Over half the planet's population currently has access to the Internet in some form. Consequently, Internet usage has increased exponentially on mobile and fixed networks. In particular, video traffic now accounts for 80% of all Internet traffic, largely thanks to the rise of streaming platforms and video content from social media. With this tremendous growth, it becomes challenging to maintain consistent and high-quality service to all connected users. This is particularly true in the case of video sessions, which demand relatively consistent, high volume bandwidth to maintain high-quality sessions for end-users.

However, the presence of connectivity does not necessarily equate to usable service. Even in well-provisioned deployments, network resiliency can be an issue. Our own assessment of multiple networks across the US indicates that there is a wide disparity between reported coverage and actual usability. Numerous studies, including ours, indicate that LTE penetration in rural areas is far less than what is typically reported by providers and much less prevalent and lower quality than that in urban areas. Similarly, for fixed broadband, studies have observed highly variable median speeds across the globe, including South America, the Middle East, and Africa. Within the US itself, broadband speeds vary considerably as well. Finally, networks have to support multitudes of end-user devices (e.g., mobile phones, laptops, desktops) and a wide variety of application types, many with challenging and strict delivery requirements. As a result, ensuring high-quality, low-variability service quality under variable conditions is exceptionally challenging.

This dissertation is aimed at tackling this challenge. We assess how existing technologies and standards function in complex environments: lack of deterministic pathways for Internet connectivity, presence of congestion and other resource constraints, and temporal or spatial variability in network performance. Based on our extensive analysis of real-world conditions, we produce cellular and broadband systems designed to bridge the technological gap for end-users in challenging network conditions.

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 and complexity of applications that run over these wireless devices. To sustain the volume and QoE guarantees of the data generated, the opportunity and need to rethink wireless network design across all the layers of the protocol stack 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.

The research work presented in this dissertation builds efficient solutions and protocols with a theoretical foundation to address the challenges that arise in rethinking wireless network design. Example challenges include managing the overhead associated with complex systems. My work particularly focuses on the opportunities and challenges of sophisticated technology and systems in emerging wireless networks. I target the main thrusts in the evolution of wireless networks that create significant opportunity to achieve higher theoretical capacity, and have direct implications on our day-to-day wireless interactions: from enabling multifold increase in capacity in wireless physical links, to developing medium access techniques to exploit the high speed links, and making the applications more bandwidth efficient. I build deployable, and resource-aware wireless systems that exploit higher bandwidths by leveraging and advancing diverse research areas such as theory, analysis, protocol design, and wireless networking. Specifically, I identify the erroneous assumptions and fundamental limitations of existing solutions in capturing the true and complex interactions between wireless devices and protocols. I use these insights to guide practical and efficient protocol design, followed by thorough analysis and evaluation in testbed implementations via prototypes and measurements. I show that my proposed solutions achieve significant performance gains, at minimum cost to overhead.