5G Spectrum Aggregation Will be Necessary, Not Merely Helpful

We now are entering an era of mobile communications where spectrum is not technologically determined or bounded, as once was the case. Long Term Evolution 4G, for example, can be deployed in existing 2G or 3G bands and/or new bands such as 2.6 GHz or digital dividend spectrum (700/800 MHz).

In the past, use of spectrum typically has been specified by permissible use cases or air interfaces. In the future, flexible use will prevail.

That trend will become even more pronounced in the 5G era, when a mix of low-band, mid-band and millimeter wave spectrum, plus unlicensed spectrum, will occur.

Evolutions of LTE standards now completed enable the possibility to extend the benefits of LTE-Advanced to unlicensed spectrum. “LAA and eLAA, LTE-U, LWA and LWIP, and also discusses other approaches such as MulteFire and CBRS. Momentum is building behind LAA, and LTE-U has been launched in the USA,” says the Global Mobile Suppliers Association.

Also, as LTE continues to move towards LTE-Advanced air interfaces, plus use of small cells and advanced radios, 4G networks will set the stage for the transition to 5G.

Carrier aggregation has been the dominant feature of LTE-Advanced networks, and that obviously will be a key capability for supporting 5G networks using a bewildering array of spectrum assets.

Varying numbers of carriers, and varying amounts of total bandwidth have been aggregated in trials and demos, but in commercial networks, the greatest number of carriers aggregated (where we have data) is five. Some trials and demos have aggregated up to 10 carriers, GSA says.