A Modified MRC Receiver for OTFS Systems with Oversampling

Orthogonal Time Frequency Space (OTFS) receivers perform joint equalization of all the symbols in an OTFS frame. We consider delay-time domain Maximal Ratio Combining (MRC) equalization for OTFS systems with receiver oversampling. The associated impairments are Inter-Frame Interference (IFI) and Inter-Block Interference (IBI). The existing Zero-Padding (ZP) approach avoids IFI and IBI but requires high overhead. We propose a Reduced Cyclic Prefix (RCP) and Reduced Cyclic Suffix (RCS) insertion method on the transmitter side that achieves high throughputs. Our approach avoids IFI, and we modify the existing equalizer designed for ZP systems to handle IBI without a significant increase in complexity. We present the Bit Error Rate (BER) simulation results for different oversampling factors and explain the diminishing returns.