Low-complexity synchronization header detection

Abstract

A technique of separating a sequence of modulation shift keying (MSK) symbols into a first portion and a second portion and separately comparing the first portion of the sequence of MSK symbols and the second portion of the sequence of MSK symbols against a first portion of a reference sequence of MSK symbols and a second portion of the reference sequence of MSK symbols allows a low complexity detection of a start field delimiter in a wireless communication packet.

1 . A system comprising:
 a minimum-shift keying (MSK) demodulation circuit having an input, a first output, and a second output, the MSK demodulation circuit configured to generate a sequence of MSK symbols, output a first portion of the sequence of MSK symbols at the first output of the MSK demodulation circuit, and output a second portion of the sequence of MSK symbols at the second output of the MSK demodulation circuit;   a first qualifier circuit having an input and an output, the input of the first qualifier circuit coupled to the first output of the MSK demodulation circuit, the first qualifier circuit configured to compare the first portion of the sequence of MSK symbols against a first set of reference MSK symbols;   a second qualifier circuit having an input and output, the input of the second qualifier circuit coupled to the second output of the MSK demodulation circuit, the second qualifier circuit configured to compare the second portion of the sequence of MSK symbols against a second set of reference MSK symbols; and   a detector circuit with a first input, a second input, and an output, the first input of the detector circuit coupled to the output of the first qualifier circuit and the second input of the detector circuit coupled to the output of the second qualifier circuit, the detector circuit configured to indicate detection of a start field delimiter at the output of the detector circuit based on the comparison of the first portion of the sequence of MSK symbols against the first set of reference MSK symbols at the first qualifier circuit and the comparison of the second portion of the sequence of MSK symbols against the second set of reference MSK symbols at the second qualifier circuit.   
     
     
         2 . The system of  claim 1 ,
 wherein the sequence of MSK symbols is a sequence of 32 MSK symbols, and   wherein the first portion of each sequence of MSK symbols is a first MSK symbol of the sequence of 32 MSK symbols.   
     
     
         3 . The system of  claim 1 ,
 wherein the sequence of MSK symbols is a sequence of 32 MSK symbols, and   wherein the second portion of the sequence of MSK symbols is a second through 31st MSK symbols of the sequence of 32 MSK symbols.   
     
     
         4 . The system of  claim 1 ,
 wherein the start field delimiter is an IEEE 802.15.4g start field delimiter.   
     
     
         5 . The system of  claim 1 ,
 wherein the first qualifier circuit is configured to compute a Hamming distance between the first portion of the sequence of MSK symbols and the first set of reference MSK symbols, and   wherein the first qualifier module is configured to determine a relationship between the Hamming distance and a first threshold value.   
     
     
         6 . The system of  claim 1 ,
 wherein the second qualifier module is configured to compute a Hamming distance between the second portion of the sequence of MSK symbols and the second set of reference MSK symbols, and   wherein the second qualifier module is configured to determine a relationship between the Hamming distance and a second threshold value.   
     
     
         7 . A receiver comprising:
 a minimum-shift keying (MSK) demodulation circuit having an input, a first output, and a second output, the MSK demodulation circuit configured to generate a sequence of MSK symbols, output a first portion of the sequence of MSK symbols at the first output of the MSK demodulation circuit, and output a second portion of the sequence of MSK symbols at the second output of the MSK demodulation circuit; a microcontroller configured to detect a start field delimiter in the received plurality of MSK symbols, comprising:   a first qualifier circuit having an input and an output, the input of the first qualifier circuit coupled to the first output of the MSK demodulation circuit, the first qualifier circuit configured to compare the first portion of the sequence of MSK symbols against a first set of reference MSK symbols;   a second qualifier circuit having an input and output, the input of the second qualifier circuit coupled to the second output of the MSK demodulation circuit, the second qualifier circuit configured to compare the second portion of the sequence of MSK symbols against a second set of reference MSK symbols; and   a detector circuit with a first input, a second input, and an output, the first input of the detector circuit coupled to the output of the first qualifier circuit and the second input of the detector circuit coupled to the output of the second qualifier circuit, the detector circuit configured to indicate detection of a start field delimiter at the output of the detector circuit based on the comparison of the first portion of the sequence of MSK symbols against the first set of reference MSK symbols at the first qualifier circuit and the comparison of the second portion of the sequence of MSK symbols against the second set of reference MSK symbols at the second qualifier circuit.   
     
     
         8 . The receiver of  claim 7 ,
 wherein the sequence of MSK symbols is a sequence of 32 MSK symbols, and   wherein the first portion of the sequence of MSK symbols is a first MSK symbol of the sequence of 32 MSK symbols.   
     
     
         9 . The receiver of  claim 7 ,
 wherein the sequence of MSK symbols is a sequence of 32 MSK symbols, and   wherein the second portion of the sequence of MSK symbols is a second through 31st MSK symbols of the sequence of 32 MSK symbols.   
     
     
         10 . The receiver of  claim 7 ,
 wherein the start field delimiter is an IEEE 802.15.4g start field delimiter.   
     
     
         11 . The receiver of  claim 7 ,
 wherein the first qualifier circuit is configured to compute a Hamming distance between the first portion of the sequence of MSK symbols and the first set of reference MSK symbols, and   wherein the first qualifier circuit is configured to determine a relationship between the Hamming distance and a first threshold value.   
     
     
         12 . The receiver of  claim 7 ,
 wherein the second qualifier circuit is configured to compute a Hamming distance between the second portion of the sequence of MSK symbols and the second set of references MSK symbols, and   wherein the second qualifier module is configured to determine a relationship between the Hamming distance and a second threshold value.   
     
     
         13 . A method comprising:
 receiving a sequence of minimum-shift keying (MSK) symbols;   comparing a first portion of the sequence of MSK symbols against a first set of reference MSK symbols;   comparing a second portion of the sequence of MSK symbols against a second set of reference MSK symbols; and   detecting a start field delimiter based on the comparison of the first portion of the sequence of MSK symbols against the first set of reference MSK symbols at the first qualifier circuit and the comparison of the second portion of the sequence of MSK symbols against the second set of reference MSK symbols at the second qualifier circuit.   
     
     
         14 . The method of  claim 13 ,
 wherein the sequence of MSK symbols is a sequence of 32 MSK symbols,   wherein the first portion of the sequence of MSK symbols is a first MSK symbol of the sequence of 32 MSK symbols, and   wherein the second portion of the sequence of MSK symbols is a second through 31st MSK symbols of the sequence of 32 MSK symbols.   
     
     
         15 . The method of  claim 13 ,
 wherein the start field delimiter is an IEEE 802.15.4g start field delimiter.   
     
     
         16 . The method of  claim 13 ,
 wherein comparing the first portion of the sequence of MSK symbols against the first set of reference MSK symbols comprises computing a Hamming distance between the first portion of each of the plurality of sequences of MSK symbols and the first portion of each of the plurality of sequences of reference MSK symbolswherein the first comparison indicates a successful match responsive to the Hamming distance having a first relationship with a first threshold value.   
     
     
         17 . The method of  claim 13 ,
 wherein comparing the second portion of the sequence of MSK symbols against the second set of reference MSK symbols comprises computing a Hamming distance between the second portion of each of the plurality of sequences of MSK symbols and the second portion of each of the plurality of sequences of references MSK symbols.   
     
     
         18 . One or more computer-readable non-transitory storage media coupled to one or more processors and embodying software, the processors being operable when executing the software to:
 receive a sequence of minimum-shift keying (MSK) symbols;   compare a first portion of the sequence of MSK symbols against a first set of reference MSK symbols;   compare a second portion of the sequence of MSK symbols against a second set of reference MSK symbols; and   detect a start field delimiter based on the comparison of the first portion of the sequence of MSK symbols against the first set of reference MSK symbols at the first qualifier circuit and the comparison of the second portion of the sequence of MSK symbols against the second set of reference MSK symbols at the second qualifier circuit.   
     
     
         19 . The media of  claim 18 ,
 wherein the start field delimiter is an IEEE 802.15.4g start field delimiter,   wherein the sequence of MSK symbols is a sequence of 32 MSK symbols,   wherein the first portion of the sequence of MSK symbols is a first MSK symbol of the sequence of 32 MSK symbols, and   wherein the second portion of the sequence of MSK symbols is a second through 31st MSK symbols of the sequence of 32 MSK symbols.   
     
     
         20 . The media of  claim 18 ,
 wherein comparing the first portion of the sequence of MSK symbols against the first set of reference MSK symbols comprises computing a first Hamming distance between the first portion of each of the plurality of sequences of MSK symbols and the first portion of each of the plurality of sequences of reference MSK symbols; and   wherein comparing the second portion of the sequence of MSK symbols against the second set of reference MSK symbols comprises computing a second Hamming distance between the second portion of each of the plurality of sequences of MSK symbols and the second portion of each of the plurality of sequences of references MSK symbols.