# An Accurate Probabilistic Model for TVWS Identification
## 3 Prototype Description
The GPS information was collected with a BU-353-S4, which is a low power consumption device enclosed in a compact magnetic body, and it can be placed on the vehicle to receive the information of the Global-Sat constellation GPS satellites and save it in our Database (DB). The RFE Sub1G device is a low cost, open source, and portable spectrum analyzer designed for the specific needs of digital radio frequency communication. It supports the detection of expected transmission power, automatic resolution of Resolution Bandwidth (RBW), sweep time, and spectrum data calculations. Moreover, it also has the features of real-time or adjusted signals, 3D spectrogram waterfall, CSV export, and high-quality graphics. A large number of feature sets can be applied and controlled through cooperated work between the RFE and Windows on the Personal Computer (PC) [22]. Two of these RFE devices were used in the M-SSS, one to collect noise samples and another to sense the composite signals, and both readings were sensed in each location. Its technical characteristics are the following:  
* Frequency Range 240 MHz to 960 MHz. * Span 0.112 MHz to 300 MHz. * Frequency Resolution 1 KHz. Figure 4: Mobile Spectrum Sensing Station (M-SSS) designed to be mounted on a vehicle and sense the TV spectrum in wide geographical areas: (**a**) Diagram of the M-SSS; (**b**) Mounted station; (**c**) Winegard and GPS antennas; (**d**) M-SSS in operation. * Average Noise Level \(-115\) dBm. * Amplitude Resolution 0.5 dBm. * Automatic RBW 2.6 KHz to 600 KHz. The Tektronix MD04054-3 SA was used in this project, with the purpose of verifying the accuracy and quality of the readings taken with the RFE, and visualizing the obtained data. It is an oscilloscope with a built-in spectrum analyzer [23], allowing to capture time-correlated analog, digital, and RF signals. Its technical characteristics are:  
* Frequency Range 50 KHz to 3 GHz. * Bandwidth 500 MHz. * Span 1 KHz to 3 GHz. * Frequency Resolution 20 Hz to 10 MHz. * Average Noise Level \(-115\) dBm. * Amplitude Resolution 0.5 dBm. * Automatic RBW 2.6 KHz to 600 KHz. By using the M-SSS, we measured the power level of the UHF-TV spectrum in the city of Windsor, following four trajectories. The samples were taken continuously along the sensed area. The RFE device scans 198 MHz bandwidth of the 500 MHz to 698 MHz UHF-TV spectrum with a separation of 1.76 MHz at a given time instance. This means that there are 198 MHz/1.76 MHz = 112 samples reading per RFE at a given time instance. Along with two RFE devices, we used one GPS device. Hence, a single reading constitutes of 112 Signal power in dBm, 112 Noise power in dBm, and 1 location-timestamp data samples. The RFE devices took readings every 0.340s which implies that for a duration of 1 minute, we had \((112+112+1)\times(60/0.34)\) = 39,705 data samples. The relevant data collection setup parameters are listed in Table 3, which shows that there are 36,176 readings representing 4,051,712 samples per RFE. Since there are 112 samples per reading, in total 8,103,424 samples were collected. The time interval between each reading was 0.340 seconds. The signal and noise data samples, along with the GPS information of Latitude and Longitude, were saved in the DB of the M-SSS.