Methods and apparatus for reference signal design for interference cancellation

1. A method of wireless communication, comprising:

determining, by a base station based on at least one transmission characteristic of the base station of a plurality of transmission characteristics of the base station, one or more of a demodulation reference signal (DMRS) sequence including at least one DMRS symbol or a DMRS location pattern including a set of resource elements; and

transmitting, by the base station, a DMRS using at least one of the one or more of the DMRS sequence or the DMRS location pattern.

2. The method of claim 1 , wherein the plurality of transmission characteristics of the base station include one or more of:

a transmission mode, wherein the transmission mode includes at least a space frequency block coding (SFBC) mode and a non-SFBC mode;

a transmission waveform;

a transmission content; or

mini-slot partitioning structure used during transmission.

3. The method of claim 1 , wherein the determining the DMRS sequence includes determining different DMRS sequences for different DMRSs indicating different transmission characteristics of the base station, wherein the different DMRS sequences are orthogonal to each other and located in a same set of resource elements.

4. The method of claim 1 , wherein the one or more of the DMRS sequence or DMRS location pattern are determined to minimize cross-correlation within a transmission block by a user equipment (UE) receiving a transmission of the one or more of the DMRS sequence or the DMRS location pattern.

5. The method of claim 1 , wherein the determining the DMRS sequence includes determining different DMRS sequences for different resource blocks or resource block groups.

6. The method of claim 5 , wherein the determining the different DMRS sequences includes scaling the at least one symbol in the DMRS sequence by a phase, wherein the phase is associated with a resource block or a resource block group.

7. The method of claim 5 , wherein the determining the different DMRS sequences includes providing different DMRS sequences so that a same DMRS sequence is not used in multiple of one or more of resource blocks (RBs), resource block groups (RBGs), or precoding resource block groups (PRGs) to avoid an increase of peak-to-average power ratio (PAPR).

8. The method of claim 1 , wherein the determining the DMRS location pattern includes determining different DMRS location patterns for different DMRSs indicating different transmission characteristics, wherein the different DMRS location patterns do not overlap each other.

9. The method of claim 1 , further comprising transmitting one or more transmission parameters to another base station, wherein the one or more transmission parameters include one or more of:

a slot type;

a resource block group size;

a number of control symbols;

structure of mini-slot partitioning;

subcarrier spacing;

a cell identification (ID); or

a virtual cell ID.

10. The method of claim 9 , further comprising transmitting the one or more transmission parameters in a coordinated multi-point operation.

11. A method of wireless communication, comprising:

identifying, by a user equipment (UE), one or more of a demodulation reference signal (DMRS) sequence or a DMRS location pattern in a transmission from a first base station;

determining, by the UE, at least one transmission characteristic of the first base station of a plurality of transmission characteristics of the first base station based on the one or more of the DMRS sequence or the DMRS location pattern; and

performing, by the UE, interference cancellation for transmissions from the first base station.

12. The method of claim 11 , further comprising receiving one or more transmission parameters of the first base station from a second base station or the first base station, wherein the one or more transmission parameters include one or more of:

a slot type;

a resource block group size;

a number of control symbols;

structure of mini-slot partitioning;

subcarrier spacing;

a cell identification (ID); or

a virtual cell ID.

13. The method of claim 12 , further comprising receiving the one or more transmission parameters from the first base station in a coordinated multi-point operation.

14. The method of claim 12 , further comprising informing the second base station of transmission information desired for the interference cancellation from the first base station, wherein the transmission information includes one or more of: the one or more transmission parameters, or an indication of interference cancellation capabilities of the UE.

15. The method of claim 14 , wherein the informing the second base station of the transmission information includes signaling the transmission information to the second base station dynamically or semi-statically.

16. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured:

to determine, by a base station based on at least one transmission characteristic of the base station of a plurality of transmission characteristics of the base station, one or more of a demodulation reference signal (DMRS) sequence including at least one DMRS symbol or a DMRS location pattern including a set of resource elements; and

to transmit, by the base station, a DMRS using at least one of the one or more of the DMRS sequence or the DMRS location pattern.

17. The apparatus of claim 16 , wherein the plurality of transmission characteristics include one or more of:

a transmission mode, wherein the transmission mode includes at least a space frequency block coding (SFBC) mode and a non-SFBC mode;

a transmission waveform;

a transmission content; or

mini-slot partitioning structure used during transmission.

18. The apparatus of claim 16 , wherein the configuration of the at least one processor to determine the DMRS sequence includes configuration to determine different DMRS sequences for different DMRSs indicating different transmission characteristics of the base station, wherein the different DMRS sequences are orthogonal to each other and located in a same set of resource elements.

19. The apparatus of claim 16 , wherein the configuration of the at least one processor to determine one or more of the DMRS sequence or the DMRS location pattern are determined to minimize cross-correlation within a transmission block by a user equipment (UE) receiving a transmission of the one or more of the DMRS sequence or the DMRS location pattern.

20. The apparatus of claim 16 , wherein the configuration of the at least one processor to determine the DMRS sequence includes configuration to determine different DMRS sequences for different resource blocks or resource block groups.

21. The apparatus of claim 20 , wherein the configuration of the at least one processor to determine the different DMRS sequences includes configuration to scale the at least one symbol in the DMRS sequence by a phase, wherein the phase is associated with a resource block or a resource block group.

22. The apparatus of claim 20 , wherein the configuration of the at least one processor to determine the different DMRS sequences includes providing different DMRS sequences so that a same DMRS sequence is not used in multiple of one or more of resource blocks (RBs), resource block groups (RBGs), or precoding resource block groups (PRGs) to avoid an increase of peak-to-average power ratio (PAPR).

23. The apparatus of claim 16 , wherein the configuration of the at least one processor to determine the DMRS location pattern includes configuration to determine different DMRS location patterns for different DMRSs indicating different transmission characteristics, wherein the different DMRS location patterns do not overlap each other.

24. The apparatus of claim 16 , wherein the at least one processor is further configured to transmit one or more transmission parameters to another base station, wherein the one or more transmission parameters include one or more of:

a slot type;

a resource block group size;

a number of control symbols;

structure of mini-slot partitioning;

subcarrier spacing;

a cell identification (ID); or

a virtual cell ID.

25. The apparatus of claim 24 , wherein the at least one processor is further configured to transmit the one or more transmission parameters in a coordinated multi-point operation.

26. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured:

to identify, by a user equipment (UE), one or more of a demodulation reference signal (DMRS) sequence or a DMRS location pattern in a transmission from a first base station;

to determine, by the UE, at least one transmission characteristic of the first base station of a plurality of transmission characteristics of the first base station based on the one or more of the DMRS sequence or the DMRS location pattern; and

to perform, by the UE, interference cancellation for transmissions from the first base station.

27. The apparatus of claim 26 , wherein the at least one processor is further configured to receive one or more transmission parameters of the first base station from a second base station or the first base station, wherein the one or more transmission parameters include one or more of:

a slot type;

a resource block group size;

a number of control symbols;

structure of mini-slot partitioning;

subcarrier spacing;

a cell identification (ID); or

a virtual cell ID.

28. The apparatus of claim 27 , wherein the at least one processor is further configured to receive the one or more transmission parameters from the first base station in a coordinated multi-point operation.

29. The apparatus of claim 27 , wherein the at least one processor is further configured to inform the second base station of transmission information desired for the interference cancellation from the first base station, wherein the transmission information includes one or more of: the one or more transmission parameters, or an indication of interference cancellation capabilities of the UE.

30. The apparatus of claim 29 , wherein the configuration of the at least one processor to inform the second base station of the transmission information includes configuration to signal the transmission information to the second base station dynamically or semi-statically.