CN1751520A - Method and system for power efficient transmission of scalable video over wireless networks - Google Patents

Abstract

A method and system for reducing power consumption in a wireless network by adjusting the transmit energy for each bit at the physical layer and the retry limit at the MAC layer. The method includes creating a look-up table containing optimal pairs of N>lim<,E>t< for a plurality of different sets of transmission properties, wherein N>lim< is a retry limit and E>t<is a transmit energy per bit; determing a set of transmission properties for a sequence of scalable video to be transmitted over the wireless network; accessing the look-up table to obtain the optimal pair of N>lim<,E>t<, corresponding to the set of determined transmission properties; and transmitting the sequence of scalable video over the wireless network using the accessed optimal pair of N>lim<,E>t<.

Description

The method and system that is used for power efficient transmission of scalable video on wireless network

Technical field

The present invention relates generally to wireless network, and be particularly related to the method and system that is used at wireless network (for example comprising the wireless network of portable multimedia device) power efficient transmission of scalable video.

Background technology

Because the high-throughput that utilizes wireless lan (wlan) to provide, the real-time video communication on WLAN is just becoming feasible.Possible application comprises the video communication on mancarried device, the portable video server etc.The WLAN device of these types depends on battery usually and operates.Battery has the limited life-span and does not wish frequent recharging.Integrated along with the video transmission that needs high bandwidth and large transmission power, power (power supply) management becomes more important day by day.

Summary of the invention

The present invention considers to send the situation of scalable video data on WLAN, wherein adopt to retransmit as error-control schemes.An object of the present invention is on receiver, to keep constant video quality, make whole through-put power minimum simultaneously, perhaps opposite, in the situation of fixed transmission powers resource, the optimization video quality.

In the present invention, make the through-put power minimum in the constant video quality, transmission of power on the consideration physical layer and the retransmission scheme on medium access control (MAC) layer in order on receiver, to keep.Especially, the present invention is used for the emitted energy of each bit on the physical layer and the retry limit on the MAC layer reduces power consumption by adjusting.

Usually, the invention provides the method that a kind of power that is used for scalable video on the wireless network effectively transmits, comprising: create look-up table, this look-up table comprises the N that is used for a plurality of different transmission properties groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tIt is every bit emitted energy; The transmission characteristic group of definite scalable video sequence that will on wireless network, send; The visit look-up table is to obtain corresponding to the N that determines the transmission characteristic group _Lim, E _tBest right; With the N that uses visit _Lim, E _tBest right, on wireless network, send the scalable video sequence.

The present invention also provides a kind of effective system for transmitting of the power of scalable video on the wireless network that is used for, and comprising: look-up table, this look-up table comprises the N that is used for a plurality of different transmission properties groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tIt is every bit emitted energy; System is used for the transmission characteristic group of definite scalable video sequence that will send, and is used to visit look-up table on wireless network, to obtain corresponding to the N that determines the transmission characteristic group _Lim, E _tBest right; And system, be used to use the N that has visited _Lim, E _tBest on wireless network, sending the scalable video sequence.

The present invention also provides a kind of program product that is stored on the recordable media, is used to provide that the power of scalable video effectively transmits on the wireless network, comprising: the program code that is used for determining the transmission characteristic group of the scalable video sequence that will send on wireless network; With the program code that is used to visit look-up table, this look-up table comprises the N that is used for a plurality of different transmission characteristic groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tBe every bit emitted energy, to obtain corresponding to the N that determines the transmission characteristic group _Lim, E _tBest right, wherein use the N that visits _Lim, E _tBest right, on wireless network, send the sequence of scalable video.

Description of drawings

From below in conjunction with the detailed description of accompanying drawing to various aspects of the present invention, will understand these and other feature of the present invention more easily, wherein:

Fig. 1 shows maximum retry limit N _LimInfluence to whole through-put power;

Fig. 2 shows fine particle scalable (fine-granular-scalable) Video transmission system;

Fig. 3 shows the PSNR that is used for the sample video sequence;

Fig. 4 shows the transmission that is used for different retry limit;

Fig. 5 A-Fig. 5 C shows: for big P _L=1%, the transmission of power E that the needed every bit of given PSNR needs _tSuccessfully launch the average of the required transmission of dividing into groups; Successfully launch every bit transfer energy of (comprising re-transmission) bit;

Fig. 6 A-Fig. 6 C shows: for little p _L=0.01%, the transmission of power E that the needed every bit of given PSNR needs _tSuccessfully launch the average of the required transmission of dividing into groups; Successfully launch every bit transfer energy of (comprising re-transmission) bit;

Fig. 7 shows the comparison of power consumption and distance;

Fig. 8 shows flow chart according to an embodiment of the invention;

Fig. 9 shows transmission system according to an embodiment of the invention;

Figure 10 shows the computer system that is used to realize power manager of the present invention.

Should be noted that these accompanying drawings only schematically show, and do not plan to describe special parameter of the present invention.These accompanying drawings only are used to describe typical aspect of the present invention, and therefore should not be considered limiting scope of the present invention.

Embodiment

The invention describes and be used to reduce wireless network and (for example, WLAN) go up the method and system of the transmission power consumption of scalable video communications.This is by requiring to select maximum retransmission to realize according to quality and delay.Therefore, keep constant end-to-end video quality by adjusting transmitter SNR.For different retry limit, thereby for different transmitters SNR, we obtain different power consumptions.The present invention finds and uses transmission power level to minimize to be used for the whole energy that the effective scalable video of power transmits.Utilize the present invention, in the situation of giving the basic channel condition (SNR) that is subjected to the distance affects between noise, interference and transmitter and the receiver surely, by adjusting retransmission limit and transmission power level, realize that the power of scalable video on the WLAN effectively transmits.

Referring now to Fig. 1 (a)-Fig. 1 (d),, maximum retry limit N is shown _LimInfluence to whole through-put power.Go out as shown, along with retry limit increases, in order to keep identical end-to-end video quality, (1) video flowing can be tolerated higher packet loss rate (loss rate); (2) every bit emitted energy is lower; (3) number of retransmissions increases or remains unchanged; (4) whole through-put power changes.

In general, retry limit is big more on the MAC layer, and then the transmitter number of retransmissions that can have is just many more.Therefore, number of retransmissions (comprising transmission first and re-transmission subsequently) is the retry limit N shown in Fig. 1 (a) _LimContinuous increase function.On the other hand, along with the number of transmissions increases, the error control ability is enhanced, and therefore in order to keep the given quality on the receiver, the packet loss rate before any re-transmission all may be higher, and promptly data flow can be tolerated because more mistakes that transmission is introduced.Relation between packet loss rate and the retry limit is displayed among Fig. 1 (b).Obviously, each transmission packets energy is the reduction function of packet loss rate.Thereby it is the retry limit N shown in Fig. 1 (c) _LimThe reduction function.Integration map 1 (a) and Fig. 1 (c) have the optimum N that makes the power consumption minimum as the whole power of the function of transmission of power and the number of transmissions ^* _Lim(Fig. 1 (d)), thereby extending battery life.

As an illustrative example, the video flowing of fine particle scalable (FGS) coding will be launched.On the MAC layer, retry limit requires and the basic channel condition applicable to video quality.On physical layer, can adjust the energy of emission bit.In analysis subsequently, suppose that bit stream sends on additive white Gaussian noise (AWGN) channel, and analyze the theory influence of retransmission limit and transmission of power whole through-put power.Then, propose to be used to select optimal point of operation so that the numerical analysis of whole minimise power consumption.

Analytical model

The system 10 that figure 2 illustrates among the present invention to be considered.In system 10, video flowing is compressed by fine particle scalable (FGS) encoder 12, utilizes differential phase shift keying to modulate, and sends via basic additive white Gaussian noise (AWGN) channel 14.According to retry limit on video quality requirement and the basic channel condition adjustment MAC layer 16 and the emitted energy on the physical layer 18.Do not use channel encoder at the MAC layer.

The distortion that is caused by FGS encoder 12 at first is described.In part subsequently, pass parameter and power consumption that adjustment MAC layer 16 and physical layer 18 cause given distortion on the receiver through discussion.

The distortion model of FGS video encoder

The FGS coding provides level and smooth deterioration, to adapt to the network condition of continuous variation.FGS encoder 12 comprises basal layer (base layer) encoder 20 and enhancement layer encoder 22.Use the motion compresses coding method to compress basal layer by Base layer encoder 20; Enhancement layer encoder 22 is based on the fine particle coding method.In this is discussed, suppose that no any mistake ground receives all basal layer bits.Enhancement data is organized as grouping and sends via unreliable channel.

The PSNR ratio performance of FGS encoder

FGS encoder 12 provides the almost linear relation between enhancement layer bit rate and the peak signal-noise ratio (PSNR), as is used for the shown in Figure 3 of sample video sequence.This linear function can be write as follows:

PSNR＝k _FGSR _s+c _FGS (1)

Wherein, R _sBe the source bit rate of having encoded, and PSNR is corresponding video PSNR.In Fig. 3, by lowest mean square difference method derived parameter.For sample video sequence, listed parameter value at table 1 with the quantization step coding of the frame rate of 30fps and 10.From Fig. 3, as can be seen, between measurement data and linear model, there is good coupling.

Parameter type	Parameter value
		Big or small M (byte) divides into groups	1000
k FGS(dB/Mbps)	1.66
		c FGS(dB)	30.29
R(Mbps)	2.84
		R bl(Mbps)	0.67

The setting of table 1. simulation parameter

Mean P SNR when having packet loss on the receiver

In the former part, show: if zero defect occurs during the transmission, then the reconstructed video quality of measuring by PSNR is the linear function of coded bit stream.To be presented in the PSNR of decoded video sequence when introducing transmission error now, suppose the video sequence of fr fps frame rate, wherein each coded frame by the N of base layer data and enhancement data _ElGrouping constitutes.Suppose a grouping mistake when occurring, be dropped corresponding to all enhancement layer packet subsequently of same frame of video.When in the one i grouping of a correct reception image duration, receiver R _iOn corresponding data rate be:

R _i＝fr×i×M+R _bl (2)

Wherein M is the grouping size, and R _BlIt is the data rate of basal layer.The parameter value that is used for this open numerical analysis use is listed in the table 1.On receiver, video PSNR will be

PSNR _i＝k _FGSR _i+c _FGS (3)

Mean P SNR on the receiver is

$\mathrm{PSNR}=\underset{i=0}{\overset{N_{\mathrm{el}}}{\mathrm{\&Sigma;}}}{p}_i{\mathrm{PSNR}}_i$

$=\underset{i=0}{\overset{N_{\mathrm{el}}}{\mathrm{\&Sigma;}}}{p}_i(k_{\mathrm{FGS}}{R}_i+c_{\mathrm{FGS}})---\left(4\right)$

$=k_{\mathrm{FGS}}\underset{i=0}{\overset{N_{\mathrm{el}}}{\mathrm{\&Sigma;}}}{p}_i{R}_i+c_{\mathrm{FGS}}$

P wherein _iIt is the probability that successfully receives an i grouping.

Definition those data that receiver kept are valid data, and the valid data amount that is defined in the second is effective data rate R _El, this can followingly calculate:

$R_{\mathrm{el}}=\underset{i=0}{\overset{N_{\mathrm{el}}}{\mathrm{\&Sigma;}}}{p}_i{R}_i---\left(5\right)$

We obtain

PSNR＝k _FGSR _el+c _FGS (6)

Therefore, as long as we can access R _ElData rate, just expect that receiver can reach corresponding mean P SNR.

If the packets remaining proportion of goods damageds after retransmitting are P _L,

$p_i=\left\{\begin{array}{cc}{(1-p_L)}^i{p}_L,\mathrm{for}& i=\mathrm{0,1},...,N_{\mathrm{el}}-1\\ {(1-p_L)}^{N_{\mathrm{el}}},\mathrm{for}& i=N_{\mathrm{el}}\end{array}\right.---\left(7\right)$

Merge formula (2), (5) and (7), R _ElCan be written as follows,

$\begin{array}{c}{R}_{\mathrm{el}}=\underset{i=0}{\overset{N_{\mathrm{el}}-1}{\mathrm{\&Sigma;}}}[{(1-p_L)}^i{p}_{L}i+{(1-p_L)}^{N_{\mathrm{el}}}{N}_{\mathrm{el}}]\mathrm{Mfr}+R_{\mathrm{bl}}\\ =[\frac{1-p_L}{p_L}-\frac{{(1-p_L)}^{N^{\mathrm{el}}+1}}{p_L}]\mathrm{Mfr}+R_{\mathrm{bl}}\end{array}---\left(8\right)$

For N wherein _ElWith the special algorithm that M is fixed, R _ElBy p _LDetermine.Thereby, utilize packets remaining error rate p _LJudge the mean P SNR on the receiver side.In part subsequently, will show P _LHow relevant with retry limit, emission SNR and power consumption on the physical layer on the MAC layer.

Mode

To show the retry limit N on the physical layer below _LimHow SNR controls P with emission _L, i.e. PSNR on the receiver.Message bit stream is grouped into grouping, and each grouping comprises M information bit.Detect the packetized memory that received at receiver when mistake, (even a single bit error can cause the grouping mistake) appears in the grouping mistake.Grouping is wrong probability P _P0Depend on the signal to noise ratio that every bit receives.At first physical layer will be discussed, wherein bit error rate (BER) is by channel characteristics that is applied to each bit and emitted energy E _tDetermine.Then, will reduce on the receiver side mistake with discuss retransmitting and by use a plurality of transmission how to introduce the mode of additional energy consumption for a video packets.

Packet error rate P _P0

For for simplicity, suppose that channel is an awgn channel, DPSK is used for modulation and E _tIt is every bit emitted energy.The energy per bit E that has received on the receiver _bAnd the path gain h between two mobile radio stations is proportional, i.e. E _b=hE _t, wherein path gain depends on two distances between the mobile radio station, wherein h is given by following formula:

h＝cd ^-α (9)

Wherein c is a constant, and d is two distances between the station.In this example, α=3.6.Select the value of c, make that the every bit SNR that has received is 2dB to 16dB when two terminals apart during 100m.Bit error rate (BER) (BER) is

$p_b\left(E_b\right)=\frac{1}{2}{e}^{\frac{E_b}{N_0}}---\left(10\right)$

Wherein, N ₀It is noise power spectral density.

When existence even a single bit error, the grouping mistake takes place.For the grouping of M bit, packet error rate is

${\mathrm{<figure-callout\; id="0"\; label="p\; p"\; filenames="A20048000457700181.png,A20048000457700182.png"\; state="\{\{state\}\}">p</figure-callout>}}_p=1-(1-p_b\left(E_b\right))M=1-(1-\frac{1}{2}{e}^{\frac{E_b}{N_0}})---\left(11\right)$

Packets remaining proportion of goods damageds p _L

In WLAN, re-transmission is used as error-control schemes.Only at all N _LimWhen+1 transmission all is wrong, grouping just can not successfully be passed through channel.Therefore, the packets remaining error rate is to be grouped in N _LimAfter+1 transmission is wrong probability, and this packets remaining error rate is

$p_L={p_{p0}}^{N_{\lim }+1}---\left(12\right)$

As shown in Figure 4, if retry limit is higher, then can correctly send more grouping.

The average transmission times N _Tr

As shown in Figure 4, send each video packets, successfully sent or reach retry limit until it.The probability that successfully sends video packets when attempting for the n time is And the transmission of video packets reaches retry limit and the probability that successfully do not sent is Generally speaking, the average time of video packets transmission is

$N_{\mathrm{tr}}(N_{\lim }=\underset{n=1}{\overset{N_{\lim }+1}{\mathrm{\&Sigma;}}}{{\mathrm{np}}_{p0}}^{n-1}(1-p_{p0})+(N_{\lim }+1){p_{p0}}^{N_{\lim }+1}---\left(12\right)$

Total transmission of power

From formula (12), can see that for a video packets, because the restriction of MAC layer retry and successfully sent or be abandoned, employed average energy is

E _p(E _t，N _lim)＝E _t×N _tr(N _lim)×M (13)

For the video sequence of fr fps frame rate and for comprising N in the enhancement layer _ElEach frame of grouping, the power consumption of enhancement data is

P _all(E _t，N _lim)＝E _t×N _tr(N _lim)×M×N _el×fr (14)

Therefore optimization problem of the present invention can be expressed as

Mli P _AllStand to postpone and bandwidth constraint.

In this example, suppose to have sufficiently high bandwidth.If the upper limit of retry limit is set to satisfy deferred constraint, then optimization problem can be confirmed as

Min P _all(E _t，N _lim)＝E _t×N _tr(N _lim)×M×N _el×fr

Obey N _Lim＜N _Upper

Numerical result

In this part, check the performance of the inventive method.At first, consider: distance is fixedly the time between transmitter and receiver, the performance under the different quality requirement.Then, consider following situation: quality requirement is identical, but receiver moves everywhere.Summarized the parameter value that in emulation, uses in the table 1.Here, the sample video sequence is encoded with the 30fps frame rate, and transmit data rate is 2.84Mbps, corresponding to the PSNR of the 35dB when not going wrong.Base layer data speed is 0.67Mbps, and is 30.29dB from the PSNR of basal layer reconstruct.Enhancement data is divided into 9 groupings, and each grouping comprises 1000 bytes.On physical layer, when two mobile radio stations when the 10m, the signal to noise ratio of selective reception from 2dB to 16dB.Maximum retry limit is set at N _Upper=20, to guarantee in deferred constraint, a receiving grouping.

Accompanying drawing (that is, Fig. 5 A-C, Fig. 6 A-C) for the demonstration performance utilizes scaling factor to come the normalization power consumption

$c_{\mathrm{sf}}=\frac{1}{\mathrm{<figure-callout\; id="0"\; label="c\; d"\; filenames="A20048000457700181.png,A20048000457700182.png"\; state="\{\{state\}\}">c</figure-callout>}}{d}_{}^{}{}_0^{\mathrm{\&alpha;}}{N}_{0}M{N}_{\mathrm{el}}\mathrm{fr}---\left(18\right)$

That is, the value shown in the figure is

$P_{\mathrm{sf}}=\frac{E_b}{N_0}{\left(\frac{d}{d_0}\right)}^{\mathrm{\&alpha;}}{N}_{\mathrm{tr}}---\left(19\right)$

For different the minimizing of requiring of PSNR

In this part, analyze when distance is fixed on d=10m the mode that optimum changes with the PSNR requirement.With the different PSNR requirements of considering on the receiver side.Two different p _LBe used for the different quality requirement of emulation.The result is illustrated among Fig. 5 A-C and Fig. 6 A-C.

In Fig. 5 A-C, illustrate respectively: for every bit transfer ENERGY E of given PSNR _t, succeed in sending up a required average transmission number of times of grouping, and the every bit transfer energy that succeeds in sending up (comprising re-transmission) bit, as for corresponding to P _LThe formula of=1% given video quality (14) is shown in (15) and (17).Shown in Fig. 5 A, when retry limit increases, can utilize lower energy per bit E _tObtain identical video quality.In addition, shown in Fig. 5 B, when retry limit increases, when having serious channel impairment, can there be more re-transmission to dispose.Combined diagram 5A and Fig. 5 B then show power consumption in Fig. 5 C.Power consumption such as formula utilize c in (18) _SfCalibrate.Optimum OP appears at N at this _Lim=1 place promptly, increases every bit transfer ENERGY E _tAlways be compared to high P _LMore times transmission is more effective.With power consumption on the optimum and N _LimPower consumption on=10 compares, and can obtain about 50% power-saving.

In Fig. 6 A-C, show p _L=0.01% situation, expression is for the higher receiver, video quality of same channel conditions among Fig. 5 A-C.Fig. 6 A-C and Fig. 5 A-C are compared, can see,, need bigger retry limit obtain high error correcting capability for high-quality more.Especially, shown in Fig. 6 C, for p _L=0.01%, optimum is along with retransmission limit N ^* _Lim=3 together occur.

Power consumption on the minimized distance scope

In this part, the situation (for example, emulation home environment, the distance from 10m to 20m) when the analysis receiving terminal is mobile everywhere.For each distance, calculate (N _Lim, E _t) best right.In Fig. 7, summarize the result.Note that E _tWith respect to By normalization, d wherein ₀=10m.Have found that, when distance becomes big, preferred high retry limit.N _Lim=10 power consumption also is displayed among Fig. 7.Compare these two curves, algorithm of the present invention surpasses wherein N _LimBe set to the scheme of big value.If N _LimBe set to little value, for example N _Lim=1, then it repeats best curve for the short distance up to d=16 in this emulation, but it can not be applicable to big distance, and promptly quality can not remain on the expection level.For N _Lim=10 schemes have fluctuation and have some incompatibility for best curve.This is due to the fact that for N _LimAnd E _tDiscrete setting, in fact resulting PSNR is not constant, and always is higher than desired value.

Implement

802.11 the MAC/PHY standard allows device present (on the fly) to change transmission energy level and retry limit.Increase the retry limit N on the MAC layer _LimAnd the transmission energy level E on the physical layer (PHY) _tProvide higher mistake proofing for the data that sent.Yet in order to reach same video quality on receiver, they differently work on the power consumption meaning.The present invention determines to make (the N of minimise power consumption _Lim, E _t) best right.

In Fig. 8 and Fig. 9, provide respectively and show enforcement flow process Figure 100 of the present invention and the Figure 200 of system.This enforcement provides " power manager 102 ", can be in the operation of this power manager that distributes between base station B and one or more portable terminal TER on the wireless network.

At step S1, calculated in advance for adaptation rule, channel 114 conditions and the video sequence characteristic of the discrete setting of quality requirement (for example), and be stored among the B of base station as look-up table 104 for the PSNR of FGS encoder 112 and the relation between the speed.For every group of data, in look-up table 104, provide (N _Lim, E _t) optimum operation right.

At step S2,, detect qos requirement, channel condition and video sequence characteristic and report to power manager 102 in the communication period of scalable video sequence.According to this criterion, power manager 102 is determined (N by visiting precalculated look-up table 104 _Lim, E _t) optimum operation is right.From the right N of optimum operation _LimBe provided for MAC layer 116, and from the right E of optimum operation _tBe provided for PHY layer 118.At step S3, these operating points of frequent updating (for example, after time T) are so that follow the specific feature of application of time dependent wireless channel 114.

Should be appreciated that the present invention can realize with the combination of hardware, software or hardware and software.The computer/server system of any kind-or be suitable for carrying out the miscellaneous equipment of method described here-be suitable for implementation of the present invention.The typical combination of hardware and software can be the general-purpose computing system with computer program, when this computer program is loaded and carries out, finishes correlation method described here.As selection, can utilize special-purpose computer, this computer comprises the specialized hardware that is used to carry out one or more functional tasks of the present invention.The present invention can also be embedded in the computer program, and it comprises all individual features that can implement method described here, and in being loaded into computer system the time, can carry out these methods.Computer program, software program, program, software are represented any expression formula with the instruction set of any language, code or notation in the present context, described instruction is used to make the system with information processing capability or directly carries out specific function, perhaps following each or carry out specific function after two: (a) be transformed into another language, code or notation; And/or (b) with the reproduction of different materials form.

An example of computer system 300 is presented among Figure 10.Computer system 300 generally includes: CPU (CPU) 302; Memory 304; I/O (I/O) interface 306; Bus 308; External device (ED) 310; With database 312.User 314 can with computer system 300 reciprocations (for example, to generate look-up table 104 (Fig. 9)).

Computer 300 can comprise any universal or special system that utilizes standard operation system software, its be designed to drive specific hardware operation and can be compatible mutually with other system parts and I/O controller.CPU302 can comprise that single processing unit, a plurality of processing units or can be distributed on that can parallel work-flow are positioned on the one or more processing units that (for example, are distributed on the client-server) on one or more positions.Memory 304 can comprise the data storage and/or the transmission medium of any known type, comprises magnetic media, optical medium, random-access memory (ram) etc.In addition, be similar to CPU 302, memory 304 can reside on the single physical position, comprises the memory of one or more types, perhaps is distributed on a plurality of physical systems with various forms.

I/O interface 306 can comprise any known system that is used for one or more external device (ED) 310 exchange messages.External device (ED) 310 can comprise the input/output device of any known type that can communicate by letter with I/O interface 306, no matter whether it has attachment device.Bus 308 provides communication link between each parts of computer 300, and can comprise the transmission link of any known type equally, comprises electricity, light, Radio Link etc.Other well-known components also can be incorporated in the computer 300.

Database 312 can provide the storage of carrying out information required for the present invention.For example, look-up table 104 (Fig. 9) can be stored in the database 312.Database 312 can comprise one or more storage devices, such as disc driver or CD drive.In addition, database 312 can comprise and being distributed in such as LAN, WAN or the data on the internet.

Power manager 320 according to the present invention is expressed as computer program code and is stored in the memory 304.Power manager 320 comprises: information system 322 is used to determine/receive " transmission characteristic ", such as qos requirement, channel condition, video sequence characteristic etc.; With optimization system 324, be used for precalculated look-up table by accessing database 312 storages, be identified for (the N of each time T _Lim, E _t) optimum operation right.N _LimAnd E _tOffer MAC and PYS layer 116,118 (Fig. 9) via I/O interface 306 subsequently.

The above explanation of various aspects of the present invention provides in order to describe with illustration purpose, do not plan exhaustive or limit the invention to disclosed precise forms, and obviously many modifications and variations all is possible.Can be that predetermined being included in of conspicuous such modifications and variations utilized within the defined scope of the present invention of appended claim to those skilled in the art.

Claims (18)

1, a kind of method that is used for power efficient transmission of scalable video on wireless network comprises:

Create look-up table, this look-up table comprises the N that is used for a plurality of different transmission characteristic groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tIt is every bit emitted energy;

The transmission characteristic group of definite scalable video sequence that will on wireless network, send;

Visit this look-up table, to obtain N corresponding to fixed transmission characteristic group _Lim, E _tBest right; With

Use accessed N _Lim, E _tBest right, the sequence of transmission scalable video on wireless network.

2, method according to claim 1, wherein every group of transmission characteristic comprises at least one among quality of service requirement, channel condition and the video sequence characteristic.

3, method according to claim 1 also comprises:

Use fine particle ges forschung device to the scalable video sequential coding.

4, method according to claim 1 wherein uses Base layer encoder and enhancement layer encoder to the scalable video sequential coding.

5, method according to claim 1 also comprises:

N _LimOffer medium access control (MAC) layer of wireless network; With E _tOffer the physical layer of wireless network.

6, method according to claim 1 also comprises:

Repeat to determine, visit and forwarding step, to follow the temporal change characteristic of wireless network.

7, a kind of system that is used for power efficient transmission of scalable video on wireless network comprises:

Look-up table, this look-up table comprise the N that is used for a plurality of different transmission characteristic groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tIt is every bit emitted energy;

System is used for the transmission characteristic group of definite scalable video sequence that will send, and is used to visit look-up table on wireless network, to obtain corresponding to the N that determines the transmission characteristic group _Lim, E _tBest right; With

Be used to use accessed N _Lim, E _tBest on wireless network, sending the system of scalable video sequence.

8, system according to claim 7, wherein every group of transmission characteristic comprises at least one among quality of service requirement, channel condition and the video sequence characteristic.

9, system according to claim 7 also comprises:

Be used for fine particle ges forschung device to the scalable video sequential coding.

10, system according to claim 7 also comprises:

Be used for Base layer encoder and enhancement layer encoder to the scalable video sequential coding.

11, system according to claim 7, wherein wireless network comprises medium access control (MAC) layer and physical layer, and N wherein _LimBe provided for the MAC layer of wireless network, and E _tBe provided for the physical layer of wireless network.

12, system according to claim 7 determines that wherein system upgrades the transmission characteristic group after predetermined space, and the visit look-up table, to obtain the N that has upgraded corresponding to definite transmission characteristic group of having upgraded _Lim, E _tBest right, and the N that upgraded of transmitting system utilization wherein _Lim, E _tBest to sending the scalable video sequence via wireless network.

13, a kind of program product that is stored on the recordable media is used to provide that the power of scalable video effectively transmits on the wireless network, comprising:

The program code that is used for the transmission characteristic group of definite scalable video sequence that will on wireless network, send; With

Be used to visit the program code of look-up table, this look-up table comprises the N that is used for a plurality of different transmission characteristic groups _Lim, E _tThe best is right, wherein N _LimBe retry limit, and E _tBe every bit emitted energy, to obtain corresponding to the N that determines the transmission characteristic group _Lim, E _tBest right, wherein use accessed N _Lim, E _tBest on wireless network, sending the scalable video sequence.

14, program product according to claim 13, wherein every group of transmission characteristic comprises at least one among quality of service requirement, channel condition and the video sequence characteristic.

15, program product according to claim 13 wherein uses fine particle ges forschung device to the scalable video sequential coding.

16, program product according to claim 13 wherein uses Base layer encoder and enhancement layer encoder to the scalable video sequential coding.

17, program product according to claim 13 also comprises:

Be used for N _LimOffer the program code of medium access control (MAC) layer of wireless network; With

Be used for E _tOffer the program code of the physical layer of wireless network.

18, program product according to claim 13 also comprises:

Program code is used for upgrading the transmission characteristic group after predetermined space, and is used to visit look-up table, to obtain the N of renewal corresponding to the transmission characteristic group of having upgraded of determining _Lim, E _tBest right, and wherein utilize the N that has upgraded _Lim, E _tBest on wireless network, sending the scalable video sequence.

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