Performance of a convolutionally coded hard decision DS receiver in pulsed CW interference

The performance of a hard decision DS/BPSK receiver in an additive white Gaussian noise channel with interference from a pulsed continuous wave (CW) jammer was analyzed with Monte-Carlo simulations. Exact bit error rates are derived for the uncoded BPSK and direct-sequence (DS)/BPSK systems with interference from a pulsed CW jammer. An optimum convolutional code of constraint length 7 and a code rate of 1/2 was used with a hard decision Viterbi decoder. A 63 chip m-sequence was used as a spreading code and one bit was spread by a code sequence. The simulation results show that the bit error rates of the uncoded systems are equivalent to the theoretical bit error rates derived. The simulated DS systems can survive about 36 dB greater jamming than the BPSK system. The channel coding was found to remove the effect of a pulsed CW jammer totally when the pulse duty factor ⩽0.01