GB2453522A

GB2453522A - Call monitoring within a communication system being tetra compatible

Info

Publication number: GB2453522A
Application number: GB0717357A
Authority: GB
Inventors: Peter Sandberg
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2007-09-07
Filing date: 2007-09-07
Publication date: 2009-04-15
Anticipated expiration: 2027-09-07
Also published as: GB0717357D0; GB2453522B

Abstract

A wireless communication unit is capable of monitoring a plurality of calls over a network, and comprises signal processing logic arranged to prioritise at least one call to be monitored and to provide at least one call priority of the at least one call to be monitored to a network element. A Terrestrial Trunked Radio (TETRA) system is known to be able to monitor multiple calls at the same time. It is known for congestion to arise and a choice of call/transmission to be dropped being made based on a length of time since a call/transmission was last established. The dropping of a call can be disruptive to the parties involved and as TETRA is used widely within private mobile radio environments by emergency services and the like, the invention aims to enable the monitoring of a plurality of calls and the management of them in accordance with call priorities.

Description

METHOD AND APPARATUS FOR CALL MONITORiNG WITHIN A

COMMUNICATION SYSTEM

TECHNICAL FIELD

The technical field relates generally to a method and apparatus for monitoring one or more calls within a communication system.

BAC KG ROUND

In wireless communication systems such as the TErrestrial Trunked RAdio (TETRA) system, developed by the European Telecomniunjcatjons Standards Institute (ETSI), and defined by a plurality of ETSI standards, including ETSI EN 300 392-2, it is known for communication devices, for example mobile stations (MSs) such as handheld and/or vehicle mounted radio handsets, to he able to monitor multiple calls at the same time.

By way of example, a TETRA compliant MS may be a member of a plurality ofgroups, say fbur. The MS is able to connect with a Switching and Management Infrastructure (SwMI) of a TETRA network via a base station (BS), and in particular via a radio air interface between the MS and the BS. An MS is ollen rcIrred to as being attached' to a BS in this manner. Each BS is capable of transmitting and receiving communication traffic, such as speech or data, over four channels.

Accordingly, assuming that no other traffic is being transmitted or received by the BS, the MS is able to monitor up to four group calls at a time, one on each channel.

In order to accomplish this, the SwMI, of which the BS forms a part, is required to establish a connection for each of the applicable calls, following a request from the MS. The MS then determines which particular call to monitor/participate in at any one time, and is able to change the call it monitors as required. In this manner, the MS is able to monitor the various group calls, without having to request a new connection each time it changes the call that it wishes to participate in.

As will be appreciated by a skilled artisan, it is generally the case that more than one MS is attached to a BS at any one time. Accordingly, since the BS is only capable of' transmitting over four channels, these four channels can quickly become congested, with the BS receiving requests for connections to more calls than can be accommodated. Consequently, other calls being received by the BS from the network, inlended for an MS attached thereto, will not be able to gel through. Nor will an MS attached thereto be able to establish a new call via the BS.

To cope with this congestion, the TETRA system comprises supplementary services of Access Priority' and Priority Call', both of which are well known in the art, and are defined in ETSI standard ETSI EN 300 392-2. Access Priority allows a user to gain access to the network when the radio link is congested. In this manner, an MS is able to obtain access to the network when the radio link, namely the radio air interlhce, to the BS is congested by requesting the BS to drop an existing call or transmission in order to free up a channel for its own use.

Jo With Priority Call, the SwMl will provide pnority access to network resources to calls that have been sent with priority status. Although the BS to which an MS is attached may not be experiencing congestion, it may be the case that the network may be experiencing congestion elsewhere. For example, the MS may require a call to be established between itself and a second communication device, wherein the BS to which the second communication device is attached may be experiencing congestion.

Accordingly, although the MS is able to connect to the network, it may not be able to establish a connection with the second communication device. By requesting a priority call be established, the BS to which the second communication device is attached will drop an existing call or transmission, in order to free up a channel so that a connection to the second communication device may be established.

It is generally the case that the choice of call/transmission to be dropped is made based on a length of time since a call/transmission was last established. That is to say, the call/transmission that has been established for the longest period of time is dropped, unless of course it has a priority status. As will be appreciated by a skilled artisan, the dropping of a call can be disruptive to those parties involved.

Furthermore, communication systems such as TETRA are widely used within private mobile radio environments by emergency services and the like. Accordingly, the unwanted dropping of calls/transmission niay have severe adverse affects.

Thus, there exists a need for a method and apparatus for enabling a monitoring ofone or more calls within a cellular communication system, which addresses at least some of the shortcomings of past and present call monitoring techniques and mechanisms.

SUMMARY OF THE INVENTiON

According to embodiments of the invention, there is provided a wireless Conifliuflication unit, a network element, a communications system, a method for monitoring at least one call over a wireless communication network and a method for enabling monitoring of al least one call as set forth in the appended claims.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, where like reference numerals refir to identical or functionally similar elements throughout the separate views, which together with the detailed description below are incorporated in and Ibrm part of the specification and serve to further illustrate various embodiments of concepts that include the claimed invention, and to explain various principles and advantages of those embodiments.

FIG. I illustrates a block diagram of part of a wireless communication unit in accordance with some embodiments.

FIG. 2 illustrates a block diagrani of the wireless communication unit of FIG. I and a network element in accordance with some embodiments.

FIGs. 3 to 5 illustrate examples of call monitoring in accordance with some embodiments.

FIG. 6 illustrates a flowchart of a method of monitoring one or more calls according to an embodiment.

FIG. 7 illustrates a flowchart of a method of enabling the monitoring of one or more calls according to an embodiment.

FIG. 8 illustrates a flowchart of a method of enabling the monitoring of one or more calls according to an embodiment.

FIG. 9 illustrates a flowchart of a method of enabling the monitoring of one or more calls according to an embodiment.

Skilled artisans will appreciate that elements in the figures arc illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the diniensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. Apparatus and niethod components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, conimon and well-understood elements thai are useful or necessary in a commercially tasible embodiment may not be depicted in order to liicilitate a less obstructed view oithese various embodiments.

DETAILED DESCRIPTION

Generally speaking, pursuant to the various embodiments, in accordance with a iirst aspect there is provided a wireless communication unit capable of monitoring a plurality of calls over a network infrastructure, the wireless communication unit comprising signal processing logic adapted to prioritise the calls to be monitored and to provide call priorities of the calls to be monitored to the network infrastructure.

In accordance with a second aspect, there is provided a network element, forming part of a network infrastructure, and arranged to receive a request from a communication device for the monitoring of one or more calls: the network element comprising signal processing logic adapted, upon receipt of such a request, to establish a connection for one or more of the calls to be monitored in accordance with call priorities provided by the communication device.

In this manner, the network infrastructure is provided with priority information relating to those calls to be monitored. Accordingly, the network infrastructure is able to manage bandwidth and capacity in a more intuitive manner, especially during instances of congestion.

Those skilled in the art will realize that the above recognized advantages and other advantages described herein are merely illustrative and are not meant to be a complete rendering of all of the advantages of the various embodiments.

Referring now to the drawings, and in particular FIG. I, a block diagram of part ola wireless communication unit, or mobile station (MS), which in the context of the illustrated embodiment is in the fomi of a handheld radio handset, in accordance with sonic embodiments is shown and indicated generally at 100. Those skilled in the art, however, will recognize and appreciate that the specifics of this example arc merely illustrative of sonic embodiments and that the teachings set forth herein are applicable in a variety of alternative settings. For example, since the teachings described do not depend on a wireless communication device, they can be applied to any type of communication device adapted to monitor a plurality of calls, although part of a wireless communication device is shown in this embodiment. As such, other alternative implementations of dilThreni types of communication devices are contemplated and are within the scope of the various teachings described.

The MS 100 comprises an antenna 102, and a variety of radio frequency (RF) components or circuits 106, operably coupled to the antenna 102, that are well known in the art and will not be described further herein. The communication unit 100 further comprises signal processing logic 108. An output from the signal processing logic 108 is provided to a suitable user interttce (UI) 110 comprising, for example, a display, keypad, loudspeaker and/or microphone.

The signal processing logic 108 is coupled to a memory element 116 that stores operating regimes, such as decoding/encoding functions and the like and may be realised in a variety of technologies such as random access memory (RAM), read 1 5 only memory (ROM), Flash memory or any combination of these or other memory technologies. A timer 11 8 is typically coupled to the signal processing logic 108 to control a timing of operations within the communication unit 100.

In accordance with one embodiment, the MS 100 is capable of monitoring multiple calls over a network infrastructure. The signal processing logic 108 comprises call monitoring logic 122 adapted to priorilise calls to be monitored, and to provide call priorities for the calls to be monitored to a network infrastructure, for example a base station to which the MS 100 is attached.

Referring now to FIG. 2, there is illustrated a block diagram of the MS 100 of FIG. I, and a network element, which for the illustrated embodiment is in the form of Base Station (BS) 210, forming a part ofa network infrastructure, such as a Switching and Management Infrastructure (SwMl) of a TErrestrial Trunked RAdio (TETRA) network. The BS 2 10 comprises transceiver cIrcuitry 220, signal processing logic 230 and memory element 240. In accordance with one embodiment, the signal processing logic 230 of the BS 210 is adapted to receive a request from MS 100, for example in a form of a call monitoring set-up message, to set up call monitoring for one or more calls, and to establish connections for one or more of the calls to be nionilored in accordance with call priorities provided by MS 100.

The signal processing logic 108, or niore specifically for the illustrated embodiment the call monitoring logic 122, of the MS 100 is adapted to generate the call monitoring set-up message, which the signal processing logic 108 forwards to the RF circuitry 106 for transmission to the BS 2 10 via antenna 102. The call monitoring set-up message comprises details of one or more calls thai are desired to be monitored by the signal processing logic 108. In accordance with an embodiment of (he invention, prior to generating the call monitoring set-up message, the signal processing logic 108, or again niore specifically for the illustrated embodiment the call monitoring logic 122, priorilises the calls to he monitored. The call monitoring set-up message is then generated, comprising the call priorities.

The call monitoring set-up message is received by the transceiver circuitry 220 olihe BS 210, and passed onto the signal processing logic 230, which extracts the information relating to the calls to be monitored and their priorities and, for example, stores them in memory element 240. The BS 210 may also provide the call monitoring and priority information to further elements within, for example, the SwMI of a TETRA network such as a local switching centre (not shown). The signal processing logic 230 of the BS 2 10 subsequently assigns one or more traffic channels for the calls to be monitored.

In this manner, the SwMI is provided with priority infonnation relating to those calls to be monitored. Accordingly, the SwMI is able to manage bandwidth and capacity in a more intuitive manner, especially during instances of congestion, than is currently the case within, for example, known TETRA systems.

Refl.rring now to FIG. 3, there is illustrated an example 310 of call monitoring between MS 100 and BS 2 10 in accordance with one embodiment. For the illustrated embodiment, the BS 210 forms a part of a network infrastructure, such as the SwMI of a TETRA network. Accordingly, the BS 2 10 is adapted to provide four traffic channels. For the scenario illustrated in FIG. 3, the MS 100 has sent a call monitoring set-up message to the BS 2 10 wherein the MS 100 has requested to monitor four calls, and has priorilised those calls, as indicated in Table I below: Cal l_# I Priority 1 Cal l_#2 Priority 2 Call #3 Priority 3 (all #4 j Priority Table I: Example of call priorities For the scenario illustrated in FIG. 3, no other devices attached to BS 210 are involved with sending or receiving traffic, and so all thur channels are available to the MS 100. Accordingly, the BS 2 10 assigns each of the four calls to he monitored to one of the available channels. In this manner, the MS 100 is able to select a relevant channel in order to participate in a required call.

Referring now to FIG. 4, there is illustrated an example 410 of call monitoring between MS 100 and BS 2 JO of FIG. 3 wherein a Ilirther device 400, attached to the BS 210 requires a traffic channel. For example, the BS 210 receives a new call connection request, either from the further conimunication device 400 in a case of an outgoing call, or from within the SwMI in the case of an incoming call. Since all four channels have their calls to be monitored by N/IS 100 assigned thereto, in order for the BS 210 to establish the new call connection, it is necessary for one of the channels to he freed up, that is to say for one of the monitored calls to be terminated.

In accordance with an embodiment of the invention, the BS 210 terminates the monitored call with the lowest priority, freeing up a traffic channel. For the example illustrated in Table I above, (all #1 has the lowest priority, namely priority I, and as such would be terminated. The BS 210 is then able to assign the new call to the free channel, and establish the connection therefor. In this manner, although one of the calls being monitored by MS 100 has been terminated, due to the prioritisation of the monitored calls by the MS 100, the call of the lowest priority can be terminated, allowing calls of higher pnority, e.g. more important calls, to be maintained, whilst enabling channels to be freed up for other communications when required.

Referring now to FIG. 5, there is illustrated a further example 510 of call monitoring between MS 100 and BS 210 of FIGs. 3 and 4 wherein a second further communication device 500, attached to the BS 2 10 requires a traffic channel, for example in order for a new call connection to be established. Once again, the BS 210 is able to identify the monitored call of lowest priority, in order for that call to be terminated, and to free up a traffic channel for the new call.

Aswllbappredated,whntheMSsendsas1g the BS 210, there may not be enough free traffic channels for all calls to be assigned to traffic channels. Accordingly, the BS 210 may assign those calls with the highest priority to available traffic channels. For example, the 85210 may receive a call monitoring set-up request for four calls to be monitored, but where only two traffic channels are free. The BS 210 thus identifies the two calls to be monitored with the highest priorities, which for the example in Table I above would be Call_#3 and Call #4, and assigns these to the two free traffic channels.

Furthermore, when a channel becomes available, for example when one of MS 400 or MS 500 terminates its respective call, the SwMl may re-assign the freed-up channel to a call to be monitored that is not currently assigned a traffic channel. In particular, the freed-up channel may be assigned to the call comprising the highest priority of those not currently assigned a traffic channel.

Thus, the prioritisation of the calls to be monitored by the MS 100 enables the 85210 to intuitively select those calls to be assigned traffic channels when there are not enough free traffic channels available.

In an alternative embodiment, when the SwMI receives a call monitoring set-up request from an MS to set up call monitoring for one or more calls, the SwMl may only assign one traffic channel for monitoring the requested calls, namely a traffic channel that is not assigned to the call having the highest priority. When that call is subsequently terminated, the SwMI then re-assigns the traffic channel to the call having the next highest priority. In this manner, only a single traffic channel is required, whilst enabling an MS to monitor the call with the highest priority. Once that call has terminated, the SwMl intuitively assigns the next highest priority call to the same traffic channel, without the need for the MS to rcqucst a new connection for that call, or even to switch channels.

Referring now to FIG. & there is illustrated a flowchart 600 of a method for monitoring one or more calls according to one embodiment. The method of FIG. 6 may be implemented by, for example, a mobile station such as MS 100 of FIG. I. The method starts at step 610, and moves to step 620, where calls to be monitored are prioritiscd. By way of example, a user of an MS may select one or more groups, from thoscthattheM5isamember,viaainoftheMsselcallstobe monitored. The user may then order those groups within a list, or similar graphical representation of the groups, to represent the priorities of those calls relative to one another. Signal processing logic, such as signal processing logic 108 of FiG. 1, may then assign a priority value to each of the groups, and thereby to calls associated with those groups, according to their relative position from within the list.

Alternatively, calls may he prioritised according to a predefined priority order for groups to which the calls relate. For example, a list or table comprising each group of which the MS is a member may he stored in memory. The location of each group within the list or table may relate to the priority of that group relative to other groups of which the MS is a meniher. In this manner, when a user selects groups for which calls relating thereto are to be monitored, the priority of' those calls may be determined based on a position of the groups relative to one another within the list or

table.

Alternatively still, calls niay be prioritised according to a predelined priority value for groups to which the calls relate. For example, a list or table comprising each group of which the MS is a member niay be stored in memory, along with a priority level value associated with each group. In this manner, when a user selects groups for which calls relating thereto are to be monitored, the priority of those calls may be determined based on priority level values of' the selected groups.

Next, in step 630, a call monitoring set-up niessage is generated and sent to a network infrastructure, such as the SwMI of a TETRA network. The call monitoring set-up message comprises information identifying those calls that are desired to be monitored, as well as their priorities.

Having sent the call monitoring set-up message, the next step 640 comprises receiving traffic channel assignnient(s). For example, the MS may receive from the network infrastructure a traffic channel assignment for each call to be monitored, or in a case where a number of calls to be monitored exceeds a number of available traffic channels, one or more trallic channel assignments for calls having the highest priority.

In this embodiment, the number of traffic channel assignments may depend on the number of available traffic channels. In this manner, when an in sufficient number of traffic channels are available for all desired calls to be monitored, those calls with the highest priority are assigned traffic channels.

Alternatively, step 640 niay comprise receiving a single traffic channel assignment for a call with a highest priority. In this manner, the call with the highest priority may be monitored. Subsequently, when this call is terminated, the call with the next highest priority may he assigned to that traffic channel for the purpose of monitoring. In this manner, only a single traffic channel is taken up for the purpose of monitoring calls, whilst enabling the MS to monitor the call with the highest priority.

Having received the traffic channel assignment(s) in step 640, the next step comprises switching to the required traffic channel, for example the traffic channel to which the call with the highest priority is assigned, in step 650. The method then ends at step 660.

Referring now to FIG. 7, there is illustrated a flowchart 700 of a method for enabling a monitoring of one or more calls according to one embodiment. The method of FIG. 7 may be implemented by a network infrastructure, such as the SwMI of a TETRA network. The method starts at step 710, with a receipt of a call monitoring set-up message, say from MS 100 of FIG. 1, which comprises information identifying those calls that arc desired to be monitored, as well as their priorities.

1 5 Next, in step 720, the calls to be nionitored, and in one embodiment their respective priorities, are registered, for exaniple stored in memory, and one or more traffic channels are assigned. For example, a traffic channel niay be assigned for each call to be monitored, or in a case were a number of calls to be monitored exceeds a number of available traffic channels, available traffic channels are assigned to those calls with the highest priority. Alternatively, a single traffic channel niay be assigned to a call with a highest priority.

The method then nioves to step 730, where the traffic channel assignment(s) is/are sent to the source of the call monitoring set-up message. A Connection Ibr the, or each, call to which a traffic channel has been assigned is then established, in step 740. The method then ends at step 750.

Refrring now to FIG. 8, there is illustrated a flowchart 800 of a method of enabling a monitoring of one or more calls according to one embodiment. The method of FIG. 8 may be implemented within a network infrastructure, such as a base station lhrming a part of the SwMI of a TETRA network.

The method starts at step 810 with a receipt of a new call fbr which a connection or network resource is required. For example, a mobile station attached to a base station may request the network to establish a call between itself and a communication device elsewhere on the network. Alternatively, the base station may receive a call from elsewhere on the network, destined for a mobile station attached thereto.

having received a new call, the next step comprises determining whether there is a free traffic channel available for the new call, in step 820.

ha traffic channel is available in step 820, the method moves to step 830, where the new call is assigned to the available traffic channel, and a connection is accordingly established for the call. The method then ends, at step 890.

If there are no free channels available, the method moves to step 840, to determine whether prioritised call monitoring is in progress in step 840. Ii no prioritised call monitoring is in progress, the method moves to step 850, where the call having the longest duration is terminated in order to free up a channel. The method then moves to step 880, where the new call is assigned to the freed up traffic channel, and the method then ends at step 890.

The method then ends at step 890.

Refrring back to step 840, iiprioritised call monitoring is in progress, the method moves to step 860, where it is determined whether the prioritised call monitoring comprises more than one call. lithe prioritised call monitoring comprises monitoring only one call, the niethod moves to step 850, where the call having the longest duration is terminated in order to free up a channel. The method then moves to step 880, where the new call is assigned to the freed up traffic channel, and the method then ends at step 890.

lithe prioritised call monitoring comprises more than one call, the method moves to step 870, where the monitored call with the lowest priority is terminated, thereby freeing up a traffic channel for the new call. Next, in step 880, the new call is assigned to the freed up traffic channel, and the method then ends at step 890.

In this manner, network bandwidth, thr example traflic channels provided by a base station, which would otherwise be congested by a device, such as a mobile station, monitoring multiple calls, can be freed up intuitively, by terminating monitored calls with the lowest priority. This advantage is provided whilst enabling more important monitored calls, namely those with a higher priority, to be maintained.

Referring now to FIG. 9, there is illustrated a flowchart 900 of a method for enabling a monitoring of one or more calls according to one embodiment. The method of FIG. 9 may be implemented within a network infrastructure, such as a base station forming a part of the SwMI of a TETRA network.

For example, a mobile station attached to a base station may he monitoring a plurality of calls, for which the mobile station has previously prioritised, and provided such priorities to the SwMl as part ofa call monitoring set-up niessage. The SwMI, having received the call monitoring set-up message and assigned a traffic channel to a call to be monitored with the highest priority.

The method starts at step 910 with a termination of a call being monitored.

The next step, step 920, comprises determining whether any other calls to he monitored are active. That is to say, of those calls that the mobile station has requested to monitor, whether any of the calls are still in progress, or whether all calls have been terminated. If no other calls being monitored arc active, the method ends at step 950. Ii one or more calls to be monitored arc still active, the method moves to step 930, where the call to he monitored with the highest priority is identified.

Next, in step 940, the identified active call to monitor is assigned to the traffic channel previously assigned to the terminated call. The method then ends at step 950.

In this manner, when a mobile station, or the like, desires to monitor multiple calls, only a single traffic channel may be required, whilst enabling the mobile station to monitor the active call with the highest priority. As will be appreciated by a skilled artisan, the method of FIG. 9 substantially alleviates unnecessary redundancy caused by assigning traffic channels to a plurality of monitored calls, when a mobile station is only monitoring one call at any one time.

It is within the contemplation of the invention that the inventive concept described herein can be applied in any communication system in which the ability to monitor multiple calls is provided, wherein congestion may be reduced by way of prioritising calls to he monitored.

Ii will be understood that the communication units, fbr example mobile stations and the like, and methods for monitoring one or more calls or enabling the monitoring of calls, as described above, may provide one or more of the fhllowing advantages: (i) Intuitive management of bandwidth and capacity within a network infrastructure, as a result of providing the network infrastructure with prioritisation of monitored cal Is: (ii) Priorilisation of monitored calls by a mobile station, or other communication device, thereby enabling a user olsuch a device to detemiine a priority o I cal Is.

(iii) Improved reliability of call connection fbr high priority calls, by ensuring lower priority calls are terminated ahead of higher priority calls.

In the foregoing specification, specific embodiments have been described.

However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such moditications are intended to be included within the scope of present teachings. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential fatures or elements of any or all the claims. The invention is defined solely by the appended claims including any aniendnienls made during the pendency ofthis application and all equivalents of'those claims as issued.

Moreover in this document, the terms comprises,' comprising,' has', shaving,' Includes', including,' contains', containing' or any other variation thereoC are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by comprises. . .a', has. . .a', Includes. . .a', contains. . .a' does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms a' and an' are defined as one or more unless explicitly slated otherwise herein.

The terms substantially', essentially', approximately', about' or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art.

The term coupled' as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is configured' in a certain way is configured in at least that way, but may also he configured in ways that are not listed.

It will be appreciated that sonic embodiments may be comprised of one or more generic or specialized processors' (or processing devices') such as microprocessors, digital signal processors, customized processors and field programmable gale arrays (FPCiAs) and unique stored program instructions (including both sotware and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all ofihe functions of the method and apparatus for enabling the monitoring of one or more calls within a cellular communication system described herein. The non-processor circuits may include, but arc not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method to perform the monitoring of calls described herein. Alternatively, sonic or all functions could be implemented by a stale machine 1 5 that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or sonic combinations of certain of the functions are implemented as custom logic. Of course, a conibination of the two approaches could be used. Both the state machine and ASIC are considered herein as a processing device' for purposes of the foregoing discussion and claim language.

Moreover, an embodiment can be implemented as a computer-readable storage element having computer readable code stored thereon for programming a computer (e.g., comprising a processing device) to perform a method as described and clainied herein. Examples of such computer-readable storage elements include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) and a Flash memory. Further, it is expected that one of ordinary skill, notwithstanding possibly significant elIort and many design choices' motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and lCs with minimal experimentation.

The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various fatures are grouped together in various embodiments for the purpose of streamlining the (lisciosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all la1ures of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

Claims

What is claimed is: I. A wireless comniunicalion unit capable olnionitoring a plurality of calls over a network, the wireless communication unit comprising signal processing logic arranged to prioritise at least one call to he monitored from a plurality of monitored calls and to provide at least one call priority of the at least one call to be monitored to a network element.
2. The wireless communication unit of Claim I further characierised in that the signal processing logic is arranged to generate a call monitoring set-up message lobe sent to the network element.
3. The wireless communication unit oiClaim 2 further characterised in that the call monitoring set-up message comprises details olat least one call ofthe plurality of calls that is to be monitored.
4. The wireless communication unit of Claim 2 or Claim 3 further characterised in that the call monitoring set-up message comprises a call priority for the at least one call to be monitored.
5. The wireless communication unit of any preceding Claim further characterised in that prioritisation of at least one call of the plurality of calls to be monitored comprises the wireless communication unit selecting at least one call group of which the wireless communication unit is a member.
6. The wireless communication unit of Claim 5 further characterised in that the prioritisation of the at least one call to be monitored comprises ordering the at least one call group within a list olcall groups to represent at least one priority of those call groups relative to one another.
7. The wireless communication unit of any preceding Claim further characterised in that the prioritisation of at least one call to be monitored comprises prioritising the at least one call according to at least one oI a predelined priority order and a value for at least one call group to which the at least one call relates.
8. The wireless communication unit of any preceding Claim further characterised by the wireless conimunication unit being compatible with the TErrestrial Trunked RAdio (TETRA) standard.
9. A network element, forming pad of a network infrastruclure, and arranged to receive a request from a wireless communication unit to monitor at least one call of a plurality of monitored calls; the network element comprising signal processing logic arranged, upon receipt of such a request, to establish a connection for the at least one call to be monitored in accordance with at least one call priority provided by the wireless communication unit.
10. The network element of Claim 9 further characterised in that the request from the wireless communication unit is a call monitoring set-up message comprising information identifying the at least one call to he monitored and the at least one respective call priority.
11. The network element of Claim 9 or Claim 10 further characterised in that the signal processing logic is arranged such that establishing a connection for at least one call to be monitored comprises assigning at least one traffic channel to the at least one call.
12. The network element of Claim II further characterised in that the signal processing logic is arranged to assign at least one trallic channel to the at least one call to be monitored with the highest priority.
13. The network element of Claim 12 further characterised in that the signal processing logic is arranged to determine whether a free channel is available and, upon receipt of a new call and where there is no free channel available, the signal processing logic determines whether prioritised call monitoring is in progress.
14. The network element of Claim 13 further characterised in that the signal processing logic is arranged to determine whether the prioritised call monitoring comprises more than one call.
15. ihe network element of Claim 14 further characterised in that the signal processing logic, in response to determining that prioritised call monitoring for more than one call is in progress, terminates the monitored call with a lowest priority.
16. The network element of Claim 12 further characterised in that the signal processing logic is arranged to assign a single traffic channel to the at least one call to be monitored with a highest priority.
17. The network element of Claim 16 further characterised in that the signal processing logic is arranged, in response to a termination of a call being monitored, to determine whether at least one other call to be monitored is active.
18. The network element, of Claim 17 further characteriscd in that the signal processing logic is arranged to assign a traffic channel, previously assigned to the terminated call, to the at least one other active call.
19. The network element of any of Claims 9 Ic) 18 further characterised in that the network element forms a part of a TErrestrial Trunked RAdio (TETRA) communication system.
20. A cellular communication system comprising a network element arranged to receive a request from a wireless communication unit to monitor at least one call from a plurality of calls; the network element comprising signal processing logic arranged, upon receipt of such a request, to establish a connection fbr at least one of the at least one call to be monitored in accordance with call priorities provided by the wireless communication unit.
21. A method for monitoring at least one call of a plurality of monitored calls over a wireless comniunicat ion network, the method comprising: prioritising the at least one call to he monitored by a wireless communication unit; and providing at least one call priority of the at least one call to be monitored to a network element in the wireless communication network.
22. The method of Claim 21 further characterised by: generating a call monitoring set-up message to he sent to the network element, wherein the call monitoring set-up message comprises details of the at least one call to be monitored. 1 0
23. The method of Claim 21 or Claim 22 further characterised by: generating a call monitoring set-up message to be sent to the network element, wherein the call monitoring set-up message comprises a call priority for the at least one call to be monitored.
24. The method of Claim 21, Claim 22 or Claim 23 further characterised in that prioritizing comprises selecting at least one call group, from which the at least one call is to be monitored.
25. The method of Claim 21 further characterised by ordering those call groups within a list to represent the at least one priority of a plurality of the monitored calls relative to one another.
26. The method of Claim 21, Claim 22 or Claim 23 further characterised in that prioritizing comprises prioritising at least one call according to at least one of: a prede fined priority order and value for at least one call group to which the at least one call relates.
27. A method for monitoring of at least one call of a plurality of monitored calls, the method comprising: receiving a request to monitor the at least one call, wherein the request comprises at least oiie call priority of the at least one call to be monitored; and establishing a connection for the at least one call to be monitored in accordance with the at least one call priority; and monitoring the at least one call.
28. The method oiClaim 27 further characterised in thai establishing a connection comprises assigning at least one traffic channel to the at least one call to be monitored.
29. The method of Claini 28 further characterised by assigning at least one traffic channel to the at least one call to he monitored with the highest priority.
30. The method of Claim 29 further characterised by: determining whether a free channel is available; and upon determining that there is no free channel available, and upon receipt of a new call, determining whether prioritised call monitoring is in progress.
31. The method of Claim 30 further characterised by determining whether prioritised call monitoring comprises monitoring more than one call.
32. The niethod of Claim 31 further characterised by terminating the monitored call with the lowest priority iiprioritised call monitoring is in progress fbr more than one call.
33. The method of Claim 30 or Claim 31 or Claim 32 further characterised by determining whether any other calls to be monitored are active.
34. The method of Claim 33, upon determining that at least one other call to be monitored is active and upon termination of a call being monitored, assigning the traffic channel previously assigned to the terminated call to the active call to be monitored with the highest priority
35. A computer-readable storage element having computer-readable code stored thereon for programming a computer to form a method for monitoring at least one call of a plurality of monitored calls over a wireless communication network, the niethod comprising: prioritising the at least one call to he monitored: and providing least one call priority of the at least one call to he monitored to a wireless communication network.
36. A computer-readable storage element having computer-readable code stored thereon for programming a computer to form a method for monitoring at least OflC call of a plurality of monitored calls, the method comprising the steps oi receiving a request to nionitor the at least one call, wherein the request comprises at least one call priority of the at least one call to be monitored: and establishing a connection for the at least one call to he monitored in accordance with the at least one call priority.
37. The computer-readable storage element of Claim 35 or Claim 36 wherein the computer readable storage medium comprises at least one of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), a EPROM (Erasable Programmable Read Only Memory), a EEPROM (Electrically Erasable Programmable Read Only Memory) and a Flash memory.