Marine communities based congestion control in underwater wireless sensor networks

Congestion control in Underwater Wireless Sensor Networks (UWSNs) is an important but challenging issue. TCP performs very poorly in UWSNs due to its inability to distinguish between packet losses due to congestion and those due to channel error. The existing congestion control protocols developed for terrestrial sensor networks cannot be applied to UWSNs because the characteristics of the underwater channel such as high bit error rates, high attenuation and propagation delays, multipath and Doppler distortion have not been considered. In this paper, a biologically-inspired congestion control protocol has been proposed for UWSNs based on the ability of marine communities to terminate with phytoplankton blooms and move the system back to equilibrium between species. The proposed distributed algorithm distinguishes between packet losses due to congestion and those due to high link error rates. It eliminates flow starvation and provides flow fairness. The channel effects of underwater propagation on packet losses are captured, the shadow zones are detected and the throughput of the flows from different nodes at the receiver is restored even with channel fading. Consequently, the system goes back to a stable state, where the different event flows coexist. The theoretical analysis and numerical evaluations show the performance of the proposed congestion control protocol in UWSNs.