In wireline multi carrier systems a cyclic prefix is commonly used to facilitate simple channel equalization at the receiver. The selection of the length of the cyclic prefix is a trade-off between maximizing the length of the channel for which inter-symbol interference is eliminated and optimizing the transmission efficiency. When the length of the channel exceeds that of the cyclic prefix, adaptive channel shorteners can be used to force the effective channel length of the combined channel and channel shortener to satisfy the cyclic prefix constraint. The focus of this thesis is the design of new blind adaptive time-domain algorithms for channel shortening in wireline multicarrier systems, with good convergence properties and low computational complexity.