RU2636574C1 - Method for controling transmission speed and range in radio modem of adaptive radio line for transmitting discrete information flows - Google Patents

Abstract

FIELD: radio engineering, communication.SUBSTANCE: method for controlling the transmission speed and range in a radio modem of an adaptive radio line for transmitting discrete information flows is proposed, which consists in flexible change in the parameters of the transmitted information flows with the help a modulator/demodulator in which, in the initial state, the parameters of the radio line are tuned to the minimum transmission rate and the lowest frequency of the operating band, and when communication with a remote transceiver occurs, a threshold signal-to-interference ratio is determined and the radio line is transferred to a higher transmission rate or to a higher information transmission frequency by changing the settings of the modulator/demodulator, thus producing a continuous exchange of characteristics of information receiving quality between correspondents.EFFECT: providing the optimal communication speed and range by varying the frequency transmission depending on the communication conditions in the channel.1 dwg

Description

The proposed method relates to radio technology for the transmission of arrays of information in digital format.

The tasks to be solved when transmitting information over a radio channel usually include the tasks of increasing the transmission speed and increasing the range of the radio transmitter with constant power consumption. One of the methods is adaptive tuning of the parameters of the radio line depending on the parameters of the received / transmitted signal, propagation conditions, and other factors, i.e. adaptation to the conditions for ensuring the operation of the radio line.

In the patent [1], for transmitting information in a digital format, it is proposed to change the pulse shape of both the envelope and the filling frequency, which makes it possible to realize the maximum transmission speed. In the method described in the patent [2], adaptation to the propagation conditions is that the transmitted signal is approximated by a polynomial, reception errors are modeled, and then the shape of the polynomial is adapted so that reception errors are minimal.

The closest in functional characteristics to the proposed technical solution for the speed and range of transmission of a digital signal over a radio line is the method according to the patent [3], which is adopted as a prototype.

The patent [3] implements a method of independent frequency adaptation for each subchannel of a multi-frequency group signal. The application of this method allows to eliminate communication interruptions during switching frequencies of subchannels affected by noise, and thereby reduce the density of the shift flux of fixed transmission frequencies. Due to this, it is possible to increase the throughput of the radio link. To implement this method, a frequency adaptive radio link containing a receiver, transmitter, radiometric block, modulator and demodulator blocks, command encoding and decoding blocks, transmit and receive reference frequency blocks, a manipulation code generation block, transmission reference frequency switching blocks and reception.

If interference occurs in any subchannel in the patent [3], it is proposed to use the adjacent subchannel without interference. Thereby, the average speed in the common information transmission channel will be saved.

However, the disadvantage of the prototype method is that while maintaining the average transmission speed of information in the line, the transmission range is significantly reduced, because carrier frequency remains the same. With an increased signal to noise ratio (s / n), the communication channel will completely disappear.

The objective of the invention is to improve the quality of communication of a radio modem adaptive radio transmission lines of discrete information.

The technical result of the invention lies in the fact that the proposed method allows, by varying the transmission frequency depending on the conditions of communication in the channel, to provide the optimal speed and range of communication. Indeed, if you increase the frequency, you can increase the transmission speed, with decreasing frequency, the absorption in the propagation medium decreases and, accordingly, the signal transmission range increases.

To ensure the technical result indicated, new features have been introduced into the method for controlling the speed and range of transmission in the adaptive radio channel of a discrete information data stream radio modem, which consists in quickly changing the parameters of the transmitted information streams using a modulator / demodulator, namely:

- in the initial state, the parameters of the radio line are tuned to the minimum transmission speed and the lowest frequency of the operating range;

- when a communication occurs with a remote transceiver, a threshold signal / noise ratio is determined;

- depending on the s / n level, the radio line is transferred to a higher transmission rate or to a higher frequency of information transmission, changing the settings of the modulator / demodulator, while continuously exchanging the characteristics of information reception quality between correspondents.

The achievement of the technical result consists in the fact that in the proposed method during the communication session, it is possible to switch to a lower / higher carrier frequency, but the transmission speed in the channel will be less / more. At a lower carrier frequency, the transmission speed will be low, but the transmission range will be the maximum possible, because on a low carrier, the attenuation in the atmosphere is minimal, but at the same time it is difficult to develop a high velocity in the channel at a low s / n ratio. At the same time, at a large carrier frequency, the communication range will be less, but there is the possibility of a significant (several tens of times) increase in the transmission speed in the channel.

The invention is illustrated in FIG. 1, which shows a functional diagram of a radio modem of an adaptive radio transmission line of discrete information streams that implements the proposed method.

A device that implements the claimed method (Fig. 1) contains a microcontroller - 1, programmable logic integrated circuit (FPGA) 2, digital-to-analog converter (DAC) 3, radio-frequency (RF) modulator 4, RF radiation amplifier 5, transmit carrier frequency synthesizer 6, RF switch 7, RF receive amplifier 8, RF demodulator 9, analog-to-digital converter 10, receive carrier frequency synthesizer 11.

Microcontroller 1 sets the operation parameters of each element in the circuit, controls their operation parameters, receives and sends data to the RF path (blocks 4-11) directly and via FPGA 2, analyzes the operation of the communication channel and sets the parameters and logic of the operation of the entire device. The remaining elements of the system work in their highly specialized functions.

The implementation of the method, it is advisable to demonstrate the example of the modem (Fig. 1).

In the radiation mode, the data array enters the microcontroller 1, the microcontroller sets the carrier frequency in the synthesizer 6, and also transfers the data depending on its program to the FPGA 2, which converts the data and transfers to the DAC 3. Data from the DAC in analog form is fed to the RF- modulator 4, where the carrier frequency is modulated. Next, the modulated signal is amplified in the RF radiation amplifier 5 and through the RF switch 7 enters the antenna-feeder device (AFU).

In receive mode, the microcontroller 1 sets the carrier frequency to the synthesizer of the receive carrier frequency 11. The RF signal comes from the AFU through the RF switch 7, which protects the receive path from the power of the RF amplifier 5, to the RF receive amplifier 8. The RF demodulator 9 transfers the signal from the carrier frequency to the operating frequency region of the frequency range of the ADC 10. The ADC digitizes the signal, and digital data is transmitted to FPGA 2, which decodes the signal depending on the type of modulation. Digital data is supplied to microcontroller 1, which it transmits to the user.

In the absence of communication, the radio modems of each correspondent are tuned to a pre-programmed, low carrier frequency and low transmission rate. Only after successful mutual digital communication (with receipts) between the two correspondents and the establishment of a signal / noise ratio sufficient to increase the data transfer speed, the radio modems of the correspondents synchronously increase the carrier frequency and the data transfer speed. Starting parameters for establishing communication (carrier and transmission speed), as well as intermediate parameters (the number of permissible frequency ranges and permissible transmission speed), are set by the user depending on the operating conditions of the radio modems.

Information sources

1. Pat. RF №2255422. A radio channel device for transmitting and receiving digital information. IPC H04B 7/00. Claim 10/15/2003, publ. 06/27/2005.

2. Pat. RF №2446558. Method of differential pulse code modulation-demodulation of signals. IPC H03M 3/00. Claim 01/31/2011, publ. 03/27/2012.

3. Pat. RF №2142200. Frequency-adaptive radio link for transmitting media of non-high-speed streams of discrete information. IPC H04B 7/005, H04L 7/00. Claim 05/26/1998, publ. 11/27/1999.

Claims (1)

A method for controlling the speed and transmission distance in a radio modem of an adaptive radio line for transmitting discrete information streams, which consists in operatively changing the parameters of the transmitted information streams using a modulator / demodulator, characterized in that in the initial state, the parameters of the radio line are tuned to the minimum transmission speed and the lowest operating frequency, and when a connection with a remote transceiver occurs, a threshold signal / noise ratio is determined and the radio link is transferred to more high speed transfer or a higher frequency of information transfer, changing the settings of the modulator / demodulator, while continuously exchanging the characteristics of the quality of information reception between correspondents.

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