Topology Control Schema for Better QoS in Hybrid RF/FSO Mesh Networks

• Published in: IEEE transactions on communications Vol. 60; no. 5; pp. 1398 - 1406
• Main Authors: Awwad, O., Al-Fuqaha, Ala, Khan, B., Brahim, G. B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Communication networks; Communications networks; Delay; Exact sciences and technology; Free space optics; Hybrid RF/FSO; Lagrangian relaxation; linear programming; MANETs; Meetings; Network topology; Networks; Operation, maintenance, reliability; Optical telecommunications; Optical wireless; particle swarm optimization; Peer to peer computing; QoS; Quality of service; Radio frequencies; Radio frequency; Radiocommunications; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Topology; topology control; Transceivers; Transmission and modulation (techniques and equipments); Transmitters; Transmitters. Receivers; Wireless optical communications; Optical telecommunication; Wireless telecommunication; Information rate; Iterative method; linear programming; Communication technology; Transceiver; Biomimetics; QoS; Lagrangian relaxation; Relaxation method; Hybrid model; Delay time; Free space optics; topology control; Lagrangian method; Mobile radiocommunication; Meshed network; particle swarm optimization; Radiofrequency; Information transmission; Integer programming; Optical beam; Free space propagation; Hybrid RF/FSO; Optimal solution; Heuristic method; Telecommunication network; MANETs; Wireless network; Service quality
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2012.12.110069

The practical limitations and challenges of radio frequency (RF) based communication networks have become increasingly apparent over the past decade, leading researchers to seek new hybrid communication approaches. One promising strategy that has been the subject of considerable interest is the augmentation of RF technology by Free Space Optics (FSO), using the strength of each communication technology to overcome the limitations of the other. In this article, we introduce a new scheme for controlling the topology in hybrid Radio-Frequency/Free Space Optics (RF/FSO) wireless mesh networks. Our scheme is based on adaptive adjustments to both transmission power (of RF and FSO transmitters) and the optical beam-width (of FSO transmitters) at individual nodes, with the objective of meeting specified Quality of Service (QoS) requirements, specifically end-to-end delay and throughput. We show how one can effectively encode the instantaneous objectives and constraints of the system as an instance of Integer Linear Programming (ILP). We demonstrate that the technique of Lagrangian Relaxation (LR), augmented with iterative repair heuristics, can be used to determine good (albeit sub-optimal) solutions for the ILP problem, making the approach feasible for mid-sized networks. We make the proposed scheme viable for large-scale networks in terms of number of nodes, number of transceivers, and number of source-destination pairs by solving the ILP problem using a Particle Swarm Optimization (PSO) implementation.