CDMA vs GSM: Comparing Mobile Phone Technologies

[samarth joshi]

What is the difference between cdma and gsm mobile phones related to their working

 

[marcusl]

GSM (Global System for Mobile communications) is the most widely used cell phone system or standard in the world, with over 2 billion subscribers. There are many differences beween GSM and CDMA, but at the grossest level it is this: GSM uses TDMA (time division multiple access), that is, it allocates users on a freqency channel to different time slots. CDMA (code division multiple access) transmits to/receives from multiple phones at the same time in the same frequency channel and separates them by encoding the signal streams with mathematically orthogonal codes.

I suggest that you look CDMA, TDMA and GSM on Wikipedia for introductory material.

 

[ravenprp]

CDMA (Code Division Multiple Access) and GSM (Global System for Mobile Communications) are two different mobile phone technologies that use different methods for transmitting signals. The main difference between CDMA and GSM is the way they handle data and voice transmissions.

CDMA uses spread spectrum technology to allow multiple users to share the same frequency band simultaneously. This is achieved by assigning a unique code to each user, which allows their signals to be separated at the receiving end. This allows for more efficient use of the available bandwidth and higher capacity for data and voice transmissions.

On the other hand, GSM uses time division multiplexing (TDM) to divide the available frequency band into time slots and assign them to different users. This means that each user is allocated a specific time slot to transmit their data or voice signal, and then they have to wait for their turn to transmit again. This method is not as efficient as CDMA, as it limits the number of users that can access the network at the same time.

In terms of network coverage, GSM has a wider reach compared to CDMA. This is because GSM networks use smaller cells, which can be easily expanded to cover larger areas. CDMA, on the other hand, uses larger cells, which can be more difficult to expand and can result in gaps in coverage.

Another major difference between CDMA and GSM is in the way they handle roaming. GSM phones use SIM cards, which store subscriber information and allow users to switch between different networks. This makes it easier for GSM users to travel and use their phones in different countries. CDMA phones, on the other hand, do not use SIM cards and rely on network-based authentication, which can make it more difficult for users to switch between networks while traveling.

In terms of voice quality, both CDMA and GSM are equally capable of providing high-quality voice calls. However, CDMA is known to have better call quality in areas with low network coverage, as it can use a wider frequency band to transmit signals.

In conclusion, the main difference between CDMA and GSM mobile phones is the way they handle data and voice transmissions. CDMA is more efficient and can accommodate more users, while GSM has a wider network coverage and is more convenient for international travelers. Both technologies have their own advantages and disadvantages, and the choice between them ultimately depends on the user's needs and the availability of network coverage in their area.