CN102833761A - Method for secondary users assisting master users to relay in multichannel multi-master user cognitive network - Google Patents

Abstract

The invention discloses a method for secondary users assisting master users to relay in a multichannel multi-master user cognitive network. The method includes steps: subjecting time to time division; simultaneously considering rate sum of all master users needing data transmission in a master user time slot to enable the rate sum of the master users to be maximum, establishing an optimized question, and distributing secondary users as relay nodes; in a secondary user time slot, if a certain secondary user wants to transmit data, access can be realized only when contribution value of the secondary user is large enough, simultaneously lowering the contribution value of the secondary user accessed to a channel at current time slot; and in the master user time slot, distributing an algorithm assisting the master users as a distribution algorithm based on the ant colony algorithm according to the optimized question. The master users are assisted by the secondary users serving as the relay nodes, so that improvement of transmission rate is obtained; and in addition, the secondary users are accessed to the secondary time slot reserved by the master users, so that a right to access to spectrum transmission data is obtained, throughput of the whole cognitive network is improved, and practicability and feasibility are high.

Description

Time user assists the method for main user's relaying in the how main user's cognition network of multichannel

Technical field

What the present invention relates to is a kind of method of cognitive radio networks technical field; Especially a kind of with relay application under the multichannel scene; There is the mechanism of many cognitive radio networks to main user in each channel, is specifically related to the method that time user in the how main user's cognition network of multichannel assists main user's relaying.

Background technology

Cognitive radio technology is an application technology that is used to alleviate the rare key of problem of frequency spectrum resource.In order to realize cognitive radio system, a lot of design problems are arranged.A wherein very important problem is exactly to realize main user and time user's coexistence.

In traditional cognitive radio system, inferior user is through frequency spectrum perception technology, and " frequency spectrum cavity-pocket " that exists in the spectrum space around the search promptly do not have yet or frequency range that only part is authorized to CU is used for the transmission of its data.But time user has only searched for not by the frequency spectrum resource of main CU passively in this mechanism, under the prerequisite of interfere with primary users not, inserts this frequency spectrum resource, fails and main user forms sufficient interaction, has wasted the available spectrum resource.

Consider primary and secondary user's interaction from the pecuniary compensation aspect; A kind of main user and time mechanism of user's coexistence of realizing is: when inferior user wants to insert frequency spectrum resource; Main user quantizes inferior user's the interference power that access produced; It is charged, and the power of inferior user's access is high more, needs the Qian Yue that pays many.Main user and time user consider total revenue (comprising the income that the power of access obtains and the income of money) separately respectively, through game theoretic method, realize primary and secondary user's coexistence.But this mechanism has supposed that main user has abundant frequency spectrum resource to be leased to time user, guarantees that simultaneously the communication requirement of oneself can not receive tangible influence.Yet main user often need surpass the High Data Rate of frequency spectrum load.Therefore, in such scene, this mechanism is also improper.

The scene that higher data is arranged to main user; Consider primary and secondary user's interaction from the rate compensation aspect, a kind of in addition main user and time mechanism of user's coexistence of realizing is: on the one hand, and when main user has data to transmit; Inferior user is as relaying; Assist main user transmission, the transmission rate that it has accelerated main user has been transmitted main user to want the data of transmitting quickly; On the other hand, when main user need not be transmitted data, frequency spectrum resource is distributed to the inferior user who has assisted main user's transmission.Generally speaking, improved the utilance of frequency spectrum.

Existingly consider from the rate compensation aspect to be only applicable to multichannel the mechanism of primary and secondary user interaction, there is single scene to main user in each channel.For multichannel, there are many scenes to main user in each channel, does not have suitable mechanism.Simultaneously, how to lease frequency spectrum for main user and give time user, also and have and do not have corresponding method.

Summary of the invention

The present invention is directed to multichannel, there are many scenes to main user in each channel, and a kind of mechanism of considering the primary and secondary user interaction from the rate compensation aspect is provided.

The present invention realizes through following technical scheme.

According to an aspect of the present invention; Provide in the how main user's cognition network of a kind of multichannel time user to assist the method for main user's relaying; Under the multichannel scene, there is the mechanism of many cognitive radio networks to main user in each channel with relay application, and it comprises the steps:

Step (1): with the time time slotization;

Step (2): at main user's time slot: the speed of considering the main user that all need transmit data simultaneously with; Make main user's speed and maximum, and set up optimization problem, according to the allocation algorithm that proposes with this; Distribute each time user as via node, assist main user to transmit data; To the inferior user who has assisted main user to transmit, increase its contribution margin L _k

Step (3): at inferior user's time slot: if certain time user wants to transmit data, and if only if this time user's contribution margin L _kMore than or equal to L _ThThe time, could insert; Upgrade each time user's contribution margin simultaneously: current time slots has inserted the inferior user contribution value L of channel _kTo reduce.

Preferably, in said step (1), adopt the method with the time time slotization, particularly, the time shaft of division does not stop repetition by the time slot cycle; Each slot cycle is made up of H main user's time slot and 1 user's time slot: at each main user's time slot, main user selects directly to transmit or some time user assists its transmission; At each time user's time slot, inferior user can its data of access channel transmission.

Preferably, in said step (2), particularly, the method for setting up optimization problem is:

Definition relay selection variable is:

If the main user j on the channel i adopts directly transmission, then transmission rate is:

$C_{i,j}^{\mathrm{dir}}=w_i[\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_1}})+\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_2}})]$

Wherein

${\mathrm{<figure-callout\; id="1"\; label="P\; I"\; filenames="HDA00002015300500021.png,HDA00002015300500022.png"\; state="\{\{state\}\}">P</figure-callout>}}_{I_{}}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

${\mathrm{<figure-callout\; id="2"\; label="P\; I"\; filenames="HDA00002015300500021.png,HDA00002015300500022.png"\; state="\{\{state\}\}">P</figure-callout>}}_{I_{}}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

If the main user j on the channel i adopts time user k to transmit as relaying, then transmission rate is:

$C_{i,j,k}^{\mathrm{coop}}=w_i\min \{\log (1+{\mathrm{SNR}}_{\mathrm{sr}}{\left|a_{\mathrm{sr}}\right|}^2),\log (1+{\mathrm{SNR}}_{\mathrm{sd}}{\left|a_{\mathrm{sd}}\right|}^2+{\mathrm{SNR}}_{\mathrm{rd}}{\left|a_{\mathrm{rd}}\right|}^2)\}$

$=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}+P_{I_3}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}+P_{I_4}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}+P_{I_5}})\}$

Wherein

${\mathrm{<figure-callout\; id="3"\; label="P\; I"\; filenames="HDA00002015300500021.png"\; state="\{\{state\}\}">P</figure-callout>}}_{I_{}}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{r}_k}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_4}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_5}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

Then the transmission rate of the main user j on the channel i is expressed as:

$U_{i,j}=(1-\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j,k})\&CenterDot;C_{i,j}^{\mathrm{dir}}+\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}(x_{i,j,k}\&CenterDot;C_{i,j,k}^{\mathrm{coop}})$

Total main user rate be expressed as:

$S=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{U}_{i,j}$

The relay selection variable satisfies following restrictive condition:

$\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{x}_{i,j,k}=0\mathrm{or}1,(k=\mathrm{1,2},...,Q)$

Preferably, in said step (3), particularly, all inferior users that want to transmit data that contribution margin is surpassed threshold value are according to contribution margin L _kSort, according to contribution margin height order, each time user selects the best channel of its channel condition is inserted according to its transmission rate at each channel successively.

Preferably, at main user's time slot, distribute time user to assist main user's algorithm to be allocation algorithm based on ant group algorithm according to optimization problem.

Preferably, at main user's time slot, distribute time user to assist main user's algorithm according to optimization problem and be allocation algorithm, specifically comprise the steps: based on ant group algorithm

The first step, the plain τ of initialization information ₀(i, j is k) with heuristic information η _n(k), wherein, the heuristic information formula is for i, j:

${\mathrm{\&eta;}}_n(i,j,k)=\left\{\begin{array}{cc}{C}_{i,j,k}^{\&prime;\mathrm{coop}}& \&ForAll;k\&Element;\{\mathrm{1,2},...,Q\}\\ C_{i,j,k}^{\&prime;\mathrm{dir}}& k=\mathrm{<figure-callout\; id="1"\; label="Q\; +"\; filenames="HDA00002015300500021.png,HDA00002015300500022.png"\; state="\{\{state\}\}">Q</figure-callout>}+1.\end{array}\right.$

Wherein

$C_{i,j,k}^{\&prime;\mathrm{coop}}=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}})$

$C_{i,j,k}^{\&prime;\mathrm{dir}}=w_i{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}});$

Second goes on foot, and constructs the solution space of every ant according to following formula:

$p_{i,j,k}=\frac{{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)}{{\underset{k=1}{\overset{Q+1}{\mathrm{\&Sigma;}}}}_{k\&Element;{\mathrm{\&theta;}}_{i,j}}{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)},$

The 3rd step, calculate the corresponding target function value of every ant, the ant that the select target functional value is maximum remembers that its corresponding target function value is S ^Best, its corresponding choice variable does

In the 4th step, lastest imformation is plain:

τ _n+1(i，j，k)←(1-ρ)τ _n(i，j，k)+Δτ _n

The 5th step repeated said second step, and in the 3rd step, the 4th step is up to reaching maximum iteration time N _MaxChoice variable x according to the optimum of trying to achieve _{I, j, k}Distribute time user to assist main user.

Compared with prior art, the invention has the beneficial effects as follows: be applicable to multichannel, there are many scenes to main user in each channel.Under this scene: (1) main user has obtained the lifting of transmission rate through the assistance of time user as via node; (2) inferior user inserts inferior user's time slot that main user reserves, and has obtained to insert the right of frequency spectrum transmission data; (3) promote the throughput of whole cognition network, so improved the utilance of frequency spectrum.

Description of drawings

The sketch map of the matching algorithm that Fig. 1 is adopted at main user's time slot for the present invention;

Fig. 2 for the present invention at 3 channels, each channel master user is 10,8,6 to number, when inferior user is 20, total main user's transmitted bit number is with the curve chart of arrival rate of bag;

Fig. 3 for the present invention at 3 channels, each channel master user is 10,8,6 to number, when inferior user is 20, total inferior user's transmitted bit number is with the curve chart of arrival rate of bag.

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment being to implement under the prerequisite with technical scheme of the present invention.

Present embodiment is in the experiment scene of a 1000m * 1000m, to carry out.The number of channel is 3, and all channels have identical bandwidth w=1kHz, and each channel master user logarithm is respectively: 8,7,9, and inferior user's number: 20, emission signal to noise ratio 60dB.In the present embodiment, get H=8, the duration of each time slot is T _Slot=1s, the size of each bag is 500bits, each user wrap arrival rate obey parameter be λ (individual/s) independently Poisson process, continue 20 slot cycles altogether.And it is 50 times that maximum iteration time is set, α=1, β=0.8, γ=0.0001, ρ=0.05.The practical implementation method is:

(1) at each main user's time slot: the speed of considering the main user that all need transmit data simultaneously with; Make main user's speed and maximum, and set up optimization problem, according to the allocation algorithm that proposes with this; Distribute each time user as via node, assist main user to transmit data.To the inferior user who has assisted main user to transmit, with its contribution margin L _kAdd 1.

The method of specifically setting up optimization problem is:

Definition relay selection variable is:

If the main user j on the channel i adopts directly transmission, then transmission rate is:

$C_{i,j}^{\mathrm{dir}}=w_i[\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_1}})+\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_2}})]$

Wherein

$P_{I_1}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_2}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

If the main user j on the channel i adopts time user k to transmit as relaying, then transmission rate is:

$C_{i,j,k}^{\mathrm{coop}}=w_i\min \{\log (1+{\mathrm{SNR}}_{\mathrm{sr}}{\left|a_{\mathrm{sr}}\right|}^2),\log (1+{\mathrm{SNR}}_{\mathrm{sd}}{\left|a_{\mathrm{sd}}\right|}^2+{\mathrm{SNR}}_{\mathrm{rd}}{\left|a_{\mathrm{rd}}\right|}^2)\}$

$=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}+P_{I_3}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}+P_{I_4}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}+P_{I_5}})\}$

Wherein

$P_{I_3}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{r}_k}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_4}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_5}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

Then the transmission rate of the main user j on the channel i is expressed as:

$U_{i,j}=(1-\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j,k})\&CenterDot;C_{i,j}^{\mathrm{dir}}+\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}(x_{i,j,k}\&CenterDot;C_{i,j,k}^{\mathrm{coop}})$

Total main user rate be expressed as:

$S=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{U}_{i,j}$

The relay selection variable satisfies following restrictive condition:

$\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{x}_{i,j,k}=0\mathrm{or}1,(k=\mathrm{1,2},...,Q)$

(2) at certain time user's time slot: if certain time user wants to transmit data, and if only if this time user's contribution margin L _kMore than or equal to L _ThWhen (being set to 3 in this emulation), could insert.Concrete access way is: all inferior users that want to transmit data are according to contribution margin L _kSort (the inferior user that the contribution margin that only sorts surpasses threshold value), according to contribution margin height order, each time user selects the best channel of its channel condition is inserted according to its transmission rate at each channel successively.Upgrade each time user's contribution margin simultaneously: current time slots has inserted the inferior user contribution value L of channel _kTo reduce.

At main user's time slot, distributing time use to assist main user's algorithm according to optimization problem is the allocation algorithm based on ant group algorithm, and its step is following:

The first step, the plain τ of initialization information ₀(i, j is k) with heuristic information η _n(i, j, k).Wherein, the heuristic information formula is:

${\mathrm{\&eta;}}_n(i,j,k)=\left\{\begin{array}{cc}{C}_{i,j,k}^{\&prime;\mathrm{coop}}& \&ForAll;k\&Element;\{\mathrm{1,2},...,Q\}\\ C_{i,j,k}^{\&prime;\mathrm{dir}}& k=\mathrm{<figure-callout\; id="1"\; label="Q\; +"\; filenames="HDA00002015300500021.png,HDA00002015300500022.png"\; state="\{\{state\}\}">Q</figure-callout>}+1.\end{array}\right.$

Wherein

$C_{i,j,k}^{\&prime;\mathrm{coop}}=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}})$

$C_{i,j,k}^{\&prime;\mathrm{dir}}=w_i{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}})$

Second goes on foot, and constructs the solution space of every ant according to following formula:

$p_{i,j,k}=\frac{{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)}{{\underset{k=1}{\overset{Q+1}{\mathrm{\&Sigma;}}}}_{k\&Element;{\mathrm{\&theta;}}_{i,j}}{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)}$

The 3rd step, calculate the corresponding target function value of every ant, the ant that the select target functional value is maximum remembers that its corresponding target function value is S ^Best, its corresponding choice variable does

In the 4th step, lastest imformation is plain:

τ _n+1(i，j，k)←(1-ρ)τ _n(i，j，k)+Δτ _n

The 5th step repeated said second step, and in the 3rd step, the 4th step is up to reaching maximum iteration time N _MaxChoice variable x according to the optimum of trying to achieve _{I, j, k}Distribute time user to assist main user.

Fig. 2 has provided the curve chart of the total transmitted bit number of main user with the arrival rate of bag; Fig. 3 has provided the curve chart of the total transmitted bit number of inferior user with the arrival rate of bag.Visible by Fig. 2: use the method that relaying is arranged, the bit number that total all traditional than the use non-relay method of transmitted bit number of main user is transmitted is many.Visible by Fig. 3, use the method that relaying is arranged, the bit number that the total transmitted bit number non-relay method more traditional than use of inferior user transmitted is many.

More than specific embodiment of the present invention is described.It will be appreciated that the present invention is not limited to above-mentioned specific implementations, those skilled in the art can make various distortion or modification within the scope of the claims, and this does not influence flesh and blood of the present invention.

Claims (6)

1. time user assists the method for main user's relaying in the how main user's cognition network of multichannel, it is characterized in that, under the multichannel scene, there is the mechanism of many cognitive radio networks to main user in each channel with relay application, and it comprises the steps:

Step (1): with the time time slotization;

Step (2): at main user's time slot: the speed of considering the main user that all need transmit data simultaneously with; Make main user's speed and maximum, and set up optimization problem, according to the allocation algorithm that proposes with this; Distribute each time user as via node, assist main user to transmit data; To the inferior user who has assisted main user to transmit, increase its contribution margin L _k

Step (3): at inferior user's time slot: if certain time user wants to transmit data, and if only if this time user's contribution margin L _kMore than or equal to L _ThThe time, could insert; Upgrade each time user's contribution margin simultaneously: current time slots has inserted the inferior user contribution value L of channel _kTo reduce.

2. time user assists the method for main user's relaying in the how main user's cognition network of multichannel according to claim 1; It is characterized in that, in said step (1), adopt method the time time slotization; Particularly, the time shaft of division does not stop repetition by the time slot cycle; Each slot cycle is made up of H main user's time slot and 1 user's time slot: at each main user's time slot, main user selects directly to transmit or some time user assists its transmission; At each time user's time slot, inferior user can its data of access channel transmission.

3. time user assists the method for main user's relaying in the how main user's cognition network of multichannel according to claim 1, it is characterized in that in said step (2), particularly, the method for setting up optimization problem is:

Definition relay selection variable is:

If the main user j on the channel i adopts directly transmission, then transmission rate is:

$C_{i,j}^{\mathrm{dir}}=w_i[\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_1}})+\frac{1}{2}{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}+P_{I_2}})]$

Wherein

$P_{I_1}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_2}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

If the main user j on the channel i adopts time user k to transmit as relaying, then transmission rate is:

$C_{i,j,k}^{\mathrm{coop}}=w_i\min \{\log (1+{\mathrm{SNR}}_{\mathrm{sr}}{\left|a_{\mathrm{sr}}\right|}^2),\log (1+{\mathrm{SNR}}_{\mathrm{sd}}{\left|a_{\mathrm{sd}}\right|}^2+{\mathrm{SNR}}_{\mathrm{rd}}{\left|a_{\mathrm{rd}}\right|}^2)\}$

$=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}+P_{I_3}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}+P_{I_4}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}+P_{I_5}})\}$

Wherein

$P_{I_3}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{r}_k}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_4}=\underset{j=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}{\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}$

$P_{I_5}=\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}(1-\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j^{\&prime;},k}){\left|a_{s_{{i,j}^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{s_{{i,j}^{\&prime;}}}+\underset{j^{\&prime;}=1,j^{\&prime;}\&NotEqual;j}{\overset{P_i}{\mathrm{\&Sigma;}}}\underset{k^{\&prime;}=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{{i,j,k}^{\&prime;}}{\left|a_{r_{k^{\&prime;}}{d}_{i,j}}\right|}^2{P}_{r_{k^{\&prime;}}}$

Then the transmission rate of the main user j on the channel i is expressed as:

$U_{i,j}=(1-\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}{x}_{i,j,k})\&CenterDot;C_{i,j}^{\mathrm{dir}}+\underset{k=1}{\overset{Q}{\mathrm{\&Sigma;}}}(x_{i,j,k}\&CenterDot;C_{i,j,k}^{\mathrm{coop}})$

Total main user rate be expressed as:

$S=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{U}_{i,j}$

The relay selection variable satisfies following restrictive condition:

$\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{P_i}{\mathrm{\&Sigma;}}}{x}_{i,j,k}=0\mathrm{or}1,(k=\mathrm{1,2},...,Q)$

4. time user assists the method for main user's relaying in the how main user's cognition network of multichannel according to claim 1; It is characterized in that; In said step (3), particularly, all inferior users that want to transmit data that contribution margin is surpassed threshold value are according to contribution margin L _kSort, according to contribution margin height order, each time user selects the best channel of its channel condition is inserted according to its transmission rate at each channel successively.

5. time user assists the method for main user's relaying in the how main user's cognition network of multichannel according to claim 1; It is characterized in that; At main user's time slot, distribute time user to assist main user's algorithm to be allocation algorithm based on ant group algorithm according to optimization problem.

6. time user assists the method for main user's relaying in the how main user's cognition network of multichannel according to claim 5; It is characterized in that; At main user's time slot, distribute time user to assist main user's algorithm according to optimization problem and be allocation algorithm, specifically comprise the steps: based on ant group algorithm

The first step, the plain τ of initialization information ₀(i, j is k) with heuristic information η _n(k), wherein, the heuristic information formula is for i, j:

${\mathrm{\&eta;}}_n(i,j,k)=\left\{\begin{array}{cc}{C}_{i,j,k}^{\&prime;\mathrm{coop}}& \&ForAll;k\&Element;\{\mathrm{1,2},...,Q\}\\ C_{i,j,k}^{\&prime;\mathrm{dir}}& k=Q+1.\end{array}\right.$

Wherein

$C_{i,j,k}^{\&prime;\mathrm{coop}}=w_i\min \{\log (1+{\left|a_{s_{i,j}{r}_k}\right|}^2\frac{P_{s_{i,j}}}{N_{r_k}}),\log (1+{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2\frac{P_{s_{i,j}}}{N_{d_{i,j}}}+{\left|a_{r_k{d}_{i,j}}\right|}^2\frac{P_{r_k}}{N_{d_{i,j}}})$

$C_{i,j,k}^{\&prime;\mathrm{dir}}=w_i{\log }_2(1+\frac{{\left|a_{s_{i,j}{d}_{i,j}}\right|}^2{P}_{s_{i,j}}}{N_{d_{i,j}}});$

Second goes on foot, and constructs the solution space of every ant according to following formula:

$p_{i,j,k}=\frac{{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)}{{\underset{k=1}{\overset{Q+1}{\mathrm{\&Sigma;}}}}_{k\&Element;{\mathrm{\&theta;}}_{i,j}}{\mathrm{\&tau;}}_n^{\mathrm{\&alpha;}}(i,j,k){\mathrm{\&eta;}}_n^{\mathrm{\&beta;}}(i,j,k)};$

The 3rd step, calculate the corresponding target function value of every ant, the ant that the select target functional value is maximum remembers that its corresponding target function value is S ^Best, its corresponding choice variable does

In the 4th step, lastest imformation is plain:

τ _n+1(i，j，k)←(1-ρ)τ _n(i，j，k)+Δτ _n

The 5th step repeated said second step, and in the 3rd step, the 4th step is up to reaching maximum iteration time N _MaxChoice variable x according to the optimum of trying to achieve _{I, j, k}Distribute time user to assist main user.

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