CN100544294C - With less interFrameGap (IFS) time transmission Frame - Google Patents

Abstract

A kind of method that on data network, sends Frame, comprise that one sends the step of described Frame to receiver from transmitter with interFrameGap (IFS) time, this IFS time does not comprise that transmitter changes to the needed time of transmitter state from receiver state, has therefore improved efficiency of transmission widely.

Description

With less interFrameGap (IFS) time transmission Frame

Present patent application requires the U.S. Provisional Patent Application sequence number No.60/478 to submission on June 12nd, 2003, the U.S. Provisional Patent Application sequence number No.60/487 that on July 16th, 156 and 2003 submitted to, 694 priority, the disclosure of these patent applications integrally is being hereby incorporated by reference.

The present invention relates to data network transmission techniques, relate to the optimization method that is used for more effectively sending Frame particularly, wherein Frame sends with less interFrameGap (IFS) time on data network.

In transfer of data, ARQ (automatically re-send request may) agreement stipulates that each frame must be confirmed with ACK (affirmation) frame by receiver.Yet, because must waiting for, transmitter receives ACK before it sends next Frame, this has reduced the efficient of transfer of data.This also is like this at the radio data network that use is used for IEEE 802.11 agreements of MAC data frame transfer.In order to raise the efficiency, IEEE 802.11e has stipulated the no ACK strategy that wherein need not confirm frame, and the piece ACK strategy confirmed with single ACK frame by group of frame wherein.These new strategies have reduced frame overhead widely and have improved efficient.

And IEEE 802.11e has introduced the notion of transmission opportunity (TXOP).By this notion, the QSTA of non-AP (non-access some QoS strengthens the station) and QAP (access point that QoS strengthens) be the contention medium in time, in case they are linked into channel, they are just held channel and send a plurality of Frames with interFrameGap (IFS) time (this is SIFS (short IFS)) in by TXOP limit official hour.IEEB 802.11e regulation, during the TXOP limit, the QSTA/QAP of non-AP can use no ACK or piece ACK strategy.By no ACK strategy, each frame is sent out and does not expect ACK for this frame.If if the TXOP limit greater than the single frame transmission time and there is more frame just co-pending in the MAC formation, then each frame in succession can be sent out after the time at SIFS.Similarly, in piece ACK strategy, frame was sent by adjoining land with interFrameGap time SIFS before sending ACK by receiver.

Yet, this is not optimized aspect efficiency of transmission, need because the SIFS time in fact only will be returned to confirm to be only at the OSTA/QAP of the non-AP that receives, this is to add the turnaround time of receiver (RX) to transmitter (TX) because the described SIFS time comprises the time of processed frame.Under the situation of no ACK and piece ACK strategy, needn't allow receiver wait for that the SIFS time sends ACK frame (except must send ACK last frame in the piece ACK strategy of transmitter at receiver thereafter) again.

So, need a kind of method that in data network, more effectively sends Frame in the art with less interFrameGap (IFS) time.

According to the present invention, a kind of method that sends Frame on data network is provided, this method comprises that one sends the step of Frame to receiver from transmitter with interFrameGap (IFS) time.Transmitter receives only the piece ACK that a plurality of described Frames are confirmed, IFS does not comprise that transmitter changes to the needed time of transmitter state from receiver state.IFS includes only transmitter and detects the end of a frame and the needed time of beginning of next frame.Therefore, transmitter can send Frame continuously with the IFS that is shorter than SIFS, because this IFS does not comprise the described turnaround time.

Read the detailed description of the preferred embodiments of the present invention by the reference accompanying drawing, will clearer above and other characteristic of the present invention and advantage, wherein:

Fig. 1 shows that the IFS with interframe sends Frame; And

Fig. 2 shows that IFS is needed SIFS in the prior art.

As shown in Figure 1, Frame typically comprises physical layer control program (PLCP) expense and MAC Frame.The PLCP expense comprises a PLCP preamble 11 and a PLCP header 12.PLCP preamble 11 comprises and mainly being used in regularly and the information of synchronizing function, and PLCP header 12 mainly includes the information of length, transmission rate of pass frame or the like.The MAC Frame comprises: comprise mac header part 21, mac frame main part 22 and CRC (cyclic redundancy check (CRC)) part 23 of address information or the like, it is called as the frame control sequence (FCS) in the MAC layer.

When the Frame of the continuous sending order of transmitter during, between two sequence frames transmission, need interFrameGap (IFS) time to receiver.Traditionally, this IFS time can be with the same short at no ACK that is adopted by IEEE 802.11e and the SIFS under the piece ACK strategy (short IFS).As shown in Figure 2, SIFS comprises transmitter processes data frame (promptly detecting the end of a frame and the beginning of next frame) needed first time T 1, and second portion time T 2 (is transmitter changes to transmitter state from receiver state " turnaround time ".The SIFS time is a kind of waste under no ACK and piece ACK strategy, because transmitter did not need to receive the ACK from receiver before it can continue to send next Frame.

According to the present invention, under no ACK and piece ACK strategy, transmitter does not need to wait for that SIFS sends next Frame again.Particularly, do not need the frame of ACK to be sent out continuously immediately with IFS compared with the SIFS much shorter.More specifically, the IFS time does not need to comprise turnaround time T2 (when transmitter then needs this time T 2 when receiver state changes to transmitter state), and includes only the needed time T 1 of transmitter processes frame (promptly detecting the end of a frame and the beginning of next frame).So therefore Frame can improve efficiency of transmission widely with being sent out compared with the interFrameGap of SIFS much less.

Though more than described the preferred embodiments of the present invention in detail, it will be appreciated that under the condition that does not deviate from spirit of the present invention, those skilled in the art might make various changes, adaptive and modification.For example,, should see, the invention is not restricted to the environment of radio data network though preferred embodiment is to describe for the radio data network that uses IEEE 802.11 agreements of being revised by IEEE 802.11e draft standard.Therefore, protection scope of the present invention is only stipulated in appended claims.

Claims (5)

1. method that on data network, sends Frame, comprise with an interFrameGap time IFS and send described Frame to receiver from transmitter, wherein said transmitter receives only the piece ACK that a plurality of described Frames are confirmed, described IFS does not comprise that described transmitter changes to the needed time of transmitter state (T2) from receiver state.

2. the described method of claim 1, wherein said IFS includes only described transmitter and detects the end of a frame and the needed time of beginning (T1) of next frame.

3. the described method of claim 2, wherein said transmitter right and wrong QoS strengthens the access point (QAP) that station (non-QSTA) or QoS strengthen.

4. the described method of claim 1, wherein said data network is to use the radio data network of IEEE 802.11 agreements.

5. the described method of claim 4, wherein said IEEE 802.11 is made amendment by IEEE 802.11e draft standard.

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