On optimum time-hopping patterns

Time-hopping patterns can be constructed from simple difference sets. By studying such constructions, it has been proven that whenever n-2, n-1, or n+1 is a prime power, then time-hopping patterns that have n terms can be constructed and are of length less than n/sup 2/. By computation it is shown that such patterns can have length less than n/sup 2/-n/sup 1.44/ for all n>