The 5G challenge will be to pinpoint the user need

The 5G will improve capacity and latency of the mobile network. The current requirements set by ITU-R push the peak data rates to 20 Gbit/s and latency to 4 ms. For consumers, this will mean faster Internet connectivity. Additionally, the 5G will introduce network solutions for the Internet of Things and autonomous driving use cases, such as device to device, extremely low latency and support for low energy communication.

There’s a hard physical limitation on how much data can be transmitted with radio channel and the mobile radio technology is already catching it. The target for spectral efficiency, how much data can be transmitted by radio channel (bits/Hz), in 5G is 30 bits/Hz for down and 15 bit/Hz for up. The same targets were set already for LTE Advanced and it’s only double from the LTE 2009.

The range of the high capacity 5G base stations will be limited.

There are only two viable options to increase the capacity (increase for download and upload speed), increase the frequency bands and decrease cell sizes to decrease competing users, which both are utilized in 5G. The new frequency bands are much higher than with 3G/4G, around 3.4-3.8 GHz, and over 20 GHz. These frequencies can transmit a high level of capacity but only for a very short range. For example, the 3 GHz bands are about the same as WiFi (2.4Ghz and 5Ghz). The 20+ Ghz already requires line of sight. Thus these will be mainly used in the urban environment where the base station deploying can be dense.

The challenge with small cell size is that the user need and the network coverage has to match with extreme detail. There will be small areas with extremely fast connectivity and areas with similar connectivity as with LTE. Additionally, the areas where people are throughout the day and week are in constant flux. This forces very complex and deep organization of base stations. The 5G challenge will be to pinpoint and monitor the user need and network bottlenecks for optimal network setup.


  1. IMT-2020 ITU-R SG05 C 40 draft 2017/11 https://www.itu.int/md/R15-SG05-C-0040/en
  2. 3GPP Release 15 http://www.3gpp.org/release-15
  3. J. Wang et al., “Spectral Efficiency Improvement With 5G Technologies: Results From Field Tests,” in IEEE Journal on Selected Areas in Communications, vol. 35, no. 8, pp. 1867-1875, Aug. 2017.

About author

Sebastian Sonntag is a doctor of technology from Aalto University Finland. He’s thesis studied mobile networks, mobile measurements and how to aggregate physical mobile radio channels. Sebastian has authored over a dozen of scientific and technical publications and one technical book. He is actively participating the community as reviewer in scientific journals and for Finnish Regulatory Authority. Sebastian has history in both Ericsson and Nokia for developing base station and mobile end-user devices communication.