Sum-rate of MIMO two-way relaying with imperfect CSI

In this paper we analyze pilot-aided channel estimation for the multiple-input multiple-output amplify-and-forward two-way relay channel. We use a linear minimum mean-square estimator for estimating the composite channel at each communicating terminal and by using the notion of “worst-case noise” we derive lower-bounds for the transmission sum-rate in both directions of the established bi-directional relay link.