[CCoE Notice] PhD Dissertation Presentation

[Abercrombie, Irene F]

PhD Dissertation Defense

TOWARD RELIABLE AND ROBUST WIRELESS PERSONAL AREA NETWORKS

Guanbo Zheng

Date: Wednesday, July 17th, 2013

Location: ECE Small Conference Room, N358
            Time: 10:00 am

Committee Chairs:
Dr. Zhu Han & Dr. Rong Zheng

Committee Members:
Dr. Yuhua Chen
Dr. Jiming Bao
Dr. Bo Sun
Dr. Cunqing Hua



In recent years, wireless personal area networks (WPANs) have been widely deployed to replace cable
connections and provide low power, low cost wireless connectivity to facilitate seamless operation
among wireless devices centered around an individual person. However, pervasive deployment of
WPANs has introduced a lot of challenging problems on coexistence and resource provisioning. First,
commercial‐of‐the‐shelf (COTS) WPAN devices typically provide limited information regarding the
current condition of wireless channels. The lack of detailed PHY knowledge usually leads to misinformed
decisions and under‐utilization of available resources. In this dissertation, we revisit the issue of link
quality prediction in IEEE 802.15.4 low rate WPANs analytically and experimentally. By deciphering LQI
readings available in Zigbee radios with CC2420 chipset, we demonstrate for the first time that LQI truly
reflects the signal‐to‐noise ratio (SNR) at the receiver. Furthermore, to predict the instantaneous link
quality, we develop an inference model under different channel environments that uses instantaneous
LQI as input. We believe it will lead to more informed resource management decisions in WPANs.
Second, by sharing same unlicensed ISM bands, one WPAN device not only has to coexist with other
WPAN devices, but also other co‐channel nearby wireless technologies like WiFi. Without the knowledge
of neighbors and contention graph, they may interfere with each other, resulting in severe quality‐of service
(QoS) degradation. To achieve better coexistence in ad‐hoc WPANs where the peer‐to‐peer
topology is adopted, we propose efficient solutions to joint neighbor discovery and contention graph
inference. Specifically, two inference approaches are presented analytically, a binary inference model
and a location based inference model.

Lastly, the newly developed WPAN applications demand high data rate and stringent requirements on
service disruption, which poses more challenges on designing reliable and robust WPANs. In this
dissertation, we consider IEEE 802.15.3c WPANs and propose a robust relay placement and routing
selection solution for better resource provisioning. Specifically, two robust problems are formulated,
robust minimum relay placement (RMRP) and robust maximum utility relay placement (RMURP). We
first consider an interference‐free model, and then extend the work by incorporating a classic
directional antenna model and characterizing the link contention. Efficient algorithms are developed to
solve both problems and have been shown to incur less service disruption in presence of moving
subjects that may block the LOS paths in the environment.
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