GB2607973A

GB2607973A - Method and system for providing public announcements

Info

Publication number: GB2607973A
Application number: GB2110782.6A
Authority: GB
Inventors: Sali Hemant; Doyle Roger
Original assignee: Bombardier Transportation GmbH
Current assignee: Alstom Transportation Germany GmbH
Priority date: 2021-06-11
Filing date: 2021-07-27
Publication date: 2022-12-21
Also published as: GB202110782D0

Abstract

A method for providing public announcements in a vehicle for public passenger transport, in particular a railway vehicle, includes establishing a wireless data connection between a mobile device 1, which stores a voice message, and an audio system 5, 6 of the vehicle using a signalling protocol for initiating, maintaining, and terminating real-time sessions for voice applications via a VoIP Server 4, transferring the voice message as a VoIP message (VM) from the connected mobile device 1, to the audio system 5, 6 using the signalling protocol, and converting the VoIP message (VM) into the public announcement using the audio system 5, 6. The signalling protocol may comprise session initiation protocol (SIP) and the transfer may use RTP.

Description

METHOD AND SYSTEM FOR PROVIDING PUBLIC ANNOUNCEMENTS Technical field 100011 The present invention relates to methods and systems for providing public announcements in a vehicle for public passenger transport, in particular a respective railway vehicle.

Background

100021 Many vehicles for public passenger transport are equipped with an announcement system for providing live messages such as such as safety announcements, status announcements, and connecting travel announcements to the passengers by a driver or another crew member such as a steward or a conductor, For example, analog lines may be used for making public announcements by a crew member from fixed locations in the vehicle.

100031 Further, document US 10 171 556 B2 describes systems and methods for transferring a public announcement message to an onboard public announcement system (OPAS) installed on a vehicle using a personal electronic device. The personal electronic device establishes a wireless network connection to the OPAS to transmit a public announcement message stored on a personal electronic device. The personal electronic device transmits the public announcement message to the OPAS via the wireless network connection. The personal electronic device may download messages from a remote public announcement server for transfer to the OPAS. The personal electronic device may also record messages and control the playback of messages on the OPAS.

100041 Furthermore, document EP 2 874 860 B1 describes an operating system for operating functional units in a rail vehicle. At least one base station is provided in each car of the rail vehicle. Each base station communicates, via a wireless interface, with a mobile terminal of an authenticated user, in particular an authenticated train conductor, who operates functional units of the rail vehicle via a graphical user interface of the mobile terminal. The train conductor has the option of making announcements. Audible announcements may be stored in advance and be activated by the train conductor by operating an appropriate sensitive area of the graphical interface.

100051 The existing solutions for public announcements may be not user-friendly enough, have a comparatively large overhead for recording, storing, transferring, and/or playing the announcements, and/or can only be made from specific static locations in the vehicle.

Problem to be solved 100061 It is an object of the invention to provide methods, systems and devices allowing for high performance at low overhead and/or improved efficiency of public announcement systems, in particular with respect to providing pre-recorded messages with at most short delay (live messages), in terms of time and/or usability. Thus, the user satisfaction and/or the user operability may be enhanced.

100071 Said task is solved by the subject matter of the independent claims.

100081 According to an embodiment of a method for providing public announcements in a vehicle for public passenger transport, in particular a respective railway vehicle, the method includes establishing a data connection between a mobile device, which stores a voice message, and an audio system of the vehicle using a signaling protocol configured for initiating, maintaining, and terminating real-time sessions for voice applications, transferring the voice message as Voice over IP (VoIP) message from the connected mobile device to the audio system using the signaling protocol, and converting the VoIP message into the public announcement using the audio system.

100091 The spoken message is typically not pre-recorded (prior to connecting the mobile device to the VoIP server), i.e. a live message.

100101 Further, at least the performance of public announcements in public transport vehicle may be improved due to using VoIP technology.

100111 The mobile device may be a smart phone or a tablet computer.

100121 Further, the mobile device may be a personal electronic device of a person, in particular an employee such as the conductor or another crew member. This typically means that the person has to log in to the mobile device prior to providing the public announcements. As such the personal electronic device may also be provided by the employer, e.g. a railway company.

100131 This facilitate making pre-recorded announcements in different vehicles For example, a conductor may use the same mobile device in different trains for making (prerecorded) announcements, such as emergency announcements but also typical normal (frequently recurring) announcements 100141 In particular, the mobile device may be a personal smart phone or a tablet computer.

100151 Typically, the mobile device allows for recording and storing respective voice messages that may later be transferred as VoIP message to the audio system.

100161 In other words, prior to establishing the data connection between the mobile device and the audio system, the voice message may be recorded using the mobile device and/or stored on the mobile device. For example, the data connection may be established after recording the voice message. Alternatively, the data connection may be established after downloading the voice message from another device.

100171 Further, the mobile device typically includes a storage storing a web application or a mobile application which may be used for one or more of the following functions: establishing a data connecting to a VolP server, connecting to the VoIP server, recording a spoken message, storing the recorded message, converting the stored message into a VoIP message, transferring the converted VoIP message to the VoIP server, and optionally converting the spoken message on the fly into the VoIP message and/or transferring the converted message VoIP message on the fly to the VoIP server.

100181 The term "app" as used herein shall embrace the terms web application" and "mobile application" 100191 The term server" as used herein shall refer both to a computer program (software) and a device providing functionality for other programs or devices, typically called "clients", in particular to a respective device including the software for providing server functionality (for clients) in a network, in particular a network using the internet protocol suite, Transmission Control Protocol / Internet Protocol (TCP/IP) and/or User Datagram Protocol / Internet Protocol (UDP/IP). In the following a device providing server functionality in a network is also referred to as "host" 100201 The signaling protocol typically includes the session initiation protocol (SIP) for initiating, maintaining, and terminating real-time sessions, and the real-time transport protocol (RIP), in particular the secure real-time transport protocol (SRTP) for transferring the VoIP message as respective data stream. Further, signaling protocol typically includes the session description protocol (SDP) for describing session parameters and/or metadata referring to the Vol? message. Accordingly, transferring of the VoIP message from the mobile device to the audio system can be achieved with very low overhead and at most short time delay.

100211 Alternatively, the signaling protocol may be based on or include other protocols such as RFC 4566, a 11.323. However, these protocols typically require a larger overhead.

100221 The data connection between the mobile device and the audio system is typically established via a VoIP server of the vehicle using the signaling protocol.

100231 In particular, establishing the data connection between the mobile device and the audio system may include establishing a first data connection between the mobile device and the VoIP server using the signaling protocol, and establishing a second data connection between the VoIP server and the audio system. Typically, the VoIP server initiates establishing the second data connection with the audio system using the signaling protocol (after the first data connection is established).

100241 The VoIP sewer may e.g. be provided by a Crew Communication Gateway (CCG) which acts as a SPOC (Single point of contact) for mobile devices to connect to the train and get the desired functionalities such as Public Address, play pre-recorded messages, internal communication, and/or passenger communication.

100251 In these embodiments, the CCG may host the VoIP server to carry out the VoIP functionality and may employ SIP over RTP/SRTP.

100261 Note that the VoTP sewer may also be implemented as a logical device, for example as part of a controller of the audio system 100271 The mobile device may by wirelessly connected to a wireless interface of the vehicle which is connected to the VoIP sewer, a wireless router of the vehicle which connected to the VoIP sewer, or any other device of the vehicle connected to the VoIP sewer and providing a wireless interface for communication with the mobile device. In other words, the mobile device may be (wirelessly) connected to a Wi-Fi network of the vehicle (which is different from the local area network of the vehicle).

100281 Accordingly, connecting the mobile device to the server typically includes connecting the mobile device to and/or via the wireless interface or the wireless router of the vehicle, and/or the other device providing the wireless interface.

100291 Further, connecting the mobile device to the server may include logging in on the server, e.g. using a username and a password that may be provided by or via the app.

100301 Accordingly, it may not be required to registered the mobile device on a terminal within the vehicle. However, the mobile device is typically pre-registered as crew-member device.

100311 The wireless interface may include a eless) router and one or more wireless access points.

10032] The server, the audio system, and the wireless interface (in particular the wireless access point(s) and/or the wireless router) are typically connected with each other via a local area network of the vehicle, in particular a local area network that is a wired data network and/or uses the Internet Protocol and/or Ethernet technology.

100331 For example, the local area network may use coaxial cable, twisted pair links and/or fiber optic links in conjunction with switches as a shared medium for information transfer.

100341 Accordingly, communication and/or transferring the VoIP message to the sewer may be facilitated.

100351 The VoIP server and the app may support different languages, and are typically configured for a specific language in these embodiments, for example a preselected language such as English. This facilitate communication.

100361 Typically, the mobile device communicates with the VoIP server using SIP (in particular RFC 326 I), and wherein the VolP server communicates with the audio system using SIP (in particular RFC 3261).

100371 The VoIP message is typically transmitted from the mobile device to the server using a real time transmission protocol (RTP), in particular a secure real time transmission protocol (SRTP) for safety reasons.

100381 Further, the VoIP message is typically transmitted from the server to the audio system using RTP, in particular SRTP 100391 In other words, the respect VoIP-functionality is typically implemented via SIP and RTP, in particular using SIP and SRTP, and supplemented by the session description protocol SDP 100401 Accordingly, the VoIP server typically provides SIP-server functionality and VoIP-server functionality.

[0041] Likewise, the mobile device (the app) and the audio system typically provide a SIP-agent functionality, and SIP-user agent functionality, respectively.

100421 Further, the mobile device (the app) and the audio system may provide a VoIP-agent functionality.

100431 Typically, establishing the first and second data connections includes sending a connection request "SIP INVITE' and receiving a response message "SIP 200 OK".

100441 More particular, the mobile device may initiate establishing the data connection with the audio system using the signaling protocol (SIP and SDP if desired) via the VoIP server by sending a connection request "SIP INVITE" to the VolP server. Upon successfully receiving the connection request from the mobile device, the VoIP server may send a connection request "SIP INVIIE" to the audio system using the signaling protocol (SIP and SDP if desired). Upon successfully receiving the connection request from the VoIP server, the audio system may send a response message "SIP 200 OK" to the VoIP server using the signaling protocol (SIP). Upon successfully receiving the response message "SIP 200 OK" from the audio system, the VoIP server may send a response message "SIP 200 OK" to the mobile device using the signaling protocol (SIP). This may be auto attended.

100451 Upon successfully establishing the data connection between the mobile device and the audio system, and the first and second data connection, respectively (upon successfully receiving the response message "SIP 200 OK" from the VoIP server), the mobile device may start transferring the voice message as VoIP message to the audio system via the VoIP server, typically using RTP.

100461 If all data of the VoIP message are sent by the mobile device, transferring may be ended using the signaling protocol (SIP).

100471 In particular, the connected mobile device may send an end message "SIP BYE" to the audio system via the VolP server.

100481 More particular, the connected mobile device may send an end message "SIP BYE" to the VoIP server. Upon successfully receiving the end message "SIP BYE" from the mobile device, the VoliP sewer may send an end message "SIP BYE" to the audio system Upon successfully receiving the end message "SIP BYE' from the WO server, the audio system may send a (further) response message "SIP 200 OK' to the VoIP server using the signaling protocol (SIP). Upon successfully receiving the response message "SIP 200 OK" from the audio system, the VoIP server may send a (further) response message "SIP 200 OK-to the mobile device using the signaling protocol (SIP).

100491 Alternatively, the VoIP server does not wait for the response message "SIP 200 OK" from the audio system, but sends the (further) response message "SIP 200 OK" to the mobile device immediately and thereafter (on completion of sending the VoIP message to the audio system and making the announcement, respectively) send an end message "SIP BYE" to the audio system.

100501 In this way, a particularly fast and/or efficient transferring the voice message as Volt) message with very low overhead only can be provided 100511 Note that transmitting the \TAP message from the VoIP sewer to the audio system may be started (initiated) prior to completely receiving the VoIP message from the mobile device at the Vold) server.

100521 Converting the VoIP message into a corresponding public announcement may include converting the Vold) message into an analog audio signal.

100531 The analog audio signal may be broadcast in the vehicle, typically using loudspeakers of the audio system.

100541 Further, converting the VoIP message and/or broadcasting the analog audio signal may be initialized even prior to finishing transferring (completely transferring) the Val) message to the audio system.

100551 A delay between establishing the data connection and starting converting the VoIP message and/or broadcasting the analog audio signal may be equal to less than a predefined and/or configurable value.

100561 In particular, the delay be smaller than or equal to about 2 s, more typically 1 s or even 0.75 s (predefined second value) to avoid unwanted long delay times in emergencies. However, this may depend on the network bandwidth.

100571 The VoIP message may be converted into the analog audio signal by a controller of the audio system, an audio converter of the audio system, in particular a train amplifier of the audio system, or at least one loudspeaker of the audio system.

100581 In the latter embodiment, the loudspeaker(s) may also provide SIP-and Vo1P-functionality. In other words, the VoIP message may also be transferred from a controller of the audio system to a loudspeaker or loudspeakers of the audio system, wherein the loudspeaker(s) is(are) configured to convert the VoIP message (VM) into a respective analog audio signal, these loudspeakers support VoIP and host a respective SIP agent.

100591 Typically, the mobile device, the VoIP server and the controller or the audio converter of the audio system provides SIP-functionality and VoIP-functionality, and the controller or the audio converter of the audio system is connected to simple analog loudspeaker(s).

100601 According to an embodiment of a system for providing public announcements in a vehicle for public passenger transport, in particular a respective railway vehicle, the system includes a wireless interface provided by a vehicle for public passenger transport, and connected to a local area network of the vehicle, a mobile device storing a voice message and connectable to the local area network via the wireless interface, and an audio system provided by the vehicle. The audio system is connectable with the local area network, configured to receive, in a connected state, the voice message as VoIP message from the mobile device, when connected to the local area network, using a signaling protocol configured for initiating, maintaining, and terminating real-time sessions for voice applications. Further, the audio system is configured to at least contribute in converting the VoIP message into the public announcement.

100611 The local area network is typically a wired data network and/or uses the Internet Protocol and/or Ethernet technology.

100621 Typically, the system includes a VoIP server provided by the vehicle and connectable to the local area network.

100631 The mobile device may communicate with the audio system via the VoIP server using the signaling protocol.

100641 Further, the VoIP sewer may communicate with the audio system using the signaling protocol.

100651 The VoIP sewer may in particular be configured to communicate with one, typically both of the audio system and the mobile device using a protocol providing at least one of, typically all of encryption, message authentication, integrity, and optionally replay attack protection. The real time transmission protocol is typically implemented as a secure real time transmission protocol (SRTP).

100661 The VoIP server may be provided by one or more computer devices of a passenger comfort system of the vehicle, the computer(s) hosting the VolP server and typically bridging the Wi-Fi network of the vehicle and the local area network of the vehicle.

100671 In case the existing computing devices of the comfort system does not allow for hosting the VoIP server due to technical reasons, a new computing device may be added to the comfort system to host the VoIP server.

100681 As already explained above, the mobile device may be a smartphone, a tablet computer or the like.

100691 The mobile device may include (store) an app which is, when running on the mobile device, configured to initialize establishing a first data connection with the VoTP sewer, and initialize transferring the voice message as VolP message to the audio system and the VoTP server, respectively.

100701 Likewise, the VoIP server is typically configured to establish a second data connection with the audio system, typically after the first data connection between the mobile device and the VoIP server has been established.

100711 The audio system may include an audio converter configured to convert the VolP message into an analog audio signal, in particular a train amplifier.

100721 Alternatively, the loudspeaker(s) of the audio system may be configured to convert the VoIP message into the analog audio signal.

100731 Further, at least one of the VolP server, the audio converter and the controller (5) of the audio system are implemented as a respective logical device.

100741 Typically, the system is configured to perform the methods as explained herein.

100751 According to an embodiment of a vehicle for public passenger transport, in particular a respective railway vehicle, the vehicle includes a local area network, a device connected to the local area network and providing a wireless interface for a mobile device storing a voice message, such as a wireless router optionally connected with wireless access point, an VolP server connected to the local area network as explained herein, and an audio system connected with the VoLP server via the local area network, and configured to receive a VaLP message from the server and to convert the VoLP message into an analog audio signal, in particular an audio system as explained herein.

100761 A mobile device, in particular a mobile device as explained herein may be connectable to the Vol? sewer via the wireless interface provided by the vehicle and connected with the local area network 100771 Typically, the desired functionality is provided by an app when running on the mobile device.

100781 The (running) app may provide or facilitate one or more or even all of the following features/functi onaliti es: Public Address Manual Public Announcement; Play pre-recorded emergency/normal message, Internal Communication: Full duplex VoIP communication, typically between a conductor using the mobile device and fixed driver's handset in the train cabs or between two mobile devices using full duplex communication using VolP; Passenger Communication: VolP communication between conductor using a mobile device and passenger who operated Call For Aid (CFA) at a CFA device; and View/Display existing alarms such as CFA, PEA (Passenger Emergency Alarm), EEH (Emergency Egress Handle) 100791 Other embodiments include on one or more computer-readable storage media, and one or more computer programs recorded on the one or more computer-readable storage media or computer storage devices, and configured to perform the processes of the methods described herein.

100801 In particular, a computer program and/or a computer-readable storage medium may include instructions which, when executed by a one or more computing units (processors) of a system, in particular a public announcement system disposed in a public transport vehicle, cause the system to carry out the processes of the methods explained herein.

100811 The above-described embodiments can be combined with each other in any way if not specified otherwise. Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.

Brief description of the figures

100821 The attached drawings illustrate embodiments and together with the description serve to explain the principles of the invention. The elements of the drawings are shown relative to each other and are not necessarily to scale.

100831 The same reference numbers denote similar or even equal components.

100841 FIG. IA is a block diagram schematically illustrating a system providing public announcements according to embodiments.

100851 FIG 1B is a block diagram schematically illustrating a system providing public announcements according to embodiments.

100861 FIG. 2A is a block diagram schematically illustrating a system providing public announcements according to embodiments.

100871 FIG. 2B illustrates a flow chart of a method for providing public announcements according to embodiments.

100881 FIG 2C illustrates a flow chart of a method for providing public announcements according to embodiments

Detailed description

100891 FIG. IA is a block diagram schematically illustrating a system 100 for providing public announcements.

100901 In the exemplary embodiment, system 100 includes a wireless interface 23, a VolP server 4 and an audio system 5 arranged in a passenger train 101. As indicated by the dashed-dotted arrows in Fig. 1A, wireless interface 2 for providing a Wi-Fi network of train 101, VoliP server 4 and the audio system 5 are connected with each other via a local area network of the train.

100911 A mobile device 1 storing a voice message, in particular a mobile device of a conductor or another crew member of train 101 is connectable to the local area network via the wireless interface 23, and, when connected to the Wi-Fi network, to initiate establishing, via server 4, a data connection with audio system 5, 6.

100921 For example, the (pre-registered) mobile device 1 of the conductor may wirelessly connect with the trains network which is provided by mobile accessible router (MAR) and access points such as WLAN-access points of train 100 100931 The voice message(s) may be stored on mobile device 1 in any suitable format, for example as a respective way-file or more typically in a compressed format such as ogg mp3 or m4a.

100941 After establishing, the data connection with audio system 5, 6, i.e. a data connection having a first data connection between mobile device 1 and server 4 (through wireless interface 32) and a second data connection between server 4 and audio system 5, 6, mobile device 1 may send the stored voice message as VolP message VM via server 4 to audio system 5, 6 100951 In the exemplary embodiment, audio system 5, 6 includes a controller 5 or a converter 5 and a loudspeaker 6 connected with the controller or converter 5, typically a plurality of loudspeakers 6.

100961 The controller or converter 5, which is in the following also referred to as audio control device, may be configured to receive via the local area network the VoIP message V M from server 4.

100971 Typically, controller or converter 5 hosts a SIP agent for this purpose (public announcements) 100981 Likewise, mobile device I typically also hosts a respective SIP agent, for example as a part of an app, in particular a mobile app running on mobile device 1 100991 In one embodiment, controller or converters is configured to convert the received Vol? message VNI into an analog audio signal AM and to broadcast the analogue audio message AM via loudspeaker(s) 6.

1001001 Alternatively, or in addition, controller or converter 5 may be used for forwarding the VoIP message VNI to one or more loudspeaker(s) 6 host a SIP agent and configured to convert the VoIP message VM into an analogue audio signal and broadcast the analogue audio signal.

[001011 In other words, the public address SIP agent(s) on the audio system 5, 6 may, typically as per an audio system configuration, convert the VoIP message into an analog audio signal using the SIP agent of the controller or converter 5 and the announcement may be made by (analog) loud speaker(s) 6 of the audio system 5, 6 connected to the controller or converter 5, and/or the VoIP message may be forwarded to or even directly be send (as indicated by the arrow between VoIP server 4 and loud speaker 6 in Fig. 1A) from the VoIP server 4 to loud speaker(s) 6 hosting a respective (separate) sip agent for converting the VoIP message in the analogue audio signal prior to and/or during making the announcement by the loud speaker(s) 6 of the audio system 5, 6. When the SIP agent of the controller or converter 5 is used, the VoIP message may only be converted once into the analog audio signal. A mixed configuration having both simple analog loudspeakers and loudspeakers with sip agents is also possible.

1001021 As indicated by the dashed rectangle in Fig. 1A, sewer 4 and controller/converter may be provided by one physical device and are implemented as respective logical devices, respectively.

[00103] Note that the SIP agents on audio system 5, 6 typically auto attend to incoming calls for public address (public announcements).

[00104] Thereafter server 4 may transfer the recorded Vol? message to the public address SIP agent of audio system 5 using an RIP protocol, in particular an SRTP protocol.

1001051 In other embodiments, the audio system includes or consists of at least one loudspeaker 6 hosting a sip agent, and the VoIP server 4 may directly transmit the VoIP message to the at least one loudspeaker 6.

1001061 FIG. 1B is a block diagram schematically illustrating a system 200 for providing public announcements. The system 200 is similar to the system 100 explained above with regard to figure IA, However, audio control device 5 of system 200 is connected with two exemplary loudspeakers 6, 7, for example a cab loudspeaker 6 and a saloon loudspeaker 7.

1001071 Typically, audio control device 5 is connected with plurality of loudspeakers 6, 7.

1001081 Further, it is illustrated in figure 1B that the wireless interface 23 of train 201 typically consists of a router 3 and at least one wireless access point 2.

1001091 As further illustrated in figure 2A illustrating a system 300 for providing public announcements, two, more typically a plurality of wireless access points 2, 2' may be distributed within the train 301.

1001101 Accordingly, the mobile device I of a conductor may have access to the local area network of train 301 from at least almost any point within the train 301.

1001111 Further, another crew member, e.g. a further conductor may use a further mobile device 11 to make public announcements via server 4 as indicated by the VoIP message VIVI' in figure 2A.

1001121 FIG. 2B illustrates a flow chart of a method 1000 for providing public announcements in a vehicle, in particular a train.

1001131 In a block 1100, a mobile device storing a voice message initiates, typically via Vol? server of the vehicle, a data connection with an audio system of the vehicle using a signaling protocol configured for initiating, maintaining, and terminating real-time sessions for voice applications.

1001141 The mobile device is typically a mobile device of a crew member and/or pre-registered at the VAR server.

1001151 In a subsequent block 1200, the voice message as VoIP message is transferred from the mobile device to the audio system using the signaling protocol, typically via the VolP server, 100116] In a block 1300 that may be subsequent to block 1200 as indicated by the time arrow t, the VoIP message is converted into the public announcement by the audio system 1001171 As indicated by the dashed-dotted rectangle 1300, converting the VoIP message may include a block 1310 of converting the VoIP message into an analog audio signal, and a subsequent block 1320 of broadcasting the analog audio signal in the vehicle, typically using loudspeakers of the audio system.

1001181 It is however also possible that broadcasting 1320 the public announcement already starts prior to finishing converting in block 1310 or even prior to finishing transferring in block 1200.

1001191 As indicated by block 1010, the voice message may be recorded and stored on the mobile device prior to establishing the data connection in block 1100.

1001201 FIG. 2C shows a flow chart of a method 1000' for providing a public announcement in a vehicle for public passenger transport that is similar to method 1000 explained above with regard to Fig. 2B, Method 1000' also includes corresponding blocks 1100, 1200 and 1300 for establishing 1100 the data connection, transferring 1200 the voice message as VoIP message and converting 1300 the VoIP message into the public announcement.

1001211 However, method 1000 is more specific with respect to using the SIP and Vol? signaling protocol(s) 1001221 In the exemplary embodiment, the mobile device 1 initiates establishing 1100 the data connection with the audio system 5 using SIP by sending a connection request "SIP INVITE" to the audio system 5 in a block 1110, typically via the VolP server 4 sending a "SIP INVITE" to the audio system 5 upon receiving the connection request from the mobile device 1 1001231 In response, the audio system 5 may send a response message "SIP 200 OK" to the mobile device 1 using SIP in a block 1120, typically via the VoIP server 4 sending a "SIP 200 OK" to the mobile device 1 upon receiving the response message from the audio system.

1001241 Thereafter, mobile device 1 may start playing and transferring the recorded voice message as VoIP message to the audio system 5 using RTP, in particular SRTP, typically via the Val'. server 4 in a block 1205 1001251 When the VolP message is completely transmitted from mobile device 1, mobile device may, in a block 1210, stop playing and send an end message SIP BYE to the audio system 5 using SIP, typically via the Vol? server, and the audio system 5 may, upon receiving the end message SIP BYE, send a response message SIP 200 OK back to the mobile device 1 in a block 1220, typically via the VoIP server 4.

1001261 Note that blocks 1120 and 1220 are typically similar. This typically also applies to blocks 1110 and 1210 except for the different send codes -SIP INVITE' and "SIP BYE", respectively.

1001271 As further illustrated in Fig. 2C, converting 1310 the VolP message into an analog audio signal and/or broadcasting 1320 may start prior to block 1210 or even prior to block 1220.

[00128] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof List of reference numbers 1, l' mobile device 2, 2' wireless access point 3 (wireless) router 23 wireless interface 4 host / server audio system 6, 7 loudspeaker 100, 200, 300 system 101, 201, 301 vehicle, train 1000-1320 method steps AM analog audio signal VM, VA/I' Voice over LP message / VolP message

Claims

Claims 1 A method (1000, 1000') for providing a public announcements in a vehicle for public passenger transport, in particular in a respective railway vehicle (101, 201, 301), the method comprising: establishing (1100) a data connection between a mobile device (1, 1'), which stores a voice message, and an audio system (5-7) of the vehicle (101, 201, 301) using a signaling protocol for initiating, maintaining, and terminating real-time sessions for voice applications; transferring (1200) the voice message as Vali message (VM) from the connected mobile device (1, 1') to the audio system (5-7) using the signaling protocol, and converting (1300) the VoIP message (VM) into the public announcement using the audio system (5-7) 2 The method of claim 1, wherein the signaling protocol comprises the session initiation protocol, SIP, for initiating, maintaining, and terminating real-time sessions, and the real-time transport protocol, RTP, in particular secure real-time transport protocol, SRTP, for transferring the VoIP message (VM) as respective data stream, and/or the session description protocol, SDP, for describing session parameters and/or metadata referring to the VoIP message (VM).3 The method of any preceding claim, wherein the data connection between the mobile device (1, 1') and the audio system (5-7) is established via a VoIP server (4) of the vehicle (101, 201, 301) using the signaling protocol, wherein establishing (1100) the data connection between the mobile device (1, 1') and the audio system (5-7) comprises establishing a first data connection between the mobile device (1, 1') and the VoIP server (4) using the signaling protocol, and establishing a second data connection between the VoIP sewer (4) and the audio system (5-7), wherein the voice message is transferred as VoIP message (VM) from the connected mobile device (1, 1') to the audio system (5) via the VoIP server (4), and/or wherein the VoIP server (4) establishes a data connection with the audio system (5) using the signaling protocol.4, The method of any preceding claim, wherein establishing (1100) the data connection the mobile device (1, 1') to the VoIP server (4) comprises wirelessly connecting the mobile device to a wireless access point (2) of the vehicle (101, 201, 301) and/or a wireless router (23) of the vehicle (101, 201, 301), the wireless access point (2) and/or the wireless router (23) being connectable with the audio system (5), typically via the VoIP server (4), and/or via alocal area network of the vehicle (101, 201, 301), in particular a local area network which is implemented as a wired data network and/or uses the Internet Protocol and/or Ethernet technology.The method of claim 3 or 4, wherein the mobile device (1, 1') communicates with the VoLP server (4) using SIP, and wherein the VoIP server (4) communicates with the audio system (5) using SIP.6 The method of claim 5, wherein the transferring (1200) of the voice message as VoIP message (VM) from the mobile device (1, 1') via the VoLP server (4) to the audio system (5) uses RTP, and is initiated after successfully connecting the VoLP server (4) to the audio system (5).7 The method of any preceding claim, wherein the mobile device (1, 1') initiates establishing (1100) the data connection with the audio system (5, 6, 7) using the signaling protocol, in particular SIP, typically via the VoIP server (4), by sending (1110) a connection request (SIP INVITE) to the audio system (5, 6, 7), typically via the VoIP server (4), and wherein the audio system (5, 6, 7), upon receiving the connection request, sends (1120), on or after successfully receiving the connection request (SIP INVITE), a response message (SIP 200 OK) to the mobile device (1, 1') using the signaling protocol, in particular SIP, typically via the VoIP server (4).8 The method of any preceding claim, wherein the connected mobile device (I, I upon receiving the response message (SIP 200 OK) from the audio system (5), typically via the Von' server (4), starts (1205) transferring the voice message as VoLP message (VM) from the connected mobile device (1, 1') to the audio system (5) using the signaling protocol, in particular RTP, typically via the VoIP server (4), wherein the connected mobile device (1, 1') sends (1210) an end message (SIP BYE) to the audio system (5, 6, 7) using the signaling protocol, in particular SIP, typically via the VoLP server (4), when the VoIP message (VM) is completely transmitted from the mobile device (1, 1'), and wherein the audio system (5, 6, 7), upon receiving the end message (SIP BYE), sends (1220) a response message (SIP 200 OK) to the mobile device (1, 1') using the signaling protocol, in particular SIP, typically via the VoIP server (4) 9 The method of any of claims 2 to 8, wherein the VoIP message (VM) is transmitted from the VoIP server (4) to the audio system (5) prior to completely receiving the VoIP message (VNI) from the mobile device (1, 1').10. The method of any preceding claim, wherein converting (1300) the VoIP message (VM) comprises converting (1310) the VoIP message (VM) into an analog audio signal (AIV1), and/or broadcasting (1320) the analog audio signal in the vehicle, typically using loudspeakers (6, 7) of the audio system (5-7).11. The method of any preceding claim, wherein converting (1300) the VoIP message (VM) and/or broadcasting (1400) the analog audio signal is initialized prior to finishing transferring the VoIP message (VM) to the audio system (5).12 The method of any preceding claim, prior to establishing (1100) the data connection between the mobile device (1, 1') and the audio system (5, 6, 7), comprising (1010) recording the voice message with the mobile device (1, 1') and/or storing the voice message on the mobile device (1, 1').13. The method of any preceding claim, after successfully converting the VoIP message (VM) into the analog audio signal (AM), further comprising transferring an end message to the audio system (5) from the connected mobile device (1, 1') using the signaling protocol, typically via the VoIP server (4).14 The method of any preceding claim, wherein the VoIP message (VM) is converted into the analog audio signal (AM) by a controller (5) of the audio system (5,6,7), an audio converter of the audio system (5,6,7), in particular a train amplifier of the audio system (5,6,7), or at least one loudspeaker (6, 7) of the audio system (5, 6, 7) The method of any preceding claim, wherein at least one of the mobile device (1, 1'), the audio system (5,6,7) and the VoIP server (4) provides SIP-functionality and VoIPfunctionality.6. A system (100, 200, 300) for providing a public announcement in a vehicle for public passenger transport, the system comprising: a wireless interface (2, 23) provided by the vehicle (101, 201, 301), and connected to a local area network of the vehicle (101, 201, 301); - a mobile device (1, 1') storing a voice message and connectable to the local area network via the wireless interface (2, 23), and an audio system (5) provided by the vehicle (101, 201, 301), connectable with the local area network, configured to receive, in a connected state, the voice message as VoLP message (VN1) from the mobile device (1, 1'), when connected to the local area network, using a signaling protocol for initiating, maintaining, and terminating real-time sessions for voice applications, and configured to convert the VoIP message (VM) into the public announcement.17 The system of claim 16, wherein the system comprises a VoLP sewer (4) provided by the vehicle (101, 201, 301) and connectable to the local area network, wherein the mobile device (1, 1') communicates with the audio system (5-7) via the VoIP server (4) using the signaling protocol, wherein the VoIP server (4) communicates to the audio system (5) using the signaling protocol, and/or wherein the VoIP server (4) is configured to establish a second data connection with the audio system (5-7), typically after a first data connection between the mobile device (1, 1') and the VoIP server (4) has been established.18. The system of claim 16 or 17, wherein the mobile device (1, 1') is a smartphone or a tablet computer, and/or wherein the system is configured to perform the method of any of the claims Ito 15 19. The system of any of the claims 17 to 18, wherein the mobile device (1, 1') comprises an app which is, when running on the mobile device (1, 1'), configured to: - initialize establishing a first data connection with the VoIP sewer (4); and - initialize transferring the voice message as VoIP message (VM) to the audio system (5-7), typically via the VoIP sewer (4).20. The system of any of the claims 16 to 19 wherein the local area network is a wired data network and/or uses the Internet Protocol and/or Ethernet technology.21. The system of any of the claims 16 to 20, wherein at least one of the VoIP server (4), the mobile device (1, 1'), the app, and the audio system (5,6,7) is configured to use at least one of a session initiation protocol, SIP, and a real time transmission protocol, RTP, and a session description protocol, SDP.22 The system of claim 21, wherein the VoIP server (4) is configured to communicate with the audio system (5-7) and/or the mobile device (1, 1') using a protocol providing at least one of, typically all of encryption, message authentication, integrity, and replay attack protection, and/or wherein the real time transmission protocol is implemented as a secure real time transmission protocol, SRTP.23. The system of any of the claims 16 to 22, wherein at least one of the mobile device, the app, the audio system (5), a controller (5) of the audio system (5, 6, 7), and a loudspeaker (6, 7) of the audio system (5) is operable as SIP-user agent.24 The system of any of the claims 17 to 23, wherein the VoIP server (4) is provided by one or more computer devices of a passenger comfort system of the vehicle (101, 201, 301), wherein the audio system (5,6,7) comprises an audio converter configured to convert the VolP message (VIVI) into an analog audio signal (AM), in particular a train amplifier, wherein the loudspeaker (6, 7) of the audio system (5) is configured to convert the VoIP message (VIVI) into the analog audio signal (AM), and/or wherein at least one of the Von) server (4), the audio converter and the controller (5) of the audio system (5, 6, 7) are implemented as a respective logical device 25. The system of any of the claims 16 to 24, wherein the vehicle (101, 201, 301) is a railway vehicle.