366,008 research outputs found
Amplification by stochastic interference
A new method is introduced to obtain a strong signal by the interference of
weak signals in noisy channels. The method is based on the interference of 1/f
noise from parallel channels. One realization of stochastic interference is the
auditory nervous system. Stochastic interference may have broad potential
applications in the information transmission by parallel noisy channels
Opportunistic Interference Alignment in MIMO Interference Channels
We present two interference alignment techniques such that an opportunistic
point-to-point multiple input multiple output (MIMO) link can reuse, without
generating any additional interference, the same frequency band of a similar
pre-existing primary link. In this scenario, we exploit the fact that under
power constraints, although each radio maximizes independently its rate by
water-filling on their channel transfer matrix singular values, frequently, not
all of them are used. Therefore, by aligning the interference of the
opportunistic radio it is possible to transmit at a significant rate while
insuring zero-interference on the pre-existing link. We propose a linear
pre-coder for a perfect interference alignment and a power allocation scheme
which maximizes the individual data rate of the secondary link. Our numerical
results show that significant data rates are achieved even for a reduced number
of antennas.Comment: To appear in proc. IEEE PIMRC 2008 - Workshop in Emerging Network
Perspectives in Multiuser and Cooperative MIMO (NWMIMO). 5 pages and 4
figure
Channels with block interference
A new class of channel models with memory is presented in order to study various kinds of interference phenomena. It is shown, among other things, that when all other parameters are held fixed, channel capacity C is an increasing function of the memory length, while the cutoff rate R0 generally is a decreasing function. Calculations with various explicit coding schemes indicate that C is better than R0 as a performance measure for these channel models. As a partial resolution of this C versus R0 paradox, the conjecture is offered that R0 is more properly a measure of coding delay rather than of coding complexity
Interference of Quantum Channels
We show how interferometry can be used to characterise certain aspects of
general quantum processes, in particular, the coherence of completely positive
maps. We derive a measure of coherent fidelity, maximum interference visibility
and the closest unitary operator to a given physical process under this
measure.Comment: 4 pages, 5 figures, REVTeX 4, typographical corrections and added
acknowledgemen
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