SPC02-2: Joint Data Detection and Channel Estimation for MIMO-OFDM Systems via EM Algorithm and Sphere Decoding
We consider joint data detection and channel estimation for multiple-input multiple-output orthogonal frequency division multiplexing systems. The expectation maximization algorithm is employed to capture the dynamics of a time-varying fading channel and also to recover the channel input. This is done iteratively: channel estimates are updated in the E-step, whilst the sphere decoding algorithm is used in the M-step to realize data recovery. Initial channel estimates are obtained through the use of a small number of pilot symbols. We show by simulation that the performance of the proposed algorithm can approach coherent detection with reasonable computational complexity.