Joint packet detection in a wireless communication system with one or more receivers
A packet detector joint detects 802.11a packets, 802.11b packets and interference that is within a monitored frequency range but is not formatted as 802.11a packets or 802.11b packets. The packet detector can use signals from one or more antennas. Detection of signals is done using differentially detected correlations. In addition to packet detection, the packet detector can identify signal levels, noise levels and locations of narrowband interference. The process of packet detection and identifying other indicators can be done simultaneously and as the signal is being received.
1. A packet detector for detecting data packets of a first format and a second format, the packet detector comprising:
inputs from a plurality of antennas configured to receive different signals, the inputs coupled to an analysis circuit, a first subsection, and a second subsection;
wherein the analysis circuit is configured to determine, for the different signals received from the inputs, that a data packet is present in at least one of the first format or the second format in response to a ratio of a moving sum of a maximum of differential correlations of the different signals to a moving sum of power levels of the different signals meeting a predetermined condition.
2. The packet detector of claim 1 , wherein the analysis circuit comprises:
a correlation circuit configured to determine a correlation metric relating to the first format; and
power measuring means configured to indicate the power levels of the different signals received over the plurality of antennas.
3. The packet detector of claim 1 , further comprising a detector output configured to, based upon the ratio of the moving sum of the maximum of the differential correlations to the moving sum of the power levels meeting the predetermined condition, output a signal indicative of a presence of a data packet in the first format or the second format.
4. The packet detector of claim 3 , wherein the first subsection is configured to receive the signal indicating the presence of a data packet in the first format, and based upon receipt of the signal, processes the data packet.
5. The packet detector of claim 3 , wherein the second subsection is configured to receive the signal indicating the presence of a data packet in the second format, and based upon receipt of the signal, processes the data packet.
6. The packet detector of claim 3 , wherein the analysis circuit operates at a single sampling frequency.
7. The packet detector of claim 6 , wherein the single frequency is about 20 MHz.
8. The packet detector of claim 6 , wherein the single frequency is about 22 MHz.
9. The packet detector of claim 1 , wherein the analysis circuit is configured to determine that the data packet is present in the at least one of the first format or the second format in response to the ratio exceeding a predetermined threshold.
10. An apparatus for detecting data packets of a first format and a second format, the packet detector comprising:
means for receiving signals from each of a plurality of antennas for receiving different signals, the means for receiving signals coupled to a means for analyzing the different signals, a first means for processing data packets encoded in a first format, and a second means for processing data packets encoded in a second format; and
the means for analyzing the signals for determining that a data packet is present in the first format or the second format in response to a ratio of a moving sum of a maximum of differential correlations of the different signals to a moving sum of power levels of the different signals meeting a predetermined condition.
11. The packet detector of claim 10 , wherein the means for analyzing comprises:
a correlation circuit for determining a correlation metric relating to the first format; and
power measuring means for indicating the power levels of the different signals received over the plurality of antennas.
12. The apparatus of claim 10 , further comprising means for outputting a signal indicative of a presence of a data packet to the first means for processing data packets encoded in the first format and to the second means for processing data packets encoded in the second format.
13. The packet detector of claim 12 , wherein processing by the first means for processing data packets encoded in the first format is performed in response to the signal from the means for outputting indicating that a data packet is present in the first format.
14. The apparatus of claim 12 , wherein the second means for processing is configured to receive the signal indicating the presence of a data packet in the second format, and based upon receipt of the signal, processes the data packet.
15. The apparatus of claim 10 , wherein the means for analyzing operating at a single sampling frequency.
16. The apparatus of claim 15 , wherein the single frequency is about 20 MHz.
17. The apparatus of claim 15 , wherein the single frequency is about 22 MHz.
18. A computer-readable non-transitory storage medium comprising computer-executable instructions that, in response to execution by a computing system, cause the computing system to perform operations, comprising:
receiving a plurality of signals over a plurality of antennas;
providing the plurality of signals to a first subsection for processing data packets encoded in a first format, to a second subsection for processing data packets encoded in a second format, and to an analysis circuit; and
analyzing the plurality of signals to determine that a data packet is present in either the first format or the second format including determining that a ratio of a moving sum of a maximum of differential correlations of the plurality of signals to a moving sum of power levels of the plurality of signals exceeds a predetermined ratio.
19. The computer-readable non-transitory storage medium of claim 18 , wherein the analyzing the plurality of signals further comprises:
determining a correlation metric relating to the first format; and
measuring the power levels of the plurality of signals.
20. The computer-readable non-transitory storage medium of claim 18 , further comprising, based upon the determining of the ratio of the moving sum of the maximum of the differential correlations to the moving sum of the power levels exceeding the predetermined ratio, sending a signal indicative of a presence of a data packet to the first subsection or the second subsection.
21. The computer-readable non-transitory storage medium of claim 20 , wherein processing by the first subsection is performed in response to the plurality of signals indicating that a data packet is present in the first format.
22. The computer-readable non-transitory storage medium of claim 20 , wherein the second subsection being configured to, based upon receiving the signal indicating the presence of a data packet in the second format, processing the data packet.
23. The computer-readable non-transitory storage medium of claim 18 , wherein analyzing the received signals includes operating at a common frequency.
24. The computer-readable non-transitory storage medium of claim 23 , wherein the common frequency is about 20 MHz.
25. The computer-readable non-transitory storage medium of claim 23 , wherein the common frequency is about 22 MHz.
26. A method for detecting data packets of a first format and a second format, comprising:
receiving a plurality of signals over a plurality of antennas;
providing the plurality of signals to a first subsection for processing data packets encoded in the first format, to a second subsection for processing data packets encoded in the second format, and to an analysis circuit; and
analyzing the plurality of signals including determining that a data packet is present in at least one of the first format or the second format including determining a ratio of a moving sum of a maximum of differential correlations of the plurality of signals to a moving sum of power levels of the plurality of signals exceeds a predetermined ratio.
27. The method of claim 26 , wherein the analysis circuit operates at a single sampling frequency of about 20 MHz.
28. The method of claim 26 , wherein analyzing the received signals comprises:
determining a correlation metric relating to the first format; and
measuring the power levels of the plurality of signals.
29. The method of claim 26 , further comprising, based upon the determining the ratio of the moving sum of the maximum of the differential correlations to the moving sum of the power levels exceeding a predetermined ratio, sending a signal indicative of a presence of a data packet to the first subsection and the second subsection.
30. The method of claim 29 , wherein processing by the first subsection is performed in response to the signal from the detector output indicating the data packet being present in the first format.
31. The method of claim 29 , wherein the second subsection being configured for processing the data packet upon the signal indicating the data packet being encoded in the second format.
32. The method of claim 26 , wherein the analysis circuit operates at a common sampling frequency.
33. The method of claim 26 , wherein the analysis circuit operates at a common sampling frequency of about 22 MHz.