Radial Basis Function Aided Turbo Equalisation of TCM, TTCM, BICM and BICM-ID Assisted Wireless Transceivers

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Description/Abstract

Following a brief portrayal of the state-of-the-art a range of Coded Modulation (CM) assisted Radial Basis Function (RBF) based Turbo Equalisation (TEQ) schemes are investigated when communicating over dispersive Rayleigh fading channels. Furthermore, a reduced complexity RBF TEQ is proposed, which is referred to as an In-phase/Quadrature-phase RBF Turbo Equaliser (I/Q-RBF-TEQ). It is demonstrated that the I/Q-RBF-TEQ is capable of reducing the associated implementational complexity by equalising the I and Q components of a complex-valued phasor constellation separately. It is demonstrated that the detrimental effects of this seemingly flawed simplification may be eliminated with the aid of the proposed low-complexity turbo equaliser. The I/Q-RBF-TEQ employs iterative channel estimation and it is capable of attaining the same performance, as the significantly more complex conventional turbo equaliser. The attainable coding gain of the various CM schemes increased substantially, when employing the proposed RBF-TEQ or RBF-I/Q-TEQ, rather than the conventional non-iterative Decision Feedback Equaliser (DFE). The best overall performer was the RBF-I/Q-TEQ-TTCM scheme, requiring only 1.88~dB higher SNR at a BER of 10$^{-5}$, than the identical throughput 3~BPS uncoded 8PSK scheme communicating over an AWGN channel. The coding gain of the scheme was 16.78~dB.