Reducing the peak-to-average power ratio with companding transform coding in 60 GHz OFDM-ROF systems

To reduce the nonlinear distortion in electrical devices, optical modulators, and transmission fiber, we adopt a companding transform coding technique to reduce the peak-to-average power ratio of the orthogonal frequency division multiplexing (OFDM) signal in an OFDM radio-over-fiber system. By adopting this technique, our experimental results show that the receiver sensitivity at a bit error ratio of 1 × 10
^-3
for a 2.98 Gb/s OFDM signal carried on a 60 GHz optical millimeter-wave after 50 km of standard single-mode fiber transmission is improved by about 0.6, 2.2, and 3.8 dB at launch powers of 0, 6, and 12 dBm, respectively.