RID: Radio Interference Detection in Wireless Sensor Networks Gang Zhou, Tian He, John A. Stankovic, Tarek Abdelzaher Department of Computer Sceince University of Virginia INFOCOM 2005

Outline Introduction Experiments on radio interference RID Simulation Conclusion

Introduction Interference-connectivity A B C

Introduction B A C

Interference-connectivity Connectivity-interference B A C

Introduction B A C

Experiments on radio interference ~Setup Weak link from T to R 16.2 feet 80% packet delivery ratio Strong link from T to R 8.5 feet 100% packet delivery ratio

Experiments on radio interference ~one direction Radio Interference for a Weak Link Radio Interference for a Strong Link

Experiments on radio interference ~diff. directions Interference Pattern Measured for a Weak Link Interference Pattern Measured for a Strong Link

RID: Radio Interference Detection Protocol HD-ND Detection Information sharing Interference calculation

HD-ND Detection HD packet (with a high sending power) ID information (2 bytes) Packet type (1 byte) To minimize the packet length and to save transmission energy T R HD packet

HD-ND Detection ND packet (with the normal sending power) The ND packet ’ s length is fixed in order that the receiver is able to estimate when the ND packet ’ s transmission will end once it starts to be sensed. T R ND packet

Rules the receiver uses The power level sensed in T1 is as low as that of the background noise On the contrary, receiver thinks this data is useful and records the (transmitter ID,power level) pair for later use Extremely weak, and doesn’t record any information

Add-on rule for receiver to detect disturbance The power level sensed during time period T1, is stable The power level sensed during time period T2, is always as low as that of the background noise.

Add-on rule for receiver to detect disturbance The power level sensed during time period T1, is stable Variable Sensed Power Level During T1

Add-on rule for receiver to detect disturbance The power level sensed during time period T2, is always as low as that of the background noise. Variable Sensed Power Level During T2

Add-on rule for receiver to detect disturbance Stable Sensed Power Level During T1 and T2

Information Sharing T1T1 R T2T2 T3T3 HD ND T1T1 P1P1 Interference_In table

Information Sharing T1T1 RT2T2 T3T3 HDND T1T1 P1P1

Information Sharing T1T1 P1P1 T3T3 P3P3 T1T1 R T2T2 T3T3 HDND T1T1 P1P1

Information Sharing T1T1 P1P1 T3T3 P3P3 APAPA RPRPR T1T1 R T2T2 T3T3 T3T3 P3P3 Interference_In table Interference_Out table Interference_HTP table

Interference Calculation N 2 (D) = {(i 1,i 2 )|(P i1D >receiver_sensitivity) ^ <SNR} i 1 : sender i 2 : jammer D : receiver D i 2 (jammer) i1i1 OK

Interference Calculation N 2 (D) = {(i 1,i 2 )|(P i1D >receiver_sensitivity) ^ < SNR } i 1 : sender i 2 : jammer D : receiver D i 2 (jammer) i1i1 Interference P i1D P i2D +P idle

Interference Calculation The composite of multiple negligible jammers is not necessarily negligible

All collision Scenarios in System N : the number of sensor devices actually deployed {D i } : the set consisting of all nodes in the system D 1 D D k N 2 (D 1 )={ _,_} N 2 (D 2 ) N 2 (D k ) N 3 (D 1 )={ _,_,_} N 3 (D 2 ). { _, _,_}..... N k (D 1 ) N k (D 2) N k (D k )

RID-B : Lightweight Radio Interference Detection Protocol T1T1 P1P1 T3T3 P3P3 T1T1 R T2T2 T3T3

RID-B does not take into consideration the interference cases when multiple transmitters get involved There is no interference calculation phase in RID-B

Simulation GlomoSim

Loss Ratio Simulation #Retransmission

Simulation #Control PacketsTransmission Time

Energy Consumption Simulation

Conclusion Our work is the first to detect radio interference relations among nodes in run- time systems The traditional TDMA protocol, NAMA, can have up to 60% packet loss in heavy load, while the RID-B supported TDMA, NAMA- RID-B, can maintain 100% packet delivery