BER analysis of self-heterodyne OFDM transmission scheme

A self heterodyne system is power inefficient compared to a conventional coherent system, but it has the advantage that simple, low-cost, receivers can be built that are completely immune to any phase noise or frequency offset contributed by the transmitter´s RF carrier. This is of particular importance to multicarrier schemes, such as OFDM, that are much more sensitive to frequency and phase errors then single-carrier schemes. The paper analyzes the performance of self-heterodyne receivers, assuming OFDM is the modulation scheme. We start by deriving the autocorrelation function and power spectral density (PSD) at the output of a square-law device, assuming the phase noise is modeled as a Wiener-Levy process. From this we characterize the BER performance and compare it with simulation of 4,16, and 64-QAM OFDM schemes. Previous statistical analysis of this receiver type has ignored the stochastic nature of the RF phase noise and has neglected to consider the effects of IF instabilities on BER performance.