Methods and apparatuses for reliable multi-transmission systems

1. A method for enhancing transmission reliability, the method comprising:

receiving information indicating at least one of a constellation pattern or a plurality of indices associated with a plurality of transmit/receive points (TRPs);

determining, based on the information indicating at least one of the constellation pattern or the plurality of indices associated with the plurality of TRPs, a plurality of constellations for transmitting each of a plurality of repetitions of a data payload to a respective one of the plurality of TRPs, wherein the repetitions of the data payload comprise sets of coded bit sequences;

determining, for each repetition of the data payload, based on one of the sets of coded bit sequences and based on one of the determined plurality of constellations, a set of modulation symbols, wherein at least a first set of modulation symbols and a second set of modulation symbols are different;

allocating time and frequency resources for transmitting the determined sets of modulation symbols; and

transmitting, to the plurality of TRPs, the determined sets of modulation symbols using the allocated time and frequency resources.

2. The method of claim 1 , wherein the determined plurality of constellations for transmitting each of the repetitions of the data payload vary based on at least one of a repetition index or a TRP index.

3. The method of claim 1 , wherein the determined plurality of constellations are the same for each of the transmissions of the determined sets of modulation symbols.

4. The method of claim 1 , further comprising interleaving a set of coded bit sequences prior to determining a set of modulation symbols based on the interleaved set of coded bit sequences and based on one of the determined plurality of constellations.

5. The method of claim 4 , further comprising interleaving the set of modulation symbols after determining the set of modulation symbols based on the interleaved set of coded bit sequences and based on one of the determined plurality of constellations.

6. A method for use by a wireless transmit/receive unit (WTRU), the method comprising:

receiving information indicating at least one of a constellation pattern or a plurality of indices associated with a plurality of transmit/receive points (TRPs);

receiving, in downlink transmissions from each of the plurality of TRPs, via allocated time and frequency resources, respective sets of modulation symbols, wherein at least a first one of the sets of modulation symbols and a second one of the sets of modulation symbols are different;

determining, based on the information indicating at least one of the constellation pattern or the plurality of indices associated with the plurality of TRPs, a constellation for each of the sets of modulation symbols, wherein at least two of the determined constellations are different;

demodulating the sets of modulation symbols using the determined constellations to obtain respective sets of coded bit sequences, wherein each of the sets of coded bit sequences corresponds to a repetition of a data payload; and

decoding the coded bit sequences to obtain the data payload.

7. The method of claim 6 , wherein the constellation determined for each of the sets of modulation symbols is determined based on at least one of a repetition index or a TRP index.

8. The method of claim 6 , wherein the determined constellation is the same for each of the sets of modulation symbols received from a respective TRP.

9. The method of claim 6 , further comprising deinterleaving a set of modulation symbols prior to demodulating the set of modulation symbols.

10. The method of claim 9 , further comprising deinterleaving a set of coded bit sequences after demodulating a respective set of modulation symbols.

11. A wireless transmit/receive unit (WTRU) comprising:

a transceiver; and

a processor operatively connected to the transceiver, wherein the transceiver and the processer are configured to:

receive information indicating at least one of a constellation pattern or a plurality of indices associated with a plurality of transmit/receive points (TRPs);

receive, in downlink transmissions from each of the plurality of TRPs, via allocated time and frequency resources, respective sets of modulation symbols, wherein at least a first one of the sets of modulation symbols and a second one of the sets of modulation symbols are different;

determine, based on the information indicating at least one of the constellation pattern or the plurality of indices associated with the plurality of TRPs, a constellation for each of the sets of modulation symbols, wherein at least two of the determined constellations are different;

demodulate the sets of modulation symbols using the determined constellations to obtain respective sets of coded bit sequences, wherein each of the sets of coded bit sequences corresponds to a repetition of a data payload; and

decode the coded bit sequences to obtain the data payload.

12. The WTRU of claim 11 , wherein the constellation for each of the sets of modulation symbols is determined based on at least one of a repetition index or a TRP index.

13. The WTRU of claim 11 , wherein the determined constellation is the same for each of the sets of modulation symbols received from a respective TRP.

14. The WTRU of claim 11 , further configured to deinterleave a set of modulation symbols prior to demodulating the set of modulation symbols.

15. The WTRU of claim 14 , further configured to deinterleave a set of coded bit sequences after demodulating a respective set of modulation symbols.

16. The method of claim 1 , wherein the determined constellations are permutations of a baseline constellation.

17. The method of claim 6 , wherein the determined constellations are permutations of a baseline constellation.

18. The WTRU of claim 11 , wherein the determined constellations are permutations of a baseline constellation.