AU715657B2

AU715657B2 - Method and device for optimising a mobile radio network

Info

Publication number: AU715657B2
Application number: AU20078/97A
Authority: AU
Inventors: Ralf Collmann
Original assignee: Alcatel CIT SA; Alcatel SA
Current assignee: Alcatel Lucent SAS
Priority date: 1996-05-11
Filing date: 1997-05-07
Publication date: 2000-02-10
Anticipated expiration: 2017-05-07
Also published as: AU2007897A; EP0806880A3; DE19619205A1; EP0806880A2

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990 0 0* 9 0.

S..0 0 0 0::0.

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: METHOD AND DEVICE FOR OPTIMISING A MOBILE RADIO

NETWORK"

The following statement is a full description of this invention, including the best method of performing it known to us:- 2 The invention relates to a method of optimising an operating mobile radio network.

From WO 92/21182 a method is known for optimising a mobile radio network which is in service, together with a device intended for this. According to that method, it is determined whether an error exists in the network ("malfunctions and alarms", page 12, lines 17-20), by monitoring the mobile radio network with an operations and maintenance centre ("administrative centre 200", page 13, lines 26 ff). If an error occurs, actual data ("cell parameters") is retrieved from the mobile radio network in order to calculate nominal data ("set of proposed changes") for optimising the parameter settings in the mobile radio network (see Patent Claim 1 there, as well as the description for Figure The device for carrying out this method is the operations and maintenance centre itself (see page 13 there, lines 26 ff).

"An object of the iivention is to improve the just-mentioned method, so that it can be carried out in a device which is particularly suitable for the calculation of the S" 15 nominal data from the actual data and which preferably requires no computer capacity from the opera-ions and maintenance centre.

According to the invention, there is provided TEXT iOF:::C LAIM 1.

With this invention a device actually provided for network planning is used to optimise an operating mobile radio network. Thus the optimisation becomes very simple. Moreover, a fully automatic optimisation of the mobile radio network becomes possible by constructing a control loop which includes the device and the operations and maintenance centre.

In order that the invention may be readily carried into effect, an embodiment thereof will now be described in relation to the accompanying drawings, in which: Figure 1, shows schematically the construction of a control loop for the optimisation; Figure 2, shows schematically the construction of a radio control loop; Figure 3, is a block diagram of the device; and Figure 4, is a flow chart for the method.

Figure 1 shows schematically a control loop for optimising an operating mobile radio network MRN. The control loop consists essentially of a computer-controlled device NPT which corresponds to a so-called "Network Planning Tool" and an 3 operations and maintenance centre OMC. An input I of the device NPT is connected to the operations and maintenance centre OMC. An output 2 of the device NPT is connected to an input of the operations and maintenance centre OMC. Also, a connection for the transmission of control signals CTR leads from the operations and maintenance centre OMC to the device. In this example the operations and maintenance centre OMC is connected to a mobile radio exchange MSC and to a radio base station control unit BSC. The mobile radio network generally contains several mobile radio exchanges and radio base station control units. The mobile radio exchange MSC, the radio base station control unit BSC connected to it and the radio base stations BTS form components of the mobile radio network MRN, which here is a mobile radio network in accordance with the GSM standard. The connection between the mobile radio exchange and the radio base station control unit is an X.25 link AIF.

"The radio base station control unit controls several of the radio base stations and is o connected to these via a PCM-30 link ABIF. The link AIF is also referred to briefly as an A-interface, the link ABIF as an ABIS-interface, corresponding to the nomenclature defined in the GSM standard.

In order to monitor the signalling and data traffic on these interfaces, measuring devices are provided there which are connected via a switching matrix to network analysis evaluation units ANL1 to ANLn. These evaluation units are here protocol analysers which analyse the data transmission over the interfaces AIF and ABIF mentioned with the different prescribed protocols MAP, ISUP, LAPD). If errors occur during the data transmission over the interfaces mentioned, they are detected by means of these analysers. The analysers ANL1 to ANLn produce actual data, i.e. measured data for the data transmission, which is applied as input data DIN via a connection to Input 1 of the device NPT. The operations and maintenance centre OMC also produces input data DIN and applies this to the device NPT. The input data produced by the operations and maintenance centre OMC essentially relates to the actual state of the components mentioned, MSG, BSC and BTS. Input data is produced, among others, from operating data which indicates the current traffic load, the number of blocked radio channel ports or the number of access requests.

In addition, a database DBX is shown in Figure 1 which is connected to the input of the device NPT ,nd also transmits input data. The database DBX shown is a customer database in which incoming subscriber complaints are stored by the mobile radio network operator.

The mobile radio network shown in Figure 1, with the control loop described earlier, operates according to the following method whose flow chart is shown in Figure 4 (Figure 1 and Figure 4 are considered together in the following).

In the process 100 the operations and maintenance centre OMC first monitors the operation of the network by, among other things, detecting errors in the data transmission over the interfaces AIF and ABIF through control of the analysers ANL1 to ANLn. The operations and maintenance centre OMC is also able to detect errors in the components MSC, BSC and BTS. In addition, the operations and maintenance centre OMC is connected to the database DBX (not shown) in order to evaluate customer complaints stored there (step 110).

e In a second step 120 it is established whether an error in the network has occurred. If this is not the case, no changes are made in step 121. If, however, it is the case, then the input data for the device NPT is determined in step 130. The content of this input data provides information about the network monitoring, especially about *errors in the components mentioned or in the data transmission over the interfaces mentioned. The input data DIN also includes data from the customer database DBX.

If now the input data DIN is applied to the input of the device NPT, the operations and maintenance centre 0MC, by means of a control signal CTR, initiates the calculation within the device NPT of output data from this input data. It is also possible for the calculation of the output data to be initiated by the transmission of the input data itself, i.e. without the control signal CTR. In a step 140 the output data DOUT is calculated using a function which reflects the radio network model (e.g.

according to WALFISH and IKEGAMI) of the mobile radio network MRN. Variables of this function are, among others, the input data DIN and planning data DNW for the network. For the formation of a radio network model, systems of nonlinear equations are generally required. [he representation in Figure 4 of the function f(DIN, DNW) is here only a schematic representation of such a system of equations. The device NPT calculates output data DOUT, using the input data DIN and the planning data DNW for the network. For this the device NPT contains a neuron network with learning capability which, before the calculation, is prepared by the input of so-called training sequences, i.e. it is calibrated for the mobile radio network MRN.

In step 150 a check is now made to test whether the calculated output data DOUT differs from the planning data DNW. If this is the case, the planning data DNW is corrected in step 151 by being set equal to the output data DOUT. If the calculated output data DOUT only differs slightly from the planning data DNW, then in step 160 the parameter settings are changed by means of the calculated output data.

Correction of the parameter settings here is understood to mean the following measures: Correction of settings in the components MSC, BSC and BTS, such as so-called "frequency redefinition" with BSC, or "power ramping" with BTS. These measures essentially relate to software parameters and, for the most part, can be carried out by the operations and maintenance centre OMC via control commands in the network. In addition, correction of parameter settings is also understood to mean measures applied to the hardware HW in the network MRN. The alterations to hardware HW of the mobile radio network are essentially carried out in the field. This may include, for example, the installation and adjustment of sector antennas or the provision of additional radio carriers. If in step 160 the required parameter settings have been altered by means of the calculated output data, then the optimisation of the network has been achieved. The method of Figure 4 can be carried out continuously by following step 160 with step 110 (not shown).

~The method according to the invention, as described above with the aid of Figure 1 and Figure 4 is very easily accomplished since the control loop described only needs to be constructed by means of essentially known devices (NPT and OMC).

According to the invention the device NPT, which basically serves for network planning, is here used for the optimisation of the operating mobile radio network.

Figure 2 shows a mobile radio network MRN' in which a control loop is constructed by means of radio links between the operations and maintenance centre OMC and the device NPT.

Thus the operations and maintenance centre OMC, as well as the device NPT, each contain a transmitter TX and a receiver RX. The operations and maintenance centre and the device are connected by radio via the interfaces DL and UL. The analysers ANL1 and the customer database DBX are also connected via radio with the device NPT. The control loop in Figure 2 operates according to the already-described method (see Figure i.e. the operations and maintenance centre OMC, the analysers ANL1 and the database DBX provide input data for the device NPT. From the input data, by means of the network model function described earlier, output data is calculated which the device NPT transmits to the operations and maintenance centre, as well as to devices for altering the hardware HW. Figure 2 also shows a mobile device MON for monitoring network functions, in particular the monitoring of field coverage. This mobile device MON also supplies input data to the device NPT.

Figure 3 shows a block diagram which is intended to explain the schematic arrangement of the device NPT. The device NPT (Network Planning Tool) is a device controlled by a processor PROC. The processor PROC is connected via a data and signalling bus BUS with the following components: an input data interface IFI, an interface for input/output devices IFT, a data converter CON, a circuit NNW, a database DB and an output data interface circuit IFO.

Via the input data interface IFI, the device NPT receives the input data DIN which is preferably structured according to the X.25 protocol. If the input data DIN is structured according to a different protocol, it is converted to the X.25 protocol by the data converter CON.

The input data DIN essentially represents measuring data which reflects the actual state of the mobile radio network. From the input data DIN, the output data DOUT for parameter setting is then calculated. For this, the processor PROC controls the circuit NNW which is a neuron network with learning capability. The input data DIN, and the planning data DNW retrieved from the database DB, are combined in the circuit NNW corresponding to the function f(DIN, DNW) described earlier in order to calculate the output data DOUT. Via the output data interface IFO, the output data DOUT is transmitted to the operations and maintenance centre and, if required, to other devices for the setting of software and hardware parameters in the mobile radio network.

The invention was described with the example of a public mobile radio network constructed according to the GSM standard. However, other design examples can be considered, such as the use of the invention in a private mobile radio network, e.g.

according to the TETRA standard, or its use in a universal mobile radio network, the so-called UMTS (Universal Mobile Telecommunication System).

Claims

1. A method of optimising an operating mobile radio network, comprising the steps of: determining whether an error occurs in the mobile radio network by monitoring the mobile radio network by means of an operations and maintenance centre; and if an error occurs, retrieving actual data from the mobile radio network to calculate nominal data for optimising parameter settings in the mobile radio network, wherein the actual data are input data for a computer-controlled network planning device which are determined by means of measuring devices, and wherein the nominal data are output data from the computer-controlled network planning device which are calculated by the latter from the input data S and from planning data specified in accordance with a radio network ~model.

2. A method as claimed in claim 1, wherein the input data are transmitted from the measuring devices directly or via the operations and maintenance centre to the computer-controlled network planning device.

3. A method as claimed in claim 1, wherein the planning data are compared with the output data to determine whether they have to be corrected.

4. A method as claimed in claim 2, wherein parameter settings in the mobile radio network are corrected by means of the output data if the output data differ from the planning data by more than a predeterminable measure.

A method as claimed in claim 4, wherein the parameter settings relate to software and/or hardware parameters.

6. A method as claimed in claim 4, wherein the sequence of steps from the monitoring of the mobile radio network to the correction of the parameter settings is repeated until the output data differ from the planning data by less than the predeterminable measure.

7. A device for optimising an operating mobile radio network by means of an operations and maintenance centre which monitors the mobile radio network and determines whether an error occurs in order to then retrieve actual data from the mobile radio network from which the device calculates nominal data for optimising parameter settings in the mobile radio network, wherein the device is a computer-controlled network planning device, and wherein the actual data are input data for the computer-controlled network planning device which are determined by means of measuring devices, and wherein the nominal data are output data from the computer-controlled network planning device which are calculated by the latter from the input data and from planning data specified in accordance with a radio network model.

8. A method substantially as herein described with reference to Figures 1 4 of the accompanying drawings. A device substantially as herein described with reference to Figures 1 4 of the accompanying drawings. DATED THIS SECOND DAY OF MAY 1997 ALCATEL ASTI IO"m em-PAGNIL"'' r',LE ^R 'El E _1r'TRICIT1