DS-CDMA downlink systems with fading channel employing the generalized receiver
Digital Signal Processing
An Upper Bound for the Extended Kloosterman Sums over Galois Rings
Finite Fields and Their Applications
A family of quadriphase sequences of period 4(2 n - 1) with low correlation and large linear span
Designs, Codes and Cryptography
| Hi-index | 754.84 |
Two families of four-phase sequences are constructed using irreducible polynomials over Z4. Family A has period L =2r-1. size L+2. and maximum nontrivial correlation magnitude Cmax⩽1+√(L+1), where r is a positive integer. Family B has period L=2(2r-1). size (L+2)/4. and Cmax for complex-valued sequences. Of particular interest, family A has the same size and period as the family of binary Gold sequences. but its maximum nontrivial correlation is smaller by a factor of √2. Since the Gold family for r odd is optimal with respect to the Welch bound restricted to binary sequences, family A is thus superior to the best possible binary design of the same family size. Unlike the Gold design, families A and B are asymptotically optimal whether r is odd or even. Both families are suitable for achieving code-division multiple-access and are easily, implemented using shift registers. The exact distribution of correlation values is given for both families