sub c battery GSM System Architecture
GSM represents the global mobile communication system.This paper aims to provide an introductory guide to GSM system architecture.1.GSM represents the global mobile communication system.This is the standard originally created to solve the compatibility of European 1g cellular systems and devices.Initially, it works in the 900 MHz band, but then 1.8 GHz and 1.9 GHz band is also supported.2.The GSM system architecture consists of six basic components of the GSM system architecture: a) there are two components in the wired system Gateway: MSC (mobile switching center) and IWF (networking function ).MSC provides a link between the GSM network and the PSTN (public switched telephone network.IWF provides links to the internet for IP data traffic.The MSC and IMF together with four databases (HLR, VLR, AuC and EIR) form the NSS (Network Switching Subsystem ).NSS processes GSM call switching between BSCs and MSC for communication with external networks.B) Base station subsystem (Base) BSS consists of one BSC (Base station controller) and one or more BSC (Base station receiving and receiving station.Several MSC are connected to one MSC.The MS provides and manages radio transmission between (mobile radio station) and MSC.BSC connects and controls many BTSs via microwave or wired.It retains the frequency, handles the mobile switching between two BTSs within the same BSS, and controls paging.The BTS consists of all radio equipment in a single cell, such as radio antennas and radio transceivers.It performs all the signaling related to the radio interface, which is the logical location of the antenna.C) there are three main databases in the database: HLR represents the Home Location Register.It stores subscriber information and location information for each user belonging to MSC.HLR also stores billing information.VLR represents the register of visitor locations.It stores all roaming users currently within a specific MSC range.It contains information about roaming users such as authentication information, IMSI (International Mobile user identity) and MSRN (Mobile Station Roaming Number ).EIR identifies the register on behalf of the equipment.It is related to security issues and will be discussed in the next section.D) the security mechanism consists of three sub-components: AuC represents the Certification Center.When a user joins the network and tracks the user, it performs the necessary authentication.It controls access to user data by implementing an encryption algorithm for all users' requests, such as HLR and VLR.EIR is a database that stores IMSI (International Mobile user identity) for each mobile device.By matching IMSI and IMEI (International Mobile device identity), it can identify any mobile phone that has been stolen or illegally changed and block calls from those phones.The SIM card represents the user identity module.It is a smart card that stores the user's personal data and billing information and is inserted into the mobile device.SIM is used to authorize users to access the network.E) the air interface GSM controls the transmission media using the TDMA (time division multiple access) protocol.It adopts Gaussian minimum shift key modulation scheme with a channel bandwidth of 200 kHz.F) the mobile station (MS) consists of a mobile device (ME) and a SIM card.The MS communicates with the BTS in the same cell where the MS is located through the radio air interface Um.ME is basically a mobile device that does not include SIM cards.3.This paper aims to provide an introductory guide to GSM system architecture.It tries to break down the GSM architecture into six logical components so that readers can have a clear understanding of the system architecture even without a technical background