PUSCH Modulation Symbol Mapping on Unlicensed Carriers
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Solution Overview
Problem
In LTE/NR systems operating on unlicensed carriers, the conventional modulation symbol mapping approach can result in incomplete transmission of PUSCH data when the UE switches from the first to the second candidate starting point, leading to decoding failures due to non-transmission of code blocks mapped only to the first slot, which compromises the integrity of the transport block.
Innovation Solution
A method for modulation symbol mapping that allows PUSCH modulation symbols to be mapped onto both the first and second slots of a subframe, ensuring that each code block is partially transmitted on both slots, thereby ensuring the radio base station can correctly decode the PUSCH data even if transmission starts from the second candidate starting point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE maps PUSCH modulation symbols only to the first slot and switches to the second candidate starting point, then the transmission can start later avoiding interference, but the code blocks mapped only to the first slot are not transmitted causing decoding failures
Solution Approach 1:
The patent segments the PUSCH transmission by dividing code blocks into two groups: those that can be transmitted from the second candidate starting point and those that require the first slot. This segmentation allows the UE to identify and transmit only the necessary code blocks when switching starting points, preventing decoding failures while minimizing transmission delay.
Solution Approach 2:
The patent performs preliminary mapping of PUSCH modulation symbols to both the first and second slots before transmission. This preliminary action ensures that when the UE needs to switch to the second candidate starting point, the necessary code blocks are already prepared and mapped to the second slot, enabling immediate transmission without waiting for re-mapping.
2Adaptability or versatility
If the UE transmits PUSCH from the second candidate starting point, then the transmission can avoid channel conflicts, but the completeness of PUSCH data is compromised due to missing code blocks
Solution Approach 1:
The patent implements a dynamic PUSCH transmission mechanism where the UE can adaptively switch between the first and second candidate starting points based on channel conditions. The system dynamically determines which code blocks to transmit from each starting point, allowing flexible channel access while maintaining data integrity through selective code block transmission.
Solution Approach 2:
The patent applies different transmission strategies to different code blocks based on their mapping characteristics. Code blocks that are mapped to both slots have different transmission requirements than those mapped only to the first slot. This local quality approach allows the UE to transmit only the necessary code blocks from the second starting point, maintaining data integrity while enabling channel access flexibility.
Data Source
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AI summary
A method of mapping channel quality information, CQI, modulation symbols and Physical Uplink Shared Channel, PUSCH, modulation symbols onto resource units of an allocated subframe having a first slot and a second slot for transmission on at least one unlicensed carrier. The method comprises mapping the CQI modulation symbols onto resource units of the second slot of the allocated subframe, wherein the CQI modulation symbols are mapped from the first resource unit of the second slot in a time-first mapping; and mapping the PUSCH modulation symbols onto resource units of both the first and second slot of the allocated subframe, wherein the PUSCH modulation symbols are mapped from the first resource unit of the first slot in a time-first mapping.