Mobile Communications: GSM Architecture

In this video, we discuss about second generation (2G) of mobile communication, specifically, we talk about GSM architecture.

It all starts from when we dial any number from our mobile then first we get connected with a tower. Tower has associated entities of BTS and TRX. Base Transceiver Station (BTS): consists of amplifier and signal processing, modulation, multiplexing, channel measurement, power management. Transceiver (TRX): Transmitter and Receiver

Cell is geographical area covered by one base station.
Mobile station consists of mobile equipment (ME) and subscriber identity module (SIM). Every mobile equipment is identified by International Mobile Equipment Identity (IMEI): A 15-digit number unique to each device, can be used for tracking mobiles. Subscriber Identity Module (SIM): holds information like Authentication, charging, storage.

Base Station Controller (BSC): To control and monitor BTS traffic, handover. Handover is a process of transferring a call from one channel to other.

Mobile services switching center (MSC): It perform switching to other MSC, BSC and fixed networks (PSTN).
MSC is connected with:
Home Location Register (HLR):
Visitor Location Register (VLR):
Equipment Identity Register (EIR):
Authentication Centre (AuC):
Operation and Maintenance Center (OMC):

Radio Sub System (RSS): To establish and maintain radio (wireless) signal between a user and rest of the system. It includes MS, BTS and BSC
Network and Switching Subsystem (NSS): It is used for switching between wireless system and other system (PSTN). Handover between BSS
Operation Sub-System (OSS): The combination of jobs performed by EIR, AuC and OMC

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