Android dual SIM handsets - recommendations and reviews

[inquisitor]

Originally Posted by UKSTEVE

It's to stop any signal conflicts - one SIM is on 3G, the other on 2G - means they can both have best signal reception/transmission conditions. If two 3G handsets are in close proximinity, the spread spectrum nature of the signals means you get a lot more bad packets.

If it actually was a problem to establish two separate radio links on adjacent UMTS frequencies from the same handset how could DC-HSPA work which does just the same to increase bandwidth? Integrating two 3G radio modules may be a cost-related problem for budget phones but I think there's no major technical issue at all.
Also keep in mind that the 5 MHz channels of UMTS include guardbands of 580kHz at the upper and lower end. So the actual carrier bandwidth of a UMTS channel is only 3840kHz and all carriers are separated by 1160kHz which should suffice to avoid interferences.