The objective of this optimization method is to maximize the number of subscribers covered by the ISCWs, as shown in Eq. (1). The total number of subscribers is calculated with the density of subscriber group (SG) at location i . This optimization method is mainly divided into four subsections. The first subsection presents the constraints of subscribers and the second, the constraints of OLTs, which maintain the number of OLTs in CO and the connection between OLTs and splitters. In the third subsection, the constraints of splitters, which ensure the placement of splitters,