Space diversity schemes for STBC-based SC/FDE systems and SC/Pre-FDE systems

In wireless communications, multiple receive antennas can be used with orthogonal frequency division multiplexing (OFDM) or single-carrier (SC) frequency domain equalization (FDE) and frequency domain pre-equalization (Pre-FDE) to significantly improve system capacity and performance. However, the complexity of such combination can be very large because multiple discrete Fourier transform (DFT) blocks, each for one receive antenna, are required to fully take advantage of the space diversity. A receive space diversity architecture was proposed in previous paper for OFDM systems using orthogonal designs. Using this architecture, the number of DFT blocks can be reduced but performance degradation will be introduced. In this paper, we propose two space diversity schemes for SC systems; one uses pre-FDE technique and the other uses FDE and space-time block coding (STBC) technique to compose a multiple-input multiple-output (MIMO) system. Using these schemes, the total number of Fourier transform (FT) blocks can be further reduced but the performance can be significantly improved. Simulation results show that the proposed SC system schemes exceed the corresponding OFDM schemes at high signal-to-noise ratio (SNR).