Yang Yang lun Xu Da Cheng Li-hua Wu Peng-ju Tan Lin-tao Yang

Department of Electronic Information, Wuhan University, Hubei, Wuhan 430079, China

報告： 史晉銘 組員： 69821009 史晉銘

69821024 江宗儫69821044 葉人誠

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OutlineIntroductionBackground and Related WorkExperimental Setup and DetailsExperimental Results and AnalysisConclusion

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IntroductionThe performance of VANET is the most significant issue

Our application aim to provide continuous update about traffic conditions, which can assist the quality prediction of wireless link and the protocol design of VANET

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Experimental Setup and Details

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Experimental Setup and DetailsRSSI(Received Signal Strength Indicator); PLR(Packet

Loss Rate)IBM laptop computerWi-Fi (Antenna higher than 3.2 m )Broadcast data rate : 1Mb/sLeading vehicle(TX) Receiver vehicle(RX)

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Experimental Results and AnalysisEffect of Environmental Diversity to Wireless LinkEffect of RSSI to VANET Wireless LinkPredicting the VANET Wireless Link by PLBL

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Effect of Environmental Diversity to Wireless Linkthe averages of the PLRs are different

in various distance scalesIn distance range in 30m, the

performance of the two scenarios almost the same (the variation is less than 2%)

beyond 30m, the averages of PLRs of the urban scenario are superior to that of the suburban scenario

in 70m area, the difference of the two scenarios is between 10-15%

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Effect of RSSI to VANET Wireless Link

over 70m, the average of PLRs

tends to be lower; however, the RSSI is still worse

Comparing 50-60m 70-80m, the reductions of the average of PLR is about 15, even though the RSSI of them is very

The same results arerevealed in different distances

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Predicting the VANET Wireless Link by PLBL

The packet sequence is represented as a binary sequence {Xk}. If the kth packet is lost, Xk = 1; while the kth packet is receives, Xk=0

A burst is defined as a string of consecutive ones between two zero and PLBL is defined to be the number of ones

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Classified as two condition as follow: Suppose {0110} : The packet lose are consecutive Suppose {0101} : The packet lose of signal packet error is random

Let P be defined as the packet loss rate

s : {0110,01110,011110,….}; the possibility of the

Constant Packet Loss Ratet : {010}; the possibility of the Random Packet Loss Rate

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Predicting the VANET Wireless Link by PLBL

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ConclusionEnvironment affects the quality of the wireless link

in VANET greatlyAt the communication distance range, in most extend, the

PLR is related to the distance variationRSSI is not coherent with PLR, which is not helpful

in predicting the quality of the VANET wireless linkIn certain aspects, the sum of possibilities of PLBL is

another way to predict the 802.11 wireless channel quality

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Q&A

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