“…Traditionally, clustering has been proposed to achieve network stability and scalability in order to improve network performance, such as throughput, the fairness of resource distribution and load balancing, as well as the lifetime of a CH, a cluster, or a network, while providing support for routing. Various surveys has been conducted on clustering schemes in different network types (i.e., cognitive radio [47,24], mobile ad-hoc [40,42], wireless sensor [39,41,45,48,50,51], vehicular ad-hoc [43,44], Internet of things (IoT) [46,49], and 5G [30]) in the literature. This paper focuses on clustering in access networks, rather than cell clustering in core networks.…”