High-speed downlink packet access (HSDPA) technology promises to bridge the gap between 3G and the Internet, providing an overlay for the existing protocol stack that makes the delivery of high-speed data access to many users in a cell a reality. Instead of limiting high-speed data access to fewer than five users in a cell, HSDPA can deliver 384-kbit/s data to many more, maybe 30, users.
Realizing HSDPA will provide them with cost-effective high-speed data, operators are pushing for deployments. Testing of HSDPA by Cingular in their 3G trial network in Atlanta got underway for launch this year; NTT DoCoMo anticipates commercial deployment of HSDPA in its network this year and others expect to start rollouts by 2006. Some carriers, such as 02 in Europe and SK Telecom and KTF in Korea will leap from earlier releases and go directly to HSDPA for launch.
But HSPDA is not a simple software upgrade to 3G systems. In many respects, the change from Release 99 to HSDPA is as dramatic as that from voice-only GSM to EDGE: changing both modulation and the way packets are processed.
There are parts of the HSDPA standard that are relatively simple to implement using existing hardware. But, taken as a whole, HSDPA will simply break many deployed architectures and will require new hardware. Most base stations (also known as Node Bs) will need significant upgrades to cope with the increased data throughput and the consequences of moving to a more complex protocol.