Dynamic Source Rate Control for Cache-Based Transport Protocol in Wireless Sensor Networks

Reliability of data transport in low power and lossy networks like Wireless Sensor Networks (WSN) is vital due to its constraint characteristics and high probability of packet loss from wireless environment and congestion. Data caching and transmission rate control mechanisms are independent ways of improving the reliability of transport protocols in WSN as they immediately respond to packet losses in the network. However, these two mechanisms are traditionally designed independently and an appropriate rate control that can potentially improve the performance of cache-based transport protocols has not yet been investigated. In this work, a dynamic source rate control algorithm that utilizes a cache-aware approach was developed wherein cache management policies are employed to notify the relative degree of packet losses and limit the transmission window size. A baseline cache-based transport protocol called DTSN+ is used to implement the rate control algorithm and evaluated under network scenarios that experience packet losses from contention and congestion. The dynamic cache-aware algorithm outperformed other transport protocols in terms of cache utilization by 30%. The algorithm also obtained outstanding throughput, transmission time and fairness performance as compared with the fixed DTSN+ and DTC protocols. This demonstrated that a cache-aware approach can improve the performance of a transport protocol during high levels of packet losses in the network. In the future, these results can serve as an underlying support in designing a new cache-aware congestion control framework that is suitable for transport protocols that employ the use of intermediate caching in WSN.