Interference mitigation in asymmetric LTE deployment

Patent metadata

Field	Value
Publication number	US-10009904-B2
Application number	US-201314404437-A
Country	US
Kind code	B2
Filing date	May 24, 2013
Priority date	May 31, 2012
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

Interference mitigation solutions are disclosed for interference experienced based on asymmetric uplink (UL)/downlink (DL) slot configuration. The aggressor/victim network entities are identified using either measurement or static/semi-static means, such that the victim network entities that may be impacted by interference from aggressor network entity transmissions are identified. Inter Cell Interference Coordination (ICIC) mechanisms are extended to negotiate and address scheduling that intelligently mitigates interference that occurs in the colliding slots.

First claim

What is claimed is:

1. A method of wireless communication, comprising:
obtaining condition quality measurements by an aggressor evolved nodeB (eNB) associated with one or more network entities;
identifying, by the aggressor eNB, one or more victim network entities subject to interference from asymmetric uplink (UL)/downlink (DL) slots based on the condition quality measurements;
transmitting, by the aggressor eNB, a control signal to the one or more victim network entities, wherein the control signal relates to mitigation of the interference;
receiving, by the aggressor eNB, an overload indicator indicating a level of interference on at least one resource block attributed to at least one aggressor user equipment (UE) being served by the aggressor eNB, wherein the level of interference on the at least one resource block is one of: low, medium, and high; and
initiating a resource block mitigation operation in response to the received overload indicator, wherein the resource block mitigation operation includes at least one of:
directing the at least one aggressor UE to reduce transmit power on the at least one resource block, and
directing the at least one aggressor UE to reschedule transmissions scheduled on the at least one resource block.

2. The method of claim 1 , wherein the at least one aggressor UE is one of the one or more network entities.

3. The method of claim 2 , further comprising:
comparing the condition quality measurements, wherein the condition quality measurements are associated with the at least one aggressor UE and remaining ones of the one or more network entities; and
wherein the identifying is based, at least in part, on the comparing.

4. The method of claim 3 , wherein the conditional quality measurements comprise one or more of:
a reference signal receive power (RSRP);
a reference signal receive quality (RSRQ);
pathloss measurements to the serving eNB and the one or more neighboring eNBs;
a channel quality indicator (CQI); or
a combination thereof.

5. The method of claim 1 , further comprising:
adjusting, by the aggressor eNB, an initial transmission power in response to the received overload indicator.

6. The method of claim 1 , wherein the obtaining comprises receiving the condition quality measurements from the one or more network entities, and wherein the identifying comprises analyzing the condition quality measurements to determine the one or more victim network entities.

7. The method of claim 1 , wherein the obtaining comprises measuring the condition quality measurements associated with the one or more network entities, and wherein the identifying comprises analyzing the condition quality measurements to determine the one or more victim network entities.

8. The method of claim 1 , further comprising:
partitioning a downlink slot at the aggressor eNB according to frequency; and
assigning a first frequency for downlink data in the downlink slot, wherein the first frequency corresponds to an almost blank resource in a corresponding uplink slot of the one or more victim network entities.

9. The method of claim 1 , further comprising:
decoding, at the aggressor eNB, uplink grant information of the one or more victim network entities; and
scheduling downlink transmission at the aggressor eNB to avoid collision with uplink transmission indicated in the decoded uplink grant information.

10. The method of claim 1 , further comprising:
receiving, at the aggressor eNB, uplink transmission information over a backhaul interface from the one or more victim network entities; and
scheduling downlink transmission at the aggressor eNB to avoid collision with uplink transmission indicated in the uplink transmission information.

11. The method of claim 10 , wherein the scheduling comprises:
scheduling a downlink subframe conflicting with an uplink subframe of the one or more victim network entities as an almost blank subframe (ABS).

12. A method of wireless communication, comprising:
receiving a control signal at a victim evolved nodeB (eNB) from an aggressor eNB, wherein the control signal indicates transmission conditions indicative of interference at the victim eNB;
scheduling, by the victim eNB, transmissions associated with the victim eNB to mitigate the interference;
detecting a level of interference in one or more resource blocks (RBs) assigned to one or more victim UEs being served by the victim eNB, wherein the level of interferences in the one or more RBs is one of: low, medium, and high; and
transmitting an overload indicator to the aggressor eNB, in response to the detecting, indicating the level of detected interference in the one or more RBs, wherein a resource block mitigation operation is initiated in response to the overload indicator, and wherein the resource block mitigation operation includes at least one of:
directing at least one aggressor UE being served by the aggressor eNB to reduce transmit power on the one or more RBs, and
directing the at least one aggressor UE to reschedule transmissions scheduled on the one or more RBs.

13. The method of claim 12 , wherein the control signal indicates high interference expected from the aggressor eNB with the one or more RBs assigned to the one or more victim UEs.

14. The method of claim 13 , wherein the scheduling comprises:
scheduling, by the victim eNB, a non-victim UE of the plurality of UEs in a subframe in which the non-victim UE does not experience interference caused by the transmission conditions in the subframe.

15. The method of claim 12 , wherein the scheduling comprises:
partitioning, by the victim eNB, a transmission slot associated with the victim eNB according to frequency; and
assigning a first frequency for downlink data in the transmission slot, wherein the first frequency corresponds to an almost blank resource in a corresponding reverse transmission slot associated with the aggressor eNB.

16. The method of claim 12 , wherein the scheduling comprises:
modifying a hybrid automatic retransmission request (HARQ) timeline to avoid uplink acknowledgement (ACK)/negative acknowledgement (NACK) scheduled for an uplink slot of the victim eNB corresponding to a downlink slot of the aggressor eNB.

17. The method of claim 12 , wherein the scheduling comprises:
scheduling a blank slot in an uplink subframe of the victim eNB corresponding to a downlink subframe in the aggressor eNB.

18. A non-transitory computer-readable medium having program code recorded thereon, the program code including:
program code for causing a computer to obtain condition quality measurements by an aggressor evolved nodeB (eNB) associated with one or more network entities;
program code for causing the computer to identify, by the aggressor eNB, one or more victim network entities subject to interference from asymmetric uplink (UL)/downlink (DL) slots based on the condition quality measurements;
program code for causing the computer to transmit, by the aggressor eNB, a control signal to the one or more victim network entities, wherein the control signal relates to mitigation of the interference;
program code for causing the computer to receive, by the aggressor eNB, an overload indicator indicating a level of interference on at least one resource block attributed to at least one aggressor user equipment (UE) being served by the aggressor eNB, wherein the level of interference on the at least one resource block is one of: low, medium, and high; and
program code for causing the computer to initiate a resource block mitigation operation in respons

Assignees

• Qualcomm Inc

Inventors

• Wang Neng
• Hou Jilei
• Guo Jiming
• Feng Minghai

Classifications

• H04W72/54

  based on quality criteria · CPC title

• H04W72/541 Primary

  using the level of interference · CPC title

• H04W52/50 Primary

  at the moment of starting communication in a multiple access environment · CPC title

• H04W72/20

  Control channels or signalling for resource management · CPC title

• H04B17/309

  Measuring or estimating channel quality parameters · CPC title