Pre-phase error correction transmitter

• US 20050105598A1
• Filed: 12/27/2004
• Published: 05/19/2005
• Est. Priority Date: 03/28/2000
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Kaewell, John D.
• Granted Patent: US 7,519,103 B2
• Time in Patent Office: Days
• 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. A base station for transmitting and receiving communication signals, comprising a receiver and transmitter, the receiver including:

an antenna for receiving a communication signal, the communication signal including a plurality of individual channels;

an adaptive matched filter for filtering said received signal to generate a filtered signal using a weighting signal; and

an analyzer for analyzing said received signal for errors and generating a correction signal based on said analysis, and said analyzer further includes;

at least one despreader for despreading said filtered signal using a pilot signal, and providing a despread filtered signal;

a processor for performing a hard decision on said despread filtered signal and generating symbol outputs therefrom; and

an error correction generator circuit to generate said correction signal; and

a correction unit for correcting said received signal at the symbol level by using said correction signal, said correction removing a phase error from said despread filtered signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for each multipath component of said received signal; and

a mixer for mixing said path values with said correction signal to generate said weighting signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for a plurality of multipath components of said received signal;

the analyzer providing correction signals for each of said plurality of multipath components; and

a mixer for mixing said path values with plural ones of said correction signals to generate said weighting signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for each of a predetermined plurality of multipath components of said received signal;

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

a mixer for mixing said path values with plural ones of said correction signals to generate said weighting signal.

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

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

7. The base station of claim 1 wherein said 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 said 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 for transmitting and receiving a communication signal, comprising a receiver and transmitter, the receiver including:

an antenna for receiving a communication signal, the communication signal including a plurality of individual channels;

an adaptive matched filter for filtering said received signal to generate a filtered signal using a weighting signal; and

an analyzer for analyzing said received signal for errors and generating a correction signal for a subset of said individual channels based on said analysis, and said analyzer further includes;

at least one despreader for despreading said filtered signal using a pilot signal, and providing a despread filtered signal;

a processor for performing a hard decision on said despread filtered signal and generating symbol outputs therefrom; and

an error correction generator circuit to generate said correction signal;

a correction unit for correcting said received signal at the symbol level by using said correction signal, said correction removing a phase error from said despread filtered signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for each multipath component of said received signal; and

a mixer for mixing said path values with said correction signal to generate said weighting signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for a plurality of multipath components of said received signal;

the analyzer providing correction signals for each of said plurality of multipath components; and

a mixer for mixing said path values with plural ones of said correction signal to generate said weighting signal.

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

a RAKE receiver for demodulating said received signal and generating relative path values for each of a predetermined plurality of multipath components of said received signal;

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

a mixer for mixing said path values with plural ones of said correction signals to generate said weighting signal.

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

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

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