Reliable Data Delivery in Wireless Sensor and Ad Hoc Networks

Abstract

Reliable data delivery is an important feature of mission critical wireless sensing applications. Achieving high degree of reliability is a challenging task due to scarcity of resources in tiny sensor devices in general and energy de ciency in particular. This dissertation investigates inner dynamics of standard reliable data delivery mechanisms based on theoretical frameworks and empirical analysis. To achieve this purpose, we develop realistic wireless channel models to identify the underlying bit-error process of wireless communication in sensor networks. Using knowledge of communication channels and reliable data delivery mechanisms, we propose improved schemes for reliable data delivery in wireless sensor networks which are more energy ef- cient as compared to existing schemes. Compatibility with existing standards is considered as a basic constraint in the design of the new protocols. Each protocol proposed in this work is stochastically modeled and veri ed empirically using a comprehensive set of wireless traces. Our results show up to 40% improvement in energy e ciency. However, we observe that the energy e cient design has its limits as the reduction in energy consumption through energy e cient design does not signi - cantly improve network wide performance measures. Therefore, we conclude that the fundamental problem lies with the coupled energy-sensing design philosophy presently followed in sensor networks. To alleviate this problem, we propose a paradigm shifting concept of decoupling energy sources and sensing in wireless sensor networks. Through theoretical analysis and empirical evaluation, we show that energy decoupling is not only a feasible energy enhancement idea, but also has the potential to completely change the energy conscious design focus of the sensor network community.