Quaternary constant-amplitude codes for multicode CDMA
IEEE Transactions on Information Theory
Improved bounds on weil sums over galois rings and homogeneous weights
WCC'05 Proceedings of the 2005 international conference on Coding and Cryptography
Improved p-ary codes and sequence families from Galois rings
SETA'04 Proceedings of the Third international conference on Sequences and Their Applications
Finite Fields and Their Applications
| Hi-index | 754.90 |
An upper hound for Weil-type exponential sums over Galois rings was derived by Kumar, Helleseth, and Calderbank (see ibid., vol.41, no.3, p.456, 1995). This bound leads directly to an estimate for the minimum distance of Z4-linear trace codes. An improved minimum-distance estimate is presented. First, McEliece's result on the divisibility of the weights of binary cyclic codes is extended to Z4 trace codes. The divisibility result is then combined with the techniques of Serre (1983) and of Moreno and Moreno (see ibid., vol.40, no.11, p.1101, 1994) to derive the improved minimum-distance estimate. The improved estimate is tight for the Kerdock code as well as for the Delsarte-Goethals codes