Dynamic TTI Adjustment in E-DCH HARQ Processes

The patent applies preliminary action by determining the TTI change timing in advance based on HARQ process status. The system calculates the appropriate timing for TTI changes considering the HARQ round trip time, ensuring that TTI configuration changes occur at optimal moments that minimize disruption to ongoing HARQ processes. This advance planning allows the system to maintain HARQ integrity while enabling TTI flexibility.

The patent implements dynamics by making the TTI configuration changeable during system operation rather than fixed. The TTI can be dynamically adjusted based on channel conditions and traffic requirements, with the system adapting the TTI length (e.g., switching between 2ms and 10ms) while coordinating these changes with HARQ process states to maintain reliability during the transition.

The patent applies feedback by continuously monitoring HARQ process status (ACK/NACK states, retransmission counts, process identifiers) and using this information to determine the optimal timing for TTI changes. The system receives feedback from the HARQ layer about ongoing processes and adjusts TTI configuration timing accordingly, ensuring that TTI changes occur only when they will not cause data loss from incomplete HARQ operations.

The system performs self-service by automatically determining the appropriate TTI change timing based on its own internal HARQ process state without requiring external intervention. The UE and Node B independently monitor their respective HARQ processes and autonomously decide when TTI changes can be safely made, enabling fast adaptation while preventing data loss through self-coordinated timing decisions.