Adaptive Precoder for Multi-Antenna Interference Cancellation
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Solution Overview
Problem
Multiuser multi-antenna systems face challenges in achieving high performance while maintaining low complexity, particularly in canceling interference among terminals without requiring coordinated information and incurring excessive complexity.
Innovation Solution
A precoder system that includes a channel checker for determining DownLink channel conditions, a pre-compensator for selecting a nonlinear algorithm based on channel state information feedback, and an interference remover for canceling interference by multiplying signals with inverse channels, thereby reducing interference without needing coordinated information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear interference cancellation schemes (ZF or MMSE) are used, then implementation complexity is reduced, but performance degradation occurs due to transmitting signal power enhancement
Solution Approach 1:
The patent applies dynamic precoding by adaptively selecting between different precoding schemes (linear ZF/MMSE and nonlinear block diagonalization) based on channel conditions and terminal feedback. The base station dynamically adjusts the precoding matrix according to the selected scheme, enabling the system to transition between complexity and performance trade-offs in real-time based on current system state
2Reliability
If nonlinear interference cancellation schemes (dirty paper coding) are used, then performance is improved by canceling interference among users, but transmitting end complexity increases significantly
Solution Approach 1:
The patent segments the interference cancellation process into two parts: (1) the base station performs linear precoding to reduce but not completely eliminate interference, and (2) terminal devices perform iterative interference cancellation using received signal and channel state information. This segmentation distributes computational complexity from the base station to distributed terminals, achieving nonlinear interference cancellation performance with reduced centralized complexity
3Device complexity
If block diagonalization is used to cancel interference, then transmitting end complexity is reduced compared to dirty paper coding, but coordinated information must be transmitted to each user
Solution Approach 1:
The patent extracts and removes the need for coordinated information transmission by designing a precoding scheme where terminals independently perform interference cancellation using locally available channel state information and received signals. The block diagonalization structure is modified to eliminate the requirement for sending decoding information to each user, thereby removing the information overhead while maintaining reduced complexity
Data Source
AI summary
A precoder and a precoding method in a multiuser multi-antenna system are provided. The precoder includes a channel checker for determining a DownLink (DL) channel condition of terminals in a service coverage area, a pre-compensator for pre-compensating, for channel distortion, signals to be sent to the terminals when a nonlinear algorithm is selected based on the channel condition of the terminals, and an interference remover for canceling interference in a channel by multiplying the pre-compensated signals by inverse channels of the terminals, and for canceling interference between the terminals. Accordingly, the pre-equalization can be carried out without global channel state information, and an increase of the transmit power can be prevented in the permutation.