Wcdma
ER02s16 03-12-04 12.31 Sida 16
WCDMA evolved—High-speed packet-data services
Stefan Parkvall, Eva Englund, Peter Malm, Tomas Hedberg, Magnus Persson and Janne Peisa
Compared to second-generation systems, one of the most important aspects of third-generation mobile systems is enhanced packet-data access. WCDMA Release 99 provides data rates of 384 kbit/s for wide area coverage and up to 2 Mbit/s for hot-spot areas, which is sufficient for most existing packet-data applications. However, as the use of packetdata services increases and new services are introduced, greater capacity will be required. WCDMA Release 5 extends the specification with, among other things, a new downlink transport channel that enhances support for interactive, background, and to some extent, streaming services, yielding a considerable increase in capacity compared to Release 99. It also significantly reduces delay and provides peak data rates of up to 14 Mbit/s. This enhancement, which commonly goes under the abbreviation, HSDPA, is the first step of evolving WCDMA to provide even more outstanding performance. The authors describe the basic principles used by this enhancement and how they are incorporated into the specification and products. They also explain the associated system and end-user benefits.
High-speed downlink shared channel
WCDMA Release 5 extends the WCDMA specification with a new downlink transport channel, called high-speed downlink shared channel. With shared channel transmission, a certain amount of the channelization codes and transmission power in a cell are considered a common resource that is dynamically shared among users, primarily in the time
domain. Shared-channel transmission makes more efficient use of available code resources in WCDMA. HSDPA also supports new features that rely on, and are tightly coupled to, the rapid adaptation of transmission parameters to instantaneous radio conditions: • Fast link adaptation—instead of compensating for varying
WCDMA evolved—High-speed packet-data services
Stefan Parkvall, Eva Englund, Peter Malm, Tomas Hedberg, Magnus Persson and Janne Peisa
Compared to second-generation systems, one of the most important aspects of third-generation mobile systems is enhanced packet-data access. WCDMA Release 99 provides data rates of 384 kbit/s for wide area coverage and up to 2 Mbit/s for hot-spot areas, which is sufficient for most existing packet-data applications. However, as the use of packetdata services increases and new services are introduced, greater capacity will be required. WCDMA Release 5 extends the specification with, among other things, a new downlink transport channel that enhances support for interactive, background, and to some extent, streaming services, yielding a considerable increase in capacity compared to Release 99. It also significantly reduces delay and provides peak data rates of up to 14 Mbit/s. This enhancement, which commonly goes under the abbreviation, HSDPA, is the first step of evolving WCDMA to provide even more outstanding performance. The authors describe the basic principles used by this enhancement and how they are incorporated into the specification and products. They also explain the associated system and end-user benefits.
High-speed downlink shared channel
WCDMA Release 5 extends the WCDMA specification with a new downlink transport channel, called high-speed downlink shared channel. With shared channel transmission, a certain amount of the channelization codes and transmission power in a cell are considered a common resource that is dynamically shared among users, primarily in the time
domain. Shared-channel transmission makes more efficient use of available code resources in WCDMA. HSDPA also supports new features that rely on, and are tightly coupled to, the rapid adaptation of transmission parameters to instantaneous radio conditions: • Fast link adaptation—instead of compensating for varying