Hierarchical Power Management in DTN with Traffic-Aware Optimization Hyewon Jun, etc ACM SIGCOMM, 2006
Start Point … Contacts discovered by two radios
Start Point…
Question Left In DTN, if rely only on the low power radio to discover contacts…? What if not?
This paper is targeting … Hierarchical power management scheme Traffic-aware Optimization
DTN Radio Discovery Power management modes Search: wake up periodically to discover a contact (wake-up interval) Contact: stay awake to exchange messages Dormant: remain asleep
Continuous Aware Mechanism (CAM) High power radio always stays awake to search for other nodes
Power Saving Mechanism(PSM)
Short-range-radio-dependent Power Saving Mechanism (SPSM)
Generalized Power Saving Mechanism (GPSM)
Power Management Schemes
Traffic-Aware Wake-up Interval Estimation Problem Statement For each node, find the wake-up intervals that leads to discovering enough contacts to deliver the traffic load while minimizing energy consumption. Problem Formulation Statistical contacts information Traffic load ……
Wake-Up Interval Estimation for PSM
Wake-Up Interval Estimation for SPSM
Wake-Up Interval Estimation for GPSM First, estimate the expected bandwidth on the link (i; j) for each pair of wake-up intervals(wh;wl) in a given set of discrete wake-up interval pairs: Secondly, find a set S ij of wake-up interval pairs that provide enough bandwidth to consume the expected traffic load on the link (i; j) ; Third, we find the pair of wake-up intervals (wh ij ; wl ij ) in S ij that will consume the least amount of energy; Finally, choose the minimum wake-up intervals wh i and wl i among wh ij and wl ij, respectively.
Performance Evaluation Main Goal Analytical model accurately predicts contact discovery Wake-up mechanisms save significant energy
Performance Evaluation Simulation Setup RWP MF 12 stationary nodes (grid) and 8 mobile nodes (ferries) Ferries visit each node in order and repeat the route Metrics Normalized energy consumption Delivery ratio Contact discovery ratio
Contact Discovery
Traffic-Aware Power Management
From the simulation… Traffic-aware optimization save considerable energy. Performance depends on mobility model: PSM vs SPSM. PSM with traffic-aware optimization achieves similar performance to GPSM, which indicates …
Summary Present a hierarchical power management in DTNs Traffic-aware optimization