MUST Precoding and Power Allocation for Interference Cancellation
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Solution Overview
Problem
In communication systems like LTE, terminal devices face challenges in learning interference signal information and reducing inter-user interference to enhance throughput and communication opportunities, requiring efficient channel state information reporting and precoding matrix determination.
Innovation Solution
A terminal device and base station device configuration that includes a reception unit for CSI reports and a transmission unit for channel quality indicators, allowing for aperiodic CSI reporting and precoding matrix indicators to be exchanged, enabling the terminal device to effectively learn and mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminal devices are non-orthogonally multiplexed to perform transmission, then system capacity and communication opportunity are enhanced, but inter-user interference is caused
Solution Approach 1:
The patent converts the harmful inter-user interference into a beneficial element by having the terminal device calculate and report both the strongest and second strongest interference signal information to the base station. The base station then uses this previously harmful interference data to perform interference cancellation, transforming the interference problem into a solution that enables higher order modulation schemes and improves system capacity.
Solution Approach 2:
The patent implements a feedback mechanism where the terminal device measures interference signals, calculates interference information including CSI for both strongest and second strongest interference, and feeds this back to the base station. The base station uses this feedback to determine appropriate modulation schemes and perform interference cancellation, creating a closed-loop system that continuously optimizes performance while managing interference.
2Reliability
If the terminal device reports channel information to the base station for determining non-orthogonal multiplexing, then interference cancellation capability is improved, but feedback overhead and device complexity increase
Solution Approach 1:
The patent applies local quality by having the terminal device calculate different subband CQI values based on different interference cancellation scenarios. Specifically, it calculates CQI assuming only strongest interference cancellation and CQI assuming both strongest and second strongest interference cancellation, allowing the base station to make locally optimized decisions for different frequency subbands rather than using a uniform approach.
Solution Approach 2:
The patent segments the channel state information feedback into distinct components: strongest interference signal information, second strongest interference signal information, and multiple CQI values corresponding to different interference cancellation assumptions. This segmentation allows the base station to selectively process different levels of interference information based on channel conditions and terminal capabilities, reducing overall feedback complexity.
3Measurement precision
If the terminal device calculates channel quality indicator using different subband sizes for different report modes, then measurement precision is improved, but calculation complexity increases
Solution Approach 1:
The patent implements dynamic CQI calculation where the terminal device adapts the subband size and calculation method based on the configured report mode. When the report mode requests CQI based on the second strongest precoding matrix, the terminal dynamically adjusts to calculate CQI over appropriate subband sizes, balancing measurement precision with computational complexity based on real-time reporting requirements.
Data Source
AI summary
A base station device, a terminal device, and a communication method are provided, and the terminal efficiently learns information of an interference signal and reduces interference in a reception process to enhance throughput and enhance communication opportunity of each terminal device by feedback from the terminal. The base station device includes a transmission unit configured to transmit, to the terminal device, assist information of Multiuser Superposition Transmission (MUST), and the assist information includes information indicating whether precoding types of terminal devices configured with the MUST are identical to each other or different from each other. In a case that the information indicating whether the precoding types are identical to each other or different from each other indicates that the precoding types are identical to each other, transmit power is allocated at different power ratios to the terminal devices configured with the MUST, and in a case that the information indicating whether the precoding types are identical to each other or different from each other indicates that the precoding types are different from each other, the transmit power is allocated at identical power ratios to the terminal devices configured with the MUST.