Papers by Takis Mathiopoulos
IEEE Communications Letters, 2015
A comparative performance study, in terms of Bit Interleaved Coded Modulation Capacity (BICMC) an... more A comparative performance study, in terms of Bit Interleaved Coded Modulation Capacity (BICMC) and Total Degradation (TD), between Amplitude Phase Shift Keying (APSK) signal variants for the 2nd generation Digital Video Broadcasting via Satellite (DVB-S2) system is presented. Motivated by the observation that the presence of more signal points in the outer ring of 16-APSK signals appears to improve the performance in a non-linear (NL) channel, we investigate the performance of 2-14 and 3-13 APSK signals with two novel bit-to-symbol mappings as alternatives to the 4-12 APSK, which is currently proposed as the modulation scheme for the DVB-S2 standard.
Journal of Electronics (China), 2005
Journal of Electronics (China), 2006
This paper proposes an improved Direction Of Arrival(DOA) estimation algorithm for asynchronous m... more This paper proposes an improved Direction Of Arrival(DOA) estimation algorithm for asynchronous multipath Code Division Multiple Access(CDMA) system. The algorithm is based on the correlation matrices of outputs of decorrelator, which is a Multi-User Detection(MUD) approach, one of the key techniques for CDMA system. Through decorrelating processing, the desired user's mulipath signals can be resolved and all the other resolved multipath signal interference is eliminated. So the proposed algorithm is expected to perform much better than algorithm such as that based directly on the Matched Filter(MF) bank outputs. Simulation results confirm this. While the improved algorithm performs better and better as Signal-to-Noise Ratio(SNR) increases, the performance of algorithm based directly on the MF bank outputs can not be improved.
The use of optical spatial modulation (OSM) is
proposed as a simple, low-complexity means of achi... more The use of optical spatial modulation (OSM) is
proposed as a simple, low-complexity means of achieving spatial
diversity in coherent free space optical (FSO) communication
systems. In doing so, this paper presents a generic analytical
framework for obtaining the Average Bit Error Probability
(ABEP) of uncoded and coded OSM with coherent detection
in the presence of turbulence-induced fading. Although the
framework is general enough to accommodate any type of
channel models based on turbulence scattering, the focus of
the analysis is on the H-K distribution as such model is very
general and valid over a wide range of atmospheric propagation
conditions. Using this framework, it is shown that OSM can
offer comparable performance with conventional coherent FSO
schemes employing spatial diversity at the transmitter or the
receiver only, while outperforming the latter in terms of spectral efficiency and hardware complexity. Furthermore, various
numerical performance evaluation results are also presented
and compared with equivalent results obtained by Monte Carlo
simulations which verify the accuracy of the derived analytical
expressions.
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Papers by Takis Mathiopoulos
proposed as a simple, low-complexity means of achieving spatial
diversity in coherent free space optical (FSO) communication
systems. In doing so, this paper presents a generic analytical
framework for obtaining the Average Bit Error Probability
(ABEP) of uncoded and coded OSM with coherent detection
in the presence of turbulence-induced fading. Although the
framework is general enough to accommodate any type of
channel models based on turbulence scattering, the focus of
the analysis is on the H-K distribution as such model is very
general and valid over a wide range of atmospheric propagation
conditions. Using this framework, it is shown that OSM can
offer comparable performance with conventional coherent FSO
schemes employing spatial diversity at the transmitter or the
receiver only, while outperforming the latter in terms of spectral efficiency and hardware complexity. Furthermore, various
numerical performance evaluation results are also presented
and compared with equivalent results obtained by Monte Carlo
simulations which verify the accuracy of the derived analytical
expressions.
proposed as a simple, low-complexity means of achieving spatial
diversity in coherent free space optical (FSO) communication
systems. In doing so, this paper presents a generic analytical
framework for obtaining the Average Bit Error Probability
(ABEP) of uncoded and coded OSM with coherent detection
in the presence of turbulence-induced fading. Although the
framework is general enough to accommodate any type of
channel models based on turbulence scattering, the focus of
the analysis is on the H-K distribution as such model is very
general and valid over a wide range of atmospheric propagation
conditions. Using this framework, it is shown that OSM can
offer comparable performance with conventional coherent FSO
schemes employing spatial diversity at the transmitter or the
receiver only, while outperforming the latter in terms of spectral efficiency and hardware complexity. Furthermore, various
numerical performance evaluation results are also presented
and compared with equivalent results obtained by Monte Carlo
simulations which verify the accuracy of the derived analytical
expressions.