11 Facts About CDMA


CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel.

FactSnippet No. 998,373

Space-based communication applications, CDMA has been used for many decades due to the large path loss and Doppler shift caused by satellite motion.

FactSnippet No. 998,374

CDMA is often used with binary phase-shift keying in its simplest form, but can be combined with any modulation scheme like quadrature amplitude modulation or orthogonal frequency-division multiplexing, which typically makes it very robust and efficient .

FactSnippet No. 998,375

The technology of CDMA was used in 1957, when the young military radio engineer Leonid Kupriyanovich in Moscow made an experimental model of a wearable automatic mobile phone, called LK-1 by him, with a base station.

FactSnippet No. 998,376

Each user in a CDMA system uses a different code to modulate their signal.

FactSnippet No. 998,377

Related searches

Doppler shift Moscow

CDMA is analogous to the last example where people speaking the same language can understand each other, but other languages are perceived as noise and rejected.

FactSnippet No. 998,378

In general, CDMA belongs to two basic categories: synchronous and asynchronous .

FactSnippet No. 998,379

Each user in synchronous CDMA uses a code orthogonal to the others' codes to modulate their signal.

FactSnippet No. 998,380

In other words, asynchronous CDMA is ideally suited to a mobile network where large numbers of transmitters each generate a relatively small amount of traffic at irregular intervals.

FactSnippet No. 998,381

Novel collaborative multi-user transmission and detection scheme called collaborative CDMA has been investigated for the uplink that exploits the differences between users' fading channel signatures to increase the user capacity well beyond the spreading length in the MAI-limited environment.

FactSnippet No. 998,382

An enhanced CDMA version known as interleave-division multiple access uses the orthogonal interleaving as the only means of user separation in place of signature sequence used in CDMA system.

FactSnippet No. 998,383