Bidirectional TWDM Optical access network with novel dynamic bandwidth allocation and scheduling algorithm

This paper presents a novel configuration for the optical access systems with dynamic bandwidth allocation (DBA) and the scheduling technique. A new DBA mechanism is proposed which is an improved version of Lightweight Optimal Wavelength Scheduling (LOWS). This algorithm has a provision of multiple priority classes with tunable upstream wavelength. In the presented Modified LOWS (MLOWS) algorithm, the scheduling cycle is segmented equally into two categories, i.e., highest priority and lowest priority information traffic. The surplus transmission capacity from the subscribers having lower bandwidth requirements is assigned to a heavily loaded subscriber optical network unit (ONUs). MLOWS computes the minimum length of the scheduling cycle and allocates that many time slots per cycle to every ONU sequentially. As the demand discrepancy is reduced the requirement for elastic storage buffers is made minimal. The performance of the system architecture and DBA scheme is extensively investigated in terms of quality of service (QOS) parameters. The simulation results show improved network performance in comparison with similar schemes.