High Speed Downlink Packet Access Principles

Data services are expected to have significant growth over the next few years and will likelly become the dominant source of 3G traffic. High Speed Downlink Access (HSDPA) provides large enhancements over Wideband Code Division Multiple Access (WCDMA) for the downlink. HSDPA was standardized as part of Third Generartion Partnership Project (3GPP) Relase S and Relase 6. The HSDPA peak date rate avoible in the terminals is initally 1.8 Mbps, and it is increasing to 3.6 and 7.2 Mbps with potentially beyond 10 Mbps. HSDPA has been designed to increase downlink packet data throughput by means of fast physical layer retransmission and transmission combining as well fast link adaptation controlled by the Node B - i. e. base transmission station (BTS). The paper covers HSDPA principles for WCDMA - the key new feature included in Relase S and enhanced further in Relase 6 specification.