CN103873479A - Parallel data transmission algorithm based on cross-layer estimation - Google Patents

Abstract

The invention provides a parallel data transmission algorithm based on cross-layer estimation. The parallel data transmission algorithm solves the problem that due to simple data dispatch, data packages are out of order when multiple paths of data are transmitted in parallel. The parallel data transmission algorithm comprises the steps that the RTT is obtained through a heartbeat mechanism and the activity of a path is judged; according to the effective signal-to-noise ratio of a data linkage layer and the rate and the bandwidth estimation value of a transmission layer, the path capacity is obtained and the path quality is determined by the activity of the path and the path capacity together. Data distribution dispatch is intelligently conducted according to the path quality. Package-loss reasons are judged according to the path capacity and different retransmission measures are taken. Double-information of the data linkage layer and the transmission layer can be sensed through the algorithm, more accurate and complete path quality estimation is obtained, efficient data distribution is conducted, and the phenomena that the data packages are out of order and are reordered are reduced. Meanwhile, the package-loss reasons are differentiated, so that an unnecessary congestion window is reduced. According to the parallel data transmission algorithm based on cross-layer estimation, the dynamic performance of a wireless network can be sensed and adapted to and the data transmission service with high quality is provided.

Description

A kind of panel data transmission algorithm based on cross-layer assessment

Technical field

The present invention relates to communication technique field, communication data transmission technology.Be specifically related to by cross-layer method, path quality to be assessed on SCTP and the realization of multipath parallel transmission based on path quality.

Background technology

Along with the development of the Internet and correlation technique, mobile device trends towards existing multiple network interfaces, has stronger computing capability, storage capacity and more advanced communication function simultaneously.In future, network will be supported multiple network access anywhere or anytime, and many hosts (Multihoming) technology is generally considered can apply these access devices, and multiplicity of network is provided.This makes multidiameter delay transmission CMT(ConcurrentMultipath Transfer) become the best way that improves performance for wireless communications.CMT can utilize multiple network interface multidiameter delay transmission data.Compared with single path, multipath has larger bandwidth, and mistake on certain paths can be recovered on another paths.The more important thing is, transmitting terminal can carry out data dispatch and congested balance between mulitpath, improves to greatest extent the service quality QoS of network service and application.Generally speaking, in the parallel and distributed of wireless network, CMT has good bandwidth polymerizing power, fault-tolerance and load balance ability.

SCTP SCTP(Stream Control Transmission Protocol) be the transport layer protocol of a kind of new many host characteristics of support of IETF formulation, can in same association, support multiple IP address to realize multi-path transmission simultaneously.The intrinsic many host characteristics of SCTP make it in CMT realization, have very much prospect.Up to now, IETF has obtained some valuable progress on SCTP CMT, but also exists many important and be full of challenging need of work and carry out.In SCTP CMT, the problem that needs emphasis to consider is how deal with data reorders and packet loss.Because each path parameter exists larger otherness and dynamic, traditional circulation robin scheduling can cause buffer memory and block, and serious Out-of-sequence packets occurs in extra-heavy buffer memory and receive and reorder.For how distributing data reduce and reorder between multipath of decision-making, people have done a large amount of work, but great majority work is all that to send-receive based on exchanges data, monitoring be the connection parameter relying in transport layer alternately or only.Because time and the frequency variation characteristics of wireless link can not be reacted directly into transport layer, the information of the wireless connections that these mechanism are obtained is also imperfect, thereby may be inaccurate.

In addition, because wireless channel is very unreliable, thus often there is packet loss, and reset and obscure with packet.In wireless environment, packet loss is often caused by wireless mistake, if be inappropriate by it according to congested processing according to the original design of SCTP/TCP.If repeat mistakenly the send window algorithm that reduces by half, the performance of CMT can reduce thus.Therefore, differentiate packet loss and cause because of congested or wireless mistake on earth, it is very important then taking different packet loss corresponding measures.Obviously,, due to the ignorant to physical layer and data link layer, transport layer can not accurately judge packet loss reason.

Summary of the invention---claims part

In view of this, the present invention proposes a kind of panel data transmission algorithm based on cross-layer assessment, in the multidiameter delay transmitting procedure of SCTP, according to the information acquisition path quality of transport layer and data link layer, according to path quality priority intelligence distribution transmission data, provide high performance data transport service.The present invention has designed an effective signal-to-noise ratio computing module and a speed & Bandwidth estimation module, obtain respectively the information of data link layer and transport layer, adopt a path quality assessment models based on cross-layer cooperation to judge path quality, design a panel data distribution algorithms based on path quality and carried out Data dissemination, finally proposed a perception re-transmission policy and carried out retransmission process.The present invention can assess path quality effectively, carries out intelligently Data dissemination scheduling, adapts to the dynamic of wireless network, for mobile subscriber provides effective multimedia transmission.

1, the panel data transmission algorithm based on cross-layer assessment, its step comprises:

A) path activity judgement.Utilize HEARTBEAT mechanism measuring route activity;

B) effective signal-to-noise ratio ESNR calculates.In data link layer, the frame that needs are retransmitted counts to get FER, calculates BER by FER, obtains ESNR according to the relation of BER-SNR;

C) speed & bandwidth estimation.Time mean speed value is estimated the situation that takies of way to acquire resource, real-time bandwidth estimated value track path real-time change situation;

D) the panel data distribution policy based on path quality.A path quality assessment models based on cross-layer cooperation, utilizes cross-layer gain of parameter path residual capacity, according to path capacity, path data distribution priority, pathway list SL is set; A panel data distribution algorithms based on path quality, according to the order of path list SL, distributes appropriate data successively to path according to the residual capacity of every paths, data total amount is subject to window limit;

E) perception re-transmission policy.Analyze packet loss reason according to path residual capacity, for taking respectively different retransmission algorithm by wireless error code and the congested packet loss causing.

2, path as claimed in claim 1 activity judgement, is characterized in that:

A) for every paths arranges the interval u of dynamic estimation, relatively u and RTO time judge path activity;

B) send two HEARTBEAT chunks detective paths, retransmit and exceed maximum retransmission if occur, it is inactive that path is set; If successfully receive two ACK, it is movable that path is set; Occur retransmit but receive two ACK, also allow data allocations even if path is inertia.

3, effective signal-to-noise ratio ESNR as claimed in claim 1 calculates, and it is characterized in that:

A), in data link layer, the frame flag that needs are retransmitted is error_frame, and error_frame is counted, and by recording the wrong frame of surveying range and the frame of all transmissions, can obtain FER.Utilize individual bit model to obtain BER by FER, finally obtain ESNR according to the relation of BER-SNR.

4, speed & bandwidth estimation as claimed in claim 1, is characterized in that:

A) the utilization data volume that success sends in estimation interval and these data take the total time of buffer memory, obtain the average transmission rate R in path in an estimation interval _e.The ratio value representation of average data packet length and on average enter-time departure for available bandwidth, the time moving average filter of utilization obtains bandwidth sample, then by predict-checking treatment of Kalman filter, obtains bandwidth estimation value BW _e.

5, the panel data distribution policy based on path quality as claimed in claim 1, is characterized in that:

A) the path quality assessment models based on cross-layer cooperation: by cross-layer parameter effective signal-to-noise ratio ESNR, average transmission rate R _ewith estimation of available bandwidth value BW _ecalculate path residue active volume, according to path capacity, Data dissemination priority is set, pathway list SL;

B) the panel data distribution algorithms based on path quality: according to the order of path list SL, distribute successively appropriate data, path residual capacity R to path according to the residual capacity of every paths _cfor on the occasion of time, the data volume of distribution can be on the basis of current congestion window increases in right amount, otherwise, conservatively according to window value distributing data.The total amount that sends data is subject to window limit.

6, perception re-transmission policy as claimed in claim 1, is characterized in that:

A) in the time that quick transmission arrives packet loss, transmitting terminal is according to path residual capacity R _cpacket loss reason is judged, if its value packet loss that wireless mistake causes for canonical is judged as is only adjusted threshold value; Otherwise be judged as congestion packet loss, when adjusting threshold value, reduce congestion window.

B), in the time that overtime transmission arrives packet loss, adopt the retransmission processing method of the SCTP of standard to carry out congestion window and threshold value adjustment.

The present invention has following technique effect:

1, in the present invention, data link layer is periodically to transport layer report ESNR information.Measure ESNR by FER, step is simple and convenient, the inaccuracy of bringing because not processing the problem of cochannel interference, the impact of signal multichannel, frequency selective fading and different frame size during the direct SNR having solved in reality measures.This ESNR has gathered the various factors in wireless transmission, and complicated radio communication is simplified, and can react well the route conditions of radio communication to upper strata.

2, in the present invention, transport layer has been carried out dual cognition to path status.One is rate estimates, provides an average transmission rate value in relatively long-term path, response path occupation condition; One is bandwidth estimation, has represented the real-time transmission rate of every paths, the real-time change situation of response path.Dual cognition can obtain the clear cognition to path status, for the decision-making of transport layer provides effective information.

3, in the present invention, utilize cross-layer parameter effective signal-to-noise ratio ESNR, average transmission rate R _ewith estimation of available bandwidth value BW _eobtain the integrated information in path, path quality is assessed.Cross-layer approach to cooperation can obtain the information of complete wireless connections, for panel data distribution algorithms provides perfect path quality assessment, makes path obtain efficient and rational application, reduces data rearrangement and packet loss because Data dissemination algorithm causes improperly.

Brief description of the drawings

Fig. 1 is the general frame of panel data transmission algorithm of the present invention;

Fig. 2 is path activity evaluation algorithm flow chart;

Fig. 3 is path bandwidth algorithm for estimating flow chart;

Fig. 4 is Data dissemination algorithm flow chart;

Fig. 5 is perception re-transmission policy algorithm flow chart;

Embodiment

For making technological means of the present invention, creation characteristic, reach object and effect is convenient to understand, the present invention will be described in detail below in conjunction with the accompanying drawings and the specific embodiments.

1, entire system frame diagram

In order to solve in SCTP CMT, due to data reordering and packet loss problem that the diversity in path produces, the present invention proposes a kind of panel data transmission algorithm based on cross-layer assessment.As shown in Figure 1, be entire system framework of the present invention, comprise transmitting terminal, the multipath on receiving terminal and wireless network.SCTP receiving terminal receives the data of sending from transmitting terminal, then feeds back accepting state.SCTP transmitting terminal is collected feedback, by the state of transport layer and the information acquisition path quality of data link layer, according to path quality distribution transmission data.

Cross-layer assessment models is utilized effective signal-to-noise ratio ESNR, and rate estimates value and bandwidth estimation value judge path capacity, sends HEARTBEAT and judges path activity, and both form path quality.The parameter that panel data distribution scheduling utilizes cross-layer assessment models to obtain, carries out Data dissemination according to the order of sequence and by volume.Packet loss is by the processing of perception re-transmission policy.

2, path activity judgement

In cross-layer cooperation, matter of utmost importance is need to how long calculate an ESNR and upgrade path quality.For every paths is provided with the interval u of a dynamic estimation.In the time there is packet loss, utilize confidential interval to obtain an interval sample x _k.

$\mathrm{Pr}\{\stackrel{\&OverBar;}{X}-Z_{1-\mathrm{\&epsiv;}/2}\&CenterDot;\frac{\mathrm{\&sigma;}}{\sqrt{N}}<u<\stackrel{\&OverBar;}{X}+Z_{1-\mathrm{\&epsiv;}/2}\&CenterDot;\frac{\mathrm{\&sigma;}}{\sqrt{N}}\}=1-\mathrm{\&epsiv;}---\left(1\right)$

Wherein for mean value, σ is standard deviation, Z _1-ε/2for a function of ε, in the time that previous estimation interval completes, choose the value of lower bound renewal u.

$u=\stackrel{\&OverBar;}{X}-Z_{1-\mathrm{\&epsiv;}/2}\&CenterDot;\frac{\mathrm{\&sigma;}}{\sqrt{N}}---\left(2\right)$

Estimation interval is relevant with path activity: after upgrading u, if certain paths has u≤RTO, packet loss often occurs, this path is set to inactive; Otherwise it is movable that path is set to.This two states is the same with the definition in standard SCTP.

But this algorithm has weak point.Because u is a statistics based on historical sample, transmitting terminal can only be known the long-term behaviour in path.If path burst fluctuation, can not ensure that this path activity performance promptly changes Data dissemination.Moreover SCTP CMT allows to reply SACK on other path, traditional RTT metering system may bring wrong time delay to estimate, so just can not be used for the assessment of path quality.Here, we do not adopt the RTT metering system of DATA chunks.Because HEARTBEAT_ACK must reply on the path identical with HEARTBEAT, the RTT time that we extract HEATBEAT chunks is as being RTT with reference to RTT _ref.

In order to obtain path activity and RTT accurately _ref, we change the fixing HEARTBEAT interval of SCTP into dynamic u.In the beginning of each estimation interval, transmitting terminal sends two HEARTBEAT chunks and carrys out detective path.If corresponding two HEARTBEAT_ACK have been replied in path within a RTO time, just remove error counter, even now u≤RTO also path is put can distribute data.Otherwise error counter counting, retransmits HEARTBEAT simultaneously.In the time that counter arrives Path.Max.Retrans, path is set to inactive.In the time that transmitting terminal successfully receives two HEARTBEAT_ACK, access time, shorter RTT was as RTT _ref.Finally, we can obtain the available active path of n bar, and process below all must not be participated in all inactive paths.

Fig. 2 is the flow chart of this algorithm, and its step is as follows:

1) judge path activity according to u: if path is set to inactive by u≤RTO, otherwise be set to active.

2) send two HEARTBEATS, start respectively the timer of two HEARTBEATS, path is set to can not distribute data, records the counter HBcount zero setting that successfully receives HEARTBEAT_ACK number.

3) if the value of counter HBcount is less than 2, carry out step 4, otherwise, forward step 6 to.

4) for the HEARTBEATS of each transmission, if successfully receive HEARTBEAT_ACK, record the RTT time, counter HBcount adds 1, and stops corresponding timer; If timer expired, retransmits HEARTBEAT, timer reclocking, time-out count device error adds 1.

5) if the value of counter error is greater than path maximum retransmission, path is set to inactive, proceed to step 6.Otherwise get back to step 3.

6) if the value of counter HBcount is 2, successfully receive two HEARTBEAT_ACK, carry out step 7, otherwise algorithm finishes.

7) if now path status is not mobilizable and the value of error counter is 0, do not occur that HEARTBEAT is overtime, it is movable path status to be changed into.

8) path being set to can distribute data, time-out count device error zero clearing, and selecting the shorter RTT time is RTT _ref.Algorithm finishes.

3, effective signal-to-noise ratio ESNR calculates

Due to dissimilar noise, decline and interference, wireless channel has unpredictability and unreliability.Conventionally, SNR can provide the comprehensive assessment of a radio communication.But in actual SNR measures, existing equipment is preorder and the head measurement of a PLCP in physical layer all, does not consider the Frame that speed is higher.Moreover the SNR of this direct report can not process cochannel interference, the impact of signal multichannel, frequency selective fading and different frame size.So we take the concept of ESNR to solve the deficiency of direct report SNR.

In specific radio communication, between BER and SNR, there is known definite one-one relationship.Suppose in current environment, BER=F (SNR), ESNR is defined as:

ESNR=F ^-1(BER) （3）

Calculate SNR and can transfer measurement BER to.The direct measurement meeting of BER brings very large expense in physical layer, so select to utilize the FER of data link layer to calculate BER.In an estimation interval u, frame and the FER of record transmission are very easily.In data link layer, once a Frame requires to retransmit, be just error_frame by this frame flag.By recording the frame of error_frame and all transmissions, can obtain FER:

$\mathrm{FER}=\frac{\mathrm{error}\_\mathrm{frame}\_\mathrm{num}}{\mathrm{rotal}\_\mathrm{frame}\_\mathrm{num}}---\left(4\right)$

Here, error_frame_num is the quantity of error_frame in an estimation interval, and total_frame_num is the quantity of the frame that altogether sends in an estimation interval.If there is the FER=0 in path, the FER in this path is set to rational minimum value.When all bits of an and if only if frame are all successfully decoded, a frame is just counted as merit and receives, so BER can be obtained by following formula:

Here, L is the byte number of a Frame.By formula (3), can calculate ESNR again.

4, speed & bandwidth estimation

In the time carrying out the processing of SCTP exchanges data, there are some data transmitting and taking path resource.We adopt a time mean speed to estimate to come the situation that takies of apprizing system path resource.Definition R _eaverage transmission rate for path in an estimation interval:

$R_e=\frac{\mathrm{sendsize}}{T_l-T_e}---\left(6\right)$

Here, sendsize is the data volume that success sends in estimation interval, T _ethe time of first data access path buffer memory, T _lit is the time that last data is left buffer memory.

Change the viewpoint of bandwidth estimation into transmission duration, that is: available bandwidth equals the ratio of average data packet length and on average enter-time departure.For the cancellation fluctuation that transmission behavior causes at random, bandwidth sample must do smoothing processing by first elapsed time average filter.Recycling Kalman filter obtains bandwidth estimation value.Kalman filter is a discrete time recursion filter, first carries out time renewal, by the current bandwidth status of former prediction of result; Measure again renewal, bring new sample into prior estimate, obtain posteriority and estimate.

As shown in Figure 3, the algorithm flow of estimating for path bandwidth:

1) obtain data length sample and time samples.

2) send data.Record sends the time of final data.

3) upgrade average data length and average length of time, calculate bandwidth sample.

4) carry out time renewal, obtain the priori estimates of bandwidth and error variance.

5) measure renewal, obtain the posterior estimate of bandwidth and error variance according to bandwidth sample.

5, the panel data distribution policy based on path quality

A) the path quality assessment models based on cross-layer cooperation

Be chosen in distributing data in another one cycle dynamics.Like this, cross-layer assessment and Data dissemination can carry out but with different step combinations simultaneously.Distribution cycle P _ddisposal ability dynamical correlation with each path.The processing time of one paths is:

$T_{\mathrm{handle}}=\frac{\mathrm{cwnd}}{B{W}_e}---\left(7\right)$

In order to make full use of all active paths, P _dcan select the maximum processing time:

$P_d=\max ({\mathrm{<figure-callout\; id="1"\; label="T\; handle"\; filenames="HDA0000484229150000031.png"\; state="\{\{state\}\}">T</figure-callout>}}_{{\mathrm{handle}}_{}},T_{{\mathrm{handle}}_2},T_{{\mathrm{handle}}_n})---\left(8\right)$

Afterwards, data will be at P _din time, be distributed in all path candidates simultaneously.In fixed environment, distribution frequency is:

Path capacity C can obtain by cross-layer mode:

C=BW _e·log ₂(1+ESNR) （9）

Due to a paths occupied R _e, the residual capacity R in this path _cfor:

R _c=C-R _e （10）

Then, by all path candidates according to R _cdescending, forms a path list SL new and classification.This makes R _clarger path has the higher-priority of Data dissemination.

At distribution interval P _din, the maximum data volume D that can distribute _maxlimited by following formula:

$D_{\max }=\min \begin{array}{c}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}({\mathrm{cwnd}}_i-{\mathrm{outs}\tan \mathrm{ding}}_i)\\ a\_\mathrm{rwnd}-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{outs}\tan \mathrm{din}{g}_i\end{array}---\left(11\right)$

B) the panel data distribution algorithms based on path quality

According to the queue sequence of SL, successively according to the R of every paths _cdistribute appropriate data to path.If R _cfor on the occasion of, represent that this path has potential disposal ability to increase its throughput, the data volume of distribution is current cwnd and adds some R _c.Otherwise only conservatively distributing data is the difference of cwnd and outstanding.At this cycle P _din, as long as cwnd allows, the data volume D of distribution can move closer to D _max.If data allocations amount has reached D _max, completed the Data dissemination task in this cycle and stopped immediately Data dissemination.Wait for this end cycle, then recalculate T _handlewith next P _d.Upgrade C and R _c, at next P _drepeating algorithm continues the distribution of data.

As shown in Figure 4, be the flow process of Data dissemination algorithm:

1) for path i in list SL, if R _cbe greater than zero, by formula (11), distributing data amount D be set, otherwise, according to formula (12), distributing data amount is set and is:

2) calculate the data D having distributed _total=D _total+ i.D.

3) if D _total≤ D _max, in the time that cwnd allows on the i of path distributing data i.D; If D _total>D _max, stop data allocations, wait for the next Data dissemination time.

4), for next paths, repeating step 1-3, until distribute all paths.

6, perception re-transmission policy

If there is packet loss in exchanges data, can analyze the reason that causes packet loss according to Rc.And adopt different steps to recover packet loss.

In the time that quick transmission arrives packet loss, transmitting terminal can judge packet loss reason: if R _c>0 represents that this path does not reach Congestion Level SPCC, and packet loss is attributed to wireless error code, adjusts ssthresh but does not adjust cwnd:

ssthresh=max(R _eRTT _ref,cwnd/2,4MTU) （13）

Wherein R _ethe result of rate estimates, RTT _refpreviously described reference RTT.We adopt the rate estimates value in cycle is random and burst because of wireless error code, and its adjustment need to come back to average level.Otherwise, R _c<0, path is by excessive use, packet loss ascribed to congested, adjusts cwnd when adjusting ssthresh:

ssthresh=max(BW _eRTT _ref,cwnd/2,4MTU) （14）

cwnd＝min(cwnd,ssthresh) （15）

Wherein BW _efor bandwidth estimation value.We adopt real-time bandwidth estimation value to be because congested representative connects variation in essence.

For overtime re-transmission, because RTO is a relatively long time, there is serious congested or wireless mistake overtime indication of T3-rtx timer, and we only conservatively adopt the treating method of standard SCTP.

After adjustment, choose and have the path of maximum cwnd and the packet of retransmission of lost as quickly as possible.Fig. 5 is the flow process of retransmission algorithm.

Claims (6)

1. the panel data transmission algorithm based on cross-layer assessment, its step comprises:

A) path activity judgement.Utilize HEARTBEAT mechanism measuring route activity;

B) effective signal-to-noise ratio ESNR calculates.In data link layer, the frame that needs are retransmitted counts to get FER, calculates BER by FER, obtains ESNR according to the relation of BER-SNR;

C) speed & bandwidth estimation.Time mean speed value is estimated the situation that takies of way to acquire resource, real-time bandwidth estimated value track path real-time change situation;

D) the panel data distribution policy based on path quality.A path quality assessment models based on cross-layer cooperation, utilizes cross-layer gain of parameter path residual capacity, according to path capacity, path data distribution priority, pathway list SL is set; A panel data distribution algorithms based on path quality, according to the order of path list SL, distributes appropriate data successively to path according to the residual capacity of every paths, data total amount is subject to window limit;

E) perception re-transmission policy.Analyze packet loss reason according to path residual capacity, for taking respectively different retransmission algorithm by wireless error code and the congested packet loss causing.

2. path as claimed in claim 1 activity judgement, is characterized in that:

A) for every paths arranges the interval u of dynamic estimation, relatively u and RTO time judge path activity;

B) send two HEARTBEAT chunks detective paths, retransmit and exceed maximum retransmission if occur, it is inactive that path is set; If successfully receive two ACK, it is movable that path is set; Occur retransmit but receive two ACK, also allow data allocations even if path is inertia.

3. effective signal-to-noise ratio ESNR as claimed in claim 1 calculates, and it is characterized in that:

A), in data link layer, the frame flag that needs are retransmitted is error_frame, and error_frame is counted, and by recording the wrong frame of surveying range and the frame of all transmissions, can obtain FER.Utilize individual bit model to obtain BER by FER, finally obtain ESNR according to the relation of BER-SNR.

4. speed & bandwidth estimation as claimed in claim 1, is characterized in that:

A) the utilization data volume that success sends in estimation interval and these data take the total time of buffer memory, obtain the average transmission rate R in path in an estimation interval _e.The ratio value representation of average data packet length and on average enter-time departure for available bandwidth, the time moving average filter of utilization obtains bandwidth sample, then by predict-checking treatment of Kalman filter, obtains bandwidth estimation value BW _e.

5. the panel data distribution policy based on path quality as claimed in claim 1, is characterized in that:

A) the path quality assessment models based on cross-layer cooperation: by cross-layer parameter effective signal-to-noise ratio ESNR, average transmission rate R _ewith estimation of available bandwidth value BW _ecalculate path residue active volume, according to path capacity, Data dissemination priority is set, pathway list SL;

B) the panel data distribution algorithms based on path quality: according to the order of path list SL, distribute successively appropriate data, path residual capacity R to path according to the residual capacity of every paths _cfor on the occasion of time, the data volume of distribution can be on the basis of current congestion window increases in right amount, otherwise, conservatively according to window value distributing data.The total amount that sends data is subject to window limit.

6. perception re-transmission policy as claimed in claim 1, is characterized in that:

A) in the time that quick transmission arrives packet loss, transmitting terminal is according to path residual capacity R _cpacket loss reason is judged, if its value packet loss that wireless mistake causes for canonical is judged as is only adjusted threshold value; Otherwise be judged as congestion packet loss, when adjusting threshold value, reduce congestion window.

B), in the time that overtime transmission arrives packet loss, adopt the retransmission processing method of the SCTP of standard to carry out congestion window and threshold value adjustment.

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