Constant-energy code 

Root code for the Spherical Kingdom

Description

Code whose codewords are points on a real or complex sphere whose radius squared is called the energy. Typically, only angular distances between points are relevant for code performance, so one can normalize codewords of a constant-energy code to obtain up a spherical code, i.e., a constant energy code with energy one.

Protection

Constant-energy codes are sphere packings constrained to lie on a sphere, meaning that they can be used to transmit information through the AGWN channel. For a given dimension \(n\), number of codewords \(M\), and average energy \(P\), the constant-energy Gaussian channel coding problem asks to find a set of \(M\) codewords of energy \(nP\) that minimizes the error probability during transmission; see [1; Ch. 3].

Notes

See [2; Ch. 7] for more details.

Parent

  • Bounded-energy code — Constant-energy codes are bounded-energy codes constrained to lie on a sphere.

Child

Cousin

  • Quantum spherical code (QSC) — QSCs are quantum analogues of spherical and constant-energy codes because they store information in quantum superpositions of points on a sphere in quantum phase space.

References

[1]
J. H. Conway and N. J. A. Sloane, Sphere Packings, Lattices and Groups (Springer New York, 1999) DOI
[2]
T. Ericson, and V. Zinoviev, eds. Codes on Euclidean spheres. Elsevier, 2001.
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Zoo Code ID: points_into_spheres

Cite as:
“Constant-energy code”, The Error Correction Zoo (V. V. Albert & P. Faist, eds.), 2022. https://errorcorrectionzoo.org/c/points_into_spheres
BibTeX:
@incollection{eczoo_points_into_spheres, title={Constant-energy code}, booktitle={The Error Correction Zoo}, year={2022}, editor={Albert, Victor V. and Faist, Philippe}, url={https://errorcorrectionzoo.org/c/points_into_spheres} }
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https://errorcorrectionzoo.org/c/points_into_spheres

Cite as:

“Constant-energy code”, The Error Correction Zoo (V. V. Albert & P. Faist, eds.), 2022. https://errorcorrectionzoo.org/c/points_into_spheres

Github: https://github.com/errorcorrectionzoo/eczoo_data/edit/main/codes/classical/spherical/points_into_spheres.yml.