Hybrid WDM-TDM PON architectures and DWBA algorithms

Passive optical networks (PONs) represent one of the most attractive access network solutions. TDM and WDM techniques are employed in the PON for higher resource efficiency and capacity, which results in TDM PON and WDM PON respectively. Hybrid WDM-TDM PON combines the advanced features of both TDM PON and WDM PON, and provides a more flexible and cost-effective access network solution. We review the current work in the hybrid WDM-TDM PON architectures, dynamic wavelength and bandwidth allocation (DWBA) algorithms and enabling technologies, and present the development and deployment trends from TDM PON to the hybrid WDM-TDM PON. We analyze the deployment problem incurred under physical constraints, and point out there is a need to develop DWBA algorithms with both upstream and downstream traffic scheduling taken into consideration.