Performance considerations of frequency-hopping multiple access

The basic system parameters of a frequency-hopping multiple-access system are investigated. Noncoherent binary FSK and M-ary FSK signal formats are studied in a random-access asynchronous environment. Both slow and fast frequency hopping are considered. Under relatively ideal conditions, the degradation in performance with respect to the number of users is determined. The dependence on performance due to hopping rate and bandwidth constraint is developed. It is shown, for example, that, for fast hopping, the optimum hopping rate is that which spreads the users' power over the entire available bandwidth during each baud time. This agrees with the basic spread spectrum philosophy of making the signal appear white over as wide a bandwidth as possible. The computational results describe the trade-off between the number of tones in M-ary FSK and the number of hops per symbol. Given a specified number of tones in the frequency-hopping system, the results describe the manner in which the system degrades as the number of users is increased.