tries larger in terms of data usage during 2018 simply because of the very large population in both countries. The fast data growth in India was enabled by the launch of a new LTE network in 2016 combined with attractive data pricing. 8.4.2 Traffic Asymmetry The traffic asymmetry between the downlink and uplink should be considered for net- work optimization. The spectrum allocation in Frequency Division Duplex (FDD) sys- tems is symmetric between the downlink and uplink, while Time Division Duplex (TDD) systems allow one to configure more capacity in the downlink direction. The average asymmetry collected from a large number of LTE networks globally is illustrated in Figure 8.7: the average asymmetry is 11:1, and it has been slowly increasing during the last few years. Therefore, TDD systems are inherently more spectrally efficient than FDD systems. The high asymmetry is mainly driven by streaming video, which is the most 8 Deployment Aspects Mobile data usage per country (region) per day China India Figure 8.6 Mobile data usage per country or region per day. Traffic asymmetry downlink:uplink Heavy data usage network Global average Figure 8.7 Downlink-uplink asymmetry in mobile data in LTE networks. typical service in LTE networks. The asymmetry can be even more extreme, as shown in Figure 8.7, in a network with heavy data usage. The asymmetry in that network is 19:1. The reason is that when customers use a lot of data, the traffic is even more dominated by video streaming, which further increases the asymmetry. If we assume that TDD uses an 80:20 split between the downlink and uplink, and if the downlink spectral efficiency is two times higher than that for the uplink, then the ratio between the downlink and uplink capacity is 10:1, matching the typical traffic asymmetry. Base Station Site Solutions Base station sites have experienced major changes during the last few years and will experience further changes during the next few years. It will have an impact on the way 8.5 Base Station Site Solutions Base stati