M-PSK M-QAM Soft demapping method and apparatus for M-ary PSK and QAM schemes

摘要

Provided is a soft decision bit calculation method for M-PSK and M-QAM schemes. A soft decision detection method according to an embodiment of the present invention detects an evaluation symbol compensated for a channel gain from a received complex symbol, maps the evaluation symbol onto a limited range by using the symmetry of the symbol constellation with respect to each constituent bit, and calculates a soft decision bit value by using the distance between the mapped symbol and the pre-designated symbol. Accordingly, in detecting a soft decision bit for M-PSK and M-QAM schemes, it is possible to calculate the soft decision value with a very small complexity by using a cyclic mapping of the evaluation symbol such that only one distance calculation is required for each constituent bit.