Preamble detection apparatus, preamble detection method, and program
A preamble detection apparatus includes: a threshold generation unit that determines a correlation maximum value detection threshold on the basis of a correlation peak value; a determination unit that detects one of correlation results, which exceeds the correlation maximum value detection threshold, as a correlation maximum value; a detection unit that updates the correlation peak value to the detected correlation maximum value when the correlation maximum value is detected; and a control unit that sets a period, in the event a correlation peak occurs, to a first period, sets a period, centering on a position where a distance from a correlation peak position is an integer multiple of a frequency hopping cycle, to a second period, and monitors presence or absence of a correlation result that exceeds the correlation maximum value detection threshold in the first and second periods, while not applying an erroneous detection threshold to the first period.
1. A preamble detection apparatus in a wireless communication system which performs frequency hopping, comprising:
a correlation maximum value detection threshold generation unit that determines a correlation maximum value detection threshold on the basis of a correlation peak value;
a correlation maximum value detection determination unit that detects one of correlation results, which exceeds the correlation maximum value detection threshold, as a correlation maximum value;
a correlation peak detection unit that updates the correlation peak value to the detected correlation maximum value when the correlation maximum value is detected by the correlation maximum value detection determination unit; and
a control unit that sets a period, if a correlation peak caused by an LO (Local Oscillator) spurious component occurs, to a first period, sets a period, centering on a position where a distance from a correlation peak position is an integer multiple of a frequency hopping cycle, to a second period, and monitors presence or absence of a correlation result that exceeds the correlation maximum value detection threshold in the first and second periods, while not applying an erroneous detection threshold to the first period.
2. The preamble detection apparatus according to claim 1 , wherein
the first period is a window period centering on a position where a distance from the correlation peak position is an integer multiple of a symbol length other than the integer multiple of the frequency hopping cycle.
3. The preamble detection apparatus according to claim 1 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.
4. The preamble detection apparatus according to claim 2 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.
5. The preamble detection apparatus according to claim 1 , wherein
the correlation maximum value detection threshold generation unit sets the correlation maximum value multiplied by a predetermined coefficient to the correlation maximum value detection threshold.
6. The preamble detection apparatus according to claim 5 , wherein
the predetermined coefficient is not less than one.
7. The preamble detection apparatus according to claim 1 , wherein
when a first detected correlation peak is an undesired correlation peak, the preamble detection apparatus detects that the correlation result which exceeds the correlation maximum value detection threshold is present in the first period or the second period, and updates the first detected correlation peak by a correlation peak corresponding to the correlation result to start over preamble detection processing; and
when the first detected correlation peak is a desired correlation peak, the preamble detection apparatus detects that the correlation result which exceeds the correlation maximum value detection threshold is not present in the first period, and continues the preamble detection processing without updating the correlation peak.
8. A preamble detection method in a wireless communication system that performs frequency hopping, comprising:
determining a correlation maximum value detection threshold on the basis of a correlation peak value;
detecting one of correlation results, which exceeds the correlation maximum value detection threshold, as a correlation maximum value;
updating the correlation peak value to the detected correlation maximum value when the correlation maximum value is detected;
setting a period, in the event if a correlation peak caused by an LO (Local Oscillator) spurious component occurs, to a first period, and setting a period, centering on a position where a distance from a correlation peak position is an integer multiple of a frequency hopping cycle, to a second period; and
monitoring presence or absence of a correlation result that exceeds the correlation maximum value detection threshold in the first and second periods, while not applying an erroneous detection threshold to the first period.
9. The preamble detection method according to claim 8 , wherein
the first period is a window period centering on a position where a distance from the correlation peak position is an integer multiple of a symbol length other than the integer multiple of the frequency hopping cycle.
10. The preamble detection method according to claim 8 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.
11. The preamble detection apparatus according to claim 9 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.
12. A non-transitory computer readable storage medium having machine instructions stored therein, the instructions being executable by one or more computers to cause the one or more computers to perform operations comprising:
determining a correlation maximum value detection threshold on the basis of a correlation peak value;
detecting one of correlation results, which exceeds the correlation maximum value detection threshold, as a correlation maximum value;
updating the correlation peak value to the detected correlation maximum value when the correlation maximum value is detected;
setting a period, if a correlation peak caused by an LO (Local Oscillator) spurious component occurs, to a first period, and setting a period, centering on a position where a distance from a correlation peak position is an integer multiple of a frequency hopping cycle, to a second period; and
monitoring presence or absence of a correlation result that exceeds the correlation maximum value detection threshold in the first and second periods, while not applying an erroneous detection threshold to the first period.
13. The non-transitory computer readable storage medium according to claim 12 , wherein
the first period is a window period centering on a position where a distance from the correlation peak position is an integer multiple of a symbol length other than the integer multiple of the frequency hopping cycle.
14. The non-transitory computer readable storage medium according to claim 12 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.
15. The non-transitory computer readable storage medium according to claim 13 , wherein
the second period is a window period centering on the position where the distance from the correlation peak position is the integer multiple of the frequency hopping cycle.