Concurrent multistandard detection receiver with prepacket transmission detection
A concurrent multistandard detection receiver with prepacket transmission detection capabilities is disclosed. In one aspect, a receiver is configured to switch between two different wireless protocols, alternately listening for incoming messages on one then the other protocol. For at least one listening period, the receiver uses two pretransmission detectors that are configured to detect predictable pretransmission emissions. A third detector may detect traditional transmissions. On detection of a signal that matches a predictable pretransmission emission or a traditional transmission, the receiver confirms that an incoming signal according to that standard is being received and acts in accordance with that signal. If no such emission or transmission was received, or if after trying to confirm the presence of an incoming signal fails, the receiver switches back to listening according to the other protocol.
1. An Internet of Things (IoT) device comprising:
a receiver comprising:
a first detector configured to detect, within a predefined time slot, a packet in an incoming signal through correlation with a known preamble;
a second detector configured to detect prepacket emissions through constant wave detection in the incoming signal; and
a control circuit coupled to the first detector and the second detector, the control circuit configured to:
conclude that a constant wave signal is present if an output of the second detector indicates that a detected signal exceeds a threshold; and
responsive to concluding that the constant wave signal is present, extend a time period in which the first detector is allowed to detect a packet preamble; and
a transmitter.
2. The IoT device of claim 1 , wherein the second detector comprises a delay circuit and a correlation circuit that correlates an input signal with a delay output of the delay circuit.
3. The IoT device of claim 2 , wherein the second detector comprises an accumulator circuit coupled to the correlation circuit.
4. The IoT device of claim 3 , wherein the second detector comprises a magnitude circuit coupled to the accumulator circuit.
5. The IoT device of claim 4 , wherein the second detector comprises a comparator coupled to the accumulator circuit, wherein the comparator compares the threshold to an output from the magnitude circuit.
6. The IoT device of claim 1 , further comprising a third detector coupled to the control circuit, the third detector configured to detect leakage transmission.
7. The IoT device of claim 6 , wherein the third detector comprises a short-term averaging circuit and a long-term averaging circuit configured to provide a short-term average and a long-term average of the incoming signal.
8. The IoT device of claim 7 , wherein the third detector comprises a subtraction circuit configured to subtract the long-term average from the short-term average.
9. The IoT device of claim 8 , wherein the third detector comprises a comparator coupled to the subtraction circuit and configured to compare an output of the comparator to the threshold.
10. The IoT device of claim 1 , wherein the control circuit is configured to switch between a first mode using the first detector and the second detector to detect a signal operating in a first wireless protocol and a second mode wherein the receiver is configured to detect a signal operating in a second wireless protocol.
11. A method of detecting incoming messages in a multistandard environment, the method comprising:
detecting within a predefined time slot, with a first detector, a packet in an incoming signal through correlation with a known preamble;
detecting, with a second detector, emissions through constant wave detection in the incoming signal;
concluding that a constant wave signal is present when an output of the second detector indicates that a detected signal exceeds a threshold; and
responsive to concluding that the constant wave signal is present, extending a time period in which the first detector is allowed to detect a packet preamble.
12. The method of claim 11 , wherein detecting with the second detector comprises delaying the incoming signal to create a delay output signal; and
correlating the incoming signal with a delay output signal.
13. The method of claim 12 , wherein detecting with the second detector further comprises accumulating after correlating.
14. The method of claim 13 , wherein detecting with the second detector further comprises determining a magnitude after accumulating.
15. The method of claim 14 , wherein detecting with the second detector further comprises a comparing an accumulated signal to the threshold.
16. A method of detecting incoming messages in a multistandard environment, the method comprising:
detecting within a predefined time slot, with a first detector, a packet in an incoming signal through correlation with a known preamble;
detecting, with a second detector, prepacket emissions through leakage transmission detection in the incoming signal;
concluding that a leakage transmission is present when an output of the second detector indicates that a detected signal exceeds a threshold; and
responsive to concluding that the leakage transmission is present, extending a time period in which the first detector is allowed to detect a packet preamble.
17. The method of claim 16 , wherein detecting with the second detector comprises short-term averaging and long-term averaging circuit the incoming signal.
18. The method of claim 17 , wherein detecting with the second detector further comprises subtracting a long-term average from a short-term average.
19. The method of claim 17 , wherein the concluding comprises comparing an output of a comparator to the threshold.
20. The method of claim 16 , further comprising activating the second detector responsive to detecting an increase in signal strength with the first detector.