CN104540208A - Speed and power self-adaptation method based on physical layer network coding - Google Patents

Abstract

The invention discloses a speed and power self-adaptation method based on physical layer network coding and belongs to the technical field of communication networks. The method includes the steps that firstly, network transmission conditions are set, signals are sent, then the relation among the bit error rate, the transmission power and the transmission speed which are obtained after decoding is constructed according to the signals received by a receiving end, a signal transmission first time slot is constructed according to the relation of the bit error rate, the transmission power and the transmission speed, when the signal transmission speed is fixed, the constraint condition of the transmission power is optimized, and finally the signal transmission first time slot, the optimal signal transmission rate, the optimal transmitting power set of a transmitting end and the optimal transmission speed of a signal transmission second time slot are obtained and set to be fixed values in network data transmission. According to the speed and power self-adaptation method, under the condition of reasonable time delay, the network throughput is improved, the transmission time delay is shortened, the signal transmission time is shortened, the effectiveness of the network is ensured, the speed and power self-adaptation method is suitable for various network environments in which a PNC can be adopted, and the speed and power self-adaptation method has large practical value in practical network transmission.

Description

The power rate adaptive approach of physically based deformation layer network coding

Technical field

The invention belongs to technical field of communication network, particularly a kind of power rate adaptive approach of physically based deformation layer network coding.

Background technology

Network code can improve the throughput of wireless network, legacy network coding (conventional network coding, CNC) in, via node receives the packet from source node respectively and encodes, and is then gone out by the data packet broadcast after coding; And physical-layer network coding (physical-layer network coding, PNC) network throughput can be improved greatly on the basis of CNC, when adopting physical-layer network coding, via node is encoded to the packet from source node received simultaneously, and is broadcasted by broadcast channel; One employing amplification forwarding (amplify-and-forward, AF) of PNC and denoising forward (denoise-and-forward, DNF) two kinds of trunking schemes, adopt the PNC of amplification forwarding mode to be also referred to as ANC.

In the wireless network, channel condition along with channel fading profiles and node location change and change, in order to maximization network throughput, adaptively modifying message transmission rate is necessary with adaptive channel condition; Most of existing work mainly concentrates research to support the rate adaptation mechanism of legacy network coding (CNC), and the rate adaptation mechanism of physically based deformation layer network coding (PNC) is not extensively studied; But PNC is respectively on the basis of encoding from source node data bag at CNC, take the strategy that the packet from source node is encoded simultaneously, be compared to CNC, PNC saves transmission time slot number further, thus network throughput can be improved greatly, therefore study the application of PNC in real network and there is very large Research Significance and practical value; Have at present and study based on the rate adaptation of amplification forwarding (AF) PNC, but mainly consider the impact of channel capacity, take the method for fixed rate, power, in actual applications due to impact that channel condition often changes, always accurately can not find optimal solution, network throughput can also be further enhanced, and is also never studied by people based on the power-rate self adaptation of denoising forwarding (DNF) PNC.

Summary of the invention

For the deficiencies in the prior art, the present invention proposes the power rate adaptive approach of a kind of physically based deformation layer network coding, improves network throughput to reach, reduce propagation delay time, ensures network reliability and facilitates the object of practical application.

Technical solution of the present invention is as follows:

The power rate adaptive approach of physically based deformation layer network coding, comprises the following steps:

Step 1, signal in network is set transmits on additive white Gaussian noise channel, the signal that transmitting terminal 1, transmitting terminal 2 and relay router are launched all adopts M-QAM modulation system, receiving terminal 1 and receiving terminal 2 decoded signal are all based on minimum distance criterion, and baseband signal is set as that rolloff-factor is the raised cosine pulse signal of 1;

Step 2, Signal transmissions first time slot, transmitting terminal 1 sends signal to relay router, and transmitting terminal 2 sends signal to relay router, and receiving terminal 1 monitors the signal that transmitting terminal 2 is launched simultaneously, and receiving terminal 2 monitors the signal that transmitting terminal 1 is launched;

Noise in the signal that step 3, the signal sent to the channel coefficients of relay router, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the channel coefficients of relay router, transmitting terminal 2 and wireless network, obtains the relaying superposed signal that relay router receives; The signal that the signal sent to the channel coefficients of receiving terminal 1, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the interchannel noise of receiving terminal 1, transmitting terminal 2 to channel coefficients and the transmitting terminal 2 of receiving terminal 1, obtains the signal that receiving terminal 1 listens to; The signal that the signal sent to the channel coefficients of receiving terminal 2, transmitting terminal 2 according to transmitting terminal 2, transmitting terminal 1 send to the interchannel noise of receiving terminal 2, transmitting terminal 1 to channel coefficients and the transmitting terminal 1 of receiving terminal 2, obtains the signal that receiving terminal 2 listens to;

Step 4, build bit error rate, relation between transmitting power and transmission rate after decoding, concrete steps are as follows:

Step 4.1, bit error rate after setting error sign ratio equals to decode, according to order of modulation, transmitting terminal 1 is to the channel coefficients of relay router, transmitting terminal 2 is to the channel coefficients of relay router, the transmitting power of transmitting terminal 1, the transmitting power of transmitting terminal 2, the extraneous harmful interference power of noise power and relay router, obtain the decoded error sign ratio that relay router receives relaying superposed signal, namely relay router receives bit error rate after the decoding of relaying superposed signal, bit error rate after the decoding of structure relaying superposed signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate,

Step 4.2, according to order of modulation, transmitting terminal 2 to the channel coefficients of receiving terminal 1, transmitting terminal 1 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 1, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 1, obtain receiving terminal 1 and listen to bit error rate after the decoding of signal, build receiving terminal 1 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate;

Step 4.3, according to order of modulation, transmitting terminal 1 to the channel coefficients of receiving terminal 2, transmitting terminal 2 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 2, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 2, obtain receiving terminal 2 and listen to bit error rate after the decoding of signal, build receiving terminal 2 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate;

Step 5, be set in Signal transmissions first time slot, when signal transmission rate is fixed, the constraints of optimal transmission power, specific as follows:

Constraints 1: in the optimal power of transmitting terminal 1 and the optimal power of transmitting terminal 2, have at least one to equal specified maximum transmission power;

Constraints 2: the optimal transmit power obtained at least meets one of them constraint formulations following:

Constraint formulations (1) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}---\left(1\right)$

Wherein, represent the optimal transmit power of transmitting terminal 2, represent the optimal transmit power of transmitting terminal 1, T represents the english abbreviation of transmitting, s ₁represent transmitting terminal 1, s ₂represent transmitting terminal 2;

for transmitting terminal 2 is to the channel coefficients of receiving terminal 1, represent channel situation, M represents order of modulation, σ _nrepresent noise power, represent receiving terminal 1 extraneous harmful interference power summation, d ₁represent that receiving terminal 1, n represents the english abbreviation of noise;

$b_1=\sqrt{\frac{3{\left|h_{s_1,d_1}\right|}^2{(L-1)}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_1})}},$ represent the channel coefficients of transmitting terminal 1 to receiving terminal 1, $L=\sqrt{M};$

represent the channel coefficients of transmitting terminal 1 to receiving terminal 2, represent receiving terminal 2 extraneous harmful interference power summation;

represent the channel coefficients of transmitting terminal 2 to receiving terminal 2, d ₂represent receiving terminal 2;

Constraint formulations (2) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)---\left(2\right)$

Wherein, represent the channel coefficients of transmitting terminal 1 to relay router, I _rrepresent relay router extraneous harmful interference power summation, r represents relay router, f _m() represents the monotonically increasing function of minimum value between the transmitting power of transmitting terminal 1 and the transmitting power of transmitting terminal 2;

Constraint formulations (3) is as follows:

$a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(3\right)$

Wherein, represent the channel coefficients of transmitting terminal 2 to relay router;

Constraint formulations (4) is as follows:

$f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(4\right);$

Step 6, acquisition Signal transmissions first time slot, Optimal Signals transmission rate and transmitting terminal optimal transmit power group, concrete steps are as follows:

Bit error rate threshold value after step 6.1, setting decoding, setting order of modulation initial value is 2;

The transmitting power of step 6.2, setting transmitting terminal 1 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 1 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 2;

The transmitting power of step 6.3, setting transmitting terminal 2 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 2 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 1;

8 optimal transmit power that step 6.4, basis obtain obtain 8 rear bit error rates of decoding, and bit error rate after 8 decodings is compared, transmitting terminal 1 corresponding to selection bit error rate minimum value and the transmitting power of transmitting terminal 2, as the optimal transmit power group of current order of modulation;

Step 6.5, judge the decoding that optimal transmit power group is corresponding after bit error rate whether be less than bit error rate threshold value after the decoding of setting, if so, order of modulation is multiplied by 2, and returns and perform step 6.2, otherwise, perform step 6.6;

Step 6.6, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions first time slot, and using optimal transmit power group corresponding for current order of modulation as Signal transmissions first time slot optimal transmit power group;

Step 7, Signal transmissions second time slot, relaying superposed signal is carried out denoising coding by relay router, and be sent in receiving terminal 1 and receiving terminal 2, according to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 1 and the noise in wireless network, obtain the signal that receiving terminal 1 receives, according to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 2 and the noise in wireless network, obtain the signal that receiving terminal 2 receives;

Step 8, acquisition Signal transmissions second time slot, optimal transmission speed, concrete steps are as follows:

Step 8.1, setting transmitting terminal 1 and the transmitting power of transmitting terminal 2 are specified maximum transmission power, bit error rate threshold value after the decoding of setting receiving terminal, and to arrange order of modulation initial value be 2;

Step 8.2, obtain receiving terminal 1 receive signal decoding after bit error rate and receiving terminal 2 receive bit error rate after signal decoding, and whether bit error rate is all less than the rear bit error rate threshold value of setting decoding after judging the decoding of all acquisitions, if, order of modulation is multiplied by 2, and repeated execution of steps 8.2, otherwise, perform step 8.3;

Step 8.3, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions second time slot:

Step 9, the Signal transmissions first time slot Optimal Signals transmission rate of acquisition and optimal transmit power group are set as the fixed value of Signal transmissions first time slot network data transmission the Signal transmissions second time slot Optimal Signals transmission rate of acquisition is set as the fixed value of Signal transmissions second time slot network data transmission.

Acquisition relay router described in step 4.1 receives the rear bit error rate of relaying superposed signal decoding, adopts following formula:

$p_{b,r}=1-{(1-\frac{2(L-1)}{L}Q\left(f_M\left(\min \right\{c_1\sqrt{P_{T,s_1}},c_2\sqrt{P_{T,s_2}}\left\}\right)\right))}^2---\left(5\right)$

Wherein, p _{b, r}represent that relay router receives bit error rate after the decoding of relaying superposed signal, b represents the english abbreviation of bit error rate, and Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.

Acquisition receiving terminal 1 described in step 4.2 listens to bit error rate after signal decoding, adopts following formula:

$p_{b,d_1}=1-{(1-\frac{2(L-1)}{L}Q\left(\min \right\{{0,a}_1\sqrt{P_{T,s_2}}{-b}_2\sqrt{P_{T,s_1}}\}))}^2---\left(6\right)$

Wherein, represent that receiving terminal 1 receives bit error rate after the decoding of monitoring signal, Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.

Acquisition receiving terminal 2 described in step 4.3 listens to bit error rate after signal decoding, adopts following formula:

$p_{b,d_2}=1-{(1-\frac{2(L-1)}{L}Q\left(\min \right\{{0,a}_2\sqrt{P_{T,s_1}}{-b}_2\sqrt{P_{T,s_2}}\}))}^2---\left(7\right)$

Wherein, represent that receiving terminal 2 receives bit error rate after the decoding of monitoring signal, Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.

Beneficial effect of the present invention:

The present invention is based on the power rate adaptive approach of DNF-PNC when reasonable time delay, network throughput has remarkable lifting, reduce propagation delay time, higher and the network of stable throughput has very large benefit for needs, improve network performance to a greater extent, save signal transmission time, ensure that the validity and reliability of network; This method is applicable to the multiple network environment that can adopt PNC, in real network transmission, have larger using value.

Accompanying drawing explanation

Fig. 1 is based on the PNC structural representation of " X " topological structure with two flows;

Fig. 2 is the wheel-type topological structure schematic diagram of an embodiment of the present invention;

Fig. 3 is the #-type topological structure schematic diagram of an embodiment of the present invention;

Fig. 4 is the power rate adaptive approach flow chart of the physically based deformation layer network coding of an embodiment of the present invention;

Fig. 5 is acquisition Signal transmissions first time slot of an embodiment of the present invention, Optimal Signals transmission rate and transmitting terminal optimal transmit power group flow chart;

Fig. 6 is the graph of a relation that each scheme network throughput changes with interstitial content in wheel topological structure of an embodiment of the present invention;

Fig. 7 is the graph of a relation that each scheme end-to-end time delay changes with interstitial content in wheel topological structure of an embodiment of the present invention;

Fig. 8 is the graph of a relation that each scheme network in #-type topological structure of an embodiment of the present invention is told the amount of gulping down and changed with data package transmission velocity.

Embodiment

Below in conjunction with accompanying drawing to specific embodiment of the invention detailed description in addition.

The embodiment of the present invention is based on the PNC of " X " topological structure with two flows, and as shown in Figure 1, in figure, (1) is Signal transmissions first time slot, and (2) are Signal transmissions second time slot, "-→ " be monitored link, " → " is transmission link, for interfering link, consider single relaying and many relayings two kinds of situations, pair wheel type topological sum #-type topology carries out analog simulation respectively;

Wheel-type topological structure as shown in Figure 2, transmitting terminal s ₁, s ₂..., s _iwith receiving terminal d ₁, d ₂..., d _ibe distributed in in the relay router r circle that is the center of circle, radius is 150m, and transmitting terminal and receiving terminal can intercourse information by common relay router r, and the angle between the limit of two transmitting terminal-receiving terminal compositions is (as s ₁→ d ₁and s ₂→ d ₂between angle) random distribution constantly change between 0 to 2 π.Transmitting terminal is in overstocked state always, and namely they always have signal to send;

#-type topological structure as shown in Figure 3, n ₁to n ₁₆represent 16 computers, the distance arranging each computer and adjacent computers is 175m, and arranges n ₁→ n ₁₅, n ₂→ n ₁₆, n ₇→ n ₃, n ₁₄→ n ₁₀article four, data flow.

In the embodiment of the present invention, all formula utilize MATLAB software to calculate, and with MATLAB software and the assessment of C language associative simulation, 10 groups of different data are set at random, and emulate 10 times, each simulation time is 50s, and the specified maximum transmission power setting all transmitting terminals is 3dBm.

This method is applied to media access control layer (MAC) agreement (OPNC-MAC) of existing support physical-layer network coding and chance monitoring by the embodiment of the present invention, be called supporting rate-power adaptive, the media access control layer agreement (RPOPNC-MAC) that physical-layer network coding and chance are monitored, and with existing transmission means support, there is the media access control layer agreement (CNC-MAC) that reliable broadcast characteristic legacy network encodes, traditional IEEE802.11 agreement (802.11), support the media access control layer agreement (OPNC-MAC) that physical-layer network coding and chance are monitored, the media access control layer agreement (R-CNC-MAC) of supporting rate adaptation function legacy network coding and the 802.11 media access control layer agreements (R-802.11) with rate adaptation function carry out performance evaluation contrast, the advantage of verification method.

The power rate adaptive approach of physically based deformation layer network coding, method flow diagram as shown in Figure 4, comprises the following steps:

Step 1, signal in network is set transmits on additive white Gaussian noise channel, the signal that transmitting terminal 1, transmitting terminal 2 and relay router are launched all adopts M-QAM modulation system, receiving terminal 1 and receiving terminal 2 decoded signal are all based on minimum distance criterion, and baseband signal is set as that rolloff-factor is the raised cosine pulse signal of 1;

Step 2, Signal transmissions first time slot, transmitting terminal 1 sends signal to relay router, and transmitting terminal 2 sends signal to relay router, and receiving terminal 1 monitors the signal that transmitting terminal 2 is launched simultaneously, and receiving terminal 2 monitors the signal that transmitting terminal 1 is launched;

Noise in the signal that step 3, the signal sent to the channel coefficients of relay router, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the channel coefficients of relay router, transmitting terminal 2 and wireless network, obtaining the relaying superposed signal that relay router receives is:

$y_r=h_{s_1,r}{x}_1+h_{s_2,r}{x}_2+z_n---\left(8\right)$

Wherein, y _rrepresent the relaying superposed signal that relay router receives, represent the channel coefficients of transmitting terminal 1 to relay router, represent channel situation, x ₁represent the signal that transmitting terminal 1 sends, represent the channel coefficients of transmitting terminal 2 to relay router, x ₂represent the signal that transmitting terminal 2 sends, z _nrepresent the noise in wireless network, r represents relay router, s ₁represent transmitting terminal 1, s ₂represent that transmitting terminal 2, n represents the english abbreviation of noise;

The signal that the signal sent to the channel coefficients of receiving terminal 1, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the interchannel noise of receiving terminal 1, transmitting terminal 2 to channel coefficients and the transmitting terminal 2 of receiving terminal 1, obtaining the signal that receiving terminal 1 listens to is:

$y_{d_1}=h_{s_2,d_1}{x}_2+(h_{s_1,d_1}{x}_1+z_n)---\left(9\right)$

Wherein, represent the signal that receiving terminal 1 listens to, represent the channel coefficients of transmitting terminal 1 to receiving terminal 1, represent the channel coefficients of transmitting terminal 2 to receiving terminal 1, d ₁represent receiving terminal 1;

The signal that the signal sent to the channel coefficients of receiving terminal 2, transmitting terminal 2 according to transmitting terminal 2, transmitting terminal 1 send to the interchannel noise of receiving terminal 2, transmitting terminal 1 to channel coefficients and the transmitting terminal 1 of receiving terminal 2, obtaining the signal that receiving terminal 2 listens to is:

$y_{d_2}=h_{s_1,d_2}{x}_1+(h_{s_2,d_2}{x}_2+z_n)---\left(10\right)$

Wherein, represent the signal that receiving terminal 2 listens to, represent the channel coefficients of transmitting terminal 1 to receiving terminal 2, represent the channel coefficients of transmitting terminal 2 to receiving terminal 2, d ₂represent receiving terminal 2;

Step 4, build bit error rate, relation between transmitting power and transmission rate after decoding, concrete steps are as follows:

Step 4.1, bit error rate after setting error sign ratio equals to decode, according to order of modulation, transmitting terminal 1 is to the channel coefficients of relay router, transmitting terminal 2 is to the channel coefficients of relay router, the transmitting power of transmitting terminal 1, the transmitting power of transmitting terminal 2, the extraneous harmful interference power of noise power and relay router, obtain the decoded error sign ratio that relay router receives relaying superposed signal, namely relay router receives bit error rate after the decoding of relaying superposed signal, bit error rate after the decoding of structure relaying superposed signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate, adopt following formula:

$p_{b,r}=1-{(1-\frac{2(L-1)}{L}Q\left(f_M\left(\min \right\{c_1\sqrt{P_{T,s_1}},c_2\sqrt{P_{T,s_2}}\left\}\right)\right))}^2---\left(5\right)$

Wherein, p _{b, r}represent that relay router receives bit error rate after the decoding of relaying superposed signal, b represents the english abbreviation of bit error rate, and T represents the english abbreviation of transmitting, and Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2, f _m() represents the monotonically increasing function of minimum value between the transmitting power of transmitting terminal 1 and the transmitting power of transmitting terminal 2;

i _rrepresent relay router extraneous harmful interference power summation, M represents order of modulation, σ _nrepresent noise power;

$c_2=\sqrt{\frac{3{\left|h_{s_2,r}\right|}^2}{(M-1)({\mathrm{\σ}}_n^2+I_r)}};$

In the embodiment of the present invention, arrange $f_M\left(\min \right\{c_1\sqrt{P_{T,s_1}},c_2\sqrt{P_{T,s_2}}\left\}\right)=\min \{c_1\sqrt{P_{T,s_1}},c_2\sqrt{P_{T,s_2}}\};$

Step 4.2, according to order of modulation, transmitting terminal 2 to the channel coefficients of receiving terminal 1, transmitting terminal 1 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 1, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 1, obtain receiving terminal 1 and listen to bit error rate after the decoding of signal, build receiving terminal 1 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate, adopt following formula:

$p_{b,d_1}=1-{(1-\frac{2(L-1)}{L}Q\left(\min \right\{{0,a}_1\sqrt{P_{T,s_2}}{-b}_2\sqrt{P_{T,s_1}}\}))}^2---\left(6\right)$

Wherein, represent that receiving terminal 1 receives bit error rate after the decoding of monitoring signal;

$a_1=\sqrt{\frac{3{\left|h_{s_2,d_1}\right|}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_1})}};b_1=\sqrt{\frac{3{\left|h_{s_1,d_1}\right|}^2{(L-1)}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_1})}};$

Step 4.3, according to order of modulation, transmitting terminal 1 to the channel coefficients of receiving terminal 2, transmitting terminal 2 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 2, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 2, obtain receiving terminal 2 and listen to bit error rate after the decoding of signal, build receiving terminal 2 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate, adopt following formula:

$p_{b,d_2}=1-{(1-\frac{2(L-1)}{L}Q\left(\min \right\{{0,a}_2\sqrt{P_{T,s_1}}{-b}_2\sqrt{P_{T,s_2}}\}))}^2---\left(7\right)$

Wherein, represent that receiving terminal 2 receives bit error rate after the decoding of monitoring signal;

$a_2=\sqrt{\frac{3{\left|h_{s_1,d_2}\right|}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_2})}};b_2=\sqrt{\frac{3{\left|h_{s_2,d_2}\right|}^2{(L-1)}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_2})}};$

Step 5, be set in Signal transmissions first time slot, when signal transmission rate is fixed, the constraints of optimal transmission power, specific as follows:

Constraints 1: in the optimal power of transmitting terminal 1 and the optimal power of transmitting terminal 2, have at least one to equal specified maximum transmission power;

Constraints 2: the optimal transmit power obtained at least meets one of them constraint formulations following:

Constraint formulations (1) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}---\left(1\right)$

Wherein, represent the optimal transmit power of transmitting terminal 2, represent the optimal transmit power of transmitting terminal 1;

Constraint formulations (2) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)---\left(2\right)$

Constraint formulations (3) is as follows:

$a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(3\right)$

Constraint formulations (4) is as follows:

$f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(4\right);$

Step 6, acquisition Signal transmissions first time slot, Optimal Signals transmission rate and transmitting terminal optimal transmit power group, as shown in Figure 5, concrete steps are as follows for method flow diagram:

After step 6.1, setting decoding, bit error rate threshold value is 10 ^-5, setting order of modulation initial value is 2;

The transmitting power of step 6.2, setting transmitting terminal 1 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 1 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 2;

The transmitting power of step 6.3, setting transmitting terminal 2 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 2 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 1;

8 optimal transmit power that step 6.4, basis obtain obtain 8 rear bit error rates of decoding, and bit error rate after 8 decodings is compared, transmitting terminal 1 corresponding to selection bit error rate minimum value and the transmitting power of transmitting terminal 2, as the optimal transmit power group of current order of modulation;

Step 6.5, judge the decoding that optimal transmit power group is corresponding after bit error rate whether be less than bit error rate threshold value after the decoding of setting, if so, order of modulation is multiplied by 2, and returns and perform step 6.2, otherwise, perform step 6.6;

Step 6.6, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions first time slot, and using optimal transmit power group corresponding for current order of modulation as Signal transmissions first time slot optimal transmit power group;

Step 7, Signal transmissions second time slot, relaying superposed signal is carried out denoising coding by relay router, and be sent in receiving terminal 1 and receiving terminal 2, according to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 1 and the noise in wireless network, the signal that acquisition receiving terminal 1 receives is:

$y_{d_1}^{\′}=h_{r,d_1}{C}_{\mathrm{PNC}}\left(y_r\right)+z_n---\left(11\right)$

Wherein, represent the signal that receiving terminal 1 receives, represent the channel coefficients of relay router to receiving terminal 1, C _pNC(y _r) represent denoising coding after relaying superposed signal;

According to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 2 and the noise in wireless network, the signal that acquisition receiving terminal 2 receives is:

$y_{d_2}^{\′}=h_{r,d_2}{C}_{\mathrm{PNC}}\left(y_r\right)+z_n---\left(12\right)$

Wherein, represent the signal that receiving terminal 2 receives, represent the channel coefficients of relay router to receiving terminal 2;

Step 8, acquisition Signal transmissions second time slot, optimal transmission speed, concrete steps are as follows:

The transmitting power of step 8.1, setting transmitting terminal 1 and transmitting terminal 2 is specified maximum transmission power, and after the decoding of setting receiving terminal, bit error rate threshold value is 10 ^-5, and to arrange order of modulation initial value be 2;

Step 8.2, obtain receiving terminal 1 receive signal decoding after bit error rate and receiving terminal 2 receive bit error rate after signal decoding, and whether bit error rate is all less than the rear bit error rate threshold value of setting decoding after judging the decoding of all acquisitions, if, order of modulation is multiplied by 2, and repeated execution of steps 8.2, otherwise, perform step 8.3;

Bit error rate after described Received signal strength decoding, adopts following formula:

$p_s=1-{(1-\frac{2(L-1)}{L}Q\left(\sqrt{\frac{{3E}_s}{(M-1)({\mathrm{\σ}}_n^2+I_{n_j})T_s}}\right))}^2---\left(13\right)$

Wherein, p _sbit error rate after the decoding of expression Received signal strength, E _srepresent the signal receiving strength of each signal, represent receiving terminal n _jextraneous harmful interference power summation, T _srepresent the duration of each signal, s represents signal;

represent transmitting terminal n _ithrough-put power, represent transmitting terminal n _ito receiving terminal n _jchannel coefficients, i and j represents numbering;

Step 8.3, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions second time slot;

Step 9, the Signal transmissions first time slot Optimal Signals transmission rate of acquisition and optimal transmit power group are set as the fixed value of Signal transmissions first time slot network data transmission the Signal transmissions second time slot Optimal Signals transmission rate of acquisition is set as the fixed value of Signal transmissions second time slot network data transmission.

In the embodiment of the present invention, Fig. 6 is the graph of a relation that each scheme network throughput changes with interstitial content in wheel topological structure, "--×--" curve represents the media access control layer agreement (RPOPNC-MAC) that supporting rate-power adaptive, physical-layer network coding and chance are monitored, "--◇--" curve represents the media access control layer agreement (R-CNC-MAC) that supporting rate adaptation function legacy network is encoded curve represents the 802.11 media access control layer agreements (R-802.11) with rate adaptation function, "--zero--" curve represents the media access control layer agreement that holder reason layer network coding and chance are monitored, "----" curve expresses support for the media access control layer agreement (CNC-MAC) with reliable broadcast characteristic legacy network coding, "---*---" curve represents traditional IEEE802.11 agreement (802.11), as can be seen from the figure, compare and do not carry out the agreement of rate adaptation, the throughput of carrying out the agreement of rate adaptation is obviously promoted, RPOPNC-MAC is 2.59 compared to OPNC-MAC average throughput flow gain, can find out when adopting the MAC protocol supporting PNC simultaneously, throughput is close to constant,

In the embodiment of the present invention, Fig. 7 is the graph of a relation that each scheme end-to-end time delay changes with interstitial content in wheel topological structure, as can be seen from the figure, adopts in the agreement of rate adaptation, time delay is significantly declined, and the time delay of RPOPNC-MAC agreement be all relate in agreement minimum;

In the embodiment of the present invention, Fig. 8 is that each scheme network tells the graph of a relation that the amount of gulping down changes with data package transmission velocity in #-type topological structure, as can be seen from the figure, RPOPNC-MAC still has best throughput performance, RPOPNC-MAC is 1.76 compared to the average throughput flow gain of OPNC-MAC, R-CNC-MAC has the poorest throughput in the agreement of all employing rate adaptations, and reason is the increase along with data package transmission velocity, node n ₄and n ₁₃the uneven flow at place cause code machine can minimizing, but the overhead of perceptual coding chance still exists, RPOPNC-MAC due to via node can the transfer of data of coordinates operation of source node, therefore performance can not be affected.

Claims (4)

1. a power rate adaptive approach for physically based deformation layer network coding, is characterized in that: comprise the following steps:

Step 1, signal in network is set transmits on additive white Gaussian noise channel, the signal that transmitting terminal 1, transmitting terminal 2 and relay router are launched all adopts M-QAM modulation system, receiving terminal 1 and receiving terminal 2 decoded signal are all based on minimum distance criterion, and baseband signal is set as that rolloff-factor is the raised cosine pulse signal of 1;

Step 2, Signal transmissions first time slot, transmitting terminal 1 sends signal to relay router, and transmitting terminal 2 sends signal to relay router, and receiving terminal 1 monitors the signal that transmitting terminal 2 is launched simultaneously, and receiving terminal 2 monitors the signal that transmitting terminal 1 is launched;

Noise in the signal that step 3, the signal sent to the channel coefficients of relay router, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the channel coefficients of relay router, transmitting terminal 2 and wireless network, obtains the relaying superposed signal that relay router receives; The signal that the signal sent to the channel coefficients of receiving terminal 1, transmitting terminal 1 according to transmitting terminal 1, transmitting terminal 2 send to the interchannel noise of receiving terminal 1, transmitting terminal 2 to channel coefficients and the transmitting terminal 2 of receiving terminal 1, obtains the signal that receiving terminal 1 listens to; The signal that the signal sent to the channel coefficients of receiving terminal 2, transmitting terminal 2 according to transmitting terminal 2, transmitting terminal 1 send to the interchannel noise of receiving terminal 2, transmitting terminal 1 to channel coefficients and the transmitting terminal 1 of receiving terminal 2, obtains the signal that receiving terminal 2 listens to;

Step 4, build bit error rate, relation between transmitting power and transmission rate after decoding, concrete steps are as follows:

Step 4.1, bit error rate after setting error sign ratio equals to decode, according to order of modulation, transmitting terminal 1 is to the channel coefficients of relay router, transmitting terminal 2 is to the channel coefficients of relay router, the transmitting power of transmitting terminal 1, the transmitting power of transmitting terminal 2, the extraneous harmful interference power of noise power and relay router, obtain the decoded error sign ratio that relay router receives relaying superposed signal, namely relay router receives bit error rate after the decoding of relaying superposed signal, bit error rate after the decoding of structure relaying superposed signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate,

Step 4.2, according to order of modulation, transmitting terminal 2 to the channel coefficients of receiving terminal 1, transmitting terminal 1 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 1, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 1, obtain receiving terminal 1 and listen to bit error rate after the decoding of signal, build receiving terminal 1 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate;

Step 4.3, according to order of modulation, transmitting terminal 1 to the channel coefficients of receiving terminal 2, transmitting terminal 2 to the extraneous harmful interference power of the transmitting power of the transmitting power of the channel coefficients of receiving terminal 2, transmitting terminal 1, transmitting terminal 2, noise power and receiving terminal 2, obtain receiving terminal 2 and listen to bit error rate after the decoding of signal, build receiving terminal 2 and listen to bit error rate after the decoding of signal, the transmitting power of transmitting terminal 1, relation between the transmitting power of transmitting terminal 2 and signal transmission rate;

Step 5, be set in Signal transmissions first time slot, when signal transmission rate is fixed, the constraints of optimal transmission power, specific as follows:

Constraints 1: in the optimal power of transmitting terminal 1 and the optimal power of transmitting terminal 2, have at least one to equal specified maximum transmission power;

Constraints 2: the optimal transmit power obtained at least meets one of them constraint formulations following:

Constraint formulations (1) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}---\left(1\right)$

Wherein, represent the optimal transmit power of transmitting terminal 2, represent the optimal transmit power of transmitting terminal 1, T represents the english abbreviation of transmitting, s ₁represent transmitting terminal 1, s ₂represent transmitting terminal 2;

for transmitting terminal 2 is to the channel coefficients of receiving terminal 1, represent channel situation, M represents order of modulation, σ _nrepresent noise power, represent receiving terminal 1 extraneous harmful interference power summation, d ₁represent that receiving terminal 1, n represents the english abbreviation of noise;

$b_1=\sqrt{\frac{3{\left|h_{s_1,d_1}\right|}^2{(L-1)}^2}{(M-1)({\mathrm{\σ}}_n^2+I_{d_1})}},$ represent the channel coefficients of transmitting terminal 1 to receiving terminal 1, $L=\sqrt{M};$

represent the channel coefficients of transmitting terminal 1 to receiving terminal 2, represent receiving terminal 2 extraneous harmful interference power summation;

represent the channel coefficients of transmitting terminal 2 to receiving terminal 2, d ₂represent receiving terminal 2;

Constraint formulations (2) is as follows:

$a_1\sqrt{P_{T,s_2}^{*}}-b_1\sqrt{P_{T,s_1}^{*}}=f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)---\left(2\right)$

Wherein, represent the channel coefficients of transmitting terminal 1 to relay router, I _rrepresent relay router extraneous harmful interference power summation, r represents relay router, f _m() represents the monotonically increasing function of minimum value between the transmitting power of transmitting terminal 1 and the transmitting power of transmitting terminal 2;

Constraint formulations (3) is as follows:

$a_2\sqrt{P_{T,s_1}^{*}}-b_2\sqrt{P_{T,s_2}^{*}}=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(3\right)$

Wherein, represent the channel coefficients of transmitting terminal 2 to relay router;

Constraint formulations (4) is as follows:

$f_M\left(c_1\sqrt{P_{T,s_1}^{*}}\right)=f_M\left(c_2\sqrt{P_{T,s_2}^{*}}\right)---\left(4\right);$

Step 6, acquisition Signal transmissions first time slot, Optimal Signals transmission rate and transmitting terminal optimal transmit power group, concrete steps are as follows:

Bit error rate threshold value after step 6.1, setting decoding, setting order of modulation initial value is 2;

The transmitting power of step 6.2, setting transmitting terminal 1 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 1 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 2;

The transmitting power of step 6.3, setting transmitting terminal 2 is specified maximum transmission power, is brought into respectively by the maximum transmission power of transmitting terminal 2 in network constraint condition 4 constraint formulations, obtains 4 optimal transmit power of transmitting terminal 1;

8 optimal transmit power that step 6.4, basis obtain obtain 8 rear bit error rates of decoding, and bit error rate after 8 decodings is compared, transmitting terminal 1 corresponding to selection bit error rate minimum value and the transmitting power of transmitting terminal 2, as the optimal transmit power group of current order of modulation;

Step 6.5, judge the decoding that optimal transmit power group is corresponding after bit error rate whether be less than bit error rate threshold value after the decoding of setting, if so, order of modulation is multiplied by 2, and returns and perform step 6.2, otherwise, perform step 6.6;

Step 6.6, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions first time slot, and using optimal transmit power group corresponding for current order of modulation as Signal transmissions first time slot optimal transmit power group;

Step 7, Signal transmissions second time slot, relaying superposed signal is carried out denoising coding by relay router, and be sent in receiving terminal 1 and receiving terminal 2, according to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 1 and the noise in wireless network, obtain the signal that receiving terminal 1 receives, according to the relaying superposed signal after relay router to the channel coefficients, denoising coding of receiving terminal 2 and the noise in wireless network, obtain the signal that receiving terminal 2 receives;

Step 8, acquisition Signal transmissions second time slot, optimal transmission speed, concrete steps are as follows:

Step 8.1, setting transmitting terminal 1 and the transmitting power of transmitting terminal 2 are specified maximum transmission power, bit error rate threshold value after the decoding of setting receiving terminal, and to arrange order of modulation initial value be 2;

Step 8.2, obtain receiving terminal 1 receive signal decoding after bit error rate and receiving terminal 2 receive bit error rate after signal decoding, and whether bit error rate is all less than the rear bit error rate threshold value of setting decoding after judging the decoding of all acquisitions, if, order of modulation is multiplied by 2, and repeated execution of steps 8.2, otherwise, perform step 8.3;

Step 8.3, order of modulation stop upgrading, and according to current order of modulation, obtain the optimal transmission speed of Signal transmissions second time slot;

Step 9, the Signal transmissions first time slot Optimal Signals transmission rate of acquisition and optimal transmit power group are set as the fixed value of Signal transmissions first time slot network data transmission the Signal transmissions second time slot Optimal Signals transmission rate of acquisition is set as the fixed value of Signal transmissions second time slot network data transmission.

2. the power rate adaptive approach of physically based deformation layer network coding according to claim 1, is characterized in that: the acquisition relay router described in step 4.1 receives the rear bit error rate of relaying superposed signal decoding, adopts following formula:

$p_{b,r}=1-{(1-\frac{2(L-1)}{L}Q\left(f_M\left(\min \right\{c_1\sqrt{P_{T,s_1}},c_2\sqrt{P_{T,s_2}}\left\}\right)\right))}^2---\left(5\right)$

Wherein, p _{b, r}represent that relay router receives bit error rate after the decoding of relaying superposed signal, b represents the english abbreviation of bit error rate, and Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.

3. the power rate adaptive approach of physically based deformation layer network according to claim 1 coding, is characterized in that: the acquisition receiving terminal 1 described in step 4.2 listens to bit error rate after signal decoding, adopts following formula:

$p_{b,d_1}=1-{(1-\frac{2(L-1)}{L}Q\left(\max \right\{0,a_1\sqrt{P_{T,s_2}}-b_1\sqrt{P_{T,s_1}}\left\}\right))}^2---\left(6\right)$

Wherein, represent that receiving terminal 1 receives bit error rate after the decoding of monitoring signal, Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.

4. the power rate adaptive approach of physically based deformation layer network according to claim 1 coding, is characterized in that: the acquisition receiving terminal 2 described in step 4.3 listens to bit error rate after signal decoding, adopts following formula:

$p_{b,d_2}=1-{(1-\frac{2(L-1)}{L}Q\left(\max \right\{0,a_2\sqrt{P_{T,s_1}}-b_2\sqrt{P_{T,s_2}}\left\}\right))}^2---\left(7\right)$

Wherein, represent that receiving terminal 2 receives bit error rate after the decoding of monitoring signal, Q () represents the upside distribution function of standardized normal distribution, represent the transmitting power of transmitting terminal 1, represent the transmitting power of transmitting terminal 2.