Sub-band Transmit Power Adjustment for LBT Interference Mitigation
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Solution Overview
Problem
In radio-based access to unlicensed spectrum, adjacent band interference poses challenges for signal robustness, particularly in New Radio (NR) systems, where interference from adjacent sub-bands can weaken the received signal, affecting decoding and demodulation.
Innovation Solution
The method involves determining transmission power target levels and power offsets based on listen before talk (LBT) procedures, adjusting transmit power on specific sub-bands to counteract interference, thereby enhancing signal robustness and aiding receivers in decoding by boosting power on affected sub-bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmit power is increased on all sub-bands to counteract adjacent band interference, then signal robustness improves, but energy consumption increases and interference to other bands worsens
Solution Approach 1:
The patent applies local quality by adjusting transmit power specifically on sub-bands affected by adjacent band interference rather than uniformly across all sub-bands. The gNB identifies which sub-bands experience interference and applies power boosting only to those specific sub-bands, thereby improving signal robustness where needed while avoiding unnecessary energy consumption on unaffected sub-bands and minimizing interference to other bands.
2Reliability
If transmit power is increased to overcome interference, then decoding robustness improves, but interference to adjacent bands worsens
Solution Approach 1:
The patent implements local quality by applying power adjustment selectively only to sub-bands that are affected by adjacent band interference. The gNB identifies the specific sub-bands experiencing interference and boosts power only on those sub-bands, thereby improving decoding robustness locally without generating excessive interference to other adjacent bands that do not require additional power.
3Measurement precision
If listen before talk procedure is performed on all sub-bands, then interference detection accuracy improves, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the wideband carrier into multiple sub-bands and performing listen before talk procedures independently on each sub-band. This allows the system to identify which specific sub-bands are affected by adjacent band interference, improving interference detection accuracy while managing processing complexity through parallel independent evaluations rather than treating the entire bandwidth as a single unit.
Data Source
AI summary
A method includes determining, by a terminal device, at least one transmission power target level for an intended transmission on at least one sub-band. The method also includes performing a listen before talk procedure and measuring interference, and determining at least one power offset for transmission as outcome of the listen before talk procedure and the measured interference. The method further includes transmitting at least one message on at least one listen before talk allowed sub-band, using a transmission power determined based at least in part on the at least one transmission power target level for the intended transmission on the at least one sub-band, and the at least one power offset.