Frequency Agility in a ZigBee Network for Smart Grid Application - - PowerPoint PPT Presentation
ILLINOIS INSTITUTE OF TECHNOLOGY Frequency Agility in a ZigBee Network for Smart Grid Application Peizhong Yi, Abiodun Iwayemi, Chi Zhou Optical Wireless Integration Lab Electrical and Computer Engineering Department Illinois Institute of
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10 10 10
4 20log ( ) , ( ) 4 20log ( ) 10 log ,
p
d d d L d d d n d d d π λ π λ ≤ = + >
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Zigbee Packet ACK WLAN packet
A C K
TACK,Z UZ TCCA
WLAN packet
A C K
LW LW TACK,
W
UW TSIFS TDIFS TC TC TW LZ TSIFS TZ
WLAN packet
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/ /
z c c
N T b T b I b b
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1 2 3 4 5 6 7 10
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10 BER 2MHz offset 3MHz offset 7MHz offset 8MHz offset Distance (m) 10
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1 2 3 4 5 6 7 10
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10 D i st ance P E R P E R w i t h i nt er f er ance 2M H z of f set 3M H z of f set 7M H z of f set 8M H z of f set
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Send a Packet Start ACK received? NACK Counter = NACK Counter+1 NACK Counter >threshold NACK counter=0 Channel change Yes No No Yes ED on current channel NACK = 0 RSSI > threshold ? No Yes Done
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2412 MHz 2400 MHz
Channel 1 Channel 6 Channel 11
22 MHz 2437 MHz 2462 MHz 2483.5 MHz
IEEE 802.11b North American Channel Selection
2410 2400 MHz
Channel
2 MHz 2435 2460 2483.5 MHz
IEEE 802.15.4 Channel Selection (2.4GHz PHY)
2405 2415 2425 2420 2430 2445 2440 2450 2470 2465 2475 2455 2480
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ED on channel class i Find available channel? available channel i1,i2...ik m=1 i = i+1 No Yes Active scan channel im Channel
No Yes Channel change Interference detected i=1 i>3 ? No Yes m = k? m = m+1 Yes No
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2 7 8 13 5 10 15 20 25 30 35 40 Experimental PER Offset Frequency (MHz) PER (%)
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2 7 8 13 50 100 150 200 250 LQI Offset Frequency (MHz) LQI
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