Energy consumption of telecommunication access networks

Service group size 16 32 64 128 256 512 Amplifier point with fibre node 1,584 794 399 202 103 54 Number of service groups Power consumption 75% of AP [W] 45 89,100 44,640 22,410 11,340 5,760 3,015 Power consumption amplifier points [W] Power consumption 25% of AP [W] 90 Figure 19: Power consumption of amplifier points in a 25/75 % distribution at different service group sizes. A fibre node within an amplifier point feeds each service group. A typical amplifier point has a maximum power consumption of approximately 90 watts and an average power consumption of approximately 45 watts. However, not every amplifier point is equipped to the maximum. A typical distribution of amplifier points in existing HFC networks is approximately 75% with an average configuration (45 watt) and approx. 25% of a maximum configuration (90 watt) (see Figure 19) – according to different equipment manufacturers. Based on this distribution, the power consumption of the amplifier points in the different service group sizes is between approximately 3,000 watts and approximately 89,000 watts. A typical service group size today is 256 subscribers per service group, which corresponds to a power consumption of 5,760 watts. However, a data rate of 50 Mbit/s for each subscriber at all times can only be realized by a service group size of 32 subscribers or less. Service group size 16 32 64 128 256 512 CMTS 1,584 794 399 202 103 54 Number of service groups Max. number of service groups per CMTS chassis 72 22 12 6 3 2 1 Number of CMTS chassis Power consumption central office per CMTS [W] 5,760 126,720 69,120 34,560 17,280 11,520 5,760 Power comsump- tion CMTS chassis [W] Figure 20: Number of CMTS chassis and the resulting power consumption including air conditioning etc. at the central office. As mentioned above, every fibre node is connected to a CMTS – Cable Modem Termination System. According to information fromHFC equipment manufacturers, approximately 72 fibre nodes/service groups can be connected to a typical CMTS. Based on the service group size, the number of CMTS chassis needed varies between one and 22. A typical CMTS chassis has maximum power consumption of approximately 5,760 watts, including additional air conditioning etc. at the central office. This leads to a total power consumption the central office between 5,750 watts and 126 kW – depending on service group size. 22