  A new technique is presented to design energy-efficient large-scale tracking
systems based on mobile clustering. The new technique optimizes the formation
of mobile clusters to minimize energy consumption in large-scale tracking
systems. This technique can be used in large public gatherings with high crowd
density and continuous mobility. Utilizing both Bluetooth and Wi-Fi
technologies in smart phones, the technique tracks the movement of individuals
in a large crowd within a specific area, and monitors their current locations
and health conditions. The new system has several advantages, including good
positioning accuracy, low energy consumption, short transmission delay, and low
signal interference. Two types of interference are reduced: between Bluetooth
and Wi-Fi signals, and between different Bluetooth signals. An integer linear
programming model is developed to optimize the construction of clusters. In
addition, a simulation model is constructed and used to test the new technique
under different conditions. The proposed clustering technique shows superior
performance according to several evaluation criteria.
