Cellular vs Wi-Fi: One’s been around a while, the other’s a recently arrived upstart. One costs a lot to build, the other can be put up for next to nothing if you have a couple of laptops and the right network cards. One operates in licensed spectrum, the other in unlicensed 2.4GHz spectrum, the same type your microwave uses. Will one wireless technology drive out the other, or can they live together in perfect harmony?
Cellular networks and Wi-Fi, the wireless technology based on the 802.11 technical standard, are sometimes portrayed as competitors for wireless data users’ dollars.
However, some users and providers can see a future in which both are widely utilised — Wi-Fi for small LANs on commercial and educational campuses and possibly metropolitan areas, and cellular covering wider areas.
An ideal situation would see users able to switch from one to the other, depending on what works best wherever they are at any given moment.
New Zealand start-up RoamAD for one sees it that way and is seeking a telco reseller for its multipoint-to-multipoint Wi-Fi-based technology, to which it is envisaged cellular customers will switch over when they enter RoamAD-covered areas.
“We’re looking to cover metropolitan areas, not the countryside,” says RoamAD chief executive Paul Stoddart.
However, wireless specialist Luigi Cappel, of Auckland, doesn’t see the day coming when customers will roam seamlessly from their provider’s cellular network to the Wi-Fi network their provider is partnering with.
“Having mobile devices equipped for both cellular and Wi-Fi is logical, but manually switching is more likely.”
Attempting automatic switching could be “like when you’ve got a back-up server that automatically takes over, instead of a mirror server and they end up chatting and nothing works”.
The most common deployment of Wi-Fi is in corporate and educational wireless LANs. But the model of a chain of LANs built by a provider, with users paying for the service, is up and running in Wellington with CafeNet, a chain of access points — “hotspots” — around the capital’s CBD. That project, however, is in its early stages, having recently finished beta testing. It has attracted few users.
Users of private, in-house Wi-Fi LANs include Fonterra, Hallensteins, Toshiba, Microsoft and St Kentigern’s College in Auckland.
For many, cellular serves their needs better; for example, petfood manufacturer Masterpet last year began using Telecom’s CDMA1x MobileJetStream for field reps who visit supermarkets. IT manager Monib Moayyed says that for wireless functions not covered by Mobile JetStream a basic radio wave technology is used. As for Wi-Fi: “I’m sure we’ll look at it, but at this stage there are no plans to use it,” he says.
While there is no real competition between Wi-Fi and the mainstream cellular data services offered by Telecom and Vodafone, for some, Wi-Fi is an alternative to wire-line communications.
In Invercargill, ISP Southnet is running Wi-Fi services in Invercargill, Queenstown and Te Anau.
Medlab Southland was one of the first to sign up, after trialling the service last year. Systems manager Graeme McLaren says after a few teething troubles, it’s working well. “We’re very happy with it.”
The service is mainly used to answer queries from GP practices that can be answered quickly and efficiently by Medlab staff. They often need to look on the internet for the information. Previously, that was attempted using dial-up, but the slowness meant hold-ups. The Wi-Fi service was selected because it compared favourably with Telecom’s DSL-based terrestrial JetStream on price and performance, he says. SouthNet runs on an ISP model and the reach of the standard Wi-Fi wireless LAN — about 300m — is boosted by the use of directional antennas and air bridges, to give a “daisy chain” effect allowing coverage to many kilometres.
The daisy chain model is also being used by ISPs in other countries to provide broadband to areas where DSL cables don’t reach.
A different approach
RoamAD has added a twist to the Wi-Fi concept, engineering its experimental network in central Auckland so that points of presence overlap, providing carry-over Stoddart claims is faster than between GPRS cells.
In building a cellularised version of Wi-Fi, RoamAD has sacrificed the speed that is one of the selling points of conventional, standalone Wi-Fi wireless LANs: the network operates at 330kbit/s, faster than New Zealand’s Vodafone GPRS and Telecom MobileJetStream cellular networks, but much slower than the maximum 6Mbit/s to 7Mbit/s in the field and 11Mbit/s under ideal conditions that conventional Wi-Fi delivers.
Stoddart says the interference that Wi-Fi is notorious for has been addressed by SMT (site management tool), proprietary software which seamlessly hands users over to a different channel if another signal is encountered.
He says the network has been engineered “in anticipation of a rising noise floor”, meaning it can cope with increasing levels of interference.
SMT also handles quality of service by controlling packet re-tries, a common source of congestion in wireless networks, and the network’s security.
Overseas, there are also signs of Wi-Fi and cellular working together. In May, Californian wireless infrastructure service provider Green Packet launched SONaccess, an IP-based product that allows seamless roaming between cellular and Wi-Fi networks.
Another US provider, Padcom, has a similar technology that goes even further, integrating IP and non-IP networks. Also in the US, there are grand plans to build nationwide networks of wireless LAN hotspots — Intel, IBM and AT&T have teamed up to form Cometa Networks, which plans to have 20,000 access points across the country by 2004 and another provider, T-Mobile, has already built 2000 and has another 3000 planned by the end of this year.
Such pervasive networks mean travelling consumers and commercial “road warriors” would be able to find somewhere to plug in, whether it be in Washington DC or Washington state. Others are planning special, extended Wi-Fi LANs at truck stops across the nation and FedEx network services director Jeff Amerine told Computerworld’s US counterpart that pervasive Wi-Fi LANs open up the prospect of being able to transmit bandwidth-intensive items such as freight bills via Wi-Fi, rather than cellular GPRS.
Cappel says the many hotspots model doesn’t impress him as much as the RoamAD model.
“I’m not excited by hotspot technology, going to a cafe with a wireless LAN. In the US, for example, you have six or so operators offering the same sort of service — you can go to a hotel, get on to the network and it can be added to your bill. At a different hotel, you may not be a subscriber to the service it uses and you’ll need a card to temporarily subscribe.”
Being able to go to a cafe and log on is great, he says, but only if you want to go to that particular place. “The concept of moving it anywhere within the area you work is what excites me.”
Private Wi-Fi LANs are simply wired LANs without the wires, Cappel says and many would add “without the security either” to that statement. It is in the application of Wi-Fi to building ubiquitous multipoint-to-multipoint networks that the threat to telcos emerges, he says.
“Wi-Fi has the potential to be highly competitive for a short period. At the moment, the technology isn’t owned by the telcos.
“If I was a telco, firstly I’d say ‘this is a threat’, and second, ‘how do we do a joint venture with them?’”
The fact that Wi-Fi allows mobile VoIP as well as mobile data increases the threat to telcos, he says. “Some organisations are using Wi-Fi within their own networks for VoIP.”
Cappel sees telcos and ubiquitous Wi-Fi providers ultimately partnering, the Wi-Fi company providing the network and the telco the infrastructure for billing and handling volume traffic.
RoamAD, for its part, is yet to strike a deal with a telco reseller, despite plans to build another network in Wellington. This suggests that in the immediate future it is likely to remain a case of either cellular or Wi-Fi, depending on your needs, with Telecom and Vodafone slugging it out in the cellular market and many providers selling hardware and services in the Wi-Fi space.
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