Method and apparatus for signaling to support flexible reference signal configuration

1. A method for signaling a reference signal, the method comprising:

determining which of a plurality of physical resource elements associated with a physical resource block are to include the reference signal such that a variable number or combination of one or more physical resource elements of the physical resource block are determined from any of the plurality of physical resource elements to include the reference signal without any restriction on a position of the one or more physical resource elements within the physical resource block;

generating a signaling message including information indicating the variable number or combination of the one or more physical resource elements of the physical resource block that are determined from the plurality of physical resource elements to include the reference signal, wherein the signaling message includes,

one or more frequency-domain bitmaps corresponding to the physical resource block and indicating which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal, and

a time-domain symbol map including one or more symbols corresponding to one or more subframes and indicating (i) which of the one or more subframes will contain the reference signal, and (ii) which frequency-domain bitmap of the one or more frequency-domain bitmaps is applicable in each subframe of the one or more subframes; and

transmitting the signaling message to at least one user equipment to inform the at least one user equipment as to which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal.

2. The method of claim 1 , wherein the one or more physical resource elements are associated with one or more physical resource blocks.

3. The method of claim 2 , wherein the one or more frequency-domain bitmaps correspond to the one or more physical resource blocks and indicate which of the one or more physical resource blocks will contain the reference signal.

4. The method of claim 3 , wherein each respective frequency-domain bitmap of the one or more frequency domain bitmaps further indicates to which of one or more types of reference signals the respective frequency-domain bitmap applies for each subframe of the one or more subframes.

5. The method of claim 1 , wherein at least one of (i) the one or more frequency-domain bitmaps and (ii) the one or more symbols of the time-domain symbol map indicate different frequency-domain configurations for different types of reference signals.

6. The method of claim 5 , wherein each respective frequency-domain bitmap of the one or more frequency-domain bitmaps further indicates to which of one or more types of reference signals the respective frequency-domain bitmap applies for each subframe of the one or more subframes.

7. The method of claim 1 , wherein each respective frequency-domain bitmap of the one or more frequency-domain bitmaps further indicates to which of one or more types of reference signals the respective frequency-domain bitmap applies for each subframe of the one or more subframes.

8. The method of claim 1 , further comprising:

determining a mode associated with transmission of the signaling message, wherein the determined mode is one of a broadcast mode and a dedicated mode; and

transmitting the signaling message to the at least one user equipment using the determined mode.

9. A method for using a reference signal, the method comprising:

receiving a signaling message including information indicating which of a plurality of physical resource elements associated with a physical resource block are to include the reference signal, wherein a variable number or combination of one or more physical resource elements of the physical resource block are determined from any of the plurality of physical resource elements to include the reference signal without any restriction on a position of the one or more physical resource elements within the physical resource block, wherein the signaling message includes,

one or more frequency-domain bitmaps corresponding to the physical resource block and indicating which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal, and

a time-domain symbol map including one or more symbols corresponding to one or more subframes and indicating (i) which of the one or more subframes will contain the reference signal, and (ii) which frequency-domain bitmap of the one or more frequency-domain bitmaps is applicable in each subframe of the one or more subframes;

determining the variable number or combination of the one or more physical resource elements that will contain the reference signal based on the signaling message; and

using the reference signal contained in at least one of the one or more physical resource elements for at least one of detection, synchronization and one or more measurements of a carrier.

10. The method of claim 9 , wherein the one or more physical resource elements are associated with one or more physical resource blocks, and the one or more frequency-domain bitmaps correspond to the one or more physical resource blocks and indicate which of the one or more physical resource blocks will contain the reference signal.

11. The method of claim 9 , wherein at least one of (i) the one or more frequency-domain bitmaps and (ii) the one or more symbols of the time-domain symbol map indicate different frequency-domain configurations for different types of reference signals.

12. The method of claim 9 , wherein each respective frequency-domain bitmap of the one or more frequency-domain bitmaps further indicates whether the respective frequency-domain bitmap for each subframe of the one or more subframes applies to one or more of Cell-Specific Reference Signals (CRS) and Channel State Information Reference Signals (CSI-RS).

13. The method of claim 9 , wherein receiving the signaling message includes receiving the signaling message over one of a dedicated channel associated with a carrier and a broadcast channel.

14. A network element comprising:

a processor configured to,

determine which of a plurality of physical resource elements associated with a physical resource block are to include a reference signal such that a variable number or combination of one or more physical resource elements of the physical resource block are determined from any of the plurality of physical resource elements—to include the reference signal without any restriction on a position of the one or more physical resource elements within the physical resource block,

generate a signaling message including information indicating the variable number or combination of the one or more physical resource elements of the physical resource block that are determined from the plurality of physical resource elements to include the reference signal, wherein the signaling message includes,

one or more frequency-domain bitmaps corresponding to the physical resource block and indicating which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal, and

a time-domain symbol map including one or more symbols corresponding to one or more subframes and indicating (i) which of the one or more subframes will contain the reference signal, and (ii) which frequency-domain bitmap of the one or more frequency-domain bitmaps is applicable in each subframe of the one or more subframes, and

transmit the signaling message to at least one user equipment to inform the at least one user equipment as to which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal.

15. A user equipment comprising:

a processor configured to,

receive a signaling message including information indicating which of a plurality of physical resource elements associated with a physical resource block are to include a reference signal, wherein a variable number or combination of one or more physical resource elements of the physical resource block are determined from any of the plurality of physical resource elements to include the reference signal without any restriction on a position of the one or more physical resource elements within the physical resource block, wherein the signaling message includes,

one or more frequency-domain bitmaps corresponding to the physical resource block and indicating which of the plurality of physical resource elements associated with the physical resource block will contain the reference signal, and

a time-domain symbol map including one or more symbols corresponding to one or more subframes and indicating (i) which of the one or more subframes will contain the reference signal, and (ii) which frequency-domain bitmap of the one or more frequency-domain bitmaps is applicable in each subframe of the one or more subframes,

determine the variable number or combination of the one or more physical resource elements that will contain the reference signal based on the signaling message; and

use the reference signal contained in at least one of the one or more physical resource elements for at least one of detection, synchronization and one or more measurements of a carrier.