WO2005004349A2

WO2005004349A2 - Telecommunications system

Info

Publication number: WO2005004349A2
Application number: PCT/GB2004/002826
Authority: WO
Inventors: Christophe Jean Bataillard
Original assignee: Inquam (Uk) Limited
Priority date: 2003-06-30
Filing date: 2004-06-30
Publication date: 2005-01-13
Also published as: GB2403622A; GB0315309D0

Description

TELECOMMUNICATIONS SYSTEM

The present invention relates to telecommunications. Aspects of the invention relate to the provision of dispatch services by a telecommunications network.

The term "communications device" used herein preferably refers to any device used for the purpose of voice or data communication, or other kinds of communication. In preferred examples, a wireless communications device is used, that term preferably referring to devices which provide communication functions for communicating over a wireless communications network.

Examples of such communications devices include mobile or handheld devices, such as wireless or mobile telephones, wireless modems, personal digital assistants (PDAs) or other devices, for example, devices comprising a combination of features of a mobile telephone and a PDA.

Dispatch services are commonly used by the emergency services (such as the police and ambulance service) and taxi companies to allow voice communication between a central control centre and a number of remote users. In a typical dispatch service, mobile users communicate with a control centre in a fixed location via a radio-based system. A dispatcher in the control centre is able to send messages to any or all of the mobile users and the mobile users are able to respond to the dispatcher.

Other examples of dispatch services do not require all communications to be with a control centre. These examples of dispatch services allow one-to-one communication between two remote users and/or "group call" functionality in which several remote users can send and respond to messages with each other.

Dispatch services are often described as Push To Talk (PTT) communications systems since users of such communications systems typically (but not always) transmit messages to other users by pushing a button, usually located on a handset of a communications device, before speaking their message into a microphone. Users signal the end of their message by releasing this so-called Push To Talk button. The message is transmitted to other users via a communications network and is audibly reproduced by loudspeakers on these other users ' communications devices. Users may then respond to the message by pushing the Push To Talk buttons on their own communications devices in a similar fashion.

It will be understood that in the context of the present invention the terms "dispatch service", "dispatch system" and "Push To Talk" (PTT) are preferably used interchangeably to refer to voice communications via a central dispatcher, one-to-one communications and group calls. Such communications may occur in real time or may involve the storage of voice-based messages to which the recipient can listen at a later time. Preferably the term "voice communications" is to be understood to relate to communications in which information representing an audible signal (such as speech or music, for example) is transmitted and/or received by a user.

Traditional dispatch services use a radio-based communications infrastructure, which typically covers only a small geographical area. The geographical coverage of such dispatch services is limited by the ability of remote communications devices to transmit signals over long distances and by the small geographical reach of a private wireless communications network infrastructure.

Dispatch services commonly provide a means by which a service administrator can configure "groups", which are predefined sets of users who may communicate with each other via the dispatch service.

An object of the present invention is to provide a means of defining groups of users of a communications system, particularly a dispatch service.

In accordance with a first aspect of the present invention, there is provided a group- based telecommunications system for enabling communication between users in a group, the system being adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

The group-based communications system is preferably such that a first user is permitted to communicate via the telecommunications system with a second user who is a member of a group of which the first user is also a member, but the first user is not permitted to communicate via the telecommunications system with a second user who is not a member of a group of which the first user is a member. Thus, the system can control communication between users by allocating users to groups, such that each user can send and receive communications with other users for whom the communications are relevant. The rule-based aspect of the communications system can provide one or more criteria that determine the allocation of users to groups, and can thus determine which communications are relevant to each user. The telecommunications system may optionally enable other types of communication.

The dynamic behaviour of the system can improve the relevance of the communications that are sent and received by each user by providing a convenient and timely means of evaluating and re-evaluating the criteria that determine group membership. Dynamic behaviour will be discussed in more detail below.

Preferably a user may be a member of zero or more groups at any given time.

Preferably each group may comprise zero or more users (members) at any given time. In an example of a case in which a group comprises zero members, the system evaluates the rules that determine membership of that group until one or more users satisfy the criteria for group membership and the system then allocates these users to the group.

A group may also comprise all users of the telecommunications system. For example, such a group may be used to send messages that are relevant to all users, such as in an emergency for example.

Preferably the system is adapted to manage two or more groups of users.

Preferably the system maintains a record of the groups to which each user is currently assigned. This record may be stored in a database, a flat file or any other appropriate data structure. By maintaining and storing a record of the groups to which a user is currently assigned, preferably that user can see the groups to which he is assigned at any given time, for example by means of a list of that user's current groups which is displayed on a display screen of a communications device such as a mobile telephone. Thus, the user can preferably select one or more of the groups to which he is currently assigned from a list of such groups displayed on his communications device, before sending a communication to the selected group or groups. Such predetermination of each user's group membership can, in some circumstances, also be a computationally efficient manner of determining those users who ought to receive communications directed to a particular group. Alternatively, the system may re-evaluate the groups to which each user ought to be assigned whenever a communication is sent, thus obviating the need to store a record of group memberships.

Preferably the telecommunications system comprises means (such as one or more servers and/or software) for evaluating the criteria determining group membership in respect of a plurality of users. This can enable the system to determine which user (or users) of that plurality of users ought to receive a communication sent to a particular group. Preferably the means for evaluating the criteria determining group membership is integral with and/or adapted to communicate with a telecommunications network. Thus, when a communication is sent to a particular group, the members of that group (that is, the users who ought to receive that communication) are preferably determined centrally by one or more servers; the server (or servers) then enable the communication to be forwarded, via a telecommunications network, to only those users of the communications system who are members of the group in question. This arrangement can allow for efficient use of the telecommunications network, by sending a communication only to those users for whom the communication is intended.

In an alternative, but related, example, the means for evaluating the criteria determining group membership is adapted to send (periodically or on-demand) a list of the users who are members of a particular group to other users of the telecommunications system; thus, a communication that is to be sent to a particular group can be sent directly to the members of the group by the user sending that communication, rather than being forwarded to those users via a central server. This arrangement can allow a user to have advance knowledge of the other users to which a particular communication will be sent.

In a further example of an alternative system, every communication sent via the communications system is received by the communications devices of all users of the system. In this example, the communications devices (rather than a central server) evaluate the criteria determining group membership, in order to determine whether the communication is intended for the user with which that device is associated: if the communication is not intended for the user associated with that communications device, then the communication is discarded; otherwise, the communication is stored and/or reproduced (by a loudspeaker or a display screen, for example). This arrangement can require a significant amount of processing resources on the communications devices and can result in a significant amount of traffic on the telecommunications network, but can reduce the processing resources that are required to be provided centrally by the operator of the communications system. Preferably the telecommunications system comprises a dispatch system, preferably a PTT communication system.

The telecommunications system can be particularly advantageous when used in the context of a dispatch system. Communications via a dispatch system typically occur in real time: in other words, an incoming communication is typically reproduced audibly on the recipient's communications device as soon as (or shortly after) the communication is received. This can allow the recipient to respond to the communication promptly, and can thus allow a real time (or nearly real time) dialogue to be established between the parties to the communication. The dynamic allocation of users to groups can help to increase the overall relevance of communications that a user receives at a point in time, by preventing the receipt of potentially irrelevant communications from other users who do not at that point in time satisfy the criteria governing group membership; this can allow a user to concentrate upon (and to reply promptly to) those relevant communications. The benefits of improving the relevance of communications in this manner are particularly apparent when a large number of communications would otherwise be received, for example when the dispatch service comprises a large number of users, many of which are communicating at a particular point in time, and when not all of these communications are relevant to certain other users at that point in time.

Furthermore, communications devices for use with dispatch systems are typically portable, and certain communications (such as travel-related information, for example) are only relevant during the time that a user is in a particular set of circumstances. Such circumstances might include, for example, the user being in a certain location or geographical region, or the user travelling in a particular direction. These circumstances can change over time as the user travels or moves with his communications device. Thus, the dynamic allocation of users to groups can allow users to receive communications that are relevant to their circumstances at a particular point in time, and help to prevent users from receiving communications that not relevant to their circumstances at that time. The dynamic allocation of users to groups can also help to reduce unnecessary traffic on a communications network and/or unnecessary storage of communications which are relevant for only a limited duration, by enabling users to be conveniently removed from groups. For example, users may be removed from groups when the communications devices associated with those users are switched off or moved to a geographical region that is not covered by a telecommunications network, or when a user indicates that he is not currently available to receive communications.

Preferably the system comprises a telephone network.

In contrast to, for example, traditional radio-based dispatch services, which have a very limited geographical coverage, the area covered by a telephone-based dispatch service is restricted only by the geographical extent of the underlying telephone network. This allows the possibility of dispatch services with dynamic group management functionality that have global coverage.

Preferably the telephone network comprises a cellular telephone network.

Wireless telephone networks, such as cellular telephone networks, impose few restrictions on the movement of users of the dispatch service within the coverage area. The use of existing cellular telephone networks to provide dispatch services with dynamic group management functionality is particularly advantageous since it can reduce the amount of new network infrastructure that must be built in order to provide such services.

Preferably the cellular telephone network comprises a CDMA2000 telephone network. Other types of cellular telephone network, for example, Code Division Multiple Access (CDMA), Universal Mobile Telecommunications System (UMTS) or Global System for Mobile Telecommunications (GSM) networks may also be adapted to provide group-based communications within the scope of the present invention.

Other forms of wireless telephone network, including satellite-based telephone networks such as Iridium™ may also be adapted in a similar manner.

Preferably the system comprises a packet-based communications network. Preferably dispatch communications are transmitted by the cellular telecommunications network using a packet switched communications method, for example Voice over Internet Protocol (VoIP). The user may communicate with the telecommunications system by means of a packet-based communications network. Communication via the packet-based communications network may be as an alternative to, or in addition to, communication via a telephone network. Packet-switched communication methods may allow the communications infrastructure to be used more efficiently than for circuit-switched methods.

Preferably the packet-based communications network is adapted to enable wireless communication. For example, a user may connect to a communications network using a wireless communications system such as Bluetooth or IEEE 802.11 in order to participate in dispatch communications. A wireless packet-based communication system may impose few restrictions on the movement of the user within the coverage area of the system.

Preferably the system is adapted to add a user to and/or remove a user from a group of users automatically.

A preferred feature of the dynamic behaviour of the telecommunications system provides a means of automatically updating the membership of groups of associated users, without requiring human intervention. This may help to reduce the cost of running a dispatch service, by replacing human dispatchers with an automated system. This may also help to reduce the delay between a change in a criterion governing group membership and the resulting addition and/or removal of a user from a group, when compared to a dispatch service with human dispatchers. Thus, the timeliness and relevance of the communications that users send and receive may be improved.

In some examples, an administrator of the dispatch service can select one or more users who are eligible for allocation to a particular group, such that only those users who are so approved by the administrator can be assigned to that group when the criteria determining group membership are fulfilled. In other examples, the involvement of the administrator can be limited simply to creating an account for a user who has subscribed to the dispatch service, such that the user can be assigned to a group without further involvement from the administrator whenever the criteria determining group membership are fulfilled.

In further examples, users are not required to subscribe to the dispatch service. Thus, any user whose communications device is in communication with a telecommunications network can join any group for which he satisfies the criteria that determine membership. This can allow, for example, "roaming" users who are subscribers to different telecommunications networks or different dispatch services to join groups conveniently.

Preferably the system is adapted to add a user to and/or remove a user from a group of users in real time.

A preferred feature of the dynamic behaviour of the telecommunications system is the allocation of users to groups in real time, based upon the most up-to-date information available, in order to improve the timeliness and thus the relevance of the communications that users send and receive.

Real time allocation of users to groups may be achieved by re-evaluating a rule that determines the allocation of a user to the group whenever a piece of information relating to that user, or to another user, changes. For example, an interrupt-driven mechanism may be used, in which an interrupt is generated whenever a piece of information relating to a user changes and in which the interrupt causes one or more rules governing group membership to be re-evaluated.

Real time allocation of users to groups may, alternatively or additionally, be achieved by re-evaluating a rule that determines the allocation of a user to a group on a periodic basis.

Preferably the rule is re-evaluated more frequently than once per hour. More preferably, the rule is re-evaluated more frequently than once per minute. Yet more preferably, the rule is re-evaluated more frequently than once per second.

Preferably the rule is based upon the location of a user. Location-based rules allow communications between users to be controlled according to the current geographical location of each user. For example, this type of rule may assist in allowing users to send and receive relevant communications when all users within a similar geographical region (such as a town, for example) are allocated to a common group.

Such a rule may also be based upon the location of a user's communications device. For example, the location of a user may be inferred from the location of the user's communications device, particularly where the location of the communications device is determined by an automated means. In many cases, such as when the communications device is portable and is carried by the user, the location of the user may be assumed to be equivalent to the location of the user' s communications device.

Preferably the system includes means (such as a computer, a computer program and/or a PDE Cloud) for deriving information relating to the location of a user from a location determining system. The use of a location determining system can allow information relating to the location of a user, and thus the user's group memberships, to be updated whenever the location of the user (or a handset associated with that user) changes. This can allow users who are travelling to be added to and removed from groups based upon their instantaneous location.

The location determining system is preferably an automated system that requires no user interaction. In an example, the location of the user may be estimated according to the location of a Base Transceiver Station with which the user's communications device is communicating. An automated system can be convenient, particularly when there is a desire for users' locations to be determined frequently such that users can be assigned to groups according to up-to-date information relating to their location; in this situation, the time taken for users to provide their location manually might prevent the accurate or frequent provision of information. Such a system also be advantageous for allowing a user to be assigned to an appropriate group in the event that the user does not know his current location.

The telecommunications system may comprise the location determining system, or the telecommunications system may include means (such as a computer, a computer program and/or a communications network for receiving information relating to location) for obtaining location information from an external location determining system.

Preferably the location determining system is a satellite-based navigation system. , Preferably the satellite-based navigation system is the Global Positioning System (GPS).

GPS provides an accurate means of determining the location of a user. GPS is particularly convenient because many CDMA communications devices comprise GPS functionality. Such CDMA communications devices typically comprise a GPS receiver that is adapted to receive a signal from a satellite-based navigation system, thereby allowing the location of the communications device to be determined. It will be appreciated that other communications devices that do not comprise CDMA functionality may also be adapted to comprise GPS functionality, such as by the inclusion of a GPS receiver in the communications device. It will also be appreciated that the communications device may not itself comprise functionality for enabling its location to be determined by the location determining system, but may be adapted to communicate with a separate device comprising such functionality (for example a separate, and preferably self-contained, GPS receiver). Such communication with the separate device can be enabled, for example, by a wireless link (for example a Bluetooth compatible link) or a physical link (for example a cable-based connection).

The rule may be based on one or more criteria. Each of these criteria may be based upon different information relating to the user.

Preferably the rule is based upon the direction of motion of a user.

An example of a situation in which a direction-based rule may assist in allowing users to send and receive relevant communications is when users travelling in the same (or even opposite) direction along a particular section of a road are assigned to a common group, to allow the exchange of information relating to traffic and weather conditions. In a further related example, the direction-based rule may be combined with a location-based rule, which can allow communication between users travelling in the same direction on the same road, whilst not allowing communication between users travelling in the same direction on parallel roads. Such a rule may also be based upon the direction of motion of a user's communications device. For example, the direction of motion of a user may be inferred from the direction of motion of the user's communications device, particularly where the direction of motion of the communications device is determined by an automated means. In many cases, such as when the communications device is portable and is carried by the user, the direction of motion of the user may be assumed to be equivalent to the direction of motion of the user's communications device. Preferably the direction of motion is derived from two measurements or estimates of the user's location at different times. Alternatively, the direction of motion may be derived from a directional measurement taken by a compass.

Preferably the direction of motion is determined by, or derived from, an automated system that requires no user interaction.

Preferably the system includes means (such as a computer and/or a computer program) for deriving the direction of motion from two or more GPS readings. Alternatively, the direction of motion of the user may be derived from two or more estimates of location that are based upon the location of two or more Base Transceiver Stations with which the user's communications device communicates at different times.

Preferably evaluation of the rule involves determining a first time and/or date.

An example of a situation in which a time-based rule may assist in allowing users to send and receive relevant communications is when users who are shift workers are assigned to a common group at the start of their shift and removed from the group at the end of their shift, to allow the exchange of work-related information during the shift.

Preferably the first time and/or date is the current time and/or date.

Preferably the system includes means (such as a computer and/or a computer program) for comparing the first time and/or date with a second time and/or date. For example, the current time may be compared with the times at which a particular shift starts and ends, and a user is added to a group if the current time is within the duration of the shift. Preferably the second time and/or date is predefined and stored by the system. However, either or both of the first and second times and/or dates may be calculated dynamically or manipulated by an algorithm prior to the comparison. For example, the current time may be determined and then manipulated to reflect the time in a different time zone.

Preferably the rule is based upon presence information relating to a user.

"Presence information" is preferably to be understood to be information relating to the status or availability of a user (and/or a communications device associated with that user) at a particular point in time or over a period of time. "Presence" information helps to prevent users receiving communications at inconvenient or inappropriate times. Users may provide an indication of their presence to the system, and examples of presence indications include: the user is available to send and/or receive communications; the user is busy and unavailable to send and/or receive communications; the user is not within the geographical area covered by the system and is unavailable to send and receive communications; and the communications device of the user is switched off and the user is unavailable to send and receive communications. The presence information may comprise several presence indications.

In some examples, presence information relating to a particular user can be viewed by other users, thus allowing the other users to decide whether or not to initiate a communication to that particular user.

In preferred examples, the system does not send communications to users who have indicated, via their presence information, that they are unable to receive communications; this may help to reduce traffic on the telecommunications network. However, in other examples, certain communications (such as those that are determined as being urgent or are from a particular user or group of users) are sent to users who have indicated, via their presence information, that they are unable to receive communications. This may allow, in some circumstances, important messages to be received by a user irrespective of his stated availability.

A further aspect of the invention provides a group-based telecommunications system for enabling communication between users in a group, the system being adapted to add a user to and/or remove a user from a group of users, automatically and/or in real time, according to a rule.

A further aspect of the invention provides a communications device adapted to communicate with a communications system as described herein.

Preferably the communications device comprises one or more of: a mobile telephone; a modem; and a personal digital assistant (PDA).

A further aspect of the present invention provides a method of dynamically adding a user to and/or removing a user from a group of users in a group-based telecommunications system as described herein. A further aspect of the present invention provides a method of managing group-based telecommunications for enabling communication between users in a group, wherein a user is dynamically added to and/or a user is removed from a group of users according to a rule.

Preferably the group-based telecommunications system comprises a telephone network.

Preferably the telephone network comprises a cellular telephone network.

Preferably the system comprises a packet-based communications network.

Preferably the packet-based communications network comprises a means of wireless communication.

Preferably the user is automatically added to and/or removed from the group of users. Preferably the user is added to and/or removed from the group of users in real time.

Preferably the rule is based upon the location of a user. Preferably the location of the user is derived from a location determining system.

Preferably the location determining system is a satellite-based navigation system.

Preferably the satellite-based navigation system is the Global Positioning System (GPS).

Preferably the rule is based upon the direction of motion of a user.

Preferably the direction of motion of a user is derived from two or more measurements or estimates of a user's location. Preferably the two or more measurements or estimates of a user's location are derived from a satellite-based navigation system.

Preferably the direction of motion is derived from two or more GPS readings.

Preferably the first time and/or date is compared with a second time and/or date.

Preferably the rule is based upon presence information relating to a user.

A further aspect of the invention provides a group-based telecommunications system for enabling communication between users in a group, wherein the system includes means (such as a computer, a computer program, a location determining apparatus and/or a PDE Cloud) for determining information relating to the location and/or direction of motion of a user and means (such as a computer and/or a computer program)for allocating that user to a group of users of the telecommunications system according to the determined location and/or direction of motion of that user.

Preferably a location determining system for determining the location of the user is a satellite-based navigation system. Preferably the satellite-based navigation system is the Global Positioning System (GPS).

Preferably the system includes means (such as a computer, a computer program, a location determining apparatus, a direction determining apparatus and/or a PDE Cloud) for determining the direction of motion of the user from two or more measurements or estimates of a user's location. Preferably the two or more measurements or estimates of a user's location are derived from a satellite-based navigation system.

Preferably the system includes means (such as a computer, a computer program and/or a communications network for receiving information relating to position and/or direction) for determining the direction of motion of the user from two or more GPS readings.

A further aspect of the invention provides a group-based telecommunications system for enabling communication between users in a group, wherein the system includes means (such as a computer, a computer program, a clock, a timer, a database and/or a communications network for receiving information relating to time) for determining a first time and/or date and means (such as a computer and/or a computer program) for allocating a user to a group of users of the telecommunications system according to the first time and/or date.

Preferably the system includes means (such as a computer, a computer program, a clock, a timer, a database and/or a communications network for receiving information relating to time) for comparing the first time and/or date with a second time and/or date.

Preferably the telecommunications system comprises a dispatch system.

A further aspect of the invention provides a group-based telecommunications system for enabling communication between users in a group, wherein the telecommunications system comprises a dispatch system and includes means (such as a computer, a computer program and/or a communications network for receiving presence information) for determining presence information relating to a user and means (such as a computer and/or a computer program) for allocating a user to a group of users of the telecommunications system according to the presence information.

Preferably the system includes means (such as a computer, a computer program and/or a communications network) for permitting a first user to communicate via the telecommunications system with a second user who is a member of the group of which the first user is also a member. Thus, preferably the first user can send communications to and/or receive communications from the second user. Preferably the system includes means (such as a computer and/or a computer program) for preventing a first user from communicating via the telecommunications system with a second user who is not a member of a group of which the first user is a member. Thus, preferably the first user can neither send communications to nor receive communications from the second user.

In an alternative example, preferably a first user is permitted to send communications to a second user, but is prevented from receiving communications from the second user, if the first and second members are not both members of the same group. A further aspect of the invention provides a method of managing group-based telecommunications for enabling communication between users in a group, comprising the steps of determining information relating to the location and/or direction of motion of a user and allocating that user to a group of users of a telecommunications system according to the determined location and/or direction of that user.

Preferably a location determining system for determining the location of the user is a satellite-based navigation system.

Preferably the method further includes the step of determining the direction of motion of the user from two or more measurements or estimates of a user's location. Preferably the two or more measurements or estimates of a user' s location are derived from a satellite-based navigation system. Preferably the method further includes the step of determining the direction of motion of the user from two or more GPS readings.

A further aspect of the invention provides a method of managing group-based telecommunications for enabling communication between users in a group, comprising the steps of determining a first time and/or date and allocating a user to a group of users of a telecommunications system according to the first time and/or date. Preferably the method further includes the step of comparing the first time and/or date with a second time and/or date.

Preferably the telecommunications system comprises a dispatch system. A further aspect of the invention provides a computer program product (for example a computer program) adapted to perform a method as herein described.

The computer program product preferably comprises software which is adapted to be executed by a communications device or a component of a telecommunications network (such as a server, for example a Fleet Management Server, a Dynamic Group Application Server, a Presence Server or a Position Determining Equipment Server as herein described). The computer program product preferably comprises one or more cooperating computer program products, each of the cooperating computer program products preferably comprising software adapted to be executed by a communications device or a component of a telecommunications network.

A further aspect of the invention provides a computer program product for enabling communication between users in a group of a group-based telecommunications system, including means (such as code) for adding a user to and/or removing a user from a group of users dynamically according to a rule.

A further aspect of the invention provides a computer program product for enabling communication between users in a group of a group-based telecommunications system, including means (such as code) for determining information relating to the location of a user from a location determining system and means (such as code) for allocating that user to a group of users of the telecommunications system according to the location of that user.

A further aspect of the invention provides a computer program product for enabling communication between users in a group of a group-based telecommunications system, including means (such as code) for determining information relating to the direction of motion of a user and means (such as code) for allocating that user to a group of users of the telecommunications system according to the direction of motion of that user. A further aspect of the invention provides a computer program product for enabling communication between users in a group of a group-based telecommunications system, including means (such as code) for determining a first time and/or date and means (such as code) for allocating a user to a group of users of the telecommunications system according to the first time and/or date.

A further aspect of the invention provides a computer program product for enabling communication between users in a group of a group-based telecommunications system, the telecommunications system comprising a dispatch system, and the computer program product including means (such as code) for determining presence information relating to a user and means (such as code) for allocating a user to a group of users of the telecommunications system according to the presence information.

A further aspect of the invention provides a method of managing group-based telecommunications for enabling communications between users in a group, the method comprising the steps of determining presence information relating to a user and allocating a user to a group of users of a telecommunications system according to the presence information, wherein the telecommunications system comprises a dispatch system.

Preferably the method further comprises the step of permitting a first user to communicate via the telecommunications system with a second user who is a member of the group of which the first user is also a member.

Preferably the method further comprises the step of preventing a first user from communicating via the telecommunications system with a second user who is not a member of a group of which the first user is a member.

A further aspect of the invention provides a telecommunications system adapted to perform a method as described herein.

Preferably the system is adapted to perform the method automatically.

Preferably the system is adapted to perform the method in real time. Preferably the system comprises a dispatch service.

A further aspect of the invention provides a Dynamic Group Management System (DGMS) for use in enabling group-based communication between users of a telecommunications system, wherein the DGMS is adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

The DGMS may be an optional accessory to provide dynamic group management functionality for an existing telecommunications system. Preferably, the DGMS provides an interface through which it may interact with a component of the existing telecommunications system. Alternatively, the DGMS may be integral with a telecommunications system.

Preferably the telecommunications system comprises a dispatch service.

Preferably the DGMS is adapted to add a user to and/or remove a user from a group of users automatically.

Preferably the DGMS is adapted to add a user to and/or remove a user from a group of users in real time.

Preferably the rule is based upon the location of a user.

Preferably the DGMS comprises means (such as a computer, a computer program, a location determining apparatus, a PDE Cloud and/or a communications network for receiving information relating to location) for determining the location of a user. Preferably the rule is based upon the direction of motion of a user.

Preferably the rule is based upon the current time and/or date. Preferably the DGMS comprises means (such as a computer, a computer program and/or a database) for storing information relating to a user.

Preferably the information relating to a user is stored in a database. The DGMS may query, add, delete, modify or otherwise manipulate information relating to the user. Information relating to the user may also be stored in a flat file or any other appropriate data structure.

Preferably, the DGMS stores information relating to a plurality of users. Preferably the information relating to the user includes presence information.

Preferably a rule is based upon presence information relating to a user.

Preferably the DGMS comprises means (such as a computer, a computer program and/or a database) for storing information relating to a group.

Preferably the information relating to a user is stored in a database. The DGMS may query, add, delete, modify or otherwise manipulate information relating to the group. Information relating to the group may also be stored in a flat file or any other appropriate data structure.

Preferably the DGMS stores information relating to a plurality of groups.

Preferably the DGMS is adapted to associate information relating to a user with information relating to a group.

Thus, the DGMS can maintain a record of the groups of which each user is a member.

A further aspect of the invention provides a communications device for use in enabling group-based communication between users of a telecommunications system, wherein the device is adapted to communicate with a telecommunications system adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

Preferably the device is adapted to communicate with the telecommunications system by sending information to and/or receiving information from the telecommunications system.

Preferably the device is adapted to communicate with a dispatch service. Preferably the device is adapted to communicate with a telephone network. Preferably the telephone network is a cellular telephone network. Preferably the device is adapted to communicate with a packet-based communications network. Preferably the packet- based communications network is adapted to enable wireless communication.

Preferably the device is adapted to send a communication to the group of users. Preferably the device is adapted to receive a communication from the group of users.

Preferably the device is adapted to display a list of one or more groups.

Preferably the device is adapted to enable the selection of a group from the list of groups.

Preferably the selection of a group from the list of groups enables a communication to be sent to and/or received from the selected group.

Preferably the device is adapted to display a list of one or more users in a group.

Preferably the device is adapted to communicate information relating to the location of a user with the telecommunications system.

Preferably the information relating to the location of a user is derived from a location determining system.

Preferably the device is adapted to send information to and/or receive information from the location determining system. Preferably the location determining system is a satellite-based navigation system. Preferably the satellite-based navigation system is the Global Positioning System (GPS). Preferably the communications device is adapted to receive a GPS reading. Preferably the communications device is adapted to send a GPS reading to the telecommunications system.

Preferably the device is adapted to communicate information relating to the direction of motion of a user with the telecommunications system.

Preferably the information relating to the direction of motion of a user is derived from two or more estimates or measurements of the location of the user. Preferably the estimates or measurements of the location of the user are derived from a location determining system. Preferably the location determining system is a satellite-based navigation system. Preferably the satellite-based navigation system is the Global Positioning System (GPS). Preferably the telecommunications device is adapted to send two or more GPS readings to the telecommunications system. Preferably the device is adapted to derive the direction of motion of the user from two or more GPS readings.

Preferably the device is adapted to communicate a time and/or date with the telecommunications system. Preferably the device is adapted to communicate presence information relating to a user with the telecommunications system.

Preferably the device is adapted to enable configuration of the group.

For example, the device may preferably allow a user to create a user-defined group by allowing a user to choose one or more rules from a list of candidate rules. The device may preferably allow a user to edit information relating to a rule. For example, the device may allow a user to edit the boundaries of a geographical region that determines membership of a location-based group, or to select a direction of motion for a direction-based group.

A further aspect of the invention provides a method being substantially as herein described having reference to any of the accompanying drawings.

A further aspect of the invention provides a telecommunications system substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

A further aspect of the invention provides a communications device substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

A further aspect of the invention provides a Dynamic Group Management System substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

A further aspect of the invention provides a computer program product substantially as herein described with reference to and as illustrated in any of the accompanying drawings. A further aspect of the invention provides any feature or component being substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa.

The invention also provides a computer program and a computer program product for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein, and a computer readable medium having stored thereon a program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein.

The invention also provides a signal embodying a computer program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein, a method of transmitting such a signal, and a computer product having an operating system which supports a computer program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein.

Preferred features of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a mobile telecommunications system; Figure 2 is a flow diagram illustrating dynamic group allocation in the mobile telecommunications system shown in Figure 1; and Figure 3 is a flow diagram illustrating transmission of a message to a dynamic group in the mobile telecommunications system shown in Figure 1.

The structure of a mobile telecommunications system comprising Push To Talk (PTT) and Dynamic Group Management functionality will now be described with reference to the schematic diagram shown in Figure 1. Figure 1 relates in particular to a mobile telecommunications system based upon CDMA2000-1X. However, it will be understood that other telecommunications systems, for example CDMA2000-3X, Code Division Multiple Access (CDMA), Global System for Mobile Telecommunications (GSM) and Universal Mobile Telecommunications System (UMTS), could be adapted to provide Dynamic Group Management functionality in a similar manner. Further information on mobile telecommunications systems and CDMA2000 may be found in the book "3G Wireless Networks" by Smith, C. and Collins, D. (McGraw-Hill, 2002).

The mobile telecommunications system shown in Figure 1 comprises a communications device 2. The communications device 2 typically comprises electronic components (not shown) including: an antenna; a modulator; a demodulator; an amplifier; a central processing unit, such as a microprocessor or microcontroller, programmed with appropriate software; memory; and a power source, such as a battery. These electronic components cooperate to allow the mobile telephone to transmit and receive data (including data representing voice communications) with a telecommunications network in a known way.

The telecommunications network comprises several Base Transceiver Stations 4. Each Base Transceiver Station (BTS) 4 comprises a means for transmitting and receiving data with the communications device 2 through a wireless communications channel 3. Each BTS 4 communicates with those communications devices 2 that are located within a finite geographical area proximal to the BTS 4, known as a cell. The size of the geographical area covered by a cell is dependent upon factors including the power of the transmitters of both the BTS 4 and the communications device 2 and geographical features. A number of suitably located BTSs 4 are provided such that the whole of a geographical area of interest (or a significant part thereof) is covered by cells. The communications device 2 communicates with only one BTS 4 at any given time; this is typically the most proximal BTS and is thus the BTS with which the communications device can send and receive a communications signal of greatest power. It is possible that the communications device 2 will move between several cells if it moves within the geographical area covered by the telecommunications network. To attempt to ensure that the communications device 2 maintains an adequate communications link with the telecommunications network, the communications device will cease communicating with the BTS 4 located within the original cell and will commence communicating with the BTS of the new cell. For example, if a communications device 2 that originally communicates with the BTS denoted by the reference numeral 4b moves to a different geographical location, and hence moves to a different cell, the communications device will communicate with a different BTS such as that denoted by the reference numeral 4c.

A Base Station Controller (BSC) 6 manages the functions of several BTSs 4 and supervises the assignment of different BTSs to a communications device 2 that is moving between cells. A telecommunications network can comprise several BSCs 6, each of which manages several BTSs 4. A Mobile Switching Centre (MSC) 8 manages the functions of one or more BSCs 6. The MSC 8 also handles the initiation and termination of telephone calls within the mobile telephone network and to external Public Switched Telephone Networks (PSTN) (not shown).

The MSC 8 communicates with a Home Location Register/ Authentication Centre (HLR/AC) 10. The Home Location Register (HLR) is a database which stores and manages information pertaining to users of the mobile telecommunications system. Information stored by the HLR includes the present location of the communications device 2 (to assist with routing telephone calls to the communications device via the appropriate BTS 4) and details of the capabilities of the communications device 2. The Authentication Centre (AC) verifies the identity of the communications device 2. In some examples, the HLR comprises the AC as illustrated by the HLR/AC 10 functional block in Figure 1. The MSC 8 and HLR/AC 10 are particularly relevant to circuit switched telecommunications, such as voice communications, as opposed to packet switched telecommunications, such as data communications.

The BSC 6 also communicates with a Packet Control Function (PCF) 12. In some examples, the BSC 6 comprises the PCF 12. The PCF 12 provides a gateway for data communications between the communications device 2 (via the BTS 4) and those functional blocks of the network that handle packet switched communications.

The PCF 12 communicates with a Packet Data Serving Node (PDSN) 14, which routes data packets, manages Point-to-Point Protocol (PPP) sessions for data communications and manages communications between the communications device and an Authentication, Authorisation and Accounting (AAA) server 16. The functions of the AAA server 16 include authentication of the communications device during the initiation of PPP sessions. The PDSN 14 also communicates with a Home Agent (HA) 18, which tracks the location of the communications device 2 to ensure that data packets are routed correctly.

The components of the mobile telecommunications network that support dispatch services are contained within the PTT Core Network Application Cloud 19. The PTT Cloud 19 comprises four servers: an Application Server 20, a PTT Server 22, a Database Server 24 and a Registration/Location Server 26. The Application Server 20 communicates with the HA 18, the PTT Server 22, the Database Server 24 and the Registration/Location Server 26. The PTT Server 22 communicates with the HA 18, the Application Server 20 and the Database Server 24. The Database Server 24 communicates with the PTT Server 22 and the Application Server 20. The Registration/Location Server 26 communicates with the Application Server 20. In a particular example, the PTT Server 22 is a Qualcomm QChat™. In another example, the PTT Server 22 is a Winphoria Networks Global Instant Rendezvous (GIR™) server. It will be appreciated that, although the PTT Cloud 19 comprises four servers 20, 22, 24, 26 in this example, the functionality of the PTT Cloud 19 could be implemented in fewer than four servers (for example, in a single server) or in more than four servers in other examples. In a particular example, the PTT Cloud 19 uses Session Initiation Protocol (SIP) to enable VoIP communications.

The functional blocks of the communications device 2, the BTSs 4, the BSC 6, the MSC 8, the HLR/AC 10, the PCF 12, the PDSΝ 14, the AAA server 16 and the HA

18 all represent typical components of a basic CDMA2000-1X communications system. The functional blocks of the Application Server 20, the PTT Server 22, the Database Server 24 and the Registration/Location Server 26 all represent typical components used to provide dispatch service/PTT functionality in a CDMA2000-1X communications system. The remaining functional blocks shown in Figure 1 represent components that provide Dynamic Group Management functionality.

The Dynamic Group Management System (DGMS) 31 comprises a Fleet Management Server (FMS) 30, a Dynamic Group Application Server (DGAS) 32, a Presence Server 34 and a Position Determining Equipment (PDE) Cloud 36. The purpose of the DGMS 31 is to assign users to one or more groups of associated users according to one or more rules. Once assigned to a group, a user is able to send and receive communications to and from other group members, whilst those users of the telecommunications system who are not members of the group are excluded from such communications. Thus, the provision of groups allows communications between users of the telecommunications system to be controlled. Dynamic group management allows users to exchange communications with other users for whom the communications are relevant, by regularly updating group memberships according to a set of rules that relate to the relevance of these communications. It will be appreciated that, although the DGMS 31 comprises four servers 30, 32, 34 and 38 (as part of the PDE Cloud 36) in this example, the functionality of the DGMS 31 could be implemented in fewer than four servers (for example, in a single server) or in more than four servers in other examples.

The FMS 30 communicates with the Registration/Location Server 26 and the DGAS

32 to link the DGMS 31 and the communications network, particularly those parts of the network that provide PTT functionality. The FMS 30 comprises a database which stores information including a record of users of the communications system, a record of groups managed by the communications system and a record of the groups to which each user is allocated. The FMS 30 also comprises an interface through which the DGAS 32 can query the FMS database and manipulate the data held therein.

The DGAS 32 communicates with the FMS 30, the Presence Server 34 and the PDE

Cloud 36, to control and coordinate the dynamic management of groups for the dispatch service. The DGAS 32 manages groups dynamically by manipulating records within the database of the FMS 30 according to data received from the Presence Server 34, the PDE Cloud 36 or some other source of applicable data.

The Presence Server 34 communicates with the DGAS 32 and maintains a record of information relating to the "presence" of users. Presence information generally relates to whether or not a user is available to accept communications from other users. Presence information may, for example, include an indication that a user is available to accept incoming communications or an indication that a user is unavailable to accept communications due to the user being busy, located outside the geographical region covered by the telecommunications network or because the user's communications device 2 is switched off. A user can inform the Presence Server 34 of their presence by, for example, a specialised button on the communications device 2, an option selected from a menu on the communications device 2 or by an SMS message sent to the DGMS 31. A user's presence information may also be updated automatically, for example when the user switches the communications device 2 on or off, or when the communications device 2 moves into an area in which it is unable to communicate with the communications network.

The PDE Cloud 36 communicates with the DGAS 32 and the PDSN 14, to provide information on the geographical location of users to the DGMS 31. The PDE Cloud 36 comprises an application server 38 to control and coordinate its functions. The PDE Cloud 36 may determine the location of a user based upon the BTS 4 with which the user's communications device 2 is currently communicating. Alternatively, the user's location may be determined more accurately by a Global Positioning System (GPS) reading, if the communications device 2 comprises a GPS device.

The DGAS 32 utilises a set of one or more rules, which are criteria that determine how users are allocated to groups. Examples of rules that may determine whether or not a user is allocated to a particular group include:

• Location Users can be allocated to one or more groups according to the users' geographical location. For example, a subset of users of the dispatch service can be assigned to the same group if they are currently located within a similar geographical region. The size and boundaries of the geographical region can be chosen freely, and may cover a whole city or state, a particular part of a city or even the premises of a company. Users may be allocated according to a "logical region" which covers two or more geographically separate locations, such as different sites belonging to the same company. The location of a user can be determined by the PDE Cloud 36.

• Direction of Motion Users who are travelling can be allocated to groups according to the direction in which they are moving. This rule is particularly useful when combined with the previous rule relating to user location, since it allows communication between users travelling in the same direction within a defined geographical area. For example, lorry drivers travelling in a common direction along the same section of a motorway can be allocated to the same group to allow the exchange of information relating to traffic and weather conditions. In another example, a user may assigned to a group of users who are travelling in the opposite direction within a defined geographical area, which may also assist with the exchange of pertinent information relating to traffic and weather conditions. The direction of motion of a user can be derived from, for example, two or more measurements of the user's location (as determined by the PDE Cloud 36) made over a period of time.

• Time Users can be allocated to or removed from groups based upon the time of day. For example, shift workers in a particular company can be assigned to the same group at the start of their shift and removed from the group at the end of the shift. Users can also be allocated to or removed from groups based upon the date. For example, workers in a particular company can be assigned to the same group on working days and removed from the group on non-working days such as weekends and public holidays. Users can be allocated to or removed from groups based upon both the date and the time of day. For example, users can be assigned to a group for the duration of an event with predetermined starting and ending times and dates.

• Presence Indication Users can provide an indication of their current status, such as whether they are available or busy. Presence information is stored by the presence server 34. For example, a user may select an option from a menu on the communications device 2 to describe their present status, and this status indication is communicated to the presence server 34 via the communications device and telecommunications network. Users can then be allocated to or removed from groups based upon this presence information. For example, users who declare themselves unavailable can be removed from all groups to which they are currently allocated.

• Group Permissions An administrator of the dispatch service can select a set of users who are eligible for allocation to a particular group. This functionality allows the formation of "private" groups, from which users who would otherwise satisfy the allocation criteria are excluded. For example, a group may comprise only users who are employees of a particular company, or who are members of a particular team within a company. In another example, a group may comprise only users who have paid for subscription to that group.

• User Preferences Users can chose whether or not to be allocated to groups based upon a predefined set of user preferences. For example, users can choose not to be assigned to certain groups for which the allocation criteria would otherwise be satisfied. The set of user preferences may be modified and maintained by the user or by an administrator of the dispatch service.

A user can be allocated to zero or more groups at any given time. The criteria that determine group allocation can be based on any combination of rules, such as those that are listed above. A user is automatically allocated to a group whenever the criteria that determine membership of that group are satisfied. Similarly, a user is automatically removed from a group whenever the criteria governing group membership are no longer satisfied.

In an alternative example, users may be persistently allocated to one or more groups throughout the time that they are using the dispatch service. However, in this example a user's ability to send and or receive communications with other users may be varied according to any of the above rules. For example, although a user may remain allocated to a group comprising other users of the dispatch service, the user may only be permitted to communicate with these other users when he is located within a particular geographical location.

In an example, the criteria that determine group membership are chosen by an administrator of the dispatch service. For example, the criteria can be chosen such that those users who share a common purpose or common circumstances (such as those users who are working on a particular shift or who are presently in a particular geographical region, for example) are added to an appropriate group. In other examples, users of the service may choose their own criteria, thus enabling the creation of groups for a particular user-defined purpose.

The DGAS 32 comprises a database which stores information including a record of each user' s preferences, a record of the rules that determine allocation to each of the groups managed by the DGAS and a record of the preferences for each group. Group preferences can include the option to restrict a particular group to communications via a central dispatcher, one-to-one communications or group calls between three or more users. Additionally, the DGAS 32 can request user presence information from the Presence Server 34 and the locations of users from the PDE Cloud 36.

In an example, the DGAS 32 periodically compares the information pertaining to each user (including that obtained from external sources such as the Presence Server 34 and PDE Cloud 36) with the rules governing membership of each group and allocates or removes users from groups accordingly. The frequency with which the database updates each user's group allocations can be varied. For example, if it is important to ensure that users are allocated to a certain group based upon the most up-to-the- minute user information, then the DGAS 32 will compare user information with the group' s rules more frequently than for a group for which the timeliness of information is of lesser importance. In an alternative example, the DGAS 32 compares user information with the rules determining group membership on an asynchronous basis. In this example, the DGAS 32 updates the list of each user's group allocations whenever a piece of information relating to that user changes.

Optionally, the DGAS 32 comprises an interface through which external systems (not shown in Figure 1) can provide additional information to the DGMS 31 that may be used as the basis for further rules to determine group allocation. Such information may include, for example, meteorological data or travel information such as traffic conditions.

Any suitably adapted communications device 2 can use the dispatch services described within the context of the present invention. Such adaptations include the execution of software on the communications device 2 to support PTT and Dynamic Group Management functionality. This software may run within a Java or Binary Runtime Environment for Wireless (BREW™) environment on the communications device, for example. The primary function of the software is to control the exchange of pertinent information with the DGMS 31 and PTT 19 subsystems, such as the location of the communications device, a presence indication and data packets, particularly data representing voice-based communications. Additional functions of the software include controlling the storage of voice-based messages when a user is unavailable and enabling the configuration of user preferences for the DGMS 31.

In a preferred example, the communications device 2 is adapted to provide a Push To Talk button, the pressing of which will initiate the transmission of a dispatch communication. The PTT button can be implemented as a dedicated button on the communications device 2, as a button on a headset for a communications device 2, or as a button on a standard communications device keypad that has been designated as a PTT button by means of suitable software. Alternatively or additionally, the transmission of dispatch communications can be initiated by selecting an option from a menu on the communications device 2.

An example of the operation of a dispatch service incorporating Dynamic Group Management functionality is illustrated in Figures 2 and 3. The process by which a user is dynamically allocated to a group will be described with reference to Figure 2. In the first step of this example, a user who is not currently allocated to any groups switches on 100 the communications device 2. The communications device 2 then notifies 102 the DGAS 32 that the user is available to join groups. This notification message is encoded in one or more packets of data which are transmitted using Internet Protocol (IP) to the DGAS 32 via the BTS 4, BSC 6, PCF 12, PDSN 14, HA 18, PTT Cloud 19 and FMS 30. The notification message may include data to authenticate the user with the DGMS 31.

The DGAS 32 executes one or more queries 104 on the FMS 30 database to retrieve user information and a list of rules determining allocation to groups managed by the DGMS 31. In this example, a group to which the user is eligible to be allocated has a location-based rule. The DGAS 32 therefore requests 106 the location of the user's communications device 2 from the PDE Cloud 36. The PDE Cloud 36 requests 108 a GPS location reading from the communications device 2 via the PDSN 14, PCF 12, BSC 6 and BTS 4. The communications device 2 returns its location to the PDE Cloud 36 via the BTS 4, BSC 6, PCF 12 and PDSN 14, and the PDE Cloud 36 forwards this location in an appropriate form to the DGAS 32. The DGAS 32 then compares 110 user information, including the location of the communications device 2, with the rules for each group and allocates 114 the user to groups accordingly. The DGAS 32 updates appropriate records within the FMS 30 database to reflect the user being allocated to groups. The FMS 30 then notifies the communications device 2 of the groups to which the user has been allocated via the PTT Cloud 19, HA 18, PDSN 14, PCF 12, BSC 6 and BTS 4. The FMS 30 may also send a list of users who are allocated to each of these groups to the communications device 2.

The previous steps 104, 106, 108 and 110 are performed on a periodic basis for each user, to ensure that the list of groups is up to date, as indicated by the arrow denoted by the reference numeral 112. During this updating process, the DGAS 32 requests the availability of each user from the Presence Server 32. The FMS 30 may also send an updated list of users who are allocated to each group to each user's communications device 2. The process by which a user sends a message to a group will now be described with reference to Figure 3. If the user is allocated to more than one group, the user selects 150 the appropriate group from a menu in the user interface of the communications device 2 or by a dedicated group-selection control, such as a rotary switch located on the communications device 2. The user may also choose to send the message to more than one group simultaneously. The user initiates 152 transmission of the message by pressing a PTT button on the communications device 2, speaks into the mouthpiece of the communications device 2, and then releases the PTT button. The message is digitised and encoded in one or more packets which are sent 154 to the DGMS 31 using standard Voice over Internet Protocol techniques. The communications device 2 also notifies the FMS 32 of the group for which the message is intended. Packets are sent to the DGMS 31 via the BTS 4, BSC 6, PCF 12, PDSN 14, HA 18 and PTT Cloud 19.

When the message has been received, the DGAS 32 queries 156 the FMS 30 database to retrieve a list of users who are currently allocated to the group for which the message is intended. The message is then forwarded 158 using VoIP techniques to each of these users by the DGMS 31, via the PTT Cloud 19, HA 18, PDSN 14 and one or more PCFs 12, BSCs 6 and BTSs 4.

The process for responding to a message is similar to that by which a message is sent, as illustrated in Figure 3. However, it is possible to omit the step in which the user selects 150 a group if the default behaviour of the communications device software is to respond to the group from which each message originates.

If a user is unable to receive a message, for example if they have set their status as "busy" via the Presence Server 34, the message may be temporarily stored on the communications device 2 to be listened to at a more convenient time. Alternatively, the DGAS 32 may store the message for later transmission if the user has set their status appropriately via the Presence Server 34.

It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

1. A group-based telecommunications system for enabling communication between users in a group, the system being adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

2. A system according to claim 1, wherein the system comprises a dispatch system.

3. A system according to claim 1 or claim 2, wherein the system comprises a telephone network.

4. A system according to claim 3, wherein the telephone network comprises a cellular telephone network.

5. A system according to any of the preceding claims, wherein the system comprises a packet-based communications network.

6. A system according to claim 5, wherein the packet-based communications network is adapted to enable wireless communication.

7. A system according to any of the preceding claims, wherein the system is adapted to add a user to and/or remove a user from a group of users automatically.

8. A system according to any of the preceding claims, wherein the system is adapted to add a user to and/or remove a user from a group of users in real time.

9. A system according any of the preceding claims, wherein the rule is based upon the location of a user.

10. A system according to claim 9, wherein the system includes means for deriving information relating to the location of a user from a location determining system.

11. A system according to claim 10, wherein the location determining system is a satellite-based navigation system.

12. A system according to claim 11 , wherein the satellite-based navigation system is the Global Positioning System (GPS).

13. A system according to any of the preceding claims, wherein the rule is based upon the direction of motion of a user.

14. A system according to claim 13, wherein the system includes means for deriving the direction of motion from two or more GPS readings.

15. A system according to any of the preceding claims, wherein evaluation of the rule involves determining a first time and/or date.

16. A system according to claim 15, wherein system includes means for comparing the first time and/or date with a second time and/or date.

17. A system according to any of the preceding claims, wherein the rule is based upon presence information relating to a user.

18. A communications device adapted to communicate with a communications system according to any of the preceding claims.

19. A device according to claim 18, wherein the device comprises one or more of: a mobile telephone; a modem; and a personal digital assistant (PDA).

20. A method of dynamically adding a user to and/or removing a user from a group of users in a group-based telecommunications system according to any of the preceding claims.

21. A method of managing group-based telecommunications for enabling communication between users in a group, wherein a user is dynamically added to and/or a user is removed from a group of users according to a rule.

22. A method according to claim 21, wherein the user is automatically added to and/or removed from the group of users.

23. A method according to claim 21 or claim 22, wherein the user is added to and/or removed from the group of users in real time.

24. A method according to any of claims 21 to 23 , wherein the rule is based upon the location of a user.

25. A method according to claim 24, wherein the location of the user is derived from a location determining system.

26. A method according to any of claims 21 to 25, wherein the rule is based upon the direction of motion of a user.

27. A method according to claim 26, wherein the direction of motion is derived from two or more GPS readings.

28. A method according to any of claims 21 to 27 , wherein evaluation of the rule involves determining a first time and/or date.

29. A method according to claim 28, wherein the first time and/or date is compared with a second time and/or date.

30. A method according to any of claims 21 to 29, wherein the rule is based upon presence information relating to a user.

31. A group-based telecommunications system for enabling communication between users in a group, wherein the system includes means for determining information relating to the location of a user from a location determining system and means for allocating that user to a group of users of the telecommunications system according to the location of that user.

32. A group-based telecommunications system for enabling communication between users in a group, wherein the system includes means for determining information relating to the direction of motion of a user and means for allocating that user to a group of users of the telecommunications system according to the direction of motion of that user.

33. A system according to claim 32, wherein the system includes means for determining the direction of motion of the user from two or more GPS readings.

34. A group-based telecommunications system for enabling communication between users in a group, wherein the system includes means for determining a first time and/or date and means for allocating a user to a group of users of the telecommunications system according to the first time and/or date.

35. A system according to claim 34, wherein the system includes means for comparing the first time and/or date with a second time and/or date.

36. A system according to any of claims 31 to 35, wherein the telecommunications system comprises a dispatch system.

37. A group-based telecommunications system for enabling communication between users in a group, wherein the telecommunications system comprises a dispatch system and includes means for determining presence information relating to a user and means for allocating a user to a group of users of the telecommunications system according to the presence information.

38. A system according to any of claims 31 to 37, wherein the system includes means for permitting a first user to communicate via the telecommunications system with a second user who is a member of the group of which the first user is also a member.

39. A system according to any of claims 31 to 38, wherein the system includes means for preventing a first user from communicating via the telecommunications system with a second user who is not a member of a group of which the first user is a member.

40. A communications device adapted to communicate with a telecommunications system according to any of claims 31 to 39.

41. A method of managing group-based telecommunications for enabling communication between users in a group, comprising the steps of determining information relating to the location of a user from a location determining system and allocating that user to a group of users of a telecommunications system according to the location of that user.

42. A method of managing group-based telecommunications for enabling communication between users in a group, comprising the steps of determining information relating to the direction of motion of a user and allocating that user to a group of users of a telecommunications system according to the direction of motion of that user.

43. A method according to claim 42, further including the step of determining the direction of motion of the user from two or more GPS readings.

44. A method of managing group-based telecommunications for enabling communication between users in a group, comprising the steps of determining a first time and/or date and allocating a user to a group of users of a telecommunications system according to the first time and/or date.

45. A method according to claim 44, further including the step of comparing the first time and/or date with a second time and/or date.

46. A method according to any of claims 41 to 45, wherein the telecommunications system comprises a dispatch system.

47. A method of managing group-based telecommunications for enabling communication between users in a group, the method comprising the steps of determining presence information relating to a user and allocating a user to a group of users of a telecommunications system according to the presence information, wherein the telecommunications system comprises a dispatch system.

48. . method according to any of claims 41 to 47, further comprising the step of permitting a first user to communicate via the telecommunications system with a second user who is a member of the group of which the first user is also a member.

49. A method according to any of claims 41 to 48, further comprising the step of preventing a first user from communicating via the telecommunications system with a second user who is not a member of a group of which the first user is a member.

50. A telecommunications system adapted to perform a method according to any of claims 20 to 30 or 41 to 49.

51. A system according to claim 50, wherein the system is adapted to perform the method automatically.

52. A system according to claim 50 or claim 51 , wherein the system is adapted to perform the method in real time.

53. A computer program product adapted to perform a method according to any of claims 20 to 30 or 41 to 49.

54. A computer program product for enabling communication between users in a group of a group-based telecommunications system, including means for adding a user to and/or removing a user from a group of users dynamically according to a rule.

55. A computer program product for enabling communication between users in a group of a group-based telecommunications system, including means for determining information relating to the location of a user from a location determining system and means for allocating that user to a group of users of the telecommunications system according to the location of that user.

56. A computer program product for enabling communication between users in a group of a group-based telecommunications system, including means for determining information relating to the direction of motion of a user and means for allocating that user to a group of users of the telecommunications system according to the direction of motion of that user.

57. A computer program product for enabling communication between users in a group of a group-based telecommunications system, including means for determining a first time and/or date and means for allocating a user to a group of users of the telecommunications system according to the first time and/or date.

58. A computer program product for enabling communication between users in a group of a group-based telecommunications system, the telecommunications system comprising a dispatch system, and the computer program product including means for determining presence information relating to a user and means for allocating a user to a group of users of the telecommunications system according to the presence information.

59. A computer readable medium having stored thereon a computer program product according to any of claims 53 to 58.

60. A signal tangibly embodying a computer program product according to any of claims 53 to 58.

61. A method of transmitting a signal according to claim 60.

62. A Dynamic Group Management System (DGMS) for use in enabling group- based communication between users of a telecommunications system, wherein the DGMS is adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

63. A DGMS according to claim 62, wherein the DGMS is adapted to add a user to and/or remove a user from a group of users automatically.

64. A DGMS according to claim 62 or claim 63, wherein the DGMS is adapted to add a user to and/or remove a user from a group of users in real time.

65. A DGMS according to any of claims 62 to 64, wherein the DGMS comprises means for determining the location of a user.

66. A DGMS according to any of claims 62 to 65, wherein the DGMS comprises means for storing information relating to a user.

67. A DGMS according to claim 66, wherein the information relating to the user includes presence information.

68. A DGMS according to any of claims 62 to 67, wherein the DGMS comprises means for storing information relating to a group.

69. A DGMS according to any of claims 62 to 68, wherein the DGMS is adapted to associate infoimation relating to a user with information relating to a group.

70. A communications device for use in enabling group-based communication between users of a telecommunications system, wherein the device is adapted to communicate with a telecommunications system adapted to add a user to and/or remove a user from a group of users dynamically according to a rule.

71. A communications device according to claim 70, wherein the device is adapted to display a list of one or more groups.

72. A communications device according to claim 70 or claim 71, wherein the device is adapted to enable the selection of a group from the list of groups.

73. A communications device according to any of claims 70 to 72, wherein the device is adapted to display a list of one or more users in a group.

74. A communications device according to any of claims 70 to 73, wherein the device is adapted to communicate information relating to the location of a user with the telecommunications system.

75. A communications device according to claim 74, wherein the information relating to the location of a user is derived from a location determining system.

76. A communications device according to any of claims 70 to 75, wherein the device is adapted to communicate information relating to the direction of motion of a user with the telecommunications system.

77. A communications device according to any of claims 70 to 76, wherein the device is adapted to communicate presence information relating to a user with the telecommunications system.

78. A communications device according to any of claims 70 to 77, wherein the device is adapted to enable configuration of the group.

79. A method being substantially as herein described having reference to any of the accompanying drawings.

80. A telecommunications system substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

81. A communications device substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

82. A dynamic group management system substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

83. A computer program product substantially as herein described with reference to and as illustrated in any of the accompanying drawings.

84. Any feature or component being substantially as herein described with reference to and as illustrated in any of the accompanying drawings.