GPON TECHNOLOGY AND ITS SPECIFICATIONS

M.A. Ruziqulova

Assistant of the Department of Software Engineering Karshi branch of the Tashkent University of Information Technologies named after Muhammad al-Khwarizmi, Karshi

N.E. Negmatova

Student 2^nd course

Tashkent University of Information Technologies named after Muhammad al-Khwarizmi

Annotation: The article presents the GPON technology. GPON technology - Gigabit Passive Optical Network - is a passive optical network, thanks to which the provider can provide high-speed Internet access at speeds up to 1 Gigabit per second.

Keywords: GPON, GEPON, ONT, PON.

Today, there are several different ways to connect to the Internet. Conventionally, they can be divided into wired and wireless. GPON technology is the most modern wired Internet access technology, which is actively promoted by the largest providers of Uzbekistan - Uztelecom. GPON or Gigabit PON technology has been introduced relatively recently. Let's figure out what became the prerequisites for the emergence of GPON technology, what prospects it has, and also compare it with competing technologies - PON and GEPON. 2014 will mark the 45th anniversary of the first computer communication session conducted in the United States at a distance of about 640 km. This event is considered the beginning of the birth of the Internet. In the first decade of the development of the global network, among users who paid attention to such an indicator as “communication channel capacity (data transfer rate in bits)” or the characteristic “bandwidth” associated with it, there were “a few units” of people familiar with the theoretical foundations of radio engineering . And today everyone talks about “speeds on the Internet”. And everyone wants to have "high-speed Internet" at their disposal. Why High Speed? And where is the limit from which Internet access can be considered "high-speed"? For a mass user, the speed of the Internet is associated, first of all, with the time intervals for downloading “heavy” video, music and graphic files, the number of which on the Web is growing exponentially, and they themselves are “enlarged”. Corporate consumers of online services (and more recently also "cloud") need a high speed of response to requests in the used business management systems. This means that high-speed Internet is an urgent need, not a whim (both for "users" and for companies). The "border" from which high-speed Internet begins, today, according to experts, is at the level of 10 Mb / s.

The worldwide computer network began to develop on the basis of existing telephone lines using xDSL technologies. The most "advanced" version of this "copper" family - ADSL2 + modem technology provides an incoming stream speed of 24 Mb / s (outgoing - 1.2 Mb / s). Currently, it is the undisputed leader in terms of the number of connections in all countries of the world. However, "copper" communication lines, laid decades ago, are becoming obsolete both physically and morally and are gradually being replaced by FTTx optical networks, the use of which makes it possible to increase the speed of information exchange on the Internet by two orders of magnitude. And in the near future, even more.

In the last five years, the process of replacing copper cable routes with optical ones has been growing and, according to analysts, in another five years the ratio of "optics / copper" in telecommunications will change dramatically in favor of "optics". The FTTx (Fiber to the x) architecture is a segment of a fiber optic communication line connected on one side to the transceiver station OLT (Optical Line Terminal - optical line terminal) installed at the operator, and on the other hand to the transceiver modules of subscribers - ONT (Optical Network Terminal) or ONU (Optical Network Unit). ONT - a terminal for individual use (it is also called an optical modem) installed in an apartment. ONU - designed to be installed in the distribution cabinet of an apartment building and has several ports for connecting computers, TVs, telephones located in neighboring apartments. ONT and ONU convert the optical signals received from the OLT into electrical ones (sent, for example, to computers, TVs, telephones), and also perform the inverse conversion of electrical signals received from the user terminals into optical ones, which are sent to the OLT. If splitters (passive splitters of the signal coming from the OLT) are introduced into the segment of the optical line and ONT is connected to their outputs, then such a transition from a single-fiber FTTx structure to a tree structure will lead to the formation of a passive optical network - PON (Passive Optical Network).

The work of PON is to organize multiple access through a single fiber through time division multiplexing (Time Division Multiplexing Access - TDMA) and frequency division of the receive and transmit paths (Wavelength-Division Multiplexing - WDM). WDM multiplexers operating as part of OLT and ONT separate direct (incoming) and reverse (outgoing) signals broadcast at different wavelengths (direct - 1.49 µm, reverse - 1.31 µm). These streams can be supplemented with a cable television signal transmitted at a wavelength of 1.55 microns. The first sprouts of PON technologies appeared about 15 years ago, and since then the International Telecommunication Union (IEC) has released five standards for data transmission over optical fiber. Active equipment manufactured in accordance with the requirements of these standards provides speeds from 155 Mb / s to 2488 Mb / s. The features of these standards will be discussed below, but for now we emphasize that the advantages common to all types of PON technologies are the ability to easily increase the subscriber base, maintain and upgrade it, as well as low (compared to "copper" technologies) operating costs. The channel is symmetrical, that is, the speeds of the incoming and outgoing channels are equal. The topology of the GPON network resembles a tree, where passive splitters are placed on the nodes - splitters.

         At the same time, a fiber optic cable is connected directly to the subscriber’s apartment or private house, an optical socket is installed and a GPON terminal is connected, which is usually called an “optical modem” by the people. It looks almost the same as a regular WiFi router, with the only exception that it does not use an Ethernet connector as an external WAN port, but an optical port (usually of the SC standard). Due to the huge channel bandwidth for a regular client, the provider has the opportunity to provide the subscriber with all available services at once: - Home Internet at speeds up to 1Gbit / s; - Digital interactive television (including HD content); - SIP phone; - CCTV; - Security and fire alarm. What equipment is needed to connect GPON? On the part of the subscriber, an ONT optical modem is installed - this is a special router that has an optical connector as an Uplink port and is designed to transmit data over an optical fiber.

Otherwise, this is a regular router with a WiFi module, to which you can connect a home computer, laptop, TV, tablet or mobile phone. The device usually has four Ethernet ports, two FXS ports for connecting telephone sets, and a connector for connecting an optical cable. To date, the most common modems for GPON technology are devices from the following manufacturers: - Huawei (HG8245, HG8247) - ZTE (ZXHN F660) - Eltex (NTP-RG-1402GC-W, NTU-2V) - SERCOM (RV6699, RV6688BCM) In terms of the quality of work, the best is the equipment of the Chinese company Huawei. Everything else is of lower quality with all the ensuing consequences.

REFERENCES

Usedelectronicresources:

1.     http://archive.uzonline.uz/ru/services/gpon/

2.     https://ru.sputniknews-uz.com/society/20151209/1269433.html

3.     http://nastroisam.ru/tehnologiya-gpon-fiber-network/

4.     https://skomplekt.com/technology/gpon_tehnologiya.htm