RU2688920C1 - Apparatus and method for radio communication based on simo-ofdm technology - Google Patents

Abstract

FIELD: radio equipment.SUBSTANCE: invention relates to the field of radio equipment. Technical result of invention is achieved due to availability of analogue antenna switch, at least one additional receiving unit and SIMO processing unit, which allows commutation or complete disconnection of arbitrary data streams coming from receiving units in case of failure or reception of interference signal by one of receiving antenna-feeder paths and / or one of these receiving units.EFFECT: apparatus and method of transmitting data over a radio channel based on SIMO-OFDM technology with high noise immunity and reliability.4 cl, 4 dwg

Description

The invention relates to the field of radio engineering, namely, to devices and data transmission methods (ADF) over the air using SIMO-OFDM technology (Single Input Multiple Output, Orthogonal Frequency-Division Multiplexing) and can be used in both mobile and stationary systems radio communications, working in the topology of both "point-to-point" and "point-to-multipoint".

The claimed data transmission apparatus is made on the basis of the orthogonal frequency multiplexing technology (Orthogonal Frequency-Division Multiplexing -ODM).

OFDM is a digital modulation scheme that uses a large number (from several tens to several thousand) of closely spaced orthogonal subcarriers. The most common method of generating an OFDM signal (in an ADF transmitter) is to form a quadrature OFDM signal using an inverse discrete Fourier transform (ODFT), in particular, using an inverse fast Fourier transform (IFFT). Each subcarrier of such a signal is modulated according to the usual modulation scheme (for example, binary or quadrature phase shift keying (BPSK and QPSK, respectively), or quadrature amplitude modulation (QAM)) at a low symbol rate, while maintaining the overall data rate, as in normal single carrier modulation schemes in the same bandwidth. When receiving the OFDM signal in the ADF receiver, reverse operations occur. Thus, the OFDM signal is the sum of the orthogonal subcarriers, each of which is independently modulated using one of the modulation types (BPSK, QPSK, QAM, etc.). The method of OFDM is widely known in the literature, for example "OFDM for Wireless Communications Systems", R.Prasad, ArtechHouse (2004), 294 p., And is applied in practice.

One of the most negative phenomena that arise in the process of transmitting information over the air is the reflections and fading of the signal. A radio signal during propagation from source to receiver can be reflected from various obstacles. Also, radio signals during transmission can be affected by various types of interference and distortion. In addition, during transmission, the radio signal undergoes attenuation. As a result, at the receiving side, the signal energy may be below the sensitivity threshold of the receiver, which will lead to an erroneous reception.

One of the possible ways to improve noise immunity and combat the problems identified above is the use of diversity reception technology for two or more antennas (antenna diversity). This method is a form of radio technology with multiple inputs and multiple outputs (Multiple Input Multiple Output - MIMO), often used in OFDM systems, and is called SIMO (Single Input Multiple Output). The essence of the SIMO-OFDM method, on the example of one main and one additional antenna, is illustrated in the right part of Fig. 1. The main antenna works for both receiving and transmitting information, and the additional antenna works only at receiving.

The closest to the claimed invention are the apparatus and method for transmitting data over the air based on SIMO-OFDM technology, described in application KR 20110083142 (A), which use diversity reception technology for two or more antenna-feeder paths (antennas). The data of the device and the method of its operation are selected as prototypes of the claimed invention.

The disadvantages of the diversity reception technology for two or more antenna-feeder paths (antennas), including the deficiencies of the apparatus and the method of its functioning of the prototypes, include the following factors:

- failure of the main antenna-feeder path leads to the inoperability of the entire apparatus, since it loses the ability to work in the mode of signal transmission;

- the reception of an interfering signal by one antenna-feeder path (from another radio or interference transmitter) impairs the noise immunity of the entire apparatus (this is true mainly when using sector antenna-feeder paths).

The technical result of the invention is the creation of the apparatus and method of data transmission over the radio channel based on SIMO-OFDM technology with improved noise immunity and reliability, due to the presence of an analog antenna switch, at least one additional receiving unit and SIMO processing unit, which allows switching or full shutdown of arbitrary data streams coming from receiving units, in case of malfunction or reception of a signal, interference by one of the receiving antenna-feeder paths and / or about One of these receiving blocks.

The technical result achieved by creating a radio communication apparatus based on SIMO-OFDM technology, configured to operate in transmitting and receiving modes, comprising a digital modem connected to a transceiver and at least two receivers connected to an analogue antenna switch connected with at least two antennas of antenna-feeder paths, with the transceiver comprising a transmitting unit and a receiving unit connected to an analogue antenna switch, the receiver contains A digital unit connected to an analog antenna switchboard, a digital modem contains an interface unit connected to a control unit connected to a digital OFDM modem connected to a DAC unit and an ADC unit, while the digital OFDM modem contains a coding and decoding unit connected to the control unit, with an OBPF (inverse fast Fourier transform-based) information processing unit and a SIMO processing unit, which is connected to processing units of the received information based on an FFT (fast FU transform) Rye), each of which is connected to the ADC unit, each of which is connected to the receiving unit, and the processing unit of the transmitted information based on the IFFT is connected to the DAC unit, which is connected to the transmitting unit, while

- antenna-feeder paths are configured to receive and transmit signals to the radio;

- analog antenna switch, made with the possibility of bidirectional switching signals from any of its inputs / outputs connected to the antenna-feeder paths, to any of its input / output connected to the transmitting and receiving units, while the digital modem is configured to control switching ;

- the interface unit is configured to exchange information with transmitted and received signals and control over an external Ethernet network at the hardware level;

- control unit, made with the possibility of dividing the total data flow into information and control signals, with the ability to configure the units of the radio communication apparatus on the basis of control signals, as well as the overall control of the radio communications apparatus;

- coding and decoding unit, made with the possibility of error-correcting coding of transmitted signals and noise-resistant decoding of received signals;

- the processing unit of the transmitted information based on OBPF made with the possibility of the formation of the transmitted OFDM signal using OBPF and transfer it to

- DAC unit, which is configured to convert a digital transmitted signal into an analog signal and transmit it to

- transmitting unit, which is designed to amplify and transfer the analog signal of the intermediate frequency to a higher radio frequency and transfer the analog signal to the analog antenna switch;

- the receiving unit is configured to receive an analog signal from an analog antenna switch and transmit it to

- A / D unit capable of converting an analogue received signal into a digital signal and transmitting it to

- the processing unit of the received information based on the FFT is configured to recover data from the digital OFDM signal using the FFT and transmit them to

- SIMO processing unit, made with the possibility of operational and software switching or completely disconnecting the signals, while forming a single signal and transmitting it to the coding and decoding unit.

In a preferred embodiment of the apparatus, the SIMO processing unit is configured to generate a single signal by the method of optimal weight addition.

The technical result is also achieved by creating a radio communication method based on SIMO-OFDM technology, in which

in the transfer mode, perform the following operations:

- using the interface unit, receive information and control signals from the Ethernet network, convert signals from the hardware level to digital and transmit to

- a control unit with which it divides the general data flow into information and control signals, configures the units of the radio communication apparatus on the basis of the control signals, performs overall control of the radio communication apparatus, and transfers information signals to

- coding and decoding unit, with the help of which they perform noise-resistant coding of transmitted signals and transmit them to

- the processing unit of the transmitted information on the basis of OBPF (inverse fast Fourier transform) by which form the transmitted OFDM signal using OBPF and transmit it to

- A DAC unit, with which a digital transmitted signal is converted into an analog signal and transmitted to

- the transmitting unit, by means of which the analog signal of the intermediate frequency is amplified and transferred to a higher radio frequency and the analog signal is transmitted to

- analog antenna switch, with which the signal is switched from one of the inputs to one of the outputs under the control of a digital modem and transmit the signal to

- antenna-feeder path through which the signal is transmitted to the radio broadcast;

in the reception mode, perform the following operations:

- using antenna-feeder paths, they receive signals from a radio broadcast and transmit to

- Analog antenna switch that switches signals from one of the inputs to one of the outputs under the control of a digital modem and transmits signals to

- the receiving units with the help of which amplify and transfer analog signals from a high radio frequency to an intermediate frequency and transmit analog signals to

- ADC blocks, with the help of which they convert analog received signals into digital signals and transmit them to

- processing units of the received information based on the FFT, with which they recover data from the digital OFDM signal using the FFT (fast Fourier transform), thus forming digital information signals and transmitting them to

- SIMO processing unit, with the help of which they carry out operational and software switching or a complete shutdown of signals, with the subsequent formation of a single signal and its transfer to

coding and decoding unit, with which they perform noise-resistant coding of the transmitted signal and transmit it to

- the control unit with which Ethernet signals are generated and transmitted to

- interface unit with the help of which Ethernet signals are converted from digital to hardware level and transmitted to the Ethernet network.

In a preferred embodiment of the method, using the SIMO processing unit, operational and programmatic switching or complete disconnection of the signals is performed, followed by the formation of a single signal by the method of optimal weight addition.

For a better understanding of the claimed invention, the following detailed description thereof is provided with corresponding graphic materials.

FIG. 1. Diagram of SIMO-OFDM diversity reception technology for two or more antennas (antenna diversity), made in accordance with the prototype and invention.

FIG. 2. The block diagram of the data transmission apparatus over the air based on the SIMO-OFDM technology, made in accordance with the invention.

FIG. 3. Scheme of operation of the analog path of the data transmission apparatus over the radio channel based on SIMO-OFDM technology in the normal mode, made in accordance with the invention.

FIG. 4. Scheme of operation of the analog path of the data transmission apparatus over the radio channel based on the SIMO-OFDM technology in the event of a malfunction or reception of the interference signal of one of the receiving antenna-feeder paths and / or one of the receiving blocks, made in accordance with the invention.

Items:

1 - analog antenna switch;

2 - digital modem;

3 - transceiver;

4 - receiver;

5 - transmitting unit;

6 - receiving unit;

7 - interface unit;

8 - control unit;

9 - digital OFDM modem;

10 - DAC unit;

11 - ADC block;

12 - processing unit of the transmitted information;

13 is a block for processing received information;

14 - SIMO processing unit;

15 - coding and decoding unit.

Let us consider in more detail the functioning in the normal mode of the claimed apparatus and method of data transmission over the radio channel based on the SIMO-OFDM technology (Fig. 2-4).

In the mode of information transfer, the claimed apparatus and method operate as follows.

Information signals and control signals via the Ethernet network are fed to the interface unit 7 of the digital modem 2. In it, the signals from the hardware level are converted to digital signals, which are fed to the input of the control unit 8. In the control unit 8, the data flow is divided into information signals and control signals. Based on the control signals, all units included in the SIMO-OFDM communication apparatus are configured. Information signals are transmitted to block 15 encoding and decoding, where the signals are subjected to error-correcting coding. In essence, coding is the addition to the source information of additional, verification, information. When transmitting signals from the source to the receiver, an error may occur (radio and / or intra-system interference). At the receiving side during decoding, this additional, verification information allows detecting the presence of errors and correcting errors if they occur. Next, the encoded signals are received in block 12 of the processing of the transmitted information of the digital OFDM modem 9, in which using the inverse fast Fourier transform produces an OFDM signal. From the processing unit 12 of the transmitted information, the signals go to the DAC unit 10, where they convert the digital transmitted signal into an analog signal and then bring it (signal amplification, filtering, etc.) to parameters that are optimal for the first transmitting unit 5 of the first transceiver 3 Next, the analog signal of the intermediate frequency is supplied to the first transmitting unit 5 of the first transceiver 3, where the transfer of the analog signal to a higher radio frequency and amplification is performed. From the first transmitter unit 5 of the first transceiver 3, the analog high-frequency signal is fed to the input / output U1 of the analog antenna switch 1, where they switch to one of the inputs / outputs X1 ... XN (in the normal mode at X1). Next, from the input / output X1 ... XN to which the switching took place, the analog high-frequency signal arrives at the Al, A2 ... AN antenna-feeder path corresponding to this input / output (in normal mode at X1 on A1), which radiates radio waves.

In the mode of receiving information, the claimed apparatus and method operate as follows.

The analog high-frequency signals received by the antenna-feeder paths A1, A2 ... AN are fed to the corresponding inputs / outputs X1 ... XN of the antenna switch 1, where switching is performed to the inputs / outputs U1 ... YN (in the normal mode X1 ... XN to U1 ... YN, respectively). From the inputs / outputs of U1 ... YN of the antenna switch 1, analog high-frequency signals arrive at the receiving units 6 of the transceiver 3 and receivers 4 (in the normal mode to the corresponding ones), where they amplify, filter and transfer the analog signal from the radio frequency to the intermediate frequency. After receiving blocks 6, the analog signals arrive at the corresponding blocks of the ADC 11, where they restore the analog signals of the intermediate frequency (amplify the signal, filter, etc.) i.e. lead them to parameters that are optimal for ADC and subsequent digital processing. Then convert the analog signals to digital. From the ADC blocks 11, digital signals are fed to the corresponding blocks 13 of processing the received information, the output of which, thanks to the fast Fourier transform, generates information digital signals. Next, the received digital signals arrive at the SIMO processing unit 14, where they perform operational and program switching or completely disable the signals received from the receiving units 6 with the subsequent SIMO processing. After the conversion of signals received from the receiving blocks of 6, a single signal is formed, for example, by the method of optimal weight addition, or by another method known from the prior art (for example, “MIMO Technology: Principles and Algorithms, Bakulin MG, Varukina L.A. ., Kreyndelin VB, M .: Hotline - Telecom, 2014 - 244 s). This signal after subsequent processing increases the reliability of the restoration of the original signals, thereby improving the noise immunity of this communication equipment (in normal mode, SIMO processing uses all from 1 to N received digital data streams). Next, the resulting information digital signal is passed to the block 15 encoding and decoding, where the signal is subjected to noise-resistant decoding. The additional verification information added during coding makes it possible to determine the presence of errors in the received signal and, if they occur, correct it. Next, the information digital signal enters the control unit 8, where they form Ethernet signals and then transmit them to the interface unit 7 of the digital modem 2. In the interface unit 7, the received Ethernet signals at the hardware level are transmitted to the Ethernet network.

To improve the noise immunity and survivability of the claimed radio communication apparatus, the following blocks are introduced: analog antenna switch 1, additional second and subsequent receiving blocks 6 included in the second and subsequent receivers 4, and SIMO processing block 14. FIG. 2 shows a diagram of the claimed radio communication apparatus with these additional units. In case of failure of one or even several elements of the receiving analog paths (the receiving analog path consists of one antenna-feeder path and one receiving unit 6) analog antenna switch 1 allows you to quickly and automatically switch in such a way as to ensure the operation of the stated radio communications apparatus. At the same time, at least one of the elements of the receiving analog paths must remain intact, i.e. in case of failure of the antenna-feeder path A1, for example, the following configuration of the receiving analog path is possible: antenna-feeder path A2 and the first receiving unit 6, which is part of the first transceiver 3, etc.

FIG. 3 shows the standard version of the switching. The use of additional second and subsequent receiving blocks 6 (included in the second and subsequent receivers 4) allows, after SIMO processing of data received from these blocks, to increase the noise immunity of communication equipment. For optimal use of additional second and subsequent receiving blocks 6, in the case when one or several antenna-feeder paths are not working and / or receive a signal of interference, it is possible to switch or completely disable arbitrary streams received from the first and subsequent receiving blocks in order not to reduce noise immunity of communication equipment. FIG. 4 depicts one of the switching options in case of failure and / or reception of the antenna-feeder path A1. In this case, the second receiver 4 is turned off and the data received by it is not used in SIMO processing, and the analog signal received by the antenna-feeder path A2 is switched to the first transceiver 3.

Although the above described embodiment of the invention has been set forth to illustrate the claimed invention, it will be clear to those skilled in the art that various modifications, additions and substitutions are possible without departing from the scope and meaning of the claimed invention disclosed in the attached claims.

Claims (19)

1. Radio communication apparatus based on SIMO-OFDM technology, configured to operate in transmitting and receiving modes, comprising a digital modem connected to a transceiver and at least two receivers connected to an analog antenna switch connected to at least two antennas antenna - feeder paths, the transceiver comprising a transmitting unit and a receiving unit connected to an analog antenna switch, the receiver comprising a receiving block connected to an analog antenna switch, the digital modem contains an interface unit connected by a control unit connected to a digital OFDM modem connected to a DAC unit and an ADC unit, while the digital OFDM modem contains a coding and decoding unit connected to the control unit to the processing unit of the transmitted information based on OBPF ( inverse fast Fourier transform) and a SIMO processing unit, which is connected to processing units of received information based on FFT (fast Fourier transform), each of which is connected to an ADC unit, each of which is union of a receiving unit and processing unit of the transmitted information based on the IFFT unit coupled to the DAC, which is connected to the transmitting unit, wherein - antenna-feeder paths are configured to receive and transmit signals to the radio; - Analog antenna switch is configured to perform bidirectional switching of signals from any of its inputs / outputs connected to antenna-feeder paths to any of its input / output connected to transmitting and receiving units, while the digital modem is capable of controlling switching; - the interface unit is configured to exchange information with transmitted and received signals and control over an external Ethernet network at the hardware level; - the control unit is made with the possibility of dividing the total data flow into information and control signals, with the possibility of configuring the units of the radio communication apparatus on the basis of control signals, as well as the general control of the radio communications apparatus; - the encoding and decoding unit is adapted to the error-correcting coding of the transmitted signals and the noise-resistant decoding of the received signals; - the processing unit of the transmitted information based on OBPF made with the possibility of the formation of the transmitted OFDM signal using OBPF and transfer it to - DAC unit, which is configured to convert a digital transmitted signal into an analog signal and transmit it to - transmitting unit, which is designed to amplify and transfer the analog signal of the intermediate frequency to a higher radio frequency and transfer the analog signal to the analog antenna switch; - the receiving unit is configured to receive an analog signal from an analog antenna switch and transmit it to - A / D unit capable of converting an analogue received signal into a digital signal and transmitting it to - a block of processing the received information based on the FFT, made with the ability to recover data from the digital OFDM signal using the FFT and transmit them to - SIMO processing unit, made with the possibility of operational and software switching or completely disconnecting the signals, while forming a single signal and transmitting it to the coding and decoding unit. 2. The apparatus according to p. 1, characterized in that the SIMO processing unit is configured to generate a single signal by the method of optimal weight addition. 3. A radio communication method based on SIMO-OFDM technology, in which in the transfer mode, perform the following operations: - using the interface unit, they receive information and control signals from the Ethernet network, convert signals from the hardware level to digital and transmit to the control unit, by means of which they divide the total data flow into information and control signals, configure the radio communication apparatus units based on control signals, carry out general control of the radiocommunication apparatus, and information signals are transmitted to the coding and decoding unit, with the help of which interference-resistant coding is performed signals and transmit them to the processing unit of the transmitted information based on OBPF (inverse fast Fourier transform), by which they form the transmitted OFDM signal using OBPF and transmit it to the DAC unit, by which they convert the digital transmitted signal into an analog signal and transmit it to transmitting unit, with which amplify and transfer the analog signal of the intermediate frequency to a higher radio frequency and transmit the analog signal to the analog antenna switch, with the help of which wiping a signal from one of the inputs to one of the outputs under control of the digital modem and transmitting the signal to the antenna feeder circuit with which the transmitted signal in airwaves; in the reception mode, perform the following operations: - using antenna-feeder paths, they receive signals from the radio and transmit to an analog antenna switchboard, by which they switch signals from one of the inputs to one of the outputs under control of a digital modem, and transmit signals to receiving units, by means of which they amplify and transfer analogue signals from high radio frequency to intermediate frequency and transmit analog signals to ADC blocks, with which they convert analog received signals to digital signals and transmit them to received and FFT-based information that is used to restore data from a digital OFDM signal using an FFT (Fast Fourier Transform), while generating digital information signals and transmitting them to a SIMO processing unit, through which they perform operational and programmatic switching or complete disconnection of signals, with the subsequent formation of a single signal and transmitting it to the coding and decoding unit, with which they perform noise-resistant coding of the transmitted signal and transmit it to the control unit, with the help of which Ethernet signals are formed and transmitted to the interface unit, through which Ethernet signals are converted from digital to hardware level and transmitted to the Ethernet network. 4. The method according to p. 3, characterized in that with the help of a SIMO processing unit, operational and programmatic switching or complete disconnection of the signals is performed, followed by the formation of a single signal by the method of optimal weight addition.

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