Methods for flexible reference signal transmission with single carrier frequency domain multiple access (SC-FDMA) and OFDMA
A method for transmitting a discrete fourier transform (DFT) DFT-S-OFDM signal including frequency domain reference symbols is disclosed. The method comprises: determining to null a plurality of data symbols prior to DFT-spreading; performing DFT-spreading including the determined null data symbols; puncturing an interleaved output of the DFT-spreading; inserting reference symbols in a frequency domain of the punctured and interleaved DFT-S-OFDM signal; and transmitting the DFT-S-OFDM signal with inserted reference symbols to a receiver. The transmitted DFT-S-OFDM signal enables the receiver to apply zeros corresponding to the reference symbols to an interleaved input of DFT-despreading, and cancel interference due to the puncturing by using all outputs of the DFT-despreading.
1. A method comprising:
receiving, by a wireless transmit/receive unit (WTRU), dynamic scheduling information from a base station, the dynamic scheduling information indicates discrete Fourier transform spread—orthogonal frequency division multiplex (DFTS-OFDM) symbol times and a number of DFTS-OFDM symbols to use for reference signal symbols for a first physical uplink shared channel (PUSCH) transmission;
transmitting, by the WTRU, the first PUSCH transmission using DFTS-OFDM having reference signals at the indicated DFTS-OFDM symbol times and the indicated number of DFTS-OFDM symbols to use for reference signal symbols;
receiving, by the WTRU, second dynamic scheduling information; and
transmitting, by the WTRU, a second PUSCH transmission using DFTS-OFDM having reference signal symbols at symbol times and a number of DFTS-OFDM symbols indicated by the second dynamic scheduling information, wherein symbol times or numbers of symbols to use for reference signals differ between the dynamic scheduling information and the second dynamic scheduling information.
2. The method of claim 1 wherein the base station is a gNodeB and the WTRU is a new radio (NR) user equipment (UE).
3. The method of claim 1 wherein in response to receiving, by the WTRU, second dynamic scheduling information the second PUSCH transmission includes nulled subcarriers in a symbol used to transmit a reference signal.
4. The method of claim 1 wherein symbol times or numbers of symbols to use for reference signals differ between the dynamic scheduling information and the second dynamic scheduling information based on channel conditions.
5. A wireless transmit receive unit (WTRU) comprising:
a receiver configured to receive dynamic scheduling information from a base station, the dynamic scheduling information indicates discrete Fourier transform spread—orthogonal frequency division multiplex (DFTS-OFDM) symbol times and a number of DFTS-OFDM symbols to use for reference signal symbols for a first physical uplink shared channel (PUSCH) transmission
a transmitter configured to transmit the first PUSCH transmission using DFTS-OFDM having reference signals at the indicated DFTS- OFDM symbol times and the indicated number of DFTS-OFDM symbols to use for reference signal symbols;
the receiver is further configured to receive a second dynamic scheduling information, and
the transmitter is further configured to transmit a second PUSCH transmission using DFTS-OFDM having reference symbols at symbol times and a number of DFTS-OFDM symbols indicated by the second dynamic scheduling information, wherein symbol times or numbers of symbols to use for reference signals differ between the dynamic scheduling information and the second dynamic scheduling information.
6. The WTRU of claim 5 , wherein the base station is a gNodeB and the WTRY is a new radio (NR) user equipment.
7. The WTRU of claim 5 , wherein in response to the second dynamic scheduling information, the transmitter is configured to transmit the second PUSCH transmission having nulled subcarriers in a symbol used to transmit a reference signal.
8. The WTRU of claim 5 , wherein symbol times or numbers of symbols to use for reference signals differ between the dynamic scheduling information and the second dynamic scheduling information based on channel conditions.
9. A wireless transmit receive unit (WTRU) comprising:
a receiver configured to receive dynamic scheduling information from a base station, the dynamic scheduling information indicates discrete Fourier transform spread—orthogonal frequency division multiplex (DFTS-OFDM) symbol times and a number of DFTS-OFDM symbols to use for reference signal symbols for a physical uplink shared channel (PUSCH) transmission, the receiver is further configured to receive a second dynamic scheduling information; and
a transmitter configured to transmit a first signal on a the PUSCH using DFTS-OFDM, the first signal having reference signals at the indicated symbol times and number of DFTS-OFDM symbols, and the transmitter is further configured to transmit, a second signal on the PUSCH using DFTS-OFDM having reference symbols at symbol times and number of DFTS-OFDM symbols indicated by the second dynamic scheduling information, wherein symbol times or numbers of symbols to use for reference signals differ between the dynamic scheduling information and the second dynamic scheduling information.
10. The WTRU of claim 9 , wherein the base station is a gNodeB and the WTRU is a new radio (NR) user equipment (UE).
11. The WTRU of claim 9 , wherein numbers of DFTS-OFDM symbols to use for reference signal symbols increases as the channel conditions become poorer.