Network node and a method therein for controlling uplink power control

1. A method, in a network node in a wireless communication network, for controlling uplink power control within an area comprising at least one macro Radio Base Station (RBS) and at least one low power RBS, the method comprising:

collecting measurement reports from one or more user equipment (UE) located within the area;

creating clusters of low power RBSs and macro RBSs based on the collected measurement reports, wherein each cluster comprises one low power RBS and at least one macro RBS;

for each low power RBS in a cluster, identifying both a macro RBS with a lowest pathloss based on the collected measurement reports for those UE connected to the low power RBS and the level of the pathloss;

determining, based on the collected measurement reports for those UE connected to the identified macro RBS, an interference level in the low power RBS caused by UE connected to the identified macro RBS;

selecting an uplink power control setting for the low power RBS based on the size of the pathloss associated with the identified macro RBS and the interference level in the low power RBS caused by UE connected to the identified macro RBS; and

instructing UE connected to the low power RBS to use the selected uplink power control setting.

2. The method of claim 1 , wherein:

the measurement reports comprise Reference Signal Received Power (RSRP); and

the wireless communication network is employing Long Term Evolution (LTE).

3. The method of claim 1 :

further comprising estimating a traffic load in the low power RBS;

further comprising weighting the pathloss associated with the identified macro RBS with the estimated traffic load; and

wherein the selecting the uplink power control setting for the low power RBS is also based on the weighted pathloss.

4. The method of claim 1 , further comprising:

receiving information relating to transmission power of the identified macro RBS;

determining pathloss based on the collected measurement reports for those UE connected to the low power RBS and the transmission power of the identified macro RBS.

5. The method of claim 1 , wherein the network node is a low power RBS.

6. The method of claim 5 , wherein collecting measurement reports from UE being located within the area comprises:

receiving measurement reports from UE connected to the low power RBS; and

receiving measurement reports from UE connected to one or more macro RBSs which have a pathloss to the low power RBS.

7. The method of claim 1 , wherein the network node is an Operations, Administration and Maintenance (OAM) node.

8. The method of claim 1 , wherein the network node is a Radio Network Controller (RNC) or a Base Station Controller (BSC).

9. The method of claim 1 , wherein collecting measurement reports from the one or more UE located within the area comprises receiving measurement reports forwarded by the at least one macro RBS and the at least one low power RBS.

10. The method of claim 1 , wherein the creating of clusters comprises:

identifying, for each low power RBS, one or more macro RBSs having a lowest pathloss; and

clustering each respective low power RBS with the one or more macro RBSs having the lowest pathloss.

11. The method of claim 1 , wherein a first cluster of the clusters comprises a plurality of macro RBS that neighbor the low power RBS of the first cluster.

12. A method, in a network node in a wireless communication network, for controlling uplink power control within an area comprising at least one macro Radio Base Station (RBS) and at least one low power RBS, the method comprising:

collecting measurement reports from one or more user equipment (UE), located within the area;

creating clusters of low power RBSs and macro RBSs based on the collected measurement reports, wherein each cluster comprises one low power RBS and at least one macro RBS;

for one or more macro RBSs of a cluster, determining a current uplink signal quality for the one or more macro RBSs based on a received report from the corresponding macro RBS;

comparing a current uplink signal quality to a previously determined uplink signal quality;

adjusting a current uplink power control setting for a low power RBS based on the comparison; and

instructing UE connected to the low power RBS to use the adjusted uplink power control setting.

13. The method of claim 12 :

further comprising determining a current uplink signal quality for the low power RBS;

wherein the adjusting the current uplink power control setting for the low power RBS is also based on the current uplink signal quality for the low power RBS.

14. The method of claim 13 , wherein the current uplink power control setting for the low power RBS is adjusted upwards in response to the current uplink signal quality for the low power RBS being below a predefined threshold.

15. The method of claim 12 , wherein the current uplink power control setting for the low power RBS is adjusted downwards in response to the comparison indicating a deteriorated uplink signal quality below a predefined threshold for UE connected to the macro RBS.

16. A network node, in a wireless communication network, adapted to control uplink power control within an area comprising at least one macro Radio Base Station (RBS) and at least one low power RBS, the network node comprising a processor and a memory, the memory containing instructions executable by the processor whereby the network node is configured to:

collect measurement reports from one or more user equipment (UE) located within the area;

create clusters of low power RBSs and macro RBSs based on the collected measurement reports, wherein each cluster comprises one low power RBS and at least one macro RBS;

for each low power RBS in a cluster, identify a macro RBS with a lowest pathloss based on the collected measurement reports for UE connected to a low power RBS and the level of the pathloss;

determine, based on the collected measurement reports for those UE connected to the identified macro RBS, an interference level in the low power RBS caused by UE connected to the identified macro RBS;

select an uplink power control setting for the low power RBS based on both a size of the pathloss associated with identified macro RBS and the interference level in the low power RBS caused by UE connected to the corresponding macro RBS; and

instruct UE connected to the low power RBS to use the selected uplink power control setting.

17. The network node of claim 16 , wherein:

the measurement reports comprise Reference Signal Received Power (RSRP); and

the wireless communication network is employing Long Term Evolution (LTE).

18. The network node of claim 16 , wherein the memory contains instructions executable by the processor whereby the network node is configured to:

estimate a traffic load in the low power RBS;

weight the pathloss associated with the identified macro RBS with the estimated traffic load; and

select the uplink power control setting for the low power RBS also based on the weighted pathloss.

19. The network node of claim 16 , wherein the memory contains instructions executable by the processor whereby the network node is configured to:

receive information relating to the transmission power of the identified macro RBS; and

determine the pathloss based on both the collected measurement reports for those UE being connected to the low power RBS and the transmission power of the identified macro RBS.

20. The network node of claim 16 , wherein the network node is a low power RBS.

21. The network node of claim 20 , wherein the memory contains instructions executable by the processor whereby the network node is configured to receive measurement reports from UE connected to the low power RBS and measurement reports from UE connected to one or more macro RBSs which have a pathloss to the low power RBS, thereby collecting measurement reports from UE located within the area.

22. The network node of claim 16 , wherein the network node is an Operations, Administration and Maintenance (OAM) node.

23. The network node of claim 16 , wherein the network node is a Radio Network Controller (RNC) or a Base Station Controller (BSC).

24. The network node of claim 16 , wherein the memory contains instructions executable by the processor whereby the network node is configured to collect measurement reports from UE located within the area by receiving measurement reports forwarded by the at least one macro RBS and the at least one low power RBS.

25. The network node of claim 16 wherein the memory contains instructions executable by the processor whereby the network node is configured to:

identify, for each low power RBS, one or more macro RBSs having lowest pathloss; and

cluster each respective low power RBS with one or more corresponding macro RBSs having the lowest pathloss.

26. A network node, in a wireless communication network, configured to control uplink power control within an area comprising at least one macro Radio Base Station (RBS) and at least one low power RBS, the network node comprising a processor and a memory, the memory containing instructions executable by the processor whereby the network node is configured to:

collect measurement reports from one or more user equipment (UE) located within the area;

create clusters of low power RBSs and macro RBSs based on the collected measurement reports, wherein each cluster comprises one low power RBS and at least one macro RBS;

for one or more macro RBSs of a cluster, determine a current uplink signal quality for the one or more macro RBSs based on a received report from the corresponding macro RBS;

compare a current uplink signal quality to a previously determined uplink signal quality;

adjust a current uplink power control setting for a low power RBS of the cluster based on the comparison; and

instruct one or more UE connected to the low power RBS to use the adjusted uplink power control setting.

27. The network node of claim 26 , wherein the memory contains instructions executable by the processor whereby the network node is configured to:

determine a current uplink signal quality for the low power RBS; and

adjust the current uplink power control setting for the low power RBS based on the current uplink signal quality for the low power RBS.

28. The network node of claim 26 , wherein the memory contains instructions executable by the processor whereby the network node is configured to adjust the current uplink power control setting for the low power RBS downwards in response to the comparison indicating a deteriorated uplink signal quality below a predefined threshold for UE connected to the macro RBS.

29. The network node of claim 26 , wherein the memory contains instructions executable by the processor whereby the network node is configured to adjust the current uplink power control setting for the low power RBS in response to the current uplink signal quality for the low power RBS being below a predefined threshold.