In the latest of their joint projects in mobile transport, Ericsson and O2 Telefónica have successfully demoed 5G wireless backhaul for rural and suburban coverage. This technology milestone has shown that the companies can deliver speeds of up to 10 Gbps over a distance of more than 10 km and demonstrate fiber-like microwave connectivity.

The result of this world-first demo showed that microwave backhaul over traditional bands can support the continued build-out of high-performing 5G networks and enhanced mobile broadband services from urban to suburban and rural areas – one of the key challenges facing communications service providers in scaling up their 5G deployment.

The shift to working from home during the Covid-19 pandemic illustrated the need for fast and reliable connectivity in non-urban environments, and the challenge has been to maintain telecom-grade availability beyond distances of two to three kilometers. The ability to deliver such high data speeds over distances of more than 10 km opens up a new world of possibilities for the delivery of low-latency, reliable broadband in harder-to-reach areas.

Traditionally, such areas have been difficult to service, as high capacities require broad bandwidths that usually only have been available in millimeter wave frequency bands (E-band). The E-band is more impacted by rain compared to the lower frequency bands, which makes it more difficult to deliver consistent service over long distances during adverse weather conditions.

In the joint demo, the key innovation is the ability to use MIMO with high modulation in the 112MHz channels (commercial MIMO solutions support up to 56 MHz channels), which were combined with Carrier Aggregation to enable similar capacities to E-band in the lower frequency bands. The demo solution has extended the hop length with extremely high capacity even in less favorable weather conditions.

The backhaul link utilized the 18GHz frequency band, dual antennas in a MIMO configuration, and commercial MINI-LINK radios together with a pre-commercial baseband algorithm that allowed the use of MIMO in 2x 112 MHz channels. MIMO ensures the efficient use of limited spectrum resources. The same capacity without MIMO would demand a 448 MHz bandwidth in a cross-polar setup.