High density areas served by a large number of cell sites might not be an issue in urban locations, but it will factor in a great deal once you are traveling into and around rural areas not served by a vast number of sites.
Ecologists warn that the threat from deer to woodlands consist of a number of factors, including a reduction in the growth and density of saplings, bark damage and a change in the composition of under-storey vegetation.
In China, lightRadio Metro Radio will be deployed in busy indoor and outdoor locations, such as shopping malls and stadiums where coverage can suffer either from the large number of consumers trying to access a network, or because the density of buildings impedes the radio signal.
If you're strict about it, this type of progress fails to meet the requirements of Moore's Law, which originally set the precedent that the density of transistors on a chip (i.e. not just their total number) ought to double every two years.