Parametric linear precoding for OFDM using Generalized Unitary Rotation

This paper proposes to use parametric unitary transformation, called Generalized Unitary Rotation (GUR), in linear precoder of orthogonal frequency division multiplexing (OFDM) communication system for achieving better performance and flexibility via precoder parametrization and adaptation to the channel characteristics. It is shown that using GUR algorithm it is possible to perform classical, for example Walsh-Hadamard transform (WHT)-based precoding, and derive new classes of parametric linear precoders. Presented simulation results show that any static precoder is not optimal for channel with varying impulse response and signal-to-noise ratio (SNR). Paper provides comparison of well-known precoders with newly proposed ones in terms of error rates and error distributions. Using numerical simulations impact of GUR parameters on the communication system bit error ratio (BER) is measured.