Superimposed Pilots Vs. Conventional Pilots for Channel Estimation
The authors study two competing pilot symbol based schemes, viz. Superimposed Pilots (SP) and Conventional Pilots (CP) for the estimation of a Single-Input Multiple-Output (SIMO) wireless channel. They derive expressions for the Mean-Squared Error (MSE) and Cramer-Rao Bound (CRB) of estimation of the SIMO channel. It is demonstrated that the asymptotic CRB of SP is 3dB lower than the MSE of the simplistic mean estimator. They propose a semi-blind SP scheme which asymptotically achieves this CRB. In the second part, they quantify the throughput performance of the estimation schemes by developing a framework for the worst case capacity of a channel with correlated symbols and noise.