A Matrix Scheme to Extrapolation and Interpolation for a 4G MIMO OFDM System

An estimation technique for Time-Invariant (TI) channels that utilizes an Extrapolation Matrix (EM) and specially designed pilot sequences is presented. We address the topic of pilot aided multi-user channel estimation for a proposed wireless system that uses OFDM in a synchronous SDMA environment, which can also be regarded as a Multiple-Input Multiple-Output (MIMO) environment. Unlike most multi-user channel estimation methods in the literature, the EM method does not assume that the number of utilized subcarriers is equal to the OFDM FFT size. Also, a matrix based channel interpolation method is described for Time-Varying (TV) channels: Windowed DFT Interpolation. Simulation results show that performance of our methods equal that of current technologies, but the computational complexity is significantly reduced.