SCIENCE & TECHNOLOGY

Wireless broadband 

Shan't!

Jan 6th 2005 
>From The Economist print edition


Computer chips for "open-spectrum" devices are a closed book


TELECOMMUNICATIONS used to be a closed game, from the copper and fibre that
carried the messages, to the phones themselves. Now, openness reigns in the
world of wires. Networks must interconnect with those of competitors, and
users can plug in their own devices as they will. One result of this
openness has been a lot of innovation.

Openness is coming to the wireless world, too. Cheap and powerful devices
that use unlicensed and lightly regulated parts of the radio spectrum are
proliferating. But there is a problem. Though the spectrum is open, the
microprocessor chips that drive the devices which use it are not. The
interface information-the technical data needed to write software that would
allow those chips to be used in novel ways-is normally kept secret by
manufacturers. The result could be a lot less innovation in the open
wireless world than in the open wired one.

Take, for example, the Champaign-Urbana Community Wireless Network (CUWiN),
in Illinois. This group is trying to create a so-called meshed Wi-Fi
network. Wi-Fi is a wireless technology that allows broadband internet
communication over a range of about 50 metres. That range could, however, be
extended if the devices in an area were configured to act as "platforms"
that both receive and transmit signals. Messages would then hop from one
platform to another until they got to their destination. That would allow
such things as neighbourhood mobile-phone companies and a plethora of radio
and TV stations, and all for almost no cost. But to make such goodies work,
CUWiN needs to tweak the underlying capabilities of Wi-Fi chips in special
ways. 

When its engineers requested the interface information from the firms that
furnish the chips, however, they were often rebuffed. A few companies with
low-end, older technology supplied it. But Broadcom and Atheros, the two
producers of the sophisticated chips that CUWiN needs if its system is to
sing properly, refused. Nor is CUWiN alone in its enforced ignorance.
SeattleWireless and NYCwireless, among other groups, have similar ideas, but
are similarly stymied. Christian Sandvig of the University of Illinois at
Urbana-Champaign, who has been studying the brouhaha, believes regulators
ought to enforce more openness.

Broadcom and Atheros say that making the interface information public would
be illegal, because it could allow users to change the parameters of a chip
in ways that violate the rules for using unlicensed spectrum (for example,
by increasing its power or changing its operating frequency). That is a
worry, but it depends on rather a conservative interpretation of the law.
The current rules apply to so-called "software-defined radios" (where the
ability to send and receive signals is modifiable on the chip), and do not
apply directly to Wi-Fi. Also, by supplying the data, manufacturers would
not be held liable if a user chose to tweak the chip in unlawful ways. And
in any case, if the firms are really worried, they could release most of the
interface, keeping back those features that are legally sensitive. 

Nor is the interface information commercially sensitive. Engineers are not
asking for the computer code that drives the interfaces, merely for the
means to talk to them. And having the interface information in the public
domain should eventually result in more chips being sold. So it is hard to
see what the problem is beyond a dog-in-the-mangerish desire not to give
anything away. Time to open it up, boys.





 

 
Copyright C 2005 The Economist Newspaper and The Economist Group. All rights
reserved.


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