1. A method for estimating characteristics of a channel, the method comprising: receiving a transmission of known reference data at a receiving device, wherein the known reference data is transmitted over the channel comprising layers that include one or more desired layers and one or more interfering layers; and determining characteristics of the channel based on the known reference data, the determining including a joint estimation of the one or more desired layers and the one or more interfering layers, and the determining including selecting certain of the layers to be estimated at each of the known reference data, selecting certain of the layers to be estimated over a range of the known reference data, selecting certain of the one or more desired layers or the one or more interfering layers to be frequency-flat in the joint estimation, wherein statistics of the frequency-flat layers are used in the joint estimation rather than instantaneous values of the frequency-flat layers, and solving an equation for the joint estimation of the one or more desired layers and the one or more interfering layers based on the selections, the selections reducing a number of unknown values in the equation.