Spectrum efficiency of a frequency-hopped MFSK spread spectrum mobile radio system

The spectrum efficiency of a frequency-hopped multilevel frequency-shift keying (FH-MFSK) spread spectrum modulation technique proposed for use in mobile radio systems is evaluated. The analysis assumes randomly chosen address vectors, a perfect synchronization at the receiver, and noncoherent detection. With perfect transmission where the only degradation is due to mutual interference, the efficiency is 0.262, 0.295, and 0.345 at an average bit error rate of 10^-3for 1.64, 3.41, and 20 MHz bandwidth. However, with transmission impairments consisting of additive white Gaussian noise and frequency selective Rayleigh fading, which characterize the mobile radio channel, the efficiency depends on the average signal-to-noise ratio (SNR), and on the average bit error rate.