LTE Proximity Reference Signaling for Low-Power UE Detection
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Solution Overview
Problem
Existing LTE systems lack mechanisms for UEs to determine the proximity of other UEs and establish device-to-device communication efficiently, leading to battery consumption and security concerns in beaconing and scanning methods.
Innovation Solution
Implementing proximity reference signals (Prox-RS) configured by eNBs for UEs to transmit and detect, allowing network-based feedback for proximity determination and resource allocation, using patterns and IDs to minimize battery usage and collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beaconing and scanning methods are used for proximity detection, then UEs can determine proximity of other UEs, but battery consumption increases
Solution Approach 1:
The patent implements periodic proximity reference signal transmissions at configured intervals rather than continuous beaconing. The eNB configures specific subframes and periods for Prox-RS transmission, allowing UEs to detect proximity events periodically while conserving battery power during non-active periods.
Solution Approach 2:
The system enables UEs to autonomously detect proximity events by monitoring configured Prox-RS resources without requiring continuous network coordination. Once configured, UEs independently perform detection and reporting based on pre-configured parameters, reducing ongoing energy expenditure.
2Adaptability or versatility
If beaconing and scanning methods are used for proximity detection, then UEs can establish device-to-device communication, but security concerns arise
Solution Approach 1:
The eNB acts as an intermediary that configures and controls the proximity detection process. The network provides configuration parameters, validates proximity reports, and authorizes device-to-device communication establishment, ensuring security through network-mediated control rather than direct peer-to-peer discovery.
Solution Approach 2:
The system implements a feedback mechanism where UEs report detected proximity events to the eNB, which then provides authorization decisions. This closed-loop feedback ensures that device-to-device communication is only established when the network validates the proximity claim and deems it secure.
3Measurement precision
If proximity reference signals are transmitted frequently, then proximity detection accuracy improves, but resource usage increases
Solution Approach 1:
The patent applies different transmission configurations to different UEs based on their specific needs and conditions. The eNB can assign different periods, subframes, and power levels to individual UEs or groups, optimizing resource usage locally rather than applying a uniform configuration to all devices.
Solution Approach 2:
The system dynamically adjusts transmission parameters including periodicity, subframe allocation, and power levels based on detected proximity events and network conditions. When proximity is detected, the system can increase detection frequency locally; when no events occur, resources are reduced, optimizing the balance between accuracy and resource consumption.
Data Source
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AI summary
A method at a first user equipment, UE, (120), is disclosed. The method comprises: monitoring time/frequency resources based on configuration information for receiving proximity reference signals, Prox-RS, the configuration information defining the time/frequency resources. The method comprises detecting the Prox-RS received using the time/frequency resources, the Prox-RS transmitted by a second user equipment for determining whether the first and second UEs are in proximity to each other.