Identification of start and end points of transmitted data in spread spectrum communication systems
First Claim
1. A spread spectrum communication method comprising the steps of:
- correlating a received signal with a spread code;
comparing a correlative output, obtained in said correlating step, to a reference value; and
recognizing a start point of information transmission in a case where the correlative output becomes lower than the reference value, after being higher than the reference value on the basis of a comparison result obtained at said comparing step.
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Abstract
A spread spectrum communication apparatus receives a preamble signal or a postamble signal as a pilot signal, and applies a correlative demodulation by using a single spread signal to the pilot signal, and a correlative output obtained after the correlative demodulation is compared to a reference value. If the correlative output is equal to or greater than the reference value, then it is recognized as a preamble or postamble signal. In accordance with a trailing edge of the preamble signal or a leading edge of the postamble signal, a start point or an end point of information transmission can be recognized, respectively, in a lower level of a communication system without using a unique word in a data stream, thereby reducing overhead of an upper level protocol and improving data transmission efficiency.
33 Citations
22 Claims
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1. A spread spectrum communication method comprising the steps of:
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correlating a received signal with a spread code; comparing a correlative output, obtained in said correlating step, to a reference value; and recognizing a start point of information transmission in a case where the correlative output becomes lower than the reference value, after being higher than the reference value on the basis of a comparison result obtained at said comparing step. - View Dependent Claims (2, 3)
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4. A spread spectrum communication method comprising the steps of:
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correlating a received signal with a spread code; comparing a correlative output, obtained in said correlating step, to a reference value; and recognizing an end point of information transmission in a case where the correlative output becomes more than the reference value, after being lower than the reference value, on the basis of a comparison result obtained at said comparing step. - View Dependent Claims (5, 6)
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7. A spread spectrum communication apparatus comprising:
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correlating means for generating a correlative output corresponding to a correlation between a received signal and a spread code; comparing means for comparing the correlative output to a reference value; and recognition means for recognizing a start point of information transmission in a case where the correlative output becomes lower than the reference value, after being higher than the reference value, on the basis of a comparison result by said comparing means. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A spread spectrum communication apparatus comprising:
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correlating means for generating a correlative output corresponding to a correlation between a received signal and a spread code; comparing means for comparing the correlative output to a reference value; and recognition means for recognizing an end point of information transmission in a case where the correlative output becomes more than the reference value, after being lower than the reference values, on the basis of a comparison result by said comparing means. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A spread spectrum communication apparatus comprising:
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correlative demodulation means for performing correlative demodulation on a received signal by using a single spread code; comparing means for comparing a correlative output from said correlative demodulation means to a reference value; recognition means for recognizing either a start point or an end point of information transmission on the basis of a comparison result by said comparing means; generating means for generating a synchronization signal when a received signal and a code are synchronized; and latching means for latching the synchronization signal in accordance with the comparison result by said comparing means.
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22. A spread spectrum communication apparatus comprising:
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correlative demodulation means for performing correlative demodulation on a received signal by using a single spread code; comparing means for comparing a correlative output from said correlative demodulation means to a reference value; recognition means for recognizing either a start point or an end point of information transmission on the basis of a comparison result by said comparing means; generating means for generating a carrier wave recovery establishment signal when a carrier wave of a received signal is recovered; and latching means for latching the carrier wave recovery establishment signal in accordance with the comparison result by said comparing means.
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Specification