Cognitive Radio in arXiv.org

Sometimes I wonder how research could be done before the Internet era. I can imagine how long it would take to get something published: after finished, the article had to be submitted by post to the associated editor, then to the reviewers, comments and responses back and forth, back and forth and so on. When the article is finally accepted it would take a couple of months before the research community had access to the printed journal.

While the publishing time got drastically reduced with the invention of the email and electronic documents, it can still be considered slow compared to the current pace of the research. Since this may hinder the interaction between different groups working in the same topic, some researchers choose to submit an early (non peer-reviewed) electronic version of their work to e-print repositories, such as arXiv.org.

In this repository there exists no section dedicated exclusively to signal processing articles. Nevertheless, many of them are archived under the Information Theory (cs.IT) tag. If we search arXiv.org for "cognitive radio" we can find some related papers.

Presented at CrownCom'10 last June, the paper "Binary is Good: A Binary Inference Framework for Primary User Separation in Cognitive Radio Networks" by Huy Nguyen, Rong Zheng and Zhu Han poses the problem of distinguishing and characterizing primary users when we have a large number of collaborating secondary users. The observations by secondary users are modeled as boolean OR mixtures of underlying binary vectors. I had not seen before this approach, kind of "binary processing".

In the paper "Spectrum Sensing in Cooperative Cognitive Radio Networks with Partial CSI" Chong Han, Ido Nevat, and Jinhong Yuan develop an algorithm for cooperative spectrum sensing in a relay based cognitive radio network. To this end they use a bayesian expectation maximisation to approximate the solution of the non-convex problem resulting from a simplification of the likelihood. Beats the energy detector. From almost the same authors is the paper "Blind Spectrum Sensing in Cognitive Radio over Fading Channels and Frequency Offsets", which studies the effect of frequency offsets due to oscillator mismatch and Doppler effect. A novel approach to approximate the Likelihood Ratio Test (LRT) using a single point estimate using a low complexity Adaptive Notch Filter (ANF).

Other papers present the key word compressive in their title, such as "Compressive Wideband Spectrum Sensing for Fixed Frequency Spectrum Allocation" and "Robust Compressive Wideband Spectrum Sensing with Sampling Distortion" by Yipeng Liu and Qun Wan. These papers attempt to use compressive sensing techniques to wideband spectrum reconstruction.

However, I want to finish this post with two of Yonina Eldar's papers about the modulated converter entitled "Xampling", which made me discover arXiv.

P.S. Congratulations Spain!