Fault Tolerant Wireless Sensor MAC Protocol for Efficient Collision Avoidance

In sensor networks communication by broadcast methods involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.Comment: 14 page

On feedback in network source coding

We consider source coding over networks with unlimited feedback from the sinks to the sources. We first show examples of networks where the rate region with feedback is a strict superset of that without feedback. Next, we find an achievable region for multiterminal lossy source coding with feedback. Finally, we evaluate this region for the case when one of the sources is fully known at the decoder and use the result to show that this region is a strict superset of the best known achievable region for the problem without feedback

Education in India: An Overview of Challenges and Philanthropic Opportunities

India's young population and productive workforce are a remarkable asset to the country, but large gaps in the education sector hinder it from realizing the true potential of this gift. Where are the needs and how can donors help

On achievable rates for multicast in the presence of side information

We investigate the network source coding rate region for networks with multiple sources and multicast demands in the presence of side information, generalizing earlier results on multicast rate regions without side information. When side information is present only at the terminal nodes, we show that the rate region is precisely characterized by the cut-set bounds and that random linear coding suffices to achieve the optimal performance. When side information is present at a non-terminal node, we present an achievable region. Finally, we apply these results to obtain an inner bound on the rate region for networks with general source-demand structures

On Zero-Error Source Coding with Feedback

We consider the problem of zero error source coding with limited feedback when side information is present at the receiver. First, we derive an achievable rate region for arbitrary joint distributions on the source and the side information. When all source pairs of source and side information symbols are observable with non-zero probability, we show that this characterization gives the entire rate region. Next, we demonstrate a class of sources for which asymptotically zero feedback suffices to achieve zero-error coding at the rate promised by the Slepian-Wolf bound for asymptotically lossless coding. Finally, we illustrate these results with the aid of three simple examples