MBS Downlink Retransmission with HARQ Data Combining
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Solution Overview
Problem
The existing LTE technology does not support Hybrid Automatic Repeat Request (HARQ) transmission for multicast and broadcast services (MBS), leading to decreased decoding success rates and increased packet loss due to repeated data transmissions without combination or decoding.
Innovation Solution
Implementing a HARQ process for MBS that allows combining and decoding repeated data transmissions, improving reliability by using specific HARQ processes for MBS, and configuring HARQ feedback based on reception conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If MBS uses one-time sending without HARQ transmission, then the system complexity is reduced, but the decoding success rate decreases and packet loss rate increases
Solution Approach 1:
The patent segments the MBS transmission process into multiple HARQ processes (first HARQ process for initial transmission, second HARQ process for retransmission), allowing independent handling of transmission and retransmission with different configurations. This segmentation enables the system to maintain simplicity for initial transmission while adding reliability through structured retransmission mechanisms.
Solution Approach 2:
The patent introduces dynamic switching between different HARQ processes based on transmission conditions. The network device can dynamically select whether to use the first HARQ process (without feedback) or second HARQ process (with feedback) based on channel conditions and service requirements, making the system adaptable while maintaining overall simplicity.
2Reliability
If MBS repeatedly sends data without HARQ combination, then the coverage and reliability are improved, but the packet loss rate increases due to inability to combine data
Solution Approach 1:
The patent introduces HARQ feedback mechanisms in the second HARQ process where the terminal sends feedback information (ACK/NACK) to the network device. This feedback enables the network to determine whether retransmission is needed, reducing unnecessary transmissions and packet loss while maintaining reliability through targeted retransmissions based on actual decoding outcomes.
Solution Approach 2:
The patent configures the terminal with multiple HARQ processes in advance, with the second HARQ process pre-configured for retransmission and data combination. This preliminary configuration allows the terminal to immediately combine retransmitted data with previously received data without additional setup delay, reducing packet loss through pre-established combination capabilities.
3Reliability
If HARQ feedback is always sent for MBS retransmission, then the decoding success rate is improved, but the feedback overhead and system complexity increase
Solution Approach 1:
The patent divides HARQ feedback requirements into two segments: the first HARQ process (initial transmission) operates without feedback to minimize overhead, while the second HARQ process (retransmission) uses feedback to improve decoding success rate. This segmentation allows feedback to be applied only where necessary, balancing reliability improvement with overhead control.
Solution Approach 2:
The patent enables dynamic selection of HARQ processes based on transmission stage and channel conditions. The network device can dynamically determine whether to activate feedback mechanisms in the second HARQ process based on actual transmission outcomes, making the feedback overhead adaptive rather than fixed, thus reducing overall system complexity while maintaining reliability.
Data Source
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AI summary
Embodiments of the present invention provide a downlink data receiving method, a downlink data sending method, and a device. The method includes: obtaining a HARQ process of an MBS; and receiving downlink data of the MBS according to the HARQ process. In the embodiments of the present invention, a specific MBS can be sent and retransmitted through a corresponding HARQ process, so that a terminal can combine and decode data repeatedly sent by a network side for a plurality of times, thereby improving a decoding success rate and thus improving sending reliability of the specific MBS.