Formation of cooperative cluster for coordinated transmission in multi-cell wireless networks

Coordinated transmission among multiple base stations (BSs) is widely considered as an efficient method to mitigate inter-cell interference in a multi-cell network. When all BSs in the network join the coordinated transmission by generating a common precoding matrix, the inter-cell interference becomes controllable. However, the complexity involved in the feedback of channel information and the computation of the precoding matrix is significant. So, we propose a cell-clustering algorithm, in which a given network is divided into several cooperative groups of BSs. In the proposed scheme, the BSs in the same cluster periodically transmit a common pilot signal. Then, each user measures the common pilot signal and reports the SINR gain that is expected when its serving cluster merges with one of its neighboring clusters. Finally, a central controller calculates the total improvement in the SINR of all users, selects a pair of clusters that have the highest improvement, and merges them into a new cluster. Simulation results show that the proposed scheme outperforms a conventional static cell-clustering scheme since the proposed scheme adaptively generates a set of clusters for the various geographical distributions of users.