METHOD AND APPARATUS FOR INTERFERENCE MITIGATION IN HETEROGENEOUS NETWORK USING BEAMFORMING

• US 20120190378A1
• Filed: 01/25/2012
• Published: 07/26/2012
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Han, Shuangfeng, Lim, Chi-Woo
• Granted Patent: US 8,626,071 B2
• Time in Patent Office: Days
• US Class Current: 455/452.2
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A method and apparatus provide interference mitigation in a heterogeneous network using beamforming. In the method, a macro Mobile Station (MS) receives a broadcast message including a Precoding Matrix Index (PMI) set restricted in a macro cell, measures a Signal-to-Interference plus Noise Ratio (SINR) and a channel power from an adjacent femto Base Station (BS) and calculates a PMI, determines whether to request a dedicated frequency resource for a macro MS on the basis of the measured SINR, the channel power from the adjacent femto BS, and the calculated PMI, and requests the dedicated frequency resource for the macro MS from a macro BS.

Claims

1. A method for operating a femto Mobile Station (MS) for interference mitigation in a heterogeneous network using beamforming, the method comprising:

receiving a broadcast message from a femto Base Station (BS);

measuring a Signal-to-Interference plus Noise Ratio (SINR) and a channel power from an adjacent macro BS; and

feeding back a restricted Precoding Matrix Index (PMI) or a preferred PMI to the femto BS based on the measured SINR and the channel power from the adjacent macro BS.

2. The method of claim 1, wherein the broadcast message includes at least one of a first threshold value for the SINR and a second threshold value for the reception signal strength from a macro BS.

3. The method of claim 1, wherein the PMI is determined by an eigenvector of a measured covariance matrix.

4. The method of claim 1, wherein feeding back the restricted PMI or the preferred PMI to the femto BS on the basis of the measured SINR and the channel power from the adjacent macro BS comprises:

determining whether the measured SINR is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value; and

transmitting the restricted PMI or the preferred PMI to the femto BS when the measured SINR is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value.

5. The method of claim 1, wherein the heterogeneous network includes a plurality of macro cells, and one or more femto BSs overlap in one macro cell.

6. The method of claim 1, further comprising receiving information about dedicated frequency resources for macro MSs in the macro BS from the femto BS.

7. A method for operating a femto Base Station (BS) for interference mitigation in a heterogeneous network using beamforming, the method comprising:

transmitting a broadcast message;

receiving a restricted Precoding Matrix Index (PMI) or a preferred PMI from femto Mobile Stations (MSs); and

providing the PMI information to a macro BS on the basis of the PMI information received from the femto MSs.

8. The method of claim 7, wherein the broadcast message includes at least one of a first threshold value for a Signal-to-Interference plus Noise Ratio (SINR) and a second threshold value for the reception signal strength from a macro BS.

9. The method of claim 7, wherein the PMI is determined by an eigenvector of a measured covariance matrix.

10. The method of claim 7, wherein the restricted PMI or the preferred PMI is fed back from the femto MS when a Signal-to-Interference plus Noise Ratio (SINR) measured by the femto MS is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value.

11. The method of claim 7, wherein the heterogeneous network includes a plurality of macro cells, and one or more femto BSs overlap in one macro cell.

12. The method of claim 7, further comprising:

receiving, information about dedicated frequency resources for macro MSs from the adjacent femto BS; and

transmitting the information about the dedicated frequency resources for the macro MSs to the femto MS.

13. A method for operating a macro Base Station (BS) for interference mitigation in a heterogeneous network using beamforming, comprising:

receiving Precoding Matrix Index (PMI) information from femto BSs;

configuring a restricted PMI set in a macro cell on the basis of the PMI information received from the femto BS; and

transmitting. a broadcast message including the PMI set.

14. The method of claim 13, wherein the first PMI is determined by an eigenvector of a measured covariance matrix.

15. The method of claim 13, wherein the broadcast message further includes at least one of a first threshold value for a Signal-to-Interference plus Noise Ratio (SINR) and a second threshold value for the reception signal strength from the femto BS.

16. The method of claim 13, further comprising:

receiving a dedicated frequency resource request from macro MSs;

determining the ratio of a dedicated frequency resource, used only by a macro BS, to the entire frequency band on the basis of user differentiation; and

broadcasting information about the determined dedicated resource.

17. A method for operating a macro Mobile Station (MS) for interference mitigation in a heterogeneous network using beamforming, the method comprising:

receiving a broadcast message including a Precoding Matrix Index (PMI) set restricted in a macro cell;

measuring a Signal-to-Interference plus Noise Ratio (SINR) and a channel power from an adjacent femto Base Station (BS) and calculating a PMI;

determining whether to request a dedicated frequency resource for a macro MS on the basis of the measured SINR, the channel power from the adjacent femto BS, and the calculated PMI; and

requesting the dedicated frequency resource for the macro MS from a macro BS.

18. The method of claim 17, wherein the calculated PMI maximizes downlink channel power.

19. The method of claim 17, wherein the broadcast message further includes at least one of a first threshold value for a SINR and a second threshold value for the reception signal strength from the femto BS.

20. The method of claim 19, wherein determining whether to request the dedicated frequency resource for the macro MS on the basis of the measured SINR, the channel power from the adjacent femto BS, and the calculated PMI comprises determining whether the calculated PMI is within the PMI set or whether the measured SINR is smaller than the first threshold value and the channel power from the adjacent femto BS is greater than the second threshold value.

21. An apparatus of a femto Mobile Station (MS) for interference mitigation in a heterogeneous network using beamforming, the apparatus comprising:

a Radio Frequency (RF) module configured to receive a broadcast message from a femto Base Station (BS);

a processor configured to measure a Signal-to-Interference plus Noise Ratio (SINR) and a channel power from an adjacent macro BS; and

a controller configured to feed back a restricted Precoding Matrix Index (PMI) or a preferred PMI to the femto BS on the basis of the measured SINR and the channel power from the adjacent macro BS.

22. The apparatus of claim 21, wherein the broadcast message includes at least one of a first threshold value for the SINR and a second threshold value for the reception signal strength from a macro BS.

23. The apparatus of claim 21, wherein the PMI is determined by an eigenvector of a measured covariance matrix.

24. The apparatus of claim 21, wherein the controller is configured to:

determine whether the measured SINR is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value; and

transmit the restricted PMI or the preferred PMI to the femto BS when the measured SINR is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value.

25. The apparatus of claim 21, wherein the heterogeneous network includes a plurality of macro cells, and one or more femto BSs overlap in one macro cell.

26. The apparatus of claim 21, wherein the RF module receives information about dedicated frequency resources for macro MSs in the macro BS from the femto BS.

27. An apparatus of a femto Base Station (BS) for interference mitigation in a heterogeneous network using beamforming, the apparatus comprising:

a Radio Frequency (RF) module configured to transmit a broadcast message, and receive a restricted Precoding Matrix Index (PMI) or a preferred PMI from femto Mobile Stations (MSs); and

a controller configured to provide the PMI information to a macro BS based on the PMI information received from the femto MSs.

28. The apparatus of claim 27, wherein the broadcast message includes at least one of a first threshold value for a Signal-to-Interference plus Noise Ratio (SINR) and a second threshold value for the reception signal strength from a macro BS.

29. The apparatus of claim 27, wherein the PMI is determined by an eigenvector of a measured covariance matrix.

30. The apparatus of claim 27, wherein the restricted PMI or the preferred PMI is fed back from the femto MS when a SINR measured by the femto MS is smaller than the first threshold value and the channel power from the adjacent macro BS is greater than the second threshold value.

31. The apparatus of claim 27, wherein the heterogeneous network includes a plurality of macro cells, and one or more femto BSs overlap in one macro cell.

32. The apparatus of claim 27, wherein the RF module is configured to:

receive information about dedicated frequency resources for macro MSs from the adjacent femto BS; and

transmit the information about the dedicated frequency resources for the macro MSs to the femto MS.

33. An apparatus of a macro Base Station (BS) for interference mitigation in a heterogeneous network using beamforming, the apparatus comprising:

a Radio Frequency (RF) module configured to receive Precoding Matrix Index (PMI) information from femto BSs;

a controller configured to configure a restricted PMI set in a macro cell on the basis of the PMI information received from the femto BS; and

a processor configured to transmit a broadcast message including the PMI set.

34. The apparatus of claim 33, wherein the first PMI is determined by an eigenvector of a measured covariance matrix.

35. The apparatus of claim 33, wherein the broadcast message further includes at least one of a first threshold value for a Signal-to-Interference plus Noise Ratio (SINR) and a second threshold value for the reception signal strength from the femto BS.

36. The apparatus of claim 33, wherein:

the RF module is configured to receive a dedicated frequency resource request from macro MSs;

the controller is configured to determine the ratio of a dedicated frequency resource, used only by a macro BS, to the entire frequency band on the basis of user differentiation; and

the processor is configured to broadcast information about the determined dedicated resource.

37. An apparatus of a macro Mobile Station (MS) for interference mitigation in a heterogeneous network using beamforming, the apparatus comprising:

a Radio Frequency (RF) module configured to receive a broadcast message including a Precoding Matrix Index (PMI) set restricted in a macro cell; and

a controller configured to measure a Signal-to-Interference plus Noise Ratio (SINR) and a channel power from an adjacent femto Base Station (BS) and calculate a PMI, determine whether to request a dedicated frequency resource for a macro MS on the basis of the measured SINR, the channel power from the adjacent femto BS, and the calculated PMI, and request the dedicated frequency resource for the macro MS from a macro BS.

38. The apparatus of claim 37, wherein the calculated PMI maximizes downlink channel power.

39. The apparatus of claim 37, wherein the broadcast message further includes at least one of a first threshold value for a SINR and a second threshold value for the reception signal strength from the femto BS.

40. The apparatus of claim 39, wherein the controller determines whether the calculated PMI is within the PMI set or whether the measured SINR is smaller than the first threshold value and the channel power from the adjacent femto BS is greater than the second threshold value.