Control channel configuration in a wireless communications system

1. A method in a control node of a wireless communication network for allocating resource elements of a transmission resource to a control channel, wherein the transmission resource comprises a first number of resource blocks, each resource block comprising one or a plurality of subsets of resource elements, the method comprising:

obtaining a bitmap for configuration of the transmission resource, wherein the bitmap is configured to identify at least one subset of resource elements within the transmission resource;

allocating the at least one identified subset of resource elements to the control channel;

transmitting the bitmap to a receiving node; and

transmitting control data on the at least one subset of resource elements allocated to the control channel to the receiving node;

wherein obtaining the bitmap for configuration of the transmission resource comprises:

obtaining separate bitmaps for configuration of the transmission resource for multiple aggregation levels; and

selecting one bitmap for configuration of the transmission resource according to a configured aggregation level.

2. The method of claim 1 , further comprising:

identifying individually each subset of resource elements of the transmission resource individually to be part of the control channel or not, based on the selected bitmap.

3. The method of claim 1 , wherein the selected bitmap relates a separate bit to each subset of resource elements of the transmission resource.

4. The method of claim 1 , further comprising:

grouping the subsets of resource elements in blocks of subsets of resource elements, wherein one block of subsets comprises two or more subsets; and

identifying each block of subsets individually to be part of the control channel or not, based on the selected bitmap.

5. The method of claim 4 , wherein the selected bitmap relates a separate bit to each block of subsets of resource elements of the transmission resource.

6. The method of claim 1 , further comprising:

identifying each of the resource blocks of the transmission resource individually to be used for the control channel or not, based on the selected bitmap;

indicating one or more subsets of one resource block; and

identifying the one or more indicated subsets to be part of the control channel or not in every resource block identified as to be used for the control channel.

7. The method of claim 1 , further comprising:

setting a starting position within the selected bitmap;

reusing the selected bitmap, based on the starting position, to configure the entire transmission resource.

8. The method of claim 1 , wherein the selected bitmap configures a predefined subset of the number of resource blocks or the plurality of subsets of resource elements of the transmission resource.

9. The method of claim 1 , wherein an allocation of resource elements to at least one of the subsets of resource elements is based on optimizing a transmission property.

10. A method in a receiving node of a wireless communication network for allocating resource elements of a transmission resource to a control channel, wherein the transmission resource comprises a first number of resource blocks, each resource block comprising one or a plurality of subsets of resource elements, the method comprising:

receiving, from a control node, a bitmap for configuration of the transmission resource, wherein the bitmap is configured to identify at least one subset of resource elements within the transmission resource;

allocating the at least one identified subset of resource elements to the control channel; and

searching for control data on the at least one subset of resource elements allocated to the control channel;

wherein the method further comprises:

obtaining separate bitmaps for configuration of the transmission resource for multiple aggregation levels; and

selecting one bitmap for configuration of the transmission resource according to a configured aggregation level.

11. The method of claim 10 , further comprising:

identifying individually each subset of resource elements of the transmission resource to be part of the control channel or not, based on the selected bitmap.

12. The method of claim 10 , wherein the selected bitmap relates a separate bit to each subset of resource elements of the transmission resource.

13. The method of claim 10 , further comprising:

grouping the subsets of resource elements in blocks of subsets of resource elements, wherein one block of subsets comprises two or more subsets; and

identifying each block of subsets individually to be part of the control channel or not, based on the selected bitmap.

14. The method of claim 13 , wherein the selected bitmap relates a separate bit to each block of subsets of resource elements of the transmission resource.

15. The method of claim 10 , further comprising:

identifying each of the resource blocks of the transmission resource individually to be used for the control channel or not, based on the selected bitmap;

indicating one or more subsets of one resource block; and

identifying the one or more indicated subsets to be part of the control channel or not in every resource block identified as to be used for the control channel.

16. The method of claim 10 , further comprising:

setting a starting position within the selected bitmap; and

reusing the selected bitmap based on the starting position to configure the entire transmission resource.

17. The method of claim 10 , wherein the selected bitmap configures a predefined subset of the number of resource blocks or the plurality of subsets of resource elements of the transmission resource.

18. The method of claim 10 , wherein an allocation of resource elements to at least one of the subsets of resource elements is based on optimizing a transmission property.

19. A control node for a wireless communication network and for allocating resource elements of a transmission resource to a control channel, wherein the transmission resource comprises a first number of resource blocks, each resource block comprising one or a plurality of subsets of resource elements, the control node comprising:

a transceiver circuit configured to transmit data to a receiving node; and

a processor circuit configured to:

obtain a bitmap for configuration of the transmission resource, wherein the bitmap is configured to identify at least one subset of resource elements within the transmission resource;

allocate the at least one identified subset of resource elements to the control channel;

transmit control data, using the transceiver circuit, on the at least one subset of resource elements allocated to the control channel to a receiving node; and

transmit the bitmap to the receiving node, using the transmitter circuit;

wherein the processor circuit is configured to obtain the bitmap for configuration of the transmission resource by:

obtaining separate bitmaps for configuration of the transmission resource for multiple aggregation levels; and

selecting one bitmap for configuration of the transmission resource according to a configured aggregation level.

20. A receiving node for a wireless communication network, configured to allocate resource elements of a transmission resource to a control channel, wherein the transmission resource comprises a first number of resource blocks, each resource block comprising one or a plurality of subsets of resource elements, the receiving node comprising:

a transceiver circuit; and

a processor circuit configured to:

receive, via the transceiver circuit, a bitmap for configuration of the transmission resource, wherein the bitmap is configured to identify at least one subset of resource elements within the transmission resource;

allocate the at least one identified subset of resource elements to the control channel; and

search for control data on the at least one subset of resource elements allocated to the control channel;

wherein the processor circuit is further configured to:

obtain separate bitmaps for configuration of the transmission resource for multiple aggregation levels; and

select one bitmap for configuration of the transmission resource according to a configured aggregation level.