Frequency Domain Interference Cancellation for Cellular Systems
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Solution Overview
Problem
Conventional downlink cellular systems face high implementation complexity and power consumption due to performing interference cancellation, channel equalization, and signal reconstruction in the time domain, which is inefficient for addressing multipath and co-channel interference.
Innovation Solution
The method involves converting time domain signals into the frequency domain, storing frequency domain segments, and directly removing interference components from the frequency domain, reducing complexity and power consumption by maintaining operations in the frequency domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interference cancellation, channel equalization, and signal reconstruction are performed in the time domain, then the operations can be completed, but the implementation complexity and power consumption increase significantly
Solution Approach 1:
The patent transforms the domain parameter from time domain to frequency domain for performing interference cancellation and equalization operations. This parameter change fundamentally alters the computational characteristics, reducing the number of operations required while maintaining cancellation effectiveness.
Solution Approach 2:
The patent replaces the conventional time-domain mechanical processing system with a frequency-domain processing system. By using frequency domain operations (such as FFT-based processing), the system achieves the same interference cancellation function with reduced computational complexity.
2Reliability
If interference cancellation, channel equalization, and signal reconstruction are performed in the time domain, then the operations can be completed, but the power consumption increases
Solution Approach 1:
The patent changes the operational domain from time to frequency, which reduces the computational burden of interference cancellation operations. This parameter transformation leads to fewer arithmetic operations and consequently lower power consumption in the processing device.
Solution Approach 2:
The patent substitutes time-domain computational operations with frequency-domain operations, which are more energy-efficient. The frequency domain processing requires fewer multiplications and additions, directly reducing power consumption while maintaining the same interference cancellation performance.
3Reliability
If conventional time domain operations are used for interference cancellation, then the processing can be performed, but the computational intensity is high
Solution Approach 1:
The patent transforms operations from the time domain to the frequency domain, changing the parameter space in which processing occurs. This transformation enables more efficient computation through properties of the frequency domain, such as convolution becoming multiplication, thereby improving computational efficiency.
Solution Approach 2:
The patent replaces time-domain computational mechanisms with frequency-domain mechanisms. By using Fast Fourier Transform (FFT) and frequency domain filtering, the system achieves the same interference cancellation results with significantly reduced computational intensity and faster processing.
Data Source
AI summary
Methods and apparatus are described for interference cancellation of interference components of a time domain signal in the frequency domain. A communications device receives a time domain sequence and generates overlapping time domain segments from the time domain sequence. The overlapping time domain segments are then converted to the frequency domain to generate frequency domain representations of the overlapping time domain segments. The frequency domain representations are stored in a residual memory, and interference components are directly removed from the frequency domain representations stored in the residual memory in the frequency domain.