RU2293443C2 - Method and device for exchanging data between communication system with one carrying frequency and communication system with many carrying frequencies, transmitter for signals with one carrier and many carriers and receiver for signals with one carrier and many carriers - Google Patents

Abstract

FIELD: method and device for ex changing data between communication system with one carrying frequency and communication system with many carrying frequencies, and also transmitter and receiver for signals with one or more carrying frequencies.

SUBSTANCE: communication system with many carriers spectrally reads received signal from one carrier and depending on this takes decision about received data and/or imitates by its carriers the signal subject to transfer with one carrier.

EFFECT: efficiency of communications of communication systems with one and many carrying frequencies and structure of transmitter and receiver.

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Description

The invention relates to a method and apparatus for exchanging data between a communication system with one carrier (frequency) and a communication system with many carriers (frequencies), as well as to a transmitter and receiver for signals with one and many carriers (frequencies).

To transmit communication signals through frequency-selective channels of multipath propagation of radio waves, the signals to be transmitted are converted from their normal frequency position after the low-pass filter by modulation to higher frequency regions. The higher frequency that is used for transmission is referred to as the carrier frequency or carrier. If this carrier frequency is high enough, then the advantage of radio transmission can be successfully used.

Communication systems on a carrier (frequency), that is, devices for transmitting signals by means of a high-frequency communication technique, can use single or also many carriers (frequencies) for transmission. A system that uses only one carrier frequency or, accordingly, one carrier, is usually referred to as a system with a single carrier (frequency) (Single Carrier System). Systems that use many carrier frequencies for transmission are also known as multi-carrier systems (Multi Carrier Systems).

A typical representative of a multi-carrier communication system is an OFDM system. OFDM stands for Ortogonal Frequency Division Multiplexing, i.e., multiplex transmission with orthogonal frequency division multiplexing. This system is particularly well suited for highly distorted terrestrial digital signal transmission. For example, OFDM systems are used in digital broadcasting.

In addition, an OFDM-type system allows the use of Frequency Division Multiple Access (FDMA), that is, which can be successfully used primarily in the mobile radio technology. In the case of FDMA, the available bandwidth of the transmission channel is divided into a plurality of adjacent disjoint partial frequency channels. Separate partial frequency channels are then used as separate communication channels for various connections.

In contrast, in OFDM, communication connection information symbols are transmitted, so to speak, in parallel through a plurality of such partial frequency bands.

Transmission in one separate partial frequency band occurs narrowly. Therefore, a separate partial frequency band requires a relatively small bandwidth for transmission. Due to the small bandwidth of the partial frequency band as a whole, the frequency-selective transmission channel is divided into many non-frequency-selective AWGN (Additive White Gaussian Noise) partial transmission channels. This allows the receiving side to implement an effective frequency band corrector, which usually consists of a Fast Fourier Transformation (FFT) block and a channel estimation and correction block. Thus, mainly due to the parallel transmission of information symbols through a plurality of partial frequency bands, also in the case of multipath channels with strong distortion, despite this, a very high transmission quality is possible. In addition, by adding a time prefix to the OFDM component of the useful symbol, the intersymbol interference that occurs due to the generation of an echo in the transmission channel can be effectively reduced.

A disadvantage in the case of communication systems with many carrier frequencies known so far, however, is that communication with a communication system with a single carrier frequency is not provided and not possible without further additional, not insignificant costs. For example, a communication system with a single carrier frequency, in which the data to be transmitted is modulated to a single carrier frequency by means of Frequency Shift-Keying (FSK), that is, it cannot exchange data with an OFDM-type system.

An object of the present invention is therefore to provide a method and apparatus for exchanging data between a communication system with a single carrier frequency and a communication system with many carrier frequencies. In addition, the transmitter and receiver structures that are more economical in terms of cost should be indicated both for signals with one carrier frequency and with many carrier frequencies.

This problem is solved by a method for exchanging data between a communication system with a single carrier frequency and a communication system with many carrier frequencies with features according to claim 1, a corresponding device with features according to claim 10, as well as a transmitter and receiver for signals on a single carrier frequency and at many carrier frequencies with features according to paragraph 14 or, respectively, 15 of the claims. Preferred embodiments of the invention are the subject of the dependent claims.

It should be noted especially that this structure of the transmitter and receiver is not limited only to modulation of the FSK type of frequency manipulation, but can be applied to the class of digital nonlinear types of modulation and analog nonlinear and linear types of modulation in general. Classical analog nonlinear types of modulation include FM (frequency modulation) and AM (angular modulation), respectively, their digital derivatives: FSK frequency shift keying and continuous phase modulation with CPFSK (Continuous Phase Frequency-Shift-Keying), which is also called continuous phase shift keying). CPM modulation (Continious Phase Modulation). Although Gaussian Minimum Shift-Keying (GMSK) is linear modulation, it can be interpreted as a special case of FSK so that the above-mentioned transmitter and receiver structures can also be applied to GMSK modulated systems, such as for example, GSM digital mobile telephony and DECT, the European standard for digital wireless communications. The classic analog form of modulation is AM (amplitude modulation), which is still widespread in the medium and long wave broadcasting industry. The above transmitter and receiver structure can also be applied to AM.

An essential point of the invention lies in the fact that the exchange of data between a communication system with one carrier and with many carriers can be realized due to the fact that the communication system with many carriers simulates the spectral components of the signal of a communication system with one carrier. For this, a plurality of carrier frequencies of a communication system with many carrier frequencies are mainly used.

The invention thus relates to a method for exchanging data between a single-carrier communication system and a multi-carrier communication system. On the receiving side, a multi-carrier communication system spectrally reads the received signal from one carrier and, depending on this, decides on the received data. On the transmitting side, the single-carrier signal to be transmitted is simulated by a multi-carrier communication system. For a two-way operation mode, a multi-carrier communication system spectrally reads the received signal from one carrier and, depending on this, makes a decision about the received data; Further, a multi-carrier communication system simulates with its carriers a single-carrier signal to be transmitted. While in a multi-carrier communication system, the Inverse Fast Fourier Transformation (IFFT) and / or Fast Fourier Transformation (FFT) FFT algorithm serves as multi-carrier modulation and / or multi-carrier demodulation in a communication system single carrier inverse fast Fourier transform IFFT and / or fast Fourier transform FFT is used to simulate the spectral components of a useful signal with a single carrier. In principle, it is thus possible to exchange data between both communication systems.

Preferably, the average frequency, frequency drift, and other essential system parameters of a single carrier communication system are consistent with the carrier spacing, average frequency, and other significant system parameters of a multi-carrier communication system. These system parameters of a single-carrier communication system are denoted in the same way as the system-inherent parameters of a system.

The decision on the received data is preferably made using the amplitude and phase of a spectrally read single-carrier signal. Amplitudes, as well as phases, can be analyzed relatively easily. In addition, they represent reliable criteria for a reliable decision on the received data.

In a preferred field of application of the invention, signals are transmitted and / or received by multi-carrier communication systems by means of Orthogonal Frequency Division Multiplexing orthogonal frequency division multiplexing. As already mentioned, OFDM is mainly used in the transmission of signals through frequency-selective channels with multipath propagation. It can be used successfully for digital broadcasting, communication via a power supply network and similar transmission methods using OFDM, as well as in the technology of mobile radiotelephone communication.

Finally, in a preferred embodiment of the method, a single-carrier communication system modulates signals by means of FSK frequency shift keying. Frequency manipulation is preferably used in the mobile radiotelephone communication technology and in the field of wireless telephony. It is suitable primarily for transmitting signals over the air.

In addition, the invention relates to a device for exchanging data between a single-carrier communication system and a multi-carrier communication system. At the same time, an absolute value / phase distributor is provided on the transmission path, which assigns the signal to be transmitted in terms of absolute value and phase to the carrier frequencies of the signal with many carrier frequencies and / or on the reception path, an absolute value / phase interpreter that estimates the carriers of the received signal with many carriers in absolute value and phase, and a decision block that makes a decision on the received data.

Preferably, the transmitter comprises a multi-carrier and single-carrier data source. The signals from a single carrier data source are fed through a multiplexer to an Inverse Fast Fourier Transformation (IFFT) unit. While in a multi-carrier communication system, the IFFT algorithm and / or the FFT algorithm serves as multi-carrier modulations and / or multi-carrier demodulations, in a single-carrier communication system, IFFT and / or FFT algorithms are used to simulate the spectral components of a useful signal with single carrier. According to the invention, instead of IFFT and / or FFT, the Inverse Discrete Fourier Transformation (IDFT) and / or Discrete Fourier Transformation (DFT) can also be used.

The receiver preferably contains a fast Fourier transform FFT block that converts the received signals from time to frequency domain, a demultiplexer that multiplexes the receive signal converted by the fast Fourier transform FFT block to carrier frequencies, and a single-carrier and multi-carrier data receiver.

With the forms of execution explained above, the device can be successfully implemented, in particular, for two-way data exchange between a communication system on a single carrier and a communication system with many carriers.

The invention further comprises a transmitter for single-carrier and multi-carrier signals. The transmitter contains a single-carrier and multi-carrier signal source. The single-carrier signal generated by the single-carrier data source is assigned by the absolute value / phase distributor in absolute value and phase to the carrier frequencies of the signal that was generated by the multi-carrier data source. The multiplexer multiplexes the absolute value / phase assigned by the distributor signals and signals from the multi-carrier data source to the carriers of the multi-carrier signal to be transmitted. Finally, the signals multiplexed by the multiplexer are fed to the IFFT unit, which converts them from the frequency to the time domain.

In addition, the invention also relates to a receiver for signals with one single carrier and with many carrier frequencies, which, among other things, contains an FFT block. The latter converts the received signals from the time domain to the frequency domain. Additionally, the receiver includes a demultiplexer, which multiplexes the received signals converted by the FFT unit to the carrier frequencies of the signal with many carrier frequencies. After the demultiplexer, an absolute value / phase interpreter is connected, which analyzes the summed signals according to the absolute value and phase. Finally, after the absolute value / phase interpreter, a decision block is included that makes a decision on the received data. After the decision block, the data is then fed to a single-carrier data receiver. The output signals of the demultiplexer can also be fed to a multi-carrier data receiver.

In the following, the invention is explained in more detail with reference to the drawings. The drawings show:

Figure 1 is an example implementation of a device for exchanging data by means of multi-carrier signals to which both single-carrier and multi-carrier signals can be transmitted;

Figure 2 is an example embodiment of a device for exchanging data between a single-carrier communication system and a multi-carrier communication system, in which a single-carrier system is a transmitter and a multi-carrier system is a receiver; and

Figure 3 is an example embodiment of a device for exchanging data between a single-carrier communication system and a multi-carrier communication system, in which a single-carrier system is a receiver and a multi-carrier communication system is a transmitter.

The device shown in FIG. 1 contains a transmitter as an input signal with many carrier frequencies, an OFDM signal source and as a signal source with a single carrier frequency signal source FSK 10 or, respectively, 12. In the transmitter, signals in the frequency domain are mainly generated and processed in digital form. Before being transferred, they are converted to the time domain.

The signals formed by the OFDM 10 signal source are converted by means of a quadrature amplitude modulator QAM 13 connected to it and a series-parallel converter 14 into a parallel signal. More specifically, the data packets contained in the serial input signal of the transducer 14, for example bits or bytes, are distributed along parallel lines in order to be able to be transmitted in parallel on many carrier frequencies.

The parallel output signals of the converter 14 are fed to a multiplexer 18, which multiplexes them into the carrier frequencies of the signal to be transmitted with many carrier frequencies. After the multiplexer 18, the IFFT block 22 is connected, which converts the supplied signals from the frequency to the time domain. These converted signals are then transmitted through the transmitter 24.

The signals with a single carrier frequency generated by the FSK 12 data source are modulated by a frequency domain modulator 17, more specifically, an FSK modulator, to a single carrier frequency. The signal formed by the FSK 17 modulator is then fed to an absolute value / phase distributor 20, which assigns the summed signal in absolute value and phase to the individual carrier frequencies of the signal with many carrier frequencies. The signals conjugated in this way are led to a multiplexer 18, which multiplexes them on separate carriers.

The signals thus formed at the receiver are transmitted through transmission channel 26 and received by receiver 28 on the transmission path. The signals received by the receiver 28 are fed to the FFT unit 30, which converts them from the time domain to the frequency domain. Subsequent signal processing then occurs mainly in digital form in the frequency domain.

After the FFT unit 30, a demultiplexer 32 is connected, which demultiplexes the output signals formed by the FFT unit 30 to the individual carriers of the received multi-carrier signal.

The output signals of the demultiplexer 32 are fed, on the one hand, to the serial-parallel converter 38, which converts them into a serial data stream and, through the quadrature amplitude modulation modulator QAM and the decision block, transmits to the data receiver OFDM 42. On the other hand, the output signals of the demultiplexer 32 lead to the absolute value / phase interpreter 34, which analyzes the signals of the individual carriers in absolute value and phase and transmits the signals thus estimated to a frequency demodulator t he area and the decision block 37.

The frequency domain demodulator and decision block 37 decides on the data sequence received and transmits the data thus obtained to the data receiver FSK 40.

The device shown in FIG. 1 thus makes it possible that FSK-modulated signals with a single carrier are transmitted, in particular sent and received, via a multi-carrier communication system. Thus, the advantages of multi-carrier transmission, such as very low noise sensitivity, are also available for signals with a single carrier. Although the transmission in the device of FIG. 1 is shown in only one direction, in principle, two-way data exchange is equally possible.

The device shown in FIG. 2 is a system for two-way data exchange between a single-carrier communication system and a multi-carrier communication system. A single-carrier communication system is a transmitter in this device, and a multi-carrier communication system is a receiver. Since the device is otherwise the same as that shown in FIG. 1, with the difference that a time domain modulator 16 is used, reference is made here to the previous description of the operation of the individual components.

Finally, FIG. 3 shows a device that is also designed for one-way data exchange between a single-carrier communication system and a multi-carrier communication system. Here, a single-carrier communication system is a receiver and a multi-carrier communication system is a transmitter. To describe the operation of the individual components, a reference is again made to the explanations to FIG. 1.

Claims (13)

1. A method of exchanging data between a single-carrier communication system and a multi-carrier communication system, characterized in that the multi-carrier communication system demultiplexes a received signal from a single carrier to separate multi-carrier communication systems, spectrally reads and, depending on this, receives a decision on the received data, and / or a multi-carrier communication system imitates a single-carrier signal to be transmitted with its carriers and multiplexes onto separate multi-carrier communication systems or at the receiving In the case of a torone, a multi-carrier communication system spectrally reads the received signal from one carrier and, depending on this, decides on the received data, and on the transmitting side the signal from one carrier to be transmitted is simulated with a multi-carrier communication system, while for a two-way operation, the communication system with many carriers spectrally reads the received signal from one carrier and, depending on this, makes a decision on the received data; further, a multi-carrier communication system simulates a single-carrier signal to be transmitted by its carriers. 2. The method according to claim 1, characterized in that the system-immanent parameters of the communication system with one carrier agree with the spacing of the carrier frequencies, the average frequency and other system-immanent parameters of the communication system with many carriers. 3. The method according to claim 2, characterized in that the system-immanent parameters of a single-carrier communication system describe a non-linear type of modulation of the type of frequency manipulation FSK- and / or continuous phase modulation with frequency manipulation CPFSK / continuous phase modulation of CPM and / or frequency manipulation with a minimum frequency shift MSK and / or Gaussian frequency manipulation with a minimum frequency shift GMSK and / or frequency modulation and / or angular modulation. 4. The method according to claim 2, characterized in that the system-immanent parameters of a single-carrier communication system describe a linear type of modulation as amplitude modulation and / or amplitude-shift coding ASK / pulse amplitude modulation PAM. 5. The method according to claim 1 or 2, characterized in that the decision on the received data is made based on the amplitude and phase of the spectrally read signal with one carrier frequency. 6. The method according to claim 1, characterized in that the communication system with many carrier frequencies transmits and / or receives signals by means of orthogonal multiplex transmission with frequency division multiplexing OFDM channels. 7. The method according to claim 1, characterized in that the communication system with a single carrier frequency modulates the signals through frequency manipulation FSK. 8. The method according to claim 1, characterized in that the communication system with a single carrier frequency modulates the signals by continuous phase modulation with frequency shift keying CPFSK. 9. The method according to claim 1, characterized in that the communication system with a single carrier frequency modulates the signals by amplitude modulation. 10. The method according to any one of claim 1, characterized in that the communication system with a single carrier frequency modulates the signals through analog or frequency modulation or angular modulation. 11. A device for exchanging data between a single-carrier communication system and a multi-carrier communication system, characterized in that an absolute value / phase distributor is provided on the transmitter, which assigns the signal to be transmitted with one carrier in absolute value and phase to a multi-carrier signal carrier , and / or at the receiver an absolute value / phase interpreter that analyzes the carriers of the received signal with many carriers in absolute value and phase, and the frequency domain demodulator included after it and b ok estimates, which decides on the received data, and the transmitter contains a data source with one carrier and many carriers, the signals of which are fed through a multiplexer to the inverse fast Fourier transform unit IFFT, which converts the supplied signals from the frequency to the time domain, and the receiver contains a fast Fourier transform FFT, which converts the received signals from the time domain to the frequency domain, a demultiplexer that multiplexes the transformed by the fast conversion block Ф Rieux FFT input signal to the carrier and the one data receiver and a multi-carrier frequencies. 12. A transmitter for signals with one carrier and many carriers, which contains a data source with one carrier and many carriers, the absolute value / phase distributor, which assigns a signal with one carrier from a data source with one carrier in absolute value and phase carrier signal with many carriers, a multiplexer that multiplexes the signals assigned by the absolute value / phase distributor, and signals from a multi-carrier data source to the carriers of the multi-carrier signal to be transmitted, atnogo Fast Fourier Transform IFFT, which converts the signals fed from the multiplexer from the frequency to the time domain. 13. A receiver for signals of a single-carrier and multi-carrier communication system, which comprises a fast Fourier transform FFT unit that converts received signals from a time domain to a frequency domain, a demultiplexer that multiplexes a reception signal converted by a fast Fourier transform FFT to signal carriers with many carriers, the absolute value / phase interpreter, which analyzes the signals supplied from the demultiplexer in absolute value and phase, connected after the absolute interpreter magnitude / phase a frequency domain demodulator and a decision unit that makes a decision on the received data, and a data receiver with one and many carriers.

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