Wednesday, August 27, 2008

WiFi on the bus


Recently my Swedish friend, who now lives in Tallin, told me that he was able to access internet inside the bus. It was the SEBE wifi network that he was logged on to. It intrigued me, and so I did a little research. It turned out be that Estonia is the only country in the world, now popularly being called as E-stonia, which has almost 75% of its area covered with the WiFi network. You can easily find a hot spot in a cafe, restaurants, hotels and on streets. But being able to surf uninterrupted internet on the bus is something really cool.

Wifi (802.11) has traditionally evolved as a nomadic wireless access in the ISM band (2.4 Ghz) with limited range. Typical range of a Wifi network is around 100 meters (20dBm power). So if you to cover, lets say, 10 km stretch on a highway than, at least, 100(10000/100) Wifi access points will be required. Of course, power can be increased but its more of a regulatory issues. The biggest challenge with the Wifi is mobility. When you move from one coverage area to the another, your IP address gets changed. This breaks the IP session and the network connectivity gets lost momentarily. Therefore, if you are chatting on a Yahoo or Msn messenger, you would notice a short disconnection.

Although a new standard of the Wifi has come up (802.16n), which supports mobility through "hand offs". In a hand off IP connectivity remains unaffected even if the access point changes. This is done at the back hand network. But this is largely to be seen; how many countries would adopt it as, other broadband wireless technologies like, Wimax and LTE are also picking up.

Hat's off to E-stonia!

Ps: More on the CJ blog

2 comments:

Carl-Johan Sveningsson said...

Since WiFi isn't natively a cellular technology I think it would be messy to try to cover an area like a highway as you describe. Though you could of course use directional antennas to make the range much longer along a limited path :-P

Also, I don't think it's 75% of the actual area which is covered with WiFi, but you really can find it for free or very cheap in most restaurants, cafes and some parks. Otherwise you can also use 3G, Wimax or CDMA which I think is what the SEBE bus company uses: KÕU

Ashish Gupta said...

I guess 75 % is the area with in the city, including highways. I found this figure on a website. And regarding wifi, yes, I think using the prevalent wifi devices would be a big foolishness. But there are highways in India which have been efficiently covered with wifi. As I said before, wifi was conceived for nomadic access only.