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 code, the code produced by binary addition of a first sequence produced by a first feedback shift register with a second sequence produced by a second feedback shift register;
combining the code with encoded message data, producing spread data; and
transmitting the spread data as a quadrature modulated signal.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system. A first long code and a second long code, with each long code having a length of N chips, are generated. The first long code is different from the second long code. The first long code and the second long code are transmitted 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-phase acquisition circuit and a Q-phase acquisition circuit may acquire, in parallel, the first long code and the second long code from the I-phase angle and the Q-phase angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, the first long code and the second long code.
133 Citations
8 Claims
-
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 code, the code produced by binary addition of a first sequence produced by a first feedback shift register with a second sequence produced by a second feedback shift register;
combining the code 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)
-
-
2. The method of clam 1 wherein the quadrature modulated signal is a quadrature phase shift keying signal.
Specification