In this thesis, the bit error rate (BER) performance of a relay network using binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) modulation was compared under broadband jamming with a normalized maximum ratio combining (MRC) scheme at various jamming locations. Results show that, among various jamming locations in the relay network, jamming at the destination has more negative effects on BER than jamming at the relay. Other observations show that increasing the jamming power will cause loss in the diversity order of the relay network.