Transmit Spatial Filter Switching for MPE Compliance
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Solution Overview
Problem
Radio link failures and connection releases occur due to the unpredictable application of Power Management Maximum Power Reduction (P-MPR) in wireless terminals operating in mmWave frequencies, which violates Maximum Permitted Exposure (MPE) limits.
Innovation Solution
The proposed solution involves a method in wireless terminals to switch from a first transmit spatial filter to a second transmit spatial filter, while maintaining the first receive spatial filter, based on trigger events such as proximity detection, to manage uplink output power and avoid P-MPR application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Power Management Maximum Power Reduction (P-MPR) is applied to ensure MPE compliance, then MPE limits are satisfied, but radio link failures and connection releases occur due to significant and unpredictable power reduction
Solution Approach 1:
The patent applies dynamics by making the transmit spatial filter configurable and switchable based on proximity detection. Instead of statically applying P-MPR power reduction, the system dynamically adjusts the transmit direction using different spatial filters (first spatial filter when far, second spatial filter when close) to maintain reliable communication while complying with MPE limits.
Solution Approach 2:
The patent changes the parameter of transmit spatial filter selection based on detected proximity. When proximity exceeds a threshold, the system switches from a first transmit spatial filter to a second transmit spatial filter, thereby changing the transmission characteristics to reduce exposure without causing link failures.
2Reliability
If beamforming is used to improve signal to noise ratio in mmWave frequencies, then transmission efficiency is improved, but Maximum Permitted Exposure (MPE) restrictions are violated due to concentrated signal energy
Solution Approach 1:
The system dynamically switches between different transmit spatial filters based on real-time proximity detection. When the UE is detected to be close to the user's body, the system transitions from a first spatial filter (optimized for SNR) to a second spatial filter (optimized for MPE compliance), thereby adaptively managing both communication quality and safety exposure.
Solution Approach 2:
The patent applies local quality by using different spatial filters for different operational conditions. The first spatial filter is optimized for general communication quality, while the second spatial filter is specifically optimized for scenarios where proximity to the user's body is detected, creating localized optimization for MPE compliance in specific spatial regions.
3Ease of operation
If a first transmit spatial filter is used for connection, then initial connection is established, but radio link failure occurs when proximity detection triggers P-MPR application
Solution Approach 1:
The system performs preliminary action by detecting proximity in advance and proactively switching from the first transmit spatial filter to the second transmit spatial filter before P-MPR would be triggered. This preventive switching avoids the unpredictable power reduction and potential link failures that would occur with sudden P-MPR application.
Solution Approach 2:
The patent implements feedback through continuous proximity detection that informs spatial filter selection. The proximity detection feedback triggers automatic switching between spatial filters, creating a closed-loop system that maintains reliable connection by adapting transmit characteristics based on real-time proximity information.
Data Source
AI summary
Method carried out in a wireless terminal for managing connection to an access network (120), comprising: connecting (501) with the access network using a first transmit spatial filter and a first receive spatial filter; obtaining (50) information associated with a trigger event to switch uplink transmit direction; switching (514), based on said trigger event, from the first transmit spatial filter to a second transmit spatial filter, while maintaining the first receive spatial filter.