Joint topology-transparent broadcast scheduling and MDS erasure coding in multihop TDMA ad hoc networks

In this paper, we study medium-access-control (MAC) protocols with quality-of-service (QoS) support, topology-transparent broadcast scheduling (TTBS), in multihop time-division multiple-access (TDMA) ad hoc networks. TTBS focuses on the QoS provisioning that each node can successfully transfer the same packet to all the other nodes within its communication range simultaneously (broadcast traffic) without the overhead due to the re-computation of transmission schedules when the network topology changes. For broadcast traffic, the MAC layer acknowledgment cannot be applied to provide reliable transmission because the replied acknowledgment packets may suffer conflicts. In order to ensure that all the intended nodes successfully receive the broadcast packet without adopting the MAC layer acknowledgment, TTBS is achieved by transmitting the same packet in all of a nodepsilas assigned slots during a frame (IEEE Trans. Veh. TechnoL, Vol. 52, No. 4, p. 970, 2003). As a result, each node can successfully broadcast only one packet per frame, which is inefficient in terms of bandwidth usage and throughput. To address the problem, we introduce in this paper the use of maximum-distance-separable (MDS) erasure coding to improve the performance of TTBS. By analysis, results for the optimal parameters achieving the best performance are derived for the resulting TTBS. Compared numerical results show that the proposed scheme outperforms the existing one for most of broadcast traffic loads.