Analysis of a Rumor Routing Protocol with Limited Packet Lifetimes

Wireless sensor networks require specialized protocols that conserve power and minimize network traffic. Therefore, it is vitally important to analyze how the parameters of a protocol affect these metrics. In doing so, a more efficient protocol can be developed. This research evaluates how the number of nodes in a network, time between generated agents, lifetime of agents, number of agent transmissions, time between generated queries, lifetime of queries, and node transmission time affect a modified rumor routing protocol for a large-scale, wireless sensor network. Furthermore, it analyzes how the probability distribution of certain protocol parameters affects the network performance. The time between generated queries had the greatest effect upon a network’s energy consumption, accounting for 73.64% of the total variation. An exponential query interarrival distribution with a rate of 0.4 queries/second/node used 25.78% less power than an exponential distribution with a rate of 0.6 queries/second/node. The node transmission time was liable for 73.99% of the total variation in proportion of query failures. Of three distributions, each with a mean of 0.5 seconds, the proportion of query failures using a Rayleigh transmission time distribution was 14.23% less than an exponential distribution and 18.46% less than a uniform distribution. Lastly, 54.85% of the total variation in the mean proportion of time a node is uninformed was a result of the time between generated agents. The mean proportion of time a node is uninformed using an exponential agent interarrival distribution with a rate of 0.005 was 6.59% higher than an exponential distribution with a rate of 0.01

Energy-Efficient Querying of Wireless Sensor Networks

Due to the distributed nature of information collection in wireless sensor networks and the inherent limitations of the component devices, the ability to store, locate, and retrieve data and services with minimum energy expenditure is a critical network function. Additionally, effective search protocols must scale efficiently and consume a minimum of network energy and memory reserves. A novel search protocol, the Trajectory-based Selective Broadcast Query protocol, is proposed. An analytical model of the protocol is derived, and an optimization model is formulated. Based on the results of analysis and simulation, the protocol is shown to reduce the expected total network energy expenditure by 45.5 percent to 75 percent compared to current methods. This research also derives an enhanced analytical node model of random walk search protocols for networks with limited-lifetime resources and time-constrained queries. An optimization program is developed to minimize the expected total energy expenditure while simultaneously ensuring the proportion of failed queries does not exceed a specified threshold. Finally, the ability of the analytical node model to predict the performance of random walk search protocols in large-population networks is established through extensive simulation experiments. It is shown that the model provides a reliable estimate of optimum search algorithm parameters