MCS Table Selection for 256-QAM Support
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Solution Overview
Problem
Current LTE systems face challenges in supporting higher order modulation schemes like 256-QAM without requiring changes to downlink and uplink control signaling formats, which would add signaling overhead and impact uplink coverage.
Innovation Solution
Implementing a UE with table components that maintain default and secondary tables, allowing selection between them based on received DCI or RNTI, enabling support for 256-QAM without altering existing signaling formats by swapping entries in MCS and CQI tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher order modulation schemes like 256-QAM are supported by modifying control signaling formats, then spectral efficiency is improved, but signaling overhead increases and uplink coverage is impacted
Solution Approach 1:
The patent creates a secondary MCS table that copies the structure and entries of the default MCS table, allowing the system to support 256-QAM modulation without modifying the original control signaling formats. The secondary table serves as a duplicate with enhanced modulation options, enabling higher spectral efficiency while preserving backward compatibility and avoiding additional signaling overhead.
Solution Approach 2:
The patent changes the modulation order parameter in specific entries of the MCS table to support 256-QAM (modulation order 8) while keeping the table structure and signaling format unchanged. By selectively updating modulation parameters in the secondary table rather than redesigning the entire control signaling system, the patent achieves improved spectral efficiency without increasing signaling overhead.
2Productivity
If higher order modulation schemes like 256-QAM are supported by modifying control signaling formats, then spectral efficiency is improved, but device complexity increases
Solution Approach 1:
The patent creates a secondary MCS table that copies the structure and entries of the default MCS table, allowing the system to support 256-QAM modulation without modifying the original control signaling formats. The secondary table serves as a duplicate with enhanced modulation options, enabling higher spectral efficiency while preserving backward compatibility and avoiding additional signaling overhead.
Solution Approach 2:
The patent implements dynamic table selection where the UE can switch between the default MCS table and the secondary MCS table based on channel conditions and network configuration. This dynamic approach allows the system to adapt to varying spectral efficiency requirements without permanently increasing device complexity, as the UE only needs to maintain both tables and select appropriately based on current operating conditions.
3Adaptability or versatility
If default MCS table entries are modified to support 256-QAM, then support for higher modulation is achieved, but backward compatibility is lost
Solution Approach 1:
The patent segments the MCS table functionality into two separate tables: a default MCS table that maintains backward compatibility with existing systems, and a secondary MCS table that supports higher order modulation schemes like 256-QAM. This segmentation allows the system to support both legacy and advanced modulation schemes simultaneously, with the network able to select which table to use based on UE capabilities and channel conditions.
Solution Approach 2:
The patent creates a universal MCS table system where the secondary table serves multiple functions: it supports 256-QAM for UEs capable of higher order modulation, maintains the same structural format for compatibility, and can be selectively activated based on network conditions. This multi-functionality allows a single table structure to serve both legacy compatibility and advanced performance requirements.
Data Source
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AI summary
Methods, systems, and devices for modulation and coding scheme selection and configuration. A mobile communication device includes a table component, a table selection component, and a communication component. The table component is configured to maintain two or more tables each having entries for a plurality of available modulation schemes. The two or more tables include a default table and a secondary table. The default table and the secondary table have a matching number of entries, and the secondary table includes an entry corresponding to a 256-QAM scheme. The table selection component is configured to select a selected table from one of the default table and the secondary table. The communication component is configured to receive and process a communication from a base station based on a modulation and coding scheme of the selected table.