A soft information calculating method for SC-FDE output symbol

The hard decision symbol of conventional SC-FDE output is not perfect to the posterior SISO decoder of Shannon limit codes such as Turbo code and LDPC codes, which can achieve the Shannon limit performance on condition that the in-out information is soft. In this paper, a soft information calculation method for SC-FDE output symbol is proposed which increases the accuracy of information into the SISO decoder of Shannon limit codes and improves the transmission system. The numerical simulation results also show that the soft output SC-FDE gains an advantage over the hard one and the additional SNR gain can be obtained in frequency selective channel.