Mixed Interference Estimation in Mobile Telecommunications
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Solution Overview
Problem
In the E-UTRAN mobile telecommunications system, the limited set of reference symbols and differing interference patterns between transmission resource elements, particularly in MIMO configurations, lead to poor interference statistics and inaccurate channel quality estimation, affecting data transmission and resource allocation.
Innovation Solution
The method involves using mixing parameters sent from the network node to the UE to combine interference estimates from different types of resource elements, such as data and reference symbols, allowing for a mixed interference estimate that accounts for varying interference effects across resource elements, and includes filtering to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference symbols are used for interference estimation, then interference can be measured, but the limited set of reference symbols results in poor interference statistics
Solution Approach 1:
The patent combines interference estimates from multiple resource element types (reference symbols, data symbols, control symbols) into a mixed interference estimate. This merging of different symbol types compensates for the limited number of reference symbols by incorporating additional measurement opportunities from other resource elements, thereby improving interference estimation accuracy.
Solution Approach 2:
The patent makes the interference estimation process universal by enabling measurement on multiple types of resource elements, not just reference symbols. The system can selectively use reference symbols, data symbols, or control symbols depending on availability and reliability, making the interference estimation mechanism more versatile and robust against limitations in any single resource element type.
2Measurement precision
If interference is estimated on common reference symbols, then interference measurement is possible, but the estimate does not reflect the interference situation for data transmission due to different power control
Solution Approach 1:
The patent applies local quality by creating different interference estimates for different resource element types (reference symbols, data symbols, control symbols) and then combining them with appropriate weighting. Each resource element type has its own interference characteristics due to different power control, and the patent preserves these local differences rather than using a single uniform estimate, thereby improving the representativeness of the overall interference measurement.
Solution Approach 2:
The patent changes the parameters of interference estimation by introducing mixing parameters that control the contribution of different resource element types. The network can dynamically adjust these parameters to reflect changing interference conditions and power control configurations, allowing the interference estimate to adapt to different transmission scenarios and maintain reliability.
3Ease of manufacture
If only three frequency shifts for common reference symbols are used in MIMO, then reference symbol allocation is simple, but not all data interference can be measured
Solution Approach 1:
The patent makes the interference measurement system universal by enabling measurement on multiple types of resource elements beyond just reference symbols. When reference symbols with limited frequency shifts are used, the system can supplement measurements with data symbols and control symbols, ensuring complete interference measurement coverage without requiring complex reference symbol allocation schemes.
4Ease of operation
If control channels occupy the first three OFDM symbols, then control signalling is transmitted, but reference symbols in these symbols are affected by control channel interference instead of data interference
Solution Approach 1:
The patent applies local quality by recognizing that different OFDM symbols have different interference characteristics. Control symbols in the first three symbols experience control channel interference, while later symbols experience data interference. The patent creates separate interference estimates for different symbol positions and resource element types, preserving these local differences to improve overall estimation accuracy.
Data Source
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AI summary
The present invention relates to a solution for taking into account that the interference, which each of the transmission resource elements is affected by, may differ between the different transmission resource elements when determining an interference estimate by determining a mixed interference estimate, e.g. based on both reference symbols and data symbols. Furthermore, signalling from the network is also introduced which makes it possible to control what the mixed interference estimate should be based on.