CN101764682B - Method and device for selecting modulation code configuration - Google Patents

Abstract

The invention discloses a method for selecting modulation code configuration. The method comprises that: the current RBIRm corresponding to each modulation mode m is determined according to the SINR of all subcarriers, and RBIR corresponding to each code rate to be selected under the modulation mode is determined according to target error rate; the matching code rate of the modulation mode is selected from the determined RBIR corresponding to the code rate to be selected under the modulation mode, and finally, a product obtained through multiplying bit number carried by modulation symbols under each modulation mode by the matching code rate of the modulation mode is calculated, a maximum value is selected from all products, and the modulation mode and the code rate corresponding to the maximum value are used as the selected results of the modulation code configuration. The invention additionally provides a device for selecting the modulation code configuration. The invention has the advantages that the spectral efficiency is maximized and the throughput is maximized on the premise that the BLER performance is guaranteed.

Description

A kind of system of selection of modulation code configuration and device

Technical field

The present invention relates to various wireless communication systems, be specifically related to a kind of system of selection and device of modulation code configuration.

Background technology

In wireless communication system, the channel quality information that link adaptation techniques feeds back according to control channel (Channel Quality Indicator, CQI) select suitable modulation system and the combination of encoder bit rate, so that the throughput of system reaches maximum, this technology is called as coded modulation configuration (Modulation Coding Scheme, MCS) and selects.MCS selects to need to adopt a kind of effective signal-to-noise ratio mapping method (Effective SNR Mapping, ESM) Block Error Rate (the Block Error Rate under the prediction current channel condition, BLER) performance, thus suitable modulation system and encoder bit rate selected.

Channel in the wireless communication system is subjected to the impact of translational speed and multipath, usually has time selectivity and frequency selectivity.In OFDM (Orthogonal Frequency Division Multiplexing) system, it is very obvious that SNR value on each subcarrier changes in whole frequency band, and the high-speed mobile of terminal and HARQ retransmit the variation that will cause the SNR in the decode block.Equivalence SNR mapping is so that the symbol SNR value that changes in the next encoding block of different channels is mapped to the SNR value of an equivalence, and this equivalent SNR and the relation curve of corresponding BLER can be approximately the relation curve of the SNR-BLER under the awgn channel.So just various fading channel equivalences can be studied for awgn channel.This process also is referred to as link level to system-level mapping process.Method commonly used has exponential type equivalence SNR mapping (Exponential Effective SNR Mapping, EESM) with based on the equivalent SNR mapping (Mutual Information-based Effective SNR Mapping, MIESM) of mutual information.Equivalence SNR mapping process can be with reference to shown in Figure 1, and its course of work is as follows:

In system-level emulation, obtain the wanted to interfering signal ratio (SINR) on each subcarrier after the equilibrium of frequency-selective channel process receiving terminal, thereby obtain the average wanted to interfering signal ratio (SINR) on every sub-channels;

With EESM method or MIESM method, the SINR on a plurality of subchannels is mapped as an equivalent SNR value, then search the BLER corresponding with this equivalent SNR value at the AWGN reference curve _AWGN

System-level BLER and BLER _AWGNSuch relation is arranged: BLER ≈ BLER _AWGNArrive systematic function with regard to measurable accordingly, thereby carry out link layer self adaptation, scheduling, HARQ etc.

The mathematic(al) representation of equivalence SNR mapping is

${\mathrm{SNR}}_{\mathrm{eff}}={\mathrm{\Φ}}^{-1}\left(\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{\Φ}\left({\mathrm{SINR}}_n\right)\right)---\left(1\right)$

SNR _EffRepresent equivalent SNR value, SINR _nRepresent n the SINR value on the subcarrier; N is subcarrier number used in the ofdm system, the mapping function that Φ () expression is reversible.

The mathematic(al) representation of EESM method is

${\mathrm{SNR}}_{\mathrm{eff}}=-\mathrm{\β}\ln [\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\exp (-\frac{{\mathrm{SINR}}_n}{\mathrm{\β}})---\left(2\right)$

β is the factor of optimizing and revising that depends on modulation system and code check and coding block length in the formula (2).The EESM method is underaction on each sub-carrier selection modulation system, and β adjusts more complicated.

The mathematic(al) representation of MIESM method is

${\mathrm{SNR}}_{\mathrm{eff}}={\mathrm{SI}}^{-1}\left[\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{SI}({\mathrm{SINR}}_n,m\left(n\right))\right]---\left(3\right)$

In the formula (3), the entrained bit number of modulation symbol on n subcarrier of m (n) expression; SI (SINR _n, m (n)) and expression symbol mutual information.

If M represents the corresponding constellation point number of modulation system, U represents that average is zero on n the subcarrier, and component variance is 1/ (2SINR _n) multiple Gaussian noise, then symbol mutual information SI (SINR _n, m (n)) can be obtained by following formula (4)

$\mathrm{SI}({\mathrm{SINR}}_n,m\left(n\right))=\underset{i}{\mathrm{\Σ}}\∫p\left(y\right|x_i)P\left(x_i\right){\log }_2\frac{p\left(y\right|x_i)}{p\left(y\right)}\mathrm{dy}$

$={\log }_{2}M-\frac{1}{M}\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{E}_U\left\{{\log }_2(1+\underset{k=1,k\≠m}{\overset{M}{\mathrm{\Σ}}}\exp [-\frac{{|x_k-x_m+U|}^2-{\left|U\right|}^2}{(1/{\mathrm{SINR}}_n)}\left]\right)\right\}---\left(4\right)$

Symbol mutual information under QPSK, 16QAM, the 64QAM modulation system and the relation curve of SNR are as shown in Figure 2.

Order $\mathrm{MI}=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{SI}({\mathrm{SINR}}_n,m\left(n\right))$ (5) be the average symbol mutual information.

Every bit Average Mutual RBIR (Received BitInformation Rate) that can be obtained receiving by the symbol mutual information is

$\mathrm{RBIR}=\frac{\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{SI}({\mathrm{SINR}}_n,m\left(n\right))}{\underset{n=1}{\overset{N}{\mathrm{\Σ}}}m\left(n\right)}---\left(6\right)$

It is irrelevant with modulation system because the relation between RBIR and the BLER only depends on code check that coding adopts, no matter so adopt any modulation system according to the symbol on the subcarrier, according to RBIR just directly can prognoses system the BLER performance, do not need to be mapped as first SNR _EffPredict again BLER.

The relative EESM of MIESM can be awgn channel with various fading channel equivalences more accurately, therefore carries out MCS with MISEM and selects.Existing system of selection is at first to determine modulation system according to the size of average symbol mutual information, and then selects code check, and method is as follows:

1, according on a series of subcarriers ... SINR _n, according to formula (5) and (6), corresponding every kind of modulation system m calculates respectively MI _mAnd RBIR _m

2, under target BLER, find by statistics, usually have an offset delta between the code check value of system and the RBIR of this system, and under different code checks, offset delta remains unchanged substantially.Therefore can be by the RBIR that in step 1, calculates _mIn deduct δ, thereby obtain its corresponding code check value RBIR _m', i.e. RBIR _m'=RBIR _m-δ;

3, establishing the entrained bit number of modulation symbol is M (m), and then corresponding every kind of modulation system obtains a MI _m'=M (m) RBIR _m'.

Get $m^{\′}=\underset{m}{\arg \max }\left\{{{\mathrm{MI}}_m}^{\′}\right\},$ M ' is the selected modulation system of MCS.

In the code check set corresponding to m ', the code fetch rate is lower than RBIR _{M '}' but and RBIR _{M '}' the code check that approaches the most is as the selected code check of MCS.If code check all is higher than RBIR _{M '}, it is the selected encoder bit rate of MCS that lowest bit rate then is set.

There is defective in above-mentioned MCS system of selection based on MIESM.Be analyzed as follows:

As shown in Figure 2, the symbol mutual information curve of QPSK, 16QAM, 64QAM can roughly be divided into four-stage: first paragraph is before 5dB, the symbol mutual information of QPSK, 16QAM, 64QAM modulation is all rising, and the symbol mutual information of QPSK is a little more than other two kinds of modulation systems; To between the 10dB, the symbol mutual information of this stage 16QAM will be a little more than the symbol mutual information of 64QAM at 5dB for second segment, and the symbol mutual information of QPSK is minimum, is in platform 2; The 3rd section between 10dB and 20dB, the symbol mutual information of 64QAM continue to rise, and the symbol mutual information of 16QAM reaches platform 4 gradually; The 4th section after 20dB, the symbol mutual information of 64QAM reaches platform 6.

Calculate MI _m'=MI _m-M δ has widened in fact the symbol mutual information difference of the symbol mutual information is the highest in first paragraph and second segment respectively QPSK, 16QAM and other two kinds of modulation systems, as shown in Figure 3.

Can obtain thus such conclusion: the MI that compares the different modulating mode _m' come the definite modulation system that will select, in fact still compare the entrained mutual information of the every symbol of different modulating mode.The defective that this method has is:

(1) ignored this restrictive condition of systematic function BLER.Because the MI of high order modulation _m' can be higher than the MI of low-order-modulated _m', for example at second segment from 5dB, MI _16QAM' can be higher than MI _QPSK', so can select the 16QAM modulation.But adopt the BLER of the modulation system of 16QAM can be higher this moment, do not satisfy system to the requirement of BLER performance.Therefore only compare MI _m' size, usually can select and be not suitable for current channel condition, the high order modulation of discontented pedal system BLER performance.

(2) said method is in unique selection of carrying out again code check after having determined modulation system, and selecting modulation mode and encoder bit rate is fully separated.And often system given be the assembled scheme of Different Modulations and encoder bit rate.

(3) it is low to carry out the accuracy that MCS selects.Because δ is an estimated value, is not very accurate.And in Fig. 3, usually carry out the selection of modulation system according to the fine difference between the different modulating mode.In case modulation system is selected mistake, further can affect the selection of code check.

Summary of the invention

In view of this, the invention provides system of selection and the device of a kind of MCS, can select modulation system and the code check of adaptive channel state, satisfy system to the requirement of performance, simultaneously so that throughput of system is maximum.

For achieving the above object, the present invention adopts following technical scheme:

A kind of system of selection of modulation code configuration comprises:

For every kind of Block Error Rate, under various modulation systems, preserve every bit Average Mutual RBIR corresponding to each code check to be selected under the awgn channel in advance;

Corresponding every kind of modulation system m, carry out following operation:

Determine the RBIR of the current correspondence of this modulation system according to the SINR of all subcarriers _m, and, determine under this modulation system RBIR corresponding to each code check to be selected under the described awgn channel according to the target block error rate BLER; Among the RBIR that each code check to be selected is corresponding under this modulation system of determining, select to be not more than and near the RBIR of the current correspondence of this modulation system _mRBIR, and determine that code check corresponding to selected RBIR is as the cooperation code check of this modulation system;

That calculates the entrained bit number of every kind of modulation system modulated symbol and this modulation system cooperates code check long-pending, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

Preferably, for arbitrary modulation system, be not more than RBIR if do not exist _mRBIR, judge then whether this modulation system is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under this modulation system is as the cooperation code check of this modulation system; Otherwise the cooperation code check of determining this modulation system is 0.

Preferably, the RBIR of the current correspondence of described definite modulation system m _mFor: ${\mathrm{RBIR}}_m=\frac{\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{SI}({\mathrm{SINR}}_n,m\left(n\right))}{\underset{n=1}{\overset{N}{\mathrm{\Σ}}}m\left(n\right)},$ Wherein, the entrained bit number of modulation symbol on n subcarrier of m (n) expression, N is total number of sub-carriers used in the system.

A kind of choice device of modulation code configuration comprises: equalizer, comparator, with various modulation systems one to one RBIR calculator, memory and code rate selection device;

Equalizer is used for determining the SINR of all subcarriers, and exports to all RBIR calculators;

The memory that arbitrary modulation system is corresponding is used for for every kind of Block Error Rate, under corresponding modulation system, preserves every bit Average Mutual RBIR corresponding to each code check to be selected under the AWGH channel;

The RBIR calculator that arbitrary modulation system is corresponding is used for the SINR according to all subcarriers that receive, and determines the RBIR of the current correspondence of corresponding modulation system _m, and export to code rate selection device corresponding to corresponding modulation system;

The code rate selection device that arbitrary modulation system is corresponding is used for according to the target Block Error Rate, extracts RBIR corresponding to described each code check to be selected in memory corresponding to corresponding modulation system; And in RBIR corresponding to each code check to be selected that extracts, select to be not more than and near the RBIR of described RBIR calculator input _mRBIR, and determine that code check corresponding to selected RBIR as the cooperation code check of corresponding modulation system, export to described comparator;

Described comparator, be used for calculating the amassing of cooperation code check that every kind of entrained bit number code rate selection device corresponding with this modulation system of modulation system modulated symbol is inputted, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

Preferably, the code rate selection device that arbitrary modulation system is corresponding is further used for being not more than RBIR not existing _mRBIR the time, judge whether corresponding modulation system is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under the corresponding modulation system is as the cooperation code check of this modulation system; Otherwise the cooperation code check of determining corresponding modulation system is 0.

As seen from the above technical solution, among the present invention, in advance for every kind of Block Error Rate, under various modulation systems, preserve RBIR corresponding to each code check to be selected under the awgn channel; Then, corresponding every kind of modulation system m determines the RBIR of the current correspondence of this modulation system according to the SINR of all subcarriers _m, and, determine under this modulation system RBIR corresponding to described each code check to be selected according to target error rate; Among the RBIR that each code check to be selected is corresponding under this modulation system of determining, select to be not more than and near the RBIR of the current correspondence of this modulation system _mRBIR, and determine that code check corresponding to selected RBIR is as the cooperation code check of this modulation system; At last, that calculates the entrained bit number of every kind of modulation system modulated symbol and this modulation system cooperates code check long-pending, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the code check selection result as modulation code configuration.By the way, according to target BLER requirement, under various modulation systems, select only code check as cooperating code check, carrying out MCS again from the combination of all modulation systems and cooperation code check selects, thereby can be under the prerequisite that guarantees the BLER performance, so that spectrum efficiency is the highest, throughput is maximum.

Description of drawings

Fig. 1 is the schematic diagram of equivalent SNR mapping process.

Fig. 2 is symbol mutual information under QPSK, 16QAM, the 64QAM modulation system and the relation curve schematic diagram of SNR.

Fig. 3 is the particular flow sheet of the system of selection of modulation code configuration among the present invention.

Fig. 4 is the concrete structure figure of the choice device of modulation code configuration among the present invention.

Fig. 5 is RBIR under awgn channel of 11 kinds of assembled schemes～BLER reference curve in the LTE system.

Fig. 6 is 11 kinds of assembled scheme SNR under awgn channel and the relation curve of BLER in the LTE system.

The relation curve of throughput of system and equivalent SNR when Fig. 7 selects for carry out MCS according to method of the present invention.

Embodiment

For making purpose of the present invention, technological means and advantage clearer, below in conjunction with accompanying drawing, the present invention is described in further details.

Basic thought of the present invention is: under target BLER, determine that at first various modulation systems mate only cooperation code check, again various modulation systems with cooperate code check in carry out the MCS selection.

Fig. 3 is the particular flow sheet of the system of selection of modulation code configuration among the present invention.As shown in Figure 1, the method comprises:

Step 301 in advance for every kind of Block Error Rate, under various modulation systems, is preserved RBIR corresponding to each code check to be selected under the awgn channel.

Under every kind of modulation system, all there is the set of code check, comprising all code checks to be selected that can make up with this modulation system.

In this step, be that the various modulation systems under every kind of Block Error Rate are preserved a tabulation in advance, wherein record the corresponding RBIR of each code check to be selected in the code check set of corresponding modulation system under the awgn channel.Wherein, the corresponding RBIR of each code check to be selected can obtain according to reference curve shown in Figure 5 under the awgn channel.Fig. 5 is RBIR under awgn channel of 11 kinds of modulating-coding assembled schemes of LTE system～BLER reference curve, and the simulation parameter that obtains this curve is: adopt the Turbo coding, Max-Log-MAP decoding algorithm, 8 iteration.

Corresponding every kind of modulation system is execution in step 302～304 respectively, determines under the target BLER and the optimal code check of various modulation systems, namely cooperates code check, next describes as an example of arbitrary modulation system m example:

Step 302, according to the SINR on all subcarriers, corresponding modulating mode m calculates respectively RBIR _m

In this step, the mode of calculating RBIR corresponding to modulation system m according to SINR is identical with existing mode, namely can utilize formula (6) to calculate.

Step 303 according to target BLER, is extracted RBIR corresponding to each code check to be selected that preserves under the modulation system m.

Step 304 among all RBIR that extract in step 103, is selected to be not more than and near the RBIR of the current correspondence of this modulation system _mRBIR, and determine that code check corresponding to selected RBIR is as the cooperation code check CR of this modulation system _m

In this step, with calculate in the step 302 with step 303 in all RBIR of extracting compare, select to be not more than and near the RBIR of the current correspondence of this modulation system _mA RBIR value, the code check that this RBIR value is corresponding is the optimal code check with modulation system m, i.e. the cooperation code check of modulation system m.With this modulation system and the to be selected combination of the combination that cooperates code check as final MCS.

In addition, if in this step through relatively finding, not existing to be not more than and near the RBIR of the current correspondence of this modulation system _mRBIR, then preferably, judge further whether modulation system m is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under this modulation system is as the cooperation code check CR of this modulation system _mOtherwise, determine the cooperation code check CR of this modulation system _mBe 0

By above-mentioned steps 302～304, select the cooperation code check CR of every kind of modulation system _m

Step 305 to each modulation system m, is calculated the entrained bit number of this modulation system modulated symbol and the CR of this modulation system _mLong-pending.

In this step, to each modulation system m, calculate M (m) CR _m, wherein, for M (m) is the entrained bit number of modulation system m modulated symbol.

Step 306 is selected maximum in all result of product that step 305 obtains, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

So far, the MCS system of selection flow process among the present invention finishes.After the application aforesaid way carried out the MCS selection, the computing formula of throughput of system was Throughput=M (m) CR _m(1-BLER).

More than be the embodiment of MCS system of selection among the present invention, in addition, the present invention also provides a kind of MCS choice device, as shown in Figure 4, this device comprise equalizer, comparator, with various modulation systems one to one RBIR calculator, memory and code rate selection device.

In this device, equalizer is used for determining the SINR of all subcarriers, and exports to all RBIR calculators;

The memory that arbitrary modulation system is corresponding is used for for every kind of Block Error Rate, under corresponding modulation system, preserves every bit Average Mutual RBIR corresponding to each code check to be selected under the awgn channel;

The RBIR calculator that arbitrary modulation system is corresponding is used for the SINR according to all subcarriers that receive, and determines the RBIR of the current correspondence of corresponding modulation system _m, and export to code rate selection device corresponding to corresponding modulation system;

The code rate selection device that arbitrary modulation system is corresponding is used for according to the target Block Error Rate, extracts RBIR corresponding to described each code check to be selected in memory corresponding to corresponding modulation system; And in RBIR corresponding to each code check to be selected that extracts, select to be not more than and near the RBIR of described RBIR calculator input _mRBIR, and determine that code check corresponding to selected RBIR as the cooperation code check of corresponding modulation system, export to described comparator;

Comparator, be used for calculating the amassing of cooperation code check that every kind of entrained bit number code rate selection device corresponding with this modulation system of modulation system modulated symbol is inputted, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

Wherein, preferably, the code rate selection device that arbitrary modulation system is corresponding is further used for being not more than RBIR not existing _mRBIR the time, judge whether corresponding modulation system is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under the corresponding modulation system is as the cooperation code check of this modulation system; Otherwise the cooperation code check of determining corresponding modulation system is 0.

By the specific implementation of the invention described above as seen, method and apparatus of the present invention can be according to the rational selecting modulation mode of channel condition information and encoder bit rate, and under the prerequisite that guarantees the BLER performance, so that spectrum efficiency is the highest, throughput is maximum.

The present invention is applicable to the link adaptation techniques in the various wireless communication systems, comprising: 3G technology, LTE, LTE-Advanced, IMT-Advance etc.; And be applicable to various channel coding schemes, for example: Turbo code, LDPC code, convolution code etc.

Below providing the MCS of 3GPP LTE system on down link that utilizes method and apparatus of the present invention to realize selects.And compare with existing MCS system of selection in the background technology.

Provided the scheme of 15 kinds of modulation systems and code check combination in the 3GPP LTE agreement, removed CQI=1,2,3 are used for control channel, and CQI=15 these four kinds of situations.

As previously mentioned, Fig. 5 is the RBIR of 11 kinds of assembled schemes under awgn channel～BLER reference curve, adopts the Turbo coding, Max-Log-MAP decoding algorithm, 8 iteration.Given target BLER is 0.1, can obtain δ ≈ 0.11 by the relation of RBIR and code check in this curve.Distinguish as follows according to the selection result that the existing MCS system of selection in the background technology is selected to provide with this patent:

Under the TU channel, the translational speed of travelling carriage is 3km/h.According to engrave at a time one group of subcarrier ... SINR _n, according to formula (5) and (6), calculate the MI under QPSK, 16QAM, the 64QAM modulation system _QPSK=1.3759, MI _16QAM=1.6429, MI _64QAM=1.6628; RBIR _QPSK=0.6880, RBIR _16QAM=0.4107, RBIR _64QAM=0.2771.

Select with existing MCS system of selection, at first calculate MI _QPSK'=1.1559, MI _16QAM'=1.2029, MI _64QAM'=1.0028; Then compare MI _QPSK', MI _16QAM', MI _64QAM', because MI _16QAM' maximum, the modulation system of therefore selecting are the 16QAM modulation; Because MI _16QAM'/4=0.3007 is lower than all code checks under the 16QAM modulation, then selects lowest bit rate 0.3691.What have method MCS selection result now is the 16QAM modulation, code check 0.3691.

Select with the MCS system of selection that the present invention provides: at first calculate RBIR under the QPSK modulation _QPSK=0.6880, and in three kinds of code checks of QPSK modulation, select, selection result is CR _QPSK=0.5879; Next, calculate the lower RBIR of 16QAM modulation _16QAM=0.4147, and in three kinds of code checks of 16QAM, select, selection result is CR _16QAM=0; Then, calculate the lower RBIR of 64QAM modulation _64QAM=0.2771, and in five kinds of code checks of 64QAM modulation, select, CR obtained _64QAM=0; At last, three kinds of modulation systems are compared, determine that the result that MCS selects is the QPSK modulation, code check is 0.5879.

Relatively more existing MCS selects to select with MCS of the present invention: current channel status, according to formula (3), can obtain the signal to noise ratio of equivalence about 3dB, according to Fig. 6 as seen, in the situation of QPSK modulation, code check 0.5789 (being curve 603), corresponding BLER performance is below 0.1, and in the situation of 16QAM modulation, code check 0.3691 (being curve 604), corresponding BLER performance needs to start re-transmission far above 0.1, thereby causes throughput to descend.And in 11 kinds of assembled schemes of upper example, carry out system throughput discharge curve example that MCS selects as seen by employing shown in Figure 7 method and apparatus of the present invention, MCS system of selection provided by the present invention is more reasonable, guaranteed the BLER performance of system, simultaneously also so that throughput is maximum.

Being preferred embodiment of the present invention only below, is not for limiting protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. the system of selection of a modulation code configuration is characterized in that, the method comprises:

For every kind of Block Error Rate, under various modulation systems, preserve every bit Average Mutual (RBIR) corresponding to each code check to be selected under the awgn channel in advance; Every bit Average Mutual that each code check to be selected is corresponding under the described awgn channel is determined by system emulation;

Corresponding every kind of modulation system m, carry out following operation:

Determine the RBIR of the current correspondence of this modulation system according to the wanted to interfering signal ratio (SINR) of all subcarriers _m, and, determine under this modulation system RBIR corresponding to each code check to be selected under the described awgn channel according to the target block error rate BLER; Among the RBIR that each code check to be selected is corresponding under this modulation system of determining, select to be not more than and near the RBIR of the current correspondence of this modulation system _mRBIR, and determine that code check corresponding to selected RBIR is as the cooperation code check of this modulation system;

That calculates the entrained bit number of every kind of modulation system modulated symbol and this modulation system cooperates code check long-pending, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

2. method according to claim 1 is characterized in that, for arbitrary modulation system, is not more than RBIR if do not exist _mRBIR, judge then whether this modulation system is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under this modulation system is as the cooperation code check of this modulation system; Otherwise the cooperation code check of determining this modulation system is 0.

3. method according to claim 1 is characterized in that, the RBIR of the current correspondence of described definite modulation system m _mFor:

Wherein, SI (SINR _n, m (n)) and be the symbol mutual information, SINR _nBe the wanted to interfering signal ratio of n subcarrier, the entrained bit number of modulation symbol on n subcarrier of m (n) expression, N is total number of sub-carriers used in the system.

4. the choice device of a modulation code configuration is characterized in that, this device comprises: equalizer, comparator, with various modulation systems one to one RBIR calculator, memory and code rate selection device;

Equalizer is used for determining the wanted to interfering signal ratio (SINR) of all subcarriers, and exports to all RBIR calculators;

The memory that arbitrary modulation system is corresponding is used for for every kind of Block Error Rate, under corresponding modulation system, preserves every bit Average Mutual (RBIR) corresponding to each code check to be selected under the AWGH channel; Every bit Average Mutual that each code check to be selected is corresponding under the described awgn channel is determined by system emulation;

The RBIR calculator that arbitrary modulation system is corresponding is used for the SINR according to all subcarriers that receive, and determines the RBIR of the current correspondence of corresponding modulation system _m, and export to code rate selection device corresponding to corresponding modulation system;

The code rate selection device that arbitrary modulation system is corresponding is used for according to the target Block Error Rate, extracts RBIR corresponding to described each code check to be selected in memory corresponding to corresponding modulation system; And in RBIR corresponding to each code check to be selected that extracts, select to be not more than and near the RBIR of described RBIR calculator input _mRBIR, and determine that code check corresponding to selected RBIR as the cooperation code check of corresponding modulation system, export to described comparator;

Described comparator, be used for calculating the amassing of cooperation code check that every kind of entrained bit number code rate selection device corresponding with this modulation system of modulation system modulated symbol is inputted, and in all result of product, select maximum, with the corresponding modulation system of this maximum and the selection result that cooperates code check as modulation code configuration.

5. device according to claim 4 is characterized in that, the code rate selection device that arbitrary modulation system is corresponding is further used for being not more than RBIR not existing _mRBIR the time, judge whether corresponding modulation system is the lowest-order modulation system, if determine that then minimum value in all code checks to be selected under the corresponding modulation system is as the cooperation code check of this modulation system; Otherwise the cooperation code check of determining corresponding modulation system is 0.

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