COMMUNICATIONS SYSTEM USING BEAMFORMING

• US 20120257683A1
• Filed: 12/29/2010
• Published: 10/11/2012
• Est. Priority Date: 12/30/2009
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Schwager, Andreas, Stadelmeier, Lothar, Schneider, Daniel
• Granted Patent: US 9,020,049 B2
• Time in Patent Office: Days
• US Class Current: 375/257
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 3/00 Line transmission systems combined with near-field transmission systems H04B5/00
• CPC Class Codes: H04B 3/50 Systems for transmission between fixed stations via two-conductor transmission lines H04B3/54 takes precedence
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/0284 Arrangements to ensure DC-balance
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/367 using predistortion
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 : Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/1461 : Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

In a MIMO communications system a first communications device applies beamforming to a complete transmission packet including both synchronization data and either payload data or training symbols. A second communications device evaluates the beamformed synchronization data and determines and transmits a feedback information indicating minimum required synchronization data and/or a minimum number of training symbols. The first communications device tailors the synchronization data and/or number of training symbols on the basis of the feedback information. Beamforming the complete transmission packet facilitates signal suppression at defined locations. When the channel properties change, the second communications device may provide further channel state information to adapt beamforming in the first communications device without transmission of not beamformed training symbols. The communications system may be a powerline telecommunications system.

Claims

1-15. -15. (canceled)

16. A communications device comprising:

a transmitter unit configured to transmit at least two parallel transmit signals via a transmission channel, wherein each transmit signal includes synchronization data respectively; and

a precode unit configured to beamform the transmit signals in accordance with a first channel state information.

17. The communications device of claim 16, wherein

the transmit signals further include payload data or training symbols or both.

18. The communications device of claim 16, further comprising:

a control unit configured to modify the synchronization data in accordance with a feedback information; and

an input unit configured to receive the first channel state information and the feedback information and to output the first channel state information to the precode unit and the feedback information to the control unit.

19. The communications device of claim 16, wherein

the precode unit is configured to beamform the transmit signals in the time domain.

20. The communications device of claim 16, wherein

a power line communications system provides the transmission channel.

21. The communications device of claim 16, further comprising:

a precoder control unit configured to control the precode unit in response to the first channel state information; and

a codebook unit configured to store at least a codebook including a plurality of different predefined matrices, wherein

the precoder control unit is further configured to select from the codebook one of the predefined matrices as a precode matrix in accordance with the first channel state information.

22. The communications device of claim 16, further comprising:

a precoder control unit configured to control the precode unit in response to the first channel state information, wherein

the precoder control unit is further configured to determine the precode matrix used for transmission via the first transmission channel on the basis of the first channel state information and a second channel state information describing a second transmission channel to a further communications device such that signal power at the further communications device is minimized.

23. A communications device comprising:

a receiver unit configured to receive at least one receive signal via a transmission channel;

wherein the at least one receive signal has been beamformed before transmission on the basis of channel state information describing the transmission channel, and

wherein each receive signal includes beamformed synchronization data.

24. The communications device of claim 23, wherein

the at least one receive signal further includes payload data or training symbols or both.

25. The communications device of claim 23, wherein

a power line communications system provides the transmission channel.

26. The communications device of claim 23, further comprising:

a qualification unit configured to generate a feedback information describing a minimum synchronization data and/or a minimum number of training symbols required for undisturbed reception of the payload data and synchronization data on the basis of the at least one receive signal; and

an output unit configured to output the feedback information.

27. The communications device of claim 26, wherein

the qualification unit is further configured to detect a change of transmission properties of the transmission channel and to generate an updated channel state information;

and

the output unit is further configured to output the updated channel state information.

28. The communications device of claim 27, wherein

the qualification unit is further configured to generate the updated channel state information on the basis of beamformed receive signals and the previous channel state information, and

the output unit is further configured to output the updated channel state information.

29. The communications device of claim 26, further comprising:

a codebook unit configured to store a codebook including a plurality of different predefined matrices and a two-dimensional look-up table, wherein an entry of the look-up table identifies that one of the predefined matrices that fits best with a product matrix obtained by multiplying two of the predefined matrices, wherein

the qualification unit is further configured to generate the updated channel state information on the basis of a matrix obtained by singular value decomposition of a channel matrix representing the channel state information obtained from not beamformed receive signals and another matrix obtained by singular value decomposition of an equivalent transmission channel resulting from transmission of beamformed signals.

30. The communications device of claim 29, wherein

the qualification unit is further configured to compare a first distance metric between a current optimum beam forming matrix and a currently used beam forming matrix and a second distance metric between the current optimum beam forming matrix and that one of the predefined matrices that fits best with the current optimum beam forming matrix,

the qualification unit is further configured to generate select information representing a result of the comparison, and

the output unit is further configured to output the select information.