WO2014065488A1 - Procédé d'émission-réception d'informations de carte d'indication de trafic - Google Patents

Procédé d'émission-réception d'informations de carte d'indication de trafic Download PDF

Info

Publication number
WO2014065488A1
WO2014065488A1 PCT/KR2013/006106 KR2013006106W WO2014065488A1 WO 2014065488 A1 WO2014065488 A1 WO 2014065488A1 KR 2013006106 W KR2013006106 W KR 2013006106W WO 2014065488 A1 WO2014065488 A1 WO 2014065488A1
Authority
WO
WIPO (PCT)
Prior art keywords
tim
segments
block
page
bitmap
Prior art date
Application number
PCT/KR2013/006106
Other languages
English (en)
Inventor
Wei Ping Sun
Yang Seok Jeong
Weon Yong Joo
Sung Hyun Choi
Jung Su Lee
Mun Hwan Choi
Hyun Pyo Kim
Original Assignee
Kt Corporation
Snu R&Db Foundation
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
Priority claimed from KR1020130013006A external-priority patent/KR101967747B1/ko
Application filed by Kt Corporation, Snu R&Db Foundation filed Critical Kt Corporation
Publication of WO2014065488A1 publication Critical patent/WO2014065488A1/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
    • H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
    • 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 wireless communication, and more particularly, to a method of transceiving traffic indication map (TIM) information that can reduce power consumption of a terminal and adjust a length of a beacon frame.
  • TIM traffic indication map
  • wireless LAN technology is a technology that wirelessly connects a portable terminal such as personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), or the like, to the Internet in homes, businesses or other specific service providing areas, based on wireless transmission technologies.
  • PDA personal digital assistant
  • PMP portable multimedia player
  • Wireless LAN technology is developed according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards.
  • IEEE 802.11a provides a transmission speed of 54 Mbps using unlicensed bands at 5 GHz.
  • IEEE 802.11b provides a transmission speed of 11 Mbps by applying a direct sequence spread spectrum (DSSS) method at 2.4 GHz.
  • IEEE 802.11g provides a transmission speed of 54 Mbps by applying orthogonal frequency division multiplexing (OFDM) at 2.4 GHz.
  • IEEE 802.11n provides a transmission speed of 300 Mbps with four spatial streams by applying multiple input multiple output-OFDM (MIMO-OFDM).
  • MIMO-OFDM multiple input multiple output-OFDM
  • wireless LAN terminals consume a large amount of power when transceiving data. Also, even in an idle listening state for transceiving data, the terminal may consume a significantly large amount of power.
  • awake state in which the terminal is awake and capable of transceiving data
  • doze state in which the wireless device turns off radio components that the power consumption is minimized.
  • an active mode that is always operated in the awake state and a power saving mode (hereinafter, referred to as “PS mode”) in which the awake state and the doze state are periodically repeated may be used.
  • PS mode power saving mode
  • a terminal that is set as the PS mode may be periodically awake, and check a beacon frame transmitted from an access point to determine whether a frame to be transmitted to the terminal is stored by the access point.
  • TIM traffic indication map
  • IE information element
  • PS Poll power-saving poll
  • Beacon interval that is a cycle in which the beacon frame is transmitted may be contained in the beacon frame, and the terminals that receive the beacon interval may estimate a target beacon transmission time (TBTT), which is a time when the beacon frame is transmitted.
  • TBTT target beacon transmission time
  • the access point may allocate association ID (hereinafter, referred to as “AID”) for each terminal so as to support the above-described PS mode, and terminals may determine presence or absence of a frame to be transmitted to the terminal among frames stored in a buffer of the access point, using a partial virtual bitmap of TIM IE included in the beacon frame.
  • AID association ID
  • An AID allocation range in an existing wireless LAN may be 1 to 2007. This is because the AID range that can be represented with the 2008 bits of the partial virtual bitmap is 0 to 2007, and AID 0 is used for representing a group address frame, and therefore AID values that can be allocated to the terminal are 1 to 2007.
  • a total number of the terminals that can be supported by a single access point is 2007.
  • a method that can support connection of a larger number of terminals compared to an existing method is required.
  • IEEE 802.11ah may be given.
  • the IEEE 802.11ah standard which is currently under development, may refer to a wireless LAN that uses a frequency band of 1 GHz or less, and the main application field is a smart grid using Wi-Fi, a sensor network, and the like.
  • the standardization that is currently being conducted, to enable communication between sensor terminals new wireless LAN-based technologies are actively being discussed.
  • a length of the beacon frame may be increased beyond tolerance due to the enormous size of the partial virtual bitmap.
  • the present invention is directed to providing a method of transmitting traffic indication map (TIM) information of an access point, which can reduce power consumption required for receiving a frame by a terminal and can adjust a length of a beacon frame.
  • TIM traffic indication map
  • the present invention is also directed to providing a method of receiving TIM information of a terminal, which can reduce power consumption required for receiving a frame by the terminal and can adjust the length of the beacon frame.
  • One aspect of the present invention provides a method of transmitting traffic indication map (TIM) information of an access point, in which a TIM transmission target page is divided into segments having variable sizes in a hierarchical TIM structure including a page, a block, and a sub-block, and TIM information of the TIM transmission target page is transmitted, the method including: (a) generating a delivery traffic indication map (DTIM) beacon including a segmentation information element; and (b) dividing the TIM information of the TIM transmission target page into the segments with variable sizes using the DTIM beacon and beacons within a DTIM interval corresponding to the DTIM beacon, and transmitting the divided segments.
  • DTIM delivery traffic indication map
  • the segmentation information element may include a page index designating the TIM transmission target page; page segment counts of the segments into which the TIM transmission target page is divided; a page offset designating a first block of the TIM transmission target page included in a first segment among the segments; and a page bitmap providing information about presence and absence of buffered data and information about segment division to blocks included in the segments.
  • the access point may divide the TIM information of the TIM transmission target page into the segments based on the number of blocks containing the buffered data included in the bitmap, and transmit the divided segments.
  • At least two of the segments may be divided so that the number of blocks containing the buffered data included in the bitmap corresponding to each of the segments in the bitmap is uniform.
  • the segmentation information element may include a page index designating the TIM transmission target page; a page offset designating a first block of the TIM transmission target page included in a first segment among the segments; and a page bitmap providing information about presence and absence of buffered data and information about segment division to blocks included in the segments.
  • the bitmap may include block traffic indication elements including predetermined bits which indicate the segment division with respect to a corresponding block and the presence and absence of the buffered data, and the access point may divide the TIM information of the TIM transmission target page into segments using the block traffic indication elements and transmit the divided segments.
  • the block traffic indication elements may have any one of a first value indicating absence of the buffered data with respect to the corresponding block; a second value indicating presence of the buffered data with respect to the corresponding block and indicating the corresponding block as a block in which a new segment starts; and a third value indicating presence of the buffered data with respect to the corresponding block and designating the corresponding block as a block included in a previous segment.
  • the bitmap may include a first bitmap indicating presence and absence of the buffered data with respect to a block to which each bit corresponds, and a second bitmap providing segment division information having the same length as the first bitmap by bit transition, and the access point may divide the TIM information of the TIM transmission target page into the segments using the second bitmap and transmit the divided segments.
  • Another aspect of the present invention provides a method of receiving TIM information of a terminal, in which TIM information of a TIM reception target page is received as divided segments with variable sizes in a hierarchical TIM structure including a page, a block and a sub-block, the method including: (a) receiving a DTIM beacon including a segmentation information element; and (b) receiving the TIM information of the TIM reception target page as the divided segments with the variable sizes using the DTIM beacon and beacons within a DTIM interval corresponding to the DTIM beacon.
  • the segmentation information element may include a page index designating the TIM reception target page; page segment counts of the segments into which the TIM reception target page is divided; a page offset designating a first block of the TIM reception target page included in a first segment among the segments; and a page bitmap providing information about presence and absence of buffered data and information about segment division to blocks included in the segments.
  • the terminal may divide the TIM information of the TIM reception target page into the segments based on the number of blocks containing the buffered data included in the bitmap, and receive the divided segments.
  • At least two among the segments may be divided so that the number of the blocks containing the buffered data included in the bitmap corresponding to each of the segments is uniform.
  • the segmentation information element may include a page index designating the TIM reception target page; a page offset designating a first block of the TIM reception target page included in a first segment among the segments; and a page bitmap providing information about presence and absence of buffered data and information about segment division to blocks included in the segments.
  • the bitmap may include block traffic indication elements including predetermined bits which indicate the segment division with respect to a corresponding block and the presence and absence of the buffered data, and the terminal may divide the TIM information of the TIM reception target page into segments using the block traffic indication elements and receive the divided segments.
  • the block traffic indication elements may have any one of a first value indicating absence of the buffered data with respect to the corresponding block; a second value indicating presence of the buffered data with respect to the corresponding block and indicating the corresponding block as a block in which a new segment starts; and a third value indicating presence of the buffered data with respect to the corresponding block and designating the corresponding block as a block included in a previous segment.
  • the bitmap may include a first bitmap indicating presence and absence of the buffered data with respect to a block to which each bit corresponds, and a second bitmap providing segment division information having the same length as the first bitmap by bit transition, and the access point may divide the TIM information of the TIM reception target page into the segments using the second bitmap and receive the divided segments.
  • a delivery traffic indication map (DTIM) beacon including segmentation information is generated, and the generated DTIM and TIM information corresponding to the DTIM beacon are divided into segments having a variable size to be transmitted.
  • downlink traffic stored in a buffer of an access point is appropriately distributed in a predetermined range, so that power consumption required for receiving a downlink frame stored in the buffer of the access point by terminals operated in a PS mode can be reduced.
  • only a single beacon frame is transmitted together with a single TIM segment, thereby appropriately adjusting a length of the beacon frame.
  • FIG. 1 shows a traffic indication map (TIM) information element (IE) format
  • FIG. 2 shows a PS mode operation defined in an 802.11 wireless LAN standard
  • FIG. 3 shows power loss of a terminal that can occur whenone or more frames stored in the buffer of the AP fails to be transmitted during a single beacon interval
  • FIG. 4 shows a PS mode operation to which a TIM segmentation method according to an embodiment of the present invention is applied
  • FIG. 5 shows a hierarchical association ID (AID) structure
  • FIG. 6 shows a TIM segmentation method considering a hierarchical AID structure
  • FIG. 7 shows a fixed length segmentation count IE format that can be used in a fixed length TIM segmentation method
  • FIG. 8 is a conceptual diagram showing utilization of fixed length segmentation
  • FIG. 9 shows an equal number of value-1 (ENV) segmentation count IE format that can be used in an ENV segmentation method according to an embodiment of the present invention
  • FIG. 10 is a conceptual diagram showing a difference between fixed length segmentation and ENV segmentation according to an embodiment of the present invention.
  • FIG. 11 is a conceptual diagram showing an example of utilizing ENV segmentation according to an embodiment of the present invention.
  • FIG. 12 is a conceptual diagram showing a block TI-based segmentation count IE format according to an embodiment of the present invention.
  • FIG. 13 is a conceptual diagram showing a page bitmap of a block TI-based segmentation count IE according to an embodiment of the present invention
  • FIG. 14 is a conceptual diagram showing a toggle-based segmentation count IE format according to an embodiment of the present invention.
  • FIG. 15 is a conceptual diagram showing a page bitmap of a toggle-based segment count IE according to an embodiment of the present invention.
  • FIG. 16 is a conceptual diagram showing a state of segmentation in a dynamic segmentation method according to an embodiment of the present invention.
  • FIG. 17 is a flowchart showing a method of transmitting TIM information of an access point according to an embodiment of the present invention.
  • FIG. 18 is a flowchart showing a method of receiving TIM information of a terminal according to an embodiment of the present invention.
  • station denotes an arbitrary functional medium including a medium access control (MAC) layer defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface with respect to a wireless medium.
  • STAs may be divided into STAs that are access points (APs) and STAs that are not APs.
  • An STA that is an AP may be simply referred to as an AP, and an STA that is not an AP may be simply referred to as a terminal.
  • the terminal may include a processor and a transceiver, and may further include a user interface, a display device, and the like.
  • the processor denotes a unit that is designed to generate a frame to be transmitted through a wireless network or process a frame received through the wireless network, and performs a variety of functions for controlling the station (STA).
  • the transceiver may be functionally connected with the processor, and denotes a unit that is designed to transmit and receive a frame through the wireless network for the STA.
  • the AP may refer to a centralized controller, a base station (BS), a Node-B, an eNode-B, a base transceiver system, a site controller, or the like, and may include some or all functions thereof.
  • BS base station
  • Node-B Node-B
  • eNode-B a base transceiver system
  • site controller or the like
  • the terminal may refer to a wireless transmit/receive unit (WTRU), user equipment (UE), a user terminal (UT), an access terminal (AT), a mobile station (MS), a mobile terminal, a subscriber unit, a subscriber station (SS), a wireless device, a mobile subscriber unit, or the like, and may include some or all functions thereof.
  • WTRU wireless transmit/receive unit
  • UE user equipment
  • UT user terminal
  • AT access terminal
  • MS mobile station
  • SS subscriber station
  • wireless device a mobile subscriber unit, or the like, and may include some or all functions thereof.
  • the terminal may be a desktop computer enabling communication, a laptop computer, a tablet PC, a wireless phone, a mobile phone, a smart phone, an e-book reader, a portable multimedia player (PMP), a portable game console, a navigation device, a digital camera, a digital multimedia broadcasting (DMB) player, a digital audio recorder, a digital audio player, a digital picture recorder, a digital picture player, a digital video recorder, a digital video player, or the like.
  • PMP portable multimedia player
  • DMB digital multimedia broadcasting
  • FIG. 1 shows a traffic indication map (TIM) information element (IE) format.
  • TIM traffic indication map
  • IE information element
  • TIM IE may include a delivery traffic indication map (DTIM) count required in a PS mode, a DTIM period, a bitmap control, and a partial virtual bitmap.
  • DTIM delivery traffic indication map
  • the DTIM count is used to indicate number of remaining beacon frames until next DTIM beacon transmission, and is a value that is circulated while being decreased from DTIM Period-1 to 0 every time a beacon frame is transmitted.
  • a current TIM IE is a DTIM indicating that a group-addressed frame is to be transmitted soon.
  • the DTIM Period is the number of beacon intervals within two consecutive DTIMs.
  • the DTIM Period value is 3, a broadcast/multicast frame may be transmitted for each of three beacon intervals.
  • a first bit of the bitmap control is a bit corresponding to associated ID (hereinafter, referred to as “AID”) 0, and AID 0 may be used for indicating whether a group-addressed frame is stored in AP.
  • the remaining 7 bits may be used for offset with respect to a partial virtual bitmap of a next region.
  • a traffic-indication virtual bitmap may have a length of 2008 bits, and each bit may indicate presence/absence of AP’s buffered traffic destined to a certain terminal . That is, a case in which a frame to be transmitted to a terminal is stored in the buffer of the AP can be displayed as 1, and other cases can be displayed as 0.
  • the case in which the frame to be transmitted to the terminal is stored in the buffer of the AP can be displayed as 0, and other cases can be displayed as 1.
  • the case in which the frame to be transmitted to the terminal is stored in the buffer of the AP is displayed as 1.
  • FIG. 2 shows a PS mode operation defined in an 802.11 wireless LAN standard.
  • a DTIM interval value is 3
  • four terminals maintain doze state in order to reduce power consumption, and then switch into an awake state in accordance with a target beacon transmission time (TBTT) to which a beacon frame is transmitted.
  • TBTT target beacon transmission time
  • the terminals that have received the beacon frame may determine presence or absence of frames that should be received by the terminals among frames stored in a buffer of an AP through a partial virtual bitmap included in a TIM IE.
  • a terminal having AID1 transmits a PS Poll to the AP based on bitmap information included in the first beacon so as to receive the frame stored in the buffer of the AP.
  • the AP that has received the PS Poll may transmit the frame stored in the buffer to the terminal having the AID1.
  • the terminal having the AID1 may return to the doze state.
  • the remaining terminals may remain awake to receive the beacon frame, determine whether a bit corresponding to the remaining terminals is set as 0 in the partial virtual bitmap, and then return to the doze state.
  • terminals may be awake for a required time period while repeatedly switching between the doze state and the awake state, and then return to the doze state to reduce power consumption when required transmission and reception of data is completed.
  • the above-described PS mode operation method may be an effective way to reduce power consumption by reducing a time during which terminals are unnecessarily awake compared to an active mode operation method in which terminals continuously remain awake to transmit and receive data.
  • terminal power loss that can occur when all of the frames stored in the buffer of the AP fail to be transmitted will be described with reference to FIG. 3.
  • FIG. 3 shows power loss of a terminal that can occur when a frame stored in the buffer of the AP fails to be transmitted during a single beacon interval.
  • terminals may determine presence or absence of frames that should be received by the terminals through a bitmap included in a first beacon.
  • the terminals in which a bit of a partial virtual bitmap included in the beacon is set as 1 may transmit a PS Poll to the AP so as to request transmission of frames.
  • a PS Poll may transmit a PS Poll to the AP so as to request transmission of frames.
  • the frame stored in the buffer of the AP fails to be transmitted to all of the terminals until the following beacon is transmitted.
  • a terminal having AID N-1 and a terminal having AID N may attempt to transmit the PS Poll so as to receive their own frames stored in the buffer of the AP, through the bitmap included in the first beacon.
  • the terminals may transmit the PS Poll in the next beacon interval, and receive their own frames.
  • An area displayed as a dotted border may indicate power loss that occurs by maintaining, by two terminals, an idle listening state for channel contending, which is different from the doze state, during a single beacon interval.
  • the two terminals may operate in the doze state in the first beacon interval to reduce power loss.
  • power loss occurred in FIG. 3 can be reduced by dividing a TIM into several segments, considering the amount of wireless resources that can be used to deliver the buffered traffic and the distribution of traffic stored in the buffer of the AP., and terminals corresponding to a single segment are allowed to be included in a single TIM IE.
  • a TIM segmentation method is proposed so that power consumption required for terminals operated in a PS mode to receive a downlink frame stored in the buffer of the AP is reduced by appropriately distributing downlink traffic stored in the buffer of the AP in a predetermined range.
  • the terminals may receive in advance, from the AP, information about the TBTT to which the TIM IE corresponding to the segment in which the terminals are involved is transmitted.
  • the terminals When aware of the information about the TBTT, the terminals may skip the beacon frame including the segment in which the terminals are not involved and therefore power consumption may be further reduced compared to an operation method in which the terminals are awake for each TBTT.
  • a partial virtual bitmap constituted of terminals corresponding to a single segment may be included in a single TIM IE, and therefore a length of the beacon frame can be appropriately adjusted compared to an existing method.
  • FIG. 4 shows a PS mode operation to which a TIM segmentation method according to an embodiment of the present invention is applied.
  • a TIM IE included in a first beacon frame includes a partial virtual bitmap that can cover AID 1 to AID M. Accordingly, the following beacon frame to be transmitted may include a partial virtual bitmap that can cover AID M+1 to AID N.
  • terminals included in the first segment may correspond to AID 1 to AID M
  • terminals included in the second segment may correspond to AID M+1 to AID N.
  • the terminals may receive in advance, from the AP, information about a TBTT to which a segment corresponding to the terminals is transmitted, the terminals may be awake only in the TBTT corresponding to the terminals.
  • the terminals included in the first segment are continuously operated in a doze state, not awake, in a second TBTT, and therefore power consumption can be reduced compared to the existing method.
  • terminals included in a second segment are operated in the doze state during the first beacon interval, power loss that can occur in the above-described unnecessary idle listening state may be effectively reduced.
  • FIG. 5 shows a hierarchical association ID (AID) structure.
  • eight terminals are included in a single sub-block, and eight sub-blocks may form a single block. That is, a single block may form a group including 64 terminals. Further, a single page including 32 blocks may include 2048 terminals in total, and the number of the pages is four. Accordingly, the hierarchical AID structure of FIG. 5 may include 8192 terminals in total.
  • FIG. 6 shows a TIM segmentation method considering a hierarchical AID structure.
  • page segmentation that can be thought as one example of the TIM segmentation will be described. That is, since the example uses the page as a unit of segmentation, the TIM segmentation shown in the present example may be referred to as page segmentation.
  • An AP may divide a single page into four segments and transmit the four segments together with a beacon frame for each segment.
  • terminals may be awake in accordance with the beacon frame including a segment in which the terminals are involved in order to reduce power consumption.
  • a DTIM period is 4, and the number of segments of the divided page is also 4. That is, the beacon including the DTIM may be transmitted for each of four beacon intervals, and a single page may be divided into four segments and the divided segments may be transmitted together with each of four beacon frames that are transmitted during a single DTIM interval.
  • a single page may be segmented in accordance with a DTIM beacon interval.
  • the segment count IE is a newly defined IE that can be used when the AP transmits TIM segmentation information to a terminal.
  • the IE may represent an AID range covered by each segment and presence and absence of traffic that is stored in a buffer of the AP for each block in a TIM segmentation process.
  • terminals may be aware of a time when the segment in which the terminals are involved is to be transmitted, that is, information about a TBTT to which the beacon frame including a corresponding segment is transmitted, and presence and absence of downlink traffic with respect to the block in which the terminals are involved. Accordingly, when there is downlink traffic with respect to the block in which the terminals are involved among the frames stored in the buffer of the AP, the terminals may be awake in accordance with a corresponding beacon frame, and therefore power loss that can occur when the terminals are unnecessarily awake can be reduced.
  • FIG. 7 shows a fixed length segmentation count IE format that can be used in a fixed length TIM segmentation method.
  • a fixed length segment count IE may include a large number of pieces of information such as a page index, format indication bits, a page segment count, page offset, a page bitmap, and the like, other than a length field in which an element ID and a length of IE used for referring to a segment count IE are represented in bytes, and may additionally include 2 reserved bits in order to set the entire length in bytes.
  • the page index may be used to represent a page to which segmentation information included in a current segment count IE corresponds.
  • the format indication bits may be used to indicate the segment count IEs having a variety of different formats according to an embodiment of the present invention.
  • the format indication bits are set as (0, 0)
  • the current count IE may be considered as a fixed length segment count IE.
  • the page segment count value may be used to represent the number of segments into which a single page is divided.
  • the page offset may be used as an offset value when displaying a page bitmap of a next region, and may be an index of a block that is displayed by a first bit of the page bitmap.
  • the page bitmap may be used to represent presence and absence of the frame stored in the buffer of the AP for each block. That is, a case in which a destination terminal of the frame stored in the buffer of the AP is among 64 terminals included in a single block is set as 1, and otherwise is set as 0.
  • the page bitmap may be increased up to 4 octets in order to represent TIM information of 32 blocks as a maximum.
  • the bit set as 0 may be skipped, and therefore an actual length of the page bitmap may be much shorter than 4 octets.
  • the page offset may have an index value of a block that is an actual starting point of the page bitmap based on the skipped bit.
  • the fixed length segment count IE may be used in a fixed length TIM segmentation method, which is the most basic segmentation method.
  • the fixed length TIM segmentation method may be a method of dividing a single page into segments having the same length.
  • the length may refer to the number of blocks. That is, the page segments transmitted during a single DTIM interval are divided so as to have the same number of blocks.
  • the page segment count value may differ between several DTIM intervals, and therefore the number of blocks of a single page segment may differ.
  • the length of the page segment generated in the above-described segmentation method may be represented as the following Equation1.
  • Length of page segment (Number of blocks in one page / page segment count)
  • a starting point and an end point of the page segment are represented as the following Equations 2 and 3, respectively.
  • Segment start page offset + ((length of page segment) ⁇ (page segment number -1)) + 1
  • Segment end page offset + length of page segment ⁇ TIM segment number
  • the traffic stored in the buffer of the AP corresponding to each segment may be not uniform.
  • the reason may be roughly interpreted in two aspects.
  • FIG. 8 is a conceptual diagram showing utilization of fixed length segmentation.
  • a length of the page bitmap is 3 octets, and a page segment count value is 4.
  • Terminals involved in each TIM segment may be awake in a corresponding TBTT in order to receive a beacon frame to which a TIM IE including a segment of the terminals is transmitted.
  • one bit may represent TIM information corresponding to a single block, an actual size of downlink traffic may differ for each block.
  • the traffic stored in the buffer of the actual AP may not be uniformly distributed.
  • only some among frames stored in the buffer of the AP corresponding to a first segment may be transmitted within a corresponding beacon interval, and the remaining frames may be delayed and transmitted within a second beacon interval. In this case, unnecessary terminal power loss that can occur when the TIM segmentation is not performed may still occur.
  • a TIM segmentation method in which a length of a TIM segment may vary in consideration of traffic distribution is proposed.
  • the variable TIM segmentation may effectively distribute traffic and reduce power consumption of the terminal.
  • variable TIM segmentation method an equal number of value-1, (hereinafter, referred to as “ENV”) Segmentation method and a dynamic segmentation method will be described.
  • ENV equal number of value-1
  • FIG. 9 shows an ENV segmentation count IE format that can be used in an ENV segmentation method according to an embodiment of the present invention
  • FIG. 10 is a conceptual diagram showing a difference between fixed length segmentation and ENV segmentation according to an embodiment of the present invention.
  • the page index may be used to represent which page information of the segment count IE corresponds to.
  • the page segment count may refer to the number of segments included in a single page.
  • the page offset may indicate an index of a block corresponding to a first bit of the page bitmap.
  • the page bitmap may be used to represent presence and absence of traffic stored in the buffer of the AP in the block unit as described above.
  • segmentation may be performed based on the number of 1s included in the page bitmap, unlike the fixed length segmentation method. That is, the number of 1s included in each TIM segment may be made the same by appropriately dividing the page bitmap. Therefore, when an amount of traffic stored in the buffer of the AP for each block is the same, an effect of uniformly distributing the traffic may be obtained.
  • FIG. 11 is a conceptual diagram showing an example of utilizing ENV segmentation according to an embodiment of the present invention.
  • each segment is segmented so as to include the same number of 1s existing in the page bitmap. That is, unlike FIG. 9, some blocks allocated to a first segment may be moved to a second segment, and corresponding terminals may be awake in accordance with a TBTT to which a second beacon different from a first beacon is transmitted.
  • an amount of wireless resources allowed for transmitting a frame stored in the buffer of the AP for each beacon interval may differ, and an amount of traffic stored in the buffer of the AP for each block may differ, and therefore the ENV segmentation may not be still an appropriate TIM segmentation method considering wireless resources.
  • a segment count IE capable of freely defining the number of blocks included in a single segment may be required.
  • a segment count IE that can be used in the above-described dynamic segmentation method is proposed.
  • a block TI-based segment count IE and a toggle-based segment count IE may exist, but any segment count IE may be used as long as the segment count IE has a format for supporting a TIM segmentation method capable of freely adjusting the number of blocks included in a single segment.
  • FIG. 12 is a conceptual diagram showing a block TI-based segmentation count IE format according to an embodiment of the present invention
  • FIG. 13 is a conceptual diagram showing a page bitmap of a block TI-based segmentation count IE according to an embodiment of the present invention.
  • format indication bits are set as (1, 0), and a corresponding segment count IE may be referred to as a block TI-based segment count IE.
  • TIM information corresponding to a single block in the page bitmap may be displayed as a block TI having 2 bits, and the meaning corresponding to the set value may be shown in the following Table 1.
  • Table 1 the meaning of a block TI value included in a page bitmap region in the block TI-based segment count IE is shown.
  • the block TI value When the block TI value is set as (0, 0), it may mean that a corresponding block does not have traffic stored in the buffer of the AP.
  • the block TI value when the block TI value is set as (0, 1), it may mean that a corresponding block has traffic to be transmitted from the AP and at the same time is a starting point of a new TIM segment. In addition, when the block TI value is set as (1, 0), it may mean that a corresponding block has traffic to be transmitted from the AP and is included in the same segment as the previous block.
  • the block TI value of (1, 1) may be used in a part which is required in the future.
  • the number of the block TIs which are set as (0, 1) among the page bitmap is four, and therefore a corresponding page may be divided into four TIM segments.
  • the remaining block TIs may have (0, 0) or (1, 0), and the corresponding meaning may be the same as defined in Table 1.
  • the AP may set the block TI value as (0, 1), and set the block TI value as (0, 0) or (1, 0) to continue the same segment. That is, the AP may appropriately perform TIM segmentation considering wireless resources as desired.
  • FIG. 14 is a conceptual diagram showing a toggle-based segmentation count IE format according to an embodiment of the present invention
  • FIG. 15 is a conceptual diagram showing a page bitmap of a toggle-based segment count IE according to an embodiment of the present invention.
  • a corresponding segment count IE follows a toggle-based segment count IE format by setting format indication bits as (1, 1).
  • the page bitmap may have the same format as the page bitmap that is defined in the fixed length segment count IE described in FIG. 7. That is, in the page bitmap, a case in which there is traffic to be transmitted from the AP by a corresponding block may be set as 1, and other cases may be set as 0.
  • the segmentation bitmap that is a next region may have the same length as the page bitmap and include information about a starting point and an end point of a segment.
  • FIG. 14 an example in which a new segment can start in a place where bit transition is performed is shown.
  • a block corresponding to a bit that is initially set as 1 after 0 may be a starting point of the next segment. Accordingly, a block having the same value as an immediately preceding block can be seen as a continuation of the same segment.
  • Bits of the page bitmap may be used to represent presence and absence of traffic, and bits of the segmentation bitmap may be used to represent a starting point and an end point of each segment. In FIG. 15, a case of division into four segments is shown.
  • FIG. 16 is a conceptual diagram showing a state of segmentation in a dynamic segmentation method according to an embodiment of the present invention.
  • an AP may apply an appropriate TIM segmentation method considering wireless resources using a segment count IE that can support the dynamic segmentation method described above.
  • Each TIM segment is appropriately segmented considering available wireless resources in a corresponding beacon interval.
  • terminals are awake to receive a beacon frame including a segment in which the terminals are involved, and then may receive, from an AP, a frame stored in a buffer of the AP before a TBTT to which the following beacon frame is transmitted.
  • FIG. 17 is a flowchart showing a method of transmitting TIM information of an AP according to an embodiment of the present invention.
  • the AP may generate a DTIM beacon including a segmentation information element.
  • the segmentation information element may include a page index designating a TIM transmission target page, a page segment count of segments obtained by dividing the TIM transmission target page, page offset designating a first block of the TIM transmission target page included in a first segment among the segments, and a bitmap providing information about presence and absence of buffered data with respect to blocks included in the segments and information about segment division.
  • the AP may divide TIM information of the TIM transmission target page into segments having variable sizes, using a DTIM beacon and beacons within a DTIM interval corresponding to the DTIM beacon.
  • the AP may divide TIM information of the TIM transmission target page into segments based on the number of blocks containing the buffered data included in the bitmap, and transmit the divided segments.
  • At least two of the segments may be divided so that the number of blocks in which the buffered data included in a bitmap part corresponding to each segment is uniform in the bitmap.
  • step S1723 when the bitmap includes segment division with respect to a corresponding block and block traffic indication elements including predetermined bits indicating presence and absence of the buffered data, the AP may divide the TIM information of the TIM transmission target page into segments using the block traffic indication elements, and transmit the divided segments.
  • the block traffic indication elements may have one of a first value indicating absence of the buffered data with respect to the corresponding block, a second value indicating presence of the buffered data with respect to the corresponding block and indicating that the corresponding block is a block in which a new segment starts, and a third value designating presence of the buffered data with respect to the corresponding block and indicating that the corresponding block is a block included in a previous segment.
  • step S1725 when the bitmap includes a first bitmap indicating presence and absence of the buffered data with respect to a block to which each bit corresponds, and a second bitmap having the same length as the first bitmap and providing segment division information by bit transition, the AP may divide the TIM information of the TIM transmission target page into segments using the second bitmap, and transmit the divided segments.
  • downlink traffic stored in the buffer of the AP is appropriately distributed within a predetermined range, and therefore power consumption required for receiving, by the terminals, downlink frames stored in the buffer of the AP can be reduced, and a length of the beacon frame can be appropriately adjusted.
  • FIG. 18 is a flowchart showing a method of receiving TIM information of a terminal according to an embodiment of the present invention.
  • a terminal may receive a DTIM beacon including a segmentation information element from an AP.
  • the segmentation information element may include a page index designating a TIM reception target page, a page segment count of segments into which the TIM reception target page is divided, a page offset designating a first block of the TIM reception target page included in a first segment among the segments, and a bitmap providing information about presence and absence of buffered data with respect to blocks included in the segments and information about segment division.
  • the terminal may receive the TIM information of the TIM reception target page as divided segments having variable sizes using the DTIM beacon received through step S1810 and beacons within a DTIM interval corresponding to the DTIM beacon.
  • the terminal may acquires the information about TIM segment division, and receives the divided segments based on the acquired division information.
  • the terminal may divide the TIM information of the TIM reception target page into segments based on the number of blocks containing buffered data included in the bitmap, and receive the divided segments.
  • At least two of the segments may be divided so that the number of the blocks in which the buffered data included in a bitmap part corresponding to each segment is uniform in the bitmap.
  • the terminal may divide the TIM information of the TIM reception target page into segments using the block traffic indication elements and receive the divided segments.
  • the block traffic indication elements may have any one of a first value indicating absence of the buffered data with respect to the corresponding block, a second value indicating presence of the buffered data with respect to the corresponding block and indicating that the corresponding block is a block in which a new segment starts, and a third value designating that the corresponding block is a block included in a previous segment.
  • the terminal may divide the TIM information of the TIM reception target page into segments using the second bitmap and receive the divided segments.
  • the downlink traffic stored in the buffer of the AP can be appropriately distributed in a predetermined range. Therefore, power consumption required for terminals operated in a PS mode to receive the downlink frames stored in the buffer of the AP can be reduced.

Landscapes

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

Abstract

La présente invention concerne un procédé, qui comprend la génération d'une balise de carte d'indication de trafic de livraison (DTIM) comprenant un élément d'information de segmentation et la division des informations TIM de la page cible d'émission TIM en segments avec des tailles variables, à l'aide de la balise DTIM et des balises dans un intervalle DTIM correspondant à la balise DTIM, ainsi que l'émission des segments divisés. En conséquence, un trafic en liaison descendante stocké dans un tampon d'un AP peut être correctement distribué dans une plage prédéfinie. Ainsi, la consommation d'énergie requise pour les terminaux actionnés en mode PS pour recevoir des trames en liaison descendante stockées dans le tampon de l'AP peut être réduite. En outre, seule une trame unique de balise peut être transmise avec un seul segment TIM. Ainsi, une taille de la trame de balise peut être correctement ajustée.
PCT/KR2013/006106 2012-10-22 2013-07-09 Procédé d'émission-réception d'informations de carte d'indication de trafic WO2014065488A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2012-0117041 2012-10-22
KR20120117041 2012-10-22
KR10-2013-0013006 2013-02-05
KR1020130013006A KR101967747B1 (ko) 2012-10-22 2013-02-05 Ｔｉｍ 정보 송수신 방법

Publications (1)

Publication Number Publication Date
WO2014065488A1 true WO2014065488A1 (fr) 2014-05-01

Family

ID=50544837

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2013/006106 WO2014065488A1 (fr) 2012-10-22 2013-07-09 Procédé d'émission-réception d'informations de carte d'indication de trafic

Country Status (1)

Country Link
WO (1) WO2014065488A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115208517A (zh) * 2022-07-14 2022-10-18 深圳市联平半导体有限公司 流量指示图的编码方法以及装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090154436A1 (en) * 2007-12-18 2009-06-18 Electronics And Telecommunications Research Institute Method and apparatus for transmitting data over wireless lan mesh network
US20090276646A1 (en) * 2008-05-02 2009-11-05 Samsung Electronics Co., Ltd. Method and apparatus for data transmission in wireless local access network and system therefor
US20100315983A1 (en) * 2009-06-12 2010-12-16 Samsung Electronics Co. Ltd. Method and apparatus for managing power of wlan module in portable terminal

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090154436A1 (en) * 2007-12-18 2009-06-18 Electronics And Telecommunications Research Institute Method and apparatus for transmitting data over wireless lan mesh network
US20090276646A1 (en) * 2008-05-02 2009-11-05 Samsung Electronics Co., Ltd. Method and apparatus for data transmission in wireless local access network and system therefor
US20100315983A1 (en) * 2009-06-12 2010-12-16 Samsung Electronics Co. Ltd. Method and apparatus for managing power of wlan module in portable terminal

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115208517A (zh) * 2022-07-14 2022-10-18 深圳市联平半导体有限公司 流量指示图的编码方法以及装置
CN115208517B (zh) * 2022-07-14 2023-07-14 深圳市联平半导体有限公司 流量指示图的编码方法以及装置

Similar Documents

Publication Publication Date Title
WO2014182090A1 (fr) Procédé permettant de pallier le problème de nœud caché dans un système wlan
WO2015023103A1 (fr) Procédé et dispositif de transmission de données dans un système wlan
WO2012047058A2 (fr) Appareil et procédé de prise en charge d'extension de couverture de cellule compacte dans un système de réseau hétérogène
WO2018070800A1 (fr) Procédé et appareil de négociation initiale dans un réseau local sans fil
WO2011021895A2 (fr) Procédé et dispositif de fonctionnement en mode veille dans un système à multiporteuses
WO2011112006A2 (fr) Procédé de communication d'un appareil de transmission et d'un appareil de réception
WO2010071312A2 (fr) Procédé de transmission et de réception de messages de radiomessagerie
WO2017113918A1 (fr) Procédé de communication basé sur une bande de fréquences sans licence, dispositif associé et système
WO2009148258A2 (fr) Procédé d'émission et de réception d'informations de radiomessagerie dans un système d'accès sans fil large bande
WO2018062905A1 (fr) Procédé et appareil de réduction de la consommation d'énergie basés sur un récepteur de réveil
WO2011087274A2 (fr) Appareil et procédé pour accéder à un canal d'accès aléatoire dans un système de communication sans fil
WO2014027765A1 (fr) Procédé d'accès à un canal dans un système de réseau local sans fil
WO2014142526A1 (fr) Procédé et appareil pour la communication sans fil
WO2015005675A1 (fr) Procédé et appareil pour transmettre des données dans un système lan sans fil
WO2010143925A9 (fr) Procédé de gestion efficiente de porteuses dans un système d'accès sans fil à large bande
WO2019035584A1 (fr) Procédé de transmission et de réception d'informations de réglage de créneau dans un système de communication
WO2012078000A2 (fr) Procédé d'accès entre un terminal et une station de base dans un système de communication sans fil, et appareil correspondant
WO2011129639A2 (fr) Procédé et appareil de mise à jour d'informations de système de service de diffusion/multidiffusion dans un système d'accès sans fil
WO2010101424A2 (fr) Procédé et appareil permettant de coordonner les performances de plusieurs porteuses
WO2018044056A1 (fr) Procédé de réduction de la consommation d'énergie via un indicateur de ressources d'accès aléatoire
WO2017119759A1 (fr) Procédé pour une gestion de puissance et terminal utilisant ledit procédé dans un système lan sans fil
WO2012091478A2 (fr) Procédé et appareil pour transmettre et recevoir des données relatives à la puissance de transmission d'un canal dans un système de communication sans fil
WO2020036455A1 (fr) Procédé de transmission ou de réception de signal de synchronisation dans un système v2x nr, et appareil associé
WO2021230556A1 (fr) Procédé et dispositif de communication de liaison latérale basée sur une drx
WO2014208983A1 (fr) Procédé et appareil de commande du trafic dans un système wlan

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: 13849466

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 17/08/2015)

122 Ep: pct application non-entry in european phase

Ref document number: 13849466

Country of ref document: EP

Kind code of ref document: A1