Cell grouping and autonomous channel assignment for cooperative multi-cell MIMO systems

In this paper, we propose a three-cell network multiple-input multiple-output (MIMO) scheme to mitigate the inter-cell interference in an orthogonal frequency division multiple access (OFDMA) system with each cell using the same spectrum. One fundamental question to apply the network MIMO technique in such a high interference environment is: how many base station should coordinate together to provide sufficient signal-to-interference plus noise ratio (SINR) performance? We find that on top of the tri-sector directional antenna and fractional frequency reuse (FFR), the network MIMO based on the proposed three-cell coordination strategy can already improve SINR performance significantly compared to the 19-cell coordination network MIMO without FFR and tri-sector cellular architecture.