What we have today are a collection of research projects looking at what 5G could entail, ranging from massive MIMO to the use of mmWave frequencies. One of the risks to 5G is that LTE-A adopts some of these techniques, much as 3G boosted performance as 4G was being defined. It is certain that 5G will have to use higher frequencies than today to get the required bandwidth necessary to support such high data rates. Further cells will need to shrink significantly, to use spectrum as efficiently as possible.
According to John Spindler, Director of Product Management at TE Connectivity 5G could be ready to start implementation around 2020, but for this to happen specifications would need to defined in around a year or two from now.
Recently, TE Connectivity announced that its FlexWave Prism and FlexWave Spectrum distributed antenna systems (DAS) had been deployed for the 49th NFL championship game that took place on February 1 in Phoenix, Arizona at the University of Phoenix Stadium. The massive deployment includes 96 main hubs, 49 expansion hubs, and 225 remote antenna units to cover the stadium bowl, luxury boxes and service areas. The system supports various 700, 800, 850, 1900 and 2100 MHz LTE, CDMA, EVDO and UMTS services.
John Spindler says that going from 3G to 4G with DAS has not posed any problems and expects the same for 5G. However, before any real discussion can take place the operating frequencies for 5G need to be decided and the air interface protocol needs to be defined. Essentially DAS is ready for 5G, the radios will need to be upgraded, but most of the infrastructure in place can be reused. This is in contrast to small cells, which will struggle to cater to 5G without a hardware upgrade.