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Faculty of Engineering and Information Sciences - Papers: Part A

2008

Equalization

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Full-Text Articles in Social and Behavioral Sciences

Lmmse Turbo Equalization Based On Factor Graphs, Qinghua Guo, Li Ping Jan 2008

Lmmse Turbo Equalization Based On Factor Graphs, Qinghua Guo, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, a vector-form factor graph representation is derived for intersymbol interference (ISI) channels. The resultant graphs have a tree-structure that avoids the short cycle problem in existing graph approaches. Based on a joint Gaussian approximation, we establish a connection between the LLR (log-likelihood ratio) estimator for a linear system driven by binary inputs and the LMMSE (linear minimum mean-square error) estimator for a linear system driven by Gaussian inputs. This connection facilitates the application of the recently proposed Gaussian message passing technique to the cycle-free graphs for ISI channels. We also show the equivalence between the proposed approach …


Evolution Analysis Of Low-Cost Iterative Equalization In Coded Linear Systems With Cyclic Prefixes, Xiaojun Yuan, Qinghua Guo, Xiaodong Wang, Li Ping Jan 2008

Evolution Analysis Of Low-Cost Iterative Equalization In Coded Linear Systems With Cyclic Prefixes, Xiaojun Yuan, Qinghua Guo, Xiaodong Wang, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

This paper is concerned with the low-cost iterative equalization/detection principles for coded linear systems with cyclic prefixes. Turbo frequency-domain-equalization (FDE) is applied to systems that may contain the joint effect of multiple-access interference (MAI), cross-antenna interference (CAI) and inter-symbol interference (ISI). We develop an SNK-variance evolution technique for the performance evaluation of the proposed systems. Numerical results in various channel environments demonstrate excellent agreement between the predicted and simulated system performance. © 2008 IEEE.