Client-Weighted Medium-Transparent MAC Protocol for User-Centric Fairness in 60 GHz Radio-Over-Fiber WLANs

Abstract

We present a novel client-weighted medium-transparent medium access control (CW-MT-MAC) protocol with enhanced fairness service delivery properties accompanied by a low-loss remote access unit (RAU) architecture for use in indoor, Gbps-capable, 60 GHz radio-over-fiber (RoF) wireless local area networks (WLANs). Our approach relies on incorporating a client-weighted algorithm (CWA) in the optical capacity allocation mechanism employed in the MT-MAC scheme, so as to distribute the available wavelengths to the different antenna units according to the total number of active users served by each individual antenna. The protocol’s throughput and delay fairness characteristics are evaluated and validated through both simulations and analytic modeling for saturated network traffic operational conditions. In addition, extended simulation-based performance analysis for nonsaturated network conditions and for different end-user distributions, traffic loads, and available optical wavelengths at 1 Gbps data rates is presented. Our results confirm that complete throughput equalization can be achieved even for highly varying user population patterns when certain wavelength availability conditions are satisfied. At the same time, the presented scheme manages to equalize the average packet delays amongst packets generated by all RAUs while concurrently dropping the packet delay variation metric that is essential for quality of service delivery. Finally the proposed RAU design reduces insertion losses by almost 14 dB compared to RAU elements used in MT-MAC-compatible bus networks, extending in this way the number of supported RAUs by an order of magnitude and enabling the formation of extended-reach, high-speed RoF WLANs.