Adaptive limited DBA algorithm for multi-OLT PON-based FTTH and wireless sensor netwroks

A tree topology based hybrid multi-optical line terminal (OLT) passive optical network (PON) architecture is an inexpensive and highly capable integrated broadband access network. This hybrid multi-OLT PON combines the fiber-to-the home (FTTH) access networks and wireless sensor networks (WSN) in a ubiquitous-City (u-City). A critical issue of a hybrid PON is the difference in the length of generated data packets between FTTH terminals and sensor nodes of WSN. That is why performances of the hybrid multi-OLT PON are not attractive with the existing dynamic bandwidth allocation (DBA) algorithms. In this paper, we propose a new DBA algorithm for the upstream channel of the hybrid multi-OLT PON, called adaptive limited DBA (ALDBA) algorithm. This algorithm uses two different maximum transmission windows for two different service providers to improve the bandwidth sharing efficiency. In the investigation, the performances of the proposed ALDBA scheme were compared with the existing limited service (LS) and Excess-DBA schemes. The simulation results show that the ALDBA scheme provided low packet delay and jitter with high bandwidth utilization than the LS and Excess-DBA schemes.