I am currently wrapping up a project on Femtocell Networks in which I have been working for the past 2 years and I am therefore very interested in this kind of new access points for cellular networks. I am neither a fan nor a detractor of femtocells and, if I had to choose, I would get in the Femtocell team. However, I think there is still many issues that have to be considered about femtocells.

One of them is security, a topic about which I plan to talk here soon. I had thought abut it many times, but I got very good ideas and insights from a person at AT&T research that I met during a meeting I had with several members of the Security Research Group last week. If I happen to work on security for mobile networks anytime soon, that would most likely be one of the topics I would like to do research on. By the way, if you are reading the blog, thanks a lot for your comments and interest in my presentation. I hope to hear back from you guys soon with good news.

But today I want to focus on another aspect that interests me: alternatives to femtocells.

I have already devoted some posts on this blog to talk about Google Voice, my favorite Google Service along with Gmail. It has been widely discussed in the literature how smart-phones with wifi can be an alternative to femtocells. However, even if I can make and receive calls using Skype from my cell-phone, I want to be able to make and receive the calls from and to my cell-phone number. To give a simple example, in my current job hunt, if a recruiter/employer finds my Resume and wants to contact me by phone, I want to be able to receive calls to my phone number even if I am in an area with no signal. I do not want him to have to call me to Skype. With Google Voice I have my own phone number – with Los Angeles area code, making memories from my 2 years living there – and that is the one that I can list online and have it forwarded to my real cell-phone number when I have signal.

Another alternative, way more sophisticated and the main reason for this post, is ETSI TS 124 234, a protocol that allows inter-operation between UMTS/3GPP/LTE and WLAN – commonly know as wifi -. This means that – in simpler words – a seamless handover between cellular and wifi is possible. In even simpler words, if I am talking on the phone with my mom while going home, the moment I get into my apartment – where there is barely reception – the call is switched from the macrocell cellular network outdoors to my wifi home network without being noticeable. The call continues but now the data is being transmitted through my wifi.

This protocol proposed by ETSI probably targets European markets but I recently heard that – during the same meeting at AT&T’s Security Office – T-Mobile has successfully tested seamless handover between their 3G network and a wifi access point.

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