Principles of Nonlinear MIMO Receivers

Abstract

As we have seen in the previous chapter, a linear receiver tries to reduce the impact of inter-channel interference and partially of the noise in the receive signal $\mathbf {y}(k)$ of Fig. 18.1. Next, the signal is subject to a decision also called detection to recover the QAM symbols in each component $y_{i}(k)$. Various decision strategies are known from communications theory and outlined in Part I. In this section, we will consider a Maximum Likelihood (ML) detector as a receiver. In contrast to the linear receiver, the signal $\hat{\mathbf {s}}(k)$ will be estimated directly from the receive vector

$$\begin{aligned} \mathbf {r}(k)=\left( \begin{array}{cccc} r_{1}(k)&r_{2}(k)&\cdots&r_{N}(k)\end{array}\right) ^{T} \end{aligned}$$