CN101237304A - Asynchronous collaboration air time transmission system and method in broadband wireless sensor network - Google Patents

Abstract

The invention discloses a space-time transmission system used for asynchronous amplify-and-forward cooperative communication of broadband wireless sensor network relay nodes and a method. A timing error estimation module of an information sink node is firstly used to estimate a relative timing error between relay links, an estimation value is fed back to a relay node by a feedback module, power distribution coefficient of each node is determined, further the information sink node processes (such as coding and so on) the character data to be transmitted through modules such as coding modules and so on according to the power distribution coefficient and transmits the character data at a fist time slot; relay ends receive signals sent by the information sink node, then process (such as linear transformation and so on) the received signals through modules such as linear processing modules and so on, according to the power distribution coefficient and transmit the signals at a second time slot; the information sink node receives the signals at the second time slot, removes cyclic prefixes of the received signals and merges the signals, then received symbol data is obtained via an FFT module, a decoding module and an information sink module, so the asynchronous cooperative diversity gain with two as the order under a frequency-selective fading channel can be realized.

Description

The air time transmission system and the method that are used for the broadband wireless sensing network asynchronous cooperation

Technical field

The present invention relates to the wireless messages transmission field, particularly a kind of air time transmission system and method that is used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node.

Background technology

Transmission technology is meant the technology that all adopts many antennas at transmitting terminal and receiving terminal when empty, and it can significantly improve the quality of capability of communication system and wireless transmission link, thereby it has become a research focus in the wireless communication field.Yet owing to be subjected to terminal equipment price, and the influence of factors such as volume, the many antennas of configuration not too gear to actual circumstances on the node of wireless sensor network.In order to address this problem, these two notions of collaboration communication and virtual multi-antenna are arisen at the historic moment.

The collaboration communication technology is a kind of method with distributed form developing space diversity.Utilize the wireless signal characteristics that energy is received by via node on every side in the process of transmission, can communicate information to receiving terminal with cooperating as the transmitting terminal of information source node, thereby reach the purpose of space diversity as the transmitting terminal of via node as information destination node.So, can make the shared antenna each other of each a single aerial system form virtual multi-antenna by certain agreement and come cooperation transmission information, thereby can improve systematic function effectively.And according to the transmitting terminal mode of operation to received signal as via node, the cooperation scheme can be divided into amplifying transmits, deciphers forwarding etc., wherein amplify the forwarding scheme because its complexity is lower, and only need via node to transmit the signal of handling through linearity simply and do not need to decode, therefore be subjected to people more and pay close attention to.

Because these via nodes work in the free space with distributed form, the shortage of the time block that the overall situation is unified and different spatial transmissions are introduced time delay apart from meeting between different via nodes, and promptly these via nodes will work in asynchronous mode.The intersymbol interference that how to resist the timing error introducing is a very important research topic.Although some prior art schemes are considered this situation, some distributed air time transmission system and methods based on asynchronous cooperation have been proposed, these prior art schemes have only been considered the cooperation scheme that decoding is transmitted.And the via node that the cooperation scheme that decoding is transmitted needs cooperation is at random deciphered cooperation transmission again knowing under the code book situation of information source node, and the radio link quality between information source node and via node is had relatively high expectations.In addition, in order to satisfy the requirement of system to broadband connections, the cooperation scheme must overcome the frequency selective fading influence that multipath channel is brought.Consider the low complex degree of amplification forward collaboration scheme, characteristics such as communication system is broadband, transmission problem has become the problem that those skilled in the art need to be resolved hurrily when how to solve under the frequency selective fading channels based on the distributed space in the wireless sensor network of the asynchronous amplification forward collaboration communication of via node.

Summary of the invention

The object of the present invention is to provide a kind of air time transmission system and method that is used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node, overcome the interference of the timing error that exists between the repeated link of different via node correspondences, with space diversity gain under the distributed form developing frequency-selective channel to systematic function.

According to an aspect of of the present present invention, a kind of air time transmission system that is used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node comprises:

Information source module A: be used for information source node and produce the character data that to transmit;

Coding module B is used for information source node to modulating later encoding symbols;

IFFT module C is used for information source node the data after encoding is carried out the IFFT modulation;

Add cyclic prefix module D: be used for every frame data that information source node will obtain and add Cyclic Prefix;

Digital-to-analogue conversion (D/A) module E: be used for information source node digital signal conversion is become analog signal;

Channel module F1～F2: the wireless multipath fading channel between information source node and 2 via nodes;

Analog-to-digital conversion (A/D) module G1～G2: be used for each via node the analog signal that receives is transformed into digital signal;

Remove cyclic prefix module H1～H2: be used for each via node Cyclic Prefix is removed;

Signal processing module I1～I2: each via node is done the corresponding linear processing to receiving data, is used for distributed Space Time Coding;

Add cyclic prefix module J1～J2: be used for each via node the data after handling are added new Cyclic Prefix;

D/A module K1～K2: be used for each via node digital signal conversion is become analog signal;

Wireless multipath fading channel between channel module L1～L2:2 via node and information destination node;

A/D module M: be used for information destination node the analog signal that receives is transformed into digital signal;

Timing error estimation module N: be used for information destination node and estimate relative timing error between the repeated link of concrete different via node correspondences;

Feedback module O: be used for information destination node with feedback information such as timing errors to information source node;

Remove cyclic prefix module P: Cyclic Prefix is removed;

FFT module Q: be used for information destination node the blocks of data that receives is carried out the FFT computing;

Decoding module R: be used for information destination node each subcarrier data is carried out maximum-likelihood decoding;

Stay of two nights module S: output judgement symbol.

According to another aspect of the present invention, a kind of transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty comprises step:

1) information destination node estimates link by the timing error estimation module: information source node → via node 1 → information destination node and link: the relative timing error between information source node → via node 2 → information destination node;

2) feedback module of information destination node is with the relative timing Error Feedback that obtains in the step 1) cyclic prefix module that adds to each via node;

3) information source node is provided with the power partition coefficient that requires to determine information source node and via node according to system;

4) information source node is encoded to the character data that will transmit by coding module;

5) information source node is added Cyclic Prefix by adding cyclic prefix module to the data after encoding, and multiply by power partition coefficient after the IFFT modulation, and launches in first time slot;

6) receive data as the receiving terminal of via node in first time slot, remove and do corresponding linear behind its Cyclic Prefix and handle and be used for distributed Space Time Coding, add new Cyclic Prefix, launch in second time slot then according to power amplification coefficient power amplification ratio;

7) receive data as the receiving terminal of information destination node in second time slot, to after receiving data and removing Cyclic Prefix, transmission course when finishing whole distributed space after FFT module, decoding module and the stay of two nights module.

Wherein, in step 1), the timing error estimation module adopts the auxiliary method of training sequence to estimate link: information source node → via node 1 → information destination node and link: the relative timing error τ between information source node → via node 2 → information destination node.Estimated relative timing error τ is taken as the integral multiple of character data length.

In step 3), information source node is provided with the power partition coefficient p that requires to determine information source node and via node according to feedack according to system ₁And p ₂

In step 4), coding module is encoded to source data in the mode of piece.Length is that the data block of N can be expressed as behind continuous two codings:

x ₁=[x _0,1x _1,1X _N-1,1] ^TAnd x ₂=[x _0,2x _N-1,2X _1,2] ^T, x wherein _{I, j}Be j ∈ 1, the i ∈ of 2} data block 0,1 ..., N-1} character data, () ^T, () ^*() ^HRepresent vector or transpose of a matrix, conjugation, conjugate transpose computing respectively successively.

In step 5), the 2nd data block x ₂After the IFFT modulation, further be treated to P (F ^*x ₂) ^*, P represents contrary cycle shift operation, F is a normalization FFT matrix.

In step 6), add circulating prefix-length and be not shorter than relative timing error τ and maximum multipath tap number sum.{ 1, continuous two block signals that 2} via node receives can be expressed as i ∈ ${\mathrm{<figure-callout\; id="1"\; label="y\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">y</figure-callout>}}_i=H_{\mathrm{SRi}}{F}^{*}{x}_1\sqrt{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+{\mathrm{<figure-callout\; id="1"\; label="n\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">n</figure-callout>}}_i$ With ${\mathrm{<figure-callout\; id="2"\; label="y\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">y</figure-callout>}}_i=H_{\mathrm{SRi}}P{\left(F^{*}{x}_2\right)}^{*}\sqrt{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+n_{i2},$ H wherein _SRiFor information source node and i ∈ 1, the channel matrix between 2} via node, n _I1And n _I2Be i ∈ 1, the white noise of unit power in 2} continuous two data block of via node.For carrying out distributed Space Time Coding, the 1st via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{y}_{11}$ With $-\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{y}_{12},$ The 2nd via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}P{y}_{22}^{*}$ With

$\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}P{y}_{21}^{*}.$

In step 7), the time that the FFT computing begins is as the criterion with the repeating signal that early arrives.

Because have the Space-Time Block Coding structure as each subcarrier data after the receiving terminal FFT processing to received signal of information destination node, the decoding module of receiving terminal can be carried out maximum-likelihood decoding with the fastest speed.Therefore, distributed air time transmission system of the present invention and method can overcome the influence to systematic function of the timing error that exists between the repeated link of different via node correspondences effectively, realized that with lower computation complexity and distributed form exponent number under the frequency selective fading channels is two space diversity gain.

Description of drawings

Fig. 1 is transmission method operating process schematic diagram when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty of the present invention.

Fig. 2 is the air time transmission system transport stream signal journey schematic diagram that is used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node of the present invention.

Fig. 3 is the air time transmission system structural representation that is used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node of the present invention.

Fig. 4 is the FFT arithmetic operation schematic diagram that is used for the air time transmission system of the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node of the present invention.

Fig. 5 is the bit error rate performance schematic diagram that is used for the air time transmission system of the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node of the present invention.

Embodiment

See also Fig. 1 and Fig. 3, of the present invention when being used for the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node empty transmission method mainly may further comprise the steps:

The first step: information destination node estimates link by the auxiliary timing error estimation module of training sequence: information source node → via node 1 → information destination node and link: the relative timing error τ between information source node → via node 2 → information destination node.Estimated relative timing error τ is taken as the integral multiple of character data length.

Second step: the feedback module of information destination node is with the relative timing Error Feedback that obtains in the step 1 cyclic prefix module that adds to via node.

The 3rd step: information source node is provided with the power partition coefficient p that requires to determine information source node and via node according to system ₁And p ₂

The 4th step: information source node is encoded to the character data that will transmit by coding module.Coding module is encoded to source data in the mode of piece.Length is that the data block of N can be expressed as: x behind continuous two codings ₁=[x _0,1x _1,1X _N-1,1] ^TAnd x ₂=[x _0,2x _N-1,2X _1,2] ^T, x wherein _{I, j}Be j ∈ 1, the i ∈ of 2} data block 0,1 ..., N-1} character data, () ^T, () ^*() ^HRepresent vector or transpose of a matrix, conjugation, conjugate transpose computing respectively successively.

The 5th step: information source node is added Cyclic Prefix by adding cyclic prefix module to the data after encoding, and multiply by power partition coefficient after the IFFT modulation, and launches in first time slot.The 2nd data block x ₂After the IFFT modulation, further be treated to P (F ^*x ₂) ^*, P represents contrary cycle shift operation, F is a normalization FFT matrix.Fig. 2 has provided this distributed air time transmission system transport stream signal journey schematic diagram.

The 6th step: receive data as the receiving terminal of via node in first time slot, remove and do corresponding linear behind its Cyclic Prefix and handle and be used for distributed Space Time Coding, add new Cyclic Prefix, launch in second time slot then according to power amplification coefficient power amplification ratio.Add circulating prefix-length and be not shorter than relative timing error τ and maximum multipath tap number sum.{ 1, continuous two block signals that 2} via node receives can be expressed as i ∈ ${\mathrm{<figure-callout\; id="1"\; label="y\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">y</figure-callout>}}_i=H_{\mathrm{SRi}}{F}^{*}{x}_1\sqrt{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+{\mathrm{<figure-callout\; id="1"\; label="n\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">n</figure-callout>}}_i$ With ${\mathrm{<figure-callout\; id="2"\; label="y\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">y</figure-callout>}}_i=H_{\mathrm{SRi}}P{\left(F^{*}{x}_2\right)}^{*}\sqrt{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}+{\mathrm{<figure-callout\; id="2"\; label="n\; i"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">n</figure-callout>}}_i,$ H wherein _SRiFor information source node and i ∈ 1, the channel matrix between 2} via node, n _I1And n _I2Be i ∈ 1, the white noise of unit power in 2} continuous two data block of via node.For carrying out distributed Space Time Coding, the 1st via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{y}_{11}$ With $-\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{y}_{12},$ The 2nd via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}P{y}_{22}^{*}$ With $\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}P{y}_{21}^{*}.$

The 7th step: receive data as the receiving terminal of information destination node in second time slot, to after receiving data and removing Cyclic Prefix, transmission course when finishing whole distributed space after FFT module, decoding module and the stay of two nights module.Wherein, the time that the FFT computing in the signal processing module begins is as the criterion with the repeating signal that early arrives, as shown in Figure 4.The time domain reception data that continuous two time slots are removed behind the Cyclic Prefix are ${\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">z</figure-callout>}}_1=\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{H}_{R1D}{y}_{11}+\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{R}_{\mathrm{\&tau;}}{H}_{R2D}P{y}_{22}^{*}+{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_1$ With ${\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">z</figure-callout>}}_2=-\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{H}_{R1D}{y}_{12}+\sqrt{\frac{p_2}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{R}_{\mathrm{\&tau;}}{H}_{R2D}P{y}_{21}^{*}+{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_2,$ H wherein _RiDBe i ∈ 1, the channel matrix between 2} via node and information destination node, w ₁And w ₂Be the white noise of unit power in continuous two data blocks, R _τExpression cyclic shift τ computing.After the FFT computing, the reception data are $\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">z</figure-callout>}}_1}=\sqrt{\frac{p_2{p}_1}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{\mathrm{\&Lambda;}}_1{x}_1+\sqrt{\frac{p_2{p}_1}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{\mathrm{\&Lambda;}}_2{\mathrm{\&Lambda;}}_{\mathrm{\&tau;}}{x}_2+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">n</figure-callout>}}_1}$ With $\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">z</figure-callout>}}_2}=-\sqrt{\frac{p_2{p}_1}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{\mathrm{\&Lambda;}}_1{x}_2^{*}+\sqrt{\frac{p_2{p}_1}{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">p</figure-callout>}}_1+1}}{\mathrm{\&Lambda;}}_2{\mathrm{\&Lambda;}}_{\mathrm{\&tau;}}{x}_1^{*}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">n</figure-callout>}}_2},$ Wherein $\stackrel{\&OverBar;}{z_i}={\mathrm{Fz}}_i,$ Λ ₁＝Λ _R1dΛ _SR1， ${\mathrm{\&Lambda;}}_2={\mathrm{\&Lambda;}}_{R2D}{\mathrm{\&Lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="SR"\; filenames="S2008100599474E00041.png"\; state="\{\{state\}\}">SR</figure-callout>}2}^{*},$ Λ _SRi=FH _SRiF ^H, Λ _RiD=FH _RiDF ^H, Λ _τFor $\mathrm{diag}\left({\left[F\right]}_{0;N-1,\mathrm{\&tau;}}\sqrt{N}\right),$

With

Be equivalent noise.Because

With

Have the Space-Time Block Coding structure, it is carried out maximum-likelihood decoding, have exponent number and be 2 space diversity gain performance.

Below will further specify the air time transmission system of the asynchronous amplification forward collaboration communication of broadband wireless sensor network trunk node and the systematic function of method of being used for of the present invention by emulation.The system parameters of emulation is set as:

1 information source node of ■, 2 via nodes, 1 information destination node

Channel adopts quasistatic 11 footpaths unit symbol length at interval, the channel model of amplitude exponential damping between each node of ■

Time delay error is 0 to 5 even distribution random value between the repeated link of 2 via node correspondences of ■

It is 64 that the length N of each symbol data piece of ■ is made as

The ■ circulating prefix-length is made as 16

The ■ via node is operated in the amplification forwarding state

The ■ information destination node adopts maximum likelihood decoder

The ■ Frame adopts quarternary phase-shift keying (QPSK) modulation, not coding

■ is by relational expression p ₁=2p ₂Each node power distribution coefficient is set

See also Fig. 5, it has provided the bit error rate performance of distributed air time transmission system of the present invention and method.Give the bit error rate performance of Space-Time Block Coding transmission system among the figure.As can be seen from the figure, at 2p ₁In the bigger zone bit error rate performance curve of this system is basically parallel to the bit error rate performance curve of Space-Time Block Coding transmission system, has illustrated that it is two space diversity gain that this system has obtained exponent number.Simultaneously, each via node does not need to do to received signal decoding, FFT and IFFT operation in this system.Therefore, distributed air time transmission system of the present invention and method can overcome the influence to systematic function of the timing error that exists between the repeated link of different via node correspondences effectively, realized that with lower computation complexity and distributed form exponent number under the frequency selective fading channels is two space diversity gain.

Claims (10)

1. one kind is used for the air time transmission system that the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node is communicated by letter, and comprising:

Information source module A: be used for information source node and produce the character data that to transmit;

Coding module B is used for information source node to modulating later encoding symbols;

IFFT module C is used for information source node the data after encoding is carried out the IFFT modulation;

Add cyclic prefix module D: be used for every frame data that information source node will obtain and add Cyclic Prefix;

Digital-to-analogue conversion (D/A) module E: be used for information source node digital signal conversion is become analog signal;

Channel module F1～F2: the wireless multipath fading channel between information source node and 2 via nodes;

Analog-to-digital conversion (A/D) module G1～G2: be used for each via node the analog signal that receives is transformed into digital signal;

Remove cyclic prefix module H1～H2: be used for each via node Cyclic Prefix is removed;

Signal processing module I1～I2: each via node is done the corresponding linear processing to receiving data, is used for distributed Space Time Coding;

Add cyclic prefix module J1～J2: be used for each via node the data after handling are added new Cyclic Prefix;

D/A module K1～K2: be used for each via node digital signal conversion is become analog signal;

Wireless multipath fading channel between channel module L1～L2:2 via node and information destination node;

A/D module M: be used for information destination node the analog signal that receives is transformed into digital signal;

Timing error estimation module N: be used for information destination node and estimate relative timing error between the repeated link of concrete different via node correspondences;

Feedback module O: be used for information destination node with feedback information such as timing errors to information source node;

Remove cyclic prefix module P: Cyclic Prefix is removed;

FFT module Q: be used for information destination node the blocks of data that receives is carried out the FFT computing;

Decoding module R: be used for information destination node each subcarrier data is carried out maximum-likelihood decoding;

Stay of two nights module S: output judgement symbol.

2. by the described system of claim 1, it is characterized in that described information source node, via node and information destination node all have only an antenna, and transceive data simultaneously; Described via node adopts the amplification forward collaboration transmission technology.

3. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty,

It is characterized in that comprising step:

1) information destination node estimates link by the timing error estimation module: information source node → via node 1 → information destination node and link: the relative timing error between information source node → via node 2 → information destination node;

2) feedback module of information destination node is with the relative timing Error Feedback that obtains in the step 1) cyclic prefix module that adds to each via node;

3) information source node is provided with the power partition coefficient that requires to determine information source node and via node according to system;

4) information source node is encoded to the character data that will transmit by coding module;

5) information source node is added Cyclic Prefix by adding cyclic prefix module to the data after encoding, and multiply by power partition coefficient after the IFFT modulation, and launches in first time slot;

6) receive data as the receiving terminal of via node in first time slot, remove and do corresponding linear behind its Cyclic Prefix and handle and be used for distributed Space Time Coding, add new Cyclic Prefix, launch in second time slot then according to power amplification coefficient power amplification ratio;

7) receive data as the receiving terminal of information destination node in second time slot, to after receiving data and removing Cyclic Prefix, transmission course when finishing whole distributed space after FFT module, decoding module and the stay of two nights module.

4. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3, it is characterized in that: in step 1), the timing error estimation module adopts the auxiliary method of training sequence to estimate link: information source node → via node 1 → information destination node and link: the relative timing error τ between information source node → via node 2 → information destination node.Estimated relative timing error r is taken as the integral multiple of character data length.

5. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3, it is characterized in that: in step 3), information source node is provided with the power partition coefficient p that requires to determine information source node and via node according to system ₁And p ₂

6. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3, it is characterized in that: in step 4), coding module is encoded to source data in the mode of piece.Length is that the data block of N can be expressed as behind continuous two codings:

x ₁=[x _0,1x _1,1X _N-1,1] ^TAnd x ₂=[x _0,2x _N-1,2X _1,2] ^T, x wherein _{I, j}Be j ∈ 1, the i ∈ of 2} data block 0,1 ..., N-1} character data, () ^T, () ^*() ^HRepresent vector or transpose of a matrix, conjugation, conjugate transpose computing respectively successively.

7. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3 is characterized in that: in step 5), and the 2nd data block x ₂After the IFFT modulation, further be treated to P (F ^*x ₂) ^*, P represents contrary cycle shift operation, F is a normalization FFT matrix.

8. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3, it is characterized in that: in step 6), add circulating prefix-length and be not shorter than relative timing error τ and maximum multipath tap number sum.

9. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 3 is characterized in that: in step 6), { 1, continuous two block signals that 2} via node receives can be expressed as i ∈ $y_{i1}=H_{\mathrm{SRi}}{F}^{*}{x}_1\sqrt{p_1}+n_{i1}$ With $y_{i2}=H_{\mathrm{SRi}}P{\left(F^{*}{x}_2\right)}^{*}\sqrt{p_1}+n_{i2},$ H wherein _SRiFor information source node and i ∈ 1, the channel matrix between 2} via node, n _I1And n _I2Be i ∈ 1, the white noise of unit power in 2} continuous two data block of via node.For carrying out distributed Space Time Coding, the 1st via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{p_1+1}}{y}_{11}$ With $-\sqrt{\frac{p_2}{p_1+1}}{y}_{12},$ The 2nd via node receives data block to continuous two and processes the formation repeating signal: $\sqrt{\frac{p_2}{p_1+1}}P{y}_{22}^{*}$ With $\sqrt{\frac{p_2}{p_1+1}}P{y}_{21}^{*}.$

10. transmission method when being used for the asynchronous amplification forward collaboration of broadband wireless sensor network trunk node communication empty as claimed in claim 5, it is characterized in that: in step 7), the time that the FFT computing begins is as the criterion with the repeating signal that early arrives.

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