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Gsm is what network, gsm network knowledge all-round analysis
Jun 01, 2017

Gsm is a digital mobile communication standard developed by the European Telecommunications Standards Organization (ETSI), which was used in the mid-1990s and now has more than 200 countries. Over 1 billion people are using some of the system networks. GSM is an open standard developed by 3GPP, using time division multiple access technology.


GSM standard in the mobile phone operators signed between the "roaming agreement" after the user's international roaming becomes very simple. The biggest difference between GSM and its previous standard is that his signaling and voice channels are digital, so GSM is seen as a second generation (2G) mobile phone system.


GSM antenna frequency configuration

At present, China Mobile, China Unicom each have a GSM network, the world's largest mobile communications network. GSM system includes GSM 900: 900MHz, GSM1800: 1800MHz and GSM1900: 1900MHz and other frequency bands.


1, GSM 900MHz band duplex interval of 45MHz, the effective bandwidth of 25MHz, 124 carrier frequency, each carrier frequency of 8 channels. GSM900: uplink 890-915MHz; downlink 935-960MHz

China GSM900 use frequency

A. China Mobile: uplink frequency band: 890-909 MHz, downlink frequency band: 935-954 Mhz

B. China Unicom: uplink frequency band: 909-915 MHz, downlink frequency band: 954-960 Mhz


2, GSM 1800MHz band duplex interval of 95MHz, the effective bandwidth of 75MHz, 374 carrier frequency, each carrier frequency of 8 channels. Upstream: 1710-1785MHz; Down: 1805-1880MHz

A. China Mobile: uplink frequency band: 1710-1720MHz, downlink frequency band: 1805-1815Mhz

B. China Unicom: uplink frequency band: 1710-1785Mhz, downlink frequency band: 1805-1880Mhz

GSM system architecture

    GSM system mainly consists of mobile station (MS), mobile network subsystem (NSS), base station subsystem (BSS) and operation support subsystem (OSS) four parts.

Gsm is what network gsm network knowledge all-round analysis

1, the mobile station is a public GSM mobile communication network users use the device, but also users can directly contact the entire GSM system in the only device. The type of mobile station includes not only the handheld, but also the car and the portable station. With the GSM standard digital handhelds to further small, lightweight and increase the trend of functional development, handheld users will account for a large part of the entire user.

2, base station subsystem (BSS) GSM system is the most direct relationship with the wireless cellular basic components. It is directly connected with the mobile station through the wireless interface, responsible for wireless transmission and reception and radio resource management. On the other hand, the base station subsystem is connected to the mobile service switching center (MSC) in the network subsystem (NSS) to realize communication connection between the mobile subscriber or between the mobile subscriber and the fixed network user, the transmission system signal and the user information The Of course, the BSS part of the operation and maintenance management, but also to establish BSS and operation support subsystem (OSS) between the communication connection.

3, mobile network subsystem (NSS) mainly contains the GSM system switching function and for user data and mobility management, security management required database functions, it GSM mobile users and GSM mobile users and other mobile Communication between the communication network users play a management role. NSS consists of a series of functional entities, the entire GSM system, that is, between the NSS functional entities and between NSS and BSS through the CCITT signaling system No.7 protocol and GSM specification on the 7th signaling network to communicate with each other The

4, the operation support subsystem (OSS) to complete many tasks, including mobile user management, mobile device management and network operation and maintenance.