LG Says LTE on Nexus 4 Due to Combo-Chip from Qualcomm
LG recently offered an explanation behind the Nexus 4's supposed support for LTE 4G networks. As it is marketed by Google, the LG-made Nexus 4 supports HSPA+ at 42Mbps, but not LTE 4G. However, the Nexus 4 is a variant of the Optimus G, which is sold by both AT&T and Sprint in the U.S. Both these carrier variants include support for LTE. Since the Nexus 4's release, some owners have discovered limited LTE support on some networks with their Nexus 4. LG explains that the reason behind the LTE capability found in the non-LTE device is simple: LTE is included on the chip from Qualcomm. "In order to provide the best possible specification for Nexus 4, LG utilised the same powerful Qualcomm Snapdragon chipset as can be found in its 4G LTE product, namely LG Optimus G," an LG spokesperson told TechRadar. "This powerful chipset is only available with a combined processor and modem and cannot be implemented separately. The modem contains 4G LTE capabilities but is only effective when combined with other essential hardware parts such as a signal amplifier and filter in order for it to work. It therefore cannot be upgraded to 4G LTE capability through software." In the U.S., the Nexus 4 works on the HSPA+ networks of both AT&T and T-Mobile USA. It does not support U.S. LTE 4G networks.
...except it does
I guess the big question is whether the phone can receive dual spatial streams (2 receive antennas on at once), since technically you need that to be up to spec on LTE. So far, results are inconclusive as to whether this is the case. If not, LG is selling a phone that isn't compliant with the LTE standard, even though it will connect to towers just fine (albeit at half the download speed of a normal LTE device). However my bet is that the DC-HSPA+ capabilities built into the N4 are enough to allow diverse receive on LTE, so...