Suffering from poor quality or non-existent voice service on your mobile phone at home? We compare the three main technical solutions and consider how they have evolved in recent years.
There are broadly three technical solutions (four if you include changing network operator):
- Install a femtocell, (often termed residential small cell)
- Use Wi-Fi calling
- Install a repeater
All three technologies have evolved over recent years and are worth revisiting to assess their suitability.
Residential Small Cells/Femtocells
Naturally, this is the technical solution we would champion. Designed to provide exactly the same service and functionality as existing outdoor mobile services, these are compatible with all 3G phones and don't need any different procedures for use. Features such as voicemail, text, caller ID all work as normal. Each small cell also adds to the total capacity of a mobile network and doesn't detract or interfere with service provided to neighbours.
With some 10 million residential Femtocells deployed worldwide, the quality of service and resilience has improved. Form factor has also shrunk, driven by silicon vendors on their third generation chipsets. Firmware and software has matured in both the small cells and gateways which have increased reliability and performance since the earliest trials.
Over the last couple of years, we've now seen 4G residential femtocells become available, although they are still relatively small when measured by installed numbers. Vendors include Fujitsu, Qucell, Airvana with Alcatel-Lucent recently announcing plans for a residential product. To my knowledge, these are only deployed live in a few Asian countries (including South Korea and Japan) to date but may become more visible after VoLTE (Voice over LTE) is launched elsewhere.
One drawback with residential femtocells is that about 50% of operators insist on limiting access to a white-list of mobile phone numbers configured by the owner. In most cases, the lists can be updated online and are effective almost immediately. So although the phone users themselves do not have to take action, the femtocell owner does. Few networks seem to offer the option for open access even if the owner would want to.
Residential small cells do require an internet broadband connection. Typically 1Mbps is recommended as a minimum, but I have heard of successful use with as little as 256kbps. Typically, it's the uplink that is the limiting factor.
A few operators had provided a service called UMA (Universal Mobile Access) which connected mobile phones to the mobile core network over Wi-Fi using specifically designed protocols. This allowed the same transparent mobile service including voice and text, caller ID etc. T-Mobile USA was a major proponent as was Orange in the UK, France and Poland. However, it required specially modified phones and only a limited range of products supported it – often not the latest or most fashionable (although many Blackberrys did).
Some mobile operators allow Wi-Fi voice services using an App, which has to be enabled and open when making or receiving calls. This might be good to make outgoing calls, especially when travelling abroad, but not that useful for unexpected incoming ones. A major disadvantage has been that many of these Apps aren't integrated with the phonebook or contacts lists and can't provide the seamless and integrated no-fuss service that we'd all like.
This view may change with the integration of Wi-Fi calling within the latest Apple Ios8 release. A few operators such as EE have been working hard to enable seamless service which will appear very similar if not identical to the cellular operation today – just as UMA was. Here in the UK, this is a clear distinction between the App proviced by Hutchison 3 and EE.
While this may be more successful in locations without adequate mobile coverage but where good and easily connected Wi-Fi is available, it does rely on good Wi-Fi and so may not be quite so useful when travelling around to unknown locations. If cellular coverage is available, I'd expect most people to stick with that unless they are actively trying to avoid roaming charges in foreign countries. It will be useful in holiday homes and similar circumstances where broadband is available and a good reliable, easily connected service is available.
Unlike the previous two solutions, repeaters don't themselves add any network capacity. They also don't need any wireline or broadband internet connection to function. They do amplify a weak signal and improve service blocked by building walls or position, especially in remote rural areas. Typically, there are three components – an antenna which can be placed outside or at a window and connected to a receiver, with a relay transmitter positioned in the centre of the home. Some products require installation involving wiring of RF cables and careful positioning of the units. A few products use a wireless connection between the external receiver and relay transmitter. As a minimum, a little intelligence by the installer (e.g. homeowner) is required to position the antenna where the signal is strongest.
There are broadly three categories of repeater products:
- Some inexpensive and mostly illegal products which may benefit the owner with good cellular connection but can cause considerable disruption to the external network, impacting the service for many others. Such products are illegal and liable to enforcement action.
- A few popular and well advertised repeaters which "play within the rules". These are independent of any specific network and may support multiple network and multiple technologies (i.e. handling both 3G and 4G). These are legal in a few countries (especially North America) but may not be legal in others (e.g. Europe).
- Specifically designed repeaters which support a specific network operator and can be remotely controlled or managed to cater for situations where they are causing problems. Configuration parameters can be sent from the local basestation or via wired internet broadband to remotely limit or disable specific units. Such products may be subsidised or even provided free of charge by individual network operators to improve the service to specific customers, especially those without adequate wired broadband internet service.
Repeaters are shipping in significant volume – one vendor told me they are supplying many tens of thousands of units a month – but don't appear to be reaching quite the same volumes as residential Femtocells. Many are bought and paid for by end users, especially those suitable for multiple operators. They can cost from a few hundred dollars to several thousand. There is no whitelist and would work for anyone on the premises with any network and/or frequency that the repeater supports.
Of the three solutions available, the two factors taken most into account is who pays and who benefits.
- Femtocells are typically funded or heavily subsidised by the network operator and benefit their own subscribers - often only those configured on the whitelist for each unit.
- Wi-Fi calling will benefit those who are able to easily connect to a Wi-Fi hotspot (not always that easy) and who have enable that feature in a device which supports it. The quality of the Wi-Fi service needs to be good to make this worthwhile – something that's not always the case when away from home and office.
- Repeaters are usually bought by residents and businesses unhappy with the cellular service they receive. Multi-operator units would be most popular but are not legal in many countries. They don't directly add extra network capacity and can disadvantage other users on the same network, prioritising the lucky few over others. However they would be an ideal solution in remote locations where wired broadband isn't available.