Retransmission control for TDMA MAC in energy harvesting wireless sensor networks

Energy harvesting wireless sensor networks ( EHWSN) are characterized by multihop wireless lossy links and resource constrained nodes that are able to harvest small amount of energy from ambient sources such as light, heat or vibration. For TDMA MAC protocols in EHWSN, redundancy and retransmission are two important methods to provide the high end-to-end data reliability. In this paper, for the TDMA MAC protocol, we propose a Reliability-Lifetime Tradeoff Framework (RLTF) for EHWSN to optimize the redundancy transmission number for each link. First, for the redundancy TDMA MAC, we formulate the RLTF as convex programming. By the gradient projection method, we develop a fully distributed algorithm to solve the convex programming. Second, for the retransmission TDMA MAC, we set the retransmission upper bound for each link according to the optimal redundancy number under the redundancy MAC and compute the total communication overhead for the retransmission MAC. Finally, we compare the communication overhead of these two MAC protocols under different channel conditions.