Historically, traditional mobile networks have relied on macro-cell towers typically serving larger areas. Conventional antennas provide coverage like how a sprinkler system hydrates a wide area. A conventional base station antenna transmits a radio signal to a wide area regardless of how many users are connected. Since 5G operates on a much higher frequency spectrum than previous mobile networks, the electromagnetic wavelengths sent out have a higher capacity but a shorter range.
In order for networks to facilitate connection, small cell towers must be placed every few hundred feet and rely on existing streetlights and new utility poles. Small cells have emerged as an umbrella term for operator-controlled, low-powered radio communications equipment (base stations) that provide mobile and internet services in localized regions. Small cells typically have low visual impact and a coverage range from 10-100 meters. Over the next few years, the number of small cell installations are expected to increase to meet demands for enhanced coverage & capacity since they allow wireless devices to operate more efficiently, improve the available data rate and reduce exposure of the user.
These experimental cell towers are so small that mobile carriers can attach them to things like light poles or roof tops. Because 5G small cells cover a much shorter distance, more poles will be required, with the added challenge that each pole may only house technology for one mobile carrier. Telecoms are planning to place them in rural parts of the country with the expectation that the more antenna towers there are, the better the cell coverage will be for connectivity.
Coverage of a cellular network is not an obvious and straight forward measure. While cell coverage is typically associated with spatial dynamics pertaining to a certain geographical location, there are more complex aspects relevant to B5G systems associated with urbanization & mobility patterns. The lack of nuances and in-depth understanding of a coverage measure is clearly noticeable in the historical coverage requirements adopted by the regulators. Invariably, the percentage of coverage required in license conditions relate to where and how people live, including the spatial and temporal patterns with which people move. There is an important role for RF engineers and the research community to redefine coverage in terms that are useful and will guide the direction of new radio technologies.
The regulatory landscape for 5G continues to evolve with RF compliance measures including sizing of regions using small cells. In contrast to densely urbanized areas, rural regions with low aggregate capacity demands experience no spectral crunch as the VHF/UHF broadcast spectrum is not fully utilized. Regulatory authorities may allow use of small cells in smaller compliance zones, the the size and shape of compliance zones may be explored, evaluated and implemented according to technical standards subject to change with the ongoing evolution of smart antenna technologies & beam-forthing. Since mobile network antennas are typically directional, these changing beams require new approaches to assessing compliance as existing methods would significantly overestimate the size of the compliance zones.