Description of Related Art Operation and maintenance of telecommunications units are frequently performed actions in a telecommunications system. US Patent 5,297,193 shows how mainte- nance of a mobile telecommunications network is carried out by means of a cen- trally located operation and maintenance (O&M) centre. The disadvantage of this solution is that the O&M centre only has the capacity to handle operations of a gen- eral character while there is often a need to carry out more specific O&M actions intended for a particular telecommunications unit in the system, for example at start- up of the telecommunications unit.

US Patent US 5,448,616 describes a method and an apparatus in a mobile telecom- munications system for automatically measuring the Bit Error Rate (BER) of a par- ticular telecommunications unit. This is done by a built-in BER test device in the telecommunications system. The apparatus in incorporated in an analogue channel unit in the base station to be tested. According to this US Patent the incorporated BER test device enables BER tests and the remote control of BER tests from an O&M centre. A disadvantage of the solution according to US 5,448,616 is that each test object has to be provided with extra equipment, which implies an additional cost. The extra equipment is often installed at an initial stage, which causes another disadvantage, in that only the tests for which the equipment was intended at the ini- tial stage can be carried out. This reduces the flexibility of O&M. A solution to this problem is to go out to each telecommunications unit and carry out tests by means of a physical link between the telecommunications unit and a test instrument. This

may, however, cause problems if the telecommunications unit is found in a place which it is difficult to get to. Normally, costly equipment has to be transported to the place in which the telecommunications unit is found, and connected. As a result of this, in addition to expensive maintenance, the periods between maintenance tend to be long. Another solution would be to connect the O&M terminal to a radio unit, or alternatively to an IR unit, and transfer service commands to the telecommunica- tions unit by means of radio signals or IR signals. This solution would, however, re- quire functions for establishing connections in each test object, which would incur to great additional costs.

Summary of the Invention The present invention deals with the problem of performing high quality flexible special service of telecommunications units at a low cost, especially when the units are found in places to which it is hard to get.

In accordance with this, a problem that is dealt with is the problem of establishing, without the requirement of a physical connection, a connection for special tests be- tween an O&M terminal and a selected telecommunications unit, a so called, test object, without the need of going to the location of the test object.

According to the invention this problem is solved by providing a service port in the telecommunications system, that is able to establish a connection to the selected test object as well as the O&M terminal, irrespective of the location of the test object and the O&M terminal, respectively, in the telecommunications system.

According to the invention this is achieved by establishing a connection between the O&M terminal and the service port. The connection is established in accordance with a so called first signalling protocol intended for the signalling between the O&M terminal and the service port. The service port then establishes a connection to the selected test object. The connection is established in accordance with a so

called second signalling protocol intended for the signalling between the O&M ter- minal and the test object. The service port, according to the invention, converts service commands from the O&M terminal to the telecommunications unit and the other way around. The conversion is made from the first signalling protocol to the second signalling protocol and the other way around.

A purpose of the present invention is to transport service commands and other data from the O&M terminal to a selected test object and vice versa without establishing a physical connection between the O&M terminal and the test object.

Another purpose of the invention is to offer flexible special service of high quality to a test object without the need to install test equipment in the test object.

Yet another purpose of the invention is to let a connection centre common to the test objects handle the establishment of connections between the O&M terminal and a selected test object.

An advantage of the invention is that the high quality flexible special service of a test object in a telecommunications system can be offered at a low cost.

Another advantage of the invention is that service may be performed for several dif- ferent test objects without the need to provide each test object with extra equipment.

The invention will now be described in more detail by way of preferred embodi- ments and with reference to the enclosed drawings.

Brief Description of the Drawings Figure 1 is a block diagram of a telecommunications system in which an external service port has been provided.

Figure 2 is a flow chart of an inventive method. The method is carried out by means of the configuration shown in Figure 1.

Figure 3 is a block diagram of a telecommunications system comprising an internal service port.

Figure 4 is a flow chart of an inventive method. The method is carried out by means of the configuration shown in Figure 3.

Figure 5 is a block diagram of an inventive apparatus.

Preferred Embodiments An embodiment of the inventive method for the remote maintenance of a Radio Base Station (RBS) RBS 1 will now be described. In Figure 1 a telecommunications system TS is shown. The telecommunications system comprises a mobile switching centre MSC connected to a terrestrial public services telephone network PSTN. A base station controller BSC is connected to the MSC and the RBS RBS 1 is con- nected to the base station controller BSC. The mobile switching centre MSC, the base station controller BSC and the radio base station RBS are all in this embodi- ment part of a GSM system. A service port WROG is, in this embodiment, con- nected between the terrestrial network PSTN and the base station controller BSC.

The service port communicates through the PSTN network with a so called first sig- nalling protocol SP 1, which is a standardized GSM protocol that is well defined in the ETSI GSM Technical Specification. The GSM protocol has a transmission rate of 9.6 kbit/s. The service port also communicates with the base station controller BSC by means of a so called second signalling protocol SP2, which is a standard- ized transmission protocol that is well defined in ANSI T1.403 and ITU-T recom- mendations G.703. The transmission protocol has a transmission rate of either 1544 kbit/s (1.5Mbit) or 2048 kbit/s (2Mbit) divided into time slots of 64 kbit/s. In the 1.5

Mbit case there are 24 time slots and in the 2 Mbit case there are 32 time slots of 64 kbit/s. The service port WROG can convert incoming signals to the service port from the PSTN network in accordance with the first 9.6 kbit/s signalling protocol SP1 to signals intended for the second 64 kbit/s signalling protocol SP2. Commands and other data are then translated from 9.6 kbit/s format to 64 kbit/s format. Com- mands are transmitted after conversion from the service port WROG to the base station controller BSC. The service port WROG also converts signals in the oppo- site direction, that is, incoming signals from the base station controller are converted to signals having a suitable format for the PSTN network. This bi-directional con- version technique is known in the art. According to the inventive method the service port WROG also carries out a security check. This security check will be described in more detail below. Figure 1 shows an o&M terminal OMT1. The O&M terminal in this embodiment is a portable personal computer. The O&M terminal is normally used for operation and maintenance of the radio base station RBS 1. This has been achieved according to prior art by connecting the O&M terminal to the base station by means of a physical connection. The O&M terminal OMT1, however, according to the embodiment is connected to a mobile telephone MS and the mobile telephone is arranged to communicate with the radio base station RBS1 by means of radio sig- nals. These radio signals in Figure 1 are shown as a flash shaped symbol between the radio base station and the antenna of the mobile telephone.

In the following the inventive method will be described in more detail. The method is a method of performing operation and maintenance of the radio base station RBS1, and more specifically a method of reading error statistics. As a first step in the method according to this embodiment the above mentioned service port WROG has been connected between the PSTN network and the base station controller.

Also, the O&M terminal OMT1 has been connected to the mobile telephone MS.

The method after this comprises the following additional steps:

- A user ofthe O&M terminal OMT1 decides to perform operation or maintenance of one or more telecommunications units in the telecommunications system.

- A connection SP1 is established, at the request of the user, between the O&M terminal OMT1 and the service port WROG. The connection is established by the user stating the connection number of the service port by means of the keyboard of the O&M terminal. On the established connection SP 1 messages are trans- ported according to the above mentioned standardized GSM protocol with a transmission rate of 9.6 kbit/s.

- An authorization request 1 is transmitted on the established connection from the service port WROG through the PSTN network, the mobile switching centre MSC, the base station controller BSC, the radio base station RBS 1 and the radio interface, to the O&M terminal OMT 1. In the authorization request 1 user spe- cific parameters are requested. The parameters are needed for the authorization of the user.

- The requested parameters, for example, a password, are given by the user and transmitted in a parameter message 2 to the service port WROG. The parameters for authorization are analyzed in the service port WROG. This authorization can include additional parameter requests and answers. The authorization is well known in the art and will not be described in more detail. after the authorization has been successfully completed an acceptance message 3 is transmitted from the service port WROG back to the O&M terminal OMT1.

- The acceptance message 3 is received in the O&M terminal OMT1 and the mes- sage that the authority has been allowed is presented to the user.

- The user selects the radio base station RBS 1 as the object to be handled. The user defines the base station RBS1 by pressing keys on the keyboard ofthe O&M terminal.

- A connection command 4 is transmitted from the O&M terminal OMT1 to the service port WROG. The connection command comprises information about to which one of the telecommunications units in the telecommunications systems a connection is requested, that is, in this case, the base station RBS 1.

- The service port WROG receives a request for a connection to the base station RBS 1 and a connection SP2 is established between the service port WROG and the base station RBS 1. The established connection is of the standardized trans- mission protocol mentioned above, with a transmission rate of 64 kbit/s.

- When the connection has been established a connection message 5 is transmitted from the service port WROG to the O&M terminal OMTI. The message is pre- sented to the user in the O&M terminal OMT1.

- The user decides to read error statistics for the base station RBS 1 specified above. The user of the O&M terminal specifies this wish by pressing keys.

- A service command 6 is transmitted from the O&M terminal OMT1 to the serv- ice port WROG.

- The service command 6 is converted from the transmission rate 9.6 kbit/s to a transmission rate of 64 kbit/s.

- The service command is forwarded from the service port WROG through the base station controller to the base station RBS 1.

- The service command is received in the base station and the desired error statis- tics 7 is read from the base station RBS 1 to the service port WROG.

- The error statistics 7 is converted from the transmission rate 64 kbit/s to a trans- mission rate of 9.6 kbit/s.

- The error statistics is forwarded from the service port WROG through the PSTN network, the mobile switching centre MSC, the base station controller BSC and the radio base station RBS1, to the O&M terminal OMTI.

- The error statistics is presented to the user in the O&M terminal OMT1.

In the embodiment described above the radio base station RBS 1 has been pointed out as the telecommunications unit in which the user wants to perform actions. This choice is only to be seen as an example and it would also be possible to use other units in the telecommunications system as test objects, for example the mobile switching centre MSC or the base station controller BSC. The fact that the base sta- tion used for the establishment of the connection between the O&M terminal and the service port, that is RBS1, constitutes the test object is also insignificant to the inventive idea. Any one of the test objects found in the telecommunications system could constitute the selected test object.

According to the embodiment described above the delivery of error statistics has been requested by the user. It is also possible to perform other O&M commands, for example the monitoring of preset values or a common analysis of the state of a test object.

Figure 2 is a flow chart of the inventive method. The most important steps of the in- vention are shown in the Figure. Abbreviations used in the Figure are considered to

have been explained above. The method is carried out in accordance with Figure 2 and in accordance with the brief explanation of the Figure given below.

- The service port WROG is connected between the PSTN network and the base station controller BSC and is connected to the O&M terminal OMTl to the mo- bile telephone MS 1, according to a block 101.

- The connection SP 1 is established on request of the user between the O&M ter- minal OMT1 and the service port WROG, according to a block 102.

- An authorization request 1 is transmitted on the established connection from the service port WROG to the O&M terminal OMT1, according to a block 103.

- The requested parameters are entered by the user and transmitted in the parameter message 2 to the service port WROG, according to a block 104.

- When the authorization has been successfully completed the acceptance message 3 is transmitted from the service port WROG back to the O&M terminal OMT1, according to a block 105.

- The user selects the base station RBS1 as the object to be handled, according to a block 106.

- The connection command 4 is transmitted from the O&M terminal OMT1 to the service port WROG, according to a block 107.

- The connection SP2 is established between the service port WROG and the base station RBS1, according to a block 108.

- The user decides to read the error statistics for the base station RBS 1 specified above, and the service command 6 is transmitted from the O&M terminal OMT1 to the service port WROG, according to a block 109.

- The service command 6 is converted from the transmission rate 9.6 kbit/s to a transmission rate of 64 kbit/s, according to a block, and the service command is forwarded from the service port WROG through the base station controller BSC to the base station RBS1, according to a block 110.

- The requested error statistics 7 is read from the base station RBS 1 to the service port WROG, according to a block 111.

- The error statistics 7 is converted from the transmission rate 64 kbit/s to the transmission rate 9.6 kbit/s, according to a block 112.

- The error statistics is presented to the user in the O&M terminal OMT1, accord- ingtoablock 113.

Figure 3 shows an alternative to the embodiment shown above in connection with Figure 1. The purpose of the embodiment shown in Figure 3 is, among other things, to show that the inventive idea can be kept even if the telecommunications system is modified. Figure 3 shows parts of the telecommunications system shown above. The telecommunications system comprises the mobile switching centre, connected to the terrestrial telephone network PSTN. The base station controller, as before, is con- nected to the mobile switching centre MSC. A service port IWROG is in this em- bodiment found in the mobile switching centre MSC. The internal service port, indi- cated in Figure 3 as a dotted line, is implemented in software in the mobile switch- ing centre MSC. The service port IWROG communicates, as before, through the PSTN network, with the first signalling protocol SP 1 having a transmission rate of 9.6 kbit/s. The service port also communicates with the base station controller BSC

by means of the second signalling protocol SP2 having a transmission rate of 64 kbit/s. The internal service port IWROG has the same function as described above, that is, the service port converts incoming signals to the service port from an o&M terminal OMT2, through the PSTN network in accordance with the first signalling protocol, to signals intended for the second signalling protocol SP2. The service port IWROG also converts signals in the opposite direction, that is, signals from the base station controller BSC to the O&M terminal OMT2. The O&M terminal OMT2, which is in this embodiment intended for the setting of parameters in the base sta- tion controller BSC, has been connected by a modem (not shown in Figure 3) to the PSTN network.

In the immediately following the inventive method according to the alternative em- bodiment will be described. The method is a method of performing operation and maintenance of the base station controller BSC, and more specifically a method of setting parameters in the base station controller. The method comprises the follow- ing steps: - A user of the O&M terminal OMT2 decides to perform operation or maintenance of telecommunications units in the telecommunications system.

- A connection SP 1 is established, at the request of the user, between the O&M terminal OMT2 and the service port IWROG. The connection is established by the user stating the connection number of the service port by means of the key- board of the O&M terminal. The established connection has a transmission rate of 9.6 kbit/s.

- The user selects the base station controller BSC as the object to be handled.

- A connection command 11 is transmitted from the O&M terminal OMT2 to the service port IWROG. The connection command comprises information about to

which one of the telecommunications units in the telecommunications systems connection is requested, that is, in this case, the base station controller BSC.

- The service port IWROG receives a request for a connection to the base station controller BSC and a connection SP2 is established between the service port IWROG and the base station controller BSC. The established connection is the standardized transmission protocol mentioned above, with a transmission rate of 64 kbit/s.

- When the connection SP2 has been established a connection message 12 is transmitted from the service port IWROG to the O&M terminal OMT2. The mes- sage is presented to the user.

- The user decides to set parameters for the base station controller BSC. The user of the O&M terminal OMT2 specifies, by pressing keys, the parameters to be set and the new values for these parameters in a monitor in the O&M terminal OMT2.

- A modify command 13 is transmitted from the O&M terminal OMT2 to the service port IWROG.

- The modify command 13 comprising the desired parameters is converted from the transmission rate 9.6 kbit/s to a transmission rate of 64 kbit/s.

- The service command is forwarded from the service port IWROG to the base sta- tion controller BSC.

- The parameters defined in the modify command are modified in the base station controller according to the specified request.

- A result message 14 is transmitted from the base station controller through the internal service port IWROG and the PSTN network to the O&M terminal OMT2. Conversion is made in the service port IWROG from the transmission rate 64 kbit/s to a transmission rate of 9.6 kbit/s.

- The resulting parameter setting is presented to the user.

Figure 4 is a flow chart of the described method. The most important steps to the in- vention are shown in the Figure. Abbreviations used in the Figure are considered to have been explained above. The method is carried out in accordance with Figure 4 and in accordance with the brief explanation of the Figure given below.

- The user of the O&M terminal OMT2 decides to perform operation or mainte- nance of telecommunications units in the telecommunications system, according to a block 201.

- The connection SP1 is established on request of the user between the O&M ter- minal OMT2 and the service port IWROG in the mobile switching centre MSC, according to a block 202.

- The user selects to handle the base station controller BSC, according to a block 203.

- The connection command 11 is transmitted from the O&M terminal OMT2 to the service port IWROG, according to a block 204.

- The connection SP2 is established between the service port IWROG and the base station controller BSC, according to a block 205.

- The connect message 12 is transmitted from the service port IWROG to the O&M terminal OMT2 and is presented to the user, according to a block 206.

- The user of the O&M terminal OMT2 defines, by pressing keys, the parameters to be set and their new values, according to a block 207.

- The modify command 13 is transmitted from the O&M terminal OMT2 to the service port IWROG, according to a block 208.

- The modify command 13 is converted from the transmission rate 9.6 kbit/s to a transmission rate of 64 kbit/s, according to a block 209.

- The parameters defined in the modify command are modified in the base station controller BSC, according to a block 210.

- The result message 14 is transmitted from the base station controller through the internal service port IWROG and the terrestrial network PSTN to the O&M ter- minal OMT2, according to a block 211. Conversion is made in the service port IWROG from 64 kbitls to 9.6 kbit/s.

- The resulting parameter setting is presented to the user, according to a block 212.

Figure 5 shows, yet another embodiment of an inventive apparatus for carrying out the inventive methods shown above. The apparatus comprises an O&M terminal 40 comprising a modem 41. The modem 41 is connected through a first telecommuni- cations connection 70 to a modem 51 in a service port 50. The service port 50 also comprises yet another modem 52 which is connected to a test object 60 through a second telecommunications connection 80. The modem 41, the first telecommuni- cations connection 70 and the modem 51 all constitute means for establishing a connection between the O&M terminal and the service port in accordance with the

above mentioned first signalling protocol SP 1 specified above, between the terminal 40 and the port 50. The modem 52 and the second telecommunications connection 80 constitute means for establishing a connection between the service port 50 and the test object 60 in accordance with the above mentioned second signalling proto- col SP2, specified above. The service port 50 also comprises means 55 for selecting a test object specified by the user, in this case the test object 60. The service port also comprises means 56 for exchanging service parameters between the O&M ter- minal 40 and the selected test object 60 and means 57 for converting signals be- tween the two signalling protocols SP1, SP2.

In the embodiments described in this document two different signalling protocols SP 1 and SP2 have been specified. Other protocols than these two could also be used. The above mentioned 9.6 kbit/s standardized GSM protocol could be replaced, for example, by the GSM standard General Packet Radio Service (GPRS). Alterna- tively the GSM protocol could be exchanged for the High Speed Circuit Switched Data (HSCSD) protocol for several data channels. It is also possible to let the stan- dardized 64 kbit/s transmission protocol be shared with other units in the telecom- munications network, for example, for signalling in another form to and from base stations, to and from base station controllers, so that instead of the above mentioned transmission rate of 64 kbit/s a transmission rate of 32 kbit/s is achieved.

In the embodiments a GSM system has been used as a part of the telecommunica- tions system, but here as well other telecommunications systems could be used without affecting the inventive idea. It should also be noted that the mutual order of the method steps shown above could be changed within the scope of the invention.

Thus, the invention is not limited to the embodiments described above and shown in the drawings, but can be modified within the scope of the appended claims.