Adaptive MCS Table Selection for 256 QAM LTE Downlink
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Solution Overview
Problem
Conventional LTE communication systems cannot support higher-order modulations such as 256 QAM, limiting peak data transmission rate and spectral efficiency, especially in small cell scenarios with good channel conditions.
Innovation Solution
A modulation processing method and apparatus that allows a base station to select and transmit a Modulation and Coding Scheme (MCS) table supporting M-order modulation (where M>64), enabling the use of higher-order modulations like 256 QAM by configuring different MCS tables for specific subframes and transmission types based on predefined information and channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LTE systems use low-order modulation (e.g., 64 QAM or below), then communication reliability is maintained in deep fading conditions, but peak data transmission rate and spectral efficiency are limited in good channel conditions
Solution Approach 1:
The system dynamically selects between different MCS tables (supporting M-order modulation vs. conventional modulation) based on channel conditions and transmission types. The base station configures multiple MCS tables with different modulation capabilities and selects the appropriate table adaptively, enabling the system to transition between reliable low-order modulation in poor conditions and high-rate M-order modulation in good conditions.
Solution Approach 2:
The invention changes the modulation order parameter by introducing M-order modulation (M>64, such as 256 QAM) in the enhanced MCS table. This parameter change allows the system to achieve higher spectral efficiency and data transmission rates when channel conditions permit, while maintaining compatibility with conventional modulation schemes when reliability is prioritized.
2Reliability
If conventional LTE systems use low-order modulation with large redundant error correction codes, then communication stability is guaranteed in deep fading, but system throughput improvement is restricted when signal-to-noise ratio is high
Solution Approach 1:
The system adaptively adjusts the modulation and coding parameters by selecting from multiple configured MCS tables. When channel quality is good, the system selects the enhanced MCS table supporting M-order modulation to maximize throughput. When channel quality degrades, it switches to conventional MCS tables with stronger error correction, maintaining stability while allowing throughput to scale with channel conditions.
Solution Approach 2:
The invention introduces a new parameter dimension - the modulation order M (>64) - in the enhanced MCS table. This enables the system to achieve higher spectral efficiency (e.g., 256 QAM provides 8 bits per symbol compared to 6 bits for 64 QAM) when signal-to-noise ratio is high, directly increasing system throughput without compromising reliability in poor conditions.
3Adaptability or versatility
If the base station configures multiple MCS tables supporting different modulation orders, then flexibility and adaptability are improved, but device complexity increases
Solution Approach 1:
The MCS tables are segmented into different types: conventional MCS tables supporting traditional modulation orders and an enhanced MCS table supporting M-order modulation (M>64). Each table type is optimized for specific scenarios, allowing the system to manage complexity by dividing the modulation scheme space into distinct segments rather than using a single comprehensive table.
Solution Approach 2:
The enhanced MCS table is designed to be multi-functional, supporting both conventional modulation orders and M-order modulation (M>64) within a single table structure. This universality reduces the need for multiple separate tables and simplifies the overall system by allowing one enhanced table to serve multiple modulation requirements.
Data Source
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AI summary
The present invention provides a modulation processing method and apparatus for high-order coding, a base station and a terminal, herein the method includes: a base station selecting a Modulation and Coding Scheme (MCS) table according to a transmission type and predefined information, herein the MCS table includes a MCS table supporting a M-order modulation and a MCS table not supporting a M-order modulation, herein M>64; and the base station transmitting downlink control signaling to a terminal, the downlink control signaling including a modulation and coding scheme field IMCS, herein the IMCS is based on the MCS table supporting or not supporting a M-order modulation selected by the base station. With the above technical solutions according to the present invention, the technical problem in the related art that the conventional table cannot support a higher-order modulation is solved, thereby achieving transmission between the base station and the terminal based on the higher-order modulation.