Improved Channel Estimation Algorithms based on a Proposed Signal Model for PUCCH Format 3 in LTE-A

SORTD (Space Orthogonal-Resource Transmit Diversity) has already become a better way of transmit diversity for PUCCH format 3 in LTE-A [1]. SORTD technology lies in the characteristic that each antenna port transmits signal by using different cyclic shift [2] to make orthogonal each other. Using the SORTD’s feature of incoherence in different antennas, this paper proposes a special form of signal model. Based on this proposed model, we propose a low complexity channel estimator based on LS and cubic spline interpolation, and then we put a LS and DCT algorithm to improve the interpolation performance. Finally, for more accurate estimator we drive the third approach based on MMSE and DCT. A series of theoretical researches and simulation results show that all of them are suitable for the proposed signal model even in the environment of high-speed movement; especially the algorithms with DCT have a better performance.