Overview of Cellular Networks

A cellular network is called so as it is created of many cell like structures connected to each other. The cells are hexagonal in shape like a honeycomb. Every cell has a tower that is responsible for providing “Network Access” to all the cellular mobile phones in that cell. 


Why are Cellular Networks, Cellular?


Cellular networks work on radio wave frequencies that are assigned to them and within these limited, shared frequencies they need to try and accommodate as many users as possible. Cellular networks are arranged as cells as it helps frequency reuse, bandwidth optimization and hence supports more cellular phone users. The hexagonal cell structure was found to be the best structure for implementing cellular networks as it helps reach the most number of people without conflicting frequencies or sacrificing on the number of cellular mobile phones that are being used.


How do Cellular Phones work?


When a cellular phone user makes a call, it reaches the towers which are called as BTS – Base Transceiver Station or cell site and which houses transceivers as its name suggests. A transceiver is also called as a TRX and it is basically a device that helps in transmitting and receiving radio signals. The TRX aka DRX – Driver Receiver will be in contact with the cellular phone or any other User Equipment. It is used primarily to send and receive signals over the radio frequency. 


The BTS forms a part of the BSS Base Station Subsystems and it is controlled by a parent Base Station Controller via the BCF Base Station Controller Function. The BTS takes input from the UE under guidance from the BCF and passes the same on to the BSC Base Station Controller. The signals from the BSC are passed on to MSC.


The MSC or the Mobile Switching Center is where the call signals from the User Equipment are passed on further to the number it intends to connect to. A MSC is a soft switch that provides facilities for calling and receiving calls to numbers registered in the network and also outside it – roaming. It uses various databases like HLR and VLR for this purpose. 


Once the call is forwarded from the MSC it reaches another MSC or a BTS and connects to the user the call is dialed to. The whole function happens in a matter of seconds.