Femtocells, Access Points and Convergence

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This nicely done commentary at SeekingAlpha by Paul Callahan delineates very significant differences between femtocells on one hand and consumer-level Wi-Fi access points and routers on the other. The two categories overlap because they provide wireless coverage within homes and SOHOs.


Femtocells are small base stations that attach to digital subscriber line (DSL) or cable modems while remaining elements in the cellular infrastructure. They have two main goals. One is simply to improve the generally weak inside coverage of cellular networks. They also cut costs by ferrying signals over IP networks from the end user to the switching facility, bypassing cell towers and pricier spectrum. Indeed, these widgets are great examples of convergence in action.


Wireless access points (APs) and routers, of course, already are widely deployed. They are taking on new responsibilities as VoIP and cellular increasingly share quarters in the same device. http://www.networkworld.com/news/2007/071607-dual-mode-voip.html


The femtocells, as elements of the cellular network infrastructure, use licensed frequencies and are required to monitor their environments to control interference with neighboring cellular systems. The APs and routers work with unlicensed frequencies and have no such requirements. In short, outside of some overarching regulatory requirements, Wi-Fi equipment vendors don't have to worry about their impact on neighboring networks.


Callahan makes a final point that is well worth putting on the radar screen. Essentially, he says, the femtocell vendors haven't been told precisely how to make sure that their products aren't disruptive, or precisely what represents a permissible level of interference.


BusinessWeek gets behind the business dynamics of femtocells. The piece says they are generating a lot of interest among deep-pocketed companies such as Motorola and Google. Indeed, Google is among investors in Ubiquisys, a UK-based femtocell company. More detail on that deal is available at the EETimes. BusinessWeek adds that Thomson -- the world's largest vendor of DSL modems, according to the story -- has agreed to develop the technology with Nokia Siemens Networks.


Dean Bubley posted this report from the Avren Femtocell conference in England early last month at his Disruptive Wireless site. The post, besides reporting on the founding of the FemtoForum, voices skepticism on the near-term opportunities for the technology. He gives seven reasons that the technology will be challenged, including the proliferation of home devices that don't come with femtocells, unrealistic expectations and technical concerns over the lifespan of the products, and lack of information about voice prioritization.