UK-based Lime Microsystems epitomizes the hopes that 5G might usher in a new, open ecosystem and lower barriers for all. Its LimeSDR platform ticks many boxes for those hoping that the established supply chain of mobile networks will be broken apart in 5G – software-defined, open source, white box, even crowdfunded. Now it has secured an alliance with Vodafone to develop solutions based on LimeSDR, which follows on the heels of a similar deal with the UK’s leading MNO, BT/EE.
Lime’s story has a Cinderella element which seems appropriate to the operators’ quest for a new, open industry to make 5G affordable and flexible. Founded in 2005, the start-up has toiled away in RF transceivers – hardly the rock stars of the mobile value chain – innovating in programmable devices which make it easier to support many frequencies.
This has been important work, especially in LTE with its diverse spectrum choices, but Lime only really burst onto the mobile center stage last year when it launched, and crowd-funded, LimeSDR. This has brought software-defined radio (SDR) to an open source base station platform, complete with app store courtesy of a collaboration with Linux major Canonical.
Lime has run two crowdfunding campaigns. The first supported the LimeSDR board itself and achieved almost double its $500,000 target in June 2016. The second, LimeNET, surpassed its $50,000 target in July but it still open. LimeNet combines the SDR with an Intel x86 processor to create a small cell base station, a gateway or an enterprise router, though the aim is to take it into macrocells too.
Lime claims it is the first company to take SDR into base stations, with the potential to slash the cost of building a RAN and “the potential to completely transform the way telco networks run, shifting the emphasis and value away from proprietary hardware to open hardware with app stores on top”.
This will become critical because of two trends which will require a new RAN cost base – densification, using large numbers of small cells; and the wireless IoT, with its need for ubiquitous coverage, but its low ARPUs. Many operators are showing a keen interest in start-ups which promise to transform the cost of deploying mobile broadband in this way – as seen in the support for Facebook’s Telecom Infra Project (TIP), which is also working on open source, programmable, white box base stations and other equipment.
The UK’s BT has been a strong TIP backer and is currently assessing start-ups to fund within that program. And while its mobile subsidiary, EE, was the first to work with Lime, Vodafone has now added its own firepower.
The Lime partnership is part of Vodafone’s Open RAN project to explore virtualized technology. The operator will use LimeNET to bring together a group of developers to work on innovations across many areas of the RAN, including LTE, NB-IoT, mobile enterprise and future networks.
Francisco Martin, head of radio product for Vodafone Group Technology, said: “Lime Micro is at the forefront of software defined radio wireless technology development, and the platform being app-enabled brings the concepts of agile and feature-rich systems together, unlocking new applications that leverage this radio flexibility and openness to build new services and a completely different radio.”
Lime CEO Ebrahim Bushehri said in the same statement: “LimeNET is the next phase in virtualizing wireless networks and bringing products that operators can use for future real world deployments. LimeNET is aligning well with Vodafone’s Open RAN initiative to virtualize RAN functionality and enable decoupling of hardware, software and third party applications using general purpose platforms. We already have a great community developing apps, and together with innovative operators like Vodafone, with whom we demonstrated low cost radio in MWC17, we are exploring the commercialization of these platforms.”
Initiatives like Facebook OpenCellular, Vodafone Open RAN and Orange Telecom Track will send shivers down the spine of incumbent vendors, signalling MNOs’ determination to adopt a radically different cost structure for 5G, and to bring white boxes and open source into the heart of the network.
Bushehri said: “Radio access technology for wide area networks accounts for a significant portion of the overall deployment cost. We’re seeking to make the hardware an open source commodity sold for a fraction of current offerings, with the real value being in the software it runs. Doing it this way would effectively turn LTE, GSM or LoRa, or even 5G, into just an app.”
The first LimeNET product, the LimeNET Mini, is an app-enabled, small cell base station design targeted at localized IoT equipment, while the more-powerful LimeNET is for carrier-class wide area networks. EE is using it to support a ‘network in a box’ to bring cellular connectivity cost-effectively to remote areas or emergency situations. EE is partnering with several UK universities to develop these solutions.
Other applications developed by the LimeSDR community include IoT gateways, aviation transponders, smart meters, and systems for media streaming, radio astronomy, radar, drones and others.
At the heart of the platform is Lime’s LMS7002M RF transceiver, which allows the board to support a continuous frequency range from 100 Hz to 3.8 GHz, meaning it can be programmed to work with most mainstream wireless technologies including UMTS, GSM, LTE and WiFi, plus sub-1 GHz connections like Sigfox and LoRa, and personal area networks like Bluetooth, ZigBee and Z-Wave. The chip supports 2×2 MIMO. Much of the design of the board is open source, with the board schematics and layout available under a CC BY 3.0 licence, as well as the USB link and host software, and Altera’s Project Quartus software.
Under the Canonical partnership, developers are able to write and publish applications inside the Linux organization’s Snappy app store, where users can download them and then run them on their LimeSDR kits. Of course, developers are able to charge for these applications, with Canonical receiving a cut of that sale, but it seems likely that an ecosystem of free and open source apps will spring up around the LimeSDR.
The LimeSDR is supported by Lime’s Myriad-RF community, which it set up as a family of open source hardware and software projects for wireless innovation.