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LLR-based Distributed Detection for Wireless Sensor Networks. 後卓越進度報告 蔡育仁老師實驗室 2008/01/07. High LLR. Low LLR. Binary Hypothesis Testing. LLR: Log Likelihood Ratio The received signal Observation noise: assumed to be. Distributed Detection Depends on Likelihood Ratio.
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LLR-based Distributed Detection for Wireless Sensor Networks 後卓越進度報告 蔡育仁老師實驗室 2008/01/07
High LLR Low LLR Binary Hypothesis Testing • LLR: Log Likelihood Ratio • The received signal • Observation noise: assumed to be
Distributed Detection Depends on Likelihood Ratio • LLR can be treated as the reliability of a sample value • Power allocation in WSNs • Power allocation in each sensor based on the instantaneous observed signal • Large absolute value of LLR High reliability Allocate more power; vice versa • Sequential detection in WSNs • Can reduce the number of required transmission with the similar detection performance • Ordering the message transmission based on the LLR can further reduce the number of transmission • Save more communication power
…… Fusion Center Power Allocation Depends on Log Likelihood Ratio in WSNs
H1 lnA LLR(N) 1 2 3 4 5 6 7 8 N lnB H0 Sequential Detection Depends on Log Likelihood Ratio in WSNs • The thresholds ln(A) and ln(B) depend on the target false alarm probability and miss detection probability
Simulation – LLR-based Power Allocation 100 90 80 70 60 Required power in percentage g Scheme 1, =4 50 o g Scheme 1, =6 o g Scheme 1, =8 40 o g Scheme 1, =10 o 30 g Scheme 2, =4 o g Scheme 2, =6 o 20 g Scheme 2, =8 o g Scheme 2, =10 10 o 0 -5 -4 -3 -2 -1 10 10 10 10 10 Detection error probability
60 55 50 45 40 35 30 25 20 15 -4 -3 -2 -1 10 10 10 10 Simulation – LLR-based Sequential Detection FSS Conventional Real Value T-SPRT Real Value T-SPRT Ordered Real Value T-SPRT Ordered Real Value T-SPRT Required number of transmission Detection error probability
Publications • Journal Paper • Yuh-Ren Tsai, “Sensing Coverage for Randomly Distributed Wireless Sensor Networks in Shadowed Environments,” IEEE Transactions on Vehicular Technology, vol. 57, no. 1, Jan. 2008. (SCI, EI) • Conference Paper • Yuh-Ren Tsai, Kai-Jie Yang and Sz-Yi Yeh, “Non-uniform Node Deployment for Lifetime Extension in Large-scale Randomly Distributed Wireless Sensor Networks,” in Proc. of IEEE International Conference on Advanced Information Networking and Applications (AINA2008), Okinawa, Japan, March 2008. • Yuh-Ren Tsai, and Jyun-Wei Syu, “Down-link CIR Spatial Correlation and CIR Prediction for CDMA Cellular Systems,” in Proc. of IEEE 2008 Vehicular Technology Conference (VTC-2008 Spring), Singapore, May 2008.