GF82.70-P-0007-06RC General Information on Mobile Phone System

GF82.70-P-0007-06RC General Information On Mobile Phone System
- with CODE (523) MB Audio 20 radio
- with CODE (510) Audio 20 with CD changer

Component Identification:

Function requirements
^ Status "Circuit 30 ON" or "Circuit 15R ON"
^ One mobile phone network is available in sufficient strength and quality
^ Mobile phone system operating error-free
^ Mobile phone and "audio unit" switched on
^ Enabled Subscriber Identification Module (SIM) card inserted in mobile phone
^ Compatible mobile phone inserted into UPCI [UHI] cell phone holder (Universal Portable Cell Phone Interface) (A34/15), which is connected to Bluetooth module (A34/7) (comfort telephony), or Bluetooth-capable mobile phone authorized in vehicle and at "audio unit" (basic telephony)
^ Correct Personal Identification Number (PIN) entered, if set on the mobile phone

Depending on the equipment installed one of the following control units will be installed, hereafter referred to as the "audio unit":
- Radio (A2), with code (523) MB Audio 20 radio or with code (510) Audio 20 with CD changer
- Radio and navigation unit (A2/56), with code (525) MB Audio 50 APS radio or with code (511) Audio 50 APS with DVD changer
- COMAND operating, display and controller unit (A40/3), with code (527) COMAND APS with single DVD drive (with navigation) or with code (512) COMAND APS with DVD changer

In order to operate a mobile phone with Bluetooth capability that is also authorized at the "audio equipment" in the vehicle, the mobile phone must support Hands Free Profile (HFP) 1.0 or 1.5. More information is available under:
- www.mercedes-benz-mobile.com

General
In vehicles with code (494) USA version, the mobile telephone network is a digital, cellular wireless network based on the Code Division Multiple Access (CDMA) standard. In vehicles without code (494) USA version, the mobile telephone network is a digital, cellular wireless network based on the Global System Mobile (GSM) standard.
The CDMA or GSM standards represent the normalization of the mobile phone system. The purpose is to offer compatible cellular phone services.
This system transfers dialing information, voice as well as data, digitally. Moreover, additional services are offered, such as:
- Fee display
- Conference calls, calls waiting
- Identification of calling partners
- Call relaying
- Fax, with GSM standard

Radio transmission in the mobile telephone network takes place between the mobile phone and the base transceiver station.

The transmission frequencies vary depending on the frequency band, as shown in the following example:
- Uplink (1850 up to 1910 MHz), with CDMA standard
- Downlink (1930 up to 1990 MHz), with CDMA standard
- 900 up to 1900 MHz, with GSM standard

As of the base transceiver station, all signals are forwarded via cables to the base station controller.
The base transceiver stations of a cellular mobile telephone network are arranged so that a network of honeycomb-shaped radio cells is formed to provide cellular mobile telephone subscribers with a mobile telephone network that is available across the whole area.
In high population centers, it is necessary for the radio telephone cells to serve a large number of subscribers while in rural areas, it is possible to cover larger radio reception and transmission areas. These radio telephone cells have a range of 100 m to 40 km, depending on the requirements. A feature of cellular mobile telephone networks is the automatic handover from one radio cell to the next, without the cellular phone subscriber noticing anything.

When the range of a base transceiver station is exited during a call and the subscriber moves into the transmission range for the next base transceiver station, the call can be continued without interruption even though the transmitter in the next base transceiver station transmits on a different frequency.

This handover procedure is accomplished within 5 to 10 ms. Transmission problems can occur if the mobile phone subscriber is located in valleys and low spots (radio shadows) or in areas with a small number of base transceiver stations. However, these transmission problems can usually be eliminated by moving to a different location.
In vehicles with GSM standard it is possible to make phone calls when abroad using the mobile phone and the SIM card. This requires the particular country to have the GSM standard, a corresponding contract (roaming contract) between the country and the network provider and the mobile phone to be dual-band or tri- band, depending on the different frequencies.

A radio cell is formed by the transmission and reception area of a base transceiver station. The base transceiver station completes the connection to the cellular phones, controls radio telephone transmission and transfers the information to the base station controller via cable.
With the GSM standard, 124 or 372 channels are available for each base transceiver station, depending on the frequency. The base station controller is the controller unit for the base transceiver station.
The base station controller is connected between the base transceiver station and the mobile service switching center. The base station controller transmits the useful data for voice and data communication as well as monitoring and control. Moreover, it is the central control point for automatic handover from one radio cell to the next.
The mobile service switching centers are networked with each other and form the switching system in mobile telephone networks with CDMA standard or with GSM standard. Here, the various databases and lists of visitors and visitor data are stored.

Databases and directories in the mobile service switching centers
They are divided up into the following areas:
^ Home location register
^ Equipment database
^ Visitor register
^ Authentication center

Home location register
This is where subscriber master data is stored, such as name, address, telephone number, service features, caller and call destination numbers, information about time, duration of and charges for the phone call, and information about the radio cells in which a connection has been established and terminated again.

Equipment database
This is where the International Mobile Equipment Identity (IMEI) number for the specific mobile phones is registered. This IMEI number is sent by the mobile phone during registration. If the mobile phone is blocked or stolen, access to the mobile phone network can be refused.

Visitor register
This is where the necessary data of a visiting mobile radio subscriber are temporarily stored.

Authentication center
This is where the access authorization of the cellular phone subscribers is checked, and the relevant connection is switched.

The entirety of the public mobile telephone network is referred to as the Public Switched Telephone Network.