Power consumption modeling in integrated optical-wireless access network

Abstract

The access segments of both optical and wireless networks are well known for their domination over the network’s total power consumption. Therefore, the study on energy consumption particularly in integrated optical-wireless access networks is crucial as energy consumption issue is increasingly vital nowadays. Existing works to date largely addressed the physical characteristics of integrated devices and algorithms for layer 2 and layer 3, where the study in power consumption modeling was often ignored. Hence, this thesis focuses on developing a power consumption model for integrated optical-wireless access networks and investigates the energy efficiency of such networks. Gigabit Passive Optical Network (GPON) as the optical backhaul and Worldwide Interoperability Microwave Access (WiMAX) and Long-Term Evolution (LTE) with femtocell application for the wireless network are considered. First, the power consumption model of the integrated network involving Optical Line Terminal (OLT) and integration between Optical Network Unit (ONU) and Base Station (BS) known as Integrated ONU-BS (IOB) are developed. Then, the power consumption behavior of ONU under different traffic loads has been investigated to model the total power consumption of integrated access networks. An empirical approach has been proposed to characterize the power consumption of the ONU by using real GPON testbed and to develop the power consumption model of ONU based on experimental results. This is followed by the extensive analyses that have been conducted to investigate the impact of various parameters such as split ratio, Femtocell Base Station (FBS) cell range, broadcast factor, and modulation and coding scheme into the total network power consumption and energy efficiency. It has been observed that GPONLTE has the worst energy efficiency performance when compared to GPON-WiMAX, even though it offers the highest data rates. The study has been further extended by including energy saving aspects where sleep mode techniques have been applied (i.e. power shedding for the ONU and idle mode procedure for FBS) based on the user behavior from the traffic profile pattern in Cyberjaya municipal broadband access networks. The implementation of energy saving techniques have shown further significant improvement of 15% lower energy consumption for the integrated access network.