Interference Reduction Control Information for LTE-Advanced User Apparatus
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Solution Overview
Problem
In LTE-Advanced radio communication systems, user apparatuses face challenges in performing Interference Rejection Combining (IRC) Type 1 and Successive Interference Cancellation (SIC) due to a shortage of necessary information for high interference reduction ability, particularly for control channels that cause interference.
Innovation Solution
The system dynamically or semi-statically sends necessary information from the network side to the user apparatus, using control channels or RRC signaling, to enable effective IRC Type 1 and SIC operations, including channel estimation and interference signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the user apparatus performs interference reduction processing using IRC Type 1 or SIC, then the reception quality of the desired signal is improved, but the user apparatus cannot acquire sufficient information for effective interference reduction
Solution Approach 1:
The base station acts as an intermediary to bridge the information gap. It extracts interference-related information (interference base station ID, resource allocation, modulation scheme) from the interference signal and delivers it to the user apparatus through downlink control channels or higher-layer signaling, enabling the user apparatus to perform effective interference reduction without having direct access to all necessary information
Solution Approach 2:
The base station performs preliminary processing by identifying interference signals and extracting relevant information before transmitting it to the user apparatus. This advance preparation of interference information allows the user apparatus to execute interference reduction algorithms more effectively without having to discover and process all interference characteristics independently
2Reliability
If the user apparatus attempts to independently identify and reduce interference signals, then interference reduction capability is enhanced, but the complexity of the user apparatus increases
Solution Approach 1:
The base station serves as an information intermediary that performs the complex task of identifying and characterizing interference signals. By delivering pre-processed interference information to the user apparatus, the base station enables reliable interference reduction while keeping the user apparatus complexity manageable, as the user apparatus only needs to implement the interference reduction algorithm using provided information rather than independently discovering all interference characteristics
3Measurement precision
If more interference information is transmitted from the base station to the user apparatus, then interference reduction performance improves, but the downlink control overhead increases
Solution Approach 1:
The base station extracts only the essential interference-related information (interference base station ID, resource allocation, modulation scheme) needed for effective interference reduction, rather than transmitting complete interference signal data. This selective extraction provides sufficient information for interference reduction while minimizing the overhead on downlink control channels
Solution Approach 2:
The interference information is tailored specifically for the user apparatus's needs in its local environment. The base station identifies and transmits only the interference characteristics relevant to each user apparatus's reception conditions, avoiding transmission of unnecessary information and optimizing the balance between interference reduction performance and control overhead
Data Source
AI summary
A user apparatus in a radio communication system including a plurality of base stations, including a reception unit that receives, from a connecting base station, control information to be used for reducing a signal of a control channel, that causes interference, sent from an interference base station for the user apparatus, and an interference reducing unit that reduces the signal of the control channel that causes the interference by using the control information to obtain a desired signal sent from the connecting base station.