Wireless Communication System Adaptive Channel Estimation
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Solution Overview
Problem
Conventional wireless communication systems face challenges in maintaining accurate channel estimation and interference removal performance, especially when mobile stations move at high speeds, leading to decreased accuracy and interference removal efficiency.
Innovation Solution
The system employs an average time parameter based on the mobile station's speed to improve channel estimation accuracy, using different known sequences for each base station to enable effective interference signal extraction and removal without requiring system shutdowns, allowing continuous monitoring of co-channel interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel estimation is performed using conventional methods, then the system can operate continuously without shutdown, but the accuracy of channel estimation and interference removal decreases when mobile station moves at high speed
Solution Approach 1:
The patent applies dynamics by making the averaging time parameter adaptive based on mobile station speed. The system dynamically adjusts the parameter L (averaging time) according to the detected speed of the mobile station, using longer averaging times for high-speed movement and shorter times for low-speed movement. This dynamic adaptation resolves the contradiction by optimizing channel estimation accuracy for each speed condition without requiring system shutdown.
Solution Approach 2:
The patent changes the parameter L (averaging time) based on mobile station speed to improve channel estimation accuracy. By modifying this key parameter according to operational conditions (speed), the system maintains estimation precision across varying speeds. The parameter is adjusted within the range of 1 to 100 based on speed measurements, directly addressing the accuracy-speed contradiction.
2Productivity
If the system uses the same frequency for multiple base stations, then frequency utilization efficiency improves, but co-channel interference occurs between base stations
Solution Approach 1:
The patent converts the harmful interference signal into a useful component for estimation. By using the interference signal itself (along with the desired signal) to perform channel estimation and generate weights for interference removal, the system transforms the harmful co-channel interference into a basis for improving reception quality. This allows frequent reuse of the same frequency while maintaining communication quality.
Solution Approach 2:
The patent implements feedback by using the estimated channel information and interference characteristics to calculate optimal weights, which are then applied to remove interference from the received signal. The system continuously estimates interference based on received signals, adjusts weights accordingly, and applies them for signal restoration, creating a closed-loop feedback mechanism that enables effective frequency reuse despite interference.
3Measurement precision
If blind-type weight calculation algorithm is used, then optimization processing can be performed, but the complexity of the calculation increases
Solution Approach 1:
The patent applies preliminary action by performing channel estimation using available received signals and known sequences before the actual interference removal process. By pre-calculating channel estimates and using them to determine weights in advance, the system simplifies the subsequent interference removal operation. This preliminary estimation step reduces the overall computational complexity while maintaining interference removal effectiveness.
Data Source
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AI summary
A wireless communication system (1) includes: base stations (10-1, 10-2) that are a plurality of transmission devices that transmits signals including different known sequences using a same frequency; and a mobile station (20) that is a reception device that performs channel estimation using a reception signal received from at least one of the plurality of transmission devices, an average time parameter, and at least one of a plurality of the known sequences corresponding to the plurality of transmission devices, and removes an interference signal included in the reception signal using a result of the channel estimation, the average time parameter being a parameter related to channel estimation accuracy and determined based on a moving speed of a moving one of the reception device that receives the reception signal and the transmission devices that transmits the reception signal.