Leveraging Infrastructure to Enhance Wireless Networks

Wireless networks have become an increasingly important part of our daily lives. The rise in number of mobile clients and the subsequent services being offered on them has led to not just an increase in demand for wireless data but also change in network traffic characteristics. The proliferation of mobile devices also causes change in wireless topologies over time. However, the available bandwidth remains scarce. Thus, the need for wireless networks to be more spectral efficient is critical. This dissertation investigates a suite of solutions to address this trend in changing wireless networks. We first investigate physical layer solutions at the node level to enhance wireless networks and then look at collaborative techniques across distributed nodes to improve wireless networks. First, collaborative communication techniques such as interference alignment, distributed MIMO have been theoretically explored to enhance the spectral efficiency of wireless networks. However, implementing such solutions in practice require tight synchronization requirements either in time, frequency or both. We present Vidyut, which uses the power lines to provide time and frequency synchronization across distributed nodes to implement such techniques in practice. The advantage of using an orthogonal medium (the power lines) for synchronization purposes alleviates the MAC overhead required to simply synchonize nodes distributed in space. We demonstrate