Title :
Performance analysis of the MAP equalizer with a priori and distribution of the extrinsic LLRs
Author :
Sellami, Noura ; Roumy, Aline ; Fijalkow, Inbar
Author_Institution :
ISECS, Sfax, Tunisia
Abstract :
To combat the effects of intersymbol interference, the optimal equalizer to be used is based on maximum a posteriori (MAP) detection. We consider the case where the MAP equalizer is provided with a priori information on the transmitted data, as in a turbo equalizer. We propose to study analytically the impact of the a priori on the MAP equalizer performance. We distinguish two cases: the case of unreliable a priori and the case of reliable a priori. We show that when the a priori is reliable, it is better to perform the detection of the transmitted symbols based on the a posteriori outputs of the MAP equalizer rather than on the a priori only. In a turbo equalizer, the equalizer and the decoder exchange extrinsic log likelihood ratios (LLRs). We propose here to study analytically their distribution. The aim of this study is to perform in the future the analytical convergence analysis of turbo equalizers using the MAP equalization.
Keywords :
data communication; equalisers; intersymbol interference; maximum likelihood detection; maximum likelihood estimation; turbo codes; MAP equalizer; a priori information; convergence analysis; data transmission; extrinsic LLRS distribution; intersymbol interference; log likelihood ratio; maximum a posteriori detection; performance analysis; transmitted symbol detection; turbo equalizer; AWGN; Additive white noise; Bit error rate; Convergence; Decoding; Equalizers; Error analysis; Intersymbol interference; Performance analysis; Viterbi algorithm;
Conference_Titel :
Signal Processing Advances in Wireless Communications, 2005 IEEE 6th Workshop on
Print_ISBN :
0-7803-8867-4
DOI :
10.1109/SPAWC.2005.1506043