Written by: Jan Derksen, Robert Jansen, Markku Maijala and Erik Westerberg
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Operators around the world are rapidly introducing high-speed downlink packet access (HSDPA) services into their WCDMA networks. On September 22, 2006, fifty-nine networks already offered commercial HSDPA services.
The authors present the results of HSDPA measurements made in live, commercial networks supplied by Ericsson. They also describe WCDMA hardware and software features from Ericsson that contribute to these excellent results. Finally, they describe future enhancements to HSDPA technology that will further improve performance.
HSDPA is making impressive inroads in the commercial service arena. On September 22, 2006, the Global mobile Suppliers Association (GSA) reported that 121 HSDPA networks had been planned, were being deployed, or had been launched. Moreover, 59 of these already offered commercial HSDPA services. Likewise, 58 HSDPA devices had been launched as of September 18, 2006.
Numerous operators thus do already, or will soon, offer mobile data services based on HSDPA. To target mobile as well as fixed usage, many operators have also introduced attractive pricing strategies with flat-rate tariffs. In some cases, HSDPA represents the first opportunity end users have had to access broadband services because fixed broadband access has not been available where they work or live.
The majority of HSDPA devices launched to date are category-12 devices – that is, they support a maximum of five HSDPA codes and QPSK modulation.4 The maximum speed (layer-1 peak rate) of category-12 devices over the air interface is 1.8Mbps. After making adjustments for radio-protocol overhead, the peak rate for layer-2 (MAC-hs) error-free transmission is 1.6Mbps. And because the HSDPA systems target a radio block error rate (BLER) of 10%, the available radio bandwidth to end users is 1.5Mbps. HSDPA devices that support 16QAM modulation have also recently been released. These category-6 devices have a maximum speed of 3.6Mbps over the air interface; end-user bandwidth is 3.1Mbps.
Measuring HSDPA performance
The measurements made using category-12 (QPSK only) terminals were conducted in Europe during the first half of 2006 in commercial WCDMA networks supplied by Ericsson. The measurements made using category-6 terminals were carried out in live networks in Asia in August 2006. In both cases, the results are comparable with predictions of previous theoretical analysis.