Low‐complexity iterative channel estimation with lattice reduction‐based detection for multiple‐input multiple‐output systems

Theoretical error for asynchronous multi‐user large‐scale MIMO channel estimation

“…Summarily, pilot contamination is caused by inter‐cell interference due to pilot reuse on adjacent cells in the channel training phase [7] and may generate poor channel state information (CSI) estimates, greatly limiting the potential of massive MIMO systems. This issue is present whenever the channel estimates is assisted by pilot sequences [8, 9]. Another alternative can be obtained via blind CSI estimation techniques, like [10], but they produce, in general, lower quality estimates.…”