HSDPA (High Speed Downlink Packet Access): A Simplistic View of HSDPA Architecture and Its Applications

High Speed Downlink Packet Access (HSDPA) is the new technology which is introduced in 3GPP Release 5. As the name suggests, HSDPA will enable the user to achieve high data rates in the downlink while on the move. Various methods for packet data transmission in WCDMA downlink already exist in Release'99. The three different channels in Release'99/ Release 4 WCDMA specifications that can be used for downlink packet data are: Dedicated CHannel (DCH), Downlink-Shared CHannel (DSCH), Forward Access CHannel (FACH). In many ways, HSDPA's greatest strength isn't how progressive it is, but how well it interoperates with that which has gone before. HSDPA has been developed to be backwardly compatible with existing UMTS networks, and is already consistent with 3GPP standards.