Published Paper Details:

Wireless Sensor Networks (WSN) forms core network of the forthcoming era of IoT. These networks consists of wireless nodes deployed wirelessly with the intent of sensing some physical parameter and sending the measured values to some base station. The transmission is done with the assistance of other nodes in the network working as routers. A sensing node comprises of a microcontroller, a sensing device and radio for transmission. Such a network finds diversified deployment applications and thus presents challenges to the network designers. The most critical parameter to be optimized is the network lifetime and the latency. A most critical aspect for wireless nodes is that these are deployed in large numbers to hostile and harsh conditions and are prone to failures at many times. Also, the nodes are battery driven, executing on low rate and low power consumption (LR-WPAN) protocols designed in such a way that even single Lithium ion battery runs for about 6 months. It is because of these reasons that protocols must be designed carefully to enable evenly battery consumption in all nodes, so as to maximize network lifetime with minimal packet loss. A particular class of wireless sensor Networks is the Real Time WSN in which the time critical needs are to be managed. The contribution of this paper is twofold. It investigates the real time characteristics of the network at MAC Sublayer level in terms of a number of Guaranteed Time Slots (GTS) in the superframe structure. The optimal number of GTS in the superframe is to be chosen in such a way so as to ensure minimum latency and maximum network lifetime. Secondly, it presents a tradeoff of latency and data aggregation at the application layer and gives the relationship between the two in the context of network lifetime. MATLAB is used as a simulation tool and the analytical results presented are in agreement with the simulation model.