Transcript 1.2 ESA_Wireless_study_WP1

Network Protocol Trade-off for
Strawman Missions
Kawsu Sidibeh
Surrey Space Centre, University of Surrey, UK
ESA Wireless Study
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Agenda
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Wireless technologies in context
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WPAN protocol Comparisons
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WLAN & WMAN protocol Comparisons
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Recommendations & Conclusions
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Wireless Standards Date Rates and
Deployment
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Wireless technologies
By deployment :
•Wireless indoors: 802.15.4 (Industrial control and monitoring, Sensor networks,
building automation and home control
•Wireless Indoors : 802.15.1( Wireless connectivity between devices such as phones,
PDA, Laptops, headsets, etc.
•Wireless last mile : 802.11, 802.16 (WLAN connectivity, broadband internet access)
•Wireless overhaul/Backbone : 802.16 (MAN long range connectivity)
By mobility
•Vehicular speeds up to 75 mph : 802.16e
•Supplement 802.11p delivers mobility up to 125mph
•Vehicular speeds up to 155 mph: mobile-Fi (802.20)
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Wireless Protocol Stacks
OSI Model
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ZigBEE/802.15.4 STACK
BLUETOOTH STACK
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802.11 STACK
802.16 STACK
General Comparison ZigBee vs Bluetooth
ZigBee/IEEE 802.15.4 - General
Characteristics
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Dual PHY (2.4GHz and 868/915 MHz)
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Optimized for low duty-cycle applications
(<0.1%)
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CSMA-CA channel access
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Yields high throughput (max 250Kbps)
and low latency for low duty cycle devices
like sensors and controls
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Low power (battery life multi-month to
years)
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Multiple topologies: star, peer-to-peer,
mesh
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Optional guaranteed time slot for
applications requiring low latency
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Fully hand-shaked protocol for transfer
reliability
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Bluetooth –General Characteristics
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PHY ( ISM Band 2.4 GHZ)
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Optimized for audio, graphic, FTP,
ad hoc.
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Master-Slave Polling channel
access
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1 Mbps throughput
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Medium power consumption
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Max. 7 nodes per picocell
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Support TCP/IP connections
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High latency
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WPAN Protocol Comparison
ZigBee
Bluetooth
Ultra Wide Band
Data rate
20, 40, and 250 Kbps
1 Mbps
100-500Mbps
Range
10-100 meters
10 meters
<10 meters
modulation
DSSS
FHSS
N/A
Bandwidth
2 MHz
1 MHz
Very Large
Network topology
Ad-hoc, peer-to-peer, star or
mesh (255+)
Ad-hoc,Very small networks
(7)
Point-to-point
MAC
CSMA/CA
Master-Slave: Polling
N/A
Power consumption
Very low (Design Goal)
Medium
low
TCP/IP Support
No
Yes
Yes
Latency
Device Joining network in
30ms
Device connection requires
1s
Protocol stack
implementation
~ 32kb
256kb
?
security
128 AES plus app. Layer
security
64 and 128 bit encryption
?
I/O
SPI, Rs232, I2C
UART, Rs232, I2C
?
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Very low
General comparison 802.11 Versus 802.16
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802.11
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Widely deployed
Up to 54 Mbps on 20 MHz
(802.11n supplement up to 300500 Mbps)
Up to 300 meters
Qos support (802.11e supplement)
Not adaptable to PHY conditions
Smart antenna support (802.11n
supplement)
Weak security (enhanced in
802.11i)
Up 100 Mph Mobility ( 802.11p
supplement)
Power control (Dose)
2.4 GHz and 5 GHz (licensed)
802.16
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Experimentally deployed
Up to 100 Mbps on 20MHz
Up to 50,000 meters
QoS support ( Built in the
standard)
Adaptable to PHY conditions
Smart antenna support (both
MIMO & AAS)
Strong Security (built in the
standard)
Up to 75 Mph mobility( 802.16e)
Space Time Coding (2 TX + 1 Rx)
Power control (sleep & awake)
2-60 GHz (licensed & unlicensed)
WLAN & WMAN Protocol Comparison
Wi-Fi
(802.11)
Fixed WiMAX
(802.16.2004)
Mobile WiMAX (802.16e2005)
Data rate
1-25 Mbps
5-10 Mbps
5-10 Mbps
MAC
CDMA/CA
TDMA/DA
TDMA\DA
modulation
OFDM
OFDM
OFDMA
Range
300-10km
50 km
70 km
Bandwidth
Fixed, 20 MhZ/52 subcarriers
Variable; 1 to 28
Mhz/256 sub-carriers
Variable; 1 to 28
Mhz/2048 sub-carriers
Spectral Efficiency
2.7 Mbps/Hz
3.1 to 3.8 Mbps/Hz
3.1 to 3.8 Mbps/Hz
EVM Required
-25 dB
-31dB
-31dB
Receive Noise Figure
10 dB max
7 dB max
7 dB max
Duplexing
TDD
TDD, FDD, HFDD
TDD, FDD, HFDD
Mobility
>100 mph, Ad hoc
Transmit Dynamic range
Transmit power fixed
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Fix
75 mph
50 dB range
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50 dB range
Recommendations & Conclusions
ZigBee and Bluetooth for Intra-Satellite Links
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ZigBee for sensor networking, monitoring, control, etc on-board
Bluetooth for cable replacement.
Possibility of IR-UWB and Wi-Fi for high data rate requirements <1Mbps
Wi-Fi and WiMAX for Inter-Satellite Links
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Wi-Fi directional or mesh deployments in close proximity links such as satellite
clusters and formation flying.
WiMAX deployment to cover last mile (>10 Km) for inter-satellite connectivity in
LEO constellations such string of pearls.
Possibility of using ZigBee-Pro (up to 1.6 km) for sensor networking in intersatellite applications should be considered.
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