On the efficiency of persistent scheduling for non-periodic real-time services in IEEE 802.16e system

In order to reduce MAP overhead for periodic small-sized services such as voice over IP (VoIP) service, a persistent scheduling scheme has been proposed in IEEE 802.16e/m. Although this persistent scheduling scheme is designed for periodic services, we propose to adopt the persistent scheduling for non-periodic real-time services with small-sized packets by considering the advantage of MAP overhead reduction. Assuming Poisson packet arrivals which show a typical non-periodic property, we mathematically analyze the average delay performance and derive the optimal resource allocation period of the persistent scheduling with a given delay requirement. In this paper, we also compare the average occupied resources per frame between the persistent scheduling and the conventional scheduling both in downlink and uplink. Analysis and numerical results show that for the non-periodic services, the persistent scheduling shows more efficient resource usage than that of the conventional scheduling with a smaller packet size and higher modulation and coding scheme.