  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.
