Cross-Carrier HARQ Entity for URLLC Reliability
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Solution Overview
Problem
In LTE systems, carrier aggregation technologies fail to achieve the required reliability for ultra-reliable and low-latency communication (URLLC) services due to independent HARQ entities on each component carrier, which limits the ability to distinguish relationships among data packets carrying transport blocks across different carriers, leading to insufficient redundancy and increased error rates.
Innovation Solution
The solution involves assigning a shared HARQ process number based on the frequency band for data packets carrying the same transport blocks across multiple frequency bands, allowing joint decoding and increasing redundancy, thereby improving data transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent HARQ entities are used on each component carrier in carrier aggregation, then device complexity is reduced and operation is simplified, but transmission reliability is insufficient for URLLC services
Solution Approach 1:
The patent merges HARQ entities across multiple component carriers by introducing a cross-carrier HARQ entity that manages HARQ processes for multiple carriers. This allows data packets from different carriers to be jointly decoded, improving transmission reliability through combined redundancy while maintaining manageable complexity through centralized control.
Solution Approach 2:
The patent creates a universal HARQ entity structure that can operate across multiple component carriers with different configurations. The cross-carrier HARQ entity provides multi-functional capabilities by handling HARQ processes for various carriers using a unified framework, enabling flexible adaptation to different service requirements including URLLC.
2Loss of information
If separate HARQ processes are used for each component carrier, then carrier aggregation operation is simplified, but the ability to distinguish relationships among data packets carrying transport blocks across different carriers is limited
Solution Approach 1:
The patent introduces a cross-carrier HARQ entity as an intermediary that mediates between multiple component carriers and the terminal device. This intermediary maintains mapping relationships between transport blocks and their corresponding data packets across carriers, enabling the terminal to correctly identify and associate data packets from different carriers without complicating carrier aggregation operation.
Solution Approach 2:
The patent changes the HARQ process parameter structure by introducing cross-carrier HARQ process identifiers and mapping relationships. This allows the system to track and distinguish data packets across carriers using modified parameter representations, improving relationship identification while maintaining operational simplicity through standardized parameter management.
3Reliability
If redundant information is increased in data packets to improve reliability, then transmission reliability improves, but signaling overhead increases
Solution Approach 1:
The patent segments redundancy distribution across multiple component carriers rather than concentrating all redundancy in a single carrier. By dividing the transport block transmission across multiple carriers with distributed redundancy, the system achieves improved reliability through diversity while reducing per-packet signaling overhead, as each carrier carries a portion of the redundant information.
Data Source
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AI summary
Embodiments of the present invention provide a communication method and an apparatus. In the method and the apparatus, a terminal device receives first downlink control information from a network device, where the first downlink control information includes a first hybrid automatic repeat request HARQ process number. The terminal device receives, on a first frequency band, a first data packet carrying a first transport block, and receives, on a second frequency band, a second data packet carrying a second transport block, where the first HARQ process number corresponds to the first transport block on the first frequency band and the second transport block on the second frequency band. The terminal device performs joint decoding on the first data packet and the second data packet. The first transport block is the same as the second transport block. By using the method and the apparatus provided in the embodiments of the present invention, data transmission reliability in a multi-band transmission scenario can be improved.