SC-FDE vs OFDM: Performance comparison in shallow-sea underwater acoustic communication

Recent underwater acoustic communication has adopted frequency domain equalization (FDE) for mitigation of multipath interference. If a delay spread of multipath is within a cyclic prefix (CP), FDE is effective in compensating channel distortion. However, long delay waves should be considered when reflected waves arrive from water surfaces, water bottoms, and obstacles in shallow sea environment. If a very long CP is used, it induces a large delay in communication response. This work compares performance of SC-FDE and OFDM with a short CP for long delay multipath. As for QPSK transmission, SC-FDE is less sensitive to inter-block interference (IBI) and inter-carrier interference (ICI) caused by multipath interference. This feature has been verified by received signal distribution and simulation.