Self-Interference Cancellation in Full Duplex Base Stations
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Solution Overview
Problem
In wireless communication systems that support full duplex transmission, various interferences caused by transmission and reception signals between terminals and base stations can be problematic, necessitating effective interference cancellation methods for reliable service provision.
Innovation Solution
A method and apparatus for performing self-interference cancellation (SIC) in a mobile communication system, specifically by dynamically allocating uplink and downlink resources for the same frequency band, and estimating the self-interference channel by separately estimating the non-linearity of the channel, allowing for efficient SIC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex transmission is implemented to improve frequency efficiency and system network improvement, then communication capacity is enhanced, but self-interference between transmission and reception signals deteriorates communication reliability
Solution Approach 1:
The patent segments the interference cancellation process into multiple stages: analog self-interference cancellation in the RF domain and digital self-interference cancellation in the baseband domain. This segmentation allows each stage to handle specific aspects of interference, with analog cancellation addressing strong signal interference and digital cancellation refining the cancellation for weaker residual interference, thereby resolving the contradiction between maintaining full duplex productivity and ensuring communication reliability
Solution Approach 2:
The patent introduces an intermediary self-interference cancellation mechanism that acts as a mediator between the transmitted signal and received signal. The base station generates a self-interference cancellation signal based on the transmitted signal and subtracts it from the received signal, effectively mediating the harmful interaction between transmission and reception signals while preserving the full duplex communication capability
2Reliability
If self-interference cancellation is performed to improve communication reliability, then signal integrity is enhanced, but system complexity increases
Solution Approach 1:
The patent divides the self-interference cancellation system into distinct functional modules: an analog self-interference cancellation module operating in the RF domain and a digital self-interference cancellation module operating in the baseband domain. This segmentation allows each module to be optimized independently and managed separately, reducing overall system complexity while maintaining high communication reliability
Solution Approach 2:
The patent performs preliminary self-interference cancellation in the analog domain before signal conversion to digital form. By removing the strongest interference component early in the signal chain, the subsequent digital cancellation process deals with much weaker residual interference, simplifying the computational requirements and reducing the complexity of the digital processing stage
3Measurement precision
If non-linearity of the self-interference channel is separately estimated to improve SIC efficiency, then cancellation accuracy is enhanced, but processing time increases
Solution Approach 1:
The patent performs preliminary estimation of the non-linearity characteristics of the self-interference channel during system calibration or idle periods, before actual communication occurs. This preliminary estimation allows the system to pre-compute compensation parameters that are then applied during normal operation, achieving high cancellation accuracy without adding processing delays to the communication signal path
Solution Approach 2:
The patent implements periodic updates of the non-linearity estimation at predetermined intervals or when channel conditions change significantly, rather than continuously updating during every transmission. This periodic action maintains high cancellation accuracy while minimizing the time overhead associated with estimation operations
Data Source
AI summary
The disclosure relates to a 5th generation (5G) or 6th generation (6G) communication system in wireless communication. A method for a base station supporting flexible duplex communication by dynamically allocating uplink and downlink resources for the same frequency band in a wireless communication system includes transmitting a pilot signal for estimating non-linearity of an SI channel through which a signal transmitted by the base station is received by the base station; estimating non-linearity of the SI channel based on the pilot signal received through the SI channel; correcting and transmitting a DMRS, which is used for demodulating a signal received by a terminal from the base station, based on the estimated non-linearity of the SI channel; estimating the SI channel based on the corrected DMRS received through the SI channel; and performing communication with a plurality of terminals by cancelling SI based on the estimated SI channel.