KR100585232B1 - Wireless lan media access control frame transmission system and method for enhanced distribution channel access block ack - Google Patents

Abstract

The present invention relates to an apparatus and method for transmitting a WLAN medium access control frame. According to the present invention, a wireless LAN apparatus for supporting EDCA BA provides a queue structure for managing a wireless medium access control frame according to TID information. In this way, the IEEE 802.11e standard can be efficiently supported.

WiFi, EDCA, BA, Transmission Queue, Frame

Description

WIRELESS LAN MEDIA ACCESS CONTROL FRAME TRANSMISSION SYSTEM AND METHOD FOR ENHANCED DISTRIBUTION CHANNEL ACCESS BLOCK ACK}

1 is a diagram illustrating an embodiment of a conventional static buffer operating method.

2 is a diagram illustrating an embodiment of a conventional dynamic buffer operating method.

3 is a diagram illustrating an enhanced distribution channel access (EDCA) block access (BA) supporting medium access control frame transmission queue structure according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of a transfer request register according to an embodiment of the present invention.

5 is a diagram illustrating a transport frame connection list according to an embodiment of the present invention.

6 is a diagram illustrating a configuration of an interrupt register according to an embodiment of the present invention.

7 illustrates a transport frame structure according to an embodiment of the present invention.

8 is a diagram illustrating a structure of a terminal transmission queue management according to an embodiment of the present invention.

The present invention relates to a wireless LAN media access control (MAC) frame transmission system, and more specifically, to the IEEE 802.11 standard (IEEE Std 802.11e / D5. The present invention relates to a method for transmitting a WLAN medium access control frame for supporting Enhanced Distribution Channel Access (EDCA) Block Ack (BA) that satisfies IEEE 802.11e).

Recently, the wireless LAN media access control protocol recommended by the IEEE 802.11 committee is different from the carrier sense multiple access with collision detection (CSMA / CD) scheme used in the wired local area network. After adopting the Sense Multiple Access with Collision Avoidance method, an additional specification is recommended to guarantee QoS.

Therefore, according to the user priority information delivered by the layer, the WLAN medium access control frames are stored in the top four transmission queues, and the frame transmission timing and method should be applied differently according to the internal competition between the transmission queues. Mechanisms to increase should be applied.

In order to transmit such a WLAN medium access control frame, an interface device for transferring a medium access control frame between a medium access control layer and a physical layer of a WLAN is required.

Conventional media access control frame transmission methods applicable to a wireless LAN include a static buffer operation method and a dynamic buffer operation method.

1 illustrates an embodiment of a static buffer operating method according to the prior art.

As shown in FIG. 1, the conventional static buffer operating method uses a statically allocated buffer for each port, and allocates a predetermined buffer for each port to the transmission frame buffer 120. ) Service is performed while rotating by reflecting in order. Since this method allocates each port for each mobile terminal, it is not suitable for use in a wireless LAN environment in which a plurality of mobile terminals exist, and there is a problem that a lot of wasted buffers exist.

2 shows an embodiment of a dynamic buffer management method according to the prior art.

As shown in FIG. 2, the conventional dynamic buffer management method is a method of operating a buffer dynamically allocated for each port. The buffer is allocated to the transmission frame buffer 220 according to the reception order, and the transmission queue table ( And store it in 210). Using this method reduces the waste of the buffer, but has a disadvantage in that it is impossible to efficiently find a frame for a specific mobile terminal.

In addition, since both the conventional static buffer operation method and the dynamic buffer operation method store frames in units of MAC Service Data Units (MSDUs), processing in units of MAC Protocol Data Units (MPDUs) is impossible, and buffer collisions reduce collisions. It is impossible to consider the problem. In addition, there is a problem that it is impossible to increase the transmission rate by applying a block Ack according to the TID (Traffic ID).

An object of the present invention is to provide a media access control frame transmission system and method for supporting Enhanced Distribution Channel Access (EDCA) Block Ack (BA) based on user priority information provided by a higher layer.

An apparatus for transmitting a WLAN medium access control frame for supporting Enhanced Distribution Channel Access (EDCA) Block Ack (BA) according to an aspect of the present invention for achieving the above object,

A destination address table for managing TID (Traffic ID) information required for each destination address; A TID queue table that manages a frame connection list for each TID generated for each destination address, and classifies the generated transmission frame according to a TID when a frame to be transmitted from an upper logical link control layer to a WLAN network card is generated; A frame storage unit for storing transmission frames classified according to the TID; A frame forwarding unit for forwarding the transmission frame to a corresponding transmission queue according to a Block Ack (BA) mechanism; And a frame transmitter for transmitting the frame using the interrupt register and the transfer request register.

The frame link list,

delete

delete

A queue connection list to be transmitted next including location information in which actual frames are stored for each TID; And a list of currently connected queue connections used when the list of frames determined to be transmitted by the BA mechanism is transmitted according to an access category and transmitted to the corresponding transmission queue.

The queue connection list currently being transmitted is

An AC_BK queue connection list for a background service; An AC_BE queue connection list for best effort services; An AC_VI queue connection list for video services; And an AC_VO queue connection list for the voice service.

In addition, the interrupt register,

An interrupt information register for notifying the content of the interrupt; And an interrupt control register for enabling or disabling the interrupt;

The transfer request register,

An AC_BK_TRQ register informing a request for transmission of a frame corresponding to the background service; An AC_BE_TRQ register informing a request for transmission of a frame corresponding to the best effort service; An AC_VI_TRQ register informing a request for transmission of a frame corresponding to the video service; And an AC_VO_TRQ register indicating a request for transmission of a frame corresponding to the voice service.

The structure of the transport frame,

A WLAN network card control area for allowing the WLAN network card to reflect a frame transmission result; A frame configuration information area for allowing a WLAN network card to efficiently transmit a frame; And a management MAC protocol data unit (MMPDU) or a MAC service data unit (MSDU) area in which frames actually transmitted are stored.

The WLAN network card control area,

A valid bit (V) indicating whether the frame is valid; And a transmission error bit (TE) indicating a transmission failure of the frame.

The frame configuration information area is

RC (RTS / CTS) bit indicating whether to send a Request to Send / Clear to Send (RTS / CTS) mechanism; A List End (LE) bit specifying the end of the frame list; An MSDU End (ME) bit indicating the end of the MSDU; An MSDU Begin (MB) bit indicating the start of an MSDU; And a CE (Chunk End) bit indicating discontinuity of the area where the frame is stored.

The structure of the transport frame,

A last MPDU location information area for efficiently handling transmission errors; A next MPDU location information area containing location information of a transport frame structure to be transmitted next to the current transport frame structure; A destination medium access control address information area for facilitating the RTS / CTS mechanism in accordance with the specification of the WLAN medium access control layer; And a transmission vector information region including information required for the physical layer unit.

According to an aspect of the present invention, a method for transmitting a WLAN medium access control frame for supporting Enhanced Distribution Channel Access (EDCA) Block Ack (BA),

a) generating a medium access control frame when a frame to be transmitted from the upper logical link control layer to the WLAN network card occurs; b) classifying and storing the media access control frame according to TID (Traffic ID) information of the media access control frame; c) constructing a new frame list to be transmitted next by referring to the corresponding transmission queue table according to the information of the queue transmission register; d) confirming a frame to be transmitted from the frame list according to a Block Ack (BA) mechanism, and notifying the WLAN network card of a request for transmission of the confirmed frame; And e) transmitting the frame using an interrupt register and a transfer request register.

delete

delete

Step d),

When the frame to be transmitted is confirmed, the transmission request register value is set to 1 to inform the WLAN network card of the frame transmission request.

Further, after step e),

And receiving a frame transmission completion result of setting the transmission request register value to 0 from the WLAN network card.

In step e),

The WLAN network card determines whether to apply RTS / CTS (Request to Send / Clear to Send), the transmission interval, whether to increase or decrease the position of the frame, and whether to use the position information of the next MPDU with reference to the frame information.

When transmitting the last list of frames, the interrupt register is notified that the frame is requested to be sent.

Further, after step e),

When the current frame transmission is completed, the method may further include transmitting a frame requesting a transmission result through a queue for voice service according to the BA mechanism.

Further, in step e),

In case of retransmitting the divided frame, if retransmission of the frame fails, it moves to the start position of the next MSDU using the last MSDU position information of the frame currently being transmitted.

delete

delete

Step d),

Providing a frame association list having the TID of 0 to a queue for a best effort service, providing a frame association list having the TID of 1 or 2 to a queue for the background service, and having the TID of 3 or A frame connection list of 4 or 5 is provided to the queue for video service, and a frame connection list of 6 or 7 is provided to the queue for the voice service.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

First, a medium access control frame transmission system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 illustrates a configuration of an apparatus for transmitting a media access control frame for supporting Enhanced Distribution Channel Access (EDCA) Block Ack (BA) according to an embodiment of the present invention.

As shown in FIG. 3, the apparatus for transmitting a media access control frame for EDCA BA support according to an embodiment of the present invention includes a destination address table 310, a TID queue table 320, and a queue connection list 330 to be transmitted next. 340 and 350 and the connection list 360, 370, 380 and 390 currently being transmitted.

The destination address table 310 manages a TID table required for each destination address, and the TID queue table 320 manages a frame connection list for each TID generated for each destination address, and a queue connection list 330, 340, 350 to be transmitted next. ) Includes location information where an actual frame is stored for each TID.

In addition, the connection list 360, 370, 380, 390 currently being transmitted is used when the frame list determined to be transmitted by the BA mechanism is transmitted according to the access category and transmitted to the corresponding queue. AC_BK Queue Connection List 360, AC_BE Queue Connection List 370 for Best Effort Service, AC_VI Queue Connection List 380 for Video Service, and AC_VO Queue for Voice Service A linked list 390 is included.

The process of transmitting a frame in the transmission queue according to the embodiment of the present invention shown in FIG. 3 is as follows.

First, the BA mechanism transmits a frame ADDBA for BA setup through the AC_VO queue 390. When a frame to be transmitted is determined after successful BA setup, a request for transmission of a frame to the WLAN network card is performed using a transmission request register. Inform.

4 illustrates a structure of a transfer request register according to an embodiment of the present invention.

As shown in FIG. 4, an AC_BK_TRQ register 410, an AC_BE_TRQ register 420, an AC_VI_TRQ register 430, and an AC_VO_TRQ register 440 are included.

The AC_BK_TRQ register 410 notifies a request for transmission of a frame corresponding to a background service, and the AC_BE_TRQ register 420 notifies a request for transmission of a frame corresponding to a best effort service. The AC_VI_TRQ register 430 notifies a request for transmission of a frame corresponding to a video service, and the AC_VO_TRQ register 440 notifies a request for transmission of a frame corresponding to a voice service.

When the value of the transmission request register is set to '1' to inform the WLAN network card of the frame transmission request, the WLAN network card transmits all the requested frames and then sets the transmission request register value to '0' to transmit the result. Inform.

Also, the wireless network card determines whether to apply Request to Send / Clear to Send (RTS / CTS) with reference to the frame configuration information area (511 of FIG. 5) of the frame, and uses bit information indicating the start and end of the MSDU. The transmission interval is determined, and whether or not to increase the position of the frame by the slot size according to the continuity of the position in which the frame is stored and to determine whether to use the position information of the next MPDU.

5 illustrates a queue connection list 510 of a transmission frame according to an embodiment of the present invention. In FIG. 5, 511 represents a frame configuration information area.

In addition, in the case of transmitting the end of the frame list, the interrupt register notifies that the frame is requested to be transmitted.

6 illustrates the structure of an interrupt register according to an embodiment of the present invention.

As shown in FIG. 6, an interrupt register according to an embodiment of the present invention includes an interrupt information register 610 and an interrupt control register 620.

The interrupt information register 610 is utilized to inform the contents of the interrupt, and the interrupt control register 620 is used to enable or disable the interrupt.

That is, the interrupt register sets a specific bit of the interrupt information register 610 to '1' and then uses the interrupt control register 620 to notify the fact of the interrupt so that the interrupt can be processed.

Meanwhile, after the current frame is transmitted, a request is made to transmit a frame BlackAckReq through the AC_VO queue 390 by the BA mechanism.

In addition, when retransmission of the divided frame fails, the position information of the last MSDU of the transmission frame structure is used to move quickly to the start of the next MSDU. By doing in this way, transmission performance can be improved rather than continuing to move the several positional information of a divided frame.

7 illustrates a transport frame structure according to an embodiment of the present invention.

As shown in FIG. 7, the transmission frame structure according to the embodiment of the present invention includes a WLAN network card control area 710, a frame configuration information area 720, a last MPDU location information area 730, and next MPDU location information. Area 740, receiving MAC address information area 750, transmission vector information area 760, and (divided) Management MAC Protocol Data Unit (MMPDU) or MAC Service Data Unit (MSDU) 770.

The WLAN network card control area 710 is for reflecting the frame transmission result, and includes a valid bit (V) indicating whether a frame is valid and a transmission error bit (TE) indicating a frame transmission failure. It consists of.

The frame configuration information area 720 includes an RC (RTS / CTS) bit indicating whether the RTS / CTS mechanism is transmitted, a LE (List End) bit indicating the end of the frame list, an MSDU End (ME) bit indicating the end of the MSDU, It includes the MB (MSDU Begin) bit indicating the start of the MSDU and the Chunk End (CE) bit indicating the discontinuity of the region in which the frame is stored.

The last MPDU location information area 730 is for efficiently handling transmission errors, and the next MPDU location information area 740 includes location information of a transport frame structure to be transmitted next to the current transport frame structure.

The destination media access control address information area 750 is for facilitating the RTS / CTS mechanism in accordance with the specification of the WLAN media access control layer, and is a (divided) Management MAC Protocol Data Unit (MMPDU) or MAC Service Data (MSDU). Unit 770 represents an area in which an actual frame is stored.

That is, the transmission frame structure according to the embodiment of the present invention includes a WLAN network card control area 710 for allowing the WLAN network card to reflect the frame transmission result, and a WLAN network card to efficiently transmit the frame. Frame configuration information control area 720 and the actual frame storage area 770.

Finally, when the RTS / CTS mechanism is to be used, the MAC address information area 750 is used in the area 770 where the actual frame is stored in order to reduce the trouble of analyzing the received MAC address. 760 transmits necessary information to the physical layer unit.

That is, in FIG. 3, the AC_BK queue 360 provides a frame connection list having a TID of 1 or 2 among the frames determined by the BA mechanism so that the frame is transmitted when a transmission opportunity is obtained by the queue transmission mechanism. In step 370, a frame association list having a TID of 0 among frames determined by the BA mechanism is provided so that the corresponding frame is transmitted when a transmission opportunity is obtained by the queue transmission mechanism.

The AC_VI queue 380 provides a frame association list with TIDs 3, 4, and 5 to transmit the corresponding frames, and the AC_VO queue 390 provides a frame association list with TIDs 6 or 7 so that the frames are transmitted. do.

In particular, the AC_VO queue 390 provides management frames (ADDBA Request, ADDBA Response, DELBA) and control frames (BlackAckReq, BlackAck) necessary to apply the BA mechanism so that the queue transmission mechanism can be applied first.

8 illustrates an STA (transmission) management queue management structure according to an embodiment of the present invention.

As shown in FIG. 8, the STA transmission queue management structure according to an embodiment of the present invention includes a destination address table 810, transmission queue table areas 820 and 830 for managing transmission queues for each TID, and actual transmissions to be made next. Transmission queue connection lists 840 and 850 for storing frames.

The destination address table 810 is composed of an index and a destination address (ADDR), and the index is for managing frames by dividing by TID according to the destination address. The TID tables 820 and 830 are for managing a connection list of frames corresponding to each TID.

The transmission queue connection lists 840 and 850 of the next frame to be transmitted are for managing a list to be linked with the association of the storage position (FID_PTR) information of the actual frame. In addition, the transmission queue connection list 840 of a transmission frame to be transmitted next includes position information, control information, and actual frame of transmission frame buffers that actually store one divided frame as shown in FIG. 7.

As described above, since a transmission frame according to an embodiment of the present invention has interconnection according to mutual position information of a frame composed of a plurality of information fields, it is possible to simply find a frame position to be transmitted next and increase transmission efficiency of the frame. .

In addition, the automatic gain control method of the OFDM system according to an embodiment of the present invention is implemented as a program to be stored in a computer-readable form on a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) Can be.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited thereto, and various other changes and modifications are possible.

As described above, according to the present invention, a wireless LAN apparatus for supporting EDCA BA can efficiently support the IEEE 802.11e standard by providing a queue structure for managing a wireless medium access control frame according to TID information.

Claims (20)

An apparatus for transmitting a WLAN medium access control frame for supporting EDCA (Enhanced Distribution Channel Access) block Ack (BA), A destination address table for managing TID (Traffic ID) information required for each destination address; A TID queue table that manages a frame connection list for each TID generated for each destination address, and classifies the generated transmission frame according to a TID when a frame to be transmitted from an upper logical link control layer to a WLAN network card is generated; A frame storage unit for storing transmission frames classified according to the TID; A frame forwarding unit for forwarding the transmission frame to a corresponding transmission queue according to a Block Ack (BA) mechanism; And Frame transfer unit for transmitting the frame using the interrupt register and the transfer request register WLAN medium access control frame transmission apparatus comprising a. delete The method of claim 1, The frame link list, A queue connection list to be transmitted next including location information in which actual frames are stored for each TID; And The currently connected queue connection list used when the list of frames determined to be transmitted by the BA mechanism is transmitted according to an access category and transmitted to the corresponding transmission queue. WLAN medium access control frame transmission apparatus comprising a. The method of claim 3, The queue connection list currently being transmitted is An AC_BK queue connection list for a background service; An AC_BE queue connection list for best effort services; An AC_VI queue connection list for video services; And AC_VO Queue Connection List for Voice Service WLAN medium access control frame transmission apparatus comprising a. The method of claim 1, The interrupt register, An interrupt information register for notifying the content of the interrupt; And An interrupt control register that enables or disables the interrupt WLAN medium access control frame transmission apparatus comprising a. The method of claim 1, The transfer request register, An AC_BK_TRQ register informing a request for transmission of a frame corresponding to the background service; An AC_BE_TRQ register informing a request for transmission of a frame corresponding to the best effort service; An AC_VI_TRQ register informing a request for transmission of a frame corresponding to the video service; And AC_VO_TRQ register indicating a request for transmission of a frame corresponding to the voice service WLAN medium access control frame transmission apparatus comprising a. The method according to any one of claims 1 to 6, The structure of the transport frame, A WLAN network card control area for allowing the WLAN network card to reflect a frame transmission result; A frame configuration information area for allowing a WLAN network card to efficiently transmit a frame; And Area of Management MAC Protocol Data Unit (MMPDU) or MAC Service Data Unit (MSDU) where actual transmitted frames are stored WLAN medium access control frame transmission apparatus comprising a. The method of claim 7, wherein The WLAN network card control area, A valid bit (V) indicating whether the frame is valid; And Transmission error bit (TE) indicating a transmission failure of the frame WLAN medium access control frame transmission apparatus comprising a. The method of claim 7, wherein The frame configuration information area is RC (RTS / CTS) bit indicating whether to send a Request to Send / Clear to Send (RTS / CTS) mechanism; A List End (LE) bit specifying the end of the frame list; An MSDU End (ME) bit indicating the end of the MSDU; An MSDU Begin (MB) bit indicating the start of an MSDU; And CE (Chunk End) bit indicating the discontinuity of the area where the frame is stored WLAN medium access control frame transmission apparatus comprising a. The method of claim 7, wherein The structure of the transport frame, A last MPDU location information area for efficiently handling transmission errors; A next MPDU location information area containing location information of a transport frame structure to be transmitted next to the current transport frame structure; A destination medium access control address information area for facilitating the RTS / CTS mechanism in accordance with the specification of the WLAN medium access control layer; And Transmission vector information area including information required for the physical layer portion WLAN medium access control frame transmission device further comprising. In the method for transmitting a WLAN medium access control frame for EDCA (Enhanced Distribution Channel Access) Block Ack (BA) support, a) generating a medium access control frame when a frame to be transmitted from the upper logical link control layer to the WLAN network card occurs; b) classifying and storing the media access control frame according to TID (Traffic ID) information of the media access control frame; c) constructing a new frame list to be transmitted next by referring to the corresponding transmission queue table according to the information of the queue transmission register; d) confirming a frame to be transmitted from the frame list according to a Block Ack (BA) mechanism, and notifying the WLAN network card of a request for transmission of the confirmed frame; And e) transmitting the frame using an interrupt register and a transfer request register. WLAN medium access control frame transmission method comprising a. delete The method of claim 11, Step d), When the frame to be transmitted is confirmed, the transmission request register value is set to 1 to inform the WLAN network card of the transmission request of the frame. WLAN medium access control frame transmission method. The method of claim 11, After step e), Receiving a frame transmission completion result of setting the transmission request register value to 0 from the WLAN network card; WLAN medium access control frame transmission method further comprising. The method according to any one of claims 11, 13 or 14, In step e), The WLAN network card determines whether to apply RTS / CTS (Request to Send / Clear to Send), the transmission interval, whether to increase or decrease the position of the frame, and whether to use the position information of the next MPDU with reference to the frame information. WLAN medium access control frame transmission method. The method of claim 11, In step e), When transmitting the last list of frames, the interrupt register indicates the request for transmission of a frame. WLAN medium access control frame transmission method. The method of claim 11, After step e), When the current frame transmission is completed, transmitting a frame requesting a transmission result through a queue for voice service according to the BA mechanism WLAN medium access control frame transmission method further comprising. The method of claim 11, In step e), In case of retransmission of the divided frame, if retransmission of the frame fails, it moves to the start position of the next MSDU using the last MSDU position information of the frame currently being transmitted. WLAN medium access control frame transmission method. delete The method of claim 11, Step d), Providing a frame connection list of the TID of 0 to a queue for a best effort service, Providing a frame association list having the TID of 1 or 2 to a queue for the background service, Providing a frame association list having the TID of 3, 4, or 5 to a queue for a video service, Providing a frame association list with the TID of 6 or 7 to the queue for the voice service. WLAN medium access control frame transmission method.

Images