Data transmission scheme in wireless communication system

• US 20070054633A1
• Filed: 10/12/2005
• Published: 03/08/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Piirainen, Olli
• Granted Patent: US 7,542,734 B2
• Time in Patent Office: Days
• US Class Current: 455/115.300
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0697 using spatial multiplexing

Abstract

The invention provides a data transmission solution in a telecommunication system. According to the invention, a data transmission scheme is selected for a first transceiver unit, which comprises a plurality of transmit antennas, on the basis of the quality of a communication link and transmit antenna correlation information associated with the first transceiver unit, from a list including at least the following data transmission schemes: transmitting different data from each antenna of the first transceiver unit, the data transmitted from one antenna being independent of the data transmitted from another antenna; and transmitting the same data from each antenna of the first transceiver unit and controlling the direction of the transmitted data according to the properties of a radio channel. The selection of the data transmission scheme is carried out during an active communication link between the first and a second transceiver unit.

Claims

1. A data transmission method in a telecommunication system, the method comprising:

selecting, during an active communication link between a first and a second transceiver unit, a data transmission scheme for the first transceiver unit based on a quality of the communication link and transmit antenna correlation information associated with the first transceiver unit, wherein the data transmission scheme is selected from a list including at least one of,

transmitting different data from each antenna of the first transceiver unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the first transceiver unit and controlling direction of the transmitted identical data according to properties of a radio channel.

2. The method of claim 1, further comprising determining, in the second transceiver unit, the quality of the communication link by calculating a signal-to-noise ratio or signal-to-interference-plus-noise ratio of a signal received from the first transceiver unit.

3. The method of claim 1, further comprising:

receiving, in the second transceiver unit, a pilot signal transmitted from the first transceiver unit;

calculating a signal-to-noise ratio and antenna correlation information of the first transceiver unit from the received pilot signal;

selecting the data transmission scheme for the first transceiver unit based on the calculated signal-to-noise ratio and first transceiver unit antenna correlation information; and

transmitting information on the selected data transmission scheme to the first transceiver unit.

4. The method of claim 3, further comprising:

calculating a maximum data transfer capacity for each data transmission scheme based on the calculated signal-to-noise ratio and first transceiver unit antenna correlation information, and

selecting the data transmission scheme resulting in a highest maximum data transfer capacity.

5. The method of claim 4, wherein the calculation of the maximum data transfer capacity for each data transmission scheme includes,

calculating a first transceiver unit antenna covariance matrix from the received pilot signal;

calculating eigenvalue decomposition for the first transceiver unit antenna covariance matrix to obtain an eigenvalue matrix and an eigenvector matrix;

setting eigenvalues equal when calculating the maximum data transfer capacity for the transmission scheme of transmitting different data from each antenna of the first transceiver unit; and

setting all other eigenvalues except an eigenvalue having the largest value, to zero when calculating the maximum data transfer capacity for the transmission scheme of transmitting the same data from each antenna of the first transceiver unit and controlling the direction of the transmitted data according to the properties of a radio channel.

6. The method of claim 1, wherein the data transmission scheme of transmitting different data from each antenna of the first transceiver unit comprises:

allocating different data to be transmitted from each antenna of the first transceiver unit by converting a data stream in a serial form into several data streams in a parallel form with each data stream comprising different data, wherein a number of parallel data streams corresponds to a number of antennas in the first transceiver unit; and

transmitting each parallel data stream through a different antenna.

7. The method of claim 1, further comprising controlling a direction of transmission of the first transceiver unit according to transmit direction information received from the second transceiver unit.

8. The method of claim 1, wherein the data transmission scheme of transmitting the same data from each antenna of the first transceiver unit and controlling the direction of the transmitted data according to the properties of a radio channel includes,

allocating identical data to be transmitted from each antenna of the first transceiver unit by copying a data stream into several data streams, wherein a number of data streams corresponds to a number of antennas in the first transceiver unit;

and

controlling a direction of transmission according to transmit direction information received from the second transceiver unit.

9. The method of claim 7, further comprising:

calculating, in the second transceiver unit, eigenvalue decomposition for the first transceiver unit antenna covariance matrix to obtain an eigenvalue matrix and an eigenvector matrix;

selecting an eigenvector associated with a highest eigenvalue of the eigenvalue matrix;

transmitting the selected eigenvector to the first transceiver unit; and

transmitting, by the first transceiver unit, data into at least one direction indicated by the selected eigenvector.

10. A transceiver unit in a telecommunication system, the transceiver unit comprising:

a communication interface including a plurality of antennas for transmitting and receiving information signals; and

a control unit connected to the communication interface, the control unit being configured to select a data transmission scheme based on data transmission scheme information received from another transceiver unit, and to transmit data through the communication interface according to the selected data transmission scheme, wherein the data transmission scheme is selected from a list including at least one of;

transmitting different data from each antenna of the communication interface, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the communication interface and controlling a direction of the transmitted identical data according to properties of a radio channel.

11. The transceiver unit of claim 10, wherein, upon selecting the data transmission scheme of transmitting different data from each antenna of the communication interface, the control unit is further configured to:

allocate different data to be transmitted from each antenna of the transceiver unit by converting a data stream in a serial form into several data streams in a parallel form with each parallel data stream including different data, wherein a number of lower data-rate data streams corresponds to a number of antennas in the transceiver unit; and

transmit each parallel data stream through a different antenna.

12. The transceiver unit of claim 11, wherein the control unit is further configured to control the direction of transmission of the transceiver unit according to transmit direction information received from the other transceiver unit.

13. The transceiver unit of claim 10, wherein, upon selecting the transmission scheme of transmitting the same data from each antenna of the communication interface and controlling the direction of the transmitted data according to the properties of a radio channel, the control unit is further configured to:

allocate identical data to be transmitted from each antenna of the first transceiver unit by copying a data stream into several data streams, wherein a number of data streams corresponds to a number of antennas in the first transceiver unit; and

control the direction of transmission according to transmit direction information received from the second transceiver unit.

14. The transceiver unit of claim 12 , wherein the control unit is further configured to receive, through the communication interface from the other transceiver unit, an eigenvector indicating at least one direction into which data should be transmitted, and to transmit data into the at least one direction indicated by the eigenvector.

15. A transceiver unit in a telecommunication system, the transceiver unit comprising:

a communication interface including a plurality of antennas for transmitting and receiving information signals and

a control unit connected to the communication interface, the control unit being configured to select, during an active communication link with another transceiver unit, a data transmission scheme for the other transceiver unit based on a quality of the communication link, and to transmit antenna correlation information associated with the other transceiver unit, the data transmission scheme being selected from a list including at least one of,

transmitting different data from each antenna of the other transceiver unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the other transceiver unit and controlling a direction of the transmitted identical data according to properties of a radio channel.

16. The transceiver unit of claim 15, wherein the control unit is further configured to determine a quality of the communication link by calculating a signal-to-noise ratio or signal-to-interference-plus-noise ratio of a signal received from the other transceiver unit.

17. The transceiver unit of claim 15, wherein the control unit is further configured to receive a pilot signal transmitted from the other transceiver unit, calculate signal-to-noise ratio and antenna correlation information of the other transceiver unit from the received pilot signal, select the data transmission scheme for the other transceiver unit based on the calculated signal-to-noise ratio and the other transceiver unit antenna correlation information, and to transmit information on the selected data transmission scheme to the other transceiver unit.

18. The transceiver unit of claim 17, wherein the control unit is further configured to calculate a maximum data transfer capacity for each data transmission scheme based on the calculated signal-to-noise ratio and antenna correlation information of the other transceiver unit, and to select the data transmission scheme resulting in a highest maximum data transfer capacity.

19. The transceiver unit of claim 18, wherein the control unit is further configured to calculate an antenna covariance matrix of the other transceiver unit from the received pilot signal, calculate at least one eigenvalue decomposition for the antenna covariance matrix of the other transceiver unit, to obtain an eigenvalue matrix and an eigenvector matrix, wherein the eigenvalues are equal when calculating the maximum data transfer capacity for the transmission scheme of transmitting different data from each antenna of the other transceiver unit, and wherein all eigenvalues but a largest one are set to zero when calculating the maximum data transfer capacity for the transmission scheme of transmitting the same data from each antenna of the other transceiver unit and controlling the direction of the transmitted data according to the properties of a radio channel.

20. A telecommunication system, transceiver unit and a second transceiver unit in communication with the first transceiver unit;

wherein the first transceiver unit includes a communication interface including a plurality of antennas for transmitting and receiving information signals, and a control unit connected to the communication interface, the control unit of the first transceiver unit being configured to select a data transmission scheme based on data transmission scheme information received from the second transceiver unit and transmit data through the communication interface according to the selected data transmission scheme; and

wherein the second transceiver unit includes a communication interface including a plurality of antennas for transmitting and receiving information signals, and a control unit connected to the communication interface, the control unit of the second transceiver unit being configured to select, during an active communication link between the first and the second transceiver unit, a data transmission scheme for the first transceiver unit based on a quality of the communication link and transmit antenna correlation information associated with the first transceiver unit, the data transmission scheme being selected from a list including at least one of,

transmitting different data from each antenna of the first transceiver unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the first transceiver unit and controlling a direction of the transmitted identical data according to properties of a radio channel.

21. A transmitter unit in a telecommunication system, the transmitter unit comprising:

a communication interface including a plurality of antennas for transmitting information signals; and

a control unit connected to the communication interface, the control unit being configured to select a data transmission scheme based on data transmission scheme selection instructions and to transmit data through the communication interface according to the selected data transmission scheme, the data transmission scheme being selected from a list including at least one of,

transmitting different data from each antenna of the communication interface, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the communication interface and controlling direction of the transmitted identical data according to the properties of a radio channel.

22. A receiver unit in a telecommunication system, the receiver unit comprising:

a communication interface including a plurality of antennas for receiving information signals; and

a control unit connected to the communication interface, the control unit being configured to select, during an active communication link with a transmitter unit, a data transmission scheme for the transmitter unit based on a quality of the communication link and transmit antenna correlation information associated with the transmitter unit, wherein the data transmission scheme is selected from a list including at least one of,;

transmitting different data from each antenna of the transmitter unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the transmitter unit and controlling direction of the transmitted identical data according to the properties of a radio channel.

23. A transceiver unit in a telecommunication system, the transceiver unit comprising:

communication means including a plurality of antennas for transmitting and receiving information signals; and

means for selecting a data transmission scheme based on data transmission scheme information received from another transceiver unit and means for transmitting data through the communication means according to the selected data transmission scheme, wherein the data transmission scheme is selected from a list including at least one of,

transmitting different data from each antenna of the communication means, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the communication means and controlling a direction of the transmitted identical data according to properties of a radio channel.

24. A transceiver unit in a telecommunication system, the transceiver unit comprising:

communication means including a plurality of antennas for transmitting and receiving information signals; and

means for selecting, during an active communication link with another transceiver unit, a data transmission scheme for the other transceiver unit based on a quality of the communication link and to transmit antenna correlation information associated with the other transceiver unit, wherein the data transmission scheme is selected from a list including at least one of,

transmitting different data from each antenna of the other transceiver unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the other transceiver unit and controlling a direction of the transmitted identical data according to properties of a radio channel.

25. A transmitter unit in a telecommunication system, the transmitter unit comprising:

communication means including a plurality of antennas for transmitting information signals; and

means for selecting a data transmission scheme based on data transmission scheme selection instructions; and

means for transmitting data through the communication means according to the selected data transmission scheme, wherein the data transmission scheme is selected from a list including at least one of,

transmitting different data from each antenna of the communication means, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the communication means and controlling direction of the transmitted data according to properties of a radio channel.

26. A receiver unit in a telecommunication system, the receiver unit comprising:

communication means comprising a plurality of antennas for receiving information signals; and

means for selecting, during an active communication link with a transmitter unit, a data transmission scheme for the transmitter unit based on a quality of the communication link and transmit antenna correlation information associated with the transmitter unit, wherein data transmission scheme is selected from a list including at least one of,

transmitting different data from each antenna of the transmitter unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the transmitter unit and controlling a direction of the transmitted data according to properties of a radio channel.

27. A computer program embodied on computer-readable medium comprising computer code for executing a computer process for data transmission in a telecommunication system, the process comprising:

selecting, during an active communication link between a first and a second transceiver unit, a data transmission scheme for the first transceiver unit based on a quality of the communication link and transmit antenna correlation information associated with the first transceiver unit, wherein the data transmission scheme is selected from a list including at least one of, transmitting different data from each antenna of the first transceiver unit, wherein data transmitted from one antenna is independent of data transmitted from another antenna; and

transmitting identical data from each antenna of the first transceiver unit and controlling a direction of the transmitted identical data according to properties of a radio channel.

28. The computer program distribution medium of claim 27, wherein the distribution medium includes at least one of the following mediums:

a computer readable medium, a program storage medium, a record medium, a computer readable memory, a computer readable software distribution package, a computer readable signal, a computer readable telecommunications signal, and a computer readable compressed software package.