Pre-phase error correction transmitter

• US 7,519,103 B2
• Filed: 12/27/2004
• Issued: 04/14/2009
• Est. Priority Date: 03/28/2000
• Status: Expired due to Term

• 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:
  US11/022,722
• Publication Number:
  US 20050105598A1
• Time in Patent Office: 1,569 Days
• Field of Search: 375/141, 375/130, 375/147, 375/150, 375/296, 375/326, 455/24, 455/69, 370/342, 370/325, 370/335
• US Class Current: 375/141
• 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. A base station comprising a receiver and transmitter, the receiver including:

an antenna configured to receive a communication signal, the communication signal including a plurality of individual channels;

an adaptive matched filter configured to filter the received signal and generate a filtered signal using a weighting signal;

an analyzer configured to analyze the received signal for errors and generate a correction signal based on the analysis, the analyzer further including;

at least one despreader configured to despread said filtered signal using a pilot signal, and provide a despread filtered signal;

a processor configured to perform a hard decision on the despread filtered signal and generate symbol outputs therefrom; and

an error correction generator circuit configured to generate the correction signal; and

a correction unit configured to correct the received signal at a symbol level by using the correction signal, whereby the correction of the received signal removes a phase error from the despread filtered signal.

2. The base station of claim 1 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for each multipath component of the received signal; and

a mixer configured to mix the path values with the correction signal to generate the weighting signal.

3. The base station of claim 1 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for a plurality of multipath components of the received signal;

the analyzer further configured to provide correction signals for each of the plurality of multipath components; and

a mixer configured to mix the path values with the correction signal to generate the weighting signal.

4. The base station of claim 1 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for each of a predetermined plurality of multipath components of the received signal;

a separate analyzer for each of the plurality of multipath components; and

a mixer configured to mix the path values with the correction signal to generate the weighting signal.

5. The base station of claim 1 wherein the plurality of individual channels have different data rates.

6. The base station of claim 1 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication.

7. The base station of claim 1 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication on separate channels, the data rates selected based upon a type of signal.

8. The base station of claim 1 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication on separate channels, the data rates selected based upon at least one of a type of signal, or in response to a set data rate.

9. A mobile station comprising a receiver and transmitter, the receiver including:

an antenna configured to receive a communication signal, the communication signal including a plurality of individual channels;

an adaptive matched filter configured to filter the received signal and generate a filtered signal using a weighting signal;

an analyzer configured to analyze said received signal for errors and generate a correction signal for a subset of the individual channels based on the analysis, said analyzer further including;

at least one despreader configured to despread the filtered signal using a pilot signal, and provide a despread filtered signal;

a processor configured to perform a hard decision on the despread filtered signal and generate symbol outputs therefrom; and

an error correction generator circuit configured to generate the correction signal; and

a correction unit configured to correct the received signal at a symbol level by using the correction signal, whereby the correction of the received signal removes a phase error from the despread filtered signal.

10. The mobile station of claim 9 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for each multipath component of the received signal; and

a mixer configured to mix the path values with the correction signal to generate said weighting signal.

11. The mobile station of claim 9 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for a plurality of multipath components of the received signal;

the analyzer configured to provide correction signals for each of the plurality of multipath components; and

a mixer configured to mix the path values with the correction signal to generate the weighting signal.

12. The mobile station of claim 9 wherein the correction unit comprises:

a RAKE receiver configured to demodulate the received signal and generate relative path values for each of a predetermined plurality of multipath components of the received signal;

a separate analyzer for each of the plurality of multipath components; and

a mixer configured to mix the path values with the correction signal to generate the weighting signal.

13. The mobile station of claim 9 wherein the plurality of individual channels have different data rates.

14. The mobile station of claim 9 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication on separate channels.

15. The mobile station of claim 9 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication on separate channels, data rate selected based upon a type of signal.

16. The mobile station of claim 9 wherein the plurality of individual channels have different data rates and provide voice and nonvoice communication on separate channels, data rate selected based upon at least one of a type of signal, or in response to a set data rate.