Actual problems of modern science, education and training

Analysis and results. Each of the presented types of network is designed to solve a certain type of problem in a certain field of activity. Over time, this area has constantly expanded and IoT technologies have become popular. When choosing a particular technology, you will need to choose priority opportunities. It is possible to combine these features of these networks for the best effect.
Railway transport has its own specifics, since the industry as a system has its own subsystems, and individual requirements are also different. For example, it is convenient to use cellular networks for geolocation of locomotives in the city, but not in distant parts of the country. This is due to the placement of antennas of cellular enterprises.
The wagon, unlike the locomotive, does not have an autonomous power supply and there is also more critical information regarding the wagons. When choosing types of communication, we should include among the priority opportunities: energy efficiency - the ability of sensors to work for a long time; range - for remote control; costs for installation and operation.
LPWAN becomes the best option, which can provide dispatch personnel with information for making decisions on traffic management. The next step in the selection is the selection of a specific type of network related to LPWAN. LPWAN includes wireless networks: LoRaWAN, Sigfox and NB - IoT.


Power consumption

Data rate
Low

Low ^Range High

Figure. 2. Diagram comparing wireless types of communication

It should be weighed from the point of view of the specifics of rail transport management. Let 's do a SWOT analysis to better understand the network's strengths and weaknesses.
LoRaWAN or Long Range Wide Area Network was introduced as an energy efficient network technology by IBM Research and Semtech . Technology based on Semtech LoRa (™) PHY chip [2]. In terms of technical capabilities, it can satisfy the requirements for information support in transportation processes. The main advantages include low power consumption, relatively inexpensive deployment cost and availability, autonomous ownership of the entire infrastructure (independent of cellular networks) and a wide range of applications (Fig. 3).


Figure.3 - SWOT analysis of the Lorawan wireless network
SigFox is built by the company of the same name, founded in France in 2009. It uses Ultra Narrow Band (UNB) technology, the same technology used for submarine- to-submarine communications during World War II [2]. This technology was originally designed for communication at low data rates. The main advantages of the system are ultra-low power consumption, low cost. It should be noted that the principle of operation is almost the same as LoRaWAN , but the technical capabilities and the level of global coverage are different (Fig. 4).




SigFOX

Strengths
Ultra-low power consumption,
low cost
Weaknesses


Low data transfer rate, level

Opportunities
Long range, flexibility in terms of installation
Threats


Limited noise immunity

LoRaWAN

Figure 4 - SWOT analysis of the SIGFOX wireless network

NB - IoT is purpose-built for the IoT, so it takes into account specific needs such as improved sensitivity to signal modulation to connect hundreds of thousands of devices. Also, to work with NB - IoT , you do not need a SIM card and a fairly low power of the transceiver, that is, IoT devices can work for many years from one battery. The strong side is the large bandwidth and data security (Fig. 5).

Strengths
High bandwidth, data
security
Weaknesses
Requires a license, high cost of operation

Opportunities
High-quality data transmission in urban
conditions
Threats
Dependence on cellular companies

Figure.5 - SWOT analysis of the wireless network NB - IOT

According to specific features, you can choose one or another system. To manage the transportation process on the railway, you should choose the LoRaWAN system. Here are the reasons for this choice:

1. 
   LoRaWAN has no limit on the number of messages sent per day, compared to SigFox which can send 140 messages per day.
   
2. 
   LoRaWAN has a larger payload size (payload) of 100 bytes compared to SigFox which has only 12 bytes.
   
3. 
   LoRaWAN has open LoRa Alliance with global public network coverage. Compared to SigFox, a significantly larger coverage area.
   
4. 
   LoRaWAN has the ability to independently deploy at the expense of a non- licensed frequency. NB - IoT does not have such capabilities, since the frequency that it works requires a license, and the use of ready-made cellular networks makes it dependent on cellular companies and requires additional costs.
   
5. 
   LoRaWAN has the ability to install equipment in any hard-to-reach regions. Basically, the railway infrastructure is located in the extreme parts of cities and regions in which cellular communications do not work well. The use of NB - IoT with the help of existing cellular companies makes the quality of the transmitted data very low and at present this technology is not supported by cellular companies operating in Uzbekistan.
   
6. 
   Low prices when deploying LoRaWAN compared to NB- IoT. NB - IoT technology is one of the mos t modern, but the equipment is expensive.
   

c In this work, technological and technical comparisons between IoT types are made. Once again, it should be noted that the capabilities of the systems cover a

separate area of activity. By their nature, they are irreplaceable. You can, of course, combine and use positive abilities.
With regard to rail transport, a comparison of the three technologies showed the obvious advantage of the LoRaWAN network, which is more suitable for monitoring and controlling rolling stock.
Suggestions based on the results of the study:

1. 
   LoRaWAN should be used to track wagons.
   
2. 
   In urban areas, cellular technology should be used to track locomotives.
   
3. 
   It is advisable to use the capabilities of combined systems, including BLE , WiFi and LoRaWAN for larger tasks of monitoring railway assets.