Research And Implementation Of Algorithm For Bicm

It has been recently recognized by Zehavi that the performance of coded modulation over a Rayleigh fading channel can be improved by bit-wise interleaving at the encoder output, and by using an appropriate soft-decision metric as an input to a Viterbi decoder. Unlike trellis coded modulation, bit-interleaved coded modulation has a small free Euclidean distance but large diversity order due to bit interleaving. One goal of this paper is to present BICM in a comprehensive fashion, including the key calculation of the bit metrics, labeling of the signal constellation and the BER performance of BICM compared with TCM. The other is to introduce BICM-ID, an improved scheme for BICM and provide some other schemes to achieve better performance of BICM, such as the method of finding optimized label mappings with BSA, BICM with concatenated decoding and BICM with diversity. Further more, the circuit implementation of BICM-ID is proposed.