What about backward compatibility?

A few months ago, B-Mobile decided to change the band used for its 3G mobile broadband service in Thimphu from the standard 2100 MHz to the less-popular 850 MHz. Reducing the frequency improves reception and speed. 2100 MHz (known as Band I) is the original and still most popular 3G frequency being used in the world. All smartphones and data-cards with 3G capabilities support 2100 MHz. In contrast, many existing devices do not include 3G support for 850 MHz (known as Band V).

While I was waiting today at the Bhutan Telecom office for a technician, a number of customers arrived, complaining that 3G no longer works on their phone in Thimphu, although it does work in Paro. One lady was carrying a Blackberry phone. It has become useless in Thimphu. Another was carrying a Nokia phone. A third was using Samsung Galaxy S. My own Huawei E160G data-card is not working anymore - it does not support 850 MHz. I am sure that there are many more customers who will now need to replace their mobile phones or data-cards.

Imagine BPC changing the voltage in your home's sockets from 220V to 110V. Time to replace your refrigerator and rice cooker! A mobile operator must ensure that existing devices will continue working, even in the face of network upgrades. A provider cannot expect its customers to lose their investment. The good news is that a solution is available: mobile operators can provide dual-carrier technology, where both 2100 MHz and 850 MHz work side-by-side. That will enable existing users to keep using their old equipment. I am not sure while B-Mobile did not choose this graceful route.

Upgrading the network is commendable. And 850 MHz is indeed an improvement over 2100 MHz. But providers must ensure that their customers' existing investment in equipment will not go down the drain.