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WINS NG Networks

Networking Research ReviewSenseIT PI MeetingOctober 7-8, 1999

Marina Del Rey

Presentedto

Dr. Sri KumarDARPA/ITO

bySensor.com

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Outline

• Distributed Sensor Requirements– Communication system

• propagation

– RF modem signalling choices– Multihop and scalability– Networking architectures

• WINS NG Communication and Networking System Advances

• WINS NG Complete end-to-end system

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Network

enodenode

user

server

serverapplications

node

node node

node

node

node

node

node

internet

mobile node

node

nodenode

remoteuser remote

user

node

node

node

wireline LAN

user

Gateway node

Gateway node

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Network Requirements

• Nodes:– compact, energy limited sensors– deployed on the surface– deployed in structures

• Gateways:– wireline links (development)– long range wireless links (tactical)– local user displays

• Robust, redundant, self-assembled

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Propagation

• Communication Energy vs. Range– (Energy required for 1 kb

data payload)– Surface-to-Surface– 1/R4 propagation– (BPSK transmission and

a required error rate of 10-6)

0.1 1 10 100 1k 1000k

Distance (m)

En

erg

y (J

ou

les)

10k 100k

1k

100

10

1

100m

10m

1m

0.1m

Gaussian Channel

Rayleigh Channel

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Propagation

• Communication Energy vs. Range– (Energy required for 1 kb

data payload)– Conventional Free-

Space systems– 1/R2 Propagation– (BPSK transmission and

a required error rate of 10-6)

0.1 1 10 100 1k 1000k

Distance (m)10k 100k

1k

100

10

1

100

10

1m

0.1m

En

erg

y (J

ou

les)

LAN80kb

Cellular30 kbps

Satcom2.4kb

Free SpaceGaussian Channel

Free SpaceRayleigh Channel

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Propagation• Propagation

– Ground wave influence

– 1/R4 propagation law

• Measurement– WINS nodes– 2.4 GHz band– observe large

variation in RSS

-50

-40

-30

-20

-10

0

1 10

Range (m)

Re

ceiv

ed

Po

we

r (d

Bm

)

2 4 6 8

1/R4

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RF Modem Signalling Choices

• Simple baseband modem– single frequency– limited power due to FCC

compliance constraints– not robust against

multiuser interference– limited surface-to-surface

link capability– may be ideal for tag

systems

data

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RF Modem Signalling Choices

• Direct sequence modem– FCC compliant– large spreading at high

power: • robust against multiuser

interference

– narrow spreading at low power:

• limited robustness and surface-to-surface link capability

– low cost

data

code

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Signalling• Frequency hop• Global commercial trend

– Special considerations for short range tactical links

– Regulatory compliance met

– Multiuser capability

– Low power cost associated with high performance and robust operation

– Adaptive hopping patterns

– Adaptive hopping rate

– Robust operation observed in the field - weeks of error free operation

• Requires acquisition

data

FS

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Networking Strategy

• Master/slave radio architecture– Master defines hopping

pattern– Master acquires– Slave follows– WINS NG

• every node may function in either mode

• reconfiguration at any time• self-assembled

Master 1

Slave

Master 2

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Multihop, Scalability, Fault Tolerance

• Multicluster– aggregation of nodes exploits

local area environment constraints

– cluster aggregates local area information

– clusters support robust diversity of connectivity paths (Nodes/Gateways)

– cluster derives summary messages

– natural scalability advantages– different clustering at higher

layers

Master

Slave

Gateway

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WINS NG Communication and

Networking

• WINS NG Communication and Networking API Specification Upgrades– Transmitter power control

• derive further energy advantages from multihop

– Received signal strength– Variable hop rate– Hierarchical addressing– Network assembly

• mobility

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• Complete end-to-end WINS NG System

– Node• geophone sensor

– Gateway (WINS Network)

– WINS Server (Telephony)

– WINS SQL Server (IP)

– Web Access (IP/ASP)

– Auto-assembly

– Fault tolerance

– Example Application:• event driven Node to Gateway to

Server data transfer

WINS NG System

enodenode

user

server

serverapplications

node

node node

node

node

node

node

node

internet

mobile node

node

nodenode

remoteuser remote

user

node

node

node

wireline LAN

user

Gateway node

Gateway node

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