Could you explain what you mean? What do cellphones have to do with this?
http://www.usipv6.com/what_is_ipv6.php
"IPv6 is compatible with 3G wireless (near) broadband and has other features that support greater mobility. There will be two billion mobile phones by 2006 and (at least) two addresses are required per mobile phone, so just enabling every mobile phone will require more IP addresses than are left with IPv4. Static addresses can also double battery life by not wasting power by checking whether a call is completed so the carrier can grab back the dynamic IP address, which wastes a great deal of power."
Edit: He (the Nokia engineer didn't talk about the 50%, that's only that article) only talked about better battery life in general. Whether the 50% is true I only have that article to point to.