For 5G NR to work correctly and provide the necessary signal coverage, there will be macrocells and microcells. The macrocells will operate similar to the existing 4G technologies albeit with higher order modulation up to 1024 QAM and Forward Error Correction (FEC). However, the small cells, also called Femtocells, Picocells, or Microcells will use new millimeter frequencies not used before for previous cellular connectivity.
There are slight differences in the small cells, most notably in the power levels, number of users, and the range for coverage. So, how and where they are deployed will vary based upon needs for coverage. These small cells are divided into three major categories.
Femtocells
Femtocells are basically small mobile base stations designed to provide extended coverage for residential and enterprise applications. Poor signal strength from mobile operator’s basestations can be solved using Femtocell implementation. Femtocells are primarily introduced to offload network congestion, extend coverage, and increase data capacity to indoor users.
Key features / Specifications
| Coverage area | 10 meters to 50 meters (indoors) |
| Power | Typically 100 milliwatts |
| Number of users | 8 to 16 users |
| Backhaul | Wired, fiber connection |
| Application | Indoor (primarily for indoor application, can be used for outdoor applications) |
| Cost | Low cost |
Picocells
Picocells are another category of small cells suitable for small enterprises applications for extended network coverage and data throughput.
Key features / Specifications
| Coverage area | 100 meters to 250 meters (indoors) |
| Power | Typically 250 milliwatts |
| Number of users | 32 to 64 users |
| Backhaul | Wired, fiber connection |
| Application | Indoor applications (offices, hospitals, shopping centre and schools) |
| Cost | Low cost |
Microcells
Micro cells are designed to support slightly large number of users compared to femtocells and picocells. Due to high transmission power, it is capable to cover larger cells size and suitable for application like smart cities, factories, campuses, etc…
Key features / Specifications
| Coverage area | 500 meters to 2.5 kilometers |
| Power | 2 to 5 watts |
| Number of users | up to 200 simultaneous users |
| Backhaul | Wired, fiber connection and microwave links |
| Application | Outdoor applications |
| Cost | Medium cost |
While these small cells look somewhat similar to macro cell systems, other than the differences above in power and connectivity, they also use these higher frequencies that can be in the proposed bands from 3 GHz to 6 GHz, 6 to 12 GHz, 24 GHz to 30 GHz, or higher than 30 GHz. The higher the frequency, the shorter the range for coverage.
The final determination of which mmWave bands will be used will vary by country. The core decisions as to which bands of spectrum to be used for mmWave cellular applications will be decided on a country by country basis by the individual countries themselves, but in alignment and coordination with the World Radiocommunication Conference 2019 (WRC-19) decisions. The next WRC is to be held in Sharm el-Sheikh, Egypt, from 28 October to 22 November 2019. World Radiocommunication Conference (WRC) is organized by ITU to review and as necessary, revise the Radio Regulations, the international treaty governing the use of the radio-frequency spectrum, and the geostationary-satellite and non-geostationary-satellite orbits. It is held every three to four years.
To overcome this shorter range of these mmWave carriers and the make the signal more robust even in these shorter ranges, there are several physical implementations planned, These small cells will take different forms depending upon the location for the coverage, the density of users, and the potential for signal blockage from indoor versus outdoor situations. But, there is a small cell design ready to fit any of these scenarios.
References:
metaswitch. (2019).
Rajiv. (2019). What are small cells in 5G technology. RF Page. https://www.rfpage.com/what-are-small-cells-in-5g-technology/
About the Author:
Michael Martin has more than 35 years of experience in systems design for broadband networks, optical fibre, wireless, and digital communications technologies.
He is a business and technology consultant. Over the past 15 years with IBM, he has worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin currently serves on the Board of Directors for TeraGo Inc (TGO: TSX) and previously served on the Board of Directors for Avante Logixx Inc. (XX: TSX.V).
He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology.
He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now OntarioTech University] and on the Board of Advisers of five different Colleges in Ontario. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees, in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and five certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has earned 15 badges in next generation MOOC continuous education in IoT, Cloud, AI and Cognitive systems, Blockchain, Agile, Big Data, Design Thinking, Security, and more.