OFDM RoFSO Links with Relays Over Turbulence Channels and Nonzero Boresight Pointing Errors

摘要

In the last few years, the radio on free space optics (RoFSO) technology that involves effective wireless transmissions of multiple radio frequency (RF) signals via free space optical (FSO) links, has drawn great research and commercial interest. However, its deployment suffers from atmospheric turbulence and pointing errors effects that strongly degrade the performance of such optical wireless links. In order to combat these impairments, in this work, we investigate the performance of various realistic RoFSO scenarios that may employ orthogonal frequency-division multiplexing (OFDM) scheme with Quadrature Amplitude Modulation (QAM) format and Decode and Forward (DF) relay node(s) over weak to strong turbulence channels emulated through the very accurate recently launched Malaga or M-distribution model along with the presence of various nonzero boresight pointing errors effects with different jitters for the elevation and the horizontal displacement modeled through the suitable Beckmann distribution. Under these conditions we extract closed-form mathematical expressions for the crucial performance metrics of the Outage Probability (OP) and the Average Bit Error Rate (ABER) of the examined RoFSO implementations with DF relays. Proper numerical results that are validated through the corresponding simulations are provided and demonstrate the accuracy of our extracted expressions along with the usefulness of serial DF relay-assisted multi-hop configurations as an effective method to broaden the coverage of the optical wireless links.