A Robust Frequency Tracking Loop at the ENodeB for LTE Uplink

4G systems like LTE (Long Term Evolution) provide an uplink data rate up to 80 Mbps, utilize higher order modulation (64-QAM) and introduce Space Division Multiple Access (SDMA) to improve spectral efficiency. These features pose stringent frequency and time synchronization requirements for the modem to guarantee satisfactory performance. This paper presents a simple yet robust scheme to estimate the frequency offset on a per user-basis at the eNodeB. The algorithm proposed utilizes a non-coherent method to provide frequency error estimation, hence decoupled from the channel estimator.