A propagation-delay-tolerant MAC protocol with adaptive reservation for long propagation delay networks

In order to eliminate the adverse effects of long propagation delay and ensure the quality-of-service (QoS) of high-priority traffic for long propagation delay networks, a new propagation-delay-tolerate MAC (PDT-MAC) protocol with adaptive reservation is proposed. A novel frame structure is designed to maximize the throughput and avoid packet collisions. A piggyback mechanism is also used to reduce the handshakes and thus decrease the overhead of uplink and downlink channels. Meanwhile, a statistic priority access algorithm is adopted to ensure the QoS of high-priority traffic at high traffic load. An adaptive reservation algorithm can coordinate the number of reservation minislots to ensure low reservation collision probability. Simulation results show that the proposed protocol can effectively solve low channel utilization problem caused by long propagation delay, and outperforms FRODT protocol under different propagation delay in terms of throughput, average packet access delay and packet dropping rate. In addition, the results also validate that the QoS of high priority traffic is guaranteed at high traffic load.