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

Abstract

The invention relates to a method for monitoring a wireless multichannel 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) wirelessly exchange audio data in a time-division multiple access (TDMA) method; this wireless transmission is performed on the basis of repeating frames (SF); each frame (SF) comprises a number (A) of time slots (SL); 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); each audio stream transmitted in the frame (SF) occupies a number (T) of the time slots (SL) of the frame (SF); the base station (400) transmits control data (201) to the mobile devices (300) for controlling the wireless transmission. The at least two mobile devices (300) are paired with the base station (400) and then each communicate via an encrypted wireless transmission via their respective audio links using the corresponding audio link parameters. A wireless audio monitoring unit (360) is paired with the base station (400) so that the wireless audio monitoring unit (360) can participate in the encrypted wireless transmission. At least one parameter set of audio link parameters of at least one of the audio links of the at least two mobile devices (300) is transmitted from the base station (400) to the wireless audio monitoring unit (360). Audio link parameters of a selected audio link of one of the mobile devices (300) are set by the wireless audio monitoring unit (360). Audio data is received by the wireless audio monitoring unit (360) via the set audio link of one of the mobile devices (300), and the received audio data is output by the wireless audio monitoring unit (360).

Description

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

[0002] The present invention relates to a method for monitoring 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] The German Patent and Trademark Office has searched the following document in the priority-establishing German patent application: CN 1 14 071 438 A. It is an object of the present invention to provide a wireless multi-channel audio system which enables improved monitoring.

[0005] This object is achieved by a method for monitoring a wireless multi-channel audio system according to claim 1 and by a wireless multi-channel audio system according to claim 10. 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 in a Time Division Multiplex Access (TDMA) format. This wireless transmission is based on 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.A wireless audio link exists between each of the mobile devices and the base station, over which the audio stream is transmitted. The at least two mobile devices are paired with the base station and can then communicate via an encrypted wireless transmission using their respective audio links with the corresponding audio link parameters. Each of the at least two mobile devices communicates with the base station via an independent audio link.

[0006] After the wireless audio monitoring unit has paired with the base station so that the wireless audio monitoring unit can participate in the encrypted wireless transmission, the base station transmits at least two sets of audio link parameters of the audio links of the at least two mobile devices via the encrypted wireless transmission. One of the at least two audio links is selected, and based on the received set of parameters, the wireless audio monitoring unit sets the transmission parameters so that it can receive the audio data transmitted in the selected audio link. The received audio data is decoded and can then be output.

[0007] This creates a possibility in the wireless multi-channel audio system whereby, for example, a sound engineer can use the wireless audio monitoring unit to listen in on or monitor each of the audio links between a mobile device and the base station. This wireless audio monitoring unit then receives all audio data from the mobile device or from the base station according to the selected audio link. This audio data can be decoded and output by the monitoring unit, so that the sound engineer or the user of the monitoring unit is able to listen to the audio stream transmitted in the audio link. The user of the wireless audio transmission unit is thus able to check or listen to the audio data directly transmitted from an audio link.This allows the monitoring unit user to easily determine or verify whether the transmitted audio data (data from an audio transmitter such as a wireless microphone or audio data from the base station to one of the in-ear monitoring units) is correct. The base station transmits control data and / or parameters for the audio link to the mobile devices to control the respective wireless transmission.

[0008] According to one aspect of the present invention, the wireless transmission takes place in frequency ranges 470 - 698MHz (UHF) or 1350 - 1525MHz (1 G4).

[0009] The monitoring unit monitors the wireless audio transmission system, namely monitoring the audio links between the mobile devices and the base station.

[0010] According to a further 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.

[0011] Pairing between the base station and the mobile devices or the monitoring unit is performed by the base station sending a control time slot on an RF channel, the mobile device or the wireless audio monitoring unit searching for an RF signal, detecting the RF signal on the RF channel and reading the control time slot, sending an identifier of the mobile device or the wireless audio monitoring unit on the RF channel to the base station and confirming the identifier of the mobile device or the wireless audio monitoring unit.

[0012] According to one example, a list of audio links is created in the form of a station list and transmitted to the wireless audio monitoring unit. The wireless audio monitoring unit can select an audio link based on the list.

[0013] According to one example, the wireless transmission represents an encrypted transmission with a session identifier in the form of a session key.

[0014] A symmetric key can be used to enable encrypted communication between the base station and the mobile devices or the monitoring unit. The key exchange (e.g., during the pairing process) between the base station and the mobile devices is carried out using a public / private key method. The encrypted transmission can be based on a session identifier. Therefore, there is no point-to-point encryption, but only session encryption with a session key, for example, to enable multicasting.

[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] 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).

[0017] Further embodiments of the invention are the subject of the subclaims.

[0018] Advantages and embodiments of the invention are explained in more detail below with reference to the drawing.

[0019] Fig. 1 shows a schematic diagram of a wireless multi-channel audio system, and

[0020] Fig. 2 shows a representation of time slots of different wireless transmitters which are received by the wireless receiver.

[0021] 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.

[0022] If multiple audio transmitters (e.g., a handheld microphone or other microphones) simultaneously transmit audio signals to a base station, and the base station transmits a second audio signal composed of these audio signals to an in-ear monitoring unit, a bodypack, or a beltpack, the microphones do not transmit simultaneously. Instead, subscriber access is achieved using a Time Division Multiple Access (TDMA) system with a repeating frame containing a number of time slots per RF channel. For example, 128 time slots per frame can be allocated for the transmission of audio streams. Additional time slots can be allocated for control data. This allows up to 128 mobile devices to communicate with the base station.

[0023] The TDMA method ensures multiple access to a wireless audio transmission through the temporal sequencing of multiple participants. The minimum latency of the audio data is determined by the largest separation between two consecutive time slots.

[0024] Fig. 1 shows a schematic representation of a wireless multi-channel audio system. The wireless multi-channel audio system WMAS 100 is based, for example, on ETSI EN 300422 and comprises 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 or beltpack (mobile receiver) 350 with an input for microphone signals and an output for in-ear monitoring. Thus, the number of mobile transmitters 310, 320 or mobile receivers 330, 340, 350 in the wireless multi-channel audio system 100 can vary.

[0025] 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.

[0026] A control console 500 connected to the base station 400 can provide a user interface 510, via which an operator can enter configuration and control commands for the base station 400. Optionally, the base station 400 can be coupled to a mixing console 600. Using the mixing console 600, the audio signals from the respective wireless audio transmitters (e.g., microphones) can be mixed into an overall audio signal. The audio transmission system 100 has at least one wireless audio monitoring unit 360. The monitoring unit 360 is configured to listen to at least one of the audio links between the mobile devices 300 and the base station 400, i.e., to receive and play back the audio stream transmitted in this audio link. The monitoring unit 360 can thus listen to or listen to the audio link.This enables a sound engineer to listen to the audio links between the mobile devices 300 and the base station 400 in order to check their quality.

[0027] The monitoring unit 360 can be configured as a mobile device that can receive and play back an audio stream from or for the mobile devices. In particular, the monitoring unit can be configured as a wireless receiver 330, 340, 350 (e.g., with an in-ear monitoring function).

[0028] The base station 400 can wirelessly transmit the audio link parameters of the respective audio links to the monitoring unit 360 as control data 203. Using these audio link parameters, the monitoring unit 360 can listen in on one of the audio links, i.e., it receives the audio data of the respective audio stream from the wireless transmitters or the base station in the respective time slots and can compile and play back this audio data.

[0029] To implement the function of the wireless audio monitoring unit 360, no modification of the mobile devices 310-350 is required. The mobile devices each send or receive audio data of an audio stream via an audio link between the mobile device 300 and the base station 400. If the monitoring unit 360 has the audio link parameters available, it can listen to the audio stream transmitted via the audio link because it can receive the audio data transmitted by the mobile device 300 or the base station 400.

[0030] The list of audio links and audio link parameters can be compiled by the operator of the control software for the wireless audio monitoring unit. This list is comparable to a station list. This list does not necessarily have to contain all of the audio links used, as the user of the wireless audio monitoring unit should only be able to hear a selection. After the station list (with the audio links) has been created, it is transmitted to the wireless audio monitoring unit, the base station, and / or one of the mobile devices. 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 or audio stream.The mobile receiving device 350 can additionally be equipped with a microphone input for a clip-on microphone or lavalier microphone. This enables the user of the mobile receiving device 350 to simultaneously receive one audio channel or audio stream and transmit another audio channel or audio stream. 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 after every 16 time slots. This time slot can 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 free 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 can be connected to the base station 400 and can have a user interface (UI) 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 include 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 or beltpack 350 (receiving unit) can communicate with the base unit 400 in the form of a bidirectional radio transmission. The microphone data that the bodypack or beltpack 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 a 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. Audio transmission can occur in the frequency ranges 470–698 MHz (UHF) or 1350–1525 MHz (1 G4), specifically in the following frequency bands: TV-UHF (470–608 MHz); TV-UHF China (470–510 MHz and 630–698 MHz); L-Band CEPT (1350–1400 MHz); L-Band USA (1435–1525 MHz).

[0042] Subscribers access the transmission channels using Time Division Multiple Access (TDMA). Optionally, the number of subscribers can be up to, for example, 128 independent audio streams per broadband channel. The modulation method can be Orthogonal Frequency Division Multiplexing (OFDM) in combination with various subcarrier modulation or coding methods. The audio coding can be done using different methods and sampling rates, as well as in mixed mode. For example, the sampling rates can be 48 kHz or 96 kHz. The audio coding can be done using the OPUS method, the ADPCM method, the PCM method, or other suitable coding methods (e.g., LC3, SBC). Synchronization of the TDMA raster and the carrier offset estimation (CFO estimation) can be ensured using synchronization patterns. A basic TDMA frame can be divided into 1 / 2, 1 / 4, 1 / 8, or 1 / 16 access intervals.

[0043] The audio transmission can be encrypted. The base station 400 can provide a synchronization signal, manage connected or paired devices, and allocate the corresponding communication resources. The base station 400 can generate audio signals from the received audio signals from the wireless transmitters, which can represent a mixture of the audio signals from the wireless transmitters. These audio signals can then represent an in-ear monitoring audio signal. 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 should communicate. The monitoring unit 360 can also register with the base station to enable communication with the base station 400.

[0044] It may be necessary for the mobile devices to be "paired" with the base station. Pairing can take place in several steps. First, the operator decides which frequency the base station will use to provide the RF channel. Optionally, the base station can be set up 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 far as possible. The base station transmits a control timeslot on the RF channel within a frame. The control timeslot contains a unique ID for the base station. After the pairing process has been initiated on the mobile devices, for example by pressing a button, the mobile device searches for an RF signal, finds the RF channel of the base station and reads the control timeslot.In another control time slot, the mobile device then sends its unique ID to the base station, where it is displayed as a device ready for pairing. The base station operator confirms that the mobile device has been found, and the base station saves the mobile device's unique ID. The mobile device receives an acknowledgement from the base station in the next control time slot 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. The audio transmission method can be used for any TDMA audio transmission; in particular, a transmission of audio signals from at least two audio channels can occur from a base station to a receiver. An example of such a wireless multi-channel audio system is in-ear monitor systems, where the base station or a mixer mixes an audio signal based on multiple audio channels and then transmits this signal wirelessly to in-ear monitoring units.

[0047] 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.

[0048] Bodypacks can output a stereo signal at the audio output.

[0049] Each receiver of the audio samples can check whether the audio samples contained in the frame are intended for it or not. The base station can transmit the information about which time slot is intended for a mobile device in advance in the control data. This can be particularly important in a multi-channel audio system, for example, when more than two audio channels are transmitted.

[0050] For each of the TDMA resources (i.e., for each stream, frame, or time slot) 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 time slots provided in a frame. In other words, the transmission parameters can be configured for each audio stream.

[0051] The audio data transmitted in a stream can be transmitted uncompressed or compressed. The required data rate for uncompressed transmission is determined by 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 decrease the data rate at the expense of audio quality. When using audio codecs, it is important to ensure that they have a processing latency. This latency can be, for example, 10 ms. The respective TDMA resource used also affects the power consumption of the mobile devices and the base station. The more TDMA resources required for a stream (sending / receiving), the higher the power consumption. Using an audio codec can also lead to an increase in power consumption.

[0052] For example, with an efficient OPUS codec, good audio quality can be achieved at a data rate of approximately 80 kbit / s. In wireless transmission, this data rate can be achieved if 8 of, say, 128 TDMA slots are used with a low modulation (e.g., BPSK). This would also be advantageous in terms of robust modulation at a long range. Alternatively, this data rate of 90 kbit / s can be achieved if one of 128 time slots in a frame is used with a high modulation (e.g., QAM 64). Such a stream would have high modulation at a short range and higher latency. The advantage, however, is that the lower resource requirements for this stream can lead to the unused TDMA resources being used for another channel.

[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 (e.g., during the pairing process) between the base station and the mobile devices is carried out using a public / private key method.

[0054] Fig. 2 shows a representation of time slots from various wireless transmitters received by the wireless receiver. In the TDMA method, each audio transmitter is assigned a time slot within a frame. In Fig. 2, eight time slots SL1–SL8 are provided per frame SF. However, this is only an example for illustration purposes. Thus, eight time slots SL1–SL8 can be transmitted per frame. The time slots SL1–SL8 are repeated in each frame SF.

[0055] 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 S0. In the example in Fig. 2, the first stream S1 requires 2 / 8 of the resources, stream S2 requires 4 / 8, and stream S3 requires 1 / 8 of the resources. 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 not used.

[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] In a further embodiment of the invention, when setting up the audio links via the control console 500, each audio link can be assigned its own selectable name. This can be, for example, the name of an artist who is to use the mobile device or a role in a theater performance. The names are entered at the console or read from a prepared file. These names then become part of the list of audio link parameters and are transmitted to the base station 400. When configuring the paired mobile devices, the base station wirelessly transmits the associated names as part of the control data 201 to the respective mobile device. The mobile device can have a display on which this name is shown. Optionally, the list of audio link parameters, including the names, can be transmitted to the wireless audio monitoring unit 360 via control data 201 during operation.The list of labels can then be displayed on a display belonging to the wireless audio monitoring unit 360, allowing a user of the wireless audio monitoring unit 360 to use the labels to select the signal from the mobile device whose audio data they wish to listen to. Optionally, when transmitting the list of audio link parameters to the wireless audio monitoring unit 360, the base station 400 can only use the data from those mobile devices that are currently transmitting audio data. Alternatively, the information regarding whether an audio link is currently in use can be transmitted along with a complete list of audio link parameters, and the wireless audio monitoring unit 360 will only display the labels of the active audio links. This simplifies the selection of the audio signal to be listened to, as there is no need to skip labels of currently unused audio links.Especially in stage applications, any simplification of operation is an important contribution to ensuring the smooth running of a show. List of reference symbols.

[0058] 100 wireless multi-channel audio system

[0059] 200 antenna

[0060] 201 Control data 202 Cable

[0061] 203 Audio Link Parameters

[0062] 300 mobile devices

[0063] 310 handheld microphone (mobile transmitter)

[0064] 311 first audio data 320 multi-channel microphone (mobile transmitter)

[0065] 321 second audio data

[0066] 330 first bodypack or beltpack (mobile receiver)

[0067] 331 audio data

[0068] 340 second bodypack or beltpack (mobile receiver) 341 audio data

[0069] 350 mobile receiver

[0070] 351 third audio data

[0071] 360 Wireless Audio Monitoring Unit Base Station Control Console Mixer

Claims

Claims 1. A method for monitoring 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 in an audio link, and at least one base station (400), wherein each of the at least two mobile devices (300) and the base station (400) exchange audio data wirelessly using a Time Division Multiplex Access (TDMA) method, wherein each of these wireless transmissions 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 at least once per frame (SF) in at least one time slot (SL) in the respective audio link, wherein each audio stream transmitted in the frame (SF) occupies a portion (T) of the time slots (SL) of the frame (SF),wherein the base station (400) transmits control data (201) to the mobile devices (300) for controlling the wireless transmission, wherein the at least two mobile devices (300) are paired with the base station (400) and then each communicate via an encrypted wireless transmission via their respective audio links with the corresponding audio link parameters, wherein each of the at least two mobile devices (300) communicates with the base station (400) via an independent audio link, comprising the steps of: Pairing a wireless audio monitoring unit (360) with the base station (400) so that the wireless audio monitoring unit (360) can participate in the encrypted wireless transmission, Transmitting at least two parameter sets of audio link parameters of the audio links of the at least two mobile devices (300) from the base station (400) to the wireless audio monitoring unit (360), Select one of at least two audio links, Setting audio link parameters of a selected audio link of one of the at least two mobile devices (300) by the wireless audio monitoring unit (360), Receiving audio data via the set audio link of one of the mobile devices (300) by the wireless audio monitoring unit (360), and Outputting the received audio data by the wireless audio monitoring unit (360).

2. A method for monitoring a wireless multi-channel audio system (100) according to claim 1, wherein the audio link parameters include a transmission frequency and / or an indication of which of the time slots belong to the selected audio link in order to determine the position of the audio data of the selected audio link.

3. A method for monitoring a wireless multi-channel audio system (100) according to claim 1 or 2, wherein the wireless transmission takes place in frequency bands 470 MHz - 698 MHz or 1350 - 1525 MHz.

4. A method for monitoring a wireless multi-channel audio system (100) according to one of claims 1 to 3, wherein the mobile devices (300) are 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.

5. A method for monitoring a wireless multi-channel audio system (100) according to any one of claims 1 to 4, wherein the base station (400) has a monitoring mode in which the base station (400) transmits parameters for the audio links of the mobile devices (300) to the wireless audio monitoring unit (360).

6. A method for monitoring a wireless multi-channel audio system (100) according to any one of claims 1 to 4, wherein the wireless audio monitoring unit (360) is configured as a wireless receiver.

7. A method for monitoring a wireless multi-channel audio system (100) according to any one of claims 1 to 6, wherein pairing between the base station (400) and one of the mobile devices (300) or the wireless audio monitoring unit (360) is performed by: Sending a control time slot on an RF channel by the base station (400), Searching for an RF signal by the mobile device (300) or the wireless audio monitoring unit (360), Detecting the RF signal on the RF channel and reading the control time slot, sending an identifier of the mobile device (300) or the wireless audio monitoring unit (360) on the RF channel to the base station (400), Confirm the identification of the mobile device (300) or the wireless audio monitoring unit (360).

8. A method for monitoring a wireless multi-channel audio system (100) according to any one of claims 1 to 7, wherein a list of the audio links is created in the form of a station list and transmitted to the wireless audio monitoring unit (360), wherein the wireless audio monitoring unit (360) selects an audio link based on the list.

9. A method for monitoring a wireless multi-channel audio system (100) according to one of claims 1 to 8, wherein the wireless transmission represents an encrypted transmission with a session identifier in the form of a session key.

10. A wireless multi-channel audio system (100), comprising at least two mobile devices (300), each for transmitting and / or receiving audio data in the form of at least one audio stream in an audio link, at least one base station (400), and a wireless audio monitoring unit (360) configured to monitor the wireless transmission from a mobile device (300) to the base station (400) or from the base station (400) to one of the mobile devices (300), wherein the mobile devices (300) and the base station (400) are configured 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, wherein each mobile device (300) transmits or receives audio data of an audio stream in at least one time slot at least once per frame,wherein each audio stream transmitted in the frame occupies a portion (T) of the time slots of the frame, wherein the base station (400) is configured to transmit control data to the mobile devices for controlling the wireless transmission, wherein the at least two mobile devices (300) are paired with the base station (400) and then each communicate via an independent and encrypted wireless transmission via their respective audio links with the corresponding audio link parameters, wherein the base station (400) and the wireless audio monitoring unit (360) are configured to perform a pairing so that the wireless audio monitoring unit (360) can participate in the encrypted wireless transmission, wherein the base station (400) is configured to output parameter sets of audio link parameters of the at least two audio links of the at least two mobile devices (300) to the wireless audio monitoring unit (360), wherein the wireless audio monitoring unit (360) is configured to select one of the at least two audio links so that the audio data transmitted in the selected audio link can be received and output.

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