UE SSB Interference Cancellation for PDSCH Decoding
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Solution Overview
Problem
Inter-cell interference limits the performance of the physical downlink shared channel (PDSCH) in 5G NR systems, leading to increased block error rates due to asynchronous interference from non-zero power CSI-RS and varying synchronization signal block (SSB) locations and numbers across cells.
Innovation Solution
A method is introduced where a user equipment (UE) decodes the SSB from a neighboring cell, determines overlap with the PDSCH, estimates the channel of the SSB, and removes the interfering SSB from the PDSCH, using known SSB symbols as pilots for improved channel estimation and interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SSB transmissions are performed in 5G NR systems, then synchronization and system information broadcast are achieved, but inter-cell interference occurs on PDSCH leading to increased block error rates
Solution Approach 1:
The patent converts the harmful interference from neighboring cell SSB transmissions into a beneficial process by having the UE decode the SSB, estimate its channel, reconstruct it, and subtract it from the received signal. This transforms the harmful interference into a known signal that can be removed, thereby improving PDSCH decoding reliability and reducing block error rates.
Solution Approach 2:
The patent applies preliminary action by having the UE decode the SSB from the neighboring cell in advance before attempting to decode the PDSCH. By performing SSB decoding, channel estimation, and interference reconstruction beforehand, the system prepares the received signal by removing the known interference component, which then enables more reliable PDSCH decoding.
2Adaptability or versatility
If SSB locations and numbers vary across cells, then network flexibility and adaptability are improved, but interference patterns become unpredictable and harder to manage
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously decode the SSB from the neighboring cell, estimate its channel characteristics, reconstruct the SSB signal, and subtract it from the received signal. This self-service approach allows the system to handle variable SSB configurations across cells without requiring complex network coordination or centralized interference management, thereby maintaining adaptability while managing complexity at the UE level.
3Duration of action of stationary object
If PDSCH decoding is performed in the presence of overlapping SSB, then communication continuity is maintained, but decoding accuracy decreases due to interference
Solution Approach 1:
The patent applies the extraction principle by separating the interfering SSB signal from the composite received signal. The UE extracts the SSB component through decoding, channel estimation, and reconstruction, then removes it from the received signal before decoding the PDSCH. This extraction process maintains communication continuity by enabling PDSCH decoding while improving decoding accuracy by eliminating the interference source.
Data Source
AI summary
A synchronization signal block (SSB) transmitted by a neighbor base station may interfere with a physical downlink shared channel (PDSCH) transmitted by a serving base station. A user equipment (UE) that receives both the SSB and PDSCH may mitigate the interference to improve an error rate of decoding the PDSCH. The UE may receive a first SSB including a first broadcast channel (BCH) from a second base station other than a serving base station. The UE may decode the first SSB. The UE may determine, based on the first SSB and the first BCH, that the PDSCH scheduled by the serving base station will overlap with a second SSB from the second base station. The UE may estimate a channel of the second SSB based on the decoded first SSB. The UE may remove a reconstructed second SSB from the PDSCH. The UE may decode the PDSCH.