In order to implement wireless sensing and monitoring services at large scale, Internet connection is highly desirable. Particularly, TCP is indispensable for end-to-end connection orientated communication. It is well known that low power and low rate IEEE802.15.4 based Wireless Sensor Networks (WSNs) are vulnerable to the interference from collocated Wireless Local Area Networks (WLAN) utilizing the same un-licensed 2.4GHz frequency band. Such coexistence interference seriously deteriorates the performance of TCP/IPv6 over WSN, resulting in packet losses, disconnections, reduced throughput and so on. This thesis focuses on experimental research on the performance evaluation and improvement of TCP/IPv6 over IEEE 802.15.4 based WSN. In this research, a versatile testbed has been developed and implemented, which consists of off-the-selves and custom built hardware, open source and in-house developed firmware and software. A periodical monitoring/sensing application that uses TCP to transmit data over WSN has been developed and used for performance evaluation when there is various Wi-Fi interference close by. Based on the observations and analysis of our experimental results, several important parameters that impact the TCP packet transmission performance have been identified. Performance improvement technique is proposed to effectively adjust these parameters so as to support periodic monitoring/sensing application with substantial better performance. Extensive experiments have been performed in the testbed to evaluate the performance of WSN packets transmission via TCP over WSN when subjected to different Wi-Fi interference.

Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 138-153). Also available in electronic format on the Internet.

Made available in DSpace on 2014-12-17T14:55:42Z (GMT). No. of bitstreams: 1 patriciaAC_DISSERT.pdf: 1727038 bytes, checksum: 6d92b0a685d31e2550d0b963726e444f (MD5) Previous issue date: 2010-02-19 / This work deals with experimental studies about VoIP conections into WiFi 802.11b networks with handoff. Indoor and outdoor network experiments are realised to take measurements for the QoS parameters delay, throughput, jitter and packt loss. The performance parameters are obtained through the use of software tools Ekiga, Iperf and Wimanager that assure, respectvely, VoIP conection simulation, trafic network generator and metric parameters acquisition for, throughput, jitter and packt loss. The avarage delay is obtained from the measured throughput and the concept of packt virtual transmition time. The experimental data are validated based on de QoS level for each metric parameter accepted as adequated by the specialized literature / Este trabalho trata de estudos experimentais a respeito de conex?es VoIP em redes WiFi 802.11b com mobilidade de um dos usu?rios envolvidos na conex?o de voz e, por conseguinte, na presen?a de handoff. Os experimentos s?o realizados em ambientes indoor e outdoor com foco na medi??o dos ar?metros de desempenho usualmente tidos como indicadores da qualidade de servi?o - QoS em aplica??es VoIP: atraso, vaz?o, jitter, e perda de pacotes. Os par?metros de desempenho s?o obtidos com o aux?lio das ferramentas Ekiga, Iperf e Wimanager que possibilitam, respectivamente, simular uma conex?o VoIP, injetar tr?fego controlado em um ambiente de rede WiFi e medir a vaz?o, o jitter e a perda de pacotes. O atraso m?dio ? obtido analiticamente a partir da vaz?o medida e do uso do conceito de tempo de transmiss?o virtual m?dio de um pacote de voz. A aferi??o da aceita??o dos resultados ? feita com base nos n?veis de servi?os tidos como adequados na literatura para cada uma das m?tricas obtidas nos experimentos