Delay improved Media Access Control for Passive Optical Networks

Passive Optical Networks (PONs) are a promising technology for replacing today´s access networks and to combine them with metropolitan area networks, because they offer high bandwidth and cover wide distances. However, the large distances between the endpoints introduce the problem of a relatively large propagation delay. Traditional Media Access Control (MAC) protocols applied in today´s PONs are not able to handle these propagation delays efficiently. We present a new MAC mechanism specifically tailored for operation in Orthogonal Frequency Division Multiplexing (OFDM) based long-reach PONs. Our approach combines classical polling and random access to join the benefits of both MAC principles to reduce transmission delays. We perform an analytical evaluation of the combined MAC mechanism as well as simulation studies. The simulation studies show that the new MAC approach is able to reduce the minimal transmission delay by up to 63%.