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Self-Management in Chaotic Wireless Deployments. A. Akella, G. Judd, S. Seshan, P. Steenkiste Carnegie Mellon University. Outline. INTRODUCTION IMPACT ON END-USER PERFORMANCE TRANSMISSION POWER AND RATE SELECTION PERFORMANCE EVALUATION CONCLUSION. INTRODUCTION. Chaotic Wireless Networks
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Self-Management in Chaotic Wireless Deployments A. Akella, G. Judd, S. Seshan, P. Steenkiste Carnegie Mellon University
Outline • INTRODUCTION • IMPACT ON END-USER PERFORMANCE • TRANSMISSION POWER AND RATE SELECTION • PERFORMANCE EVALUATION • CONCLUSION
INTRODUCTION • Chaotic Wireless Networks • Unolanned • Unmanaged • Suffer from • serious contention • poor performance • security problems
INTRODUCTION • To improve end-user performance • Automatically manage the transmission power levels • Transmissions rates of APs and clients.
INTRODUCTION • Power control algorithm called • Power-controlled Estimated Rate Fallback (PERF)
IMPACT ON END-USER PERFORMANCE • Simulation GloMoSim Topology
IMPACT ON END-USER PERFORMANCE • Simulation assumptions: • Each node on the map is an AP • Each AP has D clients with 1 ≤ D ≤3 • Clients are within 1 meter from their AP and they don’t move • All APs transmit on channel 6 • All APs use fixed power level of 15dBm • All APs transmit at fixed rate 2Mbps • RTC/CTS is turned off (default settings)
IMPACT ON END-USER PERFORMANCE • http with thinking time by Poisson distribution with mean equal to 5s or 20s • Comb-ftpi, i clients run FTP transmission • Results: • HTTP: 83.3 Kbps for 5s 24.5 Kbps for 20s • FTP:0.89 Mbps for 300s
IMPACT ON END-USER PERFORMANCE • Two simple mechanisms on mitigating interference • Use an optimal static allocation of non-overlapping channels • Reduce the transmit power levels
Non-overlapping channel assignment IMPACT ON END-USER PERFORMANCE
IMPACT ON END-USER PERFORMANCE Three non-overlapping channels 1 6 11 Only channel 6
IMPACT ON END-USER PERFORMANCE • Transmit power control
IMPACT ON END-USER PERFORMANCE • Managing power control and using static allocation of non-overlapping channels can reduce the impact of interference on performance
TRANSMISSION POWER AND RATE SELECTION • PARF: Power-controlled Auto Rate Fallback • Based on ARF • It Attempts to elect the best transmission rate • adding low power states above the highest rate state. • Power is repeatedly reduced until • the lowest level is • the transmission failed threshold is reached
TRANSMISSION POWER AND RATE SELECTION • PERF: Power-controlled Estimated Rate Fallback • Based on ERF(SNR+ERF): • It uses path loss information to estimate the SNR with which each transmission will be received • The transmission power is reduced to estimatedSNR = decisionThreshold + powerMargin
CONCLUSION • Power control and rate adaptation can reduce interference • Reduce power as long as transmission rate was unaffected.