Post on 04-Apr-2018
7/29/2019 Mobile Networking for Smart Dust
1/27
Emerging Challenges: Mobile
Networking for Smart Dust
Naveen Gupt a
200301040
7/29/2019 Mobile Networking for Smart Dust
2/27
Outline Introduction
Off the Shelf Technology
What is Smart Dust
Vision
Smart Dust Technology
RF versus Optical Corner Cube Retro Reflector
Active Transmitter
7/29/2019 Mobile Networking for Smart Dust
3/27
INTRODUCTION
THREE KEY TECHNOLOGIES
Digital Circuitry Wireless Communications
Micro Electro Mechanical Systems
In each area, advance in hardwareTechnology, design led to reduction insize, power consumption and cost.
7/29/2019 Mobile Networking for Smart Dust
4/27
OFF THE SHELF TECHNOLOGY
7/29/2019 Mobile Networking for Smart Dust
5/27
What is Smart Dust
Large scale Networks of wirelesssensors of various applications
The three key capabilities of smart dustare:
Sensory Capabilities
Processing Capabilities
Communication Capabilities
7/29/2019 Mobile Networking for Smart Dust
6/27
Vision
Smart Dust will be small enough toremain suspended in air, buoyed by aircurrents, sensing and communicationfor hours or days on end.
7/29/2019 Mobile Networking for Smart Dust
7/27
Smart Dust Technology
7/29/2019 Mobile Networking for Smart Dust
8/27
Integration MEMS (Micro-Electro-Mechanical Systems)
Sensors
Semi Conductor laser diode MEMS beam-steering Mirror
Corner-Cube Retro reflector
Optical Receiver
Signal Processing and Control Circuitry
Power Source based on thick film batteries
Solar Cells
7/29/2019 Mobile Networking for Smart Dust
9/27
CHALLENGE To incorporate all these functionalities in a
cubic millimeter volume.
The total energy stored in the order of 1Joules.
Power Consumption cannot exceed over10microWatts.
7/29/2019 Mobile Networking for Smart Dust
10/27
RF versus Optical RF radio frequency
MHz hundreds of GHz -> 1mm 100s meters
wavelength Technologies:
Bluetooth
Cell phones (GSM, CDMA, etc.)
RFID
Optical 100THz 1PHz -> 0.3 - 1.6 micro wavelength
Lasers and LEDs
7/29/2019 Mobile Networking for Smart Dust
11/27
Radio Frequency Pros
Well developed technologies
Multiplexing techniques: TDMA, FDMA, CDMA.
Does not require line of sight
Not much affected by the environment
Cons
Antenna size (has to be at least of thewavelength)
Complex circuitry (modulation/demodulation,bandpass filters, etc.)
Energy consumption (approx. 100nJ/bit)
7/29/2019 Mobile Networking for Smart Dust
12/27
Optical (1/2) Pros
Low energy consumption (
7/29/2019 Mobile Networking for Smart Dust
13/27
Optical (2/2)
BTS (Base Transceiver Station)
Compact imaging receiver- decode thesimultaneous transmissions from a largenumber of dust motes at differentlocations within in the receiver field of
view
7/29/2019 Mobile Networking for Smart Dust
14/27
Corner-Cube Retro reflector To supply signals without
any power
It comprises threeperpendicular mirrors ofgold-coated polysilicon
CCR includes anelectrostatic actuator-deflects on of the mirrorsat kilohertz rates.
7/29/2019 Mobile Networking for Smart Dust
15/27
CCR Passive Optical (1/2)
Directional
CTS body diagonal happens to directlyto the BTS
Emerging More CCRS Omnidirectional
7/29/2019 Mobile Networking for Smart Dust
16/27
CCR - Passive Optical (2/2) BTS contains a laser whose beam illuminates
an area containing dust nodes
Modulated beam contain Downlink data +commands to wake up and Query
Analysis show that this uplink achievesseveral kbps + hundreds of meter in fullsunlight
Design is simple
7/29/2019 Mobile Networking for Smart Dust
17/27
Design of Free-Space Optical
Network
7/29/2019 Mobile Networking for Smart Dust
18/27
Smart dust act ive t ransmit t er
Incorporates a laser, lens and a MEMsteering mirror
Peer Peer Communication
Trade off between bandwidth and range
1mrad transmission
Data rate of approx. 5Mb/sec
Energy consumption depends on distanceand detector size
7/29/2019 Mobile Networking for Smart Dust
19/27
Base Station Architecture
Mirror
Camera Lens
Beam
Mirror
PolarizingBeam Splitter
PlateFilter
LaserExpander Smart
dust
7/29/2019 Mobile Networking for Smart Dust
20/27
Smart dust act ive
transmitter
~25nJ/bit1m2500km
~10nJ/bit1cm25km
~20pJ/bit0.1mm25m
Energyconsumption
Detector areaDistance
~25nJ/bit1m2500km
~10nJ/bit1cm25km
~20pJ/bit0.1mm25m
Energy
consumptionDetector areaDistance
7/29/2019 Mobile Networking for Smart Dust
21/27
Mobile Networking Challenges
Line of Sight Requirement
Link Directionality
Trade offs Between Bit rate, Distanceand Energy per bit
7/29/2019 Mobile Networking for Smart Dust
22/27
Line of Sight Requirement (1/2)
Optical communication requires photons from thetransmitter reach the receiver photons travel in
straight lines
Specular reflections
Diffuse reflections Feasible only when ActiveTransmitters are used over short distances (probably 1m) Note : Cannot work with passive communication ,very small SNR
7/29/2019 Mobile Networking for Smart Dust
23/27
Line of Sight
Requirement(2/2)
Dust Mote can communicate with theBTS via Multi hop Routing
Mote Density should be high
Multi hop routing increase latency
7/29/2019 Mobile Networking for Smart Dust
24/27
Link Directionality(1/2)General
Motes are unaw are of neighbours locat ion
Base st ation can disseminate location informat ion t o motes
Passive links
A corner cube retro-r eflector angle of acceptance is 10-20
Placing mu lt iple corner cubes Placing t he corner cube and t he receiver on a MEM
mount signal maximization
I ncrease mote densit y high probability forcommunication w it h at least some mot es in t he area of
interest
7/29/2019 Mobile Networking for Smart Dust
25/27
Link Directionality(2/2)Act ive links Mote receiver is omni direct ional w it hin a hemisphere
Enables mote at t ention w it hout aiming No source ident if ication
Making t he receiver di rect ional (by adding a lens) andconnect ing its directionalit y t o the transmit ter w illenable comm unicat ion autom at ically t o the source Requires aiming
Solved by increasing the densit y of motes I n a stati c syst em, ident ifi cat ion could be saved in m ote
memory Difference betw een receiver and transmit t er angular
spreads leads to non-reciprocal link ing
7/29/2019 Mobile Networking for Smart Dust
26/27
Mobile Networking Opportunities
Parallel Read Out
Demand Access
7/29/2019 Mobile Networking for Smart Dust
27/27
THANKS FOR YOUR
CO-OPERATI ON