7. Conclusion
IEEE 802.11 based WLANs are an important part of the future wireless Internet. Understanding their performance is crucial in order to gain an insight into the different system tradeoffs involved. In this paper, we have built a mathematical model that allows to study the tradeoff between the number of HOs and the total system rate for a set of IEEE 802.11 based access points, that are connected to the Internet. Our model is built on a MILP with the objective of both maximizing the total download rate while at the same time minimizing the number of HOs with a configurable HO signaling rate. Because the objective function is composed of two conflicting terms, we have studied the tradeoff between the two objectives in the optimization function, which allowed us to find a good compromise between download rate and number of HOs. An important aspect of our model is the total knowledge of all system parameters over the whole simulation duration, which is typically not known in advance. As future work, we intend to apply robust optimization techniques on our model in order to cope with unknown or erroneous predicted demands, mobility patterns and download rates. By applying robust optimization techniques we expect to get better insight into the tradeoffs involved when the exact values of several parameters of the system are not precisely known. Also, we intend to study fast heuristics that can be applied when some parameters of the system changes in order to react fast during critical situations.
