CN100502279C - Mixed code modulation and power distribution method in communication system - Google Patents

Abstract

This invention discloses a method for hybrid encode modulation and power distribution including: 1,at the transmission end, the channel encoded data are separated and reorganized to bit sequences with multiple branches based on the different bit importance, 2, the bit sequences of multiple branches are interleaved separately, 3, the inter leaved bit sequences are modulated separately, 4, distributing power to symbols of the modulated branches, 5, imaging the modulated signals to the physical channel, 6, at the receive end, applying corresponding ways to demodulate the received symbols of different branches to be de-interleaved and de-separated so as to get the data sent by the transmission end.

Description

Hybrid coding modulation and power distribution method in the communication system

Technical field

The present invention relates to a kind of hybrid coding modulation and power distribution method with higher-wattage efficient and spectrum efficiency.

Background technology

Can predict multimedia services such as audio frequency, video, image and Internet will become the dominant traffic of future mobile communications, and these business obviously improve (these professional peak traffic speed are greater than 20Mbps) for the requirement of transmission of radio links ability, in the case, for the transmission of high-rate data, the spectrum efficiency of raising system, multi-system modulation system have obtained to use widely.Yet the raising of multi-system modulating system spectrum efficiency exchanges for by sacrificing power efficiency.When signal is subjected to the infringement of noise and interference, the received signal error probability also will increase thereupon.Though can adopt amplitude-phase associating keying (APK) mode to overcome the problems referred to above, effect is also not obvious in actual applications, particularly along with the raising of order of modulation, the degree of mis-behave is aggravated.

On the other hand, the signal transmission environment of mobile communication system is very abominable.Channel coding technology is the effective ways that improve the system transmissions data reliability in the mobile communication, makes receiver can detect and correct the signal errors that transmission medium brings.For the transmission of high-rate data, improve spectrum efficiency, guarantee the reliability of transmission simultaneously, high order modulation and chnnel coding become the hot spot technology of current research in conjunction with problem.Many researchers have carried out extensive and deep research to high order modulation and chnnel coding in conjunction with problem, mainly comprise trellis-coded modulation (TCM, trellis code modulation) technology, block encoding modulation (BCM, block codedmodulation) technology, multistage coding (MLC, multilevel coding) technology, Bit Interleave coded modulation (BICM, bit-interleaved coded modulation) technology.Yet the performance of above-mentioned four kinds of methods when combining with high order modulation is also not fully up to expectations, also has been subjected to certain restriction thereby it is used in practice.Seek a kind of modulation of practicality and high efficiency and the associated methods of chnnel coding associated methods, particularly high order modulation and coding and have crucial meaning.

Summary of the invention

At problems of the prior art, the present invention proposes a kind of hybrid coding modulation and power distribution method that extensively is suitable for, separate reorganization for coded-bit according to certain principle, adopt the combination of multiple modulation system and distribute different power, thereby have power efficiency and higher frequency efficiency preferably.

According to the present invention, hybrid coding modulation and power distribution method in a kind of communication system are provided, comprise step:

(1), will separate the bit sequence that is reassembled as a plurality of branch roads through the difference of the data based coded-bit importance after the chnnel coding at transmitting terminal;

(2) bit sequence that separates a plurality of branch roads after recombinating is carried out Bit Interleave respectively;

(3) bit sequence of a plurality of branch roads after interweaving is modulated respectively;

(4) to the allocation of symbols power after the different branch modulation;

(5) signal map after will modulating is to physical channel;

(6) at receiving terminal, adopt corresponding demodulation mode to carry out demodulation to the symbol of the different branch that receives, and a plurality of tributary signals after the demodulation are carried out deinterleaving, separate and separate reorganization, thereby obtain the data that transmitting terminal sends.

In the present invention, according to bit significance coded-bit is separated reorganization, and handle respectively, comprise and adopt different modulating mode, distribution different capacity, distribution different channels, and along with the variation of channel quality, adaptively changing combinations of modulation and power division.Specifically, through after the chnnel coding,, and handle respectively, comprise and adopt different modulating mode, distribution different capacity, distribution different channels according to coded-bit importance difference in transmitting terminal raw information.For example, at the different modulation system of bit employing of different importance, for the high information bit lower order modulated of importance, for the low check bit higher-order modulation of importance.And, distribute different transmitting powers at transmitting terminal according to certain principle, with further raising performance according to the importance difference of bit.In addition, after variations, can adopt different coded modulation combination and power distribution method, can further improve throughput of system according to certain self adaptation principle.

The method according to this invention is separated reorganization at the height of the importance of different bits after the chnnel coding with it, and the bit of different importance is adopted the different modulation systems transmitted power different with distribution.Keeping having reduced the influence of high order modulation effectively under the constant condition of data rate, thereby improving the error performance and the power efficiency of whole system systematic function.On the other hand, this method is selected different coded modulation combination and power division according to the variation of channel quality, can further improve systematic function.In addition, the present invention reduces interleave depth when guaranteeing lower complexity, also makes its hard-wired complexity reduce.

Description of drawings

Fig. 1 shows the schematic diagram according to transmitting terminal of the present invention.

Fig. 2 shows the schematic diagram according to receiving terminal of the present invention.

Embodiment

In the present invention, transmitting terminal separated it according to the importance of different bits through the bit sequence after chnnel coding and the rate-matched (punching, repetition or zero insertion) be reassembled as a plurality of branch roads, each branch road bit sequence is carried out Bit Interleave respectively, also can adopt existing multiple deinterleaving method here.

Handle respectively at the bit sequence that separates a plurality of branch roads after recombinating, comprising:

(1) the different branch bit sequence is adopted the different modulating mode, for example adopt the low-order-modulated mode for the high bit of importance, the bit that importance is low adopts high-order modulating.

(2) power different to the different branch signal allocation for example distributes higher transmitted power for the higher bit sequence of importance, distributes low transmitted power for the lower bit sequence of importance.

(3) with the different branch signal allocation in the different gains channel, be distributed in gain for the higher bit sequence of importance and transmit on the good channel, be distributed in the poor slightly channel of gain for the lower bit sequence of importance

In the present invention, can adopt the combination in any of mode (1)～(3), and can adopt existing multiple power distribution method to distribute power.

Can adopt different coded modulation combinations to encode as stated above and modulate at different channel quality (can by measure obtain), when channel condition is good, adopt the relative more coded modulation combined method of high-order further to improve throughput, when bad channel conditions, guarantee communication quality by reducing order of modulation.

In receiving terminal, carry out demodulation, deinterleaving accordingly, separate and separate reorganization, separate rate-matched and decode operation according to the different operating of transmitting terminal.

Describe with reference to the accompanying drawings and in conjunction with the preferred embodiments at the bit sequence that separates a plurality of branch roads after recombinating and adopt different modulating mode and the scheme of distributing different power respectively.

Fig. 1 is the schematic diagram of transmitting terminal of the present invention.After receiving information, carry out cyclic redundancy check (CRC) from information source.Chnnel coding among Fig. 1 can be any coded system that can distinguish importance by bit.Candidate's modulation system can select to plant arbitrarily modulation system, for example { BPSK, QPSK, 16QAM, 64QAM, 128QAM} from the low order to the high-order.According to shown in Figure 1, at transmitting terminal, the bit sequence after information bit process chnnel coding and the rate-matched is { c _i.Bit after the rate-matched separates according to the height of different bit significance and is reassembled as L bit sequence, is respectively

This process is finished by separating recombination module, and can select recombination method flexibly at different coding mode and rate-matched mode.After the bit sequence of L branch road interweaved through interleaver respectively, become for

The different branch bit sequence is adopted different modulation systems, and the sequence after the modulation is Then, the signal of not going the same way is distributed power according to certain principle, for example for the more power of the allocation of symbols after the low-order-modulated, the allocation of symbols less power after the high order modulation.At last, through sending after the remaining transmission processing.

In the present invention, how separate recombination module distinguishes importance and need decide according to concrete coding and rate-matched scheme.For example adopt 1/3 Turbo coding at transmitting terminal, coded-bit is separated into the information bit branch road, the first check digit branch road and the second check digit branch road, be one tunnel (because its importance is identical) again with two-way check digit branch combinations, form two branch roads that importance is different like this after separating recombination module: information bit branch road importance is higher, and check digit branch road importance is taken second place.Perhaps, adopt 1/3 convolution code at transmitting terminal, coded-bit is through after the rate-matched, be separated into the information bit branch road, the first check digit branch road and the second check digit branch road, form three branch roads that importance is different like this after separating recombination module: information bit branch road importance is higher, and the second check digit branch road importance is taken second place, and the first check digit branch road importance is minimum.

Fig. 2 is the schematic diagram of receiving terminal of the present invention.The data that received respectively through Data Detection, separate mapping, symbol reorganization, demodulation, deinterleaving, separate and separate to recombinate, separate rate-matched and decode procedure and finish recovery initial data.

Specifically, receive data through channel estimating, detect, separate mapping after, according to data arrangement different in the receiving terminal testing process symbol is recombinated, make each circuit-switched data after the reorganization corresponding, and then separate the mediation channel decoding according to different modulation systems with the corresponding modulation system of transmitting terminal.

For different modulation systems, the soft bit values of I road, Q road signal can be obtained by same computing formula, that is:

$\mathrm{LLR}\left(b_{I,k}\right)=\frac{{\left|G_{\mathrm{ch}}\left(i\right)\right|}^2}{4}\{\underset{\mathrm{\α}\∈S_{I,k}^{\left(0\right)}}{\min }{|y\left[i\right]-\mathrm{\α}|}^2-\underset{\mathrm{\α}\∈S_{I,k}^{\left(1\right)}}{\min }{|y\left[i\right]-\mathrm{\α}|}^2\}---\left(1\right)$

$\mathrm{LLR}\left(b_{Q,k}\right)=\frac{{\left|G_{\mathrm{ch}}\left(i\right)\right|}^2}{2{\mathrm{\σ}}^2}\{\underset{\mathrm{\α}\∈S_{Q,k}^{\left(0\right)}}{\min }{|y\left[i\right]-\mathrm{\α}|}^2-\underset{\mathrm{\α}\∈S_{Q,k}^{\left(1\right)}}{\min }{|y\left[i\right]-\mathrm{\α}|}^2\}---\left(2\right)$

{ G wherein _Cb(i) } be channel condition information, y[i]=r[i]/G _Ch(i), r[i] be received signal, b _{I, k}, b _{Q, k}K bit representing transmitting terminal I road, Q road signal respectively.For different modulation systems, (1) formula and (2) formula are general, just choose according to different constellation point at different modulation system α.

Soft bit information after the demodulation can carry out channel decoding at the channel coding method of transmitting terminal through after deinterleaving, separating rate-matched.

It should also be noted that, the position of bit separation recombination module is variable, that is to say, both can separate the reorganization operation and also can separate reorganization after rate-matched before rate-matched, the principle that should follow is exactly that the different coded-bit that makes can separate according to different importance is simple and effective here as far as possible.

At last, at different channel conditions several alternative coded modulation combined methods can be arranged. being that different branch selects the modulator approach of relative high-order to improve the validity of communication when channel condition is good, is that different branch selects the modulator approach of relative low order to guarantee the reliability of communication in the time of bad channel conditions.

This method is conceived at the importance of different coding bit it be separated reorganization, and the bit that separates after recombinating is adopted different modulation system and power distribution method.On the other hand, along with the variation of channel quality, combination of this method adaptively changing coded modulation and power division.This method can effectively reduce order of modulation and raise to the influence of systematic function when guaranteeing high transfer rate.In addition, playing the effect that the space interweaves owing to carry out bit separation, this method can also reduce the degree of depth that interweaves when not influencing performance, thereby has made things convenient for the hardware realization.

Claims (10)

1, modulation of the hybrid coding in a kind of communication system and power distribution method comprise step:

(1) when transmitting terminal adopts 1/3 spy to broadcast coding, to be separated into information bit branch road, the first check digit branch road and the second check digit branch road through the difference of the data based coded-bit importance after the chnnel coding, with two-way check digit branch combinations be importance identical a road, thereby form higher information bit branch road and the lower check digit branch road of importance of importance;

(2) bit sequence that separates a plurality of branch roads after recombinating is carried out Bit Interleave respectively;

(3) bit sequence of a plurality of branch roads after interweaving is modulated respectively;

(4) to different branch signal allocation different capacity, send for the bigger transmitted power of signal allocation of the higher branch road of importance, send for the signal allocation smaller transmission power of the lower branch road of importance;

(5) with the different branch signal map to the different physical channel of gain, for the signal of the higher branch road of importance in the bigger channel of gain, for the signal of the lower branch road of importance in the relatively poor channel of gain;

(6) at receiving terminal, adopt corresponding demodulation mode to carry out demodulation to the symbol of the different branch that receives, and a plurality of tributary signals after the demodulation are carried out deinterleaving, separate and separate reorganization, thereby obtain the data that transmitting terminal sends.

2, method according to claim 1 wherein also comprises step in the step (1):

After data after the chnnel coding are carried out rate-matched, separate reorganization again.

3, method according to claim 1, wherein step (6) also comprises step:

Carry out rate-matched and channel decoding to separating the bit sequence that separates after recombinating.

4, method according to claim 1, wherein step (3) also comprises step:

The different branch signal is adopted the different modulating mode, adopt the modulation system of lower-order, adopt the modulation system of higher-order for the bit sequence of the lower branch road of importance for the bit sequence of the higher branch road of importance.

5, method according to claim 4 also comprises step:

When the channel condition of described communication system is better, increase the order of modulation of the bit sequence of these branch roads respectively;

When the channel condition of described communication system is relatively poor, reduce the order of modulation of the bit sequence of these branch roads respectively.

6, method according to claim 4 also comprises step:

When the channel condition of described communication system is better, increase the order of modulation of the bit sequence of part branch road;

When the channel condition of described communication system is relatively poor, reduce the order of modulation of the bit sequence of part branch road.

7, modulation of the hybrid coding in a kind of communication system and power distribution method comprise step:

(a) when transmitting terminal adopts 1/3 convolution code, coded-bit is through after the rate-matched, be separated into information bit branch road, the first check digit branch road and the second check digit branch road, thereby form the second check digit branch road and the first minimum check digit branch road of importance that higher information bit branch road, the importance of importance is taken second place;

(b) bit sequence that separates a plurality of branch roads after recombinating is carried out Bit Interleave respectively;

(c) bit sequence of a plurality of branch roads after interweaving is modulated respectively;

(d) to different branch signal allocation different capacity, send for the bigger transmitted power of signal allocation of the higher branch road of importance, send for the signal allocation smaller transmission power of the lower branch road of importance;

(e) with the different branch signal map to the different physical channel of gain, for the signal of the higher branch road of importance in the bigger channel of gain, for the signal of the lower branch road of importance in the relatively poor channel of gain;

(f) at receiving terminal, adopt corresponding demodulation mode to carry out demodulation to the symbol of the different branch that receives, and a plurality of tributary signals after the demodulation are carried out deinterleaving, separate and separate reorganization, thereby obtain the data that transmitting terminal sends.

8, method according to claim 7, wherein step (c) also comprises step:

The different branch signal is adopted the different modulating mode, adopt the modulation system of lower-order, adopt the modulation system of higher-order for the bit sequence of the lower branch road of importance for the bit sequence of the higher branch road of importance.

9, method according to claim 8 also comprises step:

When the channel condition of described communication system is better, increase the order of modulation of the bit sequence of these branch roads respectively;

When the channel condition of described communication system is relatively poor, reduce the order of modulation of the bit sequence of these branch roads respectively.

10, method according to claim 8 also comprises step:

When the channel condition of described communication system is better, increase the order of modulation of the bit sequence of part branch road;

When the channel condition of described communication system is relatively poor, reduce the order of modulation of the bit sequence of part branch road.

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