1024-QAM MCS Table Design for NR PDSCH Throughput
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Solution Overview
Problem
Current New Radio (NR) releases do not support 1024-constellation Quadrature Amplitude Modulation (1024-QAM), which is necessary for enhanced peak throughputs and spectral efficiency, due to differences in MCS table design and signaling compared to LTE specifications.
Innovation Solution
A new MCS table for NR is proposed, including separate Radio Network Temporary Identifiers (RNTI) for indicating 1024-QAM usage, and Limited Buffer Rate Matching (LBRM) is improved to allow larger reference transport block sizes for non-fallback DCI formats, enabling 1024-QAM support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 1024-QAM is enabled in NR, then peak throughput and spectral efficiency are improved, but the complexity of MCS table design and signaling increases due to differences from LTE specifications
Solution Approach 1:
The patent segments the MCS table into multiple versions (e.g., 64-QAM table, 256-QAM table, 1024-QAM table) with different structures and parameter mappings. Each table is optimized for its specific modulation order, allowing the system to select the appropriate table based on channel conditions and capability, thereby managing complexity through modular design rather than a single universal table
Solution Approach 2:
The patent introduces a new dimension of modulation order (Qm) as a configurable parameter that extends beyond traditional 64-QAM and 256-QAM to include 1024-QAM. This dimensional extension requires new MCS tables with expanded indexing and mapping relationships, transforming the problem from a fixed two-dimensional MCS structure to a multi-dimensional structure that accommodates higher-order modulation
2Productivity
If 1024-QAM is enabled in NR, then spectral efficiency is improved, but the existing MCS table mapping between MCS index and transport block size becomes incompatible
Solution Approach 1:
The patent changes key parameters of the MCS table structure to accommodate 1024-QAM, including the modulation order parameter (Qm), coding rate ranges, and the mapping relationship between MCS index and transport block size. These parameter changes create a new MCS table configuration that is mathematically consistent with 1024-QAM requirements while maintaining the same functional interface and signaling mechanisms
3Productivity
If 1024-QAM is enabled for PDSCH, then UE throughput is improved, but the DCI payload size and configuration complexity increase
Solution Approach 1:
The patent designs the DCI format and higher-layer parameters to be universal across different modulation orders. The same DCI structure and parameter names (e.g., mcs-Table, mcs-Table256qam, mcs-Table1024qam) are used regardless of whether 64-QAM, 256-QAM, or 1024-QAM is configured, allowing the system to indicate 1024-QAM capability through existing signaling mechanisms without requiring separate or extended DCI formats
Data Source
AI summary
Methods and apparatus for enabling 1024-constellation Quadrature Amplitude Modulation (1024-QAM) are disclosed herein. In one embodiment, a method comprises receiving information for configuring a UE to monitor a PDCCH according to two non-fallback DCI formats, and information for configuring the UE with higher-layer parameters indicating the enabling of a 1024-QAM MCS table for a serving cell. The method also comprises detecting a DCI format scheduling a PDSCH for the serving cell, wherein the DCI format comprises an MCS index; determining a transport block size (TBS) of the PDSCH using the MCS index and the 1024-QAM MCS table; determining a reference block size for LBRM for a transport block on the PDSCH based on a reference modulation order based on the higher-layer parameters; receiving the PDSCH on a Downlink (DL) Bandwidth Part (BWP); and decoding the PDSCH based on the determined TBS and the determined reference block size for LBRM.