Detection of Signals in MC–CDMA Using a Novel Iterative Block Decision Feedback Equalizer

Kalapraveen Bagadi , Cv Ravikumar , K. Sathish , Mohammad Alibakhshikenari (1) , Bal Virdee , Lida Kouhalvandi , Karen Olan-Nunez , Giovanni Pau (2, 3) , Chan Hwang See , Iyad Dayoub (4, 5) , Patrizia Livreri , Sonia Aissa , Francisco Falcone , Ernesto Limiti

1 UC3M - Universidad Carlos III de Madrid [Madrid]
2 UNIBO - Alma Mater Studiorum Università di Bologna = University of Bologna
3 UC - University of California
4 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
5 COMNUM - IEMN - COMmunications NUMériques - IEMN

This paper presents a technique to mitigate multiple access interference (MAI) in multicarrier code division multiple access (MC-CDMA) wireless communications systems. Although under normal circumstances the MC-CDMA system can achieve high spectral efficiency and resistance towards inter symbol interference (ISI) however when exposed to substantial nonlinear distortion the issue of MAI manifests. Such distortion results when the power amplifiers are driven into saturation or when the transmit signal experiences extreme adverse channel conditions. The proposed technique uses a modified iterative block decision feedback equalizer (IB-DFE) that uses a minimal mean square error (MMSE) receiver in the feed-forward path to nullify the residual interference from the IB-DFE receiver. The received signal is re-filtered in an iterative process to significantly improve the MC-CDMA system’s performance. The effectiveness of the proposed modified IB-DFE technique in MC-CDMA systems has been analysed under various harsh nonlinear conditions, and the results of this analysis presented here confirm the effectiveness of the proposed technique to outperform conventional methodologies in terms of the bit error rate (BER) and lesser computational complexity.

Mots clés: CDMA; OFDM; MAI; MMSE; IB-DFE; Maximum Likelihood (ML)

Domaines: Physique [physics]; Sciences de l'ingénieur [physics]

Kalapraveen Bagadi, Cv Ravikumar, K. Sathish, Mohammad Alibakhshikenari, Bal Virdee, et al.. Detection of Signals in MC–CDMA Using a Novel Iterative Block Decision Feedback Equalizer. IEEE Access, 2022, 10, pp.105674-105684. ⟨10.1109/ACCESS.2022.3211392⟩. ⟨hal-03799710⟩