Dynamic demodulation signal resource allocation
Systems, apparatus and methods are described for dynamic demodulation signal resource allocation. PDSCH/PUSCH DMRS enhancement is provided. A dynamic indication of reference signal functionality may be provided in a slot for an additional DM-RS. A configured CSI-RS/SRS may be dynamically indicated to use as an additional DM-RS in a slot. Frequency shift/hopping of DM-RS as a function of OFDM symbol and/or the order of OFDM symbol containing DM-RS may increase frequency density within a slot. DM-RS antenna port aggregation may increase DM-RS frequency density. One or more DM-RS antenna ports may be used to demodulate the same layer. PDCCH DMRS enhancement is provided. Frequency shift/hopping of PDCCH DMRS may be provided as a function of a REG index within an REG bundle, OFDM symbol index, etc. Use of multiple types of REG (e.g., low and high DM-RS) and REG type may be determined based on subcarrier spacing, operating frequency band, etc.
1. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising:
receiving information indicating a control resource set (CORESET) configuration of a CORESET, the CORESET configuration including an indication of a symbol duration and/or an indication of physical downlink control channel (PDCCH) demodulation reference signal (DM-RS) frequency hopping or density changing;
determining a plurality of DM-RS positions in one or more resource element groups (REGs) of the CORESET based on (1) the indication of the symbol duration and/or the indication of the PDCCH DM-RS frequency hopping or density changing, and (2) respective indices of the one or more REGs;
receiving a PDCCH transmission in a search space associated with the CORESET with one or more PDCCH DM-RSs in the plurality of DM-RS positions in the one or more REGs;
decoding the received PDCCH transmission using the one or more PDCCH DM-RSS in the plurality of DM-RS positions; and
receiving a physical downlink shared channel (PDSCH) transmission or sending a physical uplink shared channel (PUSCH) transmission based on one or more downlink control information (DCI) fields of the decoded PDCCH transmission.
2. The method of claim 1 , wherein the determining of the plurality of DM-RS positions in the one or more REGs of the CORESET is further based on any of (3) a DCI format and/or (4) an aggregation level.
3. The method of claim 1 , wherein the plurality of DM-RS positions are in at least a first REG having a lowest index among the one or more REGs of the CORESET.
4. The method of claim 1 , wherein the determining of the plurality of DM-RS positions in the one or more REGs of the CORESET is based on the indication of PDCCH DM-RS frequency hopping and the respective indices of each of the one or more REGs, and the plurality of DM-RS positions have different locations in frequency in each of the one or more REGs.
5. The method of claim 4 , wherein the plurality of DM-RS positions in adjacent REGs of the one or more REGs are in consecutive resource elements in frequency.
6. The method of claim 1 , wherein the plurality of DM-RS positions in adjacent REGs of the one or more REGs are in consecutive resource elements in frequency.
7. The method of claim 1 , wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different ones of the one or more REGs of the CORESET.
8. The method of claim 1 , wherein the determining of the plurality of DM-RS positions in the one or more REGs of the CORESET are based on the indication of PDCCH DM-RS density changing and the respective indices of each of the one or more REGs, and the plurality of DM-RS positions are in only one REG of the one or more REGs.
9. The method of claim 8 , wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different ones of the one or more REGs of the CORESET.
10. The WTRU of claim 8 , wherein the processor is configured to determine the plurality of DM-RS positions in the one or more REGs of the CORESET is based on the indication of PDCCH DM-RS frequency hopping and the respective indices of each of the one or more REGs, and the plurality of DM-RS positions have different locations in frequency in each of the one or more REGs.
11. A wireless transmit/receive unit (WTRU), comprising:
a processor and a transceiver which are configured to:
receive information indicating a control resource set (CORESET) configuration of a CORESET, the CORESET configuration including an indication of a symbol duration and/or an indication of physical downlink control channel (PDCCH) demodulation reference signal (DM-RS) frequency hopping or density changing,
determine a plurality of DM-RS positions in one or more resource element groups (REGs) of the CORESET based on (1) the indication of the symbol duration and/or the indication of the PDCCH DMRS frequency hopping or density changing, and (2) respective indices of the one or more REGs,
receive a PDCCH transmission in a search space associated with the CORESET with one or more PDCCH DM-RSs in the plurality of DM-RS positions in the one or more REGs,
decode the received PDCCH transmission using the one or more PDCCH DM-RSs in the plurality of DM-RS positions, and
receive a physical downlink shared channel (PDSCH) transmission or send a physical uplink shared channel (PUSCH) transmission based on one or more downlink control information (DCI) fields of the decoded PDCCH transmission.
12. The WTRU of claim 11 , wherein the processor is configured to determine the plurality of DM-RS positions in the one or more REGs of the CORESET further based on any of (3) a DCI format and/or (4) an aggregation level.
13. The WTRU of claim 11 , wherein the plurality of DM-RS positions are in at least a first REG having a lowest index among the one or more REGs of the CORESET.
14. The WTRU of claim 11 , wherein the plurality of DM-RS positions in adjacent REGs of the one or more REGs are in consecutive resource elements in frequency.
15. The WTRU of claim 11 , wherein the plurality of DM-RS positions in adjacent REGs of the one or more REGs are in consecutive resource elements in frequency.
16. The WTRU of claim 11 , wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different ones of the one or more REGs of the CORESET.
17. The WTRU of claim 11 , wherein the determining of the plurality of DM-RS positions in the one or more REGs of the CORESET are based on the indication of PDCCH DM-RS density changing and based on the respective REG index of each of the one or more REGs, and the plurality of DM-RS positions are in only one REG of the one or more REGs.
18. The WTRU of claim 17 , wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different ones of the one or more REGs of the CORESET.
19. The WTRU of claim 11 , wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are located in less than all of the REGs of the CORESET.