White Space Networking

http://research.microsoft.com/en-us/projects/knows/

Microsoft Research

US White SpacesUnused VHF & UHF Television Frequencies

In the US, primarily the upper UHF "700-megahertz" band, covering television frequencies between 698 to 806 MHz (TV channels 52 to 69)

The White Spaces Coalition 8 large IT companies that want to enable high speed broadband internet

access in the 'white space' o Microsoft, Google, Dell, HP, Intel, Philips, Eathlink, and Samsung

FCC Nov. 4, 2008 RulingThe rules allow for both fixed & personal/portable unlicensed

devices.

Devices must include geolocation and spectrum-sensing technology. The geolocation data base will tell the white space device what spectrum may be used at that location.

The rules require that devices also include the ability to listen to the airwaves to sense wireless microphones.

The Commission will permit certification of devices that do not include the geolocation and database access capabilities, and instead rely solely on spectrum sensing subject to a much more rigorous “proof of performance” approval process.

Details…Fixed Devices w. Sensing & Geolocation

Personal / Portable Device w. Sensing & Geolocation

Personal / Portable Device w. Sensing Only

Channels(6 MHz each)

21-51 (except 37) ; fixed-2-fixed: 2 & 5-20 with exceptions

21-51 (except 37) 21-51 (except 37)

Transmit Power1 W (up to 4W with antenna gain)

100 mW (no antenna gain allowed)

50 mW (no antenna gain allowed)

40 mW (when licensed user is in adjacent channel)

Detection thresholds for ATSC, NTSC, & Wireless Microphones

-114 dBm -114 dBm -114 dBm

Database Registration

Yes No No

Beaconing for identification

Yes No No

In-service monitoring / Channel move times

Every 60 seconds / 2 seconds

Every 60 seconds / 2 seconds

Every 60 seconds / 2 seconds

Channel availability time

30 seconds30 seconds 30 seconds

Location Accuracy 50 meters 50 meters 50 meters

The Big PictureStrategy & Policy

Enagage with FCC to help them nail down sensible specificationsWorld-wide evangalism with regulatory bodies (e.g. OFCOM, SARFT, TRAI)Enagage with silicon vendors & systems integrators

ResearchIdentify technical issues & solve the hard problemsBuild prototypes as proof of solution - learn from those & refine technologyHelp the startegy & policy teams with data for FCC & WRC forumsHelp BGs with scenario planning, standardization, & technology assets

BusinessDevelop application scenarios and possible revenue modelsForge strategic & complimentary alliances

ProductRamp up by gathering requirements & nailing down specificationsWork to establish a standard that reduduces cost of WSDsHarden research code, develop & test software for Windows

MSR's KNOWS Research ProgramNetworking Challenges

How should nodes connect?

Which protocols should they use?

Which mathematical tools should we use to reason about capacity & spectrum utilization?

How should they discoverone another?

Which spectrum-band should two cognitive radios use for transmission? • Center Frequency, Channel Width,

Duration…?

How should the networked nodes react upon arrival of a primary user?

MobiHoc 2007

MSR's KNOWS ProgramPrototype Development

Version 1: Ad hoc networking in white spaces700 MHz operation, TV sensing capability, one-to-one opportunistic networking, control-channel based MAC, varying channel width operation, multi-radio design, design analysis through simulations

Version 2: Infrastructure based networking (WhiteFi)

White Space freq. operation TV sensing Capability, limited microphone sensing, one-to-many opportunistic networking, Wi-Fi MAC, time-domain analysis (SIFT), demo-ed at internal events (e.g. TechFest 2009)

Version 3: Campus-wide backbone network (WhiteFi with Geolocation)

All of V2 + geolocation DB, Windows network stack improvements, bridging between Wi-Fi and WhiteFi, coverage in MS Shuttles

Dynamic Channel WidthVarying channel width can reduce energy consumption, increase range & improve spectrum utilization

Time Spectrum BlockCommunicate by allocating TSBs defined as {Fc, dF} & {Tb, dT}. A distributed (fair) algorithm for determining TSBs is possible

Control Channel based Medium Access Control

Wi-Fi MAC modified to accommodate opportunistic networking

Version 1: Major Innovations

Network Layer (TCP/IP)

CMAC(Collabora

tive Sensing & Access)

Reconfigurable Radio

Scanner Radio

ReconfigurationInterface

PHY Layer

bSMART(Spectrum Allocation

Engine)

Resource Allocation

Matrix

Sig

nal S

tren

gth

FrequencyFrequencyS

ign

al S

tren

gth

SIGCOMM 2007, DySPAN 2007

Version 2: Major InnovationsEliminated Control Channel & reused Wi-Fi

Spectrum Assignment Algorithm

Enables AP to pick a channel that is free for all clients AND pick the best possbile channel width

Discovery MechanismEnable clients to quickly discover an AP over all <channel, width> pairs

Fast Recovery after Disconnection

Re-connects quickly on a new available channel upon sensing a primary user on existing channel

WS Radio

PCSDR

UHF Transmissions

UHF Rx Daughterboar

d

Altera FPGA

Connection Manager

Serial Control Interface

FFTTV/MICDetectio

n

Raw (I, Q)

Temporal Analysis(SIFT)

Wi-Fi Substrat

e

UHFTranslator

Net Stack

(fc, df)(fc, df)

Device Driver (Atheros)

Best PaperSIGCOMM 09

Version 3: Campus Wide White Space Networking (WhiteFi w. Geolocation)

3-13-2

4-1

6-1

5-3

5-2 5-1

1-2

1-1

6-2

4-2

FCC Experimental License (Granted: July 6, 2009)

Centered at (47.6442N, 122.1330W)

Area of 1 square mile

Perimeter of 4.37 miles

WSD on 5-10 campus buildings

Fixed BS operate at 2 W EIRP

WSD inside shuttles at 63 mW

First White Space Network in the WorldWhite Space Network Setup

Microphone testing in Anechoic Chamber

Data packets over UHF

Subcarrier Suppression demo

Oct. 16, 2009

WS Antenna on Bldg 42

Shuttle Deployment

WS Antenna on MS Shuttle

Channel Occupancy Database

Click here for a live demo

WhiteFi and Broadcast TVWhiteFi Antenna TV Antennas

Microsoft Campus Redmond (Bldg 41)

WhiteFi transmitting at 40 mW

KOMO (Ch. 38) KIRO (Ch. 39) WhiteFi (Ch. 40)

WhiteFi (Ch. 40)

Future Hardware: SDR on Multicore with 700 MHz front-end

Application

Transport

Network

Link-layer Processing

PCIe BusLPA/

Sampling Convertor/D

AC/ADC

Latency critical radio

control (AGC/PD)

AntennaSD

R

Managem

ent

Flexible RF Hardware

Multi-co

re S

oftw

are

R

adio

Sta

ck

MAC Processing

Baseband Processing

Multi-core ProcessorsParallelization to accelerate PHY layer processingExploit GPP architecture for BB processingReduced heating

Ongoing work in MSR Asia

Best PaperNSDI 2009

Policy & Research Influence

Panel on "Broadband Spectrum: A Looming Crisis?" FCC's National Broadband Plan -- Field Hearing on Mobile Broadband, San Diego, CA, Oct. 8, 2009 

• Panel on "Innovating in Spectrum Access—Technological Advances and Other Approaches to Facilitate More Productive Spectrum Use" FCC’s National Broadband Plan -- Spectrum Workshop, Washington D.C. Sept. 17, 2009

• Panel on “Research Recommendation for Broadband Task Force,” Federal Communications Commission's National Broadband Workshop, Washington, DC (Nov. 23, 2009)

• Panel on Reactions and Perspectives, National Science Foundation Workshop on Future Wireless Communication Networks, Arlington, VA (Nov. 2-3, 2009)

India

China

Brazil

Radiocommunication Sector

Standards

Federal Communications Commission

Policy

Fisher Communications Inc.Industry Partners

Public Demos & Policy Influence

On-going Collaborations

Smart antennas, interference mitigate &

internationalization

Chanel occupancy database design &

related issues

White space mesh networks for rural

communities

Security & privacy in white space networks

Harmonization betweenheterogeneous white space

networks

The SORA Program

Steering Committee

MSR Event

Special Issue Editor

In the News

The project, dubbed “White Fi,” is one of the most advanced in the field, both dealing with the hardware side but also creating the networking protocols to handle the specific challenges.

Softpedia (Aug. 19, 2009)

Microsoft researchers have taken a step closer to finally turning unused analogue TV spectrum, known as "white spaces", into unlicensed spectrum that can be used to deliver new wireless broadband service

CNET.COM (Aug. 19, 2009)

The Microsoft Research team has addressed many of these issues with WhiteFi. —that early promise of "WiFi on steroids" might turn out to be surprisingly accurate, after all.

Nate Anderson, Ars technica, August 27, 2009

The actual engineering requirements to accomplish this frequency switch are non-trivial. Microsoft Research’s ”KNOWS” project has taken up the task and made some pretty remarkable advances.

Scott Merrill, Crunchgear, August 28, 2009

One of the best prospects for the future is the opening up of “white spaces,” unused parts of the spectrum. One of the most advanced research projects…..

Lucian Parfeni, Web News, August 18, 2009

Microsoft researchers have taken the next step toward turning old UHF analog TV spectrum into rural wireless broadband networks that would operate like Wi-Fi but with greater range.

Simon Juran, GigaOm, August 18, 2009-09-02

Press – Sample Quotes

Thanks

http://research.microsoft.com/nrg/

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