Abstract
Digital beamforming is the holy grail of antenna array technologies, however implementing digital beamforming into practical antenna arrays has been slow due to hardware complexity and cost. We propose a relatively inexpensive new approach to digital beamforming using software defined radios. Using this system, we carried out experiments on adaptive interference cancellation. We present detailed description of the beamformer system along with the developed control software and experimentally verify the beamformer performance. Our results show that in high-interference and high-multipath environments, where carrier frequency offsets cannot be measured, conventional interference cancellation algorithms fail. We propose two new robust solutions to this problem and compare the results with multiple techniques, including the minimum variance distortionless response beamformer, which outputs the highest possible signal-to-interference-plus-noise-ratio (SINR). We experimentally demonstrate that both our approaches work well in the face of these types of signal corruptions and are capable of interference cancellation without degrading SINR or other system performance factors, and without the need for transmitter and receiver synchronization.
Highlights
Our wireless infrastructure and the spread of the Internet of Things (IoT) unleashed billions of radio-frequency (RF) devices that fill the allotted spectrum with signals
New interference cancellation algorithms that can operate without the need for synchronization are given in Section V where we demonstrate the robustness of these techniques in a realistic high-multipath environment
We present two new adaptive nulling approaches that are robust to carrier frequency offset, i.e., they operate without the need to synchronize the transmitter and receiver
Summary
Our wireless infrastructure and the spread of the Internet of Things (IoT) unleashed billions of radio-frequency (RF) devices that fill the allotted spectrum with signals. Signal processing and optimization algorithms modify the element weights to enhance signal detection [3]-[6] These arrays dramatically improve performance in hostile radio environments, but their very high cost limits implementation on a wide scale, for civilian applications. The primary goals of this research are to, (1) build a lowcost platform for robust DBF using an array of SDRs, and (2) experimentally study the interference cancellation capability of the system in a realistic high-multipath environment. New interference cancellation algorithms that can operate without the need for synchronization are given in Section V where we demonstrate the robustness of these techniques in a realistic high-multipath environment.
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