Jurnal Jaringan Telekomunikasi E-ISSN: 2654-6531 P- ISSN: 2407-0807 Vol. 12, No.1 (2022) 26-31 26 Utilization of RSSI on Visitor's Cellphones in Calculating Distance to Wifi Transmitter in the Reading Room of the State Polytechnic of Malang Library Monica Wahyuni 1 , Mila Kusumawardani 2 , Rachmad Saptono 3 1,3 Program Study of Digital Telecommunication Networks Department of Electrical Engineering, State Polytechnic of Malang, Malang, 65141, Indonesia 2 Program Study of Telecommunication Engineering Department of Electrical Engineering, State Polytechnic of Malang, Malang, 65141, Indonesia 1 1741160061@student.polinema.ac.id, 2 mila.kusumawardani@polinema.ac.id, 3 rachmad.saptono@polinema.ac.id Abstract—The pandemic period caused by the coronavirus disease causes restrictions on the number of users in a room to minimize the spread, for example, libraries. The library is a room area that can cause virus transmission when crowds of visitors. A system is needed to provide information regarding the number of library visitors. Utilizing a network (wifi transmitter) available in the library can provide information on the number of visitors based on the number of network users in a room. Utilization of the network (wifi transmitter) can be in the form of a positioning system by utilizing the wifi signal beam received by the user in RSSI (Received Signal Strength Indicator). To calculate the estimated user position, a trilateration method is used based on the placement of three wifi transmitters. The library visitor positioning system consists of users as wifi transmitter users and admins. At the X-coordinate, the measuring point with a low deviation of the measurement value is indicated by points C and E with a value of 0.1. The large deviation of the measurement value is indicated by the P point of 4.5. At the Y coordinate, point O has a low deviation value of 1.25, and the largest deviation value is at point M of 5.6. The accuracy of the X coordinate shows a value of 97.647% and at the Y coordinate of 96.57%. Both coordinates have good accuracy for the points used as position measurements. Keywords—WIFI transmitter, Positioning, Received-signal-strength-indicator, Libraries, Network. I. INTRODUCTION The pandemic period caused by the coronavirus disease causes a room to be limited in the number of users. The room that can be a concrete example at this time is the library. The library is a room area that can cause virus transmission when crowds of visitors. We need a system that can provide information related to the position and the number of visitors to the library. Wireless network technology has an important role in making a system that can provide appropriate information during the pandemic era. The utilization of wireless network technology and communication media can also be used as an estimation medium for determining the location of an object [1]. Determining the location of an object is also known as the concept of indoor localization. Indoor localization uses a lot of Wireless Local Area Network (WLAN) technology because WLAN/wifi is almost available anywhere and can be integrated with smartphones easily[2], [3]. One of the pieces of information from wifi that can be used in indoor localization is RSSI (Received Signal Strength Indicator). RSSI works by measuring the signal strength of packets at the receiver. RSSI is often used to find the distance between transmitter and receivers [4]. Thus, the wireless network (wifi transmitter) can show user intensity based on RSSI reception, calculated using an integrated application on the library's wifi transmitter user's cell phone. Calculations are carried out on the application on the visitor's cellphone running on the Android operating system [5]. The calculation result is the distance between the user and the wifi transmitter. The main parameter of the position estimation calculation is RSSI [2], [6], [7]. A trilateration method calculates the estimated user position on the wifi transmitter. The trilateration method is commonly used to determine the estimated position of an object in the room. This method looks for position estimates based on references with a minimum of 3 references. The trilateration method has two important components in predicting position: distance and transmitter position. The distance can be calculated by taking the average signal strength value obtained. Users connected to the wifi transmitter will be visualized in the form of a wind speed chart on each user's cellphone [8]. II. LITERATURE REVIEW A. Trilateration. Trilateration is a method or algorithm to determine the position of an object (smartphone) based on simultaneous distance measurements from 3 access points located around the location. The position of the object (smartphone) can be. For example, the coordinates (x, y) can be detected by measuring the object's distance (smartphone) from the three access points. The basic principles of trilateration are: ( - ) 2 + ( - ) 2 =  2 ( = 1,2,3) (1)