Method and apparatus for transmitting and receiving channel state information reference signal in full dimension MIMO wireless communication system

1. A method for transmitting a Channel State Information-Reference Signal (CSI-RS) by a base station, the method comprising:

generating a first information representing a number of antenna ports;

generating a second information representing a CSI-RS resource allocation, the CSI-RS resource allocation including a CSI-RS configuration indicating a location of a CSI-RS resource;

when a total number of antenna ports used for transmission of CSI-RS is greater than a maximum number of antenna ports which the first information is able to represent:

generating a third information representing one or more additional CSI-RS resource allocations, wherein each of one or more additional CSI-RS resource allocations includes a corresponding CSI-RS configuration indicating a location of a corresponding CSI-RS resource, and

transmitting, to a User Equipment (UE), the first information, the second information, and the third information without explicitly signaling the total number antenna ports used for transmission of CSI-RS and without explicitly signaling a total number of CSI-RS resources;

generating a reference sequence for the CSI-RS, the reference sequence including a pseudo random sequence;

mapping the reference sequences on the CSI-RS resources; and

transmitting, to the UE, the CSI-RS including the mapped reference sequence through the CSI RS resources,

wherein a total number of antenna ports used for transmission of CSI-RS is determined based on the first information, the second information, and the third information.

2. The method of claim 1 , wherein the total number of antenna ports used for transmission of the CSI-RS is obtained based on the number of antenna ports represented by the first information and the total number of CSI-RS resources indicated by the second information and the third information.

3. The method of claim 2 , wherein the total number of CSI-RS resources is the same as a number of CSI-RS resource allocations included in the second and third informations.

4. The method of claim 3 , wherein the total number of CSI-RS resources is obtained according to the number of CSI-RS resource allocations included in the second information and the third information.

5. The method of claim 2 , wherein the total number of CSI-RS resources is implicitly indicated by the second information and the third information.

6. The method of claim 2 , wherein a number of antenna ports corresponding to a first CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information is an integer multiple of a number of antenna ports corresponding to a second CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information.

7. The method of claim 6 , wherein the number of antenna ports corresponding to the first CSI-RS configuration doubles the number of antenna ports corresponding to the second CSI-RS configuration.

8. The method of claim 2 , wherein a number of antenna ports corresponding to a first CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information is an integer multiple of a predetermined number.

9. The method of claim 2 , wherein the total number of antenna ports used for transmission of CSI-RS is divided into a plurality of antenna port groups and each of the plurality of antenna port groups is assigned to a corresponding CSI-RS resource.

10. The method of claim 9 , wherein the number of CSI-RS resources is the same as the number of the plurality of antenna port groups.

11. The method of claim 2 , wherein the maximum number of antenna ports which the first information is able to represent is 8, and

when the total number of antenna ports used for transmission of CSI-RS is 16, the number of antenna ports represented by the first information is 8 and the total number of the CSI-RS resources indicated by the second information and the third information is 2, and

when the total number of antenna ports used for transmission of CSI-RS is 32, the number of antenna ports represented by the first information is 8 and the total number of the CSI-RS resources indicated by the second information and the third information is 4.

12. The method of claim 2 , wherein the pseudo random sequence is initialized with a value, the value being determined based on an identifier for the CSI-RS.

13. The method of claim 12 , wherein the identifier for the CSI-RS is identical to a cell identifier assigned to a cell which the UE belongs to when the identifier for the CSI-RS is not signaled.

14. A method for reporting channel state information by a user equipment, the method comprising:

receiving, from a base station, a first information representing a number of antenna ports;

receiving, from the base station, a second information representing a Channel State Information Reference Signal (CSI-RS) resource allocation, wherein the CSI-RS resource allocation includes a CSI-RS configuration indicating a location of a CSI-RS resource;

when a total number of antenna ports used for transmission of CSI-RS is greater than a maximum number of antenna ports which the first information is able to represent, receiving, from the base station, a third information representing one or more additional CSI-RS resource allocations, wherein each of one or more additional CSI-RS resource allocations includes a corresponding CSI-RS configuration indicating a location of a corresponding CSI-RS resource;

receiving, from the base station, CSI-RS including a reference sequence through CSI-RS resources;

obtaining a total number of antenna ports used for transmission of CSI-RS based on the first information, the second information and the third information, wherein neither the total number of antenna ports used for transmission of CSI-RS nor the total number of CSI-RS resources is explicitly signaled from the base station;

generating channel state information using the reference sequence received on the CSI-RS resources; and

reporting the channel state information to the base station.

15. The method of claim 14 , wherein the total number of antenna ports used for transmission of CSI-RS is obtained based on the number of antenna ports represented by the first information and the total number of CSI-RS resources indicated by the second information and the third information.

16. The method of claim 15 , wherein the total number of CSI-RS resources is the same as a number of CSI-RS resource allocations included in the second information and the third information.

17. The method of claim 16 , wherein the total number of CSI-RS resources is obtained by the number of CSI-RS resource allocations included in the second information and the third information.

18. The method of claim 15 , wherein the total number of CSI-RS resources is implicitly indicated by the second information and the third information.

19. The method of claim 15 , wherein a number of antenna ports corresponding to a first CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information is an integer multiple of a number of antenna ports corresponding to a second CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information.

20. The method of claim 19 , wherein the number of antenna ports corresponding to the first CSI-RS configuration doubles the number of antenna ports corresponding to the second CSI-RS configuration.

21. The method of claim 15 , wherein a number of antenna ports corresponding to a first CSI-RS configuration among CSI-RS configurations indicated by the second information and the third information is an integer multiple of a predetermined number.

22. The method of claim 15 , wherein the total number of antenna ports used for transmission of CSI-RS is divided into a plurality of antenna port groups and each of the plurality of antenna port groups is assigned to a corresponding CSI-RS resource.

23. The method of claim 22 , wherein the number of CSI-RS resources is the same as the number of the plurality of antenna port groups.

24. The method of claim 15 , wherein the maximum number of antenna ports which the first information is able to represent is 8, and

when the total number of antenna ports used for transmission of CSI-RS is 16, the number of antenna ports represented by the first information is 8 and the total number of the CSI-RS resources indicated by the second information and the third information is 2, and

when the total number of antenna ports used for transmission of CSI-RS is 32, the number of antenna ports represented by the first information is 8 and the total number of the CSI-RS resources indicated by the second information and the third information is 4.

25. The method of claim 15 , wherein the pseudo random sequence is initialized with a value, the value is determined based on an identifier for the CSI-RS.