Analysis on bit-error characteristics of channel codec in digital mobile communications system

摘要

A calculation algorithm for the bit likelihood in the pi /4 shifted DQPSK (differential quadrature phase shift keying) is proposed, and the bit-error correction ability of the soft decision using the calculated likelihood is indicated. Some frames in which the bit errors are concentrated on the multipath fading channel are investigated, and the required equalizing ability to make the bit-error rate after the decoder less than 10/sup -3/ is shown. The effect of the bit-error concentration on the distribution of the bad frames is considered.