Reference signal for a control channel in wireless communication network

1. A method in a wireless communication terminal, the method comprising:

receiving a first set of pilot signal resource elements and control information in one or more spatial layers in a first set of time symbols in a first resource block in a subframe, the first resource block spanning a set of time symbols in a sub frame and a first set of frequency carriers in the sub-frame;

receiving a second set of pilot signal resource elements and data in one or more spatial layers in the first set of time symbols in a second resource block in the subframe, the second resource block spanning the set of time symbols in the sub frame and a second set of frequency carriers in the sub-frame;

decoding the one or more spatial layers in which the control information is received using the first set of pilot signal resource elements, the first set of pilot signal resource elements comprising a first number of pilot signal resource elements per layer;

and decoding the one or more spatial layers in which the data are received in the second resource block using the second set of pilot signal resource elements, the second set of pilot signal resource elements comprising a second number of pilot signal resource elements per layer, the second number of pilot signal resource elements present in the second resource block;

wherein the first number is greater than the second number;

receiving a third set of pilot signal resource elements and data in one or more spatial layers in a third resource block in the subframe, the third resource block spanning a second set of time symbols in the sub-frame and the first set of frequency carriers in the sub-frame; and

decoding the one or more spatial layers in which the data are received in the third resource block using the third set of pilot signal resource elements, the third set of pilot signal resource elements comprising a third number of pilot signal resource elements per layer wherein the third number is at least equal to the first number;

wherein the second set of time symbols in the sub-frame is different from the first set of time symbols in the subframe.

2. The method of claim 1 :

wherein the first number of pilot signal resource elements per layer is a first number of pilot signal resource elements per layer per resource block; and

wherein the second number of pilot signal resource elements per layer is a second number of pilot signal resource elements per layer per resource block.

3. The method of claim 1 wherein the second set of frequency carriers are non-overlapping with the first set of frequency carriers.

4. The method of claim 1 wherein a size of the second set of frequency carriers is same as a size of the first set of frequency carriers.

5. The method of claim 1 further comprising decoding the one or more spatial layers in which the control information is received using the first set of pilot signal resource elements includes performing channel estimation based on the first set of pilot resource elements.

6. The method of claim 1 wherein the third number is equal to twice the first number.

7. The method of claim 1 further comprising:

decoding a spatial layer in which the control information is received using the first set of pilot signal resource elements, the first set of pilot signal resource elements associated with a first antenna port; and

decoding a spatial layer in which the data are received using a second set of pilot signal resource elements, the second set of pilot signal resource elements associated with the first antenna port.

8. The method of claim 7 wherein the first set of pilot signal resource elements and the second set of pilot signal resource elements occupy common time symbols in the subframe.

9. The method of claim 7 further comprising receiving control information using only the first set of pilot signal resource elements.

10. The method of claim 1 further comprising:

decoding a spatial layer in which the control information is received using the first set of pilot signal resource elements, the first set of pilot signal resource elements associated with a first antenna port and a second antenna port; and

decoding a spatial layer in which the data are received using the second set of pilot signal resource elements, the second set of pilot signal resource elements associated with a third antenna port.

11. The method of claim 10 wherein the first set of pilot signal resource elements and the second set of pilot signal resource elements occupy common time symbols in the subframe.

12. The method of 10 wherein the first antenna port is the same as the third antenna port.

13. The method of claim 1 further comprising:

determining that data are expected in the second resource block in the subframe using the control information; and

decoding the one or more spatial layers in which the data are received in the second resource block using the control information.

14. The method of claim 1 further comprising determining that control information is expected in the first resource block in the subframe based on a signal received from a base unit.