Terminal NACK Feedback Cyclic Shift Mapping for MBS
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication systems face challenges in efficiently transmitting Negative Acknowledgment (NACK) feedback for combinations of transport blocks (TBs) in Multicast and Broadcast Services (MBS) using the Hybrid Automatic Repeat Request (HARQ) mechanism, particularly in scenarios where multiple TBs are transmitted to a single multicast group.
Innovation Solution
The proposed solution involves a terminal device determining the need to transmit a NACK feedback for at least one TB, selecting a cyclic shift value from a mapping table associated with the TBs, generating a sequence based on this value, and transmitting the NACK feedback using this sequence. The network device then decodes the sequence to identify the specific TB(s) for which the NACK feedback is intended.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is transmitted for each transport block in multicast groups, then transmission reliability is improved, but feedback complexity and overhead increase
Solution Approach 1:
The patent combines feedback for multiple transport blocks into a single NACK transmission. When any TB in a multicast group is not successfully received, the terminal device generates one NACK signal that represents feedback for the failed TB(s), rather than transmitting separate feedback signals for each TB. This merging approach maintains reliability by ensuring feedback is provided while reducing feedback complexity and overhead.
Solution Approach 2:
The NACK signal serves multiple functions simultaneously: it indicates which TB(s) failed to be received, triggers retransmission at the network device, and does so using a unified feedback mechanism that works across multiple TBs in a multicast group. This multi-functionality reduces the need for separate feedback mechanisms for each TB.
2Measurement precision
If separate feedback is transmitted for each transport block combination, then feedback precision is improved, but signaling overhead increases
Solution Approach 1:
The patent merges feedback for different TB combinations into a single NACK signal. Instead of transmitting separate feedback signals for each possible TB combination (which would create exponential signaling overhead), the system uses one unified NACK transmission that conveys which TB(s) need retransmission, thereby maintaining feedback precision while dramatically reducing signaling overhead.
3Measurement precision
If cyclic shift values are mapped to TB combinations, then feedback identification accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent uses cyclic shift values as parameters to encode TB combination information. By mapping different TB combinations to specific cyclic shift values, the system enables the network device to identify which TB(s) failed based on the received NACK signal's cyclic shift property. This parameter-based approach improves feedback identification accuracy while keeping processing relatively simple through predefined mapping tables.
Solution Approach 2:
The cyclic shift value acts as an intermediary that carries information about TB combinations without requiring direct transmission of the combination data itself. The mapping table serves as a lookup intermediary, allowing both terminal and network devices to translate between cyclic shift values and TB combinations efficiently, thereby improving identification accuracy while managing processing complexity through standardized mappings.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices, and computer readable medium for communication. According to some embodiments, a method comprises determining, at a terminal device, that a negative acknowledgment (NACK) feedback is to be transmitted for at least one of a set of transport blocks (TBs) transmitted from a network device; selecting, from a mapping table associated with the set of TBs, a cyclic shift value mapped to a combination of the at least one TB; generating a sequence at least based on the selected cyclic shift value; and transmitting, to the network device, the NACK feedback for the at least one TB using the generated sequence.