Processing of frequency-modulated radio signals

Abstract

Examples include a method for processing frequency-modulated, multiplexed radio signals received from a first antenna and a second antenna, a radio receiver for carrying out the method for processing signals, a radio device comprising the radio receiver, and a motor vehicle comprising a radio receiver or a radio device.

Description

Technical field

[0001] The present disclosure relates to the field of receiving frequency-modulated radio signals. State of the art

[0002] In radiophony, a channel refers to a frequency range of electromagnetic radio frequencies assigned to a broadcasting station for transmitting audio content within a geographical area. In certain cases, the same channel may be assigned to two different broadcasting stations in two adjacent geographical areas, meaning that a radio receiver installed in a vehicle traveling in the border region between these two areas may receive frequency-modulated broadcast signals from different stations on the same channel. This manifests acoustically as an audio signal that can alternate between the stations transmitting on the same channel, thus affecting the listener's experience. These well-known situations are referred to as "co-channel interference."

[0003] Methods exist that can aid in the detection of co-channel interference (see, e.g., US 2020 / 007248 A1, US 2010 / 151809 A1, US 2016 / 211995 A1). These methods determine the probability of co-channel interference depending on various parameters. However, they are probabilistic methods and do not allow for a definitive determination of whether co-channel interference is actually present. Furthermore, no solution is known to reduce or eliminate co-channel interference once it is detected.

[0004] The present revelation aims to improve this situation. Summary

[0005] In this regard, a method for processing frequency-modulated, multiplexed broadcast signals received from a first antenna and a second antenna is proposed, the method comprising the following: - the selection in a multiplexed broadcast signal received by the first antenna of a first frequency band of the broadcast signal belonging to a particular channel; - the selection in a multiplexed broadcast signal received by the second antenna of a second frequency band of the broadcast signal belonging to the specific channel; - decoding a first broadcast station identifier of the specific channel from the broadcast signal contained in the selected first frequency band; - decoding a second broadcast station identifier of the specific channel from the broadcast signal contained in the selected second frequency band; - comparing the first and second radio station identifiers; and - detecting a co-channel interference situation by comparison.

[0006] Optionally, the method also includes a reduction of a quality coefficient previously stored in a memory of a radio receiver, wherein said quality coefficient is associated with a broadcasting station assigned to the specific channel as soon as a co-channel interference situation is detected.

[0007] Optionally, the procedure also includes the output of an audio signal derived exclusively from the broadcast signal received by the first or second antenna as soon as a co-channel interference situation is detected.

[0008] Optionally, the procedure also includes the deactivation of a so-called phase diversity method, which combines the broadcast signals received by the two antennas to improve the audio signal to be output as soon as a co-channel interference situation is detected.

[0009] Optionally, the procedure is carried out as soon as the probability of co-channel interference, determined by a probabilistic method, exceeds a predefined threshold.

[0010] Optionally, the first broadcast station identifier is decoded from a recombination of the broadcast signal contained in the selected first frequency band and the broadcast signal contained in the selected second frequency band; and the second broadcast station identifier is decoded exclusively from the broadcast signal contained in the selected first or second frequency band.

[0011] The application further relates to a radio receiver comprising at least one first tuner and one second tuner, at least one first and one second decoder, a computer and a memory; wherein the first and second tuner, the first and second decoder, the computer and the memory are configured to perform one of the methods described in the present disclosure.

[0012] Optionally, the first tuner is configured to select the first frequency band; the second tuner is configured to select the second frequency band; the first decoder is configured to decode the first broadcast station identifier of the specific channel from the broadcast signal contained in the selected first frequency band; the second decoder is configured to decode the second broadcast station identifier of the specific channel from the broadcast signal contained in the selected second frequency band; and the computer is configured to compare the first and second broadcast station identifiers and detect a co-channel interference situation based on this comparison.

[0013] The application further relates to a radio device comprising a radio receiver according to one of the embodiments described in the present disclosure.

[0014] The application further relates to a motor vehicle which has a radio or radio receiver according to one of the embodiments shown in the present disclosure.

[0015] The application further relates to a computer program product with instructions for carrying out one of the methods described in the present disclosure when this program is executed by a processor.

[0016] Finally, the application relates to a non-volatile, computer-readable storage device on which a program for carrying out one of the methods described in the present disclosure is stored when that program is executed by a processor.

[0017] The method according to the present disclosure thus makes it possible to reliably detect co-channel interference situations by cleverly comparing the broadcast station identifiers decoded from the broadcast signals of two different antennas. Certain embodiments of the method also make it possible to reduce or even eliminate the disturbances caused by co-channel interference by considering only the broadcast signal of one of the two antennas, for example by disabling the implementation of a so-called phase diversity method. Brief description of the drawings

[0018] Further features, details and advantages will become apparent from the detailed description below and from the analysis of the accompanying drawings, which show: Fig. Figure 1 schematically shows an example of a radio receiver. Fig. Figure 2 schematically shows an example of a radio device. Fig. Figure 3 schematically shows an example of a vehicle with a radio. Fig. Figure 4 shows an example of a method for processing multiplexed, frequency-modulated broadcast signals. Description of the embodiments

[0019] The following refers to Fig. 1 An example of a radio receiver 1 according to the present disclosure is described. A radio receiver in the present disclosure is to be understood as a device that processes broadcast signals from radio stations, in particular to extract audio content from them that can be reproduced for a listener.

[0020] The radio receiver 1 comprises a computer 11 and a memory 12. The memory 12 can store the program instructions executed by the computer 11. The computer 11 can be, for example, a processor, microprocessor, microcontroller, FPGA, etc. The memory 12 can, for example, comprise a ROM (Read-Only Memory), a RAM (Random Access Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), or other suitable storage means. The memory can, for example, comprise optical, electronic, or magnetic storage means. The computer 11 and the memory 12 are configured to perform one of the processing methods described in the present disclosure, in particular the one relating to Fig. Perform the 4 illustrated example procedures.

[0021] The radio receiver 1 further comprises at least one first tuner 13 and one second tuner 14. A tuner is a device that makes it possible to select a specific frequency band within a broadcast signal. This frequency band can then be processed, for example, to extract an audio signal from it. The first tuner 13 is configured to select frequency bands from broadcast signals received by a first antenna 33. The second tuner 14 is configured to select frequency bands from broadcast signals received by a second antenna 34. The first antenna 33 and the second antenna 34 are separate.

[0022] The radio receiver 1 further comprises at least a first decoder 15 and a second decoder 16. A decoder is a device that enables the decoding of signals contained in a radio signal after demodulation. The decoders 15 and 16 can, in particular, form parts of the computer 11 or, for example, correspond to computers that differ from computer 11.

[0023] In examples, the radio receiver 1 can in particular form part of a radio device 2, as in Fig. Figure 2 shows that the radio 2 may also include, for example, loudspeakers 21 configured to play back an audio signal extracted from a broadcast signal. The radio 2 may also include a screen 22 for displaying information to the listener.

[0024] In examples, especially in the ones in Fig. In Figure 3, the first antenna 33 and the second antenna 34 are arranged on a motor vehicle 3. In these examples, the motor vehicle 3 can include a radio 2 containing a radio receiver 1. In these examples, the radio 1 thus corresponds to a car radio, that is, a radio intended to be integrated into a motor vehicle such as a car, truck, or motorcycle. In these examples, the motor vehicle 3 can include a radio receiver 1.

[0025] In relation to Fig. In section 4, an example method 100 for processing frequency-modulated, multiplexed broadcast signals received by the first antenna 33 and the second antenna 34 is described below. The method 100 can be carried out, for example, by the radio receiver 1, in particular using its computer 11, its memory 12, and the first 13 and second 14 tuners.

[0026] It should be noted that Fig. 4 is merely a representation of the example procedure 100, which uses blocks to show the various operations that may be included in the procedure and are described later in the disclosure. In this context, this representation does not represent a sequence of operations. In other words, the operations relating to Fig. The operations described in section 4 are not necessarily performed sequentially and, in particular, can be carried out in a different order than the one described in the text. Fig. The four operations shown can be performed or performed in parallel. Likewise, it is not necessary for each operation to be performed once before the same operation is repeated a second time. An operation can be performed multiple times before another operation is performed. The frequency with which each operation is performed is independent and does not necessarily have to be linked to the performance of other operations.

[0027] A frequency-modulated broadcast signal is a familiar concept to those skilled in the field. This broadcast signal is also known as an FM radio signal, where FM is the acronym for "Frequency Modulation." In this case, the frequency-modulated broadcast signal is multiplexed because, in addition to the audio signal to be reproduced for the listener, it contains, in particular, digital information, including a broadcast station identification. The broadcast station identification of a broadcast signal allows the identification of the broadcasting station that transmitted the signal. In these examples, the broadcast station identification is transmitted according to the so-called "RDS" protocol ("Radio Data System"). This protocol is familiar to those skilled in the field and is defined, in particular, in the IEC 62106 standard. In these examples, the station identification is transmitted according to the RDS protocol via the PI code ("Program Identification").

[0028] As in Fig. As shown in Figure 2, the procedure 100 comprises an operation 110 in which a first frequency band of the broadcast signal, belonging to a specific channel, is selected from a multiplexed broadcast signal received by the first antenna 33. As stated above, a channel denotes a frequency range assigned to a broadcast station for transmitting audio content. The first frequency band of the broadcast signal is selected to identify a broadcast station from the broadcast signal received by the first antenna. For example, the first frequency band corresponds to or is contained within the entire frequency range of the specific channel under consideration. The selection 110 of the first frequency band can, for example, be performed by the first tuner 13.

[0029] As in Fig. As shown in Figure 2, the procedure 100 comprises an operation 120 in which a second frequency band of the broadcast signal, belonging to the same specific channel, is selected from a multiplexed broadcast signal received by the second antenna 34. The second frequency band of the broadcast signal is selected to enable the determination of a broadcast station identifier from the broadcast signal received by the second antenna. For example, the second frequency band corresponds to or is included within the entire frequency range of the specific channel under consideration. The selection 120 of the second frequency band can, for example, be performed by the second tuner 14.

[0030] These two operations involve using two tuners, each connected to a corresponding antenna, to process a broadcast signal transmitted on the same channel but received differently due to the respective sensitivities and orientations of the two antennas. The first and second frequency bands must each allow for the determination of a broadcast station identifier from the broadcast signals received by the first and second antennas, respectively. In some examples, the first and second frequency bands may be identical.

[0031] As in Fig. As shown in Figure 2, the procedure 100 comprises an operation 130 for decoding a first broadcast station identifier of the specific channel from the broadcast signal contained in the selected first frequency band. This operation is used to determine which broadcast station is transmitting the broadcast signal received by the first antenna. The decoding 130 of the first broadcast station identifier of the specific channel can, for example, be performed by the first decoder 15.

[0032] As in Fig. As shown in Figure 2, the procedure 100 comprises an operation 140 for decoding a second broadcast station identifier of the specific channel from the broadcast signal contained in the selected second frequency band. This operation is used to determine which broadcast station is transmitting the broadcast signal received by the second antenna. The decoding 140 of the first broadcast station identifier of the specific channel can, for example, be performed by the second decoder 16.

[0033] As in Fig. As shown in Figure 2, the procedure 100 includes an operation 150 for comparing the first and second broadcast station identifiers.

[0034] As in Fig. As shown in Figure 2, the procedure 100 includes an operation 160 for detecting a co-channel interference situation by comparison.

[0035] In some examples, a co-channel interference situation is detected when the first and second broadcast station identifiers are assigned to different broadcast stations.

[0036] Method 100, as disclosed herein, thus cleverly uses the signals received by two antennas to compare whether the broadcast signal received on the same channel by both antennas is actually transmitted by the same broadcasting station. If this is not the case, the method makes it possible to determine with certainty that the radio receiver is in a co-channel interference situation, since a first antenna receives a broadcast signal from a first station and a second antenna receives a broadcast signal from a second station.

[0037] Additional operations can optionally be included in Process 100 and are explained below. These operations can be integrated into Process 100 in any combination, unless explicitly stated otherwise.

[0038] In some examples, the procedure can be 100, as in Fig. Figure 2 shows that the operation also includes an operation 170 for reducing a quality coefficient associated with a broadcasting station connected to a specific channel, wherein said quality coefficient was previously stored in the memory of radio receiver 1 when a co-channel interference situation is detected. This allows the audio signal of the broadcasting station, which is reproduced for the listener, to be improved. The reason for this is that the radio receivers are configured to reproduce audio data corresponding to the broadcasting station selected by the listener. The radio receivers are thus configured to select the channel that transmits the broadcasting station selected by the listener with the best audio quality, taking into account quality coefficients previously stored in the memory of radio receiver 1, each associated with the various available channels of that broadcasting station.Consequently, by reducing the quality coefficient associated with the broadcasting station for the specific channel where a co-channel interference situation has been detected, the radio receiver may, if necessary, use another available channel of the broadcasting station chosen by the listener, especially if the quality coefficient of that channel is higher than that of the specific channel.

[0039] In some examples, Procedure 100 includes Operation 180 for reproducing an audio signal derived solely from the broadcast signal received by the first or second antenna. This Operation 180 is performed when a co-channel interference situation is detected. The purpose is to select only the broadcast signal received by one antenna to generate the audio signal to be reproduced for the listener. In this way, the broadcast signal received by the other antenna, which in the case of a co-channel interference situation corresponds to another broadcast station, will not interfere with the audio signal reproduced for the listener.Furthermore, this also makes it possible to use the tuner connected to the antenna, which is not used for playing back the audio signal, for another task, such as searching for another channel that is more advantageous than the specific channel where a co-channel interference situation was detected.

[0040] In some examples, and as in Fig.As shown, procedure 100 can further include operation 190 for deactivating a so-called "phase diversity method" as soon as a co-channel interference situation is detected. In this method, the broadcast signals received by the two antennas are recombined to create a recombined broadcast signal. The audio signal to be reproduced for the listener is then extracted from this recombined broadcast signal, thereby improving the quality of the audio signal compared to an audio signal extracted from a non-recombined broadcast signal. This is a well-known method, commonly referred to by the English term "phase diversity."These examples thus make it possible to avoid recombining samples extracted from the broadcast signal received by the first antenna, corresponding to a first broadcast station, with samples extracted from the broadcast signal received by the second antenna, corresponding to a second broadcast station. The aim of these examples is therefore to avoid impairing the audio signal to be reproduced for the listener.

[0041] In some examples, Method 100 is executed as soon as the probability of co-channel interference, determined by a probabilistic method, exceeds a predefined threshold. Examples of such probabilistic methods are described in particular in patent documents FR 3064853 and US 8064857. These examples make it possible to restrict the application of Method 100 to situations in which the probability of being in a co-channel interference situation is greater than a predetermined threshold. This makes it possible, in particular, to limit the time during which the radio receiver 1 uses two decoders to decode the broadcast signals received from the respective antennas, whereas only a single decoder is required when the signal to be decoded originates from a recombined broadcast signal.These examples thus make it possible to conserve the resources of radio receiver 1, especially those of computer 11, if the decoders are integral components of this computer 11, and to reduce its electrical energy consumption.

[0042] In some examples, the decoding of the first and second radio station identifiers is done as follows: - the first broadcast station identifier is decoded from a recombination of the broadcast signal contained in the selected first frequency band and the broadcast signal contained in the selected second frequency band; and - The second broadcast station identifier is decoded from the broadcast signal that is contained exclusively in one of the selected first or second frequency bands.

[0043] These examples make it possible to: a) to avoid the use of three decoders of radio receiver 1 for decoding the broadcast signals during the execution of procedure 100, or b) that during the execution of procedure 100 only two decoders of radio receiver 1 are used for decoding, which would reduce the quality of the audio signal output to the listener.

[0044] In the present case a), procedure 100 can be carried out by decoding the broadcast signals received by the first 33 and the second 34 antennas, as well as the broadcast signal reconstructed from the signals of each antenna. In this case, the two broadcast station identifiers are each extracted directly from the broadcast signals received by the antennas via a respective decoder, and the audio signal to be output to the listener is extracted from the recombined signal via a third decoder. Thus, the audio signal output to the listener during the execution of procedure 100 is a high-quality audio signal, since it always originates from the recombination of the broadcast signals received by both antennas.However, it is not necessary to use three decoders during the execution of Procedure 100 to maintain the transmission of the audio signal derived from the recombined broadcast signal and to determine whether radio receiver 1 is experiencing co-channel interference. In fact, it is possible to directly use the broadcast station identifier decoded from the recombined broadcast signal to compare it with the identifier decoded from one of the broadcast signals received by the antennas in order to detect co-channel interference. Therefore, only two decoders are required to perform Procedure 100, while maintaining the quality of the audio signal derived from the recombined broadcast signal throughout the procedure.

[0045] In case b), procedure 100 can only be carried out by decoding the broadcast signals received by the first 33 and the second 34 antennas. In this case, the broadcast station identifiers are extracted directly from the two broadcast signals received by the antennas via a decoder each, and the audio signal to be transmitted to the listener is derived from one of the two signals received by the antennas, but not from the recombined signal, which would require a third decoder. In this case, only two decoders are needed to carry out the procedure; however, the quality of the audio signal transmitted to the listener during the execution of the procedure is lost, since the audio signal is no longer derived from the recombined broadcast signal. It is therefore of lower quality than in case a).

[0046] It is thus evident that the examples shown above, which avoid the disadvantages of carrying out cases a) and b) and make it possible to obtain a high-quality audio signal using two decoders during the execution of procedure 100, are particularly advantageous and cannot be readily derived from the other general knowledge shared by the present disclosure.

[0047] The application further relates to a computer program product with instructions for carrying out one of the methods described in the present disclosure when this program is executed by a processor.

[0048] Finally, the application relates to a non-volatile, computer-readable storage device on which a program for carrying out one of the methods described in the present disclosure is stored when that program is executed by a processor.

[0049] Method 100, as disclosed herein, thus makes it possible to reliably detect co-channel interference situations by cleverly comparing the broadcast station identifiers decoded from the broadcast signals of two different antennas. Certain examples of Method 100 also make it possible to reduce or even eliminate the disturbances caused by co-channel interference by considering only the broadcast signal of one of the two antennas, for example, by disabling the application of a so-called phase diversity method. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2020 / 007248 A1

[0003] US 2010 / 151809 A1

[0003] US 2016 / 211995 A1

[0003] FR 3064853

[0041] US 8064857

[0041]

Claims

[1] Method (100) for processing multiplexed, frequency-modulated broadcast signals received by a first antenna (33) and a second antenna (34), wherein the method (100) comprises: - the selection (110) in a multiplexed broadcast signal received by the first antenna of a first frequency band of the broadcast signal belonging to a particular channel; - the selection (120) in a multiplexed broadcast signal received by the second antenna of a second frequency band of the broadcast signal belonging to the specified channel; - the decoding (130) of a first broadcast station identifier of the specific channel from the broadcast signal contained in the selected first frequency band; - the decoding (140) of a second broadcast station identifier of the specific channel from the broadcast signal contained in the selected second frequency band; - comparing (150) the first and second radio station identifiers; and - detecting (160) a co-channel interference situation by comparison. [2] Method (100) according to the preceding claim, further comprising a reduction (170) of a quality coefficient previously stored in a memory of a radio receiver, wherein said quality coefficient is associated with a broadcasting station which is assigned to the specific channel as soon as a co-channel interference situation is detected. [3] Method according to any of the preceding claims, further comprising an output (180) of an audio signal derived exclusively from the broadcast signal received by the first (33) or the second antenna (34) as soon as a co-channel interference situation is detected. [4] Method (100) according to any of the preceding claims, further comprising a deactivation (190) of a so-called phase diversity method which recombines the broadcast signals received by the two antennas to improve the audio signal to be output as soon as a co-channel interference situation is detected. [5] Method (100) according to one of the preceding claims, wherein the method is carried out as soon as the probability of co-channel interference being determined by a probabilistic method exceeds a predefined threshold. [6] Method (100) according to any one of the preceding claims, wherein: - the first broadcast station identifier is decoded from a recombination of the broadcast signal contained in the selected first frequency band and the broadcast signal contained in the selected second frequency band; and - The second broadcast station identifier is decoded from the broadcast signal that is contained exclusively in one of the selected first or second frequency bands. [7] Radio receiver (1) comprising at least one first tuner (13) and one second tuner (14), at least one first (15) and one second (16) decoder, a computer (11) and a memory (12); wherein the first (13) and second (14) tuner, the first (15) and second (16) decoder, the computer (11) and the memory (12) are configured to perform the method according to any one of claims 1 to 6. [8] Radio receiver (1) according to the preceding claim, wherein the first tuner (13) is configured to select the first frequency band; the second tuner (14) is configured to select the second frequency band; the first decoder (15) is configured to decode the first broadcast station identifier of the specific channel from the broadcast signal contained in the selected first frequency band; the second decoder (16) is configured to decode the second broadcast station identifier of the specific channel from the broadcast signal contained in the selected second frequency band; and the computer (11) is configured to compare the first and second broadcast station identifiers and to detect a co-channel interference situation from the comparison. [9] Radio apparatus (2) comprising a radio receiver (1) according to one of claims 8 or 9. [10] Motor vehicle (3) comprising a radio set (2) according to the preceding claim or a radio receiver (1) according to one of claims 8 or 9.

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