CN105577247A - Serial time domain overlap cooperation communication method - Google Patents

Abstract

The invention belongs to the wireless communication technology field and discloses a serial time domain overlap cooperation communication method. The communication method comprises steps of establishing a basic model of serial space-time overlap cooperation communication, arranging a transmission node, a relay node and an object node in a basic model, performing serial time domain overlapping coding on a symbol sequence by a transmission node to form a coding symbol sequence and then transmitting the coding symbol sequence, receiving a coding symbol sequence transmitted by the transmission node by the relay node, performing amplification processing on the coding symbol sequence to form an amplified coding symbol sequence, transmitting the amplified coding symbol sequence, receiving a coding symbol sequence transmitted by the transmission node and the amplified coding symbol sequence transmitted by the relay point by the object node, performing combination processing on the coding symbol sequence and the amplified coding signal sequence to form a combined symbol sequence and transmitting the coding after the combination symbol sequence is formed. The invention adopts the relatively low order modulation to obtain the frequency spectrum efficiency higher than the prior art and can achieve the lower error rate under a low signal to noise ratio condition.

Description

Overlapping collaboration communication method when a kind of serial is empty

Technical field

The invention belongs to wireless communication technology field, overlapping collaboration communication method when particularly a kind of serial is empty.

Background technology

Wireless communication technology is information technology with fastest developing speed, most widely used in recent years.Along with popularizing of smart mobile phone, the supporting role of radio communication to social development seems particularly important.Wide application makes people have higher requirement to wireless communication system, namely higher message transmission rate and the transmission quality of safety and reliability.Improve the important indicator that spectrum efficiency is communication system validity.The major technique of current raising spectrum efficiency of communication system has:

1. multiple-input and multiple-output (MultipleInputandMultipleOutput, MIMO) technology.It is one of key technology in wireless communication system, refer to and many antennas are all set at wireless link two ends, send respectively and Received signal strength simultaneously, make full use of space resources, without the need to increasing frequency spectrum resource and transmitting power, just can obtain spatial multiplex gains and diversity gain, thus improve the spectrum efficiency of system, improve systematic function.But MIMO itself is very high to the requirement of surrounding environment, in some actual scenes, due to restrictions such as own vol, implementation complexity and power consumptions, MIMO technology can not give full play to its advantage.

2. collaboration communication (CooperativeCommunication) technology.It is a kind of new spatial domain diversity technique that the people such as Sendonaris propose, and also claims cooperative diversity technique.Its basic thought is that mobile terminal finds one or more cooperative partner (Partner) in a communications system, each user can help association partner to transmit its information as the via node of cooperative partner while oneself information of transmission, namely the mobile terminal of single antenna passes through shared channel resources in the multi-user case, thus form virtual mimo system to obtain diversity gain, improve the validity and reliability of wireless communication system transmission.Although collaboration communication has the many merits of MIMO technology, and along with the increase of cooperative node number, frequency efficiency also can be promoted accordingly, but the not growth linearly with the increase of cooperative node number of the performance of cooperation communication system, but more and more milder, be tending towards certain certain value the most at last.Along with the increase of cooperative node number, the complexity of whole system also can correspondingly increase.Therefore, cooperative node number should not be arranged too much, and the lifting of system spectral efficiency is subject to certain restrictions.

3. high order modulation and multiplex technique.High order modulation technique and multiplex technique are often used to the spectrum efficiency improving communication system.Such as quadrature amplitude modulation (M-QAM) technology and orthogonal frequency division multiplexi (OFDM).QAM modulation exponent number is higher, and number of constellation points is more, and the rate of information throughput is larger, and spectrum efficiency will be larger; OFDM technology adopts the orthogonal sub-carriers of minimum interval to realize signal multiplexing, and its spectrum efficiency at least doubles than traditional FDM technology in theory.But along with the increase of QAM technology order of modulation, error rate of system can rise, thus cause the reliability of system to reduce, therefore its feasibility of method that increase order of modulation improves spectrum efficiency is little; And OFDM technology is for adapting to wireless channel transmission, needs to add the expense such as Cyclic Prefix, guard band, reduces the ability improving spectrum efficiency.

4. overlapped time division multiplexing (OverlappedTimeDivisionMultiplexing, OVTDM) technology.Overlapping Symbol is regarded as a kind of coding bound relation of self-assembling formation by overlapped time division multiplexing, and the more serious coding gain of overlap is higher.Realize spectral efficient by having a mind to structure Overlapping Symbol, with same frequency spectrum efficiency without the error rate compared with intersymbol interference multidimensional simplex signal, there is obvious decline.

Summary of the invention

The object of this invention is to provide a kind of serial empty time overlapping collaboration communication method, this communication means make use of space diversity advantage and superimposed coding advantage simultaneously, not only adopt low-order-modulated just can obtain spectral efficient, and under the condition that spectrum efficiency is identical, the present invention has the lower error rate than simple high order modulation technique and simple cooperative communication technology in low signal-to-noise ratio situation.

For reaching above object, the present invention is achieved by the following technical solutions.

Overlapping collaboration communication method when a kind of serial is empty, is characterized in that, comprise the following steps:

Step one, sets up the basic model of the overlapping collaboration communication of serial space-time, is provided with sending node, via node and destination node in described basic model;

Step 2, symbol sebolic addressing carries out sending after serial time domain superimposed coding forms coded identification sequence by described sending node;

Step 3, the coded identification sequence that described via node receives the transmission of described sending node carries out sending after amplification process forms amplification coded identification sequence;

Step 4, described destination node receives the coded identification sequence of described sending node transmission and the amplification coded identification sequence of described via node transmission, and decoding output again after coded identification sequence and amplification coded identification sequence being carried out merging treatment formation merging symbol sebolic addressing.

The feature of technique scheme and improvement further:

(1) further, in step 2,

2a), random bipolarity two hex notation sequence carries out being formed without relative shift coded identification sequence, if overlap coefficient is K without the overlapped time division multiplexing coding of relative shift by described sending node ₁;

2b), described sending node by through being added without relative shift coded identification sequence of encode without the overlapped time division multiplexing of relative shift, then the overlapped time division multiplexing carrying out being shifted formation of encoding is shifted coded identification sequence, and overlap coefficient is K ₂;

2c), the displacement coded identification sequence of the overlapped time division multiplexing coding through displacement is sent to described via node and destination node by described sending node respectively.

(2) further, in step 3,

3a), described via node receives the displacement coded identification sequence that described sending node sends, and carries out to it amplifications and formed and amplify the coded identification sequence of being shifted, and magnificationfactorβ is:

$\mathrm{\β}=\frac{\sqrt{P_R}}{\sqrt{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}},$

In formula, h _sRfor sending node is to the fading coefficients of via node channel;

for sending node is to the noise variance of via node channel;

P _sand P _rrepresent the transmitting power of sending node and via node respectively;

3b), amplification displacement coded identification sequence is sent to described destination node by described via node.

(3) further, in step 4,

4a), described destination node receives the displacement coded identification sequence of described sending node transmission and the amplification displacement coded identification sequence of described via node transmission;

4b), in described destination node maximum-ratio combing mode is adopted the displacement coded identification sequence received and amplification displacement coded identification sequence to be merged,

Sending node is to the merge coefficient a of destination node channel _sDfor

$a_{SD}=\frac{\sqrt{P_S}{h}_{SD}^{*}}{{\mathrm{\σ}}_{SD}^2},$

Via node is to the merge coefficient a of destination node channel _rDfor

$a_{RD}=\frac{\sqrt{\frac{P_R}{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{\frac{P_R{\left|h_{RD}\right|}^2+{\mathrm{\σ}}_{SR}^2}{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}+{\mathrm{\σ}}_{RD}^2}=\frac{\mathrm{\β}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{{\mathrm{\β}}^2{\left|h_{RD}\right|}^2\·{\mathrm{\σ}}_{SR}^2+{\mathrm{\σ}}_{RD}^2},$

In formula, h _sR, h _sD, h _rDbe respectively sending node to the fading coefficients of via node channel, sending node to the fading coefficients of destination node channel, via node to the fading coefficients of destination node channel;

H _sR ^*, h _sD ^*, h _rD ^*be respectively h _sR, h _sD, h _rDconjugate;

be respectively sending node to the noise variance of via node channel, sending node to the noise variance of destination node channel, via node to the noise variance of destination node channel;

Merging symbol sebolic addressing after adopting maximum-ratio combing mode to merge is

${\mathrm{\γ}}_{opt}^{AF}=\sqrt{P_S}(a_{SD}\·h_{SD}+\mathrm{\β}\·a_{RD}\·h_{SR}\·h_{RD}),$

4c), export after merging symbol sebolic addressing is adopted the decoding of Viterbi algorithm realization by described destination node.

The invention has the beneficial effects as follows:

(1) realize overlapping collaboration communication pattern in space-time hybrid domain, adopt low-order-modulated just can obtain the spectrum efficiency higher than existing high order modulation technique.

(2) under the condition identical with prior art spectrum efficiency, the error rate that the present invention makes system reach lower in low signal-to-noise ratio situation, namely system has higher performance gain compared with prior art.

Accompanying drawing explanation

The schematic diagram of the basic model set up in overlapping collaboration communication method when Fig. 1 is serial of the present invention sky;

Fig. 2, Fig. 3 be simulation result of the present invention and and the performance comparison figure of high order modulation cooperation communication system under same spectrum efficiency;

In figure: S, sending node; R, via node; D, destination node.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

With reference to Fig. 1, the basic model schematic diagram set up in overlapping collaboration communication method when being serial of the present invention sky; Overlapping collaboration communication method when serial of the present invention is empty, comprises the following steps:

Step one, sets up the basic model of the overlapping collaboration communication of serial space-time, is provided with sending node S, via node R and destination node D in basic model.

Step 2, symbol sebolic addressing carries out sending after serial time domain superimposed coding forms coded identification sequence by sending node S.

The concrete steps of step 2 are as follows:

2a), random bipolarity two hex notation sequence carries out encoding (Pure-OverlappedTimeDivisionMultiplexing without the overlapped time division multiplexing of relative shift by sending node S, P-OVTDM) formed without relative shift coded identification sequence, if overlap coefficient is K ₁.

2b), sending node S is by through being added without relative shift coded identification sequence of encoding without the overlapped time division multiplexing of relative shift, carry out the overlapped time division multiplexing coding (Shift-OverlappedTimeDivisionMultiplexing be shifted again, S-OVTDM) form displacement coded identification sequence, overlap coefficient is K ₂.

2c), the displacement coded identification sequence of the overlapped time division multiplexing coding through displacement is sent to described via node R and destination node D by sending node S respectively.

Step 3, the coded identification sequence that via node R receives sending node S transmission carries out sending after amplification process forms amplification coded identification sequence.

The concrete steps of step 3 are as follows:

3a), via node R receives the displacement coded identification sequence that sending node S sends, and carries out to it amplifications and formed and amplify the coded identification sequence of being shifted, and magnificationfactorβ is:

$\mathrm{\β}=\frac{\sqrt{P_R}}{\sqrt{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}},$

In formula, h _sRfor sending node S is to the fading coefficients of via node R channel, this method emulates under additive white Gaussian noise (AdditiveWhiteGaussianNoise, AWGN) channel circumstance;

for sending node S is to the noise variance of via node R channel;

P _sand P _rrepresent the transmitting power of sending node S and via node R respectively.

3b), amplification displacement coded identification sequence is sent to destination node D by via node R.

Step 4, the coded identification sequence of destination node D reception sending node S transmission and the amplification coded identification sequence of via node R transmission, and decoding output again after coded identification sequence and amplification coded identification sequence being carried out merging treatment formation merging symbol sebolic addressing.

The concrete steps of step 4 are as follows:

4a), destination node D receives the displacement coded identification sequence of sending node S transmission and the amplification displacement coded identification sequence of via node R transmission.

4b), at destination node D maximum-ratio combing (MRC) mode is adopted the displacement coded identification sequence received and amplification displacement coded identification sequence to be merged,

The merge coefficient a of sending node S to destination node D channel _sDfor

$a_{SD}=\frac{\sqrt{P_S}{h}_{SD}^{*}}{{\mathrm{\σ}}_{SD}^2},$

The merge coefficient a of via node R to destination node D channel _rdfor

$a_{RD}=\frac{\sqrt{\frac{P_R}{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{\frac{P_R{\left|h_{RD}\right|}^2+{\mathrm{\σ}}_{SR}^2}{P_S{\left|h_{SR}\right|}^2+{\mathrm{\σ}}_{SR}^2}+{\mathrm{\σ}}_{RD}^2}=\frac{\mathrm{\β}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{{\mathrm{\β}}^2{\left|h_{RD}\right|}^2\·{\mathrm{\σ}}_{SR}^2+{\mathrm{\σ}}_{RD}^2},$

In formula, h _sR, h _sD, h _rDbe respectively fading coefficients, the fading coefficients of sending node S to destination node D channel, the fading coefficients of via node R to destination node D channel of sending node S to via node R channel, this method emulates under awgn channel environment;

H _sR ^*, h _sD ^*, h _rD ^*be respectively h _sR, h _sD, h _rDconjugation;

be respectively noise variance, the noise variance of sending node S to destination node D channel, the noise variance of via node R to destination node D channel of sending node S to via node R channel;

Merging symbol sebolic addressing after adopting maximum-ratio combing mode to merge is

${\mathrm{\γ}}_{opt}^{AF}=\sqrt{P_S}(a_{SD}\·h_{SD}+\mathrm{\β}\·a_{RD}\·h_{SR}\·h_{RD}).$

4c), export after merging symbol sebolic addressing being adopted the decoding of Viterbi algorithm realization.

Effect of the present invention can be further illustrated by following simulation result.

Under same spectrum efficiency, the performance of the high order modulation cooperation communication system thirdly mentioned in the performance of said method and background technology is done simulation comparison analysis; With reference to Fig. 2, Fig. 3, be simulation result of the present invention and and the performance comparison figure of high order modulation cooperation communication system under same spectrum efficiency.

Emulated data is as follows:

Emulate under awgn channel environment, adopt square wave as simulation waveform, the noise n of three interchannels _sD, n _sRand n _rDobeying average is respectively 0, and noise variance is with multiple Gaussian Profile, the signal to noise ratio (E of sending node S to destination node D channel _b/ N ₀) _sDwith the signal to noise ratio (E of via node R to destination node D channel _b/ N ₀) _rDvalue is 14dB, the signal to noise ratio (E of sending node S to via node R channel _b/ N ₀) _sRvalue is 10dB, and power division mode adopts average power allocation, two groups of simulation parameters: (1) input frame number is 8, and every frame bit number is 120000, and spectrum efficiency is η=12bps/Hz, overlap coefficient K ₁, K ₂combination be respectively 1 and 6,2 and 3,3 and 2, corresponding high order modulation is 4096QAM; (2) inputting frame number is 10, and every frame bit number is 120000, and spectrum efficiency is η=8bps/Hz, overlap coefficient K ₁, K ₂combination be respectively 1 and 4,2 and 2, corresponding high order modulation is 256QAM.

(1) first group of emulation, incoming frame is 8 frames, every frame bit number 120000,960000bit altogether, is to different K within the scope of 0 ~ 14dB in signal to noise ratio ₁, K ₂the overlapping coordination model of serial of combination carries out performance simulation, as shown in Figure 2, wherein:

In Fig. 2,4 curves are in identical spectrum efficiency, the bit error rate performance curve namely during η=12bps/Hz.Significantly, the performance of the overlapping cooperative system of serial space-time is better than high order modulation cooperative system, K ₁=1, K ₂=6 and K ₁=2, K ₂the curve of=3 from the off performance is just better than 4096QAM, K ₁=3, K ₂when the curve of=2 is initial, performance is not as 4096QAM, at E _b/ N ₀for performance during about 7dB starts to be better than 4096QAM, and at E _b/ N ₀for 14dB, the bit error rate performance higher-order modulation cooperative system of the overlapping cooperative system of serial space-time is maximum promotes about 5 orders of magnitude; For the overlapping cooperative system of serial space-time, different K ₁, K ₂combination has different bit error rate performances, as can be seen from Figure 3, and K ₁less K ₂larger combination, its bit error rate performance is better.

(2) second groups of emulation, incoming frame is 10 frames, every frame bit number 120000,1200000bit altogether, is to different K within the scope of 0 ~ 14dB in signal to noise ratio ₁, K ₂the overlapping coordination model of serial of combination carries out performance simulation, as shown in Figure 3, wherein:

In Fig. 3,3 curves are in identical spectrum efficiency, the bit error rate performance curve namely during η=8bps/Hz.Simulation result shows, the performance of the overlapping cooperative system of serial space-time is better than high order modulation cooperative system, K ₁=1, K ₂the curve of=4 from the off performance is just better than 256QAM, K ₁=2, K ₂the origin of curve of=2 is identical with 256QAM, and along with the increase of Eb/N0, its performance starts to be better than 256QAM, and at E _b/ N ₀for 12dB, the bit error rate performance higher-order modulation cooperative system of the overlapping cooperative system of serial space-time is maximum promotes about 4 orders of magnitude; Similarly, as can be seen from Figure 3, K ₁less K ₂larger combination, its bit error rate performance is better.The cooperation of the overlap of serial simultaneously is also better than the overlapping cooperation mode of non-serial.

Can draw from above emulation, the present invention not only can realize the raising of spectrum efficiency, and compared with other high order modulation technique under identical state of signal-to-noise, the present invention has more excellent bit error rate performance, and namely the present invention can realize high bit-error performance under Low SNR.

The invention has the beneficial effects as follows:

(1) realize overlapping collaboration communication pattern in space-time hybrid domain, adopt low-order-modulated just can obtain the spectrum efficiency higher than prior art.

(2) under the condition identical with prior art spectrum efficiency, the error rate that the present invention makes system reach lower in low signal-to-noise ratio situation, namely system has higher performance gain compared with prior art.

Although be below described embodiment of the present invention by reference to the accompanying drawings, the present invention is not limited to above-mentioned specific embodiments and applications field, and above-mentioned specific embodiments is only schematic, guiding, instead of restrictive.Those of ordinary skill in the art is under the enlightenment of specification, and when not departing from the scope that the claims in the present invention are protected, can also make a variety of forms, these all belong to the row of the present invention's protection.

Claims (4)

1. overlapping collaboration communication method when serial is empty, is characterized in that, comprise the following steps:

Step one, sets up the basic model of the overlapping collaboration communication of serial space-time, is provided with sending node (S), via node (R) and destination node (D) in described basic model;

Step 2, symbol sebolic addressing carries out sending after serial time domain superimposed coding forms coded identification sequence by described sending node (S);

Step 3, described via node (R) receive coded identification sequence that described sending node (S) sends carry out amplification process formed amplify coded identification sequence after send;

Step 4, described destination node (D) receives coded identification sequence that described sending node (S) sends and the amplification coded identification sequence that described via node (R) sends, and by coded identification sequence and amplify coded identification sequence carry out merging treatment formed merge symbol sebolic addressing after again decoding export.

2. when a kind of serial as claimed in claim 1 is empty, overlapping collaboration communication method, is characterized in that, in step 2,

2a), random bipolarity two hex notation sequence carries out being formed without relative shift coded identification sequence, if overlap coefficient is K without the overlapped time division multiplexing coding of relative shift by described sending node (S) ₁;

2b), described sending node (S) by through being added without relative shift coded identification sequence of encode without the overlapped time division multiplexing of relative shift, then the overlapped time division multiplexing carrying out being shifted formation of encoding is shifted coded identification sequence, and overlap coefficient is K ₂;

2c), the displacement coded identification sequence of the overlapped time division multiplexing coding through displacement is sent to described via node (R) and destination node (D) by described sending node (S) respectively.

3. when a kind of serial as claimed in claim 1 is empty, overlapping collaboration communication method, is characterized in that, in step 3,

3a), described via node (R) receives the displacement coded identification sequence that described sending node (S) sends, and carries out amplification to it and formed and amplify displacement coded identification sequence, and magnificationfactorβ is:

$\mathrm{\β}=\frac{\sqrt{P_R}}{\sqrt{P_S|h_{SR}{|}^2+{\mathrm{\σ}}_{SR}^2}},$

In formula, h _sRfor sending node (S) is to the fading coefficients of via node (R) channel;

for sending node (S) is to the noise variance of via node (R) channel;

P _sand P _rrepresent the transmitting power of sending node (S) and via node (R) respectively;

3b), amplification displacement coded identification sequence is sent to described destination node (D) by described via node (R).

4. when a kind of serial as claimed in claim 3 is empty, overlapping collaboration communication method, is characterized in that, in step 4,

4a), described destination node (D) receives displacement coded identification sequence that described sending node (S) sends and the amplification displacement coded identification sequence that described via node (R) sends;

4b), in described destination node (D) maximum-ratio combing mode is adopted the displacement coded identification sequence received and amplification displacement coded identification sequence to be merged,

Sending node (S) is to the merge coefficient a of destination node (D) channel _sDfor

$a_{SD}=\frac{\sqrt{P_S}{h}_{SD}^{*}}{{\mathrm{\σ}}_{SD}^2},$

Via node (R) is to the merge coefficient a of destination node (D) channel _rDfor

$a_{RD}=\frac{\sqrt{\frac{P_R}{P_S|h_{SR}{|}^2+{\mathrm{\σ}}_{SR}^2}}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{\frac{P_R|h_{RD}{|}^2\·{\mathrm{\σ}}_{SR}^2}{P_S|h_{SR}{|}^2+{\mathrm{\σ}}_{SR}^2}+{\mathrm{\σ}}_{RD}^2}=\frac{\mathrm{\β}\sqrt{P_S}{h}_{SR}^{*}{h}_{RD}^{*}}{{\mathrm{\β}}^2|h_{RD}{|}^2\·{\mathrm{\σ}}_{SR}^2+{\mathrm{\σ}}_{RD}^2},$

In formula, h _sR, h _sD, h _rDbe respectively sending node (S) to the fading coefficients of via node (R) channel, sending node (S) to the fading coefficients of destination node (D) channel, via node (R) to the fading coefficients of destination node (D) channel;

H _sR ^*, h _sD ^*, h _rD ^*be respectively h _sR, h _sD, h _rDconjugate;

be respectively sending node (S) to the noise variance of via node (R) channel, sending node (S) to the noise variance of destination node (D) channel, via node (R) to the noise variance of destination node (D) channel;

Merging symbol sebolic addressing after adopting maximum-ratio combing mode to merge is

${\mathrm{\γ}}_{opt}^{AF}=\sqrt{P_S}(a_{SD}\·h_{SD}+\mathrm{\β}\·a_{RD}\·h_{SR}\·h_{RD});$

4c), export after merging symbol sebolic addressing is adopted the decoding of Viterbi algorithm realization by described destination node (D).