Performance analysis of hybrid FSO/RF communication systems with Alamouti Coding or Antenna Selection

TL;DR

This paper introduces a novel hybrid FSO/RF communication system with relay assistance, analyzing the performance of Alamouti Coding and Antenna Selection under atmospheric turbulence and pointing errors, providing closed-form BER and outage probability expressions.

Contribution

First investigation of Alamouti Coding and Antenna Selection in a hybrid FSO/RF system with derived closed-form performance metrics.

Findings

A slight performance difference between AC and AS schemes.

AS is recommended due to lower complexity and power consumption.

System significantly improves reliability for long-range mobile applications.

Abstract

In this work a novel dual-hop relay-assisted hybrid Free Space Optical / Radio Frequency (FSO / RF) communication system is presented. In this system, RF signal is transmitted from two antennas, and then forwarded by a single antenna relay through FSO channel. This is the first time that performance of using Alamouti Coding (AC) or Antenna Selection (AS) at the transmitter of a hybrid FSO / RF system is investigated. FSO link has Gamma-Gamma atmospheric turbulence, and in order to get closer to the actual results, the effect of pointing error is also considered. For the first time closed-form expressions are derived for Bit Error Rate (BER) and Outage Probability of the proposed system and validated through MATLAB simulations. Results indicate that in this structure, there is slight performance difference between AC and AS schemes. Hence due to more complexity, power consumption and latency of AC, AS is recommended. Dual-hop, hybrid FSO / RF system significantly improves performance and reliability of the system, and is particularly suitable for long-range applications that direct RF communication between source and destination is not possible. Considering these advantages this structure is particularly suitable for mobile communications which has power and processing limitations.