Carrier Aggregation Retransmission Mapping and HARQ Acknowledgment Distribution
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Solution Overview
Problem
In wireless communication systems with carrier aggregation, data transmission quality is compromised during retransmissions due to the use of low-quality carriers, and the transmission of HARQ acknowledgments through PUCCH or PUSCH degrades the quality of control information or data.
Innovation Solution
A method involving the use of different mapping patterns for initial and retransmitted transport blocks across component carriers, along with the transmission of HARQ acknowledgments through an uplink control channel configured to carry only these acknowledgments, distributed discontinuously in resource elements, to improve decoding quality and prevent quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same carrier is used for retransmission as in initial transmission, then the transmission process is simple, but data transmission quality deteriorates because low-quality carriers cannot successfully transmit data on retransmission
Solution Approach 1:
The patent applies dynamics by making the carrier mapping flexible and adaptable. Instead of fixed one-to-one mapping, the system dynamically selects carriers for retransmission based on current channel conditions. The eNodeB can choose different carriers for retransmission than initial transmission, and the mapping relationship can change between different transmission opportunities, allowing the system to respond to varying network conditions.
Solution Approach 2:
The patent changes the parameter of carrier mapping from static to dynamic. By introducing flexible mapping patterns where transport blocks can be mapped to different component carriers in retransmission compared to initial transmission, the system optimizes transmission quality by selecting carriers with better current conditions rather than persisting with the same carrier.
2Quantity of substance
If multiple HARQ acknowledgments are transmitted through one PUCCH, then uplink control information quantity increases, but quality of control information degrades
Solution Approach 1:
The patent segments the transmission of HARQ acknowledgments by introducing separate PUCCH resources for different sets of ACK/NACK bits. Instead of multiplexing all HARQ acknowledgments in a single PUCCH transmission, the system divides them into multiple groups, each transmitted on dedicated PUCCH resources. This segmentation prevents quality degradation by avoiding overloading a single control channel.
Solution Approach 2:
The patent uses PUSCH as an intermediary carrier to transmit HARQ acknowledgments when the number of acknowledgments exceeds what can be handled by PUCCH. By introducing PUSCH as a mediator for carrying additional ACK/NACK information, the system avoids overloading the PUCCH and maintains control information quality while still transmitting all necessary HARQ acknowledgments.
3Quantity of substance
If HARQ acknowledgments are transmitted through PUSCH, then all ACK/NACK can be transmitted, but quality of data transmitted through PUSCH degrades
Solution Approach 1:
The patent segments the transmission path by separating HARQ acknowledgment transmission from data transmission. By using dedicated PUCCH resources for ACK/NACK bits and only using PUSCH for data when necessary, the system avoids the quality degradation that would occur if HARQ acknowledgments were multiplexed with data on the same channel. This segmentation ensures that control information and data each receive appropriate transmission resources without compromising quality.
Data Source
AI summary
A method of transport block retransmission in a wireless communication system employing carrier aggregation is disclosed. A method of retransmitting transport blocks in a base station of a wireless communication system employing carrier aggregation comprises mapping each of a plurality of transport blocks to each of a plurality of component carriers using a first mapping pattern and transmitting the plurality of transport blocks to a mobile station; recognizing that the plurality of transport blocks are not transmitted successfully; and mapping each of the plurality of transport blocks to each of the plurality of component carriers using a second mapping pattern and retransmitting the plurality of transport blocks to the mobile station.