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Video services are becoming an integral part of future communication systems. Especially for the upcoming 3G-CDMA system wireless networks such as UMTS, video may very well turn out to be the key value addition that achieves the required return of investment. While previous generations of wireless communication systems were primarily designed and used for voice services, next generation systems have to support a broad range of applications in a wide variety of settings. The early market stages were characterized by the needs of early adopters, mostly for professional use. As the market matures from the early adopters to normal users, new services will be demanded. These demands will likely converge toward the demands that exist for wired telecommunications services.




Market research finds that mobile commerce for 3G wireless systems and beyond will be dominated by basic human communication such as messaging, voice, and video communication. Because of its typically large bandwidth requirements, video communication (as opposed to the lower rate voice and the elastic e-mail) is expected to emerge as the dominant type of service in 3G/4G wireless systems. Video services obth real-time services and streaming services are gaining a lot of importance and applications in CDMA systems.

Introduction to CDMA:

CDMA is a form of Direct Sequence Spread Spectrum communications. In general, Spread Spectrum communications is distinguished by three key elements:

1. The signal occupies a bandwidth much greater than that which is necessary to send the information. This results in many benefits, such as immunity to interference and jamming and multi-user access, which we’ll discuss later on.

2. The bandwidth is spread by means of a code which is independent of the data. The     independence of the code distinguishes this from standard modulation schemes in which the data modulation will always spread the spectrum somewhat.

3.The receiver synchronizes to the code to recover the data. The use of an independent code and synchronous reception allows multiple users to access the same frequency band at the same time.


In order to protect the signal, the code used is pseudo-random. It appears random, but is actually deterministic, so that the receiver can reconstruct the code for synchronous detection. This pseudo-random code is also called pseudo-noise (PN).

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