Performance study on a DS/FH hybrid system with concatenated coding in strong partial band noise

With the wide use of wireless cellular systems, satellite communication systems, WLAN, Blue Tooth and etc., the S band has become very crowded and polluted with partial band noise. In order to construct a reliable communication system in such a polluted environment, a DS/FH hybrid system with concatenated coding scheme ((3,1,9) convolutional code + interleaver + (255,223) RS code) is studied. We investigated the relationship between data rate, frequency hopping rate and coding scheme, and the effects of different types of interleavers in the presence of AWGN and partial band noise. We have found that at a given data rate the hopping rate is the most important factor, and needs to be high enough in order for the coding scheme to show good error correcting capability because the high-rate hopping can break the long error bursts into multiple very short error bits separated by good bits (which are easy to be corrected by the Viterbi decoder). If the hopping rate is high enough, the bit error rate can still be reduced to less than 10^-5 even when the strong partial band noise interferes up to 20% of the whole band, and that symbol-based block interleaver is the best choice among the investigated 4 types of interleavers.