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Efficient Geographic Routing in Multihop Wireless Networks. Seungjoon Lee*, Bobby Bhattacharjee*, and Suman Banerjee** *Department of Computer Science University of Maryland **Department of Computer Sciences University of Wisconsin-Madison. Proceedings of the 6th ACM international symposium
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Efficient Geographic Routing in Multihop Wireless Networks Seungjoon Lee*, Bobby Bhattacharjee*, and Suman Banerjee** *Department of Computer Science University of Maryland **Department of Computer Sciences University of Wisconsin-Madison Proceedings of the 6th ACM international symposium on Mobile ad hoc networking and computing (MobiHoc '05) Chien-Ku Lai
Outline • Introduction • New Link Metric for Geographic Routing • Link Cost Types and Estimation • Simulation • Conclusions and Future Work
Introduction- Geographic Routing (Position-based Routing) • This kind of routings uses location information for packet delivery • Neighbors locally exchange location information • Neither route establishment nor per-destination state is required
Introduction- Normalized Advance (NADV) • Instead of the neighbor closest to the destination, NADV lets users select the neighbor with the best trade-off between link cost and proximity
Introduction- about this paper • For the effective use of NADV, this work presents techniques for efficient and adaptive link cost estimation • Providing multiple techniques thus enabling nodes to choose the best scheme for the current network and system setting
New Link Metric for Geographic Routing Background Normalized Advance
Background • Link cost • the power consumption required for a packet transmission over the link • Link metric • “degree of preference” in path selection
Background (cont.) • In many geographic routing protocols • The current node S greedily selects the neighbor that is closest to destination T
Background- Goal • To gain as large advance as possible for fast and efficient packet delivery • To balance the trade-off, so that we can select a neighbor with both large advance and good link quality
Link Cost Types and Estimation Packet Error Rate (PER) Delay Power Consumption
Packet Error Rate (PER) • Using Probe Messages for PER Estimation • Using Signal-to-Noise Ratio for PER Estimation • Neighborhood Monitoring for PER Estimation • Self Monitoring for PER Estimation
Packet Error Rate (PER)- Using Probe Messages for PER Estimation
: the received power : the transmission bit rate : the channel bandwidth : the complementaryerror function : thenoise power Packet Error Rate (PER)- Using Signal-to-Noise Ratio for PER Estimation • Assuming an AWGN (Additive White Gaussian Noise) channel, in the case of BPSK (Binary Phase Shift Keying), the bit error rate is given by
Packet Error Rate (PER)- Neighborhood Monitoring for PER Estimation • In IEEE 802.11 networks • using the MAC sequence number A can count how many frames from neighbor B it has missed • The quality of two directional links may differ
Packet Error Rate (PER)- Self Monitoring for PER Estimation • Aging • multiply PERs of unused links by 0.9 every 30 seconds
Delay • Two types of link delay • medium time • total delay – future work
Simulation Model Results
Simulation Model • Simulator: ns-2 • Deployment: uniform • Region: 1000m x 1000m • Nodes: 100 • Maximum transmission range: 250m
Conclusions • This work has introduced NADV as link metric for geographic routing • Geographic routing with NADV provides an adaptive routing strategy • is general • can be used for various link cost types • This work presented techniques for link cost estimation • NADV also finds paths whose cost is close to the optimum
Future Work • To design a link cost model that balances multiple cost criteria • To implement the NADV framework on real testbeds and evaluate the performance in practice
Question? Thank you.