Chip-by-Chip Turbo Coding for DS/SS Systems
نویسندگان
چکیده
Most of error correcting codes applying to DS/SS systems are such that information data is first (bit-bybit) encoded and then spread by pseudo noise (PN) sequence. Thus, coding gain achieved by such systems are mainly due to the error correcting codes and the redundancy produced by the spreading codes shows no effect on the coding gain. In this paper, a chip-by-chip Turbo coding for DS/SS systems is proposed. The input information data is first spread by PN sequence and then fed into the Turbo-encoder which operates in chip timing. As the Turbo-encoder operates in chip timing, a large interleaving size would be obtained, which improves the performance. As results, superior performances with coding gain of more than 3.0 dB and 5.0 dB for AWGN and Rayleigh-fading channel, respectively, were found with short frame size of information data. key words: Turbo-codes, chip-by-chip coding, DS/SS modulation, energy compensation
منابع مشابه
Comprehensive evaluation of chip interleaving effect on turbo-coded DS-SS in a Rayleigh fading channel with antenna diversity reception
In this paper, we present a comprehensive performance evaluation of chip interleaving effect on turbo coded direct sequence spread spectrum (DS-SS) system in a frequency non-selective Rayleigh fading channel with antenna diversity reception. At the transmitter, chip interleaver scrambles the SF (spreading factor) chips associated with a data symbol and transforms the transmission channel into a...
متن کاملChip Interleaving for DS-CDMA with Frequency Domain Equalization in a Frequency Selective Rayleigh Fading Channel
Abstract DS-CDMA with frequency domain minimum mean square error (MMSE) equalization can provide much better performance than that with rake combining in a frequency selective fading channel. Chip interleaving is a form of channel interleaving that improves the DS-CDMA performance by converting the channel into a highly time selective channel. When frequency domain equalization is used, the fre...
متن کاملPerformance of DS–CDMA with chip interleaving and frequency domain equalisation in a fading channel
Conventional time domain rake combining can be replaced by minimum mean square error frequency domain equalisation (MMSE–FDE) with much better performance in a frequencyselective fading channel, since the frequency selectivity of the channel is thoroughly exploited. Chip interleaving is a form of channel interleaving that improves the DS–CDMA performance by taking advantage of the time selectiv...
متن کاملCoding vs. Spreading for Narrow-Band Interference Suppression
The use of active narrow-band interference (NBI) suppression in direct-sequence spread-spectrum (DS-SS) communications has been extensively studied. In this paper, we address the problem of optimum coding-spreading tradeoff for NBI suppression. With maximum likelihood decoding, we first derive upper bounds on the error probability of coded systems in the presence of a special class of NBI, name...
متن کاملChip interleaved turbo codes for DS-CDMA mobile radio in fading channel
A new channel interleaving method, called chip interleaving, for direct sequence code division multiple access (DS-CDMA) is proposed. A chip interleaver scrambles the chips and transforms the transmission channel into a highly time-selective or highly memoryless channel. It was found that the turbo decoding performance which degrades in a fading channel is significantly improved with chip inter...
متن کامل