D2D Resource Allocation in Dynamic TDD Configuration
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Solution Overview
Problem
In LTE systems, terminal devices face challenges in performing device-to-device (D2D) communication under Time Division Duplex (TDD) environments, particularly when the uplink/downlink configuration dynamically changes, leading to potential disruptions in cellular communication quality and resource allocation inefficiencies.
Innovation Solution
A mechanism where the base station dynamically changes the UL/DL configuration of the TDD carrier and notifies terminal devices of appropriate radio resources for D2D communication, ensuring continuous D2D communication in uplink subframes by allocating specific radio resources, thereby minimizing disruptions to TDD radio communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If periodic radio resources are allocated for D2D communication in uplink subframes, then D2D communication can be performed in TDD environment, but when UL/DL configuration dynamically changes, the allocated uplink subframe may become downlink subframe or special subframe, causing D2D communication to non-compliant subframes
Solution Approach 1:
The base station performs preliminary action by notifying the terminal device of the UL/DL configuration before D2D communication occurs. This allows the terminal device to advance identify which subframes are uplink subframes and allocate D2D resources only in compliant subframes, preventing non-compliant communication before it happens.
Solution Approach 2:
The base station provides feedback about the UL/DL configuration to the terminal device, enabling the terminal device to adjust its D2D resource allocation based on the actual TDD configuration state. This feedback mechanism ensures continuous compliance with cellular communication standards while maintaining D2D communication functionality.
2Productivity
If uplink subframe is allocated for D2D communication, then D2D communication resources are available, but TDD radio communication quality may be degraded due to dynamic configuration changes
Solution Approach 1:
The base station notifies the terminal device of the UL/DL configuration in advance, allowing the terminal device to pre-determine appropriate D2D resources based on the current TDD configuration. This preliminary action ensures that D2D communication only occurs in valid uplink subframes, preventing interference with downlink communication and maintaining TDD radio communication quality.
Solution Approach 2:
The system dynamically adapts D2D resource allocation to match the current UL/DL configuration state. When the TDD configuration changes, the terminal device re-evaluates and adjusts D2D resources based on the new configuration, ensuring continuous compliance and preventing degradation of TDD radio communication quality while maintaining D2D productivity.
Data Source
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AI summary
A device configured to set an uplink/downlink configuration of a carrier, and notify of a radio resource for device-to-device communication for the uplink/downlink configuration. The radio resource is a radio resource of at least one uplink subframe of the uplink/downlink configuration. The device is further configured to change the uplink/downlink configuration from one configuration among multiple configurations to another configuration among the multiple configurations, and to notify of the radio resource for device-to-device communication for the other configuration, wherein the radio resource appropriate for the other configuration is a radio resource of at least one uplink subframe of the other configuration.