Development of WCDMA

HSDPA and HSUPA are now regarded as the evolution direction of WCDMA.

The new modulation coding method in HSDPA will greatly improve the user data rate and throughput, which means that the spectral efficiency is enhanced. At the same time, users can get faster connection speeds. Therefore, from the operator's point of view, if compared with the existing 3G technology, HSDPA can be on the same wireless carrier service more high-speed users.

Compared with HSDPA, HSUPA provides 5.8Mbps data access to users theoretically by using more flexible NodeB scheduling and hybrid automatic retransmission technology. HSUPA is still being discussed in 3GPPR6WCDMA.

Main techniques used in HSDPA

HSDPA increases the system capacity of the network and also improves the downlink user data transfer rate. This performance is achieved because of the use of the following techniques.

Adaptive modulation and coding. The HSDPA link will adjust the modulation and coding method adaptively according to the change of the wireless Link quality, and the link adaptive modulation will ensure that the user can obtain the maximum data transfer rate, whether the user is near the base station or the edge of the cell. (Computer science)

Quick Dispatch method. HSDPA scheduling is directly controlled by the base station, unlike the WCDMAR99, which is controlled by the RNC. Closer to the air interface and shorter frame lengths make base station scheduling faster and more efficient. The information required for base station scheduling includes channel quality, terminal capacity, QoS level and available power/code source.

Fast retransmission method. In WCDMAR99, packet retransmission is controlled by the RNC. In HSDPA, the base station will provide a faster retransmission mechanism directly. At the same time, HSDPA also uses incremental redundancy technology. This technology allows the base station to only repeat the wrong part.

Main techniques used in HSUPA

Fast uplink scheduling based on BTS. Similar to HSDPA, in HSUPA, the scheduling function is performed in BTS. BTS can be based on its internal measurement/statistical information to be scheduled, can also be based on the information of the terminal feedback.

Fast data retransmission based on BTS control. In the R99 WCDMA system, the control of data retransmission is carried out in the RNC. In Hsupa, this part of the function is moved to BTS, which makes the response latency and round-trip cycle greatly reduced.

Performance of HSDPA and HSUPA

HSDPA can provide up to 10Mbps of data transfer rate, and more importantly, HSDPA can provide higher packet throughput capacity. Another important feature of HSDPA is the low downlink transmission error. For many applications, more guaranteed and shorter transmission delays are important, such as interactive games. Generally speaking, HSDPA is mainly used in the interactive and back-office traffic in QoS traffic level. HSDPA can also increase the volume of streaming traffic in shared channels, while shorter round-trip time will be beneficial to web browsing and other applications.

HSUPA Fast scheduling enables the network to respond more quickly to changes in load volumes, allocating more appropriate rates for various applications. This reduces the noise of the uplink system and reduces the system resources reserved for overload prevention.

In addition, fast retransmission and incremental redundancy retransmission can also improve the performance of the uplink. Rapid retransmission allows the network to work at higher block rate working points, which means that the power of launch can be lowered and eventually the coverage of the community can be expanded.

Network evolution from WCDMAR99 to HSDPA and HSUPA

HSDPA is completely backward and 3gppwcdmar99 compatible, in order to introduce HSDPA to existing WCDMAR99, the existing wireless access system should be upgraded to a certain extent. The original R99 and the terminal with HSDPA function can share a wireless carrier. An important feature of Nokia's WCDMA devices is its flexibility to upgrade, as long as the Nokia HSDPA solution simply upgrades the existing system. And the introduction of HSUPA is likely after the establishment of the HSDPA market.

Benefits of using HSDPA

HSDPA will optimize the network to reduce the lower cost per bit. For operators, the introduction of HSDPA will increase the capacity of WCDMA network hosting data service, enhance the spectrum efficiency, improve the utilization of ran hardware and improve the effectiveness of network construction.

HSDPA will improve the user's perception level. For ordinary users, HSDPA means higher data transfer rates, shorter service response times, and more reliable services.