Method and apparatus for NACK-only reporting in RRC idle and inactive states

1 . A method implemented by a user equipment (UE), the method comprising:

receiving, from a serving node and via a new radio (NR) radio access network (RAN), at least one physical downlink shared channel (PDSCH) transport block;

determining that a first PDSCH transport block is decoded erroneously during a UE radio resource control (RRC) idle state or a UE RRC inactive state;

generating a hybrid automatic repeat request (HARQ) information report indicating a negative acknowledgement (NACK) of the first PDSCH transport block;

performing NACK-only reporting to the serving node;

determining that a second PDSCH transport block is decoded correctly during the UE RRC idle state or the UE RRC inactive state; and

determining an absence of transmitting a HARQ information report indicating an acknowledgement (ACK) of the second PDSCH transport block;

wherein performing the NACK-only reporting comprises:

selecting a PUCCH resource from a PUCCH allocation;

generating a pseudo-random sequence, wherein a length of the pseudo-random sequence is equal to a total number N of sub-carriers of one RB of the selected PUCCH resource;

performing cyclic shifts upon the generated pseudo-random sequence to derive N cyclic shift hopping pseudo-random sequences of different offsets;

mapping N elements of each of the N cyclic shift hopping pseudo-random sequences to a the N sub-carriers of a same RB of the selected PUCCH resource to obtain N effective PUCCH resources corresponding to the same RB; and

transmitting M NACK-only reports at the same time by using M of the N effective PUCCH resources corresponding to the same RB of the selected PUCCH resource, wherein M is an integer greater than 1 and less than or equal to N.

2 . The method of claim 1 , wherein a physical uplink control channel (PUCCH) allocation to the UE configured at the serving node includes a PUCCH resource or a set of PUCCH resources numbered at a configured PUCCH count, a PUCCH resource of the PUCCH allocation comprising one resource block in a frequency domain and comprising at least one orthogonal frequency division multiplexing (OFDM) symbol in a time domain, the resource block comprising a plurality of sub-carriers (SCs) numbered at a SC count.

3 . The method of claim 2 , wherein the at least one PDSCH transport block received by the user equipment comprises one transport block, the PUCCH allocation comprises a set of PUCCH resources, and the generated HARQ information report includes one bit that indicates a decoding status of the transport block;

one PUCCH resource outside of the PUCCH allocation is reserved as a reference resource, the reference resource is configured to be not selectable by any UE to transmit the HARQ information report and is used to provide a reference energy level for comparing with energy level of a PUCCH resource that is selectable by UEs for transmitting HARQ information report.

4 . The method of claim 3 , further comprising:

determining a timing value corresponding to the selected PUCCH resource; and

transmitting the HARQ information report through the selected PUCCH resource according to the timing value.

5 . The method of claim 4 , wherein determining a timing value corresponding to the selected PUCCH resource further comprises:

receiving, from the serving node, a synchronization signal block (SSB) and/or a physical downlink shared channel; and

determining the timing value corresponding to the selected PUCCH resource according to a receive timing of the SSB and/or physical downlink shared channel; or determining a timing value corresponding to the selected PUCCH resource further comprises:

receiving, from the serving node, a set of at least one timing value corresponding to a set of at least one range of reference signal received power (RSRP) values or thresholds;

measuring a reference signal received power level; and

determining the timing value corresponding to the selected PUCCH resource according to the measured reference signal received power level and the provided set of at least one range of reference signal received power values or thresholds;

wherein the provided set of at least one timing value corresponding to the set of at least one range of RSRP values or thresholds are RRC configured and/or indicated in downlink control information (DCI); or

determining a timing value corresponding to the selected PUCCH resource further comprises:

determining the timing value corresponding to a latest timing value provided by the serving node during a RRC connected state; or

determining a timing value corresponding to the selected PUCCH resource further comprises:

receiving, from the serving node, a timing offset between a global navigation satellite system (GNSS) timing and system frame or slot number or boundary;

deriving a time stamp for a received downlink signal or channel;

calculating a propagation delay according to the GNSS timing offset and the time stamp; and

determining the timing value according to the propagation delay,

wherein the GNSS timing offset is RRC configured or indicated in DCI.

6 . The method of claim 3 , further comprising:

determining a power level corresponding to the selected PUCCH resource; and

transmitting the HARQ information report through the selected PUCCH resource according to the power level.

7 . The method of claim 6 , wherein determining a power level corresponding to the selected PUCCH resource further comprises:

receiving, from the serving node, at least one of a synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS) and a transmitting power thereof;

measuring a received power of the at least one of SSB or CSI-RS;

calculating a pathloss according to at least the transmitting power and the received power of the at least one of SSB or CSI-RS; and

determining the power level corresponding to the selected PUCCH resource according to at least the pathloss and a target received power,

wherein the target received power is RRC configured or indicated in DCI by the serving node; or

determining a power level corresponding to the selected PUCCH resource further comprises:

receiving, from the serving node, a range of transmission power levels and a set of corresponding RSRP threshold values;

measuring a reference signal received power level; and

determining the power level corresponding to the selected PUCCH resource according to the measured reference signal received power level and the set of RSRP threshold values; or

determining a power level corresponding to the selected PUCCH resource further comprises:

determining the power level corresponding to a latest power level provided by the serving node during a RRC connected state.

8 . The method of claim 7 , further comprising:

generating the HARQ information report including two bits that indicate the decoding status of the two transport blocks;

determining a subset of PUCCH resources from the three subsets of PUCCH resources according to the decoding status of the two transport blocks;

selecting one PUCCH resource from the determined subset of PUCCH resources; and

transmitting, to the serving node, one among up to a SC count of possible cyclic shift hopping pseudo-random sequences representing the HARQ information report through the selected PUCCH resource.

9 . The method of claim 1 , wherein the at least one PDSCH transport block received by the user equipment comprises two transport blocks, and the configured PUCCH allocation comprises three non-overlapping subsets of PUCCH resources, the three non-overlapping subsets of PUCCH resources being respectively designated for transmitting different HARQ information reports indicating different decoding statuses of the two transport blocks.

10 . The method of claim 9 , wherein the two transport blocks including a first transport block and a second transport block, a first subset of the three non-overlapping subsets of PUCCH resources is designated for only transmitting the HARQ information report indicating the first transport block being decoded erroneously;

a second subset of the three non-overlapping subsets of PUCCH resources is designated for only transmitting the HARQ information report indicating the second transport block being decoded erroneously; and

a third subset of the three non-overlapping subsets of PUCCH resources is designated for only transmitting the HARQ information report indicating the first transport block and the second transport block being decoded erroneously.

11 . A user equipment (UE) comprising:

one or more processors; and

memory coupled to the one or more processors, the memory storing thereon computer-readable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations, the operations comprising:

receiving, from a serving node and via a new radio (NR) radio access network (RAN), at least one physical downlink shared channel (PDSCH) transport block;

determining that a first PDSCH transport block is decoded erroneously during a UE radio resource control (RRC) idle state or a UE RRC inactive state;

generating a hybrid automatic repeat request (HARQ) information report indicating a negative acknowledgement (NACK) of the first PDSCH transport block;

performing NACK-only reporting to the serving node;

determining that a second PDSCH transport block is decoded correctly during the UE RRC idle state or the UE RRC inactive state; and

determining an absence of transmitting a HARQ information report indicating an acknowledgement (ACK) of the second PDSCH transport block;

wherein performing the NACK-only reporting comprises:

selecting a PUCCH resource from a PUCCH allocation;

generating a pseudo-random sequence, wherein a length of the pseudo-random sequence is equal to a total number N of sub-carriers of one RB of the selected PUCCH resource;

performing cyclic shifts upon the generated pseudo-random sequence to derive N cyclic shift hopping pseudo-random sequences of different offsets;

mapping N elements of each of the N cyclic shift hopping pseudo-random sequences to the N sub-carriers of a same RB of the selected PUCCH resource to obtain N effective PUCCH resources corresponding to the same RB; and

transmitting M NACK-only reports at the same time by using M of the N effective PUCCH resources corresponding to the same RB of the selected PUCCH resource, wherein M is an integer greater than 1 and less than or equal to N.

12 . A method implemented by a serving node, the method comprising:

transmitting, to a user equipment (UE) and via a new radio (NR) radio access network (RAN), at least one physical downlink shared channel (PDSCH) transport block;

receiving, from the UE, a hybrid automatic repeat request (HARQ) information report indicating a negative acknowledgement (NACK) of a first PDSCH transport block, the first PDSCH transport block being decoded erroneously during a UE radio resource control (RRC) idle state or a UE RRC inactive state;

retransmitting, to the UE, the first PDSCH transport block; and

providing, to the UE, a physical uplink control channel (PUCCH) allocation for performing NACK-only reporting, wherein

retransmitting, to the UE, the first PDSCH transport block; and

transmitting a HARQ information report indicating an acknowledgement (ACK) of a second PDSCH transport block for correctly decoding is absent during the UE RRC idle state or the UE RRC inactive state;

wherein performing the NACK-only reporting comprises:

selecting a PUCCH resource from the PUCCH allocation;

generating a pseudo-random sequence, wherein a length of the pseudo-random sequence is equal to a total number N of sub-carriers of one RB of the selected PUCCH resource;

performing cyclic shifts upon the generated pseudo-random sequence to derive N cyclic shift hopping pseudo-random sequences of different offsets;

mapping N elements of each of the N cyclic shift hopping pseudo-random sequences to the N sub-carriers of a same RB of the selected PUCCH resource to obtain N effective PUCCH resources corresponding to the same RB; and

transmitting M NACK-only reports at the same time by using M of the N effective PUCCH resources corresponding to the same RB of the selected PUCCH resource, wherein M is an integer greater than 1 and less than or equal to N.

13 . The method of claim 12 , wherein:

the PUCCH allocation including a PUCCH resource or a set of PUCCH resources numbered at a configured PUCCH count, and a PUCCH resource of the PUCCH allocation comprising at least one resource block in a frequency domain and comprising at least one orthogonal frequency division multiplexing (OFDM) symbol in a time domain, the resource block comprising a plurality of sub-carriers (SCs) numbered at a SC count, wherein the configured PUCCH count is less than the SC count.

14 . The method of claim 13 , further comprising:

reserving one PUCCH resource outside of the PUCCH allocation as a reference resource, the reference resource is configured to be not selectable by any UE to transmit the HARQ information report and is used to provide a reference energy level for comparing with energy level of a PUCCH resource that is selectable by UEs for transmitting HARQ information report.

15 . The method of claim 13 , further comprising:

indicating, to the UE and in downlink control information (DCI), a PUCCH resource from the PUCCH allocation to be selected for performing NACK-only reporting; and

receiving, from the UE and via the PUCCH resource, the HARQ information report indicating NACK of the first PDSCH transport block.

16 . The method of claim 15 , further comprising:

transmitting, to the UE, at least one of a synchronization signal block (SSB) or a physical downlink shared channel for determining a time value corresponding to the PUCCH resource; or

transmitting, to the UE, a set of at least one timing value corresponding to a set of at least one range of reference signal received power (RSRP) values or thresholds for determining a time value corresponding to the PUCCH resource,

wherein the set of at least one timing value corresponding to the set of at least one range of RSRP values or thresholds are radio resource control (RRC) configured and/or indicated in the downlink control information (DCI); or

transmitting, to the UE, a timing offset between a global navigation satellite system (GNSS) timing and system frame or slot number or boundary for determining a time value corresponding to the PUCCH resource.

17 . The method of claim 16 , further comprising:

receiving, from the UE and via the PUCCH resource, the HARQ information report indicating NACK of the first PDSCH transport block according to the timing value.

18 . The method of claim 16 , further comprising:

receiving, from the UE and via the PUCCH resource, the HARQ information report indicating NACK of the first PDSCH transport block according to the power level.

19 . The method of claim 15 , further comprising:

transmitting, to the UE, at least one of a synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS) and a transmitting power thereof for determining a power level corresponding to the PUCCH resource; or

transmitting, to the UE, a range of transmission power levels and a set of corresponding RSRP threshold values for determining a power level corresponding to the PUCCH resource.