A loop-back framing architecture with simple dynamic bandwidth allocation algorithm for WDM-PON

Abstract

This paper describes a WDM-PON architecture to provide diverse broadband services. Optical access network, such as Fiber To The Home (FTTH) network, needs simple and cost-effective architecture. We propose a Loop-Back WDM-PON(LPB-PON) architecture with adaptive frame structure and corresponding framing procedure. Firstly, we propose a novel LPB-PON scheme. LPB-PON employs reflective modulators: continuous light from the central office is sent downstream and reflected back to the central office by the Optical Network Unit (ONU), after modulation with the data signal. In this way, the light source remains wavelength-independent, and therefore can be installed anywhere in the network. Also, we propose a novel Simple Polling with Subscriber Level(SPSL) scheme that allows the upstream bandwidth to be shared among many subscribers. With business customers preferring guaranteed bandwidth services and residential customers preferring low-cost services, our scheme can satisfy both groups of subscribers. We modelled the proposed SPSL scheme using the OPNET simulator and the simulation results show that the proposed scheme is suitable for guaranteed bandwidth services for diverse applications. Moreover we can contain the delay variation to certain level for time-sensitive traffics such as voice and interactive multimedia services.