WO2018066909A1 - Procédé de transmission d'une trame dans un système lan sans fil et terminal sans fil correspondant - Google Patents

Procédé de transmission d'une trame dans un système lan sans fil et terminal sans fil correspondant Download PDF

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Publication number
WO2018066909A1
WO2018066909A1 PCT/KR2017/010905 KR2017010905W WO2018066909A1 WO 2018066909 A1 WO2018066909 A1 WO 2018066909A1 KR 2017010905 W KR2017010905 W KR 2017010905W WO 2018066909 A1 WO2018066909 A1 WO 2018066909A1
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directional
threshold level
sta
level
wireless
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PCT/KR2017/010905
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English (en)
Korean (ko)
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방세희
김진민
조한규
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엘지전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present disclosure relates to wireless communication, and more particularly, a method for transmitting a frame based on an omnidirectional channel clear assessment (CCA) procedure and a directional CCA procedure in a WLAN system and a wireless terminal using the same. It is about.
  • CCA channel clear assessment
  • the Institute of Electrical and Electronics Engineers (IEEE) 802.11ad standard is a high-speed wireless communications standard that operates in the band above 60 GHz.
  • the signal's reach is around 10 meters, but throughput can support more than 6 Gbps. Since operating in higher frequency bands, signal propagation is dominated by ray-like propagation.
  • Signal quality may be improved as the TX (remit) or RX (receive) antenna beam is aligned to face a strong spatial signal path.
  • IEEE 802.11ad provides a beamforming training process for antenna beam alignment.
  • IEEE 802.11ay is the next generation of standards under development aimed at throughputs of 20Gbps and higher based on IEEE 802.11ad.
  • An object of the present specification is to provide a method for transmitting a frame in a WLAN system having an improved performance and a wireless terminal using the same.
  • a first wireless terminal including a first directional antenna module and a second directional antenna module may be configured to determine a state of a wireless medium according to an omni-directional scheme. Performing an omnidirectional CCA procedure to determine; If the omni level obtained according to the omni-directional CCA procedure is lower than the preset first threshold level, the first wireless terminal compares the omni level and the second threshold level, wherein the second threshold level is greater than the first threshold level. Set low; And if the omnidirectional level is higher than the second threshold level, the first wireless terminal determines the state of the first wireless channel for the first directional antenna module and the second for the second directional antenna module. Separately performing a second directional CCA procedure to determine the state of the wireless channel.
  • a method for transmitting a frame in a WLAN system having improved performance and a wireless terminal using the same are provided.
  • FIG. 1 is a conceptual diagram illustrating a structure of a WLAN system.
  • FIG. 2 is a conceptual diagram of a layer architecture of a WLAN system supported by IEEE 802.11.
  • 3 is a conceptual diagram of an active scanning procedure.
  • FIG. 4 is a conceptual diagram of an STA supporting EDCA in a WLAN system.
  • 5 is a conceptual diagram illustrating a backoff procedure according to EDCA.
  • FIG. 6 is a view for explaining a frame transmission procedure in a WLAN system.
  • FIG. 7 is a conceptual diagram of a wireless terminal for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • FIG. 8 is a diagram illustrating channelization of a wireless channel for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • FIG. 9 illustrates a wireless terminal for checking a state of a wireless channel to transmit a frame in a wireless LAN system according to an embodiment of the present invention.
  • FIG. 10 is a diagram illustrating a relationship between a first threshold level and a second threshold level according to an exemplary embodiment.
  • FIG. 11 is a flowchart illustrating a method for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • FIG. 12 is a block diagram illustrating a wireless terminal to which an embodiment of the present specification can be applied.
  • FIG. 1 is a conceptual diagram illustrating a structure of a WLAN system.
  • FIG. 1A shows the structure of an infrastructure network of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.
  • IEEE Institute of Electrical and Electronic Engineers
  • the WLAN system 10 of FIG. 1A may include at least one basic service set (hereinafter, referred to as 'BSS', 100, 105).
  • the BSS is a set of access points (APs) and stations (STAs) that can successfully synchronize and communicate with each other, and is not a concept indicating a specific area.
  • APs access points
  • STAs stations
  • the first BSS 100 may include a first AP 110 and one first STA 100-1.
  • the second BSS 105 may include a second AP 130 and one or more STAs 105-1, 105-2.
  • the infrastructure BSS may include at least one STA, AP (110, 130) providing a distribution service (Distribution Service) and a distribution system (DS, 120) connecting a plurality of APs. have.
  • the distributed system 120 may connect the plurality of BSSs 100 and 105 to implement an extended service set 140 which is an extended service set.
  • the ESS 140 may be used as a term indicating one network to which at least one AP 110 or 130 is connected through the distributed system 120.
  • At least one AP included in one ESS 140 may have the same service set identification (hereinafter, referred to as SSID).
  • the portal 150 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).
  • a network between APs 110 and 130 and a network between APs 110 and 130 and STAs 100-1, 105-1, and 105-2 may be implemented. Can be.
  • FIG. 1B is a conceptual diagram illustrating an independent BSS.
  • the WLAN system 15 of FIG. 1B performs communication by setting a network between STAs without the APs 110 and 130, unlike FIG. 1A. It may be possible to.
  • a network that performs communication by establishing a network even between STAs without the APs 110 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).
  • BSS basic service set
  • the IBSS 15 is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. Thus, in the IBSS 15, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner.
  • All STAs 150-1, 150-2, 150-3, 155-4, and 155-5 of the IBSS may be mobile STAs, and access to a distributed system is not allowed. All STAs of the IBSS form a self-contained network.
  • the STA referred to herein includes a medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium.
  • MAC medium access control
  • IEEE Institute of Electrical and Electronics Engineers 802.11
  • any functional medium it can broadly be used to mean both an AP and a non-AP Non-AP Station (STA).
  • the STA referred to herein includes a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), and a mobile station (MS). It may also be called various names such as a mobile subscriber unit or simply a user.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • a hierarchical architecture of a WLAN system includes a physical medium dependent (PMD) sublayer 200, a physical layer convergence procedure (PLCP) sublayer ( 210 and a medium access control (MAC) sublayer 220.
  • PMD physical medium dependent
  • PLCP physical layer convergence procedure
  • MAC medium access control
  • the PMD sublayer 200 may serve as a transmission interface for transmitting and receiving data between a plurality of STAs.
  • the PLCP sublayer 210 is implemented such that the MAC sublayer 220 can operate with a minimum dependency on the PMD sublayer 200.
  • the PMD sublayer 200, the PLCP sublayer 210, and the MAC sublayer 220 may conceptually include management entities.
  • the management unit of the MAC sublayer 220 is referred to as a MAC Layer Management Entity (MLME) 225.
  • the management unit of the physical layer is referred to as a PHY Layer Management Entity (PLME) 215.
  • Such management units may provide an interface for performing a layer management operation.
  • the PLME 215 may be connected to the MLME 225 to perform management operations of the PLCP sublayer 210 and the PMD sublayer 200.
  • the MLME 225 may be connected to the PLME 215 to perform a management operation of the MAC sublayer 220.
  • a STA management entity (hereinafter, referred to as “SME”, 250) may exist.
  • the SME 250 may operate as an independent component in each layer.
  • the PLME 215, the MLME 225, and the SME 250 may transmit and receive information from each other based on primitives.
  • the PLCP sublayer 210 may include a MAC protocol data unit (MAC protocol data unit) received from the MAC sublayer 220 according to an indication of the MAC layer between the MAC sublayer 220 and the PMD sublayer 200.
  • MAC protocol data unit MAC protocol data unit
  • the MPDU is transmitted to the PMD sublayer 200 or the frame coming from the PMD sublayer 200 is transferred to the MAC sublayer 220.
  • the PMD sublayer 200 may be a PLCP lower layer to perform data transmission and reception between a plurality of STAs over a wireless medium.
  • the MPDU delivered by the MAC sublayer 220 is referred to as a physical service data unit (hereinafter, referred to as a PSDU) in the PLCP sublayer 210.
  • PSDU physical service data unit
  • the MPDU is similar to the PSDU. However, when an aggregated MPDU (AMPDU) that aggregates a plurality of MPDUs is delivered, individual MPDUs and PSDUs may be different from each other.
  • AMPDU aggregated MPDU
  • the PLCP sublayer 210 adds an additional field including information required by the transceiver of the physical layer in the process of receiving the PSDU from the MAC sublayer 220 and transmitting the PSDU to the PMD sublayer 200.
  • the added field may be a PLCP preamble, a PLCP header, tail bits required to return the convolutional encoder to a zero state in the PSDU.
  • the PLCP sublayer 210 adds the above-described fields to the PSDU to generate a PPCP (PLCP Protocol Data Unit), which is then transmitted to the receiving station via the PMD sublayer 200, and the receiving station receives the PPDU to receive the PLCP preamble and PLCP. Obtain and restore information necessary for data restoration from the header.
  • PPCP PLCP Protocol Data Unit
  • 3 is a conceptual diagram of an active scanning procedure.
  • the active scanning procedure may be performed in the following steps.
  • the STA 300 determines whether it is ready to perform a scanning procedure.
  • the STA 300 may perform active scanning by waiting until the probe delay time expires or when specific signaling information (eg, PHY-RXSTART.indication primitive) is received. have.
  • specific signaling information eg, PHY-RXSTART.indication primitive
  • the probe delay time is a delay generated before the STA 300 transmits the probe request frame 510 when performing the active scanning.
  • PHY-RXSTART.indication primitive is a signal transmitted from a physical (PHY) layer to a local medium access control (MAC) layer.
  • the PHY-RXSTART.indication primitive may signal to the MAC layer that it has received a PLC protocol data unit (PPDU) including a valid PLCP header in a physical layer convergence protocol (PLCP).
  • PPDU PLC protocol data unit
  • PLCP physical layer convergence protocol
  • DCF distributed coordination function
  • CSMA / CA carrier sense multiple access / collision avoidance
  • Probe request frame 310 for information (eg, service set identification (SSID) and basic service set identification (BSSID) information) for specifying APs 360 and 370 included in the MLME-SCAN.request primitive. ) Can be sent.
  • information eg, service set identification (SSID) and basic service set identification (BSSID) information
  • the BSSID is an indicator for specifying the AP and may have a value corresponding to the MAC address of the AP.
  • Service set identification (SSID) is a network name for specifying an AP that can be read by a person who operates an STA. The BSSID and / or SSID may be used to specify the AP.
  • the STA 300 may specify an AP based on information for specifying the APs 360 and 370 included by the MLME-SCAN.request primitive.
  • the specified APs 360 and 370 may transmit probe response frames 350 and 350 to the STA 300.
  • the STA 300 may unicast, multicast, or broadcast the probe request frame 310 by transmitting the SSID and BSSID information in the probe request frame 310. A method of unicasting, multicasting or broadcasting the probe request frame 310 using the SSID and the BSSID information will be further described with reference to FIG. 5.
  • the STA 500 may include the SSID list in the probe request frame 510 and transmit the SSID list.
  • the APs 360 and 370 receive the probe request frame 310 and determine the SSID included in the SSID list included in the received probe request frame 310 to determine the probe response frames 350 and 350 to the STA 300. You can decide whether to send.
  • the probe timer may be used to check the minimum channel time (MinChanneltime, 320) and the maximum channel time (MaxChanneltime, 530).
  • the minimum channel time 320 and the maximum channel time 330 may be used to control the active scanning operation of the STA 300.
  • the minimum channel time 320 may be used to perform an operation for changing the channel on which the STA 300 performs active scanning. For example, if the STA 300 does not receive the probe response frames 340 and 350 until the probe timer reaches the minimum channel time 320, the STA 300 shifts the scanning channel to scan on another channel. Can be performed. When the STA 300 receives the probe response frame 350 until the probe timer reaches the minimum channel time 320, when the probe timer reaches the maximum channel time 330, the STA may receive the received probe response frame ( 340 and 350 can be processed.
  • the STA 300 searches for the PHY-CCA.indication primitive until the probe timer reaches the minimum channel time 320 so that other frames (eg, probe response frames 340 and 350) are not available until the minimum channel time 320. Whether it is received by the STA 300 may be determined.
  • PHY-CCA.indication primitive may transmit information about the state of the medium from the physical layer to the MAC layer. PHY-CCA.indication primitive can inform the status of the current channel by using channel status parameters such as busy if channel is not available and idle if channel is available. When the PHY-CCA.indication is detected as busy, the STA 300 determines that there are probe response frames 350 and 350 received by the STA 300, and the PHY-CCA.indication is idle. If it is detected as, it may be determined that the probe response frames 340 and 350 received by the STA 300 do not exist.
  • the STA 300 may set the net allocation vector (NAV) to 0 and scan the next channel.
  • the STA 300 may perform processing on the received probe response frames 340 and 350 after the probe timer reaches the maximum channel time 330. have. After processing the received probe response frames 340 and 350, the net allocation vector (NAV) is set to 0, and the STA 300 may scan the next channel.
  • the PHY-CCA.indication according to the present specification is not a concept applied only to a probe response frame but may be applied to all frames transmitted to other physical layers.
  • the MLME may signal MLME-SCAN.confirm primitive.
  • the MLME-SCAN.confirm primitive may include a BSSDescriptionSet including all information obtained in the scanning process.
  • the STA 300 uses the active scanning method, it is necessary to perform monitoring to determine whether the parameter of the PHY-CCA.indication is busy until the probe timer reaches the minimum channel time.
  • MLME-SCAN.request primitive is a primitive generated by SME.
  • the MLME-SCAN.request primitive may be used to determine whether there is another BSS to which the STA is bound.
  • the MLME-SCAN.request primitive may specifically include information such as BSSType, BSSID, SSID, ScanType, ProbeDelay, ChannelList, MinChannelTime, MaxChannelTime, RequestInformation, SSID List, ChannelUsage, AccessNetworkType, HESSID, MeshID, VendorSpecificInfo.
  • a request parameter included in MLME-SCAN.request.primitive may be used to determine whether the responding STA transmits a probe response frame.
  • the request parameter may include information for requesting that information of another BSS is included in the probe response frame.
  • the request parameter may include a report request field, a delay reference field, and a maximum delay limit field.
  • the report request field is information for requesting information of another BSS to be included in the probe response frame.
  • the delay reference field includes information about a delay type applied in response to the probe request frame, and the maximum delay limit field is a delay reference field. It may include maximum connection delay information for the delay type, indicated by.
  • the request parameter may include a minimum data rate field and / or a received signal strength limit field.
  • the minimum data rate field contains information on the lowest overall data rate in transmitting an MSDU or A-MSDU.
  • the received signal strength limit field may further include information about a limit value of a signal required for the receiver of the probe request frame to respond.
  • FIG. 4 is a conceptual diagram of an STA supporting EDCA in a WLAN system.
  • an STA (or AP) that performs channel access based on enhanced distributed channel access (EDCA) may perform channel access according to a plurality of predefined user priorities for traffic data. .
  • EDCA enhanced distributed channel access
  • EDCA For the transmission of Quality of Service (QoS) data frames based on multiple user priorities, EDCA provides four access categories (AC) (AC_BK (background), AC_BE (best effort), AC_VI (video)). , AC_VO (voice)).
  • AC access categories
  • AC_BK background
  • AC_BE best effort
  • AC_VI video
  • AC_VO voice
  • the STA performing channel access based on the EDCA arrives at the medium access control (MAC) layer from the logical link control (LLC) layer, that is, traffic data such as a MAC service data unit (MSDU) as shown in Table 1 below. Can be mapped.
  • Table 1 is an exemplary table showing the mapping between user priority and AC.
  • transmission queues and AC parameters can be defined.
  • a plurality of user priorities may be implemented based on AC parameter values set differently for each AC.
  • DIFS DCF interframe space
  • DCF distributed coordination function
  • CWmin CWmax
  • AIFS artificial interframe space
  • the EDCA parameter used for the backoff procedure for each AC may be set to a default value or carried in a beacon frame from the AP to each STA.
  • the EDCA parameter set element may include information about channel access parameters for each AC (eg, AIFS [AC], CWmin [AC], CWmax [AC]).
  • the backoff procedure of EDCA which generates a new backoff count, is similar to the backoff procedure of the existing DCF.
  • Differentiated backoff procedure for each AC of the EDCA may be performed based on EDCA parameters set individually for each AC.
  • EDCA parameters can be an important means used to differentiate channel access of various user priority traffic.
  • EDCA parameter values defined for each AC can optimize network performance and increase the transmission effect of traffic priority. Accordingly, the AP may perform overall management and coordination functions for the EDCA parameters to ensure fair access to all STAs participating in the network.
  • a predefined (or pre-assigned) user priority for traffic data (or traffic) may be referred to as a traffic identifier ('TID').
  • Transmission priority of traffic data may be determined based on user priority.
  • the traffic identifier (TID) of the traffic data having the highest user priority may be set to '7'. That is, traffic data in which the traffic identifier (TID) is set to '7' may be understood as traffic having the highest transmission priority.
  • one STA (or AP) 1200 may include a virtual mapper 410, a plurality of transmission queues 420 to 450, and a virtual collision processor 1260.
  • the virtual mapper 410 of FIG. 4 may serve to map the MSDU received from the logical link control (LLC) layer to a transmission queue corresponding to each AC according to Table 1 above.
  • LLC logical link control
  • the plurality of transmission queues 420-450 of FIG. 4 may serve as individual EDCA competition entities for channel access to the wireless medium within one STA (or AP).
  • the transmission queue 420 of the AC VO type of FIG. 4 may include one frame 421 for a second STA (not shown).
  • the transmission queue 430 of the AC VI type has three frames 431 to 433 for the first STA (not shown) and one frame 434 for the third STA (not shown) according to the order to be transmitted to the physical layer. ) May be included.
  • the transmission queue 440 of the AC BE type of FIG. 4 includes one frame 441 for the second STA (not shown) and one frame for the third STA (not shown) according to the order to be transmitted to the physical layer. 442 and one frame 443 for the second STA (not shown).
  • the transmission queue 450 of the AC BE type may not include a frame to be transmitted to the physical layer.
  • internal backoff values for transmission queue 420 of AC VO type, transmission queue 430 of AC VI type, transmission queue 440 of AC BE type, and transmission queue 450 of type AC BK. can be calculated separately based on Equation 1 below and a set of channel access parameters for each AC (ie, AIFS [AC], CWmin [AC], CWmax [AC] in Table 2).
  • the STA 400 may perform an internal backoff procedure based on internal backoff values for each transmission queue 420, 430, 440, and 450.
  • the transmission queue that first completes the internal backoff procedure may be understood as the transmission queue corresponding to the primary AC.
  • Frames included in the transmission queue corresponding to the primary AC may be transmitted to another entity (eg, another STA or AP) during a transmission opportunity (TXOP). If two or more ACs that have completed the backoff exist at the same time, collisions between the ACs may be adjusted according to functions included in the virtual collision handler 460 (EDCA function, EDCAF).
  • EDCA function EDCAF
  • the STA may transmit the next frame in the same AC for the remaining TXOP time and determine whether it can receive an ACK. In this case, the STA attempts to transmit the next frame after the SIFS time interval.
  • the TXOP limit value may be set as a default value for the AP and the STA, or a frame associated with the TXOP limit value may be transferred from the AP to the STA. If the size of the data frame to be transmitted exceeds the TXOP limit, the STA may split the frame into several smaller frames. Subsequently, the divided frames may be transmitted within a range not exceeding the TXOP limit.
  • 5 is a conceptual diagram illustrating a backoff procedure according to EDCA.
  • Each STA may share a wireless medium based on a contention coordination function, a distributed coordination function (hereinafter, referred to as 'DCF').
  • DCF is an access protocol for coordinating collisions between STAs, and may use carrier sense multiple access / collision avoidance (CSMA / CA).
  • the STA may acquire a transmission right for transmitting an internally determined MPDU through the wireless medium.
  • the internally determined MPDU may be understood as a frame included in the transmission queue of the primary AC mentioned through FIG. 4.
  • the DCF determines that the wireless medium is used by another STA in the DIFS (ie, the wireless medium is busy)
  • the STA is idle for the wireless medium to obtain a transmission right to transmit an internally determined MPDU over the wireless medium. I can wait until it is in the idle state.
  • the STA may defer channel access by DIFS based on the time when the wireless medium is switched to the idle state. Subsequently, the STA may wait as much as a contention window (hereinafter referred to as "CW") set in the backoff counter.
  • CW contention window
  • each STA may set a randomly selected backoff value in the contention window (CW) to the backoff counter.
  • CW contention window
  • the backoff value set in the backoff counter of each STA to perform the backoff procedure according to the EDCA is equal to the internal backoff value used in the internal backoff procedure for determining the primary AC of each STA. May be associated.
  • the backoff value set in the backoff counter of each STA may be represented by Equation 1 below for the transmission queue of the primary AC of each STA and a channel access parameter set for each AC (that is, AIFS [AC] of Table 2, CWmin [AC], CWmax [AC]) may be a value newly set in the backoff counter of each STA.
  • a time indicating a backoff value selected by each STA in slot time units may be understood as the backoff window of FIG. 5.
  • Each STA may perform a countdown operation of decreasing the backoff window set in the backoff counter in slot time units.
  • An STA having a relatively shortest backoff window among a plurality of STAs may acquire a transmission opportunity (TXOP), which is a right to occupy a wireless medium.
  • TXOP transmission opportunity
  • the remaining STA may stop the countdown operation.
  • the remaining STA may wait until the time interval for the transmission opportunity (TXOP) ends.
  • the remaining STA may resume the suspended countdown operation to occupy the wireless medium.
  • the channel access scheme using DCF has no concept of transmission priority (ie, user priority). That is, when DCF is used, the quality of service (QoS) of traffic to be transmitted by the STA cannot be guaranteed.
  • HCF hybrid coordination function
  • HCCA HCCA controlled channel access
  • EDCA polling-based enhanced distributed channel access
  • the STA attempts to transmit buffered traffic data.
  • the user priority set for each traffic data may be differentiated as shown in Table 1.
  • the STA may include four types of output queues mapped to the user priorities of Table 1 (AC_BK, AC_BE, AC_VI, and AC_VO).
  • the STA may transmit traffic data based on the Arbitration Interframe Space (AIFS) in place of the previously used DCF Interframe Space (DIFS).
  • AIFS Arbitration Interframe Space
  • DIFS DCF Interframe Space
  • a wireless terminal ie, STA
  • STA may be a device capable of supporting both a WLAN system and a cellular system. That is, the wireless terminal may be interpreted as a UE supporting the cellular system or an STA supporting the WLAN system.
  • Interframe Interval can be reduced interframe space (RIFS), short interframe space (SIFS), PCF interframe space (PIFS), DCF frame interval (DIFS). It may be a DCF interframe space, an arbitration interframe space (AIFS), or an extended interframe space (EIFS).
  • RIFS reduced interframe space
  • SIFS short interframe space
  • PIFS PCF interframe space
  • DIFS DCF frame interval
  • AIFS arbitration interframe space
  • EIFS extended interframe space
  • the interframe interval may be determined according to an attribute specified by the physical layer of the STA regardless of the bit rate of the STA.
  • the rest of the interframe intervals (IFS) except for AIFS may be understood as fixed values for each physical layer.
  • AIFS can be set to a value corresponding to four types of transmission queues mapped to user priorities as shown in Table 2 above.
  • SIFS has the shortest time gap among the above mentioned IFS. Accordingly, the STA occupying the wireless medium may be used when it is necessary to maintain the occupancy of the medium without interference by other STAs in the section in which the frame exchange sequence is performed.
  • an STA accessing a wireless medium using SIFS may start transmission directly at the SIFS boundary without determining whether the medium is busy.
  • the duration of SIFS for a specific physical (PHY) layer may be defined by the aSIFSTime parameter.
  • the SIFS value is 16 ⁇ s.
  • PIFS can be used to provide the STA with the next highest priority after SIFS. In other words, PIFS can be used to obtain priority for accessing a wireless medium.
  • DIFS may be used by an STA to transmit a data frame (MPDU) and a management frame (Mac Protocol Data Unit (MPDU)) based on the DCF. If the medium is determined to be idle through a carrier sense (CS) mechanism after the received frame and the backoff time expire, the STA may transmit the frame.
  • MPDU data frame
  • MPDU Management frame
  • CS carrier sense
  • FIG. 6 is a view for explaining a frame transmission procedure in a WLAN system.
  • each STA 610, 620, 630, 640, and 650 of the WLAN system receives a backoff value for performing a backoff procedure according to EDCA.
  • 640 and 650 can be individually set to the backoff counters.
  • Each STA 610, 620, 630, 640, and 650 may attempt transmission after waiting for the set backoff value for a time indicated by a slot time (that is, the backoff window of FIG. 5).
  • each STA 610, 620, 630, 640, and 650 may reduce the backoff window in slot time units through a countdown operation.
  • the countdown operation for channel access to the wireless medium may be performed separately by each STA.
  • Each STA may individually set a backoff time Tb [i] corresponding to the backoff window to the backoff counter of each STA.
  • the backoff time Tb [i] is a pseudo-random integer value and may be calculated based on Equation 1 below.
  • Random (i) of Equation 1 is a function that uses a uniform distribution and generates a random integer between 0 and CW [i].
  • CW [i] may be understood as the contention window selected between the minimum contention window CWmin [i] and the maximum contention window CWmax [i].
  • the minimum contention window CWmin [i] and the maximum contention window CWmax [i] may correspond to the default values CWmin [AC] and CWmax [AC] of Table 2, respectively.
  • the STA may set CW [i] to CWmin [i] and use Random (i) to select a random integer between O and CWmin [i].
  • any integer selected can be referred to as a backoff value.
  • i in Equation 1 corresponds to the user priority in Table 1. That is, the traffic buffered in the STA may be understood to correspond to any one of AC_VO, AC_VI, AC_BE, or AC_BK of Table 1 based on the value set in i of Equation 1.
  • SlotTime of Equation 1 may be used to provide sufficient time for the preamble of the transmitting STA to be detected by the neighbor STA.
  • Slot Time of Equation 1 may be used to define the aforementioned PIFS and DIFS. As an example. Slot time may be 9 ⁇ s.
  • the initial backoff time Tb [7] for the transmission queue of type AC_VO slots the backoff value selected between 0 and CWmin [AC_VO]. It may be a time expressed in units of slot time.
  • the STA When collision between STAs occurs according to the backoff procedure (or when ACK frame for the transmitted frame is not received), the STA increases the backoff time Tb [i] 'based on Equation 2 below. Can be newly calculated.
  • the new contention window CW new [i] may be calculated based on the previous window CW old [i].
  • the PF value of Equation 2 may be calculated according to the procedure defined in the IEEE 802.11e standard. For example, the PF value of Equation 2 may be set to '2'.
  • the increased backoff time Tb [i] ' is equal to the slot time of any integer selected between 0 and the new contention window CW new [i]. It can be understood as time expressed in units.
  • CWmin [i], CWmax [i], AIFS [i], and PF values mentioned in FIG. 6 may be signaled from the AP through a QoS parameter set element, which is a management frame.
  • the CWmin [i], CWmax [i], AIFS [i] and PF values may be preset values by the AP and the STA.
  • the horizontal axes t1 to t5 for the first to fifth STAs 610 to 650 may represent time axes.
  • the vertical axis for the first to fifth STAs 610 to 650 may indicate a backoff time transmitted.
  • a plurality of STAs may attempt data (or frame) transmission.
  • each STA selects the backoff time (Tb [i]) of Equation 1 and waits for the corresponding slot time (slot time) before transmitting. You can try
  • each STA may count down the individually selected backoff counter time in slot time units. Each STA may continue to monitor the medium while counting down.
  • the STA may stop counting down and wait. If the wireless medium is monitored in an idle state, the STA can resume counting down.
  • the third STA 630 may check whether the medium is idle during DIFS. Subsequently, when the medium is determined to be idle during DIFS, the third STA 630 may transmit a frame to an AP (not shown).
  • IFS inter frame space
  • a frame may reach the MAC layer of each of the first STA 610, the second STA 620, and the fifth STA 650. If the medium is identified as idle, each STA may wait for DIFS and then count down the individual backoff time selected by each STA.
  • the second STA 620 selects the smallest backoff time and the first STA 610 selects the largest backoff time.
  • the remaining backoff time of the fifth STA 650 is the remaining back of the first STA 610 at the time T1 after completing the backoff procedure for the backoff time selected by the second STA 620 and starting frame transmission. A case shorter than the off time is shown.
  • the first STA 610 and the fifth STA 650 may suspend and wait for the backoff procedure. Subsequently, when the media occupation of the second STA 620 ends (that is, the medium is idle again), the first STA 610 and the fifth STA 650 may wait as long as DIFS.
  • the first STA 610 and the fifth STA 650 may resume the backoff procedure based on the stopped remaining backoff time.
  • the fifth STA 650 may complete the backoff procedure before the first STA 610. Can be.
  • a frame for the fourth STA 640 may reach the MAC layer of the fourth STA 640.
  • the fourth STA 640 may wait as long as DIFS. Subsequently, the fourth STA 640 may count down the backoff time selected by the fourth STA 640.
  • the remaining backoff time of the fifth STA 650 may coincide with the backoff time of the fourth STA 640. In this case, a collision may occur between the fourth STA 640 and the fifth STA 650. If a collision occurs between STAs, neither the fourth STA 640 nor the fifth STA 650 may receive an ACK, and may fail to transmit data.
  • the fourth STA 640 and the fifth STA 650 may individually calculate a new contention window CW new [i] according to Equation 2 above. Subsequently, the fourth STA 640 and the fifth STA 650 may separately perform countdowns for the newly calculated backoff time according to Equation 2 above.
  • the first STA 610 may wait. Subsequently, when the medium is idle, the first STA 610 may resume backoff counting after waiting for DIFS. When the remaining backoff time of the first STA 610 elapses, the first STA 610 may transmit a frame.
  • the CSMA / CA mechanism may include 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 uses a Network Allocation Vector (NAV).
  • NAV Network Allocation Vector
  • the NAV is a value that indicates to the other AP and / or STA how long the AP and / or STA currently using or authorized to use the medium 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 frame, and the STA receiving the NAV value is prohibited from accessing the medium during the period.
  • the NAV may be set according to a value of a duration field of the MAC header of the frame.
  • FIG. 7 is a conceptual diagram of a wireless terminal for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • the wireless terminal 700 includes a virtual mapper 710, a plurality of transmission queues 720 to 750, a virtual collision handler 760, and a plurality of directional antenna modules 770a to 770n. It may include.
  • the virtual mapper 710 of FIG. 7 the plurality of transmission queues 720 to 750, and the virtual collision handler 760 are described for the virtual mapper 410 of FIG. 4 and a plurality of transmissions. It will be understood as a description of the queues 420-450 and the virtual collision handler 1260.
  • the wireless terminal 700 has an internal structure in which a set of transmission queues 720, 730, 740, and 750 and a plurality of directional antenna modules 770a to 770n in the wireless terminal are associated. Can be.
  • the DMG antenna according to the present embodiment may include a plurality of physical antennas.
  • the DMG antenna according to the present embodiment may be understood as a set of a plurality of physical (or logical) antennas arranged in one direction.
  • the first directional antenna module 770a includes a first DMG antenna associated with a first user terminal (not shown), and the second directional antenna module 770b is associated with a second user terminal (not shown). It may include an associated second DMG antenna.
  • the third directional antenna module 770c may include a third DMG antenna associated with a third user terminal (not shown), and the Nth directional antenna module 770n (n is a natural number) may be an Nth STA (eg, N may include an N th DMG antenna associated with the natural number).
  • the wireless terminal 700 of FIG. 7 includes five directional antenna modules 770a to 770e.
  • the wireless terminal 700 of FIG. 7 includes a plurality of data frames 721 based on Receive Address (RA) information set in the plurality of data frames 721, 731 to 734, and 741 to 743, respectively.
  • 731 to 734 and 741 to 743 may be associated with a plurality of directional antenna modules 770a to 770n.
  • the first data frame 721 may be buffered in the transmission queue 720 of the AC VO type.
  • the first data frame 721 may be understood as an MPDU including reception address (RA) information indicating a first user terminal (not shown).
  • RA reception address
  • the second to fifth data frames 731 to 734 may be buffered in the transmission queue 730 of the AC VI type.
  • the second to fourth data frames 731, 732, and 733 may be understood as MPDUs including reception address (RA) information indicating a second user terminal (not shown).
  • the fifth data frame 734 may be understood as an MPDU including reception address (RA) information indicating a first user terminal (not shown).
  • Sixth to eighth data frames 741 to 743 may be buffered in the transmission queue 740 of the AC BE type.
  • the sixth data frame 741 may be understood as an MPDU including reception address (RA) information indicating a third user terminal (not shown).
  • RA reception address
  • the seventh data frame 742 may be understood as an MPDU including reception address (RA) information indicating a fourth user terminal (not shown).
  • the eighth data frame 743 may be understood as an MPDU including reception address (RA) information indicating a fifth user terminal (not shown).
  • Data frames buffered in the plurality of transmission queues according to the present embodiment may be transmitted through the respective directional antenna modules 770a to 770n according to the reception address information RA included in each data frame.
  • the first data frame 721 and the fifth data frame 734 may be transmitted via the first directional antenna module 770a.
  • the second to fourth data frames 731, 732, and 733 may be transmitted through the second directional antenna module 770b.
  • the sixth data frame 741 may be transmitted via the third directional antenna module 770c.
  • the seventh data frame 742 may be transmitted via the fourth directional antenna module 770d.
  • the eighth data frame 743 may be transmitted through the fifth directional antenna module 770e.
  • the existing wireless terminal may perform an omnidirectional clear channel assessment (CCA) procedure. Specifically, the existing STA may determine the state of the wireless medium by comparing the power level of the signal received from the physical layer of the wireless terminal for a predetermined time (for example, DIFS) with a preset threshold level in an omnidirectional manner. Can be.
  • CCA clear channel assessment
  • the state of the wireless medium may be determined to be an idle state. If the power level of the signal received from the physical layer is higher than the threshold level, the state of the wireless medium may be determined to be a busy state.
  • the wireless terminal 700 may cover a plurality of directions associated with the plurality of directional antenna modules 770a to 770n according to a directional method. Specifically, the wireless terminal 700 may perform a separate directional CCA procedure for a predetermined time for a plurality of wireless channels corresponding to a plurality of directions.
  • the wireless terminal 700 may individually determine the states of the plurality of wireless channels associated with the plurality of directional antenna modules 770a to 770n for the plurality of user terminals (not shown).
  • CCA directional clear channel assessment
  • Each of the plurality of directional antenna modules 770a to 770n may be associated with a wireless channel in a specific direction for each user terminal (not shown).
  • the wireless terminal according to the present embodiment may simultaneously perform a plurality of individual directional CCA procedures in a directional manner. That is, the first wireless channel is determined to be busy through a first directional CCA procedure for a first direction among a plurality of directions, and the second wireless channel is idle through a second directional CCA procedure for a second direction. It may be determined as an idle state.
  • the N-th wireless channel in the N-th direction for the N-th user terminal may be determined as an idle state (or busy state) through the directional CCA procedure.
  • the wireless terminal transmits data (or data frames) included in a transmission queue of the primary AC based on at least one directional antenna module associated with at least one wireless channel determined to be in an idle state. Can be.
  • the wireless terminal transmits the data frame and the secondary AC included in the transmission queue of the primary AC based on at least one directional antenna module associated with the at least one radio channel determined to be in an idle state. Data (or data frames) included in the queue can be transmitted together.
  • a plurality of directional antenna modules 770a-770n can be used to receive wireless signals transmitted from other wireless terminals.
  • the internal structure of the wireless terminal shown in FIG. 7 is only an example, and it will be appreciated that the wireless terminal of the present specification may be implemented based on a structure corresponding to a plurality of transmission modules and a plurality of antenna modules.
  • FIG. 8 is a diagram illustrating channelization of a wireless channel for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • the horizontal axis of FIG. 8 may represent a frequency (GHz) for the 60 GHz band.
  • the vertical axis of FIG. 8 may represent a level (dBr) of a signal relative to a maximum spectral density.
  • first to sixth channels ch # 1 to ch # 6 may be allocated.
  • a channel spacing for each of the first to sixth channels ch # 1 to ch # 6 may be 2160 MHz.
  • a channel center frequency for each of the first to sixth channels ch # 1 to ch # 6 may be defined based on Equation 3 below.
  • the channel starting frequency may be 56.16 GHz.
  • the first channel center frequency fc1 for the first channel ch # 1 may be 58.32 GHz.
  • the first channel ch # 1 of FIG. 8 may be defined between 57.24 GHz and 59.40 GHz.
  • the second channel center frequency fc2 for the second channel ch # 2 may be 60.48 GHz.
  • the first channel ch # 2 of FIG. 8 may be defined between 59.40 GHz and 61.56 GHz.
  • the third channel center frequency fc3 for the third channel ch # 3 may be 62.64 GHz.
  • the third channel ch # 3 of FIG. 8 may be defined between 61.56 GHz and 63.72 GHz.
  • the fourth channel center frequency fc4 for the fourth channel ch # 4 may be 64.80 GHz.
  • the fourth channel ch # 4 of FIG. 8 may be defined between 63.72 GHz and 65.88 GHz.
  • the fifth channel center frequency fc5 for the fifth channel ch # 5 may be 66.96 GHz.
  • the fifth channel ch # 5 of FIG. 8 may be defined between 65.88 GHz and 68.04 GHz.
  • the sixth channel center frequency fc6 for the sixth channel ch # 6 may be 69.12 GHz.
  • the sixth channel ch # 6 of FIG. 8 may be defined between 68.04 GHz and 70.2 GHz.
  • FIG. 9 illustrates a wireless terminal for checking a state of a wireless channel to transmit a frame in a wireless LAN system according to an embodiment of the present invention.
  • the WLAN system 900 includes a transmitting terminal STA # T for transmitting a frame and a plurality of receiving terminals (eg, STA # R1, STA # R2, and STA # R3) for receiving the frame. It may include.
  • the transmitting terminal STA # T of FIG. 9 performs an omni-directional channel clear assessment (CCA) procedure based on an omnidirectional scheme for a predetermined time (for example, DIFS) to transmit a buffered frame for each receiving terminal. Can be done.
  • CCA channel clear assessment
  • the transmitting terminal STA # T may determine the state of the wireless channel.
  • the transmitting terminal STA # T is configured to transmit power of a signal received for a predetermined time from all radio channels associated with the transmitting terminal STA # T in the non-directional region 910.
  • a non-directional level which is an average of n, may be compared with a predetermined first threshold level.
  • the transmitting terminal STA # T When the omni level is higher than the first threshold level, the transmitting terminal STA # T according to the present embodiment has a busy state in which a frame cannot be transmitted by the transmitting terminal STA # T. Can be determined to
  • the transmitting terminal STA # T adds the omnidirectional level and the second threshold level to determine the state of the radio channel according to the directional scheme. Can be compared.
  • the transmitting terminal STA # T has a first to third directivity for each of the plurality of directivity regions 921, 922, and 923.
  • the CCA procedure can be determined individually.
  • a transmitting terminal STA # T and a first receiving terminal STA # R1 may be associated based on a first wireless channel for the first directivity region 921.
  • the first wireless channel for the first directional region 921 may correspond to any one of the first to fourth channels ch # 1 to ch # 4 mentioned in FIG. 8.
  • the transmitting terminal STA # T and the second receiving terminal STA # R2 may be associated based on a second wireless channel for the second directivity region 922.
  • the second radio channel for the second directional region 922 may correspond to any one of the first to fourth channels ch # 1 to ch # 4 mentioned in FIG. 8.
  • the transmitting terminal STA # T and the third receiving terminal STA # R3 may be associated based on a third wireless channel for the third directivity region 923.
  • the third wireless channel for the third directivity region 923 may correspond to any one of the first to fourth channels ch # 1 to ch # 4 mentioned in FIG. 8.
  • the first to third radio channels for each of a plurality of receiving terminals are combined by a transmitting terminal STA # T. Can be determined.
  • the omni-directional CCA procedure and the directional CCA procedure according to the present embodiment may be performed by signal detection as well as energy detection.
  • the process of performing the omni-directional CCA procedure and the directional CCA procedure will be described in more detail with reference to the accompanying drawings.
  • FIG. 10 is a diagram illustrating a relationship between a first threshold level and a second threshold level according to an exemplary embodiment.
  • the omni level obtained according to the omni-directional CCA procedure may correspond to the first region 1010 of FIG. 10.
  • the omni level may be higher than the first threshold level T # 1.
  • the first threshold level T # 1 may be a value preset in the wireless terminal of the WLAN system.
  • the first threshold level T # 1 may be set to ⁇ 68 dBm.
  • the omni level obtained according to the omni-directional CCA procedure may correspond to the second region 1020.
  • the non-directional level may be lower than the first threshold level T # 1 and higher than the second threshold level T # 2.
  • the second threshold level T # 2 may be set to be lower than the first threshold level T # 1 by an offset level ⁇ g in consideration of the beamforming gain.
  • the second threshold level T # 2 may be set to ⁇ 82 dBm, which is 14 dBm lower than the threshold level T # 1.
  • the omni level obtained according to the omni-directional CCA procedure may belong to the third region 1030.
  • the input level may be lower than the second threshold level T # 2.
  • the second threshold level information according to the present embodiment may be obtained through a capability negotiation procedure performed for capability negotiation with another wireless terminal.
  • the capability negotiation procedure may be understood as a procedure performed after the discovery procedure and the authentication / combination procedure are completed in relation to other wireless terminals.
  • the second threshold level for the plurality of directional CCA procedures performed separately for the plurality of directional antenna modules of the wireless terminal may be set the same or different for each directional module.
  • the information on the second threshold level according to the present embodiment may be the same as or different from the threshold level for CCA mentioned in the existing 802.11 11ad standard document. If the information on the second threshold level is different from the threshold level of the 802.11 11ad standard document, the information on the second threshold level may be signaled using a separate frame.
  • the separate frame may be a beacon frame, a frame including an EDMG header, a frame including a MAC header, or a grant frame.
  • Information on whether the directional CCA procedure can be performed may be defined using 1 bit (or 2 bits) in a separate frame. For example, if 1 bit is indicated as '0', the wireless terminal may support a directional CCA procedure. As another example, if 1 bit is indicated as '1', the wireless terminal may not support the directional CCA procedure.
  • Information about the second threshold level for the directional CCA procedure may be defined using 1 bit (or n bits, n is a natural number of 2 or more).
  • the wireless terminal may obtain information about the second threshold level for the directional CCA procedure according to the index information received from another wireless terminal based on the table information for the second predetermined threshold level.
  • the wireless terminal according to the present embodiment may obtain information on a second threshold level for the directional CCA procedure based on gap information received from another wireless terminal.
  • the gap information may be a value corresponding to the difference between the first threshold level and the level for the omni-directional CCA procedure preset in the wireless terminal.
  • the gap information may be expressed by using a bit (eg, 14 dBm) corresponding to the difference between the first threshold level and the second threshold level.
  • the wireless terminal according to the present embodiment may separately manage the table for the gap information and obtain information on the second threshold level for the directional CCA procedure according to the index information received from another wireless terminal. .
  • the capability negotiation procedure with another wireless terminal may be required.
  • the information exchanged through the capability negotiation procedure may include information about a first threshold level for an omnidirectional CCA procedure in an omnidirectional manner.
  • the information on the first threshold level according to the present embodiment may be the same as or different from the threshold level for CCA mentioned in the existing 802.11 11ad standard document. If the information on the first threshold level is different from the threshold level of the 802.11 11ad standard document, the information on the first threshold level may be signaled using a separate frame.
  • the separate frame may be a beacon frame, a frame including an EDMG header, a frame including a MAC header, or a grant frame.
  • Information on whether the omni-directional CCA procedure can be performed may be defined using 1 bit (or 2 bits) in a separate frame.
  • the wireless terminal may support an omnidirectional CCA procedure.
  • the wireless terminal may not support the omni-directional CCA procedure.
  • Information about the first threshold level for the omni-directional CCA procedure may be defined using 1 bit (or n bits, n is a natural number of 2 or more).
  • the wireless terminal may obtain information on the first threshold level for the omni-directional CCA procedure according to the index information received from another wireless terminal based on the table information for the first threshold level.
  • the wireless terminal according to the present embodiment may obtain information on the first threshold level for the omni-directional CCA procedure based on gap information received from another wireless terminal.
  • Gap information includes a threshold level for the CCA procedure defined in the existing 802.11 11ad standard document (i.e. when the directional scheme is not supported) and an omnidirectional CCA procedure according to the present embodiment (i.e., the directional scheme). May be a value corresponding to a difference from the first threshold level (if supported).
  • the gap information may be set to a threshold level for the CCA procedure defined in the existing 802.11 11ad standard document (i.e., if the directional scheme is not supported) and the omnidirectional CCA procedure according to the present embodiment (i.e., The value corresponding to the difference from the first threshold level for the directivity scheme (if supported) may be represented using bits.
  • the wireless terminal according to the present embodiment may separately manage the table for the gap information and obtain information on the first threshold level for the omni-directional CCA procedure according to the index information received from the other wireless terminal. have.
  • the information on the first threshold level and the information on the second threshold level of the present specification may be transmitted using a reserved bit among frames defined in the existing 802.11 11ad standard document.
  • FIG. 11 is a flowchart illustrating a method for transmitting a frame in a WLAN system according to an exemplary embodiment.
  • the first wireless terminal referred to in FIG. 11 may be understood as the transmitting terminal STA # T mentioned in FIG. 9.
  • the second wireless terminal mentioned in FIG. 11 may be understood as the first receiving terminal STA # R1 mentioned in FIG. 9.
  • the third wireless terminal mentioned in FIG. 11 may be understood as the second receiving terminal STA # R2 mentioned in FIG. 9.
  • the third receiving terminal STA # R3 mentioned in FIG. 9 may not be considered.
  • the first wireless terminal ie STA # T in FIG. 9 is connected to the second wireless terminal via a first wireless channel associated with the first directional antenna module (ie, 770a in FIG. 7).
  • a first wireless channel associated with the first directional antenna module ie, 770a in FIG. 7.
  • STA # R1 of FIG. 9 and coupled with a third wireless terminal (STA # R2 of FIG. 9) via a second wireless channel associated with a second directional antenna module (ie, 770b of FIG. 7).
  • the first wireless terminal may perform an omni-directional channel clear assessment (CCA) procedure for determining a state of a wireless medium according to an omnidirectional manner. Can be.
  • CCA channel clear assessment
  • the omni-directional CCA procedure may be performed by the first wireless terminal for a predetermined time (eg, DIFS).
  • a predetermined time eg, DIFS
  • an omnidirectional level obtained according to an omnidirectional CCA procedure is received for a predetermined time in a first antenna module and a second antenna module corresponding to an omnidirectional region (910 of FIG. 9) of a wireless medium. It can be understood as the average of the power of the signal.
  • the first wireless terminal may compare the omnidirectional level obtained according to the omnidirectional CCA procedure with a preset first threshold level (eg, T # 1 of FIG. 10).
  • a preset first threshold level eg, T # 1 of FIG. 10
  • the first radio terminal transmits the radio medium to the frame regardless of the second threshold level (eg, T # 2 in FIG. 10). This may be determined as an incapable busy state. In this case, the procedure ends.
  • the second threshold level eg, T # 2 in FIG. 10
  • step S1130 may be performed.
  • the first wireless terminal may compare the omni level and the second threshold level (eg, T # 2 of FIG. 10) obtained according to the omni-directional CCA procedure.
  • the second threshold level may be set lower than the first threshold level.
  • the procedure may proceed directly to step S1160.
  • the first wireless terminal may skip the directional CCA procedure.
  • the first wireless terminal is directed to transmit the frame.
  • CCA procedures can be performed.
  • step S1140 may be performed.
  • the first wireless terminal determines a state of a first radio channel for the first directional antenna module and a second state of determining a state of a second radio channel for the second directional antenna module.
  • the directional CCA procedure can be performed separately.
  • the first directional CCA procedure and the second directional CCA procedure according to the present embodiment may be performed at the same time.
  • the third threshold level preset for the first directional CCA procedure and the second directional CCA procedure may be set lower than the second threshold level.
  • the first directivity level obtained according to the first directional CCA procedure may be lower than the third threshold level, and the second directivity level obtained according to the second directional CCA procedure may be higher than the third threshold level.
  • the first radio channel is determined to be an idle state capable of transmitting (or receiving) the frame, and the second radio channel is in a busy state in which transmission (or reception) of the frame is impossible. Can be judged.
  • the first directivity level obtained according to the first directional CCA procedure may be lower than the third threshold level
  • the second directivity level obtained according to the second directional CCA procedure may be lower than the third threshold level.
  • both the first wireless channel and the second wireless channel may be determined to be in an idle state.
  • the first wireless terminal may determine whether at least one wireless channel is in an idle state.
  • step S1140 If it is determined through step S1140 that there is no wireless channel in the idle state, the procedure is terminated. If it is determined through the above step S1140 that there is at least one radio channel in the idle state, step S1160 may be performed.
  • the first wireless terminal may transmit a frame (or data frame) based on the directional antenna module corresponding to the at least one wireless channel determined to be in the idle state.
  • FIG. 12 is a block diagram illustrating a wireless terminal to which an embodiment of the present specification can be applied.
  • the wireless terminal may be an STA or an AP or a non-AP STA, which may implement the above-described embodiment.
  • the wireless terminal may correspond to the above-described user or may correspond to a transmitting terminal for transmitting a signal to the user.
  • the AP 1200 includes a processor 1210, a memory 1220, and an RF unit 1230.
  • the RF unit 1230 may be connected to the processor 1210 to transmit / receive a radio signal.
  • the processor 1210 may implement the functions, processes, and / or methods proposed herein. For example, the processor 1210 may perform an operation according to the present embodiment described above. The processor 1210 may perform an operation of the AP disclosed in the present embodiment of FIGS. 1 to 11.
  • the non-AP STA 1250 includes a processor 1260, a memory 1270, and an RF unit 1280.
  • the RF unit 1280 may be connected to the processor 1260 to transmit / receive a radio signal.
  • the processor 1260 may implement the functions, processes, and / or methods proposed in the present embodiment.
  • the processor 1260 may be implemented to perform the non-AP STA operation according to the present embodiment described above.
  • the processor 1260 may perform an operation of the non-AP STA disclosed in the present embodiment of FIGS. 1 to 11.
  • Processors 1210 and 1260 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters to convert baseband signals and wireless signals to and from each other.
  • the memories 1220 and 1270 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.
  • the RF unit 1230 and 1280 may include one or more antennas for transmitting and / or receiving a radio signal.
  • the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in the memories 1220 and 1270 and executed by the processors 1210 and 1260.
  • the memories 1220 and 1270 may be inside or outside the processors 1210 and 1260, and may be connected to the processors 1210 and 1260 by various well-known means.
  • the non-AP STA 1250 includes a processor 1260, a memory 1270, and an RF unit 1280.
  • the RF unit 1280 may be connected to the processor 1260 to transmit / receive a radio signal.
  • the processor 1260 may implement the functions, processes, and / or methods proposed in the present embodiment.
  • the processor 1260 may be implemented to perform the non-AP STA operation according to the present embodiment described above.
  • the processor 1260 may perform an operation of the non-AP STA disclosed in the present embodiment of FIGS. 1 to 11.
  • Processors 1210 and 1260 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters to convert baseband signals and wireless signals to and from each other.
  • the memories 1220 and 1270 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.
  • the RF unit 1230 and 1280 may include one or more antennas for transmitting and / or receiving a radio signal.
  • the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in the memories 1220 and 1270 and executed by the processors 1210 and 1260.
  • the memories 1220 and 1270 may be inside or outside the processors 1210 and 1260, and may be connected to the processors 1210 and 1260 by various well-known means.

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Abstract

Selon un mode de réalisation de la présente invention, un procédé de transmission d'une trame dans un système LAN sans fil comprend les étapes consistant à : permettre à un premier terminal sans fil comprenant un premier module d'antenne directionnelle et un second module d'antenne directionnelle d'effectuer une procédure de CCA omnidirectionnelle pour déterminer l'état d'un support sans fil selon un procédé omnidirectionnel ; permettre au premier terminal sans fil de comparer un niveau omnidirectionnel avec un second niveau seuil si le niveau omnidirectionnel acquis selon la procédure de CCA omnidirectionnelle est inférieur à un premier niveau seuil prédéfini, le second niveau seuil étant réglé de façon à être inférieur au premier niveau seuil ; et permettre au premier terminal sans fil d'effectuer séparément une première procédure de CCA directionnelle afin de déterminer l'état d'un premier canal sans fil du premier module d'antenne directionnelle, ainsi qu'une seconde procédure de CCA directionnelle afin de déterminer l'état d'un second canal sans fil du second module d'antenne directionnelle, si le niveau omnidirectionnel est supérieur au second niveau de seuil.
PCT/KR2017/010905 2016-10-04 2017-09-29 Procédé de transmission d'une trame dans un système lan sans fil et terminal sans fil correspondant WO2018066909A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201662404136P 2016-10-04 2016-10-04
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