Wireless Device Reference Signal Selection for MPE Compliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, especially at high frequencies, wireless devices (WDs) face challenges in efficiently managing beam selection and power control due to maximum permissible emission (MPE) limitations, which can lead to reduced UL coverage and performance, as current reporting mechanisms do not provide sufficient information for network nodes to effectively switch between antenna panels or beams.
Innovation Solution
The WDs are configured to select and report candidate downlink reference signals, including quality information and power management maximum power reduction (P-MPR) values, allowing network nodes to select the most suitable beam for uplink transmissions, thereby improving beam selection and power management during MPE events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the WD reports only basic MPE status without candidate reference signals, then the reporting mechanism is simple, but the network node cannot effectively switch between antenna panels or beams
Solution Approach 1:
The WD performs preliminary identification and reporting of candidate downlink reference signals before the network node needs to switch beams. This advance preparation provides the network node with ready-to-use beam options when MPE events occur, enabling faster adaptation without requiring complex real-time analysis.
Solution Approach 2:
The WD provides feedback to the network node about suitable candidate reference signals based on its measurements and MPE status. This feedback loop enables the network node to make informed beam switching decisions by receiving quality information about alternative beams from the WD that has direct knowledge of current channel conditions.
2Reliability
If the WD uses a single antenna panel for uplink transmissions, then the device complexity is reduced, but the uplink coverage is reduced during MPE events
Solution Approach 1:
The WD divides its antenna system into multiple independent antenna panels, each capable of forming beams independently. This segmentation allows the WD to switch between panels when MPE events occur, maintaining uplink coverage by using alternative panels that are not subject to the same exposure limitations as the current panel.
Solution Approach 2:
The WD changes operational parameters by switching between different antenna panels and their associated beams based on MPE status. When one panel reaches its power limit due to MPE constraints, the WD can switch to another panel with different spatial characteristics, effectively changing the transmission parameters to maintain coverage.
3Power
If the network node schedules transmissions without considering MPE limitations, then the scheduling efficiency is high, but the transmit power must be reduced to comply with exposure requirements
Solution Approach 1:
The network node receives advance information from the WD about candidate reference signals and their associated quality metrics before scheduling transmissions. This preliminary information allows the network node to pre-select beams that will maintain adequate transmit power even when MPE limitations are present, avoiding later power reductions that would hurt scheduling efficiency.
Solution Approach 2:
The network node changes scheduling parameters by selecting different spatial relations and beams based on the candidate reference signals reported by the WD. This allows the network to maintain higher transmit power by choosing beams with better propagation characteristics or from antenna panels not affected by current MPE constraints.
Data Source
AI summary
A method, network node and wireless device (WD) for reference signal selection and use at power limitation are disclosed. According to one aspect, a method in a wireless device, WD, configured to communicate with a network node is provided. The method includes determining that a maximum permissible emission event has occurred for a current spatial domain transmission filter of the WD, selecting at least one candidate downlink reference signal and reporting the selected candidate downlink reference signal to the network node.