CN103532671B - MIMO-OFDM systematic bits distribution method based on delayed channel status information - Google Patents

Abstract

MIMO ofdm system Bit distribution method based on delayed channel status information, including: estimate current actual channel according to the channel condition information of time delay；Calculate the constellation distance parameter of spatial sub-channel

Description

MIMO-OFDM systematic bits distribution method based on delayed channel status information

Technical field

The present invention relates to wireless communication system resource allocation techniques, especially for the one of MIMO-OFDM system physical layer Bit distribution method based on delayed channel status information.

Background technology

The development of various wireless communication systems such as cellular mobile communications networks, WLAN and Metropolitan Area Network (MAN) quickly, but also face Facing the various challenges of constantly arrival, its root problem is that user constantly carries what service quality (speed, the bit error rate etc.) required Contradiction between the transmittability that high and wireless channel is limited.Data service, the growth of multimedia service, make this contradiction more Prominent.But wireless channel belongs to time-varying fading channels, and be band limit, its finite capacity and also random.In the face of business is many The trend that quality of service requirement is improved constantly by sample, user, it is necessary to make system wireless resource give play to the effect of maximum as far as possible With, one of technology for self-adaptively transmitting key technology becoming wireless communication system.

Technology for self-adaptively transmitting, according to the adaptive adjustment such as channel, network condition various transmission parameter, reaches system speed The targets such as rate maximization or power consumption minimize, such as adaptive coding and modulating, adaptive tracking control etc..

The distribution of MIMO-OFDM systematic bits falls within the category of Adaptive Transmission, and it is according to the channel status of transmission time Adaptive special for every sub-channels distribution ratio, make system emission power minimize while meeting quality of service requirement.Pass The channel condition information obtained by feedback is directly used in Adaptive Transmission by the Bit distribution method of system, does not accounts for owing to connecing The time delay that receipts machine channel estimation, feedback etc. produce, often leads to the channel information of feedback and actual letter in time-varying fading channels Mismatch between road state, produces transmission error and performance loss.On the other hand, the most traditional Bit distribution method complexity The highest, although having reached excellent performance, but implemented highly difficult in real-time communication system, hardware, software cost are also The highest.

Summary of the invention

It is an object of the present invention to provide a kind of reduce algorithm complex and keep performance that communication system is more excellent based on prolonging Time channel condition information MIMO-OFDM systematic bits distribution method, its concrete technical scheme is as follows:

Described systematic bits distribution method, it is characterised in that including:

Transmitting terminal, according to the channel condition information of time delay, estimates current actual channel；

According to currently practical channel and the error rate BER requirement estimated, calculate the constellation of each MIMO spatial sub-channel away from From parameter

According to the feature of MIMO-OFDM channel, all spatial sub-channels are divided into two groups, and determine the bit that two components are joined The distribution of number；

Bit number distribution, the total rate requirement of system determined by Yi Ju, by total for system rate-allocation to two groups, and distribute every Group bit distribution parameter；

According to each group of speed distributed and the constellation distance parameter of spatial sub-channel, for each spatial sub-channel meter in group Bit number that point counting is joined and launch power accordingly；

Wherein n represents subcarrier sequence number, n=1,2 ... N_C。

Described systematic bits distribution method further designs and is, the channel condition information of described time delay is that transmitting terminal leads to Cross sending from receiving terminal of feedback channel acquisition and comprise N_CThe channel condition information H of individual subcarrier^fN (), when occurring with bit transfer Channel H (n) compare, the channel condition information H of time delay^fN () is to have certain time delayed channel condition information.

Described systematic bits distribution method further designs and is, the channel status letter of the time delay that described transmitting terminal obtains Breath H^fCorrelation coefficient ρ is there is between (n) and present channel H (n)

ρ=J₀(2πf_DT_delay)；

Wherein: J₀() first kind Oth order Bessel function, T_delayFor feedback delay, f_DFor Doppler frequency displacement.

Described systematic bits distribution method further designs and is, described transmitting terminal is according to the channel condition information of time delay Estimate present channelParticularly as follows:

$\hat{H}\left(n\right)=\mathrm{\ρ}{H}^f\left(n\right)+\mathrm{\Ξ}\left(n\right),n=\mathrm{0,1},...,N_C-1$

Wherein: Ξ (n) is the random matrix of estimation difference, multiple Gauss distribution is obeyed It it is letter The variance of estimaion error of each element in road matrix, It is the average power gain of wireless link, f_DFor Doppler frequency displacement, T_delayFor feedback delay.

Described systematic bits distribution method further designs and is, the constellation distance of each spatial sub-channel of described calculating ParameterIncluding:

Respectively to channel matrixWith H^fN () carries out singular value decomposition, and H^f(n), H (n) withIt is all N_T×N_RSquare Battle array, then singular value decomposition is,

$\begin{array}{c}{\mathrm{\ρH}}^f\left(n\right)=\stackrel{\‾}{U}\left(n\right)\stackrel{\‾}{\mathrm{\Λ}}\left(n\right){\stackrel{\‾}{V}}^H\left(n\right)\\ ={\mathrm{\Σ}}_{i=1}^{M_S}{\stackrel{\‾}{u}}_i\left(n\right){\stackrel{\‾}{\mathrm{\λ}}}_i\left(n\right){\stackrel{\‾}{v}}_i^H\left(n\right)\end{array},$

$\begin{array}{c}\hat{H}\left(n\right)=\stackrel{\‾}{U}\left(n\right)\widehat{\mathrm{\Λ}}\left(n\right){\stackrel{\‾}{V}}^H\left(n\right)\\ ={\mathrm{\Σ}}_{i=1}^{M_S}{\stackrel{\‾}{u}}_i\left(n\right){\widehat{\mathrm{\λ}}}_i\left(n\right){\stackrel{\‾}{v}}_i^H\left(n\right)\end{array};$

Calculate least square Euclidean distance

$d_{i,E}^2\left(n\right)=4g\left(b_i\left(n\right)\right)P_i\left(n\right)T_s;$

Normalized squared euclidean distance parameter

$\begin{array}{c}{d}_i^2\left(n\right)=d_{i,E}^2\left(n\right)/\left({4T}_s\right)\\ =g\left(b_i\left(n\right)\right)P_i\left(n\right)\end{array};$

Determine the error rate BER of approximation on the channel of i-th subspace_i(n)

${\mathrm{BER}}_i\left(n\right)\≈0.2\·\exp ({-\mathrm{\λ}}_i^2\left(n\right)d_i^2\left(n\right)/{\mathrm{\σ}}^2)$

Determine the average error rate on the channel of i-th subspace

${\stackrel{\‾}{\mathrm{BER}}}_i\left(n\right)\≈0.2{\left(\frac{1}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2}\right)}^{N_R}\·\exp \left(\frac{{\stackrel{\‾}{\mathrm{\λ}}}_i^2\left(n\right)d_i^2\left(n\right)/{\mathrm{\σ}}^2}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2}\right)$

Target error rate in given i-th subchannelReach the minimum needed for target error rateCan With from above-mentionedTry to achieve；

Wherein:For singular value,For the average of singular value, andForStochastic variable；

M_TAnd M_RRepresent that transmitting and receiving terminal are respectively configured the number of antenna respectively；M_SIt is that H (n) carries out singular value decomposition generation Spatial sub-channel number, M_S=min(M_T,M_R)；It is to ρ H respectively^fWhen () carries out singular value decomposition n The left singular matrix of generation, singular value matrix, right singular matrix；It is to ρ H respectively^fN () carries out singular value decomposition Time produce left singular vector, right singular vector g (b) be the function about bit number b, $g\left(b\right)=\left\{\begin{array}{c}\frac{6}{5\·2^b-4},b=1,3,5,...\\ \frac{6}{4\·2^b-4},b=\mathrm{2,4,6},...\end{array}\right.,$ b_i(n)、P_iN () is the bit number and power that on the n-th subcarrier, i-th spatial sub-channel loads respectively, before TS is removal circulation The OFDM symbol cycle after sewing.

Described systematic bits distribution method further designs and is, the method that described all spatial sub-channels are divided into two groups Including:

Spatial sub-channel 1 and spatial sub-channel 2 on each OFDM carrier wave are subdivided into first group, and other subchannels are subdivided into Second group；

If only two spatial sub-channels on each OFDM carrier wave, then subchannel 1 is subdivided into first group, subchannel 2 strokes It is divided into second group.

Described systematic bits distribution method further designs and is, the distribution of the bit number that described two components are joined includes: b_maxWith b_max-2；b_max-2 and b_max-4；b_maxIt is to treat bit number and for even number.

Described systematic bits distribution method further designs and is, the determination bag of the design parameter of described bit number distribution Include:

A. b is made_max=4；

B. first group of whole subchannel loads b_max-2 bits, second group all loads b_max-4 bits；

If c. in step b, gained bit number less than 0, is then taken as 0 bit, total speed R that two groups of channels reach_total；

If d. R_total>R_need, enter next step e；Otherwise b_max=b_max+ 2, return b；

e.b_max=b_max-2；

Then: the bit number that two components are joined is respectively b_maxWith b_max-2 and b_max-2 and b_max-4；

If negative value occurs in above-mentioned bit number, then it is taken as 0 bit, i.e. ensures that the bit number of distribution is nonnegative value.

Described systematic bits distribution method further designs and is, in described group, each spatial sub-channel calculates and distributed The method of bit number include:

A. first group of subchannel is made all to load b_maxThe speed that-2 bits are reached is R_a, second group of subchannel all adds Carry b_maxThe speed that-4 bits are reached is R_b, then remaining bits is R_rem=R_need-R_a-R_b；

B. it is the first component proportion spy number R₁=R_a+ R_rem/ 2, second component joins bit number R₂=R_b+ R_rem/2；

Described systematic bits distribution method further designs and is, in described group, each spatial sub-channel is according to distribution phase The method launching power answered includes:

Setting pth (p=1,2) is organized interior two bit numbers and is respectively b_upWith b_low, and total bit number that this component is joined is R_p。

To own in groupAscending order arranges, and forms array $d=[d_{i.1}^2\left(j\right),...,d_{i,m}^2\left(k\right),...,d_{i,N}^2\left(l\right)];$

To (R_p-b_low)/2 round up, and obtain Integer N₁, then front N in array₁IndividualCorresponding subchannel all loads b_upBit；Residue subchannel all loads b_lowBit；

Bit number according to loading in subchannel obtains corresponding power demand factor F, is launched power accordingly

The transmitting power of all subchannels is sued for peace, just obtains the transmitting power of system.

The present invention utilizes the channel condition information of time delay calculate constellation distance parameter and consider the impact of time delay, thus reduces The impact of channel mismatch；Utilize the feature of OFDM/MIMO channel, simple and effective achieve channel packet, reduce algorithm Complexity；By distribution two-step method in distributing between group, organizing, reduce the complexity of bit distribution, final acquisition each space Bit number on channel and launch power accordingly.Thus, the following Advantageous Effects of the inventive method generation: 1) always reduce Launch power；2) complexity that in communication system, bit loads is reduced；3) CSI mismatch and the algorithm produced due to time delay is avoided Can reduce.

Detailed description of the invention

Below according to specific embodiment, the present invention is described further.

The systematic bits distribution method of the present invention mainly includes following step:

1) current actual channel is estimated

Transmitting terminal is received from receiving terminal and sends and comprise N_CCurrent channel condition information H (n) of individual subcarrier is logical by feedback Road obtains the channel condition information H with time delay^fN (), transmitting terminal is according to the channel condition information H of time delay^fN (), estimates current Actual channel

2) constellation distance parameter is calculated

According to currently practical channel and the error rate BER requirement estimated, calculate the constellation of each MIMO spatial sub-channel away from From parameter

3) subchannel packet and distribution often group bit distribution parameter

Determined by Yi Ju, bit number distribution, the total rate requirement of system, by total for system rate-allocation to two groups, and determine ratio Special distributed constant；

4) bit number that distributes and launch power accordingly

According to each group of speed distributed, and the constellation distance parameter of spatial sub-channel, for letter in each space in group Road calculates the bit number distributed and launches power accordingly.

The channel condition information H of the described time delay in above-mentioned steps^fN () refers to channel phase when occurring with bit transfer Ratio, has the channel condition information that certain time is delayed.In frequency division duplex system, arrive transmitting terminal through feedback channel.Use Jakes model describes channel time varying characteristic, and feedback delay is T_delaySecond, Doppler frequency displacement is f_D.The letter that so transmitting terminal obtains Channel state information H^fN () i.e. has the channel condition information of time delay, the correlation coefficient between it and present channel H (n) is ρ=J₀(2π f_DT_delay), J₀() is first kind Oth order Bessel function.Transmitting terminal is according to H^fN () estimates that present channel is

$\hat{H}\left(n\right)=\mathrm{\ρ}{H}^f\left(n\right)+\mathrm{\Ξ}\left(n\right),n=\mathrm{0,1},...,N_C-1---\left(1\right)$

In formula (1), Ξ (n) is the random matrix characterizing estimation difference, obeys multiple Gauss distribution It is the variance of estimaion error of each element in channel matrix, It it is the mean power increasing of wireless link Benefit.

The subchannel of the present invention is MIMO spatial sub-channel, and it is to pass through singular value decomposition on each OFDM subcarrier (SVD) spatial sub-channel produced.Assume that MIMO-OFDM system is respectively configured M in transmitting and receiving terminal_TAnd M_RIndividual antenna, total N_CIndividual subcarrier；The frequency selective fading that statistical property is identical is experienced between every pair of send-receive antenna.So, through transmitting-receiving After the Combined Treatment of two ends, the n-th subcarrier obtains flat fading MIMO channel matrix H (n)=[H_μν(n)],1≤μ≤M_T,1 ≤ν≤M_R.If antenna distance is enough remote, H_μνBy orthogonal between (n).H (n) carries out singular value decomposition (SVD) produce M_S=min(M_T,M_R) individual spatial sub-channel, i.e.

$\begin{array}{c}H\left(n\right)=U\left(n\right)\mathrm{\Λ}\left(n\right)V^H\left(n\right)\\ ={\mathrm{\Σ}}_{i=1}^{M_S}{u}_i\left(n\right){\mathrm{\λ}}_i\left(n\right)v_i^H\left(n\right)\end{array}---\left(2\right)$

In formula (2), λ i (n) is the singular value arranged in descending order, u_i(n) and v_iN () is the left/right corresponding with λ i (n) respectively Singular vector.

Described constellation distanceWhen referring to use qam constellation on spatial sub-channel, through normalized squared euclidean distance Parameter.The OFDM symbol cycle after Cyclic Prefix of removing is T_S, the ratio of i-th spatial sub-channel loading on the n-th subcarrier Special number and power are { b_i(n),P_i(n)}.Under conditions of using square and rectangle qam constellation, the least square Euclidean of constellation Distance is

$d_{i,E}^2\left(n\right)=4g\left(b_i\left(n\right)\right)P_i\left(n\right)T_s---\left(1\right)$

Wherein

$g\left(b\right)=\left\{\begin{array}{c}\frac{6}{5\·2^b-4},b=1,3,5,...\\ \frac{6}{4\·2^b-4},b=\mathrm{2,4,6},...\end{array}\right.---\left(2\right)$

Normalized squared euclidean distance parameter is

$\begin{array}{c}{d}_i^2\left(n\right)=d_{i,E}^2\left(n\right)/\left({4T}_s\right)\\ =g\left(b_i\left(n\right)\right)P_i\left(n\right)\end{array}---\left(3\right)$

After defining normalized squared euclidean distance parameter, the bit error rate (BER) in subchannel i can be approximated to be

${\mathrm{BER}}_i\left(n\right)\≈0.2\·\exp ({-\mathrm{\λ}}_i^2\left(n\right)d_i^2\left(n\right)/{\mathrm{\σ}}^2)---\left(4\right)$

σ in above formula²It it is the noise power on spatial sub-channel i.

To estimated value based on delayed channel status informationCarry out singular value decomposition as follows

$\begin{array}{c}\hat{H}\left(n\right)=\stackrel{\‾}{U}\left(n\right)\widehat{\mathrm{\Λ}}\left(n\right){\stackrel{\‾}{V}}^H\left(n\right)\\ ={\mathrm{\Σ}}_{i=1}^{M_S}{\stackrel{\‾}{u}}_i\left(n\right){\widehat{\mathrm{\λ}}}_i\left(n\right){\stackrel{\‾}{v}}_i^H\left(n\right)\end{array}---\left(5\right)$

So average BER on the channel of i-th subspace is

${\stackrel{\‾}{\mathrm{BER}}}_i\left(n\right)\≈0.2{\left(\frac{1}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2}\right)}^{N_R}\·\exp \left(\frac{{\stackrel{\‾}{\mathrm{\λ}}}_i^2\left(n\right)d_i^2\left(n\right)/{\mathrm{\σ}}^2}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2}\right)---\left(6\right)$

Target error rate in given i-th subchannelReach the minimum needed for target error rateCan To try to achieve on the basis of formula (8).

Bit distribution between spatial sub-channel packet and group: in an ofdm system, has change continuously between its sub-carrier channels The feature changed.And in mimo channel, two the strongest spatial sub-channels have bigger gain, itsAlso relatively other spaces Subchannel is much smaller.From the two feature, all spatial sub-channels are divided in order two groups: each OFDM carrier wave On spatial sub-channel 1 and spatial sub-channel 2 be subdivided into first group, other subchannels are subdivided into second group.Within so two groupsDynamic range within 16 times；Between two groupsThere is certain overlapping region.When all channels in group Dynamic range within 16 times, can be approximately considered in each subchannel load bit number be one of two continuous print even numbers, Compared with optimal bit loading method, the excess power caused increases minimum.Set the bit number of two groups of subchannels the most accordingly It is respectively: b_maxWith b_max-2 and b_max-2 and b_max-4(b_maxIt is an even number undetermined).The ratio transmitted the most as required Special sum R_need, and often organize the constellation distance in subchannelDetermine bit distribution parameter b_max。

Determine two groups of respective speed R of channel₁、R₂: in two groups, all subchannels load b respectively_max-2、b_max-4 bits it After, if the most remaining bit, then use the criterion of remaining bits mean allocation, by remaining bit average mark between two groups Join, obtain two groups of respective speed R of channel₁、R₂, specifically include:

A. first group of subchannel is made all to load b_maxThe speed that-2 bits are reached is R_a, second group of subchannel all adds Carry b_maxThe speed that-4 bits are reached is R_b, then remaining bits is R_rem=R_need-R_a-R_b；

B. it is the first component proportion spy number R₁=R_a+ R_rem/ 2, second component joins bit number R₂=R_b+ R_rem/2；

Distribute all bits according to two way classification in often organizing, be that all subchannels calculate sending out of needs according to the bit number of distribution Penetrate power, specifically include:

A. two groups respectively according to two way classification bit loading, if pth (p=1,2) is organized interior two bit numbers and is respectively b_upWith b_low； R_pIt it is the total bit number joined for pth component；

B. will own in groupAscending order arranges, and forms arrayM in subscript Being element sequence number in array d, the letter in round parentheses is the sequence number of its place subcarrier；

C. to (R_p-b_low)/2 round up, and obtain Integer N₁, then front N in array₁IndividualCorresponding subchannel all adds Carry b_upBit；Residue subchannel all loads b_lowBit；

D. corresponding power demand factor F is obtained according to the bit number loaded in subchannel from table 1 below, by calculatingLaunched power accordingly.

E. the transmitting power of all subchannels is sued for peace, just obtain the transmitting power of system.

At present in real system, modulate the bit number used by a symbol less than 10.

It is assigned with bit for each spatial sub-channel the most according to the method described above within two groups, and calculates corresponding transmitting respectively Power；The bit number sum that all subchannels load is targeted rate R of system_need, the transmitting power of all subchannels it Be system always launch power.

The bit loading method of the present invention is each subchannel of physical layer, OFDM each carrier wave suitable bit number of distribution, in order to Carry out the operations such as follow-up modulation, MIMO space division multiplexing.Purpose is to meet system to the rate of information throughput with communication quality (by mistake Code check) on the premise of, reduce system emission power as far as possible；Reduce the complexity performing bit loading algorithm simultaneously.

Claims (1)

1. MIMO-OFDM systematic bits distribution method based on delayed channel status information, it is characterised in that including:

Transmitting terminal, according to the channel condition information of time delay, estimates current actual channel；

The channel condition information of described time delay is transmitting terminal comprises N by sending from receiving terminal of obtaining of feedback channel_CIndividual subcarrier Channel condition information H^f(n), compared with channel H (n) when occurring with bit transfer, the channel condition information H of time delay^fN () is to have The channel condition information that certain time is delayed；

The channel condition information H of the time delay that described transmitting terminal obtains^fCorrelation coefficient ρ is there is between (n) and present channel H (n)

ρ=J₀(2πf_DT_delay)；

Wherein: J₀() first kind Oth order Bessel function, T_delayFor feedback delay, f_DFor Doppler frequency displacement；

Described transmitting terminal estimates present channel according to the channel condition information of time delayParticularly as follows:

$\hat{H}\left(n\right)={\mathrm{\ρH}}^f\left(n\right)+\mathrm{\Ξ}\left(n\right),n=0,1,...,N_C-1$

Wherein: Ξ (n) is the random matrix of estimation difference, multiple Gauss distribution is obeyed It it is channel matrix In the variance of estimaion error of each element, It it is the average power gain of wireless link；N_TIt it is transmitting terminal sky Line quantity, N_RIt it is receiving terminal antenna amount；It is N_T×N_R0 matrix；It is N_TThe unit matrix on rank；

According to the currently practical channel estimated and error rate BER requirement, calculate the constellation distance ginseng of each MIMO spatial sub-channel Number

The constellation distance parameter of each spatial sub-channel of described calculatingIncluding:

Respectively to channel matrixWith H^fN () carries out singular value decomposition, and H^f(n), H (n) withIt is all N_T×N_RMatrix, Then singular value decomposition is

$\begin{array}{c}{\mathrm{\ρH}}^f\left(n\right)=\stackrel{\‾}{U}\left(n\right)\stackrel{\‾}{\mathrm{\Λ}}\left(n\right){\stackrel{\‾}{V}}^H\left(n\right)\\ ={\mathrm{\Σ}}_{i=1}^{M_S}{\stackrel{\‾}{u}}_i\left(n\right){\stackrel{\‾}{\mathrm{\λ}}}_i\left(n\right){\stackrel{\‾}{v}}_i^H\left(n\right)\end{array},$

Calculate least square Euclidean distance

$d_{i,E}^2\left(n\right)=4g\left(b_i\right(n\left)\right)P_i\left(n\right)T_s;$

Normalized squared euclidean distance parameter

$\begin{array}{c}{d}_i^2\left(n\right)=d_{i,E}^2\left(n\right)/\left(4T_s\right)\\ =g\left(b_i\left(n\right)\right)P_i\left(n\right)\end{array};$

Determine the error rate BER of approximation on the channel i of i-th subspace_i(n)

${\mathrm{BER}}_i\left(n\right)\≈0.2\·\exp (-{\mathrm{\λ}}_i^2(n\left)d_i^2\right(n)/{\mathrm{\σ}}^2)$

Determine the average error rate on the channel of i-th subspace

${\stackrel{\‾}{BER}}_i\left(n\right)\≈0.2{\left(\frac{1}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2}\right)}^{N_R}\·\exp (-\frac{{\stackrel{\‾}{\mathrm{\λ}}}_i^2\left(n\right)d_i^2\left(n\right)/{\mathrm{\σ}}^2}{1+d_i^2\left(n\right){\mathrm{\σ}}_{\mathrm{\ϵ}}^2/{\mathrm{\σ}}^2})$

Target error rate in given i-th subchannelReach the minimum needed for target error rateCan be from Above-mentionedTry to achieve；

Wherein: n represents subcarrier sequence number n=1,2 ... N_C；I represents the sequence number of spatial sub-channel on subcarrier n；For unusual Value,For the average of singular value, andForStochastic variable；N_TAnd N_RRepresent respectively to launch and join respectively with receiving terminal Put the number of antenna；M_SIt is H (n) the spatial sub-channel number that carries out singular value decomposition generation, M_S=min (N_T,N_R)；It is to ρ H respectively^fN () carries out the left singular matrix of generation during singular value decomposition, singular value matrix, the right side very Different matrix；It is to ρ H respectively^fN () carries out the left singular vector of generation, right singular vector during singular value decomposition；g B () is the function about bit number b,b_i(n)、P_iN () is on the n-th subcarrier respectively The bit number of i-th spatial sub-channel loading and power, T_SIt is to remove the OFDM symbol cycle after Cyclic Prefix；

According to the feature of MIMO-OFDM channel, all spatial sub-channels are divided into two groups, and determine bit number that two components join Distribution；

Described all spatial sub-channels are divided into the method for two groups and include:

Spatial sub-channel 1 and spatial sub-channel 2 on each OFDM carrier wave are subdivided into first group, and other subchannels are subdivided into second Group；

If only two spatial sub-channels on each OFDM carrier wave, then subchannel 1 is subdivided into first group,

Subchannel 2 is subdivided into second group；

The distribution of the bit number that described two components are joined includes: b_maxWith b_max-2；b_max-2 and b_max-4；

b_maxIt it is bit number to be determined for even number；

The determination of the design parameter of described bit number distribution includes:

A. b is made_max=4；

B. first group of whole subchannel loads b_max-2 bits, second group all loads b_max-4 bits；

If c. in step b, gained bit number less than 0, is then taken as 0 bit, total speed R that two groups of channels reach_total；

If d. R_total> total number of bits R transmitted_need, enter next step e；Otherwise b_max=b_max+ 2, return b；

e.b_max=b_max-2；

Then: the bit number that two components are joined is respectively b_maxWith b_max-2 and b_max-2 and b_max-4；

If negative value occurs in above-mentioned bit number, then it is taken as 0 bit；

Bit number distribution, the total rate requirement of system determined by Yi Ju, by total for system rate-allocation to two groups, and ratio is often organized in distribution Special distributed constant；

In described group, the method for the bit number that the calculating of each spatial sub-channel is distributed includes:

A. first group of subchannel is made all to load b_maxThe speed that-2 bits are reached is R_a, second group of subchannel all loads b_maxThe speed that-4 bits are reached is R_b, then remaining bits is R_rem=R_need-R_a-R_b；

B. it is the first component proportion spy number R₁=R_a+R_rem/ 2, second component joins bit number R₂=R_b+R_rem/2；

According to each group of speed distributed and the constellation distance parameter of spatial sub-channel, calculate for each spatial sub-channel in group and divide The bit number joined and launch power accordingly；

In described group, each spatial sub-channel includes according to the corresponding method launching power of distribution:

Setting pth (p=1,2) is organized interior two bit numbers and is respectively b_upWith b_low, and total bit number that this component is joined is R_p；

To own in groupAscending order arranges, and forms array

To (R_p-b_low)/2 round up, and obtain Integer N₁, then front N in array₁IndividualCorresponding subchannel all loads b_upRatio Special；Residue subchannel all loads b_lowBit；

Bit number according to loading in subchannel obtains corresponding power demand factor F, is launched power accordingly

The transmitting power of all subchannels is sued for peace, just obtains the transmitting power of system,

Wherein: m is this element sequence number in array d, i is the spatial sub-channel sequence number at its place, and j, k, l are that its place carries The sequence number of ripple.