Integer Sets with Distinct Sums and Differences and Carrier Frequency Assignments for Nonlinear Repeaters

The problem of assigning
n
carrier frequencies so as to avoid certain types (third and fifth order) of intermodulation interference is discussed. For the third-order case, close upper and lower bounds on the optimal solution are established; and close to optimal solutions are given for
n < 100
(previously, suboptimal solutions were known only for
n \leq 23
). For the fifth-order case, it is shown that some existing results can be applied to this problem, and suboptimal solutions obtained by this construction are given for
n \leq 17
(no solutions were known previously).