# Real-Time Statistical Measurement of Wideband Signals Based on Software Defined Radio Technology
## 3 Materials and Methods  
### Hardware Configuration  
The goal of this work is to develop an affordable measurement system that can effectively replace a high-performance SA in performing advanced signal statistical measurements. To evaluate the capabilities of the system, we followed a methodology that involved first generating reference signals using a signal generator and then performing tests with real signals to simulate different scenarios. The performance of the system was then evaluated by comparing the results with measurements obtained using a SA with real-time capabilities. This comparison method was used to validate the accuracy and reliability of the measurement system results compared to the established spectral analyzer.  
In order for a monitoring station to qualify as real-time, it must capture IQ components in the baseband or intermediate frequency (IF) range and then perform processing on these components. This allows complex analysis of the electromagnetic spectrum (amplitude analysis and phase analysis). SDR platforms are designed to enable flexible and programmable radio systems using software-based signal processing techniques. In the case of SDR technology, the acquisition bandwidth is dependent on the sampling frequency (the channel bandwidth is given by the sampling frequency).  
To ensure real-time measurement capability and high flexibility in the development of the monitoring system, the main starting point was to use the Universal Software Radio Peripheral (USRP)--an SDR platform from Ettus Research--together with the GNU Radio Companion software, upgraded with some custom blocks developed in Python scripts. Based on this concept, a computer was assembled with the Linux operating system (Ubuntu 20.04) and GNU Radio installed. The USRP X310 was also chosen as the SDR platform, with a UBK 10-6000 MHz Rx/Tx receiver board with a full-duplex wideband transceiver and an instantaneous bandwidth of up to 160 MHz. The main features of this SDR are shown in Table 1[36].  
The connection between the computer and the SDR was made over multimode fiber using a GbE SFP+ with two 10 Gbps ports to provide up to 10 Gbps transmission speeds with low interference (Figure 1). The computer was equipped with an eighth-generation Intel(r) Core(tm) Pro i7 processor and 32 GB of RAM, with an additional 2 TB PCIe 4.0 NVMe solid state drive (SSD) for I and Q data recording capabilities at 160 MHz bandwidth (2 \(\times\) 16 bits \(\times\) 160 MS/s = 5.12 Gbps).  
In parallel to this work, another system made of a signal generator and spectrum analyzer was set up to serve as a reference system for the parameterization and testing of the prototype system. The reference system consists of two Rohde and Schwarz instruments: SMM100A signal generator and FSVR7 real-time spectrum analyzer with channel power and CCDF capability and a laptop for SciPy control.  
The parameterization and testing of the proposed system were first performed under laboratory conditions, where the IEEE 802.11 ax signals were provided by a vector signal generator. Following the controlled environment, the measurement system was used in an uncontrolled environment, in an over-the-air measurement campaign for signals emitted in the 4G/5G and Wi-Fi 6 communication standards.