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We focus on an opportunistic communication system consisting of multiple independent channels with time-varying states. With limited sensing, a user can only sense and access a subset of channels and accrue rewards determined by the state of the sensed channels. We formulate the problem of optimal sequential channel probing as a restless multi-armed bandit process, for which a powerful index policy-Whittle's...
A variable fractional delay (VFD) filter is presented that constitutes an efficient alternative to the usual Farrow structure. The filter is constructed by multiplying the signal to interpolate by a window with proper truncation properties, and then applying the sampling theorem. The resulting interpolator involves less arithmetic operations than the existing variants of the Farrow structure. Besides,...
Some communication applications, like multimedia, deliver data of different importance classes allowing unequal error protection (UEP) levels. In this paper, a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM) is considered with a new UEP bit-loading algorithm based on the non-UEP algorithm by Chow, Cioffi, and Bingham. In the proposed bit-loading...
We designed and built a novel all-optical re-timing, re-amplifying, and re-shaping (3R) regeneration system based on terahertz optical asymmetric demultiplexers (TOADs) developed in our laboratory. The system is capable of parallel processing multiple wavelengths, a feature which will significantly improve the scalability of current wavelength division multiplexing (WDM) networks. Performance against...
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