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HSPA+ Advanced: Multi Carrier

Qualcomm’s HSPA+ R&D program was the first in the industry to demonstrate a Multi Carrier (MC) HSPA system at MWC 2008. MC-HSPA provides wireless bandwidth aggregation by combining multiple 5MHz HSPA carriers from the same sector to offer a higher data rate pipe to the user which ultimately increases overall capacity. In addition, MC-HSPA leverages the existing operator network resources making it possible for mobile operators to offer customers a much higher quality broadband experience.

Mobile data and applications requiring greater bandwidth are now more prevalent. MC-HSPA provides operators the means to offer higher data rates to all users in the cell, thus enhancing mobile broadband experience. It also significantly increases the number of users that can be supported per carrier for a given user experience.

Multi Carrier can be supported in a number of scenarios, depending on the number of available carriers, the direction of the carriers (i.e. uplink or downlink), the residing bands of the carriers, and whether the same-band carriers are adjacent to each other. 3GPP first introduced MC-HSPA in R8, and has been expanding its capability in subsequently releases to provide further improvements. Some of the Multi Carrier scenarios supported by 3GPP today are:


  • DC-HSDPA is a 3GPP R8 feature that enables the aggregation of two adjacent downlink carriers in the same sector. There are more than 124 commercial DC-HSDPA networks in 136 countries today.


  • DC-HSUPA is a 3GPP R9 feature that enables the aggregation of two adjacent uplink carriers in the same sector.

Dual Band Dual Cell HSDPA (DB-DC HSDPA):

  • To enable MC-HSPA for operators who do not have two adjacent carriers, 3GPP defined DB-DC HSDPA in R9. It enables aggregation of two downlink carriers across two bands in the same sector, with uplink transmission on only one of the two bands. 3GPP R9 supports three band combinations, and additional combinations were defined in later releases.

Four-Carrier HSDPA (4C-HSDPA):

  • 4C-HSDPA was initially standardized in 3GPP R10 to enable the aggregation of three or four downlink carriers from one or two bands in the same sector. Multiple configurations specifying the number of aggregated carriers and band combinations were defined in 3GPP R10 and R11.
  • 3GPP R11 further enhanced 4C-HSDPA to enable the aggregation of non-contiguous downlink carriers from the same band in a sector. Up to four carriers from two non-contiguous blocks can be aggregated to form a form a larger data pipe.

Eight-Carrier HSDPA (8C-HSDPA)

  • 3GPP R11 further enhanced MC-HSPA to support the aggregation of up to eight downlink carriers in the same sector.

Supplemental Downlink is a special case of MC-HSPA which aggregates paired downlink carriers with unpaired downlink carriers in another band. HSPA+ Advanced (beyond R10) takes MC-HSPA to the next level through Multiflow which aggregates carriers from different sectors on either the same or different NodeBs.

Multiple field trials for DB-DC HSDPA, 3C-HSDPA and DC-HSUPA are underway or completed with major infrastructure vendors. Further information on HSPA+ Multi Carrier can be found in the videos and white papers on this page.