CN104821839A - Cooperative communication system - Google Patents

Abstract

The invention discloses a cooperative communication system and belongs to the communication technical field. The system includes a source user end used for transmitting signals, relay user ends which communicate with the source user end through channels and are used for receiving the signals transmitted by the source user end, and processing the signals according to a cooperative communication strategy between the relay user ends and forwarding the processed signals, and a target user end which communicates with the relay user ends through channels and is used for receiving the signals from the relay user ends, performing demodulation and decoding processing on the signals to obtain original transmitting signals of the source user end. According to the cooperative communication system of the invention, through the cooperative communication of the source user end, the relay user ends and the target user end, a single antenna can be utilized to transmit and receive signals at each user end, and therefore, limitations of a MIMO communication mode at communication terminals such as handheld communication terminals, aircrafts and vehicles in the aspects such as modification, cost and power consumption can be eliminated.

Description

A kind of cooperation communication system

Technical field

The present invention relates to communication technical field, particularly a kind of cooperation communication system.

Background technology

In air communications in the past, it is main analog voice call technology that wireless communication system mainly adopts based on VHF (Very HighFrequency, very high frequency(VHF)).But along with the development of Commercial Air Service, even if minimize the operation demand that also cannot meet airdrome scene completely to VHF channel spacing at present.For this reason, ICAO (International Civil Aviation Organization, International Civil Aviation Organization) in order to improve operational efficiency and the message capacity of airdrome scene, propose AeroMACS (Aeronautical Mobile AirportCommunications System, aviation moving machine course communication system) technology, it will become the part of air communications infrastructure data link.

In whole airdrome scene AeroMACS signal coverage areas, each mobile client is provided in order to meet, at a high speed and reliably wireless broadband business such as such as aircraft, service vehicle etc., the impact how overcoming the communication NLOS (Non Line of Sight, non-line-of-sight propagation) that the barriers such as scene building, trees cause is the problem of overriding concern.Under NLOS signal intelligence, wireless signal can only be propagated by modes such as reflection, scatterings.The signal that receiving terminal receives is the summation of different path signal, and this will cause multipath signal to decline thus affect the demodulation of Received signal strength.

Prior art MIMO (Multiple-Input and Multiple-Output, multiple-input and multiple-output) is a kind of method solved the problem.Be CN200810088724.0 in Chinese Patent Application No., be entitled as in the patent of " signal detecting method of multi-input multi-output system and device ", adopt multiple antennas or array antenna framework to realize the non-correlation of different antennae Received signal strength by transmitting terminal and receiving terminal, thus effectively improve system noise resisting ability.Be 200610005286.8 in Chinese Patent Application No., be entitled as in the patent of " transferring system of broadband wireless access and method thereof ", utilize the distributed MIMO encoding and decoding transmission system of transit node of helping each other, adopt space-time/space-frequency/empty time-frequency/spatial reuse coding method, make full use of the advantage of space division multiplexing, improve the improvement that the capacity of communication system wireless channel and the availability of frequency spectrum realize communication quality without increase in bandwidth exponentially.

Realizing in process of the present invention, inventor finds that prior art at least exists following problem:

Prior art MIMO is directed to civil aviation field, and particularly airborne end or handheld terminal introducing multiaerial system can run into the restriction adding the aspects such as repacking, safety and power consumption.Meanwhile, in channel estimating, in traditional MIMO, channel estimation method cannot directly apply to cascaded channel situation.

Summary of the invention

In order to solve the problem of prior art, the invention provides a kind of cooperation communication system.Described technical scheme is as follows:

First aspect, a kind of cooperation communication system that the embodiment of the present invention provides comprises:

Source user end, for transmitting;

Trunk subscriber end, is communicated with described source user end by channel, for receiving the signal that described source user end is launched, processes, the signal after forward process according to the cooperative communication strategy between trunk subscriber end to signal;

Targeted customer holds, and is communicated with described trunk subscriber end by channel, for receiving the signal from described trunk subscriber end, carrying out demodulation and processing with decoding, obtain the original transmitted signal of source user end to signal.

In a kind of possible implementation of first aspect, described source user end comprises:

Channel encoding unit, carries out chnnel coding process to signal;

Interleaving treatment unit, is connected with described channel encoding unit, carries out interleaving treatment to the signal after chnnel coding process;

Signal madulation unit, is connected with described interleaving treatment unit, carries out signal madulation to the signal through interleaving treatment.

In a kind of possible implementation of first aspect, described source user end also comprises: transmitter, for launching the signal after modulation.

In a kind of possible implementation of first aspect, described trunk subscriber end comprises:

Distributed space time group coding processing unit, for carrying out the process of Alamouti distributed space time group coding to the signal received;

Signal amplification unit, is connected with described distributed space time group coding processing unit, for amplifying the signal after distributed space time group coding processing unit processes and forward.

In a kind of possible implementation of first aspect, described targeted customer's end comprises:

Signal demodulation unit, for carrying out demodulation to the signal received;

Deinterleave processing unit, is connected with described signal demodulation unit, for the process that deinterleaves to the signal after demodulation;

Soft codec processing unit, is connected with the described processing unit that deinterleaves, and for carrying out soft decoding to the signal after deinterleaving, obtains the signal that source user end is launched.

In a kind of possible implementation of first aspect, in described system, at least comprise two trunk subscriber ends.

Second aspect, a kind of targeted customer's end that the embodiment of the present invention provides comprises:

Receiving element, for receiving the signal phasor forwarded by channel by trunk subscriber end;

Demodulating unit, is connected with described receiving element, carries out demodulation for the signal phasor received described receiving element;

Deinterleave unit, is connected with described demodulating unit, for the process that deinterleaves to the signal after log-likelihood calculations;

Convolutional code decoder unit, is connected with the described unit that deinterleaves, and for carrying out convolutional code decoder to the signal after deinterleaving, obtains original transmitted signal.

In a kind of possible implementation of second aspect, described demodulating unit comprises:

First detecting signal unit, for detecting signal phasor according to the lowest mean square root theory of error, obtains the first detection signal;

Secondary signal detecting unit, is connected with described first detecting signal unit, for holding noise vector to be similar to according to Gauss's approaching method to the targeted customer in the first detection signal, obtains the second detection signal;

Log-likelihood calculations unit, is connected with described demodulating unit, for carrying out log-likelihood calculations to the signal after described demodulating unit demodulation.

In a kind of possible implementation of second aspect, described targeted customer's end also comprises acquiring unit, for adopting source user end and all known direct impulse of targeted customer's end to estimate channel, and fetching portion channel condition information.

The third aspect, a kind of trunk subscriber end that the embodiment of the present invention provides comprises:

Receiving element, receives the signal phasor from source user end;

Coding unit, is connected with described receiving element, and vector carries out distributed space time group coding to the received signal;

Amplifying unit, is connected with described coding unit, for amplifying the signal phasor after the process of distributed space time group coding, obtains the vector that transmits;

Transmitting element, is connected with described amplifying unit, and transmitted described in being forwarded by channel vector.

The beneficial effect that the technical scheme that the embodiment of the present invention provides is brought is:

By the collaboration communication that trunk subscriber end and targeted customer hold, single antenna can be utilized to carry out signal transmitting and receiving at each user side, efficiently solve MIMO communication mode and add the limitation in repacking, cost and power consumption etc. at communication terminal such as hand-held communication terminal, aircraft, automobile etc.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described.Apparently, the accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the cooperation communication system structural representation that the embodiment of the present invention one provides;

Fig. 2 is the cooperation communication system structural representation under the NLOS communication scenes that provides of the embodiment of the present invention one;

Fig. 3 is the cooperation communication system structural representation that the embodiment of the present invention two provides;

Fig. 4 is the collaboration communication configuration diagram that the embodiment of the present invention three provides;

Fig. 5 is the collaboration communication method flow chart that the embodiment of the present invention three provides;

Fig. 6 is the another collaboration communication method flow chart that the embodiment of the present invention three provides;

Fig. 7 is targeted customer's end structure schematic diagram that the embodiment of the present invention four provides;

Fig. 8 is the trunk subscriber end structure schematic diagram that the embodiment of the present invention five provides.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

Embodiment one

Embodiments provide a kind of cooperation communication system, see Fig. 1, this system comprises:

Source user end 11, for transmitting;

Trunk subscriber end 12, is communicated with described source user end by channel, for receiving the signal launched from source user end 11, processes, the signal after forward process according to the cooperative communication strategy between trunk subscriber end to signal;

Targeted customer holds 13, is communicated, receive the signal from trunk subscriber end 12 by channel with described trunk subscriber end, carries out demodulation and processes with decoding, obtain the original transmitted signal of source user end 11 to signal.

Wherein, the quantity of trunk subscriber end 12 can be at least two according to concrete application implementation scene.The embodiment of the present invention illustrates for two trunk subscriber ends, but is not construed as limiting the trunk subscriber terminal number amount in specifically practicing.

In a particular embodiment, this cooperation communication system can be used for the movement/stationary user of airdrome scene, such as, slides aircraft, the information interaction of vehicle and scene attendant etc.For this cooperation communication system, the role of user side can need in above-mentioned three Terminal Type intermediate change according to not communication in the same time, namely user side may carry out serving as source user end when signal is launched at needs, when cooperating other user side forward signals as trunk subscriber end, serve as targeted customer's end when Received signal strength.

Cooperation communication system shown in Fig. 2 is the cooperation communication system under NLOS communication scenes.As shown in Figure 2, source user end is airdrome scene aircraft, and targeted customer's end is management and control control tower, there is building and block between airdrome scene aircraft and management and control control tower.Within the system, the user all existed under LOS (Line of Sight, line-of-sight propagation) communication condition with source user end and airdrome scene aircraft and targeted customer's end and management and control control tower is used to serve as trunk subscriber end.After relaying user side receives the signal launched from source user end, by the cooperative communication strategy between trunk subscriber end, signal is processed, be transmitted to targeted customer's end afterwards, after holding by targeted customer process such as carrying out demodulating and decoding to received signal, obtain the primary signal that source user end is launched, complete once complete communication process.

The cooperation communication system that the embodiment of the present invention provides, by the collaboration communication between trunk subscriber end, single antenna can be utilized to carry out signal transmitting and receiving at each user side, efficiently solve MIMO communication mode and add the limitation in repacking, cost and power consumption etc. at communication terminal such as hand-held communication terminal, aircraft, automobile etc.

Embodiment two

Embodiments provide a kind of cooperation communication system, see Fig. 3, this system comprises:

Source user end 31, after carrying out preliminary treatment to signal, transmits;

Wherein, source user end 31 adopts BICM (Bit InterleavedConvolutional Modulation, Bit Interleaved Coded Modulation) to carry out preliminary treatment to signal to signal before signal is launched, and launches afterwards again;

Particularly, source user end 31 comprises:

Channel encoding unit 311, carries out chnnel coding process to signal;

Wherein, this chnnel coding can utilize convolution code.

Interleaving treatment unit 312, is connected with channel encoding unit 311, carries out interleaving treatment to the signal after chnnel coding process;

Signal madulation unit 313, is connected with interleaving treatment unit 312, carries out signal madulation to the signal through interleaving treatment.

Further, source user end also comprises transmitter, for launching the signal after modulation.

Trunk subscriber end 32, for receiving the signal launched from source user end 31, processes signal according to the cooperative communication strategy between trunk subscriber end, the signal after forward process;

Wherein, after trunk subscriber end 32 Received signal strength, after AlamoutiDSTBC (DistributedSpace-Time Block Codes, distributed space time group coding) process is carried out to signal, through amplifying, then forward;

Particularly, trunk subscriber end 32 comprises:

DSTBC processing unit 321, for carrying out Alamouti DSTBC process to the signal received;

Signal amplification unit 322, is connected with DSTBC processing unit 321, for amplifying the signal after DSTBC processing unit 321 processes and forward.

Targeted customer holds 33, receives the signal from trunk subscriber end 32, carries out demodulating and decoding process to signal, obtains the original transmitted signal of source user end 31.

Particularly, targeted customer holds 33 to comprise:

Signal demodulation unit 331, for carrying out demodulation to the signal received;

Wherein, demodulation is carried out to signal and comprises: input and LLR (Logarithm Likelihood Ratio, log-likelihood ratio) calculate;

Deinterleave processing unit 332, is connected with signal demodulation unit 331, for the process that deinterleaves to the signal after demodulation;

Wherein, because the 312 pairs of signal interleaving process of interleaving treatment unit decline for suppressing channel selectivity, therefore, accordingly, the processing unit 332 pairs of signals that deinterleave deinterleave process;

Soft codec processing unit 333, for carrying out convolutional code decoder to the signal after deinterleaving, obtains the signal that source user end 31 is launched.

In the embodiment of the present invention, the quantity of trunk subscriber end 32 can be at least two according to concrete application implementation scene.The embodiment of the present invention illustrates for two trunk subscriber ends, but is not construed as limiting the trunk subscriber terminal number amount in specifically practicing.

The cooperation communication system embodiment of the present invention provided is applied among the NLOS communication scenes shown in Fig. 2, trunk subscriber end adopts the collaboration communication mode based on Alamouti DSTBC, effectively can reduce the impact because multipath fading in non line-of-sight communication brings.

Embodiment three

Embodiments provide a kind of collaboration communication method, the method is based on collaboration communication framework as shown in Figure 4.In the diagram, each sub-channels of channel I and channel II is with f _iand g _irepresent, the collaboration communication method provided due to the embodiment of the present invention illustrates for NLOS communication environment, therefore, can suppose f _iand g _ibe Rayleigh (Rayleigh) channel, and meet non-selective and IID (independent and identicallydistributed, independent same distribution) attenuation characteristic.For this reason, with CN (0,1), channel statistic is described, wherein CN (μ, σ ²) represent that average, variance are respectively μ and σ ²plural number circle Gaussian Profile.In addition, the noise n of suppose relay user side _riwith the noise n of targeted customer's end _dfor white Gaussian noise there is identical variances sigma ², namely ${\mathrm{\σ}}_{n_{\mathrm{ri}}}^2={\mathrm{\σ}}_{n_d}^2={\mathrm{\σ}}^2.$

See Fig. 5, be a kind of collaboration communication method flow chart that the embodiment of the present invention three provides, comprise:

501: targeted customer's termination receives the signal phasor forwarded by channel by trunk subscriber end;

Particularly, this signal phasor specifically can be expressed as:

Wherein, α ₁, α ₂be respectively source user end and trunk subscriber end to transmit amplification factor, for the additive white Gaussian noise of trunk subscriber end i, s is the signal phasor that source user end utilizes two time slots and sends via channel I, s=[s ₁, s ₂] ^t, C _ifor building the parameter matrix of Alamouti DSTBC; (*) represent this variable should ask conjugation according to Alamouti coding requirement or remain unchanged.

The embodiment of the present invention defines PCSI (Partial Channel State Information, impaction of partial channel state information) with h _irepresent.Can obtain after above formula (1) is simplified:

y＝α ₁α ₂Ph+z (2)

And:

$h={[h_1,h_2]}^t={[f_1{g}_1,f_2^{*}{g}_2]}^t---\left(3\right)$

$P=\left(\begin{array}{cc}{s}_1& -s_2^{*}\\ s_2& s_1^{*}\end{array}\right),C_1=\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right),C_2=\left(\begin{array}{cc}0& -1\\ 1& 0\end{array}\right)---\left(4\right)$

In embodiments of the present invention, participate in Fig. 6, can also comprise before 501:

61: trunk subscriber end Received signal strength vector, DSTBC process is carried out to signal phasor;

62: trunk subscriber end amplifies the signal phasor after DSTBC process, obtains the vector that transmits;

In the embodiment of the present invention 61 and 62, particularly, trunk subscriber end i receives signal phasor r _i=[r _i1, r _i2] ^t:

$\left\{\begin{array}{c}{r}_{i1}={\mathrm{\α}}_1{f}_i{s}_1+n_{r_i}\\ r_{i2}={\mathrm{\α}}_1{f}_i{s}_2+n_{r_i}\end{array}\right.,,i=\mathrm{1,2}.---\left(5\right)$

Wherein, α ₁for source user end transmits amplification factor, for the additive white Gaussian noise of trunk subscriber end i, s ₁and s ₂for the signal phasor s=[s that source user end utilizes two time slots to send via channel I ₁, s ₂] ^t.

Trunk subscriber end i utilizes DSTBC to the signal phasor r received _iencoding operation, then obtains the vector t that transmits _i:

$\begin{array}{c}\left[\begin{array}{cc}{t}_1& t_2\end{array}\right]={\mathrm{\α}}_2[C_1{r}_1+C_2{r_2}^{*}]\\ ={\mathrm{\α}}_2\left[\begin{array}{c}\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right)r_1+\left(\begin{array}{cc}0& -1\\ 1& 0\end{array}\right){r_2}^{*}\end{array}\right]={\mathrm{\α}}_2\left(\begin{array}{cc}{r}_{11}& -r_{22}^{*}\\ r_{12}& {r_{21}}^{*}\end{array}\right)\\ ={\mathrm{\α}}_2\left(\begin{array}{cc}{\mathrm{\α}}_1{f}_1{s}_1+n_{r1}& -{\mathrm{\α}}_1{f}_2^{*}{s}_1^{*}-n_{r2}^{*}\\ {\mathrm{\α}}_1{f}_1{s}_2+n_{r1}& {\mathrm{\α}}_1{f}_2^{*}{s}_1^{*}+n_{r1}^{*}\end{array}\right)\end{array}---\left(6\right)$

After trunk subscriber end coding, then through amplifying, obtaining the vector that transmits, and launching this signal phasor, this signal phasor arrives targeted customer's end through channel II, wherein, and α ₂for trunk subscriber end transmits amplification factor.

502: targeted customer's end utilizes MMSE (Minimum Mean Square Error, lowest mean square root error) to detect signal phasor, obtains the first detection signal;

Wherein, the first detection signal is:

$\left\{\begin{array}{c}{\hat{s}}_1={\mathrm{\α}}_1{\mathrm{\α}}_2(h_1^{*}{y}_1+h_2^{*}{y}_2)/({\mathrm{\α}}_1^2{\mathrm{\α}}_2^2{h}^{H}h+{\mathrm{\σ}}_z^2)\\ {\hat{s}}_2={\mathrm{\α}}_1{\mathrm{\α}}_2(h_1^{*}{y}_2-h_2{y}_1^{*})/({\mathrm{\α}}_1^2{\mathrm{\α}}_2^2{h}^{H}h+{\mathrm{\σ}}_z^2)\end{array}\right.---\left(7\right)$

Wherein, (...) ^hrepresent and transpose conjugate process is carried out to vector in bracket; In addition can be expressed as:

${\mathrm{\σ}}_z^2={2\mathrm{\σ}}^2(1+{\mathrm{\α}}_2^2{\mathrm{\Σ}}_{i=1}^2{\left|g_i\right|}^2)---\left(8\right)$

503: targeted customer's end is in the first detection signal, targeted customer is replaced to hold noise with gaussian variable, the Posterior distrbutionp of noise is held to meet the expectation according to gaussian variable and targeted customer equal, the relation that norm is equal, targeted customer's noise is approximately the function of variance, trunk subscriber terminal number order and channel, obtains the second detection signal;

Particularly, from formula (7) ~ (8), need to obtain h to carry out demodulation to signal _iand g _iinformation, and the embodiment of the present invention provide only acquisition h _ibasis on carry out the method for input.From formula (8) cannot obtain, because g _iunknown.Meanwhile, suppose that channel meets Rayleigh damp condition and g _iwhen meeting plural number circle Gaussian Profile, from formula (1), targeted customer holds the element in noise vector z all to include the product term of two gaussian variables, and therefore z does not meet Gaussian random process.In order to calculate the embodiment of the present invention provides the method for z being carried out to Gauss's convergence, specifically comprises:

Utilize a gaussian variable carry out convergence z _i, and between Two Variables, meet following relation:

$E\left\{{\tilde{z}}_i\right\}=E\left\{z_i\right|\hat{h}\}=0$ With $\mathrm{Var}\left\{{\tilde{z}}_i\right\}=\mathrm{Var}\left\{z_i\right|\hat{h}\}---\left(9\right)$

Wherein, represent and obtain condition under z _iconditional expectation, Var represents variance;

Based on above-mentioned formula, can be replaced by following calculated value:

${\mathrm{\σ}}_{\tilde{z}}^2={\mathrm{T\σ}}^2(1+{\mathrm{\α}}_2^2{\mathrm{\Σ}}_{i=1}^{R}G\left({\hat{h}}_i\right))={\mathrm{T\σ}}^2(1+{\mathrm{\α}}_2^{2}R),G\left({\hat{h}}_i\right)=\frac{\left|\right|{\hat{h}}_i\left|\right|K_1\left(2\right|\left|{\hat{h}}_i\right|\left|\right)}{K_0\left(2\right|\left|{\hat{h}}_i\right|\left|\right)}---\left(10\right)$

Wherein, T be signal from source user end to trunk subscriber end, or trunk subscriber end is to the channel usage number in targeted customer's end process; R is trunk subscriber terminal number order, R=2 in Alamouti DSTBC strategy; || || be Frobenius norm, K0 and K1 is respectively 0 rank and 1 rank two class Bessel (Bayes) function of correction.By above-mentioned approaching method approximate processing and computing formula (7) obtains the second detection signal.

504: LLR calculating is carried out to the second detection signal;

Particularly, for the bit b demodulated ₁lLR calculate correspond to s ₁real part, being directed to QPSK (Quadrature Phase Shift Keyin, Quadrature Phase Shift Keying) modulation system LLR can be expressed as follows:

${\mathrm{LLR}}_1=\log \frac{\exp \{-\frac{{({\hat{s}}_{1R}-\mathrm{\β}\sqrt{2}/2)}^2}{{\mathrm{\σ}}_{\mathrm{\ζ}}^2}\}}{\exp \{-\frac{{({\hat{s}}_{1R}+\mathrm{\β}\sqrt{2}/2)}^2}{{\mathrm{\σ}}_{\mathrm{\ζ}}^2}\}}=\frac{2\sqrt{2}\mathrm{\β}{\hat{s}}_{1R}}{{\mathrm{\σ}}_{\mathrm{\ζ}}^2}---\left(11\right)$

Wherein, for real part, and:

$\mathrm{\β}=\frac{{\mathrm{\α}}_1^2{\left|\right|h\left|\right|}^2}{{\mathrm{\α}}_1^2{\left|\right|h\left|\right|}^2+{\mathrm{\σ}}_z^2},{\mathrm{\σ}}_{\mathrm{\ζ}}^2=\frac{{\mathrm{\α}}_1^2{\left|\right|h\left|\right|}^2}{{({\mathrm{\α}}_1^2{\left|\right|h\left|\right|}^2+{\mathrm{\σ}}_z^2)}^2}---\left(12\right)$

505: the signal after LLR calculates is deinterleaved and convolutional code decoder, obtains original transmitted signal.

Wherein, this original transmitted signal is the signal phasor that source user end is launched.

In the embodiment of the present invention, need first to obtain channel condition information h when carrying out demodulation to received signal.For Alamouti DSTBC collaboration communication scheme, the embodiment of the present invention adopts source user end and all known direct impulse of targeted customer's end to estimate channel, and under supposing the direct impulse condition being 2 at Np number, LS (Least Square, least square method) is utilized to obtain channel estimating as follows:

${\hat{h}}_{\mathrm{LS}}^p=\frac{1}{{\mathrm{\α}}_1{N}_p}{\left(P_0^H{P}_0\right)}^{-1}{\mathrm{\Σ}}_{k=1}^{N_p}{P}_0^H{y}_0\left(k\right)---\left(13\right)$

Wherein P ₀define similar with P in formula (4), just correspond to the pulse vector s of detection 2 × 1 ₀; N _pfor the DSTBC block encoding number based on direct impulse in every frame signal.

It should be noted that, LS can replace with and utilize LMMSE (Linear Minimum MeanSquare Error, linear lowest mean square root error) herein, ML (Maximum Likelihood, maximum likelihood) obtains channel estimating

The collaboration communication method that the embodiment of the present invention provides, estimates partial channel knowledge at targeted customer's end by the direct impulse of being launched by source user end, can carry out the detection of Received signal strength according to partial channel knowledge.Compared to complete channel estimation, the method that the embodiment of the present invention provides effectively reduces trunk subscriber end complexity in channel estimation, and effectively improves the overall operation efficiency of communication system.

Embodiment four

The embodiment of the present invention provides a kind of targeted customer to hold, and see Fig. 7, comprising:

Receiving element 71, for receiving the signal phasor forwarded by channel by trunk subscriber end;

Particularly, this signal phasor is as described in embodiment 3 501, and the embodiment of the present invention repeats no more herein.

Demodulating unit 72, for being similar to described signal phasor according to MMSE, obtains the first detection signal; In the first detection signal, targeted customer is replaced to hold noise with gaussian variable, the Posterior distrbutionp of noise is held to meet the expectation according to gaussian variable and targeted customer equal, the relation that norm is equal, targeted customer's noise is approximately the function of variance, trunk subscriber terminal number order and channel, obtains the second detection signal; Log-likelihood calculations is carried out to the second detection signal;

Particularly, this demodulating unit 72 comprises:

First detecting signal unit 721, for detecting signal phasor according to MMSE, obtains the first detection signal;

Secondary signal detecting unit 722, for in the first detection signal, targeted customer is replaced to hold noise with gaussian variable, the Posterior distrbutionp of noise is held to meet the expectation according to gaussian variable and targeted customer equal, the relation that norm is equal, targeted customer's noise is approximately the function of variance, trunk subscriber terminal number order and channel, obtains the second detection signal;

Wherein, the first detection signal, the second detection signal and concrete detection method describe in detail in the embodiment of the present invention three, and the embodiment of the present invention repeats no more herein.

LLR computing unit 723, for carrying out LLR calculating to the second detection signal;

Deinterleave unit 73, for the process that deinterleaves to the signal after LLR calculating;

Convolutional code decoder unit 74, for carrying out convolutional code decoder to the signal after deinterleaving, obtains original transmitted signal.

Wherein, this original transmitted signal is the signal phasor that source user end is launched.

Targeted customer's end that the embodiment of the present invention provides, based on a kind of collaboration communication method that the embodiment of the present invention three provides, estimates partial channel knowledge by the direct impulse of being launched by source user end, can carry out the detection of Received signal strength according to partial channel knowledge.Compared to complete channel estimation, the target terminal user that the embodiment of the present invention provides effectively reduces trunk subscriber end complexity in channel estimation, and effectively improves the overall operation efficiency of communication system.

Embodiment five

The embodiment of the present invention provides a kind of trunk subscriber end, see Fig. 8, comprising:

Receiving element 81, receives the signal phasor from source user end;

Wherein, the signal phasor r received _i=[r _i1, r _i2] ^t:

$\left\{\begin{array}{c}{r}_{i1}={\mathrm{\α}}_1{f}_i{s}_1+n_{r_i}\\ r_{i2}={\mathrm{\α}}_1{f}_i{s}_2+n_{r_i}\end{array}\right.,,i=\mathrm{1,2}.---\left(5\right)$

Wherein, α ₁for source user end transmits amplification factor, for the additive white Gaussian noise of trunk subscriber end i, s ₁and s ₂for the signal phasor s=[s that source user end utilizes two time slots to send via channel I ₁, s ₂] ^t.

Coding unit 82, is connected with receiving element 81, and vector carries out distributed space time group coding to the received signal;

Amplifying unit 83, is connected with coding unit 82, for amplifying the signal phasor after the process of distributed space time group coding, obtains the vector that transmits;

Particularly, coding unit 82 utilizes DSTBC to the signal phasor r received _iencoding operation, then obtains the vector t that transmits _i:

$\begin{array}{c}\left[\begin{array}{cc}{t}_1& t_2\end{array}\right]={\mathrm{\α}}_2[C_1{r}_1+C_2{r_2}^{*}]\\ ={\mathrm{\α}}_2\left[\begin{array}{c}\left(\begin{array}{cc}1& 0\\ 0& 1\end{array}\right)r_1+\left(\begin{array}{cc}0& -1\\ 1& 0\end{array}\right){r_2}^{*}\end{array}\right]={\mathrm{\α}}_2\left(\begin{array}{cc}{r}_{11}& -r_{22}^{*}\\ r_{12}& {r_{21}}^{*}\end{array}\right)\\ ={\mathrm{\α}}_2\left(\begin{array}{cc}{\mathrm{\α}}_1{f}_1{s}_1+n_{r1}& -{\mathrm{\α}}_1{f}_2^{*}{s}_1^{*}-n_{r2}^{*}\\ {\mathrm{\α}}_1{f}_1{s}_2+n_{r1}& {\mathrm{\α}}_1{f}_2^{*}{s}_1^{*}+n_{r1}^{*}\end{array}\right)\end{array}---\left(6\right)$

Transmitting element 83, is connected with coding unit 82, and transmitted described in being forwarded by channel vector.

Wherein, coding unit 82 obtains the vector that transmits after encoding, and sends this signal phasor by transmitting element 83, and this signal phasor arrives targeted customer's end through channel II, wherein, and α ₂for trunk subscriber end transmits amplification factor.

The trunk subscriber end that the embodiment of the present invention provides, based on the collaboration communication method that the embodiment of the present invention three provides, by adopting the collaboration communication method of Alamouti DSTBC, effectively reduces in non line-of-sight communication due to impact that multipath fading brings.

Finally it should be noted that, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

One of ordinary skill in the art will appreciate that all or part of step realizing above-described embodiment can have been come by hardware, the hardware that also can carry out instruction relevant by program completes, described program can be stored in a kind of computer-readable recording medium, the above-mentioned storage medium mentioned can be read-only memory, disk or CD etc.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. a cooperation communication system, is characterized in that, described system comprises:

Source user end, for transmitting;

Trunk subscriber end, is communicated with described source user end by channel, for receiving the signal that described source user end is launched, processes, the signal after forward process according to the cooperative communication strategy between trunk subscriber end to signal;

Targeted customer holds, and is communicated with described trunk subscriber end by channel, for receiving the signal from described trunk subscriber end, carrying out demodulation and processing with decoding, obtain the original transmitted signal of source user end to signal.

2. cooperation communication system according to claim 1, is characterized in that, described source user end comprises:

Channel encoding unit, carries out chnnel coding process to signal;

Interleaving treatment unit, is connected with described channel encoding unit, carries out interleaving treatment to the signal after chnnel coding process;

Signal madulation unit, is connected with described interleaving treatment unit, carries out signal madulation to the signal through interleaving treatment.

3. cooperation communication system according to claim 2, is characterized in that, described source user end also comprises: transmitter, for launching the signal after modulation.

4. cooperation communication system according to claim 1, is characterized in that, described trunk subscriber end comprises:

Distributed space time group coding processing unit, for carrying out the process of Alamouti distributed space time group coding to the signal received;

Signal amplification unit, is connected with described distributed space time group coding processing unit, for amplifying the signal after distributed space time group coding processing unit processes and forward.

5. cooperation communication system according to claim 1, is characterized in that, described targeted customer's end comprises:

Signal demodulation unit, for carrying out demodulation to the signal received;

Deinterleave processing unit, is connected with described signal demodulation unit, for the process that deinterleaves to the signal after demodulation;

Soft codec processing unit, is connected with the described processing unit that deinterleaves, and for carrying out soft decoding to the information after deinterleaving, obtains the signal that source user end is launched.

6. the cooperation communication system according to claim 1-5, is characterized in that, at least comprises two trunk subscriber ends in described system.

7. targeted customer's end, is characterized in that, comprising:

Receiving element, for receiving the signal phasor forwarded by channel by trunk subscriber end;

Demodulating unit, is connected with described receiving element, carries out demodulation for the signal phasor received described receiving element;

Deinterleave unit, is connected with described demodulating unit, for the process that deinterleaves to the signal after log-likelihood calculations;

Convolutional code decoder unit, is connected with the described unit that deinterleaves, and for carrying out convolutional code decoder to the signal after deinterleaving, obtains original transmitted signal.

8. targeted customer's end according to claim 7, it is characterized in that, described demodulating unit comprises:

First detecting signal unit, for detecting signal phasor according to the lowest mean square root theory of error, obtains the first detection signal;

Secondary signal detecting unit, is connected with described first detecting signal unit, for holding noise vector to detect according to Gauss's approaching method to the targeted customer in the first detection signal, obtains the second detection signal;

Log-likelihood calculations unit, is connected with described demodulating unit, for carrying out log-likelihood calculations to the signal after described demodulating unit demodulation.

9. the targeted customer's end according to claim 7-8 any one, it is characterized in that, described targeted customer's end also comprises acquiring unit, for adopting source user end and all known direct impulse of targeted customer's end to estimate channel, and fetching portion channel condition information.

10. a trunk subscriber end, is characterized in that, comprising:

Receiving element, receives the signal phasor from source user end;

Coding unit, is connected with described receiving element, and vector carries out distributed space time group coding to the received signal;

Amplifying unit, is connected with described coding unit, for amplifying the signal phasor after the process of distributed space time group coding, obtains the vector that transmits;

Transmitting element, is connected with described amplifying unit, and transmitted described in being forwarded by channel vector.