Monday, June 19, 2017

WiFi: Load balancing through probe response control

Basic Idea:
Clients use probe requests as one of the first frames before connecting to an access point (AP). If the AP does not respond with a probe-response frame, the client will not proceed with the connection. We leverage this condition to control how clients are distributed across multiple access points in the network. This approach to client - balancing has the advantage that:
1. Load both RF and CPU are balanced across the APs.
2. No disconnect/connect is required for load balancing.
3. Leverages the fact that typical WLAN mobility is pseudo-static. So clients will not move significantly from the places where they connect. Even in case of mobility, the disruption is minimal.

Patent abstract:
System and methods are provided for dynamically setting a threshold signal-to-noise ratio for probe requests for one or more access points in a wireless network based on several factors, including density/distance between access points and/or current and expected load on access points. By dynamically adjusting a threshold signal-to-noise for probe requests, the systems and methods described herein may efficiently utilize resources based on current and/or expected conditions. In particular, an access point may ignore client device probe requests when another access point may be better positioned to handle such a request and/or when the access point would be unable to meet expected load requirements if such an associate were made.

Citation information:
Gautam D Bhanage, Parthasarathy Narasimhan, "Automatic calibration of probe request received signal strength indication (RSSI) threshold to control associations", US Patent 9,408,181, Year 2016.

Bibtex Citation information:
  title={Automatic calibration of probe request received signal strength indication (RSSI) threshold to control associations},
  author={Bhanage, Gautam D and Narasimhan, Parthasarathy},
  month=aug # "~2",
  note={US Patent 9,408,181}