Game-Theoretic Spectrum Trading in RF Relay-Assisted Free-Space Optical Communications

TL;DR

This paper introduces a game-theoretic hybrid RF/FSO system that dynamically trades spectrum to improve link capacity and availability during adverse weather, leveraging market equilibrium pricing and RF node diversity.

Contribution

It presents a novel spectrum trading framework for RF/FSO links using game theory, enhancing system performance and robustness under weather impairments.

Findings

Significant capacity improvement with low-traffic RF nodes.

Enhanced link availability during adverse weather conditions.

Diversity benefits increase with more RF nodes involved.

Abstract

This work proposes a novel hybrid RF/FSO system based on a game theoretic spectrum trading process. It is assumed that no RF spectrum is preallocated to the FSO link and only when the link availability is severely impaired by the infrequent adverse weather conditions, i.e. fog, etc., the source can borrow a portion of licensed RF spectrum from one of the surrounding RF nodes. Using the leased spectrum, the source establishes a dual-hop RF/FSO hybrid link to maintain its throughout to the destination. The proposed system is considered to be both spectrum- and power-efficient. A market-equilibrium-based pricing process is proposed for the spectrum trading between the source and RF nodes. Through extensive performance analysis, it is demonstrated that the proposed scheme can significantly improve the average capacity of the system, especially when the surrounding RF nodes are with low traffic loads. In addition, the system benefits from involving more RF nodes into the spectrum trading process by means of diversity, particularly when the surrounding RF nodes have high probability of being in heavy traffic loads. Furthermore, the application of the proposed system in a realistic scenario is presented based on the weather statistics in the city of Edinburgh, UK. It is demonstrated that the proposed system can substantially enhance the link availability towards the carrier-class requirement.