Lattice Blog


May a Thousand Small Cells Bloom

Wireless Backhaul
Posted 05/28/2015 by Neil Bullock

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We may be a few samples short of declaring a trend, but outdoor small cells appear to have started their (long-anticipated) emergence from concept into deployment. Looking at just the North American market, the FCC has adopted measures to speed up the environmental review process to make it easier to deploy small cells in the urban environment and service operators are now talking about their actual small cell deployments – the recent press coverage of Verizon’s deployments in San Francisco and Cleveland giving great examples. All the indications are that small cells are here to stay as part of an operator’s tool-kit for capacity expansion.

Network planning will dictate where the small cells need to be deployed – and in most cases, that location is not going to be convenient for fiber backhaul. Service operators will have to rely extensively on wireless backhaul to meet their deployment goals. In tightly packed urban environments where the cell density is highest, the arguments for backhaul in the 60 GHz band - 7 GHz of spectrum, license-free deployment, good spectrum reuse and low interference – are compelling.

So, what are the ideal characteristics of a small cell wireless backhaul link? The units must be small and light enough to be installed on street furniture such as traffic lights and lamp posts. Since installation may involve shutting down a city street, the links should be self-aligning so that they can be installed quickly without any training and be virtually maintenance-free thereafter. Finally, the units must be cheap enough to be deployed in the thousands in a single city deployment.

We’ve known for a long time that phase array antenna and electronic beam-steering technology provides a most elegant way to create backhaul links with these characteristics. Nodes are small, light, consume little power and can be built at low cost. The links are dynamic, reducing installation and maintenance costs and opening up the possibility of new network architectures. The technology is simple in concept but technically challenging to implement in practice and until recently there have been not been any real-world examples that showcase the technology.

So what’s different now? This spring, you can see the first results of the application of SiBEAM’s phase array and beam-steering technology to wireless backhaul. We’ve been working with our partner, Blu Wireless Technology to integrate our 60 GHz phase array RF transceiver together with their baseband within their Lightning demonstrator grade evaluation platform. These platforms have been installed as part of the Bristol is Open experimental network (we’ve included pictures of the installation around Bristol harbor in the UK) to demonstrate gigabit-speed wireless mesh networking for dynamic data backhaul applications. This is the first mesh network trial in Europe to use 60 GHz and OpenFlow software defined networking.

Experimental networks such as Bristol is Open are exciting indicators of the potential for 60 GHz wireless to solve operators’ data backhaul challenges. And as we continue to share more insights and developing stories on small cell deployment, we look forward to your insights and inputs into what role backhaul plays into making them bloom. Connect with us on social or by e-mail.”