… EC for each user in any cluster. For … imperfect CSI caused by the channel estimation error.
The result shows that the system performance is reduced significantly due to the imperfect CSI. …

… of CSI at the transmitter (CSIT) and whether more limited CSI … to provide good multi-user
MIMO performance. Results are … several clusters with n users in each, then within each cluster …

… same cluster, which requires full CSI. However, the full CSI feedback to the BS is not feasible
in practice due to prohibitively high feedback overhead. So we propose a user clustering …

… to estimate the CSI from RRHs within each UE’s cluster to the corresponding UE. For the
CSI of the RRHs outside its cluster, we assume that the BBU pool only has the knowledge …

… -cluster CSI, we also consider channel estimation procedure of intra-cluster CSI for a user-…
then design beam-vectors based on imperfect intra-cluster CSI. To the best of our knowledge, …

… CSI: The RA problems with the overall throughput maximization have been studied in [18]–[20].
For instance, in [18], a joint user … allocation, power allocation, and user clustering. In [20], …

… systems under imperfect CSI available at the BS and users. Considering the computational
complexity, we assume that each transmit antenna supports a cluster of users to perform …

… To obtain the achievable sum rates wrt the CSI estimation overhead and imperfect CSI,
we … the number of user groups in Theorem 1 equals to the cluster size, ie, G = M, and each …

… the users interference, we propose an efficient user clustering algorithm. Within a cluster,
we consider the user … In addition, the proposed robust PA scheme for the imperfect CSI case …

… of the outage probability of each user in every clusters. For the … We analyze the system in
the case of imperfect CSI which is … under the influence of imperfect CSI. All analysis results are …