Planning rules for split ratio selection in building GPON-based access networks

A dimensioning process of Gigabit Passive Optical Network (GPON) involves the selection of a split ratio that determines the allocated bandwidth per subscriber sharing a single passive optical network (PON) link (Optical Line Terminal (OLT) port). The selection of a small split ratio can be costly, whereas the selection of a higher split ratio can reduce the bandwidth allocated per subscriber and subsequently subscribers may quickly experience less quality in provisioned services. This paper aims to introduce planning rules and a mathematical model which can enable network planners, from day one, to optimally dimensioning GPON access network resources (PON link capacity, OLT's ports, splitter's ports). The mathematical model considers four parameters for optimal dimensioning GPON access network: Number of subscribers and their type, busy hour, service penetration rate and bandwidth requirement. The planning rules and mathematical model have been integrated into a software utility which we have developed to evaluate the support of next-generation services in GPON access network.