Parallel dynamic subcarrier and time allocation protocol for long-reach OFDMA-PONs

A new advanced medium access control protocol is described to support 100 km reach access networks, exhibiting the required quality-of-service for next generation passive optical networks based on orthogonal frequency division multiple access. The protocol enables the optical network units (ONUs) to utilize the idle period in each packet transmission time based on their originally granted bandwidth, using the same subcarriers but different time slots to increase the effective transmission bandwidth. The network throughput, end-to-end packet delay and packet loss rate are evaluated by means of both service level agreement and class-of-service differentiation. As a result the packet delay at 80% ONU offered load is less than 3 ms even for the lowest service level ONUs. In addition, the throughput efficiency is 94% of the total network capacity of 40 Gbps, for 100 km long-reach links.