The first thing people do after an earthquake, small or large, is to meet the need for communication by hugging phones. Today, when news and communication are so important, we have seen how much voice transmission restricts us in GSM with the Istanbul earthquake measuring 5.8 on the Ritcher scale on September 26, 2019 and the Elazig earthquake measuring 6.8 on the Ritcher scale on January 24, 2020.
What is GSM?
Global System for Mobile Communications) global system for mobile communications, or GSM for short, is a mobile communication protocol. All GSM standards use cellular network and are capable of switching between cells even during circulation. Therefore, in theory, if the coverage is not exited, it is possible to travel the whole world without disconnecting from the mobile phone.
GSM Band Ranges
In the GSM900 protocol, the frequency between 890-915 MHz is called UpLink and the frequencies between 935-960 MHz are also used for the so-called DownLink. Since the carriers have a frequency of 200 kHz, it allows the use of 124 carriers.The 2 MHz portion between 915-917 MHz is left for the protection tape. This 2 MHz protection band was created to prevent interference (distortion) between electromagnetic waves between shopping frequencies.
Since the carrying capacity is higher, it is often used in areas with high urbanization. Frequencies between 1710 and 1785 MHz are used for uplink and bands between 1805 and 1880 MHz are also used for downlink. Carriers are used at 200 kHz intervals and there are 374 carriers.Between 1785 and 1805 MHz frequencies, the 20 MHz protection band prevents deterioration.
Since the carrying capacity is higher, it is often used in areas with high urbanization. Currently, it is only used in the United States.
124 frequencies are used in gsm900 band. Up to 7 people can speak at a frequency with the Time Division Multiplexing method. Accordingly, if all frequencies are used, up to 7X124=868 people can speak within the coverage area (considering nationwide coverage) at the same time. This number is very insufficient considering the population of Turkey. Cell structure is designed due to the limited frequency and high need. In the cellular system, the same frequency cannot be used in neighboring cells. However, since there are no other restrictions, the same frequency can be used many times in different cells around the world. The number of frequencies to be given to the cells is determined by the subscriber density in the cell. Each cell covers a specific area, and each cell has a main transceiver station and antenna that allows connection with the mobile device. All phone calls within this area take place through this antenna and station. The central operator regulates the traffic of all phone calls and also provides its connection to the landline.
Audio Transfer with Alternative Data to Voice Communication
We are talking about the fact that the capacity of GSM operators will push the boundaries but will never be enough, but in fact, if the way of online negotiations had been opened, a much greater number of calls could have been made by voice today. Let's talk about companies that will serve with a phone device that transmits audio over the mobile internet (similar to voice calls made via WhatsApp). As you know, online conversations reduce the GSM operator's audio revenues. Serving from WhatsApp-like platforms began in the 2000s by providing voice over the internet. This has been mentioned many times by NGOs and newspapers, but BTK has been fixed since the early 2000s(VoIP)and after 2013 has blocked audio over the internet via mobile devices. When WhatsApp starts with text messaging and starts to give voice after 2015, it was not blocked because the community would react, but when a company from Istanbul (or another city) wants to give this service with a mobile device, this obstacle will be faced, so as long as BTK removes this decision, this technology will still be far away from us. In other words, we may not have problems with voice communication in the earthquakes in Istanbul and Elazig. Or we could have lived less. But let's also remember that starting a conversation with BTK via mobile handheld devices is a decision taken in favor of GSM operators but against the consumer.
Communication in an Earthquake
Under the current circumstances, in the event of an earthquake, when everyone is wrapped in phones, capacity is instilled and the system is locked. No matter how much the GSM System develops, as soon as the frequency range ends, problems start to appear, let's give an information about the earthquake we experienced in Istanbul and Elazig; "there were no cell towers that went out of line." It was only in the time after the earthquake that there were over-capacity phone calls. The reason is the communication traffic that intensifies at the time of the earthquake, as well as those who call earthquake zones from abroad. At this point, let's convey a note that we should all pay attention to; When there are earthquakes or other disasters, it is important for us, not the citizens, to communicate with the authorities. Therefore, with today's communication infrastructure, it is necessary to use phones with little and no essence in the event of an earthquake, considering both the needs of others and the needs of these officials. Therefore, if it is not very urgent in disaster situations, calls should not be made over the phone, such as WhatsApp. Or we should communicate with the correct text messages (SMS).
How Do Two GSM Lines Communicate?
Cell towers and mobile phones are constantly connected. You can tell by the signal strength indicator on the mobile phone. When you call a contact, the call signal from the base station to the switching center and then to the data center connects to the cell tower of the caller and transmits your call signal to that phone. When the other party picks up the phone, the connection is established. During the time you make your call, it allows you to exchange data with cell towers on both phones. Meanwhile, in order to ensure data security, the communication frequency changes dozens of times at the time of the interview with a modulation method called CDM (Code Division Modulation). Cell phones and cell towers synchronously change this frequency. Before I forget, cell phones communicate using electromagnetic waves. There are two different frequencies for wireless communication in Turkey: GSM900 and DCS1800.GSM is divided into three main groups according to its coverage area. Of these, they serve for an area of macro GSM 25 – 30 km radius. They are usually used in small settlements. Micro GSM airports are used where a communication network of several hundred meters is required, such as large shopping malls. Piko GSM is a small system that is usually used in structures such as in-building buildings.
Mini Earthquake Guide
We love to make our readers aware of many things, in addition to this article we have put this "Earthquake Guide", I hope that you will find answers to the basic questions, "disaster does not kill, neglect kills".
What to Do Instantly in an Earthquake
As well as preparing a disaster bag before an earthquake, it is very important to apply the "triangle of life" in the event of an earthquake. You should lie in a fetal position next to a stationary and intact object in your environment, protect your head with your hands or hold on to the solid object to wait for the earthquake to end. As soon as you are sure that the earthquake is over, close the gas and water valves and lower the electrical specifications. If you can't afford it, turn off all electrical, gas-powered appliances near you. Then take your security precautions and proceed to the meeting area without leaving anyone behind in your environment with your earthquake bag. When leaving the environment, proceed away from all objects made of glass, not fixed. Leave your location without using an elevator. And contact the nearest authorities. If there are objects or obstacles that prevent you from leaving your environment, assess the situation without panicking. Cautiously review your survival standards, and wait for the nearest help to arrive. Using sound-emitting objects (whistles) while waiting for help will increase your chances of being rescued. For example, the triangles of life in a dilapidated building
Communication at the Time of an Earthquake
GSM Operators; Telephone operators have a certain communication capacity. When this capacity is exceeded, it causes the network to collapse, which leads to our ability to communicate. Messaging Apps; You can easily choose messaging applications used with internet connection during and after earthquakes at the intensity of cell towers. Your Internet Package; Since we do not know when we will encounter an earthquake big enough to have problems with communication, we can use our internet package without problems at the necessary times by checking our internet package frequently. Your phoneis a modem; You can turn your phone into a modem by opening your phone's personal access point to people like you who want to communicate during and after an earthquake and cannot do so because there is no internet package. Internet-Free Messaging; Even if it is not in every earthquake, internet connections may also encounter problems. Having apps available on your phone without the Internet and via Bluetooth can be useful for such situations.
Internet-Free Messaging Apps
Applications where you can communicate directly with the other person via your phone's Bluetooth and WiFi antenna, in reference to cell towers that become obsolete in natural disasters;
An application that works with the multipeer connectivity framework infrastructure, serves as a transfer station for mobile phones in areas without GSM base stations or wireless networks, and theoretically provides chained messages and data transmission over Wi-Fi or Bluetooth as long as there is a mobile phone at an accessible distance. In short, with one-on-one phones, no matter how far away the target is, your messages will reach the destination as long as the connection is made. App Store Play Store
FireChatin bears similarities to the infrastructure it uses. Honk Kong has become a very popular app these days because it is used quite a lot in its shows. The same distance and logic is at stake in this application. App Store Play Store
Investigate the earthquake hazard status of your place of residence. Avoid unnecessary panic in the event of an earthquake and inform the people around you that there is an earthquake. Find a place you think is safe – get down on your knees – wait until you're sure the tremor has passed in a position to protect your head. If you're in the car, pull the car over a wide area and wait inside the car until the earthquake is over. Stay away from dangerous things in the outer space, such as bridges, underpasses, trees, poles and power lines. Aftershocks are possible after major earthquakes. Be prepared for aftershocks.