Low-Complexity Iterative Receiver for Interleaved FDMA (IFDMA) with Cyclic Delay Diversity

Interleaved frequency division multiple access (IFDMA) assigns to each user a set of sub-carriers that are orthogonal to each other. Thus, there is no multiple access interference (MAI) arises during transmission. However, the cost to avoid MAI is to allow for inter-symbol interference (ISI). Thus, the block-iterative generalized decision feedback equalizer (BI-GDFE) can be used as an interference canceller that effectively improves the performance if the frequency selective channel contains rich multi-path components. In order to increase the frequency diversity of the system, cyclic delay diversity (CDD) is applied at the transmitter side. Thus, the performance improvement by BI-GDFE receiver can be enhanced. The computer simulations are performed to compare the BER performance improvement by deploying CDD at the transmitter and using BI-GDFE receiver for an IFDMA system