Determining phase tracking reference signals in multiple transmission points
A method for a UE in a multiple transmission points communication system, mTRP, scheme, is provided. The method includes receiving downlink control information, DCI, indicating at least two transmission points scheme for a scheduled data transmission on physical resource blocks, PRBs. The PRBs includes at least a first subsets of PRBs, associated with a first transmission point, and a second subset of PRBs, associated with a second transmission point. The method further includes determining a first PT-RS frequency density for the first set of PRBs based on the number of PRBs in the first set of PRBs and a second PT-RS frequency density based on the number of PRBs in the second set of PRBs. A UE, methods for a base station and a base station are also provided.
1. A method for a UE in a multiple transmission points communication system, mTRP, the method comprising:
receiving downlink control information, DCI, indicating a first Transmission Configuration Indicator, TCI, state and a second TCI state, and at least one demodulation reference signal, DMRS, port in one Code Division Multiplexing, CDM, group for a physical downlink shared channel, PDSCH, transmission on physical resource blocks, PRBs, wherein the PRBs comprise at least a first subset of PRBs, associated with the first TCI state, and a second subset of PRBs, associated with the second TCI state; and
determining a first Phase Tracking Reference Signal, PT-RS, frequency density for the first subset of PRBs based on a number of PRBs in the first subset of PRBs and a second PT-RS frequency density for the second subset of PRBs based on a number of PRBs in the second subset of PRBs.
2. A method according to claim 1 , wherein a TCI state corresponds to a transmission point.
3. A method according to claim 1 , further comprising transmitting a single PT-RS port associated with a lowest index DM-RS port.
4. A method according to claim 1 , wherein the first TCI state is associated with a first transmission point in the multiple transmission points communication system and wherein the second TCI state is associated with a second transmission point in the multiple transmission points communication system.
5. A method according to claim 1 , wherein the PT-RS to resource element mapping is associated to allocated PRBs for each TCI state.
6. A method according to claim 1 , further comprising receiving a higher layer configuration of a mTRP scheme, wherein the mTRP scheme is one of a FDM Scheme 2a, wherein a single PDSCH transmission for a transport block, TB, is scheduled across the first subset of PRBs and the second subset of PRBs, or a FDM Scheme 2b, wherein a first PDSCH transmission for a TB is scheduled in the first subset of PRBs and a second PDSCH transmission for the same TB is scheduled in the second subset of PRBs.
7. A UE operable in a multiple transmission points communication system, mTRP, the UE comprising a transceiver and processing circuitry configured to:
receive downlink control information, DCI, indicating a first Transmission Configuration Indicator, TCI, state and a second TCI state, and at least one demodulation reference signal, DMRS, port in one Code Division Multiplexing, CDM, group for a Physical Downlink Shared Channel, PDSCH, transmission on physical resource blocks, PRBs, wherein the PRBs comprise at least a first subset of PRBs, associated with the first TCI state, and a second subset of PRBs, associated with the second TCI state; and
determine a first Phase Tracking Reference Signal, PT-RS, frequency density for the first subset of PRBs based on a number of PRBs in the first subset of PRBs and a second PT-RS frequency density for the second subset of PRBs based on a number of PRBs in the second subset of PRBs.
8. A UE according to claim 7 , wherein a TCI state corresponds to a transmission point.
9. A UE according to claim 7 , wherein the transceiver and processing circuitry are further configured to transmit a single PT-RS port associated with a lowest index DM-RS port.
10. A UE according to claim 7 , wherein the first TCI state is associated with a first transmission point in the multiple transmission points communication system and wherein the second TCI state is associated with a second transmission point the multiple transmission points communication system.
11. A UE according to claim 7 , wherein the PT-RS to resource element mapping is associated to allocated PRBs for each TCI state.
12. A UE according to claim 7 , wherein the UE is further configured to receive a higher layer configuration of a mTRP scheme, wherein the mTRP scheme is one of a FDM Scheme 2a, wherein a single PDSCH transmission for a transport block, TB, is scheduled across the first subset of PRBs and the second subset of PRBs, or a FDM Scheme 2b, wherein a first PDSCH transmission for a TB is scheduled in the first subset of PRBs and a second PDSCH transmission for the same TB is scheduled in the second subset of PRBs.
13. A method for a base station in a multiple transmission points communication system, mTRP, scheme, the method comprising:
transmitting downlink control information, DCI, indicating a first Transmission Configuration Indicator, TCI, state and a second TCI state, and least one demodulation reference signal, DMRS, port in one Code Division Multiplexing, CDM, group for a Physical Downlink Shared Channel, PDSCH, transmission on physical resource blocks, PRBs, wherein the PRBs comprise at least a first subset of PRBs, associated with the first TCI state, and a second subset of PRBs, associated with the second TCI state; and
wherein a first Phase Tracking Reference Signal, PT-RS, frequency density for the first subset of PRBs is obtainable based on a number of PRBs in the first subset of PRBs and a second PT-RS frequency density for the second subset of PRBs is obtainable based on a number of PRBs in the second subset of PRBs.
14. A method according to claim 13 , wherein a TCI state corresponds to a transmission point.
15. A method according to claim 13 , further comprising transmitting a single PT-RS port associated with a lowest index DM-RS port.
16. A method according to claim 13 , wherein the first TCI state is associated with a first transmission point in the multiple transmission points communication system and wherein the second TCI state is associated with a second transmission point in the multiple transmission points communication system.
17. A method according to claim 13 , wherein the PT-RS to resource element mapping is associated to allocated PRBs for each TCI state.
18. A method according to claim 13 , further comprising transmitting a higher layer configuration of a mTRP scheme, wherein the mTRP scheme is one of a FDM Scheme 2a, wherein a single PDSCH transmission for a transport block, TB, is scheduled across the first subset of PRBS and the second subset of PRBs, or a FDM Scheme 2b, wherein a first PDSCH transmission for a TB is scheduled in the first subset of PRBs and a second PDSCH transmission for the same TB is scheduled in the second subset of PRBs.
19. A base station operable in a multiple transmission points communication system, mTRP, scheme, the base station comprising a transceiver and processing circuitry and configured to:
transmit downlink control information, DCI, indicating a first Transmission Configuration Indicator, TCI, state and a second TCI state, and at least one demodulation reference signal, DMRS, port in one Code Division Multiplexing, CDM, group for a Physical Downlink Shared Channel, PDSCH, transmission on physical resource blocks, PRBs, wherein the PRBs comprise at least a first subset of PRBs, associated with the first TCI state, and a second subset of PRBs, associated with the second TCI state; and
wherein a first Phase Tracking Reference Signal, PT-RS, frequency density for the first subset of PRBs is obtainable based on a number of PRBs in the first subset of PRBs and a second PT-RS frequency density for the second subset of PRBs is obtainable based on a number of PRBs in the second subset of PRBs.
20. A base station according to claim 19 , wherein a TCI state corresponds to a transmission point.
21. A base station according to claim 19 , wherein the base station is further configured to transmit a single PT-RS port associated with a lowest index DM-RS port.
22. A base station according to claim 19 , wherein the first TCI state is associated with a first transmission point in the multiple transmission points communication system and wherein the second TCI state is associated with a second transmission point in the multiple transmission points communication system.
23. A base station according to claim 19 , wherein the PT-RS to resource element mapping is associated to allocated PRBs for each TCI state.
24. A base station according to claim 19 , wherein the base station is further configured to transmit a higher layer configuration of a mTRP scheme, wherein the mTRP scheme is one of a FDM Scheme 2a, wherein a single PDSCH transmission for a transport block, TB, is scheduled across the first subset of PRBS and the second subset of PRBs, or a FDM Scheme 2b, wherein a first PDSCH transmission for a TB is scheduled in the first subset of PRBs and a second PDSCH transmission for the same TB is scheduled in the second subset of PRBs.