Uplink transmission support for reduced capability devices in wireless communications
A reduced capacity (redcap) device may perform initial uplink communications, including transmitting a redcap physical uplink control channel (R-PUCCH), over an initial uplink bandwidth part (BWP) shared with a second device, the initial uplink BWP having a bandwidth (BW) larger than a maximum BW supported by the redcap device and smaller than or equal to a maximum BW supported by the second device. Frequency hopping operation for the redcap device may be supported for the R-PUCCH transmission through frequency division multiplexing and/or time division multiplexing settings for the resources used for the R-PUCCH transmission, and for PUCCH transmission by the second device. Restrictions may be implemented to create a gap for redcap devices to perform RF retuning between a physical RACH transmission and a subsequent physical control channel (e.g. PDCCH) monitoring for random access reception when the frequency gap is larger than the maximum BW supported by the redcap device.
1. An apparatus comprising:
a processor configured to:
cause a device having reduced capabilities relative to a second device to perform initial wireless uplink communications over an initial uplink bandwidth part (BWP) indicated in a system information block (SIB), wherein a physical resource block (PRB) index for a physical uplink control channel (PUCCH) transmission comprised in the initial wireless uplink communications is determined as one of:
an offset added to a function defined as a PUCCH resource index divided by a total number of initial cyclic shift (CS) indexes, or
a bandwidth (BW) of the initial uplink BWP minus each of the offset, the function, and the value one (1); and
wherein the offset is configured separately for the device and is not used by the second device.
2. The apparatus of claim 1 , wherein the processor is configured to further cause the device to:
perform the initial wireless uplink communications using frequency resources within the initial uplink BWP.
3. The apparatus of claim 2 , wherein the frequency resources are configured based on the PRB index.
4. The apparatus of claim 1 , wherein the offset is used to determine the resources for frequency hopping.
5. The apparatus of claim 1 , wherein the offset is explicitly configured in a PUCCH common resource information element (IE) of the SIB.
6. The apparatus of claim 1 , wherein frequency hopping for the device is disabled.
7. The apparatus of claim 1 , wherein the device and the second device share the initial BWP.
8. A device having reduced capabilities relative to a second device, the device comprising:
radio circuitry configured to enable wireless communications of the device; and
a processor communicatively coupled to the radio circuitry and configured to interoperate with the radio circuitry to:
perform initial wireless uplink communications over an initial uplink bandwidth part (BWP) indicated in a system information block (SIB), wherein a physical resource block (PRB) index for a physical uplink control channel PUCCH transmission comprised in the initial wireless uplink communications is determined as one of
an offset added to a function defined as a PUCCH resource index divided by a total number of initial cyclic shift (CS) indexes, or
a bandwidth (BW) of the initial uplink BWP minus each of the offset, the function, and the value one (1); and
wherein the offset is configured separately for the device and is not used by the second device.
9. The device of claim 8 , wherein the processor is configured to further interoperate with the radio circuitry to:
perform a PUCCH transmission using specific resources that are time-division multiplexed with PUCCH resources used by the second device within the initial uplink BWP when the device shares the initial BWP with the second device.
10. The device of claim 9 , wherein the time-division multiplexed PUCCH resources are exclusively reserved for the PUCCH transmission of the device within the initial uplink BWP.
11. The device of claim 9 , wherein at least a first portion of the specific resources is shared with the second device during a first frequency hop and wherein a second portion of the specific resources is reserved for use by the device during a second frequency hop.
12. The device of claim 9 , wherein the specific resources are shared between the device and the second device for respective transmissions of the PUCCH by the device and another PUCCH by the second device.
13. The device of claim 9 , wherein the specific resources for the device are mapped to resource blocks (RBs) that do not overlap in the frequency domain with RBs of resources used by the second device to perform its own PUCCH transmission in the initial uplink BWP.
14. The device of claim 9 , wherein the processor is configured to further interoperate with the radio circuitry to perform the PUCCH transmission via at least a first frequency hop and a second frequency hop, wherein certain symbols of the first frequency hop and certain symbols of the second frequency hop are punctured to create a switching gap of a specified length between the first frequency hop and the second frequency hop.
15. The device of claim 9 , wherein the specific resources are included in a single slot that also includes time-division multiplexed resources for initial uplink transmissions performed by the second device.
16. A non-transitory memory element storing instructions executable by a processor to cause a device having reduced capabilities relative to a second device to:
perform initial wireless uplink communications over an initial uplink bandwidth part (BWP) indicated in a system information block (SIB), wherein a physical resource block (PRB) index for a physical uplink control channel (PUCCH) transmission comprised in the initial wireless uplink communications is determined as one of:
an offset added to a function defined as a PUCCH resource index divided by a total number of initial cyclic shift (CS) indexes, or
a bandwidth (BW) of the initial uplink BWP minus each of the offset, the function, and the value one (1); and
wherein the offset is configured separately for the device and is not used by the second device.
17. The non-transitory memory element of claim 16 , wherein a random access response (RAR) window, for the device monitoring a physical downlink control channel (PDCCH) subsequent to a random access procedure for a corresponding RAR, is configured to start at a first symbol of an earliest control resource set on which the device is set to receive the PDCCH.
18. The non-transitory memory element of claim 17 , wherein the earliest control resource set is located at least a specified number of symbols after a last symbol of an associated physical random access channel (PRACH) occasion.
19. The non-transitory memory element of claim 18 , wherein a value of the specified number is hard-encoded or reported by the device via a user equipment (UE) capability report by selecting one from a set of values configured via RRC signaling.
20. The non-transitory memory element of claim 18 , wherein a value of the specified number is determined to create a gap that is required to perform an RF retuning operation for the device when the gap between a central frequency of the PRACH occasion and a central frequency of an associated CORESET is larger than a maximum BW supported by the device.