Communication method and system

• US 20080150514A1
• Filed: 02/28/2007
• Published: 06/26/2008
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Juntti, Markku, Tolli, Antti, Latva-Aho, Matti, Codreanu, Marian
• Granted Patent: US 8,208,963 B2
• Time in Patent Office: Days
• US Class Current: 324/76.77
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/06 at the transmitting station
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0623 Auxiliary parameters, e.g. power control [PCB] or not acknowledged commands [NACK], used as feedback information
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0673 using feedback from receiving side

Abstract

There is provided a method comprising: determining a phase difference between at least two antenna units of a distributed antenna system on the basis of at least one pilot signal received from at least one of a plurality of antenna units; and transmitting phase correction commands to a common base station of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between at least two antenna units of the distributed antenna system.

Claims

1. A method, comprising:

determining a phase difference between at least two antenna units of a distributed antenna system on the basis of at least one pilot signal received from at least one of a plurality of antenna units; and

transmitting phase correction commands to a common base station of plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between the at least two antenna units of the distributed antenna system.

2. The method of claim 1, further comprising:

receiving the at least one pilot signal directly from the at least one of the plurality antenna units.

3. The method of claim 2, further comprising:

receiving the pilot signal during a predefined idle period dedicated for any control process.

4. The method of claim 1, further comprising:

receiving the at least one pilot signal by one or more dedicated network entities of the distributed antenna system.

5. The method of claim 4, further comprising:

determining the phase difference between the at least two antenna units in the one or more dedicated network entities; and

transmitting the phase correction commands to the common base station by the one or more dedicated network entities.

6. The method of claim 4, further comprising:

arranging the one or more dedicated network entities to include one or more transmitter/receivers dedicated for carrier phase synchronization.

7. The method of claim 1, further comprising:

compensating the phase difference between oscillators used at each antenna unit of the distributed antenna system on the basis of the phase correction commands.

8. The method of claim 1, further comprising:

providing continuous phase shift tracking by the common base station on the basis of the phase correction commands.

9. A communication system, comprising:

a plurality of antenna units of a distributed antenna system;

a common base station of the plurality of antenna units;

a processing unit configured to determine a phase difference between at least two antenna units on the basis of at least one pilot signal received from at least one of a plurality of antenna units and to provide phase correction commands to the common base station of the plurality of antenna units on the basis of the determined phase difference; and

a synchronizing unit configured to synchronize carrier phases between the at least two antenna units of the distributed antenna system on the basis of the transmitted phase correction commands.

10. The communication system of claim 9, wherein the processing unit configured to determine the phase difference resides in an antenna unit of the distributed antenna system, in a user entity of the distributed antenna system, or in one or more dedicated network entities of the distributed antenna system.

11. The communication system of claim 9, wherein the processing unit for providing the phase correction commands to the common base station resides in an antenna unit of the distributed antenna system, in a user entity, or in one or more dedicated network entities of the distributed antenna system.

12. The communication system of claim 9, wherein the at least one pilot signal is received by an antenna unit of the distributed antenna system directly from the at least one of the plurality of antenna units.

13. The communication system of claim 12, wherein the pilot signal is received during a predefined idle period dedicated for any control process.

14. The communication system of claim 9, wherein the at least one pilot signal is received by one or more dedicated network entities of the distributed antenna system.

15. The communication system-of claim 9, wherein the synchronizing unit is configured to compensate the phase difference between oscillators used at each antenna unit of the distributed antenna system on the basis of the phase correction commands.

16. The communication system of claim 9, wherein the synchronizing unit is configured to provide continuous phase shift tracking on the basis of the phase correction commands.

17. A base station, comprising:

a processing unit configured to receive phase correction commands relating to a plurality of antenna units of a distributed antenna system, the phase correction commands being determined on the basis of a determined phase difference between at least two antenna units and on the basis of at least one pilot signal from at least one of the plurality of antenna units; and

a synchronizing unit configured to synchronize carrier phases between at least two antenna units of the distributed antenna system on the basis of the received phase correction commands.

18. The base station of claim 17, wherein the processing unit is further configured to compensate the phase difference between oscillators used at each antenna unit of the distributed antenna system on the basis of the received phase correction commands.

19. The base station of claim 17, wherein the processing unit is further configured to provide continuous phase shift tracking on the basis of the received phase correction commands.

20. An antenna unit, comprising:

one or more antennas configured to enable transmission and reception of signals; and

a processing unit configured to provide a pilot signal to enable determination of a phase difference between at least part of a plurality of antenna units of a distributed antenna system, and to enable a common base station of the plurality of antenna units to synchronize carrier phases between at least two antenna units on the basis of the determined phase difference.

21. The antenna unit of claim 20, wherein the processing unit is further configured to determine the phase difference between the at least part of the plurality of antenna units of the distributed antenna system on the basis of at least one pilot signal received from at least one of the plurality of antenna units.

22. The antenna unit of claim 21, further comprising a phase correction processing unit configured to provide phase correction commands to the common base station of the plurality of antenna units on the basis of the determined phase difference.

23. The antenna unit of claim 20, wherein the one or more antenna units are configured to receive at least one pilot signal directly from at least one of the plurality of antenna units.

24. The antenna unit of claim 20, wherein the antenna unit is configured to transmit the pilot signal to one or more dedicated network entities to enable determination of the phase difference between the antenna units in the one or more dedicated network entities, and to enable the transmission of a phase correction command to the common base station by the one or more dedicated network entities.

25. A network entity, comprising:

a receiver configured to receive pilot signals from a plurality of antenna units of a distributed antenna system;

a processing unit configured to determine a phase difference between at least two antenna units on the basis of the received pilot signals; and

a transmitter configured to transmit phase correction commands to a common base station of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between the at least two antenna units of the distributed antenna system.

26. The network entity of claim 25, wherein the receiver is configured to receive the pilot signals during predefined idle periods dedicated for any control processes.

27. A computer-readable program distribution medium encoding a computer program of instructions for executing a computer process for synchronizing, the process comprising:

determining a phase difference between at least two antenna units of a distributed antenna system on the basis of at least one pilot signal received from at least one of a plurality of antenna units; and

transmitting phase correction commands to a common base station of the at least one of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between the at least two antenna units of the distributed antenna system.

28. The computer program distribution medium of claim 27, the distribution medium including at least one of the following media:

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.

29. A communication system, comprising:

a plurality of antenna units of a distributed antenna system;

a common base station of the plurality of antenna units;

processing means for determining a phase difference between at least two antenna units on the basis of at least one pilot signal received from at least one of the plurality of antenna units and for providing phase correction commands to the common base station of the plurality of antenna units on the basis of the determined phase difference; and

synchronizing means for synchronizing carrier phases between the at least two antenna units of the distributed antenna system on the basis of the transmitted phase correction commands.

30. The communication system of claim 29, wherein the processing means for determining the phase difference resides in an antenna unit of the distributed antenna system, in a user entity of the distributed antenna system, or in one or more dedicated network entities of the distributed antenna system.

31. The communication system of claim 29, wherein the processing means for providing the phase correction commands to the common base station resides in an antenna unit of the distributed antenna system, in a user entity or in one or more dedicated network entities of the distributed antenna system.

32. An antenna entity, comprising:

one or more antennas for enabling transmission and reception of signals; and

processing means for providing a pilot signal to enable the determination of a phase difference between at least two antenna units of a distributed antenna system, and for enabling a common base station of the one or more antenna units to synchronize carrier phases between at least two antenna units on the basis of the determined phase difference.

33. The antenna entity of claim 32, wherein the processing means for determining the phase difference between the at least two antenna units of a distributed antenna system on the basis of at least one received pilot signal and further comprising:

phase correction processing means for providing phase correction commands to the common base station of the plurality of antenna units on the basis of the determined phase difference.

34. The antenna entity of claim 32, further comprising:

transmitting means for transmitting the pilot signal to one or more dedicated network entities to enable the determination of the phase difference between the at least two antenna units in the one or more dedicated network entities, and for enabling the transmission of a phase correction command to the common base station by the one or more dedicated network entities.

35. A network entity, comprising:

receiving means for receiving pilot signals from a plurality of antenna units of a distributed antenna system;

processing means for determining a phase difference between at least two antenna units on the basis of the received pilot signals; and

transmitting means for transmitting phase correction commands to a common base station of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between the at least two antenna units of the distributed antenna system.

36. A base station, comprising:

processing means for receiving phase correction commands relating to a plurality of antenna units of a distributed antenna system, the phase correction commands being determined on the basis of a determined phase difference between at least two antenna units and on the basis of at least one pilot signal from at least one of the plurality of antenna units; and

synchronizing means for synchronizing carrier phases between at least two antenna units of the distributed antenna system on the basis of the received phase correction commands.