31,744 research outputs found
On a matrix inequality related to the distillability problem
We investigate the distillability problem in quantum information in
\bbC^d\ox\bbC^d. A special case of the problem has been reduced to proving a
matrix inequality when . We investigate the inequality for two families of
non-normal matrices. We prove the inequality for the first family with
and two special cases of the second family with . We also prove the
inequality for all normal matrices with .Comment: 19 pages, comments are welcom
Performance of a Multiple-Access DCSK-CC System over Nakagami- Fading Channels
In this paper, we propose a novel cooperative scheme to enhance the
performance of multiple-access (MA) differential-chaos-shift-keying (DCSK)
systems. We provide the bit-error-rate (BER) performance and throughput
analyses for the new system with a decode-and-forward (DF) protocol over
Nakagami- fading channels. Our simulated results not only show that this
system significantly improves the BER performance as compared to the existing
DCSK non-cooperative (DCSK-NC) system and the multiple-input multiple-output
DCSK (MIMO-DCSK) system, but also verify the theoretical analyses. Furthermore,
we show that the throughput of this system approximately equals that of the
DCSK-NC system, both of which have prominent improvements over the MIMO-DCSK
system. We thus believe that the proposed system can be a good framework for
chaos-modulation-based wireless communications.Comment: 4 pages, 5 figures, accepted, IEEE ISCAS, 201
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