Tuesday, December 22, 2015

WiFi: What is beacon bursting? What are the tradeoffs?

Beacon bursting is a mechanism by which beacon frames for all the BSSs (Virtual APs) running on that radio are sent out one after the other instead of spreading them out equally in time over the beacon interval. The other approach to sending beacons is to spread them out equally over the beacon interval.

For example, consider the beacon interval is 100msec and you have 5 VAPs beaconing, then, with bursting all the beacons are sent back to back after the beacon interrupt. However, if you are not using bursting, beacons are spread across the 100msecs. Hence, every 20msec the radio will send out the beacon of a different VAP.

Wednesday, December 2, 2015

WiFi: Comparison of WiFi Direct vs WiFi Aware vs BLE vs Adhoc mode (802.11)

WiFi Aware - service discovery that helps setup WiFi Direct links.
BLE - service discovery and P2P connection.
WiFi Direct - P2P connection
WiFi Adhoc mode - basic P2P connection (legacy mechanism)

We will now differentiate between each of these protocol suites and their applications.

WiFi Aware vs BLE
- WiFi Aware has a longer range (because of wifi power limits)
- works with existing WiFi chips (protocol overlay - Phy is mostly the same)
- higher bandwidth than BLE (faster for gaming etc) - this is because it will use WiFi Direct once wifi aware discovers the service.

- WiFi aware works across brands of phone vs ibeacons which will work only on iPhones for e.g.