Joint channel and data estimation for MIMO communications using sparse pilots

We present a joint channel and data estimation algorithm for communication across multiple antenna channels, and illustrate its performance by example of a 2 × 1 Alamouti Space-Time Code (STC) scheme as well as a 2 × 2 Spatial Multiplexing (SMX) scheme. The dedicated trellis tracking algorithm allows to estimate multiple channel coefficients in parallel while simultaneously performing a posteriori Probability (APP) detection of the transmitted bits. Link layer simulations show that the ergodic capacity can be gradually approached with incremental a priori knowledge, as stemming from an outer channel decoder, even in situations with very sparsely distributed pilot symbols, where conventional channel estimators would fail.