Facebook has outdone even Google recently, in its efforts to shake up the mobile industry and accelerate the delivery of broadband services (and its revenue generators) to the entire planet. This is no longer just about using balloons and new spectrum to push affordable wireless access to underserved communities. It is about blowing apart the traditional mobile network supply chain, and the way those networks are deployed.
First came TIP (Telecoms Infrastructure Project), a telecoms network version of its Open Compute Project to drive commoditized, massively scalable platforms. Then came its own R&D projects geared to affordable, easily deployable, but powerful open RANs, Terragraph and Aries.
And now it has announced OpenCellular, which brings the two ideas together in many ways, providing an open source platform for low cost, dense networks.
All these moves play into a new view of the mobile network and supply chain, which will be driven by virtualization, SDN, open source, IT services and a new cost base.
Low cost, commoditized and open hardware platforms will introduce new cost structures – which may benefit MNOs but will also lower the barriers to new entrants, especially as more unlicensed and shared spectrum comes into play, along with radical approaches to wholesale capacity such as bandwidth-on-demand and network slicing.
Open source in the mobile network
As the network becomes an IT service platform, most of it should be indistinguishable from IT infrastructure, goes the thinking. Cloud computing, and to some extent Wi-Fi, have shown the way to this open infrastructure, and the new ecosystems often go hand-inhand with open source software and, increasingly, hardware.
A research leader from no more subversive a company than Huawei, Peter Ashwood-Smith, recently posed the question – "could 5G be more than 90 per cent code from open source origins?" Ashwood-Smith, head of IP research at Huawei Canada and chair of the ITU’s fixed line 5G focus group, was part of an NGMN discussion about how standards processes must embrace open source. But he went further by describing an entirely open source 4G network which could be deployed today, with Linux-based eNodeB and evolved packet core, Android devices, GNU radios and an open source HSS.
In reality, this approach will take many years to become robust for commercial, large-scale networks. In the meantime, there are limits to the Facebook vision when it comes to cellular networks.
There are still those pesky cell-site antennas and radios sitting outside the vision of running everything as virtual machines on COTS servers.
They will have to become ever-more sophisticated to deliver the promises of 5G, and will remain a source of cost and vendor differentiation for a long time to come. And some network functions are just too demanding to be run on any current server platform, and will continue to need specialized hardware – though this may well come from an increasingly open ecosystem.
But it indicates the radical change of thinking which is being driven by the IT community – Intel, Cisco and others; by Facebook and Google; and even by the leading traditional mobile OEMS, led by Nokia, which are embracing cloud-type network platforms in their quest to keep their customers on board.
Facebook’s latest contribution is a shoebox-sized unit which runs open source software and is designed to be mass produced by low cost vendors. It is a modular design which is software-defined and so can support a range of current and future protocols for licensed and unlicensed spectrum.
It consists of a general baseband computer (GBC), equivalent to a baseband unit (BBU) in a mobile split architecture. This handles system functions as virtual network functions, and controls a separate subsystem with the software-defined radio, integrated analog front end, and system-on-chip functions where required, plus the antennas. The SDR and SoC versions support various open source and commercial cellular stacks.
Facebook claims its system is very ruggedized and able to work in extremes of temperature and climate, but also self-installable to reduce cost and time to deployment, especially in remote communities. Its engineering team says it has “designed an innovative mounting solution that can handle high winds, extreme temperatures, and rugged climates in all types of communities around the world. The device can be deployed by a single person and at a range of heights — from a pole only a few feet off the ground to a tall tower or tree.”
The split architecture mirrors the wider moves towards virtualized clusters of small cells, particularly to support indoor coverage and capacity. The Small Cell Forum last week published nFAPI, an extension of its FAPI interface, which allows small cells from different vendors to interoperate. nFAPI applies the idea to a centralized baseband unit (BBU) which can control a cluster of radio/antennas (theoretically in a multivendor system). Facebook’s idea is similar, but fully open source – there is clear potential here to converge its TIP-based approach with the open mix-and-match platform the Forum has espoused for years.
The platform is being design tested in Facebook’s headquarters in Menlo Park, California and, assuming it gets through that process successfully, the hardware will be open sourced too, and donated to TIP. Outdoor tests will follow later this year, and the full specs will be published during the summer via TIP. Facebook is also working with OEMs and ODMs to ensure wide availability of OpenCellular once it goes commercial.
Facebook engineer Kashif Ali wrote in a Facebook Code post: “We will continue to work on OpenCellular by iterating on the design to further reduce the cost and improve efficiency. We will collaborate on this with members of the community by soliciting feedback and ideas, and we're interested in finding new applications for the technology and want to hear ideas from the community."
The comments from Ali which will send a shiver down the spines of the MNOs include: "The hardware was designed with simplicity in mind, to encourage people to deploy their own cellular networks. Many people might not realize that running their own cellular networks is not only possible but also doesn't require substantial technical expertise."
Tell that to a cellco with a huge team of specialized radio engineers …
The new approach to mobile networks
It can be assumed that OpenCellular will be able to work as the terrestrial portion of Facebook’s various test networks involving drones or stratellites. Forrester Research principal analyst Jeffrey Hammond told NetworkWorld: “I’d expect that there will be a way to upload from an Open Cellular location to a drone, as opposed to having to create handsets that would use it directly. That way, commodity tech like cheap Android phones could easily get added to the infrastructure Facebook is building out.”
He added: “I’m sure it’s consuming a fairly large team of developers and hardware folks, but that cost is still small compared to the ad revenue that a few hundred million, or billion, additional users could drive for them.”
This is where the contrast with the MNOs is so clear – the web giants are used to making massive hardware investments, and they know how to get their money back on them, something mobile operators have yet to figure out, stuck with a direct correlation between the capacity they build and the dollars they can charge for each Gbyte and Mbps of that capacity.
Facebook and Google start from a very different place.
At the Facebook F8 developer conference in April, CEO Mark Zuckerberg outlined a 10-year roadmap to connect the whole world with its services, messages and APIs. This spans technologies at every point in the chain, including apps, robotics and artificial intelligence, but there was heavy focus on the network itself.
Like Google, Facebook presumably does not want to be a network vendor, a modern version of Ericsson, but is showing the ecosystem what can be done, and hoping OEMs – old or new – will take its ideas and turn them into large-scale commercial systems. “It is not our intent to build and maintain and deploy these networks ourselves. We want to advance the state of the art,” said Jay Parikh, VP of engineering at Facebook.
That does not mean there isn’t serious engineering effort going into the various elements of the firm’s showcase mobile network, which now includes OpenCellular alongside Terragraph, Aries and a solar-powered drone called Aquila – many of them also harnessed for its wide Internet.org initiative.
Terragraph, like Open Cellular (but more futuristic), is targeted at building low cost cellular and Wi-Fi small cells in dense urban environments.
Complementing this, in a different layer of the RAN, is Project Aries, a concept design for a Massive MIMO macrocell for rural areas.
Terragraph will make heavy use of WiGig, the Wi-Fi-like network for 60 GHz spectrum, and the nodes, which can be mounted on lamp posts or buildings, will use low cost chips and components, said Facebook.
So far so conventional in the Wi-Fi and small cell roadmaps, but Facebook claims Terragraph has an innovative routing protocol for improved collision detection and greater reliability, plus “SDN-like” cloud controllers to handle large numbers of cells efficiently and flexibly, targeting capacity where it is required at any one time. The system can support multi-Gbps links and is IPv6-only. Terragraph will be trialled in San Jose, California later this year.
The first Project Aries (Antenna Radio Integration for Efficiency in Spectrum), prototype supports 96 antennas and 24 data streams, targeting spectral efficiency of 100bits/sec/Hz. So far, Facebook has demonstrated Aries at 71bps/Hz.
By open sourcing many of its designs; developing alternatives to fiber for remote area backhaul; pushing for free or flexible spectrum such as white spaces; and working with non-traditional operators or infrastructure partners, Facebook has the opportunity to rewrite the rules for how wireless networks are built and costed, driving down the capex and opex bills and lowering barriers to entry for innovative service providers which can make a business case for targeting the unserved billions (something which is hard to do with current architectures, spectrum and revenue expectations).
Copyright © 2016, Wireless Watch
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