Mobile Handset [Return to main Technology page]

The main function of the SIM is in conjunction with the network, to authenticate the MS. The SIM is removable and stores details such as:

1) Authentication Key

2) International Mobile Station Identity (IMSI)

3) Cipher Key

4) Temporary Mobile Subscriber Identity (TMSI)

5) Location Area ID

6) List of carriers for cell selection.

The ME comprise of the software and hardware allowing it to operate as a mobile radio terminal. The ME will have a unique International Mobile Equipment Identity (IMEI), allowing it to be verified by the Equipment Identity Register (EIR).

A GSM MS has by definition a number of operational modes:

1) No service

2) Limited Service

3) Idle Mode

4) Dedicated Mode

No Service occurs when the MS can't find GSM coverage. A mobile that can't find a suitable cell may acquire any cell and offer a Limited service (Emergency call only). When a GSM mobile camps on a cell, it is said to be in idle mode. Once MS has accessed a cell and is communicating with the network, it is in dedicated mode.

MS Power capability

The power ratings for the mobile are measured at the antenna connector. The Tx power of the mobile depends upon how far it is away from the base station. Hence it can use any power between Max and Min power capability. Basically the further the mobile is from the base station the more power it will use up to it's maximum limit.

GSM 900
Class1: Max Tx Power 20W but no Min specified.
Class2: Max Tx Power 8W and Min Tx Power 3.2mW
Class3: Max Tx Power 5W and Min Tx Power 3.2mW
Class4: Max Tx Power 2W and Min Tx Power 3.2mW
Class5: Max Tx Power 0.8W and Min Tx Power 3.2mW

DCS 1800
Class1: Max Tx Power 1W and Min Tx Power 1mW
Class2: Max Tx Power 0.25W and Min Tx Power 1mW
Class3: Max Tx Power 4W and Min Tx Power 1mW

UMTS User Equipment (UE)

The Mobile Equipment (ME) is the radio terminal used for UMTS radio communication. The UMTS Subscriber Identity Module (USIM) is a smart card that holds the subscriber identity, performs authentication algorithms, and stores authentication and encryption keys including subscription information. The handsets will vary from data terminals such as PDA's to mobile equipments similar to one's currently used for GSM. However they will all offer higher data rates compared to current handsets.

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