D2D UE Synchronization Reference Selection for Path Loss Calculation
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Solution Overview
Problem
In device-to-device (D2D) wireless communication, especially in emergency situations where a network is not available, there is a challenge in calculating the path loss (PL) between user equipment (UEs) and controlling power transmission effectively without a reference signal from a base station, which affects synchronization and communication efficiency.
Innovation Solution
A method and apparatus for a UE to detect available synchronization signals, determine if it should operate as a synchronization reference UE, and transmit synchronization information, including intensity of transmission power, to enable D2D wireless communication, allowing other UEs to synchronize and adjust their transmission power based on received system information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If D2D communication is performed without network coverage, then communication availability is improved, but path loss calculation capability deteriorates due to lack of reference signal from base station
Solution Approach 1:
The patent introduces a synchronization reference UE as an intermediary entity that provides reference signals for path loss calculation in D2D communication. This mediator UE transmits synchronization signals and system information containing reference signal power, enabling other UEs to calculate path loss without direct base station coverage.
Solution Approach 2:
The patent enables UEs to self-organize and self-service by selecting synchronization reference UEs from among themselves. The UE autonomously determines whether to become a synchronization reference based on received signal strength, and other UEs autonomously calculate their own path loss using the reference signals from selected synchronization reference UEs.
2Reliability
If transmission power is increased to ensure communication coverage, then communication reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements feedback mechanisms where UEs measure the received signal strength from synchronization reference UEs and use this feedback to calculate path loss. This feedback loop enables dynamic transmission power adjustment, allowing UEs to transmit at minimum necessary power while maintaining communication reliability.
Solution Approach 2:
The patent changes the transmission power parameter dynamically based on calculated path loss and communication requirements. Instead of using fixed high power, the system adjusts transmission power parameters according to the measured channel conditions and path loss, reducing energy consumption while maintaining reliability.
3Area of stationary object
If multiple UEs transmit synchronization signals simultaneously, then synchronization coverage is improved, but interference increases
Solution Approach 1:
The patent applies preliminary action by having UEs select synchronization reference UEs before transmitting their own synchronization signals. UEs first measure and evaluate existing synchronization signals, then decide whether to become synchronization references based on this preliminary assessment, which helps coordinate transmissions and reduce interference.
Solution Approach 2:
The patent introduces dynamics by allowing the set of synchronization reference UEs to change over time based on communication conditions. UEs can dynamically switch between being synchronization references and regular UEs, and the system adapts the synchronization structure to balance coverage area with interference levels.
Data Source
AI summary
A user equipment (UE) is provided. The UE supports D2D wireless communication and includes a communication module configured to communicate with at least one different UE, a non-transitory computer readable memory storage configured to store instructions, and at least one processor electrically connected to the communication module and the memory storage. The instructions, when executed by the UE, cause the processor to check whether an available first synchronization signal is detected, determine whether to operate as a first synchronization reference UE based on whether the first synchronization signal is detected, and transmit first system information comprising an intensity of transmission power and a second synchronization signal comprising a first synchronization identifier if the UE is determined to operate as the first synchronization reference UE.