I'm trying to find out the best timings for a complex bluetooth low energy (BLE) system, where a central station shall be able to connect to smartphones (=scanner) as well as to coin-cell powered BLE-tags (=advertiser). I.e. the central station must play dual roles, scanner and advertiser.
The overall timings (central station ADV-interval, Scan-interval, Scan-window; BLE-tag ADV-interval) must be selected to ensure best performance (fast device discovery) as well as low power consumption.
I could calculate and simulate best match of scan and advertising parameters, but everything depends on the scan settings of the smartphones, which I don't know.
[I know about Apple's Accessory Design Guidelines listing some preferred advertising intervals, but that's just a little part of the puzzle - e.g. it's not possible to determine the (max) discovery time.]
Does anybody know the SCAN behavior (scan-interval, scan-window) on the smartphone are?
For various power modes (low-power background scanning, active, etc.)?
For the various Smartphone types (Apple, Android)?
Can you provide links to specifications?
For this topic abouut BLE Scan Interval user4028 commented with a few info links. Thanks a lot.
Unfortunately my simulation results for 30ms/300ms scanning do not match Apples list of preferred advertising intervals.
The charts (blue=average, orange=maximum) show discovery times (y-axis) depending on advertising interval (x-axis) for a scan-interval of 300ms and scan-window of 30ms, simulated with 20000 random start times for each point. The minima show useful ADV-intervals. (The simulation tool is a self-made Excel-VBA, I have created in my job, so unfortunately I cannot make it public.)