D2D UE Frame Structure Configuration for TDD Interference Avoidance
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Solution Overview
Problem
In the LTE D2D TDD system, UEs face interference and resource allocation challenges, particularly in eIMTA scenarios where dynamic frame structure adjustment is needed, and determining suitable subframes for D2D signal transmission is difficult, especially when UEs are outside network coverage or have different frame structures.
Innovation Solution
A method for user equipment to receive or determine a configured frame structure, transmit D2D signaling to indicate frame structure, and select suitable subframes for D2D communication, allowing dynamic resource allocation and interference avoidance by using physical layer signaling and SIB, ensuring compatibility with existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UEs use different frame structures in eIMTA scenarios, then adaptability to different network conditions is improved, but interference between UEs with different frame structures increases
Solution Approach 1:
The patent applies local quality by allowing different UEs to have different frame structures (TDD UL/DL frame structures #0-6) adapted to their local network conditions and coverage scenarios. Each UE can independently select or be configured with a frame structure that matches its specific environment, whether in-coverage or out-of-coverage, while the D2D resource allocation mechanism ensures local coordination to minimize interference between these diverse configurations.
2Adaptability or versatility
If UEs outside network coverage determine frame structure by themselves, then autonomy and adaptability are improved, but difficulty in determining suitable subframes for D2D transmission increases
Solution Approach 1:
The patent implements dynamics by enabling UEs outside network coverage to dynamically determine their own frame structures based on local conditions rather than relying on static network configuration. The UE can select from multiple TDD UL/DL frame structures (#0-6) and adaptively identify suitable D2D transmission subframes within the determined frame structure, allowing the system to respond flexibly to changing environmental conditions while maintaining proper timing relationships for D2D communication.
3Object-affected harmful factors
If uplink subframes are used for D2D communication to avoid downlink interference, then interference avoidance is improved, but resource allocation flexibility deteriorates
Solution Approach 1:
The patent applies dynamics by allowing the D2D resource allocation to be flexible within the uplink subframe constraint. While D2D communication is restricted to uplink subframes to avoid downlink interference, the system dynamically selects which specific uplink subframes are suitable for D2D transmission based on the determined frame structure and local conditions. This dynamic selection process maintains interference avoidance while providing sufficient flexibility for resource allocation across different scenarios and frame structures.
Data Source
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AI summary
Proposed are a method and device for communication in a D2D UE of a TDD system. In one embodiment, a UE receiving a downlink signalling in step 1 to obtain a first configured frame structure, or voluntarily determining the first configured frame structure, and sending a first D2D signalling to indicate the first configured frame structure in step 2, wherein the first configured frame structure indicates the uplink and downlink direction of each subframe in a radio frame. By means of the technical solution provided in the present invention, the problem that a UE configured with different frame structures in an eIMTA scenario is interfered with by a downlink signal when performing D2D communications is solved.