DE102011076143B4 - Device, communication system and method - Google Patents

Abstract

Apparatus (100) adapted to determine a signal property of a received signal and to output an alarm signal if the signal characteristic of the signal does not belong to a set of one or more allowable signal characteristics, the signal property being one or a combination of the following: Modulation type, symbol rate, cyclostationary pattern; the device having a database storing the set of permitted signal properties; and wherein the device is designed to be taught to an environment in which it is used in order to store in the database the signal properties which occur in the environment and which are not caused by interferers, but are desired.

Description

Technical area

Embodiments of the present invention provide devices, communication systems, and methods that can be used to secure the reliability and timing of communications, such as in industrial automation or medical technology.

Background of the invention

Radio-based communication is also increasingly used in industrial automation technology, enabling more cost-effective and flexible manufacturing processes and the implementation of new automation concepts. The requirements for radio-based communication, in particular reliability and time behavior (real-time capability), are significantly higher for this application than, for example, for the home and office sector. The same applies to the use of radio-based communication in medical technology.

The fact that all radio-based communication systems share and compete for the limited resource radio spectrum proves to be problematic in meeting this requirement. The competition is particularly large in the ISM bands (frequency ranges that can be used without being allocated by regulatory authorities in industry, science, medicine, domestic and similar fields). In addition, high-frequency and low-frequency disturbances occur through, for example, microwave systems or arc welding or through transformers or motors. It should be noted that the propagation of electromagnetic waves is not localized.

Through the so-called frequency management or coexistence management, which is defined by the VDI / VDE guideline 2185, the coexistence of radio applications can be established and guaranteed, which is the basic requirement for the fulfillment of the requirements. The problem with this is that frequency management can only guarantee coexistence between detected systems. Third-party systems (eg mobile phones with WLAN, Bluetooth, etc.) and interference can disrupt the radio-based communication and thus adversely affect their reliability and timing.

However, even changes in the environment can lead to a reduction in reliability and timing, for example, with the concomitant loss of line of sight (LOS) between two radio systems or destructive interference of the signal due to multipath propagation.

In "Verein Deutscher Ingenieure e. V., "Radio-based communication in automation technology: coexistence of wireless solutions," VDI / VDE 2185 Part 2, 2008 "is described that the specifications of the frequency management z. B. by "... an automatic system for permanent monitoring of the radio spectrum to be installed, which may already detect irregularities, even if they have no effect on the plant operation."

In existing automatic systems for permanent monitoring of the radio spectrum, the spectrum (power over frequency) in the 2.4 GHz ISM band is measured and compared with the typical environmental conditions (mask) determined in a learning phase. If the measured power density spectrum exceeds the reference value by an adjustable threshold value, the system triggers an alarm via one or more interfaces.

Since foreign systems or interferers can also occur with a power below the reference value and collisions of systems with equal cutoff frequencies can not be detected on the basis of the spectral analysis, this form of realization is limited in principle to ensure coexistence and thus the availability and the time response.

Another option will be in DE 10200705478 described. It is used on the example of Bluetooth systems used list of frequencies not to be used due to interference (blacklist). This information is used to detect sources of interference based on channel patterns, the course of the fault and the bandwidth of the fault.

The US Pat. No. 6,690,746 B1 shows a signal detector for communication signals, which has a signal classifier, which in turn has a plurality of modules, which can detect one or more different signal types.

The DE 10 2004 025 056 A1 shows method and apparatus for ensuring access protection in a shared medium network.

Summary of the invention

It is an object of the present invention to provide a concept which makes it possible to detect interference in communication systems early and thus the reliability and the To secure the time behavior of the communication or to minimize its downtime.

This object is achieved by a device according to claim 1, a communication system according to claim 13, a method according to claim 14 and a computer program according to claim 15.

Some embodiments provide a device configured to determine a signal characteristic of a received signal and to output an alarm signal if the signal characteristic of the signal does not belong to a set of one or more allowable signal characteristics, the signal characteristic being one or a combination of the following : Modulation type, symbol rate, cyclostationary pattern

It has been found that in order to ensure reliability of communication, spectrum analysis is typically insufficient to detect all possible interferences. In particular, in cases in which a performance of the interference is below a permissible limit, for example defined in a spectrum mask, this interference can not be detected by a pure spectrum analysis. Furthermore, it has been recognized that typically in communication systems, one or more types of modulation are used by the participants of the communication system.

It is an idea of embodiments that, instead of the energy detection or in addition to this, signals present in the communication system are analyzed with regard to their signal properties, such as modulation mode, symbol rate and / or cyclostationary pattern, in order to detect unauthorized signal properties and thus unauthorized signals, to trigger an alarm signal.

This analysis of the received signals with regard to the above-mentioned signal properties has the advantage over pure energy detection that interferences or interferers whose power is lower than those specified in a spectrum mask are also recognized.

Thus, interferers and third-party systems below the typical transmission power can be detected, for example, in response to the triggered alarm signal appropriate measures to resolve the problem of interferers and third-party systems.

In some embodiments, the device may be cycled to receive the received signal to determine the signal property of the received signal. For example, the device may determine a cyclic power density spectrum of the received signal (such cyclic power density spectra are typically different for different types of modulation and symbol rates) and determine therefrom the modulation type and / or the symbol rate of the received signal.

In other embodiments, the apparatus may include a database storing the set of allowable signal characteristics (such as an amount of allowed modulation types, an amount of allowed symbol rates, and / or an amount of allowable cyclostationary pattern). For example, all types of modulation, symbol rates, and / or cyclo-stationary patterns that typically occur in the communication system (other than unwanted noise and interference) may be stored in this database. For example, the device can be taught to an environment in which it is used in order to store in the database the signal properties which occur in the environment and which do not originate from interferers but are desired.

Embodiments thus enable the detection of interferers or foreign systems in a communication system whose power is below a limit power, for example as defined by a spectrum mask, based on the analysis of the signal characteristics of the signals transmitted by these third-party systems.

According to further embodiments, the device may be designed to determine both a modulation type and a symbol rate of the received signal as the signal property of the received signal. Thus, interferers that use the same modulation type as desired systems (eg, a modulation type from the set of allowed modulation types stored in the database) but may use a different symbol rate than the desired systems (which are not stored in the database as an allowable symbol rate is). Conversely, this applies even if a faulty system uses an admissible symbol rate but an impermissible modulation type.

Further embodiments provide a device adapted to demodulate a received signal to obtain an address of a sender of the received signal and to issue an alarm signal if the address of the sender does not belong to a set of one or more allowable addresses.

It has been found that with pure energy detection, noise is not from distinguish desired signals when these interfering signals have the same frequency range as the desired signals and, for example, even the same modulation as the desired signals.

It is a further central idea of embodiments that, by demodulating the received signals to obtain the address of the sender of the received signals, it is also possible to distinguish interference signals from desired signals, although the interference signals have the same frequency range and / or modulation type as the have desired signals. Thus, the various systems present in a communication system are typically known and their addresses can be stored in the device as the set of allowed addresses so that the device can trigger the alarm signal upon detection of a sender address unknown to it (not allowed).

According to further embodiments, the device may be configured to discard payload data of the demodulated received signal. For example, the device may only be designed to evaluate a so-called header of the received signal in order to obtain the address of the sender of the received signal, while the useful data for the device is irrelevant.

According to further embodiments, the signals received by the device may be addressed to a receiver in a communication system which is different from the device. In other words, the device may be configured to receive and analyze or demodulate signals, irrespective of whether the signals are addressed to the device or not. Devices according to embodiments can therefore be designed to "listen" to their environment continuously for signals to output an alarm signal, if an address of a sender of the received signal and / or a modulation type of the received signal does not correspond to a valid address and / or a permissible modulation ,

According to further embodiments, a device may be configured both to analyze a received signal in terms of its modulation type, to trigger an alarm signal if the modulation type does not belong to the set of permissible types of modulation, and to further demodulate the received signal to obtain an address of the received signal Receive signals and to trigger the alarm signal or another alarm signal, if the address of the received signal does not belong to the set of permissible addresses.

According to further embodiments, an apparatus may be configured to demodulate a received signal to obtain a packet error rate in the received signal and to output the alarm signal or another alarm signal if the packet error rate exceeds a predetermined threshold. This not only allows the recognition of interferers or third-party systems, but also a detection of a malfunction or failure of known radio systems.

Brief description of the figures

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Show it:

1 a block diagram of a device according to an embodiment of the present invention;

2 a schematic diagram of a device according to an embodiment of the present invention;

3 a flowchart of a method according to another embodiment of the present invention;

4 a flowchart of a method according to another embodiment of the present invention; and

5a - 5c Examples of cyclic spectra of signals for different types of modulation and signal rates.

Detailed description of embodiments

1 shows a block diagram of a device 10 according to an embodiment of the present invention. The device 10 is configured to receive a signal property of a received signal 11 to determine, and to an alarm signal 13 if the signal property of the signal 11 is not associated with a set of one or more allowable signal properties, the signal property being one or a combination of the following: modulation type, symbol rate, cyclostationary pattern

By determining the signal property of the signal as a modulation type, symbol rate, cyclostationary pattern or a combination of these, as mentioned above, with the device 10 , Interferers whose performance is less than that specified in a spectrum mask.

5a shows by way of example the cyclic spectrum (or cyclostationary patterns) of a signal (also referred to as spectral correlation density (SCD) or spectral coherence function (SCF)), as determined by the device 10 (for example, with a cyclostationary signal analysis) can be determined to the signal property of the received signal 11 to determine. This in 5a The cyclic spectrum shown applies to BPSK (binary phase shift keying) with a symbol rate of half the sampling rate (sampling rate).

5b shows by way of example the cyclic spectrum (or cyclostationary patterns) of a signal for BPSK with a symbol rate of one quarter of the sampling rate.

5c shows by way of example the cyclic spectrum (or cyclostationary patterns) of a signal for QPSK (quadrature phase shift keying) with a symbol rate of half of the sampling rate.

A section through the cyclic spectra at α = 0 corresponds to the power density spectrum of the signal. From the comparison of 5a - 5c It becomes clear that the cyclic spectra or cyclic patterns differ for different types of modulation as well as for different symbol rates.

2 shows a schematic diagram of a device 100 according to an embodiment of the present invention. The device 100 is a possible example of a concrete education in 1 shown device 10 ,

As from the in 2 shown schematic diagram, the device is 100 a multi-level system. So does the device 100 an antenna 101 , a preprocessing stage 103 , a processing stage 105 , an interferer and foreign system detection stage 107a (hereinafter also referred to as a disturbance detection stage for short), an error detection stage 107b and a suggestion level 108a and an alert level 108b ,

At the in 2 shown device 100 be with the antenna 101 receive electromagnetic waves. Through a subsequent preprocessing with the preprocessing stage 103 (For example, bandpass filtering, frequency conversion, etc.) can be ensured that only signals of the frequency band to be observed (such as the 2.4 GHz ISM band) are examined. The device 100 Therefore, it may be configured to receive a plurality of signals and to deal with the preprocessing stage 103 to filter out the signals which are not in a frequency range of the device to be observed 100 lie. Therefore, in the subsequent step of processing with the processing stage 105 only the signals are processed, which are within the specified frequency range.

For example, if radio communication in the 2.4 GHz range with the device 100 is monitored, the device can 100 Hide communications outside this frequency range as they will not interfere with the 2.4 GHz frequency domain communications.

By processing the received signals following the preprocessing, the signals for the detection stages 107a . 107b processed statistically and with regard to telecommunications.

This is indicated by the processing stage 105 one unity 109 for energy detection, one unit 111 for cyclostationary signal analysis of the received (and preprocessed) signals and a unit 113 for demodulating the received (and preprocessed) signals.

In other words, the statistical and telecommunications processing includes energy detection, cyclostationary signal analysis of the received (and preprocessed) signals and demodulation of the received (and preprocessed) signals.

At energy detection (performed by the unit 109 ) can measure the spectrum (power over frequency) of all existing signals in the environment of the antenna 101 the device 100 be determined. By the preprocessing of the received signals (by the preprocessing stage 103 ) and thus the limitation to a predetermined frequency range, the energy detection can be carried out only in a certain frequency range, which reduces the computational effort to determine the spectrum.

Through the cyclostationary signal analysis (performed by the unit 111 ), the types of modulation, signal rates and / or cyclo-stationary pattern of the received signals (in the predetermined frequency range) can be determined.

The cyclostationary signal analysis relies on the exploitation of periodicity exhibited by each modulated signal. Such signals are also called cyclostationary, ie their first order moments (mean m _x (t)) and second order (autocorrelation function R _XX (t ₁ , t ₂ )) have periodicity: m _x (t) = m _× (t + k × T), R _XX (t ₁ , t ₂ ) = R _XX (t ₁ + k × T, t ₂ + k × T).

For example, a signal may be evaluated for cyclostationarity by spectral correlation, also known as a cyclic periodogram. The modulation type can be determined with the CFD since differently modulated signals (BPSK, AM, FSK, MSK, QPSK, PAM) have almost identical power density spectra but significantly different cyclic power density spectra. Stationary noise, on the other hand, has no spectral correlation and can therefore be easily distinguished from signals.

In other words, the device can 100 be configured to determine a cyclic power density spectrum of a received signal to obtain the modulation type and / or the symbol rate of the received signal based on the cyclic power density spectrum (for example, obtained from a section through the cyclostationary pattern of the signal).

The demodulation of the received signals (performed by the unit 113 ) serves to provide the data contained in the signal to the detection stages 107a . 107b provide.

According to some embodiments, the device may 100 be designed to demodulate only received signals whose cyclo-stationary pattern, modulation type and / or symbol rate belongs to the set of associated cyclostationary patterns, modulation types and / or symbol rates.

The subsequent detection with the detectors 107a . 107b uses the data obtained during processing. The Störerdetektionstufe used for the detection of interferers and third-party systems and has the task to increase safety and reliability. For this purpose, it can use statistical and telecommunication-derived data (the spectrum, the modulation types and addresses) with values from a first database 115 to compare.

In this first database 115 All registered systems (for example, all desired transmitters in the environment of the device 100 ) with associated zyklostationärem pattern, associated modulation, symbol rate, frequency range, transmit power and / or address (for example, MAC address) be deposited.

The jammer detection stage 107a can be a unit 115 to compare the determined spectrum with patterns from the first database 115 exhibit. This will allow a third-party system by simply comparing the spectrum with those in the first database 115 stored pattern is compared.

Further, the jammer detection stage includes 107a one unity 117 for comparing the signal characteristics of the received signals (determined by the cyclo-stationary signal analysis) with the set of permitted signal characteristics from the first database 115 , Thus, foreign systems can still be detected by the modulation types obtained in the cyclostationary signal analysis.

If third-party systems use the same cyclostationary patterns, modulation types, and / or symbol rates as the (desired radio systems) used, they may possibly be from the two detectors or units 115 . 117 can not be detected This includes the fault detection stage 107a one unity 119 for comparison of the addresses obtained by the modulation of the sender of the received signals with allowable addresses (for example MAC addresses) from the first database 115 , The reading of the addresses from the demodulated data stream and the comparison with the (in the first database 115 stored) solves the problem of foreign systems with the same modulation types as the desired radio systems.

The jammer detection stage 107a therefore allows detection of extraneous systems, by a simple comparison of the spectrum, of a particular signal property (such as cyclostationary pattern, modulation type, symbol rate, or a combination thereof) as well as the addresses in the first database 115 stored specifications for the spectrum, the specific signal property and addresses.

The detectors 115 . 117 . 119 to detect interferers and third-party systems thus enhance both the security and reliability of a communication system by the device 100 is used.

According to further embodiments, the database 115 can also be divided, so for example, a separate database for the specifications for the spectrum, a separate database for the permissible signal properties and a separate database for the permissible addresses in the device 100 exist, each detector or unit 115 . 117 . 119 the jammer detection stage 107a is associated with the respective database associated with it.

As mentioned earlier, in a communication system, by the device 100 Wanted systems exist, the signal properties used for their signals and addresses in the first database 115 are stored, and the device 100 can do this be used to determine foreign systems, which are not desirable in the communication system.

This determination of the foreign systems may be the device 100 Among other things, by detecting the modulation of the signals emitted by these third-party systems as well as the recognition of the addresses of the sender of these signals. According to some embodiments, the device may 100 also be designed to compare only the addresses of the sender with the allowable addresses whose received signals have a permissible signal property (for example, a permissible modulation type, a permissible symbol rate, and / or a permissible cyclostationary pattern), it can be prevented, for example Alarm signal has already been triggered due to an illegal signal property and then another alarm signal or the same alarm signal is triggered again due to an invalid address of the sender of the received signal. According to further embodiments, the device 100 be designed to also perform the demodulation of received signals only if their particular signal property belongs to the set of permissible signal properties.

According to further embodiments, the amount of permissible signal characteristic may vary. For example, the device 100 be adapted to add new types of modulation, symbol rates and / or cyclostationary patterns to the set of allowed modulation types, symbol rates and / or cyclostationary patterns (for example, when a new desired system is added to the communication system) or modulation types, symbol rates and / or cyclo-stationary patterns from Remove amount of allowed modulation types, symbol rates, and / or cyclostationary pattern (for example, if one or more desired systems are removed from the communication system).

This also applies analogously to the quantity of permissible addresses, ie the device 100 may be configured to add new addresses to the set of allowed addresses (for example, when new desired systems are added to the communication systems) or to remove addresses from the set of allowed addresses (for example, when desired systems are removed from the communication system).

A number of the allowed modulation types, symbol rates, and / or cyclo-stationary patterns need not necessarily correlate with a number of allowed addresses, since several systems (with different addresses) can typically use the same modulation type, symbol rate, and / or the same cyclostationary pattern.

According to further embodiments, the device 100 be formed to discard payload data of a received signal, after demodulation, as this payload for the device 100 are typically not relevant or not for the device 100 are determined.

Furthermore, the device 100 the fault detection stage 107b on. The error detection stage 107b has a unit 121 for CRC check or CRC check (CRC-cyclic redundancy check, cyclic redundancy check). Furthermore, the fault detection stage 107b one unity 123 for determining the packet repetition rate.

These two units or detectors 121 . 123 serve to detect faulty-working or failed (desired) systems. For example, the unit 121 perform a checksum check on the demodulated data stream and compare the packet error rates gained thereby with a threshold. If this threshold is exceeded, so can by the alarm level 108b an alarm signal is output.

Furthermore, can be with the detector or the unit 123 by retrieving the packet number in the header of the data stream (a received signal) to register packet retries which, in the case of a very large number, indicate a failed or faulty system. If, for example, the packet repetition rate exceeds a certain threshold value, then the alarm level can 108b send an alarm signal.

The units 115 . 117 . 119 . 121 . 123 For example, they may perform their detection steps on the received signal in parallel. If a threshold value (for example in the spectrum, at the packet error rate or at the packet repetition rate) is exceeded or a modulation type or an address is not registered in one of these parallel detection steps, the device may 100 Alarm can sound, for example, from the alert level 108b the alarm signal is output. Such alerting may be audible or visual. In other words, the device can 100 be formed, the alarm signal issued visually or audibly.

According to further embodiments, the device 100 be configured to output the alarm signal in (electronic) message form, for example in the form of an e-mail or short message (so-called SMS).

In addition to alerting, the proposal level 108a Also, information about the nature of the error and steps to fix it to be provided. This data can be the suggestion level 108a for example, from a knowledge base, such as a second database 125 Respectively.

According to further embodiments, the alarm level 118b be formed depending on the error occurred (for example, depending on which of the units 115 . 117 . 119 . 121 . 123 an alarm signal is triggered) generate various alarm signals.

Furthermore, the proposal level 108a in addition to the output of the alarm signal, provide information for remedying the error causing the alarm signal (depending on which of the units 115 . 117 . 119 . 121 . 123 the alarm signal was triggered).

• • Störern und Fremdsystemen unterhalb der typischen Sendeleistung,
• • fehlerhaft konfigurierten Funksystemen (z. B. falsche MAC-Adresse),
• • fehlerhaften/ausgefallenen Funksystemen,
• • und destruktiven Veränderungen der Umgebung (Funkkanal) möglich.

In summary, the builds in 2 shown device 100 to possibly already known monitoring alarm systems, which perform only an energy detection. Suitable extensions (such as cyclo-steady state signal analysis and demodulation) eliminate the limitations described in the introductory part of this application. This is the detection of:

• • interferers and third-party systems below the typical transmission power,
• • faulty configured radio systems (eg wrong MAC address),
• • faulty / failed radio systems,
• • and destructive changes of the environment (radio channel) possible.

Furthermore, in addition to a mere alert, instructions are provided in accordance with the irregularity so that appropriate action can be taken without delay and also by non-specialized personnel. The localization of interferers and third-party systems also guarantees a quick location of these.

According to further embodiments, the device 100 also serve to allow a localization of interferers and third-party systems.

In a simple embodiment, for example, in that only disturbers with false modulation types are to be detected, in the device 100 , except for the unit 111 for cyclostationary signal analysis, the unit 117 for comparison with the permissible signal properties and the unit 108b for alarming, all other units are omitted (the permissible signal properties can be, for example, directly in the unit 117 get saved). Such a device may therefore be arranged to determine a signal characteristic of the received signal, for example to analyze the received signal to determine which modulation type, symbol rate and / or which cyclostate pattern it has and to output an alarm signal if the signal property of the signal not belong to a set of one or more allowable signal properties. Already in this simplest embodiment, a detection of interferers and foreign systems below the typical transmission power is achieved compared to the pure energy detection.

Furthermore, there may be applications in which only third-party systems or interferers are to be detected which emit signals whose signal properties may have the same signal properties as the signals of desired systems.

In another simple embodiment, except for the unit 113 for demodulation, unity 119 to compare the addresses as well as the unit 108b to send out the alarm signal, all other units are omitted (the allowed addresses can be in the unit 119 be saved). Such a device may therefore be arranged to demodulate a received signal to obtain an address of a sender of the received signal and to issue an alarm signal if the address of the sender does not belong to a set of one or more allowable addresses. In this further simple embodiment, a detection of foreign systems and interferers is thus possible, the transmission power is below a predetermined limit and whose modulation type corresponds to a permissible modulation.

Furthermore, in 2 schematically a transmitter 130 and a receiver 132 shown. The transmitter 130 For example, a signal can be sent to the receiver 132 send. This signal is further from the device 100 which, as explained above, may analyze the signal to output an alarm signal if the transmitter does not belong to a group of desired transmitters.

Embodiments of the present invention therefore provide a communication system having a device configured to determine a signal characteristic of a received signal and to output an alarm signal if the signal characteristic of the signal does not amount to one in a database 115 stored one or more permissible signal properties, the signal property being one or a combination of the following: modulation type, symbol rate, cyclostationary pattern. Furthermore, the device has the transmitter 130 on, the trained is to transmit a signal having a certain signal property, the particular signal property of the signal in the database 115 stored as a permissible signal property.

Another embodiment provides a communication system having means adapted to demodulate a received signal to obtain an address of the sender of the received signal and to issue an alarm signal if the sender's address does not reach a database stored in a database Quantity of one or more allowed addresses belongs. Furthermore, the system has the transmitter 130 configured to transmit a signal having an address of the transmitter, wherein the address of the transmitter is stored in the database.

These two systems can also be used in the 2 shown additional units of the device 100 be extended.

Commonly, these two systems have that transmitter 130 typically the data to the receiver 132 addressed and not to the device which analyzes or demodulates the received signal. The signal received by the device is therefore typically to the receiver 132 addressed, which is different to the device 100 (For example, in a separate housing of the device) is arranged. According to further embodiments, the transmitter 130 only the address of the recipient 132 but not recognize the address of the device for demodulating or analyzing the received signal. For example, the device needs 100 not necessarily have an address in the system.

According to further embodiments, the device may be configured to transmit no signals in the frequency range observed by it, but only to receive signals in this frequency range.

According to further embodiments, the described communication system systems may also comprise a plurality of transmitters, the modulation types and / or addresses used being stored in the database (s) of the devices used for comparison.

In summary, embodiments enable an automatically operating monitoring alarm system, which makes it possible to detect interferences by interference or foreign systems, changes in the radio channel and malfunction / failure of individual radio systems early and thus to ensure the reliability and timing of the radio-based communication or minimize their downtime.

Although in the foregoing the device 100 is used as an example to increase communication security in a radio-based communication system, systems and devices according to further embodiments can also be used in wired communication systems.

3 shows a flowchart of a method 200 according to an embodiment of the present invention.

The procedure 200 includes a step 201 determining a signal property of a received signal.

Furthermore, the method comprises 200 one step 203 outputting an alarm signal if the signal characteristic of the received signal does not belong to a group of one or more permissible signal properties.

The signal property that is determined is one or a combination of the following: modulation type, symbol rate, cyclostationary pattern. The procedure 200 For example, from the device 100 with the unit 111 to the cycle-stationary signal analysis, the unit 117 for comparing the signal property of the received signal with the allowable signal characteristics and the unit 108b be executed to generate the alarm signal.

Further shows 4 a flowchart of a method 300 according to a further embodiment.

The procedure 300 includes a step 301 demodulating a received signal to obtain an address of the sender of the received signal.

Furthermore, the method comprises 300 one step 303 issuing an alarm signal if the address of the sender of the received signal does not belong to a set of one or more permissible types of modulation.

The procedure 300 For example, from the device 100 with the unit 113 for demodulation, of unity 119 to compare the addresses and the unit 108b be executed to generate the alarm signal.

Although some aspects have been described in the context of a device, it will be understood that these aspects also constitute a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device.

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware or in software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM or FLASH memory, a hard disk, or other magnetic disk Electronic or optical memory are stored on the electronically readable control signals that can cooperate with a programmable computer system or cooperate such that the respective method is performed. Therefore, the digital storage medium can be computer readable. Thus, some embodiments according to the invention include a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is performed.

In general, embodiments of the present invention may be implemented as a computer program product having a program code, wherein the program code is operable to perform one of the methods when the computer program product runs on a computer. The program code can also be stored, for example, on a machine-readable carrier.

Other embodiments include the computer program for performing any of the methods described herein, wherein the computer program is stored on a machine-readable medium.

In other words, an embodiment of the method according to the invention is thus a computer program which has a program code for performing one of the methods described herein when the computer program runs on a computer. A further embodiment of the inventive method is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program is recorded for carrying out one of the methods described herein.

A further embodiment of the method according to the invention is thus a data stream or a sequence of signals, which represent the computer program for performing one of the methods described herein. The data stream or the sequence of signals may be configured, for example, to be transferred via a data communication connection, for example via the Internet.

Another embodiment includes a processing device, such as a computer or a programmable logic device, that is configured or adapted to perform one of the methods described herein.

Another embodiment includes a computer on which the computer program is installed to perform one of the methods described herein.

In some embodiments, a programmable logic device (eg, a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be a universal hardware such as a computer processor (CPU) or hardware specific to the process, such as an ASIC.

The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that modifications and variations of the arrangements and details described herein will be apparent to others of ordinary skill in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims (15)

Contraption ( 100 ) configured to determine a signal property of a received signal and to output an alarm signal if the signal characteristic of the signal does not belong to a set of one or more allowable signal characteristics, the signal property being one or more of a combination of the following is: modulation type, symbol rate, cyclostationary pattern; the device having a database storing the set of permitted signal properties; and wherein the device is designed to be taught to an environment in which it is used in order to store in the database the signal properties which occur in the environment and which are not caused by interferers, but are desired. Contraption ( 100 ) according to claim 1, which is adapted to subject the received signal to a cyclostationary signal analysis in order to obtain the signal characteristic of the received signal as a result of the cyclostationary signal analysis. Contraption ( 100 ) according to one of claims 1 or 2, configured to determine a cyclic power density spectrum of the received signal to obtain, based on the cyclic power density spectrum, the modulation type or the symbol rate of the received signal. Contraption ( 100 ) according to one of claims 1 to 3, which is arranged to analyze the received signal to determine which type of modulation it has and to output the alarm signal if the modulation type of the signal does not belong to a set of one or more permissible types of modulation. Contraption ( 100 ) according to one of claims 1 to 4, further adapted to demodulate the received signal to obtain an address of a sender of the received signal, and to output the alarm signal or another alarm signal if the address of the sender of the signal is not belongs to a set of one or more allowed addresses. Contraption ( 100 ) according to one of claims 1 to 4, which is adapted to demodulate the received signal only if the signal characteristic of the received signal belongs to the set of permissible signal characteristics, to obtain an address of a sender of the received signal, and to the alarm signal or to issue another alarm signal if the address of the sender of the signal does not belong to a set of one or more allowable addresses. Contraption ( 100 ) according to one of claims 1 to 6, which is adapted to receive a plurality of signals and to subject these plurality of signals to preprocessing, such as that of the device ( 100 ) the signal property is determined only by signals from the plurality of signals that are within a predetermined frequency range or such that the device ( 100 ) only the signals from the plurality of signals lying within a predetermined frequency range are demodulated. Contraption ( 100 ) according to one of claims 1 to 7, which is designed to output the alarm signal visually or acoustically. Contraption ( 100 ) according to one of claims 1 to 8, which is arranged to provide, in addition to the output of the alarm signal, information of the alarm signal triggering error. Contraption ( 100 ) according to one of claims 1 to 9, arranged to demodulate the received signal to obtain a packet error rate in the received signal and to output the alarm signal or another alarm signal if the packet error rate exceeds a predetermined threshold. Contraption ( 100 ) according to one of claims 1 to 10, which is designed to demodulate the received signal and to discard user data of the received signal. Contraption ( 100 ) according to one of claims 1 to 11, which is designed to determine a signal spectrum and to output the alarm signal or a further alarm signal if at least a portion of the determined signal spectrum exceeds a predetermined limit value for this component. Communication system comprising: a device ( 100 ) configured to determine a signal characteristic of a received signal and to output an alarm signal if the signal property of the signal does not amount to one in a database ( 115 The signal property is one or a combination of the following: modulation type, symbol rate, cyclostationary pattern, the device being designed to be taught to an environment in which it is used the signal characteristics occurring in the environment, which do not emanate from interferers, but are desired to store in the database; and a transmitter ( 130 ) configured to transmit a signal having a particular signal property; and wherein the particular signal property of the signal in the database ( 115 ) is stored as a permissible signal property. Procedure ( 200 ) with the following steps: determining ( 201 ) a signal property of a received signal; and Output ( 203 ) an alarm signal if the signal property of the received signal does not belong to a set of one or more allowable signal characteristics; wherein the signal property is one or a combination of the following: modulation type, symbol rate, cyclostationary pattern; and wherein the set of permitted signal properties are stored in a database; the method further comprising a step of learning to store in the database the signal characteristics which occur in an environment in which the method is used which are not emanating from interferers but are desired to be stored in the database. A computer program for performing one of the methods of claim 14 when the computer program is run on a processor.

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