HARQ Feedback in Unlicensed Spectrum via Dynamic LBT

The patent applies dynamics by making the LBT procedure optional rather than fixed. The wireless device dynamically decides whether to perform LBT based on the gap size between downlink and uplink transmissions. When the gap is below a threshold, LBT is skipped; when above, LBT is performed. This dynamic adaptation resolves the contradiction by allowing reliable feedback transmission without unnecessary LBT-induced uncertainty.

The patent changes the parameter of LBT execution based on the time gap condition. By using the gap size as a decision parameter, the system transitions from a static LBT requirement to a conditional one. This parameter-based approach allows the system to maintain reliability by skipping LBT in tight scheduling scenarios while complying with regulations in more relaxed scenarios.

The patent introduces dynamic timing adjustment by allowing the wireless device to transmit feedback earlier than predefined times when the gap condition is met. Instead of rigidly following predefined feedback occasions, the device can adaptively transmit feedback as soon as the gap threshold is satisfied, thereby maintaining simplicity while improving reliability through flexible timing.

The patent applies preliminary action by enabling the wireless device to perform feedback transmission in advance of the predefined feedback time when conditions allow. By transmitting feedback earlier when the gap is small, the system ensures reliable delivery before LBT failures could occur at later predefined occasions, thus resolving the reliability issue while maintaining operational simplicity.

The patent applies partial action by performing LBT only when necessary - specifically when the gap between downlink and uplink transmissions exceeds the threshold. In cases where the gap is already small, LBT is omitted entirely. This partial application of LBT maintains channel access reliability where needed while avoiding the throughput degradation caused by unnecessary LBT procedures and retransmissions.

The patent changes the LBT execution parameter based on the gap condition. By using the time gap as a conditional parameter, the system avoids fixed LBT execution that would harm throughput. Instead, LBT is dynamically enabled or disabled based on whether the gap exceeds the threshold, thus maintaining reliability when needed while preserving throughput in tight scheduling scenarios.

The patent changes the codebook size parameter dynamically based on LBT success outcomes. When LBT succeeds, a larger codebook can be used for comprehensive feedback; when LBT fails or is skipped, a smaller codebook is used. This parameter adaptation improves feedback efficiency by matching codebook size to actual transmission conditions while managing complexity through clear conditional logic.

The patent applies feedback by using the LBT success outcome to determine the appropriate codebook size for subsequent feedback transmission. The system continuously adapts the codebook parameter based on real-time LBT results, creating a feedback loop that optimizes efficiency. This dynamic feedback mechanism improves productivity while keeping complexity manageable through rule-based adaptation.