Channel estimation is a crucial task for the overall communication performance of a wireless receiver. Compared to traditional approaches the estimation of the wireless channel can be improved by using iterative estimation with feedback from other receiver components, however the VLSI implementation of such iterative channel estimation in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is challenging due to the high computational complexity. In this chapter we introduce the first ASIC for Decision-Directed MIMO-OFDM channel estimation which tracks channel variations using feedback from a decoder and supports M-QAM. Furthermore, timing and power dissipation trade-offs are analyzed.