An FPGA-Based Implementation of a Multifunction Environment Sensing Device for Shared Access With Rotating Radars

Abstract

To protect radar receivers and to facilitate shared access (SA) in radar bands, regulatory bodies have recommended the use of spectrum monitoring devices called environmental sensing capability (ESC). High-speed and low-cost ESC devices are required to process in real-time the large amount of data (IQ samples) for detection of radar signals and to differentiate them from secondary users (SUs) signals. In this paper, we present a Field Programmable Gate Array (FPGA) based design and implementation of a multifunction ESC device that can detect radar pulses and can also differentiate them from SU signals in microsecond time scales. The proposed ESC device performs the following tasks in parallel: 1) it detects and differentiates between radar and SU signals; 2) measures received signal strength (RSS) from SUs for radar protection; and 3) also measures SUs' airtime utilization (ATU) in a channel which can be used to perform load balancing (based on ATU) of SUs on different channels for efficient access. Detection of signals requires threshold setting. We present a novel minimum-based threshold setting technique which is suitable for real-time operation of energy detectors. We implement a prototype of the proposed ESC device design on a Wireless Open Access Research Platform node which is equipped with a Xilinx FPGA. We evaluate the performance of the implemented device and show that with very high probability (close to 100%) it detects and differentiates between radar and SU signals. Moreover, it also accurately measures the ATU of SUs.

Database-Assisted Distributed and Cloud-Based Access Methods for Unlicensed and Radar Bands

“…Moreover, to provide further protection, a network of sensor devices called environment sensing capability (ESC) is deployed at the boundary of Zone 1. The detailed advantages of deploying ESC near exclusion zone are shown in our work [33]. The ESC is used to detect aggregate received signal strength.…”

“…Practical real time implementation complexity of such airtime estimates are shown in [39]; 2) measurement of total airtime utilization by an AP on its selected channel. In our work [33], we have demonstrated an implementation of airtime measurement module on a Xilinx FPGA. The implemented module takes only a few milliseconds to calculate airtime usage in a channel; 3) calculation of best response updates by the cloud for N APs.…”

A Convolutional Neural Network Approach for Classification of LPWAN Technologies: Sigfox, LoRA and IEEE 802.15.4g

“…However, it incurs huge computation complexity which makes it not suitable for real systems. Using field programmable gate arrays (FPGA), the work in [12] designed and implemented a real-time environment sensing device which can classify between radar and WiFi type signals. However, there are marked differences with our work: a) it focuses on 3.5 GHz and 5 GHz spectrum bands and b) it uses energy detection approaches.…”

Interactive Trial and Error Learning Method for Distributed Channel Bonding: Model, Prototype Implementation, and Evaluation

“…-Channel quality measurements: To obtain quality of other selected channel, the user measures interference plus noise level in that channel. One way to measure interference plus noise level on a channel is to use minimum value processing (MVP) technique presented and prototyped by us in [24]. The MVP technique operates in real-time directly on the energy detection outputs which are an unknown combination of other users signals (interference) and noise of the measured channel.…”