HARQ-ACK Codebook Handling During Downlink BWP Switching
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting uplink control information due to resource shortages and high-speed service demands, particularly in 5G networks with dynamic TDD and mmWave bands, where beamforming and advanced connectivity technologies are required for IoT applications.
Innovation Solution
A user equipment in a wireless communication system adjusts its downlink bandwidth part (BWP) based on a physical downlink control channel (PDCCH) indication, excluding certain physical downlink shared channels (PDSCH) from the candidate set and transmitting a semi-static HARQ-ACK codebook, considering factors like symbol allocation, uplink symbols, and processing times to optimize uplink control information transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic TDD is used to vary the number of OFDM symbols according to data traffic directions, then spectral efficiency is improved, but the complexity of downlink control information increases
Solution Approach 1:
The patent segments the HARQ-ACK codebook into two distinct types: semi-static codebook (for configured grant type 1 and PDSCH) and dynamic codebook (for PUSCH). This segmentation allows the system to manage the complexity of dynamic TDD by handling different traffic scenarios through separate codebook mechanisms, thereby maintaining spectral efficiency while reducing control information processing burden.
Solution Approach 2:
The patent introduces dynamic adaptation mechanisms where the UE determines the HARQ-ACK codebook type based on real-time conditions (configured grant type, PDSCH reception status). The system dynamically switches between semi-static and dynamic codebooks depending on the actual traffic direction and channel conditions, enabling flexible adaptation to varying spectral requirements without overwhelming complexity.
2Length of stationary object
If beamforming and massive MIMO are implemented to alleviate path loss in mmWave band, then transmission distance is improved, but device complexity increases
Solution Approach 1:
The patent extracts and prioritizes HARQ-ACK feedback for critical PDSCH receptions, separating them from less critical feedback. By identifying and handling only the essential feedback elements (semi-static codebook for configured grant type 1 and PDSCH), the system reduces the feedback overhead that would otherwise compound with the complexity of beamforming and massive MIMO antenna systems.
3Speed
If uplink control information transmission is optimized for high-speed services, then data transfer rate is improved, but reliability of control information transmission deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring the semi-static HARQ-ACK codebook for configured grant type 1 transmissions before the actual data transmission occurs. This pre-establishment of feedback mechanisms ensures that control information reliability is maintained even as the system operates at high speeds, as the feedback structure is already in place and does not require real-time complex processing during high-speed data transfer.
Data Source
AI summary
A base station of a wireless communication system is disclosed. The base station of the wireless communication includes a communication module, and a processor. The processor is configured to, when receiving a physical downlink control channel (PDCCH) indicating a change of a downlink (DL) bandwidth part (BWP), change the DL BWP based on the PDCCH indicating the change of the DL BWP, and not include a physical downlink shared channel (PDSCH) scheduled by a PDCCH received before receiving the PDCCH indicating the change of the DL BWP in a PDSCH candidate set, and transmit a semi-static HARQ-ACK codebook including hybrid automatic repeat request (HARQ)-ACK information of a physical downlink shared channel (PDSCH) corresponding to the PDSCH candidate set to a base station of the wireless communication system.