Wideband code-division multiple access system and method

• US 5,909,435 A
• Filed: 02/12/1998
• Issued: 06/01/1999
• Est. Priority Date: 08/27/1996
• Status: Expired due to Fees

• Current Assignee: Transsky Corporation
• Original Assignee: Transsky Corporation
• Inventors: Apelewicz, Tuvia
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): Tran, Maikhanh
• Application Number:
  US09/022,831
• Time in Patent Office: 474 Days
• Field of Search: 370/342, 370/320, 370/335, 375/200, 375/326, 375/349, 375/205, 375/206, 375/229, 375/235
• US Class Current: 370/342
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence

Abstract

A wideband code division multiple access, spread-spectrum communications system, having an equalization channel. The transmitter transmits data over a spread-spectrum channel, along with a spread-spectrum channel having little or no information, i.e., an equalization channel. The receiver uses in-phase early, punctual and late signals, and quadrature-phase early, punctual and late signals, for equalizing of the data spread-spectrum channel, and for generating an output in-phase data signal and an output quadrature-phase data signal.

Claims

1. An improvement to a wideband code-division-multiple-access (W-CDMA) system, comprising:

a W-CDMA transmitter, said W-CDMA transmitter including,

an in-phase-data-product device for multiplying an in-phase-data (IDATA) signal with a data-chip-sequence signal, thereby generating an IDATA-spread-spectrum signal;

a quadrature-phase-data-product device for multiplying a quadrature-phase-data (QDATA) signal with the data-chip-sequence signal, thereby generating a QDATA-spread-spectrum signal;

equalization-chip means for outputting an equalization-chip-sequence signal;

an in-phase combiner, coupled to said in-phase-data-product device and to said equalization-chip means, for linearly combining the IDATA-spread-spectrum signal and the equalization-chip-sequence signal, to generate an in-phase-combined-spread-spectrum signal;

a quadrature-phase combiner, coupled to said quadrature-phase-data-product device and to said equalization-chip means, for linearly combining the QDATA-spread-spectrum signal, and the equalization-chip-sequence signal, to generate the quadrature-phase-combined-spread-spectrum signal;

a quadrature-phase-shift-keyed (QPSK) modulator, coupled to said in-phase combiner and to said quadrature-phase combiner, for QPSK modulating the in-phase-combined-spread-spectrum signal with the quadrature-phase-combined-spread-spectrum signal, thereby generating a QPSK-spread-spectrum signal;

a power amplifier, coupled to said QPSK modulator, for amplifying the QPSK-spread-spectrum signal;

a transmitter antenna, coupled to said power amplifier, for radiating the amplified QPSK-spread-spectrum signal over a communications channel;

a W-CDMA receiver, said W-CDMA receiver including,

a receiver antenna for coupling the W-CDMA receiver to the communications channel;

in-phase-equalization means for despreading, at a first chip time and at a second chip time, an in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

quadrature-phase-equalization means for despreading, at the first chip time and at the second chip time, a quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

in-phase-data means for despreading, at the first chip time and at the second chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

quadrature-phase-data means for despreading, at the first chip time and at the second chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

a processor, coupled to said in-phase-equalization means, said quadrature-phase-equalization means, said in-phase-data means, and said quadrature-phase-data means, for determining, from the despread signals, an output-in-phase-data signal and an output-quadrature-phase-data signal.

2. A method using a wideband code-division-multiple-access (W-CDMA) transmitter and a W-CDMA receiver, comprising the steps of:

multiplying, at said W-CDMA transmitter, an in-phase-data (IDATA) signal with a data-chip-sequence signal, thereby generating an IDATA-spread-spectrum signal;

multiplying, at said W-CDMA transmitter, a quadrature-phase-data (QDATA) signal with the data-chip-sequence signal, thereby generating a QDATA-spread-spectrum signal;

generating, at said W-CDMA transmitter, an equalization-chip-sequence signal;

combining, linearly, at said W-CDMA transmitter, the IDATA-spread-spectrum signal and the equalization-chip-sequence signal, to generate an in-phase-combined-spread-spectrum signal;

combining, linearly, at said W-CDMA transmitter, the QDATA-spread-spectrum signal, and the equalization-chip-sequence signal, to generate the quadrature-phase-combined-spread-spectrum signal;

QPSK modulating, at said W-CDMA transmitter, the in-phase-combined-spread-spectrum signal with the quadrature-phase-combined-spread-spectrum signal, thereby generating a QPSK-spread-spectrum signal;

radiating, at said W-CDMA transmitter, the QPSK-spread-spectrum signal over a communications channel;

despreading, at a first chip time, an in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading at a second chip time, the second chip time different from the first chip time, the in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, a quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

generating, from the despread signals, an output-in-phase-data signal and an output-quadrature-phase-data signal.

3. The W-CDMA method as set forth in claim 2, further comprising the steps of:

despreading, at a third chip time, the third chip time different from the first chip time and from the second chip time, the in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

generating, from the despread signals, the output-in-phase-data signal and the output-quadrature-phase-data signal.

8. The W-CDMA method as set forth in claim 2 or 6, wherein the second chip time is later than the first chip time.

9. The W-CDMA method as set forth in claim 2 or 6, wherein the second chip time is earlier than the first chip time.

10. The W-CDMA method as set forth in claim 3 or 7, wherein the second chip time is later than the first chip time and the third chip time is earlier than the first chip time.

4. An improvement to a wideband code-division-multiple-access (W-CDMA) receiver for receiving a QPSK-spread-spectrum signal comprising an in-phase-combined-spread-spectrum signal and a quadrature-phase-combined-spread-spectrum signal, with the in-phase-combined-spread-spectrum signal including an equalization-chip-sequence signal combined with an in-phase-data signal spread-spectrum processed with a data-chip-sequence signal, and with the quadrature-phase-combined-spread-spectrum signal including an equalization-chip-sequence signal combined with a quadrature-phase-data signal spread-spectrum processed with the data-chip-sequence signal, the improvement comprising:

in-phase-equalization means for despreading, at a first chip time and at a second chip time, an in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

quadrature-phase-equalization means for despreading, at the first chip time and at the second chip time, a quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

in-phase-data means for despreading, at the first chip time and at the second chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

quadrature-phase-data means for despreading, at the first chip time and at the second chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

a processor, coupled to said in-phase-equalization means, said quadrature-phase-equalization means, said in-phase-data means, and said quadrature-phase-data means, for determining, from the despread signals, an output-in-phase-data signal and an output-quadrature-phase-data signal.

5. The improvement to the W-CDMA receiver as set forth in claim 4, wherein

said in-phase-equalization means for despreading the in-phase component of the equalization-chip-sequence signal at the first chip time, at the second chip time, and at a third chip time, the first chip time different from the second chip time and from the third chip time, and the second chip time different from the third chip time;

said quadrature-phase-equalization means for despreading the quadrature-phase component of the equalization-chip-sequence signal at the first chip time and at the second chip time and at the third chip time;

said in-phase-data means for despreading the IDATA spread-spectrum signal at the first chip time and at the second chip time and at the third chip time; and

said quadrature-phase-data means for despreading the QDATA spread-spectrum signal at the first chip time and at the second chip time and at the third chip time.

6. A method for improving a wideband code-division-multiple-access (W-CDMA) receiver for receiving a QPSK-spread-spectrum signal comprising an in-phase-combined-spread-spectrum signal and a quadrature-phase-combined-spread-spectrum signal, with the in-phase-combined-spread-spectrum signal including an equalization-chip-sequence signal combined with an in-phase-data signal spread-spectrum processed with a data-chip-sequence signal, and with the quadrature-phase-combined-spread-spectrum signal including an equalization-chip-sequence signal combined with a quadrature-phase-data signal spread-spectrum processed with the data-chip-sequence signal, comprising the steps of:

despreading, at a first chip time, an in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at a second chip time, the second chip time different from the first chip time, the in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, a quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the first chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the second chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

generating, from the despread signals, an output-in-phase-data signal and an output-quadrature-phase-data signal.

7. The W-CDMA method as set forth in claim 6, further comprising the steps of:

despreading, at a third chip time, the third chip time different from the first chip time and from the second chip time, the in-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the quadrature-phase component of the equalization-chip-sequence signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the IDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal;

despreading, at the third chip time, the QDATA spread-spectrum signal embedded in the QPSK-spread-spectrum signal; and

generating, from the despread signals, the output-in-phase-data signal and the output-quadrature-phase-data signal.