1. Trajectory Based Forwarding
Group 2
Andrew Doherty, Aaron Wroblewski, Raghav Chawla
Raghav

2. Introduction Dynamic Source Routing (DSR)
High Overhead in Dynamic, Dense, Low Power Sensor Networks
TBF Combines DSR with Cartesian Forwarding
Source Specifies a continuous path, and then nodes forward based on distance from the path
Trades Communication for Computation
Raghav

3. Background and Motivation
Advances in MEMS technology allow for large scale, highly dense ad-hoc sensor networks
Smartdust, disposable networks, etc
Wireless Sensor Networks face different problems than Wired Networks
Potentially millions of nodes
Battery life, mobility of nodes, sleeping nodes
Raghav

4. The Problem Statement
Problem: How can we efficiently forward packets in a dense ad-hoc network, while dealing with issues of scalability and a dynamic network topology?
Previous Approaches
Source based routing has problem of packet overhead increasing with path length
Cartesian routing defines a single forwarding policy: greedy, along a straight line
Raghav

5. General Overview
TBF is a hybrid between Source Based Routing and Cartesian Forwarding S
Andrew D D

6. Forwarding Methods “Minimum Deviation” (N2) MFR (N4)
Centroid of the Set (N3)
Most Battery Left
Random
Andrew

7. Applications of TBF Unicast Routing Multipath Routing Mobility
Discovery
Broadcasting
Multicast
Aaron

8. Adverse Conditions Sparse Networks Imprecise Locations Loop Method
Alternatives to Positioning (GPS)
LPS – Local Positioning System
DV-Hop
Aaron

9. Performance Evaluation Model
Simulations were run to test:
Unicast Routing and Discovery
Broadcasting
Location Data Dependence
Aaron

10. Unicast Routing and Discovery
Andrew

11. Naïve Broadcasting
Andrew

12. Optimized Broadcast
Andrew

13. Exploring Location Data
Aaron

14. Location Data Dependence
Deviation decreases with density
Small difference in deviation between routing with warped or true positions
Warped network not always longer
TBF robust in face of realistic corruptions of node positioning
Aaron

15. Related Work “Position Centric” Routing “Node Centric” Routing
Routers responsible for polygonal regions
Cartesian Routing
LAR (Location Aided Routing)
“Node Centric” Routing
DSR (Dynamic Source Routing)
Terminode Routing
“Data Centric” Routing
Routing driven by Interests
Aaron

16. Critique
Research is still being performed on determining, specifying and modifying trajectories
Source needs copious information about network topology to design a path
Lack of performance comparison to other protocols
Raghav

17. Summary and Conclusions
TBF is an optimized hybrid of Cartesian Forwarding and Source Based Routing
Trades off Communication for Computation
Robust in Adverse Conditions such as Sparse Networks and Imprecise Positioning
Raghav