Dan Zhang

Bandwidth Exchange

Bandwidth Exchange (BE) represents a broad class of incentive mechanisms that rely on bartering for network cooperation - a user delegates a portion of its communication resources, such as bandwidth, connectivity or content, to compensate the cooperating users to whom some sort of costs is usually incurred. The bartering approach stands in contrast with traditional incentive mechanisms that make unwarranted assumptions on network operations or user perception. We take an approximate Nash bargaining solution (NBS) approach to this problem. The distributed version of this algorithm achieves at least 3dB power saving compared to noncooperation.


Modeling Random Network Coding with Differential Equations/Differential Inclusions

Recently I built a system of differential equations/differential inclusions to describe transmissions with random network coding, random coupon (a variant of random network coding) or the hybrid of both, in a wireless or wired network, with independent or correlated receptions. This approach allows to study the seemingly complicated coding process from the point of view of dynamical systems, which makes research comfortable and fruitful. For example, theorems given in [Yeung00] and [Lun07] can be recovered with this approach, as well as new results. Besides the theoretical value, it also serves as a powerful numerical tool. The approach is so natural that the usual obstacles like cycles in the network topology do not even arise and one is invited to analyze, design, optimize, categorize the coded networks with this handy tool.


Sensing the Wireless Microphone Signal from Noise and Interference

Sensing wireless microphone (WM) in the background of strong adjacent channel interference plus noise is challenging, because often the WM signal needs to be picked up at -28dB SINR. An approach that combines prewhitening and ESPRIT (Estimation of Signal Parameters Via Rotational Invariance Techniques) successfully accomplishes this task.