Low Computational Algorithm for Space Time Coded System with LDPC codes

In wireless communication, it requires a high speed transmission with various services and a high reliability. To satisfy these needs, the LDPC code and STC technologies are actively researched. Concatenating LDPC codes to the transmit diversity achieves the coding gain from the concatenated LDPC codes and the diversity gain from the transmit diversity. In this paper, to feed the soft values to LDPC decoder from multiple transmitter and receiver antennas, we propose on effective algorithm for calculation of soft values from multiple receiver antennas based on LLR. We show that maximum 60% of computational complexity is reduced with a little loss of performance.