Online multi-thread polling algorithm with predicted window size for DBA in long reach PON

Abstract

Passive optical network (PON) has become the vital technology for the next generation access networks. The advancement of optical technology extends the span of the PON from 20 to 100 km. Such an extended PON is known as Long-Reach PON (LR-PON). But the data transmission in the existing LR-PONs suffer from longer propagation delays between the optical line terminal (OLT) and optical network units (ONUs) that degrade the performance of the traditional dynamic bandwidth allocation (DBA) algorithms in the upstream bandwidth allocation of the LR-PONs. This challenge is the main reason to propose a new algorithm which can reduce the effect of longer propagation delay, i.e., due to larger round trip time (RTT), between the transmission of Report messages from the ONUs and reception of Gate messages from the OLT in the LR-PONs. This proposed algorithm allocates some additional bandwidth based on the prediction during the RTT between the OLT and ONUs if the requested bandwidth is less than the maximum bandwidth of the ONUs. The proposed algorithm is a modified version of the existing online multi-thread polling algorithm. The proposed prediction based online multi-thread polling algorithm reduces the end-to-end packet delay and increases the bandwidth utilization and throughput significantly than any other centralized DBA algorithms which are proposed for the LR-PONs.