Axell Wireless chose this year’s Mobile World Congress to launch its next generation DAS (distributed antenna system). The key difference to previous DAS solutions is that it is fully LTE ready and supports any LTE band around the world.
The company says the DAS system sets a radical new price point with many configurations coming out approximately 30% cheaper than current systems.
Optical master unit (OMU) II
The next-generation DAS solution is designed to help operators improve the flexibility, performance and affordability of in-building cellular coverage. At the centre of the solution is Axell’s OMU II (optical master unit II) – a hub that fully supports frequencies from FM to 2.6GHz, which covers all major LTE frequency bands worldwide.
The OMU II also supports both MIMO (multiple input, multiple output) configurations and also up to eight separate base stations – critical characteristics given that throughput data and overall capacity are essential requirement for most mobile operators in building coverage design. The OMU II works with Axell’s MBF-40 high power remotes and its new MBF-20 series of low power remotes.
‘It a rather unique architecture,’ Axell Wireless CEO Ian Brown tells Wireless. ‘It can connect and support from eight high power MBF-40 remotes up to 24 MBF-20 low power remotes. The significance of our DAS is its flexibility. You can use the high power remotes to provide coverage in a large area and the MBF-20 low power remotes to complement them in smaller buildings or offices, for example.’
MBF-20 series of remotes
The new MBF-20 series is a dual band IP65 rated DAS remote providing approximately 22dBm composite power per band in a compact approximately A4 size package. Each MBF-20 is connected to an OMU II hub via a single fibre optic cable. The MBF-20 series will be available in a variety of cellular band combinations including 850MHz/1900MHz; 700MHhz/1700MHz, 900MHz/2100MHz, and 1800MHz/2600MHz.
‘In an office people want something small and light that can be mounted on a wall,’ says Brown. ‘The MBF-20 supports two bands, but if another two bands are wanted you buy another and bolt them together to make a quad band unit and it will still run over a single strand fibre optic cable.’
DAS system are used to propagate coverage around buildings, tunnels, metros, stadiums and campus style enterprises where it does not make sense to deploy more base stations. The DAS system is fed from either a base station or an off-air repeater.
Brown says that Axell is working for LOCOG on the London Olympics where there are over 400 base stations feeding several DAS systems. ‘That’s not unusual in a stadium or big shopping centre. You need the base stations to give you the raw capacity, but the days of a base station being able to support several hundred users just using voice and text is depleting. With all these data rich hungry devices available now that is not possible.’
The remotes come in all sorts of flavours including dual band and quad band. ‘Operators are doing a lot of spectrum refarming,’ says Brown, ‘but they are not just putting all their LTE in the 2.6GHz or 800MHz bands, they are freeing up existing channels in 1.8MHz or 900MHz, so they want a product that support multiple bands.’
Low noise figure
The other significant aspect of the DAS solution is that it has a very low noise figure. The ether is full of audio signals floating around, which can be quite destructive for base stations as they interrupt the signal.
‘If you have a DAS system at the end of the remote there is a user with a cell phone connected to the base station via a DAS system, so you do not want the DAS system to introduce noise,’ says Brown. ‘If it does, it affects the base station and causes interference, which reduces its throughput and capacity.
‘So if you chose a DAS system with a high noise figure it will constrain the capacity you can get out of that base station. If there is one thing operators are worried about it is capacity. Their ARPU (average revenue per user) is going down, but the capacity on the network those customers are using is going up as they download data and use Facebook.
‘An operator want to get every ounce of capacity out of its base stations, so you want to use a low noise DAS system and we think ours is the lowest in the market. Our system, operating with one high power remote, has a noise figure of just 3db,’ says Brown. ‘That is several orders of magnitude lower than any other comparable system we are aware of.’
The benefit for the operator is that he can maximise the capacity of his base stations and the system also supports multiple base station sectors – something operators are increasingly using to increase capacity.
Auto-set up and configuration
Brown says the DAS is a high performance product, but Axell has worked at making it very easy and simple to configure. The customer simply has to go onto the internet, log in, type in the address and start the auto-configuration routine. The system automatically detects the remotes and does an auto set up. The customer can then optimise it by playing with some of the parameters.
Brown reports that the market for DAS systems is exploding, because 80% of mobile traffic now emanates from a within a building. ‘It’s a huge change from 10 years ago. Operators are building networks from the inside out now, as they are putting the effort where the demand is – inside buildings.’
Axell also provides remotes for public safety networks as well as cellular and sometimes combines the two. For example, the UK’s Heathrow Airport has an integrated system that covers all five UK mobile operators, BA, BAA, police, fire and ambulance all operating on the same integrated system.
‘The emergency services are using the 400MHz UHF band. We are the only vendor that allows you to mix and match like that, as our roots are in public safety and we are still the global leader in that,’ says Brown. ‘We have put products in the Pentagon and we are involved in the German BDBOS TETRA network being rolled out at the moment.’
Regulation helping to drive DAS market
The changing regulatory environment is also helping to drive sales, says Brown. Under European law tunnel operators have to provide public safety coverage in the tunnels. But if the operator can cut a deal with local mobile carriers, he can install both cellular and public safety equipment in the tunnel at the same time and get some return from the carriers for doing so.
In Germany, all new buildings must have emergency service coverage, while France is insisting it is rolled out in car parks. Singapore has gone even further demanding that all public buildings (and that includes apartment buildings) have to have full cellular coverage, including basements. Not only that, the operators have to complete the additional coverage within 18 months and there is a very draconian fine for operators failing comply.
Brown says Axell Wireless had a very good year in 2011 and that 2012 is looking extremely good too with a lot of demand for DAS systems. ‘I’m optimistic about it,’ he says. ‘There was a bit of a blip in spending two or three years ago, but the industry seems to have recovered and the demand is there.’
The OMU II and MBF-20 series remote are available for ordering during March with first shipments following shortly thereafter. The MBF-40 series remotes are already available for immediate ordering and shipping.