Manchester encoded on-off keying transmissions for wake-up protocol
In an embodiment, an apparatus includes a baseband processor comprising: a packet generation circuit to generate a wake-up packet comprising information to cause a first receiver to trigger a wake-up of a second receiver; an encoder to encode the wake-up packet with Manchester encoding to output Manchester encoded on-off keying (MOOK) data; and a modulator coupled to the encoder to receive random data and modulate the random data. This modulated random data may be amplitude modulated with the MOOK data to realize a radio frequency (RF) signal comprising the MOOK data that is to be transmitted to one or more receivers.
1 . An apparatus comprising:
a random number generator to generate random data;
a baseband processor comprising:
a packet generation circuit to generate a wake-up packet, the packet generation circuit to generate the wake-up packet comprising information to cause a first receiver to trigger a wake-up of a second receiver;
an encoder to encode the wake-up packet with Manchester encoding to output Manchester encoded on-off keying (MOOK) data; and
a modulator coupled to the encoder to receive the random data and modulate the random data;
a digital-to-analog converter (DAC) coupled to the baseband processor to convert the modulated random data to an analog stream;
a mixer coupled to the DAC to upconvert the analog stream to a radio frequency (RF) signal;
a power amplifier coupled to the mixer, the power amplifier to amplitude modulate the RF signal with the MOOK data and output an amplified RF signal; and
wherein the packet generation circuit is to generate the wake-up packet comprising a preamble and a sync word, wherein the first receiver is to detect the wake-up packet and acquire a timing synchronization based at least in part on the preamble and the sync word.
2 . The apparatus of claim 1 , wherein the modulator is to modulate the random data according to a Bluetooth protocol.
3 . The apparatus of claim 1 , wherein the packet generation circuit is to generate the wake-up packet comprising a variable length packet having a length dependent upon a payload.
4 . The apparatus of claim 1 , wherein the packet generation circuit is to generate the wake-up packet comprising an address field having address information to identify at least the first receiver.
5 . The apparatus of claim 4 , wherein the packet generation circuit is to generate the wake-up packet comprising the address field having the address information comprising a first portion to identify a group and a second portion to identify the first receiver.
6 . A system comprising:
a first radio to receive and process an incoming radio frequency (RF) signal comprising a Manchester encoded on-off keying (MOOK) packet, the first radio comprising:
an analog front end circuit to process the incoming RF signal into a lower frequency signal, the analog front end circuit comprising:
a peak detector to detect a peak signal in the lower frequency signal;
a comparator to compare the peak signal to a threshold value, the comparator to output a comparison signal based on the comparison; and
a digitizer to digitize the comparison signal into a bit stream; and
a digital circuit coupled to the analog front end circuit to receive the bit stream, the digital circuit comprising:
a scheduler to enable a core circuit for a scan window according to a predetermined interval; and
the core circuit coupled to the scheduler to process the MOOK packet during the scan window; and
a second radio coupled to the first radio, wherein in response to detection of the MOOK packet comprising a wake-up packet, the first radio is to send a wake-up signal to the second radio.
7 . The system of claim 6 , wherein the analog front end circuit further comprises a filter circuit coupled to the comparator to provide the threshold value to the comparator.
8 . The system of claim 7 , wherein the digital circuit is to send a signal to cause the threshold value to be reset when a blocker signal is detected.
9 . The system of claim 6 , wherein the digital circuit further comprises:
a first correlator to receive at least a first portion of the bit stream and perform a correlation on the first portion to identify a first portion of a sync word of a wake-up packet; and
a second correlator to receive at least a second portion of the bit stream and perform a correlation on the second portion to identify a second portion of the sync word of the wake-up packet, wherein the second correlator is to be enabled when a result of the correlation on the first portion exceeds a first threshold.
10 . The system of claim 9 , wherein the digital circuit further comprises an averager circuit to decode another portion of the sync word.
11 . The system of claim 10 , wherein the averager circuit is to decode the wake-up packet and send the wake-up signal in response to detection of the wake-up packet.