Suboptimal approximations of dirty paper coding include Tomlinson-Harashima precoding ( 1971 ) and the vector perturbation technique of Hochwald et al. ( 2005 ) .
People have thought up several dirty paper codes , including Costa precoding ( 1983 ) , Tomlinson-Harashima precoding ( 1971 ) and the vector perturbation technique of Hochwald et al. ( 2005 ) .