This is an open access article published by the IET under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/)
The authors outline an approach to construct capacity-approaching balanced quadrature phase shift keyed (QPSK) codes. These codes ensure an equal number of different symbol values and many symbol transitions in the encoded sequence in order to assist practical demodulators to accurately recover symbol values. Their codes are comprised of instantaneously decodable variable-length codewords that exhibit excellent performance with average code rates higher than previously reported fixed-length balanced QPSK codes.
References
-
-
1)
-
5. Steadman, A., Fair, I.J.: ‘Variable-length constrained sequence codes’, IEEE Commun. Lett., 2013, 17, (1), pp. 139–142 (doi: 10.1109/LCOMM.2012.120312.121420).
-
2)
-
7. Fair, I.J., Jamieson, C.: ‘Tabular construction of balanced codes’, IET Elec. Lett., 2013, 49, (6), pp. 997–999 (doi: 10.1049/el.2013.1658).
-
3)
-
18. Xin, Y., Fair, I.J.: ‘A performance metric for codes with a high-order spectral null at zero frequency’, IEEE Trans. Inf. Theory, 2004, 50, (2), pp. 385–394 (doi: 10.1109/TIT.2003.822610).
-
4)
-
1. Cattermole, K.W.: ‘Principles of digital line coding’, Int. J. Electron., 1983, 55, (1), pp. 3–33 (doi: 10.1080/00207218308961573).
-
5)
-
7. Jamieson, C., Fair, I.J.: ‘Evaluation of the capacity of constrained codes with multiple constrained signalling dimensions’, IET Commun., 2014, 8, (13), pp. 2238–2245 (doi: 10.1049/iet-com.2013.0895).
-
6)
-
8. Böcherer, G., Mather, R.: ‘Matching dyadic distributions to channels’. Proc. 2011 Data Compression Conf., Snowbird UT, USA, 29–31 March 2011.
-
7)
-
4. Fair, I.J., Martin, D.: ‘Generation of balanced QPSK sequences through guided scrambling’, IET Commun., 2015, 9, (11), pp. 1404–1411 (doi: 10.1049/iet-com.2015.0009).
-
8)
-
12. Pierobon, G.: ‘Codes for zero spectral density at zero frequency’, IEEE Trans. Inf. Theory, 1984, 30, (2), pp. 435–439 (doi: 10.1109/TIT.1984.1056858).
-
9)
-
2. Immink, K.A.S.: ‘Codes for mass data storage systems’ (Shannon Foundation, 2004, 2nd edn.).
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content/journals/10.1049/joe.2015.0150
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Variable-length balanced codes for quadrature phase shift keyed systems