Abstract：In modern communication systems, a channel decoder usually employs the soft input to guarantee a high channel decoding gain. A new soft decision metric for QAM is presented in this paper. Unlike traditional soft decision metric based on minimum Euclidean distance, the proposed metric is based on the bit confidences. Compared to traditional soft decision metric, the one presented in this paper can guarantee the channel decoder performance with less computation complexity. The numerical results applying the proposed method to the DTMB system indicate that the proposed soft decision metric reduces the computation complexity without any performance degradation. These results also show that the proposed metric is a good alternative for soft decision generations.
2009, Vol. 31 
