TDD Configuration for D2D Discovery in Cellular Networks
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Solution Overview
Problem
Current device-to-device (D2D) communication systems face challenges in efficiently configuring time-division duplexing (TDD) for D2D open discovery, particularly in ensuring D2D discovery signals are transmitted on uplink subframes during TDD frame configuration changes, which is crucial for minimizing interference and ensuring successful proximity-based services.
Innovation Solution
A method and system that select and indicate a TDD frame configuration to devices, determining a D2D discovery configuration to allocate transmission resources for D2D discovery signals during specific intervals, ensuring these signals are transmitted on uplink subframes, even during TDD frame reconfigurations, using various schemes such as reserving subframe 2 or employing special subframes like UpPTS for D2D discovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If D2D discovery signals are transmitted on uplink subframes during TDD frame configuration changes, then interference with cellular communications is minimized, but device complexity increases due to the need for dynamic configuration management
Solution Approach 1:
The network component pre-determines and signals the TDD frame configuration to devices before D2D discovery signal transmission begins. This preliminary configuration assignment ensures devices know in advance which subframes are designated for uplink D2D discovery, eliminating the need for complex real-time configuration management at the device level while ensuring signals are transmitted on appropriate uplink subframes
Solution Approach 2:
The network component acts as an intermediary that manages the TDD frame configuration and translates it into device-specific D2D discovery configurations. This intermediary role centralizes the complexity of dynamic configuration management at the network level, allowing devices to simply follow the configured parameters without implementing complex configuration management themselves
2Adaptability or versatility
If TDD frame configuration is changed frequently to adapt to varying traffic demands, then system adaptability improves, but reliability of D2D discovery decreases due to potential misalignment of discovery signals with uplink subframes
Solution Approach 1:
The network component continuously monitors TDD traffic demands and provides feedback by updating the TDD frame configuration and corresponding D2D discovery configurations. This feedback mechanism ensures that when TDD frame configuration changes occur, the D2D discovery configuration is simultaneously updated to maintain alignment with uplink subframes, preserving reliability while allowing frequent configuration changes for adaptability
Solution Approach 2:
The system implements dynamic configuration where both the TDD frame configuration and D2D discovery configuration can change in response to varying traffic demands. The network component dynamically adjusts the D2D discovery configuration parameters (such as discovery time intervals and subframe assignments) to match the current TDD frame configuration, ensuring that discovery signals always align with uplink subframes regardless of how frequently the configuration changes
3Productivity
If D2D discovery configuration is determined according to each selected TDD frame configuration, then transmission resources are optimized, but network signaling overhead increases
Solution Approach 1:
The network component determines D2D discovery configuration parameters (such as discovery time interval, subframe offset, and resource allocation) based on the selected TDD frame configuration parameters. By changing the configuration parameters in a coordinated manner - where D2D discovery parameters are derived from or linked to the TDD frame parameters - the system optimizes transmission resources for each TDD configuration while reducing signaling overhead through parameter correlation rather than independent configuration management
Data Source
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AI summary
Embodiments are provided to support device-to-device (D2D) communications in a time- division duplexing (TDD) communications system, and ensure that D2D discovery signals are transmitted by user devices on an uplink subframe when there is a TDD frame configuration change. In an embodiment, a user device receives form the network a TDD frame configuration selected from a set of available TDD frame configurations according to the TDD configuration. The device further receives a D2D discovery configuration for a discovery time interval. The user device then allocates a transmission resource a D2D discovery signal within the discovery time interval according to the D2D discovery configuration. The user device is also configured to receive from another device a second D2D discovery signal during the discovery time interval in accordance with the TDD configuration and the D2D discovery configuration.