Does Bluetooth low energy feature a piconet as in classic BT?

Yes. A 'peripheral' device ( or slave) can have ONLY ONE 'central' device (or master). A central device can connect to many peripheral devices. Classic BT is limited to 7 peripherals because devices have a 3-bit address. BLE uses a 24-bit address, theoretically allowing millions of slave devices in a star configuration. In reality, hundreds of slave devices is more practical since each connection needs radio time and RAM. For example, with 100 slave connections each slave will only have the attention of the master for 10 ms in each second on average.

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