A Survey on Mobile Data Gathering in Wireless Sensor Networks - Bounded   Relay
  Most of the wireless sensor networks consist of static sensors, which can be deployed in a wide environment for monitoring applications. While transmitting the data from source to static sink, the amount of energy consumption of the sensor node is high. It results in reduced lifetime of the network.Some of the WSN architectures have been proposed based on Mobile Elements. There is large number of approaches to resolve the above problem. It is found those two approaches, namely Single Hop Data Gathering problem (SHDGP) and mobile Data Gathering, which is used to increase the lifetime of the network. Single Hop Data Gathering Problem is used to achieve the uniform energy consumption. The mobile Data Gathering algorithm is used to find the minimal set of points in the sensor network, which serves as data gathering points for mobile network. Even after so many decades of research, there are some unresolved problems like non uniform energy consumption, increased latency, which needs to be resolved. 
Ms.Rubia.R, Mr.SivanArulSelvan
cs.NI