How we provided communication in the cities of the Arctic Circle
The Arctic Circle is low temperatures and permafrost underfoot. The climate in these parts is sharply continental and severe. But here you need a connection. For example, in Salekhard and Labytnangi.
The harsh winter climate in Salekhard.
We modernized the mobile communications equipment in these cities and deployed a new core network. The mobile switch was transferred across the Ob River and teleported to new equipment. I was responsible for the organizational and technical parts of this northern project.
Salekhard is a center for exploration expeditions and at the same time a city of developed fishing industry. The city is located on the Ob River and has its own river port. Despite its remoteness from the "big" land, the city is the regional center of the Yamalo-Nenets Autonomous Okrug (Yamal-Nenets Autonomous Okrug or Yamal). In winter, the temperature here can drop to –40 degrees. The population of Salekhard is 47.9 thousand people. Next to this city, on the other side of the Ob River, just 16 km from it is another small town Labytnangi, which numbers 26.7 thousand people. About a third of the population of these two northern cities are subscribers of our company.
Any communication organization in the Yamal-Nenets Autonomous Region is not an easy task: the average annual temperatures are always negative, and from the end of November to the middle of February, a polar night reigns over a considerable territory of the region. At this time of the year, the sun rises briefly over the horizon and sets again, which does not contribute to the construction of new communication facilities. However, it was in these places that we started not just building a remote cell tower with on-board base stations, but decided to modernize the core mobile network to switch voice traffic.
The work of network modernization received the status of a special project in the company. It was the construction of a full-fledged 3G / 2G media gateway (what is it - more on that later), which is an integral part of our large switching system in the Yamal-Nenets Autonomous Region. By the way, in order to ensure the reliability of our networks, we have separate switching systems called mobile switches in each regional center. But for Yamal it was necessary to deploy a more “flexible” system.
At first it wasn’t even easy to “see” exactly where the remote backbone network was designed: the operator’s technical conditions in the regions are similar everywhere and are based on the centralized principle of scaling the basic architecture. We "tasted" the design issues for Yamal a little later, when the project "grew" with details. The main specificity that we encountered was that the costs of deploying a “remote” backbone network needed to be carefully and carefully planned, since the issue constantly bordered on the profitability of the modernization being undertaken.
Yamal-Nenets Autonomous Region, geographical location of Salekhard and Labytnangi
It so happened historically that on our old 2G mobile switch, serving subscribers in Salekhard and Labytnangi, it was not possible to configure new subscription services, this was simply not allowed by the platform. In particular, the mobile number transfer service between operators did not “rise”, and this was only the tip of the iceberg from a number of restrictions.
Further more. The old hall, in which 2G traffic of these cities of Yamal was switched, no longer had the opportunity to modernize, and there were no ways to expand it. The problem was that the racks of the new 3G / 2G media gateway and its entire modern “harness” had nowhere else to put in the existing room. In recent years, our mobile networks in the regions have begun to grow so rapidly, and the construction of base stations (BS), "carrying" subscriber traffic, has reached the level of a well-functioning "conveyor" that after only a few years in such relatively small cities it was again necessary to expand capacities networks for passing voice traffic. Moreover, we had the old machine room in the small town of Labytnangi, not even in the larger Salekhard, and it’s good to expand further, it was necessary to "cross" the river closer to the regional center and create a new mobile switching center there. All personnel of the company’s subsidiary, including technical, were located in Salekhard. It was necessary to somehow cut this "Gordian knot."
To further clarify the terminology, it is worth noting that the carrier-grade mobile switch is a large computer that connects subscriber calls and controls all 3G and 2G base stations providing cellular coverage in the region. The switch is the “heart” of the operator’s mobile network, a key architecture element of its “core” in the region. For 2G networks, the switch is called MSC (Mobile Switching Center), for 3G networks - MSS / MGW (Mobile Soft Switches / Media Gateway). The 3G switch is a universal network node and allows you to simultaneously process the voice traffic of base stations of both 3G and 2G. (At present, 2G MSC switches have been decommissioned from all VimpelCom regional networks from Kaliningrad to Kamchatka and are no longer in use, outdated. ) The principle of operation of a mobile switch is based on the automatic switching of tens of thousands of mobile voice calls from subscribers to each other. This “smart” multiprocessor machine is capable of optimally compressing and transmitting voice traffic of subscribers through the operator’s channels.
An important feature of our new 3G / 2G switches was that they are manufactured according to the principle of distributed architecture. This circumstance makes it possible to maximally “wrap up” local voice traffic of subscribers in small cities, by means of geographic “removal” of a separate 3G / 2G MGW (ie, a voice media gateway), and connecting local base station chain controllers to it. In fact, now, by installing a media gateway, you can build a “piece” of a mobile switch in remote cities closer to subscribers, and manage voice traffic using the MSS brains on “big land”. For subscribers who call their friends and family, by “wrapping” voice calls in place, the connection time and speech delays during a conversation are several times reduced. which significantly improves the quality of voice perception. It was the possibility of implementing the distributed architecture of the new switches that allowed us to design the installation of the switch component in Salekhard, without loading the large regional MSS / MGW switch, and dock the local voice traffic on the spot.
Labytnangi – Salekhard – Noyabrsk network diagram before modernization
“Big land” refers primarily to the “core” and the corresponding “bundle” of the large MSS / MGW switchboard of the Yamalo-Nenets Autonomous Area, which is located in our larger city Noyabrsk (and hereinafter - it is also remote support for colleagues from neighboring regional centers). According to our idea, now between Noyabrsky and Salekhard, spaced 600 km apart, the architecture allows transmitting only the signal exchange of subscriber traffic control, but not the voice traffic itself, which makes it possible to save on the rental of expensive transport channels to the northern cities of Yamal by reducing the consumed rented band.
Returning to the special project itself, one important fact should be noted. Our situation with the theoretical search for architecture for Yamal was finally pushed to practice by the fact that the supplier (a vendor) of a mobile switch serving subscribers in Salekhard and Labytnangi discontinued our 2G switching equipment, and after some time intended to complete its technical support. And as is usually the case in such cases, all the possible risks suddenly increased, and decisive action had to be taken. The project planning phase has ended overnight. The further time we spent already on the realization of the conceived idea of the optimal “wrapping” of voice traffic in local conditions in Salekhard.
Having developed and coordinated with the colleagues of the working group the interaction procedure for all designed subsystems, we began preparations for the construction. The first thing we did was go to Salekhard “to the fields” to collect information about the places for the possible placement of a new computer room for a media gateway.
After reviewing a lot of buildings and spending a lot of time, we made a disappointing conclusion. We did not fit any of the rooms that could be converted into a machine room for operator-class equipment. The rental price of more or less capital sites with all communications was quite high and unjustified for us. An important item of expenses indirectly invested in the price of the site was the cost of electricity in the city, taking into account two independent energy inputs and the further expansion of the capacities of our 2G and 3G coverage (and, in the future, 4G). And of course, the difficult moment of the choice was that we could not “pull” all our channels and communications to the studied points. This was a real "ambush" of the project that had not even begun.
Having considered all the possible options, we agreed that for these northern cities it was easier to build a machine room in the “point from scratch” at the desired point according to our operator conditions. Easy to say, but not so easy to do. After all, it was a question of permafrost and harsh northern climate, and “clean field” meant that the basis of the implementation of the machine room had to take the form of an airtight container on the ground. In the first place, as noted, two independent energy inputs should have been pulled up to it, and in the second, duplicated transport channels of communication via overhead radio relay links (RRL) would have been thrown. Essentially, for the local 3G / 2G MGW media gateway, it remained to build our own “house” reserved in all senses, equipping it with operator workstations.
Having prepared all the necessary equipment racks on the drawing of the future machine room, taking into account the expansion, we determined the appropriate container sizes and chose a place, starting construction on our own. Construction work on the site was logically divided into 2 stages. Stage 1 - construction of the main container, equipping it with “life support” systems for the machine room, connecting a video surveillance system, at the same time building a transformer substation in a separate container. Stage 2 - installation and installation of telecom equipment of the 3G / 2G backbone network, commissioning and integration of MGW, docking it with the “core” of the large MSS / MGW switch in Noyabrsk, as well as with the old switch in Labytnangi, multi-vendor testing of all subsystems with all verification of mobile services, and preparation of the entire system for pilot commercial operation.
The choice of construction companies-contractors for our "Wishlist" was made through a competition. Permafrost is not a joke. Then, together with contractors, in the spring we sent an order for the manufacture of a container to one of the steelworks in the Urals and began to wait for the end of production. Its impressive dimensions and weight were not typical for the standardly offered boxes for base stations, so the manufacturing was carried out “on order”.
Pile driving and foundation preparation for container
After painful waiting, the container was received from the factory and delivered to the place. The assembly of our "house" began immediately. In general, we can say that the construction of hardware boxes in the north is a responsible and very laborious matter. And our container for the new 3G / 2G media gateway was built in accordance with all the technological stages of building hardware boxes for these parts. We did not experience any insurmountable difficulties, for example with soils, in this part of the project, the construction of the “house” was completed without force majeure.
The container of the mashroom turned out to be reliable, with enhanced thermal and waterproofing. Air conditioners and an automatic heating system were installed in it. The operating temperature in the container is constantly maintained at about 22 degrees, full climate control works. There are fire, flood sensors and a full monitoring system that allows you to detect cases of malfunctions. In addition, at the site in a separate container, our own transformer substation with the necessary distribution devices was assembled.
Transformer substation connected switchgears
According to the results of the 1st construction stage with a small symbolic “housewarming”, we launched the container of the machine room into operation, and it was already possible to “live” on the site. Further it was necessary to accelerate with the 2nd stage, as we began to tighten the cold.
Along with the container manufacturing work, all the necessary 3G / 2G telecom equipment for the core network was purchased, and it was already waiting for us at the regional warehouse. But the protracted deadlines for the manufacture and delivery of our "home" from the factory, as well as the assembly by contractors, and in addition, the launch of its own transformer substation at the site, delayed the availability of the first stage of the project in late autumn. The short summers and autumns ended, it began to snow in the Arctic Circle, and it was important to “catch up” with the implementation of the 2nd stage: delivery and tests of the purchased switching equipment.
Our experience of working with the north led us to the fact that sending operator equipment by rail from a warehouse located in our city in Tyumen had to be done at least a month in advance, or better even earlier. The train with racks could reach our place in the Arctic Circle only through Syktyvkar, passing at the same time bypassing another 4 regions, and reaching only the railway station in Labytnangi. There were no further ways, and the Ob River blocked the road to our site. There is no railway from Labytnangi to Salekhard, bridges too. Given this circumstance, we tried to send the equipment to the Labytnangi transport company in more than a month, promptly unload it from the railway upon arrival, and head to the ferry across the river. If you knew that planning logistics on the "big" land is so early,
We only needed 5 hours of the last day of this route to ferry all our numerous crates and boxes. By the way, there was an opportunity for people to cross the river, in the off-season there is an air-cushion boat, like an urban minibus, but there was no longer a road through the river for freight transport. The river at once “cut off” all possible attempts to get to a remote site.
Salekhard – Labytnangi winter crossing across the Ob River
It sometimes happens. We stuffed our “package” to both northern cities with all the necessary “iron” and even with a reserve, we drove it for a month by rail, since we could not send such cargo by airmail, and we did not manage to do it quite a bit. And there was nothing left to do except wait for three weeks “by the sea of weather”, until a safe road opens again for the passage of freight transport across the Ob River, but now on winter ice, called the “winter road”. But survived this. However, who would have thought then that it was precisely this chain of shift of dates and the arrival of prolonged negative temperatures to the north that would only help us with the full launch of the new 3G / 2G media gateway in operation in harsh climatic conditions.
As soon as all the necessary boxes with the Telecom “iron” were delivered to the machine room, representatives of the new equipment vendors were “abandoned” by flights, and the work “began to boil” at an accelerated pace. Engineers were notified of the work in advance, and on the appointed days and hours they flew to our Salekhard one by one, without interfering, and without delaying each other, waiting for their integration deadlines, which was very valuable. Together with our technical colleagues, the vendors and their contractors docked the various subsystems of the core network with each other, exchanged experiences, tested and retested, and soon the work gained momentum. The system began to grow together before our eyes.
Installation of telecom equipment in the new machine room
The testing of the new 3G / 2G MGW media gateway was carried out at two test base stations 3G and 2G, assembled here in the container, but connected to the test antennas via attenuators. Having configured the necessary thresholds for signal levels of base stations, we confidently passed all the tuning tests of 3G-2G-3G mobile transitions on test smartphones. Similarly, all MSS – MGW signaling tests between cities were performed, then mobile service tests. As a result, all the necessary network elements of the core network and traffic control systems "rose" in the machine room. And naturally, backup batteries were also tested and commissioned. Our 2nd construction phase at the site smoothly came to an end and the tested backbone network was finally ready to receive traffic.
Battery backup
It is worth noting that the specifics of project management in Yamal was that in these northern cities we constantly lacked technical specialists. I had to look for engineers from neighboring regions specializing in similar mobile subsystems in the company and ask my colleagues to travel north to help vendors and local technical colleagues to optimally configure the hardware for the common requirements of a large company’s networks. After all, local colleagues in Salekhard were not the adjusters of the new hardware, although in the process of jointly setting up the switching network they became real multi-station operators specializing in equipping a wide variety of subsystems. As a result, the project rolled out to the “home stretch”, and ahead of us was the transfer of “live” subscriber traffic.
Next, it was necessary to transfer the subscriber traffic of all base stations of two remote cities of Yamal to the new, just rebuilt 3G / 2G MGW media gateway. The hours of the most crucial moment of this special project were rapidly approaching. As mentioned earlier, the preparation for the transfer of commercial mobile traffic was that in the project at the new site, the duplicate of the switching equipment was first “raised” to the “hot reserve”, and only then the way was opened for switching the voice traffic of subscribers with the possibility of “rollback” old configuration in case of problems. Now, in two mashrooms on both sides of the Ob River, everything was ready for this.
Elements of the rebuilt system (from left to right): air conditioning, MGW media gateway, 3G base station controller
As one of our colleagues participating in the project figuratively noted, the transfer of subscriber traffic resembled the transfer of commercial passengers from an old plane to a modern airliner. Imagine for a moment that you are a member of the crew of a passenger plane flying over the Atlantic. It is required of you right in flight to quickly transfer all passengers to a new reliable liner flying next to a parallel course. But passengers do not need to know about this: they fly about their business, relax with a newspaper, or sleep soundly, the flight goes fine. Not too real a task, is it? With our mobile network in two remote cities of Yamal, it was necessary to do the same.
It is impossible to stop the operation of the telephone network during the “flight”, prepare the telecom equipment, establish it, and then safely continue the “flight” in the modernized conditions. In a short time we needed not only painlessly for subscribers to transfer the entire radio part from the chains of base stations, controlling the process remotely over 600 km from Noyabrsk with support from regional centers. We needed to save everything that had already been accumulated for subscribers of the northern cities over the years of the 2G network: connecting SMS and MMS centers, interfaces with numerous service platforms, connections with other mobile and fixed operators, mini-automatic telephone exchanges, and many much more. In the process of transferring mobile traffic, there should not be the slightest impact on the network and services, the “drawdown” of quality is not permissible here.
To carry out this stage of the project, it was necessary to carry out a substantial documentary study: what, why, and in what sequence it switches, how traffic flows, how new network elements load, etc. The configuration and switching of mobile traffic itself is performed on the same day in the dead of night with minimal network load. But this is if everything goes according to plan.
When debugging traffic transfer between the switches in Labytnangi and Salekhard, a certain difficulty was caused by the simultaneous “docking” work in the halls on both sides of the Ob River. We had to cross the river more than once on a winter boat or a passenger car and “pull up” some expanding hardware to a new site, various blocks for 3G and 2G networks, modules, boards, cables, connectors, and more stuff, stuff. The transfer of mobile traffic from the old to the new mashine itself was to be carried out via overhead radio links.
Radio relay antennas, primary and backup channels
To begin with, we decided to check the readiness of the transport network for transfer and submit a small transit traffic to the new site via relays in order to observe errors in the channels in the pilot commercial mode. Something suggested that it was too early to load the full-fledged subscriber traffic, it had to be done gradually. And according to the results of the trial inclusion, the picture was really not rosy. The signal level of the relays at the new site “floated” aperiodically, the parameters of the radio channels either deteriorated or improved, leading to partial “sticking” of the lines. A full-fledged traffic switching was postponed until the reasons for the relay "transport" were clarified.
As it turned out later, the reason for the “floating” effect in the radio channels was that we had partially frozen out the new radio-relay equipment installed on the roof of our container. We did not plan to make mobile network settings in winter in severe climatic conditions, rather the opposite, but, as noted earlier, the construction was delayed and nature itself now “told” us that before relaying the system into operation, new relays should be changed to more reliable ones. Soon, after replacing the relays, the connection with the new engine room was stable.
Built site: on the left is the container of the transformer substation, on the right is the container of the new hall
Finally, the hour "X" of this northern "adventure" has come. Colleagues in different cities of our company went to night work to remotely support the north with their participation on various 3G and 2G control subsystems. In the dead of night, when both cities were falling asleep, on all the separated sites in Salekhard and Labytnangi, all the necessary transport channels were opened to transfer traffic. The old and the new switch were “docked”.
Subscribers from the old switch began to “teleport” to the new media gateway, in the normal mode and without too much fuss. The 3G / 2G backbone network “received” first hundreds, and then thousands of voice calls from subscribers in the northern cities of Yamal and began their switching, glowing on the boards of the new machine room with bright LED indicators. There were no “kickbacks” to the initial configuration that night, and a new “life” was successfully “brought” to the site and cultivated. There were no fatal equipment failures under load. By morning, the configuration and transfer of traffic on all subsystems were successfully completed, and the old mobile switch was “released” from internal subscriber traffic.
The whole next day before the “night” shift of our colleagues from the front line of these “military” operations, it was impossible to get through with congratulations, many had to be sought later. Everyone disappeared somewhere and turned off the mobile phones on the spot, having gone into a deep sleep. It was a good sign. Work with the most stressful part of the project, transferring internal traffic of subscribers to the new hardware, was completed, and duplicated transport channels in Salekhard did not disappoint us. Now it was possible to calmly load the MGW remote 3G / 2G media gateway with the remaining traffic.
Moving a little away from the artillery preparation of transferring internal traffic and not putting it on hold, the next call we implemented the transfer of external mobile traffic - the so-called traffic of “connecting” connection channels with other operators. This had to be done so that our subscribers in Salekhard and Labytnangi could now freely call regional subscribers of other telecom operators through the same new media gateway. To this end, the technical conditions of “docking” were preliminarily agreed with each local telephone service provider and call switching tests were passed. After that, our new 3G / 2G MGW media gateway was “tied” to the switches of other operators in the Yamalo-Nenets Autonomous Region. Similarly, through tests and monitoring, all the remaining technical traffic was transferred to the new hardware.
The outcome of this story was logical and logical. We did not abandon the old hall, but transformed it. After removing all the subscriber load, the old mobile switch was “muffled”, its technical support was successfully completed, and the outdated hardware was dismantled to the warehouse, clearing space for new racks to expand access network coverage. Thus, “closing the circle”, the next round of equipment modernization was implemented on the old site from a series of our ongoing technical work to optimize the network.
As a result of the work done and the construction of the 3G / 2G MGW media gateway, a distributed core network architecture was implemented in the Yamal-Nenets Autonomous Region. We brought the media gateway closer to the remote subscribers and “wrapped” the local voice traffic in place, thereby reducing the time of establishing connections and delays in voice transmission to residents of northern cities. Disruption of voice calls was also reduced at the borders of 3G and 2G access networks, since now all calls are processed on the MGW single 3G / 2G media gateway, which is “tailored” to work in two standards.
All equipment built in the new hall was transferred “for storage” to local technical colleagues and it was set up to work in automatic mode. In case of problems, all equipment supports remote configuration modes from the "big" land. And there are always colleagues nearby who monitor various emergency situations. If something is wrong, then colleagues are able to “distort” cables and boards on their own.
The upgraded 3G / 2G backbone network at the new media gateway optimally worked out the peak New Year call loads in Salekhard and Labytnangi. The network worked without failures and did not go to the “overshoot” from congestion, and the subscribers were able to congratulate each other Happy New Year without any problems. It was valuable.
Cold weather at the beginning of this winter at –40 degrees, and continuing after the New Year, had no effect on the core mobile network in Salekhard. Transport equipment, energy and all the systems on the site worked normally. And our subscribers of the northern cities felt confident.
In conclusion, I would like to thank all the colleagues who took part in the development, design and implementation of this northern project: Surgut, Tyumen, Chelyabinsk branches, VimpelCom management of the Ural region, vendors and contractors. The entire working group of the project worked quite synchronously, like a single living organism. The volume of work performed has become for us in some way our own “conquest” of the latitudes of the Arctic Circle. And it was a truly unforgettable experience.
The harsh winter climate in Salekhard.
We modernized the mobile communications equipment in these cities and deployed a new core network. The mobile switch was transferred across the Ob River and teleported to new equipment. I was responsible for the organizational and technical parts of this northern project.
Background
Salekhard is a center for exploration expeditions and at the same time a city of developed fishing industry. The city is located on the Ob River and has its own river port. Despite its remoteness from the "big" land, the city is the regional center of the Yamalo-Nenets Autonomous Okrug (Yamal-Nenets Autonomous Okrug or Yamal). In winter, the temperature here can drop to –40 degrees. The population of Salekhard is 47.9 thousand people. Next to this city, on the other side of the Ob River, just 16 km from it is another small town Labytnangi, which numbers 26.7 thousand people. About a third of the population of these two northern cities are subscribers of our company.
Any communication organization in the Yamal-Nenets Autonomous Region is not an easy task: the average annual temperatures are always negative, and from the end of November to the middle of February, a polar night reigns over a considerable territory of the region. At this time of the year, the sun rises briefly over the horizon and sets again, which does not contribute to the construction of new communication facilities. However, it was in these places that we started not just building a remote cell tower with on-board base stations, but decided to modernize the core mobile network to switch voice traffic.
The work of network modernization received the status of a special project in the company. It was the construction of a full-fledged 3G / 2G media gateway (what is it - more on that later), which is an integral part of our large switching system in the Yamal-Nenets Autonomous Region. By the way, in order to ensure the reliability of our networks, we have separate switching systems called mobile switches in each regional center. But for Yamal it was necessary to deploy a more “flexible” system.
At first it wasn’t even easy to “see” exactly where the remote backbone network was designed: the operator’s technical conditions in the regions are similar everywhere and are based on the centralized principle of scaling the basic architecture. We "tasted" the design issues for Yamal a little later, when the project "grew" with details. The main specificity that we encountered was that the costs of deploying a “remote” backbone network needed to be carefully and carefully planned, since the issue constantly bordered on the profitability of the modernization being undertaken.
Yamal-Nenets Autonomous Region, geographical location of Salekhard and Labytnangi
It so happened historically that on our old 2G mobile switch, serving subscribers in Salekhard and Labytnangi, it was not possible to configure new subscription services, this was simply not allowed by the platform. In particular, the mobile number transfer service between operators did not “rise”, and this was only the tip of the iceberg from a number of restrictions.
Further more. The old hall, in which 2G traffic of these cities of Yamal was switched, no longer had the opportunity to modernize, and there were no ways to expand it. The problem was that the racks of the new 3G / 2G media gateway and its entire modern “harness” had nowhere else to put in the existing room. In recent years, our mobile networks in the regions have begun to grow so rapidly, and the construction of base stations (BS), "carrying" subscriber traffic, has reached the level of a well-functioning "conveyor" that after only a few years in such relatively small cities it was again necessary to expand capacities networks for passing voice traffic. Moreover, we had the old machine room in the small town of Labytnangi, not even in the larger Salekhard, and it’s good to expand further, it was necessary to "cross" the river closer to the regional center and create a new mobile switching center there. All personnel of the company’s subsidiary, including technical, were located in Salekhard. It was necessary to somehow cut this "Gordian knot."
To further clarify the terminology, it is worth noting that the carrier-grade mobile switch is a large computer that connects subscriber calls and controls all 3G and 2G base stations providing cellular coverage in the region. The switch is the “heart” of the operator’s mobile network, a key architecture element of its “core” in the region. For 2G networks, the switch is called MSC (Mobile Switching Center), for 3G networks - MSS / MGW (Mobile Soft Switches / Media Gateway). The 3G switch is a universal network node and allows you to simultaneously process the voice traffic of base stations of both 3G and 2G. (At present, 2G MSC switches have been decommissioned from all VimpelCom regional networks from Kaliningrad to Kamchatka and are no longer in use, outdated. ) The principle of operation of a mobile switch is based on the automatic switching of tens of thousands of mobile voice calls from subscribers to each other. This “smart” multiprocessor machine is capable of optimally compressing and transmitting voice traffic of subscribers through the operator’s channels.
An important feature of our new 3G / 2G switches was that they are manufactured according to the principle of distributed architecture. This circumstance makes it possible to maximally “wrap up” local voice traffic of subscribers in small cities, by means of geographic “removal” of a separate 3G / 2G MGW (ie, a voice media gateway), and connecting local base station chain controllers to it. In fact, now, by installing a media gateway, you can build a “piece” of a mobile switch in remote cities closer to subscribers, and manage voice traffic using the MSS brains on “big land”. For subscribers who call their friends and family, by “wrapping” voice calls in place, the connection time and speech delays during a conversation are several times reduced. which significantly improves the quality of voice perception. It was the possibility of implementing the distributed architecture of the new switches that allowed us to design the installation of the switch component in Salekhard, without loading the large regional MSS / MGW switch, and dock the local voice traffic on the spot.
Labytnangi – Salekhard – Noyabrsk network diagram before modernization
“Big land” refers primarily to the “core” and the corresponding “bundle” of the large MSS / MGW switchboard of the Yamalo-Nenets Autonomous Area, which is located in our larger city Noyabrsk (and hereinafter - it is also remote support for colleagues from neighboring regional centers). According to our idea, now between Noyabrsky and Salekhard, spaced 600 km apart, the architecture allows transmitting only the signal exchange of subscriber traffic control, but not the voice traffic itself, which makes it possible to save on the rental of expensive transport channels to the northern cities of Yamal by reducing the consumed rented band.
Returning to the special project itself, one important fact should be noted. Our situation with the theoretical search for architecture for Yamal was finally pushed to practice by the fact that the supplier (a vendor) of a mobile switch serving subscribers in Salekhard and Labytnangi discontinued our 2G switching equipment, and after some time intended to complete its technical support. And as is usually the case in such cases, all the possible risks suddenly increased, and decisive action had to be taken. The project planning phase has ended overnight. The further time we spent already on the realization of the conceived idea of the optimal “wrapping” of voice traffic in local conditions in Salekhard.
Construction of the hall and equipment setup
Having developed and coordinated with the colleagues of the working group the interaction procedure for all designed subsystems, we began preparations for the construction. The first thing we did was go to Salekhard “to the fields” to collect information about the places for the possible placement of a new computer room for a media gateway.
After reviewing a lot of buildings and spending a lot of time, we made a disappointing conclusion. We did not fit any of the rooms that could be converted into a machine room for operator-class equipment. The rental price of more or less capital sites with all communications was quite high and unjustified for us. An important item of expenses indirectly invested in the price of the site was the cost of electricity in the city, taking into account two independent energy inputs and the further expansion of the capacities of our 2G and 3G coverage (and, in the future, 4G). And of course, the difficult moment of the choice was that we could not “pull” all our channels and communications to the studied points. This was a real "ambush" of the project that had not even begun.
Having considered all the possible options, we agreed that for these northern cities it was easier to build a machine room in the “point from scratch” at the desired point according to our operator conditions. Easy to say, but not so easy to do. After all, it was a question of permafrost and harsh northern climate, and “clean field” meant that the basis of the implementation of the machine room had to take the form of an airtight container on the ground. In the first place, as noted, two independent energy inputs should have been pulled up to it, and in the second, duplicated transport channels of communication via overhead radio relay links (RRL) would have been thrown. Essentially, for the local 3G / 2G MGW media gateway, it remained to build our own “house” reserved in all senses, equipping it with operator workstations.
Having prepared all the necessary equipment racks on the drawing of the future machine room, taking into account the expansion, we determined the appropriate container sizes and chose a place, starting construction on our own. Construction work on the site was logically divided into 2 stages. Stage 1 - construction of the main container, equipping it with “life support” systems for the machine room, connecting a video surveillance system, at the same time building a transformer substation in a separate container. Stage 2 - installation and installation of telecom equipment of the 3G / 2G backbone network, commissioning and integration of MGW, docking it with the “core” of the large MSS / MGW switch in Noyabrsk, as well as with the old switch in Labytnangi, multi-vendor testing of all subsystems with all verification of mobile services, and preparation of the entire system for pilot commercial operation.
The choice of construction companies-contractors for our "Wishlist" was made through a competition. Permafrost is not a joke. Then, together with contractors, in the spring we sent an order for the manufacture of a container to one of the steelworks in the Urals and began to wait for the end of production. Its impressive dimensions and weight were not typical for the standardly offered boxes for base stations, so the manufacturing was carried out “on order”.
Pile driving and foundation preparation for container
After painful waiting, the container was received from the factory and delivered to the place. The assembly of our "house" began immediately. In general, we can say that the construction of hardware boxes in the north is a responsible and very laborious matter. And our container for the new 3G / 2G media gateway was built in accordance with all the technological stages of building hardware boxes for these parts. We did not experience any insurmountable difficulties, for example with soils, in this part of the project, the construction of the “house” was completed without force majeure.
The container of the mashroom turned out to be reliable, with enhanced thermal and waterproofing. Air conditioners and an automatic heating system were installed in it. The operating temperature in the container is constantly maintained at about 22 degrees, full climate control works. There are fire, flood sensors and a full monitoring system that allows you to detect cases of malfunctions. In addition, at the site in a separate container, our own transformer substation with the necessary distribution devices was assembled.
Transformer substation connected switchgears
According to the results of the 1st construction stage with a small symbolic “housewarming”, we launched the container of the machine room into operation, and it was already possible to “live” on the site. Further it was necessary to accelerate with the 2nd stage, as we began to tighten the cold.
Along with the container manufacturing work, all the necessary 3G / 2G telecom equipment for the core network was purchased, and it was already waiting for us at the regional warehouse. But the protracted deadlines for the manufacture and delivery of our "home" from the factory, as well as the assembly by contractors, and in addition, the launch of its own transformer substation at the site, delayed the availability of the first stage of the project in late autumn. The short summers and autumns ended, it began to snow in the Arctic Circle, and it was important to “catch up” with the implementation of the 2nd stage: delivery and tests of the purchased switching equipment.
Our experience of working with the north led us to the fact that sending operator equipment by rail from a warehouse located in our city in Tyumen had to be done at least a month in advance, or better even earlier. The train with racks could reach our place in the Arctic Circle only through Syktyvkar, passing at the same time bypassing another 4 regions, and reaching only the railway station in Labytnangi. There were no further ways, and the Ob River blocked the road to our site. There is no railway from Labytnangi to Salekhard, bridges too. Given this circumstance, we tried to send the equipment to the Labytnangi transport company in more than a month, promptly unload it from the railway upon arrival, and head to the ferry across the river. If you knew that planning logistics on the "big" land is so early,
We only needed 5 hours of the last day of this route to ferry all our numerous crates and boxes. By the way, there was an opportunity for people to cross the river, in the off-season there is an air-cushion boat, like an urban minibus, but there was no longer a road through the river for freight transport. The river at once “cut off” all possible attempts to get to a remote site.
Salekhard – Labytnangi winter crossing across the Ob River
It sometimes happens. We stuffed our “package” to both northern cities with all the necessary “iron” and even with a reserve, we drove it for a month by rail, since we could not send such cargo by airmail, and we did not manage to do it quite a bit. And there was nothing left to do except wait for three weeks “by the sea of weather”, until a safe road opens again for the passage of freight transport across the Ob River, but now on winter ice, called the “winter road”. But survived this. However, who would have thought then that it was precisely this chain of shift of dates and the arrival of prolonged negative temperatures to the north that would only help us with the full launch of the new 3G / 2G media gateway in operation in harsh climatic conditions.
As soon as all the necessary boxes with the Telecom “iron” were delivered to the machine room, representatives of the new equipment vendors were “abandoned” by flights, and the work “began to boil” at an accelerated pace. Engineers were notified of the work in advance, and on the appointed days and hours they flew to our Salekhard one by one, without interfering, and without delaying each other, waiting for their integration deadlines, which was very valuable. Together with our technical colleagues, the vendors and their contractors docked the various subsystems of the core network with each other, exchanged experiences, tested and retested, and soon the work gained momentum. The system began to grow together before our eyes.
Installation of telecom equipment in the new machine room
The testing of the new 3G / 2G MGW media gateway was carried out at two test base stations 3G and 2G, assembled here in the container, but connected to the test antennas via attenuators. Having configured the necessary thresholds for signal levels of base stations, we confidently passed all the tuning tests of 3G-2G-3G mobile transitions on test smartphones. Similarly, all MSS – MGW signaling tests between cities were performed, then mobile service tests. As a result, all the necessary network elements of the core network and traffic control systems "rose" in the machine room. And naturally, backup batteries were also tested and commissioned. Our 2nd construction phase at the site smoothly came to an end and the tested backbone network was finally ready to receive traffic.
Battery backup
It is worth noting that the specifics of project management in Yamal was that in these northern cities we constantly lacked technical specialists. I had to look for engineers from neighboring regions specializing in similar mobile subsystems in the company and ask my colleagues to travel north to help vendors and local technical colleagues to optimally configure the hardware for the common requirements of a large company’s networks. After all, local colleagues in Salekhard were not the adjusters of the new hardware, although in the process of jointly setting up the switching network they became real multi-station operators specializing in equipping a wide variety of subsystems. As a result, the project rolled out to the “home stretch”, and ahead of us was the transfer of “live” subscriber traffic.
Subscriber traffic transfer
Next, it was necessary to transfer the subscriber traffic of all base stations of two remote cities of Yamal to the new, just rebuilt 3G / 2G MGW media gateway. The hours of the most crucial moment of this special project were rapidly approaching. As mentioned earlier, the preparation for the transfer of commercial mobile traffic was that in the project at the new site, the duplicate of the switching equipment was first “raised” to the “hot reserve”, and only then the way was opened for switching the voice traffic of subscribers with the possibility of “rollback” old configuration in case of problems. Now, in two mashrooms on both sides of the Ob River, everything was ready for this.
Elements of the rebuilt system (from left to right): air conditioning, MGW media gateway, 3G base station controller
As one of our colleagues participating in the project figuratively noted, the transfer of subscriber traffic resembled the transfer of commercial passengers from an old plane to a modern airliner. Imagine for a moment that you are a member of the crew of a passenger plane flying over the Atlantic. It is required of you right in flight to quickly transfer all passengers to a new reliable liner flying next to a parallel course. But passengers do not need to know about this: they fly about their business, relax with a newspaper, or sleep soundly, the flight goes fine. Not too real a task, is it? With our mobile network in two remote cities of Yamal, it was necessary to do the same.
It is impossible to stop the operation of the telephone network during the “flight”, prepare the telecom equipment, establish it, and then safely continue the “flight” in the modernized conditions. In a short time we needed not only painlessly for subscribers to transfer the entire radio part from the chains of base stations, controlling the process remotely over 600 km from Noyabrsk with support from regional centers. We needed to save everything that had already been accumulated for subscribers of the northern cities over the years of the 2G network: connecting SMS and MMS centers, interfaces with numerous service platforms, connections with other mobile and fixed operators, mini-automatic telephone exchanges, and many much more. In the process of transferring mobile traffic, there should not be the slightest impact on the network and services, the “drawdown” of quality is not permissible here.
To carry out this stage of the project, it was necessary to carry out a substantial documentary study: what, why, and in what sequence it switches, how traffic flows, how new network elements load, etc. The configuration and switching of mobile traffic itself is performed on the same day in the dead of night with minimal network load. But this is if everything goes according to plan.
When debugging traffic transfer between the switches in Labytnangi and Salekhard, a certain difficulty was caused by the simultaneous “docking” work in the halls on both sides of the Ob River. We had to cross the river more than once on a winter boat or a passenger car and “pull up” some expanding hardware to a new site, various blocks for 3G and 2G networks, modules, boards, cables, connectors, and more stuff, stuff. The transfer of mobile traffic from the old to the new mashine itself was to be carried out via overhead radio links.
Radio relay antennas, primary and backup channels
To begin with, we decided to check the readiness of the transport network for transfer and submit a small transit traffic to the new site via relays in order to observe errors in the channels in the pilot commercial mode. Something suggested that it was too early to load the full-fledged subscriber traffic, it had to be done gradually. And according to the results of the trial inclusion, the picture was really not rosy. The signal level of the relays at the new site “floated” aperiodically, the parameters of the radio channels either deteriorated or improved, leading to partial “sticking” of the lines. A full-fledged traffic switching was postponed until the reasons for the relay "transport" were clarified.
As it turned out later, the reason for the “floating” effect in the radio channels was that we had partially frozen out the new radio-relay equipment installed on the roof of our container. We did not plan to make mobile network settings in winter in severe climatic conditions, rather the opposite, but, as noted earlier, the construction was delayed and nature itself now “told” us that before relaying the system into operation, new relays should be changed to more reliable ones. Soon, after replacing the relays, the connection with the new engine room was stable.
Built site: on the left is the container of the transformer substation, on the right is the container of the new hall
Finally, the hour "X" of this northern "adventure" has come. Colleagues in different cities of our company went to night work to remotely support the north with their participation on various 3G and 2G control subsystems. In the dead of night, when both cities were falling asleep, on all the separated sites in Salekhard and Labytnangi, all the necessary transport channels were opened to transfer traffic. The old and the new switch were “docked”.
Subscribers from the old switch began to “teleport” to the new media gateway, in the normal mode and without too much fuss. The 3G / 2G backbone network “received” first hundreds, and then thousands of voice calls from subscribers in the northern cities of Yamal and began their switching, glowing on the boards of the new machine room with bright LED indicators. There were no “kickbacks” to the initial configuration that night, and a new “life” was successfully “brought” to the site and cultivated. There were no fatal equipment failures under load. By morning, the configuration and transfer of traffic on all subsystems were successfully completed, and the old mobile switch was “released” from internal subscriber traffic.
The whole next day before the “night” shift of our colleagues from the front line of these “military” operations, it was impossible to get through with congratulations, many had to be sought later. Everyone disappeared somewhere and turned off the mobile phones on the spot, having gone into a deep sleep. It was a good sign. Work with the most stressful part of the project, transferring internal traffic of subscribers to the new hardware, was completed, and duplicated transport channels in Salekhard did not disappoint us. Now it was possible to calmly load the MGW remote 3G / 2G media gateway with the remaining traffic.
Moving a little away from the artillery preparation of transferring internal traffic and not putting it on hold, the next call we implemented the transfer of external mobile traffic - the so-called traffic of “connecting” connection channels with other operators. This had to be done so that our subscribers in Salekhard and Labytnangi could now freely call regional subscribers of other telecom operators through the same new media gateway. To this end, the technical conditions of “docking” were preliminarily agreed with each local telephone service provider and call switching tests were passed. After that, our new 3G / 2G MGW media gateway was “tied” to the switches of other operators in the Yamalo-Nenets Autonomous Region. Similarly, through tests and monitoring, all the remaining technical traffic was transferred to the new hardware.
The outcome of this story was logical and logical. We did not abandon the old hall, but transformed it. After removing all the subscriber load, the old mobile switch was “muffled”, its technical support was successfully completed, and the outdated hardware was dismantled to the warehouse, clearing space for new racks to expand access network coverage. Thus, “closing the circle”, the next round of equipment modernization was implemented on the old site from a series of our ongoing technical work to optimize the network.
Summary
As a result of the work done and the construction of the 3G / 2G MGW media gateway, a distributed core network architecture was implemented in the Yamal-Nenets Autonomous Region. We brought the media gateway closer to the remote subscribers and “wrapped” the local voice traffic in place, thereby reducing the time of establishing connections and delays in voice transmission to residents of northern cities. Disruption of voice calls was also reduced at the borders of 3G and 2G access networks, since now all calls are processed on the MGW single 3G / 2G media gateway, which is “tailored” to work in two standards.
All equipment built in the new hall was transferred “for storage” to local technical colleagues and it was set up to work in automatic mode. In case of problems, all equipment supports remote configuration modes from the "big" land. And there are always colleagues nearby who monitor various emergency situations. If something is wrong, then colleagues are able to “distort” cables and boards on their own.
The upgraded 3G / 2G backbone network at the new media gateway optimally worked out the peak New Year call loads in Salekhard and Labytnangi. The network worked without failures and did not go to the “overshoot” from congestion, and the subscribers were able to congratulate each other Happy New Year without any problems. It was valuable.
Cold weather at the beginning of this winter at –40 degrees, and continuing after the New Year, had no effect on the core mobile network in Salekhard. Transport equipment, energy and all the systems on the site worked normally. And our subscribers of the northern cities felt confident.
In conclusion, I would like to thank all the colleagues who took part in the development, design and implementation of this northern project: Surgut, Tyumen, Chelyabinsk branches, VimpelCom management of the Ural region, vendors and contractors. The entire working group of the project worked quite synchronously, like a single living organism. The volume of work performed has become for us in some way our own “conquest” of the latitudes of the Arctic Circle. And it was a truly unforgettable experience.