定义CRC生成和检验的类(包括函数)
我们在MATLAB中定义一个类(class),包含了CRC生成函数和检验函数(囊括了常用的CRC多项式)
classdef CRCpropertiesCRCbit_LenpolynomialCRCgenCRCdetendmethodsfunction obj = CRC(CRCbit_Len) %(polynomial)obj.CRCbit_Len = CRCbit_Len;switch CRCbit_Lencase 0obj.polynomial = [0];case 1obj.polynomial = [1 1];case 2obj.polynomial = [1 1 1];case 3obj.polynomial = [1 1 1 1];case 4obj.polynomial = [1 0 0 1 1]; % x^4 + x + 1case 5obj.polynomial = [1 0 0 1 0 1];case 6obj.polynomial = [1 0 0 0 0 1 1]; %1000001case 7obj.polynomial = [1 0 0 0 1 1 1 1];case 8obj.polynomial = [1 0 0 1 1 0 0 0 1];case 9obj.polynomial = [1 0 0 0 1 0 0 0 0 1];case 10obj.polynomial = [1 0 0 0 0 1 0 0 0 1 1];case 11obj.polynomial = [1 0 0 0 0 0 0 1 0 0 0 1];case 12obj.polynomial = [1 0 0 1 0 0 0 0 0 0 0 1 1];case 13obj.polynomial = [1 0 0 0 1 0 0 0 0 0 0 0 1 1]; case 14obj.polynomial = [1 0 0 0 0 1 0 1 0 0 0 0 0 1 1];case 15obj.polynomial = [1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1];case 16obj.polynomial = [1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1];case 24obj.polynomial = [1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1];otherwisedisp(["Please add the corresponding polynomial in binary form."]);endobj.CRCgen = crc.generator('Polynomial', obj.polynomial, ...'InitialState', zeros(1, obj.CRCbit_Len), ...'FinalXOR', zeros(1, obj.CRCbit_Len));obj.CRCdet = crc.detector('Polynomial', obj.polynomial, ...'InitialState', zeros(1, obj.CRCbit_Len), ...'FinalXOR', zeros(1, obj.CRCbit_Len));end% generate CRCfunction crcencoded_data = encode(obj, data)crcencoded_data = generate(obj.CRCgen, data); % SourceCoding_Len x No_Active_Usersend% detect CRCfunction [crcdecoded_data, error_detected] = decode(obj, received_data)[crcdecoded_data, error_detected] = detect(obj.CRCdet, received_data); endend
end
程序示例(包含交织和解交织功能)
clc; clear all;
rng('default');
warning('off');K0 = 12; % information bits
K_crc = 4; % crc bits length
N = 16; % coded length (omit here)
% Rate = (K0 + K_crc) / N;Ka = 10; % packet number% Preporcessing:
% interleaver and de-interleaver related: for row vector
interleaver_IDs = randperm(N);
[~, de_interleaver_IDs] = sort(interleaver_IDs);
interlv_func = @(Bits) Bits(:, interleaver_IDs); % Bits could be a matrix with size (packet_num x FEC_Len)
de_interlv_func = @(interlv_Bits) interlv_Bits(:, de_interleaver_IDs);% invoke CRC class
CRC = CRC(K_crc);% Transmission
% information bits
u0 = randi([0, 1], K0, Ka);
% append CRC
u = CRC.encode(u0); % (K0 + K_crc) x Ka
% interleaving
inlv_bits = interlv_func(encodedBits);% omit encoding process and receiver procedure% de-interleaving
deinlv_bits = de_interlv_func(inlv_bits );