EXIT-Chart-Aided Three-Stage Concatenated Ultrawideband Time-Hopping Spread-Spectrum Impulse Radio Design

A serially concatenated and iteratively decoded irregular variable-length coding (IrVLC) scheme is amalgamated with a unity-rate precoded time-hopping (TH) pulse-position-modulation (PPM)-aided ultrawideband (UWB) spread-spectrum (SS) impulse radio design. The proposed design is capable of operating at low SNRs in Nakagami-m fading channels contaminated by partial band noise jamming (PBNJ) as a benefit of lossless IrVLC joint source and channel coding. Although this scheme may readily be used for lossless video or audio compression, for example, we only used it here for lossless near-capacity data transmission. A number of component variable-length-coding (VLC) codebooks having different coding rates are utilized by the IrVLC scheme for encoding specific fractions of the input source symbol stream. EXtrinsic Information Transfer (EXIT) charts are used to appropriately select these fractions to shape the inverted EXIT curve of the IrVLC and, hence, to match that of the inner decoder, which allows us to achieve an infinitesimally low bit error ratio (BER) at near-capacity SNR values.