Aggregation indication for uplink transmission during random access channel procedures
Systems for providing coverage enhancement for Msg 3 PUSCH and PUCCH carrying the HARQ-ACK for Msg4 of PRACH initial access are described. The gNB provides a 2-bit aggregation factor for transmission of the Msg3 PUSCH in an RAR UL grant field. The PUSCH frequency resource allocation field is limited to 12 bits so that the RAR has an overall number of bits that is the same as an RAR that does not contain the aggregation factor. A default PUSCH TDRA table includes a field to indicate a repetition level for Msg3 PUSCH transmission. For retransmissions, fields in DCI format 0_0 are repurposed to indicate an aggregation factor. Inter-slot frequency hopping may be configured by higher layers. Different PRACH resources are used to indicate UE coverage status.
1. An apparatus for user equipment (UE) configured for operation in a fifth-generation (5G) new-radio (5G-NR) system, the apparatus comprising: processing circuitry; and memory, the processing circuitry configured to perform a random access procedure comprising:
configuring the UE for transmission of a random access preamble (Msg1) in a physical random access channel (PRACH);
configuring the UE for reception of a random access response (RAR) message (Msg2) in response to transmission of the random access preamble (Msg1), the RAR message (Msg2) including an RAR uplink (UL) grant; and
configuring the UE for an initial transmission of a physical uplink shared channel (PUSCH) scheduled by the RAR UL grant,
wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is to configure the UE to repeat the initial transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number,
wherein when the PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is configured to determine the Msg3 PUSCH repetition number from two most significant bits in a modulation and coding scheme (MCS) field of the RAR UL grant, the MCS for the PUSCH determined from least-significant bits in the MCS field,
wherein when the PUSCH repetition Type A is scheduled by a downlink control information (DCI) format 0_1, the processing circuitry is to configure the UE to repeat the initial transmission of the PUSCH based on a PUSCH aggregation factor received via radio resource control (RRC) signalling, and
wherein the memory is configured to store the random access preamble.
2. The apparatus of claim 1 , wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant when the UE is configured for frequency hopping by a frequency hopping flag of the RAR UL grant, the processing circuitry is to configure the UE to perform inter-slot frequency hopping for the Msg3 PUSCH repetition.
3. The apparatus of claim 2 , wherein the DCI format 0_1 is received in a physical downlink control channel (PDCCH) with cyclic redundancy code (CRC) scrambled by a Radio Network Temporary Identifier (RNTI).
4. The apparatus of claim 3 , wherein for transmission of the PUSCH with PUSCH repetition TYPE A that is scheduled by a DCI format 0_0 with CRC scrambled by a Temporary Cell RNTI (TC-RNTI), the processing circuitry is to configure the UE to repeat the transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number determined from two bits in a field of the DCI format 0_0.
5. The apparatus of claim 4 , wherein the processing circuitry is configured to determine different PRACH occasions to use for transmission of the PRACH to indicate different coverage statuses based on remaining minimum system information (RMSI).
6. The apparatus of claim 1 , wherein the wherein the processing circuitry includes a baseband processor.
7. A non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a user equipment (UE), the processing circuitry configured to perform a random access procedure comprising:
configuring the UE for transmission of a random access preamble (Msg1) in a physical random access channel (PRACH);
configuring the UE for reception of a random access response (RAR) message (Msg2) in response to transmission of the random access preamble (Msg1), the RAR message (Msg2) including an RAR uplink (UL) grant; and
configuring the UE for an initial transmission of a physical uplink shared channel (PUSCH) scheduled by the RAR UL grant,
wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is to configure the UE to repeat the initial transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number, and
wherein when the PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is configured to determine the Msg3 PUSCH repetition number from two most significant bits in a modulation and coding scheme (MCS) field of the RAR UL grant, the MCS for the PUSCH determined from least-significant bits in the MCS field, and
wherein when the PUSCH repetition Type A is scheduled by a downlink control information (DCI) format 0_1, the processing circuitry is to configure the UE to repeat the initial transmission of the PUSCH based on a PUSCH aggregation factor received via radio resource control (RRC) signalling.
8. The non-transitory computer-readable storage medium of claim 7 , wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant when the UE is configured for frequency hopping by a frequency hopping flag of the RAR UL grant, the processing circuitry is to configure the UE to perform inter-slot frequency hopping for the Msg3 PUSCH repetition.
9. The non-transitory computer-readable storage medium of claim 8 , wherein the DCI format 0_1 is received in a physical downlink control channel (PDCCH) with cyclic redundancy code (CRC) scrambled by a Radio Network Temporary Identifier (RNTI).
10. The non-transitory computer-readable storage medium of claim 9 , wherein for transmission of the PUSCH with PUSCH repetition TYPE A that is scheduled by a DCI format 0_0 with CRC scrambled by a Temporary Cell RNTI (TC-RNTI), the processing circuitry is to configure the UE to repeat the transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number determined from two bits in a field of the DCI format 0_0.
11. The non-transitory computer-readable storage medium of claim 10 , wherein the processing circuitry is configured to determine different PRACH occasions to use for transmission of the PRACH to indicate different coverage statuses based on remaining minimum system information (RMSI).
12. A non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of gNodeB (gNB), wherein to perform a random access procedure with a user equipment (UE), the processing circuitry is configured to:
decode random access preamble (Msg1) in a physical random access channel (PRACH) from the UE;
encode a random access response (RAR) message (Msg2) in response to the random access preamble (Msg1), the RAR message (Msg2) including an RAR uplink (UL) grant; and
decode an initial transmission of a physical uplink shared channel (PUSCH) scheduled by the RAR UL grant,
wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is decode repetitions of the initial transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number, and
wherein when the PUSCH repetition Type A that is scheduled by the RAR UL grant, the processing circuitry is configured to indicate to the UE the Msg3 PUSCH repetition number in two most significant bits in a modulation and coding scheme (MCS) field of the RAR UL grant, the MCS for the PUSCH determined from the least-significant bits in the MCS field,
wherein for PUSCH repetition Type A that is scheduled by a downlink control information (DCI) format 0_1, the processing circuitry is to encode radio resource control (RRC) signalling with a PUSCH aggregation factor for transmission to the UE to configure the UE to repeat the initial transmission of the PUSCH, and
wherein memory is configured to store the random access preamble.
13. The non-transitory computer-readable storage medium of claim 12 , wherein for PUSCH repetition Type A that is scheduled by the RAR UL grant when the UE is configured for frequency hopping by a frequency hopping flag of the RAR UL grant, the processing circuitry is to configure the UE to perform inter-slot frequency hopping for the Msg3 PUSCH repetition by setting the frequency hopping flag of the RAR UL grant.
14. The non-transitory computer-readable storage medium of claim 13 , wherein the processing circuitry is configured to transmit the DCI format 0_1 in a physical downlink control channel (PDCCH) with a cyclic redundancy code (CRC) scrambled by a Radio Network Temporary Identifier (RNTI).
15. The non-transitory computer-readable storage medium of claim 14 , wherein for PUSCH repetition TYPE A that is scheduled by a DCI format 0_0 with CRC scrambled by a Temporary Cell RNTI (TC-RNTI), the processing circuitry is to encode the DCI format 0_0 to configure the UE to repeat the transmission of the PUSCH over a number of slots based on a Msg3 PUSCH repetition number indicated in two bits in a field of the DCI format 0_0.