The Performance Degradation of a DDEA Based Turbo Equalization System
Qing-Ping Meng, Zhou Xin-li · International Conference on Electric Information and Control Engineering · 2012
Signal-noise-ratio(or equivalently, noise variance)is needed when calculating extrinsic log-likelihood-ratio in Data-directed equalization algorithm based turbo equalization. The performance of turbo equalization system will be impacted due to SNR estimation errors while the exact SNR can not be gained in the equalization process. A simi-analytic method is proposed to research performance degradation of a DDEA based turbo equalization system due to SNR estimation errors. Comparing to these methods which analyse this problem according simulation, the proposed mathod is simpler beacause it solve this problem by calcalations. According to simulation results, the proposed method is varified, and also it is clear to observe that the turbo equalizer is quite insensitive to SNR overestimation while it is quite sensitive to SNR underestimation.