Wcdma hspa (1)

HSPA is a new feature introduced by WCDMA R5. It uses high-order modulation of 16QAM and multi-Code Time Division Technology, greatly improving the packet transmission rate.

High-order modulation:

Higher-Order modulation can make transmission more efficient, but higher-order modulation also requires greater power and higher error rate, so higher-order modulation does not necessarily bring a high rate. However, a variable modulation method is introduced in the WCDMA system. When the system's sir is relatively good, 16aqm is used, and when the system's sir is poor. therefore, this results in a large speed increase, but it is foreseeable that the speed at the edge of the residential area is still not ideal.

Time Sharing Channel

HSPA still follows the r99 code source, so a new channel DSCH is added to increase the speed. This channel is shared, so UE can transmit data using multiple code words, which are shared by different ue usage methods. This method is designed for grouping data. When UE is surfing the Internet, traffic spikes occur most of the time, and few applications require continuous and stable data transmission like AMR services.

Channel Scheduling, hybrid ARQ and soft combine

Channel Scheduling rr

ARQ with soft combine

Chase combining

Incremental redundancy

To sum up, the new technologies introduced by HSPA are as follows:

-Higher-Order modulation (16QAM in addition to PSK ),
-Fast Link Adaptation (adaptation of transmission format to the instantaneous channel conditions, no inner-Loop
Power Control ),
-Fast scheduling taking propagation conditions into account in addition to priorities and other quality-of-service
Related Parameters,
-Hybrid Automatic Repeat reQuest (harq) with soft combining, supported by fast signaling.