Patent ID: 7685501

Claim:
A wireless communication system comprising: a transmitting apparatus having M antennas (M is an integer of 2 or greater) each for transmitting K types (K is an integer of 2 or greater) of signals composed of, at most, M spatially multiplexed signals; and a receiving apparatus having N antennas (N is an integer of 2 or greater) for receiving signals transmitted from said transmitting apparatus; said receiving apparatus comprising: a data reproducer for being supplied with a received signal received by said N antennas and bit likelihood information, detecting a feature of a signal which is spatially multiplexed on a kth signal (k is an integer of 2 or greater) to switch between a first reception mode and a second reception mode, operating in said first reception mode directly calculating likelihoods where each bit is 1 and likelihoods where each bit is 0 from said received signals as first bit likelihood pairs and outputting a reproduced bit string and said first bit likelihood pairs, and operating in said second reception mode for, in a first case in which likelihoods where each bit is 1 and likelihoods where each bit is 0 can be directly calculated from said received signals, directly calculating likelihoods where each bit is 1 and likelihoods where each bit is 0, and for, in a second case in which likelihoods where each bit is 1 and likelihoods where each bit is 0 cannot directly be calculated from said received signals, calculating likelihoods from said bit likelihood information as second likelihood pairs, performing soft decision decoding on said second likelihood pairs, and outputting a reproduced bit string; and a likelihood information calculator for being supplied with said received signals and said first bit likelihood pairs, calculating a physical quantity with respect to smaller bit likelihoods of said first likelihood pairs, and outputting the calculated physical quantity as said bit likelihood information.