Static to Dynamic
switch from static to dynamic wireless communication has huge consequences.
Technical approaches created to solve technical problems turn out
to have major policy, business, and even social consequences.
These consequences, such as the possibility of replacing spectrum
licensing with “commons,” have generated a great deal
They would not be possible without the technical advances we have
described so far.
first and biggest consequence of the radio revolution is that licensing
of spectrum frequencies is no longer required.
Recall that the original basis for spectrum licensing by the government
was the fear of ruinous and pervasive interference.
If devices can operate with sufficiently low power and high intelligence
to avoid one another, exclusive rights are no longer necessary to
With a properly defined environment, users effectively can’t
prevent each other from communicating.
That opens the door for a new regime that allows anyone to transmit
within general technical guidelines.
there is enough capacity to support a commons,exclusive rights are
unnecessary. By analogy, the ocean is not infinite in size, but
it is large enough that ships can be trusted to navigate around
The ships, like dynamic wireless devices, can intelligently alter
their routes to avoid collisions. There is no need to give companies
exclusive shipping lanes, and prohibit other ships from using those
routes unless they pay a toll.
is making the wireless world look more and more like the ocean.
second implication of dynamic wireless systems is that the business
structure of markets changes. Static systems necessitate exclusivity.
The downside of exclusivity is that no one else can contribute to
a network. The licensee must bear the total cost of building network
The licensee typically recovers that cost by charging.
are, however, serious downsides. Deployment is slow because it is
costly and requires proven models for recouping that cost. Innovation
is constrained because only a few licensees control access to the
Uniformity and interoperability are enforced by the licensee, but
services and equipment are costly because they are provided in limited
volumes and based on proprietary standards.
wireless devices become more intelligent and commons arrangements
become viable, new market structures become possible.
those devices run on standards defined by industry bodies rather
than mandated by spectrum licensees, there can be open, competitive
markets to build better and more cost-effective equipment.
We move, therefore, from a market for centralized infrastructure
and proprietary services, to a market for consumer devices, software,
and ancillary services.
pay a significant fraction of the total network build-out costs
directly, by purchasing hardware, greatly reducing the expenses
service providers must undertake.
For many services, there are still core network costs—for
access points, backhaul to wired Internet backbones, authentication,
roaming, and security—but these are limited compared to the
allencompassing network build-out that licensed operators must undertake.
“Change the technology,and the economics the law of spectrum
must change, too.”
dynamic wireless devices allow for markets with greater diversity
at several points. Many equipment vendors, several providers, and
application or content providers can compete, because there is no
mandatory control point and each provider can leverage the infrastructure
built by others.
or dynamic spectrum management techniques may be used in any regulatory
environment. However, the nature of spectrum regulation heavily
influences incentives for deployment of intelligent devices.
The traditional, and still dominant, environment is exclusive licenses
for frequency bands.
Spectrum licensees have incentives to squeeze as much capacity as
possible out of their spectrum.
On the other hand, they have incentives to make the devices users
must purchase as inexpensive as possible.
In a static system, the money is all in the service; the devices
are dumb. There is no need to make them robust against interference,
because interference from other systems is prohibited and policed
by the FCC.
there is no great incentive to make the devices flexible, because
the service provider is focused only on supporting its own service.
Indeed, to keep the cost of switching to another service provider
high, licensed providers have an incentive to discourage software-defined
radios, which could switch frequencies (and hence service providers)
at the click of a mouse.
that changes in a commons environment.
Because wireless devices in a commons have no legally guaranteed
protection against interference, they must guard against it using
that is what dynamic wireless devices are good at.
Static systems create incentives to make the receivers as dumb as
means cheaper, after all.
Because the central transmitter does the heavy lifting, there are
no significant benefits from intelligence at the edge devices.
When end-user devices become dynamic, however, they contribute to
the integrity and performance of the overall system.
them smarter and more robust improves performance.
And without license restrictions keeping other devices from transmitting
on the same frequencies, robustness based on intelligence is the
only path open.
need to think of ways to bring [WiFi]
applications to the developing world so as to
make use of unlicensed radio spectrum to
deliver cheap and fast Internet access.”
UN SECRETARY GENERAL KOFI ANNAN
is the most prominent unlicensed wireless technology available today.
It is a family of spread spectrum wireless local area networking
standards designed to allow users to send and receive data at 11-to-54
Mbps within a few hundred feet of another WiFi device or access
WiFi is a great case study for the impact of dynamic wireless technologies.
data networking services have been What made WiFi such a success,
especially compared to previous wireless data systems.
After all, WiFi provides only short-range connections; on its own,
one access point can’t provide ubiquitous coverage in a neighborhood
WiFi has thrived because it has benefited from an ecosystem that
could only exist with the type of technology it uses.
Because WiFi is a low-power, spread-spectrum technology, WiFi devices
can coexist without the requirement of spectrum licensing to prevent
That means there is no need for service providers, cell towers,
controlled hardware markets, or expensive spectrum licenses.
Anyone can buy a WiFi device and establish a network.
WiFi is an open standard and an equipment-centered rather than service-centered
market (again, both of which flow from the nature of the technology),
costs are subject to computer industry downward pressure.
connectivity to homes is a topic of great consternation in the communications
Telephone companies are deploying DSL and cable TV operators are
deploying cable modem systems.
However, many millions still have neither available to them, and
a greater number have only one option.
Prices of these broadband services, approximately $50/month, are
high compared to the rest of the world.
services are generally asymmetric,providing far more bandwidth down
to the user than up from the user to the Internet. Combined with
terms of service restrictions, this architecture limits users from
running home servers and other actions. For business users, who
typically need higher bandwidth than homes, the only viable option
is often a traditional T-1 line at $1,000 per month or more.
There is thus great interest in alternatives.
WiFi or its variants, 802.11a and 802.11g,cannot simply be put into
service for last-mile deployments.
WiFi is a short-range technology designed primarily for connections
to a nearby hotspot.
Even if every home in a neighborhood had a WiFi access point, few
of those nodes would see one another.
can, however, envision scenarios for unlicensed wireless last-mile
connectivity based on technology that is in the market or likely
to be soon.
businesses or residences wanting more bandwidth, an 802.16 wireless
MAN technology could be used to deliver tens of megabits per second
over many miles.
This same technology, or a variant, could be used to reduce the
costs of backhaul, replacing costly wired connections.
end-user would buy a device, whether a dedicated piece of wireless
hardware, a broadband “residential gateway,” or a piece
of general-purpose hardware such as a laptop. The device could be
designed to operate with a particular unlicensed wireless network,
it might be deployed by a service provider, or it might have “discovery”
capability to automatically locate and connect with nearby access
points or wireless end-users.
is typically assumed today that last-mile broadband networks are
designed to provide access to the Internet .
Certainly, any broadband customer will want to access Internet-based
services available through the World Wide Web.
phone networks today are self-contained entities.
In the U.S., for example, there are six competing national networks.
Each has its own network of transmission towers.
If you are within range of five of those towers, but not the one
for your service provider, you won’t get service.
Things are a little better in Europe, where universal adoption of
the GSM standard allows for more roaming agreements between carriers,
but each carrier still must maintain its own complete network.
mobile phones evolve into SDR devices, the structure of the business
may change. Carriers will be able to share infrastructure much more
widely, because their subscribers will be able to transparently
access transmissions from whatever.
Globally, Act Locally:
should recognize and embrace the tremendous potential of the radio
radio signals do not respect political boundaries, spectrum policy
is inherently international.
Equipment vendors can better justify the investment needed to develop
new products when they can foresee a global market.
a general matter, the federal government should recognize that the
objective of spectrum policy is not to minimize interference, but
to maximize usable capacity.
It should move away from command-and-control toward more flexible
approaches, recognizing that there is value in a diversity of legal
In experimenting with exclusive property rights and secondary markets,
it should balance the potential gains against the opportunity cost.
spectrum has long been highly regulated and controlled by a small
group of licensees, opportunities for experimentation have been
WiFi happened almost by accident, because the 2.4 GHz “junk
band” spectrum was so congested with devices such as microwave
ovens that it was considered unusable for licensed systems.
the band was unlicensed and open to public access, engineers and
companies interested in wireless local area networking could use
it for their commercially and technically unproven technologies.
The government should ensure that its rules for unlicensed bands
allow for the broadest possible experimentation.
It should also ensure that it provides ample opportunities for experimental
authorizations that go beyond the existing rules, so that innovators
can develop novel techniques.
block of high frequency spectrum (above 50 GHz) that is currently
unassigned could be designated as an open space for completely unregulated
my own vision of Wireless quality:
VoIP transmission makes your voice so sharp that you can say "
Dog" in Europe and it "bytes" somebody in China.