Question [Q] Nexus 4 KitKat. : 3G comparing to Other Mobiles

I have an interesting issue. I have 3G and 2G range in my home. But most of the time Nexus 4 will connect only to 2G (i always put 3G as preferred network mode.). It binds to 3G very very very rarely in some places!!!. But i get consistent 3G in my office or in other locations. So i was under the assumption that it was network problem near my home. But to my surprise all the other company mobiles (Samsung or Micromax etc) binds to 3G always.!!! At Same place, Same time, Same connection, other mobiles have full range 3G but nexus 4 binds only to 2G. What can be the reason...