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A guide to indoor mobile boosting technology in the UK

A guide to indoor mobile boosting technology in the UK

Making a phone call, sending an email, or accessing the web from our mobile devices is a pretty basic need for humans these days, be it at home, a public venue or in the office, yet the ability to do so inside many buildings is a constant struggle and growing problem.

Densely populated cities, modern building materials and available radio spectrum all play a part in our ability to make a phone call when inside.

It’s become apparent over the last 10 years that Mobile Network Operators (MNO’s) are less willing to fund installation of systems for mobile coverage inside the majority of buildings This has spawned the age of neutral hosts – independent companies who install a single common system which all MNO’s join, the infrastructure of which is paid for by the building owner or tenant to ensure they have guaranteed voice and data (3G & 4G) throughout their development.

Typically, these technologies are installed into new buildings as there is budget available within the scope of the development and it’s far easier to install the likes of ceiling mounted access points / radio antennas before a ceiling has been closed up.

To assist the construction and real estate industry, specifically from the perspective of design, space, power, and end user experience, we’ve put together a guide to available technologies to deliver indoor mobile boosting in the UK as well as some innovations from Vilicom which simplify any of these variants through our cloud Open Radio Access Network (Open RAN)

  • Off-air Repeaters: in 2018 Ofcom changed the law, allowing ‘some’ off-air repeaters to be used to deliver indoor mobile coverage. At present, Cel-Fi by Nextivity is the only Ofcom compliant repeater on the UK market. This technology draws signal from the outside using a ‘donor antenna’ which then travels via coaxial cable to a ‘network unit’ which then distributed the radio frequency (RF) signal via cat5/6 terminating at a ‘coverage unit’ (access point) which will be installed visibly in the ceiling and radiating the MNO of choice. To deliver more than one MNO, an overlay system is required, essentially doubling, triple or quadrupling the hardware, dependant if 1, 2, 3 or 4 MNO’s are required. A repeater will deliver coverage only, not capacity and if the signal strength or quality outside is poor, the experience inside will also be poor.
  • Passive Distributed Antenna System (DAS): Traditionally, a passive DAS utilises an MNO supplied Base Transceiver Station (BTS) and dedicated fibre backhaul which acts as the radio access network, connecting directly into the MNO core, providing dedicated capacity to a building; the MNO BTS connects to a passive Point of Interface (POI) and DAS head end via coaxial cable, which then distributes the RF signal through fibre to active Radio Remote Units (RRU’s) and from there to radio antennas using coax or, directly from the DAS head end to radio antennas using only coax. Each MNO BTS will require a minimum of 47U of cabinet space, plus an additional 47U for the POI ad DAS head end. This equipment room will require dedicated cooling and variants of power requirements for each MNO ranging from 32 amp single phase right up to 64 amp three phase. A passive DAS is a lower cost technology, however, as the majority of components are passive, there is little in the way of remote monitoring and reporting as the systems doesn’t have a great deal of intelligence. It should also be noted that each time coax is split, the signal weakens, so a passive DAS is not suited to very large buildings, say, over 500k sqft.
  • Active Distributed Antenna System (DAS): An active DAS traditionally has a similar set up to a passive DAS, except it utilises a fibre and cat6 infrastructure and by its nature, provides comprehensive remote monitoring and analysis of the DAS performance, right down to the RRU, DAS head end and secondary hubs. From the POI within the MER (Main Equipment Room), the DAS head typically connects to secondary hubs (a bit like a switch) via fibre which distributes the RF signal via cat 6, terminating at the integrated RRU’s / antennas, visible in the ceiling. Some hybrid DAS may terminate at small RRUs via fibre which then distribute signal through coax to passive radio antennas, visible in the ceiling. Dependant on the size of a building, an active DAS is typically the higher end of the scale in terms of cost, however, it will deliver a premium service in terms of RF distribution as there is very little signal loss, even in very large buildings. It also provides the best remote monitoring which is advantageous from a maintenance perspective.
  • Small Cells: Small Cells are among the newest technology to grace our industry and hold a lot of promise to simplify the installation of in-building mobile coverage, making the deployment more akin to that of WiFi, utilising PoE switches, interconnecting fibre, internet backhaul and cat6 to access points visible in the ceiling. Small Cells do not utilise a BTS like passive and active DAS, so there is very little MER space required, simplifying power requirements to a 3 pin plugs and typically lowering the cost compared to a DAS solution as there is less hardware involved and a simplified installation process. The problem to date is that the MNOs have not agreed on a single small cell vendor and in some cases have not even approved a 4G small cell, let alone a 5G unit. Some neutral hosts have done well winning market share deploying indoor 3G small cells, one per MNO from different vendors, however, the technology was not designed to be deployed together in quantity and can produce scrambled codes past 6 small cells. It can also be subject to circuit switch fall back whereby a mobile device favouring 4G and will failover to the outside network in the event of a faint signal, rendering the 3G small cells useless. A promising technology with more work required from the mobile industry!


Vilicom Innovation

All of these technologies have a place within the built environment and Vilicom have looked to simplify their delivery, connecting to the MNO’s core through a cloud, Open based Radio Access Network (Open RAN) platform, we call ‘Connectivity as a Service’ (CaaS).

Vilicom’s mobile operator approved CaaS platform allows us to install 4G & 5G Small cells as well as passive and active DAS from multiple hardware vendors at a reduced cost & cabinet footprint, with simplified power and no dedicated cooling, all while increasing our speed of delivery.

For an active or passive DAS, our cabinet footprint is reduced from 188U to just 6U and for small cells we need just 2U of cabinet space and a 3 pin plug for power. A huge step forward for the telecoms industry and of massive benefit to developers, landlords, architects, and tenants.

Vilicom are proud to be the UK’s first service provider to gain MNO approval for a virtualised Open RAN platform, providing us with the most technologically advanced and commercially beneficial indoor mobile boosting offering on the market.


Vilicom: Unleashing Mobile Connectivity.


Liam Graham – Senior Sales Manager UK - +44 7597 800622

Gearoid Collins – Director of Sales and Marketing UK - +44 7407 810619