Distributed vs consolidated advertising

[jeffdev3]

My primary goal is connection success rate and my secondary goal is a fast connection time.  Which advertising method is better: Advertise with a long interval and long window or with short interval and short window?  Is it generally true that if the total time spent advertising is equivalent, the connection success rate is equivalent?  For example I have 2 sets of advertising parameters:

Set 1 - Interval=100s, window=20s

Set 2 - Interval=10s, window=2s

After 100s, is the connection success rate roughly equivalent under both sets?  The peripheral is the nRF and the central is a cell phone so the scan parameters are not fixed but for analysis I am assuming scan parameters are fixed.  Can anyone provide equations for calculating the connection success rate given total time spent advertising, advertising interval/window, and scan interval/window?  I am assuming if the scan window overlaps with the advertising window, the connection will be successful.  Thank you.

[Sigurd]

Hi,

It's the scanner that uses scan interval and window. The advertiser only uses a interval.

[jeffdev3]

Let me correct my terminology for advertising.

Set 1 - Interval=100ms, period=100s, duration=20s

Set 2 - Interval=100ms, period=10s, duration=2s

Set 1 advertises for 20s with 100ms interval every 100s and set 2 advertises for 2s with 100ms interval every 10s.  The total advertising packets sent after 100s is equivalent but is it safe to assume the connection success rate is also equivalent?

[Sigurd]

So for set 1, the device starts up, and you need to scan and connect within 20 seconds, if you are not connecting within 20 seconds, you need to wait 80 seconds before you can try again. That's quite a long time.
Set 2, device starts up, if you are not connecting within the 2 seconds, you need to wait 8 seconds before you can try again.

My primary goal is connection success rate

1) What's your definition of "connection success rate"? 

2) Is is a human that needs to connect, or is the scanning& connection initiation automated?

[jeffdev3]

Connection success rate is the probability that the central receives one advertisement given a total advertising duration.  I assume the rest of the connection procedure will be successful after an advertisement is received.  The central is a phone with an app that automatically starts scanning whenever it is not connected.  I am looking for some equations to calculate the probability similar to the ones in this paper:

www.scirp.org/.../paperinformation.aspx

[Sigurd]

Hi,

I see. I don't have equations for this, but I would assume you need to know the scan interval/window of the scanner, or make some assumption on how it behaves, to compare the 2 adverting sets in that case.