Physical-Layer-Aware MAC Schemes for Dynamic Subcarrier Assignment in OFDMA-PON Networks

In this paper, a medium access control (MAC) framework tailored for orthogonal frequency-division multiple access passive optical networks (OFDMA-PONs) is defined which allows exploiting both the subcarrier and time domains in a dynamic and flexible way. A dynamic subcarrier assignment algorithm that respects quality of service by offering decreased average delay is proposed. Moreover, effective methods to improve its performance and reduce its complexity are provided. Additionally, the proposed PON MAC framework for the first time leverages on a cross-layer optimization via adaptive quadrature amplitude modulation (QAM) per optical network unit (ONU). The performance of all schemes is evaluated using computer simulations.