Birhane Alemayoh

Fext and Alien Crosstalk Cancellation in Upstream Mimo Vdsl: Using Variational Inference Methods Birhane Alemayoh

Very high speed digital subscriber line (VDSLs) aim at providing extremely high data-rates by using frequencies up to 30MHz. Unfortunately, the use of such high frequency ranges causes significant crosstalk between neighboring twisted pairs within a binder. Far-End crosstalk(FEXT) from coordinated users and alien crosstalk that originates from outside the coordinated system are the major sources of performance degradation. The linear zero forcing receiver has been shown to be effective for the mitigation of FEXT. However, in the presence of alien crosstalk there is a significant rate gap between zero forcing receiver and the single user bound. In this book, turbo minimum mean square error receiver is proposed to multiple input multiple output VDSL system to bring the gap. The turbo-MMSE receiver is derived by using a variational free energy minimization framework. Simulation results show that the proposed iterative receiver converges after one iteration. Thus, making it a computationally viable option for VDSL systems. The analysis and simulation results also show that the signal to noise ratio of this receiver is superior to that of the classical receiver.