158 research outputs found
Symbol Error Rates of Maximum-Likelihood Detector: Convex/Concave Behavior and Applications
Convexity/concavity properties of symbol error rates (SER) of the maximum
likelihood detector operating in the AWGN channel (non-fading and fading) are
studied. Generic conditions are identified under which the SER is a
convex/concave function of the SNR. Universal bounds for the SER 1st and 2nd
derivatives are obtained, which hold for arbitrary constellations and are tight
for some of them. Applications of the results are discussed, which include
optimum power allocation in spatial multiplexing systems, optimum power/time
sharing to decrease or increase (jamming problem) error rate, and implication
for fading channels.Comment: To appear in 2007 IEEE International Symposium on Information Theory
(ISIT 2007), Nice, June 200
Multi-User Multi-Carrier Differential Chaos Shift Keying Communication System
In this paper, a multi user Multi-Carrier Differential Chaos Shift Keying
(MC-DCSK) modulation is presented. The system endeavors to provide a good
trade-off between robustness, energy efficiency and high data rate, while still
being simple. In this architecture of MC-DCSK system, for each user, chaotic
reference sequence is transmitted over a predefined subcarrier frequency.
Multiple modulated data streams are transmitted over the remaining subcarriers
allocated for each user. This transmitter structure saves energy and increases
the spectral efficiency of the conventional DCSK system.Comment: Accepted in the IEEE International Wireless Communications and Mobile
Computing Conference (IWCMC 2013
Performance of Optimum Combining in a Poisson Field of Interferers and Rayleigh Fading Channels
This paper studies the performance of antenna array processing in distributed
multiple access networks without power control. The interference is represented
as a Poisson point process. Desired and interfering signals are subject to both
path-loss fading (with an exponent greater than 2) and to independent Rayleigh
fading. Using these assumptions, we derive the exact closed form expression for
the cumulative distribution function of the output
signal-to-interference-plus-noise ratio when optimum combining is applied. This
results in a pertinent measure of the network performance in terms of the
outage probability, which in turn provides insights into the network capacity
gain that could be achieved with antenna array processing. We present and
discuss examples of applications, as well as some numerical results.Comment: Submitted to IEEE Trans. on Wireless Communication (Jan. 2009
Bit Error Rate is Convex at High SNR
Motivated by a wide-spread use of convex optimization techniques, convexity
properties of bit error rate of the maximum likelihood detector operating in
the AWGN channel are studied for arbitrary constellations and bit mappings,
which may also include coding under maximum-likelihood decoding. Under this
generic setting, the pairwise probability of error and bit error rate are shown
to be convex functions of the SNR in the high SNR regime with
explicitly-determined boundary. The bit error rate is also shown to be a convex
function of the noise power in the low noise/high SNR regime.Comment: to be presented at IZS-10, March 201
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