When three years ago we did memory cards for industrial use, in the comments there were wishes not to talk about drones and cameras - they say, this is not a typical area of ββapplication for such memory cards. OK, we told ourselves and wrote it down in the content plan - make a publication with a case from industry. But, as it happens, behind the flow of publications about new Kingston products, this item remained on the backlist for a long time, until it was here, on HabrΓ©, that we met . She has been using these memory cards since 2016, and uses hundreds of them. By the way, in its 40-gigabit radio bridge across the Yenisei, which delivered wireless communication, memory cards are installed .
The subject area of ββthe case is broadband communications on millimeter waves
At the turn of 2016, that is, exactly when the Kingston industrial-grade memory cards from our review appeared, a qualitative leap in the speed of backbone wireless radio links was being prepared in the telecommunications market. The second generation of radio relay stations at a speed of 1 Gbit/s, dominant in 2010-2015, was supposed to pass the baton to third generation radio links capable of operating in the 10 Gigabit Ethernet standard and transmitting data at a speed of 10 Gbit/s.
Radio bridges 2x20 Gbit/s across the Yenisei in Igarka. Source: DOK LLC
By the way, in order to make a radio channel with transmission characteristics similar to an optical cable, at least a couple of things were required on a global scale: the creation of a new element base for wireless communication 10 Gigabit Ethernet (10GE) and the allocation of a frequency range sufficient in width where it is possible to βfitβ 10 - gigabit data stream. This range was the set of frequencies 71-76/81-86 GHz, which, with the light hand of the American regulator FCC, was allocated in the USA in 2008. Soon this example was followed by regulators in almost all countries of the world, including Russia (the 71-76/81-86 GHz range has been permitted by the Ministry of Communications of the Russian Federation for free use since 2010).
In 2016, the MMIC chips (microwave monolithic integrated circuits) that designers needed, capable of providing QAM 256 radio signal modulation for a data transfer rate of 10 Gbit/s, finally appeared on the world market, and the race began to see who would be the first to launch commercial samples of class radio relay equipment on the market. 10GE. Surprisingly, the first production sample of such radio links was created in Russia at the St. Petersburg engineering company DOK and shown at the Mobile World Congress (MWC 2017) in Barcelona in 2017. Well, why not? - after all, Alexander Popov invented radio in St. Petersburg (although this primacy is sometimes attributed to Marconi or Tesla).
Today, in 2019, 10GE wireless radios have become the de facto industry standard. Thanks to its high throughput, one 10 Gbit/s radio relay line often serves a whole residential neighborhood or large industrial area with communications. Cellular operators willingly use 10GE radio links for backbones between 4G/LTE base stations, because they ensure synchronization of base stations with the reference clock of the cellular operator's data center, which is important for transmitting multimedia traffic to smartphones and tablets. In addition to digital telephony and Internet access, hundreds of digital TV channels are broadcast via a 10 Gigabit Ethernet wireless channel, and there is a stream of data from CCTV cameras.
βThis is all interesting in its own way,β Habrβs reader will say, βbut what does Kingston memory cards have to do with it?β But this is what we will now move on to.
"Black box" inside radio relay equipment
Memory card installed in the control module of the PPC-10G radio relay station manufactured by DOK as a file storage for configuration files and logging of equipment status. All critical operating parameters are written to the card around the clock: data transfer rate in the channel, received signal level (RSL, Receive Signal Level), temperature in the case, power supply parameters and much more. According to the manufacturer's rules, the card must store such data for at least a year of equipment operation, then the new data is overwritten over the old ones. Practice has shown that to comply with this requirement, a card memory capacity of 8 GB is sufficient, so DOK now uses just such cards. A set of two radio relay stations requires two Industrial Temperature microSD UHS-I memory cards, because a card is placed in each of them.
PPC-10G radio relay station housing, module with Kingston industrial memory card. Source: DOK LLC
A network engineer or administrator of a telecom operator periodically downloads logs from a memory card via FTP or views them in the web interface. In this way, statistics on channel capacity and the stability of the internal components of radio relay stations are assessed. Information from logs is especially important in the event of equipment failure or its transition to a reduced data transfer rate.
Using information from logs provided by the customer, DOC technical support specialists can diagnose the problem and suggest the fastest way to resolve it. For example, having seen that the level of the received signal (RSL) has changed from a certain moment, we can conclude that, most likely, the pointing of the antennas at each other has βgotten wrongβ. This sometimes happens after hurricane-force winds or ice falling onto the antenna from the upper structures of a telecommunications tower.
Telecom operators, when purchasing fairly expensive 10-gigabit radio relay equipment, count on high reliability of all its components according to the βset it and forget itβ principle. The memory card is no exception here. An important factor here is the difficulty of accessing equipment for repair work. In the overwhelming majority of cases, radio links in the 71-76/81-86 GHz range are installed on telecommunications towers, on the roofs of buildings and structures. It is clear that climbing an icy tower in the Russian winter to replace components is not an easy and dangerous task. Although the memory card is not a critical component in PPC-10G stations, and if it fails, the radio relay line will continue to operate, but the ability to record equipment and communication channel status logs will be lost. Therefore, reliable operation of cards is important both for the manufacturer of radio links and for customers represented by telecom operators.
Close-up of a PPC-10G station module with an industrial Kingston memory card. Source: DOK LLC
βWe have been designing and producing radio relay stations in Russia for more than 10 years, and during this time we have tried memory cards from different manufacturers. Some cards worked for a year, some for a couple of years, but then we had to format them remotely, and sometimes even this did not help, which caused complaints from buyers of our equipment. When the 2016-gigabit PPC-10G model was launched into production in 10, we turned to our supplier, Superwave (St. Petersburg), for advice. They recommended Kingston industrial memory cards, saying that there would definitely be no problems with them. Since then, not a single Kingston card has failed, and we have already installed about a thousand of them. And this despite the fact that telecommunications equipment is operated year-round outdoors in very harsh conditions,β noted Daniil Korneev, director of the DOK company.
How to bypass temperature limits of memory cards and other components
If you look at the page with Industrial Temperature microSD UHS-I memory cards, you can see the limits of their guaranteed operating and storage temperature range: from -40Β°C to +85Β°C. But what to do if radio relay stations are operated in the Russian Arctic, where at night it can easily be -50Β°C or even lower? Or, conversely, somewhere in Africa?
Radio relay station PPC-10G with a Kingston memory card in the city of Tarko-Sale, Purovsky district of the Yamal-Nenets Autonomous Okrug. Source: DOK LLC
For winter conditions, the radio relay stations are equipped with an automatic heater, which ensures the temperature inside the housing above 0Β°C even in severe frosts. In the case of a βcold start,β by analogy with the launch of automobile equipment in the Arctic, the heater starts first. It blocks the switching on of electronic components until the temperature inside the station case rises to an acceptable limit.
We now go to the upper limit of the temperature range. Considering that each of the manufacturers, including Russian ones, strives to sell their radio links all over the world, the equipment must work normally even under the scorching rays of the sun. For the tropical modification, an expanded system of radiators is installed in DOK stations, distributing heat throughout the equipment body.
The PPC-10G radio relay station (with a Kingston memory card, of course) is being installed on a high-rise building in the Emirates. Source: DOK LLC
βAs a comment on Kingston memory cards, I would like to note that the lower storage temperature limit of -40Β°C in their specifications is given with a large margin. It has repeatedly happened to our customers from the northern regions of Russia that radio relay stations were turned off at lower temperatures, and we have never recorded a failure of memory cards when the equipment was subsequently turned on. As for the upper temperature limit, the temperature logs inside the case, which we again receive from Kingston memory cards, did not show exceeding the +80Β°C level for radio links in the Middle East. So the fears that the sun would heat the stations and their components above the permissible limit for our customers in Riyadh or Ajman turned out to be unfounded,β Daniil Korneev expressed his opinion about the memory cards.
This is an interesting case for memory cards Kingston Industrial Temperature microSD UHS-I provided us with . We hope to continue publishing case studies from industry and science on various Kingston products soon.
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Source: habr.com