SE470503B - Ways and means of activity monitoring in a mobile telephone network - Google Patents

Description

2 mobile, a procedure called IMSI-detach has been introduced in GSM.

IMSI-detach means that the mobile notifies the network if the power is switched off.

The network now makes a mark in the current mobile telephone station, MSC / VLR (Mobile Services Switching Center / Visitor Location Register) in GSM, for the current subscriber. In the subsequent terminating leash, paging is not performed, which means that radio capacity is saved in this way.

However, the IMSI-detach method has its weaknesses. First, the message to the network from the mobile, ie the IMSI detach procedure, that the power has just been switched off may fail, e.g. due to the message not reaching the network. The mobile phone can also end up in radio shadow, which means that it cannot communicate with the network.

These weaknesses mean that later paging attempts will always fail. The radio network has then been unnecessarily loaded.

A very important function in each MSC / VLR is therefore so-called activity monitoring (English. Implicit Detach). Activity monitoring means that the network, despite not having received an IMSI detach message from the mobile phone, assumes that the mobile phone is most likely turned off.

This is generally done in such a way that after a certain period of time has elapsed since the last radio contact with a mobile phone, it is considered that the mobile phone is no longer switched on. However, this method in turn requires that the mobile, after a certain time interval, notifies the network that it is switched on even if it does not move to a new position area. Periodic location updating is specified in the GSM recommendations.

For activity monitoring to work properly, the time for periodic location updating must be less than the time for activity monitoring, ie the time when it is considered that the mobile is no longer switched on.

In previous systems, activity monitoring has been implemented in such a way that for each subscriber in the current MSC / VLR, there is a continuous time monitoring that is restarted at each radio contact with the mobile phone. If this time monitoring triggers, the mobile phone is considered to be switched off, and paging is therefore not done for a terminating leash that is set up after the time tripping. The time for this activity monitoring is set by the MSC operator and can vary between, for example, 15 minutes and a number of hours.

The solution described above causes a significant base load 3 in the system. This is because each individual time monitor requires processing power, and each subscriber in an MSC has such a time monitor running continuously (except those that have already been turned off or are considered to be due to the time monitor being triggered). An MSC / VLR can have over 100,000 subscribers registered at the same time. GB 2 244 409 describes a mobile radio system in which the mobiles are switched on periodically with the intention of updating the location of the mobile at the base. Each mobile has a timer for the periodic initiation of communication with the base station. The system can store details regarding the last registration of a mobile, including the time of the last registration and the period between the registrations. On this basis, the system can decide on how messages to the mobile should be delivered appropriately. With the help of the time registrations, you can thus determine when it is possible to get in touch with the mobile phone.

EP 102 129 describes a radio communication system where a mobile receiver can communicate with at least one transmitter. The transmitters transmit on a plurality of channels and the receiver includes a tuner which can scan the channels. Each transmitter periodically transmits a signal on its transmitter channel. The receiver comprises a timer for activating the scanner when such a signal has not been received on the channel to which the receiver is tuned, for a predetermined time, which is not less than the time period of said channel signals, and for deactivating the scanner when such a signal is received on the channel to which the receiver is tuned.

Disclosure of the invention.

The object of the invention is to eliminate a new method and device for eliminating disadvantages of the above-mentioned type in order to determine that the time since the last radio contact is so long that the mobile phone can be considered to be switched off.

This object has been achieved by registering in the method according to the invention the time of each radio contact with a mobile and in the event of the occurrence of a terminating pair, the difference between the time of its occurrence and the said registered time is calculated, the mobile being marked as this difference exceeds a certain time.

The device according to the invention is characterized in that in mobile telephone stations, which are included in the network, there are means for registering the time of each radio contact with a mobile, means for calculating the difference between the time of its occurrence and said recorded time when a terminating pair occurs, and means for marking mobile as switched off if this difference exceeds a certain time.

Instead of having a time monitoring that is constantly ongoing for each subscriber, this function is thus solved in such a way that the current time is registered with each radio contact with a mobile phone. This timestamp thus contains the time when the last radio contact took place.

In the case of a terminating switch, the difference between the time of the terminating switch and the time stamp of the called subscriber is then calculated. If the difference between these time indications exceeds the time set by the operator for activity monitoring, the mobile phone is considered to have been switched off. The mobile is marked as turned off, and paging is not performed.

The invention provides a simple and robust mechanism for activity monitoring. This also provides additional benefits such as significantly lower development costs, as well as savings in processor capacity, when compared with previous solutions of activity monitoring.

Fig description.

The invention will now be described in more detail with reference to an exemplary embodiment shown in the accompanying drawing. More specifically, the single figure schematically illustrates the method according to the invention.

Preferred embodiment.

The upper first image in the figure illustrates in tabular form the contents of a subscriber data register, which is included in a mobile telephone station, marked as MSC in the following two images. The first column / memory location in the table identifies subscribers 1-n. The second column / memory location is intended for recording the time of radio contact with each subscriber, hereinafter also referred to as a time stamp. The third column / memory location is intended for marking adjacent to each subscriber, in the event of a terminating leash, if paging is to be performed or if detach marking is already set. The fourth column marks the place for other subscriber data.

The second, middle image illustrates how time stamp .arj 1, »5 is entered in the subscriber register upon radio contact with a subscriber.

The third, lower picture illustrates how, in the event of a terminating link to a subscriber, the subscriber's timestamp and the current time of the terminating link are read. The difference between these times is calculated, and determines whether paging should be performed or detach marking should be set.

The steps performed according to the invention are summarized below.

Radio contact with MS. J Record the time for this T1.

Link to MS. 1. Check if detachment marking is already set. If YES, disconnect the leash. If NO, continue. 2. Record the time for this torque (T2). 3. Calculate T2-T1 = T3, e.g. in number of minutes. 4. Check if the T3 exceeds the maximum time set by the MSC / VLR operator T4 for activity monitoring. 5. If YES, disconnect the coupler. Mark that the subscriber is in the "detach" state.

If NO, continue the leash.

The design of software and hardware in the mobile telephone station to enable the functions described above should be obvious to the person skilled in the art and therefore need not be described in more detail here.

Claims (2)

Patent claims A method of determining in a mobile telephone network when a mobile can be regarded as switched off, in order to be able to refrain from searching for the position of the mobile in question in the event of a terminating link to it, characterized in that the time of each radio contact with mobile is recorded. a terminating leash, the difference between the time of its occurrence and the said registered time is calculated, the mobile being marked as switched off if this difference exceeds a certain time. Device for determining in a mobile telephone network when a mobile phone can be regarded as switched off, in order to be able to refrain from searching for the position of the mobile phone in question in the event of a terminating link to it, characterized in that in mobile telephone stations included in the network means for recording the time of each radio contact with a mobile, means for calculating the difference between the time of its occurrence and said recorded time in the event of a terminating link, and means for marking mobile which is switched off if this difference exceeds a certain time.