Locate subscribers in mobile networks

Recently, many mass media have posted the phenomenon of mobile service providers to reveal customer information, including subscribers, leading to conflicts in the family.

Even, there are customers who still sue service providers for this reason.In the article below, we will help readers better understand the ability of subscribers to determine the location of mobile networks.

Mobile customers are exposed to the main reason information from the service provider.

In essence, the structure of the mobile phone network consists of many broadcast base stations (BTS).Each BTS is usually divided into 3 cells (cell) with a 120 ⁰ directional broadcast angle.This transceiver station serves limited subscribers within a certain radius, usually from 500m (in densely populated cities) to 15km (in provincial and district centers).

Due to the mobile nature of subscribers, network providers must be able to manage these subscribers.And know exactly where the subscriber is when they move.Therefore, on the switchboard system always keep information about the location and travel journey of the current subscriber, regardless of whether they make the call or not (of course, with the subscriber still turning on the device) .When the subscriber turns off the phone, their last position is saved on the switchboard with the time of shutdown (leaving the network).

Subscriber location is saved on the billboards, helping operators to charge correctly, keeping the call clear when the subscriber moves from the coverage area of ​​this BTS to another BTS.This information also helps network providers detect possible frauds such as problems stealing SIM information to make unauthorized calls, duplicate unauthorized SIMs.For example: A subscriber has just made a call in Hanoi, then 15 minutes later make another call in Ho Chi Minh City, ie two people use the same SIM.In this case, the operator will recommend customers to switch to a new SIM to eliminate the possibility of disclosure.

Currently, GSM networks (including CDMA networks) that are being exploited in Vietnam have not yet applied the ability to determine the location of subscribers in the exact coordinates and directions but often only based on the location. of BTSs according to relative geographic locations.For example, when the subscriber is in BTS A, we can understand that the subscriber is in the area of ​​radius from 500m-15km around A only.However, for 3G networks (W-CDMA), the ability to determine the location of subscribers is very accurate with the error calculated in meters because these systems use global positioning technology (GPS). via satellites to locate subscribers.This technology is very useful when deploying applications such as mobile phone search or search and rescue.

However, customers themselves cannot know the location information or any other information of other subscribers.Therefore, the disclosure of customer location information often comes from the service provider, or those who have access to the switchboard system and the new subscriber fee system.Most customers who know this information have a relationship with those who work at mobile phone exchanges.Therefore, in case of disclosure of the above information, customers should immediately report to the responsible person from the supplier for assistance and satisfactory answers.