An Efficient Data-Gathering Scheme for Heterogeneous Sensor Networks via Mobile Sinks

Typical Wireless Sensor Networks (WSNs) use static sinks to collect data from all sensor nodes via multihop forwarding. This results in the hot spot problem since the nodes close to the sink have a tendency to consume more energy in relaying data from other nodes. Many approaches using mobile sinks have been proposed to prevent this problem, but these approaches still suffer from the buffer overflow problem due to the limited memory capacity of the sensor nodes. This paper proposes an approach in which the mobile sink traverses a subset of nodes. Given the characteristics of wireless communication, such an approach can effectively alleviate the buffer overflow problem without incurring additional energy consumption. To further alleviate the buffer overflow problem, we propose the Allotment Mechanism which allows nodes with different data sampling rates to share their memory and, thus, extend the overflow deadline. Finally, the effectiveness of the proposed approach is verified via the GloMoSim network simulator. The results show that our approach incurs fewer buffer overflows than other data-gathering schemes.