Near-capacity turbo trellis coded modulation design based on EXIT charts and union bounds - [transactions papers]

TLDR

The study aims to design capacity‑approaching IQ‑TTCM schemes for 8 PSK, 16 QAM, 32 QAM, and 64 QAM by selecting optimal component codes using symbol‑based union bound and non‑binary EXIT charts. The authors derived a symbol‑based union bound, employed I/Q interleavers to enhance diversity, and used symbol‑based EXIT charts to analyze decoding convergence, selecting component codes that approach capacity for the specified modulation schemes. Bandwidth‑efficient parallel‑concatenated Turbo Trellis Coded Modulation schemes were designed for communication over uncorrelated Rayleigh fading channels.

Abstract

Bandwidth efficient parallel-concatenated Turbo Trellis Coded Modulation (TTCM) schemes were designed for communicating over uncorrelated Rayleigh fading channels. A symbol-based union bound was derived for analysing the error floor of the proposed TTCM schemes. A pair of In-phase (I) and Quadrature-phase (Q) interleavers were employed for interleaving the I and Q components of the TTCM coded symbols, in order to attain an increased diversity gain. The decoding convergence of the IQ-TTCM schemes was analysed using symbol-based EXtrinsic Information Transfer (EXIT) charts. The best TTCM component codes were selected with the aid of both the symbolbased union bound and non-binary EXIT charts, for designing capacity-approaching IQ-TTCM schemes in the context of 8 PSK, 16 QAM, 32 QAM and 64 QAM modulation schemes.