Code division multiple access - Technical details

Code division multiple access (CDMA) is (not a modulation scheme, but a form of multiplexing) a method of multiple access that does not divide up the channel by time (as in TDMA), or frequency (as in FDMA), but instead encodes data with a certain code associated with a channel and uses the constructive interference properties of the signal medium to perform the multiplexing. CDMA also refers to digital cellular telephony systems that makes use of this multiple access scheme, such as those pioneered by Qualcomm, or W-CDMA. < ...

Including:

• Code division multiple access - History of CDMA
• Code division multiple access - Usage in mobile telephony
• Code division multiple access - Technical details
• Code division multiple access - Mathematical foundation
• Code division multiple access - Implementation
• Code division multiple access - Soft Handoff
• Code division multiple access - CDMA features

Read more here: » Code division multiple access: Encyclopedia - Code division multiple access

Code division multiple access - Mathematical foundation. CDMA exploits at its core mathematical properties of orthogonality. Suppose we represent data signals as vectors. For example, the binary string "1011" would be represented by the vector (1, 0, 1, 1). We may wish to give a vector a name, we may do so by using boldface letters, eg a. We also use an operation on vectors, known as the dot product, to "multiply" vectors, by summing the product of the components. For example, the dot product of (1, 0, 1, ...

See also:

Code division multiple access, Code division multiple access - History of CDMA, Code division multiple access - Usage in mobile telephony, Code division multiple access - Technical details, Code division multiple access - Mathematical foundation, Code division multiple access - Implementation, Code division multiple access - Soft Handoff, Code division multiple access - CDMA features

Read more here: » Code division multiple access: Encyclopedia II - Code division multiple access - Technical details

A number of different terms are used to refer to CDMA implementations. The original standard spearheaded by QUALCOMM was known as IS-95, the IS referring to an Interim Standard of the Telecommunications Industry Association (TIA). IS-95 is often referred to as 2G or second generation cellular. The QUALCOMM brand name cdmaOne may also be used to refer to the 2G CDMA standard. After several revisions, IS-95 was superseded by the IS-2000 standard. This standard was introduced to meet some of the criteria laid out in the IMT-2000 specific ...

See also:

Code division multiple access, Code division multiple access - History of CDMA, Code division multiple access - Usage in mobile telephony, Code division multiple access - Technical details, Code division multiple access - Mathematical foundation, Code division multiple access - Implementation, Code division multiple access - Soft Handoff, Code division multiple access - CDMA features

Read more here: » Code division multiple access: Encyclopedia II - Code division multiple access - Usage in mobile telephony