Qualcomm Innovation

HSPA+

The HSPA+ program is focused on research into technologies that improve the performance of UMTS, a widely deployed 3G standard specified by 3GPP. UMTS is currently deployed by approximately 310 wireless operators and is used by nearly 500 million subscribers (Jan ‘10). The evolution of UMTS by the addition of High Speed Packet Access (HSPA) in Release 5/6 of the standard has, for the first time, allowed UMTS operators to offer high speed wireless broadband services. HSPA has been widely successful and has led to a tremendous increase in data traffic over the wireless networks. The HSPA+ program aims to further improve performance of both voice and data services over UMTS.

The HSPA+ team was first to demonstrate that high quality Voice over HSPA is feasible (in MWC 2007) and can provide up to three times the existing circuit switched voice capacity. Voice over HSPA also frees up significant data capacity in the network. The HSPA+ program also demonstrated robust mobility improvements that ensure high quality Voice over HSPA and reduced interruption time for data services when a user moves across cells in the network.

The HSPA+ program was the first in the industry to demonstrate a Multi Carrier (MC) HSPA system (in MWC 2008). MC-HSPA combines multiple 5MHz WCDMA carriers to offer a wider bandwidth higher data rate pipe to the user and increases the overall cell capacity. MC-HSPA leverages the existing operator network resources and enables operators to offer a much higher quality mobile broadband experience to its users. In Release 9, HSPA+ Multi-Carrier was further enhanced to include MIMO operation, inter-band carrier aggregation and UL carrier aggregation. After helping to introduce support in the standard for Multi Carrier in Release 8 and 9, the HSPA+ team is now focused on enhancing multi-carrier in Release 10 by combining more than two downlink carriers within or across spectrum bands to enable a 20MHz HSPA+ system deployment. Wider bandwidth MC-HSPA across bands will allow operators to further leverage all their network and spectrum resources to offer a better mobile broadband service to their subscribers.

In addition to working with the 3GPP standard bodies to improve UMTS performance, the HSPA+ program is focused on standards independent techniques like UE and Node B receiver enhancements that can greatly improve performance. Some of the notable ones are the work on UL interference cancellation and transmit diversity techniques. UL interference cancellation, a technique implemented on the Node B, can provide up to 75% increase in UL data capacity using the same network resources and without a need to change the existing handset base. The HSPA+ program has partnered with leading infrastructure providers to increase industry awareness and commercialize UL interference cancellation. The HSPA+ program is also the first to demonstrate benefits of UL Beamforming (Closed Loop Transmit Diversity) in HSPA+ to increase cell-edge data rates and/or increase coverage (MWC 2010).

Given the large installed UMTS base, the HSPA+ program is focused on incremental techniques that greatly improve performance and help operators maximize their return on investment in UMTS.