4. HSDPA

• Description:
  

High-Speed Downlink Packet Access (HSDPA) is a new mobile telephony protocol and is sometimes referred to as a 3.5G (or "3½G") technology. In this respect it extends WCDMA in the same way that EV-DO extends CDMA2000. HSDPA provides a smooth evolutionary path for Universal Mobile Telecommunications System (UMTS) networks allowing for higher data capacity (up to 14.4 Mbit/s in the downlink). It is an evolution of the W-CDMA standard, designed to increase the available data rate by a factor of 5 or more. HSDPA defines a new W-CDMA channel, the high-speed downlink shared channel (HS-DSCH) that operates in a different way from existing W-CDMA channels, but is only used for downlink communication to the mobile.

• Enablers:
  
• Reference: http://en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Access