CN102833840B - Convex optimization power configuration method based on network coding cooperation system - Google Patents

Abstract

The invention discloses a convex optimization power configuration method based on a network coding cooperation system, which is characterized by comprising the following steps of: 1) a relay node calculates the first transmitted power WS of a first source node, the relay transmission power WR of the relay node and the second transmission power WT of a second source node; 2) the relay node sends a WS data value to the first source node and sends the WT data value of the second transmission power to the second source node; 3) the first source node sends information to the relay node according to WS; the second source node sends information to the relay node according to WT; and the relay node sends information according to WR. The convex optimization power configuration method based on the network coding cooperation system, which is disclosed by the invention, has the beneficial effects that the convex optimization power configuration technology can be used for updating the transmission power of each node in real time according to the working environment of the network coding cooperation system no matter in a single-relay network coding cooperation system or a multiple-relay network coding cooperation system, the outage capacity of the system is improved under the condition that no system energy consumption is increased.

Description

A kind of convex optimizing power collocation method of coding cooperative system Network Based

Technical field

The present invention relates to a kind of wireless relay system power distributing technique, particularly relate to a kind of convex optimizing power collocation method of coding cooperative system Network Based.

Background technology

Network code is applied in the middle of cable network at first, brings the raising of resource utilization ratio and network throughput ^[1], and there is more wide application prospect in wireless communications, but the multipath faidng that the broadcast characteristic of wireless channel is brought, noise makes transmission of wireless signals penalty.Space diversity reception to communicate has very large advantage in anti-fading, but it is to the volume of node, hardware, and price has higher requirement, all unrealistic in a lot of application scenario, so promoted generation and the research of cooperative diversity technique ^[2-4].In wireless environments frequent by both combine to obtain preferably systematic function ^[5-6].

The defect of prior art is: document [5] network code and cooperation technology reduce the outage probability of system, but document [5] supposes that the error probability of all nodes is consistent, does not have to consider that the channel condition information based on node carries out power division.Document [6] have studied the network coding cooperation in finite field, introduces error control code, improves the diversity gain of system, but does not consider the power division of cooperative node.Document [7] coding cooperative communication system Network Based, analyzes system from the angle of opportunistic cooperation, improves capacity usage ratio, but does not also consider the power division of node.In the cooperative system of majority, the energy of each node is all limited, in order to obtain optimal system performance under finite energy, although the power distribution problems between source node and partner node is subject to extensive concern ^[8-10].But an effective preferred plan is not all proposed.Cannot ensure, under the condition that system total transmitting power W is consistent, to be difficult to the outage capacity of guarantee system.

Background technology list of references

[1]Ahlswede R,Cai Ning,Li S Y R,and Yeung RW.Network informationflow[J].IEEE Transactions on Information Theory,2000,46(4):1204–1216.

[2]Laneman J N,Wornell G W.Distributed space-time-coded protocols forexploiting cooperative diversity in wireless networks[J].IEEE Transactions onInformation Theory,2003,49(10):2415-2425.

[3]Hunter T,Sanayei S,Nosritania A.Outage analysis of coded cooperation[J].IEEE Transaction on information Theory,2006,52(2):375-391.

[4]Laneman J N,Tse D N C,Womell G W.Cooperative diversity in wirelessnetworks:Efficient protocols and outage behavior[J].IEEE Transaction oninformation Theory,2004,50(12):3062-3080.

[5]Chen Yingda,Kishore S,Li Jing.Wireless Diversity through NetworkCoding[C]//IEEE Wireless Communications and Networking Conference,2006.

[6]Lei Xiao,Fuja T,Kliewer J.A network coding approach to cooperativediversity[J].IEEE Transaction on information Theory,2007,53(10):3714-3722.

[7]PENG C,ZHANG Q,ZHAO M,et al.Opportunistic network-codedcooperation in wireless networks[C]//Wireless Communications andNetworking Conference(WCNC2007).Hong Kong:IEEE Press,2007:3358-3363.

[8]Zhang Jingmei,Zhang Qi,Shao Chunju.Adaptive optimal transmit powerallocation for two-hop non-regenerative wireless relaying system[C].IEEEVehicular Technology Conference,2005.

[9]Sohaib S,So D K C.Power Allocation for Multi-Relay Amplify-And-ForwardCooperative Networks[C].IEEE International Conference onCommunications,2011.

[10]Mallick S,Kandhway K.Power Allocation for Decode-and-Forward CellularRelay Network with Channel Uncertainty[C].IEEE International Conferenceon Communications,2011.

[11] Tang Lun, Liu Tong, Chen Qianbin. relay system cooperative node is selected and power distribution strategies [J]. electronics and information journal, 32 (9): 2077-2082.

[12]Xiao Ming,Skoglund M.Multiple-User Cooperative Communications Basedon Linear Network Coding.[J].IEEE Transactions onCommunications,2010,58(12):3345-3351.

[13] Lv Ling, Yu Hongyi. the opportunistic relay [J] of physical-layer network coding grouping. electronics and information journal, 2009,31 (7): 1767-1770.

[14]Rossetto F,Zorzi M.Mixing network coding and cooperation for reliablewireless communications[J].IEEE Transactions on WirelessCommunications,2011,18(1):15-21.

[15]Peng Gong,Peng Xue,Daeyoung Park.Optimum Power Allocation in aNon-orthogonal Amplify-and-Forward Relay-Assisted Network[J].IEEEtransactions on Vehicular Technology,2011,60(3):890-900.

Summary of the invention

The object of the present invention is to provide a kind of convex optimizing power collocation method of coding cooperative system Network Based, under the condition that the total transmitting power W of the system of guarantee is consistent, improve the outage capacity of system.

Technical scheme of the present invention is as follows: a kind of convex optimizing power collocation method of coding cooperative system Network Based, and its key is to carry out as follows:

Step one: form single relayed communications network by the first source node, via node and the second source node;

First source node and the second source node send information respectively to via node;

Via node extracts the first channel gain α of the first source node and via node _sR;

Via node extracts the second channel gain alpha of the second source node and via node _tR;

Via node extracts the gross power W of described single relayed communications network;

Via node utilizes described first channel gain α _sR, second channel gain alpha _tRthe first transmitting power W of described first source node is calculated with gross power W _s, the repeat transmitted power W of via node _r, the second transmitting power W of the second source node _t;

$W_S=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

$W_R=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

$W_T=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

Wherein χ _sR=α ² _sR, χ _tR=α ² _tR, and definition calculates W _s, W _rwith W _tformula be convex optimizing power distribution formula;

Step 2: via node is according to repeat transmitted power W _rsend information to the first source node and the second source node, via node is by transmitting power W simultaneously _sdata value sends described first source node to, tells that the first source node adopts W _sperformance number carry out message transmission, via node is by transmitting power W _tdata value sends described second source node to, tells that the second source node adopts W _tperformance number carry out message transmission;

Step 3: in the communication process of described single relayed communications network inside:

Described first source node is always according to the first transmitting power W _stransmission information is to via node, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described second source node is always according to the second transmitting power W _ttransmission information is to via node, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described via node is always according to repeat transmitted power W _rsend information to the first source node and the second source node, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then returns execution step 2.

The power distributing technique of convex optimization is applied in network coding cooperation system by the present invention, takes into full account channel condition information, the outage capacity of system is stated as a convex problem, by obtaining convex excellent solution, obtains the power distribution result of convex optimization.Ensureing that, under the condition that system total transmitting power is consistent, the optimization realizing transmitting power distributes, outage probability is being dropped to minimum, improve the outage capacity of system.

Remarkable result of the present invention: the convex optimizing power collocation method providing a kind of coding cooperative system Network Based, in single relay system, channel condition information is substituted into convex optimizing power distribution formula, under the condition that the total transmitting power of the system of guarantee is consistent, draw the best transmit power of each node.For multi-relay cooperation system, after best relay is selected, all the other operations are consistent with single relay system.The power distributing technique of this convex optimization can upgrade the power of the transmission of each node in real time according to network coding cooperation system context, improve the outage capacity of system when not increasing system energy consumption.

Accompanying drawing explanation

Fig. 1 is single relayed communications network annexation figure;

Fig. 2 is workflow diagram of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described:

As shown in Figure 2: the convex optimizing power collocation method of a kind of wireless network, its key is to carry out as follows:

Step one: form single relayed communications network by the first source node S, via node R and the second source node T;

First source node S and the second source node T send information respectively to via node R;

Via node R extracts the first channel gain α of the first source node S and via node R _sR;

Via node R extracts the second channel gain alpha of the second source node T and via node R _tR;

Via node R extracts the gross power W of described single relayed communications network;

Via node R utilizes described first channel gain α _sR, second channel gain alpha _tRthe first transmitting power W of described first source node S is calculated with gross power W _s, the repeat transmitted power W of via node R _r, the second transmitting power W of the second source node T _t;

$W_S=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

$W_R=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

$W_T=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

Wherein χ _sR=α ² _sR, χ _tR=α ² _tR, and definition calculates W _s, W _rwith W _tformula be convex optimizing power distribution formula;

Via node R is according to repeat transmitted power W _rsend information to the first source node S and the second source node T, via node R is by transmitting power W simultaneously _sdata value sends described first source node S to, tells that the first source node S adopts W _sperformance number carry out message transmission, via node R is by transmitting power W _tdata value sends described second source node T to, tells that the second source node T adopts W _tperformance number carry out message transmission;

Step 3: in the communication process of described single relayed communications network inside:

Described first source node S is always according to the first transmitting power W _stransmission information is to via node R, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described second source node T is always according to the second transmitting power W _ttransmission information is to via node R, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described via node R is always according to repeat transmitted power W _rsend information to the first source node S and the second source node T, until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then returns execution step 2.

Operation principle of the present invention is as follows:

As shown in Figure 1, the first source node S and the second source node T be not all in the reliable communication range of the other side, and complete communication must by the cooperation of via node R.

Use g now _jkrepresent the channel fading coefficient of j, k two between node, to obey average be 0 variance be 1 rayleigh distributed, suppose that decline declines for quasistatic, carries out g in two time slots transmitting in data _jkremain unchanged and bi-directional symmetrical, i.e. g _jk=g _kj.With the first channel gain α _sR, second channel gain alpha _tRrepresent the channel gain between the first source node S, the second source node T and via node R respectively.D _jkrepresent the distance between source node j and via node R.

${\mathrm{\α}}_{\mathrm{jk}}=g_{\mathrm{jk}}/\sqrt{{d^v}_{\mathrm{jk}}}---\left(1\right)$

What v represented is path-loss factor, equals 3 or 4.

Contemplated by the invention two kinds of cooperative systems, a kind of is the network coding cooperation system of single relaying, and a kind of is the physical-layer network coding cooperative system of opportunistic relay.Physical-layer network coding completes the information exchange between two source nodes by two time slots, saves bandwidth resources.And by the selection of optimal relay node, obtain the diversity gain of system.

For best relay R _bestselection, adopt with the following method:

$R_{\mathrm{best}}=\underset{k}{\arg }\max \left\{\min \right\{{\left|{\mathrm{\α}}_{\mathrm{Sk}}\right|}^2,{\left|{\mathrm{\α}}_{\mathrm{kT}}\right|}^2\left\}\right\}---\left(2\right)$

Double bounce repeated link S-R-T quality is weighed by less one of channel gain in double bounce, then inside all via nodes maximum one of selective channel gain as best relay.After best relay is selected, best relay and two source nodes are carried out to the power division of convex optimization.

The signal to noise ratio of link is expressed as follows:

γ _jk＝χ _jkW _i(3)

χ _jk=α ² _jk, obedience average is 1/d _jk ^vexponential distribution, W _iwhat represent is the transmitting power of each node.Under wireless fading channel, link signal to noise ratio is caused to be less than signal-noise ratio threshold γ when Link Fade amplitude is excessive _thin time, will interrupt.Suppose that the outage probability of single relay system is P _out, can be expressed as:

P _out＝1-[Pr(γ _SR＞γ _th)][Pr(γ _TR＞γ _th)][Pr(γ _RS＞γ _th)][Pr(γ _RT＞γ _th)] (4)

Because γ _jkobey negative distribution, so P _outcan be expressed as:

$P_{\mathrm{out}}=1-e^{-{\mathrm{\γ}}_{\mathrm{th}}(\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{SR}}}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{TR}}}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{RS}}}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{RT}}})}---\left(5\right)$

In formula (5) that represent is link signal to noise ratio γ _jkaverage.Formula (3) is substituted in formula (5), can P be obtained _outexpression formula:

$P_{\mathrm{out}}=1-e^{-{\mathrm{\γ}}_{\mathrm{th}}(\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{SR}}{W}_S}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{TR}}{W}_T}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{RS}}{W}_R}+\frac{1}{{\stackrel{\‾}{\mathrm{\γ}}}_{\mathrm{RT}}{W}_R})}---\left(6\right)$

W in formula _s, W _t, W _rrepresent the transmitting power of the first source node S, the second source node T, via node R respectively.Optimized power distribution strategies is exactly the outage probability that acquisition system is minimum under system total power W measures certain limited case, namely maximum outage capacity.Optimization problem can be expressed as with mathematic(al) representation

$\begin{array}{cc}\min & P_{\mathrm{out}}=1-e^{-{\mathrm{\γ}}_{\mathrm{th}}(\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{SR}}{P}_S}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{TR}}{P}_T}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{RS}}{P}_R}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{RT}}{P}_R})}---\left(7\right)\end{array}$

subject to W _S+W _T+W _R＝W

Mathematic(al) representation can be reduced to

$\begin{array}{cc}\max & {-\mathrm{\γ}}_{\mathrm{th}}(\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{SR}}{W}_S}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{TR}}{W}_T}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{RS}}{W}_R}+\frac{1}{{\stackrel{\‾}{\mathrm{\χ}}}_{\mathrm{RT}}{W}_R})\end{array}---\left(8\right)$

subject to W _S+W _T+W _R＝W

Observation type (8), this is a convex problem, can be solved the transmitted power of each node by structure target function

$W_S=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

$W_R=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}---\left(9\right)$

$W_T=W\frac{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}}{\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\χ}}_{\mathrm{SR}}+{\mathrm{\χ}}_{\mathrm{TR}}}}$

Contrast with legacy network: the present invention is directed to legacy network and encode and the opportunistic relay scheme of physical-layer network coding, the system break capacity under the power division of convex optimization and the carrying out under average power allocation are contrasted.

Under the condition of single via node, suppose relay node R is positioned at the centre of the first source node S and the second source node T, and the first source node S and the second source node T carry out the exchange of information in the mode that legacy network is encoded.For the first source node S or the second source node T, receive the outage probability of information ^[12]:

$P_1=\mathrm{Pr}({\mathrm{\&chi;}}_{\mathrm{SR}}<{\mathrm{\&theta;}}_1\&cup;{\mathrm{\&chi;}}_{\mathrm{RT}}<{\mathrm{\&theta;}}_1)=1-\exp ({-\mathrm{\&theta;}}_1/{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}})---\left(10\right)$

In formula θ ₁=3 (2 ^{3 ρ}-1)/2SNR, has spectrum efficiency ρ=R/W (bit/s/Hz), SNR=W/N ₀.By P ₁the total outage probability of the system that draws is:

Now system is under constant power distributive condition, has and be updated in formula (6), system break probability is:

$P_{\mathrm{out}}=1-\exp ({-2\mathrm{\&theta;}}_1/{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}})---\left(12\right)$

Contrast (11) and (12), under constant power distribution condition, the system break probability that two kinds of methods draw is consistent, illustrates to carry out the outage probability of computing system by signal-noise ratio threshold and outage capacity is feasible, and this is to the outage capacity important in inhibiting of analytical system.

Under legacy network coding, system with outage capacity is ^[12]:

$C_{\mathrm{sum}}=\frac{2}{3}{\log }_2(1-\ln (1-P_1)\frac{2\mathrm{SNR}}{3}{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}})---\left(13\right)$

Use signal-noise ratio threshold γ _thcan be expressed as:

$C_{\mathrm{sum}}=\frac{2}{3}{\log }_2(1+2{\mathrm{\&gamma;}}_{\mathrm{th}})---\left(14\right)$

Power division is optimized to node each in system, draws the outage probability P' of system _outfor:

${P^{\&prime;}}_{\mathrm{out}}=1-\exp (-\frac{{\mathrm{\&gamma;}}_{\mathrm{th}}}{W}\frac{{(\sqrt{{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SR}}}+\sqrt{{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{TR}}}+\sqrt{{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SR}}+{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{TR}}})}^2}{{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SR}}{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{TR}}})---\left(15\right)$

Under the condition that outage probability is consistent, namely system break capacity is equal, can obtain the signal-noise ratio threshold under the distribution of convex optimizing power system break capacity under convex optimizing power distributes:

${C^{\&prime;}}_{\mathrm{sum}}=\frac{2}{3}{\log }_2(1-\frac{4}{3+2\sqrt{2}}\ln (1-P_1)\mathrm{SNR}{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}})---\left(16\right)$

The opportunistic relay of physically based deformation layer network coding:

There is multiple via node in opportunistic relay expression system, suppose relay node is positioned at the centre of the first source node S and the second source node T, and the first source node S and the second source node T adopt the mode of physical-layer network coding to carry out information exchange by via node.Suppose have all relayings for the first source node S or the second source node T, receive the outage probability of information:

$P_2=\underset{i=1}{\overset{N}{\mathrm{\&Pi;}}}(1-\exp (-{\mathrm{\&theta;}}_2/{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}}))--\left(17\right)$

Wherein θ ₂=3 (2 ^{2 ρ}-1)/2SNR.

System break capacity is ^[12]:

$C_{\mathrm{sum}}={\log }_2(1-\ln (1-{P_2}^{1/N})\frac{2\mathrm{SNR}}{3}{\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}})---\left(18\right)$

When ensureing that system break probability is consistent, namely system break capacity is equal, can draw the system break capacity under optimizing power distributes equally:

Above analysis is all the centre position being positioned at the first source node S and the second source node T based on via node.For the cooperative system of via node position changeable, the convex optimizing power allocation algorithm that the present invention proposes is applicable equally.Distance between first source node S and the second source node T is d _sT, suppose relay from the distance of the first source node S is distance from the second source node T is

${\stackrel{\&OverBar;}{\mathrm{\&chi;}}}_{\mathrm{SRT}}=\frac{1}{{(\&PartialD;d)}^v+{(1-\&PartialD;)}^v{d}^v}---\left(20\right)$

When ensureing that system break probability is consistent, namely system break capacity is equal, can calculate the signal-noise ratio threshold γ under the distribution of convex optimizing power _th=θ W Δ, and then the outage capacity of system can be obtained.Wherein

$\mathrm{\&Delta;}=[{\&PartialD;}^v+{(1-\&PartialD;)}^v]/[{\&PartialD;}^v+{(1-\&PartialD;)}^v+\sqrt{{\&PartialD;}^v{(1-\&PartialD;)}^v+{(1-\&PartialD;)}^{2v}}+\sqrt{{\&PartialD;}^v{(1-\&PartialD;)}^v+{\&PartialD;}^{2v}}],$ θ=θ under legacy network coding ₁, under physical-layer network coding opportunistic relay scheme, θ=θ ₂.

Under the condition that gross power is certain, the power division of convex optimization brings the lifting of system break capacity, and to physical-layer network coding opportunistic relay system, via node number is more, and the lifting of system break capacity is larger.

Claims (1)

1. a convex optimizing power collocation method for coding cooperative system Network Based, is characterized in that carrying out as follows:

Step one: form single relayed communications network by the first source node (S), via node (R) and the second source node (T);

First source node (S) and the second source node (T) send information respectively to via node (R);

Via node (R) extracts the first channel gain α of the first source node (S) and via node (R) _sR;

Via node (R) extracts the second channel gain alpha of the second source node (T) and via node (R) _tR;

Via node (R) extracts the gross power W of described single relayed communications network;

Via node (R) utilizes described first channel gain α _sR, second channel gain alpha _tRthe first transmitting power W of described first source node (S) is calculated with gross power W _s, the repeat transmitted power W of via node (R) _r, the second transmitting power W of the second source node (T) _t;

$W_S=W\frac{\sqrt{{\mathrm{\&chi;}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}+{\mathrm{\&chi;}}_{\mathrm{TR}}}}$

$W_R=W\frac{\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}+{\mathrm{\&chi;}}_{\mathrm{TR}}}}{\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}+{\mathrm{\&chi;}}_{\mathrm{TR}}}}$

$W_T=W\frac{\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}}}{\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{TR}}}+\sqrt{{\mathrm{\&chi;}}_{\mathrm{SR}}+{\mathrm{\&chi;}}_{\mathrm{TR}}}}$

Wherein χ _sR=α ² _sR, χ _tR=α ² _tR, and definition calculates W _s, W _rwith W _tformula be convex optimizing power distribution formula;

Step 2: via node (R) is according to repeat transmitted power W _rsend information to the first source node (S) and the second source node (T), via node (R) is by transmitting power W simultaneously _sdata value sends described first source node (S) to, tells that the first source node (S) adopts W _sperformance number carry out message transmission, via node (R) is by transmitting power W _tdata value sends described second source node (T) to, tells that the second source node (T) adopts W _tperformance number carry out message transmission;

Step 3: in the communication process of described single relayed communications network inside:

Described first source node (S) is always according to the first transmitting power W _stransmission information is to via node (R), until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described second source node (T) is always according to the second transmitting power W _ttransmission information is to via node (R), until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then return execution step 2;

Described via node (R) is always according to repeat transmitted power W _rinformation is sent to the first source node (S) and the second source node (T), until channel condition information changes, via node according to convex optimizing power distribution formula, will recalculate the best transmit power of each node, then returns execution step 2.