Scheme for spread spectrum multiple access coding
First Claim
1. A method comprising:
- generating a plurality of pulses having polarity and a plurality of different time intervals between successive pulses;
generating a plurality of codewords from the plurality of pulses using the polarity of each pulse;
generating codewords such that a cross-correlation between any two codewords in the plurality of codewords has side lobes that have the values of zero, positive amplitude squared, and minus amplitude squared;
generating codewords that have a zero correlation window in an auto-correlation function; and
wherein the cross-correlation function has a magnitude equal to the amplitude squared and wherein a width of the zero correlation window equals to two times the shortest interval of the plurality of intervals.
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Abstract
This invention publishes a spread spectrum multiple access coding technique applied in any wireless digital telecommunication system involving Code Division Multiple Access and spread spectrum technique. The group of basic pulses has normalized amplitudes and duration of 1 and polarity; the number of basic pulses is ascertained by practical factors; there is no equal interval between basic pulses on time axis, and asymmetry of pulses'"'"' positions is employed to achieve arranging coding. This coding scheme can control and minimize the side lobes of auto-correlation and cross-correlation functions, then simplify the design of a CDMA system, so a wireless digital telecommunication system with large capacity can be established effectively to solve the contradiction between ever increasing demand for telecommunication capacity and limited frequency resources.
25 Citations
15 Claims
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1. A method comprising:
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generating a plurality of pulses having polarity and a plurality of different time intervals between successive pulses;
generating a plurality of codewords from the plurality of pulses using the polarity of each pulse;
generating codewords such that a cross-correlation between any two codewords in the plurality of codewords has side lobes that have the values of zero, positive amplitude squared, and minus amplitude squared;
generating codewords that have a zero correlation window in an auto-correlation function; and
wherein the cross-correlation function has a magnitude equal to the amplitude squared and wherein a width of the zero correlation window equals to two times the shortest interval of the plurality of intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method comprising:
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generating a plurality of pulses having polarity and a plurality of different time intervals between successive pulses;
generating a plurality of codewords from the plurality of pulses using the polarity of each pulse, and spread-spectrum processing each pulse by a pulse compression code.
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15. A method comprising:
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generating a plurality of pulses having polarity and a plurality of different time intervals between successive pulses;
spread-spectrum processing each pulse by a pulse compression code;
generating a plurality of codewords from the plurality of pulses using the polarity of each pulse; and
time off-setting and overlapping each said codeword in the plurality of codewords.
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Specification