Energy efficient and low-latency data collection in TDMA-based WSN

Data collection is a basic application of wireless sensor networks, where every sensor node collects data and then forwards data to the Sink node through a multi-hop path. In traditional TDMA scheduling, sensors consume extra energy because of the state transitions which occur numerous times in a TDMA frame. And the longer the length of a TDMA frame, the longer duration of a data collection and the larger of time latency. For the problem mentioned above, Slot Reuse Continuous Link Scheduling problem is proposed in this paper, and then formalized into a cross-layer optimization problem involving the network, medium access control, and physical layers with the objective of maximizing the energy efficiency. We transform the problem into two sub-problems: constructing a data collection tree; joint power control and link scheduling for the data collection tree. Based on an existing data collection tree, we propose an algorithm for allocating a continuous slot and transmission power on every link. Simulation results show that the proposed algorithm can shorten the duration of a data collection process, reduce the number of state transitions and energy consumption, improve network energy efficiency when compared with other existing data collection strategies.