Adaptive coded modulation based on LDPC codes

In order to resolve the problem of limited spectrum resources and low spectrum utilization rate, we adopted adaptive coded modulation technology based on LDPC codes. We used PEG method to construct the LDPC check matrix and B-P algorithm to decode. In addition, we used the adaptive algorithm based on reliability. We got the modulation and coding scheme thresholds with different reliability request and calculated the average spectrum efficiency. So we verified that the adaptive coded modulation system which adopts LDPC codes can have both good error correction performance and the maximum spectrum utilization rate. The system can adjust to channel diversification dynamically and focus on not only reliability but also efficiency request.