Adaptive Downlink Control Channel for HARQ Code Rate Switching
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G networks, face challenges in efficiently managing downlink control channels due to varying code rates and channel conditions, leading to suboptimal performance in error correction and data transmission.
Innovation Solution
An adaptive downlink control channel structure that dynamically switches between Chase combining and Incremental Redundancy Hybrid Automatic Repeat Request (HARQ) techniques, selecting appropriate forward error correction codes based on code rates and channel conditions, and selectively incorporating redundancy version indicators to optimize transport block sizes and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed forward error correction code is used for downlink control information, then the system structure is simple, but the error correction efficiency is suboptimal under varying channel conditions
Solution Approach 1:
The patent implements dynamic selection of forward error correction codes based on channel conditions and code rates. The system transitions from a static FEC code configuration to a dynamic one where the appropriate code (e.g., polar codes, LDPC codes, Turbo codes) is selected according to the detected channel state, thereby optimizing error correction efficiency without requiring overly complex predetermined structures
Solution Approach 2:
The system changes the parameters of the forward error correction code selection based on varying channel conditions and code rates. By monitoring channel quality metrics and adjusting the FEC code parameters dynamically, the system achieves improved reliability while maintaining manageable complexity through parameter adaptation rather than structural overhaul
2Reliability
If redundancy version indicators are always included in transport blocks, then decoding accuracy is improved, but transport block size and resource usage increase
Solution Approach 1:
The patent applies redundancy version indicators selectively rather than uniformly across all transport blocks. The system determines the presence of RV indicators based on local conditions such as the specific code rate and forward error correction code being used, thereby providing decoding accuracy where needed while minimizing unnecessary overhead in cases where it is not required
Solution Approach 2:
Instead of always including redundancy version indicators (excessive action), the system includes them only when necessary for accurate decoding (partial action). This selective approach ensures that the benefits of improved decoding accuracy are achieved without the constant penalty of increased transport block size and resource consumption
3Reliability
If Chase combining HARQ is used for all code rates, then the implementation is simple, but performance is suboptimal for lower code rates where incremental redundancy is more effective
Solution Approach 1:
The patent implements dynamic HARQ scheme selection that transitions from a static Chase combining approach to a dynamic system that chooses between Chase combining and Incremental Redundancy based on the code rate and channel conditions. This dynamic adaptation allows the system to achieve optimal performance across different operating conditions without requiring overly complex predetermined HARQ structures
Solution Approach 2:
The system changes the HARQ implementation parameters based on the code rate being used. For higher code rates, Chase combining is selected for its simplicity and effectiveness, while for lower code rates, Incremental Redundancy is selected to maximize reliability. This parameter adaptation resolves the contradiction by matching the HARQ complexity to the actual performance requirements of each code rate scenario
Data Source
AI summary
An adaptive downlink control channel structure is provided to enable a transmitter to switch between forward error correction codes that use either Chase combining or incremental redundancy hybrid automatic repeat request (HARQ) techniques. Chase combining HARQ can be more efficient for forward error correction codes that use higher code rates, while incremental redundancy can be more effective for forward error correction codes that use lower code rates. The transmitter will also selectively comprise the redundancy version indicator bits depending on the HARQ method selected, which can reduce the sizes of the transport blocks when not using incremental redundancy. A receiver device can also decode transport blocks and determine whether a redundancy version indicator is present based on the forward error correction code selected.