- Posted
- Nov 1, 2005
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Life in the fast lane is only going to get faster
When mobile network vendors first began talking up third-generation services in the late 1990s, they likened them to having a broadband connection in your pocket. There was talk of 2 megabit-per-second data speeds, high-quality two-way video calls and streaming television broadcasts.
However, in the cold light of 2005, reality is somewhat different. While there are a growing number of 3G networks now up and running, most offer data performance nowhere near those early promises. Users report typical data speeds hover around the 200 Kbps mark. Such speeds are fine for limited data activities but fall far short of what's required for more bandwidth-intensive mobile activities. Video is possible but tends to be jerky and unreliable. Downloading large files can still require considerable patience.
While the technology underpinning most 3G networks - wideband CDMA - is capable of higher speeds, carriers have opted to configure their networks for enhanced capacity, albeit at these slower rates.
However, an emerging technology promises to give them the best of both worlds. Called HSDPA, it is capable of delivering download speeds as high as 14.4 Mbps. At the same time, its improved utilisation of scarce radiofrequency resources means more concurrent users can be crammed onto the network.
Although no carriers are likely to offer this peak performance in their networks, advocates believe initial data rates of around 1.8 Mbps will be widely available. Some test networks on show at recent industry conventions have already been displaying speeds of more than 3 Mbps.
The increased download speeds (HSDPA has no effect on upload speeds) will allow a significantly improved end-user service. For example, downloading a typical MP3 music file would take around two minutes over a traditional second-generation mobile connection. The same file would take 20 seconds over a 3G connection and just four seconds when using an HSDPA service. By comparison, a 10-minute video clip that took seven minutes to download over a 3G connection would take just 90 seconds over HSDPA.
Nortel's director of wireless for Australia and New Zealand, Rob Inshaw, says HSDPA is essentially a more efficient way of delivering data over a wireless network. "The 3G community realised early on that, by the time the initial 3G networks made it to market, people were already saying that data speeds like 384 Kbps didn't quite cut it," he says. "The true experience promised by 3G just wasn't quite there, and the development of HSDPA has been a response to that."
In much the same way that EDGE technology improved the spectral efficiency of GSM-based GPRS networks, HSDPA does the same thing for WCDMA-based 3G networks. As well as higher data speeds, the technology is attractive to carriers because it allows a given network to support a larger number of users. This is important when carriers are trying to extract as much payback as possible from their investments in radio spectrum. According to industry tests, HSDPA provides three times the network capacity of WCDMA. It also offers much reduced network latency, which is important when conducting data sessions.
Nokia's vice president of mobile solutions, Bob Brace, says HSDPA is an important step in the process of narrowing the gap between the fixed and mobile data worlds. "People are coming to expect the sort of performance from their mobile devices as they get from their desk-bound PC," he says. "HSDPA is the next step in making this a reality."
While acknowledging that the first 3G networks suffered a bit from over expectation when it came to data rates, he says Nokia has been investing considerable amounts of money to further develop mobile air interface technologies. "At the end of the day, people don't care what the technology is that makes it work - they just want fast speeds and to be able to use the applications they need for their daily activities," he says.
The improved performance offered by HSDPA is being eagerly evaluated by mobile carriers around the world. Ericsson Australia solutions manager, Garry Harsley says it represents a strong opportunity for network operators to increase the revenues they are earning from mobile data services.
"There are some new business models that can be created around this," he says. "Carriers will open up a whole broadband data market that they don't have access to today."
Harsley predicts carriers may go to the extent of offering subsidised laptop computers to customers who sign up for an HSDPA data service.
"A high-end smart phone can cost $1000 and some laptops are at a similar price point, so subsidising them in the same way is not out of the question," he says. "We could see a complete change in mindset when it comes to high-speed mobile data."
Vendors and carriers attracted considerable criticism when the first generation of handsets and devices were launched for 3G networks a couple of years ago. Poor battery life and unreliable connections caused many users to shy away from the new technology. For that reason, vendors are determined to wait until devices suitable for HSDPA networks have been fully tested before releasing them to the market. Initially access is likely to be limited to laptop PC cards, before being extended to compatible mobile handsets.
Inshaw says terminal devices represent one of the biggest hurdles when it comes to rolling out new technologies such as HSDPA. "The chipset within the handset is the limiting factor," he says. "The first ones to appear will support 1.8 Mbps and, over time, other devices will come out supporting speeds up to 3.7 Mbps."
No Australian carriers have announced any plans to roll out HSDPA in this country yet, however industry watchers expect the first services to appear during 2006. One of the attractive features of HSDPA for carriers is the ease with which existing 3G networks can be upgraded. Inshaw says newer 3G base stations will only require a software upgrade. Older base stations can still be upgraded but may require the replacement of some circuit boards and changes to power amplifiers.
While data will travel over the HSDPA link, voice calls will still be made using the more traditional 3G technology. Inshaw says this has led to some carriers expressing concern over what the differences in the way the two technologies work might do. "3G is all about power control and power management," he says. "It's about getting the base station and the handset to talk to each other using the lowest possible power while maintaining call quality. This improves the capacity of the network."
HSDPA, on the other hand, bursts at maximum power to the user. Some carriers are concerned that this could result in lower capacities being possible in cells. To overcome the challenge, some have opted to deploy a dedicated carrier for HSDPA traffic on a different frequency from that used by voice calls. Inshaw points to European carriers Orange, Vodafone and O2 as some that have done this.
There has also been speculation from some within the telecommunications industry that HSDPA will also have to cope with competition from other emerging wireless technologies such as WiMax.
WiMax is a wireless networking technology that offers speeds as high as 70 Mbps over distances as far as 70 km. Its proponents position it as a last-mile technology that can overcome the limitations of copper wires and has the potential to provide broadband services in regional and remote areas.
Ericsson's Harsley says that, when talking about HSDPA, WiMax is a "complementary rather than competing" technology. "WiMax is good for providing DSL replacement services, but it does not have the robustness around mobility that you get from WCDMA networks," he says.
Harsley says mobile operators can still get value from WiMax, perhaps using it instead of microwave links to provide traffic backhaul services from base stations.
"You have to remember that no one technology is going to take over this space," he says. "There will always be a mix of technologies to provide the service and WiMax is likely to be in that mix."
Further down the track, WCDMA networks are expected to evolve even more, pushing data speeds even higher. The next buzz technology is HSUPA (high-speed upload packet access) which increases upload speeds from 3G devices to as high as 5.8 Mbps. As well as improving data speeds from the handset or laptop computer outward, the introduction of HSUPA (slated for around 2007) will also allow voice over internet protocol (VoIP) services to be conducted as such services require a symmetric data link. Even further down the 3G evolution track, vendors are starting to talk about a so-called fourth-generation mobile technology that could deliver blistering data speeds of up to 100 Mbps.
Such data speeds would make possible a range of applications that cannot even be contemplated today. Three-dimensional graphics, immersive virtual reality graphics and sound indistinguishable from the real thing may be possible. Meanwhile, while HSDPA and HSUPA hold the promise of significantly improved data speeds in the WCDMA 3G world, similar technologies are providing performance improvements in CDMA networks.
Nortel's Inshaw says technologies such as 1xRTT and EVDO are doing to CDMA networks what HSDPA is doing to WCDMA networks. "We see HSDPA as a response to what the CDMA group did with EVDO," he says. EVDO gives typical download speeds of more than 300 Kbps and a revision due to hit the market soon will increase this even more. From the user perspective, such technologies will ensure that mobile data rates continue to improve, following a gradual path. Rather than experiencing a dramatic lift in rates, most will simply be offered an improved suite of services and content packages by carriers, keen to lift their average revenue per user (ARPU) rates even higher.
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