ABSTRACT
The consumption of power in the Information Communication Technology (ICT) sector especially to access network has become a major concern due to the massive expansion of Telecom networks in response to the continuous traffic growth. The worrying trend of power consumption is not only affecting the maintenance costs, but also deteriorating the environment by emitting Greenhouse Gases (GHG) into the atmosphere. The Passive Optical Network (PON) is considered as the most energy-efficient access network due to its passive nature; however, its downstream (DS) broadcast traffic characteristics lead to significant energy waste. This chapter discusses various techniques to conserve energy of PON with a focus on ITU PONs (GPON and XGPON). All the relevant techniques and their merits and demerits are explained in detail. At the end, a comparative analysis is also presented on the basis of energy saving, communication delays, complexity, and cost. Particularly, Optical Network Unit (ONU) sleep mode techniques are elaborated in detail as it is the most economical, simpler, and convenient technique to reduce power consumption of a PON network. The critical factors impacting the sleep mode performance and their optimum configuration values are also discussed at the end. Finally, this chapter is concluded with future recommendations.
