Side Information Gained From Signal Matrices in FFH Spread Spectrum Systems

Vajda, I [Vajda, István (Kriptográfia), szerző]

Angol nyelvű Tudományos Szakcikk (Folyóiratcikk)
    The fast frequency hopping spread-spectrum system investigated has signal structure, which is characterized by a frequency-time matrix of size Q x L. The Q-ary source symbols are encoded into such binary signal matrices. This matrices are transmitted using on-off FSK modulation, i.e. sending a short sine wave packet in frequency-time cells (chips) corresponding to the one valued elements of the matrix. At the receiving end the elements of the matrix are hard (0-1) detected, resulting in a received binary matrix. The usual symbol detection rule decides on a symbol (matrix) having maximal Hamming-correlation with the received matrix. This paper deals with the question of exploiting side information from the received binary matrix in order to measure the reliability of the reception. This reliability information can be used to improve the error rate performance of a concatenated coding scheme, where the symbol-to-matrix code is the inner code and an appropriate Q-ary block code is used for outer code. In the analysis partially jammed channels are considered, where a given percent of symbols from the words of the outer code are supposed to be corrupted by jamming. Binary asymmetric channel with crossover probabilities p(d) and p(f) is chosen as the model of the chip-channel under jamming.
    Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSL
    2020-04-07 21:54