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A Low-latency and Energy-efficient Scheduling Algorithm for Multi-group Multicasting in Mobile Ad Hoc Networks Advisor: Professor Frank Y. S. Lin Presented by Pei-Wei Li. Outline. Introduction Problem Description Problem Formulation Lagrangian Relaxation. Introduction.
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A Low-latency and Energy-efficient Scheduling Algorithm for Multi-group Multicasting in Mobile Ad Hoc Networks Advisor: Professor Frank Y. S. Lin Presented by Pei-Wei Li
Outline • Introduction • Problem Description • Problem Formulation • Lagrangian Relaxation
Introduction • In MANET, multicasting is the fundamental operation of many applications, including military communications, emergency relief and video conferencing, which require time-critical information. • Power is a valuable resource in MANET due to the limited battery capability of nodes. • The mobility of nodes in MANET causes the topology of the network to rapidly change.
Introduction • There is an interesting trade-off between energy consumption and end-to-end latency of multicast when the transmission radius of a node is adjustable . • Case 1: transmission radius ↑ • latency ↓ • link holding time ↑ • energy consumption ↑ • Case 2: transmission radius ↓ • latency ↑ • link holding time ↓ • energy consumption ↓
Step1: construct a multicast tree for each multicast source to reach its group members Step 2: schedule the transmission time of the nodes on these multicast trees and avoid the collision of transmission Objective: minimize the latency of multicasting Consider the mobility of nodes and the energy consumption of transmission.
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Problem Description t1+t2+t3
Problem Description • Assumption • We get the location and mobility information of all nodes from GPS. • Prediction of velocities and oncoming positions of nodes can be provided by Gauss-Markov mobility model. • Transmission time can be divided into discrete slots. • All nodes in the network have their clocks synchronized. • Packet propagation delay can be ignored. • Each multicast source has single data to send.
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