FDD-TDD Carrier Aggregation HARQ Timing Segmentation

The patent segments the HARQ-ACK feedback mechanism by introducing separate timing indication fields for FDD and TDD component carriers. This allows independent timing configuration for each carrier type, eliminating the ambiguity that arises when FDD timing is applied to TDD SCell. The segmentation enables precise control over when HARQ-ACK feedback should be transmitted for each carrier, resolving the reliability issue while maintaining carrier aggregation flexibility.

The patent implements dynamic timing adjustment by allowing the network to independently configure HARQ timing parameters for FDD PCell and TDD SCell through separate RRC signaling. The timing can be adapted based on the specific TDD uplink-downlink configuration and FDD carrier characteristics, making the system flexible rather than static. This dynamic approach ensures reliable HARQ-ACK messaging while supporting carrier aggregation across different duplex modes.

The patent divides the HARQ timing configuration into separate segments for FDD and TDD carriers. Instead of applying a unified FDD timing rule to TDD SCell, the system maintains distinct timing configurations that can be independently adjusted. This segmentation prevents reconfiguration ambiguity by ensuring that TDD-specific timing requirements are met, thereby eliminating unnecessary retransmissions while keeping the overall configuration manageable through structured parameter separation.

The patent enhances the feedback mechanism by introducing explicit timing indication fields in the downlink control information that clearly specify the intended HARQ-ACK transmission timing. This feedback refinement ensures that both the base station and user equipment have a common understanding of the timing relationship, preventing misinterpretation during reconfiguration events and reducing spurious retransmissions caused by timing confusion.

The patent applies segmentation by assigning distinct timing indication fields and parameter sets to each TDD SCell based on its specific UL-DL configuration. This allows the system to simultaneously support multiple TDD SCells with different configurations (e.g., different numbers of downlink subframes) without causing mapping ambiguity. Each SCell's HARQ-ACK timing is independently determined, preserving spectrum utilization efficiency while maintaining clear information mapping.

The patent implements local quality by allowing each TDD SCell to have customized HARQ timing parameters tailored to its specific UL-DL configuration. Instead of applying a uniform timing rule across all SCells, the system adjusts timing parameters locally for each carrier based on its operational characteristics. This ensures that HARQ-ACK mapping remains unambiguous for each individual SCell while supporting diverse spectrum utilization patterns across multiple carriers.