Ming Bao

Document Type

Thesis

Date of Award

5-2015

School/College

College of Science, Engineering, and Technology (COSET)

Degree Name

MS in Computer Science

First Advisor

Professor Wei Li, Advisor

Second Advisor

Associate Professor Aladdin M. Sleem

Abstract

Wireless Sensor Networks (WSNs) have attracted attention from both academia and industry since the late 90's. Recent advancements in the technology of microelectromechanical systems (MEMS), the fields of digital electronics, and in wireless communication have resulted in the reductions of both the size and cost of sensor nodes. Even so, there are still some constraints on the performance of WSNs. The two most important constraints are the limited power supply in the sensor nodes and the difficulty in recharging or replacing their batteries. Therefore, reducing the energy consumption of Pensor nodes and optimizing the lifetime of WSNs are crucial. Wireless sensor networks have explored many new protocols, various approaches have been taken to design energy-efficient wireless sensor networks (EEWSNs). In this work, we conducted research on a packet queueing management model that offers different quality of services for packets coming from different sources. This model also incorporate N-policy to minimize excessive switching of transmission radio to conserve battery energy. In our daily life, we often experience waiting in a queue to receive some kind of service. Some customers do not join the queue at the end like other normal customers, and try to cut in the queue hoping to have a shorter waiting time and a higher level of satisfaction. This behavior is called customer interjection. First-come- first-served (FCFS) service discipline is usually assumed in public places like restaurants, banks, airports, and supermarkets. However, customer interjections can still be seen in these places. These interjections can affect the waiting time of other customers in queue. Such interjections may reduce the waiting time of interjecting customers, but increase the waiting time and of others. To control a queueing system, implementing a priority mechanism is a sensible approach. For example, at the airport, customers are categorized in to VIP and general customers. VIP customer has shorter lines and tailored services where as general customer usually stand in line longer and process takes longer to finish too. Priority queue management becomes more important in telecommunication systems also in computer systems (e.g. operating systems) they have been exploited for a long time. Priority queueing control is also used in other production practices. In this research we proposed a queue management model that has a priority queue and a normal queue at the same time. Our proposed model will service priority packets first then turn around to process normal packet until both queues are empty then turn off the radio. This seemingly simple design yields a complex set of balance equations. After solving all the equations with the help of probability generating functions we got the expected queue length for two queues.

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