Applied Research, Low-density Polar Checksum

Low density parity check (LDPC) codes have the performance which is nearShannon limit. With advantages of high encoding gain, low decoding complexityand flexible codes, etc., this kind of code has become a hottest topic in the area ofmobile communication. Meanwhile, the study of the beyond third generation (B3G)mobile communication system has gradually entered the initial phase of beingmaterialized. In order to satisfy the need in a variety of services and the high datarate, the high efficient codes have undoubtedly highlighted in the study ofB3G-system. Unfortunately, the most conmmonly used high efficient codes such asTurbo Product Codes (TPC) and Turbo Codes are virtually falling short of meetingthese requirements, while the LDPC codes have been increasingly recoganized byreseachers for their good performance, flexibility and the universal adaptablity.This treatise chiefly fouces on the performance of LDPC codes in B3G.-systemand provides herein the simulation results which suggest that LDPC codes haveapparent advantages over Turbo codes in the said system. We can construct randomcode length and code rate in an acceptable range without puncturing as Turbo codes.This attribute of LDPC codes simplifies the application in the communicationsystem. To correct the burst errors, we need to study the performance of RS codes asan outer code with LDPC codes. The simulation results tell us that the advantage ofRS codes in B3G-system has been covered by extra burst errors, which are farbeyond its error correction limit.Coded modulation is a bandwidth efficient scheme that combines the functionsof coding with modulation. What we come up with in this treatise is a LDPC codedmodulation scheme with 8psk, and its performance has been analyzed over AWGNand Rayleigh fading channels. Both theoretical analysis and simulation results havedemonstrated that this scheme can deliver better performance for bit error rate overeither AWGN or Rayleigh fading channels. Product codes can correct both bursterror and random error. In this case we cannot but highly recommend LDPC product...