CN103269488B - Based on maximum and speed collaborative communication method in cognition wireless network - Google Patents

Abstract

The invention provides based on maximum and speed collaborative communication method in a kind of cognition wireless network, this new communication for coordination scheme with maximize in cognition wireless network primary and secondary user's and speed.By modeling, primary and secondary user's and speed maximization problems are expressed as combinatorial optimization problem, then auxiliary variable is introduced, required problem equivalent is converted into the standard assignments problem in operational research, and according to this Solving Assignment Problem algorithm, it is proposed that based on the primary and secondary synergic user communication scheme of Hungary Algorithm.Cognition wireless network is when adopting AF, DF communication for coordination and the direct communication mode of the present invention by contrast, primary and secondary user in varied situations and speed situation of change.Simulation result shows, when secondary number of users is more, adopts the communication for coordination scheme of the present invention to bring and the lifting of speed more than 1.3 times, meanwhile, AF communication for coordination than DF cooperative communication mode be particularly suited in cognition wireless network with improve primary and secondary user's and speed.

Description

Based on maximum and speed collaborative communication method in cognition wireless network

Technical field

A kind of method that the present invention relates to cognition wireless network technical field, specifically based on maximum and speed a kind of communication for coordination scheme in cognition wireless network.

Background technology

Cognition wireless network is a crucial application technology for alleviating frequency spectrum resource scarcity problem.This network exists two kinds of users, a kind of paying customer or authorized user being to use at any time certain channel, is commonly referred to primary user；Another kind is the authorization channel being absent from oneself, only by the secondary user searched for and use the channel not taken completely by primary user in surrounding space to communicate.Secondary user realizes coexisting by different communication modes from primary user, drastically increases the utilization rate of wireless frequency spectrum.And study the key with Design cognition wireless network, it is simply that realize time user and coexist with the optimum of primary user.

Akyildiz et al. is at " ComputerNetworks, 2006,50 (13): 2127-2159 " article being entitled as " Nextgeneration/dynamicspectrumaccess/cognitiveradiowirel essnetworks:asurvey " has been delivered on.This article system elaborate the Coexistence mode of primary and secondary user in various traditional cognition wireless network.But, in these primary and secondarys user's Coexistence mode, secondary user has simply used the idle channel being absent from primary user, fails to form fully cooperation or interactive with primary user, result in system and the combination property such as speed low.Existing lot of documents is used for studying time user and primary user's symbiont techn problem at present.

DNiyato et al. is at " IEEETrans.MobileComputing, 2009,8 (8): 1009-1022 " article being entitled as " Dynamicsofmultiple-sellerandmultiple-buyerspectrumtradin gincognitiveradionetworks:Agame-theoreticmodelingapproac h " has been delivered on；SK.Jayaweera et al. is at " IEEETrans.WirelessCommunications, 2009,8 (6): 3300-3310 " article being entitled as " Dynamicspectrumleasingincognitiveradionetworksviaprimary-secondaryuserpowercontrolgames " has been delivered on；HYu et al. has delivered, on " IEEETrans.Vehicular.tchnology, 2010,59 (4): 1769-1778 ", the article being entitled as " PricingforUplinkPowerControlinCognitiveRadioNetworks ".These articles, based on game theory, consider coexisting of primary and secondary user from the angle of maximum revenue: secondary user is accessed produced jamming power and quantifies by primary user, and it is charged.So, the access power of secondary user is more high, and the cost paid is also more high.Under considering the maximized situation of respective total revenue, primary and secondary user passes through game, it is achieved coexist.But, this mechanism is not only suitable for primary user needs the situation of higher data rate, remains without the collaborative problem considering primary and secondary user simultaneously.

Some researchs are attempted the concept of communication for coordination is introduced cognition wireless network, to solve the collaborative problem of primary and secondary user.The user of communication for coordination feeling the pulse with the finger-tip forms a virtual aerial array by multi-user's cooperation or completes the technology of communication by multi-user's relay forwarding information, so, communication for coordination has the multiple advantage such as space diversity, trunking traffic concurrently simultaneously, can effectively overcome channel fading, improve communication quality.

YHan et al. has delivered, on " IEEETrans.WirelessCommunication, 2009,8 (10): 4945-4950 ", the article being entitled as " Cooperativedecode-andforwardrelayingforsecondaryspectrum access "；L.Giupponi et al. has delivered the article being entitled as " Distributedcooperationamongcognitiveradioswithcompletean dincompleteinformation " on " EURASIPJournalonAdvancesinSignalProcessing, 2009 ".These articles consider and distribute the Partial Power situation for assisting primary user to transmit from secondary user.Simeone et al. is at " SelectedAreasinCommunications, IEEEJournal, 2008,26 (1): 203-213 " article being entitled as " Spectrumleasingtocooperatingsecondaryadhocnetworks " has been delivered on, each transmission time slot is divided into 3 sections by this article, it is respectively used to primary user's transmission, secondary user collaborative primary user transmission and secondary user transmission, but this article has simply assumed that the situation of single channel (a pair primary user).SBayat et al. is at " Communications (ICC), 2011IEEEInternationalConference, 2011,: 1-6 " on delivered the article being entitled as " CognitiveRadioRelayNetworkswithMultiplePrimaryandSeconda ryUsers:DistributedStableMatchingAlgorithmsforSpectrumAc cess ", the research of Simeone et al. has been extended by this article, it is contemplated that multi channel situation.But, the scheme in above each document does not all account for the virtual condition of channel when carrying out communication for coordination, simultaneously also without considering that time user communication itself is likely to the lifting of network and the speed brought.

In order to solve the problems referred to above, the present invention proposes a kind of new primary and secondary synergic user communication scheme.When multichannel many primary users, the present invention establishes primary user according to respective channel status, opportunistic select direct communication mode or have secondary user to do the cooperative communication mode relayed, communication time user is allowed rationally to select available channel, to maximize the model of primary and secondary telex network and speed in each time slot.Further by introducing auxiliary variable, this combinatorial optimization problem is converted for the standard assignments problem in operational research theory, and gives the primary and secondary synergic user communication scheme of the derivation algorithm Hungary Algorithm based on standard assignments problem.Simulation result shows, when secondary number of users is more, compared to other scheme, the present invention can bring cognition wireless network and the lifting of speed more than 1.3 times.

Summary of the invention

It is an object of the invention to overcome the deficiency on existing research and technology, the present invention proposes in cognition wireless network based on maximum and speed a kind of communication for coordination scheme.In the present invention, primary user selects the whether collaborative own data transmission of time user by chance, allows secondary user of communication maximizes cognition wireless network by coupling best available and speed.By modeling, this and speed maximization problems being represented a combinatorial optimization problem, be further introduced into auxiliary variable, problem being converted for a standard assignments problem of equal value, thus proposing the communication for coordination scheme based on Hungary Algorithm.Simulation result shows, the more traditional direct communication plan not adopting communication for coordination of the present invention significantly improve primary and secondary user's and speed.

The present invention is achieved through the following technical solutions:

Based on maximum and speed collaborative communication method in described cognition wireless network, comprise the following steps:

The first step: when each time slot starts, control station obtains network parameter, and network parameter includes the channel gain of each channel and Background Noise Power, and the channel gain of each channel includes the channel gain between the corresponding transceiver of expression respectivelyWherein S_i、D_iRepresent the primary user's transmitter on i-th channel and receiver, R respectively_j、RD_jRepresent the secondary user transmitter on j-th strip channel and receiver respectively, correspondingly,Represent the channel gain between primary user's transmitter and the primary user's receiver on i-th channel,Represent the channel gain between the primary user's transmitter on i-th channel and the secondary user transmitter on j-th strip channel,Represent the channel gain between secondary user transmitter and the primary user's receiver on i-th channel on j-th strip channel,Represent the channel gain between secondary user transmitter and the secondary receiver user on j-th strip channel；

Meanwhile, control station also obtains the channel width w of i-th channel_i, 1≤i≤M, and Background Noise Power；

Second step: calculate all primary and secondary users traffic rate at each channel according to the network parameter in the first step；

3rd step: calculate the intermediate parameters used needed for Hungary Algorithm；Intermediate parameters is matrix B, B=(b_i,j)_(M+N)×(M+N), b_i,jThe element of representing matrix B, B_max=max (b_i,j)；

Wherein each element of matrix B is:

Wherein C_{i,j_coop}Represent the channel capacity of primary and secondary synergic user communication, C_{i_dir}Represent the channel capacity that primary user directly communicates, C_{i,j_sec}Representing that time user is to i channel capacity of directly communication on channel j, M represents the number of available channel, and N represents the number of time user, P represents the number of users having communication requirement in primary user, for simplicity in this formula, set the number of users as there being communication requirement of front P the user in primary user

Namely the dimension form of B is as follows:

$B=\left[\begin{array}{ccc}{A}_{P\×N}& D_{P\×P}& 0_{P\×(M-P)}\\ C_{(M-P)\×N}& 0_{(M-P)\×P}& 0_{(M-P)\×(M-P)}\\ 0_{N\×N}& 0_{N\×P}& 0_{N\×(M-P)}\end{array}\right]$

Wherein A_P×NRepresent the matrix of P × N dimension, C_(M-P)×NRepresent the matrix of (M-P) × N dimension, D_P×PRepresent the matrix of P × P dimension；

4th step: adopt Hungarian Method and matrix Y, the y corresponding to final communication plan_i,jThe element of representing matrix Y；

Each element of matrix Y is:

$y_{i,j}=\left\{\begin{array}{cc}{y}_{i,j}=x_{i,j}& ;1\≤i\≤M,1\≤j\≤N\\ \underset{i=1}{\overset{M}{\mathrm{\Σ}}}{y}_{i,j}+\underset{i=M+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\\ \underset{j=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,j}+\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\end{array}\right.$

Wherein, algebraically 1 represent at most only 1 user can as trunk subscriber or secondary user as trunk subscriber time can only service at most 1 primary user, x_i,jRepresent the auxiliary variable in mathematical derivation process, x_i,jPhysical significance as follows:

As 1≤i≤P, 1≤j≤N,

As P+1≤i≤M, 1≤j≤N,

Wherein P represents the number of users having communication requirement in primary user, for simplicity in this formula, sets the number of users as there being communication requirement of front P the user in primary user；

5th step: each element value according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method.

Preferably, in described second step, calculate C by shannon formula with communication for coordination channel capacity formula_{i_dir},C_{i,j_coop},C_{i,j_sec},

Concrete calculating process is:

$C_{i\_\mathrm{dir}}=w_i{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i})$

Wherein,

${\mathrm{SNR}}_{S_i{D}_i}={\left|a_{S_i{D}_i}\right|}^2{P}_{S_i}/N_{S_i{D}_i}$

WhereinRepresent that primary user is to S_i、D_iSignal to noise ratio when transmitting on channel i, w_iRepresent the channel width of i-th channel,Represent the transmitting power of primary user i；Represent the Background Noise Power on channel i；For representing the channel coefficients of yardstick decline, define as follows:

$a_{S_i{D}_i}=h_{S_i{D}_i}/d_i^{v/2}$

Wherein d_iRepresent the distance between i-th pair primary user's transmitter and receiver；V represents variable channel fading factor；

During the half-duplex DF mode of the time-division slots such as employing, the channel capacity C of primary and secondary synergic user communication_{i,j_coop}For:

$C_{i,j\_\mathrm{coop}}=w_i\min \{\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{R}_j}),\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i}+{\mathrm{SNR}}_{R_j{D}_i})\}$

WhereinRepresent the signal to noise ratio between primary user's transmitting terminal and trunk subscriber transmitting terminal,Represent the signal to noise ratio between primary user's transmitting terminal and primary user's receiving terminal,Represent the signal to noise ratio between trunk subscriber transmitting terminal and primary user's receiving terminal；

During the half-duplex AF mode of the time-division slots such as employing, the channel capacity C of primary and secondary synergic user communication_{i,j_coop}For:

$C_{i,j\_\mathrm{coop}}=\frac{1}{2}{w}_i{\log }_2(1+\frac{{\left|a_{S_i{D}_j}\right|}^2{P}_{S_i}}{N_{S_i{D}_i}}+\frac{{\left|a_{S_i{R}_j}\right|}^2{\left|a_{R_j{D}_i}\right|}^2{\left|{\mathrm{\β}}_{i,j}\right|}^2{P}_{S_i}}{N_{R_i{D}_j}+{\left|a_{R_i{D}_j}\right|}^2{\left|{\mathrm{\β}}_{i,j}\right|}^2{N}_{S_i{R}_j}})$

In above formula,

${\mathrm{\β}}_{i,j}=P_{R_j}/(P_{S_i}{\left|a_{S_i{D}_i}\right|}^2+N_{S_i{D}_i})$

Wherein,For representing the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and receiving terminal,Represent the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and i-th trunk subscriber transmitting terminal,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and i-th time user's receiving terminal,Represent the Background Noise Power between trunk subscriber transmitting terminal and primary user's receiving terminal on channel i,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and jth time user's receiving terminal,Represent the Background Noise Power between primary user's transmitting terminal and trunk subscriber transmitting terminal on channel i,Represent the transmitting power of jth trunk subscriber,Represent the Background Noise Power between main transmitting terminal and receiving terminal on channel i,Represent the transmitting power of primary user i；

C_{i,j_sec}Computing formula and C_{i_dir}Computing formula principle identical, particularly as follows:

$C_{i,j\_\sec }=w_i{\log }_2(1+{\mathrm{SNR}}_{j{R}_{i}R{D}_i})$

Wherein,

${\mathrm{SNR}}_{{\mathrm{jR}}_i{\mathrm{RD}}_i}={\left|a_{R_{i}R{D}_i}\right|}^2{P}_{R{S}_i}/N_{j{R}_{i}R{D}_i}$

WhereinRepresent that time user is to R_i、RD_iSignal to noise ratio when transmitting on channel j, w_jRepresent the channel width of j-th strip channel,Represent the transmitting power of time user i；Represent the Background Noise Power on channel j；For representing the channel coefficients of yardstick decline, define as follows:

$a_{R_i{\mathrm{RD}}_i}=h_{R_i{\mathrm{RD}}_i}/d_{\text{i}}^{v/2}$

Wherein d_iRepresent the i-th pair time distance between user transmitter and receiver；V represents variable channel fading factor；R_i、RD_iRepresent the secondary user transmitter on i-th channel and receiver respectively；Represent the channel gain between secondary user transmitter and the receiver on i-th channel.

Preferably, each element value in described 5th step, according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method, specifically, as 1≤i≤P, 1≤j≤N, if y_i,j=1, the communication for coordination between primary and secondary user is selected in algebraically 1 namely expression, then primary user i selects time user j to carry out communication for coordination；As P+1≤i≤M, 1≤j≤N, if y_i,j=1, algebraically 1 namely allow communication between time user, then secondary user j uses channel i to communicate.

According to an aspect of the present invention, it is provided that based on maximum and speed a kind of communication for coordination scheme in cognition wireless network, comprise the following steps:

The first step: when each time slot starts, control station obtains the network of relation parameters such as the channel gain of each channel, Background Noise Power；

Second step: calculate all primary and secondary users traffic rate at each channel according to the network of relation parameter in the first step；

3rd step: calculate the intermediate parameters used needed for Hungary Algorithm；

4th step: adopt the matrix Y that Hungarian Method is corresponding；

5th step: each element value according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method.

More specifically, the present invention realizes preferably by techniques below scheme and step:

The first step: when each time slot starts, control station obtains the network of relation parameters such as the channel gain of each channel, Background Noise Power.Including the channel gain represented respectively between corresponding transceiverWherein S_i、D_iRepresent the primary user's transmitter on i-th channel and receiver, R respectively_j、RD_jRepresent the secondary user transmitter on j-th strip channel and receiver.Meanwhile, acquired parameter also includes the bandwidth w of i-th channel_i, 1≤i≤M, Background Noise Power etc..

Second step: calculate all primary and secondary users traffic rate at each channel according to the network of relation parameter in the first step.Following calculation is had with the traffic rate of relay cooperative communication preferably for the directly traffic rate of communication not using relaying:

According to Shannon's theorems, i-th pair primary user does not select time user to relay on channel i, and when directly communicating, its transfer rate is:

$C_{i\_\mathrm{dir}}=w_i{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i})$

Wherein,

${\mathrm{SNR}}_{S_i{D}_i}={\left|a_{S_i{D}_i}\right|}^2{P}_{S_i}/N_{S_i{D}_i}$

Represent that primary user is to S_i、D_iSignal to noise ratio when transmitting on channel i, w_iRepresent the channel width of i-th channel.In above formulaRepresent the transmitting power of primary user i；Represent the Background Noise Power on channel i；For representing the channel coefficients of yardstick decline, define as follows:

$a_{S_i{D}_i}=h_{S_i{D}_i}/d_i^{v/2}$

Wherein d_iRepresent the distance between i-th pair primary user's transmitter and receiver；V represents variable channel fading factor.

When i-th pair primary user selects certain user j to carry out communication for coordination as relaying on channel i, the difference according to trunking scheme, its speed has different computational methods.During the half-duplex DF mode of the time-division slots such as employing, the transfer rate C of primary user i_{i,j_coop}For:

$C_{i,j\_\mathrm{coop}}=w_i\min \{\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{R}_j}),\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i}+{\mathrm{SNR}}_{R_j{D}_i})\}$

WhereinRepresent the signal to noise ratio between primary user's transmitting terminal and trunk subscriber transmitting terminal,Represent the signal to noise ratio between primary user's transmitting terminal and primary user's receiving terminal,Represent the signal to noise ratio between trunk subscriber transmitting terminal and primary user's receiving terminal.

During the half-duplex AF mode of the time-division slots such as employing, the transfer rate C of primary user i_{i,j_coop}For:

$C_{i,j\_\mathrm{coop}}=\frac{1}{2}{w}_i{\log }_2(1+\frac{{\left|a_{S_i{D}_j}\right|}^2{P}_{S_i}}{N_{S_i{D}_i}}+\frac{{\left|a_{S_i{R}_j}\right|}^2{\left|a_{R_j{D}_i}\right|}^2{\left|{\mathrm{\β}}_{i,j}\right|}^2{P}_{S_i}}{N_{R_i{D}_j}+{\left|a_{R_i{D}_j}\right|}^2{\left|{\mathrm{\β}}_{i,j}\right|}^2{N}_{S_i{R}_j}})$

In above formula,

${\mathrm{\β}}_{i,j}=P_{R_j}/(P_{S_i}{\left|a_{S_i{D}_i}\right|}^2+N_{S_i{D}_i})$

Wherein,For representing the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and receiving terminal,Represent the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and i-th trunk subscriber transmitting terminal,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and i-th time user's receiving terminal,Represent the Background Noise Power between trunk subscriber transmitting terminal and primary user's receiving terminal on channel i,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and jth time user's receiving terminal,Represent the Background Noise Power between primary user's transmitting terminal and trunk subscriber transmitting terminal on channel i,Represent the transmitting power of jth trunk subscriber,Represent the Background Noise Power between main transmitting terminal and receiving terminal on channel i.

C_{i,j_sec}Computing formula and C_{i_dir}Computing formula principle identical, particularly as follows:

$C_{i,j\_\sec }=w_i{\log }_2(1+{\mathrm{SNR}}_{j{R}_{i}R{D}_i})$

Wherein,

${\mathrm{SNR}}_{{\mathrm{jR}}_i{\mathrm{RD}}_i}={\left|a_{R_{i}R{D}_i}\right|}^2{P}_{R{S}_i}/N_{j{R}_{i}R{D}_i}$

WhereinRepresent that time user is to R_i、RD_iSignal to noise ratio when transmitting on channel j, w_jRepresent the channel width of j-th strip channel,Represent the transmitting power of time user i；Represent the Background Noise Power on channel j；For representing the channel coefficients of yardstick decline, define as follows:

$a_{R_i{\mathrm{RD}}_i}=h_{R_i{\mathrm{RD}}_i}/d_{\text{i}}^{v/2}$

Wherein d_iRepresent the i-th pair time distance between user transmitter and receiver；V represents variable channel fading factor；When taking other different trunking traffic mode, only need to calculate by respective traffic rate computing formula.It is therefore preferred that calculate C by shannon formula with communication for coordination channel capacity formula_{i_dir},C_{i,j_coop},C_{i,j_sec}。

3rd step: calculate the intermediate parameters used needed for Hungary Algorithm；

Preferably, Hungary Algorithm is used to solve in a cognition wireless network about the standard assignments problem maximizing primary and secondary user and problem rate.Its concrete solution procedure is as follows:

If U_i, 1≤i≤M represents the transfer rate of i-th pair primary user, and M represents the number of available channel namely the number of primary user；V_i, 1≤i≤N represents the transfer rate of i-th pair time user, and N represents the number of time user.And U_i,V_iDefine as follows:

Then primary and secondary user and speed maximization problems are:

$\max S=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{U}_i+\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{V}_i$

Wherein, S is for representing primary and secondary user and the maximized object function of speed.

Satisfy condition: primary user can use its authorization channel to communicate at any time, and secondary user only just can communicate at the channel of dereliction CU.

Primary communicating by identical probability per family due to all, might as well assume in certain time slot, front P the user in M primary user needs to communicate.Define new auxiliary variable as follows simultaneously:

As 1≤i≤P, 1≤j≤N,

As P+1≤i≤M, 1≤j≤N,

Wherein, x_i,jRepresenting the auxiliary variable in mathematical derivation process, its physical significance is as shown in its definition.

So, former problem and restrictive condition thereof can be converted into following problems:

$\max S=\max (\underset{i=1}{\overset{P}{\mathrm{\Σ}}}{U}_i+\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{V}_i)$

$=\underset{i=1}{\overset{P}{\mathrm{\Σ}}}\{\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(x_{i,j}\·C_{i,j\_\mathrm{coop}})+[(1-\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{x}_{i,j})\·C_{i\_\mathrm{dir}}\left]\right\}$

$+\underset{i=P+1}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}\left(x_{i,j}{C}_{i,j\_\sec }\right)$

Satisfy condition:

Above-mentioned two restrictive condition is used for guaranteeing that each primary user at most can only select one user, each user at most can only service a primary user and carry out communication for coordination；Meanwhile, the problem after second restrictive condition substitution being converted will also realize that, communication primary user or selection directly communicate or select communication for coordination, and in a word, the communication requirement of primary user is met.

For solving the problems referred to above, now define following two matrix B=(b_i,j)_(M+N)×(M+N)With Y=(y_i,j)_(M+N)×(M+N), wherein, b_i,jThe element of representing matrix B, y_i,jThe element of representing matrix Y.Each element of matrix B is:

Namely the form of B is as follows:

$B=\left[\begin{array}{ccc}{A}_{P\×N}& D_{P\×P}& 0_{P\×(M-P)}\\ C_{(M-P)\×N}& 0_{(M-P)\×P}& 0_{(M-P)\×(M-P)}\\ 0_{N\×N}& 0_{N\×P}& 0_{N\×(M-P)}\end{array}\right]$

Each element of matrix Y is:

$y_{i,j}=\left\{\begin{array}{cc}{y}_{i,j}=x_{i,j}& ;1\≤i\≤M,1\≤j\≤N\\ \underset{i=1}{\overset{M}{\mathrm{\Σ}}}{y}_{i,j}+\underset{i=M+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\\ \underset{j=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,j}+\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\end{array}\right.$

Then above-mentioned object function can be converted into:

$S=\underset{i=1}{\overset{P}{\mathrm{\Σ}}}\{\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(x_{i,j}\·C_{i,j\_\mathrm{coop}})+[(1-\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{x}_{i,j})\·C_{i\_\mathrm{dir}}\left]\right\}+\underset{i=P+1}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}\left(x_{i,j}{C}_{i,j\_\sec }\right)$

$=\underset{i=1}{\overset{P}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})+\underset{i=1}{\overset{P}{\mathrm{\Σ}}}[\left(\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}\right)\·C_{i\_\mathrm{dir}}]+0+\underset{i=P+1}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})$

$=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})+\underset{i=1}{\overset{M}{\mathrm{\Σ}}}(\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}\·b_{i,j})+0+0$

$=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})+\underset{i=1}{\overset{M}{\mathrm{\Σ}}}(\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}\·b_{i,j})+\underset{i=M}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})+\underset{i=M}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})$

$=\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})$

If B_max=max (b_i,j), and make a_i,j=B_max-b_i,j, then above formula can abbreviation be further:

$\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·b_{i,j})=\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}[y_{i,j}\·(B_{\max }-a_{i,j})]$

$=\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·B_{\max })-\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·a_{\text{i,j}})$

$=(M+N)\·B_{\max }-\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·a_{i,j})$

Therefore former problem can be answered by solving following minimization problem:

$\min F=\underset{i=1}{\overset{M+N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}(y_{i,j}\·a_{i,j})$

Satisfy condition:

$\underset{j=1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1;i=\mathrm{1,2},...,M+N$

Wherein, function F represents an intermediate function, and the meaning of this function is in that conveniently to solve former problem function.

Above-mentioned minimization problem is the assignment problem of standard on operational research, it is possible to solved by Hungary Algorithm.It is therefore preferred that the required parameter calculated is in this step: matrix B, B_max=max (b_i,j)。

Preferably, each element of matrix B is:

Namely the form of B is as follows:

$B=\left[\begin{array}{ccc}{A}_{P\×N}& D_{P\×P}& 0_{P\×(M-P)}\\ C_{(M-P)\×N}& 0_{(M-P)\×P}& 0_{(M-P)\×(M-P)}\\ 0_{N\×N}& 0_{N\×P}& 0_{N\×(M-P)}\end{array}\right]$

4th step: adopt the matrix Y that Hungarian Method is corresponding；Preferably, each element of matrix Y is:

$y_{i,j}=\left\{\begin{array}{cc}{y}_{i,j}=x_{i,j}& ;1\≤i\≤M,1\≤j\≤N\\ \underset{i=1}{\overset{M}{\mathrm{\Σ}}}{y}_{i,j}+\underset{i=M+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\\ \underset{j=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,j}+\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\end{array}\right.$

5th step: each element value according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method.Preferably, as 1≤i≤P, 1≤j≤N, if y_i,j=1, then primary user i selects time user j to carry out communication for coordination；As P+1≤i≤M, 1≤j≤N, if y_i,j=1, then secondary user j uses channel i to communicate.

Accompanying drawing explanation

Fig. 1 is the cognition wireless network model having some primary users with time user；

Fig. 2 is three kinds of different communication mode lower network and speed and time number of users relation；

Fig. 3 is three kinds of different communication mode lower network and speed and Between Signal To Noise Ratio.

Detailed description of the invention

Below in conjunction with accompanying drawing, embodiments of the invention are elaborated: the present embodiment is carried out under premised on technical solution of the present invention, give detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

In instances, the present invention has contrasted with the direct communication mode not using relaying to carry out communication for coordination, and meanwhile, the present invention also compared for the two kinds of cooperative communication modes of AF, DF performance difference in communication for coordination of the present invention.

Embodiment

The present embodiment is the cognition wireless network that primary and secondary user's random distribution as shown in Figure 1 ranges for 1km × 1km.The network when cognition wireless network of relative analysis herein adopts AF, DF communication for coordination of the present invention with direct communication mode and speed are with secondary number of users and signal to noise ratio variation relation.In order to contrast for the purpose of justice, when network adopts direct communication mode, the present invention only allows the secondary user that can bring maximum channel speed to be transmitted taking available channel.Meanwhile, in simulation analysis, the present invention takes spatial fading factor v=3, and all simulation results are all on average obtained by the cognition wireless network acquired results of 10000 random distributions under specific settings.Being embodied as step is:

The first step: when each time slot starts, control station obtains the network of relation parameters such as the channel gain of each channel, Background Noise Power.Including the channel gain represented respectively between corresponding transceiverWherein S_i、D_iRepresent the primary user's transmitter on i-th channel and receiver, R respectively_j、RD_jRepresent the secondary user transmitter on j-th strip channel and receiver, the above-mentioned equal Rayleigh distributed of each channel gain and E [| h_ij|²]=1.Meanwhile, it is w that acquired parameter also includes the bandwidth of i-th channel_i=1kHz, 1≤i≤M；The Background Noise Power of each channel is equal in magnitude, unless stated otherwise, and background noise power levels equal 10^-6mW；The transmitting power of each primary user and time user is 1mW；In each time slot, primary user takies the probability of its authorization channel is 0.7 etc.；

Second step: calculate all primary and secondary users traffic rate at each channel according to the network of relation parameter in the first step.Preferably, C is calculated by shannon formula with communication for coordination channel capacity formula_{i_dir},C_{i,j_coop},C_{i,j_sec}；

3rd step: calculate the intermediate parameters used needed for Hungary Algorithm.Preferably, the intermediate parameters of calculating is: matrix B, B_max=max (b_i,j)；

Preferably, each element of matrix B is:

Namely the form of B is as follows:

$B=\left[\begin{array}{ccc}{A}_{P\×N}& D_{P\×P}& 0_{P\×(M-P)}\\ C_{(M-P)\×N}& 0_{(M-P)\×P}& 0_{(M-P)\×(M-P)}\\ 0_{N\×N}& 0_{N\×P}& 0_{N\×(M-P)}\end{array}\right]$

4th step: adopt the matrix Y that Hungarian Method is corresponding；Preferably, each element of matrix Y is:

$y_{i,j}=\left\{\begin{array}{cc}{y}_{i,j}=x_{i,j}& ;1\≤i\≤M,1\≤j\≤N\\ \underset{i=1}{\overset{M}{\mathrm{\Σ}}}{y}_{i,j}+\underset{i=M+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\\ \underset{j=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,j}+\underset{j=N+1}{\overset{M+N}{\mathrm{\Σ}}}{y}_{i,j}=1& ;i=\mathrm{1,2},\·\·\·,M+N\end{array}\right.$

5th step: each element value according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method.Preferably, as 1≤i≤P, 1≤j≤N, if y_i,j=1, then primary user i selects time user j to carry out communication for coordination；As P+1≤i≤M, 1≤j≤N, if y_i,j=1, then secondary user j uses channel i to communicate.

When Fig. 2 represents M=10, SNR=60dB, under three kinds of communication modes, primary and secondary user and speed are with the variation relation of secondary number of users.As seen from the figure, along with secondary number of users increases, the distance between primary user and available collaborative user becomes near, and the maximum channel speed of communication time user couple also can increase simultaneously, thus under three kinds of communication modes primary and secondary user's and speed all increase；Can be seen that, communication for coordination scheme of the present invention brings and being obviously improved of speed simultaneously, and this is owing to the invention enables different primary user to according to each channel conditions, have selected, with the two ways that directly communicates, the communication mode that speed is bigger in communication for coordination；Furthermore, all available channels have also been distributed on the secondary user couple that traffic rate is maximum, ensure that the maximization of whole network primary and secondary user and speed.Be will also realize that by figure, compared to DF communication for coordination with directly communicate, the speed that under AF cooperative communication mode, primary and secondary user and speed increase with secondary number of users is faster；During N=27, AF cooperative communication mode lower network is that DF works in coordination with and 1.35,1.67 times under direct communication mode with speed respectively, this is because, when only considering channel speed, the rate-constrained of DF cooperative communication mode is in SR link and RD, worst in SD link one, AF cooperative communication mode is not then individually limited to SR, RD, a certain bar link in SD, even if a certain bar link circuit condition is poor, when other link circuit condition is better, still can obtain bigger speed.

When Fig. 3 represents M=10, N=20, under three kinds of different communication modes primary and secondary user's and speed with the variation relation of channel SNRs, in emulation, the transmitting power of the fixing primary and secondary user of the present invention, changes Background Noise Power gradually.As seen from the figure, rising along with signal to noise ratio, the communication quality of each channel improves, three kinds of communication modes all can bring the rising with speed, the two kinds of communication for coordination schemes of DF, AF based on Hungary Algorithm carried are superior to direct communication plan, and AF communication for coordination remains and can bring maximum and speed communication mode, its reason is analyzed similar with Fig. 2.When SNR=68dB, it is DF mode and the 1.37 of direct communication mode, 1.74 times respectively with speed under AF mode.Will also realize that in conjunction with Fig. 2, Fig. 3, under the target of maximization network and speed, AF communication for coordination scheme relatively DF communication for coordination scheme is more suitably applied in cognition wireless network.

Above specific embodiments of the invention are described.It is to be appreciated that the invention is not limited in above-mentioned particular implementation, those skilled in the art can make various deformation or amendment within the scope of the claims, and this has no effect on the flesh and blood of the present invention.

Claims (2)

1. based on maximum and speed collaborative communication method in a cognition wireless network, it is characterised in that comprise the following steps:

The first step: when each time slot starts, control station obtains network parameter, and network parameter includes the channel gain of each channel and Background Noise Power, and the channel gain of each channel includes the channel gain between the corresponding transceiver of expression respectivelyWherein S_i、D_iRepresent the primary user's transmitter on i-th channel and receiver, R respectively_j、RD_jRepresent the secondary user transmitter on j-th strip channel and receiver respectively, correspondingly,Represent the channel gain between primary user's transmitter and the primary user's receiver on i-th channel,Represent the channel gain between the primary user's transmitter on i-th channel and the secondary user transmitter on j-th strip channel,Represent the channel gain between secondary user transmitter and the primary user's receiver on i-th channel on j-th strip channel,Represent the channel gain between secondary user transmitter and the secondary receiver user on j-th strip channel；

Meanwhile, control station also obtains the channel width w of i-th channel_i, 1≤i≤M, and Background Noise Power；

Second step: calculate all primary and secondary users traffic rate at each channel according to the network parameter in the first step；

3rd step: calculate the intermediate parameters used needed for Hungary Algorithm；Intermediate parameters is matrix B, B=(b_i,j)_(M+N)×(M+N), b_i,jThe element of representing matrix B, B_max=max (b_i,j)；

Wherein each element of matrix B is:

Wherein C_{i,j_coop}Represent the channel capacity of primary and secondary synergic user communication, C_{i_dir}Represent the channel capacity that primary user directly communicates, C_{i,j_sec}Represent that time user is to i channel capacity of directly communication on channel j, the secondary user user couple to representing that the secondary user transmitter communicated and time receiver user are constituted, M represents the number of available channel, N represents the number of time user, P represents the number of users having communication requirement in primary user, for simplicity in this formula, set the number of users as there being communication requirement of front P the user in primary user

Namely the dimension form of B is as follows:

$B=\left[\begin{array}{ccc}{A}_{P\×N}& D_{P\×P}& 0_{P\×(M-P)}\\ C_{(M-P)\×N}& 0_{(M-P)\×P}& 0_{(M-P)\×(M-P)}\\ 0_{N\×N}& 0_{N\×P}& 0_{N\×(M-P)}\end{array}\right]$

Wherein A_P×NRepresent the matrix of P × N dimension, C_(M-P)×NRepresent the matrix of (M-P) × N dimension, D_P×PRepresent the matrix of P × P dimension；

4th step: adopt Hungarian Method and matrix Y, the y corresponding to final communication plan_i,jThe element of representing matrix Y；

Each element of matrix Y is:

$y_{i,j}=\left\{\begin{array}{cc}{y}_{i,j}=x_{i,j};& 1\≤i\≤M,1\≤j\≤N\\ \underset{i=1}{\overset{M}{\Σ}}{y}_{i,j}+\underset{i=M+1}{\overset{M+N}{\Σ}}{y}_{i,j}=1;& i=1,2,...,M+N\\ \underset{j=1}{\overset{N}{\Σ}}{y}_{i,j}+\underset{j=N+1}{\overset{M+N}{\Σ}}{y}_{i,j}=1;& i=1,2,...,M+N\end{array}\right.$

Wherein, algebraically 1 represent at most only 1 user can as trunk subscriber or secondary user as trunk subscriber time can only service at most 1 primary user, x_i,jRepresent the auxiliary variable in mathematical derivation process, x_i,jPhysical significance as follows:

As 1≤i≤P, 1≤j≤N,

As P+1≤i≤M, 1≤j≤N,

Wherein P represents the number of users having communication requirement in primary user, for simplicity in this formula, sets the number of users as there being communication requirement of front P the user in primary user；

5th step: each element value according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method；

Each element value in described 5th step, according to matrix Y, it is determined that the communication mode of each primary and secondary user and working method, particularly as follows:

As 1≤i≤P, 1≤j≤N, if y_i,j=1, the communication for coordination between primary and secondary user is selected in algebraically 1 namely expression, then primary user i selects time user j to carry out communication for coordination；

As P+1≤i≤M, 1≤j≤N, if y_i,j=1, algebraically 1 namely allow communication between time user, then secondary user j uses channel i to communicate.

2. based on maximum and speed collaborative communication method in cognition wireless network according to claim 1, it is characterized in that, in described second step, calculate C by shannon formula with communication for coordination channel capacity formula_{i_dir},C_{i,j_coop},C_{i,j_sec},

Concrete calculating process is:

$C_{i\_dir}=w_i{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i})$

Wherein,

${\mathrm{SNR}}_{S_i{D}_i}=|a_{S_i{D}_i}{|}^2{P}_{S_i}/N_{S_i{D}_i}$

WhereinRepresent that primary user is to S_i、D_iSignal to noise ratio when transmitting on channel i, w_iRepresent the channel width of i-th channel,Represent the transmitting power of primary user i；Represent the Background Noise Power on channel i；For representing the channel coefficients of yardstick decline, define as follows:

$a_{S_i{D}_i}=h_{S_i{D}_i}/d_i^{v/2}$

Wherein d_iRepresent the distance between i-th pair primary user's transmitter and receiver；V represents variable channel fading factor；

During the half-duplex DF mode of the time-division slots such as employing, the channel capacity C of primary and secondary synergic user communication_{i,j_coop}For:

$C_{i,j\_coop}=w_i\min \{\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{R}_j}),\frac{1}{2}{\log }_2(1+{\mathrm{SNR}}_{S_i{D}_i}+{\mathrm{SNR}}_{R_j{D}_i})\}$

WhereinRepresent the signal to noise ratio between primary user's transmitting terminal and trunk subscriber transmitting terminal,Represent the signal to noise ratio between primary user's transmitting terminal and primary user's receiving terminal,Represent the signal to noise ratio between trunk subscriber transmitting terminal and primary user's receiving terminal；

During the half-duplex AF mode of the time-division slots such as employing, the channel capacity C of primary and secondary synergic user communication_{i,j_coop}For:

$C_{i,j\_coop}=\frac{1}{2}{w}_i{\log }_2(1+\frac{|a_{S_i{D}_j}{|}^2{P}_{S_i}}{N_{S_i{D}_i}}+\frac{\left|a_{S_i{R}_j}{|}^2\right|a_{R_j{D}_i}{|}^2|{\mathrm{\β}}_{i,j}{|}^2{P}_{S_i}}{N_{R_i{D}_j}+\left|a_{R_i{D}_j}{|}^2\right|{\mathrm{\β}}_{i,j}{|}^2{N}_{S_i{R}_j}})$

In above formula,

${\mathrm{\β}}_{i,j}=P_{R_j}/\left(P_{S_i}\right|a_{S_i{D}_i}{|}^2+N_{S_i{D}_i})$

Wherein,For representing the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and receiving terminal,Represent the channel coefficients of yardstick decline between i-th primary user's transmitting terminal and i-th trunk subscriber transmitting terminal,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and i-th time user's receiving terminal,Represent the Background Noise Power between trunk subscriber transmitting terminal and primary user's receiving terminal on channel i,Represent the channel coefficients of yardstick decline between i-th trunk subscriber transmitting terminal and jth time user's receiving terminal,Represent the Background Noise Power between primary user's transmitting terminal and trunk subscriber transmitting terminal on channel i,Represent the transmitting power of jth trunk subscriber,Represent the transmitting power of primary user i；

C_{i,j_sec}Computing formula and C_{i_dir}Computing formula principle identical, particularly as follows:

$C_{i,j\_\sec }=w_j{\log }_2(1+{\mathrm{SNR}}_{{\mathrm{jR}}_i{\mathrm{RD}}_i})$

Wherein,

${\mathrm{SNR}}_{{\mathrm{jR}}_i{\mathrm{RD}}_i}=|a_{R_i{\mathrm{RD}}_i}{|}^2{P}_{{\mathrm{RS}}_i}/N_{{\mathrm{jR}}_i{\mathrm{RD}}_i}$

WhereinRepresent that time user is to R_i、RD_iSignal to noise ratio when transmitting on channel j, w_jRepresent the channel width of j-th strip channel,Represent the transmitting power of time user i；Represent the Background Noise Power on channel j；For representing the channel coefficients of yardstick decline, define as follows:

$a_{R_i{\mathrm{RD}}_i}=h_{R_i{\mathrm{RD}}_i}/d_i^{v/2}$

Wherein d_iRepresent the i-th pair time distance between user transmitter and receiver；V represents variable channel fading factor；R_i、RD_iRepresent the secondary user transmitter on i-th channel and receiver respectively；Represent the channel gain between secondary user transmitter and the receiver on i-th channel.