Relay node Placement in partitioned wireless sensor networks with Guaranteed Lifetime

In wireless sensor networks (WSNs), keeping all sensor nodes connected to the sink for collecting data is very important. Nonetheless, when some sensor nodes fail due to emergencies, the connection may be lost and the network may be partitioned into several isolated segments. To restore the connections between each segment and the sink in order to gather the measured data, relay nodes need placing properly in the gap regions. Besides, we usually would like to keep the connectivity for a certain period of time in the real scene. However, obtaining the minimal number, the optimal positions and the optimal transmission power of the placed relay nodes subjected to the network lifetime requirement is NP-hard and heuristics are thus pursued. In this paper, we propose a distributed and energy efficient algorithm, Relay node Placement with Guaranteed Lifetime (RPGL), to reconnect the network while demanding minimal relay nodes subjected to that the network will not be partitioned again due to the failure of the relay nodes within the required time. Simulation results not only verify the theoretical analysis but also show that the number of the relay nodes required is less than the other efficient algorithms in the references.