Overhead reduction and reliability enhancements for DL control signaling
Methods, user equipment (UE), and base stations for downlink control information (DCI) formats reception or transmission are provided. A method of operating a UE to transmit a physical uplink shared channel (PUSCH) includes receiving a configuration for a number of bits for a field that indicates a parameter in a first downlink control information (DCI) format; and receiving a physical downlink control channel (PDCCH) that provides either the first DCI format scheduling the PUSCH or a second DCI format scheduling the PUSCH. The second DCI format includes a field with a predetermined number of bits that indicates the parameter. A minimum number of bits for the field in the first DCI format is smaller than the predetermined number of bits for the field in the second DCI format. The method also includes transmitting the PUSCH.
1 . A method for receiving physical downlink control channels (PDCCHs), the method comprising:
receiving:
a first PDCCH candidate over first symbols and over a number of control channel elements (CCEs), wherein the first PDCCH candidate provides a first downlink control information (DCI) format, and
a second PDCCH candidate over second symbols and over the number of CCEs, wherein the second PDCCH candidate provides a second DCI format; and
based on identification that the first DCI format and the second DCI format are the same, counting:
the first PDCCH candidate and the second PDCCH candidate as three PDCCH candidates towards a maximum number of PDCCH candidates per slot, and
non-overlapping CCEs of the first PDCCH candidate and of the second PDCCH candidate towards a maximum number of non-overlapping CCEs for receptions of PDCCH candidates per slot.
2 . The method of claim 1 , wherein the first symbols and the second symbols are in a same slot and do not overlap.
3 . The method of claim 1 , further comprising:
descrambling the first PDCCH candidate using a first scrambling sequence, and
descrambling the second PDCCH candidate using a second scrambling sequence, wherein the second scrambling sequence is different than the first scrambling sequence.
4 . The method of claim 1 , wherein a number for a PDCCH candidate associated with the first PDCCH candidate is same as a number for a PDCCH candidate associated with the second PDCCH candidate.
5 . The method of claim 1 , further comprising:
receiving a physical downlink shared channel (PDSCH), wherein:
the first DCI format and the second DCI format are the same,
the PDSCH is scheduled by the first DCI format and by the second DCI format, and
the first DCI format and the second DCI format indicate symbols for the PDSCH relative to an end of the second PDCCH candidate, wherein the second PDCCH candidate ends later than the first PDCCH candidate.
6 . The method of claim 1 , wherein:
the first PDCCH candidate and the second PDCCH candidate are received in a same control resource set (CORESET), and
the first PDCCH candidate and the second PDCCH candidate are over same CCEs.
7 . The method of claim 1 , wherein a first demodulation reference signal (DM-RS) associated with the first PDCCH candidate and a second DM-RS associated with the second PDCCH candidate have a same precoding.
8 . A user equipment (UE), comprising:
a transceiver configured to receive:
a first PDCCH candidate over first symbols and over a number of control channel elements (CCEs), wherein the first PDCCH candidate provides a first downlink control information (DCI) format, and
a second PDCCH candidate over second symbols and over the number of CCEs, wherein the second PDCCH candidate provides a second DCI format; and
a processor operably coupled to the transceiver, the processor configured to count, based on identification that the first DCI format and the second DCI format are the same:
the first PDCCH candidate and the second PDCCH candidate as three PDCCH candidates towards a maximum number of PDCCH candidates per slot, and
non-overlapping CCEs of the first PDCCH candidate and of the second PDCCH candidate towards a maximum number of non-overlapping CCEs for receptions of PDCCH candidates per slot.
9 . The UE of claim 8 , wherein the first symbols and the second symbols are in a same slot and do not overlap.
10 . The UE of claim 8 , wherein the transceiver is further configured to:
descramble the first PDCCH candidate using a first scrambling sequence, and
descramble the second PDCCH candidate using a second scrambling sequence, wherein the second scrambling sequence is different than the first scrambling sequence.
11 . The UE of claim 8 , wherein a number for a PDCCH candidate associated with the first PDCCH candidate is same as a number for a PDCCH candidate associated with the second PDCCH candidate.
12 . The UE of claim 8 , wherein:
the transceiver is further configured to receive a physical downlink shared channel (PDSCH), wherein:
the first DCI format and the second DCI format are the same,
the PDSCH is scheduled by the first DCI format and by the second DCI format, and
the first DCI format and the second DCI format indicate symbols for the PDSCH relative to an end of the second PDCCH candidate, wherein the second PDCCH candidate ends later than the first PDCCH candidate.
13 . The UE of claim 8 , wherein:
the first PDCCH candidate and the second PDCCH candidate are received in a same control resource set (CORESET), and
the first PDCCH candidate and the second PDCCH candidate are over same CCEs.
14 . The UE of claim 8 , wherein a first demodulation reference signal (DM-RS) associated with the first PDCCH candidate and a second DM-RS associated with the second PDCCH candidate have a same precoding.
15 . A base station, comprising:
a transceiver configured to transmit:
a first physical downlink control channel (PDCCH) candidate over first symbols and over a number of control channel elements (CCEs), wherein the first PDCCH candidate provides a first downlink control information (DCI) format, and
a second PDCCH candidate over second symbols and over the number of CCEs, wherein the second PDCCH candidate provides a second DCI format; and
a processor operably coupled to the transceiver, the processor configured to count, based on identification that the first DCI format and the second DCI format are the same:
the first PDCCH candidate and the second PDCCH candidate as three PDCCH candidates towards a maximum number of PDCCH candidates per slot, and
non-overlapping CCEs of the first PDCCH candidate and of the second PDCCH candidate towards a maximum number of non-overlapping CCEs for receptions of PDCCH candidates per slot.
16 . The base station of claim 15 , wherein the first symbols and the second symbols are in a same slot and do not overlap.
17 . The base station of claim 15 , wherein the transceiver is further configured to:
scramble the first PDCCH candidate using a first scrambling sequence, and
scramble the second PDCCH candidate using a second scrambling sequence, wherein the second scrambling sequence is different than the first scrambling sequence.
18 . The base station of claim 15 , wherein a number for a PDCCH candidate associated with the first PDCCH candidate is same as a number for a PDCCH candidate associated with the second PDCCH candidate.
19 . The base station of claim 15 , wherein:
the transceiver is further configured to transmit a physical downlink shared channel (PDSCH), wherein:
the first DCI format and the second DCI format are the same,
the PDSCH is scheduled by the first DCI format and by the second DCI format, and
the first DCI format and the second DCI format indicate symbols for the PDSCH relative to an end of the second PDCCH candidate, wherein the second PDCCH candidate ends later than the first PDCCH candidate.
20 . The base station of claim 15 , wherein:
the first PDCCH candidate and the second PDCCH candidate are transmitted in a same control resource set (CORESET), and
the first PDCCH candidate and the second PDCCH candidate are over same CCEs.