HARQ-ACK Sequence Selection for Dynamic TDD Uplink Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The configurable timing of hybrid automatic repeat request (HARQ) acknowledgment (ACK)/negative ACK (NACK) in new radio time-division duplexing (NR-TDD) systems leads to latency due to semi-static uplink slot configurations, and dynamic TDD with subband non-overlapping full duplex (SBFD) schemes increase uplink transmission opportunities, necessitating improved HARQ-ACK timing mechanisms.
Innovation Solution
A wireless transmit/receive unit (WTRU) determines a set of sequences for HARQ-ACK based on configuration information, including a first sequence, a WTRU-specific root index or cyclic shift, and uplink subbands within SBFD time units, selecting a second sequence based on PDCCH monitoring occasions and a counter value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If semi-static uplink slot configurations are used for HARQ-ACK timing, then uplink transmission structure is simplified, but transmission latency increases
Solution Approach 1:
The patent applies dynamics by transitioning from semi-static to dynamic TDD configurations, allowing uplink slots to be flexibly assigned based on real-time traffic conditions. The base station dynamically determines uplink slot assignments and notifies WTRUs, enabling adaptive HARQ-ACK timing that reduces latency while maintaining manageable complexity through standardized dynamic signaling procedures.
Solution Approach 2:
The patent changes the timing parameter K1 dynamically based on traffic conditions and slot configurations. Instead of fixed HARQ-ACK timing offsets, the system adjusts K1 values adaptively according to dynamic TDD patterns, allowing optimization of latency performance while keeping the overall transmission structure relatively simple through parameter adaptation rather than structural redesign.
2Productivity
If dynamic TDD with SBFD schemes is implemented, then uplink transmission opportunities increase, but system complexity increases
Solution Approach 1:
The patent segments the frequency band into subbands for SBFD operation, allowing simultaneous uplink and downlink transmissions in different frequency portions. This segmentation enables increased uplink opportunities by utilizing previously downlink-only frequency resources, while managing complexity through structured subband allocation and interference coordination mechanisms.
Solution Approach 2:
The patent introduces frequency domain dimensioning by implementing SBFD, where uplink transmissions occur in specific subbands within downlink time units. This adds a frequency dimension to the traditional time-division approach, increasing uplink opportunities without proportionally increasing time-domain complexity through structured multi-dimensional resource allocation.
3Loss of time
If sequence selection is based on PDCCH monitoring occasions, then HARQ-ACK timing is optimized, but processing complexity increases
Solution Approach 1:
The patent implements self-service by enabling WTRUs to autonomously determine appropriate sequences for HARQ-ACK transmission based on their own PDCCH monitoring occasion counts and configured parameters. Each WTRU independently selects sequences from configured sets based on local counter values and received configurations, optimizing timing without requiring complex centralized scheduling decisions.
Solution Approach 2:
The patent applies preliminary action by pre-configuring multiple sequence sets and associated parameters before actual HARQ-ACK transmission. WTRUs are provided with predetermined sequence options and selection criteria in advance, allowing them to quickly select appropriate sequences based on real-time monitoring occasion counts without performing complex real-time sequence generation, thus optimizing timing while limiting processing complexity.
Data Source
AI summary
A wireless transmit/receive unit (WTRU) may include a transceiver and a processor. The WTRU may be configured to receive one or more downlink signals. The WTRU may be configured to receive configuration information indicating time and frequency resources for transmission of hybrid automatic repeat request (HARQ) acknowledgement (ACK). The configuration information may indicate a first sequence. The WTRU may be configured to determine a set of sequences to be used in response to the receipt of the one or more downlink signals. The set of sequences may be determined based on the indicated first sequence. The WTRU may be configured to send a second sequence from the set of sequences in the time and frequency resources to indicate HARQ-ACK. The second sequence may be selected based on a number of physical downlink control channel (PDCCH) monitoring occasions associated with the indicated HARQ-ACK.