D2D Communication Mode Switching via Timer-Based Resource Allocation
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Solution Overview
Problem
Current methods for device-to-device (D2D) communication in LTE systems lack efficient mechanisms for mode switching based on the type or classification of D2D communication, leading to potential delays in radio resource allocation, especially when the load of a supporting cell is high, and do not consider content-specific classification.
Innovation Solution
A technique for a terminal apparatus and base station apparatus that enables efficient D2D communication by implementing a mode selection process using timers and buffer status reports to autonomously switch communication modes, allowing for prioritization and efficient resource allocation based on D2D communication type, reducing the need for external base station intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station performs centralized radio resource allocation for D2D communication, then resource allocation reliability is improved, but resource allocation time increases and autonomy is reduced
Solution Approach 1:
The patent segments D2D communication resources into two distinct pools: Mode 1 resources allocated by base station and Mode 2 resources selected autonomously by terminal. This segmentation allows the system to switch between centralized and autonomous allocation modes, resolving the contradiction by enabling fast autonomous selection (Mode 2) while maintaining reliability through base station control (Mode 1) when needed.
Solution Approach 2:
The patent implements dynamic mode switching between Mode 1 and Mode 2 based on communication type priority and base station load conditions. High-priority D2D communications can switch to Mode 2 for immediate resource selection, while low-priority communications use Mode 1 for centralized allocation, making the system adaptable to varying conditions and resolving the time-reliability tradeoff.
2Productivity
If the terminal autonomously selects radio resources for D2D communication, then resource allocation speed is improved, but resource allocation reliability deteriorates
Solution Approach 1:
The patent enables terminals to autonomously select resources from Mode 2 pools without base station intervention, achieving fast resource allocation. The terminal independently monitors resource availability and selects appropriate resources, improving allocation speed while the dual-mode architecture ensures reliability through fallback to Mode 1 when necessary.
Solution Approach 2:
The base station acts as an intermediary that configures Mode 2 resource pools and receives notifications from terminals about their autonomous selections. This intermediary role allows the terminal to operate autonomously for speed while maintaining system-wide coordination and reliability through base station oversight.
3Device complexity
If the base station load is high, then centralized resource allocation capacity is reduced, but autonomous mode switching capability is not utilized
Solution Approach 1:
The base station pre-configures Mode 2 resource pools in advance, so when load is high, terminals can immediately select from pre-prepared resources without requiring real-time base station processing. This preliminary action reduces base station processing load during high-traffic periods while maintaining efficient resource allocation.
Solution Approach 2:
The system changes the allocation mode parameter based on base station load conditions. When load exceeds thresholds, the system transitions from Mode 1 (base station-controlled) to Mode 2 (autonomous selection), dynamically adjusting the allocation mechanism to match system conditions and improve overall efficiency.
4Ease of operation
If mode switching is implemented without considering D2D communication type, then switching simplicity is improved, but communication priority handling deteriorates
Solution Approach 1:
The patent applies different quality characteristics to different D2D communication types by assigning priority levels (first priority for public safety, second priority for other services). High-priority communications are granted preferential access to Mode 2 resources, while low-priority communications use Mode 1, ensuring that critical communications receive the reliability they need while maintaining simple mode switching operations.
Data Source
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AI summary
Provided is a technique related to a terminal apparatus, a base station apparatus, a communication system, a communication method, and an integrated circuit that are capable of efficiently performing device-to-device communication. In a case where a terminal apparatus capable of direct communication between terminal apparatuses starts a timer corresponding to a group index that identifies short-range group communication, to which the terminal apparatus belongs, and the timer expires, switching is performed from a first radio resource allocation method, by which a radio resource to be used for the direct communication is requested to a base station apparatus, to a second radio resource allocation method by which the terminal apparatus selects a radio resource to be used for the direct communication.