Wave Spectrum Challenges with 5G

- Cell Densification in Urban Settings

One of the fundamental changes that 5G will bring about in the radio environment is the need for cell densification in urban settings. The imperative for this change stems from the combinations of frequency bands that 5G must use to achieve its extremely high data throughput, low latency connections and ubiquitous coverage. The higher the frequency of the radio links, the higher the data transfer rates, but the propagation and achievable transmit distance also decrease. To overcome these physical challenges, 5G uses a blend of low- and high-frequency spectrum and, in areas where propagation through obstacles buildings and trees are issues, mobile network operators are densifying their cellular network with small cells.

Licensed spectrum is a scarce resource. Mobile RAN technology has reached its limits in terms of spectral efficiency. Tighter spatial reuse enabled through cell densification through small cells has been positioned for many years as the main solution for addressing exponentially increasing mobile data usage. Yet to date, small cells have not been deployed en masse as predicted. This has left Wi-Fi, with its increasingly attractive 5 GHz unlicensed spectrum and native multioperator support, as the primary offload technology for 3G and 4G macro networks.