GSM vs CDMA

GSM

GSM is a ‘cellular’ technology, that is, the entire coverage area is divided into various hexagonal shaped cells (hence the popular name ‘cell phones’). Every cell has a corresponding network tower, which serves the mobile phones in that cellular area. For example: Imagine a honeycomb on a tree in a hexagonal shaped garden. The garden has many flowers. The honeybees collect the nectar from the flowers, and deposit it in the honeycomb. Your mobile phones are like the flowers, the network tower is like honeycomb, and the bees are the signals.

CDMA

As the name suggests (Code Division Multiple Access), there are many devices which use the same spread spectrum (hence multiple access). There is one physical channel, and a special code for every device in the coverage network. Using this code, the signal of the device is multiplexed, and the same physical channel is used to send the signal (the codes may or may not change). For example: There is a street on which many buses ply. Obviously, the bus will have many commuters, and they will have to buy the tickets to travel on the bus. In CDMA, the commuter is like your mobile phone, the tickets are your codes, the bus is a multiplexed carrier signal, and the street is the spread spectrum.

SOURCE:      CDMA vs GSM