Terminal Device NAICS Interference Cancellation via MCS Field Segmentation
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Solution Overview
Problem
In wireless communication systems, the difficulty in acquiring the modulation and coding scheme (MCS) of interfering terminal devices hinders precise interference signal cancellation, leading to degraded reception performance in high-density base station arrangements and multi-user MIMO environments.
Innovation Solution
A terminal device and base station apparatus configuration that interprets and transmits specific MCS fields within downlink control information to identify and cancel interference signals, allowing for precise modulation scheme determination and suppression of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device uses NAICS to cancel interference signals, then reception performance should improve, but the MCS of interfering terminal devices cannot be acquired from downlink control information, making precise interference cancellation difficult
Solution Approach 1:
The patent segments the MCS field in downlink control information into a first MCS field for the terminal device itself and a second MCS field for interfering terminal devices. This segmentation allows the terminal device to separately access and interpret MCS information for different purposes: self-demodulation and interference cancellation, thereby resolving the information loss problem while maintaining reception performance
Solution Approach 2:
The patent introduces a second MCS field as an intermediary element in the downlink control information structure. This intermediary field specifically carries MCS information of interfering terminal devices, enabling the terminal device to acquire the necessary parameters for precise interference signal cancellation without compromising the primary function of the control information
2Productivity
If multiple terminal devices are spatially multiplexed in MU-MIMO to improve cell throughput, then spectral efficiency increases, but inter-user interference occurs
Solution Approach 1:
The patent converts the harmful inter-user interference into a beneficial resource by including MCS information of interfering terminal devices in the downlink control information. The terminal device uses this previously harmful interference data to construct accurate interference signal models, enabling precise cancellation and transforming the interference from a detrimental factor into a useful reference for maintaining high spectral efficiency in MU-MIMO systems
Solution Approach 2:
The patent implements a feedback mechanism where the base station includes MCS information of interfering terminal devices in the downlink control information transmitted to each terminal device. This feedback loop enables terminal devices to accurately identify and cancel interference signals, allowing the system to maintain high throughput while suppressing inter-user interference through informed interference management
Data Source
AI summary
A terminal device acquires a parameter indispensable in canceling or suppressing an interference signal, cancels or suppresses interference with high precision, and reduces a degradation in reception performance due to the interference. There is provided a first terminal device that communicates with a base station apparatus, including: a higher layer processing unit that determines NAICS information indicating whether or not NAICS has to be used; a reception unit that receives downlink control information which is transmitted from the base station apparatus; and a control unit that changes interpretation of the downlink control information based on a configuration that is determined by the higher layer processing unit, in which, in a case where a result of determining the NAICS information that is determined in the higher layer processing unit indicates that the NAICS has to be used, the control unit interprets the second MCS field as information indicating a modulation scheme of a second terminal device, among a first MCS field for a transport block 1 and a second MCS field for a transport block 2, which are included in the downlink control information.