PUSCH MCS Table Selection via Transform Precoding
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Solution Overview
Problem
Current wireless communication systems, particularly in the context of LTE and emerging New Radio (NR) standards, face challenges in efficiently managing communication processes, especially in scenarios requiring enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliable and Low Latency Communication (URLLC), due to complexities in scheduling and modulation schemes for physical uplink shared channels (PUSCH).
Innovation Solution
The proposed solution involves a terminal apparatus and base station apparatus that utilize transform precoding for PUSCH, with modulation schemes determined by specific MCS tables and field values based on DCI formats scrambled with different temporary identifiers (TC-RNTI and C-RNTI), enabling efficient communication by optimizing modulation and coding rates based on enabled/disabled transform precoding and higher layer parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple MCS tables are used to support different transform precoding modes, then communication efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic MCS table selection based on transform precoding configuration. The terminal determines which MCS table to use by checking the transform precoding enable/disable status, allowing the system to adaptively switch between different modulation schemes (QPSK, 16QAM, 64QAM, 256QAM) and coding rates according to channel conditions and transform precoding mode, thereby improving communication efficiency without requiring manual configuration
Solution Approach 2:
The patent changes the parameter selection logic by introducing conditional branching based on transform precoding status and DCI format type. When transform precoding is enabled and DCI format includes TC-RNTI, the first MCS table is used; when transform precoding is enabled and DCI format includes C-RNTI with specific higher layer parameters, the second MCS table is used. This parameter-based selection mechanism resolves the contradiction by automating the choice between different modulation schemes
2Productivity
If transform precoding is enabled for PUSCH, then spectral efficiency is improved, but scheduling complexity increases
Solution Approach 1:
The patent segments the MCS table selection process into distinct branches based on transform precoding status. By dividing the scheduling logic into separate paths (transform precoding enabled vs. disabled), the system can apply appropriate MCS tables without requiring complex cross-table comparisons. This segmentation simplifies the scheduling complexity while maintaining the spectral efficiency benefits of transform precoding
Solution Approach 2:
The patent performs preliminary determination of the MCS table based on transform precoding configuration before actual scheduling takes place. The terminal pre-establishes the mapping between transform precoding status and MCS tables, so that when scheduling occurs, the appropriate table is already identified. This preliminary action reduces the computational burden during real-time scheduling operations
3Reliability
If different DCI formats with different CRC scrambling are used, then communication reliability is improved, but information processing complexity increases
Solution Approach 1:
The patent applies different MCS tables to different local conditions defined by DCI format types and CRC scrambling identifiers. Instead of using a single unified MCS table for all DCI formats, the system tailors the MCS table selection to the specific local context (TC-RNTI vs. C-RNTI, transform precoding enabled vs. disabled). This local quality approach improves reliability by optimizing modulation schemes for each specific communication scenario while keeping the processing logic organized and manageable
Data Source
AI summary
Transform precoding is applied to the complex value modulation symbol in a case that transform precoding is enabled for PUSCH, the prescribed modulation scheme is provided based at least on a first MCS table and an MCS field value included in the DCI format in a case that the DCI format includes a CRC scrambled by a TC-RNTI and the transform precoding is enabled for the PUSCH, and the prescribed modulation scheme is provided based on at least a second MCS table and/or the MCS field value in a case that the DCI format is a first uplink DCI format with the CRC scrambled by a C-RNTI, the transform precoding is enabled for the PUSCH, and a higher layer parameter MCS-Table-PUSCH-tp is set to a first value.