MBMS Retransmission via Intermediary Network Device
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Solution Overview
Problem
Current multimedia broadcast multicast service (MBMS) transmission in communication technologies restricts spectral efficiency due to modulation and coding rate limitations by edge terminal devices, as all terminals in a cell receive the same data, leading to inefficient resource utilization.
Innovation Solution
A communication method where a terminal device requests retransmission of failed data packets from a second network device, allowing the first network device to lower coverage requirements and use more efficient multicast transmission schemes and coding rates, thereby improving spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all terminals in a cell receive the same MBMS data with modulation scheme and coding rate restricted by edge terminal devices, then coverage requirement is met, but spectral efficiency is low
Solution Approach 1:
The patent segments the transmission function into two parts: the first network device performs multicast transmission to most terminals, while the second network device provides unicast retransmission specifically for edge terminals that fail to receive packets successfully. This segmentation allows the system to use efficient modulation schemes for multicast while providing targeted support for coverage-edge terminals.
Solution Approach 2:
The second network device acts as an intermediary between the first network device and edge terminal devices. It receives retransmission requests from terminals and retrieves original data packets from the first network device, then forwards them to the requesting terminals via unicast. This intermediary mechanism resolves the conflict between using efficient multicast schemes and meeting coverage requirements.
2Productivity
If first network device uses efficient multicast transmission modulation scheme and coding rate, then spectral efficiency is improved, but edge terminal devices may not receive data packets successfully
Solution Approach 1:
The system performs preliminary multicast transmission using efficient modulation schemes and coding rates to most terminals. Before finalizing the transmission, the system allows edge terminals to request retransmission of any missed packets through the second network device, ensuring successful reception without compromising the efficiency of the initial transmission.
Solution Approach 2:
The patent changes the transmission parameters dynamically: the first network device uses efficient modulation schemes and high coding rates for multicast transmission to improve spectral efficiency, while the second network device uses reliable unicast transmission with appropriate parameters for retransmitting packets to edge terminals that need them.
3Productivity
If first network device lowers coverage requirement, then it can use more efficient modulation scheme and coding rate, but edge terminal devices will not receive data packets effectively
Solution Approach 1:
The patent segments the terminal group into two categories: terminals that receive multicast data successfully and edge terminals that may fail to receive packets. The first network device lowers coverage requirements for the majority, while the second network device provides targeted unicast retransmission to edge terminals, ensuring overall reception effectiveness while improving spectral efficiency.
Data Source
AI summary
Examples in this application provide a communication method, apparatus, device, and system, and a storage medium. One example method includes determining, by a terminal device, that the first data packet of the target service sent by the first network device is not successfully received, sending, by the terminal device, a first message to a second network device, to request to retransmit the first data packet, and receiving, by the terminal device, the first data packet from the second network device.