CN101662319A - Closed loop macro diversity method based on disturbance theory in coordinated multi-point system - Google Patents

Abstract

The invention relates to the field of wireless communication and discloses a closed loop macro diversity method based on the disturbance theory in a coordinated multi-point (CoMP) system. The closed loop macro diversity method comprises the following steps: a plurality of base stations serve one user together; under the condition that the channel information and the data information are completelyshared, each base station respectively carries out the design of precoding, and then, a base station controller is used for adjusting the phase position of the precoding vector; and the higher received signal combining gain is obtained by adjusting the phase position of each row of the right singularity matrix of the channel. The channel state information (CSI) can be obtained by up-link feedback(FDD system) or direct channel estimation (TDD system). Compared with the prior art, the invention has higher frequency spectrum efficiency and better interruption probability performance and can notincrease the extra feedback cost and the data sharing cost.

Description

In the Synergistic multi-point system based on the closed loop macro diversity method of disturbance theory

Technical field

The present invention relates to wireless communication field, particularly based on the communication technology of the closed loop macro diversity of disturbance theory.

Background technology

Along with increasing rapidly of wireless communication needs, effectively utilize frequency spectrum resource to become and become more and more important.At present, mobile communication system adopts cellular wireless system to effectively utilize limited frequency spectrum resources.Multiple-input and multiple-output (MIMO) communication technology attains full development in recent years.It is to utilize space resources to realize a kind of effective means of high-rate link transmission, can under the situation that does not increase extra spectrum and power, significantly increase the transmission rate and the reliability of communication system, be acknowledged as one of key technology in the next generation mobile communication.Defeated (MIMO) Study on Technology of point-to-point multi-antenna transmitting reaches its maturity, and it can improve the validity of spectrum efficiency, link reliability and power utilization effectively by spatial reuse gain, diversity gain and array gain.Yet along with the raising to communicating requirement, as two-forty, high quality-of-service (QoS) requirement, high coverage rate etc., traditional MIMO technique table reveals many defectives, and for example: the sub-district coverage rate is narrow, has coverage hole or blind spot; Because the bad channel conditions of near-far interference and Cell Edge User makes transmission rate not high; Under the crowded situation in sub-district, the adjacent cell flow of balance is difficulty relatively, and all are the center with the base station, base station complexity height; Strong to the base station dependence, limited by number of antennas, user diversity degree low (SER and QoS are affected) etc.Downlink multipoint cooperation (CoMP) transmission can effectively be lowered presence of intercell interference (ICI), improves the two-forty covering, promotes the Cell Edge User throughput and be improved throughput of system.According to the demand of customer traffic, the CoMP scheme can be divided into two big classes: Combined Treatment (JP) and collaborative process scheduling/cooperative beam form (CS/CB), and wherein a technology of Combined Treatment (JP) scheme is joint transmission (JT) technology.The basic principle of joint transmission technology is, a plurality of base stations send data to a user simultaneously, thereby improves user's received signal quality or eliminate other users' interference, and under this scheme, the data that the user need receive come from different base stations.Receiving terminal (being user side), utilize relevant merging or incoherent merging will handle to received signal.This advanced technology can obviously improve the Cell Edge User throughput to the Cell Edge User advantageous particularly.Under the situation at base station shared data information and complete channel information, existing single user's multipoint cooperative (SU-CoMP) precoding technique has been proposed a kind of improvement project, promptly the pre-coding matrix phase adjusting method further promotes the cooperation transmission performance.

Summary of the invention

Technical problem: the technical problem underlying that each execution mode of the present invention will solve provides in a kind of coordinate multipoint (CoMP) system based on the closed loop macro diversity method of disturbance theory, and the many base station systems that make distributed collaborative handle obtain gratifying performance for wireless communications.

Technical scheme: the closed loop macro diversity method based on disturbance theory in the Synergistic multi-point system may further comprise the steps:

A. the coordinate multipoint communication system is that base station transmitting terminal, a base station controller are that base stations control end and a mobile subscriber are that user's receiving terminal is formed by two cooperative base station,

B. Xie Zuo two same users of base station services obtain downlink channel information CSI respectively, obtain pre-coding matrix separately, and feed back to base station controller;

C. base station controller is according to the feedback information of two cooperative base station, and one group of pre-coding matrix is wherein carried out the column vector adjustment, obtains higher signal combination gain;

D. base station controller calculates a precoding column vector adjustment diagonal matrix according to pre-coding matrix and maximization in conjunction with the principle that gains, and promptly produces a perturbation matrix, and this diagonal matrix is sent to corresponding base station;

E. after the base station transmitting terminal received corresponding pre-coding matrix and precoding column vector adjustment matrix respectively, after process precoding and precoding vector were adjusted before sending, the base station transmitting terminal sent to same user with same data message;

F. user's receiving terminal receives same data message from two cooperative base station, because handle through base station transmitting terminal precoding and precoding vector adjustment before sending, user's receiving end signal is strengthened, and receives Signal to Interference plus Noise Ratio and improves, and the mobile subscriber obtains very high macro diversity.

Described base station transmitting terminal only need change very slow channel information, according to channel information calculating pre-coding matrix separately, calculates the precoding column vector simultaneously and adjusts diagonal matrix;

Described user's receiving terminal can carry out channel estimating to whole channel and obtain channel response, and the downlink channel information CSI that obtains is fed back to cooperative base station.

Two cooperative base station are according to the local channel information calculations pre-coding matrix of institute's service-user, W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix, then with W ₁And W ₂Feed back to base station controller.

Described base station controller obtains higher received signal in conjunction with gain, that is: by the phase place of adjusting right each row of singular value matrix after receiving the feedback information of each base station

${\underset{D}{\arg \max }\left|\right|H_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_1+H_2{W}_{2}D\left|\right|}_{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">F</figure-callout>}}^2$

Wherein

Expression makes the value of matrix D when satisfying expression formula in the bracket; Max () expression makes expression formula maximum in the bracket; || | _|F ²Representing matrix Frobenius norm square.D is the diagonal matrix of R*R, and diagonal element is

, R depends on the columns of W2, i.e. the data fluxion of each base station transmission.By search method, can (r=1,2 ..., R) selection obtains maximized

, that is:

Be applicable to the base station of any a plurality of participation cooperations and the θ of arbitrary accuracy _rAngle, this depends on the compromise between computation complexity and the performance.

Described user's receiving end signal is expressed as:

$r=\sqrt{P_1}{H}_1{W}_{1}x+\sqrt{P_2}{H}_2{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\mathrm{Dx}+n$

P wherein ₁, P ₂Be respectively that the user is from the base station 1 and the received power of base station 2; W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix; N is additive white Gaussian noise (AWGN).The channel matrix of equivalence can be expressed as

Channel condition information (CSI) can estimate that (TDD system) obtains by uplink feedback (FDD system) or by direct channels.Under above-mentioned collaborative process, the user receives Signal to Interference plus Noise Ratio (SINR) and can be expressed as:

$\mathrm{SINR}=\frac{{\left|\right|H_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\left|\right|}^2{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_1+{\left|\right|H_1{W}_{2}D\left|\right|}^2{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}$

σ wherein _o ²Be additive white Gaussian noise power.

Beneficial effect: channel condition information (CSI) can estimate that (TDD system) obtains by uplink feedback (FDD system) or by direct channels.The present invention compared with prior art has higher spectrum efficiency and better outage probability performance, and does not increase extra feedback overhead and data sharing expense.

Description of drawings

Fig. 1 is a system model,

Fig. 2 be the total speed of user with signal to noise ratio conversion curve figure,

User's cumulative distribution function (CDF) was along with the curve chart of the total rate variation of system when Fig. 3 was a signal to noise ratio snr=0dB,

Fig. 4 is signal to noise ratio snr=0dB, and user's cumulative distribution function (CDF) is along with the curve chart of the total rate variation of system during 50% outage probability.

Embodiment

Embodiments of the present invention disclose in a kind of coordinate multipoint (CoMP) system based on the closed loop macro diversity method of disturbance theory, comprise following steps:

User's communications scene of a plurality of base stations common service, promptly " closed loop macro diversity (Closed-Loop MacroDiversity, CL-MD) ".Under the situation that channel information and data message are shared fully, each base station is according to the local channel information calculations pre-coding matrix of institute's service-user, i.e. W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix.Then with W ₁And W ₂Feed back to base station controller.

Described base station controller obtains higher received signal in conjunction with gain by the phase place of adjusting right each row of singular value matrix after receiving the feedback information of each base station.Promptly

${\underset{D}{\arg \max }\left|\right|H_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_1+H_2{W}_{2}D\left|\right|}_{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">F</figure-callout>}}^2$

Wherein

Expression makes the value of matrix D when satisfying expression formula in the bracket; Max () expression makes expression formula maximum in the bracket; || || _F ²Representing matrix Frobenius norm square.D is the diagonal matrix of R*R, and diagonal element is

, R depends on the columns of W2, i.e. the data fluxion of each base station transmission.By search method, can

(r=1,2 ..., R) selection obtains maximized

, that is:

Be applicable to the base station of any a plurality of participation cooperations and the θ of arbitrary accuracy _rAngle, this depends on the compromise between computation complexity and the performance.

Described receiving end signal can be expressed as:

$r=\sqrt{P_1}{H}_1{W}_{1}x+\sqrt{P_2}{H}_2{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\mathrm{Dx}+n$

P wherein ₁, P ₂Be respectively that the user is from the base station 1 and the received power of base station 2; W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix; N is additive white Gaussian noise (AWGN).The channel matrix of equivalence can be expressed as Under above-mentioned collaborative process, the user receives Signal to Interference plus Noise Ratio (SINR) and can be expressed as:

$\mathrm{SINR}=\frac{{\left|\right|H_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\left|\right|}^2{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_1+{\left|\right|H_1{W}_{2}D\left|\right|}^2{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}$

σ wherein _o ²Be additive white Gaussian noise power.

1. coordinate multipoint (CoMP) communication system is made up of two cooperative base station and mobile subscriber's receiving terminal.

2. cooperative base station estimates that by uplink feedback (FDD system) or by direct channels (TDD system) obtains channel condition information (CSI), and this channel information and data message are shared by base station controller in two base stations of cooperation.

3. base station controller calculates a precoding column vector adjustment diagonal matrix according to the channel information of two base stations, and the computational methods of this diagonal matrix are:

${\underset{D}{\arg \max }\left|\right|H_1{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A2009100353840010H1.png"\; state="\{\{state\}\}">W</figure-callout>}}_1+H_2{W}_{2}D\left|\right|}_{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A2009100353840009H1.png"\; state="\{\{state\}\}">F</figure-callout>}}^2$

Wherein

Expression makes the value of matrix D when satisfying expression formula in the bracket; Max () expression makes expression formula maximum in the bracket; || || _F ²Square (same under the usage of above-mentioned three symbols) of representing matrix Frobenius norm.The pre-coding matrix W of base station controller difference known base station 1 and base station 2 ₁, W ₂With corresponding to channel matrix H ₁And H ₂D is the diagonal matrix of R*R, and diagonal element is

, R depends on the columns of W2, i.e. the data fluxion of each base station transmission.By search method, can (r=1,2 ..., R) selection obtains maximized , that is:

Be applicable to the base station of any a plurality of participation cooperations and the θ of arbitrary accuracy _rAngle, this depends on the compromise between computation complexity and the performance.

4. cooperative base station is according to the pre-coding matrix of base station controller distribution, and the precoding column vector is adjusted diagonal matrix and user's data information, mails to the mobile subscriber synchronously.

5. the mobile subscriber receives the data message that two cooperative base station send, and carries out signal and merges, and obtains the higher Signal to Interference plus Noise Ratio of accepting.

Claims (5)

1. In the Synergistic multi-point system based on the closed loop macro diversity method of disturbance theory, it is characterized in that this method may further comprise the steps:

   A. the coordinate multipoint communication system is that base station transmitting terminal, a base station controller are that base stations control end and a mobile subscriber are that user's receiving terminal is formed by two cooperative base station,

   B. Xie Zuo two same users of base station services obtain downlink channel information CSI respectively, obtain pre-coding matrix separately, and feed back to base station controller;

   C. base station controller is according to the feedback information of two cooperative base station, and one group of pre-coding matrix is wherein carried out the column vector adjustment, obtains higher signal combination gain;

   D. base station controller calculates a precoding column vector adjustment diagonal matrix according to pre-coding matrix and maximization in conjunction with the principle that gains, and promptly produces a perturbation matrix, and this diagonal matrix is sent to corresponding base station;

   E. after the base station transmitting terminal received corresponding pre-coding matrix and precoding column vector adjustment matrix respectively, after process precoding and precoding vector were adjusted before sending, the base station transmitting terminal sent to same user with same data message;

   F. user's receiving terminal receives same data message from two cooperative base station, because handle through base station transmitting terminal precoding and precoding vector adjustment before sending, user's receiving end signal is strengthened, and receives Signal to Interference plus Noise Ratio and improves, and the mobile subscriber obtains very high macro diversity.
2. 2. based on the closed loop macro diversity method of disturbance theory, it is characterized in that in the Synergistic multi-point system according to claim 1,

   Described base station transmitting terminal only need change very slow channel information, according to channel information calculating pre-coding matrix separately, calculates the precoding column vector simultaneously and adjusts diagonal matrix;

   Described user's receiving terminal can carry out channel estimating to whole channel and obtain channel response, and the downlink channel information CSI that obtains is fed back to cooperative base station.
3. 3. based on the closed loop macro diversity method of disturbance theory, it is characterized in that in the Synergistic multi-point system according to claim 1,

   Two cooperative base station are according to the local channel information calculations pre-coding matrix of institute's service-user, W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix, then with W ₁And W ₂Feed back to base station controller.
4. 4. based on the closed loop macro diversity method of disturbance theory, it is characterized in that in the Synergistic multi-point system according to claim 1,

   Described base station controller obtains higher received signal in conjunction with gain, that is: by the phase place of adjusting right each row of singular value matrix after receiving the feedback information of each base station

   $\underset{D}{\arg \max }{\left|\right|H_1{W}_1+H_2{W}_{2}D\left|\right|}_F^2$

   Wherein

   

   Expression makes the value of matrix D when satisfying expression formula in the bracket; Max () expression makes expression formula maximum in the bracket; || || _F ²Representing matrix Frobenius norm square; D is the diagonal matrix of R*R, and diagonal element is

   

   R depends on the columns of W2, i.e. the data fluxion that sends of each base station, by search method, can

   

   (r=1,2 ..., R) selection obtains maximized

   

   That is:

   

   Be applicable to the base station of any a plurality of participation cooperations and the θ of arbitrary accuracy _rAngle, this depends on the compromise between computation complexity and the performance.
5. 5. based on the closed loop macro diversity method of disturbance theory, it is characterized in that in the Synergistic multi-point system according to claim 1,

   Described user's receiving end signal is expressed as:

   $r=\sqrt{P_1}{H}_1{W}_{1}x+\sqrt{P_2}{H}_2{W}_2\mathrm{Dx}+n$

   P wherein ₁, P ₂Be respectively that the user is from the base station 1 and the received power of base station 2; W ₁, W ₂Be respectively the pre-coding matrix of base station 1 and base station 2, corresponding to channel matrix H ₁And H ₂Right singular value matrix; N is additive white Gaussian noise AWGN; The channel matrix of equivalence can be expressed as Channel condition information CSI can estimate that the TDD system obtains by uplink feedback FDD system or by direct channels, and under above-mentioned collaborative process, the user receives Signal to Interference plus Noise Ratio SINR and is expressed as:

   $\mathrm{SINR}=\frac{{\left|\right|H_1{W}_1\left|\right|}^2{P}_1+{\left|\right|H_1{W}_{2}D\left|\right|}^2{P}_2}{{\mathrm{\&sigma;}}_o^2}$

   σ wherein _o ²Be additive white Gaussian noise power.

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