 power consumption (W) Electricity cost (cent/kWh) 10 5G Performance Energy consumption cent/GB 10.000 1.000 0.100 0.010 0.001 3G macro 4G macro 5G macro 5G small Figure 10.65 Energy consumption in eurocent/GB. data at 0.2 cent/GB. The 5G small cell at mmWave can improve the efficiency further by a factor of 40 compared to the macrocell down to 0.005 cent/GB. 10.11 Traffic and Device Density The very high traffic density up to 1 Tbps (1000 Gbps) per km2 is one of the 5G targets. The traffic density can be increased by using more spectrum, more sites, and higher spectral efficiency. 5G brings together all these components for increasing capacity. Let us start first by estimating the highest traffic densities in the current LTE network. We exclude mass events from this calculation. We make the following assumptions for the traffic estimation: 100 000 population/ km², operator market share 40%, 5-10 GB/sub/month usage, and busy hour usage 7%. This simple calculation gives 1-2 Gbps/km2. The typical LTE network in the busy area uses 50 MHz of spectrum and 30 base station sites per km². We further assume an LTE spectral efficiency of 2 bps/Hz/cell. We also take into account that the traffic is not equally distributed between the sites. The assumption is that the highest loaded sites carry 4x more traffic than the average site. These assumptions give a capacity of 2 Gbps/km2, matching with the highest traffic densities (Table 10.22). Table 10.22 Traffic density assumptions. System parameter LTE today 5G below 6 GHz 5G at 24-39 GHz 5G at >50 GHz Spectrum 50 MHz 100 MHz 800 MHz 3000 MHz Sites 30/km2 50/km2 150/km2 300/km2 Sectors per site Spectral efficiency 2.0 bps/Hz 6.0 bps/Hz 6.0 bps/Hz 6.0 bps/Hz Traffic distribution Traffic density 1.9 Gbps/km2 13 Gbps/km2 120 Gbps/km2 900 Gbps/km2 10.11 Traffic and Device Density The capacity can be increased by fully utilizing the existing frequencies below 6 GHz for 5G. We assume that up to 200 MHz spectrum per operator is available, including some unlicensed 5 GHz band. We also 