System for using rapid acquisition spreading codes for spread-spectrum communications
First Claim
1. A method for transmitting data from a base station to a subscriber unit in a code division multiple access communication system, the method comprising:
- producing a first code, the first code produced by a linear feedback shift register circuit, the linear feedback shift register circuit having a total of thirty six stages;
combining the first code with a short code to produce a spreading sequence, the short code shorter than the first code;
combining the spreading sequence with encoded message data, producing spread data; and
transmitting the spread data as a quadrature modulated signal.
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Accused Products
Abstract
A system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system, comprises a generator for generating a first long code and a second long code, with each long code having a length of N chips. The first long code is different from the second long code. A transmitter transmits the first long code and the second long code at a first phase angle and at a second phase angle, respectively, on a carrier signal over a communications channel using radio waves. The first long code and the second long code may be transmitted at an in-phase (I) angle and at a quadrature-phase (Q) angle, respectively, on the carrier signal. From the communications channel, an I acquisition circuit and a Q acquisition circuit may acquire, in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips of the first long code and the second long code.
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Citations
8 Claims
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1. A method for transmitting data from a base station to a subscriber unit in a code division multiple access communication system, the method comprising:
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producing a first code, the first code produced by a linear feedback shift register circuit, the linear feedback shift register circuit having a total of thirty six stages;
combining the first code with a short code to produce a spreading sequence, the short code shorter than the first code;
combining the spreading sequence with encoded message data, producing spread data; and
transmitting the spread data as a quadrature modulated signal. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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2. The method of clam 1 wherein the quadrature modulated signal is a quadrature phase shift keying signal.
Specification