# Real-Time Statistical Measurement of Wideband Signals Based on Software Defined Radio Technology
## 1 Introduction
However, 4G and beyond technologies need customized electromagnetic measurement platforms capable of providing complete signal characterization, including statistical analysis of the temporal evolution of the PAPR. This identified technological limitation is to be addressed in this paper. Although 4G is currently the most widely deployed mobile technology, a new generation of internationally standardized technologies has the potential to completely transform mobile communications [12]. The fifth generation (5G) wireless network, called New Radio (NR), has been developed to provide ultra-reliable low-latency communications (URLLC), much higher data transmission speeds (about 100 times faster than 4G), massive MIMO, enhanced mobile broadband communications, millimeter-wave communications, and massive machine-to-machine communications (mMTC) for implementing Internet of Things services and applications [13; 14]. Unlike 4G, which uses frequencies below 6 GHz, 5G NR uses both frequency band 1 (FR1) between 450 MHz and 7125 MHz and FR2, also known as the millimeter wave band, between 24 GHz and 50 GHz. Depending on the frequency range, the bandwidths vary, so the maximum achievable bandwidth for FR1 is 100 MHz and for FR2 it is 400 MHz [15]. The Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) channel resource access technique for 5G NR [16] is similar to OFDM in LTE, except that the subcarrier spacing is no longer 15 kHz, but a variable subcarrier spacing is used, which implicitly also changes the cyclic prefix duration per symbol. Statistics show that over the past few years, 50% of Internet traffic is carried by LTE, with the other half carried by Wi-Fi [17]. The capacity of Wi-Fi networks has been significantly improved with the release of IEEE 802.11 ax, which aims to improve spectral efficiency and end-user throughput in densely deployed Wi-Fi environments. OFDMA is the radio access scheme implemented by the Wi-Fi 6 (802.11 ax) standard to enable efficient use and allocation of spectrum, reduce transmission latency, improve power spectral density, and enhance the overall user experience. OFDMA provides performance by dividing the channel or available 20/40/80/160 (80 + 80) MHz frequency bands into hundreds of subchannels, allowing devices such as access points to transmit data to multiple stations simultaneously and vice versa. Sixth generation Wi-Fi (IEEE 802.11 ax) supports up to 74 users at 160 MHz channel bandwidth, 37 users at 80 MHz, 18 users at 40 MHz and 9 users at 20 MHz for the mentioned bandwidths in the 5 GHz band [18; 19]. In summary, both cellular and wireless communication standards have diversified and evolved to meet the increasing user demands. Today, the electromagnetic spectrum is occupied with communication channels of variable bandwidths: 5 MHz (3G), 20 MHz (4G, 3 rd generation Wi-Fi), 100 MHz (5G), 160 MHz (IEEE 802.11 ax); radio access techniques have diversified, digital modulation methods have improved, and smart antennas have changed the communication quality paradigm by using MU-MIMO and beamforming techniques. The complexity of modern communication channels poses challenges for efficient spectrum measurement and monitoring. To address these challenges, there is a need to fill this technological gap and identify an agile measurement solution that can provide real-time information about the spectrum together with the implementation of advanced electromagnetic spectrum measurement capabilities. This issue is further detailed in the next section of the paper, where we provide a detailed discussion of advanced spectrum measurement capabilities.