Turbo codes for noncoherent FH-SS with partial band interference

Abstract

Abstract-In this paper, turbo codes are investigated in a slow frequency-hopped spread spectrum (FH-SS) system with partialband jamming. In addition, full-band thermal noise is present. The channel model is that of a partial-band jammer in which a fraction of the frequency band is jammed and the remaining fraction is unjammed. This paper focuses on the implemention and performance of a modified turbo decoder for this model. We refer to the knowledge that each transmitted bit is jammed as channel state information. We consider cases of known or unknown channel state and variable number of bits per hop. Our approach is to modify the calculation of branch transition probabilities inherent in the original turbo decoder. For the cases with no side information and multiple bits per hop, we iteratively calculate channel state estimates. Analytical bounds are derived and simulation is performed for noncoherent demodulation. The performance of turbo codes is compared with a Reed-Solomon and a concatenated code comprised of a convolutional inner code and Reed-Solomon outer code.

Diversity Combining and SNR Estimation for Turbo-Coded Frequency-Hopped Spread-Spectrum in Partial-Band Interference and Fading Channels

“…7 and 8 where the information bit error rate (BER) is plotted versus a range of E b /N o . It is well-known that the worst-case ρ for turbo-coded SFH is unity [3], which is an expensive strategy for hostile interference and unlikely for unintentional interference. Our later conclusions have been found to be valid for the entire range of duty factors ρ.…”

“…The Maximum-Likelihood (ML) diversity combining technique was derived for non-coherent binary frequency shift keying (NCBFSK) in [2] in the absence of background noise as a lower bound for performance, and in [1] was derived in the presence of both background noise and PBI. Furthermore, error control coding was used to mitigate the effect of PBI in [3][4][5][6]. However, no repetition diversity was used in those works and channel fading was not considered.…”

Iterative Equalization and Decoding for SFH Spread-Spectrum Communications using Reed–Solomon Codes

“…Most previous work on iterative detection techniques for SFH communications has focused instead on the performance of iterative decoding with single-path static or frequency-flat fading channels (in some instances in the presence of partial-band interference). Among the systems addressed are those using a single convolutional encoder [12], parallel concatenated convolutional codes [13][14][15], SCC codes [16,17], turbo product codes [18,19], and bit-interleaved coded modulation [20,21]. A form of packet-level iterative detection is considered in [22] for a SFH packet radio system using R-S coding in partial-band interference, where feedback from successful bounded-distance decoding of R-S code words is used to make per-dwell erasures for the remaining un-decoded code words in the packet.…”

Image restoration for Reed-Solomon coded SFH/MFSK System With Partial-Band Noise jamming

“…Kang [4] demonstrated the superior performance of turbo codes over convolutional codes in FH-SS system. Later on, Kang [5] investigated turbo codes in noncoherent SFH-SS with partialband interference and analyzed the performance by comparing with variable number of bits per hop and either with or without channel state information. Besides, the concatenation of RS code with other codes has also been proposed for SFH systems [6] [7].…”