Systems and methods are disclosed herein to provide improved channel estimation and channel state information (CSI) transfer in a wireless data communication system, including but not limited to Multiple Input Multiple Output (MIMO) communication systems. In accordance with one or more embodiments and aspects thereof, a channel estimation and CSI transfer system is disclosed that extends and utilizes existing frame transfer elements to accomplish estimation and transfer. Such a system may offer improved capabilities such as a lower overhead CSI transfer, reduced data transfer latency, and more frequent CSI measurements.