Rate matching and semi persistent scheduling configuration in wireless communications
Methods, systems, and devices for wireless communications are described for identifying a modulation and coding scheme (MCS) independently of a channel quality indicator (CQI) table that is configured at a user equipment (UE). A rate matching parameter may be determined based on one or more of the MCS or CQI table, which may be used for dimensioning a soft buffer that is used to store received transmissions for decoding. The MCS field may be a six-bit field and may indicate an MCS that exceeds a highest MCS associated with the CQI table. The base station may activate a semi-persistent scheduling (SPS) configuration at the UE through an activation command, and the UE may verify that SPS is activated based on information in a number of different fields of control information which may include the MCS field.
1. A method for wireless communication at a user equipment (UE), comprising:
transmitting capability information to a base station that indicates that the UE has capability for a 1024 quadrature amplitude modulation (QAM) modulation order;
receiving, from the base station, radio resource control (RRC) signaling that includes signaled modulation order information;
receiving, from the base station, control information for a downlink transmission, the control information including a first index value for a first entry in a modulation and coding scheme (MCS) table, wherein the first entry in the MCS table indicates a first modulation order that is different than a second modulation order indicated by the signaled modulation order information, and wherein the first modulation order is 1024 QAM based on the transmitted capability information; and
determining a rate matching parameter for the downlink transmission based at least in part on the first modulation order.
2. The method of claim 1 , further comprising:
determining a transport block size for the downlink transmission based at least in part on the first modulation order and a scaling value applied to a number of allocated resource elements.
3. The method of claim 1 , further comprising:
receiving an indication of a scaling parameter associated with the first index value.
4. The method of claim 1 , wherein the rate matching parameter is based at least in part on a highest supported modulation order supported by the UE for a radio frequency band or band combination used for the downlink transmission.
5. The method of claim 1 , further comprising:
determining a first transport block size for the downlink transmission based at least in part on the first modulation order.
6. The method of claim 1 , wherein the control information comprises a downlink control information (DCI) format 1 / 1 A.
7. The method of claim 1 , wherein one or more fields of the control information is scrambled by a cell radio network temporary identifier (C-RNTI).
8. The method of claim 1 , wherein the first index value is a six-bit index value that identifies the first entry from 64 available entries of the MCS table.
9. The method of claim 1 , wherein the determining the rate matching parameter comprises:
identifying a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the UE and the base station;
determining that the first modulation order exceeds a maximum modulation order of the one or more modulation orders of the CQI table; and
determining the rate matching parameter based on a highest entry in the MCS table that has a modulation order that is supported by the UE.
10. The method of claim 1 , further comprising:
identifying a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the UE and the base station; and
transmitting, to the base station, a capability indication that indicates the UE is capable of operating at a modulation order that exceeds a maximum modulation order 6 indicated by the CQI table.
11. The method of claim 10 , further comprising:
receiving, responsive to the capability indication, a modulation order indication that indicates that the base station will transmit one or more downlink transmissions having the modulation order that exceeds the maximum modulation order indicated by the CQI table; and
processing the control information based on the modulation order indication.
12. The method of claim 11 , further comprising:
selecting an operating power for one or more receive components of the UE based at least in part on the modulation order indication.
13. A method for wireless communication at a base station, comprising:
receiving capability information from a user equipment (UE) that indicates that the UE has capability for a 1024 quadrature amplitude modulation (QAM) modulation order;
transmitting, to the UE, radio resource control (RRC) signaling that includes signaled modulation order information;
transmitting, to the UE, control information for a downlink transmission, the control information including a first index value for a first entry in a modulation and coding scheme (MCS) table, wherein the first entry in the MCS table indicates a first modulation order that is different than a second modulation order indicated by the signaled modulation order information, and wherein the first modulation order is 1024 QAM based on the received capability information; and
transmitting the downlink transmission to the UE using the first modulation order.
14. The method of claim 13 , wherein the first index value is a six-bit index value that identifies the first entry from 64 available entries of the MCS table.
15. The method of claim 13 , wherein the first modulation order is selected to be at or below a maximum modulation order of a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the base station and the UE.
16. The method of claim 13 , further comprising:
determining a highest modulation order supported by the UE for a radio frequency band or band combination to be used for the downlink transmission;
selecting the first modulation order as the highest modulation order, wherein the first modulation order corresponds to or exceeds a maximum modulation order of a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the base station and the UE; and
transmitting the downlink transmission using the highest modulation order supported by the UE.
17. The method of claim 13 , further comprising:
transmitting an indication of a scaling parameter associated with the first index value, the scaling parameter indicating a scaling value that is applied to a number of allocated resource elements for determining a transport block size for the downlink transmission.
18. The method of claim 13 , further comprising:
determining a first transport block size for the downlink transmission that is less than or equal to a maximum transport block size that is identified based at least in part on a maximum modulation order of one or more modulation orders of a channel quality indication (CQI) table that provides one or more parameters associated with the one or more modulation orders for transmissions between the base station and the UE, and wherein the downlink transmission uses the first transport block size.
19. The method of claim 13 , wherein the control information is first control information and the downlink transmission is a first downlink transmission, and wherein the method further comprises:
transmitting, to the UE, second control information for a second downlink transmission, the second control information including a second index value for a second entry in the MCS table; and
transmitting the second downlink transmission using the first modulation order.
20. The method of claim 13 , further comprising:
receiving, from the UE, a capability indication that indicates the UE is capable of operating at a modulation order that exceeds a maximum modulation order indicated by a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the base station and the UE.
21. The method of claim 20 , further comprising:
transmitting, responsive to the capability indication, a modulation order indication that indicates that the base station will transmit one or more downlink transmissions having the modulation order that exceeds the maximum modulation order indicated by CQI table.
22. An apparatus for wireless communication at a user equipment (UE), comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
transmit capability information to a base station that indicates that the UE has capability for a 1024 quadrature amplitude modulation (QAM) modulation order;
receive, from the base station, radio resource control (RRC) signaling that includes signaled modulation order information
receive, from the base station, control information for a downlink transmission, the control information including a first index value for a first entry in a modulation and coding scheme (MCS) table, wherein the first entry in the MCS table indicates a first modulation order that is different than a second modulation order indicated by the signaled modulation order information, and wherein the first modulation order is 1024 QAM based on the transmitted capability information; and
determine a rate matching parameter for the downlink transmission based at least in part on the first modulation order.
23. The apparatus of claim 22 , wherein the instructions are further executable by the processor to cause to the apparatus to:
determine a transport block size for the downlink transmission based at least in part on the first modulation order and a scaling value applied to a number of allocated resource elements.
24. The apparatus of claim 22 , wherein the instructions are further executable by the processor to cause to the apparatus to:
determine a first transport block size for the downlink transmission based at least in part on the first modulation order.
25. The apparatus of claim 22 , further comprising:
at least one antenna for receiving the control information for the downlink transmission, and wherein the first index value is a six-bit index value that identifies the first entry from 64 available entries of the MCS table.
26. An apparatus for wireless communication at a base station, comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
receive capability information from a user equipment (UE) that indicates that the UE has capability for a 1024 quadrature amplitude modulation (QAM) modulation order;
transmit, to the UE, radio resource control (RRC) signaling that includes signaled modulation order information;
transmit, to the UE, control information for a downlink transmission, the control information including a first index value for a first entry in a modulation and coding scheme (MCS) table, wherein the first entry in the MCS table indicates a first modulation order that is different than a second modulation order indicated by the signaled modulation order information, and wherein the first modulation order is 1024 QAM based on the received capability information; and
transmit the downlink transmission to the UE using the first modulation order.
27. The apparatus of claim 26 , further comprising:
at least one antenna for transmitting the control information for the downlink transmission, and wherein the first index value is a six-bit index value that identifies the first entry from 64 available entries of the MCS table.
28. The apparatus of claim 26 , wherein the instructions are further executable by the processor to cause to the apparatus to:
transmit an indication of a scaling parameter associated with the first index value, the scaling parameter indicating a scaling value that is applied to a number of allocated resource elements for determining a transport block size for the downlink transmission.
29. The apparatus of claim 26 , wherein the instructions are further executable by the processor to cause to the apparatus to:
receive, from the UE, a capability indication that indicates the UE is capable of operating at a modulation order that exceeds a maximum modulation order indicated by a channel quality indication (CQI) table that provides one or more parameters associated with one or more modulation orders for transmissions between the base station and the UE.
30. The apparatus of claim 29 , the instructions are further executable by the processor to cause to the apparatus to:
transmit, responsive to the capability indication, a modulation order indication that indicates that the base station will transmit one or more downlink transmissions having the modulation order that exceeds the maximum modulation order indicated by the CQI table.