Blind detection and synchronization of data packets
A method and receiver are disclosed for the blind detection and synchronization of data packets are disclosed. According to one aspect, a method includes generating a running histogram of received sample values for each of a plurality of frequency bins and symbol timing phases, the running histogram spanning a most recent block of symbols representing a candidate synchronization (sync) word. The method also includes, for each symbol interval: analyzing the histogram to estimate symbol timing phase, DC offset and frequency offset. The method also includes determining a first candidate sync word based at least in part on the symbol timing phase, frequency offset and corresponding DC offset the first candidate sync word representing a most recent vector of bits associated with the first candidate sync word. The method further includes discerning a lower address part (LAP) obtained from the first candidate sync word to enable detection of a packet.
1. A method for blind detection of a lower address part (LAP) of data packets received by a receiver, the method comprising:
extracting binary vectors from a received signal;
for each binary vector:
extracting a synchronization (sync) word from the binary vector;
determining a lower address part (LAP) based on the sync word; and
when the sync word satisfies at least one predetermined criterion, outputting the LAP and declaring a detected packet.
2. The method of claim 1 , further comprising:
encoding a first candidate sync word, the encoded sync word being based on the LAP; and
comparing the encoded sync word to the first candidate sync word, the at least one predetermined criterion being a match between the encoded sync word and the extracted sync word within a distance of a specified number of bit errors, t.
3. The method of claim 2 , wherein the first candidate sync word is based at least in part on at least one of a symbol timing phase, a DC offset, and a frequency offset.
4. The method of claim 1 , further comprising:
decoding the extracted sync word to a closest discernible codeword, the at least one predetermined criterion being discernment of the codeword.
5. The method of claim 1 , further comprising:
encoding the sync word; and
comparing the encoded sync word with the extracted sync word, the at least one predetermined criterion being a match between the encoded sync word and the extracted sync word within a distance of a specified number of bit errors, t.
6. The method of claim 1 , wherein each binary vector is evaluated to determine a resemblance to a Classic Bluetooth compatible sync word within an error allowance of a specified number of bit errors, t.
7. The method of claim 1 , further comprising:
determining a histogram of an extracted binary vector;
performing a symbol template correlation based at least in part on the histogram; and
determining a frequency offset and a corresponding DC offset of the binary vector based at least in part on the template correlation.
8. The method of claim 7 , wherein the symbol template is based on an eye diagram, the eye diagram being based on a symbol rate and a symbol duration.
9. The method of claim 8 , wherein when the eye diagram has an eye a presence of a Bluetooth-compliant packet is declared.
10. The method of claim 7 , wherein the histogram has a size that is based on a number of samples per symbol and a number of frequency bins in the histogram.
11. A receiver configured for blind detection of a lower address part (LAP) of received data packets, the receiver having processing circuitry configured to:
extract binary vectors from a received signal;
for each binary vector:
extract a synchronization (sync) word from the binary vector;
determine a lower address part (LAP) based on the sync word; and
when the sync word satisfies at least one predetermined criterion, output the LAP and declare a detected packet.
12. The receiver of claim 11 , wherein the processing circuitry is further configured to:
encode a first candidate sync word, the encoded sync word being based on the LAP; and
compare the encoded sync word to the first candidate sync word, the at least one predetermined criterion being a match between the encoded sync word and the extracted sync word within a distance of a specified number of bit errors, t.
13. The receiver of claim 12 , wherein the first candidate sync word is based at least in part on at least one of a symbol timing phase, a DC offset, and a frequency offset.
14. The receiver of claim 11 , wherein the processing circuitry is further configured to:
decode the extracted sync word to a closest discernible codeword, the at least one predetermined criterion being discernment of the codeword.
15. The receiver of claim 11 , wherein the processing circuitry is further configured to:
encode the sync word; and
compare the encoded sync word with the extracted sync word, the at least one predetermined criterion being a match between the encoded sync word and the extracted sync word within a distance of a specified number of bit errors, t.
16. The receiver of claim 11 , wherein each binary vector is evaluated to determine a resemblance to a Classic Bluetooth compatible sync word within an error allowance of a specified number of bit errors, t.
17. The receiver of claim 11 , wherein the processing circuitry is further configured to:
determine a histogram of an extracted binary vector;
perform a symbol template correlation based at least in part on the histogram; and
determine a frequency offset and a corresponding DC offset of the binary vector based at least in part on the template correlation.
18. The receiver of claim 17 , wherein the symbol template is based on an eye diagram, the eye diagram being based on a symbol rate and a symbol duration.
19. The receiver of claim 18 , wherein when the eye diagram has an eye a presence of a Bluetooth-compliant packet is declared.
20. The receiver of claim 17 , wherein the histogram has a size that is based on a number of samples per symbol and a number of frequency bins in the histogram.