CN202435416U - Multiple-input multiple-output self-adaption mode switching device - Google Patents

Abstract

The utility model discloses a multiple-input multiple-output self-adaption mode switching device. The multiple-input multiple-output self-adaption mode switching device is a multiple-input multiple-output self-adaption switching mode based on the combination of relevance and signal interference noise ratio, a sending mode is determined by conducting capacity comparison at the information channel changing position, when the information channel condition is not changed, the sending mode can be determined by comparing the relevance and the signal interference noise ratio with the relevance and the signal interference noise threshold, so that the complexity of the calculation is lowered effectively, meanwhile, a feasible and effective threshold determining mechanism is provided, the sending mode can be adjusted according to different information channel conditions so as to be suitable for the current information channel state, the optimal MIMO (multiple-input multiple-output) sending mode can be selected in a self-adaption manner, the system capability is improved, meanwhile, the reliability is ensured, and the performance of the MIMO system is optimal.

Description

A kind of multiple input multiple output adaptive mode-changeover device

Technical field

The utility model relates to multiple-input and multiple-output (MIMO:Multiple-input Multiple-output) system in the third generation partner program Long Term Evolution (3GPP LTE) in a kind of wireless communication technology, is specifically related to a kind of multiple input multiple output adaptive mode-changeover device based on correlation and Signal to Interference plus Noise Ratio associating.

Background technology

Multiple-input and multiple-output (MIMO) technology is the key technology of LTE, and it is to utilize many antennas to suppress the technical scheme of channel fading, can the spatial reuse gain is provided and send diversity gain for system.At present, the employed transmission plan of multi-input multi-output system has: spatial reuse (SM) technology, transmission divide collection (TD) technology, space and time diversity (D-STTD) technology or beam shaping (BF) technology.Yet existing these transmission plans differ from one another at present: 1, space multiplexing technique can improve channel capacity, but has reduced the reliability of system; Though 2, send the reliability that diversity technique has improved channel, be cost with the minimizing capacity; 3, exist compromise between branch collection and the multiplex technique, the space and time diversity technology is that four antennas are equally divided into two antenna sets, and two antennas in the antenna sets adopt the mode of sending the branch collection to send, and adopt the mode of spatial reuse to send between the antenna sets; 4, beam forming technique produces the wave beam with directive property by many antennas, and concentration of energy in the defeated direction of tendency to develop, is increased signal quality, and reduce and other users between interference, but also be that throughput with sacrificial system is a cost.

The utility model content

The utility model technical problem to be solved provides a kind of multiple input multiple output adaptive mode-changeover device; It can make wireless communication system for different channel conditions; Select optimum multiple-input and multiple-output launch scenario adaptively, make mimo system obtain optimum performance.

For addressing the above problem, the utility model is realized through following technical scheme:

A kind of multiple input multiple output adaptive mode-changeover device of the utility model comprises transmitter, transmission antenna group, the receiver that is made up of a plurality of transmitting antennas and the reception antenna group that is made up of a plurality of reception antennas.Wherein,

Said transmitter mainly is made up of modulation and coding module, transmitting terminal mode switch module and sending module; Wherein be provided with spatial reuse sending mode unit, beam shaping sending mode unit and space and time diversity sending mode unit in the sending module; Modulation links to each other with sending module via the transmitting terminal mode switch module with coding module, and sending module connects transmission antenna group.

Said receiver mainly is made up of receiving terminal mode switch module, receiver module, modulation and decoder module, channel estimation module, calculation of capacity module, capacity comparing module, thresholding determination module, thresholding comparing module and feedback module; Wherein the reception antenna group is connected with channel estimation module with mode switch module; The output of mode switch module links to each other with decoder module with demodulation via receiver module; The output connection capacity computing module and the receiver module of channel estimation module; The output of calculation of capacity module is divided into 2 the tunnel, and wherein one the tunnel links to each other with feedback module via the capacity comparing module, and another road then links to each other with feedback module with the thresholding comparing module through the thresholding determination module successively; The output of feedback module is divided into 2 the tunnel, the one tunnel and directly links to each other with the receiving terminal mode switch module, and another road connects the transmitting terminal mode switch module via based on feedback link.

As improvement, the utility model also further includes a channel condition judge module, and the input of this channel condition judge module links to each other with channel estimation module, and its output links to each other with the thresholding comparing module with the calculation of capacity module respectively.

Compared with prior art, the multiple input multiple output adaptive mode switch scheme based on correlation and Signal to Interference plus Noise Ratio associating that the utility model proposes only needs to change part at channel condition and carries out Capacity Ratio to confirming sending mode; And when channel condition does not change; Then can pass through relatively more definite sending mode of correlation and Signal to Interference plus Noise Ratio and correlation and Signal to Interference plus Noise Ratio threshold value, thereby effectively reduce the complexity of calculating, propose effective thresholding simultaneously and confirm mechanism; Can adjust sending mode at any time according to different channel conditions; To adapt to the state of current channel, select optimum MIMO sending mode adaptively, when having improved the capacity of system; Also guaranteed its reliability, it is optimum that the performance of mimo system reaches.

Description of drawings

Fig. 1 is a kind of multiple input multiple output adaptive sending mode changing method flow chart;

Fig. 2 is that sending mode switches sketch map in the thresholding comparison process;

Fig. 3 is a kind of structural representation of multiple input multiple output adaptive sending mode switching device shifter.

Embodiment

Referring to Fig. 1, a kind of multiple input multiple output adaptive mode switching method of the utility model comprises the steps:

(1) receiving-transmitting sides agreement spatial reuse, beam shaping and the numbering of 3 kinds of sending modes of space and time diversity and initial sending mode.

In the utility model preferred embodiment; The sending mode of receiving-transmitting sides agreement comprises spatial reuse (SM) sending mode, space and time diversity (D-STTD) sending mode and beam shaping (BF) sending mode; Wherein SM is 1, and BF is 2, and D-STTD is 3; And the value of MIMO pattern indication (MMI) is set by above-mentioned numbering, MMI is fed back to transmitter through uplink physical channel.The MMI that transmitter comes according to the receiver feedback selects corresponding sending mode.In addition, be without loss of generality, suppose that the initialization pattern of receiving-transmitting sides agreement is SM, i.e. MMI=1.

(2) receiver estimates to obtain current channel information to current channel, and calculates current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR according to current channel information.

In the utility model preferred embodiment, obtain the unbiased estimator H of channel matrix according to channel estimation module.Wherein,

1. the calculating of correlation ρ:

The estimated channel matrix is carried out Kronecker decompose,

$H=R^{\frac{1}{2}}{\mathrm{ZS}}^{\frac{1}{2}}$

Wherein,

is the Gauss of the independent distribution at random matrix of zero-mean, unit covariance; for receiving correlation matrix,

is for sending correlation matrix.

Then the correlation of indices model of transmitting terminal and receiving terminal is respectively

$R_{i,j}={\mathrm{\ρ}}_{\mathrm{rX}}^{|i-j|},$ $S_{i,j}={\mathrm{\ρ}}_{\mathrm{tX}}^{|i-j|}$

Wherein, ρ _RXAnd ρ _TXBe respectively the reception between the adjacent antennas and send space correlation coefficient.

2. the calculating of Signal to Interference plus Noise Ratio SINR:

A. as if the current SM sending mode that is in of system, then when the Signal to Interference plus Noise Ratio SINR of the multiplexing sending mode of computer memory, 2 * 2 mimo system can be divided into two 1 * 2 SIMO subsystem under the ideal communication channel condition.So that each individual subsystem SIMO channel coefficient and

are each independently SIMO equivalent signal to interference noise ratio

is the power spectral density of receiving terminal noise

So, be generalized to N _tThe SINR of the SM scheme of individual transmitting antenna does

${\mathrm{SINR}}_{\mathrm{SM}}=2^{\frac{\underset{i=1}{\overset{N_t}{\mathrm{\Σ}}}\mathrm{lo}{g}_2(1+{\mathrm{SINR}}_{\mathrm{SM},i})}{N_t}}-1$

B. if the current D-STTD sending mode that is in of system in order to reduce by two interference between the antenna sets, can use optimum organization (Optimum Combining, technology OC) at receiving terminal.The OC of k data flow detects vector

$W_k={(B_k+\frac{1}{p}{I}_{{2N}_r})}^{-1}{h}_k$

Wherein, ρ=E _s/ N ₀Be the signal to noise ratio of single data stream,

Be unit matrix, B _kBe interference covariance matrix, and following expression is arranged

$B_k=\left\{\begin{array}{c}{h}_3{h}_3^H+h_4{h}_4^H,k=\mathrm{1,2}\\ h_1{h}_1^H\text{+}{h}_2{h}_2^H,k=\mathrm{3,4}\end{array}\right.$

The computing formula of the SINR of k data flow does

${\mathrm{SINR}}_{D-\mathrm{STTD},k}=\frac{{\left|w_k^H{h}_k\right|}^2}{w_k^H(B_k+\frac{1}{p}{I}_{{2N}_r})w_k}$

And because

So

which can be obtained D-STTD scheme of the SINR k data streams of

${\mathrm{SINR}}_{D-\mathrm{STTD},k}=h_k^H{(B_k+\frac{1}{p}{I}_{{2N}_r})}^{-1}{h}_k$

C. for the BF sending mode that uses the high specific combination receiver, the full-diversity gain can be provided.Consider N _tIndividual transmitting antenna N _rIndividual reception antenna has the wireless transmitting system of an additive white Gaussian noise and L common-channel interference, supposes that interference channel is the flat fading Rayleigh channel.Then the reception vector of receiving terminal does

$r=\sqrt{P_2}{H}_0{w}_T{x}_0+H_I{P}_I^{\frac{1}{2}}{x}_I+n$

x ₀Be the useful signal that will send, x _IBe the interference signal vector, and x is arranged _I=[x ₁, x ₂..., x _L] ^TP ₀Be the average power of receiving terminal desired signal, P _IBe the receiving terminal interfering signal power, and P is arranged _I=diag{P ₁, P ₂... P _L.H ₀N for the desired signal process _r* N _tChannel matrix, H _IBe L N that disturbs _rThe channel matrix of * L, n are additive white Gaussian noise.w _TBeamforming vectors for transmitting terminal.

Use the high specific combination at receiving terminal, make the combined weights vector be w _RFor the maximize signal combination, transmitting terminal uses the high specific transmission, and (Maximum ratio transmission MRT), then has

w _T＝u _max

w _R＝H ₀u _max

u _MaxFor

The unit standard feature vector that eigenvalue of maximum is corresponding.

So the composite signal of receiving terminal does

$z=w_R^H$

$=\sqrt{P_0}{u}_{\max }^H{H}_0^H{H}_0{u}_{\max }{x}_0+u_{\max }^H{H}_0^H{H}_I{P}_I^{\frac{1}{2}}{x}_I+u_{\max }^H{H}_0^{H}n$

Then the SINR of MIMO-MRC system does

${\mathrm{SINR}}_{\mathrm{BF}}=\frac{P_0{\left|\right|u_{\max }^H{H}_0^H{H}_0{u}_{\max }\left|\right|}^2}{u_{\mathrm{mzx}}^H{H}_0^H{H}_I{P}_I{H}_I^H{H}_0{u}_{\max }+{\mathrm{\σ}}_n^2{\left|\right|u_{\max }^H{H}_0^H\left|\right|}^2}$

Because u _MaxFor The unit standard feature vector that eigenvalue of maximum is corresponding, so ${\left|\right|u_{\mathrm{Max}}^H{H}_0^H{H}_0{u}_{\mathrm{Max}}\left|\right|}^2={\mathrm{\λ}}_{\mathrm{Max}}^2,$ ${\left|\right|u_{\mathrm{Max}}^H{H}_0^H\left|\right|}^2={\mathrm{\λ}}_{\mathrm{Max}},$ So

${\mathrm{SINR}}_{\mathrm{BF}}=\frac{{\mathrm{\Ω}}_0{\mathrm{\λ}}_{\max }}{\underset{i=1}{\overset{L}{\mathrm{\Σ}}}\frac{{\mathrm{\Ω}}_i{\left|\right|u_{\max }^H{H}_0^H{H}_{I,i}\left|\right|}^2}{{\mathrm{\λ}}_{\max }}}$

Wherein

Be the average SNR that receives,

Be the average interference noise ratio (INR) that receives, H _{I, i}Be matrix H _II row.

(3) receiver calculates the capacity of the following 3 kinds of sending modes of current channel condition according to current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR.

1. for the sending mode of SM, the capacity of system does

$C_{\mathrm{SM}}=\mathrm{\ϵ}\left\{\underset{k=1}{\overset{N_t}{\mathrm{\Σ}}}\mathrm{lo}{g}_2(1+r_k)\right\}$

γ wherein _kBe the Signal to Interference plus Noise Ratio of k data flow, use when compeling zero (zero-forcing) receiver its probability density function f (γ _k) be function about channel relevancy.

2. for the BF sending mode that uses the high specific combination receiver, its traversal capacity does

$C_{\mathrm{BF}}=-\frac{1}{1n2}\underset{i-1}{\overset{N_r}{\mathrm{\Σ}}}(\underset{j=1,j\≠i}{\overset{N_r}{\mathrm{\Π}}}\left(\frac{{\mathrm{\λ}}_{r,i}}{{\mathrm{\λ}}_{r,i}-{\mathrm{\λ}}_{r,j}}\right)\exp \left(\frac{1}{r_0{\mathrm{\λ}}_{s,\max }{\mathrm{\λ}}_{r,i}}\right)\mathrm{Ei}(-\frac{1}{r_0{\mathrm{\λ}}_{s,\max }{\mathrm{\λ}}_{r,i}})$

Wherein, γ ₀Be Signal to Interference plus Noise Ratio, λ _{S, max}For sending the eigenvalue of maximum of correlation matrix S, λ _{R, i}And λ _{R, j}Be respectively i and j characteristic value receiving correlation matrix R.

3. use the capacity formula of the D-STTD sending mode of linear receiver can be expressed as

$C_{D-\mathrm{STTD}}={\mathrm{\ϵ}}_{r_k}\left[\frac{1}{2}\underset{k=1}{\overset{N_t}{\mathrm{\Σ}}}{\log }_2(1+r_k)\right]$

γ wherein _kIt is the Signal to Interference plus Noise Ratio of k data flow.In the sending mode of D-STTD, there is γ ₁=γ ₂, γ ₃=γ ₄, and γ _k(k=1 ..., 4) be unified the distribution.So can simplify to following formula

C _D-STTD＝2ε _γ[log ₂(1+γ)]

The comparison of typical case's sending mode capacity: under same channel condition, calculate the capacity of three kinds of typical sending modes.Work as C _SM>=C _BFAnd C _SM>=C _D-STTDThe time, select the SM sending mode; Work as C _BF>=C _SMAnd C _BF>=C _D-STTDThe time, select the BF sending mode; Work as C _D-STTD>=C _SMAnd C _D-STTD>=C _BFThe time, select the D-STTD sending mode.

(4) receiver compares the capacity of above-mentioned 3 kinds of sending modes, and the maximum sending mode of the capacity of choosing feeds back to transmitter as the initial optimum sending mode under this channel condition.

(5) the initial optimum sending mode that feeds back to according to receiver of transmitter becomes initial optimum sending mode with the sending mode of transmitter.

(6) afterwards, receiver obtains the correlation threshold value ρ under the current channel condition through the contrast or the field testing of capacity _ThWith Signal to Interference plus Noise Ratio threshold value SINR _Th

In the utility model preferred embodiment, the threshold value ρ of correlation _ThThreshold value SINR with Signal to Interference plus Noise Ratio _ThDefinite method following:

Receiver is with T coherence time under the current channel condition _cBe made as thresholding and confirm the cycle, promptly every at a distance from T coherence time _cConfirm the threshold value ρ of a correlation _ThThreshold value SINR with Signal to Interference plus Noise Ratio _Th,

Threshold value ρ in correlation _ThThreshold value SINR with Signal to Interference plus Noise Ratio _ThDefinite process in, when channel condition changes, need to confirm again the threshold value ρ of correlation _ThThreshold value SINR with Signal to Interference plus Noise Ratio _ThOtherwise, do not confirm the threshold value ρ of correlation again _ThThreshold value SINR with Signal to Interference plus Noise Ratio _Th

(7) receiver is every at a distance from T coherence time _cJust with current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR respectively with correlation threshold value ρ _ThWith Signal to Interference plus Noise Ratio threshold value SINR _ThCompare, as shown in Figure 2,

As ρ≤ρ _ThAnd SINR≤SINR _ThThe time, select the space and time diversity sending mode as the optimum sending mode in this coherence time;

As ρ≤ρ _ThAnd SINR>=SINR _ThThe time, select the spatial reuse sending mode as the optimum sending mode in this coherence time;

As ρ>=ρ _ThAnd SINR≤SINR _ThThe time, select the beam shaping sending mode as the optimum sending mode in this coherence time;

As ρ>=ρ _ThAnd SINR>=SINR _ThThe time, then need compare capacity under beam shaping sending mode and the spatial reuse sending mode and decide and select capacity is bigger in beam shaping sending mode or the spatial reuse sending mode sending mode as the optimum sending mode in this coherence time.

(8) the optimum sending mode of transmitter in this coherence time of feeding back to according to receiver becomes the optimum sending mode in this coherence time with the sending mode of transmitter next coherence time.

In order to reduce the complexity of calculating; The utility model can each sending mode of double counting when channel condition is constant capacity, and can compare the sending mode that judgement should be adopted according to the value of current correlation and Signal to Interference plus Noise Ratio and the threshold value of correlation and Signal to Interference plus Noise Ratio.The threshold value ρ of correlation _ThThreshold value SINR with Signal to Interference plus Noise Ratio _ThPromptly can compare and obtain, also can come out through field testing through the capacity of 3 kinds of sending modes.Therefore, in step (6) before, also comprise every at a distance from coherence time Tc judge the step whether channel condition of this moment and previous moment changes; If judge when channel condition changes, be back to step (3); If judge when channel condition does not change, then directly carry out step (7).

Referring to Fig. 3, according to a kind of multiple input multiple output adaptive mode-changeover device that said method designed, comprise transmitter, transmission antenna group, the receiver that constitutes by a plurality of transmitting antennas and the reception antenna group that constitutes by a plurality of reception antennas.

Said transmitter mainly is made up of modulation and coding module, transmitting terminal mode switch module and sending module; Wherein be provided with spatial reuse sending mode unit, beam shaping sending mode unit and space and time diversity sending mode unit in the sending module; Modulation links to each other with sending module via the transmitting terminal mode switch module with coding module, and sending module connects transmission antenna group.

Said receiver mainly is made up of receiving terminal mode switch module, receiver module, modulation and decoder module, channel estimation module, calculation of capacity module, capacity comparing module, thresholding determination module, thresholding comparing module and feedback module; Wherein the reception antenna group is connected with channel estimation module with mode switch module; The output of mode switch module links to each other with decoder module with demodulation via receiver module; The output connection capacity computing module and the receiver module of channel estimation module; The output of calculation of capacity module is divided into 2 the tunnel, and wherein one the tunnel links to each other with feedback module via the capacity comparing module, and another road then links to each other with feedback module with the thresholding comparing module through the thresholding determination module successively; The output of feedback module is divided into 2 the tunnel, the one tunnel and directly links to each other with the receiving terminal mode switch module, and another road connects the transmitting terminal mode switch module via based on feedback link.

Transmitting terminal mode switch module and receiving terminal mode switch module are switched the sending mode of sending module and the receiving mode of receiver module respectively.

Channel estimation module is used for current channel is estimated, and calculates current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR according to current channel information.

The calculation of capacity module is used for calculating the capacity of the following 3 kinds of sending modes of current channel condition according to current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR;

The capacity comparing module, the capacity of 3 kinds of sending modes that are used for the calculation of capacity module is calculated compares, and chooses the maximum sending mode of capacity and deliver in the feedback module as the initial optimum sending mode under this channel condition;

The thresholding determination module is used for obtaining the correlation threshold value ρ under the current channel condition through the contrast or the field testing of capacity _ThWith Signal to Interference plus Noise Ratio threshold value SINR _Th

The thresholding comparing module is used for every at a distance from T coherence time _cJust with current correlation between channels ρ and Signal to Interference plus Noise Ratio SINR respectively with correlation threshold value ρ _ThWith Signal to Interference plus Noise Ratio threshold value SINR _ThCompare, and the optimum sending mode in this coherence time that will choose is delivered in the feedback module;

Feedback module is used for the optimum sending mode that receiver is selected and feeds back to transmitter through based on feedback link, and delivers to the receiving terminal mode switch module.

In order to reduce the complexity of calculating; The utility model can each sending mode of double counting when channel condition is constant capacity, and can compare the sending mode that judgement should be adopted according to the value of current correlation and Signal to Interference plus Noise Ratio and the threshold value of correlation and Signal to Interference plus Noise Ratio.Be that the utility model also includes a channel condition judge module, the input of this channel condition judge module links to each other with channel estimation module, and its output links to each other with the thresholding comparing module with the calculation of capacity module respectively.This channel condition judge module is connected to the calculation of capacity module with the output of channel estimation module when judging that channel condition changes; And when judging that channel condition does not change, then the output of channel estimation module is connected to the thresholding determination module.

Claims (2)

1. multiple input multiple output adaptive mode-changeover device, the transmission antenna group that comprises transmitter, is made up of a plurality of transmitting antennas, receiver and by the reception antenna group that a plurality of reception antennas constitute is characterized in that,

Said transmitter mainly is made up of modulation and coding module, transmitting terminal mode switch module and sending module; Wherein be provided with spatial reuse sending mode unit, beam shaping sending mode unit and space and time diversity sending mode unit in the sending module; Modulation links to each other with sending module via the transmitting terminal mode switch module with coding module, and sending module connects transmission antenna group;

Said receiver mainly is made up of receiving terminal mode switch module, receiver module, modulation and decoder module, channel estimation module, calculation of capacity module, capacity comparing module, thresholding determination module, thresholding comparing module and feedback module; Wherein the reception antenna group is connected with channel estimation module with mode switch module; The output of mode switch module links to each other with decoder module with demodulation via receiver module; The output connection capacity computing module and the receiver module of channel estimation module; The output of calculation of capacity module is divided into 2 the tunnel, and wherein one the tunnel links to each other with feedback module via the capacity comparing module, and another road then links to each other with feedback module with the thresholding comparing module through the thresholding determination module successively; The output of feedback module is divided into 2 the tunnel, the one tunnel and directly links to each other with the receiving terminal mode switch module, and another road connects the transmitting terminal mode switch module via based on feedback link.

2. a kind of multiple input multiple output adaptive mode-changeover device according to claim 1; It is characterized in that; Also include a channel condition judge module; The input of this channel condition judge module links to each other with channel estimation module, and its output links to each other with the thresholding comparing module with the calculation of capacity module respectively.

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