Code division multiple access (CDMA) is a cellular frequency that, originally developed during World War II for military purposes, incorporates "spread spectrum" techniques. Unlike other cellular systems like GSM and TDMA, every channel on the network uses the full available spectrum. This allows each user (identified by a unique pseudonoise code (PN)) to communicate over several frequencies, as opposed to only one. CDMA is an improved version of TDMA (Time Division Multiple Access). TDMA uses a time-sharing protocol to provide three to four times more capacity than analog systems, just as a GSM.
QUALCOMM developed the key advances that made CDMA suitable for cellular phones and conducted an open demonstration in San Diego in November 1989.
The first CDMA network were launched commercially in 1995 as cdmaOne and provided approximately 10 times more capacity than analog networks. CDMA has become the fastest-growing of all wireless technologies, with over 100 million subscribers worldwide.
- Greater capacity. Provides 10-20 times the capacity of analog equipment and three times the capacity of other digital platforms.
- Excellent voice and call quality through the filtering out of background noise, cross-talk, and interference.
- Rapid deployment. CDMA systems can be expanded quickly and more cost effectively than most landline networks.
- Fewer dropped calls
- Improved security and privacy because of CDMA's digitally encoded transmissions. Reduced background noise and interference by combining multiple signals which improves signal strength
CDMA phones do not have the advantage of SIM cards, so forensics can only be done on the phone itself, as all relevant data is stored directly on the phone. This information includes the phonebook, call history log, SMS messages, and any calendar or to-do applications the phone might have.
Due to the fact that the phone must be physically connected to a forensics workstation for data acquisition, it is important to be aware of the phone's battary state (a charging cable should be obtained to ensure constant power), and blocking the phone's signal. Also, the correct data cable must be obtained to connect the phone to the workstation (Susteen provides a kit that includes many cables for the most popular phones).
Software for acquiring a CDMA-based phone includes: