Open spectrum

04/10/23 Copyright 2003 Robert J. Berger & GLOCOM 1

Open Spectrum

New Technology / FCC SPTF Impact and Policy Implications

Robert J. BergerGlocom Visiting Research Fellow

[email protected]


Introduction The FCC formed a Spectrum Policy Task

Force (SPTF) in June 2002 to identify and evaluate changes in spectrum policy that will increase the public benefits derived from the use of radio spectrum.

This was the first time that there was a comprehensive and systematic review of FCC spectrum policy.


FCC Interest in Spectrum Policy Reform


Interest in new spectrum access models FCC has not kept up with the pace of

communication tech and accelerating demand for spectrum

Current “Command + Control” policy and procedures micromanage spectrum Thus it is outmoded and obsolete

Need “out-of-the-box” ways to allocate and maximize spectrum access Find ways to maximize public benefits delivered

through spectrum based services and devices


Drivers for Spectrum Policy Reform Explosive Demand for Spectrum-Based

Services and Devices Technological Advances: Enabling

Changes in Spectrum Policy Increased Access: Mitigating Scarcity of

Spectrum Resources


Explosive Demand for Spectrum-Based Services and Devices Consistently underestimated demand

1994 projected 54M mobile phone users for 2000 Actual number of users in 2000 was 110M

Unlicensed band (2.4Ghz) spurred explosion of new devices and services $2.9B IN 2002

New tech allows for devices paid for & controlled by millions of end users Old policies based on small number of licensees

(broadcasters)


Tech Advances: Enabling Changes in Spectrum Policy Digital Signal Processing allows for radical

new modulation techniques Wideband Spread Spectrum Ultra-Wideband pulse Very low power per hertz

Cognitive / Software Defined Radios Dynamically and Intelligently utilize and share

spectrum Moore’s Law makes it practical and affordable

(and inevitable)


Increased Access: Mitigating Scarcity of Spectrum Resources Measurements of actual spectrum utilization in

Metro areas showed: Nearly 100% of spectrum allocated, but only 30%

actually used Looking for new ways to better utilize spectrum

Underlay Spectrum Commons (UWB, Spread Spectrum)

Cognitive Radios dynamically sensing and releasing spectrum

Secondary Markets


New Technologies

Radically new way to utilize & expand the capacity of spectrum


Some Spectrum Basics

image obtained from http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html


Time vs. Frequency Time Domain

Wavelength or Pulse Width duration

Viewed with Oscilloscope

Frequency Domain Cycles / Second Viewed with

Spectrum Analyzer (Spectrograph)

Time Frequency


New tech facilitates sharing beyond 802.11Wireless LAN

Underlay legacy spectrum users Wideband Spread Spectrum Ultra-wideband nano-pulses Pico-watts / Hertz

Intelligently utilize unused local spectrum Cognitive / Software Defined Radios


Wideband Spread Spectrum Trades off Spectrum

for power Wider spectrum

produces more sharing and bandwidth

Called Process Gain Can underlay legacy

narrowband users

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

Graphics from Spread spectrum communications by Jay Fitzsummons, Troy Morris and Tony Parezanovic http://murray.newcastle.edu.au/users/staff/eemf/ELEC351/SProjects/Morris/project.htm


Direct Sequence Spread Spectrum Pseudo-noise (PN-

code) mixed with Data to produce the coded signal to modulate a carrier

Looks like noise source centered around the carrier with a bandwidth of the Pseudo-noise

Receiver knows PN-code to demodulate signal

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

Graphics from Spread spectrum communications by Jay Fitzsummons, Troy Morris and Tony Parezanovic


Frequency Hopping Spread Spectrum Data is conventionally

modulated on carrier SS Bandwidth is carved up

to many narrow channels PN-code selects which

channel is utilized as the carrier

Hopping rate is in order of milliseconds / hop thus minimizing interference with legacy narrowband users

Graphics from Spread spectrum communications by Jay Fitzsummons, Troy Morris and Tony Parezanovic


Ultra-wideband nano-pulses Extremely short pulses

instead of carrier waves 10 - 1000 of picoseconds

(trillionths of a second) wide in time

1 - 10 Gigahertz wide in frequency

Picowatts of power per hertz (in the noise floor)

Radios can create output signal directly with digital techniques

High precision timing, but low complexity Graphics from

Scientific American: Wireless Data Blaster by David G. Leeper


Ultra-wideband Modulations Many ways to modulate

pulse streams No Multipath fading Main issue is precision

synchronization Applications

Communications Sub-centimeter

positioning Thru-wall/ground radar

Graphics from Scientific American: Wireless Data Blaster by David G. Leeper


Ultra-wideband Status Feb 2002: US FCC

allowed limited use Less than Part 15 levels

below 3.1Ghz Some restrictions on

applications Several Chip Vendors

Some samples XtremeSpectrum

Most announcements for mid to late 2003


Cognitive / Software Defined Radios Cognitive radio “understands” local

conditions and user requirements Will aggregate bands of spectrum that may

be allocated but not being used locally Software Defined Radio (SDR)

Radio signal modulated/demodulated in software

Can create arbitrary signals Could be Spread Spectrum, UWB or traditional


Status of SDRs Some commercial

implementations Very Limited Applications

like multi-band / multi-standard cell phones

Vanu Inc. SDR Software Developers

Kit Gnu-Radio

Open Source SDR Military most advanced

DARPA NeXt Generation Communications


Mesh Networks End points can relay

through other user nodes

Low Power Route around obstacles

Cooperation Gain Total Capacity of Mesh

increases with added users / relay nodes

Matches low power / high process gain tech like Spread Spectrum & UWB

Mesh Network Capacity vs Station Density

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Number of Stations

Total Capacity

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Per Station Capacity


Status of Mesh Networks Limited commercial deployment Nokia Rooftop

First generation product very limited throughput, proprietary and expensive.

For residential / infrastructure use only http://www.wbs.nokia.com/

Mesh Networks Inc. Initial product proprietary Promising an 802.11 based product that supports

infrastructure & end user relaying http://www.meshnetworks.com/

Long history of Military development


The SPTF Report

The Groundbreaking FCC Spectrum Policy Task Force

Report


Rather Incredible Document from a Federal Bureaucracy 9 months from start to finish Introduces and promotes several

concepts that would have been unthinkable only a year ago

Not perfect, several contradictory positions

Will mark a milestone for new regulatory thinking


Spectrum Rights Models Command and Control

Current style of regulatory policy Exclusive Use

Spectrum as Private Property Spectrum Commons

Technology used to share and manage spectrum


Command and Control Model Traditional management of spectrum for the last

80 years Government agency micromanages all spectrum

allocation FCC National Telecommunications and Information

Administration (NTIA) Spectrum allocated to a specific entity for a

specific use and specific technology Little or no flexibility how licensees can utilize

spectrum


Exclusive Use Model Allocates spectrum as property Spectrum holder can do whatever they want

with it Within the power and interference technical

requirements Can lease/resell all or portions to create

secondary markets Economists believe this will evolve spectrum

to its “Highest Value”


Spectrum Commons Model Unlimited unlicensed users share spectrum

via technological mechanisms 802.11 WLANs proved the value

Already US$2B Industry and growing rapidly Still rules and limitations on how Spectrum is

used Power per hertz, freq range, geographical, etc.

Marketplace of devices, services and technology


Creating a Spectrum Commons


Sharing Spectrum thru Technology, Not Politics

Spectrum is infinitely divisible Tech determines physical access to

usable spectrum Tech possibilities are just beginning

Most legacy systems are based on early 20th century technology

Cell phones and 802.11 use primitive sharing

Multi-dimensional real-time sharing by space, frequency, time, coding, mesh has no comparison to today’s limited capacity

Data Link (MAC)Network

TransportSession

PresentationApplication

Physical

EconomicsPolitics

802.11IP

TCP/UDP

234567

1

89


FCC SPTF Commons Suggestions

A Low Power Underlay Spread Spectrum, UWB, and other tech to utilize

new capacity in the noise floor of legacy systems Interference Temperature defines noise floor

Dynamic Reuse of idle spectrum Sense and utilize local spectrum being unused by

primary, release as soon as primary uses it. Geographical / Guard Bands Max power determined by local conditions + rules

set by FCC and/or primary licensee


Interference Temperature A paradigm for assessing the

interference in an environment A quantitative measurement that allows

for technology based access control to spectrum

Measures the RF power available at the receiving antenna per unit bandwidth.


Interference Temperature Metric to establish maximum permissible levels of interference Characterizes the worst case environment in which a receiver

would be expected to operate. Different threshold levels could be set for each band,

geographic region or service,


Creating an Underlay Commons

Distance from licensed transmitting antenna

Pow

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ver


Agile Radio Enables Dynamic Sharing Also known as Cognitive or Software Defined Radio

(SDR) Dynamically discovers + utilizes local unused

spectrum in real-time Takes advantage of “White Space” in spectrum allocations Releases slices of spectrum if primary licensee starts to use

it also Scales power based on application, local condition and rules

set by FCC and/or Primary Licensee Combine with Spread Spectrum and UWB


Example Agile Use of Spectrum

Channel6

Channel7

Channel5

Legacy uses such as TV do not allow adjacent channels in the same geographical location due to primitive receivers

Agile Radio could use low power channel 5 inside of channel 6 and 7 coverage areas

Could use any channel at higher power outside of their and adjacent channels in areas where they are not allocated


SPTF Recommendations Designate additional bands for unlicensed use Pursue secondary markets for use of licensed

spectrum Government granted easements to licensed

spectrum to enable a commons for low power non-interfering users

Promote spectrum flexibility in rural areas Promote experimental spectrum allocations


Some Public Responses


Big Bang Auction of Spectrum Championed by FCC Economists Evan Kwerel and John Williams Existing spectrum licensees incentivized to put “their” spectrum up

for auction Not required, but if they don’t, their use of the spectrum continues to be

bound by old rules Get to keep all the proceeds from their sale

Government (including military) puts all its spectrum in the auction Government can “buy back” spectrum for government (military, public

safety) or public “Spectrum Parks” Purchasers can aggregate spectrum Corporations or Organizations can buy spectrum for “unlicensed”

uses WiFi Alliance could buy spectrum for 802.11 for instance


Faulhaber & Farber Proposal Place all spectrum into the market, using Big Bang Ownership model: Fee simple with non-interference

easement I own the spectrum and have absolute use priority; others can

use it but only if they don’t interfere with this absolute use priority UWB, agile radio, mesh networks OK; “virtual commons” Monitoring and enforcement = transactions costs

Gov’t (at all levels) and private groups can own spectrum and make it available for commons use: “spectrum parks”


Concerns with Faulhaber & Farber Proposal Better than a pure Private Property Model Still assumes spectrum as private property should be

the dominant model Does not show that the benefits outweigh its costs Treats the Commons as a hedge

Still constrains Commons opportunity Promotes permanent grant of private property

Provides no revisability when technology or applications change

Not enough information to make such final and irrevocable decision


Technology based Commons Advocated by many technologists and

consumer advocates David Reed (MIT), Yochai Benkler (NYU School of

Law), Lawrence Lessig (Stanford) Dewayne Hendricks (Dandin Group) among others

New Tech utilizes spectrum more efficiently Works best with large swaths of spectrum Underlays & Agile radios can allow for transition

from legacy Industry Standards and technology manage most

sharing issues


National Association of Broadcasters (NAB)

Mostly concerned with protecting their existing “rights” Maintain that they are defenders of public interest with

“free” Television Against auctions because they undervalue the public interest

benefits Claim they are already “setting new standards in spectral

efficiency” Against commons for fear of interference with old radios

and TVs Consider the Cellular industry their biggest threat in terms

of spectrum


Cellular Telecommunications & Internet Association (CTIA)

Represents the Cellular / Mobile Phone Industry Aggressively supports spectrum policy reform

Cellular industry wants more spectrum for more capacity

Against “giving non-viable incumbents flexibility to provide any service” I.E. allowing TV stations to compete with Mobile

Phone Companies Against underlay in already allocated bands

Ok for new licenses where it can be explicitly stated


Motorola: Go slow, mostly licensed, some unlicensed ok Offered two technical papers

Good analysis of mesh networks Raises questions on ability of cognitive radios to

release spectrum fast enough Still seems more FUD to slow down new tech

Supports R&D in mesh and cognitive radios But not immediate roll out or licensing

Supports more unlicensed spectrum Some in 5Ghz, but most in 10Ghz and above


Satellite Broadcasting & Communications Association Protect DBS receivers from Terrestrial

Interference Concerned with sharing spectrum with terrestrial

Multi-channel Video Distribution and Data Service (MVDDS)

Against underlays and unlicensed spectrum Current DBS receivers are easily interfered with GPS is very sensitive to interference Fear of near channel overlap on satellite radio


National Association of Amateur Radio (ARRL)

Amateur Operators use to be radio innovators Since the IC and Digital revolutions Amateurs have

not been as involved Now are mostly legacy users

FCC should use the SPTF for planning No Big Bang / privatization of spectrum

Unless Amateur’s get their own “Public Park”

Concerns of unlicensed spectrum Proper policing of power and other tech constraints

Supports the need for regulation of receivers


Consumer Federation of America Pro-consumer advocacy organization Considers spectrum to be a “First

Amendment (Freedom of Speech) asset of citizens Privatization of spectrum would limit free speech

Selling of spectrum would accelerate consolidation of media

Supports Spectrum Commons


Microsoft: Unlicensed Spectrum will Unleash Broadband

Unlicensed wireless can break the broadband bottleneck Allows the Internet to “route around” incumbents

Telcos who are slow to build broadband Allows end users to finance broadband builds

Supports Spectrum Commons and additional unlicensed spectrum Believe there should be “rules of the road” to

facilitate sharing of spectrum


Cisco: Unlicensed Spectrum for the Network Revolution Similar to Microsoft’s points Some additional points of Cisco:

More commons, less private spectrum ownership

Don’t get stuck on international spectrum harmonization


XtremeSpectrum: UWB; new understanding of Interference Manufacturer of UWB technology Current vague definition of interference

be replaced by explicit definition The new “Interference Temperature is a

good start. Specify minimal capabilities of receivers to

reject interference Translate that into max permissible

emissions levels for underlay technology


Potential Action Items


Policy Recommendations

Avoid irrevocable and difficult to change policies Privatizing large amounts of spectrum would be difficult to reverse Technology is just beginning

Enable some form of “easements” on existing and new licenses to allow for underlays and agile radios.

Be explicit with legacy incumbent licenses Much of the issues of the report were concerning incumbents, but

were not openly discussed as such Treat incumbents as a transition issue, not assume that they should

be incumbents forever


Reality Checks Spectrum Utilization Audits

See how spectrum is really being used in various regions Analyze capacity of spectrum

Consider several dense usage scenarios using data from the spectrum audits and demand growth profiles

Calculate various spectrum utilizations with different technology assumptions

See how often there is really a “tragedy of the commons”


Consortium to develop Open Spectrum Technologies Open Spectrum will be a boon for

hardware device manufacturers Japan could lead in Open Spectrum

device technology A consortium to develop core

technologies could be highly leveraged Radio Haven in a secondary market

would be an excellent test environment


Status: Major Fork in the Road FCC & Industry split

Economists & Incumbents like Property Models

Technologists & Internet types like Commons

Surprising support for commons though

Boxer/Allen Senate Bill Pronouncements from

Chairman Powell considering making unused TV bands unlicensed