Patent Description:
In a wireless local area network (WLAN), a single basic service set (BSS) is composed of two kinds of entities which are a single AP Station (STA) and multiple non-AP STAs. STAs share a same radio frequency channel with one out of WLAN operation bandwidth options (e.g.<NUM>/<NUM>/<NUM>/<NUM>). Here, AP STA and non-AP STA could be referred as AP and STA, respectively.

the legacy IEEE <NUM>. 11a/b/g/n/ac standard does not guarantee communication stability in dense environments with many users. In order to overcome this limit, the High-Efficiency WLAN Study Group (HEW SG) and the IEEE Task Group ax (TGax) were formed by IEEE <NUM> working group, which has worked on the standardization of IEEE <NUM>. 11ax as the next generation WLAN standard in <NUM>. The IEEE <NUM>. 11ax standard aims to improve system throughput in dense environments with many APs and STAs. <CIT> discloses a full duplex mechanism to improve spectral efficiency of wireless communication systems such as <NUM>.

<CIT> discloses full-duplex communication over WLAN networks (HE WLAN, <NUM>. The AP obtains the channel through contention and computes a schedule for uplink and downlink transmissions for different stations in full duplex mode. The scheduling is either for two legacy stations, one that receives and one that sends at the same time, or for a single full-duplex station. The scheduling information is sent to the stations using a trigger frame with a legacy preamble.

Full-duplex (FD) communication is one of promising next-generation wireless technologies. This technology enables up to double network throughput ideally because the information can be transmitted and received between wireless communication nodes through the same channel at the same time. In recent FD communication becomes more feasible thanks to the enhancement of self-interference cancellation (SIC) technology.

The following description is intended to provide full-duplex communication between an AP and an STA in an IEEE <NUM>. 11ax environment.

Embodiments are defined by dependent claims.

The following description enables full-duplex communication in the IEEE <NUM>. 11ax environment while maintaining backward compatibility with the IEEE <NUM> standards (<NUM>. 11a/b/g/n/ac/ax). The following description provides a communication protocol for avoiding interference between an uplink signal and a downlink signal that are carried through the same channel at the same time in IEEE <NUM>.

Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness.

The presently described examples will be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The drawings are not necessarily drawn to scale, and the size and relative sizes of the layers and regions may have been exaggerated for clarity.

It will be understood that, although the terms first, second, A, B, etc. may be used herein to describe various elements, these elements should not be limited by these terms.

It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Before starting detailed explanations of figures, components that will be described in the specification are discriminated merely according to functions mainly performed by the components or conventionally carried out according to common knowledge of related technical fields. That is, two or more components which will be described later can be integrated into a single component. Furthermore, a single component which will be explained later can be separated into two or more components. Moreover, each component which will be described can additionally perform some or all of a function executed by another component in addition to the main function thereof. Some or all of the main function of each component which will be explained can be carried out by another component. Accordingly, presence/absence of each component which will be described throughout the specification should be functionally interpreted.

The following description applies to a wireless local area network (WLAN). The following description may apply to the next generation WLAN method (IEEE <NUM>. 11ax) or the like. The IEEE <NUM>. 11ax maintains compatibility with the conventional IEEE <NUM>. 11a/b/g/n/ac. The following description may be executed in the IEEE <NUM>. 11ax environment, and also maintains compatibility with the conventional IEEE <NUM>. 11a/b/g/n/ac.

The following description relates to in-band full-duplex communication. The following description may basically apply to the IEEE <NUM>. However, the following description does not necessarily limitedly apply to the IEEE <NUM>. Therefore, the following description may apply to WLAN standards that will emerge after the IEEE <NUM>.

A WLAN or a next generation WLAN basically refers to a communication network operating according to a protocol defined in the IEEE <NUM>. A conventional WLAN refers to a WLAN according to a standard prior to the IEEE <NUM>.

An access point (AP) is an apparatus that provides access to the distribution system services and mostly is connected to the Internet to provide a wireless channel in a certain coverage area. The apparatus is hereinafter referred to as an AP station or an AP.

A non-AP station (STA) is an apparatus that communicates the information through a certain wireless channel allocated by an AP. The apparatus is hereinafter referred to as a station or an STA.

A signal transmitted by an AP to an STA is called a downlink signal. The downlink signal may be composed of at least one frame. The frame included in the downlink signal is called a downlink frame.

A signal transmitted by an STA to an AP is called an uplink signal. The uplink signal may be composed of at least one frame. The frame included in the uplink signal is called an uplink frame.

The full-duplex communication basically refers to in-band full-duplex transmission and reception concurrently using the same channel.

The IEEE <NUM>. 11ax is well known as High Efficiency WLAN (HE WLAN). A Physical Protocol Data Unit (PPDU) is newly defined in the IEEE <NUM>. Examples of the PHY PPDU for data transmission include High Efficiency Single User Physical Protocol Data Unit (HE SU PPDU), High Efficiency Multi User Physical Protocol Data Unit (HE MU PPDU), High Efficiency extended range Single User Physical Protocol Data Unit (HE ER SU PPDU) and High Efficiency Trigger Based Physical Protocol Data Unit (HE TB PPDU).

First, the WLAN and the IEEE <NUM>. 11ax will be described briefly below.

<FIG> illustrates an example basic service set (BSS) in a wireless local area network (WLAN). A BSS may include one AP and at least one STA. <FIG> illustrates an example of a WLAN BSS <NUM> including a single AP <NUM> and a plurality of STAs <NUM>. For convenience of description, it is assumed that a single BSS includes a plurality of STAs. Any one of the plurality of STAs <NUM> receives resources allocated for wireless communication and communicates with the AP <NUM>. The AP <NUM> delivers information regarding the resource allocation to the STA.

<FIG> illustrates example resources used for WLAN communication. In <FIG>, one rectangular block refers to a resource allocated to one STA.

<FIG> illustrates Orthogonal Frequency Division Multiple (OFDM) used in the conventional IEEE <NUM>. A conventional WLAN has a frame exchange performed in Time Division Multiple Access (TDMA). STAs share any one wireless frequency channel in ISM band. Only one user (STA) occupies a specific channel in a specific time period.

<FIG> illustrates Orthogonal Frequency Division Multiple Access (OFDMA) modulation technology was employed newly in the IEEE <NUM>. In OFDMA, one wireless channel can be composed of one or multiple resource units and the IEEE <NUM>. 11ax defines RU as a minimum allocation unit which is a group of subcarriers. The OFDMA enables multi-user transmission using frequency orthogonal division in the same time period. Any one user (STA) may use one RU in a specific time period. The AP may allocate different RUs to one or a plurality of STAs in a WLAN packet. Alternatively, the AP may separate spatial streams in a specific RU to allocate resources to any one or a plurality of STAs. The OFDMA provides more dynamic resource allocation to multiple users than the OFDM.

<FIG> illustrates an example PHY PPDU packet format newly defined in <NUM>. The PPDUs in <FIG> are as follows: HE SU PPDU; HE MU PPDU; HE ER SU PPDU; and HE TB PPDU. The formats are shown in <FIG>. Details of fields constituting each of the formats shown in <FIG> are shown in Table <NUM> below. Detailed descriptions of the fields will be omitted. The HE TB PPDU will be described below with reference to <FIG>.

<FIG> illustrates an example communication process between an AP and multiple STAs in <NUM>. <FIG> illustrates an example communication process in a BSS in which there are a single AP and 'n' number of STAs. This example will be described in time order. <FIG> describes a multi-user (MU) scenario as an example.

The AP transmits a Multi-User Request-to-Send (MU-RTS) frame to STA <NUM> and STA n at time T = t0. In response to the MU-RTS frame, STA <NUM> and STA n commence a Clear-to-Send (CTS) frame at time T = t1. After receiving the CTS response successfully, the AP can perform the following steps. The MU-RTS/CTS exchange corresponds to a pre-operation for WLAN data transmission. This process is optional, and thus may not be an operation that must be performed before a DL MU PPDU.

The AP transmits a frame including resource allocation information to solicited STAs. The AP transmits a DL MU PPDU to solicited STAs, herein, STA <NUM> and STA n at time T = t2. The DL MU PPDU may include a trigger frame or the DL MU PPDU may include a triggered response scheduling (TRS) control field. In response to the DL MU PPDU, STA <NUM> and STA n transmit an HE TB PPDU at time T = t3 as a response frame along with an ACK. The solicited STAs transmit the HE TB PPDU using allocated RU respectively.

The AP may transmit a BlockAck frame in response to the reception of the HE TB PPDU. This kind of transmission of the BlockAck frame may be optional.

By repeating the above communication process, the AP may communicate with a plurality of STAs.

Full-duplex communication applicable to a WLAN environment such as <NUM>. 11ax will be described below. It is assumed that an AP and STA which will be mentioned support IEEE <NUM>.

<FIG> illustrates an example process of performing full-duplex communication in a WLAN environment. <FIG> illustrates a BSS <NUM> that performs full-duplex communication in a WLAN environment. The BSS <NUM> includes a single AP <NUM> and n number of STAs <NUM>-<NUM>, <NUM>-<NUM>,. The AP <NUM> is an AP capable of full-duplex communication (hereinafter referred to as an FD-capable AP). The FD-capable AP may be an AP having a function of cancelling self-interference (SI) caused by a signal transmitted by the AP itself. The SI cancellation technology can be implemented in various ways.

<FIG> illustrates an example for a full-duplex communication in the BSS <NUM>. This example will be described in time order. The AP <NUM> transmits a reference frame to STA <NUM><NUM>-<NUM> and STA n <NUM>-n. The reference frame may be the above-described trigger frame. Also, the reference frame may include a TRS control field. The reference frame may include RU allocation information for OFDMA communication.

When the reference frame is received, solicited STA <NUM><NUM>-<NUM> and STA n <NUM>-n transmit an HE TB PPDU through allocated RUs. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU to the AP in the same time period. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU at a certain timing on the basis of the received reference frame. That is, STA <NUM><NUM>-<NUM> and STA n <NUM>-n may synchronize frames to be transmitted by using the timing of the received reference frame end.

Meanwhile, the AP <NUM> may transmit a certain frame to STA <NUM><NUM>-<NUM> at or within the same time period in which STA <NUM><NUM>-<NUM> and STA n <NUM>-n transmit an HE TB PPDU. Herein the frame transmitted from the AP <NUM> is represented as an HE TB FD PPDU. That is, the AP <NUM> transmits a frame to STA <NUM><NUM>-<NUM> while receiving frames from STA <NUM><NUM>-<NUM> and STA n <NUM>-n in the same time period (full-duplex communication). In <FIG>, a downlink constituting the full-duplex communication is represented by a thick solid line. The AP <NUM> synchronizes downlink and uplink and then performs downlink transmission. The AP <NUM> transmits an HE TB FD PPDU on the basis of the reference frame transmitted by the AP <NUM> or on the basis of timing information included in the reference frame.

<FIG> illustrates another example process of performing full-duplex communication in a WLAN environment. <FIG> may be an example process of the BSS of <FIG>. This example will be described in time order.

The AP <NUM> transmits an MU-RTS frame to STA <NUM><NUM>-<NUM> and STA n <NUM>-n at time T = t0. In response to the MU-RTS frame, STA <NUM><NUM>-<NUM> and STA n <NUM>-n commence the transmission of a CTS frame at time T = t1 respectively in OFDMA modulation way. After receiving the CTS response, the AP can perform the following steps. The MU-RTS/CTS exchange corresponds to a pre-operation for MU transmission. This process is optional, and thus may not be an operation that must be performed before the DL MU PPDU.

The AP <NUM> transmits the DL MU PPDU to STA <NUM><NUM>-<NUM> and STA n <NUM>-n at time T = t2. The DL MU PPDU corresponds to the above-described reference frame. The DL MU PPDU may include a TRS control field. The DL MU PPDU may include RU allocation information for STAs. When the reference frame is received, STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU through allocated RUs along with an ACK at time T = t3. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU to the AP in the same time period. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU at a certain timing which is the SIFS time boundary, after the end of a received reference frame. That is, STA <NUM><NUM>-<NUM> and STA n <NUM>-n may synchronize frames to be transmitted by using the received DL MU PPDU. A SIFS is the time from the end of the last symbol, or signal extension if present, of the previous frame to the beginning of the first symbol of the preamble of the subsequent frame. For example, if the control frame is a response frame of a previous frame, the WLAN device transmits the control frame without performing backoff if a SIFS has elapsed.

Meanwhile, the AP <NUM> may transmit an HE TB FD PPDU to STA <NUM><NUM>-<NUM> at time T = t3. That is, the AP <NUM> transmits a frame to STA <NUM><NUM>-<NUM> while receiving frames from STA <NUM><NUM>-<NUM> and STA n <NUM>-n in the same time period (full-duplex communication). The AP <NUM> transmits an HE TB FD PPDU on the basis of the DL MU PPDU transmitted by the AP <NUM> or on the basis of timing information included in the DL MU PPDU. Referring to <FIG>, a null portion are shown in front of the HE TB FD PPDU at time T = t3. This will be described with <FIG>.

In response to the reception of the HE TB PPDU, the AP <NUM> may transmit a BlockAck frame to STA <NUM><NUM>-<NUM> and STA n <NUM>-n at time T = t4. The transmission of the BlockAck frame may be optional. Also, at time T = t4, STA <NUM><NUM>-<NUM> may transmit an ACK for the HE TB FD PPDU corresponding to time T = t3.

<FIG> is still another example process of performing full-duplex communication in a WLAN environment. <FIG> illustrates a BSS <NUM> that performs full-duplex communication in a WLAN environment. The BSS <NUM> includes a single AP <NUM> and n STAs <NUM>-<NUM>, <NUM>-<NUM>,. The AP <NUM> is an AP capable of full-duplex communication (hereinafter referred to as an FD-capable AP). The FD-capable AP may be an AP having a function of cancelling self-interference (SI) caused by a signal transmitted by the AP itself. STA <NUM><NUM>-<NUM> and STA n <NUM>-n are STAs capable of full-duplex communication. The FD-capable STA may be an STA having a function of cancelling self-interference (SI) caused by a signal transmitted by the STA itself. The SI cancellation technology can be implemented in various ways.

<FIG> illustrates an example in which full-duplex communication is performed in the BSS <NUM>. This example will be described in time order. The AP <NUM> transmits a reference frame to STA <NUM><NUM>-<NUM> and STA n <NUM>-n. The reference frame may be the above-described trigger frame. Also, the reference frame may include a TRS control field. The reference frame may include RU allocation information for OFDMA communication.

When the reference frame is received, STA <NUM><NUM>-<NUM> and STA n <NUM>-n transmit an HE TB PPDU through allocated RUs. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may each transmit an HE TB PPDU to the AP in the same time period. STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an HE TB PPDU at a certain timing on the basis of the received reference frame. That is, STA <NUM><NUM>-<NUM> and STA n <NUM>-n may synchronize frames to be transmitted by using the received reference frame.

Meanwhile, the AP <NUM> may transmit an HE TB FD PPDU to STA <NUM><NUM>-<NUM> and STA n <NUM>-n at or within a time period in which the HE TB PPDU is received (full-duplex communication). In <FIG>, a downlink constituting the full-duplex communication is represented by a thick solid line. The AP <NUM> synchronizes downlink and uplink and then performs downlink transmission. The AP <NUM> transmits an HE TB FD PPDU on the basis of the reference frame transmitted by the AP <NUM> or on the basis of timing information included in the reference frame.

Similarly, to <FIG>, although not shown in <FIG>, the MU-RTS/CTS exchange may be performed before the reference frame is transmitted. Also, after the HE TB FD PPDU is transmitted, the AP <NUM> may transmit a BlockAck frame in response to the reception of the HE TB PPDU. Also, STA <NUM><NUM>-<NUM> and STA n <NUM>-n may transmit an ACK for the HE TB FD PPDU.

<FIG> is an example packet for full-duplex communication. An HE TB PPDU structure defined in IEEE <NUM>. 11ax is shown in an upper portion of <FIG>. An example HE TB FD PPDU structure is shown in a lower portion of <FIG>. An example in which the HE TB PPDU and the HE TB FD PPDU are placed in the same time period is shown. <FIG> is an example in which HE TB PPDU (uplink) and HE TB FD PPDU (downlink) constituting full-duplex communication are placed in the same time period.

As described above, the HE TB PPDU may be transmitted in a certain time period on the basis of a reference frame (trigger framing) sent by AP. In this case, the HE TB PPDU may be transmitted after a short IFS (SIFS) time interval from the reference frame end. The SIFS refers to the shortest one among inter-packet space time intervals between consecutive two packets defined in the standard.

The HE TB PPDU can be divided into a non-HE portion and an HE portion. The non-HE portion includes a L-short training field (STF), L-long training field (LTF), and L-signal information field (SIG). These fields are defined in a conventional WLAN standard. 11ax uses the same fields as described in the WLAN standard for the purpose of compatibility with conventional WLAN. The L-STF is a short training sequence and is used for packet detection and automatic gain adjustment (AGC). The L-LTF is a relatively long training sequence and is used for channel estimation. The L-SIG may include control information corresponding to decoding of PSDU or the like.

RL-SIG, in which a conventional legacy L-SIG is repeated, is a field for HE PPDU detection. HE-SIG-A includes MCS, a frequency bandwidth, the number of spatial streams (NSTS), and parameters for frame decoding. HE-STF and HE-LTF include a training sequence for multiple-input and multiple-output (MIMO). The HE-STF is mainly used to measure automatic gain adjustment during MIMO transmission. The HE-LTF is used to estimate a MIMO channel. The HE-LTF has a variable length. Data field includes an encoder/decoder scrambler and an encoded MAC frame. PE is an extension field.

The HE TB PPDU can be divided into a pre-HE modulated field and an HE modulated field. HE PHY can support DFT periods of <NUM> and <NUM> for the pre-HE modulated field and the HE modulated filed of the HE PPDU, respectively.

In the HE TB FD PPDU, a modulated signal may be transmitted in a region in which the HE modulated field of the HE TB PPDU is started in the same time period. The HE TB FD PPDU may be aligned to the HE modulated field of the HE TB PPDU in the same time period. A null portion may be a signal field in which no signal is transmitted. Also, the null portion may be a signal field for transmitting information that does not affect the demodulation processing of the HE TB PPDU by the AP. The HE TB FD PPDU may be transmitted in a time period in which the AP receives the HE TB PPDU, and the HE TB FD PPDU is intended to be transmitted in a period that does not affect the processing of the received HE TB PPDU. That is, the AP controls a time to transmit the HE TB FD PPDU such that the transmission of the HE TB FD PPDU does not disturb the transmission of the HE TB PPDU. The AP ensures that the training process for the received HE TB PPDU is normally performed.

A lower portion of <FIG> illustrates an HE TB FD PPDU structure. The HE TB FD PPDU structure shown in <FIG> is an example, and the HE TB FD PPDU may have another structure. <FIG> illustrates an example including FD-STF, FD-LTF, FD-SIG, and the like. In this case, the fields may perform functions similar to those of the HE-STF, HE-LTF, and HE-SIG.

<FIG> illustrates example resources to be allocated for full-duplex communication. <FIG> illustrates an example in which individual RUs are allocated to uplink and downlink. As described in <FIG>, when an FD-capable AP performs full-duplex communication with any STA, the AP and the STA may use different RUs.

<FIG> illustrates an example in which a common RU is allocated to uplink and downlink. <FIG> illustrates a case in which a pair of AP and STA uses a single common RU. As shown in <FIG>, when an FD-capable AP and an FD-capable STA perform full-duplex communication, the pair may use a common RU. The AP may deliver information regarding the RU through the reference frame (the trigger frame). <FIG> illustrates an example in which the AP of <FIG> and STA <NUM> use a common RU and the AP of <FIG> and STA n use a common RU.

<FIG> illustrates an example of resource allocation for full-duplex communication. <FIG> illustrates an example in which an AP receives an HE TB PPDU from two STAs (STA <NUM> and STA n) at a specific time and transmits an HE TB FD PPDU to an STA (STA1, STA n, or another STA) at the same specific time. <FIG> illustrates a <NUM>-MHz band, as an example.

<FIG> illustrates an example of resource allocation for the HE TB PPDU transmitted by STA <NUM>. <FIG> illustrates an example of resource allocation for the HE TB FD PPDU transmitted by the AP. In the HE TB FD PPDU, a signal is transmitted only in the HE modulated field as described above. <FIG> illustrates an example of resource allocation for the HE TB PPDU transmitted by STA n. <FIG> illustrates an example in which resources are allocated to frames transmitted by STA <NUM>, STA n, and the AP in the same time period. Referring to <FIG>, it shows that three individual frames may be simultaneously transmitted on two channels of <NUM>.

When <NUM>-tone RU (<NUM>) or less-tone RU is allocated, a pre-HE modulated field is generally transmitted at corresponding <NUM> (indicated by ① and ② in <FIG>). However, in some cases, the pre-HE modulated field may be transmitted at <NUM> including a corresponding <NUM> channel (not shown).

<FIG> illustrates an example reference frame. The reference frame may be a trigger frame defined in IEEE <NUM>. The reference frame may include information regarding RUs for full-duplex communication (FD). Resource allocation information for the FD communication may be implemented in various ways. <FIG> illustrates an example frame to be used in <NUM>. A description of information included in a MAC header, that is, a description of the same part as a conventional WLAN header will be omitted.

HT Control includes an aggregated control subfield. In <FIG>, a part (A) indicates an example in which a field for FD resource information is separately added to the control subfield. The part (A) includes Control ID, FD, and Reserved field. Control ID is an identifier about information indicated by the control subfield. When Control ID is configured to set a value indicating FD resource information, FD field may include resource information for the FD communication. In <FIG>, a part (B) indicates another example control subfield. In the part (B), when Control ID is configured to set a value indicating FD resource information, the resource information for the FD may be included in Control Information field. Alternatively, when Control ID is a specific value to which any current use is not allocated, the resource information for the FD feature may be included in Control Information field.

<FIG> illustrates an example in which the FD resource information is conveyed using HT Control field. In some cases, the reference frame may convey the FD resource information through another field or an FD-dedicated field.

<FIG> illustrates an example block diagram of an AP and an STA. <FIG> illustrates a BSS including a single AP <NUM> and a single STA <NUM>, as an example. It is assumed that the AP <NUM> and the STA <NUM> are FD-capable apparatuses.

The AP <NUM> includes a storage device <NUM>, a memory <NUM>, a computing device <NUM>, and a communication device <NUM>. In <FIG>, the storage device <NUM>, the memory <NUM>, the computing device <NUM>, and the communication device <NUM> are shown as separate independent elements. At least any combination merged with two or more components among the storage device, the memory, the computing device and the communication device <NUM> may be configured in an integrated manner.

The storage device <NUM> stores a source code or program for WLAN communication with the STA. The storage device <NUM> stores information for high-efficiency WLAN communication by default. Also, the storage device <NUM> may store information for the above-described full-duplex communication. The storage device <NUM> may be implemented in the form of a hard disk, a read-only memory (ROM), a flash memory, or the like. The storage device <NUM> may store data to be transmitted and data received.

The memory <NUM> may temporarily store data generated while the AP <NUM> performs communication.

The communication device <NUM> refers to an element for transmitting and receiving data through WLAN communication. The communication device <NUM> may include at least one antenna and a communication module. The communication device <NUM> may include a plurality of antennas for MIMO. The communication device <NUM> may receive packets from at least one STA. Also, the communication device <NUM> may transmit packets to at least one STA. The communication device <NUM> may receive program update information from an external object.

The computing device <NUM> may transmit and receive data (packets) using a program stored in the storage device <NUM>. The computing device <NUM> may transmit a reference frame to at least one STA through the communication device <NUM> according to a received command or a generated command. The communication device <NUM> may receive an uplink frame from an STA in a specific time period determined on the basis of the reference frame. The computing device <NUM> may transmit a downlink frame to an STA through the communication device <NUM> in a part time of the time period in which the downlink frame is received. In this case, the computing device <NUM> may transmit a downlink frame to the STA having transmitted the uplink or another STA. In this case, the computing device <NUM> may perform control such that the downlink frame is transmitted to an HE modulated field of an uplink frame. The computing device <NUM> may be a device for processing data and performing certain computation, such as a processor, an AP, and a chip with an embedded program.

For example, the AP <NUM> may transmit the DL MU PPDU to the STA <NUM>. The AP <NUM> may receive the HE TB PPDU from the STA <NUM> in a specific time period. In this case, the AP <NUM> may transmit the HE TB FD PPDU to the STA <NUM> or another STA in a period in which an HE TB PPDU HE modulated field is transmitted.

Although not shown in <FIG>, the AP <NUM> may include an element for cancelling SI to perform full-duplex communication.

The STA <NUM> includes a storage device <NUM>, a memory <NUM>, a computing device <NUM>, an interface device <NUM>, and a communication device <NUM>. In <FIG>, the storage device <NUM>, the memory <NUM>, the computing device <NUM>, the interface device <NUM>, and the communication device <NUM> are shown as separate independent elements. At least any combination merged with two or more components among the storage device <NUM>, the memory <NUM>, the computing device <NUM>, the interface device <NUM> and the communication device <NUM> may be configured in an integrated manner.

The storage device <NUM> stores a source code or program for WLAN communication with the AP. The storage device <NUM> stores information for high-efficiency WLAN communication by default. Also, the storage device <NUM> may store information for the above-described full-duplex communication. The storage device <NUM> may be implemented in the form of a hard disk, a ROM, a flash memory, or the like. The storage device <NUM> may store data to be transmitted and data received.

The memory <NUM> may temporarily store data generated while the STA <NUM> performs communication.

The interface device <NUM> is a device for receiving certain commands or data from the outside. The interface device <NUM> may receive certain commands or data from an external storage device or an input device that is physically connected to the interface device <NUM>. The interface device <NUM> may receive a command for communication with the AP <NUM>, control information, data to be transmitted, or the like.

The communication device <NUM> refers to an element for transmitting and receiving data through WLAN communication. The communication device <NUM> may include at least one antenna and a communication module. The communication device <NUM> may include a plurality of antennas for MIMO. The communication device <NUM> may receive packets from the AP. Also, the communication device <NUM> may transmit packets to the AP. The communication device <NUM> may receive program update information from an external object.

The computing device <NUM> may transmit and receive data (packets) using a program stored in the storage device <NUM>. The communication device <NUM> may receive a reference frame from the AP <NUM>. The computing device <NUM> may determine a specific time period on the time basis of the reference frame. The computing device <NUM> may transmit an uplink frame to the AP through the communication device <NUM> in the determined specific time period. The computing device <NUM> may be a device for processing data and performing certain computation, such as a processor, an AP, and a chip with an embedded program.

The communication device <NUM> may receive a downlink frame from the AP <NUM> in a part time of the period in which the uplink frame is transmitted. In this case, the downlink frame may be received in a region where an HE modulated field of the uplink frame is placed. The computing device <NUM> may control the communication device <NUM> such that the downlink frame is received at the same time as the uplink frame is transmitted.

For example, the STA <NUM> may receive the DL MU PPDU from the AP <NUM>. The STA <NUM> may transmit the HE TB PPDU in a specific time period on the basis of the DL MU PPDU. The STA <NUM> may receive the HE TB FD PPDU from the AP <NUM> while transmitting the HE TB PPDU. The HE TB FD PPDU may be received in a period in which the HE modulated field of the HE TB PPDU is transmitted.

Although not shown in <FIG>, the STA <NUM> may include an element for cancelling SI to perform full-duplex communication.

Also, the above-described full-duplex communication method may be implemented using a program (or application) including an executable algorithm that may be executed by a computer. The full-duplex communication method may be embedded into an AP and an STA.

The program may be stored and provided in a non-transitory computer readable medium. The non-transitory computer readable medium refers not to a medium that temporarily stores data such as a register, a cache, and a memory but to a medium that semi-permanently stores data and that is readable by a device. Specifically, the above-described various applications or programs may be provided while being stored in a non-transitory computer readable medium such as a compact disc (CD), a digital versatile disc (DVD), a hard disk, a Blu-ray disc, a Universal Serial Bus (USB), a memory card, a read-only memory (ROM), etc..

Claim 1:
A full-duplex communication method in a high efficiency wireless local area network (WLAN), the full-duplex communication method being performed by an access point (AP) in a WLAN network, the method comprising:
transmitting to at least one station (STA), a trigger frame including Resource Unit (RU) allocation information of an Orthogonal Frequency Division Multiple Access (OFDMA) communication;
receiving a High Efficiency Trigger Based Physical Protocol Data Unit (HE TB PPDU) from the at least one STA in a time period determined on the basis of the trigger frame through the allocated RU; and
transmitting a High Efficiency Trigger Based Full Duplex Physical Protocol Data Unit (HE TB FD PPDU) to the at least one STA in the time period,
wherein the HE TB PPDU and the HE TB FD PPDU are transmitted simultaneously,
wherein the HE TB FD PPDU includes a null portion including a signal field in which no signal is transmitted or including a signal field for transmitting information that does not affect the demodulation processing in the HE TB PPDU, and
wherein the HE TB PPDU is divided into a pre-HE modulated field and an HE modulated field, the pre-HE modulated field of the HE TB PPDU being aligned with the null portion of the HE TB FD PPDU, the pre-HE modulated field including a non-HE portion including a L-short training field STF and L-long training field LTF.