The Femto Forum published a good technical paper comparing Wi-Fi and femtocell access in 2010. This gave a fairly balanced view of the benefits and drawbacks between the two, but focussed more on residential use and didn’t compare these solutions across a variety of different location categories. Now that femtocells are being applied more widely for enterprise and outdoor use, we’ve mapped Wi-Fi for each of these use cases/location types and considered how these factors apply.
The summary reproduced below from that report summarises the main benefits of femtocells vs Wi-Fi:
- Use with all 3G phones (not just smartphones with Wi-Fi)
- Operator managed service with Quality of Service
- Seamless service continuity with the macro network
- Ease of configuration and use
- Higher levels of security
- Better device battery life
Building on our recent classification of different off-load locations, lets consider further whether the assessment fits appropriately.
|Indoor Trusted||Home or Office|
|Indoor untrusted||Transport Hubs, Conference Centres, Pubs, Restaurants|
|Outdoor Stationary||Town centres, Outdoor shopping centres|
|Outdoor Slow Moving||Pedestrian Streets|
|Transit Systems||Trains, Planes and Ships|
Probably the most data is consumed in trusted environments, such as at home or in the office. Because this isn’t a casual relationship, it’s worth investing some time and effort to ensure you have a good service/connection and that it’s secure. Setting up and configuring the Wi-Fi on your smartphone is perhaps more likely to be worthwhile – there are clearly easy paybacks for your time and effort. The advent of WPS (Wi-Fi Protected Setup) allows you to register on a Wi-Fi access point simply by entering the WPS code number printed on the bottom of a router, rather than entering a complex password and/or other parameters.
Femtocells have made similar process with customers able to add/update access to their own femtocells through self-service webpages using only the phone number, rather than having to call an agent and wait for hours (or days) for access to be granted.
Untrusted locations are a much bigger problem. I’ve never liked the idea of entering my credit card details onto a website which I’ve only just reached through a random hotspot – these are too easy to fake. Security of your web session is also likely to be much more dubious, and the cost isn’t always necessarily much cheaper than other alternatives. I’ve also found the service levels to be highly variable in many hotels and conference centres – something you can’t do much about after you’ve bought and paid for the service.
The biggest downside of the femtocell approach for me is that these are currently all operator specific, there is no simple choice for a building owner who wants to provide their customers with an operator agnostic wireless service. Wi-Fi does provide that because it is compatible with all phones and devices, regardless of the home network operator. Perhaps a different commercial approach, such as allowing national roaming and wider open access for femtocells, would solve that problem.
Sometimes when outdoors, you might stop to make/take a call or lookup some information on your smartphone. Often, you won’t be moving – it’s difficult to read a screen and walk at the same time – so the potential to use a Wi-Fi hotspot can be attractive. There’s enough time to search one out and register on it.
Outdoor Slow Moving
But as soon as you start moving and are walking quickly past Wi-Fi hotspots, I simply don’t accept that this is a workable solution. It takes too long to re-authenticate when moving quickly between Wi-Fi access points. A more controlled solution is required which caters for session handover as you walk down the street, and detects if you are now moving more quickly – say when you drive off in your car or a bus. Here, a metro-femto solution that’s integrated into the existing macrocellular network makes most sense for me.
Transit systems, such as aircraft and ships, are being equipped with femtocells and/or Wi-Fi to provide connectivity where none existed before. (Whether this is a good thing or not is left to the reader to determine). Femtocells offer a simple and commonly understood way of charging for the service, which is treated as a roaming data service from the home network operator. The tighter control of the available spectrum also restricts abuse and allows the operator to provide a fair distribution of the available resources.
Competition between Wi-Fi and femtocells is likely to be more common in trusted environments, such as the home and/or office. When outdoors or in public areas, the benefits of security, fast handover between cells, ease of configuration and better battery life all contribute to deliver a better service for the end user.