JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 29, NO. 24, DECEMBER 15, 2011 3777 Saturation Throughput Performance Analysis of a Medium Transparent MAC Protocol for 60 GHz Radio-Over-Fiber Networks George Kalfas, Nikos Pleros, Kostos Tsagkaris, Luis Alonso, and Cristos Verikoukis Abstract—We demonstrate an analytical model for calculating the saturation throughput performance of a medium transparent medium access control (MAC) protocol in 60 GHz radio-over-fiber (RoF) networks. The proposed model incorporates effectively the medium transparent MAC mechanism, assuming a finite number of terminals and ideal channel conditions. It takes into account contention both at the optical and wireless layer, ensuring seam- less and dynamic capacity allocation over both transmission media. This model enables extensive saturation throughput performance analysis for the medium transparent MAC and has been applied to 60 GHz RoF network scenarios considering variable numbers of available optical wavelengths, wireless nodes and serving antenna elements and for two different data rate values, namely 155 Mbps and 1 Gbps. Comparison between the model-based throughput re- sults and respective simulation-based outcomes reveals that our model is extremely accurate in predicting the system throughput. Moreover, it confirms that the proposed medium transparent MAC protocol can effectively operate in high-speed 60 GHz RoF LAN environments. Index Terms—Medium access control (MAC) protocol, medium transparent MAC (MT-MAC), performance analysis, radio over fiber (RoF), 60 GHz local access network (LAN), 60 GHz wireless. I. INTRODUCTION R ADIO-OVER-FIBER (RoF) technologies have drawn at- tention as a highly effective paradigm for bridging the ul- trafast optical buses with the increasingly utilized wireless con- nectivity systems [1]. RoF architectures present a cost effective way for extended range passive optical-wireless networks, con- solidating all required network intelligence in a single central Manuscript received June 08, 2011; revised September 06, 2011, October 04, 2011; accepted October 04, 2011. Date of publication October 14, 2011; date of current version December 14, 2011. This work was supported in part by the Research Project GreenNet (264759) and by the Greek General Secretariat for Research and Technology through Project WisePON. G. Kalfas is with the Technical University of Catalonia, 08034 Barcelona, Spain, and also with the Informatics and Telematics Institute, Center for Re- search and Technology Hellas, GR-54639 Thessaloniki, Greece (e-mail: george. kalfas@estudiant.upc.edu). N. Pleros is with the Department of Informatics, Aristotle University of Thes- saloniki, GR-54124 Thessaloniki, Greece (e-mail: npleros@csd.auth.gr). K. Tsagkaris is with the Department of Digital Systems, University of Piraeus, GR-18352 Piraeus, Greece (e-mail: ktsagk@unipi.gr). L. Alonso is with the Technical University of Catalonia, 08034 Barcelona, Spain (e-mail: luisg@tsc.upc.edu). C. Verikoukis is with the Telecommunications Technological Centre of Cat- alonia, 08860 Castelldefels, Spain (e-mail: cveri@cttc.es). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JLT.2011.2172392 unit, well-known as the central office (CO), and relaxing in this way the complexity, functionality, and cost requirements at the terminal equipment. As a result, the deployment of an array of inexpensive remote antenna units (RAUs) can lead to vast cov- erage wireless networks that optimally combine the mobility and ubiquity advantages of a wireless link with the high speed and long-distance service delivery credentials of fiber-based in- frastructure [2]. The majority of related research has focused so far on ex- ploiting the underlying fiber infrastructure as a passive distribu- tion network used solely for the purpose of long-distance wire- less service delivery. Within this frame, the research emphasis has been on physical layer technologies and architectures for high-capacity RoF network deployments [3]–[6], whereas only a limited number of efforts have attempted the functional con- vergence of the optical and wireless network parts through the realization of dynamic capacity allocation and user mobility concepts [7]–[10]. On the same line, only a small portion of the research carried out so far has been dedicated to medium access control (MAC) layer issues, the main interest being in adapting existing MAC protocol standards, like the 802.11g, to the higher delay metrics of long-distance RoF implementations [11]–[16]. However, this roadmap does not promote the functional inter- facing of the currently distinct operative portfolios of the optical and wireless parts, impeding in this way a seamless and pow- erful optical and wireless network convergence with high-level agility and flexibility potential. RoF advantages become increasingly important as the un- precedented escalation in wireless bandwidth demand drives the need for employment of wireless frequencies capable of deliv- ering very high data rates. A noteworthy example is the license exempt 60 GHz band which has by now been adopted by the industry as the prevailing candidate region for broadband wire- less data transfer. The 60 GHz spectral band has already been enforced in a significant number of emerging standards such as the 802.11ad [17], the 802.15.3c [18]–[20], the WirelessHD [21] and the WiGig [22] protocols. However, the high air propaga- tion losses of this millimeter-wave radio band constitute a sig- nificant constraint in terms of extended range coverage, so that 60 GHz connectivity is inevitably bound to personal area net- working (PAN) applications. 60 GHz communication over RoF physical layer implementations holds the credentials for over- coming this range handicap by employing the fiber-based net- work part for high-distance signal delivery. Moreover, 60 GHz RoF physical layer implementations have reached due maturity for enabling seamless and efficient distribution of multiple 60 0733-8724/$26.00 © 2011 IEEE