New iPad Can Be Speedy Without 4G
The latest iPad supports both high-speed packet access-plus (HSPA+) and dual-cell high-speed packet downlink access (DC-HSPDA) technology. These upgraded 3G options will be the default or fall-back options for many carriers lacking or limited in 4G LTE coverage.
AT&T Inc. (NYSE: T) users will appreciate the upgrade to HSPA+ with its average 5Mbit/s to 8Mbit/s download peaks in the many parts of the country where Ma Bell doesn't yet have LTE. The iPad 2 tapped out at about 1.5 Mbit/s on average 3G downloads. (See Mapping LTE: AT&T & Verizon's 4G Footprints.)
Outside the U.S., a new wrinkle on HSPA 3G technology is being deployed. DC-HSPDA, in simple terms, involves bonding or aggregating two adjacent channels -- often 5MHz wide -- to double the capacity of a data connection to an end user.
The technique doesn't add additional capacity to the cell. It multiplexes the existing capacity to cope with bursty data traffic -- in other words, it optimizes that capacity to meet subscriber bandwidth needs. (See MWC 2010: Dual-Carrier Duel.)
Apple says that its dual-cell upgrade can support maximum speeds of 42 Mbit/s. Users will see far less speed, however, in the real world, more likely in the 10Mbit/s or less range. (See Telefónica Cranks 3G to 42 Mbit/s.)
Carriers around the world, from Telefónica SA (NYSE: TEF) in Spain, Telstra Corp. Ltd. (ASX: TLS; NZK: TLS) in Australia and EMobile Ltd. in Japan have deployed -- or are in the process of deploying -- such upgrades. (See Emobile Preps HSPA+ Launch.)
What about T-Mobile? It is not clear, however, if T-Mobile US Inc. could potentially support the iPad over its 42Mbit/s upgrade, which is marketed as a "4G" service. The technical specs suggest that the AT&T model may support LTE in the advanced wireless spectrum (AWS) band that T-Mobile also uses.
"Today, we offer several Android-powered, 4G tablets like the Samsung Galaxy Tab and the T-Mobile SpringBoard with Google," a T-Mobile spokeswoman wrote in reply to our question about this. "T-Mobile customers can also connect Wi-Fi only tablets (including iPads) to our fastest 4G speeds using the T-Mobile Sonic 4G Mobile Hotspot."
So that clears things right up.
— Dan Jones, Site Editor, Light Reading Mobile