CN101488934B - Power allocation method for modulation constrained system - Google Patents
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Abstract
The invention discloses a power splitting method for modulating a limited system, including the following steps: a. the maximum transmission speed of each sub-channel is determined according to the maximum modulation coding manner; b. a sending terminal arranges each sub-channel according to down channel eigenvalue matrix so that the strongest sub-channel is used as the current sub-channel and the system gross power is used as the current splitting power; c. the sending terminal counts the original power of the current sub-channel and the saturation power of the current sub-channel so that the actual transmission power of the sub-channel is determined according to the minimum value of original power and saturation power; d. the sending terminal uses the difference of the current splittingpower and the actual transmission power of the current sub-channel as new current splitting power, and whether the current sub-channel is a subweak sub-channel is judged; if so, the current splittingpower is distributed to the weakest sub-channel and the process is finished; or, the next sub-channel is used as the current sub-channel and the step c is returned back. The application of the methodin the invention can guarantee system volume and meanwhile save system power.
Description
Technical field
The present invention relates to the technology of multiple-input, multiple-output (MIMO)-OFDM (OFDM) system, particularly a kind of power distribution method of modulation constrained MIMO-OFDM system.
Background technology
Multiple-input, multiple-output (MIMO) system is sending and receiving terminal uses the communication system of many antennas simultaneously, the space multiplexing technique of mimo system is the different data flow of emission on different antennas, space multiplexing technique can improve capability of communication system and spectrum efficiency exponentially under the situation that does not increase bandwidth, really embodied the essence that the mimo system capacity improves.
By channel is decomposed, we can become the several separate parallel sub-channels to the channel equivalence, transmit information independently by these parallel spatial subchannels.The separate space channel can characterize with the order r of spatial channel matrix, and the independent data stream that mimo system can transmit simultaneously can not be greater than space channel order r, and r≤min (M
t, M
r), wherein, M
tBe transmitting antenna number, M
rBe the reception antenna number.Each independently transmitting data stream all be regarded as one " empty antenna ", also be mapped to simultaneously a subchannel.
In the present communication system, owing to adopt Adaptive Modulation and Coding (AMC) technology, transmitting terminal can be adjusted the modulating-coding strategy according to the channel quality indication (CQI) of receiving terminal feedback, determines the modulation coding mode that each subchannel adopts, thereby obtains the big capacity of trying one's best.Usually, the CQI of subchannel is big more, can adopt the modulating-coding strategy of two-forty more, obtains high more subchannel capacities.And if the power that a certain subchannel distributes is many more, the CQI that obtains is big more, therefore transmitting terminal just can adopt higher modulating-coding strategy, obtain higher subchannel capacities, simultaneously, the error rate of this subchannel parameters such as (BER) also can change thereupon, thereby causes CQI to change, and influences the modulating-coding strategy again; Vice versa.As seen, by adjusting the watt level of each subchannel, just can obtain the different subchannel capacities and the error rate, and under the certain condition of total transmitting power, the total power system capacity and the error rate also change along with the variation of power division, therefore by adjusting sub-channel power, can realize the purpose of the Adjustment System capacity and the error rate.
The assigning process of concrete each sub-channel power can be realized in precoding.In the precoding technique of non-code book, the constraints that obtains as pre-coding matrix with certain optimization aim (such as maximum capacity or minimize overall mean square error), thereby carry out power division according to optimum target, obtain the pre-coding matrix of certain power allocation scheme correspondence.Send the process of pre-coding matrix on the signal times, just each data flow has been carried out power division.
Existing power allocation scheme mainly contains maximization information rate (capacity), minimizes overall mean square error (MMSE), waits several schemes of gain channel decomposing.Wherein, wait gain channel decomposing technology to comprise GMD (Geometric Mean Decomposition) and UCD (Uniform Channel Decomposition) etc.
But because the characteristics of the present and following communication system are exigent transmission rate (power system capacities), therefore maximizing information rate is the main power distribution strategies of studying at present.Obtained the waterflood project of power division as target, promptly more power division in the bigger better subchannel of gain, make it to obtain higher speed, and more weak subchannel is given less power, thereby improves the transmission rate of whole system.Below the power distribution method of water flooding regime is done and briefly introduced.
Suppose that a mimo system has M transmitting antenna, N reception antenna, the order of channel matrix is B.Adopt water-filling algorithm that the idiographic flow that all B subchannel carries out power division is comprised:
Power division matrix Φ
fDefinite mode be:
σ wherein
n 2Be power noise ,+expression is non-negative, promptly all negative values all value be 0; Φ
fBe the full rank diagonal matrix, square Φ of its diagonal element
F, i 2Be the watt level that i sub-channel allocation arrives, the power that all subchannels distribute and equal gross power, i.e. trace (Φ
f 2)=p, wherein, trace () is for asking the mark operation.
Particularly, the computational process of formula (1) is, at first the contrary Λ of calculated characteristics value matrix Λ
-1, then with each element and the σ of this inverse matrix
n 2Multiplying each other obtains product matrix, utilizes μ again
-1/2Deduct each element in the product matrix, the difference that obtains constituted matrix of consequence as the element of relevant position, again with the negative value in this matrix of consequence all value be 0, again each element in the matrix is asked power 1/2 time, promptly obtain Φ
f
Wherein, pre-coding matrix F=V Φ
fWith this pre-coding matrix relevant detection matrix
In above-mentioned two formulas, V is not for adopting the pre-coding matrix of power division, Φ
gFor with Φ
fCorresponding received power matrix.
After utilizing aforesaid way to carry out power division, system's heap(ed) capacity that can reach in theory is C
Opt:
Wherein, λ
iIt is the characteristic value of i subchannel.As seen, carry out power division by the way and can obtain theoretic heap(ed) capacity, the theoretical transmission rate than the hadron channel that this algorithm obtains is often very big.But because the restriction of modulation constellation, the highest modulation strategy can only reach 64QAM, and code rate can not surpass 1, and this has just limited the speed of transfer of data.Even adopt the highest modulating-coding strategy, getable peak transfer rate also is certain.Special under the condition of high s/n ratio, the modulation strategy of the transmission rate request of strong channel often reaches 128QAM even higher, and this is beyond one's reach under present circumstances.If give a lot of power of strong channel allocation according to water-filling algorithm, possible subchannel reaches the highest transmission rate for a long time, and therefore the raising that can not bring transmission rate will cause power dissipation.Here it is, and present modulation constrained system is used a drawback of water-filling algorithm, also is the problem that other power division modes may run into.
Simultaneously, because the performance number that obtains through power division is continuous, employed to change into the modulating-coding strategy (MCS) that obtains after the transmission rate by power be continuous with regard to requiring transmit power allocations value in real system and subchannel for this.But disperse between the planisphere size of different modulating exponent number, transmit power allocations also is the result who obtains after quantizing, if a performance number can only adopt lower modulation coding mode corresponding between two kinds of modulation coding modes, power loss will be arranged.This is the common drawback of present power distribution algorithm.
Summary of the invention
In view of this, the invention provides a kind of power distribution method of modulation constrained system, can guarantee power system capacity, save system power simultaneously.
For achieving the above object, the present invention adopts following technical scheme:
A kind of power distribution method of modulation constrained system comprises:
A, according to the high modulation coded system that each subchannel in the system can reach, determine the peak transfer rate of described each subchannel;
B, transmitting terminal according in the eigenvalue matrix of down channel with descending each subchannel of sequence arrangement of each subchannel characteristic of correspondence value, and with the subchannel of characteristic value maximum as current subchannel, with system's gross power as current distribution power;
C, transmitting terminal are according to the eigenvalue matrix and the current distribution power of described down channel, calculate the original power of current subchannel, determine the saturation power of current subchannel according to the peak transfer rate of current subchannel, and determine the actual transmission power of this subchannel according to the minimum value in original power and the saturation power;
D, transmitting terminal with the difference of the actual transmission power of current distribution power and current subchannel as new current distribution power, and whether the characteristic value of judging current subchannel is time little subchannel, if, then give minimum subchannel with current distribution power division, and process ends; Otherwise next subchannel as current subchannel, and is returned step c.
Preferably, describedly determine that according to the minimum value in original power and the saturation power actual transmission power of this subchannel is: with the actual transmission power of the minimum value in original power and the saturation power as this subchannel;
Perhaps, when original power during more than or equal to saturation power, with the actual transmission power of saturation power, when original power during, with the power of the maximum modulation coding strategy correspondence in the original power scope actual transmission power as this subchannel less than saturation power as this subchannel.
Preferably, described step a is:
In advance by emulation, determine modulation coding mode and channel circumstance when each subchannel capacities reaches capacity under the residing environment in base station, the high modulation coded system that the modulation coding mode when described each subchannel capacities is reached capacity can reach as described each subchannel;
At each subchannel, water-filling algorithm when this subchannel capacities of emulation reaches capacity under the channel circumstance, the power that distributes according to this subchannel characteristic of correspondence value in the noise power of this subchannel that measures, the channel matrix and for this subchannel calculates the peak transfer rate of this subchannel.
Preferably, the peak transfer rate of described this subchannel of calculating is:
Wherein, R
Lim, iBe the peak transfer rate of i subchannel,
Be the saturation power of i subchannel correspondence, λ
iBe i subchannel characteristic of correspondence value in the channel matrix,
It is the noise power of i subchannel.
Preferably, at each subchannel, the water-filling algorithm when this subchannel capacities is reached capacity under the channel circumstance carries out repeatedly emulation, and calculates the average of this subchannel peak transfer rate that each emulation obtains;
Determine the saturation power of described current subchannel among the step c according to the average of current subchannel peak transfer rate.
Preferably, the eigenvalue matrix of described down channel is, the down channel matrix that receiving terminal obtains channel estimating carries out SVD and decomposes and obtain and feed back to transmitting terminal by feedback channel; Perhaps, according to the up-downgoing reciprocity of TDD channel, transmitting terminal carries out SVD to the up channel matrix of estimating to obtain and decomposes, with the eigenvalue matrix of the up channel that the obtains eigenvalue matrix as described down channel.
Preferably, among the step c according to water-filling algorithm, eigenvalue matrix and current distribution power according to described down channel, calculate current subchannel and according in the eigenvalue matrix of down channel with the power division matrix of descending all subchannels of sequence arrangement after current subchannel of each subchannel characteristic of correspondence value, with the original power of power corresponding in the described power division matrix as current subchannel with current subchannel.
Preferably, the current subchannel of described calculating and according in the eigenvalue matrix of down channel with the power division matrix Φ of descending all subchannels of sequence arrangement after current subchannel of each subchannel characteristic of correspondence value
fComprise:
Eigenvalue matrix according to described down channel, determine current subchannel and according to being arranged in all subchannel characteristic of correspondence values after the current subchannel with the descending sequence arrangement of each subchannel characteristic of correspondence value in the eigenvalue matrix of down channel, and utilize above-mentioned characteristic value to constitute current eigenvalue matrix Λ ';
According to
Calculate described power division matrix Φ
f, wherein, σ
n 2Be the noise power of down channel, ()
+Expression to all negative values all value be 0.
Preferably, described peak transfer rate R according to current subchannel i
Lim, iDetermine the saturation power φ of current subchannel i
F, i 2*For: according to
Determine saturation power φ
F, i 2*, wherein, λ
iFor in the eigenvalue matrix of described down channel with current subchannel i characteristic of correspondence value, σ
n 2Noise power for down channel.
Preferably, the noise power of described down channel is that receiving terminal estimates to obtain and feed back to transmitting terminal;
Perhaps, according to the up-downgoing reciprocity of TDD channel, transmitting terminal is with the noise power of the up channel estimating the to obtain noise power as described down channel.
As seen from the above technical solution, among the present invention, the high modulation coded system that can reach according to each subchannel in the system is at first determined the peak transfer rate of each subchannel.Then, according to the eigenvalue matrix of down channel, with each subchannel according to channel strength by strong to weak sequence arrangement.From the strongest subchannel, be followed successively by each subchannel and distribute power.When carrying out the power division of arbitrary subchannel, with the difference between system's gross power and the power that dispensed as current distribution power, eigenvalue matrix and current distribution power according to down channel, calculate the power of this subchannel according to existing power allocation scheme, and calculate saturation power according to the peak transfer rate of this subchannel, to determine the actual transmission power of this subchannel according to the minimum value in power that calculates according to power allocation scheme and the saturation power, thereby guarantee to make subchannel capacities big as far as possible on the one hand, avoid on the other hand saving system power into subchannel distributes unnecessary power.After this, remaining power is carried out power division to the subchannel of the unallocated power of remainder.Up to being assigned to intensity time weak subchannel, remaining power is all distributed to the most weak subchannel of intensity.After the application aforesaid way carries out power division, can guarantee power system capacity, save system power again.
Description of drawings
Fig. 1 is the overview flow chart of the power distribution method of modulation constrained system among the present invention.
Fig. 2 is a system block diagram of using power distribution method of the present invention in the MIMO-OFDM system.
Fig. 3 utilizes power distribution method of the present invention to carry out the transfer of data particular flow sheet of precoding.
Fig. 4 is that the performance of multiple power distribution method compares schematic diagram.
Embodiment
For making purpose of the present invention, technological means and advantage clearer, below in conjunction with accompanying drawing the present invention is done to describe in further detail.
Basic thought of the present invention is: when carrying out power division, on the one hand utilize existing power distribution algorithm to carry out power division, according to high modulation coded system, the maximum power of each subchannel is distributed in restriction, thereby avoids power dissipation on the other hand.
Fig. 1 is the overview flow chart of the power distribution method of modulation constrained system among the present invention.As shown in Figure 1, this method comprises:
In this step, the power of distributing to this subchannel of the original power of current subchannel for determining according to existing power allocation scheme, for example, water-filling algorithm etc.
By the way, begin to distribute power from the strongest subchannel, and the minimum value in the saturation power of the distribution power that will obtain according to existing power allocation scheme and this subchannel is used to distribute to the more weak subchannel of follow-up intensity as the transmitted power of distributing to this subchannel with remaining transmitted power.Can guarantee that subchannel capacities reaches current maximum, avoids power dissipation on the other hand like this, on the one hand.
Be example to use method of the present invention in the MIMO-OFDM system below, by specific embodiment explanation the specific embodiment of the present invention, and in this process, the existing power allocation scheme of application is a water-filling algorithm.
Fig. 2 is a system block diagram of using power distribution method of the present invention in the MIMO-OFDM system.As shown in Figure 2, M transmitting antenna arranged in this system, N reception antenna, the order of channel matrix is B.Fig. 3 utilizes power distribution method of the present invention to carry out the transfer of data particular flow sheet of precoding.As shown in Figure 3, this method comprises:
This step preferably realizes according to the emulation testing process before system's operation.Concrete operations can be as follows:
A, by emulation, (for example determine the residing typical environment in base station, urban environment, rural environment etc.) modulation coding mode and channel circumstance when down each subchannel capacities reaches capacity, the high modulation coded system that the modulation coding mode when described each subchannel capacities is reached capacity can reach as each subchannel.Wherein, the relation curve of the signal to noise ratio (snr) of emulation acquisition subchannel and the actual transfer rate of subchannel, some when on behalf of subchannel capacities, the point when this relation curve begins to tend to be steady reach capacity, the high modulation coded system that the modulation system of this moment is that subchannel can reach, signal to noise ratio at this moment are the channel circumstance of subchannel capacities when reaching capacity.
B, at each subchannel, water-filling algorithm when this subchannel capacities of emulation reaches capacity under the channel circumstance, the power that distributes according to this subchannel characteristic of correspondence value in the noise power of this subchannel that measures, the channel matrix and for this subchannel, calculate the peak transfer rate of this subchannel, and with the saturation power of the described power that distributes for this subchannel as this subchannel correspondence.Wherein, for arbitrary subchannel i, under the signal to noise ratio condition the when subchannel capacities that obtains in the corresponding A process is saturated, the emulation water-filling algorithm can measure the noise power σ of this subchannel
n 2, this subchannel characteristic of correspondence value λ
iWith the power φ that distributes for this subchannel according to water-filling algorithm
F, i 2, and according to formula
Determine the peak transfer rate of this subchannel.
More accurate for guaranteeing the peak transfer rate that emulation obtains, preferably, execution in step B repeatedly obtains a plurality of peak transfer rates of arbitrary subchannel through emulation repeatedly, these peak transfer rate values are averaged, with the peak transfer rate of this average as this subchannel.
Preferably, the peak transfer rate with each definite in the manner described above subchannel is configured in transmitting terminal.
Operation in this step is identical with existing implementation, just repeats no more here.
In this step, transmitting terminal determines that the mode of down channel eigenvalue matrix can have two kinds:
One, receiving terminal down channel matrix that channel estimating is obtained carries out SVD and decomposes the eigenvalue matrix that obtains down channel, and by feedback channel the eigenvalue matrix Λ of this down channel is fed back to transmitting terminal;
Two, according to the up-downgoing reciprocity of TDD channel, transmitting terminal estimates to obtain the up channel matrix, and this up channel matrix carried out the eigenvalue matrix that SVD decomposes the up channel obtain, and with the eigenvalue matrix of this up channel eigenvalue matrix Λ as down channel; Under this mode, do not need receiving terminal feedback characteristic value matrix.
In eigenvalue matrix, the descending order of characteristic value be corresponding subchannel intensity by strong to weak order, therefore in this step, the mode of arranging each subchannel is: according in the eigenvalue matrix of down channel with descending each subchannel of sequence arrangement of each subchannel characteristic of correspondence value.
In this step, calculate the mode of the original power of current subchannel according to water-filling algorithm, identical with existing water-filling algorithm implementation, promptly utilize the step 2 in the background technology to determine power division matrix Φ
f, again with square the original power of diagonal entry corresponding in this power division matrix with current subchannel as current subchannel.
Wherein, the eigenvalue matrix of using in the water-filling algorithm is current eigenvalue matrix Λ ', concrete obtain manner is: according to the eigenvalue matrix Λ of down channel, determine current subchannel and according to by strong all subchannel characteristic of correspondence values after weak ordering is arranged in current subchannel, and utilize above-mentioned characteristic value to constitute current eigenvalue matrix Λ '.And, carry out according to current eigenvalue matrix Λ ' and current distribution power when determining Lagrangian coefficient μ in the water-filling algorithm.
In this step, according to functional relation
Determine the saturation power φ of current subchannel i
F, i 2*, wherein, R
Lim, iBe the peak transfer rate of current subchannel i definite in the step 301, λ
iFor in the eigenvalue matrix of down channel with current subchannel i characteristic of correspondence value, σ
n 2Be the noise power of down channel, can estimate and feed back to transmitting terminal by receiving terminal, also can be by the reciprocity of transmitting terminal according to the up-downgoing channel, with the up channel noise power estimating to obtain noise power as down channel.
If the saturation power of current subchannel is less than original power, i.e. φ
2 F, k *＜φ
2 F, k, the high modulation coded system that the modulation coding mode that shows the original power correspondence that obtains according to water-filling algorithm has been higher than that this subchannel can reach, at this moment, even be that this subchannel distributes φ
2 F, kPower can not reach the subchannel capacities that water-filling algorithm is expected, can cause the waste of system power, and therefore, under this situation, the power that distributes for current subchannel is φ
2 F, k *, unnecessary power is left on the more weak subchannel of back intensity, promptly B-k remaining subchannel used
Power carry out water filling again and distribute;
If the saturation power of current subchannel is more than or equal to original power, i.e. φ
2 F, k *〉=φ
2 F, kThe high modulation coded system that the modulation coding mode that shows the original power correspondence that obtains according to water-filling algorithm is less than or equal to that this subchannel can reach, at this moment, this subchannel can reach the subchannel capacities of water-filling algorithm expection, therefore, the power that distributes for current subchannel is φ
2 F, k
In a word, with the actual transmission power of the minimum value in saturation power and the original power as current subchannel, thereby make current subchannel can either guarantee the big subchannel capacities of trying one's best, system power simultaneously avoids waste.
This step is upgraded current distribution power, and concrete update mode is: as new current distribution power, is that follow-up subchannel carry out power division thereby utilize remaining system power with the difference of the actual transmission power of current distribution power and current subchannel.
In power distribution method of the present invention, after determining that according to account form all subchannels except that weakon channel all assign, do not need to calculate again the distribution power of weakon channel, but directly remaining system power is distributed to weakon channel, therefore, here need to judge whether to be inferior weak subchannel, thereby judge whether that needing to repeat above-mentioned steps 305 calculates transmitted power.
Step 308 is given the most weak subchannel with current distribution power division.
Step 309 constitutes the power division matrix with the actual transmission power of all subchannels of determining, and multiplies each other with the pre-coding matrix that does not adopt power division and to obtain actual pre-coding matrix.
Step 310 utilizes actual pre-coding matrix that B data stream is carried out precoding, obtains the emission symbols streams corresponding to M transmitting antenna, launches from transmitting antenna.
Precoding is equivalent to data streams be multiply by pre-coding matrix, thereby obtain the symbols streams of antenna emission, be S=FX, wherein X is that B * k dimension sends dfd matrix, F is the pre-coding matrix of M * B dimension, S is the transmission symbols streams matrix of M * k dimension, and its each row is corresponding to the transmission data of an antenna.
When carrying out input, can be undertaken by separating pre-coding matrix G, also can not need to calculate and separate pre-coding matrix G, and as long as transmitting terminal just inserts pilot tone before carrying out precoding processing, precoding process and channel procedure are merged into an equivalent channel, go out equivalent channel HF at receiving terminal according to the pilot tone direct estimation and detect.
Applied power division mode of the present invention in the above-mentioned whole method for transmitting signals has not only guaranteed the information rate of strong channel, and can be unnecessary power division to the weakon channel, thereby increases the transmission rate of unsaturation channel.Though can't reach theoretical optimization capacity, in the modulation constrained system, this allocative decision remains the capacity optimum.The channel capacity that obtains thus is: it is saturated to suppose to have r subchannel to reach capacity,
φ wherein
F, i 2Use exactly
Power B-r remaining subchannel carried out water-filling algorithm obtain power division.
The power distribution method of the invention described above can also remedy in the existing power distribution method because the loss that discrete order of modulation is brought.Particularly, in step 305, after calculating original power and saturation power, when original power during more than or equal to saturation power, with the actual transmission power of saturation power as this subchannel, when original power during, with the power of the maximum modulation coding strategy correspondence in the original power scope actual transmission power as this subchannel less than saturation power.That is to say that the power that each subchannel is distributed only corresponds to a certain fixed modulation coding strategy, and can not fall between two kinds of strategies, the distribution of channel prevented power dissipation after therefore unnecessary power just can be used for.
At power distribution method of the present invention and existing multiple power distribution method, carried out performance comparison by emulation.Fig. 4 is the result schematic diagram of performance comparison.Concrete simulated environment is: under the big spacing aerial array that 42 are received, and the simulation result when the URBANMACRO environment sends two data flow, subchannel number is 2.
As shown in Figure 4, the graph of a relation of curve 401 signal to noise ratio and throughput when adopting power distribution method of the present invention; The graph of a relation of signal to noise ratio and throughput when curve 402 carries out power division for adopting the MMSE strategy; The graph of a relation of signal to noise ratio and throughput when curve 403 carries out power division for adopting inactivity (constant power) strategy; The graph of a relation of signal to noise ratio and throughput when curve 404 carries out power division for adopting water-filling algorithm.
By above-mentioned simulation result as seen, when (SNR＜14db), the result of power distribution method of the present invention and water-filling algorithm is consistent, but all than the throughput of system height of MMSE and constant power allocation algorithm under the low signal-to-noise ratio during strong channel unsaturation; (SNR＞14db), power distribution strategies of the present invention can obtain maximum throughput when strong channel reaches capacity.If send more multiple data stream, the subchannel that can allocate is more, and the advantage of iteration water-filling algorithm also can better embody.
Being preferred embodiment of the present invention only below, is not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. the power distribution method of a modulation constrained system is characterized in that, this method comprises:
A, according to the high modulation coded system that each subchannel in the system can reach, determine the peak transfer rate of described each subchannel;
B, transmitting terminal according in the eigenvalue matrix of down channel with descending each subchannel of sequence arrangement of each subchannel characteristic of correspondence value, and with the subchannel of characteristic value maximum as current subchannel, with system's gross power as current distribution power;
C, transmitting terminal are according to the eigenvalue matrix and the current distribution power of described down channel, calculate the original power of current subchannel, determine the saturation power of current subchannel according to the peak transfer rate of current subchannel, and determine the actual transmission power of this subchannel according to the minimum value in original power and the saturation power;
D, transmitting terminal with the difference of the actual transmission power of current distribution power and current subchannel as new current distribution power, and whether the characteristic value of judging current subchannel is time little subchannel, if, then current distribution power division is given the subchannel of characteristic value minimum, and process ends; Otherwise next subchannel as current subchannel, and is returned step c.
2. method according to claim 1, it is characterized in that, describedly determine that according to the minimum value in original power and the saturation power actual transmission power of this subchannel is: with the actual transmission power of the minimum value in original power and the saturation power as this subchannel;
Perhaps, when original power during more than or equal to saturation power, with the actual transmission power of saturation power, when original power during, with the power of the maximum modulation coding strategy correspondence in the original power scope actual transmission power as this subchannel less than saturation power as this subchannel.
3. method according to claim 1 is characterized in that, described step a is:
In advance by emulation, determine modulation coding mode and channel circumstance when each subchannel capacities reaches capacity under the residing environment in base station, the high modulation coded system that the modulation coding mode when described each subchannel capacities is reached capacity can reach as described each subchannel;
At each subchannel, water-filling algorithm when this subchannel capacities of emulation reaches capacity under the channel circumstance, the power that distributes according to this subchannel characteristic of correspondence value in the noise power of this subchannel that measures, the channel matrix and for this subchannel calculates the peak transfer rate of this subchannel.
4. method according to claim 3 is characterized in that, the peak transfer rate of described this subchannel of calculating is:
Wherein, R
Lim, iBe the peak transfer rate of i subchannel, φ
F, i 2Be the saturation power of i subchannel correspondence, λ
iBe i subchannel characteristic of correspondence value in the channel matrix,
It is the noise power of i subchannel.
5. method according to claim 3 is characterized in that, at each subchannel, the water-filling algorithm when this subchannel capacities is reached capacity under the channel circumstance carries out repeatedly emulation, and calculates the average of this subchannel peak transfer rate that each emulation obtains;
Determine the saturation power of described current subchannel among the step c according to the average of current subchannel peak transfer rate.
6. method according to claim 1 is characterized in that, the eigenvalue matrix of described down channel is, the down channel matrix that receiving terminal obtains channel estimating carries out SVD and decomposes and obtain and feed back to transmitting terminal by feedback channel; Perhaps, according to the up-downgoing reciprocity of TDD channel, transmitting terminal carries out SVD to the up channel matrix of estimating to obtain and decomposes, with the eigenvalue matrix of the up channel that the obtains eigenvalue matrix as described down channel.
7. method according to claim 1, it is characterized in that, among the step c according to water-filling algorithm, eigenvalue matrix and current distribution power according to described down channel, calculate current subchannel and according in the eigenvalue matrix of down channel with the power division matrix of descending all subchannels of sequence arrangement after current subchannel of each subchannel characteristic of correspondence value, with the original power of power corresponding in the described power division matrix as current subchannel with current subchannel.
8. method according to claim 7, it is characterized in that, the current subchannel of described calculating and according in the eigenvalue matrix of down channel with the power division matrix Ф of descending all subchannels of sequence arrangement after current subchannel of each subchannel characteristic of correspondence value
fComprise:
Eigenvalue matrix according to described down channel, determine current subchannel and according in the eigenvalue matrix of down channel with descending sequence arrangement all the subchannel characteristic of correspondence values after current subchannel of each subchannel characteristic of correspondence value, and utilize above-mentioned characteristic value to constitute current eigenvalue matrix Λ ';
According to
Calculate described power division matrix Φ
f, wherein,
Be the noise power of down channel, ()
+Expression to all negative values all value be 0.
9. method according to claim 1 is characterized in that, described peak transfer rate R according to current subchannel i
Lim, iDetermine the saturation power of current subchannel i
For: according to
Determine saturation power
Wherein, λ
iFor in the eigenvalue matrix of described down channel with current subchannel i characteristic of correspondence value,
Noise power for down channel.
10. according to Claim 8 or 9 described methods, it is characterized in that the noise power of described down channel is that receiving terminal estimates to obtain and feed back to transmitting terminal;
Perhaps, according to the up-downgoing reciprocity of TDD channel, transmitting terminal is with the noise power of the up channel estimating the to obtain noise power as described down channel.
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