Today's wireless systems are in the midst of a transformation driven by the revolution in wireless network availability and mobile data traffic growth over the past decade. As the wireless medium has become the primary source of communication and Internet connectivity, and as devices and wireless technologies become more sophisticated and capable, there has been a surge in the capacity demands of applications that run over these wireless devices. To sustain the volume and QoS guarantees of the data generated, the opportunity and need to exploit complex wireless systems and technologies has firmly emerged as a solution to enable the timely and reliable delivery of data, while handling the inherent challenges of a crowded wireless medium, such as congestion, interference, and hidden terminals.
In this dissertation, we build efficient solutions and protocols with a theoretical foundation to address the challenges that arise in complex wireless systems. Our research particularly focuses on the opportunities and challenges of sophisticated technology and systems in emerging wireless networks. We target the main thrusts in the evolution of wireless networks that create significant opportunity to exploit higher theoretical capacity, and have direct implications on our day-to-day wireless interactions. Our work advances the field of wireless and mobile communication by building practical, deployable, and resource-aware wireless systems that exploit higher bandwidths and configure wireless parameters to accommodate traffic demands by leveraging and advancing diverse research areas such as theory, analysis, protocol design, and wireless networking. Specifically, we identify the erroneous assumptions and fundamental limitations of existing solutions in capturing the true and complex interactions between wireless devices and protocols. We use these insights to guide practical and efficient protocol design, followed by thorough analysis and evaluation in testbed implementations via prototypes and measurements.
Our work integrates two complementary approaches to enable and meet the ever-growing demand for wireless network resources. Specifically, the first approach designs low-layer systems and protocols that leverage emerging wireless systems and sophisticated technologies to exploit and provide higher bandwidth capacity. The second approach designs upper-layer systems or platforms that enable application operability in mobile environments. Our system designs cover various technologies from White Space Spectrum, to MIMO and MU-MIMO smart-antenna technology in IEEE 802.11 WLANs as well as application development on mobile devices.