CN101483502B - Adaptive transmission method suitable for hybrid modulation mode - Google Patents

Abstract

The present invention provides a self-adapting transmission method which is suitable for hybrid modulating mode. In the method, the power of transmitting signal is optimized and allocated for each allocating unit according to the modulating mode adopted by each allocating unit, the bit error rate requirement of system and the transmission state of channel at different time. Furthermore the signal is transmitted according to the modulating mode and power allocating result. The method of the invention furthest reduces the total power of transmission signal of system when the bit error rate requirement of system is ensured to be obtained by the system. Each allocating unit in the system can adopt a random modulating mode selected from the binary system phase shift keying, multi-ary quadrature amplitude modulation, multi-ary phase shaft keying. The method of the invention has the advantages of high flexibility, high suitability, low complexity and suitability for the practical application.

Description

A kind of adaptive transmission method that is applicable to compound modulation

Technical field

The present invention is a kind of adaptive transmission method, be used in multicarrier system or multiaerial system, after given each allocation units (as subchannel, antenna etc.) modulation system used, for each allocation units in system distribute the power of transmitted signal, belong to the adaptive modulation technology field in radio communication.

Background technology

Multicarrier system and multiaerial system are the cores of current and following broadband high-speed communication system.Multi-transceiver technology is (as OrthogonalFrequency Division Multiplexing, OFDM, OFDM) transmission channel in whole broadband is divided into to the subchannel of a plurality of arrowbands, and carry out the parallel transmission data by these subchannels, can effectively resist frequency selective fading, reduction system complexity, raising system spectrum utilance and the transmission rate of multipath channel.Multi-antenna technology (Multiple-Input Multiple-Output, MIMO, multiple-input, multiple-output) passes through parallel transmission data on a plurality of antennas, and, to being encoded between the data of transmitting on each antenna, can greatly improve the availability of frequency spectrum of system.The combination of these two kinds of technology is also current and the core technology of future broadband wireless communication system.

Adaptive modulation technology is not channel transfer characteristic in the same time of a kind of basis, for distribution unit such as the subchannel in system or antennas, selects suitable modulation system and transmitted power, carries out the technology of signal transmission.While adopting adaptive modulation technology, the adaptive adjustment along with the variation of channel status of the modulation system of each allocation units or transmitted signal power.Adaptive modulation technology can effectively utilize the frequency of multipath time varying channel/time selective fading feature, improves the availability of frequency spectrum or the power utilization of system.Adaptive modulation technology is applicable to being applied in multicarrier system and multiaerial system very much.In multicarrier system, every sub-channels is " allocation units " that need to carry out modulation system and power division, in addition a plurality of groups of subchannels are combined, form one " equivalent subchannel ", be also mode commonly used while in multicarrier system, adopting adaptive modulation technology, each " equivalent subchannel " also can be regarded as one " allocation units ".In multiaerial system, each dual-mode antenna between " equivalent transmission channel " be " allocation units " that carry out adaptive modulation system and power division.Allocation units can be also other forms, as channel of different time-gap, different user etc.Every needs carry out modulation system or power division physically, sky/time in logic/frequency Resource Block, can regard " allocation units " in the Adaptive Modulation skill as.

According to the difference of constraints and optimization aim, adaptive modulation technology can roughly be divided three classes: have plenty of under total transmitting power and the certain condition of error rate of system, it is maximum that the system transmission rate of making reaches; Have plenty of under system transmission rate and the certain condition of the error rate, make needed total transmitting power minimum; Have plenty of under the total transmitting power of system and the certain condition of system transmission rate, make the error rate of system minimum while meeting certain error rate (or signal to noise ratio surplus maximum), etc.

A kind of adaptive transmission method that is applicable to compound modulation proposed by the invention, its optimization aim is under the constraints of the modulation system of given each allocation units and the aims of systems error rate, makes the transmitting power of system minimum.The modulation system that wherein each allocation units adopt, can be binary phase shift keying (BPSK, Binary Phase Shift Keying), quadrature amplitude modulation (MQAM, M-ary QuadratureAmplitude Modulation), any one in the current the most frequently used modulation system of these three kinds of MPSKs (MPSK, M-ary Phase Shift Keying).Improve the power consumption of system power utilance, reduction system, be all very important in a lot of practical applications, and as mobile phone, notebook, portable PDA, satellite etc., these equipment, in order to lengthen working hours, need to reduce equipment power dissipation as much as possible.

The complexity of the inventive method is lower, is convenient to realize in practical application; The inventive method can effectively improve the performance of system simultaneously, therefore is applicable to actual central application.

Summary of the invention

When communication system is carried out the Adaptive Transmission of signal, usually the problem faced is: after the modulation system (or bit number) of each allocation units (as subchannel, antenna etc.) is determined, how according to current channel transmission state, determine the power of transmitted signal for each allocation units, make system when meeting performance requirement (requiring as error rate of system), needed power reduces as far as possible.

The invention provides a kind of adaptive transmission method that is applicable to compound modulation, the method is according to modulation system, the error rate of system requirement of each allocation units in communication system, and channel transmission state in the same time not, automatically calculate and distribute the power of transmitted signal for each allocation units, when the system of assurance reaches the error rate of system requirement, reduced to greatest extent the transmitted signal gross power of system.System can adopt compound modulation, the modulation system that is each allocation units employing in system can be any one in binary phase shift keying (BPSK), quadrature amplitude modulation (MQAM), these three kinds of modulation systems commonly used of MPSK (MPSK), so the inventive method has very high flexibility.

The optimization aim of the inventive method can be sketched and be: in given, all allocation units modulation system (or bit number) of participating in the distribution of the aims of systems error rate under definite condition, for each allocation units of participating in the distribution distribute power, make the needed transmitted signal gross power of system minimum.This optimization aim and constraints can mean by following formula

Minimize $P_{\mathrm{Total}}=\underset{i=1}{\overset{N_C}{\mathrm{\Σ}}}{P}_i,$

Satisfy condition simultaneously $\underset{i=1}{\overset{N_C}{\mathrm{\Σ}}}{b}_i=R_b,$ $\underset{i=1}{\overset{N_C}{\mathrm{\Σ}}}\frac{E_i\·b_i}{R_b}\≤E_T,$ And P _i>=0, b _i>=0, E _i>=0, i=1,2 ..., N _c.P wherein _totalthe transmitted signal gross power of system, P _ii the transmitted signal power that allocation units distribute in system, b _ithe bit number (bit number of each allocation units is known conditions) of the distribution of i allocation units, E _iit is the target error rate of i allocation units.E _tthe target error rate of system, N _cthe sum of the allocation units of all participation power division, R _bit is the total number of bits order of participating in the distribution in each assigning process.

Below the key step of the inventive method is elaborated.

The first step: if in system, the modulation system of each allocation units is not specified, according to bit number, system that in system, each allocation units distributes, can use modulation system and systematic function requirement, determine the modulation system that each allocation units adopts, the modulation system of each allocation units is selected one in BPSK, MQAM and tri-kinds of modulation systems of MPSK.If the modulation system of each allocation units of system is specified, directly enter subsequent step.

Second step: according to channel estimation results, according to formula $C_i={\mathrm{\σ}}_i^2/a_i$ For the ratio of each allocation units calculating noise power and channel power gain, wherein parameter i means allocation units sequence number, C _imean noise power that i allocation units are corresponding and the ratio of channel power gain, σ _i ²mean i the noise power in allocation units, a _imean the channel power gain of i allocation units.

The 3rd step: the modulation system adopted according to each allocation units, all allocation units are divided into to three set L, M, N, and wherein L means to adopt set, the M of the allocation units of BPSK modulation system to mean to adopt set, the N of the allocation units of MQAM modulation system to mean to adopt the set of the allocation units of MPSK modulation system.

The 4th step: add up current all summation K that is excluded bit number in no allocation units _e, and according to formula B _e=0.2K _ethe errored bit number B that calculating is excluded _e.If while not having allocation units to be excluded, the errored bit number B be excluded _e=0.

The 5th step: according to formula $S=\frac{1}{W_{\mathrm{BPSK}}}\underset{l\∈L}{\mathrm{\Σ}}{C}_l+\frac{1}{W_{\mathrm{MQAM}}}\underset{m\∈M}{\mathrm{\Σ}}{C}_m(2^{b_m}-1)+\frac{1}{W_{\mathrm{MPSK}}}\underset{n\∈N}{\mathrm{\Σ}}{C}_n(2^{A\·b_n}+1)$ Calculate the value of the errored bit factor, wherein S means the errored bit factor, and l, m, n mean respectively to gather the allocation units sequence number in L, M, N, C _l, C _m, C _nthe ratio that noise power in expression set L, M, N and channel power gain respectively, b _m, b _nthe bit number that means respectively the allocation units in set M, N, W _bPSK, W _mQAM, W _mPSK, A is constant, these four constants are real number, require to carry out value, W according to systematic function and complexity within the specific limits _bPSKspan be 1～1.2, W _mQAMspan be 1～2, W _mSKspan be that the span of 5～9, A is 1.5～2.5.

The 6th step: according to formula F _bER=(E _tr _b-B _e)/S calculates the value of the error rate factor, wherein F _bERmean the error rate factor, E _tand R _bthe summation that means respectively bit number in the aims of systems error rate and all allocation units.

The 7th step: be the value of each allocation units calculating target error rate in set L, M, N.For set each allocation units in L according to formula $E_l=\frac{C_l}{W_{\mathrm{BPSK}}}\·F_{\mathrm{BER}}$ Calculate target error rate E _l, for set each allocation units in M according to formula $E_m=\frac{C_m(2^{b_m}-1)}{W_{\mathrm{MQAM}}\·b_m}\·F_{\mathrm{BER}}$ Calculate target error rate E _m, for set each allocation units in N according to formula $E_n=\frac{C_n(2^{A\·b_n}+1)}{W_{\mathrm{MPSK}}\·b_n}\·F_{\mathrm{BER}}$ Calculate target error rate E _n.

The 8th step: the value that checks the target error rate of each allocation units in set L, M, N, if exist the value of the target error rate of some allocation units to be not less than 0.2, these allocation units are got rid of from corresponding set, these allocation units are excluded no allocation units exactly, then turn back to " the 4th step " in above-mentioned steps.If the value of the target error rate of all allocation units all is less than 0.2, enter next step.The 9th step: for each allocation units calculates the transmitted signal performance number.Final each allocation units in pair set L, according to formula $P_l^{\mathrm{BPSK}}=-\frac{\ln \left({5E}_l\right)}{W_{\mathrm{BPSK}}}{C}_l$ Calculate the transmitted signal power P _l ^bPSK; Final each allocation units in pair set M, according to formula $P_m^{\mathrm{MQAM}}=-\frac{\ln \left({5E}_m\right)}{W_{\mathrm{MQAM}}}{C}_m(2^{b_m}-1)$ Calculate the transmitted signal power P _m ^mQAM; Final each allocation units in pair set N, according to formula $P_n^{\mathrm{MPSK}}=-\frac{\ln \left({5E}_n\right)}{W_{\mathrm{MPSK}}}{C}_n(2^{A\·b_n}+1)$ Calculate the transmitted signal power P _n ^mPSK; Be excluded no allocation units to all, the transmitted signal performance number is set to 0.

The tenth step: according to modulation system in each allocation units and transmitted signal performance number, generate corresponding transmitted signal, and carry out the transmission of signal.

It should be noted that, change the condition of getting rid of allocation units in above-mentioned steps " the 8th step " into " existing the transmitted signal performance number of some allocation units to be not more than 0; these allocation units are got rid of from corresponding set ", can not produce any impact to final signal parameter, because " the transmitted signal performance number is not more than 0 " is on all four with " value of target error rate is not less than 0.2 ".

In actual applications, according to system requirements, the order of above-mentioned each key step can suitably be adjusted as required.In addition, in actual applications, for ease of implementing, also part steps can be merged, can not exert an influence to final transmission signal and system transmission performance.

The characteristics of the inventive method are, the inventive method is not particularly limited the bit number of each allocation units, each allocation units can adopt any one in the current the most frequently used modulation system of these three kinds of BPSK, MQAM, MPSK, system can adopt compound modulation, can adopt as required the combination in any of above-mentioned three kinds of modulation systems, relax the restriction to signal, there is very high flexibility and adaptability; In each allocation units bit number or the fixed situation of modulation system, can determine for transmitted signal the signal power of the optimization adapted with channel condition by the inventive method, the assurance system, when meeting the bit error rate performance requirement, is reduced the power consumption of system as much as possible; The inventive method makes the transmitted signal power of each allocation units and the gross power of system, and all adaptive variations with the variation of channel condition can take full advantage of the transmission characteristic of channel; Adopted Optimum Design Results in the inventive method, guarantee the signal transmission that all can be optimized fast in each signals transmission, therefore the inventive method has advantages of that fast convergence rate, time overhead are little, is applicable to very much that channel variation is very fast, needs carry out the occasion of Adaptive Transmission parameter adjustment fast.In addition, the implementation complexity of each key step of the inventive method is all lower, and the power consumption while being conducive to the operation of reduction system is highly suitable for to need to reduce in equipment power dissipation, the occasion of extension device operating time and applies.

The accompanying drawing explanation

Fig. 1 is a kind of flow chart that is applicable to the adaptive transmission method of compound modulation that the present invention proposes.

Embodiment

In actual applications, by each key step of the inventive method, adjusted and optimized according to system requirements, form a plurality of subfunctions unit, then these subfunction unit are combined, realize the function of the inventive method as an allomeric function unit.

At FDD (Frequency Division Duplex, Frequency Division Duplexing (FDD)) in communication system, the present invention can be placed on emission and bring in enforcement, as a functional unit in transmitter, also can be placed on receive bring in enforcement, as a functional unit in receiver.

If enforcement is brought in the emission that the present invention is placed in the FDD system, carry out channel estimating by receiving terminal, receiving terminal is estimated channel power gain and the noise power-value of all allocation units.After having estimated, receiving terminal feeds back to transmitting terminal to these estimated informations.At transmitting terminal, determine transmitted signal power by functional unit of the present invention for each allocation units, then generate modulation signal, send signal in channel and transmitted.Receiving terminal, according to the adaptive modulation parameter information received, can carry out demodulation to the received signal, obtains the data of sending.

If realization is brought in the reception that the present invention is placed in the FDD system, still by receiving terminal, carry out channel estimating, channel power gain and the noise power-value of all allocation units are estimated.After having estimated, determined the transmitted signal power of each allocation units by functional unit of the present invention, then receiving terminal is transferred to transmitting terminal by the transmitted signal power results.Transmitting terminal, according to the parameter information that feeds back, is that each allocation units generate modulation signal, and sends signal in channel and transmitted.After receiving terminal receives signal, can carry out to the received signal demodulation.

At TDD (Time Division Duplex, time division duplex) in communication system, except can adopting the execution mode identical with the FDD system, can also adopt following working method: transmitting terminal is at first according to the data-signal or the pilot signal that send over from receiving terminal, channel is estimated, obtain channel power yield value and the noise power-value of each allocation units, then by functional unit of the present invention, determine each allocation units transmitted signal power, the signal finally generated after modulating is transmitted.

Just work when transmitted signal power need to be adjusted of functional unit of the present invention, when transmitted signal power does not need to be adjusted, functional unit of the present invention does not carry out work.

In actual applications, if in system, the modulation system of each allocation units is not specified, according to the inventive method, need to can use modulation system and systematic function requirement according to bit number, system that in system, each allocation units distributes, determine the modulation system that each allocation units adopts, the modulation system of each allocation units is selected one in BPSK, MQAM and tri-kinds of modulation systems of MPSK.

Below provided for example under 5 kinds of situations the result (allocation units 1,2, the bit number in 3,4 is respectively: " 1 ", " 2 ", " 4 ", " 5 ") of determining modulation system for each allocation units.It should be noted that QPSK and 4QAM are in fact identical modulation systems.

Sequence number

System can be used modulation system

The systematic function requirement

Allocation units 1 modulation system

Allocation units 2 modulation systems

Allocation units 3 modulation systems

Allocation units 4 modulation systems

Situation 1

BPSK、MPSK

Nothing

BPSK

QPSK

16PSK

32PSK

Situation 2

BPSK、MQAM

Nothing

BPSK

4QAM(QPSK)

16QAM

32QAM

Situation 3

BPSK、MQAM、 MPSK

Nothing

BPSK

QPSK(4QAM)

16PSK or 16QAM

32PSK or 32QAM

Situation 4

BPSK、MQAM、 MPSK

The preferential MPSK modulation system that adopts

BPSK

QPSK(4QAM)

16PSK

32PSK

Situation 5

BPSK、MQAM、 MPSK

The preferential MQAM modulation system that adopts

BPSK

4QAM(QPSK)

16QAM

32QAM

When the bit number in allocation units is worth for other (as " 3 ", " 6 ", " 7 ", " 8 ", " 9 ", " 10 " etc.), according to above-mentioned example, identical method is that allocation units are determined modulation system.

" allocation units " in the inventive method in actual applications, be need to determine modulation system and transmitted signal power physically or sky/time in logic/frequency Resource Block.The inventive method is determined modulation system and transmitted signal power for each allocation units.

In multicarrier system, do not adopt the mode that subchannel is divided into groups to divide timing, using each independently subchannel as allocation units.Below this situation is illustrated:

Example: comprise 4 sub-channels in multicarrier system, do not adopt subchannel is distributed.These 4 independently subchannel be exactly 4 allocation units.The power gain that obtains 4 sub-channels by channel estimating is respectively { 0.6; 1.5; 0.4; 0.3} the noise power of every sub-channels is 0.1 milliwatt, the gain of the channel power of 4 allocation units is just { 0.6 so; 1.5; 0.4; 0.3} the noise power of each allocation units is 0.1 milliwatt.

In multicarrier system, adopt the mode that subchannel is divided into groups to divide timing, " equivalent subchannel " that each sub-channels grouping is generated is as allocation units.Below this situation is illustrated:

Example: comprise 16 sub-channels in multicarrier system, 4 sub-channels are divided into to one group, being divided into is 4 groups.4 sub-channels in every group generate one " equivalent subchannel ", and these 4 " equivalent subchannels " are exactly 4 allocation units.Channel power gain and the noise power of " equivalent subchannel ", channel power gain and the noise power of 4 sub-channels in the correspondence grouping generate.By channel estimating, the power gain that obtains 16 sub-channels is respectively { (0.6,0.9,0.8,0.7); (1.8,1.7,1.5,1.6); (0.76,0.95,0.4,0.64); (0.45,0.76,0.55,0.3) }, the noise power of every sub-channels is 0.1 milliwatt.Get the channel power gain of the minimum value of each grouping sub-channels power gain as " equivalent subchannel ", the namely channel power of these corresponding allocation units that divide into groups gain, thus the channel power gain that obtains 4 allocation units is { 0.6; 1.5; 0.4; 0.3}; Get the mean value of noise power in each grouping as the noise power-value of " equivalent subchannel ", this noise power-value of corresponding allocation units of dividing into groups namely, thus the noise power that obtains each allocation units is 0.1 milliwatt.It should be noted that the channel power gain of generation " equivalent subchannel " and the multiple choices method that noise power can have other.

In multiaerial system, using each dual-mode antenna between " equivalent transmission channel " as allocation units.Below this situation is illustrated:

Example: comprise 2 subcarriers in the MIMO-OFDM system, and the sending and receiving antenna each 2.Pass through channel estimating, can obtain the transmission matrix on each carrier wave, transmission matrix on each carrier wave is carried out to the SVD decomposition, can obtain 2 independently " equivalent transmission channels ", on such 2 carrier waves, can obtain altogether 4 " equivalent transmission channels ", these 4 " equivalent transmission channels " are exactly 4 allocation units.Decomposing by SVD the transducer power gain that obtains 4 " equivalent transmission channels " is { 0.6; 1.5; 0.4; 0.3} 4 channel power gains corresponding to allocation units are just { 0.6 so; 1.5; 0.4; 0.3}.Obtain 4 noise powers in " equivalent transmission channel " by channel estimating and be 0.1 milliwatt, the noise power in each allocation units is 0.1 milliwatt so.

In conjunction with above-mentioned example, other steps of the inventive method are described.To top three examples, the ratio that calculates noise power and channel power gain for each allocation units is: { 0.167; 0.067; 0.250; 0.333}.

If 4 allocation units modulation systems used are { BPSK; 4QAM; 16QAM; 32PSK} is divided into three set L, M, N by 4 allocation units according to modulation system: set L for allocation units 1}, set M is { allocation units 2; Allocation units 3}, set N is { allocation units 4}.

Add up current all summation K that is excluded bit number in no allocation units _e, when initial, do not have allocation units to be excluded, K _e=0, the errored bit number B of eliminating _e=0.

Selectivity constant W _bPSK=1.06, W _mQAM=1.6, W _mPSK=7, A=1.9, the value of these four constants is all within span.The value that calculates the errored bit factor is S=37.12.

If the aims of systems error rate is E _t=10 ^-3, the total number of bits in 4 allocation units is R _b=12, the value that can obtain the error rate factor is F _bER=3.23 * 10 ^-4, the target error rate that can obtain 4 allocation units is respectively

Allocation units 1:E ₁=5.09 * 10 ^-5,

Allocation units 2:E ₂=2.03 * 10 ^-5,

Allocation units 3:E ₃=1.89 * 10 ^-4,

Allocation units 4:E ₄=2.23 * 10 ^-3.

Because the value of the target error rate of 4 allocation units all is less than 0.2, therefore do not have allocation units to need to get rid of.Next, can obtain the transmitted signal power letter of 4 allocation units, be respectively

Allocation units 1: $P_1^{\mathrm{BPSK}}=1.30$ Milliwatt,

Allocation units 2: $P_2^{\mathrm{MQAM}}=1.16$ Milliwatt,

Allocation units 3: $P_3^{\mathrm{MQAM}}=16.32$ Milliwatt,

Allocation units 4: $P_4^{\mathrm{MPSK}}=115.10$ Milliwatt.

The transmitted signal parameter that finally obtains 4 allocation units is as follows:

Sequence number	Allocation units 1	Allocation units 2	Allocation units 3	Allocation units 4
					The signal modulation system	BPSK	QPSK	16QAM	32PSK
Transmitted signal power	1.30 milliwatt	1.16 milliwatt	16.32 milliwatt	115.10 milliwatt

Finally, according to above-mentioned transmitted signal parameter, generate corresponding transmitted signal, and the transmitted signal generated is transmitted, completed the Adaptive Transmission process of system.

In actual applications, according to system requirements, can be adjusted each functional unit of the present invention, by the partial function mesh merging, so that system realizes.For example, can be by errored bit factor S, error rate factor F _bER, allocation units target error rate E _i(i=1,2,3,4) merge with these functional units of allocation units transmitted signal power, become the unit of a direct dispensed unit transmitted signal power.While dispensing the functional unit of the dispensed unit object error rate, can utilize the condition of amended eliminating allocation units, get rid of obsolete allocation units, " exist the transmitted signal performance number of some allocation units to be not more than 0; these allocation units are got rid of from corresponding set ", on final signal parameter, can not produce any impact.

Claims (5)

1. an adaptive transmission method that is applicable to compound modulation, it is characterized in that, comprise the following steps: (1) is not if in system, the modulation system of each allocation units is specified, according to bit number, system that in system, each allocation units distributes, can use modulation system and systematic function requirement, determine the modulation system that each allocation units adopts, the modulation system of each allocation units is selected one in tri-kinds of modulation systems of BPSK, MQAM profit MPSK, if the modulation system of each allocation units of system is specified, directly enter subsequent step; (2) according to channel estimation results, according to formula

for the ratio of each allocation units calculating noise power and channel power gain, wherein parameter i means allocation units sequence number, C _imean noise power that i allocation units are corresponding and the ratio of channel power gain,

mean i the noise power in allocation units, a _imean the channel power gain of i allocation units; (3) modulation system adopted according to each allocation units, be divided into three set L, M, N by all allocation units, and wherein L, M, N mean respectively to adopt the set of the allocation units of BPSK modulation system, MQAM modulation system and MPSK modulation system; (4) add up current all summation K that is excluded bit number in no allocation units _e, and according to formula B _e=0.2K _ethe errored bit number B that calculating is excluded _eif do not have allocation units to be excluded, B _e=0; (5) according to formula $S=\frac{1}{W_{\mathrm{BPSK}}}\underset{l\∈L}{\mathrm{\Σ}}{C}_l+\frac{1}{W_{\mathrm{MQAM}}}\underset{m\∈M}{\mathrm{\Σ}}{C}_m(2^{b_m}-1)+\frac{1}{W_{\mathrm{MPSK}}}\underset{n\∈N}{\mathrm{\Σ}}{C}_n(2^{A\·b_n}+1)$ Calculate the value of the errored bit factor, wherein S means the errored bit factor, and l, m, n mean respectively to gather the allocation units sequence number in L, M, N, C _l, C _m, C _nthe ratio that noise power in expression set L, M, N and channel power gain respectively, b _m, b _nthe bit number that means respectively the allocation units in set M, N, W _bPSK, W _mQAM, W _mPSK, A is constant, and is real number, requires to carry out value, W according to systematic function and complexity within the specific limits _bPSKvalue be 1.06, W _mQAMvalue be 1.6, W _mPSKvalue be 7, A value is 1.9; (6) according to formula F _bER=(E _tr _b-B _e)/S calculates the value of the error rate factor, wherein F _bERmean the error rate factor, E _tand R _bthe summation that means respectively bit number in the aims of systems error rate and all allocation units: (7) calculate the value of target error rate for each allocation units in set L, M, N, for each allocation units in set L according to formula

calculate target error rate E _l, for set each allocation units in M according to formula calculate target error rate E _m, for set each allocation units in N according to formula calculate target error rate E _n; (8) check the value of the target error rate of each allocation units in set L, M, N, if exist the value of the target error rate of some allocation units to be not less than 0.2, these allocation units are got rid of from corresponding set, and turn back to step (4), if the value of the target error rate of all allocation units all is less than 0.2, enter next step; (9) for each allocation units calculates the transmitted signal performance number, each allocation units final in pair set L are according to formula

calculate the transmitted signal power P _l ^bPSK, each allocation units final in pair set M are according to formula

calculate transmitted signal power

each allocation units final in pair set N are according to formula

calculate transmitted signal power

be excluded no allocation units to all, the transmitted signal performance number is set to 0; (10) according to modulation system in each allocation units and transmitted signal performance number, generate corresponding transmitted signal, and carry out the transmission of signal.

2. a kind of adaptive transmission method that is applicable to compound modulation according to claim 1, it is characterized in that: in multicarrier system, do not adopt the mode that subchannel is divided into groups to divide timing, using each independently subchannel as allocation units.

3. a kind of adaptive transmission method that is applicable to compound modulation according to claim 1, it is characterized in that: in multicarrier system, the mode that employing is divided into groups to subchannel is divided timing, and the equivalent subchannel that each sub-channels grouping is generated is as allocation units.

4. a kind of adaptive transmission method that is applicable to compound modulation according to claim 1 is characterized in that: in multiaerial system, using each dual-mode antenna between equivalent transmission channel as allocation units.

5. a kind of adaptive transmission method that is applicable to compound modulation according to claim 1, it is characterized in that: the condition that will get rid of allocation units changes " existing the transmitted signal performance number of some allocation units to be not more than 0; these allocation units are got rid of from corresponding set " into, on final signal parameter, can not produce any impact.