On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We study communication over atmospheric turbulence channels based on LDPC-coded, multidimensional OAM signal constellations. Multidimensional signal constellation is obtained as the Cartesian product of one-dimensional signal constellation X={(i-1)d, i=1, 2, ⋯, M} (where d is the Euclidean distance between neighboring signal constellation points and M is the number of amplitude levels) as XN={(x1, x2, ⋯, xN)|xi is from X, for every i}. This scheme represents an energy efficient alternative, since log2(M N) bits/symbol can be transmitted. We describe two possible implementations of N-dimensional OAM modulator and demodulator: (1) volume holograms based, and (2) multimode fibers (MMFs) based. We evaluate the performance of this scheme by determining conditional symbol probability density functions (PDFs) from numerical propagation data. Two cases of practical interest are studied: (i) when conditional PDFs are known on the receiver side, and (ii) when conditional PDFs are not known and Gaussian approximation is used instead. We show that in case (ii) an early error floor occurs because of inaccurate PDF assumption, which is caused by OAM crosstalk introduced by the atmospheric turbulence. We also show that the OAM modulation is more sensitive to atmospheric turbulence as the number of dimensions increases. Finally, we evaluate the BER performance for different amplitude levels and different number of OAM dimensions.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume8162
DOIs
StatePublished - 2011
EventFree-Space and Atmospheric Laser Communications XI - San Diego, CA, United States
Duration: Aug 24 2011Aug 25 2011

Other

OtherFree-Space and Atmospheric Laser Communications XI
CountryUnited States
CitySan Diego, CA
Period8/24/118/25/11

Fingerprint

Atmospheric turbulence
Atmospheric Turbulence
atmospheric turbulence
probability density functions
Probability density function
constellations
Modulation
communication
modulation
Conditional Density
Communication
Conditional probability
Constellation-X
demodulators
Multimode Fiber
Gaussian Approximation
Multimode fibers
Demodulators
Evaluate
Crosstalk

Keywords

  • Atmospheric turbulence
  • Coded modulation
  • Forward error correction
  • Free-space optical (FSO) communication
  • Low-density parity-check (LDPC) codes
  • Modulation
  • Multiplexing
  • Orbital angular momentum (OAM)

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Djordjevic, I. B., Anguita, J., & Vasic, B. V. (2011). On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 8162). [81620G] https://doi.org/10.1117/12.894263

On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels. / Djordjevic, Ivan B; Anguita, Jaime; Vasic, Bane V.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8162 2011. 81620G.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Djordjevic, IB, Anguita, J & Vasic, BV 2011, On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 8162, 81620G, Free-Space and Atmospheric Laser Communications XI, San Diego, CA, United States, 8/24/11. https://doi.org/10.1117/12.894263
Djordjevic IB, Anguita J, Vasic BV. On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8162. 2011. 81620G https://doi.org/10.1117/12.894263
Djordjevic, Ivan B ; Anguita, Jaime ; Vasic, Bane V. / On the LDPC-coded OAM modulation for communication over atmospheric turbulence channels. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8162 2011.
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