NETWORK ASSISTED INTERFERENCE MITIGATION

• US 20150003343A1
• Filed: 06/26/2014
• Published: 01/01/2015
• Est. Priority Date: 06/28/2013
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Li, Yang, Nam, Young-Han, Xin, Yan
• Application Number:
  US14/316,215
• Publication Number:
  US 20150003343A1
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• 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: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method for network assisted interference mitigation includes identifying at least one pair of adjacent resource blocks within a same subframe. The at least one pair includes a low power resource block (RB) and a high power RB. The low power RB has a substantially lower beamforming gain compared to the high beamforming gain of the high power RB such that a ratio (R) comparing receive powers of the high power RB and the low power RB to each other is greater than a threshold ratio (μ). The method includes reducing a transmit power of the high power RE to a reduced transmit power level at which the ratio R is less than or equal to the threshold ratio μ (R≦μ).

Claims

1. A method comprising:

identifying at least one pair of adjacent resource blocks within a same subframe, the at least one pair including a low power resource block (RB) and a high power RB, wherein the low power RB has a substantially lower beamforming gain compared to the high beamforming gain of the high power RB such that a ratio (R) comparing receive powers of the high power RB and the low power RB to each other is greater than a threshold ratio (μ

); and

reducing a transmit power of the high power RB to a reduced transmit power level at which the ratio R is less than or equal to the threshold ratio μ

(R≦

μ

), and

transmitting zero power at REs of the high power RB that are adjacent to the low power RB.

2. The method of claim 1, wherein reducing the transmit power of the high power RB to the reduced transmit power level further comprises:

in response to determining that the high power RB belongs to a first user equipment (UE₁) and that the low power RB belongs to a second user equipment (UE₂), reducing the transmit power of the UE₁'"'"'s high power RB to the reduced transmit power level.

3. The method of claim 1, wherein reducing the transmit power of the high power RB to the reduced transmit power level further comprises:

in response to determining that the high power RB belongs to a first channel and that the low power RB belongs to a second channel, reducing the transmit power of the first channel'"'"'s high power RB to the reduced transmit power level.

4. The method of claim 1, wherein reducing the transmit power of the high power RB to a reduced transmit power level further comprises:

muting REs in the high power RB that are adjacent to the low power RB to zero power.

5. The method of claim 1, wherein reducing the transmit power of the high power RB to the reduced transmit power level further comprises:

in response to determining that the low power RB has a higher priority than the high power RB, reducing the transmit power of the high power RB to the reduced transmit power level.

6. The method of claim 1, wherein the reduced transmit power level is determined by one of two equations:

9. The base station of claim 1, wherein the processing circuitry is further configured to:

in response to determining that the high power RB belongs to a first channel and that the low power RB belongs to a second channel, reducing the transmit power of the first channel'"'"'s high power RB to the reduced transmit power level

7. A base station comprising:

processing circuitry configured to;

identify at least one pair of adjacent resource blocks within a same subframe, the at least one pair including a low power resource block (RB) and a high power RB, wherein the low power RB has a substantially lower estimate of receive power compared to the high power RB such that a ratio (R) comparing receive powers of the high power RB and the low power RB to each other is greater than a threshold ratio (μ

), and

reduce a transmit power of the high power RB to a reduced transmit power level at which the ratio R is less than or equal to the threshold ratio μ

(R≦

μ

), and

control a transmitter to transmit zero power at REs of the high power RB that are adjacent to the low power RB; and

the transmitter configured to transmit a signal using the reduced transmit power level.

8. The base station of claim 7, wherein the processing circuitry is further configured to:

in response to determining that the high power RB belongs to a first user equipment (UE₁) and that the low power RB belongs to a second user equipment (UE₂), reduce the transmit power of the UE₁'"'"'s high power RB to the reduced transmit power level.

10. The base station of claim 7, wherein the processing circuitry is further configured to:

in response to determining that the low power RB has a higher priority than the high power RB, reducing the transmit power of the high power RB to the reduced transmit power level.

11. The base station of claim 7, wherein the processing circuitry is further configured to reduce the transmit power of the high power RB to a reduced transmit power level by muting resource elements in the high power RB that are adjacent to the low power RB to zero power.

12. The base station of claim 7, wherein the reduced transmit power level is determined by one of two equations:

13. The base station of claim 7, wherein the high power RB is a precoded RB and the low power RB is an unprecoded RB.

14. A method comprising:

identifying at least a first subframe (k), wherein each identified subframe includes a first resource block (RB) having high beamforming gain;

configuring an user equipment (UE) whether to expect a resource element guarding pattern to be ON or OFF in each RB in the first subframe.

15. The method of claim 14, further comprising configuring the UE whether to expect a resource guarding pattern in each RB in a second subframe (k+1) next following the first subframe;

configuring the advanced user UE to expect a resource guarding pattern to be ON in the RB of the first subframe;

configuring the advanced user UE to expect a resource guarding pattern to be OFF the RB of the in the second subframe.

16. The method of claim 14, wherein configuring the advanced UE whether to expect resource element guarding pattern in a channel comprises:

an implicit configuration by transmission scheme, wherein the advanced UE assumes an RE guarding pattern based on a scheduled transmission scheme;

an implicit configuration by transmission mode, wherein the advanced UE assumes an RE guarding pattern based on a configured transmission mode.

17. The method of claim 14, wherein configuring the advanced UE whether to expect resource element guarding pattern in a channel comprises one of:

transmitting one bit of information to indicate whether an RE guarding pattern is ON or OFF; and

transmitting at least two-bits of information to the advanced UE indicating whether an RE guarding pattern is OFF and if ON, further indicating a selected RE guarding pattern, selected from a plurality of RE guarding patterns.

18. The method of claim 17, wherein the plurality of RE guarding patterns include three different guarding patterns, including:

a CRS port 1 RE guarding pattern,

a CRS port 2 RE guarding pattern, and

a CSI-RS port 1 RE guarding pattern.

19. The method of claim 14, wherein configuring an advanced user equipment (UE) whether to expect resource element guarding pattern in a channel comprises:

using higher layer signal including a radio resource control (RRC) protocol layer.

20. The method of claim 14, further comprising transmitting a power reduction indicator to the advanced UE indicating a power ratio of the first RB, the power ratio being a transmit power of guard resources element (REs) compared to a transmit power of other Physical Downlink Shared Channel (PDSCH) REs within the first RB.

21. The method of claim 20, wherein the power ratio is infinitely negative (−

∞

) yielding muted guard REs having a zero value transmit power.

22. The method of claim 20, wherein the power reduction indicator includes at least two-bits of state information, and

wherein the two-bits indicate a selected power ratio according to the table below:

23. The method of claim 20, wherein the power reduction indicator includes at least two-bits of state information, and

wherein the two-bits indicate a selected power ratio according to the table below:

24. The method of claim 14, wherein configuring the advanced UE whether to expect resource element guarding pattern in a channel comprises transmitting at least two-bits of state information, the at least two-bits including at least one bit indicating a selected RE guarding pattern and at least another bit indicating a power ratio of the first RB.