Dynamic DCI Bit Repurposing for 5G NR TCI State Indication
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Solution Overview
Problem
5G NR systems lack flexibility in triggering sounding reference signal (SRS) transmissions and indicating downlink (DL) or uplink (UL) transmission configuration indicator (TCI) states, limiting their performance and adaptability.
Innovation Solution
Repurposing unused bits in DCI formats 0_1/0_2 to improve flexibility by using them for CSI-RS requests, beam indication, and TCI state indication, allowing for aperiodic CSI-RS/CSI-IM transmissions and dynamic resource allocation without scheduling PUSCH or SRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DCI formats are used with traditional bit interpretations for scheduling PUSCH or triggering SRS, then the system maintains backward compatibility and basic functionality, but flexibility for triggering SRS transmissions and indicating TCI states is limited
Solution Approach 1:
The patent applies dynamics by making the bit interpretation in DCI formats dynamic rather than static. Specifically, the interpretation of certain bits in DCI formats 0_1 and 0_2 changes based on the value of the SRS request field. When the SRS request field indicates no SRS transmission, those bits are reinterpreted to carry TCI state information instead of their traditional scheduling-related meanings. This dynamic reinterpretation enables the system to flexibly indicate TCI states for aperiodic CSI-RS receptions without requiring separate DCI formats or additional signaling overhead.
Solution Approach 2:
The patent applies universality by enabling DCI format bits to serve multiple functions depending on the transmission context. The same bits in DCI formats 0_1 and 0_2 can traditionally be used for PUSCH scheduling parameters, but when SRS transmission is not requested, these bits universally serve the additional function of indicating TCI states. This multi-functionality allows the system to use existing DCI structures for both traditional scheduling purposes and new beam management purposes, improving versatility without increasing DCI format complexity.
2Adaptability or versatility
If separate DCI formats or additional signaling are used to indicate TCI states and trigger SRS transmissions, then flexibility and adaptability are improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent applies universality by enabling existing DCI format bits to serve multiple functions. The same bits that traditionally carried scheduling information for PUSCH can alternatively indicate TCI states when SRS transmission is not requested. This multi-functionality eliminates the need for separate DCI formats or additional signaling fields dedicated to TCI state indication, thereby reducing signaling overhead while maintaining the ability to flexibly indicate both DL and UL TCI states.
Solution Approach 2:
The patent applies parameter changes by dynamically altering the interpretation of DCI format parameters based on the SRS request field value. When the SRS request indicates no SRS transmission, the parameter interpretation changes to encode TCI state information. This parameter reinterpretation allows the system to convey TCI state information using the same signaling resources already allocated for scheduling, thereby reducing overall signaling overhead without requiring additional dedicated signaling channels or fields.
3Adaptability or versatility
If DCI formats are designed for specific functions (PUSCH scheduling, SRS triggering), then functionality is clear and reliable, but adaptability for new functions like aperiodic CSI-RS requests and beam indication is limited
Solution Approach 1:
The patent applies dynamics by implementing context-dependent bit interpretation in DCI formats. The meaning of certain bits dynamically changes based on the SRS request field value. When SRS transmission is requested, bits follow their traditional interpretation for scheduling purposes. When SRS transmission is not requested, the same bits dynamically switch to indicate TCI states and support aperiodic CSI-RS requests. This dynamic adaptation allows the DCI formats to reliably support both traditional scheduling functions and new beam management functions without ambiguity, as the interpretation context is clearly determined by the SRS request field.
Data Source
AI summary
A user equipment (UE) configured for operation in a fifth-generation (5G) new radio (NR) (5G-NR) system may decode a downlink control information (DCI) format comprising one of DCI format 0_1 and DCI format 0_2. When the DCI format does not schedule a physical uplink shared channel (PUSCH) and does not trigger a sounding reference signal (SRS) transmission, and when the DCI format at least triggers a channel state information (CSI) request including at least one of a CSI reference signal (CSI-RS) operation, a CSI interference measurement (CSI-IM), and a CSI report transmission, the UE may interpret one or more fields of the DCI format that would normally be used for PUSCH scheduling and/or SRS triggering as indicating additional information or parameters for the triggered CSI request. The UE may perform the triggered CSI request using at least the information in the one or more repurposed fields of the DCI.