Structured Ldpc Codes And In Next-generation High-speed Wlan Applications

Wireless communication provides flexible and efficient services than fixed phones, while harder to research. In fact, the mobile channel is one of the most unpredictable channels, so people are seeking for advanced techniques like error control coding.For example; in the proposals of IEEE 802.11n of next generation WLAN the LDPC code is presented.At the present, LDPC code is a hot topic with sparse parity-check matries, the performance is near Shannon limit and complexity is low. Their parallel operation of decoding is easy for hardware implementation. Therefore, it is sure that this kind of codes will be promising in the future mobile communication.Compared with traditional codes which are complex with long searching time, structured LDPC codes constructed by gragh rules or combinational algorithms can reduce the complexity and insure the performance, so they are potential in the future wireless communication system with theoretical value.This treatise has researched on the construction of structured LDPC codes, including EG, BIBD, semi-randomπ-rotation and an approach based on vector-matrix proposed by us and compared random construction and structured construction through theoretical analysis and simulation. We also compared several structured codes. On the other hand, in the approach based on vector-matrix, through several special operations on vector-matrix, we have constructed a sparse'0','1'parity-check matrix with dual diagonal matrix whose structure can easily construct the code. The simulation results have demonstrated the performance of this approach is similar to that ofπ-rotation while the complexity is also higher. This problem is to be solved in the future research.Besides, this treatise has also studied on the coding scheme of two main proposals: WWiSE & TGn Sync and finded that the performance of these LDPC codes is excellent with low complexity. To lower the construction complexity further in TGn Sync proposal, we have optimized its coding scheme.