Pre-phase error correction

• US 8,798,116 B2
• Filed: 07/15/2013
• Issued: 08/05/2014
• Est. Priority Date: 03/28/2000
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Kaewell, John D.
• Primary Examiner(s): Tran, Khai
• Application Number:
  US13/942,015
• Publication Number:
  US 20130301684A1
• Time in Patent Office: 386 Days
• Field of Search: 375/147, 375/130, 375/141, 375/221, 375/285, 375/296, 375/326, 375/377, 455/24, 455/69
• US Class Current: 375/147
• CPC Class Codes: H04B 1/62 for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 1/7097 Interference-related aspects
• CPC Class Codes: H04B 1/711 the interference being multi-path interference
• CPC Class Codes: H04B 2001/70724 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/696 relating to Dowlink
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04L 2027/0022 using the carrier of the associated receiver of a transceiver
• CPC Class Codes: H04L 27/20 Modulator circuits; Transmitter circuits

Abstract

A CDMA communication system includes a signal processor which encodes voice and nonvoice signals into data at various rates, e.g. data rates of 8 kbps, 16 kbps, 32 kbps, or 64 kbps as I and Q signals. The signal processor selects a specific data rate depending upon the type of signal, or in response to a set data rate. When the signal is received and demodulated, the baseband signal is at the chip level. Both the I and Q components of the signal are despread using the conjugate of the pn sequence used during spreading, returning the signal to the symbol level. Carrier offset correction is performed at the symbol level. A lower overall processing speed is therefore required.

Claims

1. An integrated circuit (IC), comprising:

circuitry configured to receive a radio frequency signal;

wherein the circuitry is further configured to despread a plurality of data signals and to despread a pilot signal from the radio frequency signal;

wherein a phase of each of the data signals was adjusted prior to transmission; and

circuitry configured to derive a correction signal, the correction signal including weights to adjust the phase of the data signals, and to output the correction signal for sending to a base station so that the phase of the data signals are adjusted in response to the correction signal.

2. The IC of claim 1 wherein the correction signal is derived from the pilot signal.

3. The IC of claim 1 wherein the data signals only include data.

4. The IC of claim 1 wherein each of the plurality of data signals is received over an in-phase and a quadrature carrier of the radio frequency signal.

5. The IC of claim 1 wherein the pilot signal is a QPSK signal.

6. The IC of claim 1 wherein each of the data signals is a QPSK signal.

7. An integrated circuit (IC), comprising:

circuitry configured to adjust a phase of a plurality of spread data signals in response to a correction signal, the correction signal including weights to adjust the phase of the data signals;

wherein the correction signal was received from a mobile device;

wherein the circuitry is further configured to output for transmission the plurality of phase adjusted data signals to the mobile station and to output for transmission a spread pilot signal.

8. The IC of claim 7 wherein each of the plurality of data signals is transmitted over an in-phase and a quadrature carrier of a radio frequency signal.

9. The IC of claim 7 wherein the pilot signal is a QPSK signal.

10. The IC of claim 7 wherein each of the data signals is a QPSK signal.

11. The IC of claim 7 wherein the spread data signals only include data.

12. A wireless communication system including at least one mobile user device and at least one base station, comprising:

the mobile user device comprising;

a receiver configured to receive a radio frequency signal;

wherein the receiver is further configured to despread a plurality of data signals and to despread a pilot signal from the radio frequency signal;

wherein a phase of each of the data signals was adjusted prior to transmission; and

wherein the mobile user device is configured to derive a correction signal, the correction signal including weights to adjust the phase of the data signals, and to send the correction signal to the base station so that the phase of the data signals are adjusted in response to the correction signal; and

the base station comprising;

a transmitter to adjust a phase of a plurality of spread data signals in response to the correction signal, the correction signal including the weights to adjust the phase of the data signals;

wherein the correction signal was received from the mobile device;

wherein the transmitter is further configured to transmit the plurality of phase adjusted data signals to the mobile station and to transmit a spread pilot signal.

13. The system of claim 12 wherein the correction signal is derived from the pilot signal.

14. The system of claim 12 wherein the data signals only include data.

15. The system of claim 12 wherein each of the plurality of data signals is received over an in-phase and a quadrature carrier of the radio frequency signal.

16. The system of claim 12 wherein the pilot signal is a QPSK signal.

17. The system of claim 12 wherein each of the data signals is a QPSK signal.