PhD Proposal abstract: Apurv Bhartia, GDC 6.816

Contact Name: 
Lydia Griffith
Dec 10, 2013 11:00am - 1:00pm

PhD Proposal abstract: Apurv Bhartia

Date: Dec. 10th, 2013
Time: 11 am
Place: GDC 6.816
Supervisor: Prof. Lili Qiu

Title: Towards Improving Spectrum Efficiency in Wireless Networks

With the proliferation of wireless enabled devices, the information being transmitted on the wireless spectrum has increased manifolds. This explosive growth of wireless traffic has created spectrum crisis. Further, combined with the inherently lossy wireless medium, it is imperative to develop techniques that can significantly improve wireless spectrum efficiency. This proposal develops three complementary techniques to enhance spectrum efficiency: (i) sending more information per transmission, (ii) sending more transmissions per spectrum, and (iii) selecting the right spectrum for transmission.

More specifically, in (i), we observe that network coding allows us to send more information per transmission by combining (coding) multiple packets together in a single transmission and letting multiple receivers extract different information from the same transmission. However, wireless networks are inherently prone to loss and how to harness network coding gain under such
conditions poses a significant challenge. To this end, we develop a novel routing protocol, called O3, which jointly optimizes network coding, opportunistic routing, and rate limiting.

Multi-antenna devices (MIMO) dramatically increase wireless network capacity by sending multiple transmissions simultaneously. However, most existing work focuses on MIMO in single hop wireless networks, and how to effectively extend MIMO benefits to multihop wireless networks remain an open problem. In (ii), we propose a new routing protocol, called M3, which
is the first practical distributed MIMO routing protocol. It optimizes spatial multiplexing, routing, and rate limiting in the presence of interference. Using simulation and testbed experiments, we show it out-performs state-of-the-art shortest part routing and opportunistic routing protocols.

Finally, in (iii), we examine spectrum selection at two different granularities: (a) selecting a channel to transmit a frame, and (b) selecting a sub-carrier within a channel to transmit a symbol of the frame. In (a), we propose a novel channel hopping algorithm that allows different nodes converge to a fair and efficient channel hopping sequence in a completely distributed
fashion. In (b), we develop a series of techniques to harness the frequency diversity of the channel while transmitting the current frame. We demonstrate the effectiveness of both approaches using simulation and testbed experiments.