GSM

Once the mobile is switched on and the registered home PLMN was selected (e.x. SMART), it will next search for a BCCH frequency list, stored in its memory or in its SIM card. The list can have up to 32 BCCH frequencies for the mobile to scan. This reduces the time of cell selection, compared … Read more

When the mobile is switched on it will select the registered PLMN in the mobile if there exist one. If there is no registered GSM PLMN or the registered PLMN is not available (no coverage) then the GSM mobile will try to select another GSM PLMN either automatically or manually depending on it mode. AUTOMATIC … Read more

The SIM card contains its internal memory, in which the data, personal and financial information as well as the identity for GSM / CDMA are stored. The SIM card stores network-specific information in order to authenticate the identity of the subscriber in the network. SIMs were first launched in 1992 with the first digital “GSM” … Read more

MOBILE STATIONS ISDN NUMBER (MSISDN) Is the mobile number used in a GSM PLMN (Public Land Mobile Network) MSISDN = Country Code + National Destination Code + Subscriber number e.x. 63 + 0918 + 8889999 Maximum length is 15 digits. INTERNATIONAL MOBILE SUBSCRIBER IDENTITY (IMSI) Is the subscriber number used over radio path for all … Read more

In RF Hopping mode, each route of service information is processed by fixed base band unit and and carrier frequency processing unit, while the working frequency carrier of carrier frequency processing unit is provided by frequency synthesizer. Under the control of the control unit, frequency carrier can be changed according to certain rules. This mode … Read more

There are a number of relatively independent base band processing units and carrier processing units in the system. The working frequency carrier of each carrier processing unit is fixed, the service information of each communication path is processed by fixed base band unit, and then the processed information is transferred to carrier units of different … Read more

When you decide to apply hopping to any BTS then below parameter require to previously defining. All the parameters which are related to hopping are configured in cell/configure Hopping data Hopping mode: the mode used by the BTS system, including three options: not hopping, base band hopping and RF hopping. MA (Mobile Allocation Set): the … Read more

In GSM system, the interference strength and distribution on each frequency carrier in cell are different, the carrier variation of the bursts of the same communication low the interference on signal, the radio wave interference on communication is equalized. If no hopping is used, the mobile station will always work on fixed frequency carrier, each … Read more

Hopping can lower the influence of Rayleigh fading to signal strength. This influence equals to frequency diversity. One voice code block of GSM is transmitted in 8 bursts separately after channel coding. Since the Rayleigh fading is based on frequency, in other words, the valley point of signal fading appears in different locations at different … Read more

Hopping can lower many kinds of interferences, such as co-channel interference, adjacent channel interference, inter modulation interference, etc. Hopping turns the consecutive long time interference of mobile station into discontinuous interference of single burst, and such interference can be greatly lowered through channel decoding, de-interleave and error correction technology. After hopping technology is adopted, GSM … Read more