Analysis of bandpass Sigma-Delta conversion in OFDM systems

This paper analyzes the effect of analog-to-digital bandpass Sigma-Delta conversion on the performance of an Orthogonal Frequency Division Multiplexing (OFDM) receiver. OFDM systems and a related simulation model are briefly described. Sigma-Delta characteristics are optimized with respect to overall BER performance. The nonlinear effects of overload are investigated, and a comparison is made with PCM converters. It is shown that minimizing quantization noise power can lead to suboptimal results. A linear model has been developed to estimate the influence of quantization noise on BER performance and it has been validated by means of simulations. Finally a set of minimum performance requirements for Sigma-Delta converters is established.