In this article we will try to explain the operating principle of the DAS system installed and used in the tourist center of Samarkand. DAS (Distributed Antenna System) is a distributed antenna system. DAS is used in a variety of public and social institutions, including business centers, airports, universities, stadiums and hospitals. DAS is very useful in providing quality mobile communications and internet in these regions. DAS is also used to improve telephone service, expand the Internet, and improve audio quality.
DAS is defined as a converged single transmission medium connecting spatially dispersed antennas that provide wireless access to users within a structure or area. Convergence is the property of a system, roughly speaking, to transmit voice, data, etc. over one cable. DAS can be designed to support multiple providers at once, gaining the ability to work in different frequency bands and with different technologies.
The DAS system consists of :
There are three types of DAS:
• Passive
• Active
• Hybrid
Passive DAS
Uses coaxial cable to transmit a signal to each floor of a building (the area needing coverage). Consists of various types of passive elements: couplers, splitters and dividers. These passive elements “take a portion” of the signal to each floor, the distribution of the total signal power is calculated by engineers, and the passive elements are selected in accordance with these calculations. Passive DAS has no active electronic components.
Active DAS
The radio signal at the equipment input is converted into an optical signal. This process takes place at the central control unit or at the base transceiver station. The signal is transmitted via optical fiber to internal active antennas with a built-in remote control unit.
Hybrid DAS
Hybrid DAS is a combined approach to expanding mobile network coverage. Combines active and passive DAS. This system combines several technologies and data transmission methods to optimize communications in various environments. Hybrid DAS can use both wired and wireless antennas to provide wide coverage and improve the quality of mobile communications. It supports various communication technologies, such as GSM, CDMA, LTE, 5G, Wi-Fi and others, which allows for multifunctionality and flexibility in use. Hybrid DAS can be integrated with external networks such as cellular networks or ISPs to ensure quality of service.
Installers of the DAS system Appendix 2 to the Resolution of the Cabinet of Ministers of the Republic of Uzbekistan dated December 22, 2020 No. 801 in accordance with Chapter 5 of Article 56 of the Regulation “On the procedure for acquisition (issuance) and (or) installation (construction), import, issuance of permits for the use of radio-electronic equipment and high-frequency devices” permission to use a mobile base station for mobile communications in radio frequency bands allocated to mobile operators for the purpose of organizing communications within no more than 500 mW of effective power of isotropic radiation, while before the start of construction and installation work of a mobile base station for mobile communications, the user of the radio frequency spectrum within ten working days, information about the installation location and main technical parameters is provided to CEMC in the form of a notification.
Currently, large hotels, the Congress Hall Palace and other buildings of the tourist center of Samarkand are provided with high-quality mobile communications and mobile Internet using an active DAS system. As a result, foreign and domestic tourists visiting the Samarkand tourist center had the opportunity to use high-quality mobile communications.
Prepared by: category 1 engineers of SEMC of the Samarkand region Olmasov A.A. and Urazov A.A.
