D2D Broadcast Resource Scheduling for Off-Network Reliability
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Solution Overview
Problem
Current D2D communication systems face challenges in improving broadcast reliability and system throughput, especially in scenarios without network coverage, due to mobility and lack of feedback mechanisms, which affects the reception of important messages in public safety scenarios.
Innovation Solution
The method involves acquiring classification information of service information and corresponding control information to indicate resource scheduling during transmission and retransmission, and transmitting service and control information in a broadcast manner according to a preset rule, allowing for improved resource allocation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lower code rate is adopted to improve broadcast reliability, then reception reliability is improved, but system throughput deteriorates
Solution Approach 1:
The service information is segmented into multiple transmission blocks, each with its own control information. This allows selective retransmission of only failed segments rather than retransmitting all data, improving reliability without proportionally reducing throughput.
Solution Approach 2:
Control information including resource scheduling for retransmission is prepared in advance along with the initial transmission. This preliminary action enables receiving devices to know exactly when and where to expect retransmissions, improving reliability while maintaining efficient resource utilization and throughput.
2Reliability
If transmission power is increased to improve reception in mobile environments, then broadcast reliability is improved, but energy consumption increases
Solution Approach 1:
Instead of continuously transmitting at high power, the system transmits control information and service information selectively. Retransmissions are performed only for specific resource allocations when needed, providing improved reliability without the continuous energy expenditure of high-power transmission.
Solution Approach 2:
The system uses pre-configured control information to enable receiving devices to autonomously manage their reception and feedback processes. This self-service approach improves reliability through coordinated retransmissions without requiring continuous high-power broadcasting to all devices.
3Productivity
If retransmission is implemented to improve spectral efficiency, then system throughput is improved, but device complexity increases due to feedback mechanisms
Solution Approach 1:
The feedback mechanism is extracted and integrated directly into the control information that is already being transmitted. By embedding resource scheduling and retransmission indicators in the control information, the patent avoids adding separate feedback channels and processing complexity while still achieving improved spectral efficiency through targeted retransmissions.
4Reliability
If a lower code rate is used to ensure reception in severe environments, then broadcast reliability is improved, but transmission efficiency deteriorates
Solution Approach 1:
Different code rates and transmission parameters are applied locally to different service information blocks based on their specific requirements. Critical information can use lower code rates for reliability, while less critical information uses higher code rates for efficiency, resolving the contradiction between reliability and transmission efficiency.
Solution Approach 2:
The system dynamically changes transmission parameters including code rate, resource allocation, and retransmission timing based on channel conditions and service requirements. This allows the system to optimize for reliability when needed and for efficiency when conditions permit, resolving the contradiction between broadcast reliability and transmission efficiency.
Data Source
AI summary
Provided are methods and devices for transmitting or receiving Device-to-Device (D2D) broadcast information, and a transmission system. The method for transmitting the D2D broadcast information includes that: classification information of service information to be transmitted is acquired; control information corresponding to the classification information is acquired, wherein the control information is used for indicating resource scheduling information used during transmission and/or retransmission of the service information; and the service information and the control information are transmitted in a broadcast manner according to a preset rule.