In terms of precoding techniques, Tomlinson Harashima precoding (THP) was studied in [29, 34], while linear precoding schemes such as ZF and R-ZF were evaluated in [30, 34].
The precoding in (18) is coined TPE precoding and actually defines a whole class of precoding matrices for different J.
This chapter also describes a third transmission technique, precoding, which is widely used in current and developing wireless standards, and shows that the other transmission schemes can in fact conveniently be described in terms of precoding.
We also study the precoding design to combat the numerical error of estimation for the autocorrelation matrix, and discuss the effects of precoding on channel estimation and equalization.
The proposed beamforming scheme requires only a single matrix inversion of precoding vector; however, the conventional iterative beamforming schemes requires dozens of computations for precoding vectors.
When quantized feedback is employed, the number of feedback bits determines the performance of precoding.
In LTE, the precoding matrix can be chosen from a finite set of precoding matrices [10].
Each BS performs two levels of precoding, firstly it estimates and shares only the large-scale fading coefficients with a central entity (network controller) which computes the precoding matrices and sends them back to the BSs, i.e, outer precoding.
However, let us stress that (2) has to be modified when one of the precoding techniques (including SVD method, which is a particular case of precoding) is applied.
From Proposition 1, we observe that the achievable ergodic SE of MRT precoding with the user scheduling method is identical to that of the ZF precoding [ 42 ].
