An Agile and Medium-Transparent MAC Protocol for 60 GHz Radio-Over-Fiber Local Access Networks

We present an agile and medium-transparent Medium Access Control (MT-MAC) protocol for seamless and dynamic capacity allocation over both optical and wireless transmission media in 60 GHz broadband Radio-Over-Fiber (RoF) networks. Medium transparency is achieved by means of parallelism between two simultaneously running contention periods and through nesting of wireless user-specific dataframes within Remote Antenna Unit (RAU)-specific optical Superframes. The first contention period reports on the traffic requesting RAUs and decides about the wavelength assignments, whereas the second contention period arbitrates traffic between wireless clients served by the same RAU. Seamless service delivery is completed by RAU-dedicated optical Superframes, each one incorporating multiple user-specific and time-division multiplexed dataframes that are opto-electronically converted at the RAU site and get transmitted wirelessly down to each end-user. The proposed MAC protocol is demonstrated to operate successfully both in RoF-over-bus as well as in RoF-over-Passive Optical Network (PON) architectures requiring only minor variations for getting adapted to the network topology. Its performance for both network topologies is evaluated through simulations for different number of end-users, different loads and network node densities and for bit-rates up to 3 Gb/s, both for a Poisson and for a burst-mode traffic model. Successful operation is demonstrated for all different cases, confirming its agility and showing that extended range 60 GHz LAN areas between wireless users even without line of sight conditions can be obtained. Moreover, the high throughput and low latency values for non-saturated network conditions reveal its potential for transforming broadband 60 GHz picocellular networks into highly effective RoF-enabled 60 GHz Wireless LANs even for high-bandwidth and time-sensitive applications like High-Definition video streaming.