Apple Inc.
Low power, low latency, high duty cycle scan for Bluetooth Low Energy

Abstract:

A system, method and apparatus for simultaneously minimizing power and latency in a scan for advertisement packets from one or more peripheral devices in a Bluetooth Low Energy (BLE) frequency band having a number of advertisement channels. A receiver front end receives BLE signals, and a local oscillator (LO) generator has an output frequency that is sequentially tuned to a frequency of each of the advertisement channels. An energy detector monitors signal energy on each of the advertisement channels in sequence, and when the signal energy exceeds a threshold, fixes the output frequency of the LO generator to that advertisement channel. An automatic gain controller controls a gain of the signal on the one of the plurality of advertisement channels to generate a controlled gain signal, and a correlator correlates the controlled gain signal with an advertisement packet on the one of the advertisement channels.