Online estimation of RF interference

ABSTRACT

Increased AP density in enterprise WLANs leads to increasing RF interference and decreasing performance. An important step towards mitigating this problem is to construct precise RF maps in the form of a conflict graph. Prior work on conflict graph construction, mostly using bandwidth tests [17], suffers from two problems: a) It is limited to static settings and cannot support mobility, and b) It incurs significant measurement overhead and must be performed offline (e.g. overnight). An alternative to bandwidth tests is "micro-probing" [4] that operates on millisecond-level time scales. Micro-probing rapidly constructs the conflict graph even while the network is in use (i.e. online). While interesting in principle, micro-probing has only been evaluated in simulation. In this work, we empirically study micro-probing on a 40-node wireless testbed. In doing so, we not only show that micro-probing is in fact practically realizable, but also present key insights that drive the design choices for our implementation. We benchmark micro-probing against bandwidth tests and find that micro-probing is just as accurate but with up to a 400 times reduction in overhead. Finally, we argue that a successful implementation of micro-probing opens up the space for further innovations in real-time WLAN adaptation and optimization.

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INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.3 SPECIAL-PURPOSE AND APPLICATION-BASED SYSTEMS
      Subjects: Signal processing systems

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.0 General
          Subjects: Data communications
      C.2.1 Network Architecture and Design
          Subjects: Wireless communication

General Terms:
Algorithms, Design, Experimentation, Measurement, Performance