1. A system, comprising an integrated circuit configured to: communicate data in a channel; receive a channel matrix for the channel, wherein the channel matrix includes a plurality of columns; perform a preprocessing step, using a preprocessing circuit, to compute a plurality of preprocessed column values corresponding to respective columns; perform an update step, using an update unit, to update an estimation vector using a plurality of outer-loop iterations of an outer loop, wherein each outer-loop iteration updates the estimation vector using the plurality of preprocessed column values; and perform an access link process using the estimation vector.