An access node in a wireless communication network receives a transmission that includes first and second signals. The first and second signals may be layers of a multiple-input multiple-output transmission and may also be from first and second terminal nodes. The access node derives first and second local reference signals from the transmission received using first and second antennas and estimates channel transfer functions associated with the channel through with the transmission is received. Estimating the channel transfer function can include correlating at least a portion of an expected reference signal associated with the first signal with a corresponding portion of the first local reference signal and correlating at least a portion of an expected reference signal associated with the second signal with a corresponding portion of the second local reference signal. The expected reference signal portions used to estimate the channel transfer functions may be non-orthogonal.