A virtual layered space-frequency communication architecture with iterative decoding

In this study, we develop a virtual layered space-frequency communication architecture. This architecture enables the decoding of transmitted OFDM (Orthogonal Frequency Division Multiplexing)-QPSK signals even if the number of antennas at the transmitter is twice the number of antennas at the receiver over multipath fading channels. Furthermore, we propose two detection schemes called "hard replica" and "soft replica." In addition, in order to improve the performance of this architecture, we propose an iteration in which the receiver decodes the detected signals; through such iterations, this architecture can obtain path diversity and achieve high performance. When the transmitter has four antennas and receiver has two antennas, the proposed architecture achieves BER of 8 x 10^-4 using the soft replica at E_b/N₀ = 15 dB. Furthermore, by performing more iterations, it provides additional gains of 3 dB. The performance of the proposed architecture is verified using computer simulations.