Repetition for ultra-reliable low-latency communications
Embodiments include methods, performed by a user equipment (UE), for communicating via a plurality of nodes in a wireless network. Such methods include receiving a plurality of Transmission Configuration Indicator (TCI) states, and receiving, via a single physical control channel, scheduling information for a plurality of physical data channels carrying a respective plurality of repetitions of a data block. The physical data channels can be respective layers of a PDSCH, or each physical data channel can be a subset of all layers of a PDSCH. Such methods include assigning one or more of the TCI states to the plurality of repetitions, and receiving the plurality of repetitions via the plurality of physical data channels based on the scheduling information and the assigned TCI states. Embodiments also include complementary methods performed by a wireless network, as well as UEs and wireless networks configured to perform such methods.
1. A method, performed by a user equipment (UE), for communicating via a plurality of nodes in a wireless network, the method comprising:
receiving a plurality of Transmission Configuration Indicator (TCI) states;
receiving, via a single physical control channel, scheduling information for a plurality of physical data channels carrying a respective plurality of repetitions of a data block, wherein:
the scheduling information includes an indicator of a mapping between one or more of the TCI states and the plurality of repetitions;
the indicator is included in a field having a plurality of codepoints, the plurality of TCI states being less than the plurality of codepoints;
a first subset of the codepoints are associated with individual TCI states; and
a second subset of the codepoints are associated with combinations of individual TCI states;
based on the indicated mapping, assigning one or more of the TCI states to the plurality of repetitions; and
receiving the plurality of repetitions via the plurality of physical data channels based on the scheduling information and the assigned TCI states.
2. The method of claim 1 , wherein:
the plurality of TCI states is less than the plurality of repetitions; and
the plurality of TCI states are assigned to the repetitions in a predefined order.
3. The method of claim 1 , wherein:
the scheduling information also includes an indicator of resources for receiving one or more of the repetitions; and
the indicated resources are in at least one of the following dimensions: time, frequency, and spatial layer.
4. The method of claim 3 , wherein the resources for at least two of the repetitions are in the same set of symbols in a slot.
5. The method of claim 3 , wherein:
the scheduling information includes an indicator of first resources for receiving a first one of the repetitions; and
the method further comprises receiving one or more offsets to be applied to the first resources to determine further resources for receiving the remaining ones of the repetitions.
6. The method of claim 5 , wherein the further resources are located in one of the following with respect to the first resources: one or more subsequent slots, or one or more subsequent symbols within the same slot.
7. The method of claim 3 , wherein:
the indicated resources for at least two of the repetitions overlap completely in frequency; and
the scheduling information also includes at least one of the following for each of the completely overlapping repetitions:
a unique set of demodulation reference signal (DM-RS) ports;
DMRS ports from a unique code-division multiplexing (CDM) group; and
a unique data scrambling seed.
8. The method of claim 1 , wherein the scheduling information also includes an indicator of a mapping between the plurality of repetitions and a plurality of redundancy versions (RV) of the data block.
9. The method of claim 1 , wherein:
each TCI state includes one or more source reference signal (RS) pairs;
each source RS pair has a corresponding pair of quasi-colocation (QCL) relations with antenna ports, for demodulation reference signals (DM-RS) that are mapped to a particular physical data channel; and
the method further comprises, for each of the plurality of TCI states, determining channel parameters based on the source RS pairs included in the particular TCI state.
10. The method of claim 9 , wherein receiving the plurality of repetitions via the plurality of physical data channels further comprises, for each of the physical data channels:
based on the channel parameters, receiving the DM-RS mapped to the physical data channel;
determining further channel parameters based on the received DM-RS; and
receiving the physical data channel based on the further channel parameters.
11. The method of claim 1 , wherein the plurality of TCI states are associated with one of the following:
a respective plurality of nodes in the wireless network; or
a respective plurality of beams associated with one or more nodes in the wireless network.
12. The method of claim 1 , wherein one of the following applies:
the plurality of physical data channels are respective layers of a physical downlink shared channel (PDSCH); or
each physical data channel is a subset of all layers of a PDSCH.
13. A user equipment (UE) configured to communicate via a plurality of nodes in a wireless network, the UE comprising:
radio transceiver circuitry configured to communicate with the plurality of nodes; and
processing circuitry operatively coupled to the radio transceiver circuitry, whereby the processing circuitry and the radio transceiver circuitry are configured to perform operations corresponding to the method of claim 1 .
14. A method, performed by one or more nodes in a wireless network, for communicating via a plurality of physical data channels with a single user equipment (UE), the method comprising:
transmitting, to the UE, a plurality of Transmission Configuration Indicator (TCI) states;
assigning one or more of the TCI states to a plurality of repetitions, of a data block, to be carried by a respective plurality of physical data channels, wherein the assigning is according to a mapping between one or more of the TCI states and the plurality of repetitions;
transmitting, to the UE via a single physical control channel, scheduling information for the plurality of physical data channels carrying the respective plurality of repetitions, wherein:
the scheduling information includes an indicator of the mapping;
the indicator is included in a field having a plurality of codepoints, the plurality of TCI states being less than the plurality of codepoints;
a first subset of the codepoints are associated with individual TCI states; and
a second subset of the codepoints are associated with combinations of individual TCI states; and
transmitting the plurality of repetitions via the plurality of physical data channels based on the scheduling information and the assigned TCI states.
15. The method of claim 14 , wherein:
the plurality of TCI states is less than the plurality of repetitions; and
the plurality of TCI states are assigned to the repetitions in a predefined order.
16. The method of claim 14 , wherein:
the scheduling information also includes an indicator of resources for transmitting or receiving one or more of the repetitions; and
the indicated resources are in at least one of the following dimensions: time, frequency, and spatial layer.
17. The method of claim 16 , wherein the resources for at least two of the repetitions are in the same set of symbols in a slot.
18. The method of claim 16 , wherein:
the scheduling information includes an indicator of first resources for receiving a first one of the repetitions; and
the method further comprises transmitting one or more offsets to be applied to the first resources to determine further resources for receiving the remaining ones of the repetitions.
19. The method of claim 18 , wherein the further resources are located in one of the following with respect to the first resources: one or more subsequent slots, or one or more subsequent symbols within the same slot.
20. The method of claim 16 , wherein:
the indicated resources for at least two of the repetitions overlap completely in frequency; and
the scheduling information also includes at least one of the following for each of the completely overlapping repetitions:
a unique set of demodulation reference signal (DM-RS) ports;
DMRS ports from a unique code-division multiplexing (CDM) group; and
a unique data scrambling seed.
21. The method of claim 14 , wherein the scheduling information also includes an indicator of a mapping between the plurality of repetitions and a plurality of redundancy versions (RV) of the data block.
22. The method of claim 14 , wherein:
each TCI state includes one or more source reference signal, RS, pairs;
each source RS pair has a corresponding pair of quasi-colocation (QCL) relations with antenna ports, for demodulation reference signals (DM-RS) that are mapped to a particular physical data channel;
the method further comprises, for each of the plurality of TCI states, transmitting the source RS pairs included in the particular TCI state; and
transmitting the plurality of repetitions via the plurality of physical data channels further comprises transmitting the respective DM-RS in association with the physical data channels to which they are mapped.
23. The method of claim 14 , wherein the plurality of TCI states are associated with one of the following:
a respective plurality of nodes in the wireless network; or
a respective plurality of beams associated with one or more nodes in the wireless network.
24. The method of claim 14 , wherein one of the following applies:
the plurality of physical data channels are respective layers of a physical downlink shared channel (PDSCH); or
each physical data channel is a subset of all layers of a PDSCH.
25. A wireless network comprising one or more nodes, the wireless network being configured to communicate via a plurality of physical shared channels with a single user equipment (UE), the one or more nodes comprising:
radio network interface circuitry configured to communicate with the UE; and
processing circuitry operatively coupled to the radio network interface circuitry, whereby the processing circuitry and the radio network interface circuitry are configured to perform operations corresponding to the method of claim 14 .