Dynamic HARQ Feedback for Multicast and Broadcast Services
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing Hybrid Automatic Repeat Request (HARQ) feedback for multicast and broadcast services, particularly in 4G and 5G networks, due to the lack of clear mechanisms for enabling or disabling HARQ feedback operations, which affects data transmission reliability and efficiency.
Innovation Solution
A method for a base station to transmit RRC messages with parameters indicating either enabled or disabled HARQ feedback operations, along with group common DCI for scheduling transport blocks and receiving corresponding feedback, allowing flexible HARQ feedback management for multicast and broadcast services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is enabled for multicast and broadcast services, then data transmission reliability is improved, but system complexity and resource overhead increase
Solution Approach 1:
The patent implements dynamic HARQ feedback management by introducing a feedback enablement indicator in DCI messages. This allows the base station to flexibly enable or disable HARQ feedback on a per-transmission basis, rather than using a fixed configuration. The dynamic switching mechanism resolves the contradiction by adapting the feedback mechanism to actual transmission needs, maintaining reliability when necessary while reducing complexity when not needed.
Solution Approach 2:
The patent changes the operational parameters of HARQ feedback by introducing configurable indicators in RRC messages and DCI. These parameters control whether HARQ feedback is enabled or disabled for specific multicast and broadcast transmissions. By making these parameters configurable rather than fixed, the system can optimize between reliability and complexity based on service requirements and channel conditions.
2Reliability
If HARQ feedback is enabled for all multicast transmissions, then transmission reliability improves, but uplink resource consumption increases
Solution Approach 1:
The patent segments the HARQ feedback mechanism by applying it selectively to different multicast transmissions rather than uniformly to all transmissions. Through the feedback enablement indicator in DCI and configurable parameters in RRC messages, the system divides multicast transmissions into those requiring feedback and those that do not, based on service type, channel conditions, and reliability requirements. This segmentation reduces unnecessary uplink resource consumption while maintaining reliability where needed.
Solution Approach 2:
The patent implements partial HARQ feedback by enabling it only for specific transmissions rather than all transmissions. The feedback enablement indicator allows the base station to apply HARQ feedback partially - only when the indicator is set - rather than excessively applying it to every multicast transmission. This partial action optimizes the balance between reliability improvement and resource consumption.
3Device complexity
If HARQ feedback mechanisms are simplified for multicast services, then system complexity reduces, but feedback accuracy and reliability deteriorate
Solution Approach 1:
The patent creates a universal HARQ feedback management mechanism that serves multiple functions through the feedback enablement indicator and configurable parameters. This single mechanism can disable feedback completely, enable feedback for all transmissions, or enable feedback selectively based on transmission type, channel conditions, or service requirements. The multi-functionality resolves the contradiction by providing accurate feedback control without requiring separate complex mechanisms for different scenarios.
Data Source
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AI summary
A wireless device receives messages comprising parameters of a multicast and broadcast service (MBS) session. The parameters indicate hybrid automatic repeat request (HARQ) feedback operations. The HARQ feedback operations comprise a first feedback operation with HARQ feedback being enabled; and a second feedback operation with the HARQ feedback being disabled. A downlink control information (DCI) indicates one of the first or the second feedback operation. The wireless device receives a first DCI scheduling a transport block (TB) of the MBS session; and indicating the first feedback operation. The wireless device transmits, based on the first DCI indicating the first feedback operation, a first HARQ feedback for the TB .