Partial-band jamming rejection of FFH/BFSK with product combining receiver over a Rayleigh-fading channel

An exact closed-form expression of the characteristic function is derived for a fast frequency-hopping (FFH) binary orthogonal frequency-shift-keying (FSK) spread-spectrum (SS) communication system. The FFH system employs a product combining receiver over a Rayleigh-fading channel with partial-band jamming and additive white Gaussian noise (AWGN). The derived characteristic function is then used to obtain a compact bit error rate (BER) expression for different diversity levels. Our study shows that there exists an optimum diversity level under certain channel conditions.