By Narayan Menon, Fontech
The inexorable rise in wireless capacity demand continues to place strains on bandwidth, as we move into a 5G world. On one hand, more and more users are actively using the system, and demanding continuously improved quality of experience. Adding to this is an increasingly diverse array of applications and services, with their own Quality of Service (QoS) requirements. Add in a diversity of terminal devices, and the resultant capacity demand can be expected to push or exceed bandwidth supply even in a 5G world.
Traditionally, wireless technologies have expanded capacity in three ways:
- By adding more spectrum, i.e. increasing supply;
- Via improved spectral efficiency, making better use of the spectrum that is available. This has been done via higher-order modulation schemes (packing more bits into the link), spatial multiplexing (Multiple Input Multiple Output (MIMO) and Multi-User MIMO schemes) and by use of higher spectrum bands (“fatter pipes”);
- And via spectrum reuse: dividing the network into smaller and smaller cells, and reusing wireless capacity (the same channels) over and over across a given geographical area. This provides a capacity multiplier effect, and has historically been a major contributor to capacity growth.
Spectrum sharing in unlicensed bands can significantly add to the available pool of wireless bandwidth. Swathes of spectrum are available today in unlicensed bands, governments are releasing new, lightly used bands for spectrum sharing, and new unlicensed bands are being allocated for use in 5G.
This paper discusses opportunities for use of unlicensed bands to augment capacity, several use cases that unlicensed spectrum can support, key challenges that need to be surmounted and solutions to address them.