Patent Application
20250141643
The present disclosure relates to a wireless local area network (WLAN) system, and more specifically to a method and device for transmitting and receiving null-data packet (NDP) feedback report response in a WLAN system.
New technologies for improving transmission rates, increasing bandwidth, improving reliability, reducing errors, and reducing latency have been introduced for a wireless LAN (WLAN). Among WLAN technologies, an Institute of Electrical and Electronics Engineers (IEEE) 802.11 series standard may be referred to as Wi-Fi. For example, technologies recently introduced to WLAN include enhancements for Very High-Throughput (VHT) of the 802.11ac standard, and enhancements for High Efficiency (HE) of the IEEE 802.11ax standard.
In order to provide a more improved wireless communication environment, an enhancement technologies for EHT (Extremely High Throughput) are being discussed. For example, technologies for multiple access point (AP) coordination and multiple input multiple output (MIMO) supporting an increased bandwidth, efficient utilization of multiple bands and increased spatial streams are being studied, and, in particular, various technologies for supporting low latency or real-time traffic are being studied.
The technical object of the present disclosure is to provide a method and apparatus for transmitting and receiving an NDP feedback report response in response, when transmitting an NDP feedback report poll (NFRP) trigger frame in order to determine the buffer status and data transmission for multiple stations (STAs).
In addition, the technical object of the present disclosure is to provide a method and apparatus for transmitting and receiving an NDP feedback report response considering that one or more subchannels are punctured within a physical layer protocol data unit (PPDU) bandwidth.
The technical objects to be achieved by the present disclosure are not limited to the above-described technical objects, and other technical objects which are not described herein will be clearly understood by those skilled in the pertinent art from the following description.
A method for transmitting a null data packet (NDP) feedback report response by a station (STA) in a wireless local area network (WLAN) system according to an aspect of the present disclosure may comprise: receiving an NDP feedback report poll (NFRP) trigger frame requesting an NDP feedback report response from an access point (AP); and transmitting a physical layer protocol data unit (PPDU) carrying the NDP feedback report response to the AP, in response to the NFRP trigger frame. The PPDU may be transmitted in a frequency resource corresponding to a tone set index assigned to the STA, and based on one or more subchannels in the bandwidth of the PPDU being punctured, the tone set index assigned to the STA may be determined so that the frequency resources in the one or more punctured subchannels are not included.
A method for receiving a null data packet (NDP) feedback report response by an access point (AP) in a wireless LAN system according to another aspect of the present disclosure may comprise: transmitting an NDP feedback report poll (NFRP) trigger frame requesting an NDP feedback report response to a station (STA); and receiving a physical layer protocol data unit (PPDU) carrying the NDP feedback report response from the STA, in response to the NFRP trigger frame. The PPDU may be transmitted in a frequency resource corresponding to a tone set index assigned to the STA, and based on one or more subchannels in the bandwidth of the PPDU being punctured, the tone set index assigned to the STA may be determined so that the frequency resources in the one or more punctured subchannels are not included.
According to an embodiment of the present disclosure, uplink multi-user transmission may be supported by determining the buffer status and whether or not data is transmitted for multiple STAs.
In addition, according to an embodiment of the present disclosure, uplink multi-user transmission may be supported by transmitting and receiving an NDP feedback report response despite one or more subchannels being punctured within a physical layer protocol data unit (PPDU) bandwidth.
Effects achievable by the present disclosure are not limited to the above-described effects, and other effects which are not described herein may be clearly understood by those skilled in the pertinent art from the following description.
The accompanying drawings, which are included as part of the detailed description to aid understanding of the present disclosure, provide embodiments of the present disclosure and together with the detailed description describe technical features of the present disclosure.
Hereinafter, embodiments according to the present disclosure will be described in detail by referring to accompanying drawings. Detailed description to be disclosed with accompanying drawings is to describe exemplary embodiments of the present disclosure and is not to represent the only embodiment that the present disclosure may be implemented. The following detailed description includes specific details to provide complete understanding of the present disclosure. However, those skilled in the pertinent art knows that the present disclosure may be implemented without such specific details.
In some cases, known structures and devices may be omitted or may be shown in a form of a block diagram based on a core function of each structure and device in order to prevent a concept of the present disclosure from being ambiguous.
In the present disclosure, when an element is referred to as being “connected”, “combined” or “linked” to another element, it may include an indirect connection relation that yet another element presents therebetween as well as a direct connection relation. In addition, in the present disclosure, a term, “include” or “have”, specifies the presence of a mentioned feature, step, operation, component and/or element, but it does not exclude the presence or addition of one or more other features, stages, operations, components, elements and/or their groups.
In the present disclosure, a term such as “first”, “second”, etc. is used only to distinguish one element from other element and is not used to limit elements, and unless otherwise specified, it does not limit an order or importance, etc. between elements. Accordingly, within a scope of the present disclosure, a first element in an embodiment may be referred to as a second element in another embodiment and likewise, a second element in an embodiment may be referred to as a first element in another embodiment.
A term used in the present disclosure is to describe a specific embodiment, and is not to limit a claim. As used in a described and attached claim of an embodiment, a singular form is intended to include a plural form, unless the context clearly indicates otherwise. A term used in the present disclosure, “and/or”, may refer to one of related enumerated items or it means that it refers to and includes any and all possible combinations of two or more of them. In addition, “/” between words in the present disclosure has the same meaning as “and/or”, unless otherwise described.
Examples of the present disclosure may be applied to various wireless communication systems. For example, examples of the present disclosure may be applied to a wireless LAN system. For example, examples of the present disclosure may be applied to an IEEE 802.11a/g/n/ac/ax standards-based wireless LAN. Furthermore, examples of the present disclosure may be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure may be applied to an IEEE 802.11be Release-2 standard-based wireless LAN corresponding to an additional enhancement technology of the IEEE 802.11be Release-1 standard. Additionally, examples of the present disclosure may be applied to a next-generation standards-based wireless LAN after IEEE 802.11be. Further, examples of this disclosure may be applied to a cellular wireless communication system. For example, it may be applied to a cellular wireless communication system based on Long Term Evolution (LTE)-based technology and 5G New Radio (NR)-based technology of the 3rd Generation Partnership Project (3GPP) standard.
Hereinafter, technical features to which examples of the present disclosure may be applied will be described.
The first device 100 and the second device 200 illustrated in
The devices 100 and 200 illustrated in
Referring to
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.) technologies other than wireless LAN technology. In addition, the device of the present disclosure may be implemented in various devices such as a mobile phone, a vehicle, a personal computer, augmented reality (AR) equipment, and virtual reality (VR) equipment, etc. In addition, the STA of the present specification may support various communication services such as a voice call, a video call, data communication, autonomous-driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet-of-Things), etc.
A first device 100 may include one or more processors 102 and one or more memories 104 and may additionally include one or more transceivers 106 and/or one or more antennas 108. A processor 102 may control a memory 104 and/or a transceiver 106 and may be configured to implement description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. For example, a processor 102 may transmit a wireless signal including first information/signal through a transceiver 106 after generating first information/signal by processing information in a memory 104. In addition, a processor 102 may receive a wireless signal including second information/signal through a transceiver 106 and then store information obtained by signal processing of second information/signal in a memory 104. A memory 104 may be connected to a processor 102 and may store a variety of information related to an operation of a processor 102. For example, a memory 104 may store a software code including instructions for performing all or part of processes controlled by a processor 102 or for performing description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. Here, a processor 102 and a memory 104 may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). A transceiver 106 may be connected to a processor 102 and may transmit and/or receive a wireless signal through one or more antennas 108. A transceiver 106 may include a transmitter and/or a receiver. A transceiver 106 may be used together with a RF (Radio Frequency) unit. In the present disclosure, a device may mean a communication modem/circuit/chip.
A second device 200 may include one or more processors 202 and one or more memories 204 and may additionally include one or more transceivers 206 and/or one or more antennas 208. A processor 202 may control a memory 204 and/or a transceiver 206 and may be configured to implement description, functions, procedures, proposals, methods and/or operation flows charts disclosed in the present disclosure. For example, a processor 202 may generate third information/signal by processing information in a memory 204, and then transmit a wireless signal including third information/signal through a transceiver 206. In addition, a processor 202 may receive a wireless signal including fourth information/signal through a transceiver 206, and then store information obtained by signal processing of fourth information/signal in a memory 204. A memory 204 may be connected to a processor 202 and may store a variety of information related to an operation of a processor 202. For example, a memory 204 may store a software code including instructions for performing all or part of processes controlled by a processor 202 or for performing description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. Here, a processor 202 and a memory 204 may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). A transceiver 206 may be connected to a processor 202 and may transmit and/or receive a wireless signal through one or more antennas 208. A transceiver 206 may include a transmitter and/or a receiver. A transceiver 206 may be used together with a RF unit. In the present disclosure, a device may mean a communication modem/circuit/chip.
Hereinafter, a hardware element of a device 100, 200 will be described in more detail. It is not limited thereto, but 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., a functional layer such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (Protocol Data Unit) and/or one or more SDUs (Service Data Unit) according to description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. One or more processors 102, 202 may generate a message, control information, data or information according to description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. One or more processors 102, 202 may generate a signal (e.g., a baseband signal) including a PDU, a SDU, a message, control information, data or information according to functions, procedures, proposals and/or methods disclosed in the present disclosure to provide it to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 and obtain a PDU, a SDU, a message, control information, data or information according to description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure.
One or more processors 102, 202 may be referred to as a controller, a micro controller, a micro processor or a micro computer. One or more processors 102, 202 may be implemented by a hardware, a firmware, a software, or their combination. In an example, one or more ASICs (Application Specific Integrated Circuit), one or more DSPs (Digital Signal Processor), one or more DSPDs (Digital Signal Processing Device), one or more PLDs (Programmable Logic Device) or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102, 202. Description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be implemented by using a firmware or a software and a firmware or a software may be implemented to include a module, a procedure, a function, etc. A firmware or a software configured to perform description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be included in one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. Description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be implemented by using a firmware or a software in a form of a code, an instruction and/or a set of instructions. One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, a signal, a message, information, a program, a code, an indication and/or an instruction in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, a flash memory, a hard drive, a register, a cash memory, a computer readable storage medium and/or their combination. One or more memories 104, 204 may be positioned inside and/or outside one or more processors 102, 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 through a variety of technologies such as a wire or wireless connection.
One or more transceivers 106, 206 may transmit user data, control information, a wireless signal/channel, etc. mentioned in methods and/or operation flow charts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receiver user data, control information, a wireless signal/channel, etc. mentioned in description, functions, procedures, proposals, methods and/or operation flow charts, etc. disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive a wireless signal. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information or a wireless signal to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information or a wireless signal from one or more other devices. In addition, one or more transceivers 106, 206 may be connected 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, a wireless signal/channel, etc. mentioned in description, functions, procedures, proposals, methods and/or operation flow charts, etc. disclosed in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., an antenna port). One or more transceivers 106, 206 may convert a received wireless signal/channel, etc. into a baseband signal from a RF band signal to process received user data, control information, wireless signal/channel, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, a wireless signal/channel, etc. which are processed by using one or more processors 102, 202 from a baseband signal to a RF band signal. Therefor, one or more transceivers 106, 206 may include an (analogue) oscillator and/or a filter.
For example, one of the STAs 100 and 200 may perform an intended operation of an AP, and the other of the STAs 100 and 200 may perform an intended operation of a non-AP STA. For example, the transceivers 106 and 206 of
Hereinafter, downlink (DL) may mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU/packet/signal may be transmitted and received through the DL. In DL communication, a transmitter may be part of an AP STA, and a receiver may be part of a non-AP STA. Uplink (UL) may mean a link for communication from non-AP STAs to AP STAs, and a UL PPDU/packet/signal may be transmitted and received through the UL. In UL communication, a transmitter may be part of a non-AP STA, and a receiver may be part of an AP STA.
The structure of the wireless LAN system may consist of be composed of a plurality of components. A wireless LAN supporting STA mobility transparent to an upper layer may be provided by interaction of a plurality of components. A Basic Service Set (BSS) corresponds to a basic construction block of a wireless LAN.
If the DS shown in
Membership of an STA in the BSS may be dynamically changed by turning on or off the STA, entering or exiting the BSS area, and the like. To become a member of the BSS, the STA may join the BSS using a synchronization process. In order to access all services of the BSS infrastructure, the STA shall be associated with the BSS. This association may be dynamically established and may include the use of a Distribution System Service (DSS).
A direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in some cases, communication between STAs at a longer distance may be required. A distributed system (DS) may be configured to support extended coverage.
DS means a structure in which BSSs are interconnected. Specifically, as shown in
A DS may support a mobile device by providing seamless integration of a plurality of BSSs and providing logical services necessary to address an address to a destination. In addition, the DS may further include a component called a portal that serves as a bridge for connection between the wireless LAN and other networks (e.g., IEEE 802.X).
The AP enables access to the DS through the WM for the associated non-AP STAs, and means an entity that also has the functionality of an STA. Data movement between the BSS and the DS may be performed through the AP. For example, STA2 and STA3 shown in
Data transmitted from one of the STA(s) associated with an AP to a STA address of the corresponding AP may be always received on an uncontrolled port and may be processed by an IEEE 802.1X port access entity. In addition, when a controlled port is authenticated, transmission data (or frames) may be delivered to the DS.
In addition to the structure of the DS described above, an extended service set (ESS) may be configured to provide wide coverage.
An ESS means a network in which a network having an arbitrary size and complexity is composed of DSs and BSSs. The ESS may correspond to a set of BSSs connected to one DS. However, the ESS does not include the DS. An ESS network is characterized by being seen as an IBSS in the Logical Link Control (LLC) layer. STAs included in the ESS may communicate with each other, and mobile STAs may move from one BSS to another BSS (within the same ESS) transparently to the LLC. APs included in one ESS may have the same service set identification (SSID). The SSID is distinguished from the BSSID, which is an identifier of the BSS.
The wireless LAN system does not assume anything about the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. In addition, BSSs may not be physically connected, and logically there is no limit on the distance between BSSs. In addition, the BSSs may be physically located in the same location, which may be used to provide redundancy. In addition, one (or more than one) IBSS or ESS networks may physically exist in the same space as one (or more than one) ESS network. When an ad-hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, this may correspond to the form of an ESS network in the like.
In order for an STA to set up a link with respect to a network and transmit/receive data, it first discovers a network, performs authentication, establishes an association, and need to perform the authentication process for security. The link setup process may also be referred to as a session initiation process or a session setup process. In addition, the processes of discovery, authentication, association, and security setting of the link setup process may be collectively referred to as an association process.
In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access the network, it needs to find a network in which it can participate. The STA shall identify a compatible network before participating in a wireless network, and the process of identifying a network existing in a specific area is called scanning.
Scanning schemes include active scanning and passive scanning.
Although not shown in
After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as a first authentication process in order to be clearly distinguished from the security setup operation of step S340 to be described later.
The authentication process includes a process in which the STA transmits an authentication request frame to the AP, and in response to this, the AP transmits an authentication response frame to the STA. An authentication frame used for authentication request/response corresponds to a management frame.
The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a Finite Cyclic Group, etc. This corresponds to some examples of information that may be included in the authentication request/response frame, and may be replaced with other information or additional information may be further included.
The STA may transmit an authentication request frame to the AP. The AP may determine whether to allow authentication of the corresponding STA based on information included in the received authentication request frame. The AP may provide the result of the authentication process to the STA through 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 related to various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request (TIM broadcast request), interworking service capability, etc. For example, the association response frame may include information related to various capabilities, status code, association ID (AID), supported rates, enhanced distributed channel access (EDCA) parameter set, received channel power indicator (RCPI), received signal to noise indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QOS) map, etc. This corresponds to some examples of information that may be included in the association request/response frame, and may be replaced with other information or additional information may be further included.
After the STA is successfully associated with the network, a security setup process may be performed in step S340. The security setup process of step S340 may be referred to as an authentication process through Robust Security Network Association (RSNA) request/response, and the authentication process of step S320 is referred to as a first authentication process, and the security setup process of step S340 may also simply be referred to as an authentication process.
The security setup process of step S340 may include, for example, a process of setting up a private key through 4-way handshaking through an Extensible Authentication Protocol over LAN (EAPOL) frame. In addition, the security setup process may be performed according to a security scheme not defined in the IEEE 802.11 standard.
In the wireless LAN system, a basic access mechanism of medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA/CA) mechanism. The CSMA/CA mechanism is also called Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and basically adopts a “listen before talk” access mechanism. According to this type of access mechanism, the AP and/or STA may perform Clear Channel Assessment (CCA) sensing a radio channel or medium during a predetermined time interval (e.g., DCF Inter-Frame Space (DIFS)), prior to starting transmission. As a result of the sensing, if it is determined that the medium is in an idle state, frame transmission is started through the corresponding medium. On the other hand, if it is detected that the medium is occupied or busy, the corresponding AP and/or STA does not start its own transmission and may set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying the random backoff period, since it is expected that several STAs attempt frame transmission after waiting for different periods of time, collision may be minimized.
In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). HCF is based on the DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method and refers to a method in which all receiving APs and/or STAs periodically poll to receive data frames. In addition, HCF has Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to provide data frames to multiple users, and HCCA uses a non-contention-based channel access method using a polling mechanism. In addition, the HCF includes a medium access mechanism for improving QoS (Quality of Service) of the wireless LAN, and may transmit QoS data in both a Contention Period (CP) and a Contention Free Period (CFP).
Referring to
When the random backoff process starts, the STA continuously monitors the medium while counting down the backoff slots according to the determined backoff count value. When the medium is monitored for occupancy, it stops counting down and waits, and resumes the rest of the countdown when the medium becomes idle.
In the example of
As in the example of
A Quality of Service (QOS) STA may perform the backoff that is performed after an arbitration IFS (AIFS) for an access category (AC) to which the frame belongs, that is, AIFS[i] (where i is a value determined by AC), and then may transmit the frame. Here, the frame in which AIFS[i] can be used may be a data frame, a management frame, or a control frame other than a response frame.
As described above, the CSMA/CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which a STA directly senses a medium. Virtual carrier sensing is intended to compensate for problems that may occur in medium access, such as a hidden node problem. For virtual carrier sensing, the MAC of the STA may use a Network Allocation Vector (NAV). The NAV is a value indicating, to other STAs, the remaining time until the medium is available for use by an STA currently using or having the right to use the medium. Therefore, the value set as NAV corresponds to a period in which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the corresponding period. For example, the NAV may be configured based on the value of the “duration” field of the MAC header of the frame.
In the example of
In order to reduce the possibility of collision of transmissions of multiple STAs in CSMA/CA based frame transmission operation, a mechanism using RTS/CTS frames may be applied. In the example of
Specifically, the STA1 may determine whether a channel is being used through carrier sensing. In terms of physical carrier sensing, the STA1 may determine a channel occupation idle state based on an energy level or signal correlation detected in a channel. In addition, in terms of virtual carrier sensing, the STA1 may determine a channel occupancy state using a network allocation vector (NAV) timer.
The STA1 may transmit an RTS frame to the STA2 after performing a backoff when the channel is in an idle state during DIFS. When the STA2 receives the RTS frame, the STA2 may transmit a CTS frame as a response to the RTS frame to the STA1 after SIFS.
If the STA3 cannot overhear the CTS frame from the STA2 but can overhear the RTS frame from the STA1, the STA3 may set a NAV timer for a frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter, using the duration information included in the RTS frame. Alternatively, if the STA3 can overhear a CTS frame from the STA2 although the STA3 cannot overhear an RTS frame from the STA1, the STA3 may set a NAV timer for a frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter, using the duration information included in the CTS frame. That is, if the STA3 can overhear one or more of the RTS or CTS frames from one or more of the STA1 or the STA2, the STA3 may set the NAV accordingly. When the STA3 receives a new frame before the NAV timer expires, the STA3 may update the NAV timer using duration information included in the new frame. The STA3 does not attempt channel access until the NAV timer expires.
When the STA1 receives the CTS frame from the the STA2, the STA1 may transmit the data frame to the STA2 after SIFS from the time point when the reception of the CTS frame is completed. When the STA2 successfully receives the data frame, the STA2 may transmit an ACK frame as a response to the data frame to the STA1 after SIFS. The STA3 may determine whether the channel is being used through carrier sensing when the NAV timer expires. When the STA3 determines that the channel is not used by other terminals during DIFS after expiration of the NAV timer, the STA3 may attempt channel access after a contention window (CW) according to a random backoff has passed.
By means of an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer, the PHY layer may prepare a MAC PDU (MPDU) to be transmitted. For example, when a command requesting transmission start of the PHY layer is received from the MAC layer, the PHY layer switches to the transmission mode and configures information (e.g., data) provided from the MAC layer in the form of a frame and transmits it. In addition, when the PHY layer detects a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command notifying the start of reception of the PHY layer to the MAC layer.
In this way, information transmission/reception in a wireless LAN system is performed in the form of a frame, and for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.
A basic PPDU frame 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-High Throughput (HT)) PPDU frame format may consist of only L-STF (Legacy-STF), L-LTF (Legacy-LTF), SIG field, and data field. In addition, depending on the type of PPDU frame format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), an additional (or different type) STF, LTF, and SIG fields may be included between the SIG field and the data field (this will be described later with reference to
The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, and the like, and the LTF is a signal for channel estimation and frequency error estimation. The STF and LTF may be referred to as signals for synchronization and channel estimation of the OFDM physical layer.
The SIG field may include a RATE field and a LENGTH field. The RATE field may include information on modulation and coding rates of data. The LENGTH field may include information on the length of data. Additionally, the SIG field may include a parity bit, a SIG TAIL bit, and the like.
The data field may include a SERVICE field, a physical layer service data unit (PSDU), and a PPDU TAIL bit, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer, and may include data generated/used in the upper layer. The PPDU TAIL bit may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of a data field in a predetermined unit.
A MAC PDU is 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). The MAC frame may consist of MAC PDUs and be transmitted/received through the PSDU of the data part of the PPDU frame format.
The MAC header includes a Frame Control field, a Duration/ID field, an Address field, and the like. The frame control field may include control information required for frame transmission/reception. The duration/ID field may be set to a time for transmitting a corresponding frame or the like. For details of the Sequence Control, QoS Control, and HT Control subfields of the MAC header, refer to the IEEE 802.11 standard document.
A null-data packet (NDP) frame format means a frame format that does not include a data packet. That is, the NDP frame refers to a frame format that includes a physical layer convergence procedure (PLCP) header part (i.e., STF, LTF, and SIG fields) in a general PPDU frame format and does not include the remaining parts (i.e., data field). A NDP frame may also be referred to as a short frame format.
In standards such as IEEE 802.11a/g/n/ac/ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a/g) includes L-LTF, L-STF, L-SIG and Data fields. The basic PPDU format may also be referred to as a non-HT PPDU format.
The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields to the basic PPDU format. The HT PPDU format shown in
An example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields to the basic PPDU format.
An example of the HE PPDU format (IEEE 802.11ax) additionally includes Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), Packet Extension (PE) field to the basic PPDU format. Some fields may be excluded or their length may vary according to detailed examples of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). 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 8 us. The Extended Range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16 us.
Referring to
As shown in
As shown at the top of
The RU allocation of
In the example of
Just as RUs of various sizes are used in the example of
In addition, as shown, when used for a single user, a 484-RU may be used.
Just as RUs of various sizes are used in the example of
In addition, as shown, when used for a single user, 996-RU may be used, and in this case, 5 DC tones are inserted in common with HE PPDU and EHT PPDU.
EHT PPDUs over 160 MHz may be configured with a plurality of 80 MHz subblocks in
Here, the MRU corresponds to a group of subcarriers (or tones) composed of a plurality of RUs, and the plurality of RUs constituting the MRU may be RUs having the same size or RUs having different sizes. For example, a single MRU may be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2X996+484-tone, 3X996-tone, or 3X996+484-tone. Here, the plurality of RUs constituting one MRU may correspond to small size (e.g., 26, 52, or 106) RUs or large size (e.g., 242, 484, or 996) RUs. That is, one MRU including a small size RU and a large size RU may not be configured/defined. In addition, a plurality of RUs constituting one MRU may or may not be consecutive in the frequency domain.
When an 80 MHz subblock includes RUs smaller than 996 tones, or parts of the 80 MHz subblock are punctured, the 80 MHz subblock may use RU allocation other than the 996-tone RU.
The RU of the present disclosure may be used for uplink (UL) and/or downlink (DL) communication. For example, when trigger-based UL-MU communication is performed, the STA transmitting the trigger (e.g., AP) may allocate a first RU (e.g., 26/52/106/242-RU, etc.) to a first STA and allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA, through trigger information (e.g., trigger frame or triggered response scheduling (TRS)). Thereafter, the first STA may transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA may transmit a second TB PPDU based on the second RU. The first/second TB PPDUs may be transmitted to the AP in the same time period.
For example, when a DL MU PPDU is configured, the STA transmitting the DL MU PPDU (e.g., AP) may allocate a first RU (e.g., 26/52/106/242-RU, etc.) to a first STA and allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA. That is, the transmitting STA (e.g., AP) may transmit HE-STF, HE-LTF, and Data field for the first STA through the first RU and transmit HE-STF, HE-LTF, and Data field for the second STA through the second RU, in one MU PPDU,
Information on the allocation of RUs may be signaled through HE-SIG-B in the HE PPDU format.
As shown, the HE-SIG-B field may include a common field and a user-specific field. If HE-SIG-B compression is applied (e.g., full-bandwidth MU-MIMO transmission), the common field may not be included in HE-SIG-B, and the HE-SIG-B content channel may include only a user-specific field. If HE-SIG-B compression is not applied, the common field may be included in HE-SIG-B.
The common field may include information on RU allocation (e.g., RU assignment, RUs allocated for MU-MIMO, the number of MU-MIMO users (STAs), etc.)
The common field may include N*8 RU allocation subfields. Here, N is the number of subfields, N=1 in the case of 20 or 40 MHz MU PPDU, N=2 in the case of 80 MHz MU PPDU, N=4 in the case of 160 MHz or 80+80 MHz MU PPDU, etc. One 8-bit RU allocation subfield may indicate the size (26, 52, 106, etc.) and frequency location (or RU index) of RUs included in the 20 MHz band.
For example, if a value of the 8-bit RU allocation subfield is 00000000, it may indicate that nine 26-RUs are sequentially allocated in order from the leftmost to the rightmost in the example of
As an additional example, if the value of the 8-bit RU allocation subfield is 01000y2y1y0, it may indicate that one 106-RU and five 26-RUs are sequentially allocated from the leftmost to the rightmost in the example of
Basically, one user/STA may be allocated to each of a plurality of RUs, and different users/STAs may be allocated to different RUs. For RUs larger than a predetermined size (e.g., 106, 242, 484, 996-tones, . . . ), a plurality of users/STAs may be allocated to one RU, and MU-MIMO scheme may be applied for the plurality of users/STAs.
The set of user-specific fields includes information on how all users (STAs) of the corresponding PPDU decode their payloads. User-specific fields may contain zero or more user block fields. The non-final user block field includes two user fields (i.e., information to be used for decoding in two STAs). The final user block field contains one or two user fields. The number of user fields may be indicated by the RU allocation subfield of HE-SIG-B, the number of symbols of HE-SIG-B, or the MU-MIMO user field of HE-SIG-A. A User-specific field may be encoded separately from or independently of a common field.
In the example of
The user field may be constructed based on two formats. The user field for a MU-MIMO allocation may be constructed with a first format, and the user field for non-MU-MIMO allocation may be constructed with a second format. Referring to the example of
The user field of the first format (i.e., format for MU-MIMO allocation) may be constructed as follows. For example, out of all 21 bits of one user field, B0-B10 includes the user's identification information (e.g., STA-ID, AID, partial AID, etc.), B11-14 includes spatial configuration information such as the number of spatial streams for the corresponding user, B15-B18 includes Modulation and Coding Scheme (MCS) information applied to the Data field of the corresponding PPDU, B19 is defined as a reserved field, and B20 may include information on a coding type (e.g., binary convolutional coding (BCC) or low-density parity check (LDPC)) applied to the Data field of the corresponding PPDU.
The user field of the second format (i.e., the format for non-MU-MIMO allocation) may be constructed as follows. For example, out of all 21 bits of one user field, B0-B10 includes the user's identification information (e.g., STA-ID, AID, partial AID, etc.), B11-13 includes information on the number of spatial streams (NSTS) applied to the corresponding RU, B14 includes information indicating whether beamforming is performed (or whether a beamforming steering matrix is applied), B15-B18 includes Modulation and Coding Scheme (MCS) information applied to the Data field of the corresponding PPDU, B19 includes information indicating whether DCM (dual carrier modulation) is applied, and B20 may include information on a coding type (e.g., BCC or LDPC) applied to the Data field of the corresponding PPDU.
MCS, MCS information, MCS index, MCS field, and the like used in the present disclosure may be indicated by a specific index value. For example, MCS information may be indicated as index 0 to index 11. MCS information includes information on constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.), and coding rate (e.g., 1/2, 2/3, 3/4, 5/6, etc.). Information on a channel coding type (e.g., BCC or LDPC) may be excluded from the MCS information.
The PPDU of
The EHT MU PPDU of
In the EHT TB PPDU of
In the example of the EHT PPDU format of
A Subcarrier frequency spacing of L-STF, L-LTF, L-SIG, RL-SIG, Universal SIGNAL (U-SIG), EHT-SIG field (these are referred to as pre-EHT modulated fields) may be set to 312.5 kHz. A subcarrier frequency spacing of the EHT-STF, EHT-LTF, Data, and PE field (these are referred to as EHT modulated fields) may be set to 78.125 kHz. That is, the tone/subcarrier index of L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG field may be indicated in units of 312.5 kHz, and the tone/subcarrier index of EHT-STF, EHT-LTF, Data, and PE field may be indicated in units of 78.125 kHz.
The L-LTF and L-STF of
The L-SIG field of
For example, the transmitting STA may apply BCC encoding based on a coding rate of 1/2 to 24-bit information of the L-SIG field. Thereafter, the transmitting STA may obtain 48-bit BCC coded bits. BPSK modulation may be applied to 48-bit coded bits to generate 48 BPSK symbols. The transmitting STA may map 48 BPSK symbols to any location except for a pilot subcarrier (e.g., {subcarrier index −21, −7, +7, +21}) and a DC subcarrier (e.g., {subcarrier index 0}). As a result, 48 BPSK symbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to −1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may additionally map the signals of {−1, −1, −1, 1} to the subcarrier index {−28, −27, +27, +28}. The above signal may be used for channel estimation in the frequency domain corresponding to {−28, −27, +27, +28}.
The transmitting STA may construct RL-SIG which is constructed identically to L-SIG. For RL-SIG, BPSK modulation is applied. The receiving STA may recognize that the received PPDU is a HE PPDU or an EHT PPDU based on the existence of the RL-SIG.
After the RL-SIG of
The U-SIG may include N-bit information and may include information for identifying the type of EHT PPDU. For example, U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the U-SIG may have a total 8 us duration. Each symbol of the U-SIG may be used to transmit 26 bit information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.
Through the U-SIG (or U-SIG field), for example, A bit information (e.g., 52 un-coded bits) may be transmitted, the first symbol of the U-SIG (e.g., U-SIG-1) may transmit the first X bit information (e.g., 26 un-coded bits) of the total A bit information, and the second symbol of the U-SIG (e.g., U-SIG-2) may transmit the remaining Y-bit information (e.g., 26 un-coded bits) of the total A-bit information. For example, the transmitting STA may obtain 26 un-coded bits included in each U-SIG symbol. The transmitting STA may generate 52-coded bits by performing convolutional encoding (e.g., BCC encoding) based on a rate of R=1/2, and perform interleaving on the 52-coded bits. The transmitting STA may generate 52 BPSK symbols allocated to each U-SIG symbol by performing BPSK modulation on the interleaved 52-coded bits. One U-SIG symbol may be transmitted based on 56 tones (subcarriers) from subcarrier index −28 to subcarrier index +28, except for DC index 0. The 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) excluding pilot tones −21, −7, +7, and +21 tones.
For example, the A bit information (e.g., 52 un-coded bits) transmitted by the U-SIG includes a CRC field (e.g., a 4-bit field) and a tail field (e.g., 6 bit-length field). The CRC field and the tail field may be transmitted through the second symbol of the U-SIG. The CRC field may be constructed based on 26 bits allocated to the first symbol of U-SIG and 16 bits remaining except for the CRC/tail field in the second symbol, and may be constructed based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolution decoder, and for example, the tail field may be set to 0.
A bit information (e.g., 52 un-coded bits) transmitted by the U-SIG (or U-SIG field) may be devided into version-independent bits and version-dependent bits. For example, a size of the version-independent bits may be fixed or variable. For example, the version-independent bits may be allocated only to the first symbol of U-SIG, or the version-independent bits may be allocated to both the first symbol and the second symbol of U-SIG. For example, the version-independent bits and the version-dependent bits may be referred as various names such as a first control bit and a second control bit, etc.
For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier). For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted/received PPDU. For example, the first value of the 3-bit PHY version identifier may indicate that the transmission/reception PPDU is an EHT PPDU. In other words, when transmitting the EHT PPDU, the transmitting STA may set the 3-bit PHY version identifier to a first value. In other words, the receiving STA may determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.
For example, the version-independent bits of U-SIG may include a 1-bit UL/DL flag field. A first value of the 1-bit UL/DL flag field is related to UL communication, and a second value of the UL/DL flag field is related to DL communication.
For example, the version-independent bits of the U-SIG may include information on the length of a transmission opportunity (TXOP) and information on a BSS color ID.
For example, if the EHT PPDU is classified into various types (e.g., EHT PPDU related to SU mode, EHT PPDU related to MU mode, EHT PPDU related to TB mode, EHT PPDU related to Extended Range transmission, etc.), information on the type of EHT PPDU may be included in the version-dependent bits of the U-SIG.
For example, the U-SIG may include information on 1) a bandwidth field containing information on a bandwidth, 2) a field containing information on a MCS scheme applied to EHT-SIG, 3) an indication field containing information related to whether the DCM technique is applied to the EHT-SIG, 4) a field containing information on the number of symbols used for EHT-SIG, 5) a field containing information on whether EHT-SIG is constructed over all bands, 6) a field containing information on the type of EHT-LTF/STF, and 7) a field indicating the length of EHT-LTF and CP length.
Preamble puncturing may be applied to the PPDU of
For example, for an EHT MU PPDU, information on preamble puncturing may be included in the U-SIG and/or the EHT-SIG. For example, the first field of the U-SIG may include information on the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information on preamble puncturing applied to the PPDU.
For example, the U-SIG and the EHT-SIG may include information on preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHZ, the U-SIG may be individually constructed in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHz band and a second U-SIG for a second 80 MHz band. In this case, the first field of the first U-SIG includes information on the 160 MHz bandwidth, and the second field of the first U-SIG includes information on preamble puncturing applied to the first 80 MHz band (i.e., information on a preamble puncturing pattern). In addition, the first field of the second U-SIG includes information on a 160 MHz bandwidth, and the second field of the second U-SIG includes information on preamble puncturing applied to a second 80 MHz band (i.e., information on a preamble puncturing pattern). The EHT-SIG following the first U-SIG may include information on preamble puncturing applied to the second 80 MHz band (i.e., information on a preamble puncturing pattern), and the EHT-SIG following the second U-SIG may include information on preamble puncturing applied to the first 80 MHz band (i.e., information on a preamble puncturing pattern).
Additionally or alternatively, the U-SIG and the EHT-SIG may include information on preamble puncturing based on the following method. The U-SIG may include information on preamble puncturing for all bands (i.e., information on a preamble puncturing pattern). That is, EHT-SIG does not include information on preamble puncturing, and only U-SIG may include information on preamble puncturing (ie, information on a preamble puncturing pattern).
U-SIG may be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG may be duplicated. That is, the same 4 U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding 80 MHz bandwidth may include different U-SIGs.
The EHT-SIG of
The EHT-SIG may include technical features of HE-SIG-B described through FIGS. 11 and 12. For example, EHT-SIG, like the example of
As in the example of
In the same way as in the example of
As in the example of
A mode in which a common field of EHT-SIG is omitted may be supported. The mode in which the common field of the EHT-SIG is omitted may be referred as a compressed mode. When the compressed mode is used, a plurality of users (i.e., a plurality of receiving STAs) of the EHT PPDU may decode the PPDU (e.g., the data field of the PPDU) based on non-OFDMA. That is, a plurality of users of the EHT PPDU may decode a PPDU (e.g., a data field of the PPDU) received through the same frequency band. When a non-compressed mode is used, multiple users of the EHT PPDU may decode the PPDU (e.g., the data field of the PPDU) based on OFDMA. That is, a plurality of users of the EHT PPDU may receive the PPDU (e.g., the data field of the PPDU) through different frequency bands.
EHT-SIG may be constructed based on various MCS scheme. As described above, information related to the MCS scheme applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be constructed based on the DCM scheme. The DCM scheme may reuse the same signal on two subcarriers to provide an effect similar to frequency diversity, reduce interference, and improve coverage. For example, modulation symbols to which the same modulation scheme is applied may be repeatedly mapped on available tones/subcarriers. For example, modulation symbols (e.g., BPSK modulation symbols) to which a specific modulation scheme is applied may be mapped to first contiguous half tones (e.g., 1st to 26th tones) among the N data tones (e.g., 52 data tones) allocated for EHT-SIG, and modulation symbols (e.g., BPSK modulation symbols) to which the same specific modulation scheme is applied may be mapped to the remaining contiguous half tones (e.g., 27th to 52nd tones). That is, a modulation symbol mapped to the 1st tone and a modulation symbol mapped to the 27th tone are the same. As described above, information related to whether the DCM scheme is applied to the EHT-SIG (e.g., a 1-bit field) may be included in the U-SIG. The EHT-STF of
Information on the type of STF and/or LTF (including information on a guard interval (GI) applied to LTF) may be included in the U-SIG field and/or the EHT-SIG field of
The PPDU (i.e., EHT PPDU) of
For example, a EHT PPDU transmitted on a 20 MHz band, that is, a 20 MHz EHT PPDU may be constructed based on the RU of
The EHT PPDU transmitted on the 80 MHz band, that is, the 80 MHz EHT PPDU may be constructed based on the RU of
The tone-plan for 160/240/320 MHz may be configured in the form of repeating the pattern of
The PPDU of
The receiving STA may determine the type of the received PPDU as the EHT PPDU based on the following. For example, when 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) RL-SIG in which the L-SIG of the received PPDU is repeated is detected, and 3) the result of applying the modulo 3 calculation to the value of the Length field of the L-SIG of the received PPDU (i.e., the remainder after dividing by 3) is detected as 0, the received PPDU may be determined as a EHT PPDU. When the received PPDU is determined to be an EHT PPDU, the receiving STA may determine the type of the EHT PPDU based on bit information included in symbols subsequent to the RL-SIG of
For example, the receiving STA may determine the type of the received PPDU as the HE PPDU based on the following. For example, when 1) the first symbol after the L-LTF signal is BPSK, 2) RL-SIG in which L-SIG is repeated is detected, and 3) the result of applying modulo 3 to the length value of L-SIG is detected as 1 or 2, the received PPDU may be determined as a HE PPDU.
For example, the receiving STA may determine the type of the received PPDU as non-HT, HT, and VHT PPDU based on the following. For example, when 1) the first symbol after the L-LTF signal is BPSK and 2) RL-SIG in which L-SIG is repeated is not detected, the received PPDU may be determined as non-HT, HT, and VHT PPDU.
In addition, when the receiving STA detects an RL-SIG in which the L-SIG is repeated in the received PPDU, it may be determined that the received PPDU is a HE PPDU or an EHT PPDU. In this case, if the rate (6 Mbps) check fails, the received PPDU may be determined as a non-HT, HT, or VHT PPDU. If the rate (6 Mbps) check and parity check pass, when the result of applying modulo 3 to the Length value of L-SIG is detected as 0, the received PPDU may be determined as an EHT PPDU, and when the result of Length mod 3 is not 0, it may be determined as a HE PPDU.
The PPDU of
Hereinafter, the U-SIG included in the EHT PPDU will be described in more detail.
For a 40 MHz EHT PPDU or Extended Range (ER) preamble, the U-SIG content is the same in both 20 MHz subchannels. For an 80 MHz EHT PPDU or ER preamble, the U-SIG content is the same in all non-punctured 20 MHz subchannels. For a 160/320 MHz EHT PPDU or ER preamble, the U-SIG content is the same on all non-punctured 20 MHz subchannels within each 80 MHz subblock and may be different from the U-SIG content in other 80 MHz subblocks.
The U-SIG-1 part of the U-SIG of the EHT MU PPDU may include PHY version identifier (B0-B2), BW (B3-B5), UL/DL (B6), BSS color (B7-B12), and TXOP (B13-B19), and U-SIG-2 part may include PPDU type and compression mode (B0-B1), validate (B2), punctured channel information (B3-B7), validate (B8), EHT-SIG MCS (B9-B10), number of EHT-SIG symbols (B11-B15), CRC (B16-B19), and tail (B20-B25).
Here, an example of a 5-bit punctured channel indication for a non-OFDMA case in the EHT MU PPDU is shown in Table 1 below.
In the puncturing pattern of Table 1, 1 denotes a non-punctured subchannel, and x denotes a punctured subchannel. The puncturing granularity for the 80 MHz and 160 MHz PPDU bandwidths may be 20 MHZ, and the puncturing granularity for the 320 MHz PPDU bandwidth may be 40 MHz.
Next, the U-SIG-1 part of the U-SIG of the EHT TB PPDU may include a version identifier (B0-B2), BW (B3-B5), UL/DL (B6), BSS color (B7-B12), TXOP (B13-B19), and disregard (B20-B25), and U-SIG-2 part may include PPDU type and compression mode (B0-B1), validate (B2), spatial reuse 1 (B3-B6), spatial reuse 2 (B7-B10), disregard (B11-B15), CRC (B16-B19), and tail (B20-B25).
As described above, the U-SIG field of the EHT MU PPDU includes 5-bit punctured channel information, but the EHT TB PPDU does not include punctured channel information. This is because it is assumed that the EHT TB PPDU is constructed according to resource allocation indicated by the trigger frame or TRS control information, so the STA does not need to inform the AP of the resource information of the EHT TB PPDU.
In addition, even if the trigger frame or TRS control information as described above is received, the STA may not respond with the HE TB PPDU. For example, if, in the non-AP STA, a common information field included in the trigger frame or one or more subfields of an user field addressed to the non-AP STA or selected by the non-AP STA are not recognized, supported, or have an unsatisfied value, the corresponding non-AP STA may choose not to respond to the trigger frame. Similarly, if, in the non-AP STA, a TRS control subfield included in a frame addressed to the non-AP STA is not recognized by the non-AP STA, is not supported, or has an unsatisfied value, the corresponding non-AP STA may choose not to respond to the TRS control subfield.
The NDP feedback report procedure allows an HE AP to collect feedback that is not channel sounding from multiple non-AP HE STAs.
An HE AP sends an NDP feedback report poll (NFRP) Trigger frame to solicit NDP feedback report response from many non-AP STAs that are identified by a range of scheduled AIDs in the Trigger frame. The NDP feedback report response from a non-AP STA is an HE TB feedback NDP. A non-AP STA uses the information included in the NFRP Trigger frame to know if it is scheduled and, in this case, to derive the parameters for the transmission of the response.
A non-AP STA shall set the NDP Feedback Report Support subfield in the HE Capabilities element to 1 if it supports NDP feedback report and set it 0, otherwise.
A non-AP STA shall not transmit an NDP feedback report response, unless it is explicitly enabled by an AP in one of the operation modes. The interframe space between a PPDU that contains an NFRP Trigger frame and the NDP feedback report poll response is SIFS. A non-AP STA shall commence the transmission of an NDP feedback report response at the SIFS time boundary after the end of a received PPDU if all the following conditions are met.
A non-AP STA that does not satisfy all of the above conditions shall not respond to the NFRP Trigger frame.
A non-AP STA is scheduled to respond to the NFRP Trigger frame if all the following conditions are met.
The non-AP STA is associated with an AP corresponding to the basic service set identifier (BSSID) indicated in the TA field of the NFRP Trigger frame; or the non-AP STA is associated with an AP corresponding to a non-transmitted BSSID of a multiple BSSID set, and the TA field of the NFRP Trigger frame is set to the transmitted BSSID of that multiple BSSID set.
The AID of the non-AP STA is greater than or equal to the starting AID and less than the starting AID+NSTA. Herein, the Starting AID subfield in the eliciting Trigger frame and NSTA as the total number of non-AP STAs that are scheduled to respond to the NFRP Trigger frame. NSTA is calculated by the following equation, using UL BW subfield and Number Of Spatially Multiplexed Users subfield from the eliciting Trigger frame: NSTA=18×2BW×(value of the Number Of Spatially Multiplexed Users subfield+1)
A non-AP STA shall obtain NDP feedback report parameter values from the most recently received NDP Feedback Report Parameter Set element carried in a Beacon, Probe Response, or (Re) Association Response frame from its associated AP, unless the non-AP STA is associated with an AP corresponding to a nontransmitted BSSID of a multiple BSSID set. In this case, it shall follow the rules in 11.1.3.8.4 to determine the NDP feedback parameter values. If the NDP Feedback Report Parameter Set element is not received in a Management frame with a TA equal to the BSSID of the associated AP or to the transmitted BSSID of the multiple BSSID set, the non-AP STA shall use default values for the NDP Feedback Report parameters.
An NDP feedback report response is an HE TB feedback NDP.
A non-AP STA transmitting an NDP feedback report response shall set the TXVECTOR parameters as for transmitting an HE TB PPDU in response to a Trigger frame that is not an MU-RTS Trigger frame as described in 26.5.2.3 (Non-AP STA behavior for UL MU operation), except for the following parameters:
Here, Starting AID is the value of the Starting AID subfield in the User Info field in the NFRP Trigger frame. Additionally, BW is the value of the UL BW subfield in the Common Info field in the NFRP Trigger frame. The UL BW subfield indicates the bandwidth within the HE-SIG-A field of the HE TB PPDU and can be encoded as shown in Table 2 below.
The TXPWR_LEVEL_INDEX parameter shall be set to the value based on the Transmit Power Control for an HE TB PPDU and based on the value of the AP Tx Power subfield and the UL Target Receive Power subfield in the User Info field of the eliciting Trigger frame.
An AP shall set the NDP Feedback Report Support subfield in the HE Capabilities element to 1 if it supports NDP feedback report and set it 0 otherwise.
An AP may include the NDP Feedback Report Parameter Set element in Beacon frames, Probe Response frames, and (Re) Association Response frames in order to modify parameters for NDP Feedback Report operation. The procedure of NDP Feedback report allows operation even if the NDP Feedback Report Parameter Set element is not sent by the AP.
The NFRP Trigger frame shall be transmitted in a non-HT PPDU or HT PPDU, or as a tagged MPDU in a VHT, HE ER SU PPDU, or HE SU PPDU.
An AP that transmits an NFRP Trigger frame shall set the TA field of the frame to the MAC address of the AP, unless dot11MultiBSSIDImplemented is true and the Trigger frame is directed to STAs from at least two different BSSs of a multiple BSSID set. In this case, the AP shall set the TA field of the frame to the transmitted BSSID.
Following the transmission from an AP of an NFRP Trigger frame, multiple STAs may simultaneously send NDP feedback report responses to the AP. Based on the RXVECTOR parameter NDP_REPORT, which provides the detected status array for the resources of each spatial stream and tone set assigned by the Trigger frame, the AP may derive the list of AIDs from the resources to which an NDP feedback report response was sent and their responses.
The AP shall not send any acknowledgment in response to the reception of NDP feedback report responses.
The trigger frame may allocate resources for transmission of one or more TB PPDUs and request transmission of TB PPDUs. The trigger frame may also include other information required by the STA, which transmits the TB PPDU in response. The trigger frame may include common info and user info list fields in the frame body.
The Common info field may include information commonly applied to the transmission of one or more TB PPDUs requested by a trigger frame, such as trigger type, UL length, whether a subsequent trigger frame exists (e.g., More TF), whether channel sensing (CS) is required, UL BW (bandwidth), etc.
In the case of an NDP feedback report poll (NFRP) Trigger frame, the UL BW subfield in the Common Info field indicates the bandwidth of the NDP feedback report response. The UL STBC, LDPC Extra Symbol Segment, Pre-FEC Padding Factor, PE Diambiguity, UL Spatial Reuse, and Doppler subfields in the Common Info field are reserved. The Number Of HE LTE Symbols And Midable Periodicity subfield in the Common Info field indicates the number of HE-LTF symbols present in the NDP feedback report response and is set to 1. The GI And HE-LTF Type subfield in the Common Info field is set to 2. The Tigger Dependent Common Info subfield does not exist.
The user info list includes zero or more user information (user info) fields.
In particular,
Feedback Type subfield encoding may be defined as in Table 3 below.
The non-AP HE STA that is scheduled is identified by the AID range. The Starting AID field indicates the first AID in the AID range scheduled to respond to the NFRP Trigger frame.
If the Feedback Type subfield in the User Info field of the NFRP Trigger frame is 0, a STA that is scheduled may send an NDP feedback report response in order to signal to the AP that it is in the awake state and that it might have frames in its queues for UL MU. If the STA does not satisfy either of the conditions in Table 26-3 (FEEDBACK_STATUS description(11ax)), then the STA shall not respond to the NFRP Trigger frame.
Each STA that is scheduled is assigned a STARTING_STS_NUM and an RU_TONE_SET_INDEX to transmit a FEEDBACK_STATUS bit.
The meaning of the FEEDBACK_STATUS bit is shown in Table 4 below.
The resource request buffer threshold is equal to 2(Resource request buffer threshold exponent) octets, using the Resource Request Buffer Threshold Exponent subfield in the most recently received NDP Feedback Report Parameter Set element sent by the AP with which the STA is associated. The resource request buffer threshold is equal to 256 octets, if the STA did not receive an NDP Feedback Report Parameter Set element from the AP with which the STA is associated.
The UL Target Receive Power subfield indicates the expected receive signal power, measured at the AP's antenna connector and averaged over the antennas, for the HE portion of the HE TB PPDU transmitted on the assigned RU.
The Number Of Spatially Multiplexed Users subfield indicates the number of STAs that are multiplexed on the same set of tones in the same RU, and is encoded as the number of STAs minus 1.
The number of STAs, NSTA, that are scheduled to respond to the NFRP Trigger frame is calculated using the following Equation: NSTA=18×2BW×(MultiplexingFlag+1)
Herein, BW is the value of the UL BW subfield in the Common Info field of the NFRP Trigger frame, and MultiplexingFlag is the value of the Number Of Spatially Multiplexed Users subfield.
As described above, the NDP feedback report response that the STA sends in response to the NFRP Trigger frame is HE TB feedback NDP.
The HE TB feedback NDP is used to carry the NDP feedback report information.
The HE TB feedback NDP has the following properties:
Table 5 below illustrates HE-LTF subcarrier mapping for HE TB feedback NDP.
Referring to Table 5, Ktone_NDPu is a set of subcarrier indices for user u, and is defined according to RU_TONE_SET_INDEX and FEEDBACK_STATUS. Herein, RU_TONE_SET_INDEX indicates a set of RU tones (i.e., subcarriers of resource units) used for HE TB feedback NDP.
Considering backward compatibility, the 11be PPDU for transmitting signals to a single STA/multiple STAs may be configured as shown in
Additionally, U-SIG may be classified into a version independent field and a version dependent field, as described above.
The version independent field may include a 3-bit version identifier indicating 11be and later Wi-Fi versions, 1-bit DL/UL, BSS color, and TXOP duration, or the like. The version dependent field may include information such as PPDU format type, bandwidth, MCS, or the like.
U-SIG is jointly encoded with two symbols and configured with 52 data tones and 4 pilot tones for each 20 MHz. It is also modulated in the same way as 11ax HE-SIG-A. In other words, it is modulated at BPSK 1/2 code rate.
EHT-SIG may be configured to include version dependent fields (e.g., some of the fields included in 11ax HE-SIGA) that are not included in U-SIG. EHT-SIG is configured with multiple OFDM symbols and is modulated using various MCS (e.g., MCS0 to MCS5).
EHT-SIG is configured with a common field and a user specific field, and the common field includes RU allocation information. And the user specific field is configured with a user block field (consisting of 1 or 2 user fields) containing information on the user. EHT-SIG is configured with an EHT-SIG content channel composed of 20 mhz segments, and two content channels is configured in a PPDU of 80 mhz or higher. In addition, EHT-SIG may be configured to include different information in 80 MHz units.
Preamble puncturing information may be indicated through U-SIG and/or EHT-SIG, and puncturing information may be transmitted through U-SIG as follows.
As described above, the U-SIG-1 part of the U-SIG of the EHT MU PPDU may include PHY version identifier (B0-B2), BW (B3-B5), UL/DL (B6), and BSS color (B7-B12), and TXOP (B13-B19), and the U-SIG-2 part may include PPDU Type and Compression Mode (B0-B1), validate (B2), punctured channel information (B3-B7), validate (B8), EHT-SIG MCS (B9-B10), number of EHT-SIG symbols (B11-B15), CRC (B16-B19), and tail (B20-B25).
A description of the punctured channel information (B3-B7) in the U-SIG-2 part of the EHT MU PPDU is as follows.
Table 6 illustrates the 5-bit punctured channel indication for the non-OFDMA case in the EHT MU PPDU.
In 802.11 be, punctured BW is mandatory for efficient BW use and wide bandwidth use.
An NDP feedback report procedure that uses an NDP feedback report poll (NFRP) trigger frame is defined to determine the buffer status and transmission status of multiple terminals defined in 802.11ax. However, the response to the NFRP trigger frame only supports transmission in full bandwidth.
In other words, as described above, the NFRP Trigger frame and its response (i.e., NDP feedback report response) may be transmitted and received using various puncturing patterns (PP) for each BW. Therefore, following transmission of the NFRP Trigger frame from the AP, when multiple STAs simultaneously transmit NDP feedback report responses to the AP, when using punctured BW, an indication for the tone set (or RU tone set) that transmits the response to the NFRP to the various STAs are required. In other words, an indication of the tone set available within the punctured BW is required for the various STAs.
Here, since the tone set index included in the punctured channel may not be used when performing NFRP (i.e., performing NDP feedback report procedure) using punctured BW, it is necessary to asssign a tone set index other than this to the STA.sss
Accordingly, in the present disclosure, considering various puncturing patterns for each BW are considered in a wireless LAN system (e.g., in 802.11 be), a method to indicate a tone set for performing the NFRP procedure (i.e., NDP feedback report procedure) is proposed.
Hereinafter, in the description of the present disclosure, the previously described description may be used supplementally to apply/implement the proposed method of the present disclosure, even if no special mention is made.
In addition, in the following description of the present disclosure, tone set index may mean an index for a tone set (or RU or RU tone set) allocated to each STA, and may also be referred to as RU tone set index. In other words, each STA may send a response to the NFRP Trigger frame (i.e., NDP feedback report response) on the resource corresponding to the tone set (or RU or RU tone set) allocated to itself (or derived based on its AID, etc.).
Embodiment 1: When using punctured BW as above, information on the tone set index that transmits the response to NFRP (i.e., NDP feedback report response) may be transmitted to each STA using the user info field of the NFRP trigger frame as follows.
For example, the AP may indicate a tone set index using a reserved bit in the user info field of the NFRP trigger frame.
For example, in 802.11be, up to 320 MHz may be used as a PPDU bandwidth, here, the maximum number of supportable STAs (Num_STA) may be 18 (number of tone sets available per 20 MHz)×16 (number of 20 MHz in BW)×2 (number of multiplexed users)=576. Here, 2 users per 26 RU may be multiplexed, there are 24 data tones excluding the pilot tone among the 26 tones, and 12 tones may be allocated to each user.
The maximum available tone set index may also be the same as Num_STA, therefore, in order to indicate the number of tone sets above, reserved bits of the User Info field in the NFRP Trigger frame may be used.
Previously, in
As described above, the maximum number of STAs that may be supported within the available PPDU bandwidth of up to 320 MHz is 576, and the maximum applicable tone set index may be 576, equal to the maximum number of supportable STAs. Therefore, 10 bits may be needed to indicate a tone set index to support the maximum number of STAs. Here, the 10 bits may be configured/defined as a field for carrying information on the tone set index (e.g., tone set index information field) and may be included in the User Info field as shown in
Referring to
In addition, referring to
In
Here, the User Info field within the NFRP Trigger frame may be located immediately after the Special User Info field. The Special User Info field is a User Info field that does not carry user-specific information, but carries extended common information not provided within the Common Info field. If the Special User Info field is included in the Trigger frame, the Special User Info Field Flag subfield in the Common Info field is set to 0, otherwise it is set to 1. The Special User Info field, if present, may be located immediately after the Common Info field of the Trigger frame and carries information on sthe U-SIG field of the solicited EHT TB PPDU.
The EHT STA may recognize/identify that the User Info field format in the NFRP Trigger frame is configured as described above (e.g., see
Alternatively, an STA scheduled to transmit an NDP feedback report response may recognize/identify that the User Info field format is configured as described above (e.g., see
For example, if the B54 and B55 bits of the Common Info field of the NFRP Trigger frame are set as follows, the STA performing the NDP feedback report response transmission may recognize/identify that the User Info field format is configured as described above (e.g., see
Option 1) Set both B54 and B55 bits to 0 (in this case, as described above, the User Info field is configured to include a tone set index information subfield (e.g., see
Option 2) B54 bit is set to 1 and B55 bit is set to 0 (in this case, as described above, the User Info field is configured to include a tone set index information subfield (e.g., see
As described above, because the tone set index is indicated using the reserved bit present in the User Info field in the NFRP Trigger frame, there is an advantage that no additional signaling overhead occurs for transmitting tone set index information.
In addition, as described above, by indicating the tone set index allocated to the STA through the tone set index information subfield of the User Info field, NFRP may be performed (i.e., NDP feedback report procedure) using punctured BW.
Embodiment 2: Unlike the method of indicating information on the tone index set through a field (e.g., User Info field) in Embodiment 1, the tone set for NDP feedback report may be indicated through reordering considering the preamble puncturing of the BW as follows.
The STA performing an NDP feedback report may recognize/identify information (i.e., may receive the information) on 20 MHz channel(s) punctured in the BW, using the Disabled Subchannel Bitmap (DSB) information (field) transmitted through a beacon frame. The DSB field is a 16-bit bitmap whose lowest-numbered bit is within the BSS bandwidth and corresponds to the 20 MHz subchannel with the lowest frequency among the set of all 20 MHz subchannels within the BSS bandwidth. Each consecutive bit in the bitmap corresponds to the next higher frequency 20 MHz subchannel. In other words, starting from the first bit of the DSB field, each bit may correspond to each 20 MHz subchannel in ascending frequency order, starting from the 20 MHz subchannel with the lowest frequency within the BSS bandwidth. A bit in the bitmap is set to 1 to indicate that the corresponding 20 MHz subchannel has been punctured, and is set to 0 to indicate that the corresponding 20 MHz subchannel has not been punctured. Since the DSB (i.e., unavailable subchannel bitmap) information is used statically in the BSS, the tone set index may be configured as follows using the information.
The RU tone set index for the NFRP response (i.e., NDP feedback report response) may be reordered using DSB information, excluding the punctured 20 MHz subchannel(s). That is, the RU tone set index may not be configured for the punterued 20 MHz subchannel(s).
For example, in the case where the secondary 20 MHz (20 MHz subchannel with the second lowest frequency from the lowest) is punctured in 80 MHz, Disabled Subchannel Bitmap (16 bit) may be set to [0100 0000 0000 0000]. The four leftmost bits in [0100 0000 0000 0000] indicates the 80 MHz frequency bandwidth, and since the second bit value is 1, it is assumed that the secondary 20 MHz subchannel is punctured. Here, the tone set index may be configured as shown in Table 7 below using the DSB.
Table 7 illustrates reordering for a punctured 80 MHz channel.
The tone set index for the NFRP response (i.e., NDP feedback report response) may be reordered according to the DSB of the BSS. That is, as shown in Table 7, a tone set index may not be assigned to the punctured 20 MHz subchannel.
In other words, the tone set index may be reordered according to the BW and DSB of the PPDU (i.e., information on the punctured subchannel) using the same method as above. The RU tone set index reordered using the above method may be assigned to STAs that respond to NFRP (i.e., transmit an NDP feedback report response) using the following formula.
Here, Ω20 MHz is the number of 20 MHz (sub) channels that are not punctured within BW (i.e., bandwidth of PPDU). Additionally, Ω20 MHz may be determined through DSB transmitted through a Beacon frame or EHT operation element.
As another example, the above formula may be configured as follows using DSB.
In other words, compared to the previous formula, Ω20 MHz may be replaced with “sum of bit number of 0 in DSB”.
Here, “sum of bit number of 0 in DSB” represents to the number of (sub-) channels of the non-punctured 20 MHz indicated through DSB within BW (i.e., bandwidth of PPDU)). For example, a case that the DSB is at 80 MHz means that the second 20 mhz channel is punctured. Here, the number of non-punctured channels corresponds to 3, which is the number of 0s. Therefore, “sum of bit number of 0 in DSB” is set to 3.
A non-AP STA transmitting an NDP feedback report response may configure the RU_TONE_SET_INDEX of the TXVECTOR for transmitting a HE TB PPDU in response to an NFRP trigger frame using any of the above formulas.
When the tone set index is reordered through DSB as above, the number of STAs that transmit a response (i.e., NDP feedback report response) in response to the NFRP trigger frame may be calculated as follows.
Here, Ω20 MHz is the number of 20 MHz (sub) channels that are not punctured within the BW (i.e., the bandwidth of the PPDU). In addition, the MultiplexingFlag is the value of the Number Of Spatially Multiplexed Users subfield (i.e., Multiplexing Flag subfield) (see
Alternatively, the number of STAs that transmit a response (i.e., NDP feedback report response) in response to the NFRP trigger frame may be calculated using DSB as follows.
In other words, compared to the previous formula, Ω20 MHZ may be replaced by “sum of bit number of 0 in DSB”.
As another example, an allocation method may be considered using the RU tone set index according to the existing BW, but excluding the RU tone index corresponding to the punctured 20 MHz. In other words, according to the previously described method, the RU tone index was not set for the punctured 20 MHz, but according to this method, the RU tone index is set in the punctured 20 MHz, but may not actually be assigned to the STA.
As described above, the EHT AP/STA may recognize/identify information on punctured 20 MHz within the BW using DSB in the BSS. Therefore, using the information on the punctured 20 MHz, the RU tone set index for the response to the NFRP (i.e., NDP feedback report response) may be set as shown in Table 8 below.
Table 8 illustrates that the RU tone set index is set for a punctured 80 MHz channel.
The tone set index for the NFRP response (i.e., NDP feedback report response) may be set sequentially without considering the punctured 20 MHz(s). However, the tone set index set in the punctured 20 MHz(s) or puntured subchannel may not be used (i.e., may not be assigned to the STA).
As in the case of continuous BW (i.e., not punctured) as above, the RU tone set index may be used (set) in the punctured BW, herein, the tone set index corresponding to (set) punctured 20 MHz(s) may not be assigned to the STA.
Herein, the RU tone set index corresponding (set) to the punctured 20 MHz (sub) channel may be sequentially mapped and used for the AID of the STA.
In the case of punctured 80 MHz as in the above example, the RU tone set index may be determined as follows.
That is, for STAs with AIDs from which values range from 1 to 18, an RU tone set index of 1 to 18 may be assigned depending on the AID.
That is, for STAs with AIDs from which values range from 19 to 36, an RU tone set index of 37 to 54 may be assigned depending on the AID.
That is, for STAs with AIDs from which values range from 37 to 54, an RU tone set index of 55 to 72 may be assigned depending on the AID.
In the above description of the present disclosure, for convenience of explanation, the case of puncturing at 80 MHz BW was mainly explained as an example, but this is only one example. The method proposed in the present disclosure may be equally applied to the case punctured at 160 MHz BW or the case punctured at 320 MHz BW.
Referring to
Herein, the AP may transmit an NFRP trigger frame to determine the buffer status and/or whether data is transmitted from multiple STAs.
Additionally, the NFRP trigger frame may be broadcast, but the STAs for which a response to the NFRP trigger frame is requested (i.e., scheduled) may be determined by the Starting AID subfield in the User Info field in the NFRP trigger frame.
According to Embodiment 1 above, referring to
The STA transmits a PPDU carrying the NDP feedback report response to the AP in response to the NFRP trigger frame (S1702).
Herein, the STAs that received the NFRP trigger frame may determine whether an NDP feedback report response is requested (i.e., scheduled) using the value of the Starting AID subfield in the User Info field in the NFRP trigger frame.
Additionally, as described above, the scheduled STA may transmit an NDP feedback report response to the AP in order to signal to the AP that the STA is in the awake state and that there may be frames in the queue for the UL MU. Otherwise, the STA may not transmit any response to the AP.
Here, the NDP feedback report response (i.e., PPDU carrying the response) may be transmitted on the frequency resource (e.g., tones or subcarriers) corresponding to the tone set index assigned to the STA.
Additionally, when one or more subchannels (e.g., 20 MHz subchannel) within the bandwidth of the PPDU are punctured, the tone set index assigned to the STA may be determined not to include the frequency resource in the one or more punctured subchannels. Here, one or more subchannels to be punctured may be indicated from the AP through a disabled subchannel bitmap, and the disabled subchannel bitmap may be transmitted through a beacon frame or EHT operation element.
To this end, according to Embodiment 1, the tone set index information may be explicitly transmitted to the STA(s) in the NFRP trigger frame.
Alternatively, the AP may not explicitly inform STAs of the tone set index assigned to each STA, and each STA may derive the tone set index assigned to it based on predefined rules/formulas, etc.
For example, according to Embodiment 2 above, no tone set index may be set/mapped to one or more punctured subchannels, and tone set indices may be set/mapped only to non-punctured subchannels. In addition, a tone set index assigned to the STA may be determined from among the set/mapped tone set indexes. In this case, the STA may determine the tone set index assigned to the STA based on the number of one or more punctured subchannels and the AID of the STA.
Alternatively, according to Embodiment 2 above, even though tone set indices are set/mapped in one or more punctured subchannels, a tone set index assigned to the STA may be determined among the remaining tone set indexes excluding the tone set index for one or more punctured subchannels.
Referring to
Herein, the AP may transmit an NFRP trigger frame to determine the buffer status and/or whether data is transmitted from multiple STAs.
Additionally, the NFRP trigger frame may be broadcast, but the STAs for which a response to the NFRP trigger frame is requested (i.e., scheduled) may be determined by the Starting AID subfield in the User Info field in the NFRP trigger frame.
According to Embodiment 1 above, referring to
The AP receives a PPDU carrying the NDP feedback report response from the STA in response to the NFRP trigger frame (S1802).
Herein, the STAs that received the NFRP trigger frame may determine whether an NDP feedback report response is requested (i.e., scheduled) using the value of the Starting AID subfield in the User Info field in the NFRP trigger frame.
Additionally, as described above, the scheduled STA may transmit an NDP feedback report response to the AP in order to signal to the AP that the STA is in the awake state and that there may be frames in the queue for the UL MU. Otherwise, the STA may not transmit any response to the AP. Therefore, the AP that receives the NDP feedback report response from the STA may recognize/identify which STA has the frame for UL MU transmission.
Here, the NDP feedback report response (i.e., PPDU carrying the response) may be transmitted on the frequency resource (e.g., tones or subcarriers) corresponding to the tone set index assigned to the STA.
Additionally, when one or more subchannels (e.g., 20 MHz subchannel) within the bandwidth of the PPDU are punctured, the tone set index assigned to the STA may be determined not to include the frequency resource in the one or more punctured subchannels. Here, one or more subchannels to be punctured may be indicated from the AP through a disabled subchannel bitmap, and the disabled subchannel bitmap may be transmitted through a beacon frame or EHT operation element.
To this end, according to Embodiment 1, the tone set index information may be explicitly transmitted to the STA(s) in the NFRP trigger frame.
Alternatively, the AP may not explicitly inform STAs of the tone set index assigned to each STA, and each STA may derive the tone set index assigned to it based on predefined rules/formulas, etc.
For example, according to Embodiment 2 above, no tone set index may be set/mapped to one or more punctured subchannels, and tone set indices may be set/mapped only to non-punctured subchannels. In addition, a tone set index assigned to the STA may be determined from among the set/mapped tone set indexes. In this case, the STA may determine the tone set index assigned to the STA based on the number of one or more punctured subchannels and the AID of the STA.
Alternatively, according to Embodiment 2 above, even though tone set indices are set/mapped in one or more punctured subchannels, a tone set index assigned to the STA may be determined among the remaining tone set indexes excluding the tone set index for one or more punctured subchannels.
Embodiments described above are that elements and features of the present disclosure are combined in a predetermined form. Each element or feature should be considered to be optional unless otherwise explicitly mentioned. Each element or feature may be implemented in a form that it is not combined with other element or feature. In addition, an embodiment of the present disclosure may include combining a part of elements and/or features. An order of operations described in embodiments of the present disclosure may be changed. Some elements or features of one embodiment may be included in other embodiment or may be substituted with a corresponding element or a feature of other embodiment. It is clear that an embodiment may include combining claims without an explicit dependency relationship in claims or may be included as a new claim by amendment after application.
It is clear to a person skilled in the pertinent art that the present disclosure may be implemented in other specific form in a scope not going beyond an essential feature of the present disclosure. Accordingly, the above-described detailed description should not be restrictively construed in every aspect and should be considered to be illustrative. A scope of the present disclosure should be determined by reasonable construction of an attached claim and all changes within an equivalent scope of the present disclosure are included in a scope of the present disclosure.
A scope of the present disclosure includes software or machine-executable commands (e.g., an operating system, an application, a firmware, a program, etc.) which execute an operation according to a method of various embodiments in a device or a computer and a non-transitory computer-readable medium that such a software or a command, etc. are stored and are executable in a device or a computer. A command which may be used to program a processing system performing a feature described in the present disclosure may be stored in a storage medium or a computer-readable storage medium and a feature described in the present disclosure may be implemented by using a computer program product including such a storage medium. A storage medium may include a high-speed random-access memory such as DRAM, SRAM, DDR RAM or other random-access solid state memory device, but it is not limited thereto, and it may include a nonvolatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices or other nonvolatile solid state storage devices. A memory optionally includes one or more storage devices positioned remotely from processor(s). A memory or alternatively, nonvolatile memory device(s) in a memory include a non-transitory computer-readable storage medium. A feature described in the present disclosure may be stored in any one of machine-readable mediums to control a hardware of a processing system and may be integrated into a software and/or a firmware which allows a processing system to interact with other mechanism utilizing a result from an embodiment of the present disclosure. Such a software or a firmware may include an application code, a device driver, an operating system and an execution environment/container, but it is not limited thereto.
A method proposed by the present disclosure is mainly described based on an example applied to an IEEE 802.11-based system, 5G system, but may be applied to various WLAN or wireless communication systems other than the IEEE 802.11-based system.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0106929 | Aug 2021 | KR | national |
This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2022/012079, filed on Aug. 12, 2022, which claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2021-0106929, filed on Aug. 12, 2021, and also claims the benefit of U.S. Provisional Application No. 63/237,108, filed on Aug. 25, 2021, the contents of which are all incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/012079 | 8/12/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63237108 | Aug 2021 | US |
