WiMAX Access using Optical Wireless Technology with Heterodyne Detection in Turbulent Atmospheric Channels

The overarching goal of this work is to assess optical wireless technology with heterodyne detection as a potential distributor of WiMAX traffic in metro/access networks. At the transmitter, we consider optical wireless communication via orthogonal frequency division multiplexing (OFDM) as a form of multi-subcarrier modulation (MSM). At the receiver, heterodyne detection is used to produce an output signal at a carrier frequency specified by the WiMAX standard. We incorporate adaptive modulation, atmospheric turbulence, laser linearity and receiver noise to derive symbol error and outage probability expressions, and compare the findings to an analogous direct-detection (DD) system. Results indicate that with local oscillator power P-L = -10 dBm, heterodyne detection (HD) outperforms DD by over 10 dB at error probability P-s = 10(-9) for all modulation formats, in both non-fading and fading channels. This translates to a 3-fold increase in link length over analogous DD systems. Outage probability analysis reveals a similar trend, with HD outperforming DD by 7-15 dB for all cases considered.