simulations
DESCRIPTION
T cycle. BPS. BPS. BPS. S 1. D. S n. D. S 1. D. S n. D. BPS. BPS. COORDINATOR. Ch = CC. 50% Sensors Alive ?. Y. N. SENSOR. Send (CC). Y. ACK ?. Send (BC). N. Send (CC). Y. ACK ?. N. Y. ACK ?. TD. Send (CC). N. Send (BC). Y. ACK ?. CC ↨ BC. N. Y. ACK ?. - PowerPoint PPT PresentationTRANSCRIPT
Simulations
University of BresciaDepartment of Electronics for the Automation
A. Flammini, D. Marioli, G. Mazzoleni, E. Sisinni, A. Taroni
Email: {alessandra.flammini,giuseppe.mazzoleni,daniele.marioli,emiliano.sisinni,andrea.taroni}@ing.unibs.it Web Site: http://www.ing.unibs.it/~wsnlab/
On-line Coordinator floor noise monitoring (RSSI) in a 2 active channels architecture
Channel selection
Few retries for a fast reconnect time
STAR network topology: isochronous time slots allocation with ACK (Si)
Simulated Traffic: channel occupation
Power spectrum estimation
“Sniffer”
WUSB
RF section power consumption (@3.3V):
TX: 69mA, RX:60mA
Sleep: µA, Idle: 2.5mA
Rsh
un
t=1
.5Ω
INA110G=100
LeCroy LT374
TekRSA3408A
Test Bench:
802.15.4 Coordinator RF consumption802.15.4 Sensor RF consumption
RSSI as evaluated by RF transceivers
COORDINATORCOORDINATOR
COORDINATORCOORDINATOR
COORDINATORCOORDINATOR
BPSBPS
BPSBPS
BPSBPS
BPS: battery powered sensorBPSBPS
BPSBPS
Low transfer rate (tens bps)
Low cycle time (tens s)
Few sensors (Point to Point, Star Topology)
Several insulated star networks
Power supply / wired link
S1 D Sn D S1 D Sn D
Tcycle
Additional transceiver to scan all available channels
Reserved “diagnostic” time slot (D) where coordinator computes channels energy
Coordinator dynamically sorts channels according to their floor noise
Ch = BC
Y
COORDINATOR
50% SensorsAlive ?
Ch = CC
N
CC
↨BC
Channels divided in 2 groups
Selection of CC (Clear Channel), BC (Backup Channel)
No data from more than 50 % of sensors ? BC CC
Filtering of noise estimation
Performances evaluation varying floor noise FN, burst number BN and burst length BL
Comparison between the proposed solution and standard approach
Index of merit based on Cost where W represents weight of retransmissions (W =1) and rebinding procedures (W=26)
BN = 10, BL = 2000, N = 105, M=10 FN = 0.2 , BL = 2000, N = 105, M=10
M
1i
N
1jji,W
N
1
M
1Cost
FN = 0.2 , BN = 10, N = 105, M=10
M = Number of sensors, N = Simulation steps, W = Consumption weight
WUSB Coordinato
r
802.15.4 Coordinato
r
802.15.4 Sensor
WUSBSensor
802.15.4
RF section power consumption (@3.3V):
TX: 29mA, RX:33mA
Sleep: µA, Idle: 1mA
1.5m
1.5m
Tx power = 3 dBm, Transfer rate = 250kbps
Data payload = 100 bytes , ACK = 5 bytes
Duty cycle ~ 48 %
0
10
20
30
2405
2410
2415
2420
2425
2430
2435
2440
2445
2450
2455
2460
2465
2470
2475
MHz
RS
SI
CY
WU
SB
6934
[a.
u.]
-100
-95
-90
-85
-80
-75
-70
RS
SI
MC
1319
2 [d
Bm
]
CYWUSB6934
MC13192
Power spectrum and spectrogram as measured by RSA 3408A
Coordinator
Sensor
Simulations
Features:
Simulations
Actual wireless sensor scenario Proposed solution
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
0.2
0.4
0.6
0.8
1
Floor noise [a.u.]
No
rma
lize
d C
ost
WUSBProposed
0 10 20 30 40 500
0.2
0.4
0.6
0.8
1
Burst Number (BN)
No
rma
lize
d C
ost
WUSBProposed
0 2000 4000 6000 8000 100000
0.2
0.4
0.6
0.8
1
Burst Length (BL)
No
rma
lize
d C
ost
WUSBProposed
Five retransmission in case of no ACK; 2 attempts on CC plus 1 retransmission on BC then it waits for a variable time before to retry again on BC and finally on CC
BC is free ? CC BC
Rebinding procedure when failing condition remains for more than 2 cycles
Experimental Results
N
CC
↨BC
SENSOR
Send (CC)
ACK ?Y
Send (CC)
ACK ?
Send (BC)
ACK ?
Send (BC)
ACK ?Y
Send (CC)
ACK ? Y
TDY
Y N
N
N
N