1 Testing the Impact of Radio Testing the Impact of Radio Impact - PDF document

GOAL GOAL Impact of Radio Irregularity Impact of Radio Irregularity � Modify the current isotropic radio models Modify the current isotropic radio models � assumed in simulation to account for the assumed in simulation to account for the on Wireless Sensor Networks on Wireless Sensor Networks non non- -isotropic radio properties that occur in isotropic radio properties that occur in reality reality Written by Gang Zhou, Tian Tian He, He, Sudha Sudha Written by Gang Zhou, Krishnamurthy, John A. Stankovic Stankovic Krishnamurthy, John A. Presented by Danna Gurari Presented by Danna Gurari Summary of What Will Be Summary of What Will Be What is Radio Irregularity What is Radio Irregularity Discussed Discussed � Prove that the effects of radio irregularity are Prove that the effects of radio irregularity are � � Irregularity in radio range Irregularity in radio range significant and show there is a need to significant and show there is a need to � characterize the irregularity in network characterize the irregularity in network � Irregularity in the number of packets lost Irregularity in the number of packets lost � simulators simulators depending on the direction of packet depending on the direction of packet � Provide a model that accounts for radio Provide a model that accounts for radio � irregularity irregularity transmission transmission � Using the proposed model, test simulated Using the proposed model, test simulated � networks and prove there is a need for routing networks and prove there is a need for routing Packet Transmission protocols to handle radio irregularity protocols to handle radio irregularity � Offer solutions that may allow for current Offer solutions that may allow for current � Mote Mote routing protocols to overcome the effects of routing protocols to overcome the effects of radio irregularity radio irregularity Causes of Radio Irregularity - - Causes of Radio Irregularity - - Causes of Radio Irregularity Causes of Radio Irregularity Devices Media Devices Media � Heterogeneous Properties of Devices Heterogeneous Properties of Devices � Non Non- -isotropic Properties of the Propagation isotropic Properties of the Propagation � � Media Media � The following are some contributors: The following are some contributors: � � The following are some contributors: The following are some contributors: � � Antenna Type Antenna Type � � Media Type Media Type � Sending Power Sending Power � � � Antenna Gain at Transmitting Mote Antenna Gain at Transmitting Mote � Background Noise Background Noise � � � Antenna Gain at Receiving Mote Antenna Gain at Receiving Mote � Fluctuation in Temperature Fluctuation in Temperature � � � Signal Signal- -Noise Ratio Noise Ratio � Presence of Obstacles Presence of Obstacles � � � Batteries for devices Batteries for devices � Effect from non Effect from non- -isotropic properties of media isotropic properties of media � � � Effect from heterogeneity of devices Effect from heterogeneity of devices � Radio Frequency signals are reflected, diffracted, and Radio Frequency signals are reflected, diffracted, and � � scattered scattered � Radio Frequency signals from the same kind of Radio Frequency signals from the same kind of � devices transmit different signal strengths � Therefore, irregularity in radio range and loss of Therefore, irregularity in radio range and loss of devices transmit different signal strengths � transmitted packets transmitted packets � Therefore, irregularity in radio range Therefore, irregularity in radio range � 1

Testing the Impact of Radio Testing the Impact of Radio Impact of Radio Irregularity Impact of Radio Irregularity Irregularity on Protocol Irregularity on Protocol Performance Performance � Asymmetric links: Asymmetric links: � � On actual motes? On actual motes? � � Transmission of messages in both directions Transmission of messages in both directions � � No! Expensive to test with large quantities of motes. No! Expensive to test with large quantities of motes. � may be inhibited may be inhibited Challenging to obtain similar data in an uncontrolled Challenging to obtain similar data in an uncontrolled � Effect: networks that communicate in both Effect: networks that communicate in both environment. environment. � directions may become inefficient/ineffective directions may become inefficient/ineffective � In a simulator? In a simulator? � � Non Non- -spherical radio range spherical radio range � Yes! Both problems in hardware are avoided when Yes! Both problems in hardware are avoided when � � testing with a simulator. testing with a simulator. � Protocols based on the assumption of Protocols based on the assumption of � � Problem Problem… … Current simulators do not account for Current simulators do not account for � spherical radio range are tainted spherical radio range are tainted radio irregularity radio irregularity Experiment Experiment Results Experiment Experiment Results � Before accounting for radio irregularity in Before accounting for radio irregularity in � � Experiment Set Up: Position sender mote, Experiment Set Up: Position sender mote, � simulation, testing was done to learn about simulation, testing was done to learn about position receiver mote 10 feet away, and position receiver mote 10 feet away, and radio irregularity radio irregularity measure signal strength, packet loss ratio, and measure signal strength, packet loss ratio, and � Experiment Requirements: Experiment Requirements: � range. Repeat this measurement from three range. Repeat this measurement from three � Mica2 Motes and Parking Lot Mica2 Motes and Parking Lot � other directions other directions � Experiments: Experiments: � � Received Signal Strength � Received Signal Strength � Packet Reception Ratio Packet Reception Ratio � � Communication Range Communication Range � Summary Isotropic Radio Model Summary Isotropic Radio Model � So far So far… … � � Signal attenuation is the same in all Signal attenuation is the same in all � � Proven that the effects of radio irregularity Proven that the effects of radio irregularity � directions directions are significant and have shown there is a are significant and have shown there is a need to characterize the irregularity in need to characterize the irregularity in Received Signal Strength = = Sending power Received Signal Strength Sending power – – Path Loss + Fading Path Loss + Fading network simulators network simulators Determined by battery Signal’s energy loss � Next will Next will… … � status, type of transmitter, as it travels to the amplifier, and antenna receiver � Provide a model that accounts for radio Provide a model that accounts for radio � irregularity irregularity 2