3G: Wifi's New Clothes
September 09, 2002
A New Zealand startup believes that 802.11 is a worthy 3G competitor.
RoamAD is a New Zealand (NZ) company pioneering an enhancement to the IEEE 802.11b wireless standard that enables metro-wide mobile broadband connectivity. The network uses proprietary propagation algorithms and multipoint-to-multipoint network architecture.
This allows RoamAD to deploy the service over hundreds of square kilometres with ubiquitous, non line-of-sight coverage. Rather than a fixed wireless, last mile alternative, the network is pitched as a compliment to 3G and provides roaming broadband of 330 kbps.
RoamAD says "the marginal cost of CPE and substantially lower network infrastructure costs result in an end-user price point that is competitive with conventional landline and cable broadband services, and dramatically below those of 2.5G and 3G mobile services."
During the initial stage, the company has deployed a three-square kilometre demonstration network with the Auckland CBD. A metro-wide, 100 square kilometre, rollout is to come.
"RoamAD had to overcome four major obstacles that have been the reason why, to-date, 802.11b has not been deployed to service areas beyond those commonly referred to as 'hotspots'," according to CEO, Paul Stoddart.
The first is security. "Traditionally 802.11b has relied on WEP," he says. "Much has been made in the IT&T arena about the WEP encryption protocol having been compromised. The emotive nature of security has been one of the key barriers to wholesale adoption of 802.11b."
RoamAD has developed their own security solution, a hybrid of proprietary network-edge security and industry standard data encryption. To access the network, an end-user must have a valid MAC address for their Wi-Fi device. Once access has been granted to the network, all data transmitted or received is encrypted based on IPSec.
The second major obstacle is backhaul. Stoddart says, "one of the flaws in the hotspot model is that the operator must lease a terrestrial circuit from an incumbent network operator to provide connectivity between the hotspot and their network operations centre. The cost of these circuits represents a significant fixed cost that must be borne until an operator achieves critical mass."
"Furthermore, " he says, "the hotspot operator is reliant on the incumbent network operator to not only install but also dimension these circuits in a timely and cost-effective manner in the future. RoamAD's engineers have developed a wireless backhaul solution thereby avoiding the need to lease terrestrial circuits from the incumbent telecom operators."
Coverage is the third major obstacle. "Traditionally, to receive coverage from an 802.11b access point an end-user must be within fifty metres and often within line-of-sight," according to Stoddart. "To an end-user this means that to gain access to a hotspot coverage area they are required to schedule a visit to a hotspot. This offers limited utility to an end-user by virtue of convenience. The RoamAD network solution has been designed to provide an end-user with ubiquitous coverage within the network area."
The final obstacle is congestion. Wireless access points have become a dime a dozen, competing with each other for space within the 2.4Ghz range. "The RoamAD network architecture is a star-grid topology," he says. "To the end-user this means that at any point within the network they are supported by a minimum of four different access points."
The star-grid topology provides segmented coverage from multiple areas, redundancy of overlapping signals, diversity within the system, and a multitude of connection options for the end user in the case of outage or when a point is loaded.
Several of the algorithms have been developed to enable RoamAD to deploy access points in traditionally noisy environments, according to Stoddart. The company has deployed 47 access points to provide coverage and backhaul within the demonstration network.
To access the network, 86% of the end users will require a standard 17 to 20 dB PCI, ISA, or PCMCIA card. A small number of end users within the network may require a 3dB antenna. Within the network, an end-user with a standard 802.11b PCMCIA card will enjoy coverage in 85% of the network area. With an additional antenna, 98% coverage is achieved.
"The fully-functional RoamAD demonstration network was deployed to enable RoamAD to show, rather than tell, people what is achievable," according to Stoddart. "The demonstration network area has been selected because it represents a cross-section of the environment that the full network will service, including public open spaces, high-rise buildings and older densely populated heritage sites."
A walk through of the coverage area with an 802.11b device, such as a PDA or laptop fitted with PCMCIA card, verifies that connection is possible from nearly everywhere. Connection is weak or unavailable in a few places. These include elevators, underground basements, or within electro magnetically 'caged' areas.
In another experiment, a BlueTooth headset device was operated in close proximity to a RoamAD access point. The BlueTooth device continued to function normally even while a large file download was taking place over the POP. The BlueTooth device did not noticeably affect the download.
Stoddart says the network was also deployed to underpin capital raising and reseller recruitment. "There are currently 52 non-commercial active users, albeit stakeholders as opposed to 'customers'."
RoamAD expects to launch commercially in Auckland before Christmas. They have received significant interest from overseas network operators and plan to deploy in Sydney and Melbourne next year.
* Hear how 3G networks have been used in tandem across Europe from a leading technology expert from Ericsson at our 802.11 conference on the 19-20 September. Hurry, only two weeks to go - registration and more at http://australia.internet.com/events/80211Reprinted from australia.internet.com.