DCI Format Indication for Multicast PDSCH Decoding
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately distinguishing between point-to-point and point-to-multipoint transmission schemes for multicast communications, leading to difficulties in decoding physical downlink shared channels due to ambiguous radio network temporary identifiers.
Innovation Solution
Implementing distinct radio network temporary identifiers (RNTIs) for different transmission schemes, such as using a group-common RNTI for point-to-multipoint transmissions and a UE-specific RNTI for point-to-point transmissions, along with configuring HARQ process numbers and frequency resources to differentiate between these schemes, and optionally including a transmission type or scheme field in the DCI format.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single DCI format is used for scheduling PDSCH, then device complexity is reduced, but the ability to distinguish between multicast and unicast transmission schemes deteriorates
Solution Approach 1:
The patent applies local quality by using different RNTI scrambling for different parts of the DCI format. Specifically, the CRC bits are scrambled with different RNTIs (e.g., G-RNTI for multicast, C-RNTI for unicast) depending on the transmission type, allowing local differentiation without changing the overall DCI structure
Solution Approach 2:
The patent changes the parameter of RNTI used for CRC scrambling to distinguish between transmission types. By varying the RNTI parameter (using group RNTI for multicast vs. UE-specific RNTI for unicast), the system achieves clear identification without introducing new DCI formats
2Measurement precision
If blind detection effort is increased to distinguish transmission schemes, then transmission scheme identification accuracy is improved, but processing time increases
Solution Approach 1:
The patent uses CRC scrambling with different RNTIs as a feedback mechanism. The UE can quickly identify the transmission type by checking which RNTI matches the scrambled CRC, eliminating the need for extensive blind detection and reducing decoding time
3Measurement precision
If new DCI formats are introduced to differentiate transmission schemes, then transmission scheme identification accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing DCI format universal by using the same DCI structure for both multicast and unicast transmissions, differing only in the RNTI used for CRC scrambling. This multi-functionality approach avoids introducing new DCI formats while maintaining clear differentiation
Data Source
AI summary
Embodiments of the present disclosure relate to multicast transmissions. According to some embodiments of the disclosure, a method may include: receiving a downlink control information (DCI) format for scheduling a physical downlink shared channel (PDSCH); determining, based on the DCI format, whether the PDSCH is scheduled for a group of UEs including the UE or specifically for the UE; and decoding the scheduled PDSCH.