D2D User Terminal Resource Segmentation for Collision Avoidance
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Solution Overview
Problem
In mobile communication systems supporting Device-to-Device (D2D) proximity services, there is a likelihood of control information collision between user terminals when they randomly select time-frequency resources, leading to potential failure in receiving control information.
Innovation Solution
A mobile communication system that includes user terminals configured to transmit notification information and control information indicating the location of data resources, with mechanisms to prioritize emergency information and manage resource allocation to avoid collisions, such as using dedicated time-frequency resources for emergency transmissions and selective SA resource transmission based on notification requests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If user terminals randomly select time-frequency resources for transmitting control information, then the ease of operation is improved, but control information collision occurs reducing reliability
Solution Approach 1:
The time-frequency resource space is segmented into different types of resources: dedicated resources for emergency notification information and shared resources for other control information. This segmentation allows emergency transmissions to have guaranteed reliability while other transmissions can use random selection, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
Different quality levels are assigned to different resource types. Emergency notification resources provide high reliability with priority transmission, while general control information resources allow random selection. This local differentiation of quality characteristics enables simultaneous optimization for both reliability and ease of operation in different contexts.
2Reliability
If dedicated time-frequency resources are allocated for emergency notification information, then reliability of emergency communication is improved, but device complexity increases
Solution Approach 1:
The critical function of emergency notification is extracted from the general control information transmission mechanism. By separating emergency notifications into dedicated resources with guaranteed transmission rights, the system achieves high reliability for emergency communication without requiring complex resource management algorithms for all transmissions.
Solution Approach 2:
Instead of implementing complex resource management for all control information, the system applies simple priority-based transmission only to emergency notifications (excessive action for critical cases), while allowing random selection for non-emergency transmissions. This partial application of strict resource management achieves the required reliability without excessive overall complexity.
Data Source
AI summary
A mobile communication system according to the present invention is a mobile communication system that supports a D2D (Device-to-Device) proximity service in which direct communication not passing through a network is enabled, and comprises: a first user terminal configured to transmit notification information for notifying presence of first D2D communication data scheduled to be directly transmitted to another user terminal. The first user terminal is further configured to transmit, after transmitting the notification information, control information indicating a location of a data resource used for transmitting the first D2D communication data.