Eg_ldpc Code In B3g Systems

Wireless communication provides more 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. In the proposals of IEEE 802.11n of next generation WLAN the LDPC code is presented. 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. 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 LDPC codes based on Finite Geometries, specially EG-LDPC codes.By comprision through theoretical analysis such as Density Evolution,EXIT chart and simulation.we found that EG-LDPC codes have very similar performance with random construction LDPC codes ,but much lower encodeing complexity and hardware complexity; meaning while EG-LDPC codes also all Finite Geometry constructed LDPC has it's inherent shortage:we can't construct Fintite Geometry LDPC codes as convenient as random codes,there will be much contraints on it's length and rate .This dissertation has also studied EG-LDPC coeds's application on the B3G scheme,by comparison we found EG-LDPC codes have very excellent performance in B3G link,so we propose EG-LDPC codes must be a very important way in the next B3G optimization and finally instead the current random codes.