How to improve coverage for 5G mmWave

Not all 5G is created equal. 5G low-band operates at 600-2200 MHz, 5G mid-band at 2.5/3.5 GHz, and 5G high-band at 24-40 GHz. Low band is excellent for wireless coverage but doesn’t deliver much bandwidth. High-band (also known as mmWave, or millimeter wave) may deliver blazingly fast broadband, but a cell tower typically only covers a few hundred meters. Mid-band sits in between, striking a balance between coverage and bandwidth.

The appetite for ever-higher speeds continues unabated, so there’s been much activity around 5G mmWave. Operators have launched or are expanding their networks, and a decent selection of mobile phones is now available that supports mmWave bands. Considering the potential for delivering gigabit speeds, 5G mmWave provides data over fixed wireless access (FWA) as an alternative to fiber to the home.

The critical challenge when operating at high frequencies is the limited coverage area and the dreaded dead zones. The physics of wireless signal propagation at mmWave frequencies are different than at low or mid-bands. To mention a few:

  • Outdoors, signals do not reflect well around buildings or other obstructions such as signs and trees.
  • Indoors, the situation is better due to the presence of many reflective materials that can create greater multi-path propagation;
  • Building materials, such as brick, concrete, metal, and low-emissivity glass, limit outdoor to indoor signal penetration.

Outdoor coverage may improve by installing more base stations or small cells – but at a high cost, as each site requires a fiber optic connection for fronthaul/backhaul. Laying fiber cables in a city is expensive and a lengthy process that requires permits and digging up the ground.

Improving signal coverage with 5G mmWave distributed repeaters

Beamforming and beam refining features of mmWave repeaters digitally direct its receiver to the base station transmitter. The repeater receives the wireless signal over the air, reshapes, and retransmits a stronger signal in the desired direction to devices experiencing a coverage gap.

5G mmWave antennas may incorporate many antenna elements at its transmitter and receiver, which provide flexibility to shape the beam in the desired direction to improve the signal’s quality. Therefore, signal strength is no longer a static metric but rather more dynamic with adaptive antenna arrays.

Use cases for 5G mmWave repeaters

There are three primary use-cases for enhancing coverage with 5G mmWave repeaters:  outdoor urban mobile, in-building mobile, and fixed-wireless access:

  • Outdoor urban mobile coverage: repeaters extend coverage distance and retransmit signals around obstructions, which reduces CAPEX by decreasing the required number of 5G cell sites;
  • In-building mobile coveragemmWave signals do not penetrate buildings, so an outside-in macro-cellular approach is not practical. A rooftop or wall mounted repeater can feed repeaters located inside the building;
  • Fixed wireless accessSignal strength often degrades quickly without line-of-sight from the building to the base station. Repeaters extend line-of-sight conditions and overcome the coverage gaps by intelligently repeating signals around obstructions such as foliage, buildings, and natural terrain.

Learn more about 5G mmWave coverage

This video interview with iGR explains how wireless coverage is different at 5G mmWave frequencies and how SOLiD’s RocketWAVE 5G mmWave repeaters can extend coverage to eliminate dead zones.