CN101662340A - Method and device for computing equivalent signal-to-noise ratio and selecting modulation mode of MIMO system - Google Patents

Abstract

The invention discloses a method and a device for computing the equivalent signal-to-noise ratio and selecting the modulation mode of an MIMO system, belonging to the field of wireless communication and solving the problems of the inaccurate SNR computation and improper modulation mode selection of an ML receiver in the prior art. The embodiment can more accurately reflect the equivalent SNR of the ML receiver by utilizing minimum Euclidean distance and noise power to compute the equivalent SNR; meanwhile, in modulation mode selection, the embodiment firstly computes property parameters whichcorrespond to all the modulation modes and are related to the computed equivalent SNR, thus the finally selected modulation mode is more suitable for the ML receiver. The embodiment of the invention is mainly used for a wireless communication system and is especially used for the wireless communication system using the ML receiver.

Description

The snr computation of mimo system and modulation mode selection method and device

Technical field

The present invention relates to wireless communication system, relate in particular to that (multiple-input and multiple-output multi-input-multi-output) carries out in the wireless communication system of mode that equivalent signal-to-noise ratio calculates and the method and the device of modulation system selection adopting MIMO.

Background technology

In the wireless communication system, channel capacity increases along with the increase of antenna number, and MIMO (multiple-input and multiple-output) system is by placing many antennas respectively at transmitting terminal and receiving terminal place, with the spectrum efficiency of raising Radio Link and the reliability of Radio Link.In order effectively to utilize the mimo channel in the mimo system, the researcher has proposed the whole bag of tricks and has improved the mimo channel capacity, as Space Time Coding, precoding etc.

In cellular communication system, portable terminal need carry out signal to noise ratio (SNR to the downlink data that the base station sends to portable terminal usually, Signal to Noise Ratio) measurements and calculations, and SNR is carried among the CQI (channel-quality feedback) of up channel and feeds back to the base station, handle downlink data according to the modulation coding mode that the SNR among the CQI selects to be fit to the base station.Equally, the base station also needs to measure the SNR of upstream data, and be that portable terminal is selected suitable modulation coding mode according to SNR, and modulation coding mode information is sent to portable terminal by down control channel, so that portable terminal sends upstream data according to corresponding modulation coding mode.

As shown in Figure 1, be the structured flowchart of mimo system, n among the figure _TBe number of transmit antennas, n _RBe the reception antenna number, the signal s that transmission antennas transmit goes out ₁Extremely

Form n _TThe emission vector S of * 1 dimension, the signal x that reception antenna receives ₁Extremely

Form n _RThe reception vector X of * 1 dimension, the emission vector sum receives between the vector and satisfies following relation: X=HS+N.Wherein H is n _R* n _TThe channel matrix of dimension, the variance that on behalf of reception antenna, N receive is σ _n ²Gaussian noise vector.

Above-mentioned emission vector S satisfies:

Gaussian noise vector N satisfies: I representation unit matrix.

Mimo system with prior art 2 * 2 is the SNR computational methods and the modulation coding mode system of selection of example explanation below.

Specifically be expressed as follows in 2 * 2 mimo system by X=HS+N:

$\left(\begin{array}{c}{x}_1\\ x_2\end{array}\right)=\left(\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right)\left(\begin{array}{c}{s}_1\\ {\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">s</figure-callout>}}_2\end{array}\right)+\left(\begin{array}{c}{n}_1\\ {\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\end{array}\right)$

Under the prerequisite of not removing noise effect, the emission vector representation that calculates is as follows:

$\left(\begin{array}{c}{\hat{s}}_1\\ {\hat{s}}_2\end{array}\right)={(H^{H}H+{\mathrm{\&sigma;}}_n^2{I}_{n_T})}^{-1}{H}^H\left(\begin{array}{c}{x}_1\\ x_2\end{array}\right)=A\left(\begin{array}{c}{x}_1\\ x_2\end{array}\right)=\left(\begin{array}{cc}{a}_{11}& a_{12}\\ a_{21}& a_{22}\end{array}\right)\left(\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right)\left(\begin{array}{c}{s}_1\\ {\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">s</figure-callout>}}_2\end{array}\right)+\left(\begin{array}{cc}{a}_{11}& a_{12}\\ a_{21}& a_{22}\end{array}\right)\left(\begin{array}{c}{n}_1\\ {\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\end{array}\right)$

A=(H wherein ^HH) ^-1H ^H

After the following formula simplification, draw:

$\left(\begin{array}{c}{\hat{s}}_1\\ {\hat{s}}_2\end{array}\right)=\left(\begin{array}{c}{c}_{11}{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">s</figure-callout>}}_1+c_{12}{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">s</figure-callout>}}_2+d_{11}{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">n</figure-callout>}}_1+d_{12}{n}_2\\ c_{21}{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">s</figure-callout>}}_1+c_{22}{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">s</figure-callout>}}_2+d_{21}{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">n</figure-callout>}}_1+d_{22}{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\end{array}\right)$

Because the element of the emission vector that aforementioned calculation goes out

Expression formula in have only c ₁₁s ₁Be signal component, remaining all is a noise component(s); And for element Expression formula in have only c ₂₂s ₂Be signal component, remaining all is a noise component(s).So signal to noise ratio two-layer in this mimo system is expressed as follows respectively:

${\mathrm{<figure-callout\; id="1"\; label="SNR\; s"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">SNR</figure-callout>}}_{s_{}}=\frac{{\left|c_{11}\right|}^2{E}_s}{{\left|c_{12}\right|}^2{E}_s+({\left|d_{11}\right|}^2+{\left|d_{12}\right|}^2){\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}$

${\mathrm{<figure-callout\; id="2"\; label="SNR\; s"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">SNR</figure-callout>}}_{s_{}}=\frac{{\left|c_{21}\right|}^2}{{\left|c_{22}\right|}^2{E}_s+({\left|d_{21}\right|}^2+{\left|d_{22}\right|}^2){\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}$

If this mimo system adopts single codeword, then calculate the SNR of each layer earlier, utilize the SNR of each layer to calculate equivalent signal-to-noise ratio again.

Each Modulation and Coding Scheme will reach certain Packet Error Ratio need guarantee certain SNR, when given Packet Error Ratio, can obtain the SNR that adopts this Modulation and Coding Scheme to need by tabling look-up.From Modulation and Coding Scheme (MCS), select the required SNR of the QoS that reaches data demand all MCS, choose the MCS that can reach maximum transmission rate MCS at last as transmitting terminal less than the SNR that measures.

State in realization in the selection course of the calculating of SNR and MCS, the inventor finds that there are the following problems at least in the prior art:

Calculate SNR in the prior art and carry out the method that modulation system selects and to be applicable to MMSE (least-mean-square-error criterion), ZF linear receivers such as (zero forcing algorithms) according to SNR, for the so non-linear receiver of ML (maximum likelihood), adopt art methods accurately not calculate SNR, cause the selection of modulation system incorrect.Simultaneously, because the ML receiver is when modulation system changes, corresponding SNR also can change, thereby fully select the modulation system that will use in the prior art according to the SNR in the current modulation mode, will cause selected modulation system can not meet the demand of channel quality preferably.

Summary of the invention

Embodiments of the invention provide a kind of equivalent signal-to-noise ratio calculating and modulation mode selection method and device of mimo system, make can standard remove to calculate SNR when adopting the ML receiver, and select to reach the modulation system that sends the data service quality demand.

For achieving the above object, embodiments of the invention adopt following technical scheme:

A kind of equivalent signal-to-noise ratio computational methods of mimo system comprise:

Estimate the channel matrix of MIMO receiver;

Calculate the equivalent signal-to-noise ratio of each layer correspondence, this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision.

A kind of modulation mode selection method of mimo system comprises:

Obtain the modulation bit number of each layer correspondence in every kind of modulation mode combination;

Calculate the equivalent signal-to-noise ratio of each layer correspondence in every kind of modulation mode combination, this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination;

Determine the performance parameter of every kind of modulation mode combination according to described modulation bit number and equivalent signal-to-noise ratio;

Choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

A kind of equivalent signal-to-noise ratio calculation element of mimo system comprises:

Estimation unit is used to estimate the channel matrix of MIMO receiver;

Computing unit is used to calculate the equivalent signal-to-noise ratio of each layer correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision.

A kind of modulation mode selection device of mimo system comprises:

Acquiring unit is used for obtaining the modulation bit number of every kind of each layer of modulation mode combination correspondence;

Computing unit is used for calculating the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination;

Processing unit is used for determining according to described modulation bit number and equivalent signal-to-noise ratio the performance parameter of every kind of modulation mode combination;

Selected cell is used to choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

The equivalent signal-to-noise ratio calculating of the mimo system that the embodiment of the invention provides and modulation mode selection method and device, when carrying out the modulation system selection, at first to calculate the equivalent signal-to-noise ratio that determines by minimum Eustachian distance in every kind of modulation mode combination, and go out the performance parameter of corresponding M IMO system by this equivalence snr computation, select the modulation scheme of the modulation mode combination of performance parameter optimum at last as mimo system, because the equivalent signal-to-noise ratio of present embodiment is to be determined by minimum Eustachian distance between the received signal vector and noise power, go for nonlinear ML receiver, and draw the equivalent signal-to-noise ratio of ML receiver exactly, so the modulation scheme of selecting in the present embodiment is comparatively to be fit to the ML receiver, can satisfy the requirement of channel quality.

Description of drawings

Fig. 1 is the structured flowchart of mimo system;

Fig. 2 is the flow chart of the modulation mode selection method of mimo system in the embodiment of the invention 1;

Fig. 3 is the block diagram of the modulation mode selection device of mimo system in the embodiment of the invention 1;

Fig. 4 is the flow chart of the equivalent signal-to-noise ratio computational methods of mimo system in the embodiment of the invention 2;

Fig. 5 is the block diagram of the equivalent signal-to-noise ratio calculation element of mimo system in the embodiment of the invention 2;

Fig. 6 is the flow chart of the equivalent signal-to-noise ratio computational methods of mimo system in the embodiment of the invention 3;

Fig. 7 is the block diagram of the equivalent signal-to-noise ratio calculation element of mimo system in the embodiment of the invention 3;

Fig. 8 is the flow chart of the modulation mode selection method of mimo system in the embodiment of the invention 4;

Fig. 9 is the block diagram of the modulation mode selection device of mimo system in the embodiment of the invention 4;

Figure 10 is the flow chart of the modulation mode selection method of mimo system in the embodiment of the invention 5;

Figure 11 is the block diagram of the modulation mode selection device of mimo system in the embodiment of the invention 5;

The performance comparison figure of Figure 12 for adopting the system of selection of different modulating mode to draw.

Embodiment

Below in conjunction with accompanying drawing, the equivalent signal-to-noise ratio calculating of embodiment of the invention mimo system and modulation mode selection method and device are described in detail.

Embodiment 1:

Present embodiment provides a kind of equivalent signal-to-noise ratio computational methods of mimo system, and as shown in Figure 2, this method comprises the steps:

201, estimate the channel matrix of MIMO receiver.

202, calculate the equivalent signal-to-noise ratio that each layer receives the signal correspondence, this equivalence signal to noise ratio is determined by minimum Eustachian distance and the noise power that each layer receives between signal phasor, Euclidean distance is a factor of decision input error sign ratio, under the identical situation of other parameters, Euclidean distance is more little, and just to represent that signal is declared wrong probability big more, and the equivalent signal-to-noise ratio after the demodulation process is also just more little.

Corresponding to the equivalent signal-to-noise ratio computational methods of above-mentioned mimo system, present embodiment also provides a kind of equivalent signal-to-noise ratio calculation element of mimo system, and as shown in Figure 3, this device comprises: estimation unit 31 and computing unit 32.

Wherein, estimation unit 31 is used to estimate each channel matrix of MIMO receiver; Calculate the equivalent signal-to-noise ratio that each layer receives the signal correspondence by computing unit 32, this equivalence signal to noise ratio is determined by minimum Eustachian distance and the noise power that each layer receives between signal phasor.

For the ML receiver, the derivation of its equivalent signal-to-noise ratio is as follows:

The paired error sign ratio of k layer of ML receiver satisfies following formula:

$P(s^i\&RightArrow;s^j)\&le;\frac{1}{{\left(\frac{\mathrm{\&rho;}}{4N_T}{\left|\right|H(s^i-s^j)\left|\right|}_F^2\right)}^{N_R}}$

S wherein ⁱThe signal phasor of expression emission, s ^jThe signal phasor that obtains behind the expression receiver decision.

So the error sign ratio of receiver is:

$P_k\left(e\right)\&ap;\underset{s^i\&Element;S}{\mathrm{\&Sigma;}}P\left(s^i\right)\underset{s^j\&Element;S,s^j\left(k\right)\&NotEqual;s^i\left(k\right)}{\mathrm{\&Sigma;}}P(s^i\&RightArrow;s^j)$

P (s ⁱ) be s ⁱSending probability.

Can draw k layer bit error rate by the receiver error sign ratio is:

${\mathrm{BER}}_k\&ap;\underset{s^i\&Element;S}{\mathrm{\&Sigma;}}P\left(s^i\right)\underset{s^j\&Element;S,s^j\left(k\right)\&NotEqual;s^i\left(k\right)}{\mathrm{\&Sigma;}}\frac{{\mathrm{Bits}}_k(s^i,s^j)}{M_k}P(s^i\&RightArrow;s^j)$

Bits wherein _k(s ⁱ, s ^j) the expression vector s that transmits ⁱAnd s ^jK layer modulation symbol between different modulation bit numbers, M _kIt is the contained modulation bit number of k layer modulation coding mode.

For specific modulation coding mode combination, Bits _k(s ⁱ, s ^j) and M _kBe the value of determining, under the constant situation of transmit signal power and interference noise power, the bit error rate of k layer mainly by k layer element different transmit between the minimum Eustachian distance decision, promptly by

In denominator term in || H (s ⁱ-s ^j) || _F ²Decision.

If || H (s ⁱ-s ^j) || _F ²More little, be that Euclidean distance is more little, its corresponding bit error rate is just high more, so can calculate equivalent signal-to-noise ratio by minimum Euclidean distance in the present embodiment, so this step need be calculated the minimum Eustachian distance of each layer correspondence in every kind of modulation coding mode combination according to following formula.

Calculating below in conjunction with specific embodiment 2 explanation equivalent signal-to-noise ratios.

Embodiment 2:

Need carry out the calculating of signal to noise ratio when carrying out the CQI feedback, in order to calculate signal to noise ratio comparatively exactly when using the ML receiver, present embodiment provides a kind of equivalent signal-to-noise ratio computational methods of mimo system, and as shown in Figure 4, this method comprises the steps:

401, estimate the channel matrix of MIMO receiver.

402, the minimum Eustachian distance that calculates each layer correspondence according to the modulation system and the channel matrix of each layer.

When concrete the application, the calculating of minimum Eustachian distance comprises two kinds of situations, and is specific as follows:

The first, calculate each layer corresponding symbol level minimum Eustachian distance in every kind of modulation mode combination, k layer symbol level minimum Eustachian distance is

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver, the maximum number of plies is M.

The second, calculate the bit-level minimum Eustachian distance of each layer correspondence in every kind of modulation mode combination, the bit-level minimum Eustachian distance of k layer j bit is

S=[s wherein ₁, s ₂..., s _k(b _{K, 1}..., b _{K, j}...) ..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, b _{K, j}Be j bit of k layer, s '=[s ₁', s ₂' ..., s _k(b _{K, 1}' ..., b _{K, j}' ...) ..., s _M'] ^TBe the actual judgement of receiver received signal.

403, described minimum Eustachian distance is drawn equivalent signal-to-noise ratio divided by noise power, formula is as follows:

If what calculate in the step 402 is the symbol level minimum Eustachian distance, the equivalent signal-to-noise ratio that then draws is the symbol level equivalent signal-to-noise ratio, and concrete computing formula is:

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver, the maximum number of plies is M, σ ²Be noise power, that is: the interference and the thermal noise sum that are subjected to of receiver;

If what calculate in the step 402 is the bit-level minimum Eustachian distance, the equivalent signal-to-noise ratio that then draws is the bit-level equivalent signal-to-noise ratio, and concrete computing formula is:

S=[s wherein ₁, s ₂..., s _k(b _{K, 1}..., b _{K, j}...) ..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, b _{K, j}Be j bit of k layer, s '=[s ₁', s ₂' ..., s _k(b _{K, 1}' ..., b _{K, j}' ...) ..., s _M'] ^TBe the actual judgement of receiver received signal, the maximum number of plies is M, σ ²Be noise power, i.e. the interference and the thermal noise sum that are subjected to of receiver.

Corresponding to the signal-noise ratio computation method of above-mentioned mimo system, present embodiment also provides a kind of equivalent signal-to-noise ratio calculation element of mimo system, and as shown in Figure 5, this device comprises estimation unit 51 and computing unit 52.

Wherein, estimation unit 51 is used to measure the channel matrix of MIMO receiver; Computing unit 52 is used to calculate the signal to noise ratio that each layer receives the signal correspondence, and this signal to noise ratio is determined by minimum Eustachian distance and the noise power that each layer receives between signal.

When concrete utilization, described computing unit 52 comprises: first computing module 521 and second computing module 522.Described first computing module 521 at first calculates the minimum Eustachian distance that each layer receives the signal correspondence according to each layer modulation system and channel matrix.

If compute sign level minimum Eustachian distance, its computing formula is:

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver, the maximum number of plies is M.

If calculate the bit-level minimum Eustachian distance, its computing formula is:

S=[s wherein ₁, s ₂..., s _k(b _{K, 1}..., b _{K, j}...) ..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, b _{K, j}Be j bit of k layer, s '=[s ₁', s ₂' ..., s _k(b _{K, 1}' ..., b _{K, j}' ...) ..., s _M'] ^TBe the actual judgement of receiver received signal.

Second computing module 522 is used for described minimum Eustachian distance is drawn the signal to noise ratio that each layer receives the signal correspondence after divided by noise power.

Calculate signal to noise ratio by minimum Eustachian distance in the present embodiment, can reflect the performance of ML receiver comparatively exactly.

Embodiment 3:

Present embodiment provides a kind of modulation coding mode system of selection of mimo system, and as shown in Figure 6, this modulation coding mode system of selection comprises the steps:

601, obtain the modulation bit number of each layer correspondence in every kind of modulation mode combination, the modulation bit number here is exactly the bit number that comprises in the symbol that modulates, and the modulation bit that comprises in the symbol that modulates for different modulation systems is counted difference.

602, calculate the equivalent signal-to-noise ratio of each layer correspondence in every kind of modulation mode combination, this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination; Euclidean distance is a factor of decision input error sign ratio, and under the identical situation of other parameters, Euclidean distance is more little, and just to represent that signal is declared wrong probability big more, and the equivalent signal-to-noise ratio after the demodulation process is also just more little.

603, determine the performance parameter of every kind of modulation mode combination according to described modulation bit number and equivalent signal-to-noise ratio.

604, choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

Generally speaking, if adopt the mimo system of many code words, can determine this modulation mode combination corresponding coding manner by the equivalent signal-to-noise ratio that aforementioned calculation goes out; If adopt the mimo system of single codeword, after then in the end determining modulation mode combination, can determine SNR by modulation mode combination and the corresponding channel matrix chosen, and determine this modulation mode combination corresponding coding manner and code rate, embodiment 4 that concrete mode is stated as follows and embodiment 5 according to this SNR.

Corresponding to the system of selection of above-mentioned modulation system, present embodiment also provides a kind of modulation mode selection device of mimo system, and as shown in Figure 7, this device comprises: acquiring unit 71, computing unit 72, processing unit 73 and selected cell 74.

Wherein, acquiring unit 71 is used for obtaining the modulation bit number of every kind of each layer of modulation mode combination correspondence, and the modulation bit number is the modulation bit number that comprises in the symbol that modulates of different modulation systems; Computing unit 72 is used for calculating the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence, and this signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination; Processing unit 73 is used for the performance parameter of determining every kind of modulation mode combination according to the quality of service requirement of described modulation bit number, each layer data and equivalent signal-to-noise ratio; Selected cell 74 is used to choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

The modulation mode selection method of the mimo system that the embodiment of the invention provides and device, when carrying out the modulation system selection, at first to calculate in every kind of modulation mode combination by receiving the minimum Eustachian distance between signal phasor and the equivalent signal-to-noise ratio of noise power, and go out the performance parameter of corresponding M IMO system by this snr computation, select the modulation scheme of the modulation mode combination of performance parameter optimum at last as mimo system, because the signal to noise ratio of present embodiment is by minimum Eustachian distance and noise power decision, go for nonlinear ML receiver, and draw the SNR of ML receiver exactly, so the modulation scheme of selecting in the present embodiment is comparatively to be fit to the ML receiver, can satisfy the requirement of channel quality.

And since present embodiment in when selecting modulation mode, be the calculating of every kind of modulation mode combination all having been carried out performance parameter, current modulation mode can not occur ignoring in the prior art and the influence of SNR be selected the situation of the modulation system that will use, make that the selection of modulation system is more accurate.

Embodiment 4:

Present embodiment provides a kind of modulation mode selection method of mimo system, the application scenarios of present embodiment is the mimo system that adopts many codeword codings, when adopting many codeword codings, the capacity of mimo system is the capacity sum of each layer, therefore the selection of modulation system can decide by the total capacity of maximum, promptly this mimo system is weighed its performance by the mimo system capacity parameter, and as shown in Figure 8, this method comprises the steps:

801, in the mimo system of reality, each layer needs satisfy certain QoS (service quality), the capacity of this mimo system can be converted into the product that satisfies needed code rate of QoS and modulation bit number, so this method need be obtained the modulation bit number of each layer correspondence in every kind of modulation mode combination.

802, satisfy the needed code rate of QoS in order to draw, present embodiment need calculate the equivalent signal-to-noise ratio that mimo system need satisfy, for specific modulation mode combination, and Bits _k(s ⁱ, s ^j) and M _kBe the value of determining, under the constant situation of transmit signal power and noise power, the bit error rate of k layer mainly by k layer element different transmit between the minimum Eustachian distance decision, promptly by

In denominator term in || H (s ⁱ-s ^j) || _F ²Decision.

If || H (s ⁱ-s ^j) || _F ²More little, be that Euclidean distance is more little, its corresponding bit error rate is just high more, so can calculate equivalent signal-to-noise ratio by minimum Euclidean distance in the present embodiment, so this step need be calculated the minimum Eustachian distance of each layer correspondence in every kind of modulation coding mode combination according to following formula:

$d_{i,j}^k=\underset{s_k\&NotEqual;{s_k}^{\&prime;}}{\min }{\left|\right|\mathrm{Hs}-{\mathrm{Hs}}^{\&prime;}\left|\right|}_{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">F</figure-callout>}}^2$

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver.

803, get the equivalent signal-to-noise ratio that minimum euclidean distance and the ratio of noise power obtain the k layer

${\mathrm{SNR}}_k=\frac{\underset{s_k\&NotEqual;{s_k}^{\&prime;}}{\min }{\left|\right|\mathrm{Hs}-{\mathrm{Hs}}^{\&prime;}\left|\right|}^2}{{\mathrm{\&sigma;}}^2}.$

804, reaching under the prerequisite of qos requirement, determining each layer equivalent signal-to-noise ratio corresponding codes speed in every kind of modulation mode combination.

When determining code rate, can also determine every kind of modulation mode combination corresponding coding manner, every kind of modulation mode combination and its corresponding coding manner constitute modulation coding mode jointly like this.

805, respectively the modulation bit number and the code rate of each layer correspondence in the combination of every kind of modulation coding mode multiplied each other, formula is as follows:

M _iR (SNR _i), M wherein _iBe the modulation bit number of each layer correspondence, R (SNR _i) be each layer corresponding codes speed.

806, with multiplied result in the combination of every kind of modulation coding mode respectively addition obtain the mimo system capacity parameter, described mimo system capacity parameter is exactly the performance parameter of modulation coding mode combination in the present embodiment.

807, in general, the performance of big more this mimo system of expression of capacity is excellent more, so, choose the modulation coding mode combination of the modulation coding mode combination of described mimo system capacity parameter value maximum, comprised the modulation mode combination of required selection in the selected modulation coding mode combination as mimo system.

From above-mentioned steps 805 to step 807 as can be known, the capacity maximum of the modulation coding mode combination that present embodiment is selected, following formula is satisfied in the modulation coding mode of selecting combination:

$({\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">M</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">M</figure-callout>}}_2,...,M_N)=\underset{M_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; max\; M"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }\{M_{1}R\left({\mathrm{SNR}}_1\right)+M_{2}R\left({\mathrm{SNR}}_2\right)+...+M_{N}R\left({\mathrm{SNR}}_N\right)\}$

Wherein, M _iBe the modulation bit number of each layer correspondence, R (SNR _i) be each layer corresponding codes speed.

Corresponding to above-mentioned modulation mode selection method, present embodiment also provides a kind of modulation mode selection device of mimo system, and as shown in Figure 9, this device comprises: acquiring unit 91, computing unit 92, processing unit 93 and selected cell 94.

Acquiring unit 91 is used for obtaining the modulation bit number of every kind of each layer of modulation mode combination correspondence, i.e. the modulation bit number that comprises in the symbol that the different modulating mode modulates; Computing unit 92 is used for calculating the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal and noise power decision in every kind of modulation mode combination.

Comprise during described computing unit 92 specific implementations: first computing module 921 and second computing module 922.First computing module 921 is used for calculating the minimum Eustachian distance of every kind of each layer of modulation mode combination correspondence, and its computing formula is:

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver; Second computing module 722 is used for described minimum Eustachian distance is drawn equivalent signal-to-noise ratio divided by noise power.

Processing unit 93 is used for determining the performance parameter that every kind of modulation coding mode makes up according to described modulation bit number and equivalent signal-to-noise ratio, performance parameter in the present embodiment is the mimo system capacity parameter, in the specific implementation, described processing unit 93 comprises: pretreatment module 931, multiplier module 932 and addition module 933.Satisfying under the prerequisite of qos requirement, pretreatment module 931 is used for determining every kind of each layer of modulation mode combination equivalent signal-to-noise ratio corresponding codes speed, when determining code rate, described pretreatment module 931 can also be determined every kind of modulation mode combination corresponding coding manner, and every kind of modulation mode combination and its corresponding coding manner constitute modulation coding mode jointly like this. Multiplier module 932 is used for respectively the modulation bit number and the code rate of every kind of each layer of modulation coding mode combination correspondence are multiplied each other; Addition module 933 be used for every kind of modulation coding mode combination multiplied result respectively addition obtain the mimo system capacity parameter.Choose the modulation coding mode combination of the modulation coding mode combination of described mimo system capacity parameter value maximum by selected cell 94 then as mimo system.

The modulation system of the mimo system that the embodiment of the invention provides is selected and equivalent signal-to-noise ratio computational methods and device, when carrying out the modulation system selection, at first to calculate the equivalent signal-to-noise ratio that determines by minimum Eustachian distance in every kind of modulation mode combination, and determine code rate and coded system by the quality of service requirement of this equivalence signal to noise ratio and each layer data, calculate corresponding M IMO system capacity parameters again, select the modulation scheme of the modulation mode combination of capacity maximum at last as mimo system, because the equivalent signal-to-noise ratio of present embodiment is determined by minimum Eustachian distance, go for nonlinear ML receiver, and draw the SNR of ML receiver exactly, so the modulation scheme of selecting in the present embodiment is comparatively to be fit to the ML receiver, can satisfy the requirement of channel quality.

And since present embodiment in when selecting modulation mode, be the calculating of every kind of modulation mode combination all having been carried out capacity, current modulation mode can not occur ignoring in the prior art and the influence of SNR be selected the situation of the modulation system that will use, make that the selection of modulation system is more accurate.

Embodiment 5:

Present embodiment provides a kind of modulation coding mode system of selection of mimo system, the application scenarios of present embodiment is the mimo system that adopts the single codeword coding, when adopting the single codeword coding, owing to only there is an encoder, therefore the selection of modulation coding mode can decide by the bit signal to noise ratio of minimum, promptly this mimo system is recently weighed its performance by the bit noise of mimo system, and as shown in figure 10, this method comprises the steps:

1001, in the mimo system of reality, the bit signal to noise ratio of this mimo system can be converted into the product of equivalent signal-to-noise ratio and modulation bit number, so this method need be obtained the modulation bit number of each layer correspondence in every kind of modulation mode combination.

1002, present embodiment need calculate the equivalent signal-to-noise ratio that mimo system need satisfy, and for the ML receiver, k layer bit error rate is:

${\mathrm{BER}}_k\&ap;\underset{s^i\&Element;S}{\mathrm{\&Sigma;}}P\left(s^i\right)\underset{s^j\&Element;S,s^j\left(k\right)\&NotEqual;s^i\left(k\right)}{\mathrm{\&Sigma;}}\frac{{\mathrm{Bits}}_k(s^i,s^j)}{M_k}P(s^i\&RightArrow;s^j)$

Bits wherein _k(s ⁱ, s ^j) the expression vector s that transmits ⁱAnd s ^jK layer modulation symbol between different modulation bit numbers, M _kIt is the contained modulation bit number of k layer modulation system.

For specific modulation mode combination, Bits _k(s ⁱ, s ^j) and M _kBe the value of determining, under the constant situation of transmit signal power and noise power, the bit error rate of k layer mainly by k layer element different transmit between the minimum Eustachian distance decision, promptly by In denominator term in || H (s ⁱ-s ^j) || _F ²Decision.

If || H (s ⁱ-s ^j) || _F ²More little, be that Euclidean distance is more little, its corresponding bit error rate is just high more, so can calculate equivalent signal-to-noise ratio by minimum Euclidean distance in the present embodiment, so this step need be calculated the minimum Eustachian distance of each layer correspondence in every kind of modulation mode combination according to following formula:

$d_{i,j}^k=\underset{s_k\&NotEqual;{s_k}^{\&prime;}}{\min }{\left|\right|\mathrm{Hs}-{\mathrm{Hs}}^{\&prime;}\left|\right|}_{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">F</figure-callout>}}^2$

S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver.

1003, get the equivalent signal-to-noise ratio that minimum euclidean distance and the ratio of noise power obtain the k layer

${\mathrm{SNR}}_k=\frac{\underset{s_k\&NotEqual;{s_k}^{\&prime;}}{\min }{\left|\right|\mathrm{Hs}-{\mathrm{Hs}}^{\&prime;}\left|\right|}^2}{{\mathrm{\&sigma;}}^2}.$

1004, respectively the modulation bit number and the equivalent signal-to-noise ratio of each layer correspondence in every kind of modulation mode combination multiplied each other, formula is as follows:

M _iSNR _i, M wherein _iBe the modulation bit number of each layer correspondence, SNR _iEquivalent signal-to-noise ratio for each layer correspondence.

1005, choose one minimum value as mimo system minimum bit signal to noise ratio in the multiplied result of above-mentioned every kind of modulation mode combination, described mimo system minimum bit signal to noise ratio is exactly the performance parameter of modulation coding mode combination in the present embodiment.

1006, in general, the performance of big more this mimo system of expression of mimo system minimum bit signal to noise ratio is excellent more, so, choose the modulation mode combination of the modulation mode combination of described mimo system minimum bit signal to noise ratio maximum as mimo system.

From above-mentioned steps 1004 to step 1006 as can be known, present embodiment is selected the modulation mode combination of the bit signal to noise ratio maximum behind coding of transmission, promptly satisfies following formula:

$({\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">M</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">M</figure-callout>}}_2,...,M_N)=\underset{M_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; max\; M"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">arg</figure-callout>}\max }\left\{\min ({\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">M</figure-callout>}}_1{\mathrm{<figure-callout\; id="1"\; label="SNR"\; filenames="A2008102136600025H1.png"\; state="\{\{state\}\}">SNR</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">M</figure-callout>}}_2{\mathrm{<figure-callout\; id="2"\; label="SNR"\; filenames="A2008102136600029H2.png"\; state="\{\{state\}\}">SNR</figure-callout>}}_2,...,M_N{\mathrm{SNR}}_N)\right\}$

Wherein, M _iBe the modulation bit number of each layer correspondence, SNR _iBit-level equivalent signal-to-noise ratio for each layer correspondence.

For the single codeword mimo system, after having determined modulation mode combination, also need according to the modulation mode combination of selecting and definite equivalent MIMO capacity that can reach of channel matrix and corresponding SNR thereof, and determine this modulation mode combination corresponding codes speed and coded system according to this SNR, so just determined a complete modulation coding mode.

Corresponding to above-mentioned modulation coding mode system of selection, present embodiment also provides a kind of modulation coding mode choice device of mimo system, and as shown in figure 11, this device comprises: acquiring unit 111, computing unit 112, processing unit 113 and selected cell 114.

Acquiring unit 111 is used for obtaining the modulation bit number of every kind of each layer of modulation mode combination correspondence, i.e. the modulation bit number that comprises in the symbol that the different modulating coded system modulates; Computing unit 112 is used for calculating the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal and noise power decision in every kind of modulation mode combination.

Comprise during described computing unit 112 specific implementations: first computing module 1121 and second computing module 1122.First computing module 1121 is used for calculating the minimum Eustachian distance of every kind of each layer of modulation mode combination correspondence, and its computing formula is: S=[s wherein ₁, s ₂..., s _k..., s _M] ^TBe emission signal vector, s _kBe the emission symbol of k layer, s '=[s ₁', s ₂' ..., s _k' ..., s _M'] ^TBe the actual judgement vector of receiver; Second computing module 1122 is used for described minimum Eustachian distance is drawn equivalent signal-to-noise ratio after divided by noise power.

Processing unit 113 is used for determining according to described modulation bit number and equivalent signal-to-noise ratio the performance parameter of every kind of modulation mode combination, performance parameter in the present embodiment is a mimo system bit signal to noise ratio, in the specific implementation, described processing unit 113 comprises: multiplier module 1131 and choose module 1132.Described multiplier module 1131 is used for respectively the modulation bit number and the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence are multiplied each other, and selects to get the minimum value of multiplied result in every kind of modulation mode combination as mimo system bit signal to noise ratio by choosing module 1132 then.Described selected cell 114 is chosen the modulation mode combination of the modulation mode combination of described mimo system bit signal to noise ratio maximum as mimo system.

Since in the present embodiment when selecting modulation mode, be the calculating of every kind of modulation mode combination all having been carried out the bit signal to noise ratio, current modulation mode can not occur ignoring in the prior art and the influence of SNR be selected the situation of the modulation system that will use, make that the selection of modulation system is more reasonable.

For the single codeword mimo system, after having determined modulation mode combination, also need according to the modulation mode combination of selecting and definite equivalent MIMO capacity that can reach of channel matrix and corresponding SNR thereof, and determine this modulation mode combination corresponding codes speed and coded system according to this SNR, so just determined a complete modulation coding mode.

Present embodiment has adopted the equivalent signal-to-noise ratio by the minimum Eustachian distance decision when calculating the bit equivalent signal-to-noise ratio, minimum Eustachian distance can reflect the performance of non-linear receivers such as ML comparatively exactly, so make the modulation coding mode chosen in the present embodiment more accurately and be fit to the ML receiver.

Because present embodiment adopts method comparatively accurately in selecting modulation mode, can improve the capacity of mimo system in the present embodiment like this, as shown in figure 12, in modulation bit is under the situation of 3bits, its SNR is that the SNR of 2bits is little than modulation bit also, so the modulation system of selecting in the present embodiment can improve the capacity of mimo system.

Can improve the performance of mimo system in the mimo system by modes such as precodings, as reduce the complexity of receiver or improve the mimo system capacity, at the foregoing description 1, embodiment 2, embodiment 3, can carry out precoding among embodiment 4 and the embodiment 5, under the situation that adopts precoding, the equivalence of pre-coding matrix and channel matrix can being joined together is a new equivalent channel matrix H ', with H ' replacement embodiment 1, embodiment 2, embodiment 3, channel matrix H among embodiment 4 and the embodiment 5 can be finished corresponding snr computation, and perhaps modulation coding mode is selected.

The embodiment of the invention is mainly used in the wireless communication system, is specially adapted to adopt the wireless communication system of ML receiver.

Through the above description of the embodiments, the those skilled in the art can be well understood to the present invention and can realize by the mode that software adds essential common hardware, can certainly pass through hardware, but the former is better execution mode under a lot of situation.Based on such understanding, the part that technical scheme of the present invention contributes to prior art in essence in other words can embody with the form of software product, this computer software product is stored in the storage medium that can read, floppy disk as computer, hard disk or CD etc., comprise some instructions with so that computer equipment (can be personal computer, server, the perhaps network equipment etc.) carry out the described method of each embodiment of the present invention.

The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion by described protection range with claim.

Claims (19)

1, a kind of equivalent signal-to-noise ratio computational methods of mimo system is characterized in that, comprising:

Estimate the channel matrix of MIMO receiver; Calculate the equivalent signal-to-noise ratio of each layer correspondence, this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision.

2, the equivalent signal-to-noise ratio computational methods of mimo system according to claim 1 is characterized in that, the equivalent signal-to-noise ratio that described each layer of calculating receives the signal correspondence comprises:

The minimum Eustachian distance that calculates each layer correspondence according to the modulation system and the channel matrix of each layer;

Described minimum Eustachian distance is drawn the equivalent signal-to-noise ratio that each layer receives the signal correspondence divided by noise power.

3, the equivalent signal-to-noise ratio computational methods of mimo system according to claim 1 is characterized in that, further comprise: when adopting precoding, described pre-coding matrix and described channel matrix are joined together as equivalent channel matrix.

4, the equivalent signal-to-noise ratio computational methods of mimo system according to claim 3 is characterized in that, the equivalent signal-to-noise ratio that described each layer of calculating receives the signal correspondence is specially:

The minimum Eustachian distance that obtains each layer correspondence according to the modulation system and the described equivalent channel matrix of each layer;

Described minimum Eustachian distance is drawn the equivalent signal-to-noise ratio that each layer receives the signal correspondence divided by noise power.

5, the equivalent signal-to-noise ratio computational methods of mimo system according to claim 2, it is characterized in that, described minimum Eustachian distance is the symbol level minimum euclidean distance of received signal, the bit-level minimum euclidean distance that perhaps described minimum Eustachian distance is a received signal.

6, a kind of modulation mode selection method of mimo system is characterized in that, comprising:

Obtain the modulation bit number of each layer correspondence in every kind of modulation mode combination;

Calculate the equivalent signal-to-noise ratio of each layer correspondence in every kind of modulation mode combination, this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination;

Determine the performance parameter of every kind of modulation mode combination according to described modulation bit number and equivalent signal-to-noise ratio;

Choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

7, the modulation mode selection method of mimo system according to claim 6 is characterized in that, the equivalent signal-to-noise ratio that calculates each layer correspondence in every kind of modulation mode combination comprises:

Calculate the minimum Eustachian distance between each layer received signal vector in every kind of modulation mode combination;

Described minimum Eustachian distance is drawn equivalent signal-to-noise ratio divided by the noise power sum.

According to the modulation mode selection method of claim 6 or 7 described mimo systems, it is characterized in that 8, described mimo system adopts many code words mimo system, described performance parameter is the mimo system capacity parameter;

Determine that according to described modulation bit number and equivalent signal-to-noise ratio the performance parameter of every kind of modulation mode combination comprises:

Determine each layer equivalent signal-to-noise ratio corresponding codes speed in every kind of modulation mode combination;

Modulation bit number and code rate with each layer correspondence in every kind of modulation mode combination multiplies each other respectively;

With multiplied result in every kind of modulation mode combination respectively addition obtain the mimo system capacity parameter.

9, the modulation mode selection method of mimo system according to claim 8, it is characterized in that the modulation mode combination of choosing described performance parameter optimum as the modulation mode combination of mimo system is: choose the modulation mode combination of the modulation mode combination of described mimo system capacity parameter value maximum as mimo system.

10, according to the modulation mode selection method of claim 6 or 7 described mimo systems, it is characterized in that, described mimo system adopts the single codeword mimo system, and described performance parameter is that mimo system is the minimum bit signal to noise ratio behind the coding, and described equivalent signal-to-noise ratio is the bit-level equivalent signal-to-noise ratio;

Determine that according to described modulation bit number and bit-level equivalent signal-to-noise ratio the performance parameter of every kind of modulation mode combination comprises:

Modulation bit number and bit-level equivalent signal-to-noise ratio with each layer correspondence in every kind of modulation mode combination multiplies each other respectively;

The minimum value of getting multiplied result in every kind of modulation mode combination is as mimo system minimum bit signal to noise ratio.

11, the modulation mode selection method of mimo system according to claim 10, it is characterized in that the modulation mode combination of choosing described performance parameter optimum as the modulation mode combination of mimo system is: choose the modulation mode combination of the modulation mode combination of described mimo system minimum bit signal to noise ratio maximum as mimo system.

12, a kind of equivalent signal-to-noise ratio calculation element of mimo system is characterized in that, comprising:

Estimation unit is used to estimate the channel matrix of MIMO receiver;

Computing unit is used to calculate the equivalent signal-to-noise ratio of each layer correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision.

13, the equivalent signal-to-noise ratio calculation element of mimo system according to claim 12 is characterized in that, described computing unit comprises:

First computing module is used for calculating according to each layer modulation system and channel matrix the minimum Eustachian distance of each layer correspondence;

Second computing module is used for described minimum Eustachian distance is drawn after divided by the noise power sum equivalent signal-to-noise ratio of each level number correspondence.

14, a kind of modulation mode selection device of mimo system is characterized in that, comprising:

Acquiring unit is used for obtaining the modulation bit number of every kind of each layer of modulation mode combination correspondence;

Computing unit is used for calculating the equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence, and this equivalence signal to noise ratio is by minimum Eustachian distance between each layer received signal vector and noise power decision in every kind of modulation mode combination;

Processing unit is used for determining according to described modulation bit number and equivalent signal-to-noise ratio the performance parameter of every kind of modulation mode combination;

Selected cell is used to choose the modulation mode combination of the modulation mode combination of described performance parameter optimum as mimo system.

15, the modulation mode selection device of mimo system according to claim 14 is characterized in that, described computing unit comprises:

First computing module is used for calculating every kind of minimum Eustachian distance between each layer of modulation mode combination received signal vector;

Second computing module is used for described minimum Eustachian distance is drawn equivalent signal-to-noise ratio after divided by noise power.

According to the modulation mode selection device of claim 14 or 15 described mimo systems, it is characterized in that 16, described performance parameter is the mimo system capacity parameter; Described processing unit comprises:

Pretreatment module is used for determining every kind of each layer of modulation mode combination equivalent signal-to-noise ratio corresponding codes speed according to the quality of service requirement of each layer;

Multiplier module is used for respectively the modulation bit number and the code rate of every kind of each layer of modulation mode combination correspondence are multiplied each other;

Addition module, be used for every kind of modulation mode combination multiplied result respectively addition obtain the mimo system capacity parameter.

17, the modulation mode selection device of mimo system according to claim 16 is characterized in that,

Described selected cell is chosen the modulation mode combination of the modulation mode combination of described mimo system capacity parameter value maximum as mimo system.

According to the modulation coding mode choice device of claim 14 or 15 described mimo systems, it is characterized in that 18, described performance parameter is a mimo system minimum bit signal to noise ratio, described equivalent signal-to-noise ratio is the bit-level equivalent signal-to-noise ratio; Described processing unit comprises:

Multiplier module is used for respectively the modulation bit number and the bit-level equivalent signal-to-noise ratio of every kind of each layer of modulation mode combination correspondence are multiplied each other;

Choose module, be used for choosing the minimum value of every kind of modulation mode combination multiplied result as mimo system minimum bit signal to noise ratio.

19, the modulation mode selection device of mimo system according to claim 18 is characterized in that,

Described selected cell is chosen the modulation mode combination of the modulation mode combination of described mimo system minimum bit signal to noise ratio maximum as mimo system.

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