WO2025230229A1 - Individual signaling method and apparatus for periodic in-device coexistence service period in wireless lan system - Google Patents

Abstract

Disclosed are an individual signaling method and apparatus for a periodic in-device coexistence (IDC) period in a wireless LAN system. The method according to an embodiment of the present disclosure may comprise the steps of: transmitting, by a first station (STA), a first frame including a first element to a second STA; and performing, by the first STA, an IDC operation in an IDC service period (SP) based on information included in the first element. On the basis that the first element includes a control field, a specific bit of the control field may indicate whether the first element includes information related to IDC.

Description

Method and device for individual signaling for periodic device-to-device coexistence service periods in wireless LAN systems

The present disclosure relates to an individual signaling method and device for periodic in-device coexistence (IDC) service periods in a wireless local area network (WLAN) system.

New technologies have been introduced for wireless local area networks (WLANs) to improve transmission rates, increase bandwidth, enhance reliability, reduce errors, and reduce latency. Among WLAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, recently introduced technologies for WLANs include enhancements for Very High Throughput (VHT) in the 802.11ac standard and enhancements for High Efficiency (HE) in the IEEE 802.11ax standard.

To provide a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO), which supports increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, and for coordination of multiple access points (APs), are being studied. In particular, various technologies are being studied to support low latency or real-time traffic. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technology.

The technical problem of the present disclosure is to provide a method and device for individually signaling the periodic IDC service period of a device to another device in a wireless LAN system.

The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

A method according to one aspect of the present disclosure may include the steps of transmitting, by a first station (STA), a first frame including a first element to a second STA; and performing, by the first STA, an intra-device coexistence (IDC) operation during an IDC service period (SP) based on information included in the first element. Based on the first element including a control field, a specific bit of the control field may indicate whether the first element includes information related to intra-device coexistence (IDC).

A method according to an additional aspect of the present disclosure may include receiving, by a second station (STA), a first frame including a first element from a first STA; and performing an operation of the second STA related to an intra-device coexistence (IDC) operation by the first STA during an IDC service period (SP) based on information included in the first element. Based on the first element including a control field, a specific bit of the control field may indicate whether the first element includes information related to intra-device coexistence (IDC).

According to the present disclosure, a method and apparatus for individually signaling the periodic IDC service period of a device to another device may be provided.

The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

FIG. 5 is a diagram for explaining a CSMA/CA-based frame transmission operation to which the present disclosure can be applied.

FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

FIG. 8 is a drawing illustrating an example of an individual TWT operation to which the present disclosure can be applied.

FIG. 9 is a diagram illustrating an example of a broadcast TWT operation to which the present disclosure can be applied.

Figure 10 is a drawing for explaining an example of a TWT information element format.

Figure 11 is a diagram illustrating examples of individual TWT parameter set field formats.

Figure 12 is a diagram illustrating examples of broadcast TWT parameter set field formats.

FIG. 13 is a diagram illustrating an example of a collision caused by an IDC to which the present disclosure can be applied.

FIG. 14 is a diagram showing an example of the operation of the first STA according to the present disclosure.

FIG. 15 is a diagram showing an example of the operation of a second STA according to the present disclosure.

FIG. 16 and FIG. 17 are diagrams showing examples of an IDC event signaling procedure according to the present disclosure.

FIG. 18 is a diagram illustrating exemplary formats of channel usage elements according to the present disclosure.

FIG. 19 is a diagram showing an exemplary format of a channel use request frame according to the present disclosure.

FIG. 20 is a diagram showing an exemplary format of an IDC TWT element according to the present disclosure.

FIG. 21 illustrates examples of an IDC TWT parameter set format including IDC information according to the present disclosure.

FIG. 22 illustrates examples of the format of a request type field within an IDC TWT parameter set field containing IDC information according to the present disclosure.

Figure 23 illustrates an exemplary format of an IDC information field according to the present disclosure.

Figure 24 illustrates additional examples of IDC information fields according to the present disclosure.

FIG. 25 illustrates an example of a periodic IDC SP according to an IDC request and IDC response exchange according to the present disclosure.

FIG. 26 illustrates an example of a periodic IDC SP according to an unsolicited IDC setup according to the present disclosure.

Figure 27 illustrates another example of a periodic IDC SP according to an unsolicited IDC setup according to the present disclosure.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and/or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and/or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of "/" between words in this disclosure has the same meaning as "and/or" unless otherwise stated.

The examples of the present disclosure can be applied to various wireless communication systems. For example, the examples of the present disclosure can be applied to a wireless LAN system. For example, the examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a/g/n/ac/ax/be standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Additionally, the examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a cellular wireless communication system. For example, the examples of the present disclosure can be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series of technologies and the 5G NR (New Radio) series of technologies of the 3rd Generation Partnership Project (3GPP) standard.

Below, technical features to which examples of the present disclosure can be applied are described.

FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

The first device (100) and the second device (200) illustrated in FIG. 1 may be replaced with various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. In addition, the first device (100) and the second device (200) may be replaced with various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (Base Transceiver System), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

The devices (100, 200) illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices (100, 200) illustrated in FIG. 1 may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, the STAs (110, 200) may perform an AP (access point) role or a non-AP role. That is, in the present disclosure, the STAs (110, 200) may perform the functions of an AP and/or a non-AP. When the STAs (110, 200) perform an AP function, they may simply be referred to as APs, and when the STAs (110, 200) perform a non-AP function, they may simply be referred to as STAs. In addition, in the present disclosure, the APs may also be referred to as AP STAs.

Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) can include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that follow the provisions of the IEEE 802.11 standard.

In addition, the first device (100) and the second device (200) may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than wireless LAN technology. In addition, the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and/or one or more antennas (108). The processor (102) controls the memories (104) and/or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memories (104) to generate first information/signals, and then transmit a wireless signal including the first information/signals via the transceivers (106). Furthermore, the processor (102) may receive a wireless signal including second information/signals via the transceivers (106), and then store information obtained from signal processing of the second information/signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in the present disclosure. Here, the processor (102) and the memory (104) may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (106) may be connected to the processor (102) and may transmit and/or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and/or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present disclosure, a device may also mean a communication modem/circuit/chip.

The second device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and/or one or more antennas (208). The processor (202) controls the memories (204) and/or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memory (204) to generate third information/signals, and then transmit a wireless signal including the third information/signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information/signals via the transceivers (206), and then store information obtained from signal processing of the fourth information/signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in the present disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (206) may be connected to the processor (202) and may transmit and/or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and/or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present disclosure, a device may also mean a communication modem/circuit/chip.

Hereinafter, the hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in the present disclosure, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and/or operational flowcharts disclosed in the present disclosure.

One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods and/or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods and/or operation flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and/or sets of instructions.

One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and/or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and/or combinations thereof. The one or more memories (104, 204) may be located internally and/or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

One or more transceivers (106, 206) can transmit user data, control information, wireless signals/channels, etc., as mentioned in the methods and/or flowcharts of the present disclosure, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals/channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and/or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals/channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) may convert received user data, control information, wireless signals/channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals/channels, etc. using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals/channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and/or a filter.

For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceivers (106, 206) of FIG. 1 may perform transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) according to IEEE 802.11a/b/g/n/ac/ax/be/bn, etc.). In addition, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) of FIG. 1. For example, an example of an operation for generating a transmission/reception signal or performing data processing or operation in advance for a transmission/reception signal may include 1) an operation for determining/obtaining/configuring/computing/decoding/encoding bit information of a field (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in a PPDU, 2) an operation for determining/configuring/obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 3) an operation for determining/configuring/obtaining a specific sequence (e.g., a pilot sequence, an STF/LTF sequence, an extra sequence applied to SIG) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 4) a power control operation and/or a power saving operation applied to an STA, 5) an operation related to determining/obtaining/configuring/computing/decoding/encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields/subfields/control fields/parameters/power, etc.) used by various STAs for determining/acquiring/configuring/computing/decoding/encoding transmission/reception signals can be stored in the memory (104, 204) of FIG. 1.

Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs/packets/signals, etc. can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs/packets/signals, etc. can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports transparent STA mobility to the upper layer can be provided. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates, by way of example, the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The oval representing a BSS in FIG. 2 can also be understood as representing a coverage area in which STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). When an STA moves outside of a BSA, it cannot directly communicate with other STAs within the BSA.

If we do not consider the DS illustrated in Figure 2, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of WLAN, a LAN can be configured when needed rather than being planned in advance, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to distributed systems (DS) is not permitted, forming a self-contained network.

An STA's membership in a BSS can dynamically change, for example, when an STA is turned on or off, or when an STA enters or leaves a BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services in the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may involve the use of a Distribution System Service (DSS).

In a wireless LAN, the direct STA-to-STA distance can be limited by PHY performance. While this distance limit may be sufficient in some cases, communication between STAs over longer distances may be required in other cases. To support extended coverage, a distributed system (DS) can be configured.

DS refers to a structure in which BSSs are interconnected. Specifically, a BSS may exist as an extended component of a network composed of multiple BSSs, as illustrated in Figure 2. DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the Wireless Medium (WM) and DSM can be logically distinguished. Each logical medium is used for a different purpose and by different components. These media are neither limited to being identical nor limited to being different. This logical difference between multiple media explains the flexibility of the WLAN architecture (DS architecture or other network architectures). In other words, the WLAN architecture can be implemented in various ways, and the physical characteristics of each implementation can independently specify the WLAN architecture.

A DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary to handle addresses to destinations. Additionally, a DS may further include a component called a portal, which acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).

An AP is an entity that enables access to a DS through a WM for associated non-AP STAs and also has the functionality of an STA. Data movement between a BSS and a DS can be performed through an AP. For example, STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since all APs are basically STAs, all APs are addressable entities. The address used by an AP for communication on a WM and the address used by an AP for communication on a DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be referred to as an infrastructure BSS.

Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP may always be received on an uncontrolled port and processed by an IEEE 802.1X port access entity. In addition, if the controlled port is authenticated, the transmitted data (or frame) may be forwarded to the DS.

In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

An ESS is a network of arbitrary size and complexity, consisting of DSs and BSSs. An ESS may correspond to a set of BSSs connected to a DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is the identifier of the BSS.

In a wireless LAN system, no assumptions are made about the relative physical locations of BSSs, and all of the following configurations are possible: BSSs can be partially overlapping, which is commonly used to provide continuous coverage. BSSs can also be physically disconnected, and there is no logical distance limit between them. BSSs can also be physically co-located, which can be used to provide redundancy. Furthermore, one (or more) IBSS or ESS networks can physically co-exist with one (or more) ESS networks. This can occur in cases where an ad-hoc network operates at the same location as an ESS network, where physically overlapping wireless networks are configured by different organizations, or where two or more different access and security policies are required at the same location.

FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning operations by the STA. That is, for the STA to access a network, it must search for available networks. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning.

Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation including an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover any APs in the vicinity while moving between channels and waits for a response. The responder transmits a probe response frame in response to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits the beacon frame, so the AP becomes the responder. In the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests/responses on channel 2) in the same manner.

Although not shown in Figure 3, the scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves between channels and waits for a beacon frame. A beacon frame is one of the management frames defined in IEEE 802.11. It announces the existence of a wireless network and is periodically transmitted so that the STA performing the scanning can find the wireless network and participate in the wireless network. In the BSS, the AP performs the role of periodically transmitting the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. The STA receiving the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel to perform scanning on the next channel in the same manner. Comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below.

The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request/response corresponds to a management frame.

The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request/response frame, and may be replaced with other information or include additional information.

An STA can send an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

For example, the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information about various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. These are just some examples of information that may be included in a combined request/response frame, and may be replaced by other information or include additional information.

After the STA successfully joins the network, a security setup process may be performed in step S340. The security setup process in step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request/response, the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may also be referred to simply as an authentication process.

The security setup process of step S340 may include, for example, a process of establishing a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame. Furthermore, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). The CSMA/CA mechanism, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and/or STA may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and/or STA may start transmitting frames through the medium. On the other hand, if the medium is detected to be occupied or busy, the AP and/or STA may not start its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access before attempting to transmit frames. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

In addition, the IEEE 802.11 MAC protocol provides the Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls all receiving APs and/or STAs to ensure that they receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method for a provider to provide data frames to multiple users, while the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism to improve the Quality of Service (QoS) of the wireless LAN, and can transmit QoS data in both the Contention Period (CP) and the Contention Free Period (CFP).

Referring to Fig. 4, an operation based on a random backoff period is described. When an occupied/busy medium changes to an idle state, multiple STAs may attempt to transmit data (or frames). To minimize collisions, each STA may select a random backoff count, wait for the corresponding slot time, and then attempt transmission. The random backoff count has a pseudo-random integer value and may be determined as one of the values in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is initially given a value of CWmin, but may double the value in case of a transmission failure (e.g., if an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. It is desirable that the CW, CWmin and CWmax values be set to 2 ⁿ -1 (n=0, 1, 2, ...).

Once the random backoff process begins, the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits. When the medium becomes idle, the remaining countdown resumes.

In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit a frame if it confirms that the medium is idle for DIFS. The remaining STAs monitor the medium for occupied/busy states and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can count down the backoff slot according to a random backoff count value selected by each STA after waiting for DIFS if the medium is monitored as idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. In other words, this example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 briefly stop counting down and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that they had stopped. That is, they can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, counts down according to its selected random backoff count value, and then starts transmitting frames. In the example of Figure 4, the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which case a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failure in data transmission. In this case, STA4 and STA5 can select a random backoff count value and perform a countdown after doubling the CW value. STA1 waits while the medium is occupied by transmissions from STA4 and STA5, and when the medium becomes idle, it waits for DIFS and can start transmitting frames after the remaining backoff time elapses.

As in the example of Fig. 4, a data frame is a frame used for transmitting data forwarded to a higher layer, and can be transmitted after a backoff performed after DIFS elapses from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS elapses, such as DIFS or PIFS (Point coordination function IFS). Subtype frames of a management frame include a beacon, an association request/response, a re-association request/response, a probe request/response, and an authentication request/response. A control frame is a frame used to control access to the medium. The subtype frames of the control frame include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP), and Trigger. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff performed after the DIFS (Direct Inverse Frame Stop) has elapsed, and if it is a response frame to the previous frame, it is transmitted without a backoff performed after the SIFS (short IFS). The type and subtype of the frame can be identified by the type field and subtype field in the Frame Control (FC) field.

A QoS (Quality of Service) STA can transmit a frame after a backoff performed after the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.

FIG. 5 is a diagram for explaining a CSMA/CA-based frame transmission operation to which the present disclosure can be applied.

As mentioned above, the CSMA/CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of an STA can utilize a Network Allocation Vector (NAV). The NAV is a value that an STA that is currently using or has the right to use the medium indicates to other STAs the remaining time until the medium becomes available. Therefore, the value set as NAV corresponds to the period during which the STA transmitting the frame is scheduled to use the medium, and an STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the MAC header of the frame.

In the example of FIG. 5, it is assumed that STA1 wants to transmit data to STA2, and STA3 is in a position to overhear some or all of the frames transmitted and received between STA1 and STA2.

In order to reduce the possibility of collisions in transmissions of multiple STAs in a CSMA/CA-based frame transmission operation, a mechanism using RTS/CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA1 may correspond to a hidden node for STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA2 may correspond to a hidden node for STA3. By exchanging RTS/CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

Specifically, STA1 can determine whether a channel is occupied through carrier sensing. In terms of physical carrier sensing, STA1 can determine channel occupancy idleness based on the energy level or signal correlation detected in the channel. Furthermore, in terms of virtual carrier sensing, STA1 can determine the channel occupancy status using a network allocation vector (NAV) timer.

STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during the DIFS. STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after an SIFS if it receives the RTS frame.

If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information contained in the RTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can use the duration information contained in the CTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

If STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the CTS frame is completely received. If STA2 successfully receives the data frame, it can transmit an ACK frame in response to the data frame to STA1 after SIFS. STA3 can determine whether the channel is in use through carrier sensing if the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during the DIFS after the NAV timer expires, it can attempt channel access after a contention window (CW) based on a random backoff has elapsed.

FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the start of transmission of the PHY layer is received from the MAC layer, the PHY layer can switch to transmission mode and transmit the information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble of the received frame, it monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception of the PHY layer.

In this way, information transmission/reception in a wireless LAN system is done in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL (SIG) field, and a Data field. The most basic (e.g., non-HT (High Throughput) as illustrated in FIG. 7) PPDU format may consist of only the Legacy-STF (L-STF), Legacy-LTF (L-LTF), Legacy-SIG (L-SIG) fields, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field may consist of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of data. For example, the 12-bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

The data field may include a SERVICE field, a Physical layer Service Data Unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used to synchronize the descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated/used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of MAC PDUs and can be transmitted/received through the PSDU in the data portion of the PPDU format.

The MAC header includes a Frame Control field, a Duration/ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission/reception. The Duration/ID field may be set to a time for transmitting the corresponding frame, etc. The Address subfields may indicate the receiver address, transmitter address, destination address, and source address of the frame, and some Address subfields may be omitted. For specific details of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, refer to the IEEE 802.11 standard document.

The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if additionally present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in the general PPDU format, and does not include the remaining part (i.e., data field).

FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

Standards such as IEEE 802.11a/g/n/ac/ax use various PPDU formats. The basic PPDU format (IEEE 802.11a/g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (Fig. 7(a)).

The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in Fig. 7(b) may be referred to as an HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).

An example of the VHT PPDU format (IEEE 802.11ac) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

An example of a HE PPDU format (IEEE 802.11ax) additionally includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-users (MUs), but the HE PPDU format for single users (SUs) does not include the HE-SIG-B. In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16us. For example, RL-SIG can be configured identically to L-SIG. The receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of RL-SIG.

The EHT PPDU format may include the EHT MU (multi-user) PPDU of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following an L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

The EHT MU PPDU in FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

The EHT TB PPDU of Fig. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. An STA that has received a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated to allow legacy STAs to attempt demodulation and decoding, and mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated to allow STAs that have successfully decoded non-legacy SIGs (e.g., U-SIG and/or EHT-SIG) and obtained the information contained in the fields, and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.

The U-SIG included in the EHT PPDU format of FIG. 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 us, and the U-SIG can have a total duration of 8 us. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

U-SIGs can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be duplicated in 20MHz units. That is, four identical U-SIGs can be included in an 80MHz PPDU. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the U-SIGs in the first 80MHz unit and the U-SIGs in the second 80MHz unit can be different.

For example, A uncoded bits may be transmitted via U-SIG, and a first symbol of U-SIG (e.g., a U-SIG-1 symbol) may transmit the first X bits of information out of a total A bits of information, and a second symbol of U-SIG (e.g., a U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits in length) and a tail field (e.g., a field of 6 bits in length). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

The A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in a new PPDU format (e.g., UHR PPDU format) not shown in FIG. 7, and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits can be the same, and some or all of the version-dependent bits can be different.

For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits can be assigned only to U-SIG-1 symbols, or to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDUs. The version-independent bits of the U-SIG may include a 1-bit UL/DL flag field. The first value of the 1-bit UL/DL flag field relates to UL communication, and the second value of the UL/DL flag field relates to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmission opportunity (TXOP) and information about a BSS color ID.

For example, the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

Some of the information required for transmitting and receiving a PPDU may be included in the U-SIG and/or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of the non-legacy LTF/STF (e.g., EHT-LTF/EHT-STF or UHR-LTF/UHR-STF, etc.), information about the length of the non-legacy LTF and the cyclic prefix (CP) length, information about the guard interval (GI) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the PPDU's bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth greater than a certain size.

In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted over at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may contain common fields and user-specific fields. Common and user-specific fields may be coded separately.

In some cases, common fields may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, common fields may be omitted, and multiple STAs may receive PPDUs (e.g., data fields of PPDUs) over the same frequency band. In a non-compressed mode where OFDMA is applied, multiple users may receive PPDUs (e.g., data fields of PPDUs) over different frequency bands.

The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field can be associated with either MU-MIMO allocation or non-MU-MIMO allocation.

The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, and the length of the Tail bits may be determined as 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

An RU can contain multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA techniques. RUs can also be defined when transmitting signals to a single STA. Resources can be allocated on an RU basis for non-legacy STFs, non-legacy LTFs, and data fields.

Depending on the PPDU bandwidth, an applicable RU size can be defined. The RU may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU arrangements of HE PPDU and EHT PPDU may be different. The applicable RU size, RU number, RU position, DC (direct current) subcarrier position and number, null subcarrier position and number, guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a low bandwidth tone plan.

RUs of different sizes can be defined, such as 26-ton RU, 52-ton RU, 106-ton RU, 242-ton RU, 484-ton RU, 996-ton RU, 2X996-ton RU, 4X996-ton RU, etc. A multiple RU (MRU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2X996+484-tons, 3X996-tons, or 3X996+484-tons. Additionally, multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.

The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. Furthermore, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs may vary depending on the RU size.

The names of each field in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by those names. Furthermore, the examples of the present disclosure can be applied not only to the PPDU format exemplified in FIG. 7, but also to a new PPDU format in which some fields are excluded and/or some fields are added based on the PPDU formats of FIG. 7.

target wake time (TWT)

Below, we explain TWT (target wake time).

TWT is a power saving technology that can improve the energy efficiency of non-AP STAs by defining a service period (SP) between an AP and non-AP STAs and sharing information about the SP to reduce contention of the medium. In the TWT setup phase, an STA that performs requests/suggestions/demands, etc., can be called a TWT requesting STA. In addition, an AP that responds to the request with an acceptance/rejection, etc., can be called a TWT responding STA. The setup phase can include a process of determining/defining a TWT request from an STA to the AP, the type of TWT operation to be performed, and the type of frames to be transmitted and received. TWT operations can be divided into individual TWT and broadcast TWT.

FIG. 8 is a drawing illustrating an example of an individual TWT operation to which the present disclosure can be applied.

Individual TWT is a mechanism in which an AP and a non-AP STA negotiate the awake/doze status of a non-AP STA by sending and receiving TWT request/response frames, and then exchange data. In the example of Fig. 8, an AP and STA1 can form a trigger-enabled TWT agreement through a TWT request frame and a TWT response frame. Here, the method used by STA1 is a solicited TWT method, in which STA1 transmits a TWT request frame to the AP, and STA1 receives information for TWT operation from the AP through a TWT response frame. On the other hand, STA2, which performs the unsolicited TWT method, can receive information about the trigger-enabled TWT agreement setup from the AP through the unsolicited TWT response. Specifically, STA2 can calculate the next TWT by adding a specific number to the current TWT value. During the trigger-enabled TWT SP, the AP can transmit a trigger frame to the STAs. The trigger frame can inform the STAs that the AP has buffered data. In response, STA1 can inform the AP of its awake state by transmitting a PS-Poll frame. Additionally, STA2 can inform the AP of its activated state by transmitting a QoS Null frame. Here, the data frames transmitted by STA1 and STA2 can be frames in the TB PPDU format. After checking the status of STA1 and STA2, the AP can transmit DL MU PPDUs to the activated STAs. When the corresponding TWT SP expires, STA1 and STA2 can transition to a doze state.

FIG. 9 is a diagram illustrating an example of a broadcast TWT operation to which the present disclosure can be applied.

Broadcast TWT is a TWT in which a non-AP STA (or TWT scheduling STA) obtains information such as target beacon transmission time (TBTT) and listen interval by transmitting and receiving TWT request/response frames with the AP (or TWT scheduled STA). Here, a negotiation operation for TBTT may be performed. Based on this, the AP can define a frame to include TWT scheduling information through a beacon frame. In Fig. 9, STA1 performs a requested TWT operation, and STA2 performs an unsolicited TWT operation. The AP can transmit a DL MU PPDU after checking the awake status of the STAs through the trigger transmitted by itself. This may be the same as the process of an individual TWT. In broadcast TWT, a trigger-enabled TWT SP including a beacon frame may be repeated multiple times at a regular cycle.

Transmission of TWT information can be accomplished through a TWT information frame and a TWT information element.

The TWT information frame is transmitted by an STA to request or convey information about a TWT agreement, and is transmitted by one of the STAs of an existing TWT agreement. The action frame of the TWT information frame includes a TWT information field. The TWT Information field may include a 3-bit TWT flow identifier subfield, a 1-bit response requested subfield, a 1-bit next TWT request subfield, a 2-bit next TWT subfield size subfield, a 1-bit all TWT subfield, and a 0/32/48/64-bit next TWT subfield.

Figure 10 is a drawing for explaining an example of a TWT information element format.

TWT information elements can be transmitted and received in beacons, probe responses, (re)association response frames, etc. The TWT information elements can include an element identifier (ID) field, a length field, a control field, and a TWT parameter information field.

The control fields of a TWT information element have the same format regardless of whether it is an individual TWT or a broadcast TWT.

The NDP paging indicator subfield can have a value of 1 if the NDP paging field exists, and a value of 0 if the NDP paging field does not exist.

The responder PM mode subfield may indicate a power management (PM) mode.

The negotiation type subfield may indicate whether the information contained in the TWT element is about negotiation of parameters of a broadcast TWT or individual TWT(s), or about a wake TBTT interval.

For example, if the negotiation type subfield has a value of 0, the TWT subfield is for a future individual TWT SP start time, and the TWT element contains one individual set of TWT parameters. This may correspond to an individual TWT negotiation between a TWT requesting STA and a TWT responding STA, or to an individual TWT announcement by a TWT responder.

For example, if the value of the Agreement Type subfield is 1, the TWT subfield is for the next TBTT time, and the TWT element contains one individual set of TWT parameters. This may correspond to the wake TBTT and wake interval negotiation between the TWT scheduled STA and the TWT scheduling AP.

For example, if the value of the Agreement Type subfield is 2, the TWT subfield is for a future broadcast TWT SP start time, and the TWT element contains one or more broadcast TWT parameter sets. This may correspond to providing a broadcast TWT schedule to a TWT-scheduled STA by including the TWT element in a broadcast management frame transmitted by the TWT scheduling AP.

For example, if the value of the Agreement Type subfield is 3, the TWT subfield is for a future broadcast TWT SP start time, and the TWT element contains one or more sets of broadcast TWT parameters. This may correspond to managing membership in a broadcast TWT schedule by including the TWT element in individually addressed management frames transmitted by either the TWT-scheduling STA or the TWT-scheduling AP.

If the TWT information frame disabled subfield is set to 1, it indicates that reception of TWT information frames by the STA is disabled, otherwise it may be set to 0.

The wake duration unit subfield indicates the unit of the nominal minimum TWT wake duration field. The wake duration unit subfield may be set to 0 if the unit is 256 us and set to 1 if the unit is TU. For non-HE/EHT STAs, the wake duration unit subfield may be set to 0.

The most significant bit (MSB) of the agreement type field may correspond to a broadcast field. If the broadcast field is 1, a TWT element may contain one or more broadcast TWT parameter sets. If the broadcast field is 0, only one individual TWT parameter set may be contained in the TWT element. A TWT element with the broadcast field set to 1 may be referred to as a broadcast TWT element.

Fig. 11 is a diagram illustrating examples of individual TWT parameter set field formats. Fig. 12 is a diagram illustrating examples of broadcast TWT parameter set field formats.

The TWT parameter information field included in the TWT element of Fig. 10 may have a different configuration depending on the individual TWT or broadcast TWT.

For individual TWTs, the TWT parameter information field within the TWT element contains a single individual TWT parameter set field.

In the case of a broadcast TWT, the TWT parameter information field within the TWT element contains one or more broadcast TWT parameter set fields. Each broadcast TWT parameter set may contain specific information about one broadcast TWT.

As illustrated in FIGS. 11 and 12, the individual TWT parameter set field and the broadcast TWT parameter set field include common subfields.

The request type subfield may be the same size as the individual TWT parameter set field and the broadcast TWT parameter set field, but may have different detailed configurations. This will be described later.

The target wake time subfield indicates the start time of the upcoming individual/broadcast TWT SP.

The nominal maximum TWT wake duration subfield indicates the minimum interval during which a TWT requesting STA expects to wake up to complete a frame exchange associated with a TWT flow identifier during the TWT wake interval duration. Here, the TWT wake interval may mean the average time between consecutive TWT SPs expected by the TWT requesting STA.

The TWT Wake Interval Mantissa subfield can be expressed as a binary value of the TWT wake interval value in microseconds.

Referring to Figure 11, the TWT group assignment subfield, TWT channel, and NDP paging subfield are included only in the individual TWT parameter set fields.

The TWT Group Assignment subfield provides the TWT requesting STA with information about the TWT group to which the STA is assigned. This information can be used to calculate the TWT value within the TWT group. The TWT value of the STA may be equal to the value of the zero offset multiplied by the value of the TWT offset multiplied by the value of the TWT unit.

The TWT Channel subfield indicates a bitmap indicating allowed channels. When transmitted by a TWT requesting STA, the TWT Channel subfield may include a bitmap indicating a channel that the STA requests to use as a temporary default channel during the TWT SP. When transmitted by a TWT responding STA, the TWT Channel subfield may include a bitmap indicating a channel on which the TWT request is allowed.

The NDP paging subfield is optional and may include information such as an identifier of the STA being paged, the maximum number of TWT wake intervals between NDP paging frames, etc.

Referring to FIG. 12, the broadcast TWT info subfield is included only in the broadcast TWT parameter set field. The broadcast TWT info subfield may include a 3-bit reserved bit, a 5-bit broadcast TWT identifier (ID) subfield, and an 8-bit broadcast TWT persistence subfield. The broadcast TWT identifier subfield indicates the broadcast ID of a specific broadcast TWT for which an STA requests participation or provides TWT parameters, depending on the value of the TWT setup command subfield of the TWT element. The broadcast TWT persistence subfield indicates the number of TBTTs planned in the schedule of the broadcast TWT.

Next, we will explain the detailed configuration of the request type subfield.

First, the format of the request type subfield of the individual TWT parameter set field is described with reference to FIG. 11.

The TWT request subfield can indicate whether the STA is a requesting STA or a responding STA. If the value is 1, it indicates that the STA is a TWT requesting STA or a scheduled STA, and if it is 0, it indicates that the STA is a TWT responding STA or a scheduling AP.

The TWT setup command subfield can represent commands such as Request, Suggest, Demand, Accept, Alternate, Dictate, and Reject.

The trigger subfield indicates whether a trigger frame is used in the TWT SP. If the value is 1, the trigger is used, and if it is 0, the trigger is not used.

The implicit subfield can indicate whether the TWT is implicit or explicit. A value of 1 indicates implicit TWT, while a value of 0 indicates explicit TWT.

The flow type subfield may indicate the type of interaction between a TWT requesting STA (or a TWT-scheduled STA) and a TWT responding STA (or an AP that schedules the TWT). If the value is 1, it may mean announced TWT, in which the STA sends a wake-up signal to the AP by transmitting a PS-Poll or APSD (automatic power save delivery) trigger frame before a non-trigger frame is transmitted from the AP to the STA. If the value is 0, it may mean unannounced TWT.

The TWT flow identifier subfield may contain a 3-bit value that uniquely identifies specific information about the TWT request in other requests made between the same TWT requesting STA and TWT responding STA pair.

The TWT wake interval exponent subfield can set the TWT wake interval value in binary microseconds. For individual TWTs, this can mean the interval between individual TWT SPs. The TWT wake interval of the requesting STA can be defined as [TWT Wake Interval Mantissa * 2 * TWT Wake Interval Exponent].

The TWT protection subfield can indicate whether a TWT protection mechanism is used. If the value is 1, TXOPs within a TWT SP can be initiated with a NAV protection mechanism, such as (MU)RTS/CTS or CTS-to-self frames. If the value is 0, the NAV protection mechanism may not be applied.

Referring to FIG. 12, some of the subfields of the request type subfield of the broadcast TWT parameter set field are common to the subfields of the request type subfield of the individual TWT parameter set fields, and therefore, a description thereof is omitted. The subfields included only in the broadcast TWT parameter set are described below.

The Last Broadcast Parameter Set subfield indicates whether this is the last broadcast TWT parameter set. A value of 1 indicates that this is the last broadcast TWT parameter set, while a value of 0 indicates that there is a next broadcast TWT parameter set.

The Broadcast TWT Recommendation subfield may indicate recommendations for the frame types transmitted by the AP during a Broadcast TWT SP, with values from 1 to 7.

The last bit of the Request Type subfield of the Broadcast TWT Parameter Set field may be reserved.

With the recent explosion in wired and wireless traffic, latency-sensitive traffic has also increased significantly. Latency-sensitive traffic includes real-time audio/video transmission, and the proliferation of multimedia devices has increased the need to support this traffic in wireless environments. However, supporting latency-sensitive traffic in wireless environments requires more considerations than in wired environments. This is because wireless environments have lower transmission speeds and must also consider interference from surrounding environments. In particular, in WLAN systems, multiple STAs must compete equally for medium access in the Industry-Science-Medical (ISM) band, making it relatively more difficult to support latency-sensitive traffic compared to cellular communication networks, which rely on centralized radio resource scheduling. This disclosure describes a novel approach for supporting latency-sensitive traffic in WLAN systems.

In the present disclosure, latency may refer to latency defined in the IEEE 802.11 series standards. For example, it may refer to the time from when a frame to be transmitted enters the queue of the MAC layer of the transmitting STA, until the transmitting STA successfully completes transmission in the PHY layer, and the transmitting STA receives an ACK/block ACK, etc. from the receiving STA, and the corresponding frame is deleted from the MAC layer queue of the transmitting STA. In addition, in the present disclosure, a non-AP STA that supports transmission of latency-sensitive data may be referred to as a low latency STA. In addition, data other than latency-sensitive data may be referred to as regular data.

Restricted TWT (r-TWT) can support securing data transmission possibility for low-latency STAs transmitting latency-sensitive data preferentially over other STAs by having the AP set a special broadcast TWT for the low-latency STAs. The STAs can establish membership in one or more r-TWT schedules with respect to the AP. Here, the r-TWT agreement can be established by the same process as the broadcast TWT agreement, and the broadcast TWT element for this can be defined to include an r-TWT parameter set field. For example, the r-TWT parameter set can refer to a specific broadcast TWT parameter set field that is distinct from other broadcast TWT parameter set fields. That is, the r-TWT parameter set field can correspond to a special case of the broadcast TWT parameter set field. In addition, the AP can announce an r-TWT SP.

Basically, if another STA supporting r-TWT operation is a TXOP holder, the TXOP must end before the start time of the r-TWT SP advertised by the associated AP. Accordingly, the STA related to the r-TWT (i.e., the low-latency STA) can transmit and receive traffic with priority over the other STAs within the r-TWT SP.

In the present disclosure, a low-latency STA associated with a specific r-TWT, as described above, is referred to as a member r-TWT scheduled STA, and other STAs are referred to as non-member STAs. A non-member STA may be an STA that has the capability to support r-TWT operation but is not a member of any r-TWT, or that supports r-TWT operation but is a member of another r-TWT, or that does not have the capability to support r-TWT operation.

An STA (e.g., a low-latency STA) that supports limited SP (or r-TWT SP) operation of broadcast TWT can inform the AP that it needs to transmit latency-sensitive data based on r-TWT operation. If the AP supports r-TWT operation/mode, the AP can transmit a frame containing scheduling information of TWTs requested by each STA to the low-latency STA and other STA(s). For example, in order to perform operation for r-TWT, non-AP STAs can obtain r-TWT related information from the AP through a beacon frame, a probe response frame, a (re)association response frame, or other frames in an undefined format (e.g., frames for broadcast, advertisement, or announcement purposes).

According to the restricted TWT operation, a separate TXOP (i.e., to which access of other STAs is restricted) can be secured within the r-TWT SP by using a NAV such as (MU) RTS/CTS or CTS-to-self, or a quiet interval. Before a specific r-TWT SP starts, if there is a TXOP of another STA (i.e., a non-member STA) other than the STA having the membership for the specific r-TWT schedule, it must be stopped. And the TXOP of the other STA (i.e., the non-member STA) can be additionally performed after the specific r-TWT SP ends.

In-Device Coexistence (IDC) Operation

Wi-Fi wireless communication technology can be used together with non-Wi-Fi wireless communication technologies in similar frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, etc.). For example, non-Wi-Fi wireless communication technologies may include various wireless communication technologies such as Bluetooth, Zigbee, and UWB (ultra wide band). A single device (e.g., a smartphone, smartwatch, AR/VR device, etc.) may support both Wi-Fi and non-Wi-Fi wireless communication technologies, and when transmission and reception according to different wireless communication technologies coexist simultaneously on the same or adjacent frequency bands, problems such as reduced transmission throughput and increased latency may occur due to mutual interference, packet loss, and rate degradation.

FIG. 13 is a diagram illustrating an example of a collision caused by an IDC to which the present disclosure can be applied.

A device (STA) may perform Wi-Fi-based transmission and reception with an AP, or may perform non-Wi-Fi-based transmission and reception with another device (e.g., a non-Wi-Fi device). For example, while an AP and an STA are performing periodic Wi-Fi-based data transmission/reception, a non-Wi-Fi-based transmission and reception between the STA and another device may occur, resulting in a collision.

For example, an AP may transmit an initial control frame (ICF) such as RTS to transmit data to an STA, and the STA may transmit an initial control response (ICR) such as CTS if it can receive data. Accordingly, the AP may begin transmitting data to the STA. Additionally, transmission and reception between the STA and a non-Wi-Fi device may occur periodically. In this case, Wi-Fi data transmission/reception may fail during a section where a non-Wi-Fi transmission/reception section collides with a Wi-Fi transmission/reception section.

Alternatively, the STA may not respond to the AP's RTS frame, considering that it expects periodic transmissions with non-Wi-Fi devices. In this case, since transmissions from non-Wi-Fi devices occur periodically for short periods of time, the problem of unfairness may arise, as Wi-Fi data from the AP, which transmits for relatively long periods of time, may not receive transmission opportunities.

To address these issues, if information about the IDC can be signaled to the other Wi-Fi device (e.g., AP) for smooth Wi-Fi-based communication, Wi-Fi communication can be performed by avoiding resources used for non-Wi-Fi communication, thereby preventing performance degradation.

This disclosure describes various examples of signaling information about an IDC of a device (in particular, information about periodically occurring IDC intervals) to another device.

Although various examples of the present disclosure are described based on a TWT setup frame including a TWT element, or a channel usage request/response frame including a channel usage element, examples in which IDC-related information according to the examples of the present disclosure is included in elements of other names (e.g., IDC elements) and/or frames of other names (e.g., IDC frames) may also be included within the scope of the present disclosure.

Furthermore, the scope of the present disclosure is not limited by the names of the fields in the examples of the present disclosure, and the examples of the present disclosure may also be applied to fields with other names. Furthermore, in the examples below, the term "field" may be replaced with "subfield," and the term "subfield" may be replaced with the term "field."

FIG. 14 is a diagram showing an example of the operation of the first STA according to the present disclosure.

In step S1410, the first STA can transmit a first frame including a first element to the second STA.

In some examples, when the first element includes a control field, a specific bit may be included within the control field of the first element that indicates whether information related to the IDC is included within the first element. For example, the specific bit may correspond to the first bit of the control field, the B0 position, or the bit position of the (existing) NDP paging indicator bit.

In some examples, information related to IDC may include information about resources related to IDC. Resources related to IDC may be specified by time resources, frequency resources, and/or spatial resources. For example, information about time resources may include a start time, an end time, a duration, a number of time units, and/or an interval. For example, information about frequency resources may include a bandwidth, a frequency range, a center frequency, a channel, and/or a resource unit. For example, information about spatial resources may include an antenna index, a number of antennas, a spatial stream index, and/or a number of spatial streams.

In some examples, information about resources related to IDC may include information about available resources and/or unavailable resources. For example, if information about available resources for time/frequency/space is indicated, unavailable resources may correspond to the remaining resources for all time/frequency/space, excluding available resources. For example, if information about unavailable resources for time/frequency/space is indicated, available resources may correspond to the remaining resources for all time/frequency/space, excluding unavailable resources. For example, information about available resources may be provided for one or more of time/frequency/space, and information about unavailable resources may be provided for another one or more of time/frequency/space.

In some examples, the information related to the IDC may include information about the PPDU duration, TXOP duration, number of MPDUs, and/or maximum modulation coding scheme (MCS) related to the IDC.

In some examples, a presence field may be included for each of one or more fields corresponding to information related to the IDC. For example, the presence field may include a bitmap, and bit positions in the bitmap may each correspond to fields corresponding to information related to the IDC.

In some examples, information related to an IDC may further include a field indicating full availability or partial availability (i.e., a field indicating whether full availability is present). Alternatively, information related to an IDC may further include a field indicating full unavailability or partial unavailability (i.e., a field indicating whether full unavailability is present). For example, if full availability or full unavailability is indicated, information related to an IDC may not include information about resources related to the IDC. Alternatively, if partial availability or partial unavailability is indicated, information related to an IDC may include information about resources related to the IDC.

In some examples, information related to IDC may further include a field indicating whether the time resource is periodic. For example, if periodicity of the time resource is indicated, information related to the IDC resource may include information on the number of time units and/or intervals. Alternatively, if aperiodicity of the time resource is indicated, information related to the IDC resource may not include information on the number of time units and/or intervals.

In step S1420, the first STA may perform an IDC operation in an IDC service period (SP) based on information included in the first element.

In some examples, the IDC operation may include performing frame transmission and reception between the first STA and the second STA during the IDC SP. Alternatively, the IDC operation may include deferring frame transmission and reception between the first STA and the second STA during the IDC SP.

Although not illustrated in FIG. 14, a second frame in response to the first frame may be transmitted from the second STA to the first STA. For example, the second frame may include a second element. The second element may include information related to the IDC. Accordingly, the IDC SP may be defined/determined based on the information included in the first element and/or the information included in the second element.

In some examples, the first element and/or the second element may be a TWT element, a channel usage element, or a modified element thereof. Alternatively, the first element and/or the second element may be a new element with a new name/format. In the case of a TWT element, as described above, whether the TWT element includes IDC-related information may be indicated through the value of a specific bit of the control field. Alternatively, the channel usage element may include a usage mode field (other than the control field of the TWT element), and a specific value of the usage mode field may indicate that the channel usage element includes information related to the IDC.

In some examples, the first frame may be a TWT setup frame, a channel use request frame, or a variant thereof, and the second frame may be a TWT setup frame, a channel use response frame, or a variant thereof. Alternatively, the first frame and/or the second frame may be new frames with a new name/format.

For example, if the first element is a TWT element, the type field of the control field (e.g., negotiation type) may be set to a value (e.g., 0) indicating that the first element includes an individual TWT parameter set field.

In the examples described above, the first STA may be a non-access point (non-AP) STA and the second STA may be an AP STA, or the first STA may be a non-AP STA and the second STA may be another non-AP STA, or the first STA may be an AP STA and the second STA may be a non-AP STA, or the first STA may be an AP STA and the second STA may be another AP STA.

The method described in the example of FIG. 14 may be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) (or the first AP) of FIG. 1 may be configured to transmit a first frame including a first element via one or more transceivers (106), and perform an IDC operation in an IDC SP based on information included in the first element. Furthermore, one or more memories (104) of the first device (100) may store commands for performing the method described in the example of FIG. 14 or the examples described below when executed by one or more processors (102).

For example, the memory (104) may store information related to various IDCs according to the present disclosure. The processor (102) may generate elements/frames for signaling information related to the IDC, generate various RUs, generate PPDUs, and transmit the generated PPDUs through the transceiver (106) based on the information stored in the memory (104). In addition, the processor (102) may generate transmission PPDUs and store information about the transmission PPDUs in the memory (104). For example, the processor (102) may be configured to perform operations of the first STA according to the examples of the present disclosure. For example, the processor (102) may be configured to determine an IDC situation, generate elements/frames/PPDUs including information related to the IDC, and transmit the elements/frames/PPDUs through the transceiver (106).

FIG. 15 is a diagram showing an example of the operation of a second STA according to the present disclosure.

In step S1510, the second STA may receive a first frame including a first element from the first STA. For example, the first element may include a specific bit (e.g., within a control field) indicating whether the first element includes information related to IDC.

In step S1520, the second STA may perform operations of the second STA related to the IDC operation by the first STA in the IDC SP based on the information included in the first element. For example, the second STA may perform frame transmission and reception with the first STA during the IDC SP. For example, the second STA may postpone frame transmission and reception with the first STA during the IDC SP.

In the example of FIG. 15, the specific description of the first frame, the second frame, the first element included in the first frame, the second element included in the second frame, the control field included in the first element and/or the second element, and/or the information related to the IDC are the same as in the example of FIG. 14, so redundant descriptions are omitted.

The method described in the example of FIG. 15 may be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 1 (e.g., the second AP) may be configured to receive a first frame including a first element via one or more transceivers (206), and perform an IDC operation of the second device (200) related to the IDC operation of the first device (100) in the IDC SP based on information included in the first element. Furthermore, one or more memories (204) of the second device (200) may store commands for performing the method described in the example of FIG. 15 or the examples described below when executed by one or more processors (202).

For example, the memory (204) can store information related to various IDCs according to the present disclosure. The transceiver (206) can receive a PPDU based on the control of the processor (202). The PPDU received through the transceiver (206) can be stored in the memory (204). For example, the processor (202) can obtain control information for bandwidth/tone-plan/RU included in the PPDU (e.g., information included in the SIG field of the PPDU) and store the obtained control information in the memory (204). The processor (202) can perform decoding on the received PPDU. For example, the processor can perform an operation of restoring the results of cyclic shift delay (CSD), spatial mapping, inverse discrete Fourier transform (IDFT)/inverse fast Fourier transform (IFFT) operation, and guard interval (GI) insertion applied to the PPDU. In addition, the processor (202) can decode the data field of the PPDU received through the transceiver (206) and process the decoded data. For example, the processor (202) can transmit information about the decoded data field to a higher layer (e.g., a MAC layer). In addition, if the generation of a signal is instructed from the higher layer to the PHY layer in response to the data transmitted to the higher layer, a subsequent operation can be performed. For example, the processor can parse the MAC PDU obtained through PHY decoding of the DATA field of the PPDU received through the transceiver (206). In addition, the processor (202) can be configured to obtain information related to the IDC and perform an operation accordingly. For example, the processor (202) of the receiving device can be configured to perform the operation of the second STA according to an example of the present disclosure. For example, the processor (202) may be configured to receive a frame containing information related to the IDC and decode/parse a frame addressed to it based thereon.

In the example of FIG. 14, the first STA may correspond to a transmitting device or an IDC SP requesting STA, and the second STA of FIG. 15 may correspond to a receiving device or an IDC SP responding STA.

A first STA may generate a first frame (e.g., an IDC SP creation request frame). The first element within the first frame may include information about time/frequency/spatial resources related to the first STA's own IDC event and/or status indication information. The first STA may transmit a PPDU including the generated frame to a second STA.

The second STA can decode the PPDU received from the first STA to obtain the first frame and the first element, and decode them. Accordingly, the second STA can obtain information related to the IDC included in the first element, and based on the information, generate a second element including response information for the IDC SP request, and generate a second frame including the second element, and transmit the second frame to the first STA via the PPDU.

If the first STA transmits the first frame and receives a response thereto from the second STA, it can be considered that an IDC SP agreement has been reached between the first STA and the second STA.

Alternatively, when operating in an unsolicited manner, the process of receiving a response from the second STA may be omitted, and the IDC SP may be established by transmitting the first frame.

The first STA may perform IDC operations during agreed/configured (periodic) IDC SPs. For example, non-Wi-Fi communications may be performed during the IDC SP without IDC interference. Alternatively, Wi-Fi and non-Wi-Fi communications may be performed on non-overlapping time/frequency/spatial resources during the IDC SP.

The second STA may not transmit or receive frames with the first STA during the IDC SP. This can prevent IDC interference from occurring during the IDC SP. Alternatively, the second STA may transmit or receive frames with the first STA based on the available time/frequency/space resources during the IDC SP.

When the IDC event of the first STA ends, the first STA may generate an IDC SP teardown frame and transmit it to the second STA. Upon receiving this IDC SP teardown frame, the second STA may confirm that the IDC event of the first STA has ended and terminate the IDC SP.

The examples of FIGS. 14 and 15 may correspond to some of the various examples of the present disclosure. Below, various examples of the present disclosure, including the examples of FIGS. 14 and 15, will be described in more detail.

In the embodiments described below, examples of the present disclosure are described assuming operations between two STAs, one IDC-supporting STA (e.g., a first STA) and a counterpart STA of Wi-Fi communication (e.g., a second STA), but the scope of the present disclosure is not limited thereto, and examples of the present disclosure can be equally applied to IDC operations and operations supporting the same between three or more STAs.

Example 1

This embodiment provides examples of basic procedures for IDC operation.

In general, IDC events can occur in smart devices such as smartphones, smartwatches, and AR/VR devices that can utilize both Wi-Fi and non-Wi-Fi technologies. Furthermore, IDC events can also occur in multi-link devices (MLDs) that support non-simultaneous transmit and receive (NSTR) operations. IDC events in these devices can also occur periodically, as in the example of FIG. 13. A device experiencing an IDC event (e.g., an STA) can notify other Wi-Fi devices (e.g., an AP) of the periodic IDC event. For this purpose, the aforementioned TWT procedure or another request/response procedure can be utilized.

FIG. 16 and FIG. 17 are diagrams showing examples of an IDC event signaling procedure according to the present disclosure.

In the example of Fig. 16, the IDC request frame may correspond to a TWT setup request of a TWT setup frame or a channel usage request frame. The IDC response frame may correspond to a TWT setup response of a TWT setup frame or a channel usage response frame. In this way, through the IDC request-response, information related to an IDC event or IDC can be exchanged between an STA and an AP. For example, the IDC-related information may include information such as the next IDC time (or IDC SP start time), duration, interval, bandwidth (or information such as channel, resource unit, multi-resource unit, distributed resource unit), IDC indication (or IDC status), and available NSS (number of spatial streams). With this IDC-related information, an STA can request the AP to create an IDC TWT SP. The AP can create an IDC SP based on the IDC information included in the request frame of STA1 and respond to STA1 with the result via a response frame. For example, at a start time specified by the following IDC time (or start time) information, a period specified by the duration information may be determined/applied as an IDC SP. This IDC SP may also be repeated periodically after an interval corresponding to the interval information. The IDC SP may correspond to a period of time during which the STA does not perform Wi-Fi communication with the AP, while the STA performs non-Wi-Fi communication with a non-Wi-Fi device.

The example of Fig. 16 corresponds to a request-response method in which a device generating an IDC transmits an IDC event or IDC-related information to another device, and the parameter(s) can be adjusted based on an agreement between the two devices. Alternatively, if the IDC event or IDC-related information does not correspond to a parameter(s) that are adjusted based on an agreement, it can be transmitted in an unsolicited manner. For example, in the example of Fig. 17, after an STA transmits an IDC setup frame containing IDC-related information to an AP in an unsolicited manner, periodic IDC SPs can be determined/applied at intervals corresponding to the interval for a period corresponding to the duration after the start time without a response from the AP. Alternatively, the AP can inform STA2 of the IDC information received from STA1 through an IDC request in an unsolicited manner through an IDC response.

The examples of FIGS. 16 and 17 are not limited to operations between non-AP STAs supporting IDC and APs, and can be equally applied to operations between an AP supporting IDC and another AP, between a non-AP STA supporting IDC and another non-AP STA, and between an AP supporting IDC and a non-AP STA.

Example 2

This embodiment relates to a signaling method for IDC related information.

TWT elements may be used to signal IDC-related information, in which case the TWT setup frame may include TWT elements corresponding to requests or responses. Alternatively, channel usage elements may be used to signal IDC-related information, in which case channel usage request frames and channel usage response frames may be used. Alternatively, new request/response frames/elements for IDC SP setup may be defined and used.

Example 2-1

Below are examples of information that may be included in IDC-related information. One or more of the following examples may be included in an element/frame containing IDC-related information and signaled/transmitted from an IDC device to another device. For example, IDC-related information may include time-domain resource-related information, frequency-domain resource-related information, spatial-domain resource-related information, IDC indication information, IDC transmission-related information, etc.

Information related to time (domain) resources can also be referred to as information about IDC SPs. For example, information related to time resources can include information such as unavailability duration, interval, and start time due to the occurrence of an IDC event or an IDC status. Alternatively, information related to time resources can include information such as availability duration, interval, and start time due to the occurrence of an IDC event or an IDC status. When information related to available time resources is provided, resources other than available time resources among the total time resources may correspond to unavailable time resources. When information related to unavailable time resources is provided, resources other than unavailable time resources among the total time resources may correspond to available time resources.

Frequency (domain) resource related information may include information on available frequency areas, channel resource units, etc. due to occurrence of an IDC event or an IDC state. Alternatively, frequency (domain) resource related information may include information on unavailable frequency areas, channel resource units, etc. due to occurrence of an IDC event or an IDC state. When information on available frequency resources is provided, resources other than available frequency resources among the entire frequency resources may correspond to unavailable frequency resources. When information on unavailable frequency resources is provided, resources other than unavailable frequency resources among the entire frequency resources may correspond to available frequency resources.

The spatial (domain) resource related information may include information such as an available antenna index, the number of available antennas, an available spatial stream index, the number of available spatial streams, and the maximum number of available spatial streams due to an IDC event occurrence or an IDC state. Alternatively, the spatial (domain) resource related information may include information such as an unavailable antenna index, the number of unavailable antennas, an unavailable spatial stream index, the number of unavailable spatial streams, and the maximum number of unavailable spatial streams due to an IDC event occurrence or an IDC state. When information related to available spatial resources is provided, resources other than available spatial resources among the entire spatial resources may correspond to unavailable spatial resources. When information related to unavailable spatial resources is provided, resources other than unavailable spatial resources among the entire spatial resources may correspond to available spatial resources.

IDC instruction information may correspond to information indicating whether the state is IDC or not.

IDC transmission related information may include information about maximum PPDU duration (or a limit on PPDU duration), maximum TXOP duration (or a limit on TXOP duration), maximum number of MPDUs (or a limit on the number of MPDUs), and maximum MCS (or a limit on MCS).

Example 2-2

Various methods for signaling elements containing IDC-related information as described above are described below.

For example, in order to include an element containing IDC-related information (e.g., referred to as an IDC TWT element) in a TWT setup frame, a new order (e.g., a value of 5) can be added/defined following the TWT element of order 4 of the existing TWT setup frame, as shown in the table below.

Order information 1 Category 2 Unprotected S1G Action 3 Dialog Token 4 One or more TWT elements 5 One or more IDC TWT elements

In this case, the IDC TWT element can be defined by reusing the field format of the existing TWT element. Alternatively, the IDC TWT element can be newly defined. Accordingly, the exchange of TWT elements for the TWT SP and the exchange of IDC TWT elements for the IDC TWT SP corresponding to the unavailable or available interval for the IDC operation can be performed simultaneously (i.e., through a single frame).

As another example, the IDC TWT elements included in the TWT setup frame may be defined as modified TWT elements as shown in the table below. In this case, the IDC TWT setup frame may correspond to a frame for setting up an IDC TWT SP.

Order information 1 Category 2 Unprotected S1G Action 3 Dialog Token 4 One or more IDC TWT elements

As another example, IDC related information may be signaled via channel usage request/response frames.

FIG. 18 is a diagram illustrating exemplary formats of channel usage elements according to the present disclosure.

In the example of Fig. 18(a), the channel entry field may be defined to contain information about available/unavailable channels related to IDC operation.

The example of Fig. 18(b) corresponds to an example of adding an IDC information field following a channel entry field of (zero or more) 2n octets in size in the existing channel usage element format. The channel entry field includes information about available or unavailable channels (or frequency resources) related to the IDC operation, and the IDC information field may include information other than information about the channel (or frequency resource) (e.g., time resource information, spatial resource information, etc.).

The example of Fig. 18(c) may correspond to an example of replacing the channel entry field in the existing channel usage element format with a variable-length IDC information field.

These channel usage elements may be defined as mandatory for devices supporting IDC. Channel usage requests/responses may be applied to various combinations of STA roles: AP-to-AP, non-AP STA-to-AP, non-AP STA-to-AP STA, or non-AP STA-to-non-AP STA.

The values 0 to 5 in the Usage Mode field indicate predefined usage modes, while values 6 to 254 are reserved. One of the previously reserved values can be newly defined to indicate (periodic) IDC. For example, if the value of the Usage Mode field is set to 6, (periodic) IDC is indicated and an IDC information field may be included.

Additionally or alternatively, IDC information may be included in channel usage request/response frames rather than channel usage elements.

FIG. 19 is a diagram showing an exemplary format of a channel use request frame according to the present disclosure.

If the channel usage element field contains IDC information (e.g., the example of FIG. 18(b) or FIG. 18(c)), the IDC information field of the channel usage request frame may be omitted.

If the channel usage element includes available or unavailable channel information and does not include IDC information (e.g., the example of FIG. 18(a)), the IDC information field of the channel usage request frame may include the remaining information (e.g., time resource information, spatial resource information, etc.) other than the IDC channel information.

Example 2-3

Below, a method for distinguishing an IDC TWT element containing IDC information from a conventional TWT element is described.

In the case of the existing individual TWT elements described with reference to FIGS. 10 and 11, the NDP paging indicator field (also referred to as the NDP paging indicator/unavailability mode field) in the first bit position (i.e., B0) of the control field is defined to be set to a value of 0. In the present disclosure, by using an individual TWT element and setting the value of the NDP paging indicator field to 1, it can be newly defined to implicitly indicate that the TWT element is an IDC TWT element.

Therefore, the first bit position (i.e., B0) of the control field of the TWT element may also be referred to as the NDP paging indicator/unavailability mode/IDC information indicator field.

FIG. 20 is a diagram illustrating an exemplary format of an IDC TWT element according to the present disclosure.

Descriptions of fields that overlap with the example of Fig. 10 in the format of the TWT element and the format of the control field of the TWT element are omitted. Meanwhile, unlike the example of Fig. 10 where the last two bits of the control field are reserved, the link ID bitmap presence field of B6 may be added.

The bit at position B0 of the control field may be modified to the NDP paging indicator/unavailability mode/IDC information indicator field, or may be newly defined as the IDC information indicator field (Fig. 20(b)).

Additionally or alternatively, the negotiation type field of the control field, as shown in Fig. 20(b), may be redefined as an IDC type field. For example, a value of 0 in the IDC type field indicates an individual ID, a value of 1 indicates a broadcast IDC, and values of 2 and 3 may be reserved.

Additionally or alternatively, for IDC TWT elements, the value of the IDC Information Indicator field may be set to 1, and the value of the Agreement Type field (Figure 20(a)) may be set to 0. In this way, by setting the value of the Agreement Type field to 0, individual TWT elements may be reused for IDC TWT purposes.

Example 2-4

FIG. 21 illustrates examples of an IDC TWT parameter set format including IDC information according to the present disclosure.

In the examples of Fig. 21, descriptions of fields that overlap with the existing individual TWT parameter set of Fig. 11 are omitted. The link ID bitmap field can indicate a link through which a TWT element is transmitted by an STA belonging to an MLD.

In the examples described below, when the IDC information field includes channel information, the TWT channel field within the TWT parameter set may be omitted or reserved. Here, omission may refer to cases where the position of the field itself does not exist and is used by another field, and reservation may refer to cases where the position of the field exists and is not used for another purpose.

Figure 21(a) illustrates an example in which the existing NDP paging field is replaced with an IDC information field. The size of the IDC information field may be 0 octets (if not included) or 2 octets (if included). Alternatively, like the existing NDP paging field, the size of the IDC information field may be 0 or 4 octets.

Figure 21(b) shows an example in which the existing NDP paging field is replaced with an IDC information field, and its size is changed to a variable size.

Figure 21(c) shows an example in which IDC information is additionally defined in the existing individual TWT parameter set field format and the NDP paging field is reserved.

Fig. 21(d) illustrates an example in which the existing TWT group assignment field is replaced with an IDC information field. In addition, the size of the IDC information field may be defined as 0 or variable, unlike the size of the existing TWT group assignment field, which is 0, 3, or 9 octets. Alternatively, the size of the IDC information field may be 0, 3, or 9 octets, similar to the size of the TWT group assignment field.

In Fig. 21(e), the last field position of the existing individual TWT parameter set field format can be replaced with an IDC information field of 0 or variable size.

Figure 21(f) illustrates the format of a newly defined IDC TWT parameter set field, including IDC information, excluding the fields reserved in the examples described above. The TWT channel field is also omitted in this example, assuming that the IDC information field includes channel information.

Example 2-5

Examples of the request type field are described in examples of the IDC TWT parameter set field of Example 2-4.

FIG. 22 illustrates examples of the format of a request type field within an IDC TWT parameter set field containing IDC information according to the present disclosure.

In the examples of Fig. 22, descriptions of fields that overlap with the fields in the request type field of the existing individual TWT parameter set field of Fig. 11 are omitted. In the examples of Fig. 22, the TWT request field of Fig. 11 is replaced with a fully unavailability field, the TWT setup command field of Fig. 11 is replaced with an IDC setup command field, and the remaining fields of Fig. 11 may be maintained the same (Fig. 22(a)) or reserved (Fig. 22(b)).

The Total Unavailability field can indicate whether the IDC provisioning form is total or partial.

For example, if the value of the overall unavailability field is 1, it may indicate that the entire time interval (e.g., duration or IDC SP) specified by the IDC-related information is unavailable. In the case of overall unavailability, information other than time resource information (e.g., start time, duration, interval, etc.) (e.g., frequency resource information, spatial resource information, transmission-related information, etc.) may be omitted.

For example, if the value of the overall unavailability field is 0, it may indicate that the time/frequency/spatial resources specified by the IDC-related information are partially unavailable (i.e., some are available). For example, during the entire time interval (e.g., duration or IDC SP), some channels/subchannels may be unavailable while other channels/subchannels may be available (i.e., Wi-Fi frame transmission and reception may be permitted). For example, within the entire time interval, some time intervals may be unavailable while other time intervals may be available. In this case, partial unavailability may be indicated when some of the time/frequency/spatial resources are available while others are unavailable.

Alternatively, even if the overall unavailability field indicates partial unavailability, each IDC SP (e.g., if the IDC SP repeats periodically, then at each repeat) may check whether the IDC SP is available through an ICF transmission (or an ICF and ICR exchange) and Wi-Fi frame transmission and reception may be performed within the IDC SP.

The names of the aforementioned full unavailability fields are exemplary and are not limiting. For example, fields named "full availability field," "partial unavailability field," and "partial availability field" may be defined. These fields may indicate whether time/frequency/spatial resources identified by IDC-related information are fully or partially unavailable (or available). For example, if defined as a partial availability field, a value of 0 may correspond to full unavailability, and a value of 1 may correspond to partial availability.

In the examples described above, time intervals other than the unavailable time intervals may correspond to available time intervals. For example, an IDC SP based on IDC-related information may be available during the IDC SP duration, and the time outside of the IDC SP may correspond to unavailable time.

Next, the IDC setup command field can have values from 0 to 7, and the meaning of each value can be defined as follows.

value meaning 0 request 1 update 2 Suspension 3 teardown 4-7 reserved

If the value of the IDC setup command field is 0, the command may request an IDC individual TWT. If the value is 1, the command may update an existing IDC SP. If the value is 2, the command may suspend (or suspend) an existing IDC SP. If the value is 3, the command may tear down (or terminate) an existing SP. If a TWT teardown frame is defined, the value 3 in the IDC setup command field may be reserved.

Depending on the command corresponding to each value, an ID of a TWT containing IDC SP(s) may be assigned using a TWT flow identifier. Accordingly, the IDC SP(s) may be managed (i.e., setup commands for the corresponding IDC SP(s) may be directed and applied) by the TWT ID.

Example 2-6

Examples of the IDC information field are described in examples of the IDC TWT parameter set field of Example 2-4.

Figure 23 illustrates an exemplary format of an IDC information field according to the present disclosure.

Some or all of the subfields of FIG. 23 may be included in the IDC information field, and other subfield(s) not shown may also be included. Furthermore, the order/position and size of the subfields of FIG. 23 are exemplary, and other orders/positions and sizes may be applied.

The length subfield may be set to a value indicating the total length of the IDC information (or the size of the remaining subfields excluding the size of the length subfield). The size of the subfields within the IDC information field may be defined variably, or the length subfield may be used to support forward compatibility.

A control subfield may contain information indicating the presence of a subfield within a parameter set field (or IDC information field). Some or all of the subfields included in the control subfields may be included in the control subfields, and other subfield(s) not shown may also be included, and the order/position and size may not be limited.

The start time subfield can be set to a value indicating the time interval from the current time to the time when the IDC SP starts, in a given unit (e.g., microseconds (ms), timing synchronization function (TSF), partial TSF, etc.).

The Duration subfield can be set to a value corresponding to the duration of the IDC SP. For example, the duration unit can be microseconds, or another unit can be applied. The size of the Duration subfield can be defined to be less than 8 octets (e.g., 2 octets), depending on the application to which the IDC SP is applied.

The Interval subfield may be set to a value indicating the time interval between repetitions of the IDC SP, when the IDC SP is repeated periodically. For example, the interval unit may be microseconds, or another unit may be applied. The size of the Interval subfield may be defined to be less than 3 octets (e.g., 2 octets), depending on the application to which the IDC SP is applied.

Time domain information such as the start time, duration, and interval mentioned above may be explicitly included in the IDC information field. Alternatively, if the start time and length of the IDC SP are indicated by TWT parameters (e.g., target wake time, TWT wake interval index, TWT wake interval mantissa, nominal minimum TWT wake duration field, etc.), time domain information such as the start time, duration, and interval may be omitted from the IDC information field. Alternatively, if time domain information such as the start time, duration, and interval are explicitly included in the IDC information field, TWT parameters (e.g., target wake time, TWT wake interval index, TWT wake interval mantissa, nominal minimum TWT wake duration field, etc.) may be reserved.

The BW subfield may be set to a value indicating available or unavailable bandwidth due to an IDC event or an IDC condition. For example, the available/unavailable bandwidth may be indicated by the start frequency and end frequency of the BW, or by the center frequency and frequency bandwidth (i.e., size) of the BW. Alternatively, the available/unavailable bandwidth may be indicated via the RU allocation subfield. For example, in an IDC situation, a frequency band used for non-Wi-Fi communication may be converted to a resource unit (RU) allocation based on the Wi-Fi operating bandwidth. The RU allocation subfield may indicate a specific combination among predetermined combinations regarding which size RU (e.g., 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 996-tone RU)(s) is allocated to which frequency position (or RU index)(s). Accordingly, frequency unit(s) of a certain size at a certain frequency location(s) can be indicated as available/unavailable bandwidth due to IDC operation.

The BW type subfields within the BW subfield can be defined as shown in the table below. Some or all of the types in the examples can be defined, and other type(s) can be added.

value meaning 0 frequency range 1 center frequency 2 resource unit 3 reserved

If the value of the BW type is 0, it can indicate that the second subfield within the BW subfield corresponds to the start frequency and the third subfield corresponds to the end frequency. For example, if the value of the start frequency is 2400, it can be indicated as approximately 2.4 GHz (= 2400 * 106 Hz), and if the value of the end frequency is 2483, it can be indicated as approximately 2.48 GHz (= 2483 * 106 Hz).

If the value of the BW type is 1, it can indicate that the second subfield within the BW subfield corresponds to the center frequency and the third subfield corresponds to the frequency bandwidth. For example, if the value of the center frequency is 7987, it can be indicated as approximately 7.9 GHz (= 7987 * 10 6 Hz), and if the value of the frequency bandwidth is 500, it can be indicated as approximately 0.5 GHz (= 500 * 10 6 Hz).

If the value of the BW type is 2, it can indicate that the second subfield within the BW subfield corresponds to BW and the third subfield corresponds to the RU allocation subfield. For example, if the value of the second subfield BW is 0, it can indicate 20MHz, if the value is 1, it can indicate 40MHz, if the value is 2, it can indicate 80+80MHz or 160MHz, if the value is 3, it can indicate the first 320MHz (i.e., the 320MHz bandwidth of the lower frequency), if the value is 4, it can indicate the second 320MHz (i.e., the 320MHz bandwidth of the higher frequency), and the remaining values can be defined as reserved. Accordingly, the value of the third subfield, the RU allocation subfield, can indicate one of the combinations of RU sizes and positions (or indices) that are predetermined for each BW.

If the TWT channel field among the TWT parameters indicates an available channel or an unavailable channel for the IDC, the BW subfield within the IDC information field may be omitted.

The Available NSS subfield can indicate the number of available spatial streams. Depending on the value of the Available NSS subfield, the number of available spatial streams can be indicated even in an IDC situation, excluding spatial streams that are unavailable due to an IDC event or IDC situation.

Example 2-7

This embodiment relates to information that may be additionally included in IDC-related information (or the IDC information field). Some or all of the following information may be included: IDC continuity, IDC channel/BW, and IDC NSS/antenna information.

IDC continuity information can indicate how long an IDC SP lasts. For example, the number of IDC SP repetitions (e.g., an integer value) can be indicated as IDC continuity information.

Additionally or alternatively, as IDC continuity information, the entire duration including all IDC SP repetitions from the start time of the IDC SP (i.e., the duration until the end of the IDC SP repetitions, not the duration of one IDC SP) or the end time of the IDC SP repetitions (i.e., the point in time when the IDC SP repetitions end, not the end time of one IDC SP) may be indicated.

Alternatively, the number of beacon frames, TBTT, beacon interval, etc. may be indicated as IDC continuity information. For example, the number of times a beacon is transmitted within a period in which repetition continues from the time when the IDC SP is first generated/started may be indicated. Alternatively, the number of beacon intervals for which repetition of the IDC SP continues in units of beacon intervals from the time when the IDC SP is first generated/started may be indicated.

This IDC continuity information may be included in the IDC information when an IDC interval exists (i.e., when a predetermined interval exists between repetitions of the IDC SP).

Next, IDC channel/BW information can indicate frequency resources on which IDC SPs may or may not occur.

For example, IDC channel/BW information can be defined in bitmap format. For example, for the operating channel and/or bandwidth of an STA, a bitmap in units of 20MHz (sub)channels can be defined, and whether each 20MHz (sub)channel is available or unavailable due to an IDC event can be indicated through the value of each bit position in the bitmap.

Additionally or alternatively, since the BW of each STA may be different, BW information may be additionally indicated. For example, the BW may be indicated as one of 20MHz/40MHz/80MHz/160MHz/320MHz, and a bitmap having a number of bits corresponding to the number of 20MHz (sub)channels corresponding to the indicated BW may be adaptively configured.

IDC channel/BW information may indicate a limited BW within which an STA can transmit and receive (i.e., available) due to an IDC situation, in which case information about the IDC channel may not be included in the IDC-related information.

Next, information indicating available (or unavailable) NSS and/or available (or unavailable) antenna indices may be included. Accordingly, available or unavailable NSS and/or antenna indices in an IDC situation may be indicated. For example, the availability/unavailability of each antenna may be indicated bit by bit, starting from the lowest (or highest) antenna index, based on the most significant bit (MSB) or least significant bit (LSB) of the corresponding subfield.

Example 2-8

The information/fields/subfields of the various examples described above may vary depending on the situation in which they are included in the IDC-related information. For example, if the primary channel of the BSS to which the STA belongs is affected by an IDC event, the STA may not be able to use all channels within the BSS due to the IDC operation, and therefore the IDC channel/BW information indicating specific frequency resources may not be included in the IDC-related information. Alternatively, if the entire spatial stream or the entire operating channel of the STA is affected and cannot be used due to the IDC operation, the IDC channel/BW information and available NSS information may not be included in the IDC-related information. Alternatively, if the IDC SP does not repeat periodically but occurs only temporarily once, the IDC interval information and IDC continuity information may not be included in the IDC-related information. Therefore, various methods described below may be applied to indicate whether specific information/fields/subfields are included (or exist) in the IDC-related information.

Figure 24 illustrates additional examples of IDC information fields according to the present disclosure.

For example, a presence field can be defined and used for each piece of information/field/subfield. If the value of the presence field for a specific piece of information is 1, the specific piece of information exists, and if the value is 0, the specific piece of information may not exist.

The presence field may also be defined in bitmap form. For example, in the example of FIG. 23, B0 to B7 in the control subfield may correspond to an example of the presence bitmap. As in the example of FIG. 24(a), it may be assumed that the first bit of the presence bitmap corresponds to IDC start time information, the second bit corresponds to IDC duration information, and the third bit corresponds to IDC channel information. When the presence bitmap is set to 110xxxxx, the IDC information may include the IDC start time field and the IDC duration field, but may not include the IDC channel field. In the presence bitmap, the remaining bits except for the number of bits corresponding to each piece of information may be reserved.

Next, the 1-bit full unavailability field in the examples of FIG. 22 may also indicate whether other information is included. As described above, if full unavailability is indicated (e.g., if the value of the full unavailability field is set to 1), other fields such as the IDC channel may not be included in the IDC-related information. Alternatively, if partial unavailability (or partial availability) is indicated (e.g., if the value of the full unavailability field is set to 0), other fields such as the IDC channel may be included in the IDC-related information.

Next, a 1-bit indication field may be defined and utilized to indicate periodicity. If the IDC SP is periodic and continuously repeats, the value of the periodicity field may be set to 1. If the IDC SP is generated only once, the value of the periodicity field may be set to 0. In this case, IDC interval information and IDC continuity information may not be included in the IDC-related information.

In the example of Fig. 24(b), if the value of the entire unavailable field is 0, it means that some of the data is unavailable (or partially available), and thus information such as IDC channels may be included. In addition, if the value of the periodicity field is 0, it means that the data corresponds to a non-repeating IDC SP, and thus the IDC start time and IDC duration fields are included, but the IDC interval and IDC continuity fields may not be included.

In the example of Fig. 24(c), a length field may be added to the IDC information field. When a new subfield is added to the IDC information, an STA that cannot recognize the new subfield may determine which field to ignore based on the value of the length field.

Additionally or alternatively, an IDC information field may be assigned an ID. This is to explicitly indicate that the field is an IDC information field, and any other ID value may be recognized by the STA as not being an IDC information field.

As shown in the example of Fig. 24(d), a generalized control information field may include one or more control information. For example, a general control information field may include the same control information or different control information. For example, an IDC information field and another information field may be included within a general control information field. The first field of the general control information field may indicate the number of control information, and for example, it may be assumed that two pieces of control information are included. It is assumed that an ID value of 0 is assigned to an IDC information field and an ID value of 1 is assigned to a BSR (buffer status report) information field. Therefore, an IDC information field including an ID field set to a value of 0 and a BSR information field including an ID field set to a value of 1 may be included within the general control information field.

Alternatively, the number field of control information may be omitted in the example of Fig. 24(d). Alternatively, the number field of control information may be configured in the form of an element that includes a length field.

FIG. 24(e) illustrates an example in which the aforementioned IDC information fields are included in an aggregated-control (A-control) field within the HT (high throughput) control field of the MAC header. The A-control field may be included in a QoS data frame, a QoS null frame, a management frame, etc. The A-control field may include various control information and may be distinguished through a control ID assigned to each of the various control information. Assuming that a control ID is assigned to the IDC information, various IDC-related information described above may be included following this control ID field. Subsequently, other control information (if any) may be included within the A-control field. After the various control information within the A-control field is included, padding bits may be added if necessary to match a specific length.

Example 3

This embodiment describes examples of signaling IDC-related information and performing IDC operations accordingly.

FIG. 25 illustrates an example of a periodic IDC SP according to an IDC request and IDC response exchange according to the present disclosure.

When an IDC event/situation occurs at an STA, it can send an IDC request (e.g., an IDC TWT request or a channel use request) to the AP. The AP can configure/create an IDC SP based on the IDC request and transmit an IDC response (e.g., an IDC TWT response or a channel use response). The configured IDC SP starts a predetermined time after the IDC response and can be repeated periodically based on the duration of each repetition and the interval between repetitions.

An STA can indicate IDC information using a TWT setup frame for an IDC request. A TWT setup frame for an IDC request can be structured as follows.

Order information Example values explanation 1 Category 22 Unprotected S1G 2 Unprotected S1G Action 12 IDC TWT setup 3 Dialog Token Any value According to the implementation example 4 One or more TWT elements Variable TWT elements

The TWT element format may follow the example of Figure 20, and the element ID may be set to a value of, for example, 216.

The control fields of the TWT element may follow the example of (b) of FIG. 20, wherein the IDC Information Indicator field is set to a value of 1, the IDC Type field is set to a value of 0 (i.e., indicating that the IDC includes a set of individual TWT parameters), the Wake Duration Unit field is set to a value of 0 (i.e., indicating that the unit is 256 ms), and the Link ID Bitmap Present field is set to a value of 0 (i.e., indicating that it is not an MLD device) or may be reserved.

The individual TWT parameter set field may follow the example of (f) of FIG. 21, wherein the target wake time field is set to a value corresponding to the start time of the IDC SP based on the TSF (e.g., 0x7F123456789012), the nominal minimum TWT wake duration field is set to a value corresponding to the wake duration of the IDC SP (e.g., 10) (i.e., since the wake duration unit is 256 ms, an IDC SP duration of 2.56 ms is indicated), and the TWT wake interval mantissa field may be set to a value of 1000 (i.e., if the value of the TWT wake interval exponent field is 8, it is combined with the value of the mantissa field to apply 256000 (=1000*2 ⁸ ), i.e., 256 ms, as the TWT wake interval value). The individual TWT parameter set field may not include a link ID bitmap (since the value of the link ID presence field is 0), and may further include a request type, a TWT channel field, and an IDC information field, as in other examples of FIG. 20.

The request type field may follow the example of (b) of FIG. 22, wherein the value of the total unavailability field is set to 0 (i.e., indicating partial unavailability or partial availability), the IDC setup command is set to a value of 0 (i.e., indicating a request), the TWT flow identifier field is set to a value of 1, and the TWT wake interval index field may be set to a value of 8.

The IDC information field may follow the example of FIG. 23. The start time presence, duration presence, interval presence, BW presence, and available NSS presence fields of the control subfield of the IDC information field may all be set to 1. Although not shown in FIG. 23, an IDC indication presence field may be further included in the control subfield within the IDC information field, and when its value is 1, the IDC indication field may be included within the IDC information field (e.g., between the interval field and the BW field).

The length field in the IDC information field is set to a value corresponding to 15 octets, the start time field is set to a value corresponding to 3000 (= 3 ms), the duration field is set to a value corresponding to 2000 (= 2 ms), the interval field is set to a value corresponding to 10000 (= 10 ms), the IDC indication field is set to a value of 1 (i.e., indicating the occurrence of an IDC event or an IDC situation), and the value of the available NSS field can be set to 2.

The BW type field within the BW field within the IDC information field may be set to a value of 0 (i.e., indicating the frequency range type), the start frequency field may be set to a value corresponding to 2400, and the end frequency field may be set to a value corresponding to 2483.

Referring back to FIG. 25, the IDC individual TWT parameters included in the IDC response may be identical to the IDC individual TWT parameters transmitted from the STA to the AP. Since the IDC operation is performed by the STA, rather than the AP rescheduling the unavailability time of the STA requesting the IDC SP, the AP may generate/configure an IDC SP that periodically repeats the unavailability time requested by the STA. After the IDC response is transmitted, the AP recognizes that the STA is unavailable for the duration from the time specified by the start time, and may postpone frame exchange with the STA during the corresponding time interval. On the other hand, since the STA is available during the interval, the AP may schedule frame exchange with the STA during the corresponding interval.

Figure 26 illustrates an example of a periodic IDC SP according to an unsolicited IDC setup according to the present disclosure.

When an unsolicited IDC setup frame is transmitted from an STA to an AP, an IDC SP can be set up/created without a response from the AP.

For example, when an IDC event changes, the STA can transmit the IDC setup command field with the value set to 1 (i.e., indicating an update).

For example, when an IDC event is paused, the STA can transmit an IDC setup command field with the value set to 2 (i.e., indicating a suspension). For example, when a Bluetooth audio streaming corresponding to an IDC event is paused, the STA can transmit an IDC setup frame to the AP notifying that the IDC SP is suspended. When resuming a suspended IDC event, the STA can resume the IDC SP by setting the value of the IDC setup command field to 1 (i.e., indicating an update) and transmitting the updated IDC information in the IDC TWT element.

For example, when an IDC event ends, the STA can transmit the IDC setup command field with the value set to 3 (i.e., indicating dismantling).

As described above, by setting frequency resource information such as BW and/or spatial resource information such as the number of NSSs together with time domain information in the IDC information or IDC individual TWT parameter set field, AP and STA can also exchange frames using other available frequency/spatial resources through consultation even during IDC SP.

The above-described examples are merely examples of the various IDC-related information described in the present disclosure, and IDC-related information may be transmitted/exchanged via other information/fields/subfields. For example, the start time, duration, and interval of the IDC information may be indicated using time-related information (e.g., target wake time, TWT wake interval, nominal minimum TWT wake duration, etc.) within an existing TWT element, and in this case, the fields for the start time, duration, and interval may be omitted/reserved within the IDC information field.

Figure 27 illustrates another example of a periodic IDC SP according to an unsolicited IDC setup according to the present disclosure.

The IDC SP, generated/configured based on the IDC-related information transmitted by the STA to the AP, can be defined/used as available time. Accordingly, any time interval (i.e., interval) other than the IDC SP period may be considered unavailable time.

Although the example in Fig. 27 illustrates an unsolicited IDC SP setup, even in cases where (periodic) IDC SPs are created/set up based on the exchange of IDC requests and IDC responses, as in the example in Fig. 25, the IDC SPs may be defined/used as available time, and other time periods (i.e., intervals) may be defined/used as unavailable time.

In the existing wireless LAN system, there is no method to support IDC operation, and by setting the IDC SP period as an unavailable time (or available time) based on the IDC-related information according to the present disclosure, a new effect can be achieved in which non-Wi-Fi transmission and reception and Wi-Fi transmission and reception are efficiently performed without interference.

The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and/or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on/in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and/or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments/containers.

The method proposed in this disclosure is described with a focus on examples applied to IEEE 802.11-based systems, but can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims (23)

A step of transmitting a first frame including a first element to a second STA by a first station (STA); and A step of performing an IDC operation by the first STA in an in-device coexistence (IDC) service period (SP) based on information included in the first element, A method wherein, based on the first element including a control field, a specific bit of the control field indicates whether the first element includes information related to IDC. In the first paragraph, The above specific bit corresponds to the first bit of the control field, the B0 position, or the NDP paging indicator bit. In the first paragraph, Information related to the above IDC includes information on resources related to the IDC, The above resources are: A time resource that includes one or more of a start time, an end time, a duration, a number of time units, or an interval; A frequency resource comprising one or more of a bandwidth, a frequency range, a center frequency, a channel, or a resource unit; or A spatial resource including one or more of an antenna index, a number of antennas, a spatial stream index, or a number of spatial streams. A method comprising one or more of: In the third paragraph, A method wherein information about resources related to the IDC includes at least one of available resources and unavailable resources. In paragraph 4, Based on the information about the above available resources, the unavailable resources correspond to the remainder of the total resources excluding the available resources, or A method in which, based on the information about the unavailable resources indicated, the available resources correspond to the remainder of the total resources excluding the unavailable resources. In the first paragraph, A method in which the information related to the IDC includes at least one of a PPDU (physical layer protocol data unit) duration, a TXOP (transmission opportunity) duration, a number of MPDU (medium access control protocol data units), or a maximum MCS (modulation coding scheme) related to the IDC. In the third paragraph, A method comprising a presence field for each of one or more fields corresponding to information related to the IDC. In paragraph 7, The above existence field contains a bitmap, A method in which the bit positions of the above bitmap each correspond to fields corresponding to information related to the IDC. In the third paragraph, A method wherein the information related to the IDC further includes a field indicating full availability or partial availability, or a field indicating full unavailability or partial unavailability. In paragraph 9, Based on the indication of the above total availability or the above total unavailability, the information related to the IDC does not include information about resources related to the IDC, A method wherein, based on the indication of some availability or some unavailability, the information related to the IDC includes information about resources related to the IDC. In the third paragraph, A method wherein the information related to the IDC further includes a field regarding the periodicity of the time resource. In paragraph 11, Based on the periodicity of the above time resource being indicated, information about the resource related to the IDC includes information about one or more of the number of time units or the interval, A method in which information about resources related to the IDC does not include information about the number of time units or the interval, based on the indication of aperiodicity of the time resource. In the first paragraph, The above IDC operation is: Performing frame transmission and reception between the first STA and the second STA during the IDC SP, or Deferring frame transmission and reception between the first STA and the second STA during the IDC SP A method comprising: In the first paragraph, A second frame responding to the first frame is transmitted from the second STA to the first STA, The second frame includes a second element, A method wherein the IDC SP is based on at least one of the information included in the first element or the information included in the second element. In paragraph 14, The first frame and the second frame are target wake time (TWT) setup frames, A method wherein the first element and the second element are TWT elements. In paragraph 15, A method wherein the type field of the above control field is set to a value indicating that the first element includes an individual TWT parameter set field. In paragraph 14, The above first frame is a channel usage request frame, The above second frame is a channel usage response frame, The first element and the second element are channel usage elements, A method wherein the first channel usage element includes a usage mode field, and a specific value of the usage mode field indicates that the channel usage element includes information related to the IDC. In the first paragraph, The first STA is a non-access point (non-AP) STA, and the second STA is an AP STA, or The first STA is a non-AP STA and the second STA is another non-AP STA, or The first STA is an AP STA and the second STA is a non-AP STA, or A method wherein the first STA is an AP STA and the second STA is another AP STA. one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Transmitting a first frame including a first element to a second station (STA) via one or more transceivers; and It is set to perform IDC operation in the device-in-device coexistence (IDC) service period (SP) based on the information included in the first element above, A first STA, wherein the first element includes a control field, wherein a specific bit of the control field indicates whether the first element includes information related to in-device coexistence (IDC). A step of receiving a first frame including a first element from a first STA by a second station (STA); and A step of performing an operation of the second STA related to an IDC operation by the first STA in an in-device coexistence (IDC) service period (SP) based on information included in the first element, A method wherein, based on the first element including a control field, a specific bit of the control field indicates whether the first element includes information related to in-device coexistence (IDC). one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Receiving a first frame including a first element from a first station (STA) through one or more transceivers; and It is set to perform an operation of the second STA related to an IDC operation by the first STA in an in-device coexistence (IDC) service period (SP) based on information included in the first element, A second STA, wherein a specific bit of the control field indicates whether the first element includes information related to in-device coexistence (IDC). one or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 18 based on execution by said one or more processors. One or more non-transitory computer-readable media storing one or more instructions that control execution by one or more processors to perform a method according to any one of claims 1 to 18.