Smart Antenna Beamforming Device DOA Estimation
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Solution Overview
Problem
In mobile communication systems, existing technologies face challenges in separating desired signals from interference signals due to multiple interference sources and obstacles, leading to communication distortion and difficulty in estimating Direction Of Arrival (DOA), which affects signal identification and beamforming efficiency.
Innovation Solution
A smart antenna beamforming device and method that estimates DOAs of received signals, identifies desired and interference signals, generates beamforming vectors using an interference-plus-noise covariance matrix, and performs maximal ratio combining to form effective beams, thereby enhancing signal-to-interference ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DOA estimation is performed after coherent demodulation in array antenna elements, then signal processing can be performed, but when base station receives desired signal from various angles due to neighboring obstacles, it is difficult to separate the DOAs from various paths and angular diversity cannot be obtained
Solution Approach 1:
The antenna array is divided into two sub-arrays that are spaced sufficiently apart from each other. This segmentation allows the system to receive signals from multiple directions and perform adaptive beamforming on each sub-array independently, thereby obtaining spatial diversity and angular diversity that were not achievable with a single unified array.
Solution Approach 2:
The patent introduces a spatial dimension by spacing the two sub-arrays apart from each other. This physical separation in space creates additional spatial diversity, allowing the system to distinguish between signals arriving from different angles and paths, thereby resolving the limitation of conventional single-array DOA estimation.
2Reliability
If reference signal is transmitted in every subcarrier to estimate covariance matrix, then adaptive beamforming can be performed, but it takes a long time to estimate the covariance matrix
Solution Approach 1:
The patent performs preliminary DOA estimation using data subcarriers before the main beamforming operation. By pre-estimating the DOAs and identifying desired versus interference signals in advance, the system reduces the computational burden during covariance matrix estimation and accelerates the overall beamforming process while maintaining accuracy.
Solution Approach 2:
The patent extracts only the necessary information (DOAs of desired and interference signals) from the received signals using data subcarriers, rather than processing all subcarriers equally. This selective extraction of critical parameters reduces the time required for covariance matrix estimation while preserving beamforming reliability.
3Adaptability or versatility
If entire antenna array is formed by two sub-arrays spaced sufficiently apart, then spatial diversity may be obtained, but it is difficult to identify the desired signal and the interference signal by the base station
Solution Approach 1:
The patent performs preliminary signal identification by estimating DOAs of all received signals using data subcarriers before combining signals. By identifying which signals are desired and which are interference based on their DOAs in advance, the system resolves the difficulty of signal identification that arises from using multiple spaced sub-arrays for spatial diversity.
Data Source
AI summary
A beamforming device includes a Direction Of Arrival (DOA) estimation unit for estimating DOAs of the received signals based on a data subcarrier matrix; a pre-spatial filtering unit for using the estimated DOA, performing a filtering operation for the data subcarrier matrix, and generating filtering matrixes; a signal identification unit for using a data sequence, identifying original and interference signals, and generating the DOAs of the original and interference signals; a spatial filtering unit for generating an interference-plus-noise covariance matrix by using the DOA of the interference signal, eliminating the interference signal by using the covariance matrix and the DOA of the original signal, and forming final beams for the original signal; and a channel estimating and signal combining unit for performing a maximal ratio combining operation so that the final beams are combined as one combined final beam.