Ericsson: Wireless backhaul comparable to fibre in small cells

Ericsson said wireless backhaul is as effective as fibre in non-line-of-sight (NLOS) small cells used in heterogeneous networks (hetnets) in licensed spectrum up to 30 GHz.

The Sweden-based infrastructure company tested two different NLOS wireless backhaul solutions: one high-end point-to-multipoint microwave backhaul; and an LTE-based point-to-multipoint concept. Each version was tested at 6 GHz and 28 GHz to allow for use of higher frequencies in future, and the tests were conducted in two 'virtual' cities to simulate real-world conditions.

Ericsson explained that existing proprietary wireless backhaul set-ups typically operate in "licensed and unlicensed spectrum in the crowded sub-6 GHz frequency range." However, small cells will increasingly need to utilise "additional spectrum at higher microwave frequencies" to handle "predicted traffic load increases."

For its tests, Ericsson assumed each technology was utilising licensed microwave bands. The performance of each technology was measured against a baseline based on fibre backhaul.

In testing designed to simulate European networks, the company found that the performance of point-to-point and point-to-multipoint wireless backhaul is broadly in line with fibre alternatives, with throughput dipping equally across all the technologies as the amount of traffic served per user/month increases.

The company said its tests prove that NLOS wireless backhaul can be achieved using point-to-point and point-to-multipoint approaches, which offers key benefits including the ability to utilise the same wireless technology for access and backhaul, leading to improved spectral efficiency that could be a bonus for 5G networks. Ericsson added that the ability to exploit the spectrum potential offered by higher frequency bands from 10 GHz to 100 GHz is part of ongoing 5G research.

Another benefit is that operators can use the same operations and maintenance system for access and backhaul, to improve system performance and simplify system management. A more obvious benefit is simply a reduction in the cost of deploying hetnets by cutting the number of small cell sites required.

ABI Research recently forecast that spending on small cell radio access networks will hit $2.1 billion (€1.6 billion) in 2014.

For more:
- read Ericsson's full report [PDF]

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