Resilient 5G Antenna Infrastructure for Smart Cities: Redundancy, Small Cells, and Environmental Hardening

Pick any department in a city, and it’s a safe bet that it has multiple smart cities applications. Some examples:

• Sanitation departments use IoT-enabled trash and recycling compactors so they don’t waste fuel stopping by ones that don’t need to be emptied yet.
• Transportation departments use sensors in parking garages and on-street parking meters to let drivers know exactly where there open spots are. That reduces traffic and pollution because drivers aren’t circling and circling, and it provides the department with insights into turnover to pinpoint where additional parking is needed.
• Health departments use air quality sensors to identify neighborhoods where pollution is high. Then they can work with their transportation colleagues on mitigation, such as reconfiguring nearby roads to reduce gridlock and idling.
• Utility departments can equip their streetlights with sensors to ramp up illumination only when pedestrians or vehicles are nearby, thus reducing both power consumption and light pollution. Other sensors can detect flooding to enable public alerts about dangerous areas to avoid.

All of these and other applications have two things in common. The first is that those cities believe there’s a solid business case for investing in those IoT technologies. The second is a need for reliable wireless connectivity to ensure that those technologies live up to their potential and provide taxpayers with a solid return on their investment.

How to Maximize Reliability and Performance

Cities are challenging places from an RF engineering perspective. For example, tall buildings block GNSS signals and create multipath for cellular and GNSS. Cities such as Austin, Texas, and Chicago are planting trees to shade sidewalks and clean the air, but that foliage also attenuates GNSS and cellular signals, making it harder to reach parking meters and utility meters.

In the case of LTE, LPWAN, 5G, and Wi-Fi, one solution is to put the network closer to where the devices are. For example, small cells mounted on streetlights can provide better uplink and downlink budgets than traditional macro sites atop buildings. That’s particularly valuable for reaching smart meters in underground utility vaults or deep inside buildings.

Small cells get their name not only from their compact size — more like a suitcase than a refrigerator — but also for their coverage area. That’s because they use higher frequencies, such as mmWave spectrum, where signals don’t travel as far. Higher frequencies support more bits per Hertz, making small cells ideal for bandwidth-intensive applications such as backhauling high-resolution public safety cameras.

In the case of GNSS, one way to maximize reliability and precision is by using a correction service. Some use another set of satellite signals, such as L-Band services, while others use terrestrial signals, such as real-time kinematic (RTK). These services are particularly valuable for applications that require granular location data. Standard GNSS is accurate to only about 0.5 meter, while correction services can achieve centimeter-level precision.

One factor to keep in mind is that satellite-delivered correction service signals are susceptible to the same foliage and building attenuation as standard GNSS. (For a deep dive into all of the options, as well as what device OEMs need to consider when choosing a compatible antenna, see “Quick Fix: Understanding the Technologies and Business Opportunities in GNSS Correction Services.”)

Size, Spectrum, and Durability are Top Considerations

When device OEMs are choosing an antenna for smart cities applications, one common consideration is size. Smaller usually is better. For example, parking meters and utility meters are relatively small, which means limited space for the antenna and the rest of the IoT module. In other cases, a compact antenna is preferable because it’s more difficult to see, so criminals and vandals overlook that the device can be remotely monitored and controlled.

Durability also is a key requirement. If the antenna fails, so does the connection to the device and all of the applications using it. When comparing external antennas, pay close attention to the enclosure’s IP and IK specs. For example, an IP67-rated enclosure is verified to withstand up to 1 meter submersion for 30 minutes, while an IK08 rating means the antenna elements inside are protected against objects weighing up to 1.7 kg dropped from a height of 29.5 cm. (For more information, see “What Does an IP67 Rating Really Tell You about an Antenna’s Durability?” and “How IP and IK Ratings Measure Real-World Durability.”)

Those requirements are among the reasons why Taoglas developed the Colosseum Series, all of which have an IP67 enclosure. The Colosseum Combination Antenna is just 57.4 mm tall but includes 5G/4G MIMO, dual-band Wi-Fi®, and multi-constellation GNSS. The 57-mm Colosseum X active and passive antennas are ideal for GNSS-only applications that require multi-constellation resilience and precision, including optional support for L-Band correction services to achieve centimeter-level granularity.

Another tip is to ensure that the antenna’s cables and connectors aren’t weak links. The cable’s shield and jacket layers should be thick enough to protect the conductor, while the connectors should be ruggedized and, during manufacturing, tested to verify that they’re sealed tight against the cable ends. (For more insights, see “A Crash Course on RF Cables” and “What’s Inside is What Counts: Understanding Antenna Coaxial Cables.”)

Finally, many cities own and operate an electric utility. When developing smart cities solutions for those municipalities, consider choosing an antenna that covers the 900 MHz band (896-901 MHz uplink and 935-940 MHz downlink). Also known as Band 106 when it’s used for LTE and n106 for 5G, 900 MHz is ideal for applications such as smart grids because signals can penetrate foliage and reach meters inside buildings and underground utility vaults. All Taoglas cellular antennas that cover LTE Band 8 (880-915 MHz uplink and 925-960 MHz downlink) will support B106/n106, too. (For more insights, see “B106/n106: The New 900 MHz Option for Private LTE and 5G Networks for Utility Applications.”)

Get in touch for orders or any queries: sales@rfdesign.co.za / +27 21 555 8400

Courtesy of Taoglas