Channel Gain Estimation from Sounding Reference Signal in LTE

3G Long Term Evolution (LTE) technology aims at addressing the increasing demand for mobile multimedia services in high user density areas. Channel aware scheduling across wide system bandwidth is one of the key techniques enabling this goal. The Sounding Reference Signal (SRS) in uplink comes in support of this feature as its main purpose is to allow the LTE Base Station (eNodeB) estimating the UL channel of the users across the scheduling bandwidth. Therefore, SRS channel and channel gain estimators are important functions that can drive the overall performance of the system. In this paper, we study such estimation algorithms and show that SRS noise variance estimation is necessary to deliver a non-biased channel gain estimation. We suggest to provision a cyclic shift of the SRS for this purpose and show simulation results validating the performance of the proposed scheme.