The advent of 5G technology will require an unprecedented increase in the density of mobile network infrastructure, with a more expansive range of services being made available, plus an exponential ramp up in data levels. Power consumption will feature among the key performance indicators underpinning the 5G standard to a far greater degree than for previous mobile technologies, such as UMTS (for 3G) and LTE (for 4G).
Due to be introduced in the next few years, 5G mobile communications will represent a step change in data capacity compared to the previous generation. The numbers involved are quite staggering, with a 1000 fold rise in mobile data volume per geographical area (equating to 10 Tb/s/km2), plus a 1000 fold ramp up in number of connected devices to be found within such an expanse. More than 1 million connections are predicted across a square kilometre in the high density urban environments where 5G deployments will first be initiated. Despite the huge increases in terms of the total data traffic and number of connections supported, improvements in energy efficiency will mean that overall network power consumption does not rise correspondingly.
With current mobile network technologies, data transmission is the dominating factor that dictates power consumption figures. However, the longstanding direct relationship that exists between these two parameters must now be redefined in order to make 5G a reality. Without enormous improvements in energy efficiency the power needed to run 5G networks would be too great - the operational costs would be too high and the ecological impact of heightened CO2 emissions too heavy to justify the benefits derived. Any conceivable improvements to the efficiency of transceivers alone would not be anywhere near enough to mitigate the increased power requirements. Instead a whole new approach must be taken.
Energy enhancements for 5G
A number of innovative mechanisms have been identified which could permit considerable enhancements in network energy efficiency and thereby facilitate the move to 5G. Firstly, small cells will be implemented to a far higher degree than they were during the 4G era. This will shorten the distance between the user and the point of transmission, with the upshot that the power needed to transmit the signal greatly diminishes. Relocation of a large proportion of the essential network functionality into the cloud, rather than having to rely on traditional hardware, will also be instrumental here. This is expected to enable marked energy savings as well as providing the greater system flexibility that has been mandated. The implementation of massive MIMO antenna arrays will lead to a substantial lowering of path losses, allowing improvements to signal-to-noise ratio (SNR) values while simultaneously curbing energy consumption levels.
Though the energy efficiency of mobile networks has been an increasing issue with each new generation, this is destined to become even more acute as the migration to 5G takes place. ETSI, along with its key members (including the leading mobile operators), has been driving how the system architecture and functional design of 5G networks will realise the energy savings necessary for 5G to be a success. As part of its collaboration with 3GPP in defining the 5G standard, ETSI recently embarked on an in-depth research activity with the aim of establishing new metrics for energy efficiency within 5G mobile networks. The outcome of this work is expected to be published before the end of 2017.