Method for controlling a wireless multichannel audio system, and wireless multichannel audio system

Abstract

The invention relates to a method for controlling a wireless multichannel audio system (100). The multichannel audio system (100) has: at least two mobile devices (300) for transmitting and / or receiving audio data in the form of at least one audio stream; and at least one base station (400). The mobile devices (300) and the base station (400) exchange audio data in the form of an audio stream using Time-Division Multiplex Access (TDMA). This wireless transmission is carried out on the basis of repeating frames (SF). Each frame (SF) has a number A of time slots (SL). Each mobile device (300) transmits or receives audio data of an audio stream at least once per frame (SF) in at least one time slot (SL). Each audio stream transmitted in the frame (SF) occupies a portion (T) of the time slots (SL). The base station (400) transmits control data to the mobile devices (300) for controlling the wireless transmission.

Description

[0001] Method for controlling a wireless multi-channel audio system and wireless multi-channel audio system

[0002] The present invention relates to a method for controlling a wireless multi-channel audio system and a wireless multi-channel audio system.

[0003] Wireless multi-channel audio systems are known from ETSI EN 300422. This type of audio system uses multiple channels for audio transmission. Multiple wireless transmitters (e.g., wireless microphones) and multiple wireless receivers (e.g., in-ear monitoring units) can communicate simultaneously with a base station.

[0004] It is an object of the present invention to provide a wireless multi-channel audio system which enables improved transmission of multiple audio streams.

[0005] This object is achieved by a method for controlling a wireless multi-channel audio system according to claim 1 and by a wireless multi-channel audio system according to claim 7.

[0006] Thus, a method for controlling a wireless multi-channel audio system is provided. The multi-channel audio system has at least two mobile devices for transmitting and / or receiving audio data in the form of at least one audio stream and at least one base station. The mobile devices and the base station exchange audio data in the form of an audio stream using Time Division Multiplex Access (TDMA). This wireless transmission occurs on the basis of repeating frames. Each frame has a number A of time slots. Each mobile device transmits or receives audio data of an audio stream at least once per frame in at least one time slot. Each audio stream transmitted in the frame occupies a portion of the time slots. The base station transmits control data to the mobile devices for controlling the wireless transmission.

[0007] According to one aspect of the present invention, the wireless transmission takes place in the frequency ranges 470-698 MHz (UHF) and 1350-1525 MHz (1 G4). According to another aspect of the present invention, the mobile devices can be wireless transmitters or wireless receivers. The wireless transmitters can be configured as wireless microphones, and the wireless receivers can be configured as in-ear monitoring units.

[0008] The mobile devices can transmit information to the base station via a return channel or within a time slot during the transmission of an audio stream. This information can represent, for example, the battery status, signal strength, etc. The base station can use one of the time slots in the frame to transmit control signals to the mobile devices. In this time slot, the base station can transmit additional information, such as an instruction to change frequency.

[0009] If interference is detected by a mobile device or the base station, it may be advisable to change the frequency used to transmit the audio stream. The base station can use a timeslot, such as a control timeslot, to transmit information about the frequency change.

[0010] Alternatively, if the base station has detected interference and changed its transmit and receive frequencies, a mobile device may not yet have detected this change and continue to transmit on the old transmit frequency. However, if the mobile device does not receive a control timeslot with information in a frame, the mobile device knows that the base station has changed the frequency. After the mobile device has changed the frequency and notified the base station of this via control data or in a timeslot, communication between the base station and the mobile device can proceed based on the new frequency.

[0011] If the mobile device isn't aware of the new transmission frequency or frequency band, it can start a scan until it finds the corresponding frequency or frequency band. The mobile device can then tune into the new frequency band.

[0012] Optionally, the mobile device can stop transmission on the old frequency band as soon as it detects that the base station is no longer transmitting on that frequency band. This is advantageous because unwanted signals can be reduced on the old frequency band. Optionally, the mobile device can store multiple backup frequencies or frequency bands, which the mobile device can then search for a signal from the base station. If this is not the case, the mobile device can initiate a station scan.

[0013] According to one aspect, the base station can transmit information about the new frequency band or the new transmitter frequency to the mobile device in a control time slot before the base station switches to the new frequency. This is advantageous because it allows the mobile device to switch frequencies more quickly. This can be particularly relevant if the frequency change is to take place during a live transmission.

[0014] The dynamic frequency switching capability allows the wireless multi-channel audio system to respond dynamically to any interference. In the event of interference with a frequency or frequency band, the transmission frequency can be switched to another interference-free frequency within seconds. Optionally, the base station can transmit a frequency switch command to the mobile devices, provided the frequency interference allows transmission. Otherwise, the mobile device can automatically switch to a new frequency band as soon as it no longer receives data from the base station on the old frequency or frequency band.

[0015] The invention also relates to a wireless multi-channel audio system with at least two mobile devices for transmitting and / or receiving audio data in the form of at least one audio stream and at least one base station. The mobile devices and the base stations exchange data wirelessly using a TDMA method. This wireless transmission is based on repeating frames, each frame having a number A of time slots. Each mobile device transmits audio data of an audio stream at least once per frame in at least one time slot. Each audio stream transmitted in the frame has a portion of the time slots of the frame. The base station transmits control data to the mobile devices for controlling the wireless transmission.

[0016] A wireless multi-channel audio system is provided, e.g., in accordance with ETSI EN 300422. The audio system comprises a plurality of mobile devices, which may be configured as wireless transmitters, wireless receivers, or wireless transceivers. The multi-channel audio system may, e.g., comprise at least one mobile audio transmitter, at least one mobile audio data receiver, and a wireless base station, which receives audio data in the form of an audio stream from the audio data transmitters and transmits audio data in the form of an audio stream to the mobile audio data receiver using a Time Division Multiplex Access (TDMA) method. If multiple audio data transmitters are provided in the system, the audio streams of these audio data transmitters may be transmitted in time slots within a frame using the TDMA method.

[0017] Before interrupting transmission in the current frequency band, the base station can transmit frequency change information, in particular the new frequency band, in one of the control time slots so that the mobile device knows the new frequency band and no longer needs to start a scan.

[0018] The mobile devices can be designed as wireless microphones, e.g. handheld microphones, wireless stereo microphones or wireless instrument microphones, as wireless receivers (e.g. in-ear monitoring units) or as wireless transmitters / receivers (e.g. in-ear monitoring units with a microphone connection).

[0019] Further embodiments of the invention are the subject of the subclaims.

[0020] Advantages and embodiments of the invention are explained in more detail below with reference to the drawing.

[0021] Fig. 1 shows a schematic representation of a wireless multi-channel audio system,

[0022] Fig. 2 shows a representation of time slots of different wireless transmitters which are received by the wireless receiver, and

[0023] Fig. 3 shows a schematic representation of a frame during the transmission of audio data.

[0024] Wireless multi-channel audio systems (WMAS) are known, for example, from ETSI EN 300422. Several mobile devices, such as several microphones or several in-ear monitoring units, can be used simultaneously with a base station.

[0025] If multiple audio transmitters (e.g. a handheld microphone or other microphones) transmit audio signals to a base station simultaneously, and the base station transmits a second audio signal composed of these audio signals to an in-ear monitoring unit or a bodypack or beltpack, the microphones do not transmit simultaneously. Instead, subscriber access is achieved using a Time Division Multiple Access TDMA system with a repeating frame with a number of time slots per RF channel. For example, 128 time slots per frame can be provided for the transmission of audio streams. The transmission duration is, for example, 1 ms. Additional time slots can be provided for control data. This allows up to 128 mobile devices to communicate with the base station.

[0026] The TDMA method ensures multiple access to a wireless audio transmission by scheduling multiple participants. The minimum latency of the audio data is determined by the largest separation between two consecutive time slots.

[0027] Fig. 1 shows a schematic representation of a wireless multi-channel audio system. The wireless multi-channel audio system WMAS 100 is based on ETSI EN 300422 and has a base station 400, at least one antenna 200, and a plurality of mobile devices 300, e.g., at least one handheld microphone (mobile transmitter) 310, optionally at least one multi-channel microphone (mobile transmitter) 320, optionally a first bodypack or beltpack (mobile receiver) 330 with an output for in-ear monitoring, optionally a combined second bodypack (mobile receiver) 350 with an input for microphone signals and an output for in-ear monitoring. A bodypack or beltpack 340 symbolizes that additional mobile receivers can be provided. In particular, more mobile receivers than mobile transmitters can be provided. Thus, the number of mobile transmitters 310, 320 or mobile receivers 330, 340, 350 in the wireless multi-channel audio system 100 may vary.

[0028] In the wireless multi-channel audio system 100, the base station 400 is connected to an antenna 200 via a cable 202 and provides an RF channel. Optionally, additional antennas can be connected to the base station 400, which can provide additional RF channels. The antenna 200 can have an RF transmitter ("radiohead"), so that digital signals are transmitted via the cable 202, which are converted into analog RF signals in the radiohead.

[0029] A control console 500 connected to the base station 400 can provide a user interface through which an operator can enter configuration and control commands for the base station 400. Optionally, the base station 400 can be coupled to a mixer 600. Using the mixer 600, the audio signals from the respective wireless audio transmitters (e.g., microphones) can be mixed into an overall audio signal.

[0030] The wireless multi-channel audio system 100 can, for example, have a number of microphones, namely a handheld microphone 310, a multi-channel or stereo microphone 320, and mobile receiving devices 330, 340, 350. The mobile receiving devices 330-350 can have an output for so-called in-ear monitoring, which allows a wearer to receive an audio channel. The mobile receiving device 350 can additionally be equipped with a microphone input for a clip-on microphone or lavalier microphone. The user of the mobile receiving device 350 is thus able to simultaneously receive one audio channel and transmit another audio channel. The microphones 310, 320 and mobile receiving devices 330-350 are collectively referred to below as mobile devices. In other applications, more or fewer mobile devices than those shown in Fig. 1 can be integrated into the wireless multi-channel audio system 100.

[0031] The microphone 310 can send first audio data 311 in the form of an audio stream to the base station 400. The second microphone 320 can send second audio data 321 in the form of an audio stream to the base station 400. The mobile device 350 (bodypack or beltpack) can send third audio data 351 in the form of an audio stream to the base station 400 (via the antenna 200). The mobile devices 330 and 340 can receive audio data 331, 341 in the form of an audio stream from the base station 400.

[0032] The base unit 400 can transmit control data 201 to the respective mobile devices, e.g., transmitter / receivers 310, 320, 330, 340, 350, via the antenna 200. The control data 201 can be used by the mobile devices 310-350 to set wireless transmission parameters. Using the control data 201, the base station 400 can specify transmission parameters, such as a transmission frequency, a time slot in the transmission frame, a transmission power, etc., to the mobile devices 300. The base station 400 can thus control the transmission from the mobile devices to the base station 400 and from the base station 400 to the mobile devices 300.

[0033] The control data 201 may include control and / or status information exchanged between the mobile devices and the base station. In addition to the control information or control data, further data may be exchanged as part of the control data 201. For example, in a case with 128 TDMA time slots per frame, one time slot may be reserved every 16 time slots. This time slot may be used for control data such as synchronization information and control and status signals.

[0034] Optionally, a frame can have 128 TDMA time slots for audio transmission and 8 time slots for control signals, so that a frame has, for example, 136 time slots.

[0035] Alternatively, the control data can also be transmitted in those time slots that are not reserved and therefore free. In this case, no separate time slots are reserved for the transmission of the control data; instead, the control data is transmitted depending on the availability of unused time slots.

[0036] The communication from the base station 400 to the mobile devices 340, 350 can be carried out in a multicast and the communication from the mobile devices 310, 320 to the base station 400 can be carried out in a unicast.

[0037] The control console 500 may be connected to the base station 400 and may have a user interface (User Interface U1) by means of which the user can enter configuration and / or control commands for the base station 400.

[0038] The (handheld) microphone 310 can wirelessly transmit audio data as the first audio data 311 in the form of an audio stream as a unidirectional radio transmission to the base station 400. This transmission 311 can be carried out in a unicast. The audio transmission can be carried out in the form of mono microphone data.

[0039] The microphone 320 can transmit audio signals 321 as an audio stream in the form of a unidirectional radio transmission. Stereo or multi-channel microphone data can be transmitted in a unicast. The first and / or second bodypacks 330, 340 (mobile receiving units) can receive a unidirectional radio transmission (audio data 331, 341) from the base station 400. This radio transmission can include, for example, in-ear monitoring data. The audio data 331, 341 can be composed of the audio data 321, 311 from the two microphones 310, 320 and, optionally, additional audio data. This data can be transmitted as a unicast or multicast from the base station 400. The bodypack 350 (receiving unit) can communicate with the base unit 400 in the form of a bidirectional radio transmission. The microphone data that the bodypack has received via the microphone input is transmitted to the base station 400, for example as unicast or multicast.In-ear monitoring data is transmitted from the base station 400 as unicast or multicast.

[0040] The audio data from the respective audio data transmitters (microphones 310, 320) can be transmitted using a TDMA method. The TDMA method ensures multiple access to a wireless audio transmission through the temporal sequencing of multiple participants. For low-latency transmission, for example, a deterministic and equidistant grid of time slots per audio stream can be used. The minimum latency of an audio stream is determined by the largest distance between two consecutive time slots assigned to it.

[0041] The wireless multi-channel audio system 100 can have a channel bandwidth of 6 MHz, 8 MHz, or 10 MHz. Transmission occurs, for example, in the frequency ranges 470-698 MHz (UHF) and 1350-1525 MHz (1 G4).

[0042] The modulation method can be orthogonal frequency division multiplexing (OFDM) combined with various subcarrier modulation or coding methods. Audio coding can be performed using various methods and sampling rates, as well as mixed mode. For example, sampling rates can be 48 kHz or 96 kHz. Audio coding can be performed using the OPUS method, the ADPCM method, the PCM method, an LC3 or SBC method, or another suitable method. Synchronization of the TDMA raster and the carrier offset estimation (CFO estimation) can be ensured using synchronization patterns.

[0043] The audio transmission can be encrypted. Base station 400 can provide a synchronization signal, manage connected or paired devices, and allocate the corresponding communication resources. Base station 400 can generate audio signals from the received audio signals from the wireless transmitters, which can represent a mix of the audio signals from the wireless transmitters. These audio signals can then represent an in-ear monitoring audio signal.

[0044] The mobile devices 300, 310 - 350 can register with the base station 400 to enable communication with the base station 400. The mobile devices 310 - 350 can optionally initiate the transmission of audio data if they have previously detected a base station 400 with which they are to communicate. This may require the mobile devices to be "paired" with the base station. Pairing can take place in several steps. First, the operator decides at which frequency the base station will provide the RF channel. Optionally, the base station is configured to identify other transmitters in the permitted frequency band so that the operator can select the frequency for the RF channel so that interference from other transmitters is avoided as much as possible. The base station transmits a control time slot within a frame on the RF channel.The control timeslot contains a unique ID of the base station. After the pairing process has been initiated on the mobile devices, for example by pressing a button on the respective mobile device, the mobile device searches for an RF signal, finds the RF channel of the base station and reads the control timeslot. In another control timeslot, the mobile device then sends its own unique ID to the base station and is displayed there as a device that is ready for pairing. The base station operator confirms the found mobile device and the base station saves the mobile device's unique ID. The mobile device receives a confirmation from the base station in the next control timeslot and in turn saves the base station's unique ID.

[0045] Optionally, the base station operator can complete the pairing process by verifying the mobile device's PIN code. Only after pairing are the mobile devices ready to transmit a signal. Typically, a sound engineer pairs the mobile devices with the base station before a production, preventing unpaired devices from eavesdropping at a later time. Furthermore, the base station cannot process signals from unpaired devices.

[0046] According to one aspect, the mobile devices 310 - 350 can also optionally communicate with each other and exchange data.

[0047] The audio transmission method can be used in a TDMA audio transmission, in which a transmission from a base station to a receiver comprises audio signals from at least two audio channels. An example of such a wireless multi-channel audio system is in-ear monitor systems, where the base station transmits an audio signal based on multiple audio channels to in-ear monitoring units.

[0048] The base station must therefore have audio data with multiple (at least two) audio channels. These audio channels can come from an external source or from wireless microphones in the multi-channel audio system. Bodypacks or beltpacks can output a stereo signal at the audio output.

[0049] Each recipient of the audio samples can check whether the included audio samples are intended for them or not. This can be particularly important in a multi-channel audio system, for example, when more than two audio channels are transmitted.

[0050] For each TDMA resource (i.e., for each stream) in the audio transmission system, the RF modulation used for wireless transmission can be specified. Examples of RF modulation are Q-PSK or QAM 64. While Q-PSK modulation allows for greater robustness against interference and greater directivity, QAM 64 modulation enables higher data rates. The total available data rate for a stream is then determined by the RF modulation used and the number of available time slots in a frame.

[0051] The audio data transmitted in a stream can be transmitted uncompressed or compressed. The required data rate for uncompressed transmission of an audio channel is the product of the sample rate (e.g., 48 kHz, 96 kHz) and the resolution, e.g., 16 bits. Audio codecs can be used to reduce the data rate. An audio codec can be configured using parameters to increase audio quality at the expense of data rate, or conversely, to increase the data rate at the expense of audio quality. When using audio codecs, it is important to note that they have a processing latency. This latency can be, for example, 10 ms.

[0052] The TDMA resources used also affect the power consumption of the mobile devices and the base station. The more TDMA resources required for a stream (transmit / receive), the higher the power consumption. The use of an audio codec can also lead to an increase in power consumption.

[0053] To meet data protection requirements, communication between the mobile devices and the base station can be encrypted with a symmetric key. The key exchange between the base station and the mobile devices takes place using a public / private key method. Fig. 2 shows a representation of time slots from various wireless transmitters, which are received by the wireless receiver. In the TDMA method, each audio transmitter is assigned a time slot in a frame. In Fig. 2, eight time slots SL1 - SL8 are provided per frame SF as an example. However, this is only an example for illustrative purposes. This means that eight time slots SL1 - SL8 can be transmitted per frame. The time slots SL1 - SL8 are repeated in each frame SF.

[0054] In this example, there are three streams S1, S2, and S3. Each stream is assigned a wireless audio transmitter. Furthermore, the frame SF may contain unused time slots SO. In the example shown in Fig. 2, the first stream S1 requires 2 / 8 of the resources, stream S2 requires 4 / 8, and stream S3 requires 1 / 8.

[0055] The first stream S1 occupies time slots SL4 and SL8. The first, third, fifth, and seventh time slots SL1, SL3, SL5, and SL7 are occupied by the second stream S2. The third stream S3 occupies time slot SL2. The sixth time slot SL6 is unused.

[0056] When transmitting audio data from the respective wireless audio transmitters, it is important that the latency of the respective audio transmission is as low as possible.

[0057] Fig. 3 shows a flow diagram of a method for changing a frequency in a wireless multi-channel audio system. In step S10, interference in the transmission of at least one audio stream is detected. This interference can be detected by the base station or by one of the mobile devices. If the mobile device detects the interference, it can output a corresponding error message to the base station in a return channel or in one of the available time slots. This can occur, for example, if the signal strength detected by the mobile device falls below a threshold, if the bit error rate exceeds a predetermined threshold, or if a signal is detected in a slot that is not normally transmitted.

[0058] Alternatively, the base station can detect interference. If the base station detects interference, it can stop transmitting on the current frequency or frequency band and switch to a new frequency or frequency band. The new frequency can be determined through a scan. Alternatively, the base station can specify a new frequency. The scan can be repeated until a sufficiently interference-free frequency is found. Optionally, the base station can use control data to inform the mobile devices that it intends to change frequency. Optionally, the base station can inform the mobile devices of the new frequency in the control data.

[0059] For example, mobile devices can detect that a change in frequency band or transmission frequency has occurred if the base station is no longer transmitting in the previous frequency band. In particular, the absence of a control time slot or the information transmitted therein can be an indication to the mobile device that the base station has changed frequency.

[0060] If the mobile device detects that the base station is changing frequency, it can, for example, perform a station scan for the new frequency band in step S20. Alternatively, the mobile device can use the information about the frequency band change that the base station previously transmitted, for example, in a control timeslot. If the mobile device then transmits on the new frequency in step S30, this is detected accordingly by the base station, whereby the base station has received confirmation that the mobile device is aware of the frequency band change.

[0061] Optionally, the mobile device can stop transmitting on the current frequency band if it has detected a frequency band change by the base station or if it has received information that a frequency band change is imminent.

[0062] Switching to a new frequency or frequency band can be done using predefined frequency bands. Alternatively, the mobile device can perform a station scan to acquire the new transmission frequency. It can be advantageous if the mobile device knows the new alternative frequency bands in advance. This allows for a faster switch from one frequency band to another.

[0063] Optionally, the mobile device can immediately tune to the new transmission frequency as soon as it becomes aware of the frequency band change. This can occur, in particular, as soon as a transmission from the base station on the original frequency band ends.

[0064] Optionally, a user of the multi-channel audio system can initiate a frequency band change if the base station issues a corresponding error message. Alternatively, the base station can perform a frequency band change automatically.

[0065] Such a frequency band change can also be performed automatically by the base station. In particular, the base station can check whether a pause has occurred in the transmission, allowing a frequency band change to occur without affecting the transmission of the audio stream. In particular, the base station can search for pauses in the audio stream being transmitted. For example, the base station can continuously monitor the levels of the transmitted audio streams.

[0066] A desirable property of the mobile devices is to only transmit data when the mobile device has detected transmission activity from an associated base station. This is particularly important after powering on. The entire wireless multi-channel audio system 100 can, for example, be used at a different location every day on a concert tour. Since this also occurs across national borders, it is possible that a frequency range used the previous day is not permitted for use at the new location. If the mobile devices were to transmit on the last used frequency without prior checking after powering on, this could lead to unauthorized frequency usage. To prevent this, the mobile devices optionally first check after powering on whether there is any transmission activity on the last used frequency from a base station with which the respective mobile device was previously paired.If this is not the case, the mobile device searches alternative frequency ranges for transmission activity from a paired base station in a search mode. The advantage of this feature of mobile devices is that a permissible, available frequency range only needs to be selected at the base station. The base station can then record the transmission activity in this frequency range, and the mobile devices search for this transmission activity without recording any transmission activity themselves. Only when the transmission activity of the paired base station is found does the mobile device begin its own matching transmission activity.

[0067] During later normal operation, this feature of mobile devices can be utilized when an intentional frequency band change occurs due to interference. As soon as a mobile device detects that the paired base station has stopped transmitting on the previously used frequency, the mobile device enters search mode.

[0068] In normal operation, the following possible sequence of events occurs regarding a frequency band change: During normal operation, a check is carried out to determine whether interference is present. Optionally, a time slot can be provided in the time slot transmission in which neither the base station nor an associated mobile device is transmitting. The base station checks in this time slot whether signals are detected in the frequency band in use and whether the signal strength of such interference exceeds a reference value. Optionally, the base station can also perform corresponding measurements in alternative frequency bands in order to find a suitable, free alternative frequency band.

[0069] If a detected interference exceeds the comparison value or upon a corresponding user input, the base station initiates a frequency band change.

[0070] Optionally, the base station sends control data to the mobile devices in the previously used frequency band, indicating which frequency band is being switched to and, if applicable, when the switch will take place.

[0071] If a mobile device has received the control data despite the detected interference, it switches to the new frequency band according to this control data so that transmission can continue immediately in the new frequency band.

[0072] If a mobile device has not received the control data due to interference, it will detect after a short delay that the paired base station is no longer transmitting on the previous frequency. The mobile device will then automatically switch to search mode so that the paired base station's transmission activity can be detected in the new frequency band. Once this is the case, the mobile device will begin transmitting in the new frequency band.

[0073] This makes it possible to perform a frequency band change very effectively within a short period of time. Even if the interference is so severe that individual mobile devices cannot receive the control data for the frequency band change, one implementation has achieved a time span of less than 20 seconds within which all mobile devices have begun transmitting on the new frequency band.

[0074] 100 wireless multi-channel audio system

[0075] 200 antenna

[0076] 201 Control data 202 Cable

[0077] 300 mobile devices

[0078] 310 handheld microphone (mobile transmitter)

[0079] 311 first audio data

[0080] 320 Multi-channel microphone (mobile transmitter) 321 second audio data

[0081] 330 first bodypack (mobile receiver)

[0082] 331 audio data

[0083] 340 mobile receiver

[0084] 341 Audio data 350 second bodypack (mobile receiver)

[0085] 351 third audio data

[0086] 400 base station

[0087] 500 Control console 600 Mixing console

Claims

Claims 1. A method for controlling a wireless multi-channel audio system (100), wherein the system (100) comprises at least two mobile devices (300), each for transmitting and / or receiving audio data in the form of at least one audio stream, and at least one base station (400), wherein the mobile devices (300) and the base station (400) exchange audio data wirelessly using a Time Division Multiplex Access (TDMA) method, wherein this wireless transmission is based on repeating frames (SF), wherein each frame (SF) has a number (A) of time slots (SL), wherein each mobile device (300) transmits or receives audio data of an audio stream in at least one time slot (SL) at least once per frame (SF), wherein each audio stream transmitted in the frame (SF) occupies a portion (T) of the time slots (SL) of the frame (SF), comprising the steps: Detecting a disruption in the transmission of at least one audio stream, initiating a change of a current frequency band for the wireless transmission of the audio streams, Terminating a transmission from the base station (400) in a current frequency band, Transmitting at least control data in at least one time slot by the base station (400) in a new frequency band, and Transmitting data by the mobile device (300) in at least one time slot in the new frequency band to the base station (400) as confirmation of the change of frequency band, wherein the base station (400) uses one of the time slots as a control time slot to transmit control data to the mobile devices (300), and wherein the mobile device (300) detects, based on reception of the control time slot, whether the base station (400) is transmitting in the current frequency band and activates the search for a new frequency band if there is no transmission of the control time slot in the current frequency band.

2. A method for controlling a wireless multi-channel audio system (100) according to claim 1, wherein the mobile device (300) terminates a transmission in a current frequency band when an interruption of the transmission has been detected by the base station (400).

3. A method for controlling a wireless multi-channel audio system (100) according to one of claims 1 to 2, wherein the base station (400) transmits frequency change information, in particular the new frequency band, in one of the control time slots before interrupting the transmission in the current frequency band, so that the mobile device (300) knows the new frequency band and no longer has to start a search, or wherein a search for a new frequency band for the transmission of an audio stream is initiated by the at least one mobile device (300).

4. A method for controlling a wireless multi-channel audio system (100) according to one of claims 1 to 3, wherein the change of the frequency band occurs in response to a user input or automatically.

5. A method for controlling a wireless multi-channel audio system (100) according to one of claims 1 to 4, wherein a change of the frequency band occurs depending on the transmitted audio content of the audio streams, so that the change of the frequency band occurs in such a way that it does not influence, or only slightly influences, a reproduction of the audio data transmitted by the audio streams.

6. A method for controlling a wireless multi-channel audio system (100) according to one of claims 1 to 5, wherein the wireless transmission takes place in the frequency ranges 470-698 MHz (UHF) and 1350-1525 MHz (1 G4).

7. A method for controlling a wireless multi-channel audio system (100) according to one of claims 1 to 6, wherein the mobile devices (300) represent wireless transmitters and / or wireless receivers, wherein the wireless transmitters are configured as wireless microphones and the wireless receivers are configured as in-ear monitoring units.

8. Wireless multi-channel audio system (100), in particular according to ETSI EN 300422, with at least two mobile devices (300) each for transmitting and / or receiving audio data in the form of at least one audio stream and at least one base station (400), wherein the mobile devices (300) and the base station (400) are designed to exchange audio data wirelessly using a TDMA method, wherein the wireless transmission is based on repeating frames, each frame having a number (A) of time slots, each mobile device transmitting or receiving audio data of an audio stream in at least one time slot at least once per frame, each audio stream transmitted in the frame occupying a portion (T) of the time slots of the frame, the base station (400) being configured to initiate a change of a current frequency band for the wireless transmission of the audio streams when interference with the transmission of at least one audio stream in the current frequency band is detected, to terminate a transmission from the base station in a current frequency band, and to transmit control data and / or at least one audio stream in at least one time slot in a new frequency band, the mobile device (300) being configured toTo transmit data in at least one time slot to the base station in the new frequency band as confirmation of the change of the frequency band, wherein the base station (400) is designed to use one of the time slots as a control time slot to transmit the control data to the mobile devices (300), wherein the mobile device (300) is designed to detect, based on the control time slot, whether the base station (400) is transmitting in the current frequency band and is designed to activate the search for the new frequency band if no transmission of the control time slot occurs.

9. Wireless multi-channel audio system (100) according to claim 8, wherein the base station (400) is designed to transmit frequency change information, in particular the new frequency band, in one of the control time slots before interrupting the transmission in the current frequency band, so that the mobile device (300) knows the new frequency band and no longer needs to start a search.

Images