D2D Transmission Mode Selection for Edge-of-Coverage UEs
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Solution Overview
Problem
Current D2D communication technologies in LTE networks lack clear criteria for determining edge-of-coverage UE behavior and resource allocation modes, leading to inefficiencies in Mode 1 and Mode 2 selection for D2D communication.
Innovation Solution
Proposed methods for D2D transmission mode selection, allowing UEs to autonomously or eNB-configuredly switch between Mode 1 and Mode 2 based on radio resource control and channel conditions, using metrics like signal strength and connection attempts to determine network connection status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If UEs autonomously select transmission modes in Mode 2, then device complexity and network load are reduced, but resource allocation efficiency and communication reliability deteriorate at edge-of-coverage and out-of-coverage locations
Solution Approach 1:
The patent implements dynamic transmission mode selection where UEs can switch between Mode 1 (eNB-configured) and Mode 2 (autonomous) based on real-time radio conditions and coverage status. This dynamic adaptation allows the system to optimize between complexity and reliability by selecting the appropriate mode for current operational conditions, particularly at edge-of-coverage locations where conditions change frequently.
Solution Approach 2:
The patent employs feedback mechanisms where UEs monitor radio conditions, connection status, and coverage state, then use this information to determine whether to operate in Mode 1 or Mode 2. The feedback loop includes monitoring uplink connection status, downlink signal quality, and transitioning between modes based on predefined thresholds and conditions, ensuring reliable operation while managing complexity.
2Reliability
If UEs use Mode 1 with eNB-configured resources, then resource allocation efficiency and communication reliability are improved, but network load and control signaling overhead increase
Solution Approach 1:
The patent segments the D2D communication operation into two distinct modes: Mode 1 for in-coverage scenarios where eNB control is available, and Mode 2 for out-of-coverage or edge scenarios where autonomous operation is appropriate. This segmentation allows the system to apply centralized control only when necessary (reducing overall network load) while maintaining reliability in controlled environments.
Solution Approach 2:
The patent enables UEs to self-select and self-configure transmission parameters in Mode 2, reducing dependency on continuous eNB control and signaling. UEs autonomously select resources from pre-configured pools, determine transmission power, and manage their own D2D communication operations, thereby significantly reducing network load and signaling overhead while maintaining operational capability.
3Device complexity
If simple TDM allocation is used between D2D and WAN, then implementation complexity is reduced, but D2D communication performance and resource utilization deteriorate at edge-of-coverage locations
Solution Approach 1:
The patent applies local quality by implementing different resource allocation strategies for different geographical and operational contexts: simple TDM allocation for central in-coverage areas where performance requirements are met, and enhanced dynamic mode selection with flexible resource pools for edge-of-coverage and out-of-coverage areas where performance optimization is critical. This localized approach optimizes performance where needed without unnecessarily increasing complexity elsewhere.
Data Source
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AI summary
A user equipment (UE) includes a transmission mode component, a selection component, and a transmission component. The transmission mode component is configured to selectively allocate resources for device-to-device communication according to a plurality of transmission modes. The plurality of transmission modes include a first transmission mode in which the resources used by the UE are specifically allocated by one of a base station or relay node and a second transmission mode in which the UE selects the resources from a pool of available resources. The selection component is configured to select a selected transmission mode. The transmission component is configured to transmit signals in frequency resources selected according to the selected transmission mode.