WO2020159030A1 - Method and apparatus for performing power saving in wireless lan system - Google Patents

Abstract

A method and an apparatus for performing power saving in a wireless LAN system are presented. Particularly, an AP transmits first data to a first STA through a first band for a first duration. The AP transmits second data to a second STA through a second band while the first data is transmitted. The AP performs power saving for the first STA in the second band for the first duration. The first band and the second band are combined as multiple bands. The first STA switches to a doze state in the second band for the first duration.

Description

Method and apparatus for performing power saving in a wireless LAN system

The present specification relates to a technique for performing power saving in a wireless LAN system, and more particularly, to a method and apparatus for performing power saving by applying a multi-band and TDD technique in a wireless LAN system.

Discussions are being conducted for the next generation wireless local area network (WLAN). In the next generation WLAN, 1) enhancement of the Institute of electronic and electronics engineers (IEEE) 802.11 physical (PHY) layer and medium access control (MAC) layer in the 2.4GHz and 5GHz bands, 2) spectrum efficiency and area throughput The goal is to improve performance in real indoor and outdoor environments, such as increasing through put, 3) in environments where interference sources exist, in dense heterogeneous network environments, and in environments with high user loads.

The environment mainly considered in the next generation WLAN is a dense environment with many access points (APs) and stations (STAs), and improvements in spectrum efficiency and area throughput are discussed in this dense environment. In addition, the next-generation WLAN is interested in improving the actual performance in the outdoor environment, which was not much considered in the existing WLAN as well as the indoor environment.

Specifically, in the next generation WLAN, there is a great interest in scenarios such as wireless office, smart home, stadium, hotspot, building/apartment, and AP based on the scenario. Discussions are being made on improving system performance in a dense environment with many and STAs.

In addition, in the next generation WLAN, rather than improving the performance of a single link in one basic service set (BSS), there will be active discussions about improving system performance in the overlapping basic service set (OBSS) environment, improving outdoor environment performance, and cellular offloading. Is expected. The directionality of the next-generation WLAN means that the next-generation WLAN gradually has a technology range similar to mobile communication. Considering the situation where mobile communication and WLAN technology are being discussed together in the small cell and direct-to-direct (D2D) communication areas, the technological and business convergence of next-generation WLAN and mobile communication is expected to become more active.

This specification proposes a method and apparatus for performing power saving in a wireless LAN system.

An example of the present specification proposes a method for performing power saving.

This embodiment can be performed in a network environment in which a next generation wireless LAN system is supported. The next-generation wireless LAN system is an improved wireless LAN system that can satisfy backward compatibility with the 802.11ax system. The next generation WLAN system may correspond to an Extreme High Throughput (EHT) WLAN system or an 802.11be WLAN system.

This embodiment proposes a method for performing efficient power saving by using multi-band aggregation and TDD in a next-generation wireless LAN system such as EHT.

This embodiment is performed in the AP, and the first and second STAs of this embodiment may correspond to STAs supporting an Extremely High Throughput (EHT) wireless LAN system. The AP and the first and second STAs may support multiple bands (or multiple links).

The AP (Access Point) transmits the first data to the first STA (Station) during the first duration through the first band.

The AP transmits the second data to the second STA through the second band while the first data is transmitted.

The AP performs power saving in the second band for the first STA during the first duration.

The first band and the second band are aggregated with each other in a multi-band. The first band includes a first primary channel, and the second band includes a second primary channel.

If the multiple bands are combined into only two bands, the first band may be a 2.4 GHz or 5 GHz band, and the second band may be a 6 GHz band. If the third band of the multi-band is further combined, the first band may be the 2.4 GHz band, the second band may be the 5 GHz band, and the third band may be the 6 GHz band. However, the configuration of the above-described band is only an example, and the wireless LAN system may support various numbers of bands and channels.

The multi-band supports DL transmission and UL transmission at the same time. This is called FDU (Flexible DL/UL) transmission. FDU transmission is a transmission technique that can increase TSS/Rx average throughput by simultaneously enabling Tx/Rx transmission in multiple bands.

The first STA is switched to a doze state in the second band during the first duration. That is, the first STA receives the first data (or first PPDU) in the first band, but the second STA receives the second data (or second PPDU) in the second band for the same time. Therefore, the first STA may perform power saving for the second band. During the first duration, since the second STA is receiving the second data in the second band, the first STA cannot use the channel of the second band during the corresponding time. The first STA may switch to a doze state for the second band during the first duration.

Further, the AP may transmit third data to the first STA during the second duration through the first band. When the channel of the second band is BUSY during the second duration, the AP may perform the power saving in the second band for the first STA. In this case, the first STA may be switched to the doze state in the second band during the second duration. That is, since the channel of the second band is BUSY during the second duration, the first STA cannot use the channel of the second band during the corresponding time. Accordingly, the first STA may switch to the doze state for the second band during the first duration.

In addition, the AP may transmit the fourth data to the first STA during the third duration through the second band. When there is no data to be transmitted in the first band during the third duration, the AP may perform the power saving in the first band for the first STA. The first STA may switch to a doze state in the first band during the third duration. That is, since there is no data to be transmitted in the first band during the third duration, the first STA does not use the channel of the first band during the corresponding time. Accordingly, the first STA may switch to the doze state for the first band during the third duration.

Also, the fourth data may include information that there is no data to be transmitted in the first band during the third duration. Accordingly, the first STA can know that there is no data transmission in the first band until the transmission of the fourth data is transmitted in the second band, until the transmission of the fourth data ends (the Power saving).

Each of the multi-bands can also be applied to the TDD technique. Accordingly, accordingly, the first and second data are transmitted during the first duration, the third data is transmitted during the second duration, and the fourth data is transmitted during the third duration. However, the first to third durations do not overlap in the time domain. That is, the first to third durations may be distinguished from each other in different sections in a time domain by applying a TDD technique to the multiple bands. Accordingly, the first duration, the second duration, and the third duration may be time intervals sequentially transmitted.

The power saving includes power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state It can be power saving.

The first and third data may include first information on power saving in the second band, and the fourth data may include second information on power saving in the first band.

The first information may be included in a signal field or MAC frame of the first and third data, and the second information may be included in a signal field or MAC frame of the fourth data.

The fourth data may include third information about whether there is data to be transmitted in the first band. The third information may be set as one bit. For example, if there is data to be transmitted in the first band (specific band), the bit may be set to 1, and if there is no data to be transmitted in the first band, the bit may be set to 0.

The first band and the second band may represent channels. Accordingly, the first band may be a primary channel of a specific band, and the second band may be a secondary channel of a specific band.

In addition, the first band may be a band including a primary channel, and the second band may be a band including a secondary channel.

Hereinafter, a signaling method for multi-band aggregation will be described. In this embodiment, it has been described as receiving configuration information for multiple bands, and signaling may be performed by using the FST configuration method.

The transmitting device and the receiving device described below may be the aforementioned AP or the first and second STAs. The transmitting device may transmit a multi-band setting request frame to the receiving device. The transmitting device may receive a multi-band setting response frame from the receiving device.

The transmitting device may transmit a multi-band Ack request frame to the receiving device. The transmitting device may receive a multi-band Ack response frame from the receiving device.

The transmitting device may include a first Station Management Entity (SME), a first MAC Layer Management Entity (MLME), and a second MLME. The receiving device may include a second SME, a third MLME, and a fourth MLME.

The first MLME and the third MLME are entities supporting the first band, and the second MLME and the fourth MLME may be entities supporting the second band.

The multi-band setup request frame and the multi-band setup response frame may be transmitted and received between the first MLME and the third MLME. The multi-band Ack request frame and the multi-band Ack response frame may be transmitted and received between the second MLME and the fourth MLME.

The first and second SME may generate primitives including multi-band parameters. The multi-band parameter may include a channel number designated in the multi-band, an operating class, and a band ID (identifier). The primitive may be delivered to the first to fourth MLME.

When the multi-band method borrows the FST setting method, it includes four states, and is composed of rules for a method of moving from one state to the next. The four states are Initial, Setup Completed, Transition Done and Transition Confirmed.

In the Initial state, the transmitting device and the receiving device communicate in an old band/channel. At this time, when the FST setup request frame and the FST setup response frame are transmitted and received between the transmitting apparatus and the receiving apparatus, the system moves to a Setup Complete state, and the transmitting apparatus and the receiving apparatus are ready to change the currently operating band/channel(s). do. The FST session may be delivered in whole or in part to other bands/channels.

When the value of the LLT included in the FST setup request frame is 0, it moves from the Setup Complete state to the Transition Done state, and allows the transmitting device and the receiving device to operate in different bands/channels.

Both the transmitting and receiving devices must successfully communicate in a new band/channel to reach the Transition Confirmed state. At this time, when the FST Ack request frame and the FST Ack response frame are transmitted and received between the transmitting device and the receiving device, the device moves to a Transition Confirmed state, and the transmitting device and the receiving device form a complete connection in a new band/channel.

According to the embodiment proposed in the present specification, efficient power saving can be performed by applying a TDD technique to multiple bands, and transmission efficiency for multiple channels can be increased.

1 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

2 is a diagram showing an example of a PPDU used in the IEEE standard.

3 is a diagram showing an example of an HE PPDU.

4 is a diagram showing the arrangement of a resource unit (RU) used on a 20MHz band.

5 is a view showing the arrangement of a resource unit (RU) used on the 40MHz band.

6 is a view showing the arrangement of a resource unit (RU) used on the 80MHz band.

7 is a view showing another example of the HE-PPDU.

8 is a block diagram showing an example of HE-SIG-B according to the present embodiment.

9 shows an example of a trigger frame.

10 shows an example of a subfield included in a per user information field.

11 is a block diagram showing an example of a control field and a data field constructed according to the present embodiment.

12 is a view showing an example of the HE TB PPDU.

13 shows multiple channels allocated in the 5 GHz band.

14 shows four states of the FST setting protocol.

15 shows the procedure of the FST establishment protocol.

16 shows an example of multi-band aggregation using the 2.4 GHz band and the 5 GHz band.

17 shows an example in which a primary channel exists in each band (or RF) when performing multi-band aggregation.

18 shows an example of applying the BC decrement rule of the B-2) method in the case of aggregation of the 2.4 GHz, 5 GHz, and 6 GHz bands.

19 is an example of applying an FDD scheme to a wireless LAN system.

20 is an example in which DL or UL transmission is performed in a TDD scheme in a multi-band environment.

21 is an example of operating an independent data queue for each channel band in a multi-band environment.

22 is an example in which a plurality of channel bands share and operate an integrated data queue in a multi-band environment.

23 shows an example in which power saving is performed in multiple bands.

24 is a flowchart illustrating a procedure for an AP to perform power saving according to this embodiment.

25 is a flowchart illustrating a procedure for a STA to perform power saving according to this embodiment.

26 is a diagram for describing an apparatus for implementing the method as described above.

27 shows a more detailed wireless device implementing an embodiment of the present invention.

1 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

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

Referring to the top of FIG. 1, the wireless LAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The BSS (100, 105) is a set of APs and STAs such as an access point (AP) 125 and an STA1 (Station 100-1) that can successfully communicate with each other by synchronizing, and is not a concept indicating a specific area. The BSS 105 may include one or more combineable STAs 105-1 and 105-2 in one AP 130.

The BSS may include at least one STA, APs 125 and 130 providing distributed services, and a distributed system (DS, 110) connecting multiple APs.

The distributed system 110 may connect multiple BSSs 100 and 105 to implement an extended service set (ESS) 140. The ESS 140 may be used as a term indicating one network in which one or more 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 that performs a connection between a wireless LAN network (IEEE 802.11) and another network (eg, 802.X).

In the BSS such as the top of FIG. 1, a network between APs 125 and 130 and a network between APs 125 and 130 and STAs 100-1, 105-1, and 105-2 may be implemented. However, it may be possible to perform communication by establishing a network even between STAs without APs 125 and 130. A network performing communication by setting 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 showing an IBSS.

1, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not include an AP, there is no centralized management entity that performs management functions centrally. That is, STAs 150-1, 150-2, 150-3, 155-4, and 155-5 in the IBSS are managed in a distributed manner. In IBSS, all STAs (150-1, 150-2, 150-3, 155-4, 155-5) may be made of mobile STAs, and access to a distributed system is not allowed, so a self-contained network network).

STA is an arbitrary functional medium including a medium access control (MAC) and a physical layer interface to a wireless medium in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Can be used to mean both an AP and a non-AP STA (Non-AP Station).

The STA includes a mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), user equipment (UE), mobile station (MS), and mobile subscriber unit ( Mobile Subscriber Unit) or simply a user (user).

Meanwhile, the term user may be used in various meanings, and may also be used to mean an STA participating in uplink MU MIMO and/or uplink OFDMA transmission in wireless LAN communication, for example. It is not limited thereto.

2 is a diagram showing an example of a PPDU used in the IEEE standard.

As illustrated, various types of PHY protocol data units (PPDUs) have been used in standards such as IEEE a/g/n/ac. Specifically, the LTF and STF fields included training signals, and SIG-A and SIG-B included control information for the receiving station, and data fields included user data corresponding to PSDU.

This embodiment proposes an improved technique for the signal (or control information field) used for the data field of the PPDU. The signal proposed in this embodiment can be applied on a high efficiency PPDU (HE PPDU) according to the IEEE 802.11ax standard. That is, the signal to be improved in this embodiment may be HE-SIG-A and/or HE-SIG-B included in the HE PPDU. Each of HE-SIG-A and HE-SIG-B can also be marked as SIG-A, SIG-B. However, the improved signal proposed by the present embodiment is not necessarily limited to the HE-SIG-A and/or HE-SIG-B standards, and control of various names including control information in a wireless communication system for transmitting user data/ Applicable to data fields.

3 is a diagram showing an example of an HE PPDU.

The control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG. 3. The HE PPDU according to FIG. 3 is an example of a PPDU for multiple users, and HE-SIG-B is included only for multiple users, and the corresponding HE-SIG-B may be omitted in the PPDU for a single user.

As shown, HE-PPDU for multiple users (MU) is a legacy-short training field (L-STF), legacy-long training field (L-LTF), 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) , Data field (or MAC payload) and PE (Packet Extension) field. Each field may be transmitted during the illustrated time period (ie, 4 or 8 ms, etc.).

More detailed description of each field in FIG. 3 will be described later.

4 is a diagram showing the arrangement of a resource unit (RU) used on a 20MHz 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 RU shown for HE-STF, HE-LTF, and data fields.

As shown at the top of Fig. 4, 26-units (i.e., units corresponding to 26 tones) can be arranged. Six tones may be used as a guard band in the leftmost band of the 20 MHz band, and five tones may be used as a guard band in the rightmost band of the 20 MHz band. In addition, 7 DC tones are inserted into the central band, that is, the DC band, and 26-units corresponding to each of 13 tones may exist to the left and right of the DC band. In addition, 26-units, 52-units, and 106-units may be allocated to other bands. Each unit can be assigned for a receiving station, ie a user.

Meanwhile, the RU arrangement of FIG. 4 is utilized not only for a situation for multiple users (MU), but also for a situation for single users (SU), in this case, one 242-unit is shown as shown at the bottom of FIG. 4. It is possible to use and in this case 3 DC tones can be inserted.

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

5 is a view showing the arrangement of a resource unit (RU) used on the 40MHz band.

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

Also, as shown, when used for a single user, 484-RU can be used. Meanwhile, the fact that the specific number of RUs can be changed is the same as the example of FIG. 4.

6 is a view showing the arrangement of a resource unit (RU) used on the 80MHz band.

Just as RUs of various sizes are used in the examples of FIGS. 4 and 5, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, and the like in FIG. 6 may also be used. have. In addition, 7 DC tones can be inserted into the center frequency, 12 tones are used in the leftmost band of the 80 MHz band as a guard band, and 11 tones are located in the rightmost band of the 80 MHz band. It can be used as a guard band. It is also possible to use 26-RUs with 13 tones located on the left and right sides of the DC band.

Also, as shown, when used for a single user, 996-RU can be used, in which case 5 DC tones can be inserted.

Meanwhile, the fact that the specific number of RUs can be changed is the same as the example of FIGS. 4 and 5.

7 is a view showing another example of the HE-PPDU.

The illustrated block of FIG. 7 is another example of explaining the HE-PPDU block of FIG. 3 in terms of frequency.

The illustrated L-STF 700 may include a short training orthogonal frequency division multiplexing symbol (OFDM). 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 (OFDM). L-LTF 710 may be used for fine frequency/time synchronization and channel prediction.

The L-SIG 720 can be used to transmit control information. The L-SIG 720 may include information about data transmission rate and data length. Also, the L-SIG 720 may be repeatedly transmitted. That is, the L-SIG 720 may be configured in a repeating format (eg, R-LSIG).

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

Specifically, HE-SIG-A 730 includes: 1) a DL/UL indicator, 2) a BSS color field that is an identifier of the BSS, 3) a field indicating the remaining time of the current TXOP section, 4) 20, Bandwidth field indicating whether 40, 80, 160, 80+80 MHz, 5) Field indicating MCS technique applied to HE-SIG-B, 6) HE-SIG-B dual subcarrier modulation for MCS ( dual subcarrier modulation) indication field for modulating, 7) field indicating the number of symbols used for HE-SIG-B, 8) indicating whether HE-SIG-B is generated over the entire band. Field, 9) a field indicating the number of symbols of the HE-LTF, 10) a field indicating the length and CP length of the HE-LTF, 11) a field indicating whether there are additional OFDM symbols for LDPC coding, 12) Fields indicating control information on PE (Packet Extension), 13) Fields indicating information on CRC field of HE-SIG-A, and the like may be included. Specific fields of the HE-SIG-A may be added or some of them may be omitted. In addition, some fields may be added or omitted in other environments in which HE-SIG-A is not a multi-user (MU) environment.

In addition, HE-SIG-A 730 may be composed of two parts, HE-SIG-A1 and HE-SIG-A2. HE-SIG-A1 and HE-SIG-A2 included in HE-SIG-A may be defined in the following format structure (field) according to the PPDU. First, the HE-SIG-A field of the HE SU PPDU may be defined as follows.

In addition, the HE-SIG-A field of the HE MU PPDU may be defined as follows.

In addition, the HE-SIG-A field of the HE TB PPDU may be defined as follows.

The HE-SIG-B 740 may be included only in the case of a PPDU for multi-users (MUs) 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.

8 is a block diagram showing an example of HE-SIG-B according to the present embodiment.

As illustrated, the HE-SIG-B field includes a common field at the beginning, and it is possible to encode the common field separately from the following field. That is, as illustrated in FIG. 8, the HE-SIG-B field may include a common field including common control information and a user-specific field including user-specific control information. In this case, the common field includes a corresponding CRC field and the like and can be coded into one BCC block. The following user-specific fields may be coded into one BCC block, including a “user-feature field” for two users (2 users) and a CRC field corresponding thereto, as illustrated.

The previous field of HE-SIG-B 740 on the MU PPDU may be transmitted in a duplicated form. In the case of the HE-SIG-B 740, the HE-SIG-B 740 transmitted in a part of the frequency band (for example, the fourth frequency band) is the frequency band (that is, the fourth frequency band) of Control information for a data field in another frequency band (for example, a second frequency band) other than the data field and the corresponding frequency band may also be included. Further, the HE-SIG-B 740 of a specific frequency band (eg, the second frequency band) duplicates the HE-SIG-B 740 of another frequency band (eg, the fourth frequency band). It can be in one format. Alternatively, the HE-SIG-B 740 may be transmitted in an encoded form on all transmission resources. Fields after the HE-SIG-B 740 may include individual information for each receiving STA receiving the PPDU.

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

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

The size of the FFT/IFFT applied to the fields after the HE-STF 750 and the HE-STF 750 and the size of the FFT/IFFT applied to the fields before the HE-STF 750 may be different. 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 fields before the HE-STF 750. .

For example, at least one of L-STF 700, L-LTF 710, L-SIG 720, HE-SIG-A 730, and HE-SIG-B 740 on the PPDU of FIG. 7 When the field of is referred to as a first field, at least one of the data field 770, HE-STF 750, and HE-LTF 760 may be referred to as a second field. The first field may include fields related to legacy systems, and the second field may include fields related to HE systems. In this case, the fast Fourier transform (FFT) size/inverse fast Fourier transform (IFFT) size is N times the FFT/IFFT size used in the existing WLAN system (N is a natural number, for example, N=1, 2, 4). That is, FFT/IFFT of N(=4) times the 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 continuous 160 MHz or discontinuous 160 MHz bandwidth /IFFT can be applied.

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

Alternatively, an IDFT/DFT period applied to each symbol of the first field may be expressed as N(=4) times shorter than an 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) ). The length of the OFDM symbol may be a value obtained by adding the length of the guard interval (GI) to the 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, in FIG. 7, it is expressed that the frequency band used by the first field and the frequency band used by the second field are exactly the same, but in reality, they may not completely 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), but the interface may be inconsistent in each frequency band. This is because it may be difficult to precisely match the boundary surface since a plurality of null subcarriers, DC tones, and guard tones are inserted in the process of arranging the RUs as shown in FIGS. 4 to 6.

The user, that is, the receiving station may receive the HE-SIG-A 730 and receive instructions for receiving a 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 fields after the HE-STF 750 and the HE-STF 750. Conversely, if the STA is not instructed to receive the downlink PPDU based on the HE-SIG-A 730, the STA may stop decoding and set a network allocation vector (NAV). The cyclic prefix (CP) of the HE-STF 750 may have a size larger than that of other fields, and the STA may perform decoding on the downlink PPDU by changing the FFT size during this CP period.

Hereinafter, in this embodiment, the data (or frame) transmitted from the AP to the STA is downlink data (or downlink frame), and the data (or frame) transmitted from the STA to the AP is uplink data (or uplink frame). It can be expressed in terms. In addition, the transmission from the AP to the STA can be expressed in terms of downlink transmission and the transmission from the STA to the AP is uplink transmission.

In addition, each PDU (PHY protocol data unit), frame and data transmitted through the uplink transmission can be expressed in terms of downlink PPDU, downlink frame and downlink data. The PPDU may be a data unit including a PPDU header and a physical layer service data unit (PSDU) (or MAC protocol data unit (MPDU)). The PPDU header may include a PHY header and a PHY preamble, and the PSDU (or MPDU) may include a frame (or information unit of the MAC layer) or a data unit indicating a frame. The PHY header is a physical layer convergence protocol (PLCP) header in other terms, and the PHY preamble may be expressed as a PLCP preamble in other terms.

In addition, each PPDU, frame, and data transmitted through uplink transmission may be expressed in terms of uplink PPDU, uplink frame, and uplink data.

In the wireless LAN system to which the present embodiment is applied, it is possible that the entire bandwidth is used for downlink transmission to one STA and uplink transmission of one STA based on single (SU)-orthogonal frequency division multiplexing (OFDM) transmission. Do. In addition, in a wireless LAN system to which the present embodiment is applied, an AP may perform downlink (DL) multi-user (DL) transmission based on MU multiple input multiple output (MI MIMO), and such transmission is termed DL MU MIMO transmission. Can be expressed as

In addition, in the WLAN system according to the present embodiment, it is preferable that a transmission method based on orthogonal frequency division multiple access (OFDMA) is supported for uplink transmission and/or downlink transmission. That is, it is possible to perform uplink/downlink communication by allocating data units (eg, RUs) corresponding to different frequency resources to the user. Specifically, in the WLAN system according to the present embodiment, the AP may perform DL MU transmission based on OFDMA, and such transmission may be expressed in terms of DL MU OFDMA transmission. When DL MU OFDMA transmission is performed, the AP may transmit downlink data (or downlink frame, downlink PPDU) to each of the plurality of STAs through each of the plurality of frequency resources on the overlapped time resource. The plurality of frequency resources may be a plurality of subbands (or subchannels) or a plurality of resource units (RUs). DL MU OFDMA transmission can be used with DL MU MIMO transmission. For example, DL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) is performed on a specific sub-band (or sub-channel) allocated for DL MU OFDMA transmission. Can be.

In addition, in the WLAN system according to the present embodiment, UL MU transmission (uplink multi-user transmission) may be supported for multiple STAs to transmit data to the AP on the same time resource. Uplink transmission on the overlapped time resource by each of the plurality of STAs may be performed on a frequency domain or a spatial domain.

When the uplink transmission by each of the plurality of STAs is performed on the frequency domain, different frequency resources may be allocated as uplink transmission resources for each of the plurality of STAs based on OFDMA. Different frequency resources may be different subbands (or subchannels) or different resource units (RUs). Each of the plurality of STAs may transmit uplink data to the AP through different allocated frequency resources. The transmission method through these different frequency resources may be expressed in terms of a UL MU OFDMA transmission method.

When uplink transmission by each of the plurality of STAs is performed on the spatial domain, different space-time streams (or spatial streams) are allocated to each of the plurality of STAs, and each of the plurality of STAs transmits uplink data through different space-time streams. It can be transmitted to the AP. The transmission method through these different spatial streams may be expressed in terms of a UL MU MIMO transmission method.

UL MU OFDMA transmission and UL MU MIMO transmission may be performed together. For example, UL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) may be performed on a specific sub-band (or sub-channel) allocated for UL MU OFDMA transmission.

In a conventional WLAN system that does not support MU OFDMA transmission, a multi-channel allocation method is used to allocate a wide bandwidth (for example, a bandwidth exceeding 20 MHz) to one UE. When a single channel unit is 20 MHz, a multi-channel may include a plurality of 20 MHz channels. In the multi-channel allocation method, a primary channel rule is used to allocate a wide bandwidth to a terminal. When the primary channel rule is used, there is a limitation for allocating a wide bandwidth to the terminal. Specifically, according to the primary channel rule, when a secondary channel adjacent to the primary channel is used in the OBSS (overlapped BSS) and is'busy', the STA uses the remaining channels except the primary channel. Can't. Therefore, the STA is able to transmit the frame only through the primary channel, and thus is restricted for transmission of the frame through the multi-channel. That is, the primary channel rule used for multi-channel allocation in the existing WLAN system can be a big limitation in trying to obtain high throughput by operating a wide bandwidth in a current WLAN environment where there are not many OBSS.

In order to solve this problem, in this embodiment, a wireless LAN system supporting OFDMA technology is disclosed. That is, the OFDMA technique described above for at least one of downlink and uplink is applicable. In addition, the above-described MU-MIMO technique for at least one of downlink and uplink is additionally applicable. When OFDMA technology is used, multiple channels can be simultaneously used by multiple terminals, rather than one terminal, without limitations due to primary channel rules. Therefore, wide bandwidth operation is possible, and efficiency of radio resource operation can be improved.

As described above, when uplink transmission by each of a plurality of STAs (for example, non-AP STAs) is performed on a frequency domain, different frequency resources of the APs are increased for each of the plurality of STAs based on OFDMA. It can be allocated as a link transmission resource. Further, as described above, different frequency resources may be different subbands (or subchannels) or different resource units (RUs).

Different frequency resources for each of the plurality of STAs are indicated through a trigger frame.

9 shows an example of a trigger frame. The trigger frame of FIG. 9 allocates resources for uplink multiple-user transmission (MU transmission) and may be transmitted from the AP. The trigger frame may consist of a MAC frame and may be included in the PPDU. For example, it may be transmitted through the PPDU shown in FIG. 3, through the legacy PPDU shown in FIG. 2, or through a PPDU specifically designed for the trigger frame. If it is transmitted through the PPDU of FIG. 3, the trigger frame may be included in the illustrated data field.

Each field illustrated in FIG. 9 may be partially omitted, and other fields may be added. Also, the length of each field may be changed differently from that shown.

The frame control field 910 of FIG. 9 includes information on the version of the MAC protocol and other additional control information, and the duration field 920 is time information for NAV setting or an identifier of the terminal (eg For example, AID) may be included.

In addition, the RA field 930 includes address information of a receiving STA of a corresponding trigger frame, and may be omitted if necessary. The TA field 940 includes address information of an STA (eg, AP) that transmits the trigger frame, and the common information field 950 is applied to a receiving STA that receives the trigger frame. Contains control information. For example, a field indicating the length of the L-SIG field of the uplink PPDU transmitted corresponding to the trigger frame or the SIG-A field of the uplink PPDU transmitted corresponding to the trigger frame (ie, HE-SIG-A Field) may include information that controls the content. In addition, as the common control information, information on the length of the CP of the uplink PPDU transmitted corresponding to the trigger frame or information on the length of the LTF field may be included.

In addition, it is preferable to include individual user information (per user information) fields 960#1 to 960#N corresponding to the number of receiving STAs receiving the trigger frame of FIG. 9. The individual user information field may be referred to as an “assignment field”.

In addition, the trigger frame of FIG. 9 may include a padding field 970 and a frame check sequence field 980.

Each of the individual user information fields (960#1 to 960#N) shown in FIG. 9 preferably includes a plurality of sub-fields again.

10 shows an example of a sub-field included in a common information field. Some of the subfields of FIG. 10 may be omitted, and other subfields may be added. Also, the length of each of the illustrated sub-fields can be changed.

The trigger type field 1010 of FIG. 10 may indicate a trigger frame variant and encoding of a trigger frame variant. The trigger type field 1010 may be defined as follows.

The uplink bandwidth (UL BW) field 1020 of FIG. 10 indicates bandwidth in the HE-SIG-A field of the HE trigger-based (TB) PPDU. The UL BW field 1020 may be defined as follows.

The guard interval (Guard Interval, GI) and LTF type field 1030 of FIG. 10 indicate the GI and HE-LTF types of the HE TB PPDU response. The GI and LTF type field 1030 may be defined as follows.

In addition, when the GI and LTF type field 1030 has a value of 2 or 3, the MU-MIMO LTF mode field 1040 of FIG. 10 indicates the LTF mode of the UL MU-MIMO HE TB PPDU response. At this time, the MU-MIMO LTF mode field 1040 may be defined as follows.

If the trigger frame allocates the RU occupying the entire HE TB PPDU bandwidth and the RU is allocated to one or more STAs, the MU-MIMO LTF mode field 1040 is an HE single stream pilot HE-LTF mode or HE masked HE-LTF sequence mode It is indicated as one of.

If the trigger frame does not allocate RUs occupying the entire HE TB PPDU bandwidth and RUs are not allocated to one or more STAs, the MU-MIMO LTF mode field 1040 is indicated as HE single stream pilot HE-LTF mode. The MU-MIMO LTF mode field 1040 may be defined as follows.

11 shows an example of a sub-field included in a per user information field. Some of the subfields of FIG. 11 may be omitted, and other subfields may be added. Also, the length of each of the illustrated sub-fields can be changed.

The User Identifier field (or AID12 field, 1110) of FIG. 11 represents an identifier of a STA (ie, a receiving STA) to which individual user information (per user information) corresponds. An example of the identifier is all of the AID or It can be a part.

Also, a RU Allocation field 1120 may be included. That is, when the receiving STA identified by the user identifier field 1110 transmits an uplink PPDU in response to the trigger frame of FIG. 9, the corresponding uplink PPDU through the RU indicated by the RU Allocation field 1120 To send. In this case, the RU indicated by the RU Allocation field 1120 preferably indicates the RU shown in FIGS. 4, 5, and 6. The configuration of the specific RU allocation field 1120 will be described later.

The sub-field of FIG. 11 may include a (UL FEC) coding type field 1130. The coding type field 1130 may indicate a coding type of an uplink PPDU transmitted corresponding to the trigger frame of FIG. 9. For example, when BCC coding is applied to the uplink PPDU, the coding type field 1130 is set to '1', and when LDPC coding is applied, the coding type field 1130 is set to '0'. Can.

The sub-field of FIG. 11 may include a UL MCS field 1140. The MCS field 1140 may indicate an MCS technique applied to an uplink PPDU transmitted corresponding to the trigger frame of FIG. 9.

Also, the sub-field of FIG. 11 may include a trigger dependent user info field 1150. When the trigger type field 1010 of FIG. 10 indicates a Basic Trigger variant, the trigger dependent user information field 1150 includes MPDU MU Spacing Factor subfield (2 bits), TID Aggregation Limit subfield (3 bits), Reserved sub It may include a field (1 bit) and a Preferred AC subfield (2 bits).

Hereinafter, this specification proposes an example of improving the control field included in the PPDU. The control field improved by the present specification includes a first control field including control information required to interpret the PPDU and a second control field including control information for demodulating the data field of the PPDU. do. The first and second control fields may be various fields. For example, the first control field may be HE-SIG-A 730 illustrated in FIG. 7, and the second control field may be HE-SIG-B 740 illustrated in FIGS. 7 and 8. Can.

Hereinafter, a specific example of improving the first or second control field will be described.

In the following example, a control identifier inserted in the first control field or the second control field is proposed. The size of the control identifier may be various, for example, it may be implemented as 1-bit information.

The control identifier (eg, 1-bit identifier) may indicate whether 242-RU is allocated when, for example, 20 MHz transmission is performed. As shown in FIGS. 4 to 6, RUs of various sizes may be used. These RUs can be roughly divided into two types of RUs. For example, all RUs shown in FIGS. 4 to 6 may be divided into 26-type RUs and 242-type RUs. For example, a 26-type RU may include 26-RU, 52-RU, 106-RU, and a 242-type RU may include 242-RU, 484-RU, and larger RU.

The control identifier (eg, 1-bit identifier) may indicate that 242-type RU is used. That is, 242-RU may be included or 484-RU or 996-RU may be included. If the transmission frequency band through which the PPDU is transmitted is a 20 MHz band, 242-RU is a single RU corresponding to the full bandwidth of the transmission frequency band (ie, 20 MHz) band. Accordingly, the control identifier (eg, 1-bit identifier) may indicate whether a single RU corresponding to a full bandwidth of a transmission frequency band is allocated.

For example, if the transmission frequency band is a 40MHz band, the control identifier (e.g., 1-bit identifier) is assigned to a single RU corresponding to all bands of the transmission frequency band (i.e., 40MHz band) Can be instructed. That is, it may indicate whether or not 484-RU is allocated for 40MHz transmission.

For example, if the transmission frequency band is an 80MHz band, the control identifier (eg, 1-bit identifier) is assigned to a single RU corresponding to all bands of the transmission frequency band (ie, 80MHz band). Can be instructed. That is, it may indicate whether 996-RU is allocated for 80 MHz transmission.

Various technical effects can be achieved through the control identifier (for example, a 1-bit identifier).

First, when a single RU corresponding to all bands of a transmission frequency band is allocated through the control identifier (eg, 1-bit identifier), it is possible to omit allocation information of the RU. That is, since only one RU is allocated to all bands of the transmission frequency band, not a plurality of RUs, it is possible to omit the allocation information of the RU.

In addition, it can be used as a signaling for full-band multi-user MIMO (Full Bandwidth MU-MIMO). For example, when a single RU is allocated over a full bandwidth of a transmission frequency band, multiple users can be allocated to the single RU. That is, signals for each user are not distinguished in time and space, but other techniques (eg, spatial multiplexing) can be used to multiplex signals for multiple users in the same single RU. Accordingly, the control identifier (eg, 1-bit identifier) may be used to indicate whether to use the full-band multi-user MIMO as described above.

The common field included in the second control field (HE-SIG-B, 740) may include an RU allocation subfield. According to the PPDU bandwidth, the common field may include multiple RU allocation subfields (including N RU allocation subfields). The format of the common field can be defined as follows.

The RU allocation subfield included in the common field of the HE-SIG-B is composed of 8 bits, and can be indicated as follows for a 20 MHz PPDU bandwidth. RU allocation to be used in the data portion in the frequency domain indicates the size of the RU and the placement of the RU in the frequency domain as an index. The 8-bit RU allocation subfield for RU allocation and the mapping for the number of users per RU may be defined as follows.

The user-specific field included in the second control field (HE-SIG-B, 740) may include a user field, a CRC field, and a tail field. The format of the user-specific field can be defined as follows.

In addition, the user-specific field of the HE-SIG-B is composed of multiple user fields. The multiple user fields are located after the common fields of the HE-SIG-B. The location of the RU allocation subfield of the common field and the user field of the user-specific field together identifies the RU used to transmit the STA's data. Multiple RUs designated as a single STA are not allowed in a user-specific field. Therefore, signaling that enables the STA to decode its data is delivered in only one user field.

As an example, suppose that the RU allocation subfield is indicated by 8 bits of 01000010, indicating that 5 26-tone RUs are arranged after one 106-tone RU, and 3 user fields are included in the 106-tone RU. . At this time, the 106-tone RU may support multiplexing of three users. Eight user fields included in the user-specific field are mapped to six RUs, the first three user fields are assigned MU-MIMO in the first 106-ton RU, and the remaining five user fields are five 26- It may indicate that the tone is assigned to each RU.

The User field included in the user-specific field of the HE-SIG-B may be defined as follows. First, the user field for non-MU-MIMO allocation is as follows.

User fields for MU-MIMO assignment are as follows.

12 is a view showing an example of HE TB PPDU. The PPDU of FIG. 12 represents an uplink PPDU transmitted in response to the trigger frame of FIG. 9. At least one STA that has received the trigger frame from the AP may check the common information field and individual user information field of the trigger frame and transmit HE TB PPDU simultaneously with other STAs that have received the trigger frame.

As shown, the PPDU of FIG. 12 includes various fields, and each field corresponds to the fields shown in FIGS. 2, 3, and 7. Meanwhile, as illustrated, the HE TB PPDU (or uplink PPDU) of FIG. 12 may not include the HE-SIG-B field but only the HE-SIG-A field.

One. CSMA /CA (carrier sense multiple access/collision avoidance)

In IEEE 802.11, communication is performed in a shared wireless medium, so it has fundamentally different characteristics from a wired channel environment. For example, in a wired channel environment, communication was possible based on CSMA/CD (carrier sense multiple access/collision detection). For example, once a signal is transmitted from Tx, the channel environment does not change significantly, so Rx is transmitted without experiencing a large signal attenuation. At this time, when two or more signals collide, detection was possible. This is because the power sensed at the Rx stage is instantaneously greater than the power transmitted at Tx. However, in the wireless channel environment, various factors (for example, signal attenuation may be large depending on distance or may experience instantaneous deep fading) affect the channel. Tx cannot accurately perform carrier sensing. Therefore, in 802.11, a distributed coordination function (DCF), which is a carrier sense multiple access/collision avoidance (CSMA/CA) mechanism, was introduced. This performs clear channel assessment (CCA) sensing the medium for a specific duration (eg, DCF inter-frame space (DIFS)) before STAs (stations) having data to transmit transmit the data. At this time, if the medium is idle, the STA can transmit using the medium. However, if the medium is busy, data can be transmitted after waiting for another random backoff period in addition to DIFS under the assumption that several STAs are already waiting to use the medium. At this time, the random backoff period enables collision avoidance, because assuming that there are several STAs for transmitting data, each STA has a different probability of backoff interval and eventually has a different transmission time. to be. When one STA starts transmitting, other STAs cannot use the medium.

The random backoff time and procedure are as follows. When a certain medium changes from busy to idle, several STAs start preparing to send data. At this time, in order to minimize collision, STAs that want to transmit data each select a random backoff count and wait for the slot time. The random backoff count is a pseudo-random integer value, and one of the uniform distribution values in the [0 CW] range is selected. CW stands for contention window. The CW parameter takes the CWmin value as the initial value, but if the transmission fails, the value is doubled. For example, if an ACK response for a transmitted data frame is not received, collision may be considered. When the CW value has the CWmax value, the CWmax value is maintained until the data transmission is successful, and the data transfer succeeds and is reset to the CWmin value. At this time, it is desirable to maintain 2 ⁿ -1 for CW, CWmin, and CWmax for convenience of implementation and operation. Meanwhile, when the random backoff procedure is started, the STA selects a random backoff count within the [0 CW] range and continuously monitors the medium while the backoff slot counts down. In the meantime, if the medium becomes busy, the count down is stopped. When the medium becomes idle again, the countdown of the remaining backoff slot is resumed.

2. PHY procedure

In the PHY transmit/receive procedure in Wi-Fi, the detailed packet configuration method may be different, but it is as follows. It looks like this: For convenience, only 11n and 11ax are given as examples, but 11g/ac follows a similar procedure.

That is, the PHY transmit procedure is converted to a single PSDU (PHY service data unit) in the PHY stage when a MAC protocol data unit (MPDU) or an Aggregate MPDU (A-MPDU) comes from the MAC stage, and preamble and tail bits, padding bits (if necessary) ), and this is called a PPDU.

The PHY receive procedure is usually as follows. When energy detection and preamble detection (L/HT/VHT/HE-preamble detection for each Wifi version) are performed, information on PSDU configuration is obtained from the PHY header (L/HT/VHT/HE-SIG), MAC header is read, and data Read

3. Multi-band (or multi-link) aggregation

In the WLAN 802.11 system, to increase peak throughput, a wider band is used than the existing 11ax, or more streams are considered using more antennas. Also, the method of aggregation and use of various bands is considered.

In this specification, we propose a method of simultaneously transmitting data of HE STAs and EHT STAs using the same MU PPDU in consideration of wide bandwidth and multi-band (or multi-link) aggregation.

13 shows multiple channels allocated in the 5 GHz band.

Hereinafter, the “band” may include, for example, 2.4 GHz, 5 GHz, and 6 GHz bands. For example, in the 11n standard, 2,4 GHz band and 5 GHz band were supported, and in the 11ax standard, up to 6 GHz band was also supported. For example, in the 5 GHz band, multiple channels as shown in FIG. 13 may be defined. .

A multi-band wireless LAN system to which the technical features of the present specification are applied may be supported. That is, the transmitting STA transmits the PPDU through any channel (eg, 20/40/80/80+80/160 MHz, etc.) on the first band (eg, 5 GHz), for example, It is possible to transmit a PPDU on any channel (eg, 20/40/80/80+80/160/240/320 MHz) on a second band (eg, 6 GHz). (In this specification, the 240 MHz channel may be a continuous 240 MHz channel, or a combination of 80/160 MHz channels that are discontinuous to each other. In addition, the 320 MHz channel may be a continuous 320 MHz channel, or 80/160 MHz channels that are discontinuous to each other. It may be a combination of, for example, 240 MHz channels in this document may refer to contiguous 240 MHz channels, 80+80+80 MHz channels, or 80+160 MHz channels).

Also, the multi-band described in this document can be interpreted in various ways. For example, the transmitting STA sets one of the 20/40/80/80+80/160/240/320 MHz channels on the 6 GHz band as the first band, and another 20/40/80 on the 6 GHz band Any one of /80+80/160/240/320 MHz channels may be set as the second band, and multi-band transmission (ie, transmission supporting both the first band and the second band) may be performed. For example, the transmitting STA may simultaneously transmit the PPDU through the first band and the second band, or may transmit through only one band at a specific time.

At least one of the primary 20 MHz and secondary 20/40/80/160 MHz channels described below may be transmitted in the first band, and the other channels may be transmitted in the second band. Or, all channels may be transmitted in the same single band.

In this specification, the term “band” may be replaced with “link”.

The following describes a control signaling method for multi-band aggregation. The control signaling method may employ a Fast Session Transfer (FST) setting method, and the FST setting protocol will be described below.

The FST setup protocol consists of four states and rules on how to move from one state to the next. The four states are Initial, Setup Completed, Transition Done and Transition Confirmed. In the initial state, the FST session operates on one or two bands/channels. In the Setup Complete state, the initiator and responder are ready to change the currently active band/channel(s). The FST session may be delivered in whole or in part to other bands/channels. The Transition Done state enables the initiator and the responder to operate in different bands/channels when the LLT (Link Loss Timeout) value is 0. Both initiators and responders must successfully communicate in the new band/channel to reach the Transition Confirmed state. The state transition diagram of the FST establishment protocol is shown in FIG. 14.

14 shows four states of the FST setting protocol.

15 shows the procedure of the FST establishment protocol.

FIG. 15 shows the procedure of the FST setting protocol for driving the state machine shown in FIG. 14. 15 is an example of a basic procedure and does not cover all possible uses of the protocol. In FIG. 15, MAC Layer Management Entity (MLME) 1 and MLME 2 represent any two MLMEs of a device capable of multi-band according to the reference model described in Reference Model for Multi-band Operation. As described later, the exchange of the FST Setup Request and the FST Setup Response frame is repeated as necessary until the FST initiator and the FST responder successfully move to the Setup Completed state. 15 illustrates the operation of the procedure of the FST establishment protocol.

In order to establish an FST session in the initial state and deliver it to the Setup Completed state of the FST configuration protocol, the initiator and the responder must exchange the FST Setup Request and FST Setup Response frames. The FST session exists in the Setup Completed state, Transition Done state, or Transition Confirmed state. In the Initial state and Setup Completed state, the old band/channel indicates a frequency band/channel through which the FST session will be delivered, and the new band/channel indicates a frequency band channel through which the FST session will be delivered. In the Transition Done state, the new band/channel indicates the frequency band/channel through which the FST Ack Request and FST Ack Response frames are transmitted, and the old band/channel indicates the frequency band/channel through which the FST session is transmitted.

When the Respondent accepts the FST Setup Request, the Status Code field is set to SUCCESS and the Status Code is set to REJECTED_WITH_SUGGESTED_CHANGES, and one or more parameters in the FST installation request frame are invalid and an alternative parameter must be proposed. In addition, the responder sets the Status Code field to PENDING_ADMITTING_FST_SESSION or PENDING_GAP_IN_BA_WINDOW to indicate that the FST setting request is pending, and sets the Status Code field to REQUEST_DECLINED to reject the FST Setup Request frame.

The responder who is an enabling STA indicates that the FST Setup Request frame was rejected because it was initialized by a subordinate STA requesting a switch to a frequency band to which the DSE procedure is applied by setting the Status Code to REJECT_DSE_BAND. At this time, when the responder is an enabling STA for a subordinate STA, the responder may include a Timeout Interval element in the FST Setup Response frame to indicate a period within the TU before starting FST setup with the subordinate STA. The Timeout Interval Type field in the Timeout Interval element should be set to 4. The responder can use the parameters in the FST Setup Request frame received from the dependent STA to initiate the FST setup with the initiator.

Respondent STA and not possible responder must reject all FST Setup Request frames received to switch to the frequency band covered by DSE procedure, except when the transmitter of the FST Setup Request frame is the enabling STA of the slave STA. .

4. Examples applicable to the present invention

16 shows an example of multi-band aggregation using the 2.4 GHz band and the 5 GHz band.

Referring to FIG. 16, the AP and the STA may transmit and receive data by aggregation of the 2.4 GHz and 5 GHz bands. Such multi-band aggregation can be aggregated in any band of 1 to 7.125 GHz as well as 2.4/5 GHz, and can be aggregated using multiple RFs in the same band (eg, 5 GHz). Therefore, by using multi-band aggregation or multiple RFs in the same band, there is an opportunity to use a bandwidth of 160 MHz or more (for example, 320 MHz) as well as the bandwidth used in the existing 802.11.

In the structure shown in FIG. 16, in order to perform contention as before, a backoff is performed for one 20 MHz primary channel (Primary 20 or P20) determined regardless of multi-band, and the moment at which transmission is possible at P20 (backoff count = 0) The transmission bandwidth is determined by determining whether the secondary channel is IDLE/BUSY during PIFS (or DIFS).

However, since a fairly wide bandwidth of 160 MHz or more can be used, a secondary channel having a wide bandwidth such as a 160 MHz secondary channel (Secondary 160) and a 320 MHz secondary channel (Secondary 320) may exist. Particularly, in a dense environment, the availability of such secondary channels is likely to be BUSY, so the availability is significantly reduced. In addition, if CCA is performed on a secondary channel according to the existing CCA rule (Primary 20 -> Secondary 20 -> Secondary 40 …), band aggregation combination, not 20/40/80/160/320MHz unit size (eg 120MHz(40 +80), 240MHz (80+160), etc., cannot use the existing rule.

Therefore, in this specification, to solve the above-described problem, we propose a method for contention by placing a primary channel for each band (or RF).

17 shows an example in which a primary channel exists in each band (or RF) when performing multi-band aggregation.

When aggregation of 160MHz in the 5GHz band and 160MHz in the 6GHz band is performed as shown in FIG. 17, P20 exists in each band, and P20 may exist regardless of the bandwidth size applied in each band (or RF) (however, more than 20MHz). .

Basically, the Wi-Fi system performs contention based on one P20, and in the EDCA function (EDCAF), a backoff that is randomly selected between the contention window (CW) value and 0 to CW for contention for each access category (AC). count (BC) is required. Therefore, when multiple primary channels exist, that is, when the primary channels exist in each band (or RF), a new contention rule is required for frame transmission, and CW and BC can be applied as follows.

A. It has a common CW for all P20s, and a separate BC is applied to each P20.

In the case of Method A, the BC decrement rule for each primary channel can be flexibly applied by applying it as before, but more processing overhead is required. In addition, a CW adjustment method for the success of transmission for each band is additionally required.

B. Common CW and BC applied to all P20s

In the case of method B, regardless of the number of primary channels, one CW and BC can be maintained as before, but a new BC decrement rule according to the channel state of each P20 is required.

C. It has a separate CW for each P20, and a separate BC for each P20.

In the case of the C method, the BC decrement rule for each primary channel and the CW adjustment method according to whether or not transmission is successful can be flexibly applied by applying as before, but more processing overhead is required.

When Method B is applied, the BC decrement rule can be applied as follows.

1) BC value is decreased when the channel status of all P20 is IDLE

-> Since all P20s are integrated, collision probability can be reduced, but transmission latency can be increased.

2) BC value is decreased when at least one channel status among all P20s is IDLE

->1) Transmission latency may be reduced compared to the method, but collision probability may be increased because other P20s ignore the case of BUSY.

18 shows an example of applying the BC decrement rule of the B-2) method in the case of aggregation of the 2.4 GHz, 5 GHz, and 6 GHz bands.

In this example, to show a simple process, CCA during IFS after BUSY is omitted and only the process of reducing the backoff count is shown. In FIG. 16, the common BC value is initially selected as 3, and the BC is decreased according to the channel state of each P20. In slot 1, slot 3, and slot 4, one or more P20s are IDLE, reducing BC, and in slot 2, they are all BUSY, so they maintain BC.

5. Offered Example

This specification proposes a method for enabling fast and efficient power saving when transmitting flexible UL/DL using multi-band in an existing wireless LAN system.

19 is an example of applying an FDD scheme to a wireless LAN system.

19, DL carrier occupies 160 MHz and UL carrier occupies 160 MHz or 20 MHz. However, this is only an example, and DL and UL may occupy different BWs, and DL BWs and UL BWs need not be the same.

Also, DL and UL may be located in the same band, but may be located in different bands. For example, DL may be defined in the 5 GHz band, and UL may be defined in the 2.4 GHz band. The opposite is also possible.

5.1. How to propose PPDU for flexible transmission

20 is an example in which DL or UL transmission is performed in a TDD scheme in a multi-band environment.

Flexible UL/DL can be operated as the following example. FIG. 20 transmits a DL PPDU in channel 1, while UL/DL transmission in channel 2 occurs flexibly.

In order to operate as above, the RF chain for each DL and UL must be configured separately. Also, in order to transmit and receive at the same time, two baseband modules must also be provided.

In this specification, we propose an efficient power saving technique for flexible transmission in such multi-band.

In the current Wi-Fi system, different data can be transmitted in each channel band. This specification proposes a method of performing power saving in all multi-bands or a part using features that can transmit different data in each channel band. At this time, by adjusting data between bands for efficient power saving, power saving efficiency in a multi-band can be increased.

This specification proposes a method of efficiently applying power saving of 802.11 to multi-band as an example. The data queue for flexible UL/DL between bands in multi-band can be operated as one of the following.

5.2. Suggested above PPDU How to operate data using

The method in which a plurality of ULs and DLs are allocated to a secondary channel can be operated differently depending on which type of queues for multiple channel bands in the Wi-Fi system follow.

1) Independent data queue operation for each channel band (band-specific)

21 is an example of operating an independent data queue for each channel band in a multi-band environment.

As shown in FIG. 21, when an independent data queue is operated for each channel band, a channel band (referred to as a secondary band) having no data to send or relatively small data may occur. In this case, during the time that the DL PPDU is allocated in the primary channel, the secondary channel may operate as follows according to the data situation of the queue.

<If there is data in the queue>

-After the transmission of the first data (DL) of the queue, the STA receiving the DL PPDU transmitted through the secondary channel is after SIFS (a value other than SIFS may be applied. For example, a value larger than SIFS and smaller than PIFS) UL PPDU is transmitted. In order to increase flexibility, an STA other than the STA where the AP transmitted the DL PPDU may transmit the UL PPDU. Alternatively, a DL PPDU for another STA may be transmitted other than the UL PPDU. At this time, the maximum length of the UL PPDU is set to be equal to or shorter than the end point of the DL PPDU transmitted through the primary channel. During the period until the transmission of the UL is finished and DL PPDU transmission is completed in the primary channel, the secondary channel may operate as follows.

-> Data in the queue is transmitted during the interval.

-> Or, if there is data in the queue that has a length that can be transmitted during the section, it is transmitted.

-The above process can be repeated until one of the following is satisfied.

-> When the PPDU transmission ends on the primary channel

-> Or, a certain time (pre-defined time) before PPDU transmission is ended on the defined primary channel.

-> When it is determined that there is no more data to transmit in the queue of the secondary channel

<If there is no data in the queue>

-The STA that has not received any DL PPDU in the secondary channel transmits the UL PPDU after the SIFS in which the PPDU is transmitted in the primary channel. Alternatively, values other than SIFS may be applied. (For example, a value larger than SIFS and smaller than PIFS) At this time, the maximum length of the UL PPDU is set equal to or shorter than the end point of the DL PPDU transmitted to the primary channel. During the period until the transmission of the UL is finished and DL PPDU transmission is completed in the primary channel, the secondary channel may operate as follows.

-> If the highest priority data of the queue can be transmitted during the interval, it is transmitted.

-> Or, if there is data in the queue that has a length that can be transmitted during the section, it is transmitted.

-The above process can be repeated until one of the following is satisfied.

-> When the PPDU transmission ends on the primary channel

-> Or, a certain time (pre-defined time) before PPDU transmission is ended on the defined primary channel.

-> When it is determined that there is no more data to transmit in the queue of the secondary channel

Alternatively, a plurality of channels described as secondary channels may be operated.

2) When multiple channel bands share and operate the integrated data queue (common queue)

22 is an example in which a plurality of channel bands share and operate an integrated data queue in a multi-band environment.

When a plurality of channel bands are operated as one data queue as shown in FIG. 22, in a secondary channel that transmits a relatively short PPDU during a time when a DL PPDU is allocated in a primary channel, it may be operated as follows according to the data situation of the queue. .

After transmitting the allocated DL PPDU, the STA receiving the DL PPDU transmits the UL PPDU after SIFS. Alternatively, values other than SIFS may be applied. (For example, a value larger than SIFS and smaller than PIFS) At this time, the maximum length of the UL PPDU is set equal to or shorter than the end point of the DL PPDU transmitted to the primary channel.

During the period before transmission of the UL is finished and DL PPDU transmission is completed in the primary channel, the secondary channel may operate as follows.

-Data in the queue is transmitted during the interval.

-Or, if there is data in the queue that has a length that can be transmitted during that section, it is transmitted.

The above process can be repeated until one of the following is satisfied.

-When PPDU transmission is ended in the primary channel

-Or, a certain time (pre-defined time) before PPDU transmission is ended on the defined primary channel.

-When it is determined that there is no more data to transmit in the secondary channel queue

In addition, a plurality of channels described and referred to as secondary channels may be operated.

5.3. Examples of efficient power saving procedures

Unlike the existing single-band, the AP can determine which band to send data to, and use it to operate efficient power saving between multi-bands. In this specification, we propose power saving that can be applied to both cases.

When using multi-band, when transmitting PPDU in one band, if power saving is possible without transmitting/receiving data in the other band while transmitting the corresponding PPDU, this situation can be informed to save power in the other band during PPDU transmission time. have. 23 is an example of such a case.

23 shows an example in which power saving is performed in multiple bands.

Example 1) While the AP transmits the PPDU to the STA X through channel band1 (from the start point to the end of the PPDU transmission, referring to FIG. 23, 1st duration (duration) and 2nd duration), the AP is another STA through channel band2 Y and PPDU can be transmitted and received. However, in FIG. 23, only PPDU transmission and reception between AP and STA X is illustrated, and PPDU transmission and reception between AP and STA Y is not illustrated.

Referring to FIG. 23, STA X can save power in channel band 2, which is a channel band other than channel band 1 receiving PPDU. That is, STA X performs power saving in channel band2 during 1 ^st duration and 2 ^nd duration, and does not transmit and receive PPDUs, so it can switch to a doze state.

In addition, STA X is band1 channel does not transmit and receive a PPDU transmitted PPDU in band2 channel, and for a 3 ^rd duration may perform the power saving. Accordingly, STA X may switch channel band1 to the doze state during the 3 ^rd duration.

Example 2) When a channel band other than the channel band through which the PPDU is transmitted is BUSY

Referring to FIG. 23, when channel band2, not channel band1 where the AP transmits a PPDU to STA X, is BUSY, STA X cannot transmit/receive PPDUs, so power saving is performed on channel band2 to switch to the doze state. .

Example 3) When transmitting a PPDU to STA X, the AP does not transmit/receive PPDUs through other channel bands.

Referring to FIG. 23, when there is no transmission/reception of PPDU in channel band1 while DL PPDU is transmitted in channel band2 (during 3 ^rd duration), power saving can be performed in channel band1 during PPDU transmission time in channel band2 The AP may inform STA X. At this time, in channel band1, it is instructed that there is no data transmission until the end of DL PPDU transmission of channel band2, and the power saving mode is maintained until the end of DL PPDU transmission of channel band2. Here, power saving may be one of the following operations.

-Power saving in baseband layer

-RF power saving in the channel band

-Power saving for carrier sensing

-Power saving to maintain Doze state

5.4. How to signal power saving

At this time, in Example 3, a method in which a PPDU transmitted in a specific band, such as a DL PPDU of channel band2, can inform or indicate power saving of another band is as follows. Hereinafter, a PPDU transmitted in a specific band is referred to as a transmission PPDU.

-SIG field of the transmission PPDU

-When a PPDU other than the transmitted PPDU is transmitted, some of the fields included in the PPDU

-Some of the fields transmitted in the MAC frame

The following information can be reported using the integer N bits among the frames presented above.

A. How to inform whether data transmission exists in a band other than the currently transmitted band

The 1 (or integer N) bit is used to indicate whether power saving is possible in a band other than the band to which the current PPDU is transmitted. The value of the corresponding bit can be set as follows. (Value setting can be changed)

i. 0: Until the end of transmission of the currently transmitted PPDU, data transmission occurs only in the corresponding channel band.

ii. 1: Transmission may occur in another band before the end of transmission of the currently transmitted PPDU.

B. How to tell if data transmission exists in a specific band

By setting the N bit, it indicates that data transmission occurs only in the channel band of the corresponding number. The N bit value can be set as follows. (The value can be set differently)

i. 0: Transmission may occur in all channel bands

ii. A positive integer value other than 0: It indicates that data transmission occurs only in the channel band of the corresponding number. This information is valid until the end of the transmitted PPDU.

Hereinafter, the above-described embodiment will be described with reference to FIGS. 14 to 23.

24 is a flowchart illustrating a procedure for an AP to perform power saving according to this embodiment.

The example of FIG. 24 may be performed in a network environment in which a next generation wireless LAN system is supported. The next-generation wireless LAN system is an improved wireless LAN system that can satisfy backward compatibility with the 802.11ax system. The next generation WLAN system may correspond to an Extreme High Throughput (EHT) WLAN system or an 802.11be WLAN system.

This embodiment proposes a method for performing efficient power saving by using multi-band aggregation and TDD in a next-generation wireless LAN system such as EHT.

The example of FIG. 24 is performed by an AP, and the first and second STAs of FIG. 24 may correspond to an STA supporting an Extreme High Throughput (EHT) WLAN system. The AP and the first and second STAs may support multiple bands (or multiple links).

In step S2410, the AP (Access Point) transmits the first data to the first STA (Station) during the first duration through the first band.

In step S2420, the AP transmits the second data to the second STA through the second band while the first data is transmitted.

In step S2430, the AP performs power saving in the second band for the first STA during the first duration.

The first band and the second band are aggregated with each other in a multi-band. The first band includes a first primary channel, and the second band includes a second primary channel.

If the multiple bands are combined into only two bands, the first band may be a 2.4 GHz or 5 GHz band, and the second band may be a 6 GHz band. If the third band of the multi-band is further combined, the first band may be the 2.4 GHz band, the second band may be the 5 GHz band, and the third band may be the 6 GHz band. However, the configuration of the above-described band is only an example, and the wireless LAN system may support various numbers of bands and channels.

The multi-band supports DL transmission and UL transmission at the same time. This is called FDU (Flexible DL/UL) transmission. FDU transmission is a transmission technique that can increase TSS/Rx average throughput by simultaneously enabling Tx/Rx transmission in multiple bands.

The first STA is switched to a doze state in the second band during the first duration. That is, the first STA receives the first data (or first PPDU) in the first band, but the second STA receives the second data (or second PPDU) in the second band for the same time. Therefore, the first STA may perform power saving for the second band. During the first duration, since the second STA is receiving the second data in the second band, the first STA cannot use the channel of the second band during the corresponding time. The first STA may switch to a doze state for the second band during the first duration.

Further, the AP may transmit third data to the first STA during the second duration through the first band. When the channel of the second band is BUSY during the second duration, the AP may perform the power saving in the second band for the first STA. In this case, the first STA may be switched to the doze state in the second band during the second duration. That is, since the channel of the second band is BUSY during the second duration, the first STA cannot use the channel of the second band during the corresponding time. Accordingly, the first STA may switch to the doze state for the second band during the first duration.

In addition, the AP may transmit the fourth data to the first STA during the third duration through the second band. When there is no data to be transmitted in the first band during the third duration, the AP may perform the power saving in the first band for the first STA. The first STA may switch to a doze state in the first band during the third duration. That is, since there is no data to be transmitted in the first band during the third duration, the first STA does not use the channel of the first band during the corresponding time. Accordingly, the first STA may switch to the doze state for the first band during the third duration.

Also, the fourth data may include information that there is no data to be transmitted in the first band during the third duration. Accordingly, the first STA can know that there is no data transmission in the first band until the transmission of the fourth data is transmitted in the second band, until the transmission of the fourth data ends (the Power saving).

Each of the multi-bands can also be applied to the TDD technique. Accordingly, accordingly, the first and second data are transmitted during the first duration, the third data is transmitted during the second duration, and the fourth data is transmitted during the third duration. However, the first to third durations do not overlap in the time domain. That is, the first to third durations may be distinguished from each other in different sections in a time domain by applying a TDD technique to the multiple bands. Accordingly, the first duration, the second duration, and the third duration may be time intervals sequentially transmitted.

The power saving includes power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state It can be power saving.

The first and third data may include first information on power saving in the second band, and the fourth data may include second information on power saving in the first band.

The first information may be included in a signal field or MAC frame of the first and third data, and the second information may be included in a signal field or MAC frame of the fourth data.

The fourth data may include third information about whether there is data to be transmitted in the first band. The third information may be set as one bit. For example, if there is data to be transmitted in the first band (specific band), the bit may be set to 1, and if there is no data to be transmitted in the first band, the bit may be set to 0.

The first band and the second band may represent channels. Accordingly, the first band may be a primary channel of a specific band, and the second band may be a secondary channel of a specific band.

In addition, the first band may be a band including a primary channel, and the second band may be a band including a secondary channel.

Hereinafter, a signaling method for multi-band aggregation will be described. In this embodiment, it has been described as receiving configuration information for multiple bands, and signaling may be performed by using the FST configuration method.

The transmitting device and the receiving device described below may be the aforementioned AP or the first and second STAs. The transmitting device may transmit a multi-band setting request frame to the receiving device. The transmitting device may receive a multi-band setting response frame from the receiving device.

The transmitting device may transmit a multi-band Ack request frame to the receiving device. The transmitting device may receive a multi-band Ack response frame from the receiving device.

The transmitting device may include a first Station Management Entity (SME), a first MAC Layer Management Entity (MLME), and a second MLME. The receiving device may include a second SME, a third MLME, and a fourth MLME.

The first MLME and the third MLME are entities supporting the first band, and the second MLME and the fourth MLME may be entities supporting the second band.

The multi-band setup request frame and the multi-band setup response frame may be transmitted and received between the first MLME and the third MLME. The multi-band Ack request frame and the multi-band Ack response frame may be transmitted and received between the second MLME and the fourth MLME.

The first and second SME may generate primitives including multi-band parameters. The multi-band parameter may include a channel number designated in the multi-band, an operating class, and a band ID (identifier). The primitive may be delivered to the first to fourth MLME.

When the multi-band method borrows the FST setting method, it includes four states, and is composed of rules for a method of moving from one state to the next. The four states are Initial, Setup Completed, Transition Done and Transition Confirmed.

In the Initial state, the transmitting device and the receiving device communicate in an old band/channel. At this time, when the FST setup request frame and the FST setup response frame are transmitted and received between the transmitting apparatus and the receiving apparatus, the system moves to a Setup Complete state, and the transmitting apparatus and the receiving apparatus are ready to change the currently operating band/channel(s). do. The FST session may be delivered in whole or in part to other bands/channels.

When the value of the LLT included in the FST setup request frame is 0, it moves from the Setup Complete state to the Transition Done state, and allows the transmitting device and the receiving device to operate in different bands/channels.

Both the transmitting and receiving devices must successfully communicate in a new band/channel to reach the Transition Confirmed state. At this time, when the FST Ack request frame and the FST Ack response frame are transmitted and received between the transmitting device and the receiving device, the device moves to a Transition Confirmed state, and the transmitting device and the receiving device form a complete connection in a new band/channel.

25 is a flowchart illustrating a procedure for a STA to perform power saving according to this embodiment.

The example of FIG. 25 may be performed in a network environment in which a next generation wireless LAN system is supported. The next-generation wireless LAN system is an improved wireless LAN system that can satisfy backward compatibility with the 802.11ax system. The next generation WLAN system may correspond to an Extreme High Throughput (EHT) WLAN system or an 802.11be WLAN system.

This embodiment proposes a method for performing efficient power saving by using multi-band aggregation and TDD in a next-generation wireless LAN system such as EHT.

The example of FIG. 25 is performed by the first STA, and the first STA and the second STA can correspond to an STA supporting an Extreme High Throughput (EHT) wireless LAN system. The AP of FIG. 25 and the first and second STAs may support multiple bands (or multiple links).

In step S2510, the first STA (Station) receives the first data from the AP (Access Point) through the first band.

In step S2520, the first STA performs power saving in the second band during the first duration.

The first band and the second band are aggregated with each other in a multi-band. The first band includes a first primary channel, and the second band includes a second primary channel.

If the multiple bands are combined into only two bands, the first band may be a 2.4 GHz or 5 GHz band, and the second band may be a 6 GHz band. If the third band of the multi-band is further combined, the first band may be the 2.4 GHz band, the second band may be the 5 GHz band, and the third band may be the 6 GHz band. However, the configuration of the above-described band is only an example, and the wireless LAN system may support various numbers of bands and channels.

The multi-band supports DL transmission and UL transmission at the same time. This is called FDU (Flexible DL/UL) transmission. FDU transmission is a transmission technique that can increase TSS/Rx average throughput by simultaneously enabling Tx/Rx transmission in multiple bands.

The first STA is switched to a doze state in the second band during the first duration. That is, the first STA receives the first data (or first PPDU) in the first band, but the second STA receives the second data (or second PPDU) in the second band for the same time. Therefore, the first STA may perform power saving for the second band. During the first duration, since the second STA is receiving the second data in the second band, the first STA cannot use the channel of the second band during the corresponding time. The first STA may switch to a doze state for the second band during the first duration.

Further, the AP may transmit third data to the first STA during the second duration through the first band. When the channel of the second band is BUSY during the second duration, the AP may perform the power saving in the second band for the first STA. In this case, the first STA may be switched to the doze state in the second band during the second duration. That is, since the channel of the second band is BUSY during the second duration, the first STA cannot use the channel of the second band during the corresponding time. Accordingly, the first STA may switch to the doze state for the second band during the first duration.

In addition, the AP may transmit the fourth data to the first STA during the third duration through the second band. When there is no data to be transmitted in the first band during the third duration, the AP may perform the power saving in the first band for the first STA. The first STA may switch to a doze state in the first band during the third duration. That is, since there is no data to be transmitted in the first band during the third duration, the first STA does not use the channel of the first band during the corresponding time. Accordingly, the first STA may switch to the doze state for the first band during the third duration.

Also, the fourth data may include information that there is no data to be transmitted in the first band during the third duration. Accordingly, the first STA can know that there is no data transmission in the first band until the transmission of the fourth data is transmitted in the second band, until the transmission of the fourth data ends (the Power saving).

Each of the multi-bands can also be applied to the TDD technique. Accordingly, accordingly, the first and second data are transmitted during the first duration, the third data is transmitted during the second duration, and the fourth data is transmitted during the third duration. However, the first to third durations do not overlap in the time domain. That is, the first to third durations may be distinguished from each other in different sections in a time domain by applying a TDD technique to the multiple bands. Accordingly, the first duration, the second duration, and the third duration may be time intervals sequentially transmitted.

The power saving includes power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state It can be power saving.

The first and third data may include first information on power saving in the second band, and the fourth data may include second information on power saving in the first band.

The first information may be included in a signal field or MAC frame of the first and third data, and the second information may be included in a signal field or MAC frame of the fourth data.

The fourth data may include third information about whether there is data to be transmitted in the first band. The third information may be set as one bit. For example, if there is data to be transmitted in the first band (specific band), the bit may be set to 1, and if there is no data to be transmitted in the first band, the bit may be set to 0.

The first band and the second band may represent channels. Accordingly, the first band may be a primary channel of a specific band, and the second band may be a secondary channel of a specific band.

In addition, the first band may be a band including a primary channel, and the second band may be a band including a secondary channel.

Hereinafter, a signaling method for multi-band aggregation will be described. In this embodiment, it has been described as receiving configuration information for multiple bands, and signaling may be performed by using the FST configuration method.

The transmitting device and the receiving device described below may be the aforementioned AP or the first and second STAs. The transmitting device may transmit a multi-band setting request frame to the receiving device. The transmitting device may receive a multi-band setting response frame from the receiving device.

The transmitting device may transmit a multi-band Ack request frame to the receiving device. The transmitting device may receive a multi-band Ack response frame from the receiving device.

The transmitting device may include a first Station Management Entity (SME), a first MAC Layer Management Entity (MLME), and a second MLME. The receiving device may include a second SME, a third MLME, and a fourth MLME.

The first MLME and the third MLME are entities supporting the first band, and the second MLME and the fourth MLME may be entities supporting the second band.

The multi-band setup request frame and the multi-band setup response frame may be transmitted and received between the first MLME and the third MLME. The multi-band Ack request frame and the multi-band Ack response frame may be transmitted and received between the second MLME and the fourth MLME.

The first and second SME may generate primitives including multi-band parameters. The multi-band parameter may include a channel number designated in the multi-band, an operating class, and a band ID (identifier). The primitive may be delivered to the first to fourth MLME.

When the multi-band method borrows the FST setting method, it includes four states, and is composed of rules for a method of moving from one state to the next. The four states are Initial, Setup Completed, Transition Done and Transition Confirmed.

In the Initial state, the transmitting device and the receiving device communicate in an old band/channel. At this time, when the FST setup request frame and the FST setup response frame are transmitted and received between the transmitting apparatus and the receiving apparatus, the system moves to a Setup Complete state, and the transmitting apparatus and the receiving apparatus are ready to change the currently operating band/channel(s). do. The FST session may be delivered in whole or in part to other bands/channels.

When the value of the LLT included in the FST setup request frame is 0, it moves from the Setup Complete state to the Transition Done state, and allows the transmitting device and the receiving device to operate in different bands/channels.

Both the transmitting and receiving devices must successfully communicate in a new band/channel to reach the Transition Confirmed state. At this time, when the FST Ack request frame and the FST Ack response frame are transmitted and received between the transmitting device and the receiving device, the device moves to a Transition Confirmed state, and the transmitting device and the receiving device form a complete connection in a new band/channel.

6. Device Configuration

26 is a diagram for describing an apparatus for implementing the method as described above.

The wireless device 100 of FIG. 26 is a transmission device capable of implementing the above-described embodiment, and may operate as an AP STA. The wireless device 150 of FIG. 26 is a receiving device capable of implementing the above-described embodiment, and may operate as a non-AP STA.

The transmitting device 100 may include a processor 110, a memory 120, and a transmitting and receiving unit 130, and a receiving device 150 includes a processor 160, a memory 170, and a transmitting and receiving unit 180 can do. The transmitting and receiving units 130 and 180 transmit/receive wireless signals and may be executed in a physical layer such as IEEE 802.11/3GPP. The processors 110 and 160 are executed in the physical layer and/or the MAC layer, and are connected to the transceivers 130 and 180.

The processors 110 and 160 and/or the transceivers 130 and 180 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and/or data processors. The memories 120 and 170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage units. When an embodiment is executed by software, the above-described method may be executed as a module (eg, process, function) that performs the above-described function. The module can be stored in the memory (120, 170), it can be executed by the processor (110, 160). The memory 120 or 170 may be disposed inside or outside the process 110 or 160, and may be connected to the process 110 or 160 by well-known means.

The processors 110 and 160 may implement the functions, processes, and/or methods proposed herein. For example, the processors 110 and 160 may perform operations according to the above-described embodiment.

The operation of the processor 110 of the transmitting device is specifically as follows. The processor 110 of the transmitting device transmits the first data to the first STA during the first duration through the first band, and transmits the second data to the second STA through the second band while the first data is being transmitted. And performs power saving in the second band for the first STA during the first duration.

The operation of the processor 160 of the receiving device is specifically as follows. The processor 160 of the receiving device receives the first data from the AP during the first duration through the first band, and while the first data is being transmitted, the second data from the AP to the second STA is second. It is received through a band and performs power saving in the second band during the first duration.

27 shows a more detailed wireless device implementing an embodiment of the present invention. The present invention described above for the transmitting device or the receiving device can be applied to this embodiment.

The wireless device includes a processor 610, a power management module 611, a battery 612, a display 613, a keypad 614, a subscriber identification module (SIM) card 615, a memory 620, and a transceiver 630 ), one or more antennas 631, a speaker 640, and a microphone 641.

The processor 610 can be configured to implement the proposed functions, procedures and/or methods described herein. Layers of the radio interface protocol may be implemented in the processor 610. The processor 610 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and/or data processing devices. The processor may be an application processor (AP). The processor 610 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). Examples of processors 610 include SNAPDRAGONTM series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, A series processors manufactured by Apple®, HELIOTM series processors manufactured by MediaTek®, and INTEL®. It may be an ATOMTM series processor manufactured by or a corresponding next-generation processor.

The power management module 611 manages power for the processor 610 and/or the transceiver 630. The battery 612 supplies power to the power management module 611. The display 613 outputs the results processed by the processor 610. Keypad 614 receives input to be used by processor 610. The keypad 614 may be displayed on the display 613. The SIM card 615 is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) used to identify and authenticate subscribers in mobile phone devices such as mobile phones and computers, and keys associated therewith. Many SIM cards can also store contact information.

The memory 620 is operatively coupled with the processor 610, and stores various information for operating the processor 610. The memory 620 may include read-only memory (ROM), random access memory (RAM), flash memory, a memory card, a storage medium, and/or other storage devices. When the embodiment is implemented in software, the techniques described herein may be implemented as a module (eg, procedure, function, etc.) that performs the functions described herein. Modules may be stored in memory 620 and executed by processor 610. The memory 620 may be implemented inside the processor 610. Alternatively, the memory 620 may be implemented outside the processor 610 and may be communicatively connected to the processor 610 through various means known in the art.

The transceiver 630 is operatively coupled with the processor 610, and transmits and/or receives wireless signals. The transceiver 630 includes a transmitter and a receiver. The transmitting and receiving unit 630 may include a baseband circuit for processing radio frequency signals. The transmitting and receiving unit controls one or more antennas 631 to transmit and/or receive wireless signals.

The speaker 640 outputs sound-related results processed by the processor 610. The microphone 641 receives sound-related inputs to be used by the processor 610.

In the case of the transmitting device, the processor 610 transmits the first data to the first STA during the first duration through the first band, and transmits the second data to the second STA while the first data is being transmitted to the second band And perform power saving in the second band for the first STA during the first duration.

In the case of a receiving device, the processor 610 receives the first data from the AP during the first duration through the first band, and while the first data is being transmitted, the second data from the AP to the second STA Is received on the second band, and performs power saving in the second band during the first duration.

The first band and the second band are aggregated with each other in a multi-band. The first band includes a first primary channel, and the second band includes a second primary channel.

If the multiple bands are combined into only two bands, the first band may be a 2.4 GHz or 5 GHz band, and the second band may be a 6 GHz band. If the third band of the multi-band is further combined, the first band may be the 2.4 GHz band, the second band may be the 5 GHz band, and the third band may be the 6 GHz band. However, the configuration of the above-described band is only an example, and the wireless LAN system may support various numbers of bands and channels.

The multi-band supports DL transmission and UL transmission at the same time. This is called FDU (Flexible DL/UL) transmission. FDU transmission is a transmission technique that can increase TSS/Rx average throughput by simultaneously enabling Tx/Rx transmission in multiple bands.

The first STA is switched to a doze state in the second band during the first duration. That is, the first STA receives the first data (or first PPDU) in the first band, but the second STA receives the second data (or second PPDU) in the second band for the same time. Therefore, the first STA may perform power saving for the second band. During the first duration, since the second STA is receiving the second data in the second band, the first STA cannot use the channel of the second band during the corresponding time. The first STA may switch to a doze state for the second band during the first duration.

Further, the AP may transmit third data to the first STA during the second duration through the first band. When the channel of the second band is BUSY during the second duration, the AP may perform the power saving in the second band for the first STA. In this case, the first STA may be switched to the doze state in the second band during the second duration. That is, since the channel of the second band is BUSY during the second duration, the first STA cannot use the channel of the second band during the corresponding time. Accordingly, the first STA may switch to the doze state for the second band during the first duration.

In addition, the AP may transmit the fourth data to the first STA during the third duration through the second band. When there is no data to be transmitted in the first band during the third duration, the AP may perform the power saving in the first band for the first STA. The first STA may switch to a doze state in the first band during the third duration. That is, since there is no data to be transmitted in the first band during the third duration, the first STA does not use the channel of the first band during the corresponding time. Accordingly, the first STA may switch to the doze state for the first band during the third duration.

Also, the fourth data may include information that there is no data to be transmitted in the first band during the third duration. Accordingly, the first STA can know that there is no data transmission in the first band until the transmission of the fourth data is transmitted in the second band, until the transmission of the fourth data ends (the Power saving).

Each of the multi-bands can also be applied to the TDD technique. Accordingly, accordingly, the first and second data are transmitted during the first duration, the third data is transmitted during the second duration, and the fourth data is transmitted during the third duration. However, the first to third durations do not overlap in the time domain. That is, the first to third durations may be distinguished from each other in different sections in a time domain by applying a TDD technique to the multiple bands. Accordingly, the first duration, the second duration, and the third duration may be time intervals sequentially transmitted.

The power saving includes power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state It can be power saving.

The first and third data may include first information on power saving in the second band, and the fourth data may include second information on power saving in the first band.

The first information may be included in a signal field or MAC frame of the first and third data, and the second information may be included in a signal field or MAC frame of the fourth data.

The fourth data may include third information about whether there is data to be transmitted in the first band. The third information may be set as one bit. For example, if there is data to be transmitted in the first band (specific band), the bit may be set to 1, and if there is no data to be transmitted in the first band, the bit may be set to 0.

The first band and the second band may represent channels. Accordingly, the first band may be a primary channel of a specific band, and the second band may be a secondary channel of a specific band.

In addition, the first band may be a band including a primary channel, and the second band may be a band including a secondary channel.

Hereinafter, a signaling method for multi-band aggregation will be described. In this embodiment, it has been described as receiving configuration information for multiple bands, and signaling may be performed by using the FST configuration method.

The transmitting device and the receiving device described below may be the aforementioned AP or the first and second STAs. The transmitting device may transmit a multi-band setting request frame to the receiving device. The transmitting device may receive a multi-band setting response frame from the receiving device.

The transmitting device may transmit a multi-band Ack request frame to the receiving device. The transmitting device may receive a multi-band Ack response frame from the receiving device.

The transmitting device may include a first Station Management Entity (SME), a first MAC Layer Management Entity (MLME), and a second MLME. The receiving device may include a second SME, a third MLME, and a fourth MLME.

The first MLME and the third MLME are entities supporting the first band, and the second MLME and the fourth MLME may be entities supporting the second band.

The multi-band setup request frame and the multi-band setup response frame may be transmitted and received between the first MLME and the third MLME. The multi-band Ack request frame and the multi-band Ack response frame may be transmitted and received between the second MLME and the fourth MLME.

The first and second SME may generate primitives including multi-band parameters. The multi-band parameter may include a channel number designated in the multi-band, an operating class, and a band ID (identifier). The primitive may be delivered to the first to fourth MLME.

When the multi-band method borrows the FST setting method, it includes four states, and is composed of rules for a method of moving from one state to the next. The four states are Initial, Setup Completed, Transition Done and Transition Confirmed.

In the Initial state, the transmitting device and the receiving device communicate in an old band/channel. At this time, when the FST setup request frame and the FST setup response frame are transmitted and received between the transmitting apparatus and the receiving apparatus, the system moves to a Setup Complete state, and the transmitting apparatus and the receiving apparatus are ready to change the currently operating band/channel(s). do. The FST session may be delivered in whole or in part to other bands/channels.

When the value of the LLT included in the FST setup request frame is 0, it moves from the Setup Complete state to the Transition Done state, and allows the transmitting device and the receiving device to operate in different bands/channels.

Both the transmitting and receiving devices must successfully communicate in a new band/channel to reach the Transition Confirmed state. At this time, when the FST Ack request frame and the FST Ack response frame are transmitted and received between the transmitting device and the receiving device, the device moves to a Transition Confirmed state, and the transmitting device and the receiving device form a complete connection in a new band/channel.

Claims (17)

1. In a method for performing power saving (power saving) in a wireless LAN system,

   An AP (Access Point) transmitting the first data to the first STA (Station) during the first duration through the first band;

   The AP transmitting second data to a second STA through a second band while the first data is transmitted; And

   The AP comprises performing power saving in the second band for the first STA during the first duration,

   The first band and the second band are aggregated with each other in a multi-band,

   The first STA is switched to a doze state in the second band during the first duration

   Way.
2. According to claim 1,

   The AP transmitting third data to the first STA during a second duration through the first band; And

   When the channel of the second band is BUSY during the second duration, the AP further includes performing the power saving in the second band for the first STA,

   The first STA is switched to the doze state in the second band during the second duration

   Way.
3. According to claim 2,

   The AP transmitting the fourth data to the first STA during the third duration through the second band; And

   When there is no data to be transmitted in the first band during the third duration, the AP further includes performing the power saving in the first band for the first STA,

   The first STA is switched to the doze state in the first band during the third duration

   Way.
4. According to claim 3,

   The first to third durations do not overlap in the time domain

   Way.
5. According to claim 3,

   The fourth data includes information that there is no data to be transmitted in the first band during the third duration.

   Way.
6. According to claim 3,

   The power saving is power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state Power Saving Inn

   Way.
7. According to claim 3,

   The first and third data include first information about power saving in the second band,

   The fourth data includes second information about power saving in the first band,

   The first information is included in a signal field or a MAC frame of the first and third data,

   The second information is included in the signal field or the MAC frame of the fourth data

   Way.
8. According to claim 3,

   The fourth data includes third information about whether data to be transmitted is present in the first band,

   The third information is set as one bit

   Way.
9. In an AP (Access Point) for performing power saving in a wireless LAN system, the AP,

   Memory;

   Transceiver; And

   A processor operatively coupled to the memory and the transceiver, the processor comprising:

   An AP (Access Point) transmitting the first data to the first STA (Station) during the first duration through the first band;

   The AP transmitting second data to a second STA through a second band while the first data is transmitted; And

   The AP comprises performing power saving in the second band for the first STA during the first duration,

   The first band and the second band are aggregated with each other in a multi-band,

   The first STA is switched to a doze state in the second band during the first duration

   Wireless devices.
10. The method of claim 9,

    The processor transmits third data to the first STA during a second duration through the first band; And

    When the channel of the second band is BUSY during the second duration, the processor performs the power saving in the second band for the first STA,

    The first STA is switched to the doze state in the second band during the second duration

    Wireless devices.
11. The method of claim 10,

    The processor transmits fourth data to the first STA during the third duration through the second band; And

    If there is no data to be transmitted in the first band during the third duration, the processor performs the power saving in the first band for the first STA,

    The first STA is switched to the doze state in the first band during the third duration

    Wireless devices.
12. The method of claim 11,

    The first to third durations do not overlap in the time domain

    Wireless devices.
13. The method of claim 11,

    The fourth data includes information that there is no data to be transmitted in the first band during the third duration.

    Wireless devices.
14. The method of claim 11,

    The power saving includes power saving in a baseband layer, radio frequency (RF) power saving in a channel of the first band, power saving for carrier sensing, or maintaining the dose state Power Saving Inn

    Wireless devices.
15. The method of claim 11,

    The first and third data include first information about power saving in the second band,

    The fourth data includes second information about power saving in the first band,

    The first information is included in a signal field or a MAC frame of the first and third data,

    The second information is included in the signal field or the MAC frame of the fourth data

    Wireless devices.
16. The method of claim 11,

    The fourth data includes third information about whether data to be transmitted is present in the first band,

    The third information is set as one bit

    Wireless devices.
17. In a method for performing power saving (power saving) in a wireless LAN system,

    The first STA (Station) receives the first data from the AP (Access Point) through the first band during the first duration, while the first data is transmitted to the second STA from the AP to the second STA Wherein data is received over the second band; And

    The first STA, the step of performing power saving in the second band during the first duration,

    The first band and the second band are aggregated with each other in a multi-band,

    The first STA is switched to a doze state in the second band during the first duration

    Way.

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