[go: up one dir, main page]

WO2018128293A1 - Procédé de transmission ou de réception d'un paquet de radio de réveil dans un système lan sans fil et appareil correspondant - Google Patents

Procédé de transmission ou de réception d'un paquet de radio de réveil dans un système lan sans fil et appareil correspondant Download PDF

Info

Publication number
WO2018128293A1
WO2018128293A1 PCT/KR2017/014533 KR2017014533W WO2018128293A1 WO 2018128293 A1 WO2018128293 A1 WO 2018128293A1 KR 2017014533 W KR2017014533 W KR 2017014533W WO 2018128293 A1 WO2018128293 A1 WO 2018128293A1
Authority
WO
WIPO (PCT)
Prior art keywords
wur
subband
sta
mhz
identifier
Prior art date
Application number
PCT/KR2017/014533
Other languages
English (en)
Korean (ko)
Inventor
윤선웅
김정기
박은성
임동국
최진수
Original Assignee
엘지전자 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
Publication of WO2018128293A1 publication Critical patent/WO2018128293A1/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/02—Power saving arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates to a wireless LAN system, and more particularly, to a method and apparatus for transmitting or receiving a WUR packet through a wake up radio (WUR) to wake up a primary connectivity radio (PCR).
  • WUR wake up radio
  • PCR primary connectivity radio
  • IEEE 802.11a and b are described in 2.4. Using unlicensed band at GHz or 5 GHz, IEEE 802.11b provides a transmission rate of 11 Mbps and IEEE 802.11a provides a transmission rate of 54 Mbps.
  • IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps.
  • IEEE 802.11n applies multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps for four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in this case providing a transmission rate of 600 Mbps.
  • the WLAN standard uses a maximum of 160MHz bandwidth, supports eight spatial streams, and supports IEEE 802.11ax standard through an IEEE 802.11ac standard supporting a speed of up to 1Gbit / s.
  • An object of the present invention is to provide a method and apparatus for transmitting or receiving a WUR packet more accurately and efficiently to multiple users.
  • the present invention is not limited to the above-described technical problem and other technical problems can be inferred from the embodiments of the present invention.
  • An access point (AP) for transmitting a wake up radio (WUR) packet for achieving the above-described technical problem, at least among the plurality of WUR subbands included in the PCR (primary connectivity radio) band
  • a processor for selecting one;
  • a transmitter for transmitting, on the selected at least one WUR subband, a WUR packet to wake up a plurality of stations (STAs) operating in a WUR mode under control of the processor.
  • the selection may be performed by considering at least one of an STA identifier assigned to each of the plurality of STAs and an identifier of a basic service set (BSS) operated by the AP before entering the WUR mode.
  • BSS basic service set
  • a method for receiving a WUR packet from a station in a WLAN system is included in a primary connectivity radio (PCR) band. Selecting at least one of the plurality of WUR subbands; And receiving a WUR packet on the selected at least one WUR subband, wherein the selection of the at least one WUR subband comprises: a STA identifier assigned to the STA and the STA prior to entering the WUR mode; It may be performed in consideration of at least one of the identifiers of the BSS (basic service set) to which it belongs.
  • BSS basic service set
  • the selection of the at least one WUR subband may be performed by further considering the number of the plurality of WUR subbands included in the PCR band.
  • the selection of the at least one WUR subband may be performed through a Modulo M operation on the STA identifier or the identifier of the BSS, and M may be the number of the plurality of WUR subbands included in the PCR band.
  • the selection of the at least one WUR subband may be performed by reusing the most significant 2-bit or the least significant 2-bit of the identifier of the BSS as a WUR subband index.
  • the WUR packet may be transmitted for the plurality of STAs in a hybrid manner of parallel transmission in the frequency domain and cascade transmission in the time domain.
  • the bandwidth of the PCR band corresponds to 20 MHz
  • the bandwidth of each of the plurality of subbands may correspond to 4 MHz, 5 MHz, 8 MHz or 10 MHz.
  • At least one null subcarrier may be set between the plurality of subbands, and at least one guard subcarrier may be set at both ends of the PCR band.
  • the identifier of the STA may be an association identifier (AID) assigned through the association procedure, and the identifier of the BSS may be a BSS color or a BSSID.
  • AID association identifier
  • WUR subbands for the corresponding WUR packet transmission are STA identifiers and / or without separate signaling for WUR subband allocation.
  • radio resources for WUR packet transmission may be used more efficiently by being determined through a BSS identifier.
  • FIG. 1 is a diagram illustrating an example of a configuration of a WLAN system.
  • FIG. 2 is a diagram illustrating another example of a configuration of a WLAN system.
  • FIG. 3 is a diagram illustrating a general link setup process.
  • FIG. 4 is a diagram for describing a backoff process.
  • 5 is a diagram for explaining hidden nodes and exposed nodes.
  • FIG. 6 is a diagram for explaining an RTS and a CTS.
  • 7 to 9 are diagrams for explaining the operation of the STA receiving the TIM.
  • FIG. 10 is a diagram for explaining an example of a frame structure used in an IEEE 802.11 system.
  • FIG. 11 is a diagram illustrating a WUR receiver usable in a WLAN system (e.g., 802.11).
  • FIG. 13 shows an example of a WUR packet.
  • FIG. 14 illustrates a waveform for a WUR packet.
  • FIG. 15 illustrates a WUR packet generated using an OFDM transmitter of a wireless LAN.
  • 16 illustrates the structure of a WUR receiver.
  • 17 shows an example of a four-user case.
  • 21 shows another example of a three-user case.
  • 25 shows another example of a two-user case.
  • 26 shows another example of a two-user case.
  • 31 shows another example of a two-user case.
  • 35 shows an example in which three 4 MHz subbands are configured.
  • FIG. 43 is a flowchart illustrating a method of transmitting a WUR packet according to an embodiment of the present invention.
  • 44 is a diagram for explaining an apparatus according to an embodiment of the present invention.
  • the following description relates to a method and an apparatus therefor for efficiently utilizing a channel having a wide band in a WLAN system.
  • a WLAN system to which the present invention is applied will be described in detail.
  • FIG. 1 is a diagram illustrating an example of a configuration of a WLAN system.
  • the WLAN system includes one or more basic service sets (BSSs).
  • BSS is a set of stations (STAs) that can successfully synchronize and communicate with each other.
  • An STA is a logical entity that includes a medium access control (MAC) and a physical layer interface to a wireless medium.
  • the STA is an access point (AP) and a non-AP STA (Non-AP Station). Include.
  • the portable terminal operated by the user among the STAs is a non-AP STA, and when referred to simply as an STA, it may also refer to a non-AP STA.
  • a non-AP STA is a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal, or a mobile subscriber. It may also be called another name such as a mobile subscriber unit.
  • the AP is an entity that provides an associated station (STA) coupled to the AP to access a distribution system (DS) through a wireless medium.
  • STA station
  • DS distribution system
  • the AP may be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.
  • BS base station
  • BTS base transceiver system
  • BSS can be divided into infrastructure BSS and Independent BSS (IBSS).
  • IBSS Independent BSS
  • the BBS shown in FIG. 1 is an IBSS.
  • the IBSS means a BSS that does not include an AP. Since the IBSS does not include an AP, access to the DS is not allowed, thereby forming a self-contained network.
  • FIG. 2 is a diagram illustrating another example of a configuration of a WLAN system.
  • the BSS shown in FIG. 2 is an infrastructure BSS.
  • Infrastructure BSS includes one or more STAs and APs.
  • communication between non-AP STAs is performed via an AP.
  • AP access point
  • a plurality of infrastructure BSSs may be interconnected through a DS.
  • a plurality of BSSs connected through a DS is called an extended service set (ESS).
  • STAs included in the ESS may communicate with each other, and a non-AP STA may move from one BSS to another BSS while seamlessly communicating within the same ESS.
  • the DS is a mechanism for connecting a plurality of APs.
  • the DS is not necessarily a network, and there is no limitation on the form if it can provide a predetermined distribution service.
  • the DS may be a wireless network such as a mesh network or a physical structure that connects APs to each other.
  • the operation of the STA operating in the WLAN system may be described in terms of a layer structure.
  • the hierarchy may be implemented by a processor.
  • the STA may have a plurality of hierarchical structures.
  • the hierarchical structure covered by the 802.11 standard document is mainly the MAC sublayer and physical (PHY) layer on the DLL (Data Link Layer).
  • the PHY may include a Physical Layer Convergence Procedure (PLCP) entity, a Physical Medium Dependent (PMD) entity, and the like.
  • PLCP Physical Layer Convergence Procedure
  • PMD Physical Medium Dependent
  • the MAC sublayer and PHY conceptually contain management entities called MAC sublayer management entities (MLMEs) and physical layer management entities (PLMEs), respectively.These entities provide a layer management service interface on which layer management functions operate. .
  • SME Station Management Entity
  • An SME is a layer-independent entity that can appear to be in a separate management plane or appear to be off to the side. While the exact features of the SME are not described in detail in this document, they generally do not include the ability to collect layer-dependent states from various Layer Management Entities (LMEs), and to set similar values for layer-specific parameters. You may seem to be in charge. SMEs can generally perform these functions on behalf of general system management entities and implement standard management protocols.
  • LMEs Layer Management Entities
  • the aforementioned entities interact in a variety of ways.
  • entities can interact by exchanging GET / SET primitives.
  • a primitive means a set of elements or parameters related to a particular purpose.
  • the XX-GET.request primitive is used to request the value of a given MIB attribute (management information based attribute information).
  • the XX-GET.confirm primitive is used to return the appropriate MIB attribute information value if the Status is "Success", otherwise it is used to return an error indication in the Status field.
  • the XX-SET.request primitive is used to request that the indicated MIB attribute be set to a given value. If the MIB attribute means a specific operation, this is to request that the operation be performed.
  • the XX-SET.confirm primitive confirms that the indicated MIB attribute is set to the requested value when status is "success", otherwise it is used to return an error condition in the status field. If the MIB attribute means a specific operation, this confirms that the operation has been performed.
  • the MLME and SME may exchange various MLME_GET / SET primitives through a MLME_SAP (Service Access Point).
  • various PLME_GET / SET primitives may be exchanged between PLME and SME through PLME_SAP and may be exchanged between MLME and PLME through MLME-PLME_SAP.
  • FIG. 3 is a diagram illustrating a general link setup process.
  • an STA In order for an STA to set up a link and transmit / receive data with respect to a network, an STA first discovers the network, performs authentication, establishes an association, and authenticates for security. It must go through the back.
  • the link setup process may also be referred to as session initiation process and session setup process.
  • a process of discovery, authentication, association, and security establishment of a link setup process may be collectively referred to as association process.
  • 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 must find a network that can participate. The STA must identify a compatible network before joining the wireless network. A network identification process existing in a specific area is called scanning.
  • the STA performing scanning transmits a probe request frame and waits for a response to discover which AP exists in the vicinity while moving channels.
  • the responder transmits a probe response frame to the STA that transmits the probe request frame in response to the probe request frame.
  • the responder may be an STA that last transmitted a beacon frame in the BSS of the channel being scanned.
  • the AP transmits a beacon frame, so the AP becomes a responder.
  • the responder is not constant.
  • an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 stores the BSS-related information included in the received probe response frame and stores the next channel (eg, number 2).
  • Channel to perform scanning (i.e., probe request / response transmission and reception on channel 2) in the same manner.
  • the scanning operation may be performed by a passive scanning method.
  • passive scanning the STA performing scanning waits for a beacon frame while moving channels.
  • the beacon frame is one of management frames in IEEE 802.11.
  • the beacon frame is notified of the existence of a wireless network and is periodically transmitted to allow the STA performing scanning to find the wireless network and participate in the wireless network.
  • the AP periodically transmits a beacon frame
  • the IBSS STAs in the IBSS rotate and transmit a beacon frame.
  • the STA that performs the scanning receives the beacon frame, the STA stores the information on the BSS included in the beacon frame and records beacon frame information in each channel while moving to another channel.
  • the STA may store BSS related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.
  • active scanning has the advantage of less delay and power consumption than passive scanning.
  • step S520 After the STA discovers the network, an authentication process may be performed in step S520.
  • This authentication process may be referred to as a first authentication process in order to clearly distinguish from the security setup operation of step S540 described later.
  • the authentication process includes a process in which the STA transmits an authentication request frame to the AP, and in response thereto, 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, and a finite cyclic group. Group) and the like. 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 further include additional information.
  • the STA may send an authentication request frame to the AP.
  • the AP may determine whether to allow authentication for the corresponding STA based on the information included in the received authentication request frame.
  • the AP may provide a result of the authentication process to the STA through an authentication response frame.
  • the association process includes a process in which the STA transmits an association request frame to the AP, and in response thereto, the AP transmits an association response frame to the STA.
  • the association request frame may include information related to various capabilities, beacon listening interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain. Information about supported operating classes, TIM Broadcast Indication Map Broadcast request, interworking service capability, and the like.
  • an association response frame may include information related to various capabilities, status codes, association IDs (AIDs), support rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicators (RCPI), Received Signal to Noise Information, such as an indicator, a mobility domain, a timeout interval (association comeback time), an overlapping BSS scan parameter, a TIM broadcast response, and a QoS map.
  • AIDs association IDs
  • EDCA Enhanced Distributed Channel Access
  • RCPI Received Channel Power Indicators
  • Received Signal to Noise Information such as an indicator, a mobility domain, a timeout interval (association comeback time), an overlapping BSS scan parameter, a TIM broadcast response, and a QoS map.
  • a security setup process may be performed at step S540.
  • the security setup process of step S540 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response.
  • the authentication process of step S520 is called a first authentication process, and the security setup process of step S540 is performed. It may also be referred to simply as the authentication process.
  • RSNA Robust Security Network Association
  • the security setup process of step S540 may include, for example, performing a private key setup through 4-way handshaking through an Extensible Authentication Protocol over LAN (EAPOL) frame. .
  • the security setup process may be performed according to a security scheme not defined in the IEEE 802.11 standard.
  • a basic access mechanism of MAC is a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism.
  • the CSMA / CA mechanism is also called the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC. It basically employs a "listen before talk" access mechanism.
  • the AP and / or STA may sense a radio channel or medium during a predetermined time period (e.g., during a DCF Inter-Frame Space (DIFS), before starting transmission.
  • DIFS DCF Inter-Frame Space
  • a delay period for example, a random backoff period
  • HCF hybrid coordination function
  • the PCF refers to a polling-based synchronous access scheme in which polling is performed periodically so that all receiving APs and / or STAs can receive data frames.
  • the HCF has an Enhanced Distributed Channel Access (EDCA) and an HCF Controlled Channel Access (HCCA).
  • EDCA is a competition based approach for providers to provide data frames to multiple users, and HCCA uses a non-competition based channel access scheme using a polling mechanism.
  • the HCF includes a media access mechanism for improving the quality of service (QoS) of the WLAN, and can transmit QoS data in both a contention period (CP) and a contention free period (CFP).
  • QoS quality of service
  • FIG. 4 is a diagram for describing a backoff process.
  • the random backoff count has a packet number value and may be determined as one of values ranging from 0 to CW.
  • CW is a contention window parameter value.
  • the CW parameter is given CWmin as an initial value, but may take a double value in case of transmission failure (eg, when an ACK for a transmitted frame is not received).
  • the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits; if the medium is idle, it resumes the remaining countdown.
  • the STA3 may confirm that the medium is idle as much as DIFS and transmit the frame immediately. Meanwhile, the remaining STAs monitor and wait for the medium to be busy. In the meantime, data may also be transmitted in each of STA1, STA2, and STA5, and each STA waits for DIFS when the medium is monitored idle, and then counts down the backoff slot according to a random backoff count value selected by the STA. Can be performed. In the example of FIG. 4, STA2 selects the smallest backoff count value, and STA1 selects the largest backoff count value.
  • the remaining backoff time of the STA5 is shorter than the remaining backoff time of the STA1 at the time when the STA2 finishes the backoff count and starts the frame transmission.
  • STA1 and STA5 stop counting for a while and wait for STA2 to occupy the medium.
  • the STA1 and the STA5 resume the stopped backoff count after waiting for DIFS. That is, the frame transmission can be started after counting down the remaining backoff slots by the remaining backoff time. Since the remaining backoff time of the STA5 is shorter than that of the STA1, the STA5 starts frame transmission. Meanwhile, while STA2 occupies the medium, data to be transmitted may also occur in STA4.
  • the STA4 waits for DIFS, performs a countdown according to a random backoff count value selected by the STA4, and starts frame transmission.
  • the remaining backoff time of STA5 coincides with an arbitrary backoff count value of STA4.
  • a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receive an ACK, and thus data transmission fails. In this case, STA4 and STA5 may double the CW value, select a random backoff count value, and perform a countdown.
  • the STA1 waits while the medium is occupied due to transmission of the STA4 and STA5, waits for DIFS when the medium is idle, and starts frame transmission after the remaining backoff time passes.
  • the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which the AP and / or STA directly sense the medium.
  • Virtual carrier sensing is intended to compensate for problems that may occur in media access, such as a hidden node problem.
  • the MAC of the WLAN system may use a network allocation vector (NAV).
  • the NAV is a value in which an AP and / or STA currently using or authorized to use a medium instructs another AP and / or STA how long to remain until the medium becomes available.
  • the value set to NAV corresponds to a period in which the medium is scheduled to be used by the AP and / or STA transmitting the corresponding frame, and the STA receiving the NAV value is prohibited from accessing the medium during the period.
  • the NAV may be set, for example, according to the value of the "duration" field of the MAC header of the frame.
  • 5 is a diagram for explaining hidden nodes and exposed nodes.
  • 5A illustrates an example of a hidden node, in which STA A and STA B are in communication and STA C has information to transmit.
  • STA A may be transmitting information to STA B, it may be determined that the medium is idle when STA C performs carrier sensing before sending data to STA B. This is because transmission of STA A (ie, media occupation) may not be sensed at the location of STA C.
  • STA B since STA B receives the information of STA A and STA C at the same time, a collision occurs.
  • STA A may be referred to as a hidden node of STA C.
  • FIG. 5B is an example of an exposed node
  • STA B is a case in which STA C has information to be transmitted from STA D while transmitting data to STA A.
  • FIG. 5B is an example of an exposed node
  • STA C is a case in which STA C has information to be transmitted from STA D while transmitting data to STA A.
  • FIG. 5B when STA C performs carrier sensing, it may be determined that the medium is occupied by the transmission of STA B. Accordingly, since STA C is sensed as a medium occupancy state even if there is information to be transmitted to STA D, it must wait until the medium becomes idle. However, since STA A is actually outside the transmission range of STA C, transmission from STA C and transmission from STA B may not collide with STA A's point of view, so STA C is unnecessary until STA B stops transmitting. To wait. At this time, STA C may be referred to as an exposed node of STA B.
  • FIG. 6 is a diagram for explaining an RTS and a CTS.
  • a short signaling packet such as a request to send (RTS) and a clear to send (CTS) may be used.
  • RTS request to send
  • CTS clear to send
  • the RTS / CTS between the two STAs may allow the surrounding STA (s) to overhear, allowing the surrounding STA (s) to consider whether to transmit information between the two STAs. For example, when an STA to transmit data transmits an RTS frame to an STA receiving the data, the STA receiving the data may inform the neighboring STAs that they will receive the data by transmitting the CTS frame.
  • FIG. 6A illustrates an example of a method for solving a hidden node problem, and assumes that both STA A and STA C try to transmit data to STA B.
  • FIG. 6A When STA A sends the RTS to STA B, STA B transmits the CTS to both STA A and STA C around it. As a result, STA C waits until data transmission between STA A and STA B is completed, thereby avoiding collision.
  • FIG. 6 (b) illustrates an example of a method for solving an exposed node problem
  • STA C overhears RTS / CTS transmission between STA A and STA B so that STA C may use another STA (eg, STA). It may be determined that no collision will occur even if data is transmitted to D). That is, STA B transmits the RTS to all neighboring STAs, and only STA A having the data to actually transmit the CTS. Since STA C receives only RTS and not STA A's CTS, it can be seen that STA A is out of STC C's carrier sensing.
  • the WLAN system channel sensing must be performed before the STA performs transmission and reception, and always sensing the channel causes continuous power consumption of the STA.
  • the power consumption in the receive state is not significantly different from the power consumption in the transmit state, and maintaining the receive state is also a great burden for the power limited STA (ie, operated by a battery). Therefore, if the STA maintains the reception standby state in order to continuously sense the channel, it inefficiently consumes power without any particular advantage in terms of WLAN throughput.
  • the WLAN system supports a power management (PM) mode of the STA.
  • PM power management
  • the power management mode of the STA is divided into an active mode and a power save (PS) mode.
  • the STA basically operates in the active mode.
  • the STA operating in the active mode maintains an awake state.
  • the awake state is a state in which normal operation such as frame transmission and reception or channel scanning is possible.
  • the STA operating in the PS mode operates by switching between a sleep state (or a doze state) and an awake state.
  • the STA operating in the sleep state operates at the minimum power, and does not perform frame scanning as well as channel scanning.
  • the STA operates in the sleep state for as long as possible, power consumption is reduced, so the STA has an increased operation period. However, it is impossible to operate unconditionally long because frame transmission and reception are impossible in the sleep state. If there is a frame to be transmitted to the AP, the STA operating in the sleep state may transmit the frame by switching to the awake state. On the other hand, when the AP has a frame to transmit to the STA, the STA in the sleep state may not receive it and may not know that there is a frame to receive. Accordingly, the STA may need to switch to the awake state according to a specific period in order to know whether or not the frame to be transmitted to (or, if there is, receive it) exists.
  • the AP may transmit a beacon frame to STAs in the BSS at regular intervals.
  • the beacon frame may include a traffic indication map (TIM) information element.
  • the TIM information element may include information indicating that the AP has buffered traffic for STAs associated with the AP and transmits a frame.
  • the TIM element includes a TIM used to inform unicast frames and a delivery traffic indication map (DTIM) used to inform multicast or broadcast frames.
  • DTIM delivery traffic indication map
  • 7 to 9 are diagrams for explaining in detail the operation of the STA receiving the TIM.
  • the STA may switch from the sleep state to the awake state to receive a beacon frame including the TIM from the AP, interpret the received TIM element, and know that there is buffered traffic to be transmitted to the AP. .
  • the STA may transmit a PS-Poll frame to request an AP to transmit a data frame.
  • the AP may transmit the frame to the STA.
  • the STA may receive a data frame and transmit an acknowledgment (ACK) frame thereto to the AP.
  • the STA may then go back to sleep.
  • ACK acknowledgment
  • the AP may operate according to an immediate response method of transmitting a data frame after a predetermined time (for example, a short inter-frame space (SIFS)) after receiving a PS-Poll frame from an STA. Can be. Meanwhile, when the AP fails to prepare a data frame to be transmitted to the STA during the SIFS time after receiving the PS-Poll frame, the AP may operate according to a deferred response method, which will be described with reference to FIG. 8.
  • a predetermined time for example, a short inter-frame space (SIFS)
  • SIFS short inter-frame space
  • the STA switches from the sleep state to the awake state to receive the TIM from the AP and transmits the PS-Poll frame to the AP through contention as in the example of FIG. 7. If the AP does not prepare a data frame during SIFS even after receiving the PS-Poll frame, the AP may transmit an ACK frame to the STA instead of transmitting the data frame. When the data frame is prepared after transmitting the ACK frame, the AP may transmit the data frame to the STA after performing contention. The STA may transmit an ACK frame indicating that the data frame was successfully received to the AP and go to sleep.
  • STAs may transition from a sleep state to an awake state to receive a beacon frame containing a DTIM element from the AP. STAs may know that a multicast / broadcast frame will be transmitted through the received DTIM.
  • the AP may transmit data (ie, multicast / broadcast frame) immediately after the beacon frame including the DTIM without transmitting and receiving the PS-Poll frame.
  • the STAs may receive data while continuously awake after receiving the beacon frame including the DTIM, and may switch back to the sleep state after the data reception is completed.
  • FIG. 10 is a diagram for explaining an example of a frame structure used in an IEEE 802.11 system.
  • the Physical Layer Protocol Data Unit (PPDU) frame format may include a Short Training Field (STF), a Long Training Field (LTF), a SIG (SIGNAL) field, and a Data field.
  • STF Short Training Field
  • LTF Long Training Field
  • SIGNAL SIGNAL
  • Data field a Data field.
  • the most basic (eg, non-HT) PPDU frame format may include only a legacy-STF (L-STF), a legacy-LTF (L-LTF), a SIG field, and a data field.
  • the STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc.
  • the LTF is a signal for channel estimation, frequency error estimation, and the like.
  • the STF and LTF may be referred to as a PLCP preamble, and the PLCP preamble may be referred to as a signal for synchronization and channel estimation of an OFDM physical layer.
  • the SIG field may include a RATE field and a LENGTH field.
  • the RATE field may include information about modulation and coding rate of data.
  • the LENGTH field may include information about the length of data.
  • 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), a PPDU TAIL bit, and may also include a padding bit if necessary.
  • Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end.
  • the PSDU corresponds to an MPDU (MAC Protocol Data Unit) defined in the MAC layer and may include data generated / used in an upper layer.
  • the PPDU TAIL bit can be used to return the encoder to zero.
  • the padding bit may be used to adjust the length of the data field in a predetermined unit.
  • the MPDU is defined according to various MAC frame formats, and the basic MAC frame is composed of a MAC header, a frame body, and a frame check sequence (FCS).
  • the MAC frame may consist of MPDUs and may be transmitted / received through the PSDU of the data portion 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 the corresponding frame.
  • the duration / ID field included in the MAC header may be set to 16 bits long (e.b., B0 to B15).
  • the content included in the period / ID field may vary depending on the frame type and subtype, whether the content is transmitted during the CFP (contention free period), the QoS capability of the transmitting STA, and the like.
  • the duration / ID field may include the AID of the transmitting STA (e.g., via 14 LSB bits) and the 2 MSB bits may be set to one.
  • the period / ID field may be set to a fixed value (e.g., 32768).
  • the duration / ID field may include a duration value defined for each frame type.
  • Sequence Control, QoS Control, and HT Control subfields of the MAC header refer to the IEEE 802.11 standard document.
  • the frame control field of the MAC header may include Protocol Version, Type, Subtype, To DS, From DS, More Fragment, Retry, Power Management, More Data, Protected Frame, Order subfields.
  • the content of each subfield of the frame control field may refer to an IEEE 802.11 standard document.
  • an STA includes a primary connectivity radio (PCR) (eg, IEEE 802.11a / b / g / n / ac / ax WLAN) and a wake up radio for main wireless communication.
  • PCR primary connectivity radio
  • WUR eg, IEEE 802.11ba
  • PCR is used for data transmission and reception, and may be turned off when there is no data to transmit and receive. As such, when the PCR is turned off, the WURx of the STA may wake up the PCR when there is a packet to receive. Therefore, user data is transmitted and received through PCR.
  • WURx is not used for user data, it can only serve to wake up the PCR transceiver.
  • WURx can be in the form of a simple receiver without a transmitter and is active while PCR is off. It is desirable that the target power consumption of the WURx in the activated state does not exceed 100 microwatts (uW).
  • a simple modulation scheme for example, an on-off keying (OOK) scheme, may be used, and a narrow bandwidth (e.g., 4 MHz, 5 MHz) may be used.
  • the reception range (e.g., distance) that WURx targets may be equivalent to the current 802.11.
  • FIG. 12 is a diagram for explaining the design and operation of a WUR packet.
  • the WUR packet may include a PCR part 1200 and a WUR part 1205.
  • the PCR part 1200 is for coexistence with the legacy WLAN system, and the PCR part may be referred to as a WLAN preamble.
  • the PCR part may be referred to as a WLAN preamble.
  • at least one or more of L-STF, L-LTF, and L-SIG of the legacy WLAN may be included in the PCR part 1200.
  • the 3rd party legacy STA may know that the WUR packet is not intended for the user through the PCR part 1200 of the WUR packet, and that the medium of the PCR is occupied by another STA.
  • WURx does not decode the PCR part of the WUR packet. This is because WURx, which supports narrowband and OOK demodulation, does not support PCR signal reception.
  • At least a part of the WUR part 1205 may be modulated by an on-off keying (OOK) method.
  • the WUR part may include at least one of a WUR preamble, a MAC header (e.g., a recipient address, etc.), a frame body, and a frame check sequence (FCS).
  • OOK modulation may be performed by modifying the OFDM transmitter.
  • WURx 1210 consumes very little power of 100 uW or less as described above and can be implemented with a small and simple OOK demodulator.
  • the WUR packet since the WUR packet needs to be designed to be compatible with the WLAN system, the WUR packet includes a preamble (eg, OFDM) and a new LP-WUR signal waveform (eg, OOK) of legacy WLAN. can do.
  • a preamble eg, OFDM
  • a new LP-WUR signal waveform eg, OOK
  • the WUR packet of FIG. 13 shows an example of a WUR packet.
  • the WUR packet of FIG. 13 includes a PCR part (e.g., legacy WLAN preamble) for coexistence with a legacy STA.
  • a PCR part e.g., legacy WLAN preamble
  • the legacy WLAN preamble may include L-STF, L-LTF, and L-SIG.
  • the WLAN STA e.g., 3rd Party
  • the WLAN STA may detect the start of a WUR packet through the L-STF.
  • the WLAN STA e.g., 3rd Party
  • the L-SIG field may indicate the length of the payload (e.g., OOK modulated) of the WUR packet.
  • the WUR part may include at least one of a WUR preamble, a MAC header, a frame body, and an FCS.
  • the WUR preamble may include, for example, a PN sequence.
  • the MAC header may include the receiver address.
  • the frame body may contain other information needed for wake up.
  • the FCS may include a cyclic redundancy check (CRC).
  • FIG. 14 illustrates the waveform for the WUR packet of FIG. 13.
  • 1 bit may be transmitted per 1 OFDM symbol length (e.g., 4 usec).
  • the data rate of the WUR part may be 250 kbps.
  • FIG. 15 illustrates generation of a WUR packet using an OFDM transmitter of a wireless LAN.
  • a phase shift keying (PSK) -OFDM transmission scheme is used.
  • Generating a WUR packet by adding a separate OOK modulator for OOK modulation has a disadvantage of increasing an implementation cost of a transmitter. Therefore, a method of generating a OOK modulated WUR packet by reusing an OFDM transmitter will be described.
  • bit value 1 is modulated into a symbol (i.e., on) having a power above a threshold
  • bit value 0 is modulated into a symbol (i.e., off) having a power below a threshold.
  • bit value 1 it is also possible to define bit value 1 as power off.
  • OOK modulation scheme As described above, in the OOK modulation scheme, a bit value 1/0 is indicated through on / off of power at a corresponding symbol position.
  • Such a simple OOK modulation / demodulation scheme has an advantage of reducing power consumption and cost for realizing the signal detection / demodulation of the receiver.
  • OOK modulation for turning on / off a signal may be performed by reusing an existing OFDM transmitter.
  • the left graph of FIG. 15 shows the real part and the imaginary part of normalized amplitude during one symbol period (eg, 4 usec) for OOK modulated bit value 1 by reusing the OFDM transmitter of the existing WLAN. (imaginary) shows the part. Since the OOK modulation result for the bit value 0 corresponds to power off, illustration is omitted.
  • the right graph of FIG. 15 shows normalized power spectral density (PSD) in the frequency domain for OOK modulated bit value 1 by reusing an OFDM transmitter of an existing WLAN.
  • PSD power spectral density
  • a center 4 MHz in that band may be used for the WUR.
  • the WUR operates with a 4 MHz bandwidth.
  • a frequency bandwidth of another size may be used.
  • the subcarrier spacing (e.g., subcarrier spacing) is 312.5 kHz, and the bandwidth of the OOK pulse corresponds to 13 subcarriers.
  • CP cyclic prefix
  • the WUR packet may be referred to as a WUR signal, a WUR frame, or a WUR PPDU.
  • the WUR packet may be a packet for broadcast / multicast (e.g., WUR beacon) or a packet for unicast (e.g., a packet for terminating and waking up the WUR mode of a specific WUR STA).
  • the WURx may include an RF / analog front-end, a digital baseband processor, and a simple packet parser. 16 is an exemplary configuration, and the WUR receiver of the present invention is not limited to FIG.
  • a WLAN STA having a WUR receiver will be referred to simply as a WUR STA.
  • the WUR STA may be referred to simply as STA.
  • 1 bit may be represented using a symbol having the same length as that of the existing Wi-Fi (e.g., PCR).
  • An information signal of 3.2 us may be formed by applying a specific sequence to the available WUR subcarriers (e.g., 13 subcarriers) and then performing IFFT.
  • a 3.2 us OFF-signal may be generated by applying zero to all of the corresponding subcarriers (e.g., IFFT coefficients).
  • the cyclic prefix (CP) may be selected by a predetermined length at the end of the 3.2us information signal located immediately after the corresponding CP.
  • the length of the CP may for example be 0.4 us or 0.8 us.
  • the CP length may be set equal to the guard interval (GI) of 11ac.
  • 1-bit information When 1-bit information is '0', it may correspond to a 3.2us OFF signal, and when 1-bit information is '1', it may correspond to a 3.2us On-signal. Conversely, the on / off-signal mapping for each bit value may be reversed.
  • Manchester coding may be used to generate OOK symbols.
  • one-bit information is indicated through two sub information (or two coded bits).
  • two lower information bits '10' i.e., On-Off
  • the 1-bit information '1' passes through Manchester coding
  • two lower information bits '01' i.e., Off-On
  • the on-off order of the lower information bits may be reversed according to an embodiment.
  • one OOK symbol is 3.2 us in the time domain and corresponds to K subcarriers in the frequency domain, but the present invention is not limited thereto.
  • the length of 1 OOK symbol is (i) 1.6 us for the first lower information bit '1' and (ii) It can be divided into 1.6 us for the second lower information bit '0'.
  • a signal corresponding to the first lower information bit '1' is obtained by mapping ⁇ to odd subcarriers among K subcarriers, and mapping 0 to even subcarriers and performing IFFT.
  • IFFT is performed by mapping ⁇ at two subcarrier intervals on the frequency domain
  • a periodic signal of 1.6 us appears twice in the time domain.
  • the first or second signal of the 1.6 us periodic signal repeated twice may be used as the signal corresponding to the first lower information bit '1'.
  • ⁇ may be, for example, 1 / sqrt (ceil (K / 2)) as the power normalization factor.
  • consecutive K subcarriers used to generate a signal corresponding to the first lower information bit '1' of all 64 subcarriers are, for example, [33-floor (K / 2): 33 + ceil (K / 2) -1].
  • the signal corresponding to the second lower information bit '0' may be obtained by mapping 0 to K subcarriers and performing IFFT.
  • consecutive K subcarriers used to generate a signal corresponding to the second lower information bit '0' of the total 64 subcarriers are, for example, [33-floor (K / 2): 33 + ceil (K / 2) -1].
  • the OOK symbol for 1-bit information '1' may be obtained by disposing a signal corresponding to the lower information bit '1' after the signal corresponding to the lower information bit '0'.
  • one symbol length for WUR may be set smaller than 3.2 us.
  • one symbol may be set to information + CP of 1.6us, 0.8us or 0.4us.
  • a time domain signal can be obtained by mapping 0 to K subcarriers and performing IFFT, one of which can be used with a 0.8us length signal.
  • a time domain signal can be obtained by mapping 0 to K subcarriers and performing IFFT, and one 0.4us length signal can be used.
  • the 13-subcarrier corresponds to 4 MHz
  • the 16-subcarrier corresponds to 5 MHz
  • the 26-subcarrier may correspond to 8 MHz.
  • the present invention is not limited thereto and other numbers of subcarriers may be used for WUR packet transmission.
  • 17 shows an example of a four-user case.
  • 16 subcarriers may be used for each user in a 4-user case. There may be interference between users because subcarriers are attached between adjacent users. That is, since there is no guard subcarrier between users, interference may be caused from adjacent bands.
  • 3 * 16-subcarriers out of a total of 64 subcarriers may be selected for WUR packet transmission for 3-user.
  • the 4-subcarrier at the left end and the 3-subcarrier at the right end may be used as guard subcarriers.
  • null subcarrier portions are located.
  • the null subcarrier portions may correspond to a total of 9 subcarriers.
  • the number of subcarriers included in four null subcarrier portions may be [3, 2, 2, 2], [2, 3, 2, 2], [2, 2, 3, 2] or [2], respectively. , 2, 2, 3].
  • the null subcarrier parts may correspond to a total of 9-subcarriers.
  • the number of subcarriers included in the two null subcarrier portions may be [5, 4] or [4, 5], respectively. 19 has an advantage of further reducing interference between users compared to FIG. 18.
  • the left end 6-subcarrier and the right end 5-subcarrier may be used as guard subcarriers.
  • null subcarrier portions are located.
  • the null subcarrier portions may correspond to a total of five subcarriers.
  • the number of subcarriers included in the four null subcarrier portions may be [2, 1, 1, 1], [1, 2, 1, 1], [1, 1, 2, 1] or [1], respectively. , 1, 1, 2].
  • 21 shows another example of a three-user case.
  • the null subcarrier portions may correspond to a total of five subcarriers.
  • the number of subcarriers included in the two null subcarrier portions may be [3, 2] or [2, 3], respectively. 21 has an advantage of further reducing interference between users as compared to FIG. 20.
  • the 22 shows a case without a guard subcarrier.
  • a total of four null subcarrier parts are located.
  • the null subcarrier portions may each correspond to a four-subcarrier.
  • the interference received from other 20 MHz bands may increase.
  • the 4-subcarrier at the left end and the 3-subcarrier at the right end may be used as guard subcarriers.
  • null subcarrier portions are located.
  • the null subcarrier portions may correspond to a total of 25 subcarriers.
  • the number of subcarriers included in the three null subcarrier portions may be [9, 8, 8], [8, 9, 8] or [8, 8, 9], respectively.
  • the null subcarrier portion may correspond to a 25-subcarrier. 24 has an advantage of further reducing interference between users as compared to FIG. 23.
  • 25 shows another example of a two-user case.
  • the left end 6-subcarrier and the right end 5-subcarrier may be used as guard subcarriers.
  • null subcarrier portions may correspond to a total of 21 subcarriers.
  • the number of subcarriers included in three null subcarrier portions may be [7, 7, 7], respectively.
  • 26 shows another example of a two-user case.
  • FIG. 26 a total of one null subcarrier portion is located.
  • the null subcarrier portion may correspond to a 21-subcarrier.
  • FIG. 26 has an advantage of further reducing interference between users as compared to FIG. 25.
  • the null subcarrier parts may correspond to a total of 32 subcarriers.
  • the number of subcarriers included in the three null subcarrier portions may be [11, 11, 10], [11, 10, 11], or [10, 11, 11], respectively.
  • only one group selected from four 16-subcarrier groups for 4-user is used for WUR packet transmission for 1-user, or from three 16-subcarrier groups for 3-user. Only one selected group can be used for WUR packet transmission for 2-user, or only one group selected from two 16-subcarrier groups for 2-user can be used for WUR packet transmission for 1-user. have.
  • each of the null subcarrier portions may correspond to a 24-subcarrier. For example, when a WUR packet is transmitted over 16 subcarriers located in the center of a 20 MHz band, interference from an adjacent 20 MHz band may be minimized.
  • 29 shows an example of a two-user case.
  • 26-subcarriers out of a total of 64 subcarriers may be selected for WUR packet transmission for a 2-user.
  • the 4-subcarrier at the left end and the 3-subcarrier at the right end may be used as guard subcarriers.
  • null subcarrier portions are located.
  • the null subcarrier portions may correspond to a total of five subcarriers.
  • the number of subcarriers included in the three null subcarrier portions is [1, 3, 1], [2, 1, 2], [2, 2, 1] or [1, 2, 2] days, respectively. Can be.
  • interference between users can be reduced more than [2, 1, 2], [2, 2, 1] or [1, 2, 2].
  • the null subcarrier portion may correspond to a 5-subcarrier.
  • FIG. 30 has less interference between users than FIG. 29, interference received from another 20 MHz band may increase.
  • 31 shows another example of a two-user case.
  • the left end 6-subcarrier and the right end 5-subcarrier may be used as guard subcarriers.
  • null subcarrier portion may correspond to 1-subcarrier. Since only one null subcarrier is located between users, interference between users can be relatively large.
  • the 32 shows a case without a guard subcarrier.
  • a total of three null subcarrier parts are located.
  • the null subcarrier parts may correspond to a total of 12 subcarriers.
  • the number of subcarriers included in three null subcarrier portions may be four.
  • only one group selected from two 26-subcarrier groups for two-user may be used for WUR packet transmission for one-user.
  • Each of the null subcarrier portions may correspond to a 19-subcarrier. For example, when a WUR packet is transmitted over 26 subcarriers located in the center of a 20 MHz band, interference from an adjacent 20 MHz band may be minimized.
  • the AP may allocate the WUR subband based on information used by the WUR STAs in the process of BSS association. For example, the AP may allocate the WUR subband to be used by the WUR STA using the BSSID, BSS color and / or AID.
  • the number of subbands included in the 20 MHz band may be variously set.
  • FIG. 17 for a 4-subband case
  • FIG. 18 for a 3-subband case
  • FIG. 23 for a 2-subband case
  • a 1-subband case. 28 may be referred to, the present invention is not limited thereto.
  • the AP may allocate a subband using, for example, a part of BSS color 6-bits (e.g., 2-bits of MSB and MSB-1 bits).
  • a subband may be allocated to each user by using an AID.
  • subbands 1, 2 and 3 The three subbands are referred to as subbands 1, 2 and 3 in order from the left.
  • subband 4 may be allocated.
  • subbands may be allocated via modulo 2 operation on BSS color.
  • the 8 MHz subband may correspond to 26 subcarriers, in which case up to two users may be allocated within 20 MHz.
  • (2-i) 1 subband and 1 user use a subband in which 26 subcarriers are evenly and evenly arranged based on subcarrier 0 (eg, center subcarrier). . In this case, interference from adjacent 20 MHz bands can be minimized.
  • the 4 MHz subband may correspond to a 13-subcarrier.
  • the WUR packet may be transmitted on 13 consecutive subcarriers among 64 subcarriers included in the 20 MHz band.
  • 34 shows an example in which four 4 MHz subbands are configured.
  • 35 shows an example in which three 4 MHz subbands are configured.
  • 36 shows an example in which two 4 MHz subbands are configured.
  • 37 shows an example in which one 4 MHz subband is configured.
  • the WUR subband may be allocated through information used by the WUR STA in the BSS association process.
  • subbands may be allocated using BSSID, BSS color or AID information.
  • (2-ii) 4-subband and 3 users: for example, if (MSB, MSB-1) or (LSB + 1, LSB) (0, 0) of BSS color is 1, and (0, 1) Subband 2, (1, 0), subband 3, and (1, 1), subband 4 may be allocated. Alternatively, subbands may be allocated through modulo 4 operation on BSS color or AID.
  • the AP may determine whether the corresponding STA is capable of WUR operation through capability information of the STA included in the association request frame. If the STA is capable of WUR operation, the AP may include subband information (i.e. WUR subband allocation information) to which the WUR packet is to be transmitted in the association response frame and transmit the same to the STA.
  • the subband information may include information about the location, size, and / or number of subbands to which the WUR packet is to be transmitted.
  • the subband information may be transmitted in the form of an information element or in the form of a subfield.
  • the AP may indicate the subband location using the WUR capabilities field element.
  • the AP may transmit information on the number of subbands (e.g., 4, 3, 2, 1 sub-band cases) and may also transmit the location of the subbands allocated to the corresponding STA.
  • the WUR capabilities field element may include, for example, an element ID (e.g., 1-octet), a length (e.g., 1-octet), and subband allocation information.
  • the subband allocation information may include the number of users, the number of subbands and / or the subband location.
  • the subband number information may correspond to a total of 2-bits.
  • the subband number information is (0, 0), 1-subband case; (0, 1); 2-subband case; (1, 0); 3-subband case; (1, 1) It may be a four subband case.
  • User number information may also correspond to 2-bit.
  • the number of users may be 1 user if (0, 0), 2-user if (0, 1), 3-user if (1, 0), or 4-user if (1, 1).
  • the subband location information may be indicated total number of users * 2-bit, and may indicate a location of a subband allocated to each user.
  • the AP may allocate 2-bit subbands. For example, in the 4-subband, 2 bits (0, 0) are subband 1, (0, 1) is subband 2, (1, 0) is subband 3, and (1, 1) is It may correspond to the fourth subband. In the case of three subbands, (1, 1) may not be used. For two subbands, (1, 0) and (1, 1) may not be used. Alternatively, in the case of 2 subbands, (1, 0) may correspond to subband 1 and (1, 1) corresponds to subband 2.
  • a 2-bit indicating a subband may be set for each user.
  • 2 bits (0, 0) are subband 1, (0, 1) is subband 2, (1, 0) is subband 3, and (1, 1) is It may correspond to the fourth subband.
  • (1, 1) may not be used.
  • (1, 0) and (1, 1) may not be used.
  • (1, 0) may correspond to subband 1
  • (1, 1) corresponds to subband 2.
  • subbands can be allocated with 1-bit information for each user. For example, when 1 bit is 0, subband 1 may be allocated, and when 1 bit, subband 2 may be allocated.
  • a 2-bit indicating a subband may be set for each user. For example, in the 4-subband, 2 bits (0, 0) are subband 1, (0, 1) is subband 2, (1, 0) is subband 3, and (1, 1) is It may correspond to the fourth subband. In the case of three subbands, (1, 1) may not be used.
  • a 2-bit indicating a subband may be set for each user. For example, two bits (0, 0) correspond to subband 1, (0, 1) corresponds to subband 2, (1, 0) corresponds to subband 3, and (1, 1) corresponds to subband 4. Can be.
  • the AP may allocate an additional frame to the WUR STA that performed the association and allocate a subband for WUR packet transmission.
  • a WUR request frame eg, WUR request frame
  • the AP transmits a frame (eg, WUR response frame, ACK, Block ACK, etc.) in response thereto. ) May include WU R subband information.
  • the AP may transmit subband allocation information through the information of the WUR capabilities field element.
  • the subband allocation information may include the number of users, the number of subbands and / or the subband location.
  • the method of allocating a subband through an association request / response frame or an additional frame after association is not limited to the 4 MHz subband and may be applied to the 5 MHz, 8 MHz, and 10 MHz (ie 32-subcarrier) subbands. .
  • the MU WUR packet may be transmitted using a narrow band within the 20 MHz band.
  • the narrow band may be a subband such as 4 MHz, 5 MHz, 8 MHz or 10 MHz. 38 shows an example of a narrow band.
  • FIG. 38 illustrates that the WUR packets are transmitted in parallel
  • the WUR packets may alternatively be cascaded.
  • a WUR packet may be transmitted in a hybrid manner of parallel transmission and cascade transmission, parallel on the frequency axis but cascaded on the time axis.
  • the spectral efficiency can be improved.
  • the AP can wake up a plurality of STAs at once, delay can be reduced as compared with the case of waking STAs individually.
  • FIG. 39 shows an example of cascade transmission.
  • a WUR packet of each STA is cascaded on a time axis on some narrow bands.
  • that narrow band includes 13-subcarriers.
  • Cascade transmission can also be performed on 5 MHz, 8 MHz, and 10 MHz narrow bands.
  • the bandwidth of each parallel narrow band is kept constant, and the WUR packet is cascaded on the time axis. In this case, the spectral efficiency can be improved compared to parallel transmission or cascade transmission through one narrow band.
  • the SIG field of the legacy part should have a duration value long enough to protect all cascaded WUR packets.
  • up to 4 4 MHz or 5 MHz narrow bands can be set in the 20 MHz band, and thus the AP can send up to 4 WUR packets simultaneously.
  • the AP can send up to two WUR packets simultaneously.
  • WUR packets in the frequency domain do not necessarily have to be transmitted on neighboring subbands. If the channel condition is poor, the AP may not transmit a WUR packet in some narrow bands among four narrow bands. As such, the narrow band allocation for the WUR packet transmission may be determined through negotiation between the AP and the STA.
  • Guard subcarriers may be set at both ends of the frequency domain, and null subcarriers may be set in the middle of WUR packets. The number and location of guard subcarriers and null subcarriers may also be determined through negotiation between the AP and the STA.
  • the bandwidth of the narrow band may vary.
  • the first WUR packet transmitted first in the time domain and the second WUR packet transmitted later may be transmitted through narrow bands having different bandwidths.
  • [WUR packet for WUR STA1 ',... , WUR packet for WUR STA N '] [WUR packet for WUR STA1,... , WUR packet for WUR STA N] may be transmitted through narrow bands having a different bandwidth.
  • narrowbands having different bandwidths at the same transmission timing may be used together.
  • the WUR packet for [WUR STA1 '' 'last transmitted in FIG. 41,... , WUR packet for WUR STA N '' '] is transmitted through narrow bands of different bandwidths.
  • Such a hybrid transmission scheme can improve the spectral efficiency compared to parallel transmission or cascade transmission. 41/42 also allows for more flexible WUR packet transmission.
  • FIG. 43 is a flowchart illustrating a method of transmitting a WUR packet according to an embodiment of the present invention. Descriptions overlapping with the above description may be omitted.
  • an AP selects at least one of a plurality of WUR subbands included in a primary connectivity radio (PCR) band (4305).
  • PCR primary connectivity radio
  • the AP transmits a WUR packet on the selected at least one WUR subband to wake up a plurality of stations (STAs) operating in WUR mode (4310).
  • STAs stations
  • the selection of the WUR subband may be performed in consideration of at least one of an STA identifier assigned to each of the plurality of STAs and an identifier of a basic service set (BSS) operated by the AP before entering the WUR mode.
  • the identifier of the STA may be an association identifier (AID) assigned through an association procedure, and the identifier of the BSS may be a BSS color or a BSSID.
  • the selection of at least one WUR subband may be performed by further considering the number of WUR subbands included in the PCR band.
  • the selection of the WUR subband is performed through a Modulo M operation on the STA identifier or the identifier of the BSS, and M may be the number of WUR subbands included in the PCR band.
  • the selection of at least one WUR subband may be performed by reusing the most significant 2-bit or the least significant 2-bit of the identifier of the BSS as the WUR subband index.
  • the WUR packet may be transmitted in a hybrid manner for multiple STAs in parallel transmission in the frequency domain and cascade transmission in the time domain.
  • the bandwidth of the PCR band corresponds to 20 MHz, and the bandwidth of each of the plurality of subbands may correspond to 4 MHz, 5 MHz, 8 MHz or 10 MHz.
  • At least one null subcarrier may be set between the plurality of subbands, and at least one guard subcarrier may be set at each end of the PCR band.
  • the STA may select the WUR subband in a similar manner to the AP and receive the corresponding WUR packet.
  • 44 is a view for explaining an apparatus for implementing the method as described above.
  • the wireless device 100 of FIG. 44 may correspond to a specific STA of the above-described description, and the wireless device 850 may correspond to the AP of the above-described description.
  • the STA 100 may include a processor 110, a memory 120, and a transceiver 130, and the AP 150 may include a processor 160, a memory 170, and a transceiver 180.
  • the transceivers 130 and 180 transmit / receive wireless signals and may be implemented in a physical layer, such as IEEE 802.11 / 3GPP.
  • Processors 110 and 160 run at the physical layer and / or MAC layer and are coupled to transceivers 130 and 180.
  • Processors 110 and 160 may perform the aforementioned UL MU scheduling procedure.
  • Processors 110 and 160 and / or transceivers 130 and 180 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processors.
  • the memories 120 and 170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage units.
  • ROM read-only memory
  • RAM random access memory
  • flash memory memory cards
  • storage media storage media and / or other storage units.
  • the method described above can be executed as a module (eg, process, function) that performs the functions described above.
  • the module may be stored in the memories 120 and 170 and may be executed by the processors 110 and 160.
  • the memories 120 and 170 may be disposed inside or outside the processes 110 and 160, and may be connected to the processes 110 and 160 by well-known means.
  • the transceiver 130 of the STA may include a transmitter (not shown) and a receiver (not shown).
  • the receiver of the STA may include a main connected radio receiver for receiving a main connected radio signal (eg, a wireless LAN such as IEEE 802.11 a / b / g / n / ac / ax) and a WUR receiver for receiving a WUR signal.
  • the transmitter of the STA may include a primary connected radio transmitter for transmitting the primary connected radio signal.
  • the transceiver 180 of the AP may include a transmitter (not shown) and a receiver (not shown).
  • the transmitter of the AP may correspond to an OFDM transmitter.
  • the AP may transmit the WUR payload by the OOK scheme by reusing the OFDM transmitter. For example, as described above, the AP may OOK modulate the WUR payload through an OFDM transmitter.
  • the present invention can be applied to various wireless communication systems including IEEE 802.11.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne, selon un mode de réalisation, un procédé de transmission d'un paquet de radio de réveil (WUR) par un point d'accès (AP) dans un système LAN sans fil (WLAN), lequel peut comprendre les étapes consistant : à sélectionner au moins une sous-bande parmi une pluralité de sous-bandes WUR incluses dans une bande radio à connectivité primaire (PCR) ; et à transmettre, par l'intermédiaire de ladite ou desdites sous-bandes WUR sélectionnées, un paquet WUR permettant de réveiller une pluralité de stations (STA) fonctionnant en mode WUR, la ou les sous-bandes WUR étant sélectionnées en considérant au moins l'un des identifiants de STA, attribués à la pluralité de STA respectivement avant que les STA n'entrent en mode WUR, et un identifiant d'un ensemble de services de base (BSS) géré par l'AP.
PCT/KR2017/014533 2017-01-05 2017-12-12 Procédé de transmission ou de réception d'un paquet de radio de réveil dans un système lan sans fil et appareil correspondant WO2018128293A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US201762442444P 2017-01-05 2017-01-05
US62/442,444 2017-01-05
US201762444795P 2017-01-10 2017-01-10
US62/444,795 2017-01-10
US201762455538P 2017-02-06 2017-02-06
US62/455,538 2017-02-06

Publications (1)

Publication Number Publication Date
WO2018128293A1 true WO2018128293A1 (fr) 2018-07-12

Family

ID=62791158

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2017/014533 WO2018128293A1 (fr) 2017-01-05 2017-12-12 Procédé de transmission ou de réception d'un paquet de radio de réveil dans un système lan sans fil et appareil correspondant

Country Status (1)

Country Link
WO (1) WO2018128293A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130336188A1 (en) * 2011-02-23 2013-12-19 Nec Communications Systems, Ltd. Wireless base station and wireless communication system using the same
WO2016028692A1 (fr) * 2014-08-20 2016-02-25 Qualcomm Incorporated Trames de radiomessagerie basse puissance
US20160337973A1 (en) * 2015-05-17 2016-11-17 Intel Corporation Apparatus, system and method of communicating a wakeup packet

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130336188A1 (en) * 2011-02-23 2013-12-19 Nec Communications Systems, Ltd. Wireless base station and wireless communication system using the same
WO2016028692A1 (fr) * 2014-08-20 2016-02-25 Qualcomm Incorporated Trames de radiomessagerie basse puissance
US20160337973A1 (en) * 2015-05-17 2016-11-17 Intel Corporation Apparatus, system and method of communicating a wakeup packet

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PARK, MINYOUNG ET AL.: "LP-WUR(Low- Power Wake-Up Receiver) Follow-Up", IEEE 802.11-16/0341R0, 14 March 2016 (2016-03-14), XP055534746 *
SEOK, YONGHO ET AL.: "Coexistence Mechanism for Wakeup Radio Signal", IEEE 802.11-16/1114R0, 26 August 2016 (2016-08-26), XP055480544 *

Similar Documents

Publication Publication Date Title
WO2018074740A1 (fr) Procédé d'émission et de réception de signal de réveil dans un système de réseau local (lan) sans fil, et appareil associé
WO2016186469A1 (fr) Procédé de gestion de vecteur d'attribution de réseau dans un système de réseau local sans fil et dispositif associé
WO2018097679A1 (fr) Procédé de transmission ou de réception de paquet radio de réveil dans un système lan sans fil, et appareil associé
WO2019124822A1 (fr) Procédé de transmission ou de réception d'une trame dans un lan sans fil, et dispositif correspondant
WO2016195402A1 (fr) Procédé d'exploitation en mode d'économie d'énergie dans un système lan sans fil et appareil associé
WO2019103452A1 (fr) Procédé de transmission ou de réception de trame dans un lan sans fil, et dispositif pour cela
WO2016182390A1 (fr) Procédé d'envoi ou de réception de trame dans un système lan sans fil, et appareil associé
WO2016200182A1 (fr) Procédé de gestion de vecteur d'attribution de réseau dans un système de réseau local sans fil, et dispositif associé
WO2018106006A1 (fr) Procédé de transmission ou de réception de trame de radio de réveil dans un système lan sans fil et appareil associé
WO2017099546A2 (fr) Procédé de transmission et de réception de trame dans un système lan sans fil, et appareil associé
WO2019194361A1 (fr) Procédé de transmission ou de réception de trame dans un système lan sans fil et appareil associé
WO2018062739A1 (fr) Procédé d'émission ou de réception de signal de réveil dans un système lan sans fil et dispositif associé
WO2016167438A1 (fr) Procédé d'émission/réception de signal dans un système de réseau local (lan) sans fil et dispositif s'y rapportant
WO2016182412A1 (fr) Procédé d'envoi ou de réception de trame dans un système lan sans fil et appareil associé
WO2018097699A1 (fr) Procédé de transmission ou de réception d'un paquet wake-up radio dans un système lan sans fil, et dispositif correspondant
WO2019182421A1 (fr) Procédé permettant de prendre en charge un processus harcq dans un système lan sans fil et terminal sans fil l'utilisant
WO2016182415A1 (fr) Procédé de fonctionnement en mode d'économie d'énergie dans un système lan sans fil et appareil s'y rapportant
WO2019088645A1 (fr) Procédé de transmission ou de réception de trame dans un système lan sans fil et appareil correspondant
WO2022260351A1 (fr) Procédé et dispositif de mise en œuvre de communication basée sur le temps de réveil cible dans un système lan sans fil
WO2019045380A1 (fr) Procédé et dispositif permettant de transmettre ou de recevoir une trame dans un système de réseau lan sans fil
WO2022240210A1 (fr) Procédé et appareil pour modifier une période de service dans un temps d'éveil cible dans un système lan sans fil
WO2019050135A1 (fr) Procédé d'émission ou de réception de signal dans un système lan sans fil, et dispositif associé
WO2020009389A1 (fr) Procédé et dispositif de transmission de ppdu dans un système lan sans fil
WO2023172068A1 (fr) Procédé et appareil basés sur une heure d'activation cible restreinte pour communiquer dans un système lan sans fil
WO2019045438A1 (fr) Procédé pour effectuer un fst dans un système de communication sans fil, procédé de prise en charge de fst et dispositif associé

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17890295

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17890295

Country of ref document: EP

Kind code of ref document: A1