卷积码(Convolutional Code),又称为连环码。 卷积码的每个(n,k)码段内的n个码元不仅仅与该码段内的信息元有关,而且与前面m端的信息元有关。通常m为编码存储,用(n,k,m)表示。 1、卷积码的原理 以(2,1,2)卷积码的编码器为例,由移位寄存器、模二加法器及开关电路组成。 起始状态,各级移位寄存器为0,即S1S2S3为000。 S1表
This MATLAB function computes the free distance and the requested number of components of the weight and distance spectra of a linear convolutional code.
The comm.APPDecoder System object performs a posteriori probability (APP) decoding of a convolutional code.
27、rator(贝努利二 进制序列产生器)产生一个 0, 1等概序列,经过Convolutional Encoder(卷积编 码器)对输入的二进制序列进行卷积编码,并用BPSK调制方式调制信号。加入 信道噪声(高斯白噪声)后再经过BPSK解调制后送入Viterbi Decoded Viterbi 译码器)进行硬判决译码。最后经过Error Rate Calculation误码统计)后由Display...
ber2(n,x = rat2;endend ber0 = mean(ber0;ber1 = mean(ber1;ber2 = mean(ber2;semilogy(snr_db,ber0,'b-o',snr_db,ber1,'r-s',snr_db,ber2,'k-p'xlabel('SNR (dB'ylabel('BER'legend('Uncoded','Hard Coded','Soft Coded'title('Performance of convolutional code with rate 1/2'...
This article introduces the basic principles of error-correcting codes, mainly reasearch the principle of the convolutional code encoding and decoding and the algorithms.Through the matlab simulation, we study the performance of convolutional code, especilly the performance of the viterbi decoding with ...
N_bits = 15000; %Number of data bits %number of iterations over which the results are going to be averaged N_iter = 15; for iter = 1:N_iter data = round(rand(N_bits,1));%random data bits %channel coding using rate 1/2 convolutional code: ...
As a general estimate, a typical traceback depth value is approximately two to three times(ConstraintLength– 1) / (1 –coderate). The constraint length of the code,ConstraintLength, is equal to(log2(trellis.numStates) + 1). Thecoderateis equal to(K/N) × (length(PuncturePattern) / ...
6、code 1、卷积神经网络 卷积神经网络(convolutional neural network)是利用模型特性来处理掉输入的波动而获得不变性特征,由LeCun提出,目前广泛的应用于图像数据。 2、基本操作 卷积操作主要是f(x)g(x)在重合区域的积分。 一维卷积 如下图所示,是一维卷积。类似于点积,y=x∗w ,下图的w=[1,0,-1]。这里引...
(codedin,trellis,tbdepth,opmode,dectype,puncpat),codedin为输入编码bit,trellis为生成网格,发送和接收一致,tbdepth为回溯深度,数值设置为(约束长度-1)/(1-码率)×(2~3),opmode,选的tunc,dectype分为软判决和硬判决,codedin为bit信息下为硬判决,codedin为似然比信息输入下为软判决,puncpat为打孔配置,同...