Though there are other reasons why 5G might be advantageous for mobile service providers, customers and app providers, the practical reason for 5G is simply that, with global bandwidth consumption growing 78 percent, year over year, 4G networks simply will be unable to keep up.
Though 4G can be, and will be, improved, in terms of bandwidth capabilities, there are some clear limits. A few technologies, better radios and small cell architectures are key to that effort.
Among the technology improvements, many would point to MIMO radios, 256 QAM for more intense modulation and carrier aggregation (for 60 MHz bandwidth or more) as ways to get to gigabit 4G.
The 3GPP standards for 4G support aggregating up to 32 carriers for LTE. Not only does that create bigger channels that support more bandwidth, and therefore higher speeds, but doing so also increases efficiency, eliminating bandwidth that otherwise would be wasted for guard bands.
Operators are deploying massive MIMO antenna configurations with up to 128 antenna elements (64 transmit and 64 receive), which increases bandwidth by essentially creating multiple parallel channels where a single-antenna system has but one channel.
Radios also are using more heavily sectorized radios, which supply more effective bandwidth by reducing interference. Where traditionally cell tower radios have used three sectors, 4G cell sites now use six sectors or nine sectors.
Denser networks using smaller cells also are part of the solution, creating more effective bandwidth by more intensively reusing existing spectrum.
So one might ask why not simply use 4G and add more new spectrum. Part of the issue is that the 4G standard only includes frequencies up to 5 GHz, not any frequencies above that range. Standards-compliant network elements and platforms therefore cannot be purchased to support spectrum above 5 GHz.
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