Method and apparatus for configuring resource elements for the provision of channel state information reference signals

1. A method of configuring resource elements for provision of channel state information reference signals, the method comprising:

receiving a definition of a plurality of resource elements of a physical resource block (PRB) to be allocated for the provision of channel state information reference signals for a mobile terminal, wherein at least some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals correspond in position to resource elements of the PRB that are configured to be interpreted as muted by a different type of mobile terminal; and

receiving channel state information reference signals via the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals,

wherein a density, per antenna port of the mobile terminal, of the plurality of resource elements of the PRB allocated for the provision of channel state information reference signals for the mobile terminal is greater than a density, per antenna port of the different type of mobile terminal, of resource elements of the PRB that are allocated for channel state information reference signals for the different type of mobile terminal.

2. The method according to claim 1 , wherein some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals have identical positions within the PRB to resource elements of the PRB that are configured to be interpreted by the different type of mobile terminal as allocated for provision of channel state information reference signals for the different type of mobile terminal.

3. The method according to claim 1 , wherein each of the plurality of resource elements of the PRB that is allocated for the provision of channel state information reference signals has an identical position within the PRB to a respective resource element of the PRB that is configured to be interpreted by the different type of mobile terminal to be either muted or allocated for provision of channel state information reference signals for the different type of mobile terminal.

4. Apparatus for configuring resource elements for provision of channel state information reference signals, the apparatus comprising a processing system arranged to:

receive a definition of a plurality of resource elements of a physical resource block (PRB) to be allocated for the provision of channel state information reference signals for a mobile terminal, wherein at least some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals correspond in position to resource elements of the PRB that are configured to be interpreted as muted by a different type of mobile terminal; and

receive channel state information reference signals via the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals,

wherein a density, per antenna port of the mobile terminal, of the plurality of resource elements of the PRB allocated for the provision of channel state information reference signals for the mobile terminal is greater than a density, per antenna port of the different type of mobile terminal, of resource elements of the PRB that are allocated for channel state information reference signals for the different type of mobile terminal.

5. The apparatus according to claim 4 , wherein some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals have identical positions within the PRB to resource elements of the PRB that are configured to be interpreted by the different type of mobile terminal as allocated for provision of channel state information reference signals for the different type of mobile terminal.

6. The apparatus according to claim 4 , wherein each of the plurality of resource elements of the PRB that is allocated for the provision of channel state information reference signals has an identical position within the PRB to a respective resource element of the PRB that is configured to be interpreted by the different type of mobile terminal to be either muted by the different type of mobile terminal or allocated for provision of channel state information reference signals for the different type of mobile terminal.

7. The apparatus according claim 4 , wherein the apparatus comprises a mobile terminal.

8. The apparatus according to claim 7 , comprising a device interface configured to communicate with a base station in order to receive the definition of the plurality of resource elements of the PRB to be allocated for provision of channel state information reference signals.

9. The apparatus according to claim 7 , wherein the processing system is configured for use in a Long Term Evolution (LTE) system.

10. A method of configuring resource elements for provision of channel state information reference signals, the method comprising:

defining one or more first resource elements of a physical resource block (PRB) to be allocated for the provision of channel state information reference signals for a first type of mobile terminal;

defining one or more second resource elements of the PRB to be interpreted as muted by the first type of mobile terminal; and

defining a plurality of resource elements of the PRB to be allocated for provision of channel state information reference signals for a second type of mobile terminal,

wherein at least some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals for the second type of mobile terminal correspond in position to the second resource elements of the PRB, and

wherein a density, per antenna port of the second type of mobile terminal, of the plurality of resource elements of the PRB allocated for the provision of channel state information reference signals for the second type of mobile terminal is greater than a density, per antenna port of the first type of mobile terminal, of resource elements of the PRB that are allocated for channel state information reference signals for the first type of mobile terminal.

11. The method according to claim 10 , wherein some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals for the second type of mobile terminal have identical positions within the PRB to the first resource elements of the PRB.

12. The method according to claim 10 , wherein each of the plurality of resource elements of the PRB that is allocated for the provision of channel state information reference signals for the second type of mobile terminal has an identical position within the PRB to a respective one of the first or second resource elements of the PRB.

13. Apparatus for configuring resource elements for provision of channel state information reference signals, the apparatus comprising a processing system arranged to:

define one or more first resource elements of a physical resource block (PRB) to be allocated for the provision of channel state information reference signals for a first type of mobile terminal;

define one or more second resource elements of the PRB to be interpreted as muted by the first type of mobile terminal; and

define a plurality of resource elements of the PRB to be allocated for provision of channel state information reference signals for a second type of mobile terminal,

wherein at least some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals for the second type of mobile terminal correspond in position to the second resource elements of the PRB, and

wherein a density, per antenna port of the second type of mobile terminal, of the plurality of resource elements of the PRB allocated for the provision of channel state information reference signals for the second type of mobile terminal is greater than a density, per antenna port of the first type of mobile terminal, of resource elements of the PRB that are allocated for channel state information reference signals for the first type of mobile terminal.

14. The apparatus according to claim 13 , wherein some of the plurality of resource elements of the PRB that are allocated for the provision of channel state information reference signals for the second type of mobile terminal have identical positions within the PRB to the first resource elements of the PRB.

15. The apparatus according to claim 13 , wherein each of the plurality of resource elements of the PRB that is allocated for the provision of channel state information reference signals for the second type of mobile terminal has an identical position within the PRB to a respective one of the first or second resource elements of the PRB.

16. The apparatus according to claim 13 , wherein the processing system is arranged to define the plurality of resource elements of the PRB as interpreted by the second type of mobile terminal by spacing at least some of the resource elements uniformly within the PRB of the second type of mobile terminal.

17. The apparatus according to claim 13 , wherein the processing system is arranged to define the plurality of resource elements of the PRB as interpreted by the second type of mobile terminal by spacing at least some of the resource elements non-uniformly within the PRB of the second type of mobile terminal.

18. The apparatus according to claim 13 , wherein the apparatus comprises a base station.

19. The apparatus according to claim 18 , comprising a device interface configured to communicate with a plurality of mobile terminals including provision of definitions of the PRBs to the first and second types of mobile terminals.

20. The apparatus according to claim 18 , wherein the processing system is configured for use in a Long Term Evolution (LTE) system.