DoCoMo Cranks Up 3G
HSDPA is a packet-based data service evolved from -- and backwards compatible with -- earlier wideband-CDMA (W-CDMA) air interface standards, which offer maximum [ed. translation: only possible in the lab] data transfer rates of 2 Mbit/s. The technology uses adaptive modulation and coding (AMC) and other interference cancelling techniques to maximize the amount of data that can be transmitted over the W-CDMA downlink.
AMC schemes try to deal with interference and capacity problems on wireless networks by prioritizing which data should be sent first over a crowded downlink channel. HSDPA upgrades are supposed to better enable multimedia services like streaming video for wireless phones.
Used with existing W-CDMA networks, HSDPA-compliant handsets and base stations could increase wireless data transfer rates to a maximum of 10 Mbit/s, up to five times higher than is possible in 3G networks today -- at least in theory. HSDPA is a standardized feature in the 3rd Generation Partnership Project (3GPP)'s Release 5 specification, introduced in August 2002.
As part of the trial, DoCoMo will be using testing equipment from British company UbiNetics Ltd. (see UbiNetics Cranks Up DoCoMo 3G). According to the testing firm’s senior VP for strategy and product management, Stirling Essex, the network is still in its nascent stages, and it will be “a few years” before the operator announces an official launch. “DoCoMo will have to make changes to both the infrastructure and will also need phones that support HSDPA,” he explains.
Essex is unable to reveal the exact rollout date that DoCoMo is aiming for, commenting that it will depend heavily on the success of its current 3G network. “If its W-CDMA network really takes off and they run into capacity problems, then I expect them to bring HSDPA in earlier. They have the ability to accelerate it if they need to.” He also adds that DoCoMo’s decision to push HSDPA technology over W-CDMA is a direct result of archrival KDDI Corp.’s success in Japan with CDMA2000 technology.
In fact, an additional benefit of HSDPA to DoCoMo is its compatability with CDMA2000 1xEV-DV (Evolution Data Voice) technology, which is a couple of steps down the CDMA2000 upgrade path that KDDI is on. In theory, HSDPA could enable interoperability between the currently incompatible W-CDMA and 1xEV-DV. According to Unstrung research analyst Gabriel Brown, harmonization could occur in the 2006-2007 timeframe.
Essex claims that UbiNetics has received significant interest in HSDPA since the beginning of 2003. “It has really taken off in the last four to six months,” he says. “It was interesting to see how many people were talking about it at the 3GSM World Congress, and yet last year it wasn’t even mentioned. A lot of that is down to DoCoMo’s influence.”
Just how great an impact HSDPA will have on the 3G market is open to debate. The majority of operators worldwide have scaled back rollout of next-gen technology, due to financial constraints and concern over market demand for new multimedia services. Many service providers have also pushed wireless LAN services in a concerted effort to boost awareness of data offerings (see France Tele Hits Hotel Hotspots and Swisscom Buys a Bevy of PWLAN).
“If you look at wireless networks today, applications for these high data rates have still not been identified,” warns Jorgen Lantto, founder of telecom consultancy Northstream. “It remains to be seen what application will require data rates of 10 Mbit/s. I am sure W-CDMA operators in Europe and elsewhere will eventually deploy this technology, but it is too early to tell exactly when. It will take at least three to four years.”
Infrastructure vendors have also expressed their intention to supply hardware to the HSDPA market. At CTIA Wireless 2003, Nokia Corp. (NYSE: NOK) demonstrated an HSDPA product that claims to double base station capacity at the air interface, while Lucent Technologies Inc. (NYSE: LU) has launched what it believes is the world's first turbo decoder chip for wireless data terminals that support the HSDPA standard (see Nokia Shows Enhanced 3G and Bell Labs Chip Blazes).
Lucent says the chip is fast enough not only to support first-generation HSDPA systems, but also future Multiple-Input/Multiple-Output (MIMO) HSDPA systems, which could achieve peak data rates up to 20 Mbit/s. MIMO systems, which use multiple antennas to achieve the increase in data transfer rates, are expected to be ratified in 3GPPP’s Release 6 specifications, due out later this year.
— Justin Springham, Senior Editor, Europe, Unstrung