… model considered in this paper is an overlaying of femtocells … number of clusters and
rays within each cluster is modeled … Here, the two-tier network based on OFDMA technique …

… , femtocells, D2D and RRHs, UDN architecture further results to a two-tier, ie, macro-tier and
small-tier networks. … by UEs at cluster borders in the clustering schemes discussed earlier. …

… Femtocell (FC) dense exploitation imposes a novel challenge for the resource allotment in
a 2-tier network, like: (1) … OFDMA-based two-tier HetNet, with spectrum sharing between …

… Moreover, in ultra-dense networks, the energy consumed by the … PS resource allocation
scheme in a two-tier heterogeneous … conventional EH-NOMA and EH-OFDMA, respectively. …

… In this paper, improved cat swarm optimization clustering (ICSOC… In recent demand, the
development of femtocell technologies … conducted a two-tier phantom cell networks analysis with …

… algorithm for OFDMA-based femtocell HetNets, where they aim … , we study the network EE
for the downlink of a two-tier multi-… clustering, each user will be served by one BS in its cluster, …

… the user clustering process where each cluster consists of … In addition, heterogeneous
networks and OFDMA were … of two-tier heterogeneous cellular networks, with wireless backhaul …

… resource allocation approaches of femtocells were designed … There are three types of wireless
links in the two-tier networks: … Next, we form clusters, assuming that the weight of a cluster …

… In a two-tier heterogeneous cellular network [12], game … different clusters, and applied
Hungarian algorithm to allocate … in femtocell networks, and then exploited a resource optimization …

… on the density of BSs. In [14], a low-complexity approach for solving the femtocell clustering
… In [15], the authors modeled the interference network as a connected graph and proposed …