A novel dynamic bandwidth allocation algorithm for multi-OLT and multi-wavelength PON-based hybrid networks

A passive optical network (PON) combines multiple service providers' in a ubiquitous city (u-City) without suffering from a bandwidth bottleneck. Multiple optical line terminals (multi-OLT) PON-based hybrid network effectively reduces the computational complexity of data packet processing of multiple service providers having different packet lengths and data rates. However, in the future u-Cities huge number of service providers, e.g., fiber to the home, wireless sensor network, femto networks, and video on demand, will be installed to provide several services. In this regards, only addition of multiple OLTs for multiple service providers are not enough to get the optimum performance from this hybrid network. In this paper, we propose a new dynamic bandwidth allocation (DBA) algorithm for improving the bandwidth sharing efficiency and reducing the time jitter in the upstream channel. Performance of this new DBA algorithm also analyzes for a multi-OLT PON-based hybrid networks where a group of service providers will be connected to an optical network unit (ONU) with individual uplink wavelengths. In contrast, the other groups of service providers will be connected to the other ONUs with different wavelengths and every ONU will be shared by the multiple service providers. In the central office, multiple OLTs will handle the data packets of the multiple service providers. In the proposed DBA algorithm, all the service providers have been divided into two groups on the basis of the maximum packet length of each service provider while all the ONUs are also divided into two groups, i.e., heavily and lightly loaded ONUs, depending on the accumulated data traffics. The simulation results show that the proposed scheme provides less end to end delay and jitter with higher throughput than the conventional PON-based hybrid networks with the limited service (LS) DBA algorithm. The overall throughput of the proposed scheme has been increased more than 80% at the highest offered load of the network than that of the conventional LS scheme.