CN102307163A - Channel estimating method based on circulation orthogonal sequence in multi-relay cooperative communication system - Google Patents

Channel estimating method based on circulation orthogonal sequence in multi-relay cooperative communication system Download PDF

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CN102307163A
CN102307163A CN201110187832A CN201110187832A CN102307163A CN 102307163 A CN102307163 A CN 102307163A CN 201110187832 A CN201110187832 A CN 201110187832A CN 201110187832 A CN201110187832 A CN 201110187832A CN 102307163 A CN102307163 A CN 102307163A
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channel
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training sequence
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CN102307163B (en
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张志鹏
钟杰
赵民建
秦博雅
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Zhejiang University ZJU
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Abstract

The invention discloses a channel estimating method based on circulation orthogonal sequence in a multi-relay cooperative communication system, through which reliability and efficiency of the multi-relay cooperative communication can be increased obviously. In the designed relay system, the source node broadcast transmits a channel training sequence having circulation orthogonal characteristics, each relay node forwards the received channel training sequence to the target node after circulation shift of different intervals. Through the signal received by the target node is superimposition of the channel training sequences forwarded by each relay, the target node can accurately estimate the source node-target node channel through each relay by using the orthogonality among the training sequences forwarded by each relay. The method has the advantages that high-precision channel estimation can be finished with low operation complexity and low training time cost, and the estimation error and the time cost will not be increased as the increase of the relay number, and the method is suitable for the cooperative communication system having a large number of relays.

Description

In many relayings communication for coordination system based on the channel estimation methods of cyclic orthogonal experiment sequence
Technical field
The present invention relates to the digital communication signal process field, relate in particular in a kind of many relayings communication for coordination system channel estimation methods based on the cyclic orthogonal experiment sequence.
Background technology
In radio communication, the frequency selective fading that multipath channel causes can influence the reliability of signal transmission, worsens transmission performances, when signal bandwidth increases frequency selective fading to influence meeting more obvious.In addition, the situation of deep fade in radio communication, also can occur, make that communication link is difficult to set up or keep.Thereby the ability of traditional end-to-end a single aerial system opposing multipath and deep fade system is limited, is difficult to satisfy the requirement of the two-forty high bandwidth of next generation mobile communication.Thereby introduced multiaerial system (MIMO); Its diversity gain that provides can promote the reliability of transmitting under the multipath channel effectively, has adopted aerial array but be based in the diversity system of many antennas, has increased the utility system size; Improved cost, increased it and realized difficulty.In order to overcome this shortcoming, introduced communication for coordination system (seeing " Cooperative Communication in Wireless Networks " in IEEE Communications Magazine 2004) based on many relayings.The antenna at terminal that is distributed in the space diverse location based on the communication for coordination system utilization of many relayings is collaborative each other, under the situation of not obvious increase terminal implementation complexity, realizes dividing collection.
In the communication for coordination based on many relayings, channel condition information (CSI) plays crucial effects to the strategy and the performance of relay transmission.Existing channel estimation methods has two kinds under the collaborative pattern of at present simple forward pass relaying: the one, and time division multiplexing mode (TDM); Each via node is forwarded to destination node with the channel training word of source node broadcasting successively, and destination node estimates the trunk channel through each relaying successively; The 2nd, frequency division multiplexing mode (FDM); Each via node multiply by in the training pilot tone that will receive on the frequency domain transmits each sub carrier group to destination node after different comb functions obtains the different subcarriers group; Destination node is at the channel that estimates on the frequency domain on each groups of subcarriers; The trunk channel of each relaying of acquisition process after interior the inserting (" Channel Estimation Based on Pilot Frequency Division Multiplexing for Distributed Space-Frequency Coded Cooperative Communication System " in IEEE Vehicular Technology Conference (VTC), 2010-Spring).Time division multiplexing mode is if need adopt long training sequence during the estimated accuracy of having relatively high expectations, but efficient can reduce along with the increase of relaying quantity greatly, if want guaranteed efficiency then need adopt short training sequence, estimated accuracy is reduction therefore; Insert in needing in the frequency division multiplexing mode to adopt, in the interpolated error increase more for a long time of relaying quantity, decreased performance is obvious.
In order to be adapted to actual communication for coordination system, to the deficiency of channel estimation methods above-mentioned, the present invention has designed a kind of high efficiency, high-precision channel estimation methods.This method is based on the training sequence with cyclic orthogonal experiment characteristic, and a plurality of relayings carry out cyclic shift to the training sequence of the source node that receives, make up the channel training word with good orthogonal property at each relay well.This method has lower computational complexity, and time overhead and evaluated error are all less and can not be applicable to actual relaying communication for coordination system more because of the increasing rapidly of the increase of relaying quantity.
Summary of the invention
The objective of the invention is to overcome the deficiency of channel estimation technique in existing many relayings communication for coordination system, the channel estimation methods based on the cyclic orthogonal experiment training sequence is provided in a kind of many relayings communication for coordination system.This method has lower computational complexity, higher efficient and higher precision.
Step based on the channel estimation methods of cyclic orthogonal experiment sequence in many relayings communication for coordination system is following:
1) source node adopts broadcast mode whole individual via node transmitting channel training sequences in system, and the channel training sequence has the cyclic orthogonal experiment characteristic;
2) after each via node received the channel training sequence, each via node was confirmed the shift intervals on this via node, the channel training sequence that receives with this interval cyclic shift and amplify after, transmit the channel training sequence after amplifying to destination node; The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself, the 2nd, this via node and have the transmission time delay difference
Figure 2011101878325100002DEST_PATH_IMAGE004
that exists between the via node in short transmission path;
3) signal that receives of destination node is the stack of the channel training sequence transmitted from each relaying, and the channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node;
4) all the synthetic total trunk channel of
Figure 801846DEST_PATH_IMAGE002
individual trunk channel is vectorial for destination node; With total trunk channel vector as a variable to be estimated; Destination node is utilized the orthogonality between the training sequence that each via node transmits; Accurately estimate total trunk channel vector, the estimation of each trunk channel is a vectorial fragment of total trunk channel of estimating.
The expression formula of described channel training sequence is:
Figure 2011101878325100002DEST_PATH_IMAGE006
，
Insert Cyclic Prefix before in channel training sequence and eliminate inter-block-interference.The cyclic orthogonal experiment characteristic is meant the training sequence
Figure 532035DEST_PATH_IMAGE008
that length is
Figure 2011101878325100002DEST_PATH_IMAGE010
; Cross correlation value between the sequence of its different interval cyclic shift is zero, promptly
Figure 2011101878325100002DEST_PATH_IMAGE012
Wherein, Computing
Figure 2011101878325100002DEST_PATH_IMAGE014
representes the vector of length for
Figure 249456DEST_PATH_IMAGE010
carried out the cyclic shift of
Figure 2011101878325100002DEST_PATH_IMAGE016
individual symbol, and
Figure 2011101878325100002DEST_PATH_IMAGE018
representes the energy of channel training sequence.
Described step 2) after each via node receives the channel training sequence in; Each via node is confirmed the shift intervals on this via node; The channel training sequence that receives with this interval cyclic shift is also amplified; Channel training sequence after destination node transmit to be amplified is: different via nodes are different to the channel training sequence cyclic shift that receives at interval; Wherein individual relaying cyclic shift is spaced apart
Figure 2011101878325100002DEST_PATH_IMAGE022
;
Figure DEST_PATH_IMAGE024
is greater than the maximum multipath time delay
Figure DEST_PATH_IMAGE026
of trunk channel; Trunk channel refers to source node through the channel of certain via node to destination node, and its maximum multipath time delay
Figure 392468DEST_PATH_IMAGE026
is owing to the multipath transmission causes.Before new sequence, insert Cyclic Prefix again, amplify the back and transmit this sequence to destination node.
The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself; The 2nd, this via node and have the transmission time delay difference
Figure 206840DEST_PATH_IMAGE004
that exists between the via node in short transmission path, with the vector of
Figure 216253DEST_PATH_IMAGE020
individual via node to the multipath channel of destination node is defined as
Figure DEST_PATH_IMAGE028
dimension:
Figure DEST_PATH_IMAGE030
Trunk channel may be defined as the linear convolution of source-trunk channel and relaying-purpose channel; I.e.
Figure DEST_PATH_IMAGE032
; Wherein
Figure DEST_PATH_IMAGE034
is the time domain impulse response of the multipath channel of the individual via node of source node to the
Figure 47068DEST_PATH_IMAGE020
, and maximum multipath time delay
Figure 245968DEST_PATH_IMAGE026
can be expressed as
Figure DEST_PATH_IMAGE036
，
Wherein
Figure DEST_PATH_IMAGE038
is the length of the multipath channel of the individual via node of source node to the , be the length of individual via node to the multipath channel of destination node.
Described step 3) is: when adopting frequency-domain equalization technology; Before the sequence that each node sends Cyclic Prefix is arranged all; Linear convolution is equivalent to circular convolution; The signal that destination node receives is expressed as
Figure DEST_PATH_IMAGE044
Wherein
Figure DEST_PATH_IMAGE046
expression circular convolution computing;
Figure DEST_PATH_IMAGE048
is the amplification coefficient of
Figure 597294DEST_PATH_IMAGE020
individual relaying;
Figure 2011101878325100002DEST_PATH_IMAGE050
is total equivalent noise on the destination node; The signal that destination node receives is the stack from the channel training sequence of each relaying forwarding; The channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node.
Described step 4) is: destination node is utilized the orthogonality between the training sequence that each via node transmits, and accurately estimates total trunk channel vector, and the estimation of each trunk channel is a fragment of total trunk channel vector of estimating.
The equivalent signal matrix that the definition source node sends to
Figure 271989DEST_PATH_IMAGE020
individual via node does
Figure 2011101878325100002DEST_PATH_IMAGE052
Expansion relays channel
Figure 2011101878325100002DEST_PATH_IMAGE054
length is to
Figure 421472DEST_PATH_IMAGE026
; During promptly as ;
Figure DEST_PATH_IMAGE058
arranged; With the part of amplification coefficient as trunk channel
Destination node receives the signal obtained
Figure DEST_PATH_IMAGE060
is expressed as
Figure DEST_PATH_IMAGE062
-dimensional vector
Figure DEST_PATH_IMAGE064
;
Definition
Figure 661436DEST_PATH_IMAGE002
the total composition of a relay channel relay channel vector
Figure DEST_PATH_IMAGE066
;
Defining total signal matrix is
Figure DEST_PATH_IMAGE068
;
Then utilize
Figure DEST_PATH_IMAGE070
and
Figure 27696DEST_PATH_IMAGE064
that define can obtain the least square (LeastSqare of total trunk channel vector
Figure DEST_PATH_IMAGE072
; LS) estimate
After the first
Figure 240502DEST_PATH_IMAGE020
relay nodes relay channel, the LS estimate of the total estimated value of the relay channel vector a fragment
。
 
The advantage of this invention is under lower computational complexity and less training time expense, to accomplish high-precision channel estimating; And estimated accuracy and time overhead can not worsen along with the increase of relaying quantity, are applicable to a fairly large number of communication for coordination of relaying system.
Description of drawings
Fig. 1 is many relayings communication for coordination system model;
Fig. 2 is many relayings communication for coordination system signal variation diagram;
Fig. 3 is the related procedure that many relayings communication for coordination system carries out channel estimating;
Fig. 4 is in 2 relay systems and 4 relay systems, based on the channel estimation errors of cyclic orthogonal experiment sequence and the evaluated error correlation curve of time division multiplexing method (TDM) and frequency division multiplexing method (FDM).
Embodiment
Step based on the channel estimation methods of cyclic orthogonal experiment sequence in many relayings communication for coordination system is following:
1) source node adopts broadcast mode whole individual via node transmitting channel training sequences in system, and the channel training sequence has the cyclic orthogonal experiment characteristic;
2) after each via node received the channel training sequence, each via node was confirmed the shift intervals on this via node, the channel training sequence that receives with this interval cyclic shift and amplify after, transmit the channel training sequence after amplifying to destination node; The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself, the 2nd, this via node and have the transmission time delay difference
Figure 574160DEST_PATH_IMAGE004
that exists between the via node in short transmission path;
3) signal that receives of destination node is the stack of the channel training sequence transmitted from each relaying, and the channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node;
4) all the synthetic total trunk channel of
Figure 652974DEST_PATH_IMAGE002
individual trunk channel is vectorial for destination node; With total trunk channel vector as a variable to be estimated; Destination node is utilized the orthogonality between the training sequence that each via node transmits; Accurately estimate total trunk channel vector, the estimation of each trunk channel is a vectorial fragment of total trunk channel of estimating.
The expression formula of described channel training sequence is:
Figure 337902DEST_PATH_IMAGE006
，
Insert Cyclic Prefix before in channel training sequence and eliminate inter-block-interference.The cyclic orthogonal experiment characteristic is meant the training sequence that length is
Figure 997871DEST_PATH_IMAGE010
; Cross correlation value between the sequence of its different interval cyclic shift is zero, promptly
Figure 918346DEST_PATH_IMAGE012
Wherein, Computing
Figure 860894DEST_PATH_IMAGE014
representes the vector of length for
Figure 236512DEST_PATH_IMAGE010
carried out the cyclic shift of
Figure 657129DEST_PATH_IMAGE016
individual symbol, and
Figure 316649DEST_PATH_IMAGE018
representes the energy of channel training sequence.
Described step 2) after each via node receives the channel training sequence in; Each via node is confirmed the shift intervals on this via node; The channel training sequence that receives with this interval cyclic shift is also amplified; Channel training sequence after destination node transmit to be amplified is: different via nodes are different to the channel training sequence cyclic shift that receives at interval; Wherein
Figure 430099DEST_PATH_IMAGE020
individual relaying cyclic shift is spaced apart
Figure 293013DEST_PATH_IMAGE022
;
Figure 517321DEST_PATH_IMAGE024
is greater than the maximum multipath time delay
Figure 267233DEST_PATH_IMAGE026
of trunk channel; Trunk channel refers to source node through the channel of certain via node to destination node, and its maximum multipath time delay is owing to the multipath transmission causes.Before new sequence, insert Cyclic Prefix again, amplify the back and transmit this sequence to destination node.
The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself; The 2nd, this via node and have the transmission time delay difference
Figure 901794DEST_PATH_IMAGE004
that exists between the via node in short transmission path, with the vector of
Figure 929793DEST_PATH_IMAGE020
individual via node to the multipath channel of destination node is defined as
Figure 298326DEST_PATH_IMAGE028
dimension:
Figure 487999DEST_PATH_IMAGE030
Trunk channel may be defined as the linear convolution of source-trunk channel and relaying-purpose channel; I.e.
Figure 325505DEST_PATH_IMAGE032
; Wherein
Figure 891615DEST_PATH_IMAGE034
is the time domain impulse response of the multipath channel of the individual via node of source node to the
Figure 902207DEST_PATH_IMAGE020
, and maximum multipath time delay
Figure 262781DEST_PATH_IMAGE026
can be expressed as
Figure 587583DEST_PATH_IMAGE036
，
Wherein
Figure 957385DEST_PATH_IMAGE038
is the length of the multipath channel of the individual via node of source node to the
Figure 34931DEST_PATH_IMAGE020
,
Figure 831986DEST_PATH_IMAGE040
be the length of individual via node to the multipath channel of destination node.
Described step 3) is: when adopting frequency-domain equalization technology; Before the sequence that each node sends Cyclic Prefix is arranged all; Linear convolution is equivalent to circular convolution; The signal that destination node receives
Figure 551997DEST_PATH_IMAGE042
is expressed as
Figure 251094DEST_PATH_IMAGE044
Wherein
Figure 219050DEST_PATH_IMAGE046
expression circular convolution computing;
Figure 252865DEST_PATH_IMAGE048
is the amplification coefficient of
Figure 964469DEST_PATH_IMAGE020
individual relaying; is total equivalent noise on the destination node; The signal that destination node receives is the stack from the channel training sequence of each relaying forwarding; The channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node.
Described step 4) is: destination node is utilized the orthogonality between the training sequence that each via node transmits, and accurately estimates total trunk channel vector, and the estimation of each trunk channel is a fragment of total trunk channel vector of estimating.
The equivalent signal matrix that the definition source node sends to
Figure 155465DEST_PATH_IMAGE020
individual via node does
Figure 676576DEST_PATH_IMAGE052
Expansion relays channel length is to
Figure 597051DEST_PATH_IMAGE026
; During promptly as
Figure 844493DEST_PATH_IMAGE056
;
Figure 915217DEST_PATH_IMAGE058
arranged; With the part of amplification coefficient as trunk channel
Destination node receives the signal obtained is expressed as
Figure 933038DEST_PATH_IMAGE062
-dimensional vector
Figure 413698DEST_PATH_IMAGE064
;
Definition
Figure 706139DEST_PATH_IMAGE002
the total composition of a relay channel relay channel vector
Figure 251652DEST_PATH_IMAGE066
;
Defining total signal matrix is
Figure 945938DEST_PATH_IMAGE068
;
Then utilize
Figure 535183DEST_PATH_IMAGE070
and
Figure 767450DEST_PATH_IMAGE064
that define can obtain the least square (LeastSqare of total trunk channel vector
Figure 162659DEST_PATH_IMAGE072
; LS) estimate
After the first
Figure 737177DEST_PATH_IMAGE020
relay nodes relay channel, the LS estimate of the total estimated value of the relay channel vector a fragment
。
Embodiment
In the communication for coordination system of 2 or 4 via nodes; Application is based on the channel estimation methods of cyclic orthogonal experiment sequence: source node is quasistatic multipath Rayleigh channel to each via node, each via node to the channel of destination node; Maximum multipath postpone be 5 , then through the whole source-purpose channel of each relaying be maximum multipath postpone be 10
Figure 229579DEST_PATH_IMAGE078
quasistatic multipath Rayleigh channel.
If the symbol rate of analogue system is 5MHz; Then 10
Figure 675472DEST_PATH_IMAGE078
multidiameter corresponding postpone 50 symbols; Adopting the length of cyclic orthogonal experiment training sequence is 256, is to obtain the efficiency of transmission comparable with it: time-division multiplexing method (TDM) adopts length respectively when 2 relayings and 4 relayings be 128 and 64 channel training sequence; Frequency-division multiplexing method (FDM) adopts the pilot tone that comprises 256 number of sub-carrier.It is that the Cyclic Prefix of 32 symbols is to eliminate inter-block-interference that length is arranged before each training sequence of each node transmission.
The algorithm that proposes in the diplomatic copy invention under these conditions, with the mean square error of this channel estimation method (Mean Square Error, MSE) MSE with TDM and FDM method contrasts, comparing result is shown in accompanying drawing 4.From accompanying drawing 4, can find out:
1) algorithm that proposes of the present invention has less evaluated error, in 2 relay systems evaluated error of this algorithm be TDM and FDM evaluated error 1/2; In 4 relay systems evaluated error of this algorithm be merely TDM and FDM evaluated error 1/4;
2) evaluated error of the algorithm of the present invention's proposition can obviously not increase because of the increase of relaying quantity, and in TDM and the FDM method, the evaluated error of 4 relay systems is 2 times of 2 relay system evaluated errors;
3) in the FDM method, evaluated error does not reduce along with the increase of signal to noise ratio always, has an error platform.And there is not this problem in the algorithm that the present invention proposes.
The above is merely a preferred embodiment of the present invention, does not constitute any restriction of the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (5)

  1. In the system of relaying communication for coordination more than a kind based on the channel estimation methods of cyclic orthogonal experiment sequence, it is characterized in that its step is following:
    1) source node adopts broadcast mode whole
    Figure 2011101878325100001DEST_PATH_IMAGE001
    individual via node transmitting channel training sequences in system, and the channel training sequence has the cyclic orthogonal experiment characteristic;
    2) after each via node received the channel training sequence, each via node was confirmed the shift intervals on this via node, the channel training sequence that receives with this interval cyclic shift and amplify after, transmit the channel training sequence after amplifying to destination node; The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself, the 2nd, this via node and have the transmission time delay difference
    Figure 517525DEST_PATH_IMAGE002
    that exists between the via node in short transmission path;
    3) signal that receives of destination node is the stack of the channel training sequence transmitted from each relaying, and the channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node;
    4) all the synthetic total trunk channel of
    Figure 246447DEST_PATH_IMAGE001
    individual trunk channel is vectorial for destination node; With total trunk channel vector as a variable to be estimated; Destination node is utilized the orthogonality between the training sequence that each via node transmits; Accurately estimate total trunk channel vector, the estimation of each trunk channel is a vectorial fragment of total trunk channel of estimating.
  2. According in a kind of many relayings communication for coordination system described in the claim 1 based on the channel estimation methods of cyclic orthogonal experiment sequence, it is characterized in that the expression formula of described channel training sequence is:
    Figure 2011101878325100001DEST_PATH_IMAGE003
    ，
    Insert Cyclic Prefix before in channel training sequence
    Figure 13677DEST_PATH_IMAGE004
    and eliminate inter-block-interference; The cyclic orthogonal experiment characteristic is meant the training sequence that length is ; Cross correlation value between the sequence of its different interval cyclic shift is zero, promptly
    Wherein, Computing
    Figure 2011101878325100001DEST_PATH_IMAGE007
    representes the vector of length for carried out the cyclic shift of individual symbol, and
    Figure 2011101878325100001DEST_PATH_IMAGE009
    representes the energy of channel training sequence.
  3. According in a kind of many relayings communication for coordination system described in the claim 1 based on the channel estimation methods of cyclic orthogonal experiment sequence; It is characterized in that described step 2) in after each via node receives the channel training sequence; Each via node is confirmed the shift intervals on this via node; The channel training sequence that receives with this interval cyclic shift is also amplified; Channel training sequence after destination node transmit to be amplified is: different via nodes are different to the channel training sequence cyclic shift that receives at interval; Wherein
    Figure 2011101878325100001DEST_PATH_IMAGE011
    individual relaying cyclic shift is spaced apart
    Figure 154415DEST_PATH_IMAGE012
    ; is greater than the maximum multipath time delay of trunk channel; Trunk channel refers to source node through the channel of certain via node to destination node; Its maximum multipath time delay
    Figure 721848DEST_PATH_IMAGE014
    is owing to the multipath transmission causes; Before new sequence, insert Cyclic Prefix again; Amplify the back and transmit this sequence to destination node; The channel that each via node is forwarded to destination node comprises two parts; The one, the time domain impulse response of this channel itself; The 2nd, this via node and have the transmission time delay difference
    Figure 80148DEST_PATH_IMAGE002
    that exists between the via node in short transmission path, with the vector of
    Figure 552718DEST_PATH_IMAGE011
    individual via node to the multipath channel of destination node is defined as
    Figure 2011101878325100001DEST_PATH_IMAGE015
    dimension:
    Trunk channel may be defined as the linear convolution of source-trunk channel and relaying-purpose channel; I.e.
    Figure 2011101878325100001DEST_PATH_IMAGE017
    ; Wherein
    Figure 217497DEST_PATH_IMAGE018
    is the time domain impulse response of the multipath channel of the individual via node of source node to the
    Figure 441805DEST_PATH_IMAGE011
    , and maximum multipath time delay can be expressed as
    Figure 2011101878325100001DEST_PATH_IMAGE019
    ，
    Wherein
    Figure 912286DEST_PATH_IMAGE020
    is the length of the multipath channel of the individual via node of source node to the ,
    Figure 2011101878325100001DEST_PATH_IMAGE021
    be the length of
    Figure 38298DEST_PATH_IMAGE011
    individual via node to the multipath channel of destination node.
  4. According in a kind of many relayings communication for coordination system described in the claim 1 based on the channel estimation methods of cyclic orthogonal experiment sequence; It is characterized in that described step 3) is: when adopting frequency-domain equalization technology; Before the sequence that each node sends Cyclic Prefix is arranged all; Linear convolution is equivalent to circular convolution; The signal that destination node receives
    Figure 157564DEST_PATH_IMAGE022
    is expressed as
    Figure 2011101878325100001DEST_PATH_IMAGE023
    Wherein
    Figure 534187DEST_PATH_IMAGE024
    expression circular convolution computing;
    Figure 2011101878325100001DEST_PATH_IMAGE025
    is the amplification coefficient of individual relaying;
    Figure 937804DEST_PATH_IMAGE026
    is total equivalent noise on the destination node; The signal that destination node receives is the stack from the channel training sequence of each relaying forwarding; The channel training sequence of destination node utilization stack will be passed through the source node of certain via node and estimated as a whole to the trunk channel of destination node.
  5. According in a kind of many relayings communication for coordination system described in the claim 1 based on the channel estimation methods of cyclic orthogonal experiment sequence; It is characterized in that described step 4) is: destination node is utilized the orthogonality between the training sequence that each via node transmits; Accurately estimate total trunk channel vector; The estimation of each trunk channel is a vectorial fragment of total trunk channel of estimating, the equivalent signal matrix that the definition source node sends to
    Figure 239472DEST_PATH_IMAGE011
    individual via node does
    Figure 2011101878325100001DEST_PATH_IMAGE027
    Expansion relays channel
    Figure 288462DEST_PATH_IMAGE028
    length is to
    Figure 613264DEST_PATH_IMAGE014
    ; During promptly as
    Figure 2011101878325100001DEST_PATH_IMAGE029
    ;
    Figure 170016DEST_PATH_IMAGE030
    arranged; With the part of amplification coefficient as trunk channel
    Destination node receives the signal obtained
    Figure 2011101878325100001DEST_PATH_IMAGE031
    is expressed as -dimensional vector
    Figure 2011101878325100001DEST_PATH_IMAGE033
    ;
    Definition
    Figure 504273DEST_PATH_IMAGE001
    a relay channel components of the total relay channel vector
    Figure 113109DEST_PATH_IMAGE034
    ;
    Defining total signal matrix is ;
    Then utilize and
    Figure 421916DEST_PATH_IMAGE033
    that define can obtain the least square (LeastSqare of total trunk channel vector
    Figure 2011101878325100001DEST_PATH_IMAGE037
    ; LS) estimate
    Figure 327555DEST_PATH_IMAGE038
    After the first
    Figure 112103DEST_PATH_IMAGE011
    relay nodes relay channel, the LS estimate of the total estimated value of the relay channel vector
    Figure 823707DEST_PATH_IMAGE038
    a fragment
    Figure 2011101878325100001DEST_PATH_IMAGE039
    。
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CN104052690A (en) * 2014-05-09 2014-09-17 中国电子科技集团公司第七研究所 Frequency synchronization method for cooperative communication system
CN104052580A (en) * 2014-06-25 2014-09-17 西安交通大学 Multi-node collaborative signal transmitting and receiving method used in wireless sensor network
CN111614584A (en) * 2020-05-20 2020-09-01 西安电子科技大学 Transform domain adaptive filtering channel estimation method based on neural network
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