WO2001022757A1

WO2001022757A1 - Method of processing charging information

Info

Publication number: WO2001022757A1
Application number: PCT/FI2000/000801
Authority: WO
Inventors: Jukka Ranta; Otto-Aleksanteri Lehtinen; Seppo Rosnell; Harri Jokinen
Original assignee: Nokia Corporation
Priority date: 1999-09-21
Filing date: 2000-09-20
Publication date: 2001-03-29
Also published as: FI19992018A; AU7292800A

Abstract

The present invention relates to a mobile communication system comprising at least subscriber terminal A (MSA1, MSA2) and subscriber terminal B (MSB) which both comprise means for establishing a direct channel connection, and a mobile communication network comprising a billing unit (22). Subscriber terminal A (MSA1, MSA2) comprises means for collecting charging information during the direct channel connection and means for forwarding the collected information, and the billing unit (22) is arranged to receive the charging information transmitted by subscriber terminal A (MSA1, MSA2).

Description

METHOD OF PROCESSING CHARGING INFORMATION

BACKGROUND OF THE INVENTION

The invention relates to charging in a mobile communication system, and particularly to charging in a system wherein charging cannot be completely carried out controlled by a mobile communication network.

Operations known to a TETRA (Terrestrial Trunked Radio) system include, for example, a DMO (Direct Mode Operation) wherein mobile telephones communicate with each other on a direct channel without being switched by the base stations in a network. The TETRA is a digital PMR (Professional Mobile Radio) system, i.e. a trunking system which is typically used in business or official networks. All channels are then used by one or more business enterprises or official organizations and, when necessary, the system allocates free channels to the users from a common pool. In addition to their own subscriber numbers, subscribers in these networks have group numbers to enable calls meant for all subscribers in a group call group to be routed to the subscribers. The direct mode operation is a special mode of operation in the TETRA system and it may be activated by the subscriber himself or herself. The direct mode operation is useful when the mobile stations are located outside the coverage area of the network, when the network is out of order owing to a failure, for example, or when the network capacity is limited in the operation area or when, owing to concealment, for example, the direct connection is to be used. In the TETRA system, the coverage area of the direct mode operation is often extended by means of repeater stations.

A problem in the direct channel arrangement described above is that the network is unable to monitor the duration of the connections, for example. However, a charging opportunity may still be appreciated if, for example, the direct channel connections use the same licensed frequencies as the normal communication taking place through the network.

BRIEF DESCRIPTION OF THE INVENTION An object of the invention is to alleviate the above-mentioned problems and provide a solution which enables the charging systems to be used more extensively. This object is achieved with a method of the invention of processing charging information in a mobile communication system, the method comprising establishing a direct channel connection between sub- scriber terminal A and subscriber terminal B. The method of the invention is characterized by comprising the steps of: collecting and storing information necessary for charging in subscriber terminal A, and transmitting the charging information stored in subscriber terminal A to a billing unit in the mobile communication network. Charging information herein refers to all such information about a connection which a billing unit in a system is unable to collect by itself during a direct channel call but which it needs for charging, including starting and ending times of a connection and the subscriber number of a called party, for example. The subscriber number may be the subscriber number of a single sub- scriber or a group number and, when necessary, also this information on the type of the subscriber number may determine which tariff will be used. A connection refers to any communication taking place on a direct channel which may also comprise other components than speech, although the communication discussed herein by way of example is mainly speech calls. The invention also relates to a mobile communication system wherein the method of the invention can be utilized. The mobile communication system of the invention comprises at least subscriber terminal A and subscriber terminal B which both comprise means for establishing a direct channel connection, and a mobile communication network comprising a billing unit. The mobile communication system of the invention is characterized in that subscriber terminal A comprises means for collecting charging information during the direct channel connection and means for forwarding the collected information, and the billing unit is arranged to receive the charging information transmitted by subscriber terminal A. The invention further relates to a mobile station in a mobile communication network, which can be utilized in a mobile communication system of the invention. The mobile station of the invention comprises a transceiver arranged to transmit and receive radio signals on a direct channel to and from another mobile station. The mobile station of the invention is characterized by comprising means for generating charging information about the connection and a memory means for storing the charging information, and the transceiver is arranged to transmit the charging information to a billing unit in the network. The invention still further relates to a billing unit in a mobile communication network, which can be utilized in a mobile communication system of the invention. The billing unit in the mobile communication network of the invention is characterized by comprising means for receiving charging informa- tion from a subscriber terminal through the mobile communication network, and means for processing the charging information in order to bill the subscriber according to the charging information and price tariffs.

The idea underlying the invention is that by collecting charging in- formation locally in a subscriber terminal during a direct channel connection and by further transmitting this information later to a billing unit in the network, the charging system may also be applied to connections which do not actually use services of the network. If, for example, the parties to a direct channel call are located outside the coverage area of a network or the network is out of order, the charging information about the call still remains in the memory of the calling subscriber terminal until the subscriber terminal succeeds in establishing a connection to the network and transmitting the information to the billing unit. Next, the information can be stored in the network and it can be processed for the final billing as usual. The greatest advantage of the invention is that a network operator or a service provider may, if desired, use tariffs relating to direct channel connections, which it was unable to monitor using the prior art methods, and that this charging opportunity also relates to direct channel connections established outside the coverage area of the network. In a preferred embodiment of the invention, it is checked before establishing a direct channel connection that subscriber A has permission to establish the direct channel connection. Consequently, a SIM (Subscriber Identity Module) card, for example, may comprise conditions stored by the operator, and when these conditions are met the connection may be established. If, for example, subscriber terminal A is located in the coverage area of a network which does not allow roaming, subscriber terminal A is not given the permission necessary for establishing a direct channel connection. The procedure of granting permission is to prevent unauthorized use of a licensed frequency. In another preferred embodiment of the invention, the charging information is stored on the SIM card of subscriber terminal A several times during a call and finally after the call has been terminated. This is advantageous if, for example, the battery of subscriber terminal A has completely exhausted during the call, in which case the charging information that has not been stored might be lost completely. According to an embodiment of the invention, the charging information can be stored in subscriber terminal A after the call has ended until subscriber terminal A succeeds in transmitting the charging information to the billing unit of the network, or even after that. The charging information is stored in the memory after the call has ended in order to ensure that the information will be transmitted to the billing unit eventually even if the subscriber terminal were unable to establish a connection to the billing unit in the network when the call ends or the network were out of order at the particular time.

Preferred embodiments of the method, mobile communication sys- tem and mobile station of the invention are disclosed in the attached dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described in closer detail in connection with the preferred embodiments and with reference to the accompanying drawings, in which

Figure 1 is a flow diagram of a method of the invention;

Figure 2 is a block diagram of a mobile communication system of the invention; and

Figure 3 is a block diagram of a mobile station of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a flow diagram of a method of the invention. In step 1A, it is checked that subscriber A has permission to establish a direct channel connection. The permission may be based on conditions stored on the SIM card, and a connection may be established if these conditions are fulfilled. If the conditions are not satisfied, no connection will be established and the process proceeds directly to end step 1 H. If subscriber A has permission to establish a direct channel connection, the process proceeds to step 1 B wherein the direct channel connection between subscriber terminals A and B is established. During the direct channel connection, in step 1 C, charging in- formation, e.g. the starting and ending time of the connection and the subscriber number of the called subscriber, is collected in subscriber terminal A. In the next step 1 D, this charging information is stored on the SIM card of the subscriber terminal A, or, alternatively, in the memory of the mobile station. Storing may also take place several times during the direct channel connec- tion. In step 1 E, an attempt is made to transmit the charging information to the billing unit of the network. This may take place almost immediately after disconnecting the direct channel connection, for example. In step 1 F, it is checked whether or not the attempted transmission of the charging information was successful. If so, the process proceeds to step 1 G wherein the charging information is allowed to be removed from the SIM card. If, for some reason or other, the transmission of the charging information was unsuccessful, the process returns to step 1 E, i.e. another attempt is made to transmit the information to the billing unit of the network. Not until it is determined in step 1G that the transmission has succeeded can the process proceed to end step 1 H. As distinct from Figure 1 , the final storing of the charging information in the subscriber terminal may alternatively take place only when it has been determined that the first attempt to transmit the charging information was unsuccessful. In such a case, the subscriber terminal retains the charging information until the first transmission attempt only temporarily. After an unsuc- cessful transmission, repeated attempts are made to transmit the charging information from the memory to the billing unit of the network. The SIM card, for example, may comprise information stored by the operator on how often attempts at transmitting the charging information are made. Storing the charging information in the subscriber terminal, e.g. on the SIM card, after a successful transmission of the charging information may be based on the conditions stored on the SIM card by the operator, for example. Such an exemplary condition might be that no charging information will be removed from the SIM card before the memory is full. As distinct from Figure 1 , an alternative for transmitting the charging information to the billing unit of the network is to transmit the charging information repeatedly in smaller units when the direct channel connection is still in progress. If subscriber terminal A is outside the coverage area of the network during the connection and possibly also after the connection, a successful transmission of the charging information only takes place when subscriber terminal A enters the coverage area of the network the next time.

Figure 2 is a block diagram of a mobile communication system of the invention. The system of Figure 2 may utilize the embodiment disclosed in the flow diagram of Figure 1. The mobile communication network of the figure may be any cellular network which enables direct channel connections to be established between subscriber terminals. The mobile communication system disclosed comprises a base station BS whose coverage area is shown by a circle 21 , subscriber terminal A, i.e. a calling mobile station MSA1 , MSA2, subscriber terminal B, i.e. a called mobile station MSB, and a billing unit 22 of the network placed in connection with a mobile exchange DXT. The first location of the subscriber terminal A is shown in the figure by MSA1 and the sec- ond, later location by MSA2. The figure further shows a public switched telephone network PSTN and a subscriber terminal 23 connected thereto. The two-headed arrows in the figure designate a radio connection.

The mobile stations MSA1 and MSB in Figure 2 establish a direct channel call outside the coverage area 21. This is easily accomplished since the distance between the two mobile stations is short enough. During the call, subscriber terminal A generates and stores the charging information. When the call ends, subscriber terminal A MSA1 is unable to immediately establish a connection to the billing unit 22 of the network in order to transmit the charging information on the call because the mobile station MSA1 is not located in the coverage area 21. The mobile station MSA1 then stores the charging information on its SIM card, being compelled to try to transmit the charging information again later. When subscriber terminal A at the point designated by MSA2 later tries to transmit the charging information on the terminated call to the billing unit, this will succeed since MSA2 has then moved into the coverage area 21.

When located in the coverage area 21 of the base station BS, the mobile stations in Figure 2 may also make calls to the subscriber terminal 23 in the public switched telephone network PSTN.

Figure 3 shows a block diagram of a mobile station of the invention communicating on a direct channel. The mobile station of Figure 3 is similar to the mobile station MSA1 shown in Figure 2, for example. The figure only shows parts of the mobile station that are relevant to the invention. The mobile station disclosed comprises a transceiver 31 , a controller 33 and a SIM card 32. The transceiver 31 is arranged to transmit and receive on the channel used at a given time. The transceiver 31 is also connected to an antenna 34, which communicates with a radio path. The controller 33 is responsible for controlling the operation of the mobile station. It may, for example, receive signals associated with starting and ending a call supplied from the user interface, determine the channel to be used by the transceiver 31 , transmit and receive signalling messages through the transceiver 31 , and control the operation of the SIM card. The SIM card 31 comprises information necessary for identifying a subscriber and encrypting radio traffic. It is also responsible for generating and storing charging information, including starting and ending time of a call and the subscriber number to which the call was made, for example.

It is obvious to one skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not restricted to the above- described examples but they can vary within the scope of the claims.

Claims

1. A method of processing charging information in a mobile communication system, the method comprising establishing a direct channel connection between subscriber terminal A (MSA1, MSA2) and subscriber terminal B (MSB), characterized by comprising the following steps of: collecting and storing information necessary for charging in subscriber terminal A (MSA1, MSA2); and transmitting the charging information stored in subscriber terminal A (MSA1, MSA2) to a billing unit in the mobile communication network (22).

2. A method as claimed in claim 1, characterized by checking that subscriber A has permission to establish the direct channel connection on the basis of conditions on a SIM card (32) of subscriber terminal A (MSA1.MSA2).

3. A method as claimed in claim 1 or 2, characterized by storing the charging information on the connection on the SIM card (32) of subscriber terminal A (MSA1 , MSA2).

4. A method as claimed in any one of claims 1 to 3, character i z e d by storing the charging information in subscriber terminal A (MSA1, MSA2) at determined intervals during the connection and finally when the connection has been disconnected.

5. A method as claimed in any one of claims 1 to 4, characterized by storing the charging information in subscriber terminal A (MSA1, MSA2) after the connection has been disconnected, at least until the transmission of the charging information to the billing unit (22) has succeeded.

6. A mobile communication system comprising at least subscriber terminal A (MSA1, MSA2) and subscriber terminal B (MSB) which both comprise means for establishing a direct channel connection, and a mobile communication network comprising a billing unit (22), characterized in that subscriber terminal A (MSA1, MSA2) comprises means for collecting charging information during the direct channel connection, and means for forwarding the collected information, and the billing unit (22) is arranged to receive the charging information transmitted by subscriber terminal A (MSA1, MSA2).

7. A mobile communication system as claimed in claim 6, characterized in that subscriber terminal A (MSA1 , MSA2) comprises means for establishing a connection through a mobile communication network to a subscriber terminal (23) in a public switched telephone network (PSTN).

8. A mobile station in a mobile communication network, the mobile station comprising a transceiver (31) arranged to transmit and receive radio signals on a direct channel to and from another mobile station, characterized by comprising means (32) for generating charging information about the connection and a memory means (32) for storing the charging information, and the transceiver (31) is arranged to transmit the charging information to a billing unit (22) in the network.

9. A mobile station as claimed in claim 8, characterized by comprising a SIM card (32) generating and storing the charging information.

10. A mobile station as claimed in claim 8 or 9, characterize d in that the means for generating the charging information comprise a clock for measuring the duration of the connection.

11. A billing unit in a mobile communication network, characterized in that the billing unit (22) comprises means for receiving charging information from a subscriber terminal through a mobile communication network, and means for processing the charging information in order to bill the subscriber according to the charging information and price tariffs.