Demodulation reference signaling in LTE/NR coexistence

1. A method of operating a network node, the network node operating according to a first radio access technology, RAT, the method comprising:

transmitting data in a transmission resource structure, the transmission resource structure comprising a first set of resource elements for data and a second set of resource elements for demodulation reference signals, DMRS, the second set representing at least one pattern in a frequency domain, the transmission resource structure comprising the second set of resource elements for demodulation reference signals that represents at least one pattern in a frequency domain and being scheduled based on a coexistence indication, the transmission resource structure scheduled such that at least one of patterns and locations are selected that shift DMRS in time relative to locations of cell-specific reference signals according to a second RAT, the coexistence indication indicating the presence of cell-specific reference signals associated to the second RAT and the coexistence indication representing the network node's awareness that operation may occur according to the second RAT.

2. The method according to claim 1 , wherein the first RAT corresponds to New Radio, NR technology, and the second RAT corresponds to Long Term Evolution, LTE, technology.

3. The method according to claim 1 , wherein the transmission resource structure is scheduled to have a duration in symbol time intervals based on the coexistence indication.

4. The method according to claim 1 , wherein the second set is based on a duration in symbol time intervals of the transmission resource structure.

5. The method according to claim 1 , wherein the first set is punctured in frequency space.

6. The method according to claim 1 , wherein the transmission resource structure comprises a third set of resource elements puncturing the first set.

7. The method according to claim 1 , wherein the transmission resource structure has an end symbol that is arranged in a symbol before an end symbol of a slot.

8. The method according to claim 1 , wherein in a slot in which the data is transmitted, there are scheduled channel state information reference signals after the transmission resource structure.

9. A network node configured for operating according to a first radio access technology, RAT, the network node being configured to transmit data in a transmission resource structure, the transmission resource structure comprising a first set of resource elements for data and a second set of resource elements for demodulation reference signals, DMRS, the second set representing at least one pattern in a frequency domain, the transmission resource structure comprising the second set of resource elements for demodulation reference signals that represents at least one pattern in a frequency domain and being scheduled based on a coexistence indication, the transmission resource structure scheduled such that at least one of patterns and locations are selected that shift DMRS in time relative to locations of cell-specific reference signals according to a second RAT, the coexistence indication indicating the presence of cell-specific reference signals associated to the second RAT and the coexistence indication representing the network node's awareness that operation may occur according to the second RAT.

10. The network node according to claim 9 , wherein the first RAT corresponds to New Radio, NR technology, and the second RAT corresponds to Long Term Evolution, LTE, technology.

11. The network node according to claim 9 , wherein the transmission resource structure is scheduled to have a duration in symbol time intervals based on the coexistence indication.

12. The network node according to claim 9 , wherein the second set is based on a duration in symbol time intervals of the transmission resource structure.

13. The network node according to claim 9 , wherein the first set is punctured in frequency space.

14. The network node according to claim 9 , wherein the transmission resource structure comprises a third set of resource elements puncturing the first set.

15. The network node according to claim 9 , wherein the transmission resource structure has an end symbol that is arranged in a symbol before an end symbol of a slot.

16. The network node according to claim 9 , wherein in a slot in which the data is transmitted, there are scheduled channel state information reference signals after the transmission resource structure.

17. A method of operating a user equipment, the user equipment operating according to a first radio access technology, RAT, the method comprising:

receiving data based on a transmission resource structure, the transmission resource structure comprising a first set of resource elements for data and a second set of resource elements for demodulation reference signals, DMRS, the second set representing a pattern in a frequency domain, and the transmission resource structure scheduled such that at least one of patterns and locations are selected that shift DMRS in time relative to locations of cell-specific reference signals according to a second RAT, receiving comprising associating signaling on resource elements of the transmission resource structure comprising the second set of resource elements for demodulation reference signals that represents at least one pattern in a frequency domain to the first set based on a coordination indication indicating the presence of cell-specific reference signals associated to the second RAT, the coordination indication determined by the user equipment based on at least one of measurements of signaling typical for the second RAT and reading from a memory.

18. The method according to claim 17 , wherein the first RAT corresponds to New Radio, NR technology, and the second RAT corresponds to Long Term Evolution, LTE, technology.

19. A user equipment configured to operate according to a first radio access technology, RAT, the user equipment being configured to receive data based on a transmission resource structure, the transmission resource structure comprising a first set of resource elements for data and a second set of resource elements for demodulation reference signals, DMRS, the second set representing a pattern in a frequency domain, and the transmission resource structure scheduled such that at least one of patterns and locations are selected that shift DMRS in time relative to locations of cell-specific reference signals according to a second RAT, receiving comprising associating signaling on resource elements of the transmission resource structure comprising the second set of resource elements for demodulation reference signals that represents at least one pattern in a frequency domain to the first set based on a coordination indication indicating the presence of cell-specific reference signals associated to the second RAT, the coordination indication determined by the user equipment based on at least one of measurements of signaling typical for the second RAT and reading from a memory.

20. A non-transitory computer storage medium storing an executable program comprising instructions configured to cause processing circuitry to at least one of control and perform a method of operating a network node, the network node operating according to a first radio access technology, RAT, the method comprising:

transmitting data in a transmission resource structure, the transmission resource structure comprising a first set of resource elements for data and a second set of resource elements for demodulation reference signals, DMRS, the second set representing at least one pattern in a frequency domain, the transmission resource structure comprising the second set of resource elements for demodulation reference signals that represents at least one pattern in a frequency domain and being scheduled based on a coexistence indication, the transmission resource structure scheduled such that at least one of patterns and locations are selected that shift DMRS in time relative to locations of cell-specific reference signals according to a second RAT, the coexistence indication indicating the presence of cell-specific reference signals associated to the second RAT and the coexistence indication representing the network node's awareness that operation may occur according to the second RAT.