GB2428165A - User terminal, infrastructure processor, system and method for use in mobile communications - Google Patents

Abstract

A user terminal (109) for use in a mobile communication system (100) which includes a processor (102, 311, 312) operable to monitor data intended to be sent via a communication resource (PDCH) of the system to another terminal (119) and to detect whether the intended data transmission conforms with one or more pre-defined rules defining well behaved data transmission and, if the violation of one or more of the rules is detected, to initiate a procedure to determine if the data transmission is allowed to proceed. The procedure may include producing an alert signal for sending to a processor (112) of an infrastructure (101) of the system. A processor (112) for use in an infrastructure (101) of the mobile communication system (100) is operable to receive an alert signal from the user terminal (109), to determine whether or not the intended data transmission is allowed to proceed and to issue a response signal for sending back to the user terminal indicating a result of the determination.

Description

TITLE: USER TERMINAL, INFRASTRUCTURE PROCESSOR, SYSTEM ND METHOD FOR USE

IN MOBILE COIi.24UNICATIONS

FIELD OF THE INVENTION

The present invention relates to a user terminal, an infrastructure processor, a system and a method for use in mobile communications. In particular, the invention relates to control of data transmission in a wireless communication system.

BACKGROUND OF THE INVENTION

Mobile wireless communication systems, for example cellular telephony or private mobile radio communication systems, typically provide for radio telecommunication links to be arranged between a plurality of user or subscriber terminals, often termed mobile stations', MS5', via a system infrastructure including fixed installations including one or more base transceiver stations (BTS5) . Methods for communicating information simultaneously in such systems exist wherein communication resources are shared by a number of users.

Such methods are termed multiple access' techniques. A number of multiple access techniques exist, whereby a finite communication resource is divided into a number of physical parameters.

An example of a mobile wireless communication system is a TETRA (TErrestrial Trunked Radio) system, which is a system operating according to TETRA standards or protocols as defined by the European Telecommunications Standards Institute (ETSI) . A primary focus for a TETRA system is use by the emergency services, as TETRA systems provide efficient dispatch and control services. The system infrastructure in a TETRA system is generally referred to as a switching and management infrastructure (SwMI) . Systems operating according to other protocols are also known.

A communication system may provide radio communications between the infrastructure and MSs (or between MSs via the infrastructure) of information in any of the known forms in which such communications are possible. In particular, communicated information may represent speech or data information or control signalling messages. Data information includes digital information representing written words, numbers etc, i.e. the type of user information processed in a personal computer. In addition, data information may comprise picture or video information. Control signalling messages relate to the communication system itself, e. g. to control the manner in which MSs are served by the system in compliance with a selected protocol such as a selected industry protocol such as TETRA. Different channels may be used for communication of the different forms of information. In particular, control channels are used for transmission of control signalling messages and packet data channels, PDCH, are used to provide packet data services, PDS, in which packet data information is sent to or from MSs.

In TETRA systems and in some other trunked or cellular systems, when a user needs to make a new request to access a particular resource of the system, for example to access a particular channel, e.g. a PDCH, this request is made using a method known as a random access' procedure. In this procedure, the user's MS sends a request message on a control channel to a processor of the infrastructure, known as the BRC or Base Radio Controller', indicating the resource required, e.g. capacity in a particular communication channel such as a PDCH, to which access is required. The request may be successful or unsuccessful depending on whether or not it is chosen by the random access procedure. If it is successful, the BRC may grant the request in whole or in part by reserving all or some of the capacity requested and the requesting mobile station makes a transmission of the data in the allocated resource made available to it.

The data channels employed in a communication system can become congested with data traffic and this congestion can become serious in mission critical systems for example systems used by emergency services such as police and firefighters. Such congestion can arise in several ways such as in the following situations: (i) data applications are running in mobile stations or other user terminals that, although properly designed, generate more data traffic than was originally contemplated or was agreed with the system operator; or (ii) data applications are running in mobile stations or other user terminals that are poorly designed and consume much more system resources than are necessary; or (iii) a data application is running which contains a virus or other reproducible defect which maliciously floods the data channels to deny service to legitimate users; (iv) more users are sending data than is normal in a given site or cell, e.g. where an incident has caused many police officers with active mobile stations to converge on a particular location; (v) a deliberate denial of service has been caused by an activity of an unfriendly third party.

In present systems it is difficult or impossible for a network operator to identify the origin or cause of a congestion problem. Thus, where the problem is caused by an application running which causes malicious flooding of the data channels it will be difficult to remedy the situation by identifying and eliminating the cause of the flooding.

SUMMARY OF THE INVENTION

According to the present invention in a first aspect there is provided a user terminal as defined in claim 1 of the accompanying claims.

According to the present invention in a second aspect there is provided a processor for use in a system infrastructure, the processor being as defined in claim 23 of the accompanying claims.

According to the present invention in a third aspect there is provided a mobile communication system as defined in claim 26 of the accompanying claims According to the present invention in a fourth aspect there is provided a method of operation in a mobile communication system, the method being as defined in claim 27 of the accompanying claims.

Further features of the invention are as defined in the accompanying dependent claims and are disclosed in the embodiments of the invention to be described.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a layout of a mobile communication system.

FIG. 2 is a block schematic diagram of a mobile station included in the mobile communication system of FIG. 1.

FIG. 3 is a block schematic diagram showing the mobile station of FIG. 2 connected to a local area network and showing more detail of a processor included in the mobile station.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows a communication network system 100 operating in accordance with an embodiment of the invention. In the following description it is assumed that the system 100 is a TETRA system although it could alternatively be a system operating according to another protocol such as an internet compatible wireless protocol, e.g. GPRS (General Packet Radio Service) or UMTS (Universal Mobile Telecommunications System) . The system 100 includes a network infrastructure 101. The network infrastructure 101 includes as known main components (together with other components) (1) a BTS (base transceiver station) 103 which includes one or more transceivers providing radio communication with mobile stations within range of the BTS 103; (ii) a data gateway 104 for routing communications into and out of a fixed application data host 105 connected to the fixed network infrastructure 101; (iii) an authentication processor 106, which carries out authentication functions of the network infrastructure 101; and a memory 107 which stores data and programs needed in operation by processors of the network infrastructure 101. The network infrastructure 101 also includes, within the BTS 103, a resource allocation processor 108, e.g. a Base Radio Controller, which controls allocation of communication resources available to mobile stations served by the network infrastructure 101 and a behaviour manager 112 operating in a manner described in more detail later. The fixed application data host 105 may for example be a database, e.g. a vehicle database for use by the police.

The system 100 also includes a plurality of MSs (mobile stations) served by the network infrastructure 101, particularly by the BTS 103, three of which, MS5 109, 110 and 111, are shown.

Where an MS, e.g. the MS 109, served by the network infrastructure 101 requires to send a packet data communication from a data application running in the MS or in a device locally connected to the MS, the MS initially requests (i.e. over the air interface) packet data services and is thereby connected via the BTS 103 to the resource allocation processor 108. A request is made by the MS, by the random access procedure described earlier, for resource allocation. The request includes an indication of the size (number of bytes) of the data package to be sent. For example, in some particular implementations the request is sent in a resource request data message (PDU' message) in which there is a field indicating how many slots in a timing structure of the protocol are required. The layer 2 addressing software of the MS automatically calculates this size.

If the request is successful, the MS is granted channel resource, e.g. a number of specified slots or multislots, in which to send the data either in a single data package transmission or in two or more transmissions at different times by breaking up a large package into smaller packages. This is notified to the requesting MS by the resource allocation processor 108.

Each MS intending to make a data transmission also operates a procedure to monitor data intended to be transmitted and to detect whether the intended data transmission conforms with or violates one or more pre- defined rules defining well behaved data transmission.

Where such a rule violation is detected the MS may send an alert signal to the behaviour manager 112. The behaviour manager 112 monitors for any such alert signals from the MSs served by the infrastructure 101.

This monitoring procedure by each MS, and the receipt of the alert signal and action taken in response by the behaviour manager 112, is described in more detail later with reference to FIG. 3.

Each of the MSs 109 - 111 shown in FIG. 1 may be a portable device such as a portable radio, a mobile telephone or a wireless enabled computer. Alternatively, each of these MSs may be a radio communication unit fitted in a vehicle. FIG. 2 is a block schematic diagram showing more detail of one form of the MS 109. The MSs and 111 are constructed and operate in a similar manner. The main operations of the MS 109 are controlled by a controller 201 which operates in conjunction with a timer 209 which synchronises operations within the MS 109 and a memory 210 which stores data and programs used within the MS 109. A processor 202 processes information included in RF signals sent and received by a transceiver 203. The processor 202 extracts information from a received RF signal detected by the transceiver 203 and passes the information to an appropriate output transducer. Similarly, the processor 202 receives input information for transmission from an appropriate input transducer and delivers the information to the transceiver 203 for transmission in the form of an RF signal by the transceiver 203. As in a conventional mobile radio terminal, the MS 109 includes (as an optional component) an output transducer which is an audio output 204, e.g. a speaker, which converts signals received which represent speech information to an output audible form for delivery to a user. The MS 109 also includes (as an optional component) an input transducer which is an audio input 205 which converts an input audio signal, e.g. in the form of speech, into an electrical form in a well known manner. The electrical signal is delivered to the processor 202 described above.

A data connector 213 provides an output for data received in an RF signal at the transceiver 203 and delivered from the processor 202. The data connector 213 also provides an input for delivery of data to the processor 202 for sending as an RF transmission by the transceiver 203. The data connector 213 may comprise a connection to one or more peripheral devices, e.g. it may comprise a USB data connection. A keypad 212 serves as a user interface and allows a user to enter control signals for delivery to the controller 201 to operate functions of the MS 109. The keypad 212 also acts as another input transducer allowing entry of alphanumeric data for delivery to the processor 202 for processing to send in radio communications by the transceiver 203. A display 207 operated by a display driver 206 under control of the controller 201 provides displayed information to a user of the MS 109 in a known manner. A GPS (Global Positioning System) receiver 208 receives RF signals from GPS satellite transmitters and passes the signals to the processor 208 which is able to estimate a current location of the MS 109 using the signals in a known manner. A battery 211 provides electrical power to all operational components of the radio 125.

The transceiver 203 provides RF communications to and from the system infrastructure 101 via the BTS 103 and to and from other MS5 via the BTS 103 in a known manner.

FIG. 3 is a block schematic diagram showing how various procedures are applied in a processor of the MS 109 to control data flow in the MS 109 in accordance with an embodiment of the invention. These procedures may be applied in the processor 202, the controller 201 or a combination of the two working together or even in an associated external device which essentially becomes a functional component of the MS 109 when connected to the MS 109. In the following description it is assumed for illustration purposes that the procedures are applied in the processor 202.

Data inputs are applied to the processor 202 from the data connector 213. The data connector 213 is connected to an external computer hosting a data application. This external computer could be connected directly to the MS 109 or via a LAN (local area network) . The latter option is illustrated in FIG. 3 in which the data connector 213 is shown connected to a LAN 301 which includes a router 303 which routes flow of data within and into and out of the LAN 301. The LAN 301 may for example be a LAN in a vehicle carrying the MS 109. The router 303 has connections to various devices of the LAN 301, two of which, a video camera 305 and computer 306 including an e-mail processor 307, are shown. The links of the devices of the LAN 301 to the router 303 and from the router 303 to the data connector 213 may for example be by a wired or short range wireless connection of a known kind.

In the processor 202, data received from the external computer data application (either directly connected or indirectly connected via the LAN 301) via the data connector 213 is applied firstly to a packet classifier 309 which determines how the received data has to be classified into data packets. The result will be different for different types of data, e.g. video data and text data, e.g. in an e-mail message. The packet classifier 309 has a plurality of outputs depending on the type of data detected. Data of a first type, video data, is applied to a first shaping filter 311, Data of a second type, text data, is applied to a second shaping filter 313. The first and second shaping filters 311 and 313 operate in a manner described later.

Data is forwarded from the appropriate shaping filter 311 or 313 to a packet scheduler 315 which carries out several functions. The packet scheduler 315 stores the package of data (using the memory 210) received from the appropriate shaping filter, determines the size of the package, makes one or more requests (via the random access procedure described earlier) for data channel resource, and, when a resource is made available by the resource allocation processor 108 of the network infrastructure 101, allows the data to be forwarded for delivery to a target terminal, e.g. identified by a network address in a signal in which the data is to be sent. As noted earlier, the processor 202 prepares a signal for transmission and this is sent over the air by the RF transceiver 203. The target terminal may for example be the fixed application data host 105 connected to the network infrastructure 101 as shown in FIG. 1, or some other fixed or mobile terminal operating in the system 100.

Each of the shaping filter 311 and the shaping filter 313 operates a program which makes reference to a set of rules relating to the transmission of data. The rules are pre-defined rules which are retrieved from storage in the memory 210. These rules define a code of good behaviour as far as the system 100 is concerned in relation to transmission of data from MS5 within the system 100. The rules may be different in relation to the different data types received by the shaping filter 311 and the shaping filter 313 respectively. Each of the shaping filter 311 and the shaping filter 313 determines whether the data or its transmission will violate one or more of the rules that apply in the case of that filter.

Examples of rules that the shaping filter 311 and the shaping filter 313 may apply are as follows: (1) The data must be in the form of UDP packets (which do not require receipt messages) for delivery via an internet link and not for example in the form of TOP packets (which require receipt messages to be returned) (ii) The rate of data transmission to the air interface (i.e. to the transceiver 203) via the packet scheduler 315 must not exceed a pre- determineci threshold delivery rate. For example, precautions will be initiated if the data rate exceeds a pre-determined number of data packets, e.g. ten, per minute. This threshold can be different for different users on the same network, for example depending on their type of service subscription and could be ascertained from their user identity or user group etc..

(iii) The pre-determjnecj threshold data delivery rate must be in accordance with a priority that the data application has assigned to the data or has been pre- defined for a particular data application. This rule allows a higher data throughput for data traffic of a higher priority (e.g. where the data application itself has indicated the priority of each data message or package or flow of messages or packages) before an alert signal is produced that a rule is violated. This rule can differentiate between priorities for different applications running on or connected to the same MS or between different individual packets of data from the same data application running on or connected to the same MS.

(iv) The behavioural signature of a virus or other reproducible defect is present in the data and is detectable through a recognised sequence of packets; such a defect may have been present and downloaded in the incoming data; (v) Data packets are allowed through to the packet scheduler 315 only if the application from which they are sent is one of a list of allowed data applications.

This would require for example the filter 311 or 313 to be aware of the port numbers included in the UDP and TCP headers and for these port numbers to be allowed port numbers. A port number in this context is a field (i.e. a sequence of bits with a predefined set of meanings depending on their settings) in the protocol that is being used to identify the particular type of data application that originated this particular data packet.

There are, for example, a widely-known set of port numbers defined in the TCP and [JDP protocols to identify that packets are being used by, for example, FTP (File Transfer Protocol) applications.

Although the rules applied by the shaping filter 311 and the shaping filter 313 have been pre-determined, they may be re- defined dynamically by the system 100, e.g. by the behaviour manager 112. Thus, the behaviour manager 112 may send via the BTS 103 to the MS5 109, 110 and 111 signals to define the current rules or changes to the current rules. The rules might change for example if the capacity of the system 100 to transport data packages changes or if a user has entered into a new agreement with the system operator, e.g. to allow greater amounts of data to be sent by the user.

Different rules may be sent to different MSs, e.g. having users or user groups or classes which differ depending on a priority or seniority level assigned to those users, groups or classes. Such rule changes can be notified to MSs such as the MS 109 via the wireless interface at any time that is convenient to the operator of the communications network including the system 100.

There is no limit to the number of times these rules can be changed for any given MS or classes or groups of MSs.

Each MS receiving a notification of change(s) in the rules stores the change(s) in its memory 210 and applies the change(s) in the filters 311 and 313 the next time an intended data transmission is monitored by each of the filters 311 and 313.

Where the filter 311 or the filter 313 of the MS 109 detects that a rule violation has occurred or will occur if the transmission proceeds it generates an alert signal. Alternatively, or in addition the filter 311 or the filter 313 may carry out a determination as to whether special conditions apply to allow the data transmission to proceed despite the rule violation.

The alert signal generated by the filter 311 or filter 313 may indicate one or more of the following: (I) what rule or rules are or will be violated; (ii) an extent or details of violation; (iii) an identity of the MS 109 and/or its user and/or a class or group of users to which the user belongs; (iv) an estimate of the current location of the MS 109; (v) the current time; (vi) an ID (identity) of the site (cell) currently serving the MS; (viii) an ID of a data application running from which the data has been delivered; (ix) the type of data service (e.g. Short Data Service, Packet Data service) The alert signal is sent via the transceiver 203 as a radio signal over the air to the BTS 103 and is passed by the BTS 103 to the behaviour manager 112. It may also be passed to a network control terminal 114 for the attention of a network control manager as explained later.

The behaviour manager 112 of the infrastructure 101 is preferably a processor programmed to make an intelligent determination, upon receipt of the alert signal, as to whether or not the proposed transmission of data by the MS sending the alert signal (or pattern of behaviour of the data application run on or locally connected to that MS) may continue. For example, the violation may be overlooked if the identity of the sending MS 109 or its user or user class or group or the location of the MS 109 or other known information relating to the mission or use of the MS 109 indicates that the transmission by the MS 109 has to be given a high or special priority or permission which overrides the rule violation. Where the transmission is allowed to proceed with a rule violation, the behaviour manager 112 may require one or more conditions to be applied. For example, if the rule violated is that the maximum data packet rate per MS is not to exceed ten per minute (as mentioned in the earlier example of shaping filter rules), the transmission may be allowed to proceed but with a maximum data packet rate of say twelve per minute.

The behaviour manager 112 prepares a response signal in response to the alert signal which indicates the decision of the behaviour manager 112 and any conditions applied and addresses this to the MS 109 which it recognises as the MS which sent the alert signal. The response signal may also be copied to the network control terminal 114. The response signal to the MS 109 is sent via the ETS 103 as an over the air radio signal to the transceiver 203 of the MS 109 and is thereby passed to the processor 202 of the MS 109. The processor 202 recognises the response signal and takes action as instructed in the response signal.

Where the processor 202 is instructed not to allow a particular data transmission to continue where the data is of a first type, e.g. text data, the processor 202 may be allowed to continue to send and receive transmissions of a second type of data, e.g. video data, provided that such transmissions do not violate the rules for transmission of such data. Similarly, where the processor 202 is instructed not to allow a particular data transmission to continue, the processor 202 may be allowed to continue to send and receive transmissions of speech information.

Alternatively or in addition, where the behaviour manager 112 decides not to allow a particular data transmission to continue, the behaviour manager 112 may take other actions. For example, the behaviour manager 112 may decide that the MS 109 should be isolated and prevented from making further transmissions to the network via the system 100, or may be prevented from sending any transmissions of a particular data type, and may send an instruction message to the BTS 103 and/or to the MS 109 accordingly. The controller 201 of the MS 109 and/or the BTS 103 may be programmed to recognise such a message and to take the necessary isolation or prevention action.

The alert signal sent by the processor 202 of the MS 109 and the response signal sent by the behaviour manager 112 may themselves comprise short data messages, e.g. sent on a control channel of the communication system 100. These messages may comprise special codes according to a pre-defined protocol which are understood by the receiving terminal.

The operation of the shaping filters 311 and 313 and, if appropriate, the sending of an alert signal and the return of a response signal as described above are preferably carried out before the MS 109 has made a request to reserve data channel resource although, alternatively, may be carried out later, e.g. after a reservation request has been granted by the resource allocation processor 108.

The display 207 of the MS 109 may be operated to display a message indicating to a user, in relation to operation of the shaping filter 311 or 313, one or more of the following messages to provide information to a user of the MS 109: (i) that a violation of one or more rules relating to transmission of data has occurred; (ii) the extent or details of such a violation; (iii) that the intended transmission of data has been suspended or stopped; (iv) that a query has been sent to a system controller or manager to determine whether the intended transmission may be allowed despite the violation of one or more rules; (v) the result of a response signal received by the MS 109; (vii) that the MS is given special priority to send the data despite the rule violation; (viii) updates relating to rules to be applied relating to the sending of data; (ix) progress in sending the data.

Alternatively, or in addition, a feedback message may be sent to the internal or external data application from which the data has been delivered. Where the data application is being run externally to the MS 109, the message may be displayed on an external display unit (not shown) connected to a device running the application, e.g. a display connected to the computer 306 in FIG. 3.

Where the system 100 comprises a large network of a commercial operator with many users, as distinct from, say, a public safety network intended to provide mission critical services, it is likely that the behaviour manager 112 will comprise a processor running a computer program that automatically makes intelligent decisions relating to allowance or refusal of the intended transmission of data based on a set of pre- configured rules. However, for a public safety network supporting mission critical services (which generally will have far fewer users than a commercially operated network) it is possible that the behaviour manager 112 may comprise a communication terminal monitored by a human operator and the operator may be capable of using his/her expertise and knowledge (or thatof a colleague or manager) and may be capable of making or obtaining the appropriate decision and sending the response back to the MS that originated the alarm. Thus, the alert signal sent by the MS 109 may be received by a terminal within the infrastructure 102 and brought to the attention of a human operator, e.g. a system controller, e.g. by provision of a displayed message on a display of a control console (not shown) . The human operator may make or obtain a decision as to whether the intended data transmission is allowed to proceed and, if it is allowed, any conditions to be included. This operator may then initiate sending of the response signal to the MS 109 giving the decision and any related conditions.

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In an alternative embodiment of the invention, the MSS such as the MS 109 may store and apply more than one threshold value for a particular parameter defined in one or more of the rules operated by the shaping filters 311 and 312. For example, a first threshold and above may define an undesirable behaviour which causes generation of an alert signal for sending to the infrastructure 101 as described earlier. A second threshold and above may define an unacceptable behaviour which causes the MS 109 simply to prevent the transmission from proceeding. Thus, in these examples, the intended transmission of data is compared in the appropriate shaping filter 311 or 313 with the two thresholds to determine whether either of the thresholds is reached or exceeded and either generates an alert signal if only the first threshold is reached or exceeded and/or prevents transmission if the second threshold is reached or exceeded as well.

In another embodiment of the invention, the rules applied in each of the filters 311 and 313 could allow the filter to decide to respond differently to a violation depending on the priority assigned by the user to the data. For an example, the filter 311 or 313 could decide to send an alert signal (or block a transmission) as described earlier in the case of a small violation by a vehicle position-reporting data application in a police car normally patrolling a motorway because this is considered to be routine information only. However, if the police car starts a high-speed pursuit of, say, a bank robber then the vehicle position-reporting becomes highly important. The priority of the data application in this case may for example be raised by a police officer in the car by pressing an emergency button on his car dashboard radio acting as the MS 109. A signal indicating such a change in priority is produced as a result and is recognised by the MS 109 in the controller 201 and processor 202 (including the filters 311 and 313) and is also sent to the behaviour manager 112. This may also cause update messages produced by the MS 109 reporting the position of the car to be sent more frequently. These high priority messages are much more interesting and important to the police so the filters 311 and 313 can be programmed to recognise the increased priority and set to allow certain rule violations, possibly even large scale violations.

Similarly, user class and user ID can be used to achieve differential handling of services in the filters 311 and 313. The "data pipe" provided by the wireless network (including the system 100) is finite and it is unlikely that its capacity can be easily changed in real time. Having differential filtering helps to manage in real time (i.e. as situations change and develop) how this capacity is shared between different data applications running on or connected to one MS and/or spread across other MS5.

As noted earlier, the alert signal generated and sent by the processor 202 of the MS 109 may be sent additionally to the network control terminal 114 which is a dedicated control terminal (other than associated with the behaviour manager 112), via the BTS 101. The network control terminal 114 may be operated by or on behalf of a person who is a network control manager or quality of service manager. Such a manager may maintain a log of such alert signals to be aware for example if the signals are being sent from a particular source or particular sources. Such a log can be helpful if the manager has to have a discussion or correspondence with the user of the MS(s) that generated the alert signals.

For instance, a user might perceive a communications service performance that is worse than expected and may make a complaint. By receiving the alert signals the manager will be able to have a better awareness of the events which has taken place at the user's MS.

The embodiments of the invention described above beneficially allow recognition that a problem exists with an intended transmission of data and identification of the source of the problem and allow suitable corrective action to be taken either by denying a service of transmission, modifying an intended transmission or alerting the infrastructure or a system manager so that a decision on allowance of the transmission can be taken. Alternatively, or in addition, other action can be initiated, such as identification and implementation of changes in the network configuration to support higher data capacity, and/or corrective redesign of an application that misbehaves.

Overall, the service is generally improved for users of the system 100 by avoiding data transmissions which would cause a problem in the system 100, e.g. by unnecessarily adding to congestion or by spreading a virus or other unwanted defect. This is particularly beneficial to networks providing mission critical services since it ensures that the integrity of the service for other users (running well behaved data applications) is maintained. For networks of commercial operators this is beneficial because it ensures that such other users are not prevented from accessing the network, which helps to maintain the network operator's revenue stream and customer satisfaction targets.

In addition, the processor in which the shaping filters 311 and 312 are operated, e.g. the processor 202 of the MS 109, may send reports defining activity of the filters 311 and 312 from time to time to the system infrastructure 101. Beneficially, this allows statistical data from all MSs operating in a given site or cell to be collected in the infrastructure, e.g. by storage of the received data in the memory 107 of the infrastructure 101.

It is to be noted in the embodiments described above that an intended data transmission, and subsequent transmissions of the same data type, can be cut off by a decision made in some circumstances by either the MS from which the transmission is intended, e.g. the MS 109, or in other circumstances from the infrastructure 101, or possibly by entering a negotiation procedure between the MS and the infrastructure 101.

Claims (31)

1. A user terminal for use in a mobile communication system, the user terminal including a processor operable to monitor data intended to be sent via a communication resource of the system to another terminal and to detect whether the intended data transmission conforms with or violates one or more pre-defined rules defining well behaved data transmission and, if violation of one or more of the rules is detected, to initiate a procedure to determine if the data transmission is allowed to proceed.

2. A user terminal according to claim 1 wherein the procedure includes producing an alert signal for sending to an infrastructure of the system.

3. A user terminal according to claim 1 or claim 2 wherein the procedure includes producing an alert signal and sending the alert signal via the infrastructure to a system control terminal.

4. A user terminal according to any one of claims 1 to 3 wherein the procedure includes the processor determining by reference to a user identity or a user class or group of a current user of the user terminal or to a current mode of use of the user terminal that the data transmission is to be allowed to proceed despite a detected rule violation.

5. A user terminal according to any one of the preceding claims wherein the processor is operable to allow the intended transmission of data to proceed if no violation of the pre-defined rules is detected.

6. A user terminal according to claim any one of the preceding claims wherein the processor is operable to stop the intended data transmission taking place if a violation of one or more of the pre-defined rules is detected, optionally pending receipt of an instruction signal from the infrastructure.

7. A user terminal according to any one of claims 2 to 6 which is operable to receive a signal from the infrastructure giving an instruction indicating whether or not the intended data transmission is allowed to proceed and to follow the instruction.

8. A user terminal according to claim 7 wherein the instruction is to allow the intended data transmission to proceed following temporary stopping of the transmission when the violation of one or more of the predefined rules was detected by the processor.

9. A user terminal according to any one of the preceding claims 2 to 8 wherein the alert signal includes one or more of: (i) what rule or rules are violated; (ii) an extent or details of rule violation; (iii) an identity of the user terminal and/or its user and/or a class or group of users to which the user belongs; (iv) an estimate of the current location of the user terminal; (v) the current time; (vi) an identity of the site (cell) currently serving the MS; (vii) a data packet identity; (viii) an identity of a data application running from which the data has been delivered; (ix) a type of data.

10. A user terminal according to any one of the preceding claims wherein the processor is operable to classify data intended to be transmitted into different data types and to apply different sets of pre-determined rules to the intended transmission of different data types.

11. A user terminal according to claim 10 wherein the different data types include video data and text or numeric data.

12. A user terminal according to any one of the preceding claim which is operable to continue sending data of one type and/or voice communications when it has been stopped from sending of data of another type.

13. A user terminal according to any one of the preceding claims wherein the processor is operable to apply one or more pre-defined rules which relate to one or more of: (i) use of a particular data packet transmission protocol; (ii) an observed rate of data or data packet transmission; (iii) detection of a behavioural signature of a virus or other reproducible defect in the data; (iv) in order to be sent with a special level of priority or permission the data must be sent from a mobile station associated with a particular user type or class or a by particular user identity.

(v) data is allowed to proceed only if the application from which the data is are sent is an allowed data application.

14. A user terminal according to any one of the preceding claims which is operable to receive a wireless signal from a processor of the infrastructure giving information indicating one or more rules to be applied by the processor of the user terminal and to extract and store the information and wherein the processor of the of the user terminal is operable to apply the one or more rules indicated in the information.

15. A user terminal according to claim 14 wherein the information indicates one or more changes to previously notified rules.

16. A user terminal according to any one of the preceding claims which is operable periodically to send reports to a system infrastructure relating to detection activity by the terminal as to whether intended data transmissions conform with or violate one or more pre- defined rules and/or actions taken in response to such detection.

17. A user terminal according to any one of the preceding claims wherein the processor is operable in applying one or more of the pre-defined rules to detect whether a first threshold value but not a second threshold value of a parameter defined in the rule is reached or exceeded, and, if it is, to generate an alert signal, and to detect whether the second threshold value is reached or exceeded and, if it is, to prevent the intended transmission of data.

18. A user terminal according to any one of the preceding claims including a display operable to indicate to a user a message relating to allowance and/or stopping and/or transmission progress of the intended transmission of data.

19. A user terminal according to any one of the preceding claims which comprises a mobile station.

20. A user terminal according to any one of the preceding claims which includes a data input connection to enable the terminal to receive data for transmission from an external device or a network of external devices.

21. A user terminal according to any one of preceding claims which is operable according to an industry standard communication protocol.

22. A user terminal according to claim 18 which is operable according to the TETRA standard protocol, the GPRS protocol, the CDPD protocol or any other wireless protocol that supports data transmission.

23. A processor for use in an infrastructure of a mobile communication system which processor is operable to receive an alert signal from a user terminal indicating that one or more pre-defined rules defining well behaved data transmission will be violated (or is in the process of being violated) by an intended data transmission from the mobile station, to determine whether or not the intended data transmission is allowed to proceed and, at least when a result of the determination is to allow the intended transmission to proceed, to issue a response signal for sending back to the user terminal indicating a result of the determination.

24. A processor according to claim 23 wherein the response signal includes one or more conditions relating to an allowance of the proposed data transmission to proceed.

25. A processor according to claim 23 or claim 24 which is operable to make the determination by reference to information possessed by the processor relating to current deployment of user terminals in the communication system or of the user terminal which sent the alert signal or to an identity, group or class of a current user of the user terminal which sent the alert signal.

26. A mobile communication system including a plurality of user terminals each operable in accordance with any one of claims 1 to 22 and a system infrastructure operable to receive an alert signal from one of the user terminals indicating that one or more pre-defined rules defining well behaved data transmission will be violated by an intended data transmission from the mobile station in order for a determination to be made as to whether or not the intended data transmission is allowed to proceed, and, at least when the intended transmission is allowed to proceed, to issue a response signal for sending back to the user terminal indicating the result of the determination.

27. A method of operation in a mobile communication system including the steps of (i) a processor of a user terminal monitoring data intended to be sent via the system to another terminal and detecting whether the intended data transmission conforms with or violates one or more pre- defined rules defining well behaved data transmission; and, if the violation of one or more of the rules is detected, initiating a procedure to determine if the data transmission is allowed to proceed.

28. A method according to claim 27 wherein the procedure includes: (i) producing an alert signal; (ii) sending the alert signal from the user terminal to an infrastructure of the system; (iii) determining by receipt of the alert signal at the infrastructure whether or not the intended data transmission is allowed to proceed and (iv), at least when a result of the determination is to allow the intended transmission to proceed, sending back to the user terminal from the infrastructure a response signal indicating a result of the determination.

29. A user terminal according to claim 1 and substantially as described herein with reference to the accompanying drawings.

30. A processor according to claim 23 and substantially as described herein with reference to the accompanying drawings.

31. A system according claim 26 and substantially as described herein with reference to the accompanying drawings.