CN102263582B - Cooperative diversity system beamforming method and device - Google Patents
Cooperative diversity system beamforming method and device Download PDFInfo
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Abstract
The invention discloses a kind of cooperative diversity system beamforming method and device, the above method includes：One TDMA frame is divided into three subframes, the shared subframe of two user terminals carries out information transfer；The signal that three subframes of one TDMA frame are received and sent is determined according to trunk protocol；The combined signal received according to equivalent channel model to different subframes carries out the final reception of processing determination and sends signal；The cooperative diversity system beam forming of user terminal is completed according to final reception and transmission signal.The technical scheme provided by the present invention, solves the problem of existing cooperative diversity system capacity is not high, and then reached raising power system capacity effect.
Description
Technical field
The present invention relates to the communications field, in particular to a kind of cooperative diversity system beamforming method and device.
Background technology
In follow-on broadband wireless communication network, how solve in cordless communication network in current radio communication system
Support bigger bandwidth turns into improve inter-cell user terminal throughput and user terminal average throughput under bandwidth in system
One key factor is simultaneously faced with formidable challenges.
In wireless communications, transmitting diversity is the effective technology of anti-multipath fading.However, due to power, volume, expense with
And the limitation such as hardware complexity, wireless terminal may be only with single antenna.Therefore, cooperative diversity technique arises at the historic moment, and its is main
Thought is to allow multiple single antenna terminals to constitute a virtual multi-antenna array, to obtain transmitting diversity.When two wireless terminals
When cooperating with each other, a terminal first intercepts the transmission of other side, then on different orthogonal sub-channels (time, frequency, code word or
Space) retransmit reception signal or according to the redundancy for receiving signal of change.When two users cooperate, the angle from base station is
System is equivalent to a multiple access access channel.In order to isolate the information of each user in base station end, different multiple access can be used
Access protocol (different orthogonal sub-channels division methods), such as, CDMA (Code-Division Multiple Access, code
Point multiple access) agreement, TDMA (Time-Division Multiple Access, time division multiple acess) agreement, FDMA (Frequency-
Division Multiple Access, frequency division multiple access) agreement etc..
But, generally speaking current cooperative diversity system capacity is not high, while there are various problems：
(1) each user can only send information from the orthogonal and in-phase component of PSK modulating systems in cooperative diversity system,
Therefore can only be using BPSK modulation.
(2) antenna amount is limited on base station (BS) and user terminal (UE) in cooperative diversity system.
(3) trunk protocol is single in cooperative diversity system.
(4) tradition AF (Amplify-And-Forward amplifies and forwarded) agreement, DF in cooperative diversity system
(Decode-And-Forward is decoded and forwarded) agreement, SDF (Selection Decode and Forward, selection decoding
And forward) consultation causes systematic function to reduce.
The content of the invention
It is a primary object of the present invention to provide a kind of cooperative diversity system beamforming method and device, at least to solve
One of above mentioned problem.
According to an aspect of the invention, there is provided a kind of cooperative diversity system beamforming method, including：By one
TDMA frame is divided into three subframes, and the shared subframe of two user terminals carries out information transfer；One is determined according to trunk protocol
The signal that three subframes of TDMA frame are received and sent；Entered according to the combined signal that equivalent channel model is received to different subframes
The final reception of row processing determination and transmission signal；The collaboration diversity system of user terminal is completed according to final reception and transmission signal
System beam forming.
Trunk protocol includes at least one of：AF agreements, DF agreements, SDF agreements, the SDF using base station feedback information
Agreement, wherein, included using the SDF agreements of base station feedback information：If decoding is correct mutually at two collaboration user ends, the 3rd
Buddy information is sent in subframe mutually；If a user terminal decoding is correct, another decoding error then decodes correct user
End sends buddy information in the 3rd subframe, and the user terminal of decoding error keeps silent；If two equal decoding errors of user terminal,
Then retransmit the information of oneself in the 3rd subframe.
Equivalent channel model includes：(how defeated Multiple Input Multiple Output, multi input is for virtual MIMO
Go out) system.
When trunk protocol is the SDF agreements using base station feedback information, completed according to final reception and transmission signal
The cooperative diversity system beam forming of user terminal includes：Collaboration diversity condition is determined according to subscriber channel condition；According to MMSE
(Minimum Mean Square Error, Minimum Mean Square Error) criterion obtains the cost function of beam forming；According to cost function
Obtain the optimal wiener solution of beam forming weight；According to the collaboration diversity condition of determination, the optimal wiener solution of beam forming weight and most
Whole reception and transmission signal completes the cooperative diversity system beam forming of user terminal.
Collaboration diversity condition includes one below：Decoding is correct mutually for first user terminal and second user end, in the 3rd son
Frame, first user terminal sends x2, second user end sends x1, now,The decoding of first user terminal is correct
But second user end decoding error, in the 3rd subframe, the first user terminal sends x2, second user end keeps silent；Second user
End decodes correct but the first user terminal decoding error, and in the 3rd subframe, second user end sends x1, the first user terminal keep it is quiet
It is silent；The equal decoding failure of first user terminal and second user end, in the 3rd subframe, the first user terminal and second user end are retransmitted respectively
The information x of oneself1And x2, now,Wherein, x1It is the first user terminal at the first subframe nth symbol interval
The signal of interior transmission, x2The signal sent for second user end in the second subframe nth symbol interval,WithUsed for first
The estimate for the buddy information that family end and second user end are sent respectively in the 3rd subframe.
According to another aspect of the present invention there is provided a kind of cooperative diversity system beam forming device, including：Sub-frame division
Module, for a TDMA frame to be divided into three subframes, makes the shared subframe of two user terminals carry out information transfer；Signal
Determining module, for determining the signal that three subframes of a TDMA frame are received and sent according to trunk protocol；Combined Treatment mould
Block, the combined signal for being received according to equivalent channel model to different time-gap carries out processing and determines final reception and transmission
Signal；Beamforming block, for according to final reception and send signal complete user terminal cooperative diversity system wave beam into
Shape.
Trunk protocol includes at least one of：AF agreements, DF agreements, SDF agreements, the SDF using base station feedback information
Agreement, wherein, included using the SDF agreements of base station feedback information：If decoding is correct mutually at two collaboration user ends, the 3rd
Buddy information is sent in subframe mutually；If a user terminal decoding is correct, another decoding error then decodes correct user
End sends buddy information in the 3rd subframe, and the user terminal of decoding error keeps silent；If two equal decoding errors of user terminal,
Then retransmit the information of oneself in the 3rd subframe.
Equivalent channel model includes：(how defeated Multiple Input Multiple Output, multi input is for virtual MIMO
Go out) system.
Beamforming block includes：Diversity condition determining unit, for being to utilize base station feedback information in trunk protocol
During SDF agreements, collaboration diversity condition is determined according to subscriber channel condition；Cost function determining unit, for according to MMSE criterions
Obtain the cost function of beam forming；Optimal wiener solution determining unit, for obtaining beam forming weight most according to cost function
Excellent wiener solution；Beam shaping elements, for the collaboration diversity condition according to determination, the optimal wiener solution of beam forming weight and final
Reception and send signal complete user terminal cooperative diversity system beam forming.
Collaboration diversity condition includes one below：Decoding is correct mutually for first user terminal and second user end, in the 3rd son
Frame, first user terminal sends x2, second user end sends x1, now,The decoding of first user terminal is correct
But second user end decoding error, in the 3rd subframe, the first user terminal sends x2, second user end keeps silent；Second user
End decodes correct but the first user terminal decoding error, and in the 3rd subframe, second user end sends x1, the first user terminal keep it is quiet
It is silent；The equal decoding failure of first user terminal and second user end, in the 3rd subframe, the first user terminal and second user end are retransmitted respectively
The information x of oneself1And x2, now,Wherein, x1It is the first user terminal at the first subframe nth symbol interval
The signal of interior transmission, x2The signal sent for second user end in the second subframe nth symbol interval,WithUsed for first
The estimate for the buddy information that family end and second user end are sent respectively in the 3rd subframe.
By the present invention, three subframes are divided into using by a TDMA frame, a subframe is shared by two user terminals and enters
Row information is transmitted, and is finally completed by corresponding trunk protocol and equivalent channel model the side of cooperative diversity system beam forming
Case, solves the problem of existing cooperative diversity system capacity is not high, and then reached raising power system capacity effect.
Brief description of the drawings
Accompanying drawing described herein is used for providing a further understanding of the present invention, constitutes the part of the application, this hair
Bright schematic description and description is used to explain the present invention, does not constitute inappropriate limitation of the present invention.In the accompanying drawings：
Fig. 1 is the flow chart of cooperative diversity system beamforming method according to embodiments of the present invention；
Fig. 2 is illustrated according to cooperative diversity system beam-forming method two users cooperative diversity system of present example
Figure；
Fig. 3 is the TDMA frame in cooperative diversity system beam-forming method two users of present example cooperation framework
With the structural representation of existing TDMA frame；
Fig. 4 is the theory structure block diagram of the cooperative diversity system beam forming according to present example；
Fig. 5 is the flow chart of the cooperative diversity system beam-forming method according to present example；
Fig. 6 is the BER of U1 under channel between the cooperative diversity system beam-forming method different user according to present example
Performance curve (AF)；
Fig. 7 is the BER of U1 under channel between the cooperative diversity system beam-forming method different user according to present example
Performance curve (SDF)；
Fig. 8 is the structured flowchart of cooperative diversity system beam forming device according to embodiments of the present invention.
Embodiment
Describe the present invention in detail below with reference to accompanying drawing and in conjunction with the embodiments.It should be noted that not conflicting
In the case of, the feature in embodiment and embodiment in the application can be mutually combined.
Fig. 1 is the flow chart of cooperative diversity system beamforming method according to embodiments of the present invention.As shown in figure 1, root
Include according to the cooperative diversity system beamforming method of the embodiment of the present invention：
Step S102, three subframes are divided into by a TDMA frame, and the shared subframe of two user terminals carries out information biography
It is defeated；
Step S104, the signal that three subframes of a TDMA frame are received and sent is determined according to trunk protocol；
Step S106, the combined signal received according to equivalent channel model to different subframes carries out processing and determined finally
Receive and send signal；
Step S108, the cooperative diversity system beam forming of user terminal is completed according to final reception and transmission signal.
This fact Example proposes a kind of new TDMA mechanism, in the present embodiment, and a TDMA frame is divided into three sons
Frame.Effectively to utilize system resource, the first user terminal (U1) and second user end (U2) have shared same subframe.In now
Time and bandwidth resources can be shared after transmission, so this division methods bandwidth efficiency is higher.For each user, channel is certainly
2/3 is increased by spending from 1/2, the channel capacity of user can be so greatly improved.From the perspective of base station, the time can be saved
Resource is cooperated for more users, so as to improve power system capacity.
In above-mentioned new TDMA mechanism, existing trunk protocol can all continue application, but in order to overcome existing relaying
Consultation makes the problem of systematic function is reduced, and this preferred embodiment proposes a kind of new trunk protocol.Preferably, above-mentioned relaying association
View can include at least one of：AF agreements, DF agreements, SDF agreements, the SDF agreements using base station feedback information, wherein,
Included using the SDF agreements of base station feedback information：
If decoding is correct mutually at two collaboration user ends, buddy information is sent mutually in the 3rd subframe；
If a user terminal decoding is correct, another decoding error then decodes correct user terminal in the 3rd subframe
Buddy information is sent, the user terminal of decoding error keeps silent；
If two equal decoding errors of user terminal, retransmit the information of oneself in the 3rd subframe.
The difference fed back using the SDF consultations of base station end feedback information according to base station end carries out different processing：If
Decoding is correct mutually for two collaboration users, and they send buddy information in the 3rd time slot；If user's decoding is correct, another
Individual decoding error, the former can send buddy information in the 3rd time slot, but the latter can keep silent；If two with decoding per family
Mistake, to better profit from channel width, base station will notify two users to retransmit the information of oneself by feedback channel, the feedback
Information can be realized by a bit.Above-mentioned new SDF agreements, when channel is poor between user, will not bring performance for cooperation
Loss, because when dual-purpose decoding failure per family, base station can notify two users to retransmit the information of oneself respectively.
Preferably, above-mentioned equivalent channel model can include：Virtual MIMO system.
The corresponding equivalent channel model of different trunk protocols can be otherwise varied, but most cooperative diversity systems can
Virtual mimo system is equivalent to, therefore when from channel model, preferentially from virtual MIMO system.
But during using the above-mentioned SDF agreements by the use of base station feedback information as trunk protocol, follow-up processing needs corresponding
Be changed, in this preferred embodiment illustrate.Preferably, when trunk protocol is the utilization base station feedback information
During SDF agreements, step S108 may further include following processing：
(1) collaboration diversity condition is determined according to subscriber channel condition；
(2) generation of beam forming is obtained according to MMSE (Minimum Mean Square Error, Minimum Mean Square Error) criterion
Valency function；
(3) the optimal wiener solution of beam forming weight is obtained according to cost function；
(4) believed according to the collaboration diversity condition of determination, the optimal wiener solution of beam forming weight and final reception and transmission
Number complete user terminal cooperative diversity system beam forming.
When using the above-mentioned SDF agreements by the use of base station feedback information as trunk protocol, corresponding collaboration diversity condition
It is not just uniquely, when carrying out cooperative diversity system beam forming, to first have to determine corresponding collaboration diversity condition, then
Cost function is obtained again, is generated optimal wiener solution, is finally completed cooperative diversity system beam forming.
Preferably, above-mentioned collaboration diversity condition can be one below：
Decoding is correct mutually for first user terminal and second user end, and in the 3rd subframe, the first user terminal sends x2, second uses
Family end sends x1, now,
First user terminal decodes correct but second user end decoding error, and in the 3rd subframe, the first user terminal sends x2, the
Two user terminals keep silent；
Second user end decodes correct but the first user terminal decoding error, and in the 3rd subframe, second user end sends x1, the
One user terminal keeps silent；
The equal decoding failure of first user terminal and second user end, in the 3rd subframe, the first user terminal and second user end point
The information x of oneself is not retransmitted1And x2, now,
Wherein, x1The signal sent for the first user terminal in the first subframe nth symbol interval, x2For second user end
The signal sent in the second subframe nth symbol interval,WithIt is that the first user terminal and second user end are divided in the 3rd subframe
The estimate for the buddy information not sent.
This preferred embodiment gives a kind of preferably collaboration diversity condition, cover it is all it can happen that.
Above preferred embodiment is described in detail with reference to example.
Two users' diversity cooperative system structure of this example is as shown in Fig. 2 this example is using the new of above-described embodiment proposition
TDMA mechanism.As shown in Figure 3, it is assumed that TDMA frame takes N number of mark space, traditional framework based on TDMA and its corresponding
Send and receive in mode such as Fig. 2 shown in (a).In this TDMA mechanism, a complete TDMA frame is divided into four sons
Frame：First subframe belongs to U1 information, and second subframe belongs to U2 trunk information, in two subsequent subframes, U1 and
U2 role is exchanged.Above-mentioned new TDMA mechanism is as shown such as (b) in Fig. 2, and now a TDMA frame is divided into three
Subframe.From unlike traditional mechanism, U1 and U2 have shared same subframe.Because now relay transmission can be shared time and bandwidth
Resource, this division methods bandwidth efficiency is higher.For each user, the channel free degree increases 2/3 from 1/2, so
The channel capacity of user can be greatly improved.From the perspective of base station, time resource can be saved and cooperated for more users,
So as to improve power system capacity.
Further, in this example, each user can use any modulation system；By two or many antennas of configuration
Base station, which is provided, receives diversity, using the multi-antenna signal processing technology such as beam forming；Using AF and DF and its deformation etc. it is various in
After agreement, including above-mentioned new SDF agreements：If decoding is correct mutually for two collaboration users, they send in the 3rd time slot
The information of partner；If user's decoding is correct, another decoding error, the former can send partner's letter in the 3rd time slot
Breath, but the latter can keep silent；If two use decoding error per family, to better profit from channel width, base station will be by anti-
Feedback two users of channel notification retransmit the information of oneself, and the feedback information can be realized by a bit.
We analyze base station using two antennas, when relaying is using AF and above-mentioned new SDF agreements, cooperative system now
Low-pass equivalent, time discrete channel model.It is assumed that all channels are all frequency-flat declines and quasi-static, i.e., channel fading exists
Kept in one TDMA frame constant.All channels are independent mutually.System is Complete Synchronization.Know complete channel status in base station
Information CSI (Channel State Information, channel condition information), but user do not know.
For convenience of describing, in following expression formula, time variable n is eliminated.The label declaration used is as follows：
ri(j), i ∈ { 1,2, d }, j ∈ { 1,2,3 } represent the reception signal of user or base station in time slot j, ni(j) it is phase
The additive noise answered and interference；rd,i(j), i ∈ { 1,2 }, j ∈ { 1,2,3 } represent i-th antenna connecing in time slot j of base station
The collection of letters number, nd,i(j) it is corresponding noise and interference；hik(j), i, k ∈ { 1,2 }, j ∈ { 1,2,3 } are user i to k in time slot j
Interior channel fading coefficient；hid,k(j), i, k ∈ { 1,2 }, j ∈ { 1,2,3 } be user i to base station antenna k in time slot j
Channel fading coefficient.In statistical significance, hikAnd h (j)id,k(j) it is that average is 0, independent, circle symmetric complex becomes at random
Amount；niAnd n (j)d,i(j) it is also that average is 0, independent, circle symmetric complex stochastic variable, and variance is N0。
In the first time slot, U1 sends signal, U2 and base station received signal.It is assumed that U1 sends x in nth symbol interval1,
Then U2 and the signal of base station reception are respectively：
r2(1)=h12(1)x1+n2(1) (1)
In the second time slot, U1 and U2 role exchange.It is assumed that U2 sends x in nth symbol interval2, similarly, U1
With base station receive signal be respectively：
r1(2)=h21(2)x2+n1(2) (3)
In the 3rd time slot, when U1 and U2 uses different trunk protocols, the information that base station is received also can correspondingly occur
Change.We illustrate by AF and exemplified by putting forward SDF agreements respectively below.
In the 3rd time slot, U1 and U2 are respectively to transmission simultaneously after the signal amplification that is respectively received, i.e.,
Wherein α1And α2It is gain amplification coefficient, it is assumed that transmission signal power normalization is 1, is taken
By (2), (4) and (5) are combined into vector, and make r=[rd(3),rd(2),rd(1)]T, x=[x1,x2]T, then have：
R=Hx+n (6)
Wherein,
It can be seen that from (6), when base station is handled the combined signal that different time-gap is received, the collaboration diversity
System can be equivalent to the virtual MIMO system that one 2 hair 6 is received.
SDF agreements be by basic DF protocol evolutions Lai, therefore we first discuss U1 and U2 use DF trunk protocols
When, the signal that base station is received.Now U1 and U2 sends the estimate of buddy information in the 3rd time slot respectively, i.e.,With
When channel is bad between user, the estimate of mistake is obtained using DF consultations, causes error propagation.And carried
SDF agreements can avoid error propagation, when using this agreement, and the cooperation between two users has four kinds of situations：
1st, situation 1：Decoding is correct mutually by U1 and U2.In time slot three, U1 sends x2, U2 transmissions x1.Now, rd(3) expression
Formula is similar with (7), simply
2nd, situation 2：U1 decodes correct but U2 decoding errors.In time slot three, U1 sends x2, U2 holding silences.Now, rd(3)
Expression formula it is similar with (5), simply α2=0.
3rd, situation 3：U2 decodes correct but U1 decoding errors.In time slot three, U2 sends x1, U1 holding silences.Now, rd(3)
Expression formula it is similar with (5), simply α1=0.
4th, situation 4：The equal decoding failures of U1 and U2.In time slot three, base station notifies U1 and U2 to retransmit the information x of oneself respectively1
And x2.Now, rd(3) expression formula is similar with (7), can be equivalent to
Determine how to carry out cooperative diversity system beam forming in above-mentioned diversity cooperative system below, refer to Fig. 4.
If array input signal is x (n)=[x1(n),x2(n),...,xk(n)]T, each of which component is different user
Fading signal and corresponding noise superposition.Weight w can be selected according to certain criterion so that array output y (n) is similar to the phase
Hope signal d (n).The calculating of weights can be realized by training symbol.When using MMSE criterions, cost function is:
J (w)=E | d (n)-wHx(n)|2} (8)
By (8) expansion, and its gradient vector to w is made to be 0, i.e.,
Therefore, the optimal solution of weights is:
Formula (10) is also referred to as optimal wiener solution.Wherein Rxx=E { x (n) xH(n) } the auto-correlation square for being input vector x (n)
Battle array, rxd=E { x (n) d*(n) it is } input vector x (n) and desired signal d (n) cross-correlation matrix.
In summary, as shown in figure 5, being comprised the following steps according to the cooperative diversity system beam-forming method of this example：
Step S502：Base station determines the system architecture based on TDMA mechanism, and determines three subframes of a TDMA frame；
Step S504：Base station determines with the SDF agreements of base station end feedback information；
Step S506：Base station determines equivalent channel model, and determine according to SDF agreements three subframes of a TDMA frame
The signal for receiving and sending；
Step S508：The combined signal that base station is received to different time-gap carries out the final reception of processing acquisition and sends letter
Number；
Step S510：Base station determines four kinds of collaboration diversity conditions according to subscriber channel condition；
Step S512：Base station obtains the cost function of beam forming according to MMSE criterions；
Step S514：Base station obtains the optimal wiener solution of beam forming weight according to cost function；
Step S516：Base station completes the cooperative diversity system beam forming of user terminal；
In mimo systems, smart antenna (adaptive antenna array) technology can be used.And beam forming is smart antenna
In key technology, it can adaptively track the sense for expecting user, obtain in a particular direction it is maximum receive,
The co-channel interference signal from other directions is eliminated simultaneously.This is by changing weights (the adjustment phase in array on every antenna
Position) come what is realized.In analysis above, virtual MIMO can be equivalent to using cooperative diversity system during different trunk protocols
System, therefore base station can be separated using beam forming technique to the signal of different user.In cooperative system, different user
Channel to base station is separate, and now weighted value needs to adjust the phase and amplitude of signal, the actual effect of weighting simultaneously
Fruit is that peak response is produced to desired signal in virtual signal space, and produces null effect to interference signal direction.
Fig. 6 is U1 BER performance change situations when using AF trunk protocols.It can be seen that when channel between user
When preferably (such as 15dB), cooperation transmission can bring significant performance improvement, such as BER=10-4When, cooperative gain is about 4dB.It is perfect
Channel (channel of noiseless interference) is the limit that this cooperative system can be provided gain between user, in BER=10-4Shi Yuewei
6dB.When channel is poor between user (such as 0dB), the mainly noise of relaying amplification, the so power for the time slot that cooperates is unrestrained
Fei Liao, therefore cooperation can bring partial properties to be lost on the contrary.To avoid similar performance from being lost, improved trunk protocol can be used
Or power distribution mechanism overcomes the influence that channel strip comes between poor user.
Fig. 7 is U1 BER performance change situations when using SDF trunk protocols.It can be seen that believing between user
When road is poor (such as 0dB), cooperation does not bring performance to be lost, because when dual-purpose decoding failure per family, base station can be notified respectively
Two users retransmit the information of oneself.Fig. 5 also illustrates, when channel is preferable and fine between user, the cooperation brought using SDF agreements
Gain is suitable with AF agreements, and can obtain 4 diversity order gains.
Fig. 8 is the structured flowchart of cooperative diversity system beam forming device according to embodiments of the present invention.As shown in figure 8,
Cooperative diversity system beam forming device according to embodiments of the present invention includes：
Sub-frame division module 82, for a TDMA frame to be divided into three subframes, makes two user terminals share a son
Frame carries out information transfer；
Signal determining module 84, is connected to sub-frame division module 82, for determining TDMA frame according to trunk protocol
The signal that three subframes are received and sent；
Combined Treatment module 86, is connected to signal determining module 84, for being connect according to equivalent channel model to different time-gap
The combined signal received carries out the final reception of processing determination and sends signal；
Beamforming block 88, is connected to Combined Treatment module 86, for being completed according to final reception and transmission signal
The cooperative diversity system beam forming of user terminal.
A kind of new TDMA mechanism of said apparatus, in the present embodiment, a TDMA frame can be divided by said apparatus
For three subframes, same subframe have shared by the first user terminal (U1) and second user end (U2).Due to now relay transmission energy
Shared time and bandwidth resources, so this division methods bandwidth efficiency is higher.For each user, the channel free degree is from 1/
2 increase 2/3, can so greatly improve the channel capacity of user.From the perspective of base station, time resource can be saved for more
Many users are cooperated, so as to improve power system capacity.In specific implementation process, said apparatus can be arranged on base station
On.
Preferably, above-mentioned trunk protocol can include at least one of：AF agreements, DF agreements, SDF agreements, utilize base
Stand the SDF agreements of feedback information, wherein, included using the SDF agreements of base station feedback information：
If decoding is correct mutually at two collaboration user ends, buddy information is sent mutually in the 3rd subframe；
If a user terminal decoding is correct, another decoding error then decodes correct user terminal in the 3rd subframe
Buddy information is sent, the user terminal of decoding error keeps silent；
If two equal decoding errors of user terminal, retransmit the information of oneself in the 3rd subframe.
The difference fed back using the SDF consultations of base station end feedback information according to base station end carries out different processing：If
Decoding is correct mutually for two collaboration users, and they send buddy information in the 3rd time slot；If user's decoding is correct, another
Individual decoding error, the former can send buddy information in the 3rd time slot, but the latter can keep silent；If two with decoding per family
Mistake, to better profit from channel width, base station will notify two users to retransmit the information of oneself by feedback channel, the feedback
Information can be realized by a bit.Above-mentioned new SDF agreements, when channel is poor between user, will not bring performance for cooperation
Loss, because when dual-purpose decoding failure per family, base station can notify two users to retransmit the information of oneself respectively.
Preferably, above-mentioned equivalent channel model can include：Virtual MIMO system.
The corresponding equivalent channel model of different trunk protocols can be otherwise varied, but most cooperative diversity systems can
Virtual mimo system is equivalent to, therefore when from channel model, preferentially from virtual MIMO system.
Preferably, beamforming block 88 may further include：
Diversity condition determining unit, for trunk protocol be above-mentioned utilization base station feedback information SDF agreements when, according to
Subscriber channel condition determines collaboration diversity condition；
Cost function determining unit, the cost function for obtaining beam forming according to MMSE criterions；
Optimal wiener solution determining unit, for obtaining the optimal wiener solution of beam forming weight according to cost function；
Beam shaping elements, for the collaboration diversity condition according to determination, the optimal wiener solution of beam forming weight and final
Reception and send signal complete user terminal cooperative diversity system beam forming.
When using the above-mentioned SDF agreements by the use of base station feedback information as trunk protocol, corresponding collaboration diversity condition
It is not just that uniquely, when carrying out cooperative diversity system beam forming, diversity condition determining unit first has to determine accordingly
Collaboration diversity condition.Then cost function is obtained by cost function determining unit again, optimal wiener solution determining unit generation is optimal
Wiener solution, finally completes cooperative diversity system beam forming by beam shaping elements.
Preferably, above-mentioned collaboration diversity condition can be one below：
Decoding is correct mutually for first user terminal and second user end, and in the 3rd subframe, the first user terminal sends x2, second uses
Family end sends x1, now,
First user terminal decodes correct but second user end decoding error, and in the 3rd subframe, the first user terminal sends x2, the
Two user terminals keep silent；
Second user end decodes correct but the first user terminal decoding error, and in the 3rd subframe, second user end sends x1, the
One user terminal keeps silent；
The equal decoding failure of first user terminal and second user end, in the 3rd subframe, the first user terminal and second user end point
The information x of oneself is not retransmitted1And x2, now,
Wherein, x1The signal sent for the first user terminal in the first subframe nth symbol interval, x2For second user end
The signal sent in the second subframe nth symbol interval,WithIt is that the first user terminal and second user end are divided in the 3rd subframe
The estimate for the buddy information not sent.
This preferred embodiment gives a kind of preferably collaboration diversity condition, cover it is all it can happen that.
As can be seen from the above description, the present invention realizes following technique effect：
(1) under different trunk protocols, diversity gain and BER performances and the close phase of channel quality between user of user
Close, between high user under signal to noise ratio, the total diversity exponent number that user obtains during cooperation is quadravalence；
(2) each user can use any modulation system, it is adaptable to the need for different rates information transfer, and be adaptive
Modulation is provided may；
(3) base station can configure two or many antennas, therefore can provide reception diversity simultaneously, can also be used in base station end
The multi-antenna signal processing technology such as beam forming；
(4) new TDMA mechanism can be using various trunk protocols such as AF and DF and its deformations；
(5) it is significant to improve systematic function using the SDF agreements of base station end feedback information；
(6) new cooperative diversity system beam-forming method is overcome using improved trunk protocol or power distribution mechanism
Between poor user channel strip come influence, when channel is poor between user, cooperation do not bring performance to be lost because when it is dual-purpose per family
During decoding failure, base station can notify two users to retransmit the information of oneself respectively.
Obviously, those skilled in the art should be understood that above-mentioned each module of the invention or each step can be with general
Computing device realize that they can be concentrated on single computing device, or be distributed in multiple computing devices and constituted
Network on, alternatively, the program code that they can be can perform with computing device be realized, it is thus possible to they are stored
Performed in the storage device by computing device, and in some cases, can be shown to be performed different from order herein
The step of going out or describe, they are either fabricated to each integrated circuit modules respectively or by multiple modules in them or
Step is fabricated to single integrated circuit module to realize.So, the present invention is not restricted to any specific hardware and software combination.
The preferred embodiments of the present invention are the foregoing is only, are not intended to limit the invention, for the skill of this area
For art personnel, the present invention can have various modifications and variations.Within the spirit and principles of the invention, that is made any repaiies
Change, equivalent substitution, improvement etc., should be included in the scope of the protection.
Claims (10)
1. a kind of cooperative diversity system beamforming method, it is characterised in that including：
One time division multiple acess TDMA frame is divided into three subframes, the shared subframe of two user terminals carries out information transfer；
The signal that three subframes of one TDMA frame are received and sent is determined according to trunk protocol；
The combined signal received according to equivalent channel model to three subframes carries out the final reception of processing determination and hair
The number of delivering letters；
The cooperative diversity system beam forming of user terminal is completed according to the final reception and transmission signal.
2. according to the method described in claim 1, it is characterised in that the trunk protocol includes at least one of：Amplification is simultaneously
AF agreements are forwarded, decodes and forwards DF agreements, select to decode and forward SDF agreements, the SDF agreements using base station feedback information,
Wherein, the SDF agreements of the utilization base station feedback information include：If decoding is correct mutually at two collaboration user ends,
Buddy information is sent in 3rd subframe mutually；If a user terminal decoding is correct, another decoding error is then decoded correct
User terminal sends buddy information in the 3rd subframe, and the user terminal of decoding error keeps silent；If two user terminals are decoded
Mistake, then retransmit the information of oneself in the 3rd subframe.
3. according to the method described in claim 1, it is characterised in that the equivalent channel model includes：Virtual MIMO
Mimo system.
4. method according to claim 2, it is characterised in that when the trunk protocol is the utilization base station feedback information
SDF agreements when, according to the final reception and send signal complete user terminal cooperative diversity system beam forming include：
Collaboration diversity condition is determined according to subscriber channel condition；
The cost function of beam forming is obtained according to Minimum Mean Square Error MMSE criterions；
The optimal wiener solution of beam forming weight is obtained according to the cost function；
According to the collaboration diversity condition of determination, the optimal wiener solution of the beam forming weight and the final reception and transmission letter
Number complete user terminal cooperative diversity system beam forming.
5. method according to claim 4, it is characterised in that the collaboration diversity condition includes one below：
Decoding is correct mutually for first user terminal and second user end, and in the 3rd subframe, first user terminal sends x2, described
Two user terminals send x1, now,
First user terminal decodes correct but second user end decoding error, in the 3rd subframe, first user terminal
Send x2, the second user end keeps silent；
The second user end decodes correct but described first user terminal decoding error, in the 3rd subframe, the second user end
Send x1, the first user terminal holding silence；
First user terminal and the equal decoding failure in second user end, in the 3rd subframe, first user terminal and described
The information x of oneself is retransmitted at second user end respectively1And x2, now,
Wherein, x1The signal sent for first user terminal in the first subframe nth symbol interval, x2Used for described second
The signal that family end is sent in the second subframe nth symbol interval,WithFor first user terminal and the second user end
The estimate of the buddy information sent respectively in the 3rd subframe, n is positive integer.
6. a kind of cooperative diversity system beam forming device, it is characterised in that including：
Sub-frame division module, for a time division multiple acess TDMA frame to be divided into three subframes, makes two user terminals shared one
Subframe carries out information transfer；
Signal determining module, for determining the signal that three subframes of a TDMA frame are received and sent according to trunk protocol；
Combined Treatment module, the combined signal for being received according to equivalent channel model to three subframes handle really
Fixed final reception and transmission signal；
Beamforming block, the cooperative diversity system wave beam for completing user terminal according to the final reception and transmission signal
Shaping.
7. device according to claim 6, it is characterised in that the trunk protocol includes at least one of：Amplification is simultaneously
AF agreements are forwarded, decodes and forwards DF agreements, select to decode and forward SDF agreements, the SDF agreements using base station feedback information,
Wherein, the SDF agreements of the utilization base station feedback information include：If decoding is correct mutually at two collaboration user ends,
Buddy information is sent in 3rd subframe mutually；If a user terminal decoding is correct, another decoding error is then decoded correct
User terminal sends buddy information in the 3rd subframe, and the user terminal of decoding error keeps silent；If two user terminals are decoded
Mistake, then retransmit the information of oneself in the 3rd subframe.
8. device according to claim 6, it is characterised in that the equivalent channel model includes：Virtual MIMO
Mimo system.
9. device according to claim 7, it is characterised in that the beamforming block includes：
Diversity condition determining unit, for the trunk protocol be the utilization base station feedback information SDF agreements when, according to
Subscriber channel condition determines collaboration diversity condition；
Cost function determining unit, the cost function for obtaining beam forming according to Minimum Mean Square Error MMSE criterions；
Optimal wiener solution determining unit, for obtaining the optimal wiener solution of beam forming weight according to the cost function；
Beam shaping elements, for the collaboration diversity condition according to determination, the optimal wiener solution of the beam forming weight and described
Final reception and transmission signal completes the cooperative diversity system beam forming of user terminal.
10. device according to claim 9, it is characterised in that the collaboration diversity condition includes one below：
Decoding is correct mutually for first user terminal and second user end, and in the 3rd subframe, first user terminal sends x2, described
Two user terminals send x1, now,
First user terminal decodes correct but second user end decoding error, in the 3rd subframe, first user terminal
Send x2, the second user end keeps silent；
The second user end decodes correct but described first user terminal decoding error, in the 3rd subframe, the second user end
Send x1, the first user terminal holding silence；
First user terminal and the equal decoding failure in second user end, in the 3rd subframe, first user terminal and described
The information x of oneself is retransmitted at second user end respectively1And x2, now,
Wherein, x1The signal sent for first user terminal in the first subframe nth symbol interval, x2Used for described second
The signal that family end is sent in the second subframe nth symbol interval,WithFor first user terminal and the second user end
The estimate of the buddy information sent respectively in the 3rd subframe, n is positive integer.
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| CN101527969A (en) * | 2008-03-04 | 2009-09-09 | 中兴通讯股份有限公司 | Information interaction method |
| CN101860386A (en) * | 2009-04-13 | 2010-10-13 | 中兴通讯股份有限公司 | Multi-user random beam forming method and system |
| CN101909299A (en) * | 2009-06-05 | 2010-12-08 | 中兴通讯股份有限公司 | Processing method of collaborated multi-input multi-output and relay station |
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| CN101860386A (en) * | 2009-04-13 | 2010-10-13 | 中兴通讯股份有限公司 | Multi-user random beam forming method and system |
| CN101909299A (en) * | 2009-06-05 | 2010-12-08 | 中兴通讯股份有限公司 | Processing method of collaborated multi-input multi-output and relay station |
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