3G: Wifi’s New Clothes

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/80211

Reprinted from australia.internet.com.

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