In this paper, we study Spatial Tomlinson-Harashima

Precoding (STHP). We propose a generalization of the

original structure of STHP which enables different transmission

power per antenna. The main advantage of the new scheme is

that it has a scalable structure because, despite of the variable

power per transmitter (even if some transmitters are switched

off), the precoding structure and its properties are preserved.

Next, we formulate the maximum achievable rates problem for

GSTHP and solve it numerically. In addition, we show that the

problem can be quasi-optimally solved in a closed form in a

limit case, or if some approximations are done. The solution is

found to be an antenna-selection algorithm with uniform power

allocation among the active transmitters. We finally present some

simulation results and conclusions.