DC-HSDPA (Dual Carrier or Dual Cell High-Speed Downlink Packet Access) technology has its limits and to further enhance its performance, the DC-HSDPA technology was introduced.
An advanced HSDPA+ network can theoretically support up to 28 Mbit/s and 42 Mbit/s with a single 5 MHz carrier. Doubling the bandwidth to 10MHz results in theoretically, double the sustained data rate.
High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing 3G mobile telecommunication networks using the WCDMA protocols. A further improved 3GPP standard, Evolved High Speed Packet Access (also known as HSPA+), was released late in 2008 with subsequent worldwide adoption beginning in 2010. The newer standard allows bit-rates to reach as high as 337 Mbit/s in the downlink and 34 Mbit/s in the uplink. However, these speeds are rarely achieved in practice