The so called High-Speed Access Plus (HSPA+) network will be similar to the 4G network from Sprint, it will get closer to 10 Mbits/Sec.  T-Mobile USA plans to launch the first smartphone for its newly upgraded networked in September.

The handset is understood to be the world's first HSPA+ smartphone, and it will be the first phone that is made to handle T-Mobile's upgraded 3G network with peak downlink network speeds of up to 21 Mbit/s.

The upgrade effort is a cornerstone of T-Mobile's growth strategy in the US. The fourth largest US operator has already rolled out the 3G upgrade across 25 markets, covering 75 million people, and plans to cover 185 million people by the end of this year.

source: lightreading