Can i listen peripheral instead of scan?

[leo.ni]

Hi,all. i use iPhone6 to scan peripherals around.As this,power consume great.Can i listen peripheral instead? Is it save power?Thanks a lot!

[Susheel Nuguru]

what do you mean by scan peripherals and listen peripherals? what is the difference?

[David Edwin]

The scanner can do passive scanning as opposed to active scanning to reduce power consumption. However I am certain that iOS only uses active scanning. Active scanning means sending out SCAN_REQ while passive scanning means listening to the Advertisement packets being received.

[Susheel Nuguru]

Edwin. I knew about active and passive scanning, got confused by the terminology he used.

Leo, There is not much difference in terms of power in active and passing scanning, for both scanner and advertiser(which is sending scan response) For any type of scanning, the Radio will be ON for the fixed time. Scanner will be only RX for passive and RX/TX for active. This will happen only within the scan window. Looking at the data sheet, it is not a huge difference in power for this two. What matters most is the scan window size. If you look at the product sheet

[leo.ni]

Thanks a lot! My phone is a center device,how to save power for it?

[Susheel Nuguru]

try to minimize scan window. You should balance this depending on the advertisement interval. You scan window cannot be too small and for power efficiency it cannot be too long.

It is difficult to come up with some number, of how much it should be , but the central examples in SDK are using 100ms scan interval and 50 ms scan window. So the scanner will be on 50% of the time. You can also use something like this!!?