Punctured hopping CDMA techniques: Fundamentals and application to UWB communications

Ultra-wideband (UWB) systems have been envisaged as optimal candidates to provide high data rate communications within short range. In this paper, a novel cross-layer approach suitable for TH-UWB systems is proposed, named punctured hopping (PH). PH scheme permits to limit the throughput reduction of the basic full rate turbo coding scheme, while maintaining the same code free distance. The proposed coding scheme performs parity bits puncturing. However, different from the rate compatible punctured turbo codes (RCPTC) scheme, it works on the idea that the less significant bits in a coded frame are not completely discarded as only half of their impulses are punctured. Thus preserving the error correcting capabilities jointly with a better spectral efficiency. The performance of the proposed PH coding scheme has been examined using theoretical analysis in additive white Gaussian noise channel and simulations in a realistic multipath fading channel. It has been compared with the uncoded, the basic full rate, and the RCPTC systems in order to underline its effectiveness. The results show a significant performance gain in comparison with the RCPTC and, hence, a significant reduction of the performance loss in comparison with the basic full rate turbo coding scheme, while maintaining the same throughput of the RCPTC.