Yota network jammers
A few years ago, when we were still broadcasting WiMAX on our frequencies (our range is 2.5-2.7 GHz), a wave of articles swept the Internet on the topic of Yota wireless Internet jammers. One event spurred them - the appearance of the Crab device on the market (even their website has not changed since then). This is how these monsters look like:
.jpg)
It was obvious that such devices would sooner or later be commercially available, and this is only a matter of time. The scope of their application is also obvious - ensuring strict confidentiality at secure sites, or, worse, consciously suppressing the capabilities of wireless Internet by landlords of business centers interested in promoting the services of their court providers. But the impact of these devices on our network was not obvious to us. Indeed, it is one thing when this device jamming a signal within a special room, and quite another thing when subscribers within the adjacent territories and in neighboring houses are affected. And it was even more important to understand whether the roof of base stations under the influence of such an anomalous signal would not go.
')
The fact is that in the base stations there are synchronization modules that work over the air. Violation of their work can disrupt the performance of the base station, and in some cases its “neighbors”. Everything said that there should be no problems on the network equipment, but who knows what unknown "hidden features" are protected in the WiMAX base stations, and the operational documentation reveals not all of the similar nuances of their livelihoods. The case of LTE technology with its “smart” features like ANR, MRO, COD, etc. deserves separate consideration, but more about that later.
Actually, the only way to check our fears was to get this device. However, this was not so easy to do. The guys who made it went underground after a wave of articles and unhealthy activity around their device. With great difficulty, having invented a legend for myself (a whole espionage story), I came in contact with them and as a result I acquired the device for testing.
We had several days to check everything and draw conclusions. Of course they started from the lab. The device turned out to be quite powerful and really hammered the entire frequency range used. At the same time, his long-term work did not affect the work of the base station, which could not but rejoice. However, it was a laboratory and, as is known, it differs from a combat network in its ideal conditions. Therefore, it was decided to transfer the tests to the fields.
For field tests, we chose the weekday and the time of the least activity of subscribers (about 4 o'clock in the morning). We were divided into two groups: the first group was to settle in our business center and turn on the device, the second - with the measuring equipment, bypass the area around and check the level and quality of the signal. Conceived - done!
The test results impressed. The power of the device was enough not only on the territory of the business center, but also on the nearby houses. The signal really was within our range and did not affect the overhead sync bands. In houses, the signal degraded significantly, the network found a modem, but did not connect. The operation of the device for two hours did not show any visible effect on the base stations, but two hours was too little to draw any serious conclusions, and we could not delay the testing and deprive subscribers of the service. At this testing, it was decided to finish.
Device returned. Most worried about his power. After talking with the developers again, we found out that it can be changed by agreement with the customer. And it seems that even these guys later reduced the base power on the manufactured devices, so as not to create a large influence on the territories adjacent to their use. But how many more of these underground producers of this "good"?
Despite the fact that this story is already several years old, and now, when Yota is already working on LTE, but in the same frequency range of 2.5-2.7 GHz, we receive subscribers' complaints that somewhere then it mutes the signal of our network. We are trying to deal with these available means - we are writing letters to the appropriate authorities and in every way we are trying to influence such “pests of the air”. But it is not always possible to achieve a positive result.
In order to simplify the detection of such unauthorized activities of unscrupulous jammers, I even somehow wanted to do something like this device , but so far I did not succeed - there is not enough skill. And maybe here, on Habré there are worthy craftsmen? My kingdom for a horse!
It was obvious that such devices would sooner or later be commercially available, and this is only a matter of time. The scope of their application is also obvious - ensuring strict confidentiality at secure sites, or, worse, consciously suppressing the capabilities of wireless Internet by landlords of business centers interested in promoting the services of their court providers. But the impact of these devices on our network was not obvious to us. Indeed, it is one thing when this device jamming a signal within a special room, and quite another thing when subscribers within the adjacent territories and in neighboring houses are affected. And it was even more important to understand whether the roof of base stations under the influence of such an anomalous signal would not go.
')
The fact is that in the base stations there are synchronization modules that work over the air. Violation of their work can disrupt the performance of the base station, and in some cases its “neighbors”. Everything said that there should be no problems on the network equipment, but who knows what unknown "hidden features" are protected in the WiMAX base stations, and the operational documentation reveals not all of the similar nuances of their livelihoods. The case of LTE technology with its “smart” features like ANR, MRO, COD, etc. deserves separate consideration, but more about that later.
Actually, the only way to check our fears was to get this device. However, this was not so easy to do. The guys who made it went underground after a wave of articles and unhealthy activity around their device. With great difficulty, having invented a legend for myself (a whole espionage story), I came in contact with them and as a result I acquired the device for testing.
We had several days to check everything and draw conclusions. Of course they started from the lab. The device turned out to be quite powerful and really hammered the entire frequency range used. At the same time, his long-term work did not affect the work of the base station, which could not but rejoice. However, it was a laboratory and, as is known, it differs from a combat network in its ideal conditions. Therefore, it was decided to transfer the tests to the fields.
For field tests, we chose the weekday and the time of the least activity of subscribers (about 4 o'clock in the morning). We were divided into two groups: the first group was to settle in our business center and turn on the device, the second - with the measuring equipment, bypass the area around and check the level and quality of the signal. Conceived - done!
The test results impressed. The power of the device was enough not only on the territory of the business center, but also on the nearby houses. The signal really was within our range and did not affect the overhead sync bands. In houses, the signal degraded significantly, the network found a modem, but did not connect. The operation of the device for two hours did not show any visible effect on the base stations, but two hours was too little to draw any serious conclusions, and we could not delay the testing and deprive subscribers of the service. At this testing, it was decided to finish.
Device returned. Most worried about his power. After talking with the developers again, we found out that it can be changed by agreement with the customer. And it seems that even these guys later reduced the base power on the manufactured devices, so as not to create a large influence on the territories adjacent to their use. But how many more of these underground producers of this "good"?
Despite the fact that this story is already several years old, and now, when Yota is already working on LTE, but in the same frequency range of 2.5-2.7 GHz, we receive subscribers' complaints that somewhere then it mutes the signal of our network. We are trying to deal with these available means - we are writing letters to the appropriate authorities and in every way we are trying to influence such “pests of the air”. But it is not always possible to achieve a positive result.
In order to simplify the detection of such unauthorized activities of unscrupulous jammers, I even somehow wanted to do something like this device , but so far I did not succeed - there is not enough skill. And maybe here, on Habré there are worthy craftsmen? My kingdom for a horse!
Source: https://habr.com/ru/post/182082/
All Articles