponds to the conventional type shown in FIG. 9, the transmitting STA may configure an RL-SIG field, a SIG-A field, and the like according to the conventional technique.

If the transmitting STA obtains information on the EHT PPDU type through step S1710, the transmitting STA may perform step S1720. That is, the transmitting STA may generate the first control signal field based on the example of FIGS. 12 to 16 described above. For example, the transmitting STA is the RL-SIG 1240 of FIG. 12, the Rep-Sym 1340 of FIG. 13, the RL-SIG 1440 of FIG. 14, and the EHT-SIGA1 1540 / EHT-SIGA2 of FIG. 15. 1550, or the Signature Symbol 1640 of FIG. 16 may be generated. The transmitting STA may indicate that the type of the transmitting PPDU is related to the EHT PPDU through the first control signal field configured through step S1720.

In step S1730, the transmitting STA may transmit an EHT PPDU including the first control signal field.

18 is a diagram illustrating a reception operation to which an example of the present specification is applied. The example of FIG. 18 may be performed at a receiving STA receiving a PPDU.

In step S1810 the receiving STA may receive the EHT PPDU including the first control signal field. The first control signal field includes the RL-SIG 1240 of FIG. 12, the Rep-Sym 1340 of FIG. 13, the RL-SIG 1440 of FIG. 14, and the EHT-SIGA1 1540 / EHT-SIGA2 (FIG. 15). 1550, or the Signature Symbol 1640 of FIG. 16.

In step S1820, the receiving STA may determine that the received PPDU is an EHT PPDU when the first control signal field generated according to the example of the present specification is received.

19 illustrates a transmitting STA or a receiving STA to which an example of the present specification is applied.

Referring to FIG. 19, an STA 1900 may include a processor 1910, a memory 1920, and a transceiver 1930. 19 may be applied to a non-AP STA or an AP STA. The illustrated processor, memory, and transceiver may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.

The illustrated transceiver 1930 performs transmission and reception of signals. Specifically, it is possible to transmit and receive IEEE 802.11 packets (for example, IEEE 802.11a / b / g / n / ac / ax / be, etc.).

The processor 1910 may implement the functions, processes, and / or methods proposed herein. In detail, the processor 1910 may receive a signal through the transceiver 1930, process the received signal, generate a transmission signal, and perform control for signal transmission.

Such a processor 1910 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and a data processing device. The memory 1920 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device.

The memory 1920 may store a signal (ie, a received signal) received through the transceiver, and store a signal (ie, a transmission signal) to be transmitted through the transceiver. That is, the processor 1910 may acquire the received signal through the memory 1920 and store the signal to be transmitted in the memory 1920.

20 shows another example of a detailed block diagram of a transceiver. Some or all of the blocks of FIG. 20 may be included in the processor 1910. Referring to FIG. 20, the transceiver 110 includes a transmitting part 111 and a receiving part 112. The transmission part 111 includes a discrete fourier transform (DFT) unit 1111, a subcarrier mapper 1112, an IFFT unit 1113, a CP insertion unit 1144, and a wireless transmitter 1115. The transmission part 111 may further include a modulator. Further, for example, the apparatus may further include a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown) and a layer permutator (not shown). It may be disposed before the DFT unit 1111. That is, in order to prevent an increase in peak-to-average power ratio (PAPR), the transmission part 111 first passes the information through the DFT 1111 before mapping a signal to a subcarrier. After subcarrier mapping of the signal spread (or precoded in the same sense) by the DFT unit 1111 through the subcarrier mapper 1112, the inverse fast fourier transform (IFFT) unit 1113 is again passed on the time axis. Make it a signal.

The DFT unit 1111 outputs complex-valued symbols by performing a DFT on the input symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit 1111 may be called a transform precoder. The subcarrier mapper 1112 maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1112 may be called a resource element mapper. The IFFT unit 1113 performs an IFFT on the input symbol and outputs a baseband signal for data, which is a time domain signal. The CP inserter 1114 copies a part of the rear part of the base band signal for data and inserts it in the front part of the base band signal for data. Inter-symbol interference (ISI) and inter-carrier interference (ICI) can be prevented through CP insertion to maintain orthogonality even in multipath channels.

On the other hand, the reception part 112 includes a radio receiver 1121, a CP remover 1122, an FFT unit 1123, an equalizer 1124, and the like. The wireless receiving unit 1121, the CP removing unit 1122, and the FFT unit 1123 of the receiving part 112 include a wireless transmitting unit 1115, a CP insertion unit 1114, and an IFF unit 1113 at the transmitting end 111. It performs the reverse function of). The receiving part 112 may further include a demodulator.

In addition to the illustrated block, the transceiver of FIG. 20 may include a reception window controller (not shown) for extracting a part of a received signal, and a decoding operation processor (not shown) for performing a decoding operation on a signal extracted through the reception window. ) May be included.

The technical features of the present specification described above can be applied to various applications or business models. For example, the above-described technical feature may be applied for wireless communication in a device supporting artificial intelligence (AI).

Artificial intelligence refers to the field of researching artificial intelligence or the methodology that can produce it, and machine learning refers to the field of researching methodologies that define and solve various problems in the field of artificial intelligence. do. Machine learning is defined as an algorithm that improves the performance of a task through a consistent experience with a task.

Artificial Neural Network (ANN) is a model used in machine learning, and may refer to an overall problem-solving model composed of artificial neurons (nodes) formed by combining synapses. The artificial neural network may be defined by a connection pattern between neurons of different layers, a learning process of updating model parameters, and an activation function generating an output value.

The artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and the artificial neural network may include synapses that connect neurons to neurons. In an artificial neural network, each neuron may output a function value of an active function for input signals, weights, and deflections input through a synapse.

The model parameter refers to a parameter determined through learning and includes weights of synaptic connections and deflection of neurons. In addition, the hyperparameter means a parameter to be set before learning in the machine learning algorithm, and includes a learning rate, the number of iterations, a mini batch size, and an initialization function.

The purpose of learning artificial neural networks can be seen as determining model parameters that minimize the loss function. The loss function can be used as an index for determining optimal model parameters in the learning process of artificial neural networks.

Machine learning can be categorized into supervised learning, unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of learning artificial neural networks with a given label for training data, and a label indicates a correct answer (or result value) that the artificial neural network should infer when the training data is input to the artificial neural network. Can mean. Unsupervised learning may refer to a method of training artificial neural networks in a state where a label for training data is not given. Reinforcement learning can mean a learning method that allows an agent defined in an environment to learn to choose an action or sequence of actions that maximizes cumulative reward in each state.

Machine learning, which is implemented as a deep neural network (DNN) including a plurality of hidden layers among artificial neural networks, is called deep learning (Deep Learning), which is part of machine learning. In the following, machine learning is used to mean deep learning.

In addition, the above technical features can be applied to the wireless communication of the robot.

A robot can mean a machine that automatically handles or operates a given task by its own ability. In particular, a robot having a function of recognizing the environment, judging itself, and performing an operation may be referred to as an intelligent robot.

Robots can be classified into industrial, medical, household, military, etc. according to the purpose or field of use. The robot may include a driving unit including an actuator or a motor to perform various physical operations such as moving a robot joint. In addition, the movable robot includes a wheel, a brake, a propeller, and the like in the driving unit, and can travel on the ground or fly in the air through the driving unit.

In addition, the above-described technical feature may be applied to an apparatus supporting extended reality.

Extended reality collectively refers to Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). VR technology provides real world objects or backgrounds only in CG images, AR technology provides virtual CG images on real objects images, and MR technology mixes and combines virtual objects in the real world. Graphic technology.

MR technology is similar to AR technology in that it shows both real and virtual objects. However, in AR technology, the virtual object is used as a complementary form to the real object, whereas in the MR technology, the virtual object and the real object are used in the same nature.

XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phone, tablet PC, laptop, desktop, TV, digital signage, etc. It can be called.

Claims (13)

1. In a wireless local area network (WLAN) system,

   Receive a Physical Protocol Data Unit (PPDU),

   The PPDU comprises a legacy signal field, a control signal field subsequent to the legacy signal field, and a data field,

   The legacy signal field and the control signal field is modulated with a binary phase shift key (BPSK),

   The control signal field includes a first control signal field, a second control signal field, and a third control signal field consecutive to each other,

   The legacy signal field is generated based on the legacy signal bits,

   Generating the first control signal field based on the legacy signal bit and control signal generation sequence; And

   Determining whether the PPDU is an Extreme High Throughput (EHT) PPDU based on the first control signal field

   How to include.
2. The method of claim 1,

   The control signal generation sequence has a length of M bits,

   M is any positive number,

   The first control signal field is generated based on an eXclusive OR (XOR) operation between the legacy signal bit and a control signal generation sequence.

   Way.
3. The method of claim 2,

   The control signal generation sequence is a 1 bit sequence and is set to {1} or {0}.

   Way.
4. The method of claim 1,

   The second control signal field includes information for decoding the third control signal field,

   The third control signal field includes information for decoding the data field.

   Way.
5. The method of claim 1,

   Determining whether the PPDU is an EHT PPDU,

   Determining whether the first control signal field is generated based on the legacy signal bit and the control signal generation sequence

   Way.
6. In a wireless local area network (WLAN) system,

   Create a legacy signal field, a control signal field contiguous to the legacy signal field, and a data field,

   The legacy signal field and the control signal field is modulated with a binary phase shift key (BPSK),

   The control signal field includes a first control signal field, a second control signal field, and a third control signal field consecutive to each other,

   The legacy signal field is generated based on the legacy signal bits,

   Generating the first control signal field based on the legacy signal bit and control signal generation sequence; And

   Transmitting an Extreme High Throughput (EHT) Physical Protocol Data Unit (PPDU) including the legacy signal field, the control signal field, and the data field.

   Containing

   Way.
7. The method of claim 6,

   The control signal generation sequence has a length of M bits,

   M is any positive number,

   The first control signal field is generated based on an eXclusive OR (XOR) operation between the legacy signal bit and a control signal generation sequence.

   Way.
8. The method of claim 7, wherein

   The control signal generation sequence is a 1 bit sequence and is set to {1} or {0}.

   Way.
9. The method of claim 6,

   The second control signal field includes information for decoding the third control signal field,

   The third control signal field includes information for decoding the data field.

   Way.
10. In a station (STA) of a wireless local area network (WLAN) system,

    A memory for storing a received signal; And

    Includes a processor (processor) connected to the memory,

    The processor is

    Obtain a Physical Protocol Data Unit (PPDU) from the memory,

    The PPDU includes a legacy signal field, a control signal field subsequent to the legacy signal field, and a data field,

    The legacy signal field and the control signal field is modulated with a binary phase shift key (BPSK),

    The control signal field includes a first control signal field, a second control signal field, and a third control signal field consecutive to each other,

    The legacy signal field is generated based on the legacy signal bits,

    The first control signal field is generated based on the legacy signal bit and the control signal generation sequence,

    Determining whether the PPDU is an Extreme High Throughput (EHT) PPDU based on the first control signal field

    Device.
11. The method of claim 10,

    The control signal generation sequence has a length of M bits,

    M is any positive number,

    The first control signal field is generated based on an eXclusive OR (XOR) operation between the legacy signal bit and a control signal generation sequence.

    Way.
12. The method of claim 11,

    The control signal generation sequence is a 1 bit sequence and is set to {1} or {0}.

    Way.
13. The method of claim 10,

    The second control signal field includes information for decoding the third control signal field,

    The third control signal field includes information for decoding the data field.

    Way.

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