A novel hierarchical cooperative data gathering architecture using multiple mobile elements

In this paper, we study the problem of data gathering in wireless sensor networks using cooperative mobile elements. Due to the limit on the physical speed of mobile elements, the existing data gathering schemes that use mobile element can suffer from a high data gathering latency. To address this problem, this paper proposes a new hierarchical and cooperative data gathering architecture (HCDGA) which enables multiple mobile elements to cooperate with each other to collect and relay the data. In HCDGA, two types of mobile elements are used, mobile collectors (MCs) and mobile relay (MR). MCs collect the data from sensors and the MR gathers the data from MCs and delivers the data to the sink. In this work, we first formulate ILP (Integer Linear Programming) optimization problem to find the optimal trajectories of MCs and the MR such that the energy consumption is minimized. Then, we extend the discussion to a cooperative movement scheduling algorithm for determining the optimal movement speeds of MCs and MR such that the minimum gathering latency can be achieved. The simulation results show that HCDGA outperforms multiple travelling salesman problem (mTSP) approach in term of the gathering latency, and the energy consumptions.