Energy consumption of telecommunication access networks

Power consumption access network PoP size Power consumption (incl. air conditioning) per subscriber [W] Number of PoPs Number of subscribers Total power consumption P [W] 1,024 0.68 23 22,294 15,160 512 1.15 13 3,017 3,470 Total 36 25,311 18,629 Figure 26: Power consumption of the GPON access network. The energy efficiency of GPON is a multi-dimensional optimisation problem. The more GPON-ports are required, the higher the overall power consumption. However, the power consumption per GPON-port typically drops due to efficiency gains in highly densified PoP configurations. A high splitting factor – number of subscribers per GPON-port – reduces the power consumption per subscriber. Nevertheless, the minimum data rate per subscriber is reduced also. The overall power consumption (including cooling, switching etc.) of a GPON-port is, according to manufacturers’ information, between approximately 11 watts and 35 watts. An optimised GPON-PoP with a power consumption of 11 watts per GPON-port and a splitting factor of 1:5 (theoretically) has the same power consumption per subscriber as the Point-to- Point technology. The minimum data rate per subscriber however is only 500 Mbit/s in downstream and 250 Mbit/s in upstream. 6.4.3 Customer premises equipment Like the previous technologies, the FTTH technologies require customer premises equipment to establish a connection to the internet. This equipment must implement three process steps: 1. Convert the optical signal into an electrical signal 2. Establish a connection 3. Provide the connection to the user’s devices An implementation of all three steps in a single device would be ideal. However, the steps one and two are typically realized in a separated device, the so-called optical network termination (ONT). Connected to the ONT is a standard router device, often a DSL or cable device like an AVM Fritzbox 7490. The integrated modem is not necessary but needs a minimum power supply. Power consumption CPE Subscribers Power consumption per ONT [W] Power consumption per router [W] Total power consumption CPE P [W] 25,311 3.5 10 341,699 Figure 27: Power consumption of the customer premises equipment. As the Figure 27 shows, the ONT requires approximately 3.5 watts 4 . A difference between GPON and Point-to- Point devices could not be observed. The router, because it is a standard device such as for VDSL connections, requires approximately 10 watts. This means that approximately 13.5 watts are needed for a single set of customer premises equipment. For themodel region, this results in a total power consumption of 341,669 watts. 4 Measured figures. 26