Engineering Commons^™

Channel-Predictive Link Layer Arq Protocols In Wireless Networks, Huseyin Dogukan Cavdar

Theses

Communication performance over a wireless channel should be considered according to two main parameters: energy and throughput. The reliable data transfer is a key to these goals. The reliable node-to-node data transfer is performed by link layer protocols. One prominent approach is Automatic Repeat Request (ARQ) protocol. The traditional ARQ protocols attempt to recover the erroneously transmitted frames by retransmitting those frames, regardless of the channel state. Since this channel state unaware behaviour may cause unnecessary retransmissions, traditional ARQ protocols are expected to be energy inefficient. Some ideas have been proposed such as stochastic learning automaton based ARQ, and channel …

Performance Of Multi-User Codes In Wireless Communications, Muhammad Tauseef Ulislam

Theses

Multi-user codes are a widely used in transmitting user data from base station to mobile station and vice versa. In wireless communications a signal received by a mobile station goes through different fading channels resulting. These multi-paths add constructively and destructively with different delays and attenuation at the mobile station. The autocorrelation and cross correlation properties of the Multi-user codes play a significant role in extracting the user data from the signal corrupted by multipath fading channel.

The thesis presents a comparison of different Multi-user codes based on their autocorrelation and cross correlation properties. These codes are passed through a …

Low Interference Routing For Wireless Ad-Hoc Networks, Mohit Gupta

Theses

In this thesis the primary focus is on the problem of interference between messages. The thesis discusses why the messages are blocked in a system? How adding a message impacts the cost of all other available links, which can be established in the system.

This thesis analyzes how the availability of channels, increase in number of nodes and increase in the transmission range help in increasing the number of messages that can be handled in the network. It is also analyzes how critical is the selection of the maximum transmission range MTR, transmission range TR and required transmission range RTR. …

Detecting Malfunction In Wireless Sensor Networks, Pablito C. Lake

Theses

The objective of this thesis is to detect malfunctioning sensors in wireless sensor networks. The ability to detect abnormality is critical to the security of any sensor network. However, the ability to detect a faulty wireless sensor is not trivial. Controlled repeatable experiments are difficult in wireless channels. A Redhat Linux. 7.0 Wireless Emulation Dynamic Switch software was used to solve this problem.

Six nodes were configured with a node acting as a base station. The nodes were all part of a cell. This means that every node could communicate with all other nodes. A client-server program simulated the background …

Comparative Studies Of Network Traffic In Actual And Emulated Wireless Networks, Curtis Salley Jr.

Theses

Wireless networks are becoming more popular in all types of environments from home office, to business infrastructure, to mobile computing. As more of these networks flourish, so does the attraction for hackers. The thesis examines the bandwidth of wireless networks and the effects of intrusions in three different scenarios. First, it looks at a wireless network that is connected to a wired infrastructure. Next, the thesis examines a wireless ad hoc network and how bandwidth plays a valuable part in the communication with neighboring nodes. And finally, the thesis attempts to simulate a wireless network by using a bandwidth configuration …

Tracking The Path Of A Mobile Radioactive Source Using A Wireless Sensor Network, Nipa Shah

Theses

This report describes several experiments used to characterize and test a network of radiation sensors. The purpose of these tests is to assess the feasibility of using these sensors to detect and track radioactive sources in a large field, as in a battlefield or on a military campus. Simulated radiation measurements are used to compare the result of radiation detection accuracy in tracking the moving target and to find its path as early as possible. This is done via changing the number of sensing nodes deployed (deployment density), as well as the models of the detectors. This thesis describes algorithms …

Sub-Segment Based Transport Layer Protocol For Wireless Medium, Som Sengupta

Theses

This thesis discusses the techniques to improve the TCP over wireless. The loss-intensive wireless communication results in high retransmission rates to recover lost packets and bandwidth consumption. In addition, the retransmitted segments have significant chance of being dropped. To make the retransmission process more granular, large segments at the transport layer (540 bytes, by default) can be subdivided into smaller sub-segments. This document introduces a split TCP based solution and describes how to produce a series of smaller-sized segments that share the same transport layer header. A new header format is introduced to support the transmission of smaller segments …