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How to transfer data to 54 kilometers, if there is no 220V in the closet?

Information transfer via an autonomous wireless channel: the practice of building a long-distance WiFi network in sparsely populated areas of Kamchatka.



In our practice, we often meet with the opinion that WI-FI networks are used only for organizing wireless access in a small area or for links between networks for relatively short distances, about 5-10 km.
In this review, we present an example of the implementation of a wireless network on the Kamchatka Peninsula with distances between radio points up to 54 kilometers in extreme weather conditions with autonomous powering of remote points.

The WIFI network of the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences is part of the organization’s corporate network and has several segments located in different areas of Kamchatka. The network provides round-the-clock transmission of real-time seismic data. Separate points of this network are equipped with hardware complexes providing the transfer of not only seismic, but also various geophysical information and are additionally equipped with video cameras for monitoring volcanoes.
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One of the main segments of the wireless network is located in the districts of Petropavlovsk-Kamchatsky and Avachinsky Gulf, the remote points of the network are located in the region of the pass between the Avachinsky and Koryaksky volcanoes, as well as on the Pacific coast - Nalychevo and Russkaya Bay. All remote locations operate autonomously by using solar panels in tandem with batteries.

An example of a video image transmitted by the complex equipment. Volcano "Nameless".




Weak information about the climatic conditions of this region: the absolute maximum temperature reaches + 34 ° , the absolute minimum from minus 24-26 ° on the islands to minus 49-60 ° in the north and in Central Kamchatka.
The climate picture is complemented by winds. In winter, they rush over Kamchatka from the north, in summer they change to southern ones, therefore the average annual wind speed is quite moderate: from 1.3 to 8.8 m / s. In the winter season in the south of Kamchatka and on the Commander Islands wind speed reaches 40 m / s. The amount of precipitation depends on cyclones, and the maximum precipitation in this case is 1100-2600 mm per year.


When implementing a wireless network project, the following technical requirements were imposed on the equipment:


The following diagram shows the overall wireless network topology:

image

The scheme includes several extended sections using the Rapier radio equipment:


The table presents the main parameters of the links:



Two routes pass over the city (21km, 24km) and two above the water (54km, 51km).

As a basis for building the network, the Rapier radio routers were selected both as separate RS3-AP1-F5060-PTP blocks and as radio routers combined with RS3-AP1-F5060-PTP-TH antenna (monoblocks), providing all the technical requirements .
In the described topology, all radio links are configured in the "router" mode.
Each remote point has a separate IP subnet at 8 addresses for connecting scientific equipment.



Consider the option of organizing a wireless connection on the example of the Mayak Petropavlovsky link - Russkaya Bay (54 km).



The base station is installed on a stationary mast not far from the Petropavlovsk lighthouse.


Installation of a client data transfer station on a support structure made of pipes of various diameters, the coast of the Russkaya Bay.


A winter view of the same station from a different angle, a little further to see the shelter for a block of scientific equipment.


Planar antennas of the Mars Antennas MA-WA55-30 company were chosen as antennas. Taking into account the climatic conditions / wind loads, the antenna design had to be slightly modified, having strengthened the planar web along the perimeter with additional hardware.



Host structure:

For the permanent functioning of the system it was necessary to provide:



The first task was solved with the help of a standard set of fasteners for radio equipment; the planar antenna housing was additionally reinforced with hardware.

The task of providing guaranteed power supply was solved according to the following scheme:


The autonomous item included:



Solar panels provide recharging of the battery pack, the operation of which is controlled by the battery charge control unit.
Stabilization and power supply of radio equipment and devices is provided by converter units.

The use of solar panels and batteries with a large capacity allows you to charge the batteries during the day and provide power to the equipment at night. For a guaranteed battery charge throughout the year, 3 solar panels are used.

The battery pack is based on batteries with absorbed electrolyte and has the following characteristics:



The radio equipment of the Rapier RS3-AP1-F5060-PTP with the output power of 600 MW in tandem with the external antenna MA-WA55-30 is installed as radio equipment.

The block of scientific equipment includes seismic recorders (accelerometer and velocimeter).

Despite the limited availability, the network has been successfully operated for several years, starting in 2009. It should be noted that most of the remote points are not easily accessible; some of the points can only be reached in summer or winter; The point located in the Russkaya Bay is mainly accessible in the summer and only by helicopter.


We express our gratitude to the IT department of the CF GS GS RAS, in particular, the senior engineer of the department Artem Sumakov for help in preparing the material.

Source: https://habr.com/ru/post/167403/

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