Near-Capacity UWB Impulse Radio Using EXIT Chart Aided Self-Concatenated Codes

A near-capacity time hopping (TH) pulse position modulation (PPM) based ultrawideband (UWB) impulse radio (IR) system is proposed, which invokes iteratively detected self-concatenated convolutional codes (SeCCC) and employs powerful design technique of extrinsic information transfer (EXIT) charts. Orthogonal prolate spheroidal wave function (OPSWF) based signalling pulse shapes are used for the sake of minimizing the multi-user interference (MUI) and intersymbol interference (ISI). Recursive systematic convolutional (RSC) codes are employed as constituent codes combined with an interleaver for randomising the extrinsic information exchange between the constituent codes. Furthermore, a puncturer assists us in increasing the achievable bandwidth efficiency. Iterative decoding is invoked for exchanging extrinsic information between the hypothetical decoder components at the receiver end. The convergence behaviour of the decoder is analysed with the aid of bit-based EXIT charts. Finally, we propose a novel THPPM-UWB-IR-SeCCC system configuration, which is capable of operating within about 0.9 dB of the information-theoretic limits.