Can a single BLE central connect with multiple BLE peripherals via bluetooth low energy?

Question

I am using core bluetooth framework in my iOS application project. I have following questions regarding bluetooth low energy-

1. Is it possible for a single central to connect multiple peripherals in iOS?
2. Can multiple central device connect with a single peripheral?
3. Can a single iOS device act as central as well as peripheral at the same time?
4. If yes, then what will happen if both of 2 such devices try to connect as central to each other?
5. Can we communicate via BLE when the app is in background?

Sanchez

Answer 1

Is it possible for a single central to connect multiple peripherals in iOS?

Yes.

Can multiple central device connect with a single peripheral?

That completely depends on whether the peripheral supports it (but for most common embedded devices, no).

Can a single iOS device act as central as well as peripheral at the same time?

Yes.

If yes, then what will happen if both of 2 such devices try to connect as central to each other?

They'll generally connect twice. In one connection, one will be central and one will be peripheral. In the other connection, the reverse. This is a pretty unusual way to design a system, but it is legal will often work, despite being illegal (see Youssif's comment below for reference).

Can we communicate via BLE when the app is in background?

Yes, within various restrictions.

Thornton

Good answer. The only comment I have is regarding 2 devices connecting as both central and peripheral. While yes, in many cases they'll connect twice as you stated, it is technically illegal to do so according to the Bluetooth spec. This is stated in Bluetooth Specification v5.0, Vol 6, Part B, Section 4.5:- "There shall be only one connection between two LE device addresses. An initiator shall not send a connection request to an advertiser it is already connected to. If an advertiser receives a connection request from an initiator it is already connected to, it shall ignore that request" – Delate

Answer 2

1. Yes, it's possible to connect one Central to multiple Peripherals.
2. Not confirmed.
   But single Peripheral can connect only with one Central device and multiple Peripherals can connect with one Central.
   It means that Central can communicate with multiple Peripherals at the same time.
3. Yes, a single iOS device can work both as Central and Peripheral at the same time.
4. It communicates one by one.
5. Yes, we can communicate via BLE in background mode in iOS device.

Inebriant