Broadcast Communication Feedback Mechanism for Spectral Efficiency
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Solution Overview
Problem
Current broadcast and multicast communication modes in wireless systems face challenges with low spectral efficiency due to the lack of a feedback mechanism, leading to the need for robust modulation and coding schemes that reduce system performance.
Innovation Solution
A communication method is introduced that includes a feedback and retransmission mechanism, where terminal devices send acknowledgment information to access network devices, allowing the system to determine retransmission areas and adjust resource allocation, thereby improving spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicasting is used to transmit data to multiple terminal devices, then network device load is reduced and service coverage is expanded, but spectral efficiency deteriorates due to the lack of error correction mechanism requiring robust modulation and coding schemes
Solution Approach 1:
The patent introduces a feedback mechanism where terminal devices send acknowledgment information (ACK/NACK) to the network device. The network device determines retransmission areas based on this feedback, enabling adaptive retransmission only where needed. This resolves the contradiction by maintaining multicast efficiency while providing targeted error correction to improve spectral efficiency.
Solution Approach 2:
The patent implements localized retransmission by determining specific retransmission areas based on feedback from terminal devices. Instead of retransmitting to all terminal devices, the network device identifies and retransmits only to areas where packet loss occurred. This maintains the efficiency of multicasting while providing robust error correction only where necessary, improving spectral efficiency.
2Adaptability or versatility
If unicast is used to provide personalized services to terminal devices, then service personalization is improved, but network device load increases when there are large quantities of terminal devices with heavy access traffic
Solution Approach 1:
The patent segments the service delivery mechanism into two parts: initial multicast transmission for common data to multiple terminal devices, and targeted unicast retransmission for personalized error correction. This segmentation allows the network device to efficiently serve multiple devices simultaneously while providing personalized services only where needed, reducing overall network device load.
3Reliability
If robust modulation and coding schemes are used in multicasting to ensure communication quality, then reliability is improved, but spectral efficiency deteriorates
Solution Approach 1:
The patent applies partial error correction by implementing feedback-based retransmission only for terminal devices or areas that experience packet loss. Instead of using robust modulation and coding schemes for all transmissions, the system uses simpler schemes initially and applies additional error correction only partially where needed. This maintains communication quality for affected devices while improving overall spectral efficiency.
Data Source
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AI summary
Embodiments of this application provide a communication method and an apparatus, relate to the communication field, and in particular, are applicable to a broadcast system. The method includes: A terminal device receives a first downlink channel from an access network device, where the first downlink channel is scrambled by using a first identifier and is used to carry first data. The terminal device receives a second downlink channel from the access network device, where the second downlink channel is scrambled by using a second identifier and is used to retransmit the first data. The first identifier and the second identifier are identifiers configured by the access network device. This method can implement a feedback retransmission mechanism combining broadcast initial transmission and partial retransmission, to further improve spectral efficiency of a communication system.