Energy inefficiency could kill pure cellular

In a piece of research that could have implications for the future of mobile broadband, a US analyst firm has claimed that new mobile applications will make pure cellular technology too energy-inefficient to be practical in the future.

Instead, suggests the report by ABI Research — entitled Energy Efficiency Analysis for Mobile Broadband Solutions — operators may be forced to integrate WiMax and Metro Wi-Fi into their networks.

Noting that energy costs represent the third most expensive operating expense (OPEX) for carriers today — and that energy costs continue to fluctuate and could rise — the authors claim that the increase in data traffic resulting from the rise of mobile broadband "will push per-subscriber energy OPEX for cellular solutions past acceptable barriers".

"From a pure coverage perspective WiMax is twice as energy-cost-effective and metro Wi-Fi is 50 times more energy-cost-effective than WCDMA [a 3G network protocol]," said Stuart Carlaw, ABI's director of wireless research, on Thursday. "When data traffic is factored into the equation, WiMax can accommodate 11 times today's average data consumption and still be more energy-cost-efficient compared to WCDMA or HSDPA." HSDPA is an enhancement to existing 3G networks, which makes them significantly faster.

If ABI's predictions are accurate, there could be major implications for the cellular industry as the world moves towards greater energy efficiency and costs rise. In the UK, the industry has so far shunned WiMax, which is seen as an upstart rival to the 3G networks which have been invested in so heavily by operators.

However, Metro — or municipal — Wi-Fi is fast becoming a reality as BT rolls out its "Wireless Cities" programme across the UK. Twelve city centres should be boasting semi-ubiquitous Wi-Fi coverage by the end of March (although exactly which 12 is still unknown) and this trend spread across most of Europe over the next few years.

Although BT has more or less stayed out of the cellular fray since selling off its Cellnet (now O2) division in 2001, the ongoing upgrade of its Fusion converged offering to Wi-Fi means its customers would eventually be able to use their home or work phones anywhere throughout the covered areas — effectively making BT a limited mobile network again.

Dean Bubley, of Disruptive Analysis, also pointed out that femtocells — essentially miniature mobile phone transmitters for the home or small office — could prove another solution for operators looking to mitigate their energy costs. Noting that the devices, which are yet to be adopted by any UK operator, would see customers providing the backhaul (or underlying connection) for mobile broadband when at home, rather than the operators providing the network access, Bubley suggested on Friday that this approach could have the subscriber "paying for the power supply as well".