There exist several applications of sensor networks where reliability of data delivery can be critical. While the redundancy inherent in a sensor network might increase the degree of reliability, it by no means can provide any guaranteed reliability semantics. In this paper, we consider the problem of reliable sink-to-sensors data delivery. We first identify several fundamental challenges that need to be addressed, and are unique to a wireless sensor network environment. We then propose a scalable framework for reliable downstream data delivery that is specifically designed to both address and leverage the characteristics of a wireless sensor network, while achieving the reliability in an efficient manner. Through ns2 based simulations, we evaluate the proposed framework.

In this paper, we consider the channel assignment problem in single radio multi-channel mobile ad-hoc networks. Specifically, we investigate the granularity of channel assignment decisions that gives the best trade-off in terms of performance and complexity. We present a new granularity for channel assignment that we refer to as component level channel assignment. The strategy is relatively simple, and is characterized by several impressive practical advantages. We also show that the theoretical performance of the component based channel assignment strategy does not lag significantly behind the optimal possible performance, and perhaps more importantly we show that when coupled with its several practical advantages, it significantly outperforms other strategies under most network conditions.

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The Smart Grid is based on Advanced Metering Infrastructure that mostly relies on Narrow Band Power Line Communication (PLC). In such network, using a single communication interface does not fulfill the primary requirement of 99.99% reading rates and coverage. Hybrid communication, by adding an additional radio interface, is a solution to provide the quality of service required by Smart Grid applications. However, dedicated routing protocols usually operate with a single communication technology. In this paper we present three solutions to enhance the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL)-a well-known routing protocol for smart grid application-for handling multi-interface devices called the Multiple RPL Instances, the Interface Oriented and the Parent Oriented. By means of simulation we show how the network can provide a higher quality of service and a better resilience to failure.