Electronic Device Random Access Procedure SAR Management
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Solution Overview
Problem
In the context of 5G communication, especially in scenarios involving dual connectivity (DC) and DFT-s-OFDM, the possibility of failure for random access (RA) procedures is high due to reduced transmission power caused by specific absorption rate (SAR) limitations, leading to unnecessary power and resource wastage.
Innovation Solution
An electronic device that determines whether to perform a random access procedure based on a previously occurred specific absorption rate (SAR), receiving messages for RA procedures on a second cell using a different radio access technology (RAT) while connected to a first cell, and decides to transmit or refrain from transmitting an RA preamble message accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user device consistently performs the RA procedure, then the RA procedure can be attempted, but power and resources are wasted unnecessarily due to high failure probability caused by SAR-limited transmission power
Solution Approach 1:
The device performs preliminary assessment of accumulative SAR before initiating the RA procedure. By evaluating the current SAR state in advance, the device determines whether transmission power will be sufficient for successful RA, thereby avoiding unnecessary power consumption when failure is highly probable
Solution Approach 2:
The device continuously monitors and accumulates SAR values from previous transmissions and uses this feedback to dynamically decide whether to proceed with the RA procedure. This feedback mechanism allows the device to adapt its RA transmission decisions based on historical SAR data, preventing energy waste when SAR levels indicate likely failure
2Object-affected harmful factors
If the maximum transmission power is backed off according to SAR limit, then SAR compliance is maintained, but the RA procedure failure probability increases
Solution Approach 1:
The device dynamically adjusts its RA transmission strategy based on current SAR conditions. When accumulative SAR is low, the device can transmit at higher power for better RA success. When accumulative SAR is high, the device backs off transmission power to maintain SAR compliance, even though this increases RA failure probability. This dynamic adaptation resolves the contradiction by making power levels responsive to real-time SAR conditions
3Adaptability or versatility
If DFT-s-OFDM is executed, then communication compatibility is maintained, but the RA procedure failure probability increases further due to SAR limitations
Solution Approach 1:
The device changes transmission parameters (power level, timing) based on SAR conditions when executing DFT-s-OFDM. By adjusting these parameters dynamically, the device maintains compatibility with DFT-s-OFDM requirements while attempting to compensate for the reduced reliability caused by SAR-limited power backing off
Data Source
AI summary
According to various embodiments, an electronic device may include: at least one processor, wherein the at least one processor is configured to: receive at least one message causing a random access (RA) procedure for a second cell based on a second radio access technology (RAT) different from a first RAT while being connected to a first cell based on the first RAT, identify, based on the reception of the at least one message, a first accumulative specific absorption rate (SAR) having occurred based on transmission of at least one RF signal based on the first RAT and/or the second RAT for a first time interval, transmit an RA preamble message to the second cell based on determining, based on the first accumulative SAR, that performing the RA procedure for the second cell based on the second RAT is possible, and refrain from transmitting the RA preamble message based on determining, based on the first accumulative SAR, that performing the RA procedure for the second cell based on the second RAT is impossible.