The effects of the cross-entropy stopping criterion and quadrature amplitude modulation on iterative turbo decoding performance

One of the most often-used stopping criteria is cross-entropy criterion (CESC). The CESC can stop turbo decoder iterations early by calculating mutual information improvements while maintaining bit error rate (BER) performance. Most research on iterative decoding has utilised low-modulation methods, such as binary phase-shift keying. However, a high-speed network requires high modulation to transfer data at speeds. Hence, technique needs be integrated into match its speed. Therefore, present paper investigated and analysed effects quadrature amplitude (QAM) decoding. Three thresholds were simulated tested under four situations: different code rates, QAM formats, generators, frame sizes. results revealed that in situations, use suitable only when signal-to-noise ratio (SNR) high. This because significantly reduces average iteration number (AIN) BER. terminate SNR save more than 40% AIN compared with fixed criterion. Meanwhile, low SNR, fails early, which maximum AIN.