GB2375924A

GB2375924A - Reporting measurement data in a mobile network

Info

Publication number: GB2375924A
Application number: GB0112735A
Authority: GB
Inventors: Georges Martinez
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2001-05-25
Filing date: 2001-05-25
Publication date: 2002-11-27
Anticipated expiration: 2021-05-25
Also published as: GB0112735D0; GB2375924B

Abstract

A network controller provides and transmits an operating parameter evaluation function to the mobile terminal. The evaluation function is a specification of the measurements to be used in a determination of whether to transmit a measurement report to the network. The report may contain the evaluation result and/ or other measured parameter values, such as the received power levels or interference level. The evaluation function may be selected so that when a report is transmitted to the network, the communication link or an operational instruction to the subscriber may be adjusted. The evaluation function may be altered depending upon the radio environment (indoor, outdoor), the type of service (web, voice, video) or the application.

Description

REPORTING MEASUREMENT DATA IN A COMMUNICATION SYSTEM Field of the Invention This invention relates to communication systems and particularly to subscriber terminals which measure operating parameters and transmit data related to the measured parameter values to a base station or a network controller which provides a communications service to the subscriber terminals. The invention is applicable to, but not limited to, mobile cellular radio communication systems.

Background of the Invention There are many types of communication systems comprising mobile terminals (also-known as mobile stations, mobile communication units, mobile subscriber units etc. ) and a network, sometimes referred to as a fixed network or serving network, providing communications service to the mobile terminals, via respective communications links established between a base station and each mobile terminal. The communications link is for example a radio or microwave link. One example of such a system is a cellular radio communications system, another example is a private land mobile radio system.

In many communication systems of the type described above, the mobile terminals perform measurements of operating parameters. The term "operating parameter" is used in this specification to mean any physical parameter related to the operation of the mobile terminal whose

value can be measured, and includes parameters sometimes alternatively referred to as"metrics"in certain communication fields. The term"measured"or"measuring" as applied to such operating parameters is used in this specification to include the mobile terminal directly measuring or deducing, estimating or in some other way arriving at a value of the parameter.

Furthermore, the mobile stations then report the measured parameter values to the network. In GSM (Global System for Mobile Communications) cellular radio communications systems, for example, the mobile terminals repeatedly measure the parameters and transmit the values thereof to a serving base station'in the form of measurement reports as defined in the GSM specification.

The measured values, i. e. measurement data, are then analysed by the base station or a network controller.

Depending on the values, the network controller may decide to alter an aspect of the communication link, e. g. may increase radio signal strength, or, in the case of a cellular system, may hand the mobile terminal off from a current serving base station to a neighbouring base station (as defined for example in the GSM specification).

Conventionally, the parameters to be measured are predetermined. Also, the mobile terminal then transmits all the measured parameter values to the serving base station. For example, in the case of GSM, the contents of the measurement reports are standardized, and thus an individual network operator cannot modify the contents of the measurement reports without the GSM standard being

changed. Also, the measurement reports are conventionally made and sent at prescribed intervals or events.

This conventional approach allows the mobile terminals to be relatively simple as they do not need to take decisions in this area, any decisions are taken by the base station or network controller.

In certain existing systems, a network controller can select on which predefined trigger a mobile terminal is to transmit a measurement report, or notify a situation change. However, even in these systems the selection procedure for the mobile terminal is predetermined and set as part of the overall system's standard. Thus, if new considerations were to be desired, they can be implemented only with changes in the standards and modifications to the mobile terminals.

The conventional systems described above suffer from the disadvantage or restriction that since the parameter values to be measured are predetermined, individual terminals will be measuring parameters that are perhaps of little significance to their operational circumstances. Moreover, because the measured data is transmitted"blind"and in full, some or all of the transmitted data may not be of any use. This disadvantageously wastes radio or other communications link resource, as well as operating time of the base stations and the mobile terminals.

Thus, there exists a need in the field of the present invention to provide an improved means for reporting measurement data in a communication system.

Summary of the Invention In a first aspect the present invention provides a subscriber terminal, as claimed in claim 1.

In a second aspect the present invention provides a network controller use in a communication system and as claimed in claim 6.

In a third aspect the present invention provides a method of operating a communication system, as claimed in claim 12.

In a fourth aspect the present invention provides a storage medium as claimed in claim 13.

The present invention provides further aspects as claimed in the dependent claims.

In summary, according to the invention, an evaluation function (or program or algorithm or process instructions) is provided in an updateable way from a network controller to a subscriber terminal. The subscriber terminal employs the evaluation function to determine what parameters to measure, and to perform preprocessing of the resulting measured parameter values, to determine whether to send measurement data. The evaluation function also specifies what data should be sent. Consequently, the above identified disadvantages of conventional systems are alleviated, since only parameters more likely to be relevant to a particular

mobile terminal are measured, and more pertinent resulting measurement data is actually transmitted. Hence the burden on the subscriber terminal, and the communications link resources are all potentially reduced. Also, the evaluation function can be adapted to a particular subscriber terminal's circumstances.

Brief Description of the Drawings FIG. 1 shows one cell of a cellular communication system.

FIG. 2 shows a block diagram of mobile telephone receiving service in the cell of FIG. 1.

FIG. 3 is a schematic illustration, in terms of functional elements, of an evaluation function employed by the mobile telephone of FIG. 2.

FIG. 4 is a message sequence chart showing an exchange of data between the network of the cellular communication system and the mobile telephone of FIG. 2.

FIG. 5 is a message sequence chart showing an exchange of data between a base station of the cellular communication system and a conventional mobile telephone receiving service in the cell of FIG. 1.

Description of Preferred Embodiments Embodiments of the invention are hereinafter described by way of example only.

In a first embodiment, the communication system is a cellular radio communication system. FIG. 1 shows a base station 104 coupled to a network controller 106 which provides service in one cell 108 of the overall system (for clarity other base stations providing service in other areas are not shown). A large number of mobile terminals receive service in cell 108 via respective radio links between the base station 104 and the mobile terminals, but for clarity only three are shown. Each of these mobile terminals is a mobile telephone, i. e. mobile telephone 110 with radio link 115, mobile telephone 120 with radio link 125, and mobile telephone 130 with radio link 135.

In the present embodiment, mobile telephones 110 and 120 are provided with means for receiving, storing and implementing an evaluation function provided by the network controller 106 via the base station 104 for determining a parameter measurement and reporting process, as will be described in more detail below, whereas mobile telephone 130 employs a conventional measurement reporting procedure as will also be described for comparison purposes.

FIG. 2 shows a block diagram of mobile telephone 110 (for simplicity only mobile telephone 110 will be described in detail, as in this embodiment mobile telephone 120 is the same as it). The mobile telephone 110 contains an antenna 202 coupled to a duplex filter or circulator 204 that provides isolation between receive and transmit chains within the mobile telephone 110.

The receiver chain, as known in the art, includes

scanning receiver front-end circuitry 206 (effectively providing reception, filtering and intermediate or baseband frequency conversion). The scanning front-end circuit is serially coupled to a signal processing function 208.

An output from the signal processing function is provided to suitable output devices such as a loudspeaker 210, and other output devices, not shown, such as a display.

The receiver chain also includes received signal strength indicator (RSSI) circuitry 212, which in turn is coupled to a controller 214 which operates to maintain overall control of the different functions and modules of the mobile telephone 110. The controller 214 is also coupled to the scanning receiver front-end circuitry 206 and the signal processing function 208 (generally realised by a digital signal processor, i. e. DSP).

The controller 214 includes a memory 216 that stores operating regimes, such as decoding/encoding functions and the like, and data relating to a monitored list of suitable neighbouring cell sites. A timer 218 is typically coupled to the controller 214 to control the timing of operations (transmission or reception of timedependent signals) within the mobile telephone 110.

As regards the transmit chain, this essentially includes an input device such as a microphone 220, and other input devices, not shown, such as a keyboard. The input devices are each coupled in series through transmitter/modulation circuitry 222 and a power amplifier 224 to the antenna 202. The transmitter/modulation circuitry 222 and the

power amplifier are operationally responsive to the controller.

The various components within the mobile telephone 110 are realised in this embodiment in integrated component form. Of course, in other embodiments, they may be realized in discrete form, or a mixture of integrated components and discrete components, or indeed any other suitable form. Further, in this embodiment the controller 214 including memory 216 is implemented as a programmable processor, but in other embodiments can comprise dedicated circuitry or any other suitable form.

It is noted that corresponding features to those described above with respect to mobile telephone 110 (and hence mobile telephone 120) are also found in conventional mobile telephone 130. However, mobile telephone 110 (and mobile telephone 120) differ over a conventional mobile telephone 130 by virtue that the controller 214, including memory 216, and where appropriate, the signal processing function 208 and the transmitter/modulation circuitry 222 is adapted to receive, store and implement an evaluation function in the manner which is described in more detail below.

The evaluation function of this embodiment is produced by the network 106 in the form of a Java W applet comprising processor-implementable instructions and/or data, but in other embodiments can be in any suitable form. The evaluation function is transmitted from base station 104 over radio link 115 to mobile telephone 110, where the processor-implementable steps and/or data which are stored in the memory 216 and accessed and processed by the processing parts of controller 214 as required.

FIG. 3 is a schematic illustration, in terms of functional elements, of the evaluation function 300 of this embodiment. The evaluation function comprises a specification 310 of which parameters the mobile telephone is to measure. The controller then only measures the specified parameters when performing parameter measurement. In the present embodiment, only some of the parameters the mobile telephone is capable of measuring are specified, although in other embodiments all such parameters can be specified. In this embodiment, the specified parameters are the interference level of signals received by the mobile telephone 110 from the serving base station 104 of the serving cell 108 (which is obtained by the mobile telephone 110 in a conventional manner, as for example described in the GSM specification) and received power levels from the best N neighbour cells (in this embodiment the best 6 cells, which again is obtained by the mobile telephone 110 in a conventional manner, as for example described in the GSM specification).

The evaluation function 300 further comprises a calculation algorithm 320 which specifies a calculation that is made using the measured parameter values. The evaluation function 300 further comprises a comparison algorithm 340 which compares the calculated result to a criterion or threshold, the result of which determines whether a transmit decision module 350 will provide for data to be transmitted or not. In the present embodiment the calculation is to produce an average interference figure, and the criterion or threshold determines whether

a threshold value of acceptable interference level is exceeded by this average value.

The choice of which measurement data is transmitted (if measurement data is indeed to be transmitted) is specified by a specification of data to be transmitted by module 330, which receives direct measured parameter values and/or other calculated or derivative values from or via the calculation algorithm 320. In this embodiment the data to be transmitted is (a) the status information that the measured interference is greater than the interference threshold, and (b) the six best neighbour signal strengths and the identities of these neighbour cells. In other embodiments the actual interference level could be included, as indeed could any other specified parameter or parameter-based data.

The process steps carried out under the present embodiment will now be described with reference to FIG.

4, which is a message sequence chart showing an exchange of data between the network controller 106 and the mobile telephone 110.

At step 405 the base station 104 starts connection set-up with the mobile terminal 110 by transmitting log-on data (for example, in response to a request for service from the mobile telephone 110). At step 410 the mobile telephone 110 and the network controller 106 exchange, via the base station 104, radio bearer parameters and other data required to establish the radio link 115 for communication of traffic data (i. e. as opposed to system set-up and/or control data).

At step 415 the base station 104 transmits the above described evaluation function 300, derived by the network controller 106, to the mobile telephone 110.

At step 420 the mobile telephone 110 and the network controller 106 exchange data, i. e. in this embodiment traffic data is exchanged (as opposed to signaling or control data), and more generally, this can be considered to be any data that is exchanged between the terminal and the network controller via the base station 104 other than the measurement data and subsequent messages instructing consequential changes in radio bearer settings etc.

In this embodiment the mobile telephone measures parameters, and implements the evaluation function 300 to determine whether measurement data is to be sent, at regular intervals after it has received the evaluation function at step 415, including during any exchange of traffic data such as at step 420. However, as is clear from the earlier description, this will only result in a determination to transmit measurement data when the above described criterion is met by the average interference exceeding the allowable threshold. In this embodiment, such an event occurs after the exchange of data at step 420 is completed, and consequently at step 425 the above described measurement data specified for transmission is indeed transmitted from the mobile telephone 110.

As represented in FIG. 4 by event box 428, some or other radio bearer settings will need to be changed. In this embodiment the network controller 106 does not need to

assess whether such a change in operational settings is required, because this fact is already known to it by virtue of the pre-processing carried out by the mobile telephone 110 using the evaluation function 300, in conjunction with the threshold being set at a level that, if exceeded, will definitely require adjustment of operation (in other embodiments the threshold or criterion can instead be set at a"cautionary"level that then requires the network to further analyse whether a change is required or not). Instead, in this embodiment, the network controller 106 merely determines an appropriate solution. Here, the network controller analyses the nearest neighbour powers to determine whether any such neighbouring cell would be a good handover candidate, but finding this not to be the case, instead changes the frequency protocol by which it and the mobile station 110 will communicate, i. e. power at which it transmits its signals to the mobile telephone 110. It transmits these new radio bearer parameters to the mobile telephone 110 at step 430. Thereafter, further exchange of data takes place at step 435, and here further parameter values do not lead to a requirement to transmit measurement data when processed using the evaluation function 300, until at step 440, communication ends. The procedure shown in FIG. 4 is then repeated whenever connection is again required, and either the same evaluation function 300 or a different evaluation function will then be transmitted at the step equivalent to step 415, depending on the current circumstances of the mobile telephone 110.

In this embodiment, the particular evaluation function 300, as earlier described, is selected for transmission

by the network controller 106 to the mobile telephone (at step 415) on the basis of an analysis of the radio bearer parameters received during exchange step 410. As such, the evaluation function is selected by the network controller as appropriate for the particular mobile telephone 110 in the light of the condition of the mobile terminal 110. In particular, in this embodiment the network controller assesses one or more of the following: the radio environment to be employed (e. g. whether the mobile telephone is in a vehicle or outdoors, which can be deduced by signal characteristics-e. g. the Doppler shift can be analysed to give an indication of user speed, or the shape of a channel profile can also indicate the type of user environment), the type of service (e. g. circuit-switched, packet switched etc. ) or the application to be employed during communication (e. g.

WEB browsing, voice, video etc. ). In other embodiments, other conditions or factors can be considered by the network controller when selecting an appropriate evaluation function for a particular mobile telephone or other mobile terminal.

Moreover, because the evaluation function is individually adapted or selected as appropriate for each mobile terminal, in this embodiment when the corresponding process to that shown in FIG. 4 is performed with respect to mobile telephone 120, a different evaluation function is sent at step 415 compared to that sent at step 415 to mobile telephone 110.

In this embodiment, the remaining mobile telephone 130 is a conventional one and hence cannot accommodate or employ an evaluation function. The process steps carried out

under conventional operation of communication between mobile telephone 130 and network controller 106 via base station 104 will now be briefly described for the sake of comparison. The steps are shown in FIG. 5, and those steps common to the operation of mobile telephone 110 are indicated by the same reference numbers as per FIG. 4 and will not be described again.

Conventional mobile telephone 130 performs measurement of all predetermined parameters at regular intervals, and each time transmits to the base station 104 as measurement data the measured values of all the parameters (thereby constituting each time a conventional measurement report). As shown in FIG. 5, transmission of such a measurement report occurs at step 510 and again at step 520. Of particular note when comparing with the procedure for mobile telephone 110, is that for conventional mobile telephone 130 a measurement report is transmitted at step 510, which then has to be fully analysed by the network controller 106, despite the fact that no change is required in response thereto by the network controller, since the measured parameter values are satisfactory. It is only for the measurement report transmitted at step 520 that a response is required (i. e. a change of radio bearer settings), and even then the network controller has to perform more analysis than was the case for mobile telephone 110. By comparing FIG. 5 with FIG. 4 it can be appreciated that one advantage of the present invention is to provide the possibility of more efficient reporting of measurement data by reducing the number of reports of data required to be transmitted from a mobile terminal. Moreover, those that are transmitted are either more likely to or definitely

require a response, thus reducing needless processing by a network controller or base station.

Furthermore, as explained by example with reference to the above embodiment, the evaluation function can be tailored according to specific needs dictated by the terminal environment.

Since mobile terminal complexity is less and less an issue, the present invention can require less measurement reports to be sent by the terminal without undue burden on the terminal design or cost. Thus, wireless bandwidth is saved, as well as unnecessary processing.

It will be appreciated that the present invention is applicable to any suitable communication system in which measured parameter values are reported from a mobile terminal or mobile station to a network controller or other network element such as a base station. This includes other radio or wireless systems in addition to cellular communications systems. In the case of cellular communications systems, this includes time division multiple access (TDMA), code division multiple access (CDMA) or combined TDMA/CDMA systems.

The evaluation function can specify parameters, algorithms and criteria other than those described in exemplary fashion above. Different parameters will be more relevant according to the type of communication system. (For example, in packet data systems such as GPRS, the terminals, and network elements, are allowed to store packets in a temporary buffer until the other party has acknowledged correct reception, so that the packets

can be retransmitted if necessary. In this case a parameter of interest may be the degree to how full a terminal's buffer is, i. e. buffer capacity status or similar. ) Also, the functional modules of the evaluation function described in the above embodiment can be arranged differently, or the corresponding functions thereof divided differently between different functional blocks or modules. Also, the evaluation function can be formed of different functional modules compared to those described in the above embodiments.

The evaluation functions can be obtained or produced by a network controller in any suitable fashion, e. g. by programming at one or more base sites, or obtained externally and downloaded to a network element in some suitable manner.

In the above embodiment, the invention is applied to mobile telephones. In other embodiments other types of mobile terminals or mobile stations can be employed instead or as well, such as personal computers with radio modems, electronic organizers, video players, audio players, etc.

The controller 214 in a mobile terminal described in the above embodiments can be embodied in any suitable form of software, firmware or hardware. Also, in addition to the evaluation function itself comprising processorimplementable instructions and/or data, additional operation of the processor 208 and other terminal components as used to implement the present invention can be controlled by processor-implementable instructions and/or data, for carrying out the methods and processes

described, which are stored in a storage medium or memory. The memory can be a circuit component or module, e. g. a RAM or PROM, or a removable storage medium such as a disk, or part of a subscriber identity module (SIM) or other suitable medium.

It will be understood that the communication system, communication unit and method for preprocessing of metrics in mobile terminals described above provides the following advantages: (i) the approach is based on the download of an evaluation function for the terminal locally evaluating a situation prior to reporting to the fixed network components.

(ii) a network controller can dynamically change the evaluation function and adapt it to each terminal (list of parameters, triggers), rather than having a single (set of) evaluation function (s) for all terminals. As described, for instance, the evaluation function can be adapted to radio environment (vehicular, indoor), to service type (circuit-switched, packet-switched), or to application (WEB browsing, voice, video,...).

(iii) the invention can limit the transmission of measurement reports from the terminal. Therefore, it will limit terminal transmitted power, generated interference, and increase uplink capacity.

(iv) reduced complexity at the mobile terminal side is limited because it is likely that the downloaded evaluation function will use similar type of operations

(additions, multiplications, selection, sums, etc.) available anyway in conventional terminals.

(v) added complexity to download the evaluation function will in any case be masked by the increasing complexity (and functionalities) of terminals.

(vi) the invention can enable differentiation of network operators through their ability to properly define and use the flexibility provided by the download of evaluation functions.

Claims

Claims 1. A subscriber terminal including means for receiving an evaluation function, the evaluation function comprising a specification of operating parameters to measure, a calculation employing the measured parameters and providing an evaluation result, and a decision criterion specified in terms of the evaluation result; means for storing the evaluation function; and means for implementing the evaluation function by: determining which operating parameters to measure ; measuring the determined operating parameters; processing the measured parameter values to calculate an evaluation result ; comparing the calculated evaluation result with the criterion; responsive thereto, determining whether or not to transmit the measurement data and if the outcome is to transmit the measurement data, determining the content of the measurement data.
2. A subscriber terminal according to claim 1, wherein the evaluation function specifies that the content of the measurement data for transmission comprises the evaluation result.
3. A subscriber terminal according to claim 1 or 2, wherein the evaluation function specifies that the content of the measurement data for transmission comprises some or all of the measured parameter values.
4. A subscriber terminal according to any preceding claim, wherein the parameter values specified in the

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evaluation function include an interference level of signals received from a serving base station and received power levels from one or more neighbouring base stations.
5. A subscriber terminal according to any preceding claim, wherein the evaluation function is specified by a remote controller such that the subscriber terminal will transmit the measurement report when the parameter values are such that the controller will need to alter an aspect of a communication link or an operational instruction to the subscriber terminal.
6. A network controller comprising means for transmitting to a subscriber terminal an evaluation function, the evaluation function comprising a specification of operating parameters to measure, a calculation employing the measured parameters and providing an evaluation result, and a decision criterion specified in terms of the evaluation result, and an instruction to transmit measurement data.
7. A network controller according to claim 6 wherein the evaluation function specifies that measurement data for transmission comprises the evaluation result.
8. A network controller according to claim 6 or 7, wherein the evaluation function specifies that the content of the measurement data for transmission comprises some or all of the measured parameter values.
9. A network controller according to any of claims 6-8, wherein the parameter values specified in the evaluation function include an interface level of signals received

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by the subscriber terminal from a serving base station and received power levels from one or more neighbouring base stations.
10. A network controller according to any of claims 6- 9, wherein the evaluation function is specified such that the subscriber terminal will transmit the measurement report when the parameter values are such that the network controller will need to alter an aspect of a communication link or an operational instruction to the subscriber terminal.
11. A network controller according to any of claims 6- 10, and adapted to alter the evaluation function responsive to a condition of the subscriber terminal, responsive to one of the following set of conditions: (i) the radio environment, (ii) the type of service, (iii) the application.
12. A method of operating a communication system, the communication system including a subscriber terminal and a network controller including the steps of; in the network controller, providing and transmitting to the subscriber terminal an evaluation function, the evaluation function comprising a specification of operating parameters to measure, a calculation employing the measured parameters and providing an evaluation result, and a decision criterion specified in terms of the evaluation result; and in the subscriber terminal, receiving the evaluation function; storing the evaluation function; and implementing the evaluation function by:

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determining which operating parameters to measure; measuring the determined operating parameters; processing the measured parameter values to calculate an evaluation result ; comparing the calculated evaluation result with the criterion; responsive thereto, determining whether or not to transmit the measurement data to the network controller; and if the outcome is to transmit the measurement data, determining the content of the measurement data.
13. A storage medium storing processor-implementable instructions for controlling a processor to carry out the method of claim 12.
14. A communication system substantially as hereinbefore described with reference to the accompanying drawings.
15. A subscriber terminal substantially as hereinbefore described with reference to the accompanying drawings.