DSP: a MAC scheme with double-side scheduling for APON

MAC (medium access control) schemes for ATM-based passive optical network (APON) mostly adopt single-side scheduling in which only optical line termination (OLT) schedules the upstream access order for optical network units (ONUs). In this paper, we propose a MAC scheme called double-side scheduling protocol (DSP) in which both OLT and ONUs participate in the scheduling process. The proposed MAC scheme conforms to the ITU-T recommendation G.983.1. For the proposed MAC scheme, we present grant field format, minislot format, divided slot format, and scheduling algorithm. Through computer simulations, we find out that the cell delay variation (CDV) of real-time services can be improved remarkably using fewer overhead slots than that of MAC schemes adopting CDV control algorithm.