Apparatus and method for coordinated spatial reuse in wireless communication

Abstract

A method of wireless communication is provided. The method can be performed by a first apparatus and can include obtaining a transmit opportunity (TXOP) for transmitting a first physical layer protocol data unit (PPDU) with a first transmit power, limiting a second transmit power of a second apparatus to share the TXOP with the second apparatus, and transmitting the first PPDU to a third apparatus with the transmit power in the shared TXOP.

Description

[0001] Cross Reference to Related Applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2020-0107973, filed on August 26, 2020, to Korean Patent Application No. 10-2020-0124192, filed on September 24, 2020, and to Korean Patent Application No. 10-2021-0022600, filed on February 19, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0003] The present inventive concept relates to wireless communication, and particularly, to an apparatus and method for coordinated spatial reuse in wireless communication. BACKGROUND

[0004] Wireless communication is a method of transmitting information or data without using a wired connection. For example, a wireless local area network (WLAN) is a technology for connecting two or more devices to each other in a wireless signal transmission method. The WLAN technology is based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. The 802.11 standard has evolved to 802.11b, 802.11a, 802.11g, 802.11n, 802.11ac, 802.11ax, etc., and supports high transmission speeds based on orthogonal frequency division multiplexing (OFDM) technology.

[0005] In 802.11ac, data can be simultaneously transmitted to multiple users through a multi-user multiple input multiple output (MU-MIMO) method. In 802.11ax, which is referred to as high efficiency (HE), multiple access is achieved by dividing and providing available subcarriers to users through the adoption of orthogonal frequency division multiple access (OFDMA) as well as the MU-MIMO method. Accordingly, a WLAN system using 802.11ax supports communication in congested areas and outdoors.

[0006] In 802.11be, which is referred to as extremely high throughput (EHT), support for a 6 GHz band, bandwidth utilization of up to 320 MHz per channel, adoption of hybrid automatic repeat and request (HARQ), support for up to 16x16 MIMO, etc. are aimed at. Accordingly, it is expected that the next-generation WLAN system effectively supports low latency and super-high-speed transmission like new radio (NR) 5G technology. As a result, the efficiency of the current system is limited. Therefore, there is a need in the art to improve the throughput of a wireless communication system. SUMMARY

[0007] The present inventive concepts provide an apparatus and method for efficiently performing spatial reuse in wireless communication.

[0008] According to an aspect of the present inventive concepts, a wireless communication method performed by a first apparatus includes obtaining a transmit opportunity (TXOP) for transmitting a first physical layer protocol data unit (PPDU) with a first transmit power, determining a limit on a second transmit power of a second apparatus, sharing the TXOP with the second apparatus based at least in part on the determined limit on the second transmit power, and transmitting the first PPDU to a third apparatus with the first transmit power in the shared TXOP.

[0009] According to another aspect of the present inventive concepts, a first apparatus for wireless communication includes a transceiver and processing circuitry configured to obtain, by the transceiver, a TXOP for transmitting a first PPDU with a first transmit power, determine, by the transceiver, a limit on a second transmit power of a second apparatus, share, by the transceiver, the TXOP with the second apparatus based at least in part on the determined limit on the second transmit power, and transmit, by the transceiver, the first PPDU to at least one third apparatus in the shared TXOP.

[0010] According to another aspect of the present inventive concepts, a wireless communication method performed by a second apparatus that shares a TXOP with a first apparatus includes outputting a frame including capability information and first transmit power information, wherein the capability information indicates support for spatial reuse and the first transmit power information indicates a first transmit power of the frame, receiving second transmit power information from the first apparatus, and transmitting a PPDU to at least one third apparatus in the TXOP with a second transmit power that is equal to or lower than the first transmit power indicated by the first transmit power information.

[0011] According to another aspect of the present inventive concepts, a wireless communication method performed by a third apparatus that receives a PPDU in a TXOP shared by a first apparatus and a second apparatus includes determining a first path loss between the first apparatus and the third apparatus based on a first frame received from the first apparatus, determining a second path loss between the second apparatus and the third apparatus based on a second frame received from the second apparatus, transmitting information about the first path loss and the second path loss to the first apparatus, and receiving the PPDU from the first apparatus in the TXOP.

[0012] According to another aspect of the inventive concepts, there is a method for wireless communications at a first access point, the method comprising: determining at least one path loss comprising a path loss between a first station and the first access point, a path loss between a second station and a second access point, or both; identifying a first transmit power for transmitting a first physical layer protocol data unit (PPDU) to the first station during a shared transmit opportunity (TXOP) based at least in part on the determined at least one path loss; determining a transmit power limit for transmitting a second PPDU from the second access point to the second station based at least in part on the first transmit power and the shared TXOP; transmitting an indication of the transmit power limit to the second access point; and transmitting the first PPDU to the first station with the first transmit power based at least in part on transmitting the indication of the transmit power limit to the second access point. BRIEF DESCRIPTION OF DRAWINGS

[0013] Embodiments of the inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1 is a block diagram illustrating a wireless communication system according to an example embodiment;

[0015] Figure 2 is a block diagram illustrating a wireless communication system according to an example embodiment;

[0016] Figure 3 is a message diagram illustrating a method for coordinating spatial reuse according to an example embodiment;

[0017] Figure 4 is a block diagram illustrating a wireless communication system according to an example embodiment;

[0018] Figure 5 is a flow diagram illustrating a method for coordinating spatial reuse according to an example embodiment;

[0019] Figure 6 illustrates a beacon frame according to an example embodiment;

[0020] Figure 7 is a flow diagram illustrating a method for coordinating spatial reuse according to an example embodiment;

[0021] Figure 8 is a flow diagram illustrating a method for coordinating spatial reuse according to an example embodiment;

[0022] Figure 9A and 9B illustrates an example of an announcement frame according to an example embodiment;

[0023] Figure 10is a message diagram illustrating a method for coordinating spatial reuse according to example embodiments;

[0024] Figure 11 is a flow diagram illustrating a method for coordinating spatial reuse according to example embodiments;

[0025] Figure 12 is a timing diagram illustrating an example of transmissions based on coordinated spatial reuse according to example embodiments;

[0026] Figure 13 is a message diagram illustrating a method for coordinating spatial reuse according to example embodiments;

[0027] Figure 14 illustrates an announcement frame according to example embodiments;

[0028] Figure 15A and Figure 15B is a timing diagram illustrating an example of transmissions based on coordinated spatial reuse according to example embodiments;

[0029] Figure 16 is a block diagram illustrating a wireless communication system according to example embodiments; and

[0030] Figure 17 illustrates an example of an apparatus for wireless communication according to example embodiments. DETAILED DESCRIPTION

[0031] The present disclosure relates generally to wireless communications. More specifically, embodiments of the present disclosure relate to a method, apparatus, and system for coordinated spatial reuse (C-SR) in wireless communications, which can improve the throughput of a wireless communication system. Spatial reuse generally can include techniques for performing transmissions during a shared transmit opportunity (TXOP) with a transmit power level that does not interfere with other transmissions. However, in some cases, spatial reuse can have limited efficiency based on certain transmission restrictions.

[0032] According to the techniques described herein, an access point (AP) that acquires a shared TXOP can calculate a transmit power allowed to a neighboring AP (e.g., a neighboring AP having an overlapping basic service set (OBSS)). For example, the AP can limit the transmit power of the neighboring AP based on a certain transmit power calculated by the AP. According to the techniques described herein, the AP can calculate a transmit power limit allowed to the neighboring AP based on one or more determined path losses (e.g., where the path losses can be pre-collected or acquired in any method). The AP can provide information about the maximum transmit power limit and an identifier of the neighboring AP to the neighboring AP (e.g., via an announcement frame).

[0033] Accordingly, the AP and the neighboring AP can effectively share the TXOP, where the AP can transmit a first PPDU to a first station in the OBSS and the neighboring AP can transmit a second PPDU to a second station based on the limited transmit power. In addition, to prevent interference between block acknowledgements (BAs) transmitted from the first station and the second station, the AP can schedule the BAs (e.g., allocate resources for the BAs). Alternatively, in some examples, the transmission of the BA from the second station to the neighboring AP can be delayed by default for the shared TXOP.

[0034] Hereinafter, in certain embodiments, the following description is mainly directed to an orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiplexing access (OFDMA)-based wireless communication system, specifically, to an IEEE 802.11 standard. However, it should be apparent to those skilled in the art that the subject matter described herein can also be slightly changed and applied to other communication systems (e.g., a cellular communication system such as long term evolution (LTE), long term evolution-advanced (LTE-A), new radio (NR), wireless broadband (WiBro), global system for mobile communications (GSM), etc., or a short-range communication system such as Bluetooth, near field communication (NFC), etc.) that can have similar technical backgrounds and channel formats, without departing from the spirit and scope of the present disclosure.

[0035] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation on a suitable computer readable medium between a suitable computer readable medium and a

[0036] Figure 1 is a block diagram illustrating a wireless communication system 10 according to an example embodiment. In some embodiments, the wireless communication system 10 can be a wireless local area network (WLAN) system.

[0037] The wireless communication system 10 can extend a service area through access points. Stations can communicate with another access point at a basic service set (BSS) provided by an access point and connect to a network such as the Internet or an Internet Protocol (IP) network through the access point. For example, as shown in Figure 1 The first access point API can provide a first BSS (BSS1), and the first station STA1, the third station STA3, the fourth station STA4, and the fifth station STA5 can communicate with the first access point API. Additionally or alternatively, the second access point AP2 can provide a second BSS (BSS2), and the first station STA1, the second station STA2, the third station STA3, and the sixth station STA6 can communicate with the second access point AP2.

[0038] As shown in Figure 1 The first station STA1 and the third station STA3 can be connected to both the first access point API and the second access point AP2. In Figure 1 The dashed lines indicate approximate ranges of the first BSS (BSS1) and the second BSS (BSS2), respectively, and can have shapes different from the circular shapes shown in Figure 1

[0039] ​Access points and stations can communicate with each other using wireless fidelity (WiFi) communications or another WLAN communication technology. An access point can be referred to as a router, gateway, etc., and a station can be referred to as a mobile station, subscriber station, terminal, mobile terminal, wireless terminal, user equipment, user, etc. A station can be a mobile device such as a mobile phone, laptop computer, wearable device, etc., or a fixed device such as a desktop computer, smart television, etc. Reference will be made to Figure 17 Examples of access points and stations are described.

[0040] An 802.11 based medium access control (MAC) protocol can consider simultaneous transmission of two or more signals as a collision, and thus, access points and stations can contend to use a channel. For example, access points and stations can communicate with each other based on carrier sense multiple access (CSMA) and / or collision avoidance (CA). Thus, while a first access point AP1 performs a transmission to a first station STA1, a second access point AP2 can delay a transmission to a third station STA3. Collisions can frequently occur in an overlapping basic service set (OBSS) environment in which there are many access points and stations. Thus, performance (e.g., throughput) of the wireless communication system 10 can be limited.

[0041] In some cases, spatial reuse can enable simultaneously generated transmissions that collide with each other. For example, while a first access point AP1 that obtains a transmit opportunity (TXOP) performs a first transmission to a first station STA1, a second access point AP2 can perform a second transmission to a second station STA2 with a transmit power that can not interfere with reception at the first station STA1, instead of delaying the transmission to the second station STA2. Thus, the first transmission to the first station STA1 can be performed in parallel with the second transmission to the second station STA2, and thus, throughput of the wireless communication system 10 can be increased. In this document, a transmission related to an access point that obtains a TXOP can be referred to as a first transmission, and a transmission related to an access point that is provided with a shared TXOP can be referred to as a second transmission.

[0042] In 802.11ax, an access point or station can identify a first transmission based on a preamble and can perform a second transmission that at least partially overlaps with the first transmission with a transmit power determined based on a receive power of the preamble when the first transmission is identified. However, the second transmission can not be considered in the first transmission. Thus, efficiency of spatial reuse can be limited. As will be described below with reference to the drawings, not only the first transmission is considered in the second transmission (e.g., in terms of interference consideration, transmit power consideration, etc.), but also the second transmission is considered in the first transmission in spatial reuse. Thus, more efficient spatial reuse can be achieved.

[0043] In some examples, spatial reuse can rely on or can implement techniques based on an overlapping basic service set partition detection (OBSS-PD) threshold. In some cases, there can be pending transmissions (e.g., frames) in an OBSS. However, in some cases, two access points of an OBSS can share a TXOP (e.g., if there is significant SNR available in the OBSS, if path loss calculations guarantee a shared TXOP, if the transmissions are not very loud, etc.).

[0044] In the following, aspects of the described techniques will be provided with reference to an example in which a first access point AP1 acquires a TXOP and performs a first transmission to a first station STA1, and a second access point AP2 performs a second transmission to a second station STA2 in the shared TXOP, as indicated by the arrows in Figure 1 In this document, spatial reuse of the first transmission by the first access point AP1 taking into account the second transmission by the second access point AP2 can be referred to as coordinated spatial reuse (C-SR). Additionally or alternatively, unless otherwise indicated, the first access point AP1 performing the first transmission can be referred to as a sharing access point or a first apparatus, and the second access point AP2 performing the second transmission can be referred to as a sharing access point or a second apparatus. Furthermore, the first station STA1 receiving the first transmission from the first access point AP1 can be referred to as a third apparatus. The transmission power of the first transmission can be referred to as a first transmission power, and the transmission power of the second transmission can be referred to as a second transmission power.

[0045] Figure 2 is a block diagram illustrating a wireless communication system 20 according to an example embodiment. Figure 2 The block diagram of Figure 2 Each of the first and second wireless communication apparatuses 21 and 22 in can be any apparatus that communicates in the wireless communication system 20, and can be referred to as an apparatus for wireless communication. In some embodiments, each of the first and second wireless communication apparatuses 21 and 22 can be an access point or a station of a WLAN system.

[0046] Reference is made to Figure 2The first wireless communication device 21 can include an antenna 21 2, a transceiver 21 4, and processing circuitry 21 6. In some embodiments, the antenna 21 2, the transceiver 21 4, and the processing circuitry 21 6 can be included in one package, or separately included in different packages. The second wireless communication device 22 can also include an antenna 22 2, a transceiver 22 4, and processing circuitry 22 6. Hereinafter, repeated descriptions of the first wireless communication device 21 and the second wireless communication device 22 will be omitted.

[0047] The antenna 21 2 can receive a signal from the second communication device 22 to provide the signal to the transceiver 21 4, and transmit a signal provided from the transceiver 21 4 to the second wireless communication device 22. In some embodiments, the antenna 21 2 can include multiple antennas for multiple-input multiple-output (MIMO). Also, in some embodiments, the antenna 21 2 can include a phased array for beamforming.

[0048] The transceiver 21 4 can process a signal received through the antenna 21 2 from the second wireless communication device 22, and provide the processed signal to the processing circuitry 21 6. Additionally or alternatively, the transceiver 21 4 can process a signal provided from the processing circuitry 21 6, and output the processed signal through the antenna 21 2. In some embodiments, the transceiver 21 4 can include analog circuitry such as low noise amplifiers, mixers, filters, power amplifiers, oscillators, etc. In some embodiments, the transceiver 21 4 can process a signal received from the antenna 21 2 and / or a signal received from the processing circuitry 21 6 based on a control of the processing circuitry 21 6.

[0049] The transceiver 21 4 can communicate bi-directionally, as described above, with respect to the antenna, wired, or wireless link. For example, the transceiver 21 4 can represent a wireless transceiver and can communicate bi-directionally with another wireless transceiver. The transceiver 21 4 can also include or operate in connection with a modem to modulate the packets and provide the modulated packets to the transceiver for transmission, and to demodulate received packets. In some examples, the transceiver 21 4 can be tuned to operate at specified frequencies. For example, the modem can configure the transceiver 21 4 to operate at a specified frequency and power level based on the communication protocol used by the modem.

[0050] The processing circuitry 21_6 can process signals received from the transceiver 21_4 to extract information transmitted from the second wireless communication device 22. For example, the processing circuitry 21_6 can demodulate and / or decode signals received from the transceiver 21_4 to extract information. Further, the processing circuitry 21_6 can generate signals including information intended for the second wireless communication device 22 to provide to the transceiver 21_4. For example, the processing circuitry 21_6 can encode and / or modulate data intended for the second wireless communication device 22 to generate signals to provide to the transceiver 21_4. In some embodiments, the processing circuitry 216 can include programmable elements such as a central processing unit (CPU) or a digital signal processor (DSP), reconfigurable elements such as a field-programmable gate array (FPGA), or fixed-function elements such as an intellectual property (IP) core. Herein, the transceiver 21_4 and / or the processing circuitry 21_6 performing operations can be referred to as the first wireless communication device 21 performing corresponding operations. Thus, operations to be performed by an access point can be performed by transceivers and / or processing circuitry included in the access point, and operations to be performed by a station can be performed by transceivers and / or processing circuitry included in the station.

[0051] In some examples, the processing circuitry 21_6 can be implemented by a processor. A processor is a hardware device (e.g., a general-purpose processing component, a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, a processor is configured to operate a memory array using a memory controller. In other cases, a memory controller is integrated into a processor. In some cases, a processor is configured to execute computer-readable instructions stored in a memory to perform various functions. In some embodiments, a processor includes special-purpose components for modem processing, baseband processing, digital signal processing, or transmit processing.

[0052] In some cases, software can include code to implement aspects of the present disclosure. The software can be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software can not be directly executable by the processor but can cause a computer (e.g., when compiled and executed) to perform functions described herein.

[0053] Figure 3 is a message diagram illustrating a method for coordinating spatial reuse according to example embodiments. As shown in Figure 3 the method for coordinating spatial reuse can include a number of operations S200, S400, S610, or S620. As referenced above with respect toFigure 1 The first access point AP1 can perform a first transmission to the first station STA1, and the second access point AP2 can perform a second transmission to the second station STA2. Figure 3 The first access point AP1 can perform a first transmission to the first station STA1, and the second access point AP2 can perform a second transmission to the second station STA2.

[0054] Referring to Figure 3 In operation S200, the first access point AP1 can acquire a TXOP. For example, the first access point AP1 can acquire a TXOP for transmitting a physical layer protocol data unit (PPDU) to the first station STA1 with a first transmission power. As described above with reference to Figure 1 The first access point AP1 can acquire the TXOP through contention with at least one station and other access points. For spatial reuse, the TXOP acquired by the first access point AP1 can be shared with the second access point AP2. In some embodiments, unlike the embodiment shown in FIG. 2, when the second access point AP2 acquires a TXOP for transmitting a second PPDU to the second station STA2, the second access point AP2 can perform the first transmission, and the first access point AP1 can also perform the second transmission. Figure 1 The first access point AP1 can perform a first transmission to the first station STA1, and the second access point AP2 can perform a second transmission to the second station STA2.

[0055] In operation S400, the first access point AP1 can limit a second transmission power. The second transmission power can refer to a transmission power used by the second access point AP2 to transmit the second PPDU to the second station STA2. The first access point AP1 can determine the second transmission power and provide information about the determined second transmission power to the second access point AP2. In some embodiments, the first access point AP1 can determine the second transmission power based on at least one path loss. Operation S400 can be included in an announcement phase of coordinated spatial reuse, and examples thereof will be described later with reference to Figure 8 In operation S400, the first access point AP1 can limit a second transmission power. The second transmission power can refer to a transmission power used by the second access point AP2 to transmit the second PPDU to the second station STA2. The first access point AP1 can determine the second transmission power and provide information about the determined second transmission power to the second access point AP2. In some embodiments, the first access point AP1 can determine the second transmission power based on at least one path loss. Operation S400 can be included in an announcement phase of coordinated spatial reuse, and examples thereof will be described later with reference to

[0056] In operation S610, the first access point AP1 can transmit the first PPDU, and the first station STA1 can receive the first PPDU. Additionally or alternatively, in operation S620, the second access point AP2 can transmit the second PPDU, and the second station STA2 can receive the second PPDU. For example, while the first access point AP1 can transmit the first PPDU to the first station with the first transmission power, the second access point AP2 can transmit the second PPDU to the second station STA2 with the second transmission power limited in operation S400. Radio resources used for transmission of the first PPDU and the second PPDU in the shared TXOP can overlap in the time domain and the frequency domain, but due to the second transmission power limited in operation S400, the interference can be removed or reduced. Figure 3The interference is indicated by the dashed line. Thus, the first station STA1 can successfully receive the first PPDU from the first access point AP1 and the second station STA2 can also successfully receive the second PPDU from the second access point AP2.

[0057] In operation S810, the first station STA1 can transmit the first acknowledgement and the first access point AP1 can receive the first acknowledgement. Additionally or alternatively, in operation S820, the second station STA2 can transmit the second acknowledgement and the second access point AP2 can receive the second acknowledgement. Here, the operation S610, the operation S620, the operation S810 and the operation S820 can be included in a transmission phase of coordinated spatial reuse. In some embodiments, the first acknowledgement and the second acknowledgement can be block acknowledgements (BA).

[0058] Figure 4 is a block diagram illustrating a wireless communication system 40 according to an example embodiment. Figure 4 The block diagram of FIG. 1 illustrates an example considering path loss in coordinated spatial reuse. As described above with reference to the accompanying drawings, the first access point AP1 can perform a first transmission to the first station STA1 and the second access point AP2 can perform a second transmission.

[0059] In some embodiments, the first access point AP1 limits the transmission power, i.e. the second transmission power, of the second access point AP2 based on at least one path loss. For example, to determine the second transmission power, the first path loss PL1 between the first access point AP1 and the first station STA1 and the second path loss PL1 between the second access point AP2 and the second station STA2 can be used. As described above, the first path loss PL1 can correspond to a loss in a signal transmitted by the first access point AP1 and the second path loss PL2 can correspond to a loss in a signal transmitted by the second access point AP2. When the first path loss PL1 is lower and the second path loss PL2 is higher, the first station STA1 can more successfully receive the first PPDU from the first access point AP1. Thus, the first access point AP1 can determine the second transmission power based on the first transmission power, the first path loss PL1 and the second path loss PL2. An example for determining the second transmission power by means of the first access point AP1 will be described later with reference to FIG. 4. Figure 4 Figure 8

[0060] ​​In some cases, path loss or path attenuation can refer to a reduction or loss (e.g., attenuation) of a power density of an electromagnetic wave (e.g., a transmitted signal) that propagates through space during transmission from a transmitting device (e.g., an AP) to a receiving device (e.g., a STA). In some cases, path loss can arise due to a wireless communication environment (topography, vegetation and foliage, etc.), a propagation medium (dry or moist air), a distance between a transmitting device and a receiving device, locations of antennas (e.g., height and location), etc. In some cases, path loss can be due to refraction, diffraction, reflection, aperture medium coupling loss, absorption, free space loss, etc. In some examples, a transmit power (e.g., of an AP transceiver, an AP transmitter, etc.) can be determined or calculated based on an identified path loss, as described herein. For example, in scenarios where a path loss between a transmitting device and a receiving device is relatively high, a transmit power can generally be increased, and, in scenarios where a path loss between a transmitting device and a receiving device is relatively low, a transmit power can generally be decreased.

[0061] In some embodiments, the first access point AP1 can identify access points, i.e., neighboring access points (or neighboring devices), around the first access point AP1. For example, the first access point AP1 can identify the second access point AP2 based on a signal received from the second access point AP2 and add the second access point AP2 to the set of candidate access points. Additionally or alternatively, the first access point AP1 can determine a third path loss PL3 between the first access point AP1 and the second access point AP2 based on the signal received from the second access point AP2.

[0062] Figure 5 is a flowchart illustrating a method for coordinating spatial reuse according to an example embodiment, Figure 6 shows a beacon frame 60 according to an example embodiment. Figure 5 The flowchart of Figure 3 Operation S200 of the first access point AP1, and can use the beacon frame 60 in Figure 6 In the following, the operations of Figure 3 will be described with reference to Figure 5 and Figure 6 .

[0063] Reference is made to Figure 5Operation S100 may include operations S110, S120, and S130, and may be included in the preparation phase for coordinating space reuse. In operation S110, the first access point AP1 may receive at least one beacon frame. For example, each access point including the first access point AP1 and the second access point AP2 may periodically or non-periodically output beacon frames, and the first access point AP1 may receive beacon frames from at least one adjacent access point including the second access point AP2.

[0064] refer to Figure 6 The beacon frame 60 may include multiple fields, and each of these fields may include information. For example, such as Figure 6 As shown, beacon frame 60 may include a first field 61 and a second field 62, wherein the first field 61 includes information about coordinated spatial reuse capability, and the second field 62 includes information about the transmission power of beacon frame 60. For example, first access point AP1 may extract the first field 61 from beacon frame 60 received from second access point AP2 and identify whether second access point AP2 supports coordinated spatial reuse based on the value of the first field 61. Additionally or alternatively, first access point AP1 may extract the second field 62 from beacon frame 60 and identify the transmission power used by second access point AP2 to transmit the signal including beacon frame 60 based on the value of the second field 62. In some embodiments, second field 62 may have the same format as the transmission power field included in a transmit power control (TPC) report. Reference will be made to... Figure 11 As described, the second field 62 can be used to determine path loss.

[0065] Refer again Figure 5 In operation S120, the first access point AP1 can identify at least one neighboring device. For example, the first access point AP1 can identify at least one access point based on at least one beacon frame received in operation S110. The first access point AP1 can identify at least one of the at least identified access points capable of spatial reuse as at least one neighboring access point based on the value of the first field 61 included in each of the at least one beacon frame. The first access point AP1 can also be identified as a neighboring access point by a neighboring access point (e.g., AP2) that receives beacon frames from the first access point AP1.

[0066] In operation S130, the first access point AP1 can acquire at least one path loss. The first access point AP1 can collect path loss in various ways. In some embodiments, as will be referred to later... Figure 10As described, the first access point AP1 can receive a report of the first path loss PL1 and the second path loss PL2 from the first station STA1. In some embodiments, the first access point AP1 can estimate the first path loss PL1 and the second path loss PL2 in any manner. Additionally or alternatively, the first access point AP1 can determine the third path loss PL3 based on frames received from the second access point AP2. Reference will be made to Figure 11 An example of operations for determining path losses based on received frames is described. In some embodiments, the operations S130 can be performed prior to, or in parallel with, the operations S110 and S120.

[0067] Figure 7 is a flowchart illustrating a method for coordinating spatial reuse according to an example embodiment. Figure 7 The flowchart of illustrates the operation S300, in which the first access point AP1 selects a second access point (i.e., the second access point AP2) from the at least one neighboring device identified in the operation S120 for spatial reuse to share the TXOP. In some embodiments, the operation S300 can be performed between the operation S200 and the operation S300 in the method of Figure 6 The operation S120 in the method of Figure 1 The operation S200 in the method of Figure 7 may be performed between the operation S300. As shown in Figure 7 , the operation S300 can include the operation S320 and the operation S340, and, in the following, the operation S320 will be described with reference to Figure 4 . Figure 7 .

[0068] With reference to Figure 7 , in the operation S320, the first access point AP1 can identify a device for receiving the first PPDU. As described above with reference to Figure 3 , the first access point AP1 can acquire the TXOP to transmit the first PPDU to the first station STA1. The first access point AP1 can identify the device (i.e., the first station STA1) for receiving the first PPDU to select the device for sharing the TXOP.

[0069] In the operation S340, the first access point AP1 can determine the second access point AP2. For example, the first access point AP1 can determine the second access point AP2 from the neighboring access points based on the first station STA1 identified in the operation S320 and the at least one path loss acquired in the operation S130 in the method of Figure 5 In some embodiments, as shown in Figure 7 , the first access point AP1 can determine the second access point AP2 from the neighboring access points based on the first station STA1 identified in the operation S320 and the at least one path loss acquired in the operation S130 in the method of Figure 3The first access point AP1 can construct a mapping table T70 defining the shared access points corresponding to the stations based on the path losses corresponding to the stations before operation S200 (i.e., before operation S200 of FIG. 2). For example, as one entry, the mapping table T70 can include the station and the access point for which the highest transmission power is used for the second transmission while the first transmission to the station is performed. The first access point AP1 can refer to the mapping table T70 to determine the device identified in operation S320, i.e., the second access point AP2 corresponding to the first station STA1.

[0070] In some embodiments, the first access point AP1 can determine the second access point AP2 from the neighboring access points that forms the highest second path loss PL2 with the first station STA1 to which the first access point AP1 intends to transmit the first PPDU. In some embodiments, the first access point AP1 can also determine the second access point AP2 that forms the highest third path loss PL3 with the first access point AP1. In some embodiments, the first access point AP1 can determine the second access point AP2 based on both the second path loss PL2 and the third path loss PL3. In some embodiments, when the first path loss PL1 is equal to or greater than a predefined threshold, the first access point AP1 can not share the TXOP with another access point to successfully transmit the first PPDU, and thus can not select the second access point AP2.

[0071] In some embodiments, the second access point AP2 can be selected before acquiring the TXOP (i.e., before operation S200 of FIG. 2 is performed). In other words, the first access point AP1 can select the second access point AP2 independently of the device receiving the first PPDU. For example, the first access point AP1 can select the second access point AP2 having the highest path loss with the first access point AP1 based on the path losses collected before acquiring the TXOP. Figure 3

[0072] Figure 8 is a flowchart illustrating a method for coordinating spatial reuse according to an example embodiment. Figure 8 The flowchart of FIG. 4 represents an example of operation S400 of FIG. 4. Figure 3 As described above with reference to Figure 3 , in operation S400' of FIG. 4, the first access point AP1 can limit the second transmission power. As shown in FIG. 4, operation S400' can include operation S420 and operation S440. Hereinafter, operation S420 and operation S440 will be described with reference to Figure 8 Figure 8 As described above with reference to Figure 4 , in operation S420, the first access point AP1 can determine the second transmission power based on the first path loss PL1 and the second path loss PL2. For example, the first access point AP1 can determine the second transmission power based on the first path loss PL1 and the second path loss PL2 according to Equation 1. Figure 8

[0073] Referring to Figure 8 , in operation S420, the first access point AP1 can determine the second transmission power based on the first path loss PL1 and the second path loss PL2. For example, the first access point AP1 can determine the second transmission power based on the first path loss PL1 and the second path loss PL2 according to Equation 1.​​​Figure 4 The signal-to-interference ratio SIR1 of the first station STA1 can be calculated as Equation (1) below.

[0074] SIR1 = (P AP1 - PL1) - (P AP2 - PL2) (1)

[0075] In Equation (1), P AP1 indicates the first transmission power, and P AP2 indicates the second transmission power. On the right side of Equation (1), the first term can correspond to a reception power of a signal received by the first station STA1 from the first access point AP1 (which can be referred to herein as a first reception power), and the second term can correspond to a reception power of a signal received by the first station STA1 from the second access point AP2 (which can be referred to herein as a second reception power). When a minimum signal-to-interference ratio with which the first station STA1 is used to successfully receive the first PPDU is SIR th , SIR1 of Equation (1) can be equal to or greater than SIR th . Thus, a maximum value of the second transmission power P th that satisfies SIR AP2 may also satisfy Equation (2) below (SIR1 = SIR th ).

[0076]

[0077] In other words, the first access point AP1 can determine the second transmission power such that a difference between the first reception power of the first station STA1, which corresponds to a difference between the first transmission power and the first path loss PL1, and the second reception power of the first station STA1, which corresponds to a difference between the second transmission power and the second path loss PL2, is equal to or greater than a reference value (i.e., SIR th ).

[0078] ​In some cases, the transceiver (transceiver 21_4) can include a power amplifier for controlling a transmit power of a transmission. For example, the power amplifier can control or set a power of a transmit signal (such as a PPDU transmission described herein) (e.g., amplify a power of the transmit signal). In some examples, the power amplifier can output the power-amplified transmit signal (e.g., PPDU). In some cases, the power amplifier can amplify a power of the transmit signal to a level that can be radiated through an antenna, to a determined limit of a transmit power of a shared TXOP, and / or the like. In some cases, the power amplifier can be selected from various categories of amplifiers classified according to a shape of an output waveform. For example, the transmit signal (e.g., PPDU) can be a Wi-Fi transmit signal applied to a station (e.g., STAl, STA2, and / or the like). In some examples, a Wi-Fi standard used in the mobile terminal can be at least one from the 802.11 family.

[0079] In operation S440, the first access point AP1 can transmit an announcement frame to the second access point AP2. The announcement frame can include information on the second transmit power determined in operation S420, and the second access point AP2 can identify the second transmit power based on the information on the second transmit power included in the announcement frame received from the first access point AP1. The announcement frame can include additional information used by the second access point AP2 to perform the second transmission, and examples of the announcement frame will be described below with reference to Figure 9A , Figure 9B and Figure 14 .

[0080] Figure 9A and Figure 9B Examples of the announcement frame according to example embodiments are shown. As described above with reference to Figure 8 , the first access point AP1 can transmit an announcement frame 90a of Figure 9A and / or an announcement frame 90b of Figure 9B to the second access point AP2 for coordinating spatial reuse. Hereinafter, repeated descriptions of Figure 9A and Figure 9B will be omitted.

[0081] Referring to Figure 9A , the announcement frame 90a can include a plurality of fields, and each of the plurality of fields can include information. For example, as Figure 9AAs shown, the announcement frame 90a can include a first field 91a and a second field 92a, where the first field 91a includes identification information about the access point, and the second field 92a includes information about the maximum transmit power. For example, the second access point AP2 can extract the first field 91a from the announcement frame 90a received from the first access point AP1, and determine whether the value of the first field 91a matches the identification information of the second access point AP2. Additionally or alternatively, when the value of the first field 91a matches the identification information of the second access point AP2, the second access point AP2 can extract the second field 92a from the announcement frame 90a, and identify the maximum transmit power, i.e., the maximum second transmit power, based on the value of the second field 92a. In some embodiments, the second field 92a can have the same format as the transmit power field included in the TPC report.

[0082] In some embodiments, the announcement frame 90a can include multiple fields for multiple sharing access points. For example, as will be described later with reference to Figure 16 The first access point AP1 can share the TXOP with multiple sharing access points including the second access point AP2, and transmit the announcement frame 90a including information to be provided to the multiple sharing access points. Accordingly, the announcement frame 90a can include multiple first fields for identification information about the multiple sharing access points, and include multiple second fields for maximum transmit powers of the multiple sharing access points. The second access point AP2 can identify a first field matching the identification information of the second access point AP2 from the multiple first fields, select one field from the multiple second fields based on the identified first field (e.g., based on the order of the first fields), and identify the maximum transmit power from the selected second field.

[0083] Referring to Figure 9B , the announcement frame 90b can include multiple fields, and each of the multiple fields can include information. For example, similar to Figure 9A the announcement frame 90a, Figure 9B the announcement frame 90b can include a first field 91b and a second field 92b, and further include a third field 93b. The third field 93b can include information about the range of the TXOP to be shared by the second access point AP2. For example, the third field 93b can include information about available bandwidth, available frequency band, available resource unit, etc., and the second access point AP2 can perform the second transmission based on the value of the third field 93b. Accordingly, the first access point AP1 can share some resources of the TXOP with the second access point AP2 through the third field 93b. Additionally or alternatively, in some embodiments, as described above with reference to Figure 9AAs described, the announcement frame 90b can also include a plurality of third fields corresponding to a plurality of shared access points. Thus, the first access point API can divide and allocate resources to a plurality of shared access points.

[0084] Figure 10 is a message diagram illustrating a method for coordinating spatial reuse according to an example embodiment. Figure 10 The message diagram of Figure 4 illustrates an example of operations of the first access point API for obtaining information about Figure 10 the first path loss PL1 and the second path loss PL2. In some embodiments, Figure 3 the method of Figure 10 may be performed before operation S200 of Figure 10 and is included in a preparation phase of coordinating spatial reuse. In Figure 4 an example of Figure 10 , a beacon frame can be used to determine the path loss, but example embodiments are not limited thereto and can use any frame transmitted by the first access point API and the second access point AP2. As indicated, the method of the first access point API for obtaining information about the path loss can include a plurality of operations S140, S150, S160, S170, and S180. Hereinafter, the operations S140, S150, S160, S170, and S180 will be described with reference to

[0085] . Figure 10 Referring to Figure 6 , in operation S140, the first access point API can transmit a first beacon frame, and the first station STAl can receive the first beacon frame. As described above with reference to Figure 6 , the first beacon frame can include information about a transmission power of the first beacon frame (e.g., 62 of

[0086] In operation S150, the first station STAl can determine the first path loss PL1. As described above with reference to Figure 4 , the first path loss PL1 can correspond to a path loss between the first access point API and the first station STAl, and the first station STAl can determine the first path loss PL1 based on the first beacon frame received in operation S140. An example of operation S150 will be described with reference to Figure 11 .

[0087] In operation S160, the second access point AP2 can transmit a second beacon frame, and the first station STAl can receive the second beacon frame. In operation S170, the first station STAl can determine the second path loss PL2. In some embodiments, unlike the embodiment shown in Figure 10 , operations S160 and S170 can be performed earlier than operations S140 and S150.

[0088] In operation S180, the first station STA1 can report path loss to the first access point AP1. For example, the first station STA1 can provide the first access point AP1 with a message including information about the first path loss PL1 determined in operation S150 and the second path loss PL1 determined in operation S170. Therefore, the first access point AP1 can acquire the first path loss PL1 and the second path loss PL2. In some embodiments, as referenced above... Figure 7 As described, the first access point AP1 can determine the second access point AP2 based on at least one of the first path loss PL1, the second path loss PL2, and the third path loss PL3. Additionally or alternatively, as referenced above... Figure 8 As described, the first access point AP1 can determine the second transmit power based on the first path loss PL1 and the second path loss PL2.

[0089] In some embodiments, with Figure 10 Unlike the embodiments shown, the first station STA1 can report path loss to the first access point AP1. For example, the first station STA1 can report the first path loss to the first access point AP1 after determining the first path loss in operation S150, and report the second path loss to the second access point AP2 after determining the second path loss in operation S170. Additionally or alternatively, in some embodiments, to... Figure 10 The different sequences shown indicate that after determining the second path loss based on the second beacon frame, the first station STA1 can determine the first path loss based on the first beacon frame.

[0090] Figure 11 This is a flowchart illustrating a method for coordinating space reuse according to an example embodiment. Figure 11 Flowchart representation Figure 10 An example of operation S150. See the reference above. Figure 10 As mentioned above, it can be found in Figure 11 The first path loss PL1 is determined in operation S150'. For example... Figure 11 As shown, operation S150' may include multiple operations S152, S154 and S156, and will be referred to below. Figure 4 describe Figure 11 .

[0091] refer to Figure 11 In operation S152, transmission power information can be extracted from the first frame. The first frame may include a field containing information about the transmission power of the first frame (i.e., Figure 6of the first frame. Thus, the first station STA1 can extract the corresponding field from the first frame and identify the transmit power of the first frame based on the value of the extracted field. The first frame can be the beacon frame as described above with reference to Figure 6 or another arbitrary frame (e.g., a trigger frame).

[0092] In operation S154, the transmit power of the first frame can be measured. For example, the first station STA1 can measure the power of a signal including the first frame and received from the first access point API. In some embodiments, the received power of the signal including the first frame can be measured by a power detector included in a transceiver (e.g., 21_4) of the first station STA1. Figure 2

[0093] In operation S156, the first path loss PL1 can be calculated. For example, the first station STA1 can calculate the first path loss PL1 as a difference between the transmit power identified in operation S152 and the received power measured in operation S154. In some embodiments, the first station STA1 in operation S160 of Figure 10 The first station STA1 in operation S160 can determine the second path loss PL2 based on the second frame in a similar manner as described above. Additionally or alternatively, in some embodiments, the first access point API can determine the third path loss PL3 based on the second frame in a similar manner as described above.

[0094] Figure 12 is a timing diagram illustrating transmission based on coordinated spatial reuse according to an example embodiment. Figure 12 The timing diagram of FIG. 21 represents an example of a multi-user (MU) downlink (DL) transmission in which a first access point API (which can be a shared access point) transmits a first PPDU PPDU1 to first stations STA11 and STA12, and a second access point AP2 (which can be a shared access point) transmits a second PPDU PPDU2 to second access stations STA21 and STA22.

[0095] Referring to Figure 12 At time t11, the first access point API can transmit a first beacon frame BF1, and at time t12, the second access point AP2 can transmit a second beacon frame BF2. As described above with reference to Figure 6 ​As described, the first beacon frame BF1 can include identification information about the first access point AP1 and information about a transmission power used to transmit the first beacon frame BF1, and the second beacon frame BF2 can include identification information about the second access point AP2 and information about a transmission power used to transmit the second beacon frame BF2. In some embodiments, the second beacon frame BF2 can be transmitted earlier than the first beacon frame BF1, or the first beacon frame BF1 and the second beacon frame BF2 can be transmitted simultaneously.

[0096] At time t13, the first station STA11 can report the path loss to the first access point AP1. For example, the first station STA11 can determine the path loss between the first access point AP1 and the first station STA11 based on the first beacon frame BF1, and determine the path loss between the second access point AP2 and the first station STA11 based on the second beacon frame BF2. The first station STA11 can transmit a message including the determined path loss to the first access point AP1.

[0097] At time t14, the first station STA12 can report the path loss to the first access point AP1. For example, the first station STA12 can determine the path loss between the first access point AP1 and the first station STA12 based on the first beacon frame BF1, and determine the path loss between the second access point AP2 and the first station STA12 based on the second beacon frame BF2. The first station STA12 can transmit a message including the determined path loss to the first access point AP1.

[0098] At time t15, the first access point AP1 can transmit an announcement frame AF to the second access point AP2. For example, the first access point AP1 can acquire a TXOP for transmitting the first PPDU PPDU1 to the first stations STA11 and STA12. As described above with reference to Figure 9A and Figure 9B As described above with reference to Figure 12 As shown, the period up to time t15, i.e., the period before the first access point AP1 transmits the announcement frame AF (or the period before the TXOP is acquired), can be referred to as a preparation phase. Additionally or alternatively, the period from time t15 to time t16, including the period in which the announcement frame AF is transmitted, can be referred to as an announcement phase.

[0099] In some embodiments, the first access point AP1 can transmit the announcement frame AF to the second access point AP2 in the preparation phase, i.e., before the announcement phase. In some embodiments, the first access point AP1 can transmit the announcement frame AF to the second access point AP2 in the announcement phase, i.e., after the announcement phase starts. Figure 12Unlike the embodiment shown in FIG. 10, the second access point AP2 can transmit an acknowledgement ACK to the first access point AP1 in response to the announcement frame AF in the announcement phase. Thus, the first access point AP1 can identify that the information included in the announcement frame AF is successfully delivered to the second access point AP2 based on the acknowledgement ACK received from the second access point AP2, and enter the transmission phase which will be described later.

[0100] At time t16, the first access point AP1 can transmit the first PPDU PPDU1 to the first stations STA11 and STA12, and the second access point AP2 can transmit the second PPDU PPDU2 to the second stations STA21 and STA22. The first access point AP1 can transmit the first PPDU PPDU1 with the first transmission power in the shared TXOP, and can transmit the second PPDU PPDU2 with the second transmission power in the shared TXOP, the second transmission power being limited to the maximum transmission power identified based on the announcement frame.

[0101] At time t17, the first stations STA11 and STA12 can transmit first acknowledgements BA11 and BA12 to the first access point AP1, respectively, and the second stations STA21 and STA22 can transmit second acknowledgements BA21 and BA22 to the second access point AP2, respectively. As Figure 12 shown, the period from time t16 to time t18 can be referred to as the transmission phase in which the first PPDU PPDU1 and the second PPDU PPDU2 are transmitted in the shared TXOP, and the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 are transmitted.

[0102] As described above, the first access point AP1 can limit the second transmission power of the second access point AP2, i.e., the transmission power to be used for transmitting the second PPDU PPDU2, but the transmission power of the second stations STA21 and STA22, i.e., the transmission power to be used for transmitting the second acknowledgements BA21 and BA22, can not be limited. Thus, as Figure 12 shown, when the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 are transmitted simultaneously between time t17 and time t18, interference can occur. Embodiments for preventing interference between the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 will be described with reference to Figures 13 to 16 FIGS. 11 and 12.

[0103] Figure 13 is a message diagram illustrating a method for coordinating spatial reuse according to an example embodiment. As Figure 13 shown, the method for coordinating spatial reuse can include a plurality of operations S20, S30, S40, S30, S40, S81, or S82. Compared to the method of Figure 3 FIG. 10, the method ofFigure 13 The method may also include operation S30. In the following description... Figure 13 When, the part will be omitted. Figure 3 Repeated description.

[0104] refer to Figure 13 In operation S20, the first access point AP1 can acquire a TXOP. For example, the first access point AP1 can acquire a TXOP for sending a first PPDU to the first station STA1.

[0105] In operation S30, the first access point AP1 can be scheduled and confirmed. (See above for reference.) Figure 12 As described, to prevent interference between a first acknowledgment sent by a first station STA1 to a first access point AP1 and a second acknowledgment sent by a second station STA2 to a second access point AP2, the first access point AP1 can schedule the first and second acknowledgments such that the second acknowledgment is allocated to radio resources that do not overlap with the radio resources allocated to the first acknowledgment. The first access point AP1 can provide the first station STA1 with allocation information regarding the first acknowledgment and provide the second access point AP2 with allocation information regarding the second acknowledgment. The allocation information regarding the second acknowledgment can be provided to the second access point AP2 in various ways. For example, as referenced... Figure 14 As described, the first access point AP1 can provide the second access point AP2 with a declaration frame that includes allocation information about confirmation, or provide a control subfield that includes allocation information about confirmation along with the declaration frame.

[0106] In operation S40, the first access point AP1 can limit the second transmission power. For example, the first access point AP1 can limit the transmission power, i.e., the second transmission power, to be used by the second access point AP2 for transmitting the second PPDU. In operation S61, the first access point AP1 can transmit the first PPDU to the first station STA1, and in operation S62, the second access point AP2 can transmit the second PPDU to the second station STA2. The second access point AP2 can transmit the second PPDU with the second transmission power limited in operation S40. The first PPDU can include allocation information about the first acknowledgement that can be generated in operation S30, and the second PPDU can include allocation information about the second acknowledgement that can be generated in operation S30. In operation S81, the first station STA1 can transmit the first acknowledgement to the first access point AP1, and in operation S82, the second station STA2 can transmit the second acknowledgement to the second access point AP2. The first station STA1 can transmit the first acknowledgement to the first access point AP1 based on the allocation information about the first acknowledgement, which can be included in the first PPDU, and the second station STA2 can transmit the second acknowledgement to the second access point AP2 based on the allocation information about the second acknowledgement, which can be included in the second PPDU. Accordingly, interference between the first acknowledgement and the second acknowledgement can be eliminated.

[0107] Figure 14 An announcement frame 140 according to an example embodiment is illustrated. In some embodiments, Figure 13 The first access point AP1 can transmit Figure 14 the announcement frame 140 to the second access point AP2 to limit the second transmission power and schedule the second acknowledgement. Hereinafter, Figure 13 will be described with reference to Figure 14 .

[0108] With reference to Figure 14 , the announcement frame 140 can include a plurality of fields, and each of the plurality of fields can include information. For example, as illustrated in Figure 9A , similar to the announcement frame 90a of Figure 15A , the announcement frame 140 can include a first field 141 including identification information about an access point and a second field 142 including information about a maximum transmission power, and can further include a third field 143 including allocation information about an acknowledgement.

[0109] The third field 143 can include information about a radio resource to which the second acknowledgement received by the second access point AP2, i.e., the sharing access point, in response to the second PPDU is allocated. In some embodiments, as will be described below with reference to Figure 15BAs described, the third field 143 can include information about the frequency band to which the second acknowledgement is allocated. Additionally or alternatively, in some embodiments, as will be described below with reference to Figure 9B As described, the third field 143 can also include information about the time band to which the second acknowledgement is allocated. The second access point AP2 can identify the radio resources to which the second acknowledgement is allocated based on the value of the third field 143 and provide the second station STA2 with allocation information about the second acknowledgement, such as information about the radio resources to which the second acknowledgement is allocated.

[0110] In some embodiments, the allocation information about the acknowledgement can be included in the HT Control field of 802.11. For example, the first access point AP1 can generate an HT Control field including information about the radio resources to which the second acknowledgement is allocated and transmit the HT Control field to the second access point AP2 together with the announcement frame (e.g., the HT Control field is appended to the announcement frame).

[0111] In some embodiments, the third field 143 can include a value indicating whether the acknowledgement of the allocation of the radio resources is activated. For example, when the third field 143 has a predefined first value, the sharing access point can identify that there is no radio resource to which the acknowledgement is allocated individually and can transmit the acknowledgement in the shared TXOP. In some embodiments, as described above with reference to Figure 9B As described, when the announcement frame 140 includes a field indicating information about the range of the shared TXOP (e.g., the field 93b of Figure 15A the sharing access point can transmit the acknowledgement within the range of the TXOP in response to the first value of the third field 143.

[0112] Figure 15B and Figure 15A is a timing diagram illustrating an example of transmission based on coordinated spatial reuse according to an example embodiment. Figure 15B and Figure 12 The timing diagram of Figure 12 indicates an example of a transmission phase of coordinated spatial reuse in a wireless communication system including a first access point AP1, first stations STA11 and STA12, a second access point AP2, and second stations STA21 and STA22 as an example of Figure 15A will be described below with reference to Figure 15B and Figure 15A and repetitive description about Figure 15B and Figure 15A will be omitted.

[0113] Referring to Figure 15A , the first PPDU PPDU1 and the second PPDU PPDU2 can be transmitted between the time t21 and the time t22. As Figure 15AAs shown, the first PPDU PPDU1 and the second PPDU PPDU2 can be transmitted within a shared bandwidth BW. For example, each of the first PPDU PPDU1 and the second PPDU PPDU2 can be allocated to an arbitrary resource unit within the bandwidth BW. In some embodiments, the bandwidth can correspond to one of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0114] The first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 can be transmitted at time t23 and time t24. As shown, the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 can be transmitted at time t23 and time t24, respectively, after a short interframe space (SIFS) from time t22. Figure 15A As shown, the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22 can be transmitted at time t23 and time t24, respectively, after a short interframe space (SIFS) from time t22. To prevent interference between the first acknowledgements BA11 and BA12 and the second acknowledgements BA21 and BA22, the first access point AP1 can allocate the first acknowledgements BA11 and BA12 to the upper band UB of the bandwidth BW and allocate the second acknowledgements BA21 and BA22 to the lower band LB of the bandwidth BW. Thus, the first stations STA11 and STA12 can transmit the first acknowledgements BA11 and BA12 to the first access point AP1 through resource units included in the upper band UB of the bandwidth BW, and the second stations STA21 and STA22 can transmit the second acknowledgements BA21 and BA22 to the second access point AP2 through resource units included in the lower band LB of the bandwidth BW.

[0115] In some embodiments, in a multi-user (MU) environment, an access point can allocate acknowledgements to different radio resources. For example, as shown, the first access point AP1 can allocate the first acknowledgements BA11 and BA12 to respective different frequency bands within the upper band UB. Additionally or alternatively, the first access point AP2 can allocate the second acknowledgements BA21 and BA22 to respective different frequency bands within the lower band LB. Figure 15B

[0116] Referring to FIG. 3A, Figure 15B The first PPDU PPDU1 and the second PPDU PPDU2 can be transmitted between time t31 and time t32. As shown, the first PPDU PPDU1 and the second PPDU PPDU2 can be transmitted within a shared bandwidth BW. Figure 14 As shown, the first PPDU PPDU1 and the second PPDU PPDU2 can be transmitted within a shared bandwidth BW.

[0117] ​The first acknowledgements BA11 and BA12 can be transmitted between time t33 and time t34. In some embodiments, the first stations STAl 1 and STA12 can transmit the first acknowledgements BA11 and BA12 to the first access point API between time t33 and time t34 based on allocation information about the first acknowledgements BA11 and BA12 provided from the first access point API. In some embodiments, the first access point API can not provide allocation information about the first acknowledgements BA11 and BA12 to the first stations STAl 1 and STA12, and the first stations STAl 1 and STA12 can transmit the first acknowledgements BA11 and BA12 to the first access point API between time t33 and time t34 based on a default setting after SIFS from t32.

[0118] The second acknowledgements BA21 and BA22 can be transmitted between time t35 and time t36. In some embodiments, the second access point AP2 can identify the delayed transmission of the second acknowledgements BA21 and BA22 based on allocation information about the second acknowledgements BA21 and BA22 included in the announcement frame, and provide the delayed second acknowledgements BA21 and BA22 to the second stations STA21 and STA22. In some embodiments, the second access point AP2 can provide information for delaying the second acknowledgements BA21 and BA22 to the second stations STA21 and STA22 when the shared access point is identified based on the identification information included in the announcement frame. Thus, the allocation information about the second acknowledgements BA21 and BA22 (e.g., 143) can be omitted. Figure 16

[0119] Figure 16 is a block diagram illustrating a wireless communication system 160 according to an example embodiment. As shown in Figure 17 the wireless communication system 160 can include first to fifth access points API 1 to AP15.

[0120] In some embodiments, the shared access point can share the TXOP with a plurality of shared access points. For example, when acquiring the TXOP for transmitting the PPDU, the first access point API 1 can share the TXOP with the second to fifth access points AP12 to AP15 among the neighboring access points. Thus, the first access point API 1 can determine transmission power of the second to fifth access points AP12 to AP15 based on at least one path loss, and transmit an announcement frame including information about the determined transmission power to the second to fifth access points AP12 to AP15. Each of the second to fifth access points AP12 to AP15 can transmit the PPDU with transmission power limited based on the information about the transmission power included in the announcement frame, and thus, the efficiency of the wireless communication system 160 can be significantly improved.

[0121] ​In some embodiments, the sharing access point can allocate radio resources to be used for transmission of a plurality of sharing access points. For example, when acquiring a TXOP for transmitting a PPDU, the first access point AP 11 can allocate a higher band of bandwidth to the second access point AP 12 and the fifth access point AP 15, and allocate a lower band of bandwidth to the third access point AP 13 and the fourth access point AP 14. Accordingly, the first access point AP 11 can transmit resource allocation information, i.e., an announcement frame including allocation information about the frequency band, and each of the second access point AP 12 to the fifth access point AP 15 can identify the frequency band based on the allocation information about the frequency band included in the announcement frame, and transmit a PPDU to at least one station in the identified frequency band.

[0122] Figure 17 An example of an apparatus for wireless communication according to an example embodiment is shown. Figure 13 An Internet of Things (IoT) network system is represented, which includes a home gadget 171, a home appliance 172, an entertainment device 173, and an access point 175.

[0123] In some embodiments, in the apparatus for wireless communication ​ In the apparatus for wireless communication, the method for coordinating spatial reuse described above with reference to the accompanying drawings can be performed. For example, the access point 175 (i.e., a sharing access point) acquiring a TXOP can share the TXOP with neighboring access points (i.e., sharing access points), and transmit a PPDU to the home gadget 171, the home appliance 172, and the entertainment device 173 in the shared TXOP. In some embodiments, the home gadget 171, the home appliance 172, and / or the entertainment device 173 can report at least one path loss to the access point 175, and the access point 175 can limit transmission power of the neighboring access points in the shared TXOP based on the at least one path loss. Accordingly, the home gadget 171, the home appliance 172, and / or the entertainment device 173 can successfully receive the PPDU, and the neighboring access points can not delay transmission of the PPDU. Therefore, efficiency of the IoT network system can be improved.

[0124] While the inventive concept has been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details can be made therein without departing from the spirit and scope of the appended claims.

Claims

1. A method of wireless communication performed by a first apparatus, the method comprising: acquiring a transmit opportunity (TXOP) for transmitting a first physical layer protocol data unit (PPDU) with a first transmit power; determining a limit on a second transmit power to a second apparatus and sharing the TXOP with the second apparatus based at least in part on the determined limit on the second transmit power; transmitting the first PPDU with the first transmit power to a third apparatus in the shared TXOP; and outputting a beacon frame including capability information and transmit power information, wherein the capability information indicates support for spatial reuse, and the transmit power information indicates a transmit power of the beacon frame, wherein determining the limit on the second transmit power comprises determining the second transmit power based on a first path loss and a second path loss, the first path loss comprising a path loss between the first apparatus and the third apparatus, and the second path loss comprising a path loss between the second apparatus and the third apparatus, wherein the first path loss is based on the transmit power indicated by the transmit power information and a received power of the beacon frame measured by the third apparatus.

2. The method of wireless communication of claim 1, further comprising: receiving at least one frame; identifying at least one neighboring apparatus configured to support spatial reuse based on the at least one frame; and determining at least one path loss.

3. The method of wireless communication of claim 2, further comprising: selecting the second apparatus from the at least one neighboring apparatus, wherein selecting the second apparatus comprises: identifying the third apparatus; and selecting the second apparatus based on the identified third apparatus and the at least one path loss. determining the second transmit power comprises calculating the second transmit power based on a difference between a first received power of the third apparatus and a second received power of the third apparatus being equal to or greater than a reference value, wherein the first received power corresponds to a difference between the first transmit power and the first path loss, and wherein the second received power corresponds to a difference between the second transmit power and the second path loss.

4. The wireless communication method of claim 1, wherein, determining the limit on the second transmit power further comprises transmitting apparatus identification information to the second apparatus, wherein the apparatus identification information includes an identifier of the second apparatus and information regarding the second transmit power.

5. The wireless communication method of claim 1, wherein, 6. The method of wireless communication of claim 1, further comprising: receiving information regarding the first path loss, information regarding the second path loss, or both information regarding the first path loss and information regarding the second path loss from the third apparatus.

7. The method of wireless communication of claim 1, further comprising: allocating at least one first acknowledgement corresponding to the first PPDU and at least one second acknowledgement corresponding to a second PPDU to respective different radio resources, wherein the second PPDU is transmitted by the second apparatus in the shared TXOP; and transmitting resource allocation information regarding the at least one first acknowledgement and the at least one second acknowledgement to the second apparatus. allocating the at least one first acknowledgement and the at least one second acknowledgement to respective different radio resources comprises:

8. The wireless communication method of claim 7, wherein, allocating the at least one first acknowledgement to a first frequency band; and allocating the at least one second acknowledgement to a second frequency band. allocating the at least one second acknowledgement to a second frequency band different from the first frequency band. 9.The wireless communication method of claim 1, further comprising: determining a limit on a third transmit power of the fourth apparatus for sharing the TXOP with the fourth apparatus. 10.The wireless communication method of claim 9, further comprising: allocating the transmission of the second apparatus and the transmission of the fourth apparatus to respective different radio resources; and transmitting, to the second apparatus and the fourth apparatus, resource allocation information on the transmission of the second apparatus and the transmission of the fourth apparatus. 11.A wireless communication method performed by a second apparatus sharing a transmission opportunity (TXOP) with a first apparatus, the method comprising: outputting a beacon frame including capability information and first transmit power information, wherein the capability information indicates support for spatial reuse, and the first transmit power information indicates a first transmit power of the beacon frame; receiving, from the first apparatus, second transmit power information; and transmitting, to at least one third apparatus, a physical layer protocol data unit (PPDU) in the TXOP with a second transmit power equal to or lower than a transmit power indicated by the second transmit power information, wherein the second transmit power information is based on a first path loss including a path loss between the first apparatus and the third apparatus, and a second path loss including a path loss between the second apparatus and the third apparatus, wherein the second path loss is based on a first transmit power indicated by the first transmit power information and a received power of the beacon frame measured by the third apparatus. 12.The wireless communication method of claim 11, further comprising: receiving, from the first apparatus, apparatus identification information; and identifying sharing of the TXOP based on the apparatus identification information. 13.The wireless communication method of claim 11, further comprising: receiving, from the first apparatus, resource allocation information on at least one acknowledgement corresponding to the PPDU; and transmitting, to the at least one third apparatus, the resource allocation information. 14.The wireless communication method of claim 11, further comprising: receiving, from the at least one third apparatus, at least one second acknowledgement after receiving at least one first acknowledgement corresponding to a PPDU transmitted by the first apparatus in the TXOP. A third apparatus receiving a physical layer protocol data unit (PPDU) in a transmission opportunity (TXOP) shared by a first apparatus and a second apparatus, the method comprising: determining a first path loss between the first apparatus and the third apparatus based on a first beacon frame received from the first apparatus, wherein the first beacon frame includes capability information and transmit power information, wherein the capability information indicates support for spatial reuse, and the transmit power information indicates a transmit power of the first beacon frame; determining a second path loss between the second apparatus and the third apparatus based on a second beacon frame received from the second apparatus; 15. A method of wireless communication performed by a third apparatus, comprising: transmitting, to the first apparatus, information on the first path loss and the second path loss; and receiving, from the first apparatus, the PPDU in the TXOP, ​ ​ ​ wherein the first path loss is determined based on a transmit power indicated by the transmit power information and a measured receive power of the first beacon frame.

16. The wireless communication method according to claim 15, further comprising: receiving, from the first apparatus, resource allocation information on an acknowledgement corresponding to the PPDU; and transmitting, to the first apparatus, the acknowledgement based on the resource allocation information.

17. The wireless communication method of claim 16, wherein, The resource allocation information indicates a frequency band for transmitting the acknowledgement.

Images