Interference Alignment Precoding for Base Station Inter-Cell Interference
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Solution Overview
Problem
Dynamic TDD systems face significant inter-cell interference due to constant transmission power of base stations, leading to low spectral efficiency and system throughput, as simple interference cancellation methods sacrifice transmission opportunities.
Innovation Solution
Implementing an interference alignment-based transmission method where each base station acquires and calculates a precoding matrix based on channel matrices between adjacent base stations, optimizing data transmission and reception to align interference into a common subspace for effective cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If simple interference cancellation schemes (TDM or FDM) are used, then inter-cell interference is avoided, but spectral efficiency and system throughput are reduced due to sacrificed transmission opportunities
Solution Approach 1:
The patent applies interference alignment to convert harmful inter-cell interference into a manageable form by aligning interference signals from multiple base stations into a common subspace at the receiving base station. This allows the receiver to separate desired signals from aligned interference through subspace projection, thereby maintaining high spectral efficiency while effectively canceling interference without sacrificing transmission opportunities
Solution Approach 2:
The patent transforms the interference cancellation problem from the time-frequency domain to the signal subspace domain. By projecting signals into different subspaces (desired signal subspace vs. interference subspace), the system can separate and cancel interference while maintaining full transmission opportunities, thus resolving the contradiction between interference avoidance and spectral efficiency
2Power
If base stations transmit with constant high power, then transmission coverage is maintained, but inter-cell interference increases and adversely affects uplink data reception
Solution Approach 1:
The patent applies local quality by designing cell-specific precoding matrices that create directional beamforming patterns. Each base station transmits with high power in its intended direction while minimizing interference to neighboring cells through spatial filtering. The precoding matrices are specifically designed to nullify or reduce interference in directions where other base stations are located, thus maintaining transmission power while reducing inter-cell interference
3Adaptability or versatility
If dynamic TDD UL/DL configuration is implemented, then traffic adaptive requirements are met, but serious inter-cell interference occurs due to different configurations in adjacent cells
Solution Approach 1:
The patent applies dynamics by making the precoding matrices adaptive to changing channel conditions and interference environments. The system continuously updates precoding matrices based on current channel state information and interference alignment requirements, allowing dynamic TDD configurations to coexist with effective interference cancellation. This enables the system to maintain traffic adaptability while dynamically adjusting precoding to mitigate interference from neighboring cells with different configurations
Data Source
AI summary
The present disclosure provides a base station, a communication system and a method thereof. The communication system includes three base stations adjacent to each other, and each base station serves at least one UE. The method includes: acquiring, by each base station, a channel matrix of a channel from the base station to an adjacent base station; calculating an interference alignment-based transmission precoding matrix for each base station based on the channel matrices of the channels between the base stations; and precoding, by each base station, data to be transmitted with the interference alignment-based transmission precoding matrix.