MCS Indication Reinterpretation for 256QAM Downlink Transmission
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Solution Overview
Problem
Current 3GPP LTE Release 11 technologies cannot indicate 256QAM for downlink data transmission in DCI, limiting data rate and efficiency in hot regions and future LTE Release 12 standardization.
Innovation Solution
A method and device that determine UE support for 256QAM mode and use extended or reused MCS indication information in DCI to enable 256QAM downlink data transmission, improving efficiency by reconfiguring existing MCS indication modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current 5-bit MCS indication in DCI is used, then compatibility with LTE Release 8-11 is maintained, but 256QAM cannot be indicated for downlink data transmission
Solution Approach 1:
The patent changes the interpretation parameters of existing MCS indication values. When 256QAM is supported, MCS indices 29-31 are reinterpreted to indicate 256QAM modes instead of their original 64QAM retransmission modes. This parameter reinterpretation enables 256QAM indication without changing the DCI structure or adding new bits.
Solution Approach 2:
The existing 5-bit MCS field in DCI is made multi-functional. It can indicate both traditional QPSK/16QAM/64QAM modes and the new 256QAM mode using the same bit structure. The same DCI format serves multiple modulation schemes by changing how specific index values are interpreted based on UE capability.
2Productivity
If 256QAM is introduced to increase downlink data rate, then productivity is improved, but the existing DCI MCS indication scheme becomes insufficient
Solution Approach 1:
The patent reinterprets the meaning of specific MCS index parameters (29-31) to enable 256QAM indication. By changing how these index values are mapped to modulation schemes based on UE capability, the system achieves higher data rates with 256QAM while using the existing DCI parameter structure.
3Device complexity
If existing MCS indication modes are reused for 256QAM, then device complexity is reduced, but compatibility with older LTE versions must be maintained
Solution Approach 1:
The patent uses parameter reinterpretation based on UE capability. The base station determines whether the UE supports 256QAM and accordingly changes how MCS indices 29-31 are interpreted. For 256QAM-capable UEs, these indices indicate 256QAM modes; for legacy UEs, they maintain their original meaning, ensuring backward compatibility without additional complexity.
Data Source
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AI summary
The present disclosure provides a method for indicating a modulation and coding scheme (MCS), including a step of when it is determined that a UE supports a downlink 256QAM mode, indicating the 256QAM mode using current information indicating the MCS or extended information indicating the MCS in downlink control information (DCI). The present disclosure further provides a method for receiving downlink data, including a step of, after a UE has received information indicating an MCS which includes indication information indicating a 256QAM mode, receiving the downlink data according to the 256QAM mode and a corresponding TBS index. The present disclosure further provides devices for implementing the above methods. According to the present disclosure, the UE can receive the data according to the received indication information for the 256QAM mode, so it is able to improve the data transmission efficiency.