Channel Estimation based Pilot Signal with BS Identification Code for LTE-TDD Massive MIMO Downlink systems

This paper presents a technique to use an orthogonality property of Hadamard code for reducing the impact of pilot contamination in LTE-TDD Massive MIMO systems. Pilot signal is modulated with Hadamard code to identify base station in cellular network. The low computational complexity suboptimal linear LS criterion is applied to estimate channel state information at base station and mitigates the effect of pilot contamination in case of full pilot reuse in multi-cell scenarios. Numerical results show that SINR performance and achievable downlink rate obtained from the proposed technique are higher than that of the LS conventional algorithm in aspect of time-varying fading channel and high cross gain of pilot power from adjacent cells.