On the selection of optimum diversity and code rate for FFH/8FSK under partial band interference for multimedia data transmission

The built-in diversity of the fast frequency hopped spread spectrum communication system can provide inherent protection against interference for the multimedia data transmission for tactical use. Additionally, FEC coding can greatly enhance the system performance. However, care must be taken toward optimum performance in a power limited system. In this paper, effect of diversity L is observed with/without convolutional coding for the performance of the FFH/8FSK modem under additive white Gaussian noise (AWGN) and partial band noise interference using different nonlinear diversity combiners. Simulation results show that proper combination of diversity/nonlinear combiners, M-ary modulation and FEC coding is very effective. However, for the modems using coding, use of high diversity L does not necessarily improve the BER performance, thus resulting in an optimum value of diversity for each particular modem under consideration.