Orange demonstrates technique to use L-band spectrum
Carrier works with Qualcomm and Ericsson on first live trial of Supplemental Downlink to boost 3G capacity
Published: 26 February, 2013
Supplemental Downlink (SDL) is one of the techniques with which operators aim to make the most of fragmented spectrum holdings and formerly useless frequencies. A form of carrier aggregation, it allows TDD spectrum in bands like 700MHz (as tested by AT&T) and L-band to provide additional downlink capacity for an FDD LTE or 3G network in a different frequency.
AT&T and Qualcomm have been working on this technology to make use of the 700MHz unpaired frequencies the carrier bought from the chipmaker (which previously used the spectrum for its MediaFLO mobile TV service). Now Qualcomm is talking about trials with another early moving carrier, Orange, which have been conducted in the L-band (1452-1492MHz) with Ericsson.
The European Union's standards body, CEPT, green-lighted the use of this mobile satellite band for two-way mobile last year when it decided to harmonize the L-band and reserve it specifically for SDL. Orange was the first to act, obtaining trial licences in the French city of Toulouse from regulator Arcep in June 2012. The trial system combines this spectrum with Orange's 2.1GHz 3G frequencies, and uses base stations from Ericsson and Qualcomm device prototypes. The first public demonstration was shown off last week.
Orange says SDL represents a significant step forward from traditional spectrum aggregation systems already in use for HSPA+ and LTE.
"After two years of extensive studies, CEPT ECC decided to harmonise the L-band for supplemental downlink. I am happy to see the industry materializing rapidly this decision which will generate substantial benefits to European users," said Eric Fournier, chairman of the Electronic Communications Committee.