CN102685468A - Method and device for transmitting video packets - Google Patents

Abstract

The invention provides a method and a device for transmitting video packets. The method includes the steps: determining the priority level of the video packets and estimating transmission delay of the video packets; distributing counters for the video packets and determining initial values of the counters according to the priority level of the video packets and/or the transmission delay of the video packets; and transmitting the video packets according to count values of the counters and adjusting count values corresponding to the video packets which are not transmitted. By the aid of the method and the device, more important video packets in video data can be ensured, so that video transmission quality is improved.

Description

The transmission method of video packets and equipment

Technical field

The present invention relates to wireless communication technology, relate in particular to a kind of transmission method and equipment of video packets.

Background technology

WLAN (Wireless Local Area network; WLAN) adopt distributed coordination function (Distributed Coordination Function usually; DCF) agreement; According to the DCF agreement, each node in the network is avoided (Carrier Sense Multiple Access with Collision Avoidance, the competitive access wireless channel of mode CSMA/CA) with the access/conflict of carrier sense multiple spot.The flow process of competitive access wireless channel roughly comprises: when node has data to send, at first carry out channel and intercept, if channel idle, (Distributed Interframe Space DIFS) sends data after time then to wait for the distributed frame spacing; If channel busy then starts backoff counter, the initial value of backoff counter is a value of getting at random on interval [0, W], and W is called as competition window, and the value of W is dynamically to change the min-window value W of in-system define _MinWith max-window value W _MaxBetween.Continue to intercept channel afterwards, whenever listen to channel idle one time, then the value of backoff counter subtracts one, if listen to channel busy then keep the value of backoff counter constant.When the value of backoff counter is kept to 0, show this node competition success, begin to send data.

In wlan network, in order to support that (Quality of Service, QoS) demand have proposed the enhancing distributed channel and inserted (Enhanced Distributed Channel Access, EDCA) agreement the real-time service quality of using.(Access Category AC), is respectively AC_VO, AC_VI, AC_BE and AC_BK to have introduced the access style of 4 different priorities in the EDCA agreement.Different AC adopts different access parameters, and access parameter for example comprises min-window value W _MinWith max-window value W _Max

When adopting wlan network transmission of video bag, can calculate the probability of every type video packets in the prior art, the probable value according to dynamic calculation obtains is mapped to video packets in the different AC formations.But; This mode can not embody the character of video packets itself, can not guarantee that important video packets preferentially is transmitted, and the video packets that for example priority is high is not necessarily by preferential transmission; Perhaps possibly send the video packets that exceeds delay requirement, thereby reduce the quality of video transmission.

Summary of the invention

The embodiment of the invention provides a kind of transmission method and equipment of video packets, in order to improve the quality of video transmission.

The embodiment of the invention provides a kind of transmission method of video packets, comprising:

Confirm the priority of video packets, and the transmission delay of estimation video packets;

For video packets is distributed counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets;

According to the count value transmission of video bag of said counter, and adjust the corresponding count value of not transmitting of video packets.

The embodiment of the invention provides a kind of transmission equipment of video packets, comprising:

Determination module is used for confirming the priority of video packets and the transmission delay of estimation video packets;

The counter distribution module is used to video packets and distributes counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets;

Processing module is used for the count value transmission of video bag according to said counter, and adjusts the corresponding count value of video packets of not transmission.

Can know by technique scheme; The embodiment of the invention is through distributing counter for video packets; And the priority of count value and video packets and/or the transmission delay of video packets are relevant; Can be implemented in the preferential high video packets of priority of sending in the transmission course of video packets, perhaps preferential the transmission is about to overtime video packets, thereby improves the quality of video transmission.

Description of drawings

Fig. 1 is the schematic flow sheet of transmission method one embodiment of video packets of the present invention;

Fig. 2 is the schematic flow sheet of another embodiment of transmission method of video packets of the present invention;

Fig. 3 is the schematic flow sheet of another embodiment of transmission method of video packets of the present invention;

Fig. 4 is the structural representation of transmission equipment one embodiment of video packets of the present invention;

Fig. 5 is the structural representation of another embodiment of transmission equipment of video packets of the present invention.

Embodiment

Fig. 1 is the schematic flow sheet of transmission method one embodiment of video packets of the present invention, comprising:

Step 11: confirm the priority of video packets, and the transmission delay of estimation video packets;

Wherein, in the video transmission process, dissimilar video packets has different significance levels, for example, can video packets be divided into according to importance order from high to low: I-frame video bag, P frame video packets and B frame video packets.Therefore, the priority that can preestablish the I-frame video bag is the highest, is P frame video packets secondly, is B frame video packets at last.

It is understandable that, under the scene of not distinguishing I-frame video bag, P frame video packets and B frame video packets, also can adopt other dividing mode, and be every type video packets definition corresponding priorities.

The transmission delay of video packets can be set the transmission delay of the video packets of number according to the front of the character of the communication media of physical layer and current video bag, and estimation obtains, and the character of the communication media of physical layer for example is propagation rate, propagation delay etc.

Step 12: for video packets is distributed counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets;

Wherein, this initial value can with priority and/or the transmission delay relation of being inversely proportional to, promptly the priority of video packets transmission delay high more and/or estimation is big more, this initial value is just more little.Perhaps, optional, the initial value of count value also can be proportional with priority and/or transmission delay, and promptly the priority of video packets transmission delay high more or estimation is big more, and this initial value is just big more.

Step 13:, and adjust the corresponding count value of not transmitting of video packets according to the count value transmission of video bag of said counter.

For example, if initial value and priority and/or the transmission delay relation of being inversely proportional to is so preferentially sent the little video packets of count value, and after sending video packets, the count value that the video packets of not sending is corresponding reduces 1.Perhaps, if initial value and priority and/or transmission delay are proportional, the so preferential big video packets of transmitting counter, and after sending video packets, the count value that the video packets of not sending is corresponding increases by 1.

Optional, before distributing counter, can judge at first whether video packets is overtime for video packets; For example, during less than the delay requirement set, show not overtime at the transmission delay of estimation; Otherwise overtime for, when video packets is carried out follow-up operations such as distribution counter again after not overtime.

In the present embodiment,, so just should preferentially send the high video packets of priority because the high more video packets that shows of priority of video packets is important more; In addition, because the transmission delay of the video packets of estimation is big more, just show that this video packets is more approaching overtime, in order to satisfy the demand of low delay, this video packets just needs to be transmitted the soonest so.According to priority and/or transmission delay count value is set in the present embodiment, and, can guarantees the prioritised transmission of the high perhaps video packets that transmission delay is big of priority, thereby improve video transmission quality according to count value transmission of video bag.

Further, referring to Fig. 2, the present invention provides another kind of embodiment, and this embodiment can avoid the collision between the video packets as far as possible.

Described in background technology, when the value of backoff counter was kept to 0, node just can send data.So, if there is the backoff counter of two or more nodes to reduce to 0 simultaneously, these nodes will send data simultaneously, and channel will bump this moment, and node can't correctly receive data.After detecting collision, sending node begins retransmission processes, and this node increases the value of competition window, and gets into backoff procedure again.If number of retransmissions surpasses the maximum of system's regulation, then abandon this bag, get into the process of transmitting of next packet.

In addition, the window value of different AC formations is different, and is specific as follows: W _Min[AC_VO]=7, W _Max[AC_VO]=15; W _Min[AC_VI]=15, W _Max[AC_VI]=31; W _Min[AC_BE]=31, W _Max[AC_BE]=1023; W _Min[AC_BK]=31, W _Max[AC_BK]=1023.

Because the W of AC_VO and AC_VI _MinAnd W _MaxBetween spacing less, will more be prone to bump for the video packets in AC_VO and these two formations of AC_VI so.

In order to reduce collision probability, present embodiment comprises:

Step 21: different video packets is assigned in the different AC formations.

Wherein, video packets can be divided into according to importance: I-frame video bag, P frame video packets and B frame video packets, the I-frame video bag is most important, is P frame video packets secondly, is B frame video packets at last.

So, can I-frame video bag and P frame video packets be assigned in the AC formation of higher priority, for example be assigned in the AC_VI formation; B frame video packets is assigned in the AC formation of lower priority, for example is assigned in the AC_BE formation.

Optional; Because in some agreements; Video packets can not be divided into I-frame video bag, P frame video packets and B frame video packets, so can be according to the priority AC formation of video packets, for example; The video packets of higher priority is assigned in the AC formation of higher priority, the video packets of lower priority is assigned in the AC formation of lower priority.

Step 22: the video packets in the AC formation of setting is transmitted according to count value.

Wherein, the AC formation of setting can be the higher AC formation of priority, for example, in the above-mentioned steps video packets is distributed to AC_VI formation and AC_BE formation respectively, and the AC formation of setting so just is meant the AC-VI formation.

Afterwards the video packets in this AC_VI formation is transmitted according to count value, idiographic flow can be referring to a last embodiment.

According to priority and/or transmission delay count value is set in the present embodiment, and, can guarantees the prioritised transmission of the high perhaps video packets that transmission delay is big of priority, thereby improve video transmission quality according to count value transmission of video bag.In addition; Present embodiment is through being assigned to different video packets in the different AC formations; A plurality of video user are arranged so simultaneously during transmitting video data; Can reduce the number of the video packets in the AC formation that is assigned to higher priority, and then can reduce the probability that conflicts in the network, improve the network effective throughput.

Fig. 3 is the schematic flow sheet of another embodiment of transmission method of video packets of the present invention, and present embodiment is an example video packets is distributed to AC_VI and AC-BE formation, and present embodiment comprises:

Step 31: for video packets is provided with priority.

For example, with the priority of prio (p) expression video packets p, the priority of video packets can be set to:

$\mathrm{prio}\left(p\right)=\left\{\begin{array}{cc}1,& I\\ 2,& P\\ 3,& B\end{array}\right.$

Following formula shows: the priority value of I-frame video bag is 1, and the priority value of P frame video packets is 2, and the priority value of B frame data bag is 3.

Afterwards, can in the packet header of video packets, carry the priority of video packets, for example, the network abstraction layer unit of video packets (Network Abstract Layer Unit NALU) carries in NRI (Nal_ref_dc) field of head, and occurrence can be expressed as:

$\mathrm{NRI}=\left\{\begin{array}{cc}00,& \mathrm{prio}\left(p\right)=3\\ 01,& \mathrm{prio}\left(p\right)=2\\ 10,& \mathrm{prio}\left(p\right)=1\end{array}\right.$

Following formula shows: priority value is that the value of the NRI field of 3 video packets is 00, and priority value is that the value of the NRI field of 2 video packets is 01, and priority value is that the value of the NRI field of 1 video packets is 10.

It is understandable that the value of the priority of above-mentioned setting and the value of NRI are a kind of example, also can adopt other modes that priority is set.

Step 32: the priority according to video packets is assigned to video packets in the corresponding queues.

For example, if prio (p)=3, the formation end of then this video packets being inserted AC_BE, otherwise the formation end of inserting AC_VI.

It is understandable that the AC formation that present embodiment distributes is a kind of example, also can be assigned in the AC formation of alternate manner.

According to the method for salary distribution of present embodiment, I-frame video bag and P frame video packets will be assigned in the AC_VI formation, and B frame data bag will be assigned in the AC_BE formation.

Step 33: the transmission delay of video packets in the estimation AC_VI formation.

Computing formula can be following: ${\hat{E}}_L=\frac{E_{L,\mathrm{Min}}+E_{L,\mathrm{Max}}}{2}$

Wherein,

$E_{L,\min }=(1+\stackrel{\‾}{R})(\mathrm{\α}+{\mathrm{\β}}_{\min }+{\stackrel{\‾}{T}}_{\mathrm{pause}}\×L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\δ})$

$E_{L,\max }=(1+\stackrel{\‾}{R})(\mathrm{\α}+{\mathrm{\β}}_{\max }+{\stackrel{\‾}{T}}_{\mathrm{pause}}\×L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\δ})$

$\mathrm{\α}=\underset{j=1}{\overset{L}{\mathrm{\Σ}}}{T}_{j,\mathrm{trans}},$

$T_{j,\mathrm{trans}}=\mathrm{AIFS}[\mathrm{AC}\_\mathrm{VI}]+\frac{S_{j,\mathrm{data}}+S_{\mathrm{header}}}{\mathrm{\υ}}+\mathrm{\δ}+\mathrm{SIFS}+\mathrm{\δ}$

${\mathrm{\β}}_{\min }=\frac{\mathrm{aSlotTime}\×W_{\min }[\mathrm{AC}\_\mathrm{VI}]\×L}{2}$

${\mathrm{\β}}_{\max }=\frac{\mathrm{aSlotTime}\×W_{\max }[\mathrm{AC}\_\mathrm{VI}]\×L}{2}$

${\stackrel{\‾}{T}}_{\mathrm{pause}}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{t}_{-k,\mathrm{pause}}$

$\stackrel{\‾}{R}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{r}_{-k}$

$T_{\mathrm{ACK}}=\frac{S_{\mathrm{ACK}}}{\mathrm{\υ}}$

Wherein,

Transmission delay for estimation; S _{J, data}It is the size of j bag in the AC_VI formation; S _HeaderIt is the size of MAC layer header; S _ACKIt is the size of ACK bag; t _{-k, pause}K the guarantee for returns in front that is the video packets of current estimation kept away the break period in the process, and just backoff counter keeps the constant time of count value when listening to channel busy; r _-kIt is front k the bag number of retransmissions of the video packets of current estimation; υ is the transmission rate of physical layer; δ is the propagation delay of physical layer; M is the number of previous packet of the video packets of the current estimation of choosing set; AIFS [AC_VI]=2, aSlotTime are the DCF system time constants, and the carrier wave of channel detects and the data transmission is a basic time unit with this constant all.T in the above-mentioned parameter _{-k, pause}And r _-kThe transmission situation of front video packets that can be through statistics current video bag obtains, and all the other parameters are set point or agreement setting.

Step 34: after the video packets in the AC_VI formation is not overtime,, and the initial value of count value is set for video packets is distributed counter.

Wherein, Suppose that τ is the delay requirement of setting; When the transmission delay of estimation during less than τ; Showing not overtimely, otherwise is overtime.After video packets is overtime, can abandon this video packets.

The computing formula of the initial value that is provided with can for:

$c_0=\left\{\begin{array}{cc}0,& \mathrm{prio}\left(p\right)=2\\ \frac{2\&times;c_{\min }\&times;{\hat{E}}_L}{\mathrm{\&tau;}},& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L<\frac{\mathrm{\&tau;}}{2}\\ c_{\min },& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L\&GreaterEqual;\frac{\mathrm{\&tau;}}{2}\end{array}\right.$

And,

Wherein, τ is the delay requirement of setting;

F is a frame per second;

is the number that an average frame is divided into video packets;

N be a picture group (Group ofPicture, GOP) in the number of all frame of video;

N _pIt is the number of P frame among the GOP;

expression rounds up.

in the above-mentioned parameter can obtain through statistics, and all the other parameters are the value of agreement regulation or the value of setting.

Step 35: if the video packets of transmission AC_VI formation is then selected the minimum video packets transmission of count value c.

Wherein, in avoidance mechanism, node is that the count value in backoff counter is kept at 0 o'clock and shows and competes the channel right to use.Because the W that different AC formations is corresponding different _MinAnd W _Max, so corresponding each AC formation can be provided with a backoff counter, and the count value of the backoff counter which AC formation is corresponding is kept to 0 earlier, just shows the video packets that will transmit this AC formation.

Step 36: after video packets transmission, the count value of the remaining video bag of AC_VI in formation is subtracted one.

In addition, if the video packets of transmission AC_BE formation can be transmitted according to putting in order of video packets in the AC_BE formation.

Present embodiment can reduce the probability that conflicts in the network through the video packets of different priorities being distributed to different AC formations, improves the network effective throughput; Through in the AC_VI formation according to priority and transmission delay count value; And according to count value transmission of video bag; Can guarantee the prioritised transmission of important video packets, for example, the video packets that prioritised transmission priority is high; Perhaps prioritised transmission is more near the video packets of delay requirement, thereby improved the quality of video transmission.

Fig. 4 can be an equipment of carrying out said method for the structural representation of transmission equipment one embodiment of video packets of the present invention, this equipment, and this equipment comprises determination module 41, counter distribution module 42 and processing module 43; Determination module 41 is used for confirming the priority of video packets, and the transmission delay of estimation video packets; Counter distribution module 42 is used to video packets and distributes counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets; Processing module 43 is used for the count value transmission of video bag according to said counter, and adjusts the corresponding count value of video packets of not transmission.

Referring to Fig. 5, this equipment can also comprise: queue assignment module 44, be used for priority according to video packets, and the video packets of different priorities is assigned in the different AC formations.

Optional, said queue assignment module 44 specifically is used for the video packets with first priority is assigned to the AC_VI formation, and the video packets that will have second priority is assigned in the AC_BE formation, and wherein first priority is higher than second priority; Said determination module 41 specifically is used for the video packets estimation transmission delay to the AC_VI formation.

Optional, said determination module 41 specifically is used for: set the transmission situation of the video packets of number, the transmission delay of estimation video packets according to the front of the character of physical layer transmission media and the current video packets that will estimate.

Optional, said processing module 43 specifically is used for:

If the priority of the initial value of said counter and said video packets and/or the transmission delay of the said video packets relation of being inversely proportional to, the corresponding count value of the then little video packets of prioritised transmission count value, and the video packets that will not transmit subtracts 1; Perhaps,

If the priority of the initial value of said counter and said video packets and/or the transmission delay of said video packets are proportional, the corresponding count value of the then big video packets of prioritised transmission count value, and the video packets that will not transmit adds 1.

Optional, the computing formula of the transmission delay of said determination module 41 estimation video packets is:

${\hat{E}}_L=\frac{E_{L,\min }+E_{L,\max }}{2},$

Wherein,

$E_{L,\min }=(1+\stackrel{\&OverBar;}{R})(\mathrm{\&alpha;}+{\mathrm{\&beta;}}_{\min }+{\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}\&times;L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\&delta;}),$

$E_{L,\max }=(1+\stackrel{\&OverBar;}{R})(\mathrm{\&alpha;}+{\mathrm{\&beta;}}_{\max }+{\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}\&times;L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\&delta;}),$

$\mathrm{\&alpha;}=\underset{j=1}{\overset{L}{\mathrm{\&Sigma;}}}{T}_{j,\mathrm{trans}},$

$T_{j,\mathrm{trans}}=\mathrm{AIFS}[\mathrm{AC}\_\mathrm{VI}]+\frac{S_{j,\mathrm{data}}+S_{\mathrm{header}}}{\mathrm{\&upsi;}}+\mathrm{\&delta;}+\mathrm{SIFS}+\mathrm{\&delta;},$

${\mathrm{\&beta;}}_{\min }=\frac{\mathrm{aSlotTime}\&times;W_{\min }[\mathrm{AC}\_\mathrm{VI}]\&times;L}{2},$

${\mathrm{\&beta;}}_{\max }=\frac{\mathrm{aSlotTime}\&times;W_{\max }[\mathrm{AC}\_\mathrm{VI}]\&times;L}{2},$

${\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}{t}_{-k,\mathrm{pause}},$

$\stackrel{\&OverBar;}{R}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}{r}_{-k},$

$T_{\mathrm{ACK}}=\frac{S_{\mathrm{ACK}}}{\mathrm{\&upsi;}},$

Wherein, Transmission delay for estimation; S _{J, data}It is the size of j bag in the AC_VI formation; S _HeaderIt is the size of MAC layer header; S _ACKIt is the size of ACK bag; t _{-k, pause}K the guarantee for returns in front that is the video packets of current estimation kept away the break period in the process, and just backoff counter keeps the constant time of count value when listening to channel busy; r _-kIt is front k the bag number of retransmissions of the video packets of current estimation; υ is the transmission rate of physical layer; δ is the propagation delay of physical layer; M is the number of previous packet of the video packets of the current estimation of choosing set; AIFS [AC_VI]=2, aSlotTime are the DCF system time constants.

Optional, said video packets with first priority comprises that priority is that 1 video packets and priority are 2 video packets, and the computing formula of the initial value of the counter of said module assigns is:

$c_0=\left\{\begin{array}{cc}0,& \mathrm{prio}\left(p\right)=2\\ \frac{2\&times;c_{\min }\&times;{\hat{E}}_L}{\mathrm{\&tau;}},& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L<\frac{\mathrm{\&tau;}}{2}\\ c_{\min },& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L\&GreaterEqual;\frac{\mathrm{\&tau;}}{2}\end{array}\right.$

And,

Wherein,

Prio (p) representes priority; τ is the delay requirement of setting; F is a frame per second;

It is the number that an average frame is divided into video packets; N is the number of all frame of video among the GOP; N _pIt is the number of P frame among the GOP;

Expression rounds up.

According to priority and/or transmission delay count value is set in the present embodiment, and, can guarantees the prioritised transmission of the high perhaps video packets that transmission delay is big of priority, thereby improve video transmission quality according to count value transmission of video bag.

One of ordinary skill in the art will appreciate that: all or part of step that realizes above-mentioned each method embodiment can be accomplished through the relevant hardware of program command.Aforesaid program can be stored in the computer read/write memory medium.This program the step that comprises above-mentioned each method embodiment when carrying out; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CD.

What should explain at last is: above each embodiment is only in order to explaining technical scheme of the present invention, but not to its restriction; Although the present invention has been carried out detailed explanation with reference to aforementioned each embodiment; Those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, perhaps to wherein part or all technical characteristic are equal to replacement; And these are revised or replacement, do not make the scope of the essence disengaging various embodiments of the present invention technical scheme of relevant art scheme.

Claims (12)

1. the transmission method of a video packets is characterized in that, comprising:

Confirm the priority of video packets, and the transmission delay of estimation video packets;

For video packets is distributed counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets;

According to the count value transmission of video bag of said counter, and adjust the corresponding count value of not transmitting of video packets.

2. method according to claim 1 is characterized in that, also comprises:

Different video packets is assigned in the different access style AC formations;

The transmission delay of said estimation video packets comprises: to the estimation of the video packets in the AC formation of setting transmission delay.

3. method according to claim 2 is characterized in that,

Said different video packets is assigned in the different AC formations, comprising: the video packets that will have first priority is assigned in the AC_VI formation, and the video packets that will have second priority is assigned in the AC_BE formation, and wherein first priority is higher than second priority;

Said to the estimation of the video packets in the AC formation of setting transmission delay, comprising: to the estimation of the video packets in AC_VI formation transmission delay.

4. according to each described method of claim 1-3, it is characterized in that the transmission delay of said estimation video packets comprises:

Set the transmission situation of the video packets of number, the transmission delay of estimation video packets according to the front of the character of physical layer transmission media and the current video packets that will estimate.

5. according to each described method of claim 1-3, it is characterized in that, said count value transmission of video bag according to said counter, and adjust the corresponding count value of not transmitting of video packets, comprising:

If the priority of the initial value of said counter and said video packets and/or the transmission delay of the said video packets relation of being inversely proportional to, the corresponding count value of the then little video packets of prioritised transmission count value, and the video packets that will not transmit subtracts 1; Perhaps,

If the priority of the initial value of said counter and said video packets and/or the transmission delay of said video packets are proportional, the corresponding count value of the then big video packets of prioritised transmission count value, and the video packets that will not transmit adds 1.

6. method according to claim 4 is characterized in that, the computing formula of the transmission delay of said estimation video packets is:

${\hat{E}}_L=\frac{E_{L,\min }+E_{L,\max }}{2},$

Wherein,

$E_{L,\min }=(1+\stackrel{\&OverBar;}{R})(\mathrm{\&alpha;}+{\mathrm{\&beta;}}_{\min }+{\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}\&times;L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\&delta;}),$

$E_{L,\max }=(1+\stackrel{\&OverBar;}{R})(\mathrm{\&alpha;}+{\mathrm{\&beta;}}_{\max }+{\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}\&times;L)-(T_{\mathrm{ACK}}+\mathrm{SIFS}+\mathrm{\&delta;}),$

$\mathrm{\&alpha;}=\underset{j=1}{\overset{L}{\mathrm{\&Sigma;}}}{T}_{j,\mathrm{trans}},$

$T_{j,\mathrm{trans}}=\mathrm{AIFS}[\mathrm{AC}\_\mathrm{VI}]+\frac{S_{j,\mathrm{data}}+S_{\mathrm{header}}}{\mathrm{\&upsi;}}+\mathrm{\&delta;}+\mathrm{SIFS}+\mathrm{\&delta;},$

${\mathrm{\&beta;}}_{\min }=\frac{\mathrm{aSlotTime}\&times;W_{\min }[\mathrm{AC}\_\mathrm{VI}]\&times;L}{2},$

${\mathrm{\&beta;}}_{\max }=\frac{\mathrm{aSlotTime}\&times;W_{\max }[\mathrm{AC}\_\mathrm{VI}]\&times;L}{2},$

${\stackrel{\&OverBar;}{T}}_{\mathrm{pause}}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}{t}_{-k,\mathrm{pause}},$

$\stackrel{\&OverBar;}{R}=\frac{1}{M}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}{r}_{-k},$

$T_{\mathrm{ACK}}=\frac{S_{\mathrm{ACK}}}{\mathrm{\&upsi;}},$

Wherein,

Transmission delay for estimation; S _{J, data}It is the size of j bag in the AC_VI formation; S _HeaderIt is the size of MAC layer header; S _ACKIt is the size of ACK bag; t _{-k, pause}K the guarantee for returns in front that is the video packets of current estimation kept away the break period in the process, and just backoff counter keeps the constant time of count value when listening to channel busy; r _-kIt is front k the bag number of retransmissions of the video packets of current estimation; υ is the transmission rate of physical layer; δ is the propagation delay of physical layer; M is the number of previous packet of the video packets of the current estimation of choosing set; AIFS [AC_VI]=2, aSlotTime are the DCF system time constants.

7. method according to claim 3 is characterized in that, said video packets with first priority comprises that priority is that 1 video packets and priority are 2 video packets, and the computing formula of the initial value of said counter is:

$c_0=\left\{\begin{array}{cc}0,& \mathrm{prio}\left(p\right)=2\\ \frac{2\&times;c_{\min }\&times;{\hat{E}}_L}{\mathrm{\&tau;}},& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L<\frac{\mathrm{\&tau;}}{2}\\ c_{\min },& \mathrm{prio}\left(p\right)=\mathrm{land}{\hat{E}}_L\&GreaterEqual;\frac{\mathrm{\&tau;}}{2}\end{array}\right.$

And,

Wherein,

Prio (p) representes priority;

τ is the delay requirement of setting;

F is a frame per second;

is the number that an average frame is divided into video packets;

N is the number of all frame of video among the GOP;

N _pIt is the number of P frame among the GOP;

expression rounds up.

8. the transmission equipment of a video packets is characterized in that, comprising:

Determination module is used for confirming the priority of video packets and the transmission delay of estimation video packets;

The counter distribution module is used to video packets and distributes counter, and the initial value of said counter is to confirm according to the priority of said video packets and/or the transmission delay of said video packets;

Processing module is used for the count value transmission of video bag according to said counter, and adjusts the corresponding count value of video packets of not transmission.

9. equipment according to claim 8 is characterized in that, also comprises:

The queue assignment module is used for the priority according to video packets, and the video packets of different priorities is assigned in the different access style AC formations.

10. equipment according to claim 9 is characterized in that,

Said queue assignment module specifically is used for the video packets with first priority is assigned to the AC_VI formation, and the video packets that will have second priority is assigned in the AC_BE formation, and wherein first priority is higher than second priority;

Said determination module specifically is used for the video packets estimation transmission delay to the AC_VI formation.

11. each described equipment according to Claim 8-10; It is characterized in that; Said determination module specifically is used for: set the transmission situation of the video packets of number, the transmission delay of estimation video packets according to the front of the character of physical layer transmission media and the current video packets that will estimate.

12. each described equipment is characterized in that according to Claim 8-10, said processing module specifically is used for:

If the priority of the initial value of said counter and said video packets and/or the transmission delay of the said video packets relation of being inversely proportional to, the corresponding count value of the then little video packets of prioritised transmission count value, and the video packets that will not transmit subtracts 1; Perhaps,

If the priority of the initial value of said counter and said video packets and/or the transmission delay of said video packets are proportional, the corresponding count value of the then big video packets of prioritised transmission count value, and the video packets that will not transmit adds 1.

Images