Comments on: WGSDIA – Support Open Spectrum

By: Steve Song

Steve Song — Mon, 05 Oct 2009 07:31:32 +0000

Hi Alexander. Thanks. I think the OpenBTS project is an amazing initiative and in a perfect world I would much rather deploy the Village Telco using an open source GSM base station such as OpenBTS so that we might take advantage of all the existing GSM handsets on the continent. However, GSM spectrum is pretty tightly sown-up by the existing mobile operators are unlikely to be very keen to share. With a strong regulator, you might make the case for alternative approaches in rural areas and I am definitely on the look-out for opportunities to do this but haven’t come across one yet. That said. You’re right. OpenBTS rocks!

By: Alexander Chemeris

Alexander Chemeris — Sun, 04 Oct 2009 14:48:31 +0000

Hi Steve,

You should known about OpenBTS project and its goal to considerably reduce the cost of mobile access in developing world as a whole and Africa particularly. It would be very interesting to hear your opinion on the project and it’s success probability.
Today it’s still in early stage and hasn’t yet gain support from any big company. But I believe it will be a great achievement when finished.

By: Steve Song

Steve Song — Thu, 25 Jun 2009 14:29:33 +0000

Hi Paul. Absolutely. Spectrum can be assigned geographically (local TV stations are an example) although the practice of doing that is probably not as prevalent as it should be. With newer technology such as the centralised geographic databases proposed in TV White Spaces and 802.11y one can make increasingly fine-grained assignments taking into account terrain features.

By: Paul

Paul — Wed, 24 Jun 2009 12:34:05 +0000

Excuse my ignorance but is spectrum ever allocated at a sub-national level? For example, were the USALs of South Africa allocated a band that could be reused somewhere else in the country?

I imagine there are a number of organisational/technical complexities around managing sub-national allocations and reuse.

By: Steve Song

Steve Song — Tue, 23 Jun 2009 08:37:32 +0000

@jke It is a lot better than that The White Spaces devices will multiplex using OFDM similar to WiFi 802.11n or WiMax 802.16 devices. The combination of OFDM and television frequencies mean that what the signals can’t propagate through they can often bend around whether building or even hills. Plus many of these devices will be configured to run mesh networking protocols which means they can form their own web of connectivity. Ideally they will be regulated with a higher EIRP as well which should allow about 2Mb/s over 40+ kilometres. Later on when they start integrating MIMO antennas into the devices the capacity should more than double.

And of course best of all no license required. Although that doesn’t mean a free for all. Part of the White Spaces specification is a centralised dynamic database for White Spaces devices that can make spectrum management and interference resolution much simpler.

The New America Foundation has a good backgrounder on White Spaces Devices and you can find a preliminary product spec sheet from one of the manufacturers here.

BTW, thanks for the link to the Kenya spectrum allocation chart. It is certainly an improvement on the South African version which is more cryptic and is scanned into PDF as an image not text and as such is unsearchable.

However, the real goal is for regulators to publish their spectrum assignments which designate which bands are actually in use and by whom. Why this sort of thing should be a secret is beyond me yet civil society groups everywhere struggle to get the regulator to publish spectrum assignments.