Coexistence of reference signals in wireless communication networks

1. A method in a radio network node, the radio network node operating according to a first radio access technology and a second radio access technology, the first and second radio access technologies using a same subcarrier spacing, the method comprising:

transmitting an indication to a wireless device indicating that the first radio access technology and the second radio access technology are coexisting on a same carrier, the indication being a parameter in an information element of a Radio Resource Control, RRC, message;

transmitting a downlink transmission to the wireless device operating according to the first radio access technology, the downlink transmission including reference signals of the first radio access technology, the reference signals of the first radio access technology being located at a first symbol location within the downlink transmission when the reference signals of the first radio access technology are determined not to collide with reference signals of the second radio access technology, and the reference signals of the first radio access technology being located at a second symbol location within the downlink transmission when the reference signals of the first radio access technology are determined to collide with the reference signals of the second radio access technology, the second symbol location being either before the first symbol location or after the first symbol location.

2. The method of claim 1 , wherein the parameter is a lte-CRS-ToMatchAround parameter.

3. The method of claim 1 , wherein the second symbol location is either at least one symbol before the first symbol location or at least one symbol after the first symbol location.

4. The method of claim 1 , wherein the reference signals of the first radio access technology are demodulation reference signals, DMRS.

5. The method of claim 1 , wherein the reference signals of the second radio access technology are common or cell reference signals, CRS.

6. A radio network node configured to operate according to a first radio access technology and a second radio access technology, the first and second radio access technologies using a same subcarrier spacing, the radio network node adapted to:

transmit an indication to a wireless device indicating that the first radio access technology and the second radio access technology are coexisting on a same carrier, the indication being a parameter in an information element of a Radio Resource Control, RRC, message:

transmit a downlink transmission to the wireless device operating according to the first radio access technology, the downlink transmission including reference signals of the first radio access technology, the reference signals of the first radio access technology being located at a first symbol location within the downlink transmission when the reference signals of the first radio access technology are determined not to collide with reference signals of the second radio access technology, and the reference signals of the first radio access technology being located at a second symbol location within the downlink transmission when the reference signals of the first radio access technology are determined to collide with the reference signals of the second radio access technology, the second symbol location being either before the first symbol location or after the first symbol location.

7. The radio network node of claim 6 , wherein the parameter is a lte-CRS-ToMatchAround parameter.

8. The radio network node of claim 6 , wherein the second symbol location is either at least one symbol before the first symbol location or at least one symbol after the first symbol location.

9. The radio network node of claim 6 , wherein the reference signals of the first radio access technology are demodulation reference signals, DMRS.

10. The radio network node of claim 6 , wherein the reference signals of the second radio access technology are common or cell reference signals, CRS.

11. A method in a wireless device, the wireless device operating according to a first radio access technology, the method comprising:

receiving an indication from a radio network node operating according to the first radio access technology and to a second radio access technology, the first and second radio access technologies using a same subcarrier spacing, the indication indicating that the first radio access technology and the second radio access technology are coexisting on a same carrier, the indication being a parameter in an information element of a Radio Resource Control, RRC, message:

receiving a downlink transmission from the radio network node, the downlink transmission including reference signals of the first radio access technology, the reference signals of the first radio access technology being located at a first symbol location within the downlink transmission when the reference signals of the first radio access technology are determined not to collide with reference signals of the second radio access technology, and the reference signals of the first radio access technology being located at a second symbol location within the downlink transmission when the reference signals of the first radio access technology are determined to collide with the reference signals of the second radio access technology, the second symbol location being either before the first symbol location or after the first symbol location.

12. The method of claim 11 , wherein the parameter is a lte-CRS-ToMatchAround parameter.

13. The method of claim 11 , wherein the second symbol location is either at least one symbol before the first symbol location or at least one symbol after the first symbol location.

14. The method of claim 11 , wherein the reference signals of the first radio access technology are demodulation reference signals, DMRS.

15. The method of claim 11 , wherein the reference signals of the second radio access technology are common or cell reference signals, CRS.

16. A wireless device configured to operate according to a first radio access technology, the wireless device adapted to:

receive an indication from a radio network node operating according to the first radio access technology and to a second radio access technology, the first and second radio access technologies using a same subcarrier spacing, the indication indicating that the first radio access technology and the second radio access technology are coexisting on a same carrier the indication being a parameter in an information element of a Radio Resource Control, RRC, message;

receive a downlink transmission from the radio network node, the downlink transmission including reference signals of the first radio access technology, the reference signals of the first radio access technology being located at a first symbol location within the downlink transmission when the reference signals of the first radio access technology are determined not to collide with reference signals of the second radio access technology, and the reference signals of the first radio access technology being located at a second symbol location within the downlink transmission when the reference signals of the first radio access technology are determined to collide with the reference signals of the second radio access technology, the second symbol location being either before the first symbol location or after the first symbol location.

17. The wireless device of claim 16 , wherein the parameter is a lte-CRS-ToMatchAround parameter.

18. The wireless device of claim 16 , wherein the second symbol location is either at least one symbol before the first symbol location or at least one symbol after the first symbol location.

19. The wireless device of claim 16 , wherein the reference signals of the first radio access technology are demodulation reference signals, DMRS.

20. The wireless device of claim 16 , wherein the reference signals of the second radio access technology are common or cell reference signals, CRS.