1. 1 Introduction to Wireless Networks Michalis Faloutsos

2. 2 Topics Of Interest The capacity of ad hoc networks What is the inherent capacity of a network Characterizing the topology Mobility and its effect Mobility models Characterizing the topology of mobility pattern The effect of power-range Simulating TCP over ad hoc networks Simulating multicasting in ad hoc networks

3. 3 We need to model contention First the obvious Adjacent edges Second, one edge away, considering RTS CTS Third, interference (500m instead of 250m) Modeling issue

4. 4 Typical “Errors” Mobility: too slow or too fast Mobility speed may not be the expected Homogeneity may “hide” issues Few nodes are responsible for most traffic Some spots are more popular than others Power range is too large for the area Ie radius 250m, a grid of 1Km -> one broadcast covers “half” the area

5. 5 What’s the problem? There is no systematic way to model and simulate such networks No clue what are the right assumptions Not sure how the assumptions affect the results

6. 6 Consequences Simulation results are Meaningless Unrepeatable Incomparable between different analysis Prone to manipulation Claim: give me any statement, I can create simulations to prove it

7. 7 What Will We Do Here? Identify assumptions Some of them are subtle Characterize the scenarios Study their effect on the performance results