TCM Mobile Deploy 2.4ghz Cellular Network in New York

Friend Alex Kinch brings news of TCM Mobile who have deployed a trial Cellular Network based on 2.4ghz Wifi with seamless hand-off between access points enabling metropolitan coverage:-

http://www.tcmmobile.com/about_y_technology.html

Quote:

TCM’s achievement is unique in that it has successfully solved the many challenges confronted when using unlicensed spectrum. These include interferences, seamless roaming, network design etc. TCM has deployed its network in downtown Syracuse, New York, a city well-known for introducing emerging telecommunication technologies. To date, field-testing has proven resilient and robust.

Alex interviews company president Haim Yashar here:-

http://www.alexkinch.com/features/inter ... cm-mobile/

This is interesting for me because, if the claims are correct, TCM Mobile have solved the biggest problem in WiFi based mobile VoIP and that's the access point handover. Such a technology really would make for the true "cellular" WiFi based network that no-one has yet been able to do.

That in turn opens up an interesting future possibility for GSM data/Cellular Wifi handoff for someone like Zer01.

Reply from satphoneguy on Jun 01, 2009 - 01:09 AM

unlicensed spectrum could mean 'lots of competition' if the technology itself does not become too expensive due to intellectual property issues. this could be great as it could mean much lower pricing going forward; which is definatly the big attraction of VOIP to 99.9% of the population.

i do however wonder how this will work in an indoor location that also has WiFi, bluetooth and other 2.4 ghz devices. would the stronger(in relation considering location) indoor signals not overwhelme any attempt to communicate with the towers outside. my experience in a few different cities is that MUNI WiFi networks do not work well when other WiFi signals are around; but work ok in the 'quiet' locations without of 2.4 ghz signals around.

Reply from jpdw on Jun 01, 2009 - 08:35 AM

you make a good point. The website doesn't say much about the details of what they are doing, but if they've taken mobile technology and moved the frequency then it might not know how to play well with all the other users on the 2.4 band. WiFi and Bluetooth for instance have bits in their standards to help work around their joint presence in the same bit of spectra.

The 2.4 Ghz might be "FREE, UNLICENSED" but there are strict limits on power output, so cell sites wont have anything like the reach of traditional mobile.

Presumably also they will need custom-built or at minimum retuned handsets which would also be a business challenge as people are used to a massive choice of phones.

As for seemless handoff between Wifi APs: handoff issues are often due to implementation - eg spaces between cells with no coverage or re-authentication during roaming taking longer than a voice call can tolerate etc. These can be solved in existing wifi if the product and implementation are done well and in a way to take into account the time-sensitive nature of voice traffic.

Still, its interesting, but I can't help thinking the technical & business challenges would keep this very niche. And that surely they could achieve the same service by using standards-based 802.11g? Maybe I missed something.

Reply from bigbloke on Jun 07, 2009 - 02:11 PM

We were doing seamless handover years ago Dean! mid to late 90s

The Eu funded a Research programme called ACTS (Advanced Communications Technology & Services)

The original site is long gone (infowin.org) but references still remain:

e.g.

http://www.ariadne.ac.uk/issue4/acts/

One of the demonstrators of the ACTS RAINBOW project:

http://cordis.europa.eu/infowin/acts/ru ... /ac015.htm

Was a technology demonstrator of seamless wireless bearer handover, maintaining an IP session whilst switching underlying networks - it was demonstrated by Lucent and subsequently the technology demonstrator was merged with another ACTS project (MOVE) MObile with Voice Enabled services)

ftp://ftp.cordis.europa.eu/pub/infowin/docs/fr-343.pdf

which demonstrated collaborative web browsing, VOIP enabled.

At the Telecom 99 exhibition in Geneva, on the EU stand the MOVE project team demonstrated this, and repeatedly performed what was widely believed to be the first known handovers between WLAN and HSCSD with ISDN call setup (there was no GPRS around). They used the VE-MASE technology and a modified version of "mobile aware SIP" (known as SMIP) to manage sessions.

How do I know this? Herve Muyal, Simon Rhodes, and myself did the demonstrations !

It erks me when marketteers say "they've solved the problems"

particularly when it was solved a decade ago !

I concede though that these guys may be <<among>> the first to do it commcerially, but then FRING allegedly does WIFI to GPRS / HSDPA too doesnt it ?


Regards

BB

Reply from dean on Jun 07, 2009 - 04:18 PM

Hey BB, long time no see

Quote:

It erks me when marketteers say "they've solved the problems"

There's a difference between solving a technical problem and taking a technical solution to market.

Certainly very very few have had the capability to take any of these technology solutions to market yet. That to me indicates there's still a problem, even if it's not an engineering problem.

What's required from a technology stand-point Rob, out of interest ? Something we could do here (eg, low budget) ?

Quote:

i do however wonder how this will work in an indoor location that also has WiFi, bluetooth and other 2.4 ghz devices.

A good point - WiFi is getting a bit noisy.

Reply from jpdw on Jun 08, 2009 - 08:39 PM

Quote:

A good point - WiFi is getting a bit noisy

Quote:

i do however wonder how this will work in an indoor location that also has WiFi, bluetooth and other 2.4 ghz devices.

IIRC WiFi (802.11) and Bluetooth at least have some level of co-existance in their standards but it's everything else in that band - everything from video senders through dect to alarms - that causes the issues.

Quote:

would the stronger(in relation considering location) indoor signals not overwhelme any attempt to communicate with the towers outside. my experience in a few different cities is that MUNI WiFi networks do not work well when other WiFi signals are around; but work ok in the 'quiet' locations without of 2.4 ghz signals around.

To overcome this problem, TMC would have to be allowed to transmit at higher power levels than everything else already in the ISM band. Which would lead all existing manufacturers to complain.... So I can't see it happening.

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