Multicarrier HSPA

Multicarrier HSPA

Posted by Sam Churchill on January 17th, 2011

What is multicarrier HSPA? Qualcomm (video) and Ericsson (pdf) explain that it enables two carriers to be bound together, for twice the bandwidth.

Current commercial network deployments, such as AT&T’s HSPA+, are based on 3GPP Release 7, which can support a maximum speed of 28Mbps in the downlink if 64 QAM modulation and MIMO antennas are used. Without MIMO, 64 QAM modulation is used in T-Mobile’s current HSPA+ network. The slower HSPA+ 14.4 system uses 16 QAM and is the system AT&T is currently using. Both systems can go faster with MIMO antennas.

T-Mobile claims their new HSPA+ upgrades will push the theoretical limit up to 42Mbps.

Qualcomm explains that peak data rates of 42Mbps, twice the normal HSPA+ data rates, can also be enabled by using two 5MHz HSPA+ channels. In Release 8 of the 3GPP standard, it is possible to increase data rates reach up to 42Mbps using either a combination of MIMO and 64QAM (which is what T-Mobile USA has announced in the United States), or by using two 5MHz carriers with 64QAM.

Not all mobile operators have access to more than 5 or 10 MHz of spectrum in a single operating band.

Dual-Band HSDPA can enable operators to aggregate multiple 5 MHz spectrum blocks from two different bands; for example, combining 5 MHz blocks from the PCS (1900 MHz) and AWS (1.7/2.1 GHz) bands for operation of a Multi-Carrier HSDPA system.

The Dual-Carrier feature in 3GPP Release 8 applies only to adjacent carriers within the same band. HSPA+ Rel. 9 and Rel.10 further expand the multicarrier support, with aggregation across different spectrum bands and uplink multicarrier.

3GPP Release 9 focuses on the support of features that further increase bit rates to 100Mbps using three to four 5MHz blocks of downlink spectrum. The 2.6 GHz spectrum has been identified globally by the ITU as the ‘3G extension band’, for next-generation networks such as LTE (pdf).