UE Interference Cancellation Using Residual Frequency Offset Compensation
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Solution Overview
Problem
Satellite communication systems face significant interference due to cell-specific reference signal overlap, leading to deteriorated performance of user equipment (UE) and network performance, especially when frequency offset differences between serving and interference cells are large, which conventional methods like FeICIC cannot effectively address.
Innovation Solution
The UE divides the frequency offset difference into a subcarrier offset and a residual frequency offset, performing interference signal removal operations based on these offsets to compensate for the frequency difference, including first, second, and third interference signal removing operations tailored to different residual frequency offset conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interference signal removing methods (FeICIC) are used, then interference signals can be removed under ideal frequency alignment conditions, but performance deteriorates when frequency offset differences between serving and interference cells are large
Solution Approach 1:
The frequency offset difference is segmented into two distinct components: subcarrier offset (integer multiple of SCS) and residual frequency offset (non-integer portion). This segmentation allows the system to apply different processing strategies to each component - the subcarrier offset is compensated through standard frequency alignment, while the residual frequency offset is handled through specialized interference signal removing operations, thereby maintaining reliability across various frequency offset conditions
Solution Approach 2:
The system changes the parameter representation of frequency offset from a single continuous value to a discrete-continuous hybrid representation (subcarrier offset index + residual offset value). This parameter transformation enables the interference signal removing operation to effectively handle large frequency offset differences by adjusting the residual frequency offset compensation based on the detected offset magnitude, thus improving adaptability while maintaining removal performance
2Manufacturing precision
If the entire frequency offset difference is compensated through standard frequency alignment, then subcarrier alignment is achieved, but residual frequency offset remains causing interference
Solution Approach 1:
The invention extracts the residual frequency offset component from the total frequency offset after standard subcarrier alignment. By separating this residual component, the system can apply dedicated interference signal removing operations that specifically address the remaining offset effects, thereby maintaining both subcarrier alignment precision and interference removal effectiveness
Solution Approach 2:
The system performs preliminary subcarrier alignment through standard frequency compensation methods before applying the interference signal removing operation. This preliminary action establishes a baseline alignment that simplifies the subsequent residual offset handling, allowing the interference removal algorithm to focus specifically on the remaining non-integer offset effects
3Reliability
If multiple interference signal removing operations are performed to handle different offset conditions, then comprehensive interference removal is achieved, but processing complexity increases
Solution Approach 1:
The system dynamically selects and applies different interference signal removing operations based on the detected residual frequency offset characteristics. Rather than always performing the most complex operation, the system adapts its processing level to the actual offset conditions, achieving comprehensive interference removal while minimizing unnecessary processing complexity through conditional operation selection
Data Source
AI summary
Provided are a user equipment (UE) for removing an interference signal caused by an adjacent cell and an operating method of the UE. The operating method of the UE communicating with a base station (BS) includes calculating a frequency offset difference between a serving cell and an interference cell based on a first frequency offset for the serving cell and a second frequency offset for the interference cell, the frequency offset difference including a subcarrier offset and a residual frequency offset, the subcarrier offset being an integer multiple of a subcarrier spacing (SCS), and removing an interference signal from a reception signal received by the UE by compensating for the frequency offset difference based on the residual frequency offset.