A comparative study of GSM & CDMA technology
- Executive summary
- Current market situation
- The network structure of GSM
- The cellular showdown: CDMA vs. GSM
- Technology in practice
- GSM service providers
- CDMA service providers
The mobile industry in India is divided between the two technologies GSM and CDMA. While the earlier service providers had adopted the GSM technology, the new players have been using CDMA technology and have notched up a significant share of the Indian market. Hence any discussion on Mobile Forensics needs to take into account the presence of the two technologies.
It is necessary for us to understand the basic differentiation of the two technologies as they may have an impact on the Forensics. An attempt is made here to present the fundamental technical aspects about the two systems.
GSM stands for Global System for Mobile Communications and CDMA stands for Code Division Multiple Access. They represent different systems of sharing of the radio spectrum for communication.
Normally the radio spectrum can be shared by different users accessing the same frequency band without causing interference. The techniques used for this are TDMA (Time division multiple access), FDMA (Frequency division multiple access) and CDMA (Code division multiple access).
GSM (Global System for Mobile Communications) is a form of multiplexing, which divides the available bandwidth among the different channels.
[...] GSM is the ?branded? term referring to a particular use of TDMA (Time-Division Multiple Access) technology. GSM is the dominant technology used around the globe and is available in more than 100 countries. It is the standard for communication for most of Asia and Europe. GSM operates on four separate frequencies: You'll find the 900MHz and 1,800MHz bands in Europe and Asia and the 850MHz and 1,900MHz (sometimes referred to as 1.9 GHz) bands in North America and Latin America. [...]
[...] On the other corner, CDMA followers say it is better "because it is the 3G generation chosen technology and GSM will migrate to CDMA since CDMA is more advanced . " But which one of these statements are correct? Accordingly to Nokia, "this discussion is not about technology anymore, but about market". We think this is the best way to describe the war between these two cell phone technologies. In the beginning, GSM was in fact superior. It had more services and allowed more data transfer. [...]
[...] GSM SECURITY GSM was designed with a moderate level of security. The system was designed to authenticate the subscriber using shared-secret cryptography. Communications between the subscriber and the base station can be encrypted. The development of UMTS introduces an optional USIM, that uses a longer authentication key to give greater security, as well as mutually authenticating the network and the user - whereas GSM only authenticated the user to the network (and not vice versa). The security model therefore offers confidentiality and authentication, but limited authorization capabilities, and no non- repudiation GSM uses several cryptographic algorithms for security. [...]