RU2382499C1 - Method for radio communication between mobile objects - Google Patents

Abstract

FIELD: physics; communication.

SUBSTANCE: invention relates to radio communication systems with multistation access. The method for radio communication between mobile objects (MO) is characterised by that, an information unit containing data is transmitted from a central mobile object and received at a mobile object. Data from sensors of the mobile object (CMO) are transmitted to the central mobile object. During the time of a single frame, there is simultaneous pairwise two-way radio communication of each mobile object with each mobile object including the central mobile object. During each time window of duration T₀, there is simultaneous pairwise narrow-directed two-way information exchange between half of the mobile objects which are registered in the radio network at the present moment. On each mobile object there is majority processing and subsequent decoding of information messages received from other mobile objects. Frames and time windows are synchronised in accordance with a given formula.

EFFECT: increased security, noise-immunity and communication reliability.

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Description

The invention relates to radio communication systems with multiple access.

Known methods of radio communication with moving objects (software) are used in air traffic control systems. The method of radio communication with software [1] is that when exchanging information with software located in the coverage area of the central station (CA), an information block containing the address of the peripheral station is transmitted from it to the peripheral mobile stations at a frequency f ₁ . If the address of the peripheral station and the address transmitted from the DS from the peripheral station at a frequency f ₂ coincide, an information block is transmitted to the DS. From time to time, a clock signal for all peripheral stations is transmitted from the DS to a frequency f ₃ . Using this signal, at each peripheral station, a number is randomly selected from a finite set of integers indicating the number of the response interval, in which its address is sent to the central frequency on frequency f ₄ from the peripheral station, after which the confirmation signal is transmitted on frequency f ₃ after undistorted reception reception. In the case of a distorted reception of the address, an acknowledgment signal is not transmitted, and at the peripheral station, the choice of the response interval number is repeated until confirmation of the correct acceptance of the address is received. After that, the peripheral station operates at frequencies f ₁ , f ₂ during an information exchange session with the CA. At the end of the exchange of information, the peripheral station switches to work at frequencies f ₃ and f ₄ . The clock signal is transmitted in the form of an encoded signal representing the address of the CA.

The disadvantages of this invention are the need for four software transceivers simultaneously; the presence of a signal periodically emitted from the CA at a frequency of f ₃ , which worsens the electromagnetic environment in the radio communication zone, as well as a complex data exchange algorithm between the CA and the software.

The closest analogue, selected as a prototype, is a method of radio communication with software [2], which consists in transmitting from the central office a block of information containing the data embedded in it, receiving it on the software and transmitting from the software an information signal containing confirmation of the receipt of the information block with The DS and the data from the sensors of the moving object, delayed relative to the information block received from the DS, enter code groups of the type of work of the type of requested data, the nominal frequency of the operating frequency for the next exchange frame, and into the information block with the DS the belt of the beginning of the next frame, the data in the information signal from each of the software is distributed over time intervals, depending on the number determined by the code group of the type of work, starting from the time specified by the code group of the start time of the next frame, the time synchronization between the CA and the software is carried out using the global navigation system timeline, the frame duration T is determined based on the purpose of the radio communication system, but not more than

T = (1 + Nn) τ + t for τ≥mδ _t ,

where N is the number of software;

n is the number of bits in the message with the software;

t is the maximum total time of propagation of the radio signal on the line "DS - ON - DS" and twice the duration of the message from the DS;

σ _t is the relative standard error of the determination of the current time interval;

τ is the duration of a single transmission of information;

m is a coefficient (greater than unity), depending on the purpose of the radio communication system.

The disadvantages of the prototype are:

- the need to transmit for the next frame the nominal of the operating frequency and the start time of the next frame, which reduces the reliability of communication in case of failure to deliver this information to the software;

- the need to ensure mutual synchronization according to the signals of the timeline of the global navigation system GPS or GLONAS, which reduces the reliability of communication in case of failure or suppression of the signals of the GPS or GLONAS system;

- the organization of the radio network is carried out by the CA at a fixed frequency f ₁ , which reduces stealth, reliability and noise immunity;

- the number of the time interval in the frame is determined on each software using the code group of the type of work received from the CA, which disrupts the radio network if this code group is not accepted on the software;

- the use of the simplex mode of information exchange leads to the need to take into account the doubled propagation time of radio signals, while in the duplex mode only single;

- the use of omnidirectional antennas in the communication system reduces spatial stealth and does not allow the organization of the exchange of each software with each software;

- lack of information exchange of all software with each other reduces the reliability of communication;

- noise immunity is reduced due to the impossibility of using methods of reception spaced in space, time and frequency and the absence of majority processing of information on each software;

- when switching the operating frequency, an introduction of the Tsint synthesizer switching time into each clock cycle is required, while the message transmission time will increase by a factor of K

K = (Tsint + τ) × n / τ × n = 1 + Tsint / τ, (times),

where Tsint is the frequency switching time in the synthesizer;

τ is the duration of a single transmission of information;

n is the number of bits in the message.

The transmission speed will decrease by the same amount. With increasing transmission speed, i.e. a decrease in τ and a constant value of Tsint, the loss in increasing the transmission rate of useful information will increase.

The objective of the invention is to increase the secrecy, noise immunity and reliability of communication.

The indicated technical result is achieved by the fact that a block of information containing the data embedded in it is transmitted from the central movable object (CPO), it is received by the software, and data is transmitted from the sensors to the software from the software, code groups of the form are introduced into the information block with the CPO jobs such as the requested data, the start time of the next frame, the data in the information signal from each of the software is distributed over time intervals depending on the number determined by the code group of the type of work, starting from the time specified a single group of the start time of the next frame, characterized in that for one frame simultaneously, two-way duplex radio communication of each software with each software, including the DSP, is carried out using narrow-directional antennas, oriented according to the coordinates known on all software and DPC, for each time window of duration T ₀ is performed simultaneous pairwise unidirectional duplex communications between N / 2 oN, where N - number registered in a radio network at a given time oN, the data in each information packet, eredavaemom during the duration T _0, distributed over time positions for all software registered at any given time in the radio network, to each according to carry a majority for processing and decoding of data messages received on different paths from each other by separated in space, time and frequency, to other software transmit the initial information message entered by the CPO into the radio network at the beginning of each frame, and to the CPU send an information message from the sensors of this software to the positions of this software, on other positions initial information message, frame synchronization and time window of duration T ₀ in each ON performed by applying on each ON and ATEC highly stable reference oscillators with subsequent mutual synchronization using the sync signal transmitted at the start of each information message, the frame duration determined according to the formula :

T _c = N _3a × T ₀ + K × T ₀ = (K + N _per ) × T ₀ ,

where N _za is the number of software registered at the given time in the radio network;

T ₀ - the duration of the time window of information exchange in each pair of radio network software;

To - the number of additional windows with a duration of T ₀ for inclusion in the network of new software.

The time of information exchange in each pair of radio network software is determined based on the expression

T ₀ = tzi + tcg + type + tpch,

where t _zi is the guard interval equal to tз≥D _max / c, where D _max is the maximum possible mutual distance between software in the radio network, and c is the propagation speed of radio signals;

tcg is the duration of the sync group at the beginning of each information message;

type - duration of the information package;

tpch is the duration of switching from one operating frequency to another.

The operating frequency is changed in each information message according to a pseudo-random law known at each software and CPU.

On the CPU, the signals transmitted by the CPU to the radio network for all software are compared with the signals returned by each software back to the CPU and, thus, the status of the software and the communication channel with each software is determined on the CPU.

The proposed method allows for narrowly targeted radio communication in one frame between all the software of the radio network using spacings in space, time and frequency with majority processing and subsequent decoding of information by each software, which ultimately increases the noise immunity, stealth and reliability of communication.

All differences of the present invention can be divided into absolute (operations and algorithms) and relative or mutual, characterizing the interaction between absolute differences (relationships between individual operations and algorithms).

In the proposed method, differences of the absolute type (spacing in space, time, frequency and majority processing) are known from the technical literature [3, pp. 225-229]. However, in known solutions, they do not contribute to the provision of radio communication between all software in one frame.

As for the differences of the mutual type, i.e. new connections, they are absent in the literature.

To explain the implementation of the method, the following drawings:

Figure 1. Diagram of the process of disseminating information in a group consisting of six software with TT1 = 6T ₀ and seven software with TT2 = 7T ₀ .

Figure 2. Relationship diagram in a group of six software in steady state.

Figure 3. The cycle diagram of the spatial, temporal and frequency separation of six software and the temporary structure of the information exchange window with each software.

Figure 4. An upper estimate of the probability of information delivery on a radio network depending on the probability of delivery in each partial channel.

The method of radio communication with software is implemented as follows.

At the initial moment of time T0 (see Fig. 1), determined by the general plan of the task, known at all software and CPOs, the CPO, having detected POi in its radar field and, having determined its coordinates, carries out the electronic orientation of the radiation pattern of its antenna system to the given POi and POi, knowing the coordinates of the CPO from the general plan of the task, known on each software, by loading it into the database of these software before the task carries out electronic orientation of the radiation pattern of its antenna system to the CPO. Further, the CPO at the frequency F1, determined by the pseudo-random law of frequency formation, known at each software and CPU, in the time window T0 transmits POi information packet (IP) at the frequency F1, containing its address, the address of this software, the addresses of other software previously registered in the radio network , the number of the time window in which this software will carry out information exchange with the CPO, the position number of the control information for this software, the coordinates of the CPU and all the necessary service information for the organization of its work in the radio network, as well as similar and formation for other software registered at any given time in the radio network. POi at a frequency of F6 in the same time window T0 transmits the IPO CP containing its address, CPO address, telemetry information from its own sensors (speed, altitude, geographical coordinates, etc.). The CPO compares the received addresses with the addresses stored in the database of its central computer (CEC), and the speed, height, geographic coordinates and other parameters of this software are compared with the ones measured by the CPO radar and the parameters of this BY. If all addresses match, and the coordinates and other parameters received from this software do not go beyond the tolerances, then the CPU registers this POi in its radio network. The registration operation described above is always carried out in the window T0 of each frame for each software that appears in the radar field of the CPO. Further, the CPO switches the transmission frequency from F1 to F3, and the reception frequencies from F6 to F4 in accordance with the law of changing operating frequencies and simultaneously carries out electronic reorientation of the radiation pattern of its antenna-feeder system to PO1, which was previously registered in the network and which for information The exchange was given this time window. PO1 performs similar operations at home. In the time window T1, an information pair exchange is carried out between the CPO and PO1, as well as between other pairs registered in the radio network at other transmission and reception frequencies. In this information exchange, the CPO transmits PO1 control information for all the software currently registered in the radio network, and PO1 transmits the CPO its information and information previously received from other software. A similar information exchange is carried out within each pair. For a full frame, information exchange is carried out between all software registered in the radio network, and each software has the same information of the entire time window will be repeated at least N / 2 times. As the information of the entire time window of each software is repeated, the digital processing unit of each software carries out majority processing of the received information, for example, according to the N-2 principle from N-1 and its subsequent decoding. As an example, we can consider the situation with a 3-fold repetition and a solution of 2 out of 3, or with a 4-fold repetition and a solution of 3 out of 4, etc. In the next time window, the software that made the majority decision in the previous time window transfers this decision after decoding to another software. Similar processes occur in the frame of TC2.

Let us consider the method of radio communication between software using a specific example of a radio network consisting of six software.

The total number of pairwise connections between all six software is 15 and is determined by the expression

- число комбинаций i по n.Where

is the number of combinations of i over n.

The number of pairs among six software is 6/2 = 3.

Out of all possible 15 bonds, at the same time pair bonds can be in the whole expression no more than three

These three simultaneous connections between the software are provided by the directional antennas of these software. In figure 2, the symbols in the form of radiation patterns show how it is possible to organize the simultaneous information exchange of three pairs for six currently registered software in the radio network.

Consider in detail the cadrogram of information duplex communication, presented in figure 3 for six software. The cadrogram consists of six time windows of pairwise exchange between software. The time intervals of pairwise exchange are sectors indicated by the windows T0, T1, T2, T3, T4 and T5, respectively. The operating frequencies at which the information exchange between the software is carried out are presented in the form of rings, inside which the frequencies F1, F2, F3, F4, F5, F6 are written.

Figure 3 in the form of three nested into each other concentric circles corresponding to different operating frequencies F1-F6, schematically shows three simultaneously existing cadrograms of pairwise information exchange in the group. Inside the segments, software numbers (for example, 3, 4) are indicated, between which in this time window (for example, T1) at frequencies F1-F6 a duplex information exchange between PO3 and PO4, PO2 with PO5 and CPO with PO1 is performed. Various arrows show the process of switching the operating frequencies of each software. The outgoing ends of the arrows indicate the number of software operating in this time window at its own frequency (for example, in window T1, software 3 transmits at frequency F1 software 4, and software 4 transmits at frequency F6 software 3). The descending ends of the arrows indicate the same software that in the next time window T2 switches to a different transmission frequency (for example, in window T2, PO1 transmits at frequency F2 PO3, and PO3 transmits at frequency F5 PO1). To implement mutual time synchronization between all software, highly stable reference generators on each software are needed. The stability of these generators is selected in such a way as to ensure mutual divergence of not more than the duration of the sync group (SG) during one frame.

Analysis of the cadrogram of the time-frequency separation of six software shows that for a time interval equal to six time windows, all six software will exchange information with each other.

The temporary structure of the information exchange window of each software is presented in the same figure 3.

Consider the structure of a time window of duration T ₀ in FIG. 3 and the purpose of each component for the implementation of information exchange in the group:

- ZI - guard interval, this is the time equal to the longest signal propagation time between the software in the range of mutual distances;

- SG - a sync group necessary to ensure mutual synchronization of software between which communication is performed in a window;

- IP - an information package that carries information from one software to another software, is necessary for information exchange between software;

- IF - the time required to switch synthesizers from one operating frequency to another to implement frequency separation between software.

Consider in more detail on the example of a group of six software the process of establishing the transfer of information from software to software, presented in figure 1 in the frame TC1. A feature of this method of transferring information between softwares is that each software receives information for all software during the exchange process (hereinafter simply information). At the central processing center, each software transmits information from its sensors at its temporary position, and during the exchange between the software, information transmitted from the central control center.

In the time window T0, the CPO receives new software into the radio network. The process of transmitting software information registered in the radio network begins with the CPO, which in the time window T1 transmits information software1, which is stored by software1 in its memory, and receives information from software1, which also stores it in its memory for the first time, the number of retries (saves) k is indicated by the numbers in FIG. 1. In the time window T2, PO1 transmits information PO3 and receives information from PO3, and the CPU transmits information PO2 and receives information from PO2, which is stored by each software. In the time window T3, PO1 transmits information PO5 and receives information from PO5, the CPU transmits information PO3 and receives information from PO3, and PO2 transmits information PO4 and receives information from PO4, which is stored by each software. It is easy to notice that for PO3 in the time window T3, information for all software of the radio network will accumulate 2 times (the first time it arrived PO3 in the interval T2, and the second time in the interval T3). In the time window T4, the CPO transmits information PO4 and receives information from PO4, PO3 transmits information PO5 and receives information from PO5, and PO1 transmits information PO2 and receives information from PO2, which is stored by each software. It is easy to notice that in the time window T4, the information from PO3 for all software of the radio network is accumulated 3 times, and for PO1, PO2, PO4 and PO5 it is accumulated 2 times. PO3 carries out majority processing of the accumulated information by a decision of 2 out of 3, decodes it and passes it further over the radio network. In the time window T5, the CPO transmits information PO5 and receives information from PO5, PO1 transmits PO4 and receives information from PO4 of the radio network, and PO2 transmits information PO3 and receives information from PO3, which is stored by each software. It is easy to see that in the T5 time window for PO1, PO2, PO4, and PO5, information for all software of the radio network will accumulate 3 times, and for PO3 it will accumulate 4 times. When exchanging with software, the CPC compares its initial information for the software with similar information returned from the software with which the exchange is currently taking place, the status of communication channels with each software is determined by the result of the comparison.

Thus, after the 5th time interval of information exchange, each software can majority process information at its place according to the principle of 2 out of 3 and thereby increase the reliability of information delivery. Similar processes occur in the frame ТЦ2 (see Fig. 1), and after the 6th time window, each software can majority process information at its place according to the principle of 3 out of 4 and thereby increase the reliability of information delivery.

An upper estimate of the probability of information delivery in a radio network consisting of n software is determined by the expression

where p is the probability of information delivery in each partial communication line between i and j software;

d is the degree of the vertex defined by the expression

d = 2NcB / n (for n> 2);

n is the number of software;

Ncv is the total number of connections between software.

,

,

where i = 2, since the connection is between pairs of software.

In figure 4. comparative characteristics of the probabilities of information delivery in a radio network for a different number of radio network software versus the probability of delivery in a partial channel between i and j software are given.

The analysis of figure 4 shows that with an increase in the number of software, the probability of delivery in a radio network (Pc) increases, for example, for n = 2 and Pi = 0.2, Pc = 0.05, and for n = 33 and Pi = 0.2 , Pc = 0.97, i.e. with an increase in the number of software from 2 to 33, the probability of delivery increases from 0.05 to 0.97, i.e. 0.97 / 0.05 = 19.4 times.

Thus, the technical result in terms of increasing noise immunity, stealth and reliability of communication is ensured by:

- implementation during one frame of communication of each software with each software;

- application of majority processing of information by each software of the radio network with subsequent decoding of information by each software;

- the use of diversity in space, time and frequency;

- application of narrow radiation patterns of antenna systems.

Information sources

1. Copyright certificate No. 1596468, publ. 09/30/1990

2. Patent RU No. 2231927, publ. 06/27/2004

3. Penin P.I. "Digital Information Transmission Systems". M., ed. Owls Radio, 1976, p. 365.

Claims (3)

1. The method of radio communication between mobile objects (software), which consists in transmitting from a central mobile object (CPO) a block of information containing the data embedded in it, receiving it on software and transferring software from CP to CPO, data from software sensors, to the information block code groups of the type of work, type of requested data, start time of the next frame are entered from the CPO, the data in the information signal from each of the software is distributed over time intervals depending on the number determined by the code group of the type of work, starting from the point in time set by the code group of the start time of the next frame, characterized in that for one frame simultaneously, two-way duplex radio communication of each software with each software, including the DSP, is carried out using narrow-directional antennas, oriented according to the coordinates known on all software and CPU, for the time each time window of duration T ₀ , carry out simultaneous pairwise narrowly directed duplex information exchange between N / 2 software, where N is the number of software registered in the radio network at a given time, the data in each information an ion packet transmitted over a time duration of T ₀ are distributed according to temporary positions for all software registered at a given moment in the radio network, majority processing and subsequent decoding of information messages received on different paths from other software spaced in space are performed on each software, time and frequency, to other software transmit the initial information message entered by the CPO into the radio network at the beginning of each frame, and NGOs send an information message from the sensor to the positions of this software s of the software, and the remaining positions initial information message, frame synchronization and time window of duration T ₀ in each ON performed by applying on each ON and ATEC highly stable reference oscillators with subsequent mutual synchronization using the sync signal transmitted at the start of each information message, the duration of the frame is determined by the formula:
T _c = N _za · T ₀ + K · T ₀ = (K + N _for ) · T ₀ ,
where N _for - the number of software registered at the given time in the radio network;
T ₀ - the duration of the time window of information exchange in each pair of radio network software;
K is the number of additional windows T ₀ for inclusion of new software in the network, the information exchange time in each pair of radio network software is determined based on the expression
T = t ₀ + t _{communications Cg} + t + t _{u nq,
communication} where t - the guard interval equal to t _{communications} ≥D _max / c, where D _max - maximum possible relative removal between the software in the radio network, and with - the speed of propagation of radio signals;
t _cg is the duration of the sync group at the beginning of each information message;
t _ip - the duration of the information package;
t _pch is the duration of switching from one operating frequency to another. 2. The method according to claim 1, characterized in that the operating frequency is changed in each information message according to the pseudo-random law known on each software and CPU. 3. The method according to claim 1, characterized in that the CPU compares the signals transmitted by the CPU to the radio network for all software with the signals returned by each software back to the CPU, and the status of the software and the communication channel with each software is determined on the CPU.

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