RU2336635C1 - Short-wave radio communication network for discrete message transfer - Google Patents

Abstract

FIELD: physics, communication.

SUBSTANCE: invention concerns short-wave radio communication systems and maintains double-way user communication over remote base retransmitters. To achieve this objective, network consists of base retransmitters remote from users and interconnected by base retransmitter communication lines enabling double-way communication between network users by receiving group signal compressed in time from users sending messages, and by transmitting these messages to target users in time sequence; and receiving centers distributed over some area and connected to base retransmitters by communication lines.

EFFECT: maximum possible reliability of message transfer by low-capacity user transmitters in short-wave radio communication network with remote base retransmitters.

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Description

The invention relates to short-wave radio communication systems and provides two-way communication of subscribers through remote base repeaters.

For stationary and moving objects, hereinafter referred to as subscribers, located at large distances from each other and located at a considerable distance from large settlements served by cellular communication systems, there are two options for two-way radio communication: satellite and short-wave (HF) radio communications.

Despite the intensive development of satellite communication systems, the use of HF communication systems as a means of transmitting information continues to be very relevant in connection with their capabilities, which allow for low-cost communications to organize communication at virtually any distance when other types of communication are absent or stop working due to emergency circumstances.

The advantages of HF communication systems also include the efficiency of long-distance communication, the ability to provide communication with subscribers in hard-to-reach areas, including in the mountains, the high mobility of communication facilities, the relatively easy call recovery if it is interrupted as a result of both random and and intentional interference, as well as the low cost of transmitting information. KB communication is of particular importance in emergency situations - when organizing and conducting emergency rescue operations, coordinating the actions of various services in areas of natural disasters, etc.

There are various options for the construction of zone systems of short-wave radio communications with remote relay points:

- in the adaptive short-term subscriber telegraphy relay system (RASKAT), an option is proposed to provide short-wave radio communications to subscribers throughout Russia and the CIS using three ground-based relay points, each of which serves two zones with a width of about 1.5 thousand km;

- in the interzonal territorial radio communication system (MESON), which is the development of the RASKAT system, the ability to send messages to subscribers located in different territorial zones is provided;

- ASTRA system - an automated telegraphic radio communication system with signal relaying - provides communication in an extended zone with a radius of up to 3.5 thousand km due to several relays located around the circumference of the zone (Golovin O.V., Prostov S.P. Systems and devices short-wave radio communications. - Hot line. - Telecom, 2006, p. 54-65).

The operation of the RASKAT system and its modifications is characterized by single-channel radiation from the subscriber, the formation of a group spectrum on the air, group reception in a repeater, signal processing, the formation of a group spectrum and its radiation in a repeater, individual subscriber reception of a signal in a channel allocated to it, to which the receiver is automatically tuned.

However, these communication systems are characterized by the following disadvantages:

- the use of a group signal by the transmitter of the repeater leads to the fact that the signal emitted by the transmitter has a relatively large peak factor, which reduces the efficiency of the transmitter;

- the use of a minimum manipulation speed of 50 baud is not enough, since the power of subscriber transmitters can be units of W, which does not allow for reliable reception of messages by repeaters from moving objects;

- allocation of separate operating frequencies to separate zones requires an extremely large number of them and additional hardware, which complicates and increases the cost of the communication system.

Closest to the proposed invention is the HF communication system MARS - mobile automatic radio communication between objects that can be located throughout the Eurasian continent. This system uses a limited number of repeaters remote from interacting subscribers and is characterized by high reliability of message transmission, economical use of the frequency resource, and ease of implementation (Khazan V.L. MARS Decameter Mobile Automatic Radio Communication System // Radio Communication Technology. NTS, issue 4, Omsk 1998, pp. 59-66, prototype).

In this communication system, the above drawbacks are absent and special measures have been taken to increase the reliability of communication when sending messages from the subscriber to the remote repeater, namely, all subscribers continuously alternate oblique sounding of all communication channels by the transmitted signals from the relays with an individual quality assessment of each of them and Autoselect the most highly reliable at the current time. In addition, the message is transmitted by the subscriber radio station at the maximum permissible low speed of 4-5 baud, which ensures the maximum achievable signal / noise ratio when receiving these signals, and the signals are transmitted with frequency shift keying at the largest possible frequency deviation (3000-9000 kHz) and receiving subcarriers of these signals on the base repeater is carried out individually, as two frequency-spaced amplitude-manipulated signals, which allows to obtain additional energy gain 1 0-30 dB.

The technical result, the achievement of which the present invention is directed, is to provide the highest possible reliability of message transmission by low-power subscriber transmitters in the KB radio network with remote base transponders.

In order to achieve such a technical result in a shortwave radio communication network for transmitting discrete messages at any distance within the service area, consisting of remote relays remote from the subscribers and interconnected by communication lines, providing two-way communication between network subscribers by receiving a group signal from the message transmitting subscribers frequency multiplexing and transmission of these messages to their recipients sequentially in time, additionally establish territorially Assigned receiving centers connected by communication lines with basic repeaters.

The distinctive features of the proposed short-wave radio communication network from the above known, closest to it, is the presence of additional geographically spaced receiving centers and their connection with the base repeaters by communication lines, which ensures maximum decorrelation of both received fading signals and station interference at diversity points, unlike conventional spatially diversity reception. Additional receiving centers in the amount of N are located in the area of the base repeater around it and at a distance of up to 500 km from it.

Each additional receiving center is connected to its repeater by external communication lines (wired, microwave, satellite, etc.). Due to the geographically dispersed reception of signals, it is possible to significantly increase the reliability of the transmission of messages from the subscriber to the side of the remote repeater.

Figure 1 shows the structural diagram of a short-wave radio network for transmitting discrete messages with repeaters and additional receiving centers remote from subscribers, which can serve the entire territory of Russia (six basic repeaters located, for example, in the following cities: Volgograd, Ufa, Omsk, Krasnoyarsk , Ulan-Ude, Blagoveshchensk).

The diagram indicates:

BR _j - j-th basic repeater;

Pr _nj - additional n-th receiving center at the j-th basic repeater;

And _i is the i-th subscriber.

Many subscribers located between subscribers with indices are indicated by gray circles in the diagram.

The network operates as follows.

Periodically, for example, once an hour, all subscriber radio stations automatically inform the base repeaters of the signals that they receive with the highest quality rating, their addresses. Each basic repeater directly or through one or more of its own additional receiving centers receives these messages. Thus, all basic repeaters have a complete list of the subscribers they serve. All basic repeaters exchange this information with each other. If now the subscriber A ₁ , which is served by the base relay BR ₂ , wants to send a message to the subscriber A _k , which is served by the base relay BR ₅ , then there is no need for all the other base relays to participate in the transmission of this message. Basic relay BR _2, taking the next message from the user A _1, either directly or through one or more of its own additional reception centers for external communication lines forwards the message to the base repeater BR _5, and the latter is already causing to communicate subscriber A _k and transmits addressed to the subscriber a message . Having received a receipt from the recipient, confirming the reliability of the delivery of the message sent to him, the BR ₅ base relay sends the receipt to the BR ₂ base relay via external communication lines, which delivers it to the message sender, subscriber A ₁ . The message transfer cycle ends here.

Example. Communication conditions provide the probability of the transmission of the message P ₁ from the subscriber towards the base relay. The probability of unacceptability of the message P ₀ in this case is equal

If we assume that the conditions for receiving signals from the subscriber in the entire area of additional receiving centers are approximately the same (but mutually independent), then taking into account (1) the probability P _{0 (1 + N) of} simultaneous reception of the message by the relay and all N additional receiving centers will be equal to

From (2) it follows that the probability P _{1 (1 + N) of} receiving a message by at least one receiving center of N or a relay will be equal to

Figure 2 shows a graph of the dependences of the probability of receiving a message on a subscriber - base relay communication channel with N additional receiving centers surrounding the relay and territorially spaced from it at a distance of 100-500 km, from the probability of receiving a message on a subscriber - base communication channel repeater "without additional geographically spaced receiving centers.

The graph shows that in case of poor communication conditions, when only 40% of messages are transmitted on a single channel, the presence of eight additional receiving centers increases the percentage of received messages to 99%. If 50% of messages are transmitted on a single channel, then six additional receiving centers provide reception of more than 99% of messages. Under communication conditions, which are considered satisfactory in the KB band, when 70% of messages are transmitted through a single communication channel, the presence of only three additional receiving centers raises the percentage of received messages to 99%.

Known are shown in figure 3, the dependence of the values of the transmitter power, providing a given reliability of receiving messages, on the length of the path, obtained experimentally Konopleva E.N. ("On the calculation of the reliability of communications at short waves." Telecommunications, 1967, No. 11). Comparing the reliability curve corresponding to 50% with the reliability curve corresponding to 99%, we can see that the energy costs for switching from the first level of reliability to the second are about 43 dB, that is, about 20,000 times in power. This kind of energy gain comes from six additional receiving centers.

Thus, given that the cost of a limited number of receiving devices is much less than the cost of the entire fleet of subscriber transmitting devices having a power of 10-100 W, it is economically advantageous to increase the reliability of message transmission in the KB communication network not by increasing the power of subscriber transmitters, but by placing additional receiving centers located in the areas where the base transponders are located, connected to these transponders by communication lines (wired, radio relay, satellite, etc.).

Claims (1)

A short-wave radio communication network for transmitting discrete messages, consisting of base repeaters remote from the subscribers and interconnected by communication lines, providing two-way communication between the network subscribers by receiving a group signal with frequency multiplexing from the transmitting message subscribers and transmitting these messages to the subscribers receiving them sequentially in time, characterized in that the network contains additional geographically dispersed receiving centers associated with their base transponders shnimi communication lines, and designed to increase the reliability of transmission of messages from the subscriber to the side remote from it the base repeater.

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