Abstract: In multihop communications, nodes that are near a sink tend to become congested as they are responsible for forwarding information from nodes that are farther away. Thus, the closer a sensor node is to a sink, the faster its battery runs out, whereas those farther away may maintain more than 90% of their initial energy. Energy consumption becomes a primary concern in a Wireless Sensor Network. To pursue high energy saving at sensor nodes, a multi mobile collector should traverse the transmission range of each sensor in the field such that each data packet can be directly transmitted to the mobile collector without any relay in heterogeneous WSN. And data packets can be relayed through nodes if packet has emergency info.

Keywords: Energy, WSN, mobile sink, battery, transmission range.