Interference measurement methods for advanced receiver in LTE/LTE-A
A method for receiving a PDCH is provided. The method comprises: receiving, by a UE, information identifying a plurality of resource elements that are transmitted with zero power in a resource block containing the PDCH; receiving, by the UE, a first DMRS on a first DMRS port transmitted from a first cell; and receiving, by the UE, the PDCH that is transmitted on the first DMRS port.
1. A method for estimating interference on a first downlink control channel, comprising:
receiving, by a user equipment (UE), the first downlink control channel transmitted from a first network node;
determining a first demodulation reference signal (DMRS) port associated with the first downlink control channel;
determining activity on a second DMRS port associated with one of a second downlink control channel and a physical downlink shared channel (PDSCH); and
estimating the interference on the first downlink control channel based on the second DMRS port,
wherein the second DMRS port is orthogonal to the first DMRS port, and
wherein orthogonality between the first DMRS port and the second DMRS port is maintained using an enhanced physical downlink control channel (EPDCCH) ID.
2. The method of claim 1 , wherein determining activity on the second DMRS port comprises determining whether an energy level detected on the second DMRS port exceeds a threshold.
3. The method of claim 1 , wherein the first downlink control channel is an enhanced physical downlink control channel (EPDCCH).
4. The method of claim 1 , wherein orthogonality between the second DMRS port and the first DMRS port is further maintained by using a same cell identifier (ID) and a same scrambling ID to initialize pseudo-random sequences for DMRSs corresponding to the first and second DMRS ports.
5. The method of claim 1 , wherein orthogonality between the first DMRS port and the second DMRS port is further maintained according to at least one of a cell identifier (ID), a scrambling ID, or a virtual cell identifier (ID).
6. The method of claim 1 , further comprising receiving one or more identifiers (IDs) corresponding to DMRS sequences, wherein each ID is associated with one cell in a network.
7. The method of claim 6 , wherein the interference on the first downlink control channel is estimated according to an ID corresponding to a DMRS sequence associated with the second DMRS port.
8. The method of claim 1 , wherein the first downlink control channel is associated with at least one resource element (RE) reserved for interference measurement.
9. The method of claim 1 , further comprising performing interference cancellation on at least a portion of the estimated interference.
10. A non-transitory, tangible computer readable storage medium encoded with computer executable instructions, wherein execution of the computer executable instructions is for:
receiving, from a first network node, a physical downlink channel;
determining a demodulation reference signal (DMRS) port having a relationship to the physical downlink channel; and
estimating an amount of interference on the physical downlink channel based at least in part on the DMRS port,
wherein the first DMRS port and the second DMRS port are orthogonal DMRS ports, and
wherein orthogonality between the first DMRS port and the second DMRS port is maintained using an enhanced physical downlink control channel (EPDCCH) ID.
11. The non-transitory, tangible computer readable storage medium of claim 10 , wherein determining the DMRS port having the relationship to the physical downlink channel comprises determining the DMRS port as a first DMRS port for use in demodulating the physical downlink channel, and wherein estimating the amount of interference on the physical downlink channel based at least in part on the DMRS port comprises estimating the interference based at least in part on activity on a second DMRS port associated with a second physical downlink channel.
12. The non-transitory, tangible computer readable storage medium of claim 10 , wherein orthogonality between the first DMRS port and the second DMRS port is further maintained by using at least one of a same cell identifier (ID) or a same scrambling ID to initialize pseudo-random sequences for DMRSs corresponding to the first and second DMRS ports.
13. The non-transitory, tangible computer readable storage medium of claim 10 , wherein estimating the amount of interference on the physical downlink channel is further based, at least in part, on at least one of cell identifier (ID), a scrambling ID, an enhanced physical downlink control channel (EPDCCH) ID, a DMRS sequence, or an aggregation level.
14. The non-transitory, tangible computer readable storage medium of claim 10 , wherein the processor is further configured to perform interference cancellation on at least a portion of the estimated interference.