Capacity Allocation in Wireless LANs

Godfrey Tan, John Guttag
MIT LCS Technical Report, MIT-LCS-TR-973

Today's access point based wireless LANs (WLANs) are inefficient and unfair. For many traffic loads they provide far less total throughput than they should, and do a poor job allocating what throughput they do deliver. Inappropriate association of nodes to access points and rates to flows plays a large role in these problems. We address a major root cause of this problem in this paper.

Current practice ignores the distinction between flows that connect two wireless nodes via an access point and flows that connect wireless nodes to the wired infrastructure. As wireless devices and applications become more pervasive, ignoring this distinction will lead to a significant degradation in perceived performance.

In this paper, we i) describe a series of examples that illustrates the impact of two-hop flows on the performance of the system, ii) provide a practical algorithm to solve the AP-assignment problem and iii) evaluate the performance of our algorithm against other approaches. Our preliminary results show that our algorithm can increase average achieved throughput by as much as 50% for some traffic loads.

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Bibtex Entry:

   author =       "Godfrey Tan and John Guttag",
   title =        "{Capacity Allocation in Wireless LANs}", 
   institution =  {MIT CSAIL},
   year =         {2004},
   month =        {November},
   number =       {973},
   address =      {Cambridge, MA}