Terminal HARQ Feedback Resource Indexing for MBS
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Solution Overview
Problem
In Multicast and Broadcast Services (MBS) using Hybrid Automatic Repeat Request (HARQ), the network cannot recognize the number of bits in NACK-only feedback due to varying configuration methods among User Equipment (UE), leading to the need for blind decoding.
Innovation Solution
A terminal and base station system where the terminal transmits HARQ feedback with a transmission unit and a control unit that associates a bit string of the feedback with an uplink control channel resource, using an index to indicate the correspondence and configuring an upper limit on the number of multiplexed bits by an upper layer parameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If NACK-only feedback configuration is allowed to vary for each UE, then feedback transmission flexibility is improved, but the network cannot recognize the number of bits leading to blind decoding requirement
Solution Approach 1:
An upper layer parameter is introduced as an intermediary to configure the maximum number of multiplexed bits for HARQ-ACK feedback. This parameter acts as a mediator between the flexible configuration needs and the network's recognition requirements, allowing the network to understand the feedback bit structure without requiring blind decoding.
Solution Approach 2:
The patent changes the parameter structure by introducing an upper layer parameter that explicitly defines the maximum number of multiplexed bits. This parameter change transforms the ambiguous variable-length feedback into a controlled structure where the network can recognize the bit count, resolving the blind decoding issue while preserving configuration flexibility.
2Measurement precision
If blind decoding is used to recognize feedback bits, then network recognition capability is improved, but processing time and complexity increase
Solution Approach 1:
The upper layer parameter configures the maximum number of multiplexed bits in advance, before the actual feedback transmission occurs. This preliminary configuration allows the network to pre-determine the feedback structure, eliminating the need for time-consuming blind decoding during the feedback reception phase.
3Loss of information
If the number of multiplexed bits is not limited, then feedback information completeness is improved, but resource allocation complexity increases
Solution Approach 1:
By introducing an upper layer parameter that limits the maximum number of multiplexed bits, the patent transforms the unbounded resource allocation problem into a controlled optimization problem. This parameter ensures that feedback information completeness is maintained within a manageable bit limit, simplifying resource allocation while preventing information loss.
Data Source
AI summary
A terminal includes: a transmission unit that transmits feedback of an automatic repeat request; and a control unit assuming that when a bit string of the feedback and a resource of an uplink control channel are associated with each other and only a negative acknowledgment is fed back, an index of the resource indicates a correspondence relationship between a bit string of the feedback and the resource, in which an upper limit on the number of multiplexed bits of the feedback is configured by an upper layer parameter.