A Comparison of SNDR Maximization Techniques for OFDM

When an orthogonal frequency divisionmultiplexing (OFDM) signal is transmitted through a peak-power limited device, system designers must choose from several options to deal with the large dynamic range problem of OFDM. In this paper, we are interested in comparing i) clipping with gain, ii) modified piece-wise linear scaling (MPWLS) and iii) piece-wise optimized clipping (PWOC) techniques in terms of the signal-to-noise-plus-distortion ratio (SNDR) metric. Existing work has shown that on a per-sample basis, clipping with a judiciously chosen gain and clipping ratio, dubbed uniform optimized clipping (UOC), can maximize the SNDR. Here, we are interested in comparing the performance of UOC with MPWLS and PWOC, two methods that allow for symbol-wise SNDR maximization. Through comparison, we show that the symbol-wise methods provide a slightly higher SNDR compared to UOC. However, this increase in performance comes at the expense of higher complexity.