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Providing communications of moving objects and tools to increase its reliability

I would very much like to give a lot of useful background information on this issue in this article, including reviews of scientific and practical research.

So, suppose we set off on a military convoy. According to the regulations, one of the essential attributes of this set of measures is the need to equip all vehicles of the column with high-frequency communications within one local network.

OPK, a member of Rostec, introduced the first digital generation radio station MO1 of the 6th generation back in 2016 (Software Defined Radio - SDR), which has cognitive properties. For a better understanding, we list the main ones.

The cognitive property (or the ability to learn and self-learn) implies the ability of a radio system to solve the following problems:

  1. Assessment of the so-called noise temperature of the radio environment, detection of radio frequency bands that are not currently used;
  2. Analysis of the parameters of the radio channel, estimation of channel information, prediction of the state of the radio channel;
  3. Radiated power control and dynamic spectrum control.

For a better understanding: the weight of the station is approximately 3.8 kg, in addition, the data transfer between the two stations does not require repeaters and eliminates the presence of “dead zones” for communication lines up to 600 km long. At the same time, it is able to conduct stable data transmission at a distance of 6300 km.

Serial production of the MO1 radio station began back in 2017 and today such (these and similar) stations make up about 70% of the equipment of power structures.

2017 was also marked by the adoption of the portable radio station "R-187P1 AZART", which is also the 6th generation station and allows the use of various protocols and software, amenable to training and expanding functionality.
Of the bright features of the radio station, a frequency change every 45 microseconds can be noted.

A little about the "stuffing"

The data transfer protocols in radio stations of a cognitive type, as mentioned above in the properties, amaze with their ability to adapt to circumstances in real time.

OS-MAC (Opportunistic Spectrum MAC - protocol with device)to RFS, which divides the secondary users of SU into several groups. The radio channel or radio channels used by the SU group can dynamically change depending on the state of the RFS and the state of channel availability of the entire cognitive system. The OS-MAC protocol offers a non-cooperative mode of interaction between SU ​​and PU, i.e., in fact, the almost complete absence of such interaction. With this model, the RFS is first probed in order to determine the possible behavior and operation mode of the PU. Next, a channel resource for SU is allocated, which to a certain extent takes into account the requirements of this group of users. Once the channels are allocated, SU begins to use them. The main disadvantage of this approach is that only the initially allocated channel resource meets the requirements of SU. Next, the allocation of the channel resource,corresponds to the standard pattern specified during the initial distribution of the RFS. Such patterns are generated from the geolocation database to determine the location of the PU and SU, the patterns are not rebuilt in real time.

HC-MAC (Hardware-Constrained MAC – - MAC-) , use the method of clustering (k-means), which provides the best approximation of data obtained from the outside, to track unused RF channels with high accuracy. Once free channels are detected, the SU can start using them. The HC-MAC protocol takes into account the hardware limitations of the devices, including limitations on the technical capabilities of RFS sensing and restrictions on the transmission rate in the working channel. However, if a group or single SU finds unused RF channels, while their neighboring SU groups do not receive a request to send RTS (Request to Send) / send permission CTS (Clear to Send - send permission ) data in the same channel, the first SU group cannot determine exactly which of the channels will be guaranteed to be available in the near future.As a result, collisions and interference may occur in working with neighboring SU groups or a single SU.

The Cross-Layer Based Opportunistic MAC (Cross-Layer Based Opportunistic MAC) provides two methods for sensing RFS: random sensing and probing based on a survey of neighboring nodes. The cross-level interaction protocol uses the technology of conditional “bonding” and “separation” by multiplexing to transmit data over several channels. In this paper, we propose the search for the optimal combination of bandwidth and delay in the channel, which allows us to control the quality of service QoS (Quality of service) based on cognitive radio. However, the CO-MAC method focuses on the exchange between the SU pair. Another drawback is the lack of justification for the campaign according to the criterion “cost - effectiveness”.

In the Carrier Sense Multiple Access MAC (Carrier Sense Multiple Access MAC) protocol , each SU node maintains a list of preferred channels for each of its neighboring SU nodes based on the history of interaction with these nodes. This allows you to choose your own working channel without conflict, in the sense of history, with neighboring nodes. However, storing the entire list of available channels on SU devices is inefficient, therefore, it is proposed to use a special algorithm to create lists of neighbors and exchange relevant information between them. The disadvantage is that this protocol requires a significant amount of time for exchange and is suitable for a small group of RES SU.

In 2019, Zuev A.V., Leading Engineer of Analysis and Processing of Quality Indicators of the Mobile Network of LLC Huawei Technologies Services. A new type of data transfer protocol was proposed, based on the auction model using simulation-statistical modeling.

Let's go back to the column.

In case of equipping each object with a 6th generation radio station, a local radio network is formed, which is designed to provide high-quality communication even in very rough terrain without the use of relay systems.

However, even with such equipment, there are still a number of key characteristics that are taken into account when developing a plan for the complex of such an event as the passage of a convoy (military or civilian, with or without accompaniment):

  1. , ;
  2. ;
  3. ;
  4. .

In the case of the necessary confidential communication between the cars in the columns and the scheme for increasing its reliability, studies were carried out on the use of cargo copters and various types of relaying, and one of the schemes used a modern positioning system based on a video camera. A version of a video information processing system is provided.

Based on the studies, for the implementation of high-speed confidential communication in the convoys of vehicles, relaying in “passive” and “active” systems is applicable, using quadrocopters, with perfect stabilization.

With the “active” option of relaying, 1 transmitter and 1 receiver of the AOLS system are provided and the total weight of the equipment is about 20 kg. Accordingly, the use of a light drone with this option is impossible.

In the “passive” version with mirror reflectors, the payload weight is significantly reduced and “light” type copters can be used. This also reduces the cost of providing a set of measures. On the issue of efficiency: when using mirrors with metal spraying, the reflection coefficient can be higher than 97%, and when using multilayer dielectric mirrors, the reflection coefficient can exceed 99%.

One of the prerequisites for ensuring perfect communication using the copter is the use of a drone with a 6-axis gyro system.

The 6-axis system has pitch, roll and yaw sensors, as well as an accelerometer that allows you to calculate the required acceleration in various directions. In other words, the drone will be able to compensate for the gusts of a strong wind and almost instantly take a stable position. In addition, the 6-axis gyroscope independently detects the incorrect position of the copter in the air and signals when the copter falls. Thanks to this, the pilot can even out the sticks, increase the speed and stop the fall. This option saved a lot of expensive devices from damage.

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So, getting into conditions of very rough terrain, the condition of “direct visibility” between the initial and final objects of the column, as a rule, is not fulfilled. To implement high-speed communications, quadcopter relay comes to the rescue. The conducted experimental studies have shown that the smallest fluctuations in the angle of inclination of the laser radiation, with a mirror-type reflector, can be realized on the DJI Mavic Pro Platinum quadcopter. It should be noted that on routes with a length of ~ 60–80 m, the diameter of laser radiation in AOLS systems in the receiver plane, as a rule, does not exceed 30–40 cm. Despite the relatively small divergence of laser radiation, high-speed communication in the column can be realized by installing radiation receivers, for example, on the roof of the cab of each car.At the same time, the distance between the cars in the scheme: transmitter - receiver, can be determined in several ways. 1) Using the camcorder on the quadrocopter itself. On the roof of each car put its serial number in the column. In the columns of ordinary cars, as a rule, the distance between cars is rigidly maintained, for example, 10-12 m, not to mention military columns. The length of each car in the column is also known to within a few cm. Then the distance between, for example, car No1 and car No28, using information from the copter’s camera, and knowing its height above the column, is found from simple geometric formulas.as a rule, they maintain a tight distance between vehicles, for example, 10-12 m, not to mention military columns. The length of each car in the column is also known to within a few cm. Then the distance between, for example, car No1 and car No28, using information from the copter’s camera, and knowing its height above the column, is found from simple geometric formulas.as a rule, they maintain a tight distance between vehicles, for example, 10-12 m, not to mention military columns. The length of each car in the column is also known to within a few cm. Then the distance between, for example, car No1 and car No28, using information from the copter’s camera, and knowing its height above the column, is found from simple geometric formulas.

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2) To improve the reliability of communication, recently developed, modern positioning systems using a video camera and parking lights of a car can be used.

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The side lights of the vehicle, the distance to which is measured, are indicated by (L1, L2) - at the distance DOO` and (L1, L2) - at the distance DON, respectively, from the center of the camera on the test vehicle. The DON distance is calculated from geometric relationships. At the same time, the difference in lengths between the rear position lights of the car - screen - DL`, DL, at appropriate distances, is determined in the pixels of the video camera with high accuracy.

A variant of the image processing scheme of the video camera used in the measuring system: [ Video frame

] - [Grayscale conversion] - [Contrast gain] —- (a) .-— [Binarization] - [Output length D l] —- (b) -— [Center points L1 and Extract L2] - [Extract contour] - [Processing morphology]

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