Method and system for transmitting and receiving signals transmitted from an antenna array with transmit diversity techniques

• US 6,317,411 B1
• Filed: 02/22/1999
• Issued: 11/13/2001
• Est. Priority Date: 02/22/1999
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kuchi, Kiran Kumar, Whinnett, Nicholas William, Boixadera, Francesc, Rohani, Kamyar, Clop, Oscar
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Elallam, Ahmed
• Application Number:
  US09/253,786
• Time in Patent Office: 995 Days
• Field of Search: 370/335, 370/342, 370/204, 370/441, 370/479, 375/200, 375/267, 375/299
• US Class Current: 370/204
• CPC Class Codes: H04B 7/0604 with predefined switching scheme
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

In a method for wireless data communication between a base station and a subscriber unit in a wireless communication system, groups of symbols of an input data stream are commutated to produce a plurality of commutated data streams. The plurality of commutated data streams are then transformed to produce a plurality of transformed data streams. Next, each transformed data stream is spread with a selected one of a plurality of spreading codes to produce a plurality of antenna signals. Finally, each of the plurality of antenna signals is transmitted using a selected one of a plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity. In one embodiment, the transform is a space-time transform.

Claims

1. A method for transmitting data from a transmitter to a receiver in a wireless communication system, wherein the transmitter uses an antenna array to transmit a signal having transmit diversity, the method comprising the steps of:

commutating groups of symbols of an input data stream to produce first and a second commutated data streams;

space-time coding the first commutated data stream to produce first and second transformed data streams;

space-time coding the second commutated data stream to produce third and fourth transformed data streams;

spreading each transformed data stream with a selected one of a plurality of spreading codes to produce a plurality of antenna signals; and

transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

2. The method for transmitting data according to claim 1 wherein the step of commutating groups of symbols of an input data stream to produce a plurality of commutated data streams further includes:

selecting an N-symbol group of an input data stream, where N is greater than or equal to 1;

outputting the N-symbol group at a first commutator output to produce the first commutated data stream;

selecting a second N-symbol group of the input data stream; and

outputting the second N-symbol group at a second commutator output to produce the second commutated data stream.

3. The method for transmitting data according to claim 1 wherein the step of space-time coding a first commutated data stream to produce first and second transformed data streams further includes:

in response to an input of the first commutated data stream having symbols S₁S₁S₂S₂, outputting, during a first period, symbols S₁S₁ from a first transform output, and outputting a negative complex conjugate of symbols S₂S₂ from a second transform output; and

outputting, during a second period, symbols S₂S₂ from the first transform output, and outputting a complex conjugate of symbols S₁S₁ from the second transform output.

4. The method for transmitting data according to claim 1 wherein the step of transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas further includes modulating, upconverting, amplifying, and transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

5. The method for transmitting data according to claim 1 wherein the step of transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas further includes selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals.

6. The method for transmitting data according to claim 5 wherein the step of periodically selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals further includes periodically selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals according to an antenna switching pattern that is synchronized with a symbol clock divided by an integer.

7. A system for transmitting data from a transmitter to a receiver in a wireless communication system, wherein the transmitter uses an antenna array to transmit a signal having transmit diversity, the system comprising:

a commutator for commutating groups of symbols of an input data stream to produce first and a second commutated data streams;

a first space-time coder for space-time coding the first commutated data stream to produce first and second transformed data streams;

a second space-time coder for space-time coding the second commutated data stream to produce third and fourth transformed data streams;

spreaders for spreading each transformed data stream with a selected one of a plurality of spreading codes to produce a plurality of antenna signals; and

transmitters for transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

8. The system for transmitting data according to claim 7 wherein the commutator for commutating groups of symbols of an input data stream to produce a plurality of commutated data streams further includes:

means for selecting an N-symbol group of an input data stream, where N is greater than or equal to 1;

means for outputting the N-symbol group at a first commutator output to produce the first commutated data stream;

means for selecting a second N-symbol group of the input data stream; and

means for outputting the second N-symbol group at a second commutator output to produce the second commutated data stream.

9. The system for transmitting data according to claim 7 wherein the first space-time coder for space-time coding a first commutated data stream to produce first and second transformed data streams further includes:

means for outputting, during a first period, symbols S₁S₁ from a first transform output, and outputting a negative complex conjugate of symbols S₂S₂ from a second transform output in response to an input of the first commutated data stream having symbols S₁S₁S₂S₂; and

means for outputting, during a second period, symbols S₂S₂ from the first transform output, and outputting a complex conjugate of symbols S₁S₁ from the second transform output.

10. The system for transmitting data according to claim 7 wherein the transmitters for transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas further include means for modulating, upconverting, amplifying, and transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

11. The system for transmitting data according to claim 7 wherein the transmitters for transmitting each of the plurality of antenna signals using a selected one of a plurality of spaced apart antennas further include means for selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals.

12. The system for transmitting data according to claim 11 wherein the means for selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals further includes means for periodically selecting different antennas in the antenna array for transmitting each of the plurality of antenna signals according to an antenna switching pattern that is synchronized with a symbol clock divided by an integer.

13. A method for receiving data in a receiver in a wireless communication system, wherein the data has been transmitted from a transmitter using an antenna array to transmit a signal having transmit diversity, the method comprising the steps of:

receiving and down-converting a received signal to produce a baseband received signal;

despreading the baseband received signal using despreading codes that correspond to spreading codes used in the transmitter to produce antenna signals that are transmitted from antennas in the antenna array, wherein the despreading produces received transformed signals;

space-time decoding each received transformed signal to produce inverse transformer output signals; and

de-commutating all inverse transformer output signals to produce a signal containing traffic channel data.

14. The method for receiving data according to claim 13 wherein the step of de-commutating all inverse transformer output signals to produce a signal containing traffic channel data further includes:

selecting and outputting a first group of symbols from a first inverse transformer output signals during a first period;

selecting and outputting a second group of symbols from a second inverse transformer output signals during a second period to produce a signal containing traffic channel data.

15. The method for receiving data according to claim 13 wherein the step of space-time decoding each received transformed signal to produce inverse transformer output signals further includes estimating two symbols using coherently combined channel gains to produce inverse transformer output signals.

16. A system for receiving data in a receiver in a wireless communication system, wherein the data has been transmitted from a transmitter using an antenna array to transmit a signal having transmit diversity, the system comprising:

a receiver for receiving and down-converting a received signal to produce a baseband received signal;

despreaders for despreading the baseband received signal using despreading codes that correspond to spreading codes used in the transmitter to produce antenna signals that are transmitted from antennas in the antenna array, wherein the despreading produces received transformed signals;

space-time decoders for space-time decoding each received transformed signal to produce inverse transformer output signals; and

a de-commutator for de-commutating all inverse transformer output signals to produce a signal containing traffic channel data.

17. The system for receiving data according to claim 16 wherein the de-commutator for de-commutating all inverse transformer output signals to produce a signal containing traffic channel data further includes:

means for selecting and outputting a first group of symbols from a first inverse transformer output signals during a first period;

means for selecting and outputting a second group of symbols from a second inverse transformer output signals during a second period to produce a signal containing traffic channel data.

18. The system for receiving data according to claim 16 wherein the space-time decoders for space-time decoding each received transformed signal to produce inverse transformer output signals further include means for estimating two symbols using coherently combined channel gains to produce inverse transformer output signals.

19. A method for transmitting data from a transmitter to a receiver in a wireless communication system, wherein the transmitter uses an antenna array to transmit a signal having transmit diversity, the method comprising the steps of:

space-time coding groups of symbols of an input data stream to produce first and second transformed data streams;

spreading each transformed data stream with a same spreading code to produce a plurality of antenna signals;

selecting one of a plurality of space apart antennas from the antenna array for each one of the plurality of antenna signals, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity; and

transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas.

20. The method for transmitting data according to claim 19 wherein the step of space-time coding a group of symbols of an input data stream to produce first and second transformed data streams further includes:

in response to an input data stream having symbols S₁S₂, outputting, during a first period, symbol S₁ from a first transform output, and outputting a negative complex conjugate of symbol S₂ from a second transform output; and

outputting, during a second period, symbol S₂ from the first transform output, and outputting a complex conjugate of symbol S₁ from the second transform output, wherein the first and second transform outputs output first and second transformed data streams.

21. The method for transmitting data according to claim 19 wherein the step of spreading each transformed data stream with a spreading code to produce a plurality of antenna signals further includes spreading each transformed data stream with a same spreading code to produce a plurality of antenna signals.

22. The method for transmitting data according to claim 19 wherein the step of selecting one of a plurality of spaced apart antennas from the antenna array for each one of the plurality of antenna signals further includes periodically selecting N number of a plurality of X number of spaced apart antennas in the antenna array for each of N number of antenna signals, wherein N is an integer greater than or equal to 2, and X is an integer greater than or equal to 1.

23. The method for transmitting data according to claim 19 wherein the step of transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas further includes modulating, upconverting, amplifying, and transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

24. A system for transmitting data from a transmitter to a receiver in a wireless communication system, wherein the transmitter uses an antenna array to transmit a signal having transmit diversity, the system comprising:

a space-time coder for space-time coding groups of symbols of an input data stream to produce first and second transformed data streams;

spreaders for spreading each transformed data stream with a same spreading code to produce a plurality of antenna signals;

means for selecting one of a plurality of spaced apart antennas from the antenna array for each one of the plurality of antenna signals, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity; and

a transmitter for transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas.

25. The system for transmitting data according to claim 24 wherein the space-time coder for space-time coding a group of symbols of an input data stream to produce first and second transformed data streams further includes:

means for outputting, during a first period, symbol S₁ from a first transform output, and outputting a negative complex conjugate of symbol S₂ from a second transform output in response to an input data stream having symbols S₁S₂; and

means for outputting, during a second period, symbol S₂ from the first transform output, and outputting a complex conjugate of symbol S₁ from the second transform output, wherein the first and second transform outputs output first and second transformed data streams.

26. The system for transmitting data according to claim 24 wherein the spreaders for spreading each transformed data stream with a spreading code to produce a plurality of antenna signals further includes spreaders for spreading each transformed data stream with a same spreading code to produce a plurality of antenna signals.

27. The system for transmitting data according to claim 24 wherein the means for selecting one of a plurality of spaced apart antennas from the antenna array for each one of the plurality of antenna signals further includes means for periodically selecting N number of a plurality of X number of spaced apart antennas in the antenna array for each of N number of antenna signals, wherein N is an integer greater than or equal to 2, and X is an integer greater than or equal to 1.

28. The system for transmitting data according to claim 24 wherein the transmitters for transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas further includes means for modulating, upconverting, amplifying, and transmitting each of the plurality of antenna signals from the selected one of the plurality of spaced apart antennas, wherein the plurality of spaced apart antennas are spaced apart to provide transmit diversity.

29. A method for receiving data in a receiver in a wireless communication system, wherein the data has been transmitted from a transmitter using selected antennas in an antenna array for selected time periods to transmit a signal having different channels in response to the selected antennas in the selected time periods, the method comprising the steps of:

receiving and down-converting a received signal to produce a baseband received signal;

despreading the baseband received signal using a despread code that corresponds to a spreading code used in the transmitter to produce a plurality of antenna signals that are transmitted from selected antennas in the antenna array, each antenna in the antenna array utilizing a same spreading code, wherein the despreading produces received transformed signals; and

in response to the channel determined by the selected antennas in the selected time period, space-time decoding each received transformed signal to produce inverse transformed output signals.

30. A system for receiving data in a receiver ina wireless communication system, wherein the data has been transmitted from a transmitter using selected antennas in an antenna array for selected time periods to transmit a signal having different channels in response to the selected antennas in the selected time periods, the system comprising:

a receiver for receiving and down-converting a received signal to produce a baseband received signal;

a despreader for despreading the baseband received signal using a despreading code that corresponds to a spreading code used in the transmitter to produce a plurality of antenna signals that are transmitted from selected antennas utilizing a same spreading code for each antenna in the antenna array, wherein the despreading produces received transformed signals; and

an inverse transformer for inverse transforming each received transformed signal to produce inverse transformer output signals in response to the channel determined by the selected antennas in the selected time period.