| As an important supporting technology in our smart grid, Power Line Communication(PLC) has being paid more and more attention.Due to widely distributed, low cost and convenient to connected, Power Line Communication has great development potential. Power line is initially used to transmit 50/60 Hz power not used to transmit data. However, compared with wireless communication channel, power line channel has some troubles such as strong noise, transmission attenuation and variable impedance. Select a appropriate channel coding scheme can effectively enhance the signal of anti-interference ability, reduce system bit error rate and improve the reliability of communication system. so the study of power line communication channel coding method has very important significance.LDPC codes can be gotten by information sequence multiplied by generated matrix. Although LDPC check matrix is sparse, the generated matrix is not, and its coding complexity is proportional to the square of code length. It cannot meet low voltage power line communication system with low processing ability.In order to improve the sparsity of generated matrix and reduce the complexity, so the system uses approximate lower triangular matrix encoding method. It can be easily implemented by hardware, and can meet power line communication system for coding performance requirements.Based on European geometry of Galois field, Intersect at the same point of intersection of two straight lines, and they can be constructed of a matrix. Then replaced by the matrix elements of the cyclic permutation matrices(CPM), So you can get a class of quasi-cyclic LDPC codes, Such codes perimeter of at least 8, compared with the circumference of 6, Encoding such a low complexity code, And has a quasi-cyclic structure, In the structures of power line channel system simulation results show. Classic structure with random codes Gallagher 〠Mackay code comparison, LDPC codes constructed with very good error performance,also have the lower platform and fast decoding error convergence rate. |
