Channel Estimation for Extremely Large-Scale MIMO: Far-Field or Near-Field?

Extremely large-scale multiple-input-multiple-output (XL-MIMO) is promising to meet the high rate requirements for future 6G. To realize efficient precoding, accurate channel state information is essential. Existing channel estimation algorithms with low pilot overhead heavily rely on the channel sparsity in the angular domain, which is achieved by the classical far-field planar-wavefront assumption. However, due to the non-negligible near-field spherical-wavefront property in XL-MIMO, this channel sparsity in the angular domain is not achievable. Therefore, existing far-field channel estimation schemes will suffer from severe performance loss. To address this problem, in this paper, we study the near-field…

• EC
  European Commission

  Award: 956256
• NN
  National Natural Science Foundation of China

  Award: 62031019
• NK
  National Key Research and Development Program of China

  Award: 2020YFB1807201