IAB Node PDSCH Power Offset Control for Crosslink Interference
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Solution Overview
Problem
Conventional IAB nodes face challenges in achieving simultaneous transmission and reception operations between IAB-DU and IAB-MT due to crosslink-interference, limiting system capacity and increasing latency.
Innovation Solution
The method involves adjusting the transmission power of physical downlink shared channels (PDSCH) by deriving and applying power offsets based on information exchanged between IAB nodes, using MAC control elements, and considering beam-specific adjustments to alleviate cross-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous transmission and reception between IAB-DU and IAB-MT are allowed, then system capacity is increased and latency is minimized, but crosslink-interference is caused
Solution Approach 1:
The patent applies different power offset adjustments to different beams and channels. Specifically, it adjusts the transmission power of PDSCH relative to CSI-RS on a per-beam basis using beam-specific power offsets, and applies different power relationships to different channel types (PDSCH vs PUCCH vs PUSCH). This localized power adjustment resolves the contradiction by suppressing interference in specific directions while maintaining capacity in others.
Solution Approach 2:
The patent changes the power parameter of transmitted signals by introducing power offset adjustments. The IAB-MT reports required power offsets to the IAB-DU, which then applies these offsets to adjust PDSCH transmission power relative to CSI-RS. This parameter change enables simultaneous transmission and reception by dynamically controlling power levels to minimize crosslink-interference while maintaining system capacity.
2Object-affected harmful factors
If power offset adjustment is applied to all beams, then crosslink-interference is reduced, but transmission efficiency on other beams is degraded
Solution Approach 1:
The patent implements beam-specific power offset adjustments rather than uniform adjustment across all beams. The IAB-DU applies power offsets selectively to specific beams where crosslink-interference is detected, while maintaining normal power levels on other beams. This resolves the contradiction by locally suppressing interference only where necessary, preserving transmission efficiency on unaffected beams.
3Object-affected harmful factors
If transmission power is adjusted based on beam-specific information, then crosslink-interference is minimized, but signaling overhead increases
Solution Approach 1:
The patent applies power offset adjustment only to the necessary extent - specifically to PDSCH transmission relative to CSI-RS, and only on beams where interference is detected. The IAB-MT reports power offset requirements only when needed, and the IAB-DU applies adjustments selectively rather than universally. This partial action resolves the contradiction by minimizing signaling overhead while still achieving interference suppression where necessary.
Data Source
AI summary
Disclosed are a method and a device for transmission or reception of an integrated access backhaul node. An operation method of a first IAB node comprises the steps of: receiving information of a power offset from a second IAB node; deriving a first EPRE of a PDSCH transmitted by the second IAB node on the basis of the power offset; transmitting, to the second IAB node, a first message requesting adjustment of transmission power of the PDSCH; receiving, from the second IAB node, a second message including information on the adjusted transmission power of the PDSCH; and applying the adjusted transmission power to the first EPRE, so as to derive the adjusted EPRE of the PDSCH.