GB2486176A

GB2486176A - An IP packet based communication system which interfaces with external radio and telephony communication networks, suitable for use by the emergency services.

Info

Publication number: GB2486176A
Application number: GB1020433.7A
Authority: GB
Inventors: David Collins; Michael Conroy
Original assignee: SUNGARD PUBLIC SECTOR Ltd
Current assignee: SUNGARD PUBLIC SECTOR Ltd
Priority date: 2010-12-02
Filing date: 2010-12-02
Publication date: 2012-06-13
Also published as: GB201020433D0

Abstract

A communication system (10) comprising a media exchange (12) comprising a primary application server (28) and a primary media server (27), a plurality of media gateways (14) and a plurality of operator terminals (16), wherein the media gateways (14) are configured to transmit and receive signals to and from communications networks external to the communication system (10); the media server (12) is configured to route data between the media gateways (14) and the operator terminals (16) to permit communication between the external communications networks and the operator terminals (16); and the data routed by the media server (12) comprises Internet Protocol (IP) data packets. The communication system is for use by the emergency services, military organisations and highway control agencies. The system also comprises a secondary media exchange (18) comprising a secondary media server (29) and a secondary application server (30) which is operable due to a fault or failure of the primary media server/application server. The primary and secondary media servers may share a single IP address. The application also discloses a radio media gateway for converting radio signals received from a radio network into data packets for transmission in the IP based network and vice versa.

Description

A COMMUNICATION SYSTEM

Technical Field

The present invention relates to a communication system, and in particular to an integrated communication control system for use by organisations such as the emergency services. The present invention also relates to a media server and to a radio media gateway for a communication system.

Background to the Invention

In organisations such as the emergency services, military organisations and highway control agencies communication is vital for effective and efficient operations. Typically such an organisation will have a number of field-based operatives such as patrol and emergency response officers who may be spread out over a wide geographical area.

These operatives are typically provided with a secure radio communications terminal such as a TETRA (Terrestrial Trunked Radio) handset, which may be vehicle mounted or carried by the operative, which can be used to communicate with a central control room or operations centre. The operations centre is manned by operators who receive incoming calls from the public and communicate with and coordinate the field-based operatives to respond to a situation such as an emergency or other incident.

Such organisations typically use Integrated Communication Control Systems (ICCS) in their operations centres to manage the interface between operators and field-based operatives such that the operators can quickly, easily and securely allocate appropriate resources to an incident and coordinate the organisation's response to that incident.

Current ICCS arrangements rely on bespoke hardware, which makes them difficult and costly to maintain, upgrade and expand, since additional bespoke hardware may be necessary to replace out of date or non-functional components. Custom interfaces may

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also be required to connect such systems to existing standard infrastructure, which places a further cost and technical burden on their users.

Additionally, existing ICCS arrangements tend to be physically large, thereby imposing physical requirements on the locations in which they are to be installed. Because of their large size and the amount of bespoke hardware used by existing ICCS solutions they typically also use a large amount of electricity, not only for their own power supplies but also in components such as air conditioning components which are required to cool the components of such systems.

Summary of Invention

According to a first aspect of the invention there is provided a communication system comprising a media server, a plurality of media gateways and a plurality of operator terminals, wherein: the media gateways are configured to transmit and receive signals to and from communications networks external to the communication system; the media server is configured to route data between the media gateways and the operator terminals to permit communication between the external communications networks and the operator terminals; and the data routed by the media server comprises Internet Protocol (IP) data packets.

The communication system of the present invention fully integrates telephone and radio signals in a single Internet Protocol based system which can be physically smaller and can consume less power than known systems. Additionally, as the system is based around Internet Protocol it can easily and quickly be expanded, upgraded or serviced.

The media server may be a primary media server and the communication system may further comprise a secondary media server which is operable in the event of a fault or failure of the primary media server.

Using primary and secondary media servers in this way increases the resilience of the communication system, since the secondary media server can be brought online in the event of a failure or fault of the primary media server to provide continuity of service.

The primary media server and the secondary media server may be configured to communicate with each other such that on detection of a fault or failure of the primary media server the secondary media server is activated.

In this way the secondary media server can be brought online rapidly to take over from the primary media server, thereby minimising loss of audio media.

The primary media server and the secondary media server may share a single IP address such that when the primary media server is active the IP address is assigned to the primary media server and when the secondary media server is active the IP address is assigned to the secondary media server.

The use of a single shared IP address for the primary and secondary media servers allows a seamless transition between the servers, as no modification of data packets is required.

The plurality of media gateways may comprise a telephone media gateway.

The telephone media gateway may be configured to convert signals received from a telephone network to IP data packets and to convert IP data packets received from the media server to signals for transmission to the telephone network.

The plurality of media gateways may comprise a radio media gateway.

The radio media gateway may be configured to convert radio signals received from a radio network to IP data packets and to convert IP data packets received from the media server to signals for transmission to the radio network.

The radio media gateway may be configured to receive signals from and transmit signals to a TETRA network.

The communication system may further comprise an application server.

The radio media gateway may have a plurality of dispatcher interface (DI) ports for connecting the radio media gateway to the radio network.

The application server may be configured to allocate the DI ports of the radio media gateway.

The application server may be a primary application server and the communication system may further comprising a secondary application server which is operable in the event of a fault or failure of the primary application server.

According to a second aspect of the invention there is provided a media server for routing data between media gateways and operator terminals in a communication system to permit communication between the external communications networks and the operator terminals, the media server being connectable to the media gateways by means of an Internet Protocol (IP) network and wherein the data routed by the media server comprises IP data packets.

According to a third aspect of the invention there is provided a radio media gateway comprising means for interfacing the radio media gateway to a radio network, means for interfacing the radio media gateway to an Internet Protocol (IP) based network and means for converting radio signals received from the radio network into data packets for transmission via the IP based network, and for converting data packets received from the IP based network into radio signals for transmission to the radio network.

The means for interfacing the radio media gateway to the radio network may comprise a plurality of dispatcher interface (DI) ports.

The DI ports may be configured for dynamic allocation by an application server of a first communication system to which the radio media gateway is connected, such that in the event that the first communication system is or becomes unavailable the radio media gateway is able to connect to a second communication system associated with the first communication system.

The radio network may be a TETRA network.

Brief Description of the Drawjg

Embodiments of the invention will now be described, strictly by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a schematic representation of a communication system in accordance with an embodiment of the present invention; Figure 2 is a schematic representation illustrating a failover system used in the communication system of Figure 1; Figure 3 is a schematic representation of a typical implementation of an integrated communication control system employing the communication system of Figure 1; Figure 4 is a schematic representation showing the integrated communication control system of Figure 3 in a configuration which may occur when a resource is unavailable; Figure 5 is a schematic representation showing the integrated communication control system of Figure 3 in a configuration which may occur when a different resource is unavailable.

Description of the Embodiments

Referring first to Figure 1, a communication system according to an embodiment of the present invention is shown generally at 10. The communication system 10 is based around a primary media exchange 12 which is connected to a group of media gateways 14 and to a group of operator terminals 16 by means of a computer network such as a local area network (LAN) or a wide area network (WAN). A secondary media exchange 18 is connected to the network and is provided for redundancy, so that in the event of failure of the primary media exchange 12 the secondary media exchange 18 can be brought online to provide continuous operation of the communication system 10. The communication system 10 may be installed, for example, in a control or operations room of an organisation such as a police or ambulance service.

The media gateways 14 typically include one or more radio media gateways 20, for handling voice and data traffic received from and transmitted to radio communications units 22 such as handsets carried by field-based operatives, and one or more telephone media gateways 24 for receiving voice and data traffic from a public switched telephone network (PSTN) 26, for example emergency calls received from members of the public.

The operator terminals 16 are implemented by computers and are provided with a display for displaying information to an operator, a communication device such as a headset having a microphone and earpiece through which the operator can communicate with incoming callers and with field-based operatives, and input means such as a keyboard or a touch screen by means of which the operator can interact with and control the communication system 10, for example to answer incoming calls and to route voice and data traffic to field-based operatives such as emergency services personnel.

The primary media exchange 12 includes a primary media server 27 and a primary application server 28. Similarly, the secondary media exchange includes a secondary media server 29 and a secondary application server 30. The application servers 28, 30 are provided with applications that are required to handle all of the functional aspects of the communication system 10 such as session initiation protocol (SIP) control, central business logic and determining which audio media are to be mixed by the media servers 27, 29, as is described below.

For redundancy purposes, the primary application server 28 and the secondary application server 30 are substantially identical. Similarly, the primary media server 27 and the secondary media server 29 are also substantially identical. Thus, in the event of failure of the primary media server 27 or the primary application server 28 of the primary media exchange 12, the secondary media server 29 or the secondary application server 30 of the secondary media exchange 18 can be brought online for continuity of service.

The primary and secondary media servers 27, 29 are dedicated to routing communication data such as voice data from the media gateways 14 through the system 10, so as to provide a reliable and high quality communication system. The media servers 27, 29 communicate with the media gateways 14 and the operator terminals 16 using a system based on the Intemet Protocol (IP) communications standard. Voice data from the media gateways 14 takes the form of Voice Over Internet Protocol (VOIP) data packets. Using Internet Protocol for communications between the media servers 27, 29 and the media gateways 14 and the operator terminals 16 offers numerous advantages.

For example, the media servers 27, 29, the telephone media gateway 24 and the application servers 28, 30 can be constructed using commercial off the shelf components, which reduces initial procurement costs and annual maintenance costs, as no bespoke hardware is required. The use of commercial off the shelf components can also reduce the physical size and power consumption of the system 10 in comparison to existing communication systems, as physically small components with low power consumption can be employed.

This also allows for a modular architecture which can be built to an initial specification and subsequently modified, upgraded or expanded as user requirements change. For example, if increased capacity for receiving and responding to incoming telephone calls and/or radio communications is required, additional telephone media gateways 24 and radio media gateways 20 can quickly and easily be added to the system 10.

Moreover, the media gateways 14 and the operator terminals 16 can be positioned at any location where a LAN or WAN connection to the media exchanges 12, 18 is possible.

This means that a control centre manned by operators using operator terminals 16 can be remote from a secure location housing the media exchanges 12, 18.

Perhaps more importantly, two or more geographically remote systems 10 can be linked to provide a failsafe such that in the event of failure of one of the systems 10 the other system 10 can rapidly be connected to the radio media gateways 20 and operator terminals 16 of the failed system 10 to ensure continuity of service, as is described in more detail below.

Additionally, the media gateways 14 can be located close to telephone and radio network terminations, provided a WAN or LAN connection to the communication system 10 exists. For example, a radio media gateway 20 may be located at or close to an analogue radio base station or a radio system (such as TETRA) dispatcher interface point of presence to ensure that audio signals received from the radio network can be converted into IP data packets as quickly as possible after they are received at the base station or point of presence.. Moreover, the radio media gateways 20 can be located at locations which are most geographically convenient for interfacing with the radio network, thereby providing operators with flexibility in terms of the location of the radio media gateways 20, rather than constraining the operators to locating the radio media gateways 20 at the same (usually central) locations as the media exchanges 12, 28.

A key requirement of communication systems of the kind described herein is quality of service, in that it is important, particularly in systems for use by the emergency services, that the system does not drop, delay or distort calls received from the telephone network or radio communications from field based operatives.

Known ICCS architectures have dedicated channels for telephone and radio signals and thus quality of service is typically very high, since the public switched telephone network and specialist radio communications systems such as TETRA are designed specifically to carry voice signals.

In contrast, the communication system 10 uses Internet Protocol to carry all voice media and data in the system 10. Some known Internet Protocol based voice and data systems use an "IP Exchange" system for transmission of data packets carrying voice signals from, for example, a handset carried by a field-based operative to an operator control centre. Such systems connect the handset to a network of "peering points" operated by one or more operators. The peering points effectively form a chain of routers which is terminated at the operator control centre, such that a call can be set up between the handset and the operator control centre and voice data can be streamed directly between the handset and the operator control centre over the network of interconnected peering points.

In the system 10 the media servers 27, 29, act as a single central hub for all incoming and outgoing voice and data traffic. The media servers 27, 29 are configured to prioritise voice traffic and to route such traffic to the appropriate destination as quickly as possible, thereby reducing latency.

Moreover, the media servers 27, 29 are configured to maximise the efficiency with which available bandwidth is used. In known ICCS architectures all incoming voice data streams from media gateways is muhiplexed together and routed or transmitted to all operator terminals, with each operator terminal being configured to de-muhiplex the muhiplexed voice data streams to isolate a particular voice data stream of interest. Thus, in an exemplary situation where there are ten media gateways and ten operator terminals, the voice data streams received from all ten media gateways are routed to all ten of the operator terminals, and each operator terminal must de-muhiplex the received voice data streams to isolate the voice data stream of interest.

Additionally, in prior art systems voice data broadcasts may be made to the operator terminals, which again require sufficient bandwidth for the broadcast to be routed to all of the operator terminals simultaneously.

In contrast, in the system 10 the media servers 27, 29 are configured to mix incoming voice data streams from the media servers 14 and to direct a single voice data stream to a single operator terminal 16. Thus, the bandwidth required to route an incoming call to an operator is reduced in comparison to known ICCS architectures, since a single voice data stream is routed to the or each operator terminal 16, rather than routing all incoming voice data streams to all of the operator terminals 16 and isolating at a particular operator terminal 16 the single voice data stream of interest.

For voice data broadcasts, the media servers 27, 29 can be configured only to transmit or route the broadcast voice data to those operator terminals 16 which are available or willing to receive them, thereby reducing the bandwidth required for broadcast voice data. For example, where an operator terminal 16 is occupied by an ongoing call it will not be able to receive broadcast voice data. The media servers 27, 29 are aware of this, and will not attempt to route the broadcast voice data to that operator terminal 16.

Similarly, it may not be appropriate or desirable for some operator terminals 16 to receive broadcast voice data. The media servers 27, 29 can be informed of this and can be configured not to route or transmit broadcast voice data to such operator terminals, thereby reducing the bandwidth required to broadcast voice data to the appropriate operator terminals 16.

Of course, where all of the operator terminals 16 are available and able to receive broadcast voice data, the bandwidth required to broadcast the voice data may not be reduced in comparison to prior art architectures. However, in practice this may rarely be the case, since there may often be circumstances in which one or more of the operator terminals 16 is unavailable or unwilling to receive voice data broadcasts.

As is explained above, the system 10 includes a primary media exchange 12 and a secondary media exchange 18 which can be brought online to ensure continuity of service in the event of failure of the primary media exchange 12. This process will now be described in more detail, with reference to Figure 2 of the accompanying drawings.

Figure 2 is a simplified representation of a situation in which a handset 22 is in communication with the primary media server 12, as indicated by the solid arrow 40. For the purpose of clarity the interaction between the handset 22 and the radio media gateway is not illustrated in Figure 2, but it will be appreciated that data packets transmitted between the handset 22 and the primary and secondary media servers 12, 18 are routed via the radio media gateway.

The primary and secondary media servers 27, 29 are permanently switched on, but in normal operation of the system 10 only the primary media server 27 is active in routing data packets between the handset 22 and the operator terminals 16. The primary and secondary media servers 27, 29 communicate with each other and are provided with fauh diagnostic systems such that in the event of a fault with or failure of the primary media server 27 which impedes or prevents it from functioning correctly to route data packets a signal can be sent to the secondary media server 29 to bring the secondary media server 29 online to provide continuity of service to minimise any loss of data packets.

To this end, the primary and secondary media servers 27, 29 have a single "floating" IP address, which is normally allocated to the primary media server 27. In the event of a fault or failure of the primary media server 27 the secondary media server 29 adopts this IP address, such that data packets are automatically routed to the secondary media server 29 without requiring any modification or re-transmission of data packets already in transit, as is indicated by the dashed arrow 42.

The radio media gateways 20 act as interfaces between the communication system 10 and radio equipment such as TETRA handsets 22 used by field based operatives, and are configured to receive digital and/or analogue radio communications from the radio equipment and convert them to data packets which can be transmitted to the media server 12 by means of a LAN or WAN connection. Each radio media gateway 20 is provided with a number (e.g. 24) of dispatcher interface (DI) ports by means of which the radio media gateway 20 can connect to a secure radio network such as a secure TETRA network to receive radio signals from handsets 22 and other radio equipment. The DI ports of the radio media gateway 20 can be allocated dynamically by the active application server 28, 30. Thus, when an operator at an operator terminal 16 requires a DI port of the radio media gateway the active application server 28, 30 allocates a DI port of the radio media gateway 20 to that operator terminal 16, This provides flexibility, as the DI ports can be allocated to accommodate changing capacity requirements.

Each radio media gateway 20 is powered by a primary power supply unit (PSU) and cooled by a primary fan, and secondary power supply units and fans are provided in each radio media gateway 20 and can be activated in the event of failure of the primary PSU or fan to ensure that the radio media gateway 20 can continue to operate despite the failure of the primary PSU or fan.

The radio media gateway 20 converts the voice and data components of such received signals into IP data packets which are transmitted to the media server 12 for processing and onward routing. Similarly, IP data packets representing voice and data signals transmitted by the media server 12 to the radio media gateway 20 are converted by the radio media gateway 20 into appropriate radio signals for transmission to one or more handsets 22.

This "translation" between radio signals and IP data packets permits flexibility in locating the radio media gateways 20, as they can be sited at any location where there is a LAN or WAN connection to the communication system 10. This allows the radio media gateways 20 to be located at or close to radio communication terminations such as base stations, which can help to minimise degradation of radio communications, since the received radio signals are almost immediately converted into IP data packets.

Alternatively, voice over IP (VOIP) audio from a radio network such as a secure TETRA network may be translated into SIP (session initiation protocol) controlled VOIP by the radio media gateway 20.

The telephone media gateways 22 act as interfaces between the public switched telephone network (PT SN) 26 and the communication system 10, and are configured to convert the voice component of received telephone signals into IP data packets which can be transmitted to the media sewer 12 for processing and onward routing to the operator terminals 16 for example. Similarly, IP data packets representing voice signals transmitted by the media sewer 12 to a telephone media gateway 22 are converted by the telephone media gateway 22 into appropriate signals for transmission via the PSTN 26.

The telephone media gateway 22 can be upgraded or expanded to accommodate new telephony standards by upgrading firmware or software provided on telephone media gateway 22.

A typical implementation of an integrated communication control system (ICCS) employing the system 10 will now be described by reference to Figures 3 to 5 of the accompanying drawings.

Referring first to Figure 3, a typical implementation of an ICCS is shown generally at 60.

In the implementation illustrated in Figure 3, a first communication system 62 is situated at a primary data centre and a second communication system 64 is situated at a secondary data centre. The first and second communication systems 62, 64 include the elements of the communication system 10 described above, which are denoted in Figure 3 with the same reference numerals as in Figure 1.

The primary and secondary media exchanges 12, 18 of the first and second communications systems 62, 64 are connected to each other and to their respective radio and telephone media gateways 20, 22 and operator terminals 16 by a WAN or LAN network 66. The radio media gateways 20 permit connections with radio communications devices such as handsets 22, and these devices operate in a secure radio network such as a secure TETRA network.

In the implementation illustrated in Figure 3 the first and second communications systems 62, 64 each have two operator terminals 16, which are connected to their respective primary media exchanges 12. Thus, the first and second communications systems 62, 64 at the first and second data centres operate independently of one another.

However, because the first and second communication systems 62, 64 are connected by the LAN or WAN 66, the second communication system 64 provides redundancy for the first communication system 62, such that in the event of a fault, failure or unavailability of one of the components or resources of the first communication system 62, the second communication system 64 can be brought online to provide continuity of service.

Similarly, in the event of a fault, failure or unavailability of a component or resource of the second communication system 64, the first communication system 62 can be brought online to provide continuity of service.

Examples of the resilience provided by the implementation shown in Figure 3 will now be described with reference to Figures 4 and 5.

In the situation illustrated in Figure 4, the user terminal 16d is unable to connect to the primary media exchange 12 of the second communication system 64. However, because of the LAN/WLAN connection 66 the user terminal 16d is able to connect to the primary media exchange 12 of the first communication system 62 and thus can continue to be used.

In the situation illustrated in Figure 5, the primary and secondary media exchanges 12, 18 of the first communication system 62 are unavailable. Because of the LAN/WAN connection 66 however, resources of the first communication system 62, i.e. the user terminals 16a, 16b and the radio media gateways 20a, 20b, are able to connect to the primary media exchange 12 of the second communication system 64 to maintain continuity of service. It is important to note that the dynamic allocation of DI ports of the radio media gateways 20 allows the radio media gateways 20a, 20b of the first communication system 62 to switch to the second communication system 64.

From the foregoing it will be appreciated that the communication system 10 provides a flexible, resilient and expandable solution which fully integrates telephone and radio signals in a single Internet Protocol based system.

Claims

CLAIMS1. A communication system comprising a media server, a plurality of media gateways and a plurality of operator terminals, wherein: the media gateways are configured to transmit and receive signals to and from communications networks external to the communication system; the media server is configured to route data between the media gateways and the operator terminals to permit communication between the external communications networks and the operator terminals; and the data routed by the media server comprises Internet Protocol (IP) data packets.
2. A communication system according to claim 1 wherein the media server is a primary media server and further comprising a secondary media server which is operable in the event of a fault or failure of the primary media server.
3. A communication system according to claim 2 wherein the primary media server and the secondary media server are configured to communicate with each other such that on detection of a fault or failure of the primary media server the secondary media server is activated.
4. A communication system according to claim 3 wherein the primary media server and the secondary media server share a single IP address such that when the primary media server is active the IP address is assigned to the primary media server and when the secondary media server is active the IP address is assigned to the secondary media server.
5. A communication system according to any one of the preceding claims wherein the plurality of media gateways comprises a telephone media gateway.
6. A communication system according to claim 5 wherein the telephone media gateway is configured to convert signals received from a telephone network to IP data packets and to convert IP data packets received from the media server to signals for transmission to the telephone network.
7. A communication system according to any one of the preceding claims wherein the plurality of media gateways comprises a radio media gateway.
8. A communication system according to claim 7 wherein the radio media gateway is configured to convert radio signals received from a radio network to IP data packets and to convert IP data packets received from the media server to signals for transmission to the radio network.
9. A communication system according to claim 8 wherein the radio media gateway is configured to receive signals from and transmit signals to a TETRA network.
10. A communication system according to any one of the preceding claims further comprising an application server.
11. A communication system according to any one of claims 7 to 9 wherein the radio media gateway has a plurality of dispatcher interface (DI) ports for connecting the radio media gateway to the radio network.
12. A communication system according to claim 10 and claim 11 wherein the application server is configured to allocate the DI ports of the radio media gateway.
13. A communication system according to claim 10 whcrein the application server is a primary application server and further comprising a secondary application server which is operable in the event of a fault or failure of the primary application server.
14. A media server for routing data between media gateways and operator terminals in a communication system to permit communication between the external communications networks and the operator terminals, the media server being connectable to the media gateways by means of an Internet Protocol (IP) network and wherein the data routed by the media server comprises IP data packets.
15. A radio media gateway comprising means for interfacing the radio media gateway to a radio network, means for interfacing the radio media gateway to an Intemet Protocol (IP) based network and means for converting radio signals received from the radio network into data packets for transmission via the IP based network, and for converting data packets received from the IP based network into radio signals for transmission to the radio network.
16. A radio media gateway according to claim 15 wherein the means for interfacing the radio media gateway to the radio network comprises a plurality of dispatcher interface (DI) ports.
17. A radio media gateway according to claim 16 wherein the DI ports are configured for dynamic allocation by an application server of a first communication system to which the radio media gateway is connected, such that in the event that the first communication system is or becomes unavailable the radio media gateway is able to connect to a second communication system associated with the first communication system.
18. A radio media gateway according to any one of claims 15 to 17 wherein the radio network is a TETRA network.
19. A communication system substantially as hereinbefore described with reference to the accompanying drawings.
20. A media server substantially as hereinbefore described with reference to the accompanying drawings.
21. A radio media gateway substantially as hereinbefore described with reference to the accompanying drawings.