A Fast Partial Crosstalk Cancellation Algorithm in Xdsl Systems by Using Successive Convex Relaxation Approach

Partial crosstalk cancellation has been proposed to reduce the online complexity of crosstalk canceller in xDSL systems. However, it must have a very low pre-processing complexity to allow working efficiently in time-varying crosstalk environment. Also, much lower online complexity can be achieved by joint solution of the multi-user power control and partial crosstalk cancellation problems. Currently, this joint problem is formulated as a constrained weighted sum rate maximization problem and solved by employing Lagrange dual decomposition method. However, it suffers from applying per-tone exhaustive search method for its solution because of non-convexity of the problem. In this paper, the joint problem is reformulated as a mixed binary-convex problem by successive convex relaxation technique which can be solved by the efficient fixed point iteration method. The analytical and simulation results show that the proposed approach provides a solution with extremely low pre-processing computational complexity and quite close to the optimal solution.

Keywords:

Digital subscriber line (DSL) , partial crosstalk cancellation , multi-user power control , convex relaxation