1. A method for reordering users in a multiuser detector (MUD), comprising: processing an incoming data stream in a parameter estimator to form an initial S-Matrix of K users; re-ordering said initial S-Matrix in a MUD ordering unit starting from a random initial column, wherein said re-ordering includes selecting, in a permute unit, said random initial column; removing in said permute unit, said random initial column from said initial S-Matrix of K users thereby forming a remaining S-Matrix array; forming in said permute unit, said permuted S-Matrix array starting with said random initial column, wherein said forming includes; from said remaining S-Matrix array, correlating in said permute unit, a sequential column; removing in said permute unit, said sequential column from said remaining S-Matrix array; adding in said permute unit, said sequential column to said permuted S-Matrix array; and repeating said correlating, removing and adding in said permute unit, for said remaining S-Matrix array thereby performing approximate diagonalization in said multiuser detector; and using said permuted S-Matrix Array in said multiuser detector and outputting an array of bit decisions to an output stage.