Type 3 Advanced Receivers
The 3GPP modem categories define an upper bound on the performance that can be achieved by an HSPA modem. However, different modems from the same category can have significantly different performance in the field. This is particularly noticeable for HSDPA, where the modem must recover high-speed data from a signal that may have been heavily distorted in transit from the base-station by reflections from buildings, the influence of radio noise and the effect of the user’s motion.
In Release 99 channels, a rake receiver will give very good performance and is the most commonly used front-end architecture. However, as the spreading factor is reduced and the modulation order is increased it can, in some channels, limit throughput. Receive diversity and equalization have been shown to significantly enhance modem performance in HSPA categories and the 3GPP specification sets out performance requirements based on these techniques as follows:
- Enhanced Type 1 defines performance for UEs which utilize receive diversity
- Enhanced Type 2 defines performance for UEs which utilize chip level equalization
- Enhanced Type 3 defines performance for UEs which utilize receive diversity and chip level equalization
Livanto® ICE8020 is the world’s only Enhanced Type 3 solution for 3.6Mbps HSDPA.
As well as supporting Enhanced Type 3 performance requirements, Icera’s Adaptive Wireless™ software dynamically selects the optimum mix of receivers to maximize system performance, based on a large number of criteria and optimization constraints. Channel conditions are continuously monitored, together with other performance metrics, to determine the best receiver configuration. This enables a dynamic receiver architecture to deliver the highest performance HSPA.
