Hybrid dedicated reference signal method and system
The transmission and decoding of resource blocks (RBs) transmitted via a multiple-input multiple-output (MIMO) antenna having a plurality of transmit antennas is disclosed. Each RB includes a plurality of resource elements (REs). Each RE is reserved for one of a common reference signal (CRS) associated with one of the transmit antennas, a dedicated reference signal (DRS) including a single beamformed or precoded pilot, a DRS including a composite beamformed or precoded pilot, and a data symbol. Each RB may include a “control type” data symbol that indicates a DRS mode associated with the RB. In one DRS mode, each DRS includes a single beamformed or precoded pilot. In another DRS mode, each DRS includes a composite beamformed or precoded pilot. In yet another DRS mode, single beamformed or precoded pilots, and composite beamformed or precoded pilots, may coexist and be transmitted simultaneously within the same RBs or in different RBs.
1. A method implemented in a wireless transmit/receive unit (WTRU), the method comprising:
receiving multiple resource blocks (RBs), wherein:
each resource block (RB) of the multiple RBs comprises multiple resource elements (REs);
the REs comprise one or more data symbols, one or more control-type data symbols, and one or more dedicated reference signals (DRSs) specific to a single WTRU;
the control-type data symbols comprise a DRS mode indicator signaling any of multiple DRS modes;
in a first DRS mode of the multiple DRS modes, a first configuration of the REs is used for the DRSs and the DRSs comprise single beamformed or precoded pilots; and
in a second DRS mode of the multiple DRS modes, a second configuration of the REs is used for the DRSs and the DRSs comprises composite beamformed or precoded pilots;
determining, based on the signaled DRS mode, which of the REs include the DRSs;
estimating a channel response based on the DRSs; and
decoding data in the data symbols based on the estimated channel response.
2. The method of claim 1 , wherein each DRS mode of the multiple DRS modes is indicative of a number of transmission layers.
3. The method of claim 1 , wherein one or more RBs of the multiple RBs comprises the control-type data symbols that include the DRS mode indicator.
4. The method of claim 1 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots; and
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots.
5. The method of claim 1 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots;
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots; and
the REs of a third RB of the multiple RBs lack DRSs.
6. The method of claim 1 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
a first group of the REs is reserved for the DRSs formed as single beamformed or precoded pilots; and
a second group of the REs is reserved for the DRSs formed as composite beamformed or precoded pilots.
7. The method of claim 1 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs; and
the DRSs comprise a combination of a single beamformed or precoded pilot and a composite beamformed or precoded pilot.
8. The method of claim 1 , wherein, in a third DRS mode of the multiple DRS modes:
the one or more DRSs are multiple DRSs; and
the multiple DRSs comprise at least one single beamformed or precoded pilot and at least one composite beamformed or precoded pilot.
9. The method of claim 1 , wherein the DRS mode indicator indicates a change in DRS mode.
10. The method of claim 1 , wherein the first DRS mode is indicative of a single transmission layer.
11. The method of claim 1 , wherein the second DRS mode is indicative of a plurality of transmission layers.
12. The method of claim 1 , further comprising: receiving the DRS mode indicator.
13. A wireless transmit/receive unit (WTRU) comprising:
a multiple-input multiple-output (MIMO) antenna configured to receive multiple resource blocks (RBs), wherein:
each resource block (RB) of the multiple RBs comprises multiple resource elements (REs);
the REs comprise one or more data symbols, one or more control-type data symbols, and one or more dedicated reference signals (DRSs) specific to a single WTRU;
the control-type data symbols comprise a DRS mode indicator signaling any of multiple DRS modes;
in a first DRS mode of the multiple DRS modes, a first configuration of REs is used for the DRSs and the DRSs comprise single beamformed or precoded pilots; and
in a second DRS mode of the multiple DRS modes, a second configuration of the REs is used for the DRSs and the DRSs comprise composite beamformed or precoded pilots;
a signal parsing unit configured to determine, based on the signaled DRS mode, which of the REs include the DRSs;
a channel estimation unit configured to estimate a channel response based on the DRSs; and
a data decoding unit configured to decode data in the data symbols based on the estimated channel response.
14. The WTRU of claim 13 , wherein each DRS mode of the multiple DRS modes is indicative of a number of transmission layers.
15. The WTRU of claim 13 , wherein one or more RBs of the multiple RBs comprises the control-type data symbols that include the DRS mode indicator.
16. The WTRU of claim 13 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots; and
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots.
17. The WTRU of claim 13 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots;
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots; and
the REs of a third RB of the multiple RBs lack DRSs.
18. The WTRU of claim 13 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
a first group of the REs is reserved for the DRSs formed as single beamformed or precoded pilots; and
a second group of the REs is reserved for the DRSs formed as composite beamformed or precoded pilots.
19. The WTRU of claim 13 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs; and
the DRSs comprise a combination of a single beamformed or precoded pilot and a composite beamformed or precoded pilot.
20. The WTRU of claim 13 , wherein, in a third DRS mode of the multiple DRS modes:
the one or more DRSs are multiple DRSs; and
the multiple DRSs comprise at least one single beamformed or precoded pilot and at least one composite beamformed or precoded pilot.
21. The WTRU of claim 13 , wherein the DRS mode indicator indicates a change in DRS mode.
22. The WTRU of claim 13 , wherein the data detection unit is configured to decode the DRS mode indicator from the one or more control-type data symbols based on an estimated common channel response or an estimated effective channel response.
23. The WTRU of claim 22 , wherein the REs comprise one or more common reference signals (CRSs) for a plurality of WTRUs, and wherein the channel estimation unit is configured to estimate the estimated common channel response based on the CRSs.
24. A wireless transmit/receive unit (WTRU) comprising: a processor and a receiver, wherein:
the receiver is configured to receive multiple resource blocks (RBs);
each resource block (RB) of the multiple RBs comprises multiple resource elements (REs);
the REs comprise one or more data symbols, one or more control-type data symbols, and one or more dedicated reference signals (DRSs) specific to a single WTRU;
the control-type data symbols comprise a DRS mode indicator signaling any of a plurality of DRS modes;
in a first DRS mode of the multiple DRS modes, a first configuration of REs is used for the DRSs and the DRSs comprise single beamformed or precoded pilots; and
in a second DRS mode of the multiple DRS modes, a second configuration of the REs is used for the DRSs and the DRSs comprise composite beamformed or precoded pilots;
the processor is configured to:
determine, based on the signaled DRS mode, which of the REs include the DRSs;
estimate a channel response based on the DRSs; and
decode data in the data symbols based on the estimated channel response.
25. The WTRU of claim 24 , wherein each DRS mode of the multiple DRS modes is indicative of a number of transmission layers.
26. The WTRU of claim 24 , wherein one or more RBs of the multiple RBs comprise the control-type data symbols that include the DRS mode indicator.
27. The WTRU of claim 24 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots; and
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots.
28. The WTRU of claim 24 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
the DRSs of a first RB of the multiple RBs comprise single beamformed or precoded pilots;
the DRSs of a second RB of the multiple RBs comprise composite beamformed or precoded pilots; and
the REs of a third RB of the multiple RBs lack DRSs.
29. The WTRU of claim 24 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs;
a first group of the REs is reserved for the DRSs formed as single beamformed or precoded pilots; and
a second group of the REs is reserved for the DRSs formed as composite beamformed or precoded pilots.
30. The WTRU of claim 24 , wherein, in a third DRS mode of the multiple DRS modes:
a third configuration of the REs is used for the DRSs; and
the DRSs comprise a combination of a single beamformed or precoded pilot and a composite beamformed or precoded pilot.
31. The WTRU of claim 24 , wherein, in a third DRS mode of the multiple DRS modes:
the one or more DRSs are multiple DRSs; and
the multiple DRSs comprise at least one single beamformed or precoded pilot and at least one composite beamformed or precoded pilot.
32. The WTRU of claim 24 , wherein each DRS mode of the multiple DRS modes is indicative of a number of transmission layers.
33. The WTRU of claim 24 , wherein one or more RBs of the multiple RBs comprise the control-type data symbols that include the DRS mode indicator.
34. The WTRU of claim 24 , wherein the DRS mode indicator indicates a change in DRS mode.