KR20200116674A - Method of processing discovery frame for wakeup radio stations in wideband wireless lan networks - Google Patents

Abstract

The present invention provides a device, system, and wireless LAN communication method for a wireless communication LAN performing a power saving operation using a low-power wake-up receiver in a wireless LAN environment. To this end, the wireless LAN system comprises one or more basic service sets (BSSs).

Description

Method of processing discovery frame of wakeup radio terminal in wireless LAN broadband environment {METHOD OF PROCESSING DISCOVERY FRAME FOR WAKEUP RADIO STATIONS IN WIDEBAND WIRELESS LAN NETWORKS}

The present invention relates to a method for improving transmission efficiency, and more particularly, to various methods, apparatuses, and systems for improving transmission efficiency by proposing an improved channel access method in a wireless LAN.

Recently, as the spread of mobile devices expands, a wireless LAN technology capable of providing fast wireless Internet services to them is in the spotlight. Wireless LAN technology is a technology that enables mobile devices such as smart phones, smart pads, laptop computers, portable multimedia players, embedded devices, etc. to access the Internet wirelessly at home, business, or in a specific service area based on wireless communication technology in a short distance. to be.

Since IEEE (Institute of Electrical and Electronics Engineers) 802.11 supported the initial wireless LAN technology using 2.4GHz frequency, various technology standards are being commercialized or developed. First, IEEE 802.11b supports a communication speed of up to 11Mbps while using a frequency of the 2.4GHz band. IEEE 802.11a, commercialized after IEEE 802.11b, has reduced the effect of interference compared to the frequency of the 2.4GHz band, which is quite congested by using the frequency of the 5GHz band instead of the 2.4GHz band, and uses OFDM technology to maximize the communication speed. Improved to 54Mbps. However, IEEE 802.11a has a short communication distance compared to IEEE 802.11b. And IEEE 802.11g, like IEEE 802.11b, implements a communication speed of up to 54Mbps using a frequency of the 2.4GHz band, and has received considerable attention because it satisfies backward compatibility. Have the upper hand.

In addition, IEEE 802.11n is a technical standard established to overcome the limitation on communication speed that has been pointed out as a vulnerability in wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with a data processing speed of 540 Mbps or more, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize the data rate. It is based on MIMO (Multiple Inputs and Multiple Outputs) technology. In addition, this standard can use a coding scheme in which multiple duplicate copies are transmitted to increase data reliability.

As the spread of wireless LAN becomes active and applications using it become diversified, the need for a new wireless LAN system to support a higher throughput (Very High Throughput, VHT) than the data processing speed supported by IEEE 802.11n emerges. Became. Among them, IEEE 802.11ac supports a wide bandwidth (80MHz~160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backward compatibility with existing 2.4GHz band products, the initial 11ac chipsets will also support operation in the 2.4GHz band. In theory, according to this standard, the wireless LAN speed of multiple stations is at least 1 Gbps, and the maximum single link speed is at least 500 Mbps. This is achieved by extending the concept of the air interface adopted by 802.11n, such as a wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high density modulation (up to 256 QAM). In addition, there is IEEE 802.11ad as a method of transmitting data using a 60GHz band instead of the existing 2.4GHz/5GHz. IEEE 802.11ad is a transmission standard that provides a maximum speed of 7Gbps using beamforming technology, and is suitable for high bit rate video streaming such as large amounts of data or uncompressed HD video. However, the 60GHz frequency band has a disadvantage that it is difficult to pass through obstacles and can only be used between devices in a short distance.

On the other hand, in recent years, as a next-generation wireless LAN standard after 802.11ac and 802.11ad, discussions have been continuously made to provide a high-efficiency and high-performance wireless LAN communication technology in a high-density environment. That is, in a next-generation wireless LAN environment, communication with high frequency efficiency must be provided indoors/outdoors in the presence of a high-density station and an AP (Access Point), and various technologies are required to implement this.

In addition, to develop technology to increase the speed and efficiency of wireless LAN, extend the battery life of mobile devices equipped with wireless LAN, and to install wireless LAN in devices that operate based on very limited strategic sources such as batteries, It is necessary to develop a wireless LAN power saving technique. Previously proposed wireless LAN power saving techniques are methods of periodically entering the sleep mode to reduce power. In this case, the higher the power saving efficiency of the device, the longer the device wakes up, so communication with the device is more effective. There is a disadvantage of being delayed. To solve this problem, a study on a power saving method using a separate low-strategy wake-up receiver is needed.

As described above, an object of the present invention is to perform a power saving operation using a low-power wake-up receiver in a wireless LAN environment.

According to an embodiment of the present invention, an apparatus, a system, and a wireless LAN communication method for a wireless LAN may be provided.

An efficient power saving operation is performed through the wake-up receiver in the wireless LAN, and the subsequent data exchange sequence can be efficiently performed after the device wakes up.

1 is a diagram showing a wireless LAN system according to an embodiment of the present invention.
2 is a diagram showing a wireless LAN system according to another embodiment of the present invention.
3 is a block diagram showing the configuration of a station according to an embodiment of the present invention.
4 is a block diagram showing the configuration of an access point according to an embodiment of the present invention.
5 illustrates detailed operations of a PS mode of a wireless LAN according to an embodiment of the present invention.
6 shows an example of a network configuration in which a power save function based on Wake Up Radio (WUR) proposed in the present invention operates.
7 is a diagram illustrating an operation process between a WUR AP and an STA according to an embodiment of the present invention.
8 illustrates the configuration of WUR Capabilities according to an embodiment of the present invention.
9 shows the configuration of a WUR Operation element according to an embodiment of the present invention.
10 shows the structure of a WUR Mode Action frame according to an embodiment of the present invention.
11 illustrates a WUR identifier space according to an embodiment of the present invention.
12 shows the format of a WUR PPDU (PCLP Protocol Data Unit) according to an embodiment of the present invention.
13 illustrates a specific WF format according to an embodiment of the present invention.
14 shows a specific format of a VL WUF according to an embodiment of the present invention.
15 illustrates a format of a WUR Discovery frame according to an embodiment of the present invention.

The terms used in the present specification have been selected as currently widely used general terms as possible while considering the functions of the present invention, but this may vary according to the intention, custom, or the emergence of new technologies of the skilled person in the art. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in the description of the corresponding invention. Therefore, it should be noted that the terms used in the present specification should be interpreted based on the actual meaning of the term and the entire contents of the present specification, not a simple name of the term.

Throughout the specification, when a configuration is said to be “connected” with another configuration, this is not only the case that it is “directly connected”, but is also “electrically connected” with other components in the middle. Includes cases. In addition, when a certain component "includes" a specific component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary. In addition, the limitations of “above” or “less than” based on a specific threshold value may be appropriately replaced with “exceeding” or “less than”, respectively, according to embodiments.

1 shows a wireless LAN system according to an embodiment of the present invention. The wireless LAN system includes one or more Basic Service Set (BSS), which represents a set of devices that can communicate with each other by successfully synchronizing. In general, the BSS can be classified into an infrastructure BSS (infrastructure BSS) and an independent BSS (IBSS), and FIG. 1 shows an infrastructure BSS among them.

As shown in Figure 1, the infrastructure BSS (BSS1, BSS2) provides one or more stations (STA-1, STA-2, STA-3, STA-4, STA-5), and distribution service. An access point (PCP/AP-1, PCP/AP-2), which is a providing station, and a distribution system (DS) that connects multiple access points (PCP/AP-1, PCP/AP-2). Include.

A station (STA) is an arbitrary device including a medium access control (MAC) and a physical layer interface to a wireless medium in accordance with the IEEE 802.11 standard. Non-AP) stations as well as access points (APs). In addition, in the present specification, the term'terminal' may be used as a concept including all wireless LAN communication devices such as a station and an AP. The station for wireless communication includes a processor and a transceiver, and may further include a user interface unit and a display unit according to an embodiment. The processor may generate a frame to be transmitted through a wireless network or process a frame received through the wireless network, and may perform various other processes for controlling a station. The transceiver is functionally connected to the processor and transmits and receives frames through a wireless network for the station.

An Access Point (AP) is an entity that provides access to a distribution system (DS) via a wireless medium for a station associated with it. In an infrastructure BSS, communication between non-AP stations is in principle performed via an AP, but direct communication is also possible between non-AP stations when a direct link is established. On the other hand, in the present invention, the AP is used as a concept including a Personal BSS Coordination Point (PCP), and broadly, a centralized controller, a base station (BS), a node-B, a base transceiver system (BTS), or a site It may include all concepts such as a controller.

A plurality of infrastructure BSSs may be interconnected through a distribution system (DS). In this case, a plurality of BSSs connected through the distribution system is referred to as an extended service set (ESS).

2 shows an independent BSS, which is a wireless LAN system according to another embodiment of the present invention. In the embodiment of FIG. 2, duplicate descriptions of parts that are the same as or corresponding to the embodiment of FIG. 1 will be omitted.

Since the BSS-3 shown in FIG. 2 is an independent BSS and does not include an AP, all stations STA-6 and STA-7 are not connected to the AP. Independent BSS is not allowed to access the distribution system and forms a self-contained network. In the independent BSS, each of the stations STA-6 and STA-7 may be directly connected to each other.

3 is a block diagram showing the configuration of a station 100 according to an embodiment of the present invention.

As shown, the station 100 according to the embodiment of the present invention includes a processor 110, a network interface card (NIC, 120), a user interface unit 140, a display unit 150, and a memory 160. can do.

First, the network interface card 120 is a module for performing wireless LAN access, and performs packet transmission and reception for the station 100. The network interface card 120 may be built-in or externally provided in the station 100, and may include at least one network interface card module using different frequency bands according to embodiments. For example, the network interface card may include network interface card modules of different frequency bands such as 2.4GHz, 5GHz, and 60GHz. According to an embodiment, the station 100 may include a network interface card module using a frequency band of 6 GHz or higher and a network interface card module using a frequency band of 6 GHz or lower. Each network interface card module may perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the corresponding network interface card module. The network interface card 120 may operate only one network interface card module at a time or may simultaneously operate a plurality of network interface card modules according to the performance and requirements of the station 100. When the station 100 includes a plurality of network interface card modules, each network interface card module may be provided in an independent form or may be integrated into one chip.

Next, the user interface unit 140 includes various types of input/output means provided in the station 100. That is, the user interface unit 140 may receive a user's input using various input means, and the processor 110 may control the station 100 based on the received user input. In addition, the user interface unit 140 may perform output based on a command of the processor 110 using various output means.

Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects such as content executed by the processor 110 or a user interface based on a control command of the processor 110. In addition, the memory 160 stores a control program used in the station 100 and various data corresponding thereto. The control program may include an access program necessary for the station 100 to access an AP or an external station.

The processor 110 of the present invention can execute various commands or programs and process data inside the station 100. In addition, the processor 110 controls each unit of the station 100 described above, and may control data transmission/reception between the units. According to an embodiment of the present invention, the processor 110 may execute a program for accessing an AP stored in the memory 160 and receive a communication setup message transmitted by the AP. Also, the processor 110 may read information on the priority condition of the station 100 included in the communication setup message, and request access to the AP based on the information on the priority condition of the station 100. A specific embodiment of this will be described later.

The station 100 shown in FIG. 3 is a block diagram according to an embodiment of the present invention, and the separated blocks are shown by logically distinguishing elements of a device. Accordingly, the elements of the device described above may be mounted as one chip or as a plurality of chips according to the design of the device. In addition, in the embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, may be selectively provided in the station 100.

4 is a block diagram showing the configuration of an AP 200 according to an embodiment of the present invention.

As shown, the AP 200 according to the embodiment of the present invention may include a processor 210, a network interface card 220, and a memory 260. In FIG. 4, redundant descriptions of parts of the configuration of the AP 200 that are the same as or corresponding to the configuration of the station 100 of FIG. 3 will be omitted.

Referring to FIG. 4, the AP 200 according to the present invention includes a network interface card 220 for operating a BSS in at least one frequency band. As described above in the embodiment of FIG. 3, the network interface card 220 of the AP 200 may also include a plurality of network interface card modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may be provided with two or more network interface card modules among different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a network interface card module using a frequency band of 6 GHz or higher and a network interface card module using a frequency band of 6 GHz or lower. Each network interface card module may perform wireless communication with a station according to a wireless LAN standard of a frequency band supported by the corresponding network interface card module. The network interface card 220 may operate only one network interface card module at a time or may simultaneously operate a plurality of network interface card modules according to the performance and requirements of the AP 200.

Next, the memory 260 stores a control program used in the AP 200 and various data according thereto. Such a control program may include an access program that manages access of the station. In addition, the processor 210 controls each unit of the AP 200 and may control data transmission/reception between the units. According to an embodiment of the present invention, the processor 210 may execute a program for accessing a station stored in the memory 260 and transmit a communication setting message for one or more stations. In this case, the communication setup message may include information on the access priority condition of each station. In addition, the processor 210 performs connection setup according to the station's connection request. A specific embodiment of this will be described later.

5 illustrates detailed operations of a PS mode of a wireless LAN according to an embodiment of the present invention.

In wireless LAN, a power management function is defined as a method to reduce power consumption of a terminal. In the Power Management (PM) function, the operation of the terminal is divided into two types: Active/Power Save (PS) mode. In the active mode, the terminal is always awake and can transmit and receive wireless LAN data at any time. However, in the PS mode, the terminal can operate in two states, awake/doze, the awake state means a state in which wireless LAN data can be transmitted/received, and the doze state means a state in which wireless LAN data cannot be transmitted and received. Therefore, if the terminal is in the doze state, since the AP cannot receive the data sent to the corresponding terminal, the AP must know whether the terminal is likely to operate in the doze state, and thus all terminals belonging to its BSS Which of these Active/PS modes is operated should be recorded. To this end, when the UE switches its own PM mode, it must notify the AP of the mode change through the setting of the Power Management (PM) subfield of the Frame Control Field of the data it sends. The switching of the PM mode of the terminal occurs after the completion of the transmission sequence initiated by the terminal, and a sequence requesting an immediate response must be used. If the terminal transmits data with the PM subfield set to 1 and then successfully receives an immediate response such as an Ack/BA frame responding thereto, the terminal must operate in PS mode from that point, and the terminal sets the PM subfield to 0. When the immediate response such as an Ack/BA frame responding to it after transmitting the data set to is successfully received, the terminal must operate in Active mode from that point.

In the existing wireless LAN, a number of detailed protocols are defined for a terminal operating in PS mode. Among them, a protocol that does not go through a separate scheduling process, two of which are normal power save mode and Unscheduled Automatic Power Save Delivery (U-APSD). Three detailed protocols are defined.

In the PS mode, the UE has no restrictions on uplink transmission, and even if it is operating in the PS mode, it can switch from the doze state to the awake state at any time to perform uplink transmission, but when receiving downlink transmission, when there is no separate scheduling When the AP attempts downlink transmission, since it is not sure whether the receiving terminal operating in the PS mode is an awake state or a doze state, transmission/reception can be performed only under a predetermined condition. Therefore, both PS protocols define operations based on downlink transmission conditions.

In the normal power save mode, when the terminal successfully switches from the active mode to the PS mode, the AP cannot directly transmit the data to be transmitted to the corresponding terminal and stores it in a buffer. It can be indicated that there is data to the corresponding terminal in the TIM element that is always inserted into the beacon that is transmitted periodically thereafter. When the terminal in the PS mode receives the beacon in the awake state and the part corresponding to its AID in the TIM element is activated, it can perform EDCA backoff with the AC_BE class to transmit the PS-poll, and the AP receiving the PS-poll Can deliver either an Ack frame or a stored DL buffered BU (Bufferable Unit). The terminal that has received an Ack response must maintain the awake state until the AP transmits the BU to the new TXOP. If the More Data field of the BU transmitted by the AP is activated, the UE must transmit an additional PS-poll. The terminal does not have to check every beacon, but it must wake up and check the beacon every period set by the DTIM period.

Whether to use U-APSD is set for each AC in the link setup step such as the (Re) association step, and the AC of the terminal using U-APSD becomes trigger-enabled AC, and the same AC of the AP is deliver- It is considered as enabled AC. The AC using the U-APSD does not check the TIM element of the Beacon transmitted by the AP, and the terminal directly transmits a trigger frame at any point in time to open a service period and receive a DL buffered BU. At this time, the trigger frame is one of QoS Data and Null frames transmitted from the trigger-enabled AC. A service period for the UE is formed from the time when the immediate response of the AP is received with respect to the trigger frame transmitted by the UE, and the AP may transmit a buffered BU. Therefore, the UE must maintain the awake state until the time when EOSP (End Of Service Period) is activated in the BU transmitted by the AP or the time when the predefined SP period ends. When the terminal uses U-APSD for some of the ACs, the presence of the buffered BU of the corresponding AC is not displayed on the TIM, and only the presence of the buffered BU of the AC not using the U-APSD is displayed on the TIM. Therefore, in order to receive the buffered BU of AC (non trigger-enabled (TE) AC, non delivery-enabled (DE) AC) that does not use U-APSD, the terminal must check the TIM and operate the normal power save mode. Must follow.

6 shows an example of a network configuration in which a power save function based on Wake Up Radio (WUR) proposed in the present invention operates.

The WUR network is managed by a WUR AP that can wake up by sending a WUR frame (WF) to WUR terminals. Since the WUR AP and the terminal are combined with a wireless LAN device such as 802.11a/b/g/n/ac/ax, which is a standard wireless LAN standard, it can be used in one network with general wireless LAN terminals that do not have the WUR function. Can coexist.

An AP supporting WUR basically has an 802.11 Transceiver (TR) supporting OFDM-based 802.11 communication, and may additionally include a separate WURx (Wakeup Receiver) capable of receiving an OOK-based WUR frame (WUR frame). In this case, in order for the AP to support WUR, it must be able to transmit (TX) a WUR frame (WF) using an 802.11 TR. Incidentally, when the WURx is provided, it has the function of receiving (RX) WF. WURx may be configured as a separate receiving device, and may be implemented in the form of a function in the same device as the 802.11 TR.

A terminal supporting WUR also basically includes an 802.11 TR supporting 802.11 communication, and also basically includes a separate WUR capable of receiving WF. At this time, the 802.11 TR and WURx have an internal interface, through which the 802.11 TR sets parameters necessary for the operation of the WURx, and the WURx sends a wakeup signal when the 802.11 TR enters the power save mode and receives WF from the outside. Wake up the 802.11 TR, Primarily Connected Radio (PCR). In this case, additionally, an interface for transmitting information received through the WF from the outside to the PCR may exist.

The WUR AP must be able to efficiently wake up only the STA entering the WUR-based power save mode in its BSS. To this end, each STA must be able to wake up from the power save mode when a WF including a unique ID is received through WURx. In addition, during this process, WUR STAs belonging to the corresponding BSS or other BSS should not wake up unnecessarily.

7 is a diagram illustrating an operation process between a WUR AP and an STA according to an embodiment of the present invention.

In order for the UE to perform the WUR-related operation, it is necessary to exchange information about whether the WUR operation is possible between the AP and the AP at the PCR stage. Accordingly, in the initial link setup process performed when the WUR terminal initially associates with the corresponding BSS, the WUR capabilities element may be included and transmitted through a probe request, authentication request, or association request frame. The corresponding element may include information indicating a function capable of operating as a WUR terminal. The above-described process may be transmitted together in the form of an element during the capability negotiation process, or may be a process of transmitting and receiving in a separate action frame. During the link setup process, an AP capable of performing a WUR-related operation may insert a WUR Capabilities element and a WUR Operation element into a Probe Response, Association Response, or Authentication Response frame and transmit. Also, the corresponding elements are included in the Beacon, etc. and transmitted.

The WUR terminal may perform a setup process for an actual WUR-related operation between the AP supporting WUR and after the association. When the terminal finishes the PCR operation after the association and wants to operate in the WUR mode to perform the power-saving function, the AP and the WUR mode related action frame can be exchanged. The Action frame is an Action frame including a WUR Mode element, and may be a WUR Mode Request or WUR Mode Response frame. The action frame is exchanged to set parameters related to the actual operation of the WUR. The action frame is exchanged through PCR, and Ack can be requested from the receiver. If the AP, which normally receives the WUR Action frame, needs to change information for a request related to a WUR operation or requires an additional verification process, an additional WUR Action frame may be transmitted. The corresponding action frame exchange process may be repeated until mutual agreement on parameters is reached. After completing the WUR parameter agreement process with the AP, the terminal can operate in the WUR mode, and from this point on, it can perform the operation using WURx when changing its power state to the doze state according to its Power Management mode operation.

Specifically, a terminal operating in the WUR mode may operate in one of two states: WUR awake and WUR doze. The WUR awake state means a state in which the UE can recognize and receive an OOK-based WUR frame, and the WUR doze state means a state in which the WUR frame cannot be received. The two states operate independently of the Awake/Doze state of the PS Mode. However, when the terminal is using the WUR mode and operates in the Doze state of the PS mode, the condition that it must operate in the WUR awake state to receive the WUR frame may apply. Therefore, when the AP using the PS Mode and WUR Mode is expected to operate in the Doze state, the AP must transmit the WF before transmitting the WLAN frame to induce a wakeup operation. In addition, from the point when the terminal starts to use the WUR mode, the previously defined scheduling-related operations are postponed until the point at which the terminal exits the WUR mode except for specific exception conditions.

The terminal operating in the WUR mode has received the WUF from the WUR AP, and the WUF includes the WUR ID (WID), the identifier of the terminal in the WUR mode, or includes the Group ID that includes itself, or all WUR terminals of the corresponding BSS In the case of instructing the wake-up of WUF, the internal signal to wake the PCR device is transmitted after temporarily storing the information included in the WUF. After the PCR wakes up, the stored packet number and TSF information can be transmitted to the PCR through the interface through which WUR and PCR exchange information.

In the case of WUF transmission, the transmission time is very long because 1 bit is transmitted through one OFDM symbol. In addition, since the PCR transition delay between the WUF reception and the PCR from the sleep mode to the active mode may be several milliseconds or more, it may be necessary to check whether a wake-up operation has been successfully performed between the WUR AP and the terminal. If the wake-up operation is completed without the corresponding verification process and the data transmission process in the PCR stage is performed, it may be very inefficient because long-length data transmission becomes meaningless or the entire wake-up process must be performed again. To prevent this, a wake-up confirmation process can be performed using a PCR that can exchange information relatively quickly immediately after WF is received. Immediately after the PCR wakes up, the UE may transmit an Awake Indication to the AP indicating that it has successfully awakened. Awake Indication must be transmitted according to the channel access method of PCR, and may be a separate control frame defined for WUR operation or a frame existing in the existing wireless LAN standard such as Ps-poll. If the AP wants to receive Awake Indication after a specific time elapses after wake-up, it may attempt to access the channel from the time point elapsed. The specific time may be included in the WUR Capability element included in the probe response or association response, and may be transmitted through the WUR Mode response. The AP receiving the Awake Indication may respond with an immediate response frame after a predetermined time in response to it. Immediate response may be a general immediate response frame such as an Ack frame, or a control frame separately defined for WUR operation, and may be QoS data.

Until the terminal successfully completes the Awake indication transmission, the AP cannot know whether the terminal has successfully performed the wake up operation by receiving the WUF. In addition, since the PCR transition delay, which is the time the UE wakes up the PCR, may be longer than several milliseconds, during the PCR transition delay, the AP retransmits the same WF or sends the WF with a changed detailed parameter to the same UE in order to increase the probability of wakeup success. This can happen. Therefore, even if the terminal is successfully receiving the WF and is performing the wake-up operation, the WURx can be maintained in power until the time when an immediate response is received from the AP by successfully transmitting the Awake Indication without turning off the power of the WURx.

If the terminal transmits data that does not request an immediate response in the frame of Awake Indication, it may be difficult to determine whether the wakeup operation has been successfully completed. Therefore, when the UE transmits an Awake Indication, a condition that a Control frame, an Action frame, and an Ack Policy requesting an immediate response must transmit a QoS Data/Null frame set as Normal Ack or Implicit Block Ack may be added. In addition, after transmitting the WF to one or more terminals from the AP side, it is also possible to directly transmit a frame asking whether the terminal wakes up. Therefore, even in this case, a condition that a frame requesting an immediate response must be transmitted may be added.

If the AP does not receive the Awake Indication from the time when the WF is transmitted to the time when the timer expires by starting the timer, it may stipulate that the transmitted WF has failed. In this case, since the target terminal of the WF changes its operation from the Doze state to the awake state, it is recommended to detect the channel after the wake-up operation to catch the NAV, or to perform uplink transmission until the time elapsed by the predefined NAVSyncDelay. There is an initial CCA condition to prohibit. Therefore, the timer set by the AP must be set to a larger value including the PCR transition delay and NAVSyncDelay of the terminal. If the WF transmission fails because the timer expires, the AP can retransmit the WF.

Since the NAVSyncDelay of the terminal is a value for the internal operation of the terminal, it may generally be impossible for other terminals to know the value. Accordingly, the terminal performing WUR operation can share its NAVSyncDelay value with the AP through the PCR frame. Specifically, the terminal may transmit by inserting its own NAVSyncDelay value into the WUR Capabilities element. As another method, the UE may insert and transmit the WUR operation element transmitted to the AP. In this case, the AP, which has received the NAVSyncDelay value in the above-described manner, should be set to a larger value including the PCR transition delay and NAVSyncDelay received from the terminal in applying the timer to the terminal.

As another method, when the UE notifies the PCR transition delay to the WUR Capabilities element, the hardware transition delay may be set by adding an internally configured NAVSyncDelay value. In this case, the AP should be set to a value larger than the PCR transition delay transmitted from the terminal in applying the timer to the terminal.

As another method, a maximum NAVSyncDelay value requested by the AP may be specified in one of the PCR elements transmitted from the AP to the UE. For example, a corresponding value may be included in the WUR Capabilities element or WUR Operation element or WUR Mode element transmitted by the AP. In this case, a terminal operating with a NAVSyncDelay greater than the specified value must change its NAVSyncDelay value to a value smaller than the specified value when it wants WUR Mode operation. The changed value may be restored to the original value when the terminal exits the WUR mode. Alternatively, only a terminal having a value smaller than the NAVSyncDelay specified from the AP may be allowed to operate in the WUR mode. When the above embodiment is followed, the AP must set a value larger than the sum of the NAVSyncDelay value and PCR transition delay specified by the AP when applying the timer.

In the above embodiment, when the AP announces the NAVSyncDelay value, if the terminal changes the NAVSyncDelay value, there is a possibility that the operation of the existing wireless LAN transceiver is also affected in a situation where the terminal does not operate in the WUR mode. Therefore, when the NAVSyncDelay value indicated in the WUR Capabilities element or WUR Operation element or WUR Mode element is separately designated as the WUR NAVSyncDelay for wake-up operation, and the NAVSyncDelay value is used in the existing WLAN, the NAVSyncDelay value defined in the device is used. , WUR NAVSyncDelay value can be used only in a situation in which wakeup is performed by receiving a WUR frame. Therefore, the terminal waits for NAV synchronization for the maximum WUR NAVSyncDelay after the wireless LAN transceiver changes from doze to awake state, and if the NAV synchronization is not completed by the time elapsed, the channel is regarded as idle. You can participate in channel access.

8 illustrates the configuration of WUR Capabilities according to an embodiment of the present invention.

The WUR Capabilities element may follow the format of a general extension element of a WLAN. Therefore, after the information of the Element ID, Length, and Element ID extension is inserted, the actual capability-related information is inserted.

Among the information inserted into the WUR Capabilities element, the Supported Band specifies channels in which the AP or the terminal can transmit or receive WF.

Transition Delay represents the time it takes for the UE to convert the Doze state PCR to the Awake state after receiving the WUF. The AP transmitting the WUF may transmit PCR data after a longer period of time has passed in consideration of a delay specified by the target terminal. In addition, a WUF timeout criterion may be set based on the delay value.

VL WUR Frame Support specifies whether the terminal can receive a variable length WF. Therefore, a terminal in which the corresponding field is deactivated can only receive a fixed length (FL) WF transmitted with a predefined length without a frame body. When the terminal supports the WUR Discovery function, the WUR Discovery frame transmits additional information in the Frame Body field, so the field must be activated.

The WUR Group ID Support field specifies whether the terminal can receive the WUF indicated by the Group ID (GID) in addition to the WID. Also, if Group ID is supported, it informs whether or not the maximum number of Group ID is supported. The size of the Group ID bitmap transmitted when the AP allocates the GID to the terminal with the Group ID support number information may be determined. If the AP transmits the WUR Capabilities element, it may indicate the maximum number of Group IDs allocated by the BSS. If ID allocation of the WUR BSS is performed according to a predefined method, it is possible to implicitly allocate the WID of each terminal through the information. For example, if the GIDs of the corresponding BSS occupy a continuous WUR ID space based on the TXID of the AP, and then the WIDs are allocated in a predefined manner based on the AID of the PCR, the UE transmits the TXID of the AP and the AP. You can get your own WID value based on the Group ID Bitmap Size value. Therefore, when WUR ID is allocated in the above manner, the process of notifying the WID value in the WUR mode setting process can be omitted.

The Protected WUR Frame Support field indicates whether a WUR terminal can receive a WUR frame to which security using the Message Integrity Check technique is applied.

9 shows the configuration of a WUR Operation element according to an embodiment of the present invention.

The WUR Operation element specifies parameters used by the AP in the WUR service operating in the BSS. The parameters are parameters commonly applied to all terminals operating in the WUR mode, and parameters individually set for each terminal are set using a WUR mode element described later.

The WUR operation element follows a general WLAN element format, and parameters related to the WUR duty cycle may be included in the information part. First, a Minimum Wake-up Duration value that all terminals that perform duty-cycle operation must wake up to the minimum in their on-duration are inserted. In addition, Duty Cycle Period Unit information indicating the basic time unit of the duty-cycle period set using the WUR Mode element is included.

In addition, WUR Operating Class information is included to indicate information on which channels are available for the AP to transmit the WUR frame, and it is possible to inform which channel is actually being used for WUR service, including WUR Channel information.

In addition, it indicates information on a period in which WUR Beacon, which provides time synchronization of WUR terminals, including WUR Beacon Period information, is transmitted.

In addition, information indicating the closest Target WUR Beacon Transmission Time at a time point after the corresponding WUR Operation element is included.

In addition, in the following WUR parameter, a counter value indicating the latest value of the PCR BSS Parameter Update Counter that the AP inserts and transmits to the WUR Beacon may be included.

The following WUR Connectivity Timeout field refers to the maximum time that the UE can stay in the WUR mode without exchanging PCR frames with the AP. When the terminal operates in the WUR mode, the PCR can be continuously maintained in the Doze state until the AP requests wake-up or direct uplink transmission. Therefore, when the AP does not perform the PCR operation with the terminal for a long time, it may not be possible to distinguish whether the terminal is out of the BSS or continuously operates in the WUR mode. Therefore, a timer can be applied to prevent the above situation. Accordingly, the AP may consider that connectivity with the UE is disconnected when there is no exchange of PCR frames with the UE until the timeout value indicated by the timer reaches the timeout. The timer may be updated when a PCR frame is successfully exchanged with the terminal. In addition, when the terminal starts operation in the WUR mode, the timer may be applied from the time point when the Ack for the action frame that approves the WUR mode operation transmitted by the AP is transmitted.

If the UE does not transmit the PCR frame until the timer expires, the AP may cancel association with the UE. In a specific way, after transmitting the wakeup frame to the terminal, a disassociation request frame may be transmitted, and after transmitting the wakeup frame by another method, the association may be discarded when there is no response until a WUF timeout occurs. Alternatively, the association can be immediately revoked when the timer expires. When the terminal wants to continue the connection with the AP, it must attempt to transmit the PCR frame before the timer expires. If the frame cannot be transmitted before the timer expires, the AP and the association should be regarded as disconnected.

10 shows the structure of a WUR Mode Action frame according to an embodiment of the present invention.

The WUR Mode Action frame proposed in this embodiment follows the structure of a general action frame of a WLAN, and the Category field is set to WUR. In addition, the Action frame includes a WUR Mode element specifying which parameter to proceed with the WUR service when the terminal operates in the WUR mode.

The WUR Mode element follows the structure of a general WLAN element, and includes an Action Type field specifying for what purpose the action frame is transmitted. In the Action Type field, set to Enter WUR Mode Request/Enter WUR Mode Response/Enter WUR Mode Suspend Request/Enter WUR Mode Suspend Response/Enter WUR Mode Suspend/Exit WUR Mode, etc. according to the operation of the terminal and AP after the exchange of the action frame. Can be.

Thereafter, a WUR Mode Response Status field indicating whether the AP allows WUR Mode operation using a corresponding parameter in response to values included in the WUR Mode element received from the UE is located. The field may be set to Accept or Denied. In the following field, a WUR Parameters field specifying WUR parameters to be used in the WUR mode is located, and the field includes detailed parameters related to duty cycle and parameter values for each terminal related to various WUR services.

Thereafter, a WUR Parameter Control field indicating which item is included in the WUR Parameters field indicated by the WUR Mode element may exist in the field. In the WUR Parameter Control subfield, there may be a Group ID List Present subfield informing that the corresponding terminal has a GID assignment. If Group ID List Present is activated, Group ID bitmap information exists in the following WUR Parameters field. In addition, when one AP operates multiple BSSs that are not included in the multiple BSSID set, or does not generate a transmitter ID based on the BSSID of the corresponding BSS, a field that provides information to generate the transmitter ID or transmitter ID is provided. There may be an indicator indicating whether it exists or not. In more detail, there may be a BSSID present field indicating whether the BSSID exists, and a Transmitter ID Present field indicating the presence of transmitter ID information.

Thereafter, a WUR Parameters field indicating parameters to be used by the UE in the WUR mode is located in the field. The WUR Parameters field may include a WUR ID subfield indicating which identifier the UE will use in the WUR mode.

In the following field, a duty-cycle information subfield indicating a parameter related to the duty-cycle operation of the terminal is located.

If Group ID List Present is activated in the WUR Parameter Control field, the Group ID List field may exist. In one WUR network, the Group ID space is divided in a specific subset of spaces in a 12-bit ID space, and actual GID allocation information for each terminal can be reported in the form of a bitmap. Specifically, in WUR Capabilities, the Group ID Bitmap Size information set to a value smaller than the Maximum Group ID Bitmap Size specified by the terminal and the range information of the GID Bitmap are reported with the Starting Group ID (SGID) value, and actual allocation information through the subsequent Group ID Bitmap. Instruct. If the nth value of the bitmap is 1, it indicates that the GID corresponding to SGID+n is allocated to the terminal.

If the AP allocates GID and WID to contiguous spaces based on TXID to minimize WUR ID storage space and WUR ID allocation complexity in a specific implementation, if the TXID value determined by BSSID hashing is close to the 0xFFF value Consecutive group ID spaces may not be obtained with the same rule. In this case, separate GID and WID range allocation rules may be required according to the location of the TXID value. In order to prevent the above situation, a modulo operation of 2^12 units may be applied to GID allocation. For example, in a situation in which the nth value of the bitmap is 1, it may be indicated that the GID corresponding to (SGID+n)%(2^12) is allocated to the terminal.

If Transmitter ID Present is activated, a 12-bit value to be used by the corresponding WUR terminal as a transmitter ID or a 48-bit BSSID value for obtaining a transmitter ID through CRC operation may be indicated. In addition, a value of the Nontransmitter ID Index, which is a value used to derive the nontransmitter ID to be used by the corresponding terminal, may be indicated based on the transmitter ID obtained in the above process.

11 illustrates a WUR identifier space according to an embodiment of the present invention.

In the WUR network, the Transmitter ID (TXID) and Nontransmitter ID (NTXID) indicating the ID of the AP that is the sender of the WUR frame, the WUR ID (WID), the identifier of the individual WUR non-AP terminal, and the identifiers of a number of specific WUR non-AP terminals Various types of 12-bit identifiers, such as a group ID, can share the same 12-bit ID space. Therefore, the UE must distinguish whether individually addressed, group addressed, or broadcast through the ID field during WF transmission, so each identifier must not be duplicated within the same BSS. In addition, since the WUR identifier is not a unique ID of the device unlike the MAC address, a situation in which another terminal uses the same WUR ID in an external WUR network may also occur. If there is a terminal assigned the same WID or GID in the adjacent OBSS, or the OBSS AP uses the same TXID as its AP, and when receiving WUR Beacon or WF transmitted by the OBSS AP, check the embedded BSSID through FCS. Until the previous point in time, it cannot be determined whether the WF is transmitted from the OBSS AP. The UE allocates the WUR ID in a direction that reduces the situation in which the same WID/GID/TXID is allocated as much as possible since it consumes more power in the process of detecting and receiving frames and performing FCS calculations than when maintaining the channel in a receiveable state It is important.

In the case of TXID, it identifies the AP of the corresponding WUR network. According to an embodiment of the present invention, when the AP selects the value of the TXID, it is possible to select an arbitrary value among 12 bits. Alternatively, the 12bit LSB or MSB of the compressed BSSID obtained by calculating the BSSID of the AP by 32bit CRC can be used as the TXID. If the AP operates multiple BSSIDs, the TXID is generated using the transmitted BSSID. Alternatively, 12 bits of a specific part of the own BSSID can be used as TXID in another way. Specifically, 12 bits of a specific site may be 12 bits from MSB or 12 bits from LSB. As another method, the BSSID can be divided into 12-bit units and then hashed. For example, if the BSSID is divided into 12-bit units from MSB, a total of 4 sequences are created. Therefore, the value generated by calculating the XOR of the above four sequences can be used as the TXID. Alternatively, it is possible to hash with a specific combination of two or three of the four sequences.

Nontransmitter ID (NTXID) may take values adjacent to the TXID generated by the above method. For example, when an AP uses k nontransmitted BSSIDs, k adjacent 12-bit values greater than TXID or k adjacent 12-bit values smaller than TXID may be used as NTXIDs.

TXID and NTXID may be used when transmitting WF to a WUR terminal belonging to each BSS, and an all BSS transmitter ID (ATXID) for identifying all terminals of all multiple BSSs may be separately defined. The identifier may also be set to 12 bits adjacent to the TXID and NTXID based on the TXID. For example, it may be set to 12 bits with a value one less than TXID or one greater than TXID. A TXID, NTXID, and ATXID have adjacent values, but each preset order combination may be changed according to implementation.

The remaining ID spaces other than the adjacent TXID-related identifiers may be used for WID and GID allocation. When the WID is allocated based on the AID of PCR, the WID may be allocated in the order of AID following the TXID-related identifier. In the case of operating K-1 nontransmitted BSSIDs, AID 0 to AID k-1 of PCR are allocated to identify all terminals corresponding to transmitted and nontransitted BSSIDs, respectively, and are used to identify development terminals from AID k. When k-1 consecutive values from TXID are allocated to NTXID, TXID+k may be allocated as the WID of the terminal corresponding to AID k. If the ATXID is allocated to a value larger than the TXID, the WID allocation may increase by 1.

If the BSS to which a specific WUR terminal belongs is physically operated from the same AP but does not belong to the multiple BSSID set operation, the terminal cannot obtain the transmitted BSSID value that can derive the transmitter ID through the Beacon or Probe Response frame. I can. In this case, the AP may perform a separate WUR operation for the corresponding BSS and operate independently, but there is no technical benefit of operating multiple WUR services, and a separate WUR Beacon frame must be transmitted for each WUR service. Because it can be inefficient. In addition, when the WUR operation channel is different from the WLAN operation channel, the efficiency may be degraded due to frequent channel changes, so it may be effective to integrate the WUR service for the BSS with the existing WUR service. In this case, the AP may selectively notify information for obtaining the transmitter ID through the WUR Mode element. Also, when the AP recognizes that there is an AP using a BSSID that has the same transmitter ID around it, the information may be used to change its own transmitter ID. As mentioned in FIG. 10, the information may directly indicate transmitter ID information or BSSID information. When BSSID information is obtained, it is possible to derive transmitter ID information through CRC operation or the like. A terminal that has obtained the transmitter ID information must obtain nontransmitter ID information to be used by itself by subtracting or adding the value indicated by the Nontransmitter ID Index field from the transmitter ID.

WID allocation can be performed in a random manner as well as an AID-based allocation method. In this case, the WID should be allocated so that it does not overlap with the continuous TXID-related value range and the continuous GID space.

12 shows the format of a WUR PPDU (PCLP Protocol Data Unit) according to an embodiment of the present invention.

The WUR PPDU transmitted by the AP to the WURx of the terminal operating in the WUR mode can be roughly divided into OFDM Part and OOK Part. The OFDM Part is a part inserted for coexistence with Legacy STAs existing in the same BSS as the WUR STA. The OFDM part may not be received by the WURx of the WUR STA, and may be received by the existing 802.11 TR. The OFDM Part uses L-Preamble, which is used in the existing 802.11 standard. The L-Preamble consists of three parts: L-STF, L-LTF, and L-SIG, and using this, legacy STAs estimate the length of the PPDU, and assume that 802.11 PPDUs exist during the time. It is possible to protect the OOK part transmitted afterwards. Additionally, one OFDM symbol may be added after the L-SIG in order to prevent a false detection problem of the legacy terminal (BPSK Mark).

OOK Part can be received by WURx of WUR STA, and it is largely divided into WUR-Sync and WUR-Data parts. In WUR SYNC, a predefined sequence based on modulation such as OOK (On-Off Keying) is transmitted. Through the above sequence, the terminal operating in the WUR mode can check whether the signal being received is a WUR PPDU, and additionally, whether the WUR Frame of the WUR PPDU being received is High Data-Rate (HDR) or Low Data-Rate (LDR). You can judge whether or not. When the PHY layer of the WUR STA detects WUR-Sync and acquires data rate information, the PHY transmits a PHY-RXSTART.indication primitive indicating that the PPDU has been received to the MAC layer. At this time, RXVECTOR included in PHY-RXSTART.indication may include FORMAT information indicating that the received PPDU is a WUR PPDU, and whether the received PPDU is HDR/LDR through WUR-DATARATE.indication information may be notified to the MAC. .

In the WUR-Data part, the data bitstream transmitted by the AP is transmitted in the form of an OOK waveform to which Manchester coding is applied. Information bits obtained by decoding the Manchester coded waveform are included in the PHY-Data.indication primitive in octet units and delivered to the MAC. The PHY that has finished receiving the WUR PPDU may notify the MAC that it has finished receiving the WUR PPDU by transmitting PHY-RXEND.indication. In the case of the WUR PPDU, since the PPDU length information is not inserted in the WUR-Sync, in the case of a terminal implemented such that L-SIG cannot be received, the end point of the PPDU cannot be known. In this case, the PHY may recognize that the WUR PPDU is terminated when the energy sensed in the channel receiving the WUR PPDU rapidly decreases. WUR-Data includes a WUR frame that can be interpreted by the MAC layer. A detailed configuration of the WUR frame will be described with reference to the following drawings. The MAC interpreting the WUR frame can recognize the end point of the WUR frame through the Frame Contorl part. Therefore, when the MAC, which has received all data up to the length indicated by Frame Control, does not receive PHY-RXEND.indication from the PHY, the PHY does not recognize the end of the PPDU due to the energy of signals transmitted from neighboring terminals. It can be judged as. Therefore, the MAC that has not received PHY-RXEND.indication from the time when it is recognized that PHY-RXEND.indication is to be delivered and the time when a preset time elapses from that time transmits the PHY-CCARESET.request primitive to the PHY to receive PPDU. You can make it stop.

The MAC receiving the WUR-Data from the PHY can check the data in real time while reconfiguring the data transmitted in octet units according to the WUR frame format. If the interpreted field indicates that the WUR frame is not intended for itself, the MAC may immediately stop receiving the corresponding WUR frame.

In the existing wireless LAN, when the terminal detects a signal considered to be a wireless LAN frame, decoding of channel coding after receiving the signal to the end of the frame for all frames except for the case where there is an error in the preamble of the received packet. After transmitting the bit stream to the MAC layer, FCS check and information extraction are performed. The reason is that the frame itself is encoded based on the convolution code, so decoding cannot be performed until the entire frame is received. Also, even if it is not a frame transmitted to itself, if it is a frame without errors, This is because additional operations such as NAV setting must be performed based on BSS information and Duration information.

However, in the case of the WUR PPDU, since only the Manchester code and the Repetition code can be applied if the Binary Convolutional Code is not performed, information defined according to the frame format can be sequentially recognized by the UE even if the entire frame is not received. In addition, since a terminal operating using WURx does not need to consider the transmission time of other terminals in a channel situation, it is not necessary to perform an NAV-like operation. Therefore, it is unnecessary to determine the validity of information through FCS check for all received PPDUs, and it is possible to determine the validity of information through FCS check only for PPDUs that are delivered to or contain information that they require. . As a result, when it is determined that the terminal receiving the WUR PPDU is not the terminal it should receive during reception, it is possible to reduce power consumption by stopping the reception of the PPDU in the middle at that time. The above operation is performed from the MAC, and although the MAC determines to stop receiving the PPDU, the PHY may continue to receive the reception operation. If the PHY continues to receive unnecessary WUR PPDUs, it consumes more power than the standby state, and if the received PPDU was a signal received from an external AP, the WUR transmitted by the combined AP transmitted before the end of the corresponding PPDU There may be a problem in that PPDU reception cannot be performed. Therefore, when the MAC decides to stop receiving the PPDU, it is important to stop the PHY reception operation as soon as possible. As an operation to stop the PHY from receiving the PPDU, the MAC may deliver the PHY-CCARESET.request primitive to the PHY. Upon receiving this, the PHY immediately stops receiving and returns to the idle state. That is, when the MAC of the WUR terminal receives PHY-RXSTRAT.indication indicating that it is a WUR PPDU from the PHY, and stops WUR PPDU reception at a time when WUR frame reception is not completed, PHY-CCARESET.request primitive is transmitted. Alternatively, since the MAC is supposed to perform FCS operation after receiving all the data from the PHY, AC received PHY-RXSTRAT.indication indicating that it is a WUR PPDU from the PHY, and the WUR PPDU reception is stopped at the point before FCS operation is performed. In this case, the PHY-CCARESET.request primitive is transmitted.

The WUR terminal may use a PHY layer and a MAC layer in which PCR and WUR are integrated into one due to the implementation structure. Therefore, service primitives such as PHY-CCARESET.request can be shared by WUR and PCR. If the PCR is awake and the WURx operates at the same time, the PHY-CCARESET.request generated in the WUR frame processing affects the PCR frame reception, so that the reception of the PCR frame being normally received can be stopped at the same time. The opposite can also occur. Additional conditions can be defined to solve the above problem. Specifically, when the above conditions are met during WUR frame reception, the PHY-CCARESET.request may be transmitted to the PHY only when the PCR is operating in the Doze state. Even if the WUR frame reception interruption condition is met, PHY-CCARESET.request is not transmitted when the PCR operates in an awake state. The above conditions may be applied in the same manner as PHY-CCARESET.request transmitted after completion of the frame reception described above.

Likewise, when the PCR is in the awake state, the PHY-RXEND.indication may not be transmitted to the MAC even if the WURx recognizes that the energy decreases sharply after receiving the PPDU. Alternatively, even in a situation in which the PHY-RXEND.indication is not delivered at the expected time point after the MAC finishes receiving the WUR frame, the PHY-CCARESET.request may not be transmitted when the UE is in awake state.

As another method to solve the above problem, a separate primitive for WUR can be defined. For example, PHY-CCARESET.request may be newly defined as PHY-WURCCARESET.request and PHY-RXEND.indication as PHY.WURRXEND.indication as a primitive corresponding only to an operation related to WUR reception. In this case, it is possible to transmit a primitive according to a preset condition regardless of the PCR state.

13 illustrates a specific WF format according to an embodiment of the present invention.

A detailed format of the WUR frame will be described with reference to this drawing.

First, type information indicating the type of the transmitted WF may be inserted in the Frame Control part. The type information may indicate whether the corresponding WF is a WUR Beacon, a WUR Wake-Up frame (WUF) requesting a wake-up of the terminal, a WUR Discovery frame for BSS discovery using WUR, or a Vendor Specific frame.

The following part is a protected field indicating whether the WF is a frame protected by applying additional encryption. When receiving the WF with the above field activated, the Message Integrity value is inserted into the FCS instead of the CRC, and the frame is processed only when integrity is verified after performing the MIC operation using the encryption key previously exchanged in the PCR. If not, it should be discarded.

As a subsequent part, when the corresponding WF is WUF, a Length Present indicator indicating whether the frame body is a fixed length (FL) WUF or a frame body is a variable length (VL) WUF may be inserted.

The following part indicates length information according to whether the WF is FL/VL or Length/Misc. Part. If the WF is fixed, since the frame body part of the corresponding WF may not exist, there is no need to indicate Length information, and a WF of a predefined fixed length is transmitted. If the WF type indicates variable length, the frame body part can exist with a variable length. Therefore, it serves to indicate Length information in order to deliver information on the corresponding length. If 3-bit length information is used, frame body (FB) length information of 2-16 octet can be indicated in units of 2 octet. In another implementation, the Length field does not indicate the actual bit length, and length information may be indicated in the form of how many additional information is transmitted on a specific unit basis. For example, in the case of the type of VL WUF, additional WID and Group ID may be listed in the Frame Body, and information on the number of corresponding IDs may be transmitted in the Length part. The protected, Length present, Length/Misc. The order of the fields can be changed depending on the implementation.

In the following ID field, the inserted identifier may vary according to the target and purpose of the WF transmitted by the AP. When the AP transmits the WUR Beacon, the ID field must include a Transmit ID (TXID) that is an identifier of the AP. In addition, when transmitting Broadcast WUF, TXID must be included. In the case of transmitting the WUF for inducing wake-up of a plurality of terminals in the FL WUF, the GID is inserted and transmitted in the ID field. In the case of transmitting the WUF for inducing the wake-up of one terminal, the WID in the ID field Insert and transmit. Setting of the ID field value in the VL WUF will be described in another embodiment.

The following field is a Type Dependent Control field that inserts various additional information for each frame type. The field can be divided into a Counter field and a Sequence Number field. If the transmitted WF is in a specific embodiment, BSS update counter information is inserted in the Counter field to inform whether PCR Beacon reception is required, and partial TSF timer information is inserted in the Sequence Number field to maintain synchronization with the AP. .

If the transmitted WF is a protected WUF, the field configuration may be changed depending on whether the method for detecting a Replay attack is a common IPN method. If the common IPN is not used, 4 bits and 8 bits of the PPN composed of a specific 12 bits of the TSF are inserted into the Counter field and the Sequence Number field, respectively. If a common IPN is used, the Counter field is reserved, and a specific 8 bits of the TSF are inserted into the Sequence Number field.

The following fields are Frame Body fields used in VL WF. A description of the field is described in another embodiment.

The FCS field exists after the frame body. WF is vulnerable to security because the AP's ID is not transmitted and encryption may not be performed, and an attack that consumes power by inducing wake-up of terminals by simply copying and retransmitting the WF received by an external terminal is performed. can do. In order to solve the above problem, the AP may insert a part of its own BSSID information by inserting a virtual Embedded BSSID field when configuring the WF. The Embedded BSSID field may be located after the TD Control field when the Frame Body field does not exist, and after the Frame Body field when the Frame Body field is present. The AP configures the FCS field by performing CRC calculation including the Embedded BSSID field, but when transmitting the actual WF, the Embedded BSSID field can be removed and transmitted. Therefore, the terminal receiving the WF must insert the Embedded BSSID information previously negotiated with the AP after the Address field when calculating the FCS. Through the above operation, the UE can check whether there is an error in the frame during the FCS calculation process and whether it is a WF transmitted from its AP.

If the BSS to which the WUR terminal belongs belongs to the BSS related to the nontransmitted BSSID of the multiple BSSID set, the terminal must generate a compressed BSSID based on the transmitted BSSID used to generate the transmitter ID and perform the embedded BSSID value calculation.

If the terminal operates from the same AP but belongs to a BSS that does not belong to the multiple BSSID set, the embedded BSSID value calculation must be performed by generating a compressed BSSID based on the BSSID information received through the WUR Mode element, not the BSSID of the corresponding BSS. do.

Even if the AP changes the transmitter ID through the WUR mode element, the terminal must maintain and use the compressed BSSID and embedded BSSID values generated by the same process.

While the WUR terminal receives the WF in the same order as described above, if the WF is a format that the terminal does not support, it becomes apparent that the terminal is not called, or if it is suspected that the WF is transmitted from a rogue terminal, the MAC The layer may immediately stop processing, and in order to enable the PHY layer of the UE to immediately stop the reception operation, the MAC layer of the UE may transmit PHY.CCARESET.request to the PHY layer.

For example, 1) When any one of the Type, Protected, and Length present fields is set to an unsupported value, 2) when the ID field indicates an identifier that does not include the corresponding terminal, 3) In the case of protected WF, included in the TD control If the IPN value calculated through the partial TSF related information is less than or equal to the Replay Counter value maintained by the UE internally, processing may be stopped and PHY.CCARESET.request may be delivered to the PHY layer.

14 shows a specific format of a VL WUF according to an embodiment of the present invention.

As another method in which the AP calls multiple terminals at the same time, a VL WUF may be configured to insert a plurality of STA Info fields into a frame body, and a WUR identifier may be inserted into each STA Info field for transmission. In this case, the Length Present field is activated, and the Length field indicates a length value according to the number of STA Info fields.

In this case, the ID field may serve to limit identifiers that may be included in the STA Info field. For example, as described in FIG. 11, when one of TXID/NTXID/ATXID is set as an ID value, the AP may insert an identifier of a terminal belonging to the BSS corresponding to the ID into the STA Info field. Accordingly, since WUR terminals that do not belong to the BSS can stop receiving, it is possible to reduce the number of terminals that process a long VL WUF.

As another method, a specific Group ID may be inserted into the ID field, and only some WIDs of the terminals assigned the GID may be inserted into the STA Info field. In this case, since the number of terminals processing VL WUF is limited to terminals allocated with the GID, the number of terminals processing VL WUF can be further reduced.

If the TXID-related identifier is not allowed in the VL WUF, the TGID/NTGID/ATGID values described in FIG. 12 may be used to play the same role.

As long as the ID field includes an identifier identifying the BSS, the STA Info field may include a GID other than the GID identifying the BSS. In this case, the AP can simultaneously call multiple groups belonging to the BSS specified by the ID field, and it is also possible to simultaneously call multiple groups and multiple individual terminals.

After processing the frame body, the terminal does not process the FCS field and immediately stops receiving the PHY-CCA reset in the PHY layer when the identifier assigned to it is not included in the last STA Info field of the frame body length indicated by the Length field. Can deliver .request.

As a method for obtaining an additional power saving effect while the terminal processes the frame body, a plurality of STA Info fields may be arranged in the order of sizes of identifiers inserted into the field. For example, when the identifiers are arranged in a small order, if a larger WID value is first checked before receiving the WID assigned to it, PHY-CCARESET.request can be delivered to the PHY layer to stop processing and stop receiving immediately. If GID allocation is allowed in the STA Info field, if an identifier larger than the largest value among the WID and GIDs assigned to it is found in the STA Info field, the PHY layer immediately stops processing and stops reception. CCARESET.request can be delivered. At this time, PHY-CCARESET.request may not be transmitted when the PCR is in an awake state as described in the previous figure.

15 illustrates a format of a WUR Discovery frame according to an embodiment of the present invention.

The WUR frame may be used for the purpose of finding a new AP with low power consumption when the terminal roams to another AP or when the connection with the existing AP is disconnected.

This operation is referred to as WUR Scanning, and for this, the AP may transmit a WUR discovery frame to a WUR preset channel or at a preset period in a partial channel thereof. The AP transmits the WUR Discovery frame every preset period, but when the transmission period of (PCR) Beacon and WUR Beacon overlaps, 1) (PCR) Beacon, 2) WUR Discovery after transmitting at the priority of WUR Beacon Frame transmission must be performed. In addition, if the WUR Discovery channel is different from the WUR Beacon channel that transmits the WUR Beacon, the channel is moved every preset period, but only when the above time has elapsed in consideration of the NAVSyncDelay in the moved channel, or when NAV synchronization is performed before that, WUR Discovery frame should be transmitted. In addition, the AP transmits its own WUR Discovery frame and the WUR Discovery frame so that the terminals not currently operating in WUR Mode can perform WUR scanning for the AP more efficiently when WUR Scanning is performed in the future. The channel information to be transmitted may be transmitted by including a Beacon and a probe response frame transmitted based on OFDM.

The UE can perform WUR Scanning when it is not the duty cycle on duration, and the UE performing WUR Scanning receives the WUR Discovery frame transmitted by the neighboring AP while cycling through a preset channel and sends the information to the MAC Layer Management Entity ( MLME) can be delivered to the Station Management Entity (SME) to determine whether to access.

The WUR Discovery frame is indicated by a separate Type field value, and since the Frame Body field exists, the Length Present field is activated. The ID field contains the transmitter ID of the AP transmitting the WUR Discovery frame. Also, in the Type Dependent Control field, 12 bits that are not used as transmitter ID among 12 bits of MSB or LSB of the compressed BSSID of the AP are selected and inserted. In the frame body, a compressed SSID obtained by reducing the SSID of the BSS operated by the AP to 16 bits is inserted, and additionally, operation channel information of the BSS is inserted. Since the WUR Discovery field is a frame for giving BSS information to an arbitrary terminal, embedded BSSID information for security is not inserted.

Even if the AP operates multiple BSSID sets, the ID field and the TD control field must use compressed BSSID information generated based on the transmitted BSSID. However, compressed SSID information may be included in abbreviated SSID information associated with nontransmitted BSSID included in multiple BSSID sets.

As described in the previous figure, the terminal operating in the WUR mode can terminate the reception early if it is not the intended WUR frame, but the SME determines the need for the information contained in the WUR discovery frame. In this case, the information must be delivered to the SME after checking the FCS without stopping reception. Specifically, when the UE performing WUR Scanning receives PHY-RXSTRAT.indication indicating that the MAC is a WUR PPDU from the PHY, and the Type indicates WUR Discovery, the UE performs a reception operation even if the ID field is not a transmitter ID recognized by itself. Must persist. On the other hand, a terminal that does not implement the WUR Discovery function can stop receiving the WUR Discovery frame after checking the Type field according to the existing conditions, and if a terminal that implements the WUR Discovery function is not performing WUR Scanning, check the Type field and then WUR. A condition that the discovery frame can be stopped may be added. Even if the UE is not performing WUR Scanning under other conditions, the WUR Discovery frame may be helpful in obtaining information on the neighboring network, and thus the condition that it is excluded from all WUR PPDU reception interruption conditions may be applied. However, the exception condition may be applied only when the MLME-WURDISCOVERY.indication, which transmits information obtained from WUR Scanning by the MLME of the UE to the SME, is implemented.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be construed that the embodiments described above are illustrative in all respects and are not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: station
200: access point

Claims (1)

Methods, devices and systems for wireless LAN.

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