CDMA Technology

Abstract :

CDMA was developed by QUALCOMM Incorporated, a company in San Diego, California. QUALCOMM engineers decided to do something different and applied spread spectrum techniques to a multiple access system, which ultimately became CDMA.
In spread spectrum, instead of giving each person a channel, or each group of 3 or 8 people a time slot, CDMA puts everyone in the same channel at the same time.
At first thought, it would seem to be an impossible task to make work, but it does work. The reason it works is expla ....etc

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CELLULAR AND MOBILE COMMUNICATIONS DS-CDMA
Presented By:
V.VIJAYA KUMAR, IV B.Tech E.C.E
SREE VIDYANIKETHAN ENGINEERING COLLEGE ,TIRUPATI


ABSTRACT

So far transmission errors have been described as evil entity in communication literature. Introducing error intentionally can save power and reduce interference. This has been proved by scientists Jik Dong Kim (South Korea), Sang Wu Kim (USA) and Young Gil Kim (South Korea). It is about combined power and error control in multicarrier DS-CDMA systems ....etc

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The Internet and Mobile Wireless are the defining technologies of our times. Today, they are converging and promising to dramatically reshape society. Mobile Internet services will help people work, entertain, and communicate anytime, anywhere-using a variety of devices such as cell phones, Personal Digital Assistants (PDAs), and laptops. Driven by the Wireless Internet?s enormous potential and reacting to declining Mobile voice revenues per subscriber, operators are pegging their future growth on Wireless Internet services.

While operators ....etc

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The world is demanding more from wireless communication technologies than ever before. More people around the world are subscribing to wireless services and consumers are using their phones more frequently. Exciting Third-Generation (3G) wireless data services and applications - such as wireless email, web,digital picture taking/sending and assisted-GPS position location applications - and wireless networks have also arrived and asked to do much more than just a few years ago. This is where CDMA technology fits in. CDMA consistently provides be ....etc

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Topic: fuzzy based call admission control in wideband cdma cellular networks

ABSTRACT
In this paper, a novel call admission control (CAC) scheme using fuzzy logic is proposed for the reverse page link transmission in wideband code division multiple access (CDMA) cellular communications. The fuzzy CAC scheme first estimates the effective bandwidths of the call request from a mobile station (MS) and its mobility information, and then makes a decision to accept or reject the connection request based on ....etc

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Overview
Code division multiple access (CDMA) is a modulation and multiple-access scheme based on spread-spectrum communication. In this scheme, multiple users share the same frequency band at the same time, by spreading the spectrum of their transmitted signals, so that each user's signal is pseudo-orthogonal to the signals of the other users.

CDMA Signals
In a CDMA system, each signal consists of a different pseudorandom binary sequence (called the spreading code) that modulates a carrier, spreading the spectrum of the waveform. A large ....etc

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Multiple access (MA) schemes are used to simultaneously share available bandwidth in communication systems. In conventional MA applications a finite and contiguous amount of spectrum which is designated for a particular service is allocated to multiple users. Therefore, the use of designated radio spectrum is unconstrained and can be utilized in many ways to achieve maximum efficiency. Time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA) are the three major MA techniques. In r ....etc

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(Code Division Multiple Access) A method for transmitting real-time signals over a shared portion of the spectrum. The foremost application of CDMA is the digital cellular phone technology that operates in the 800MHz band and 1.9GHz . Unlike GSM and TDMA, which divides the spectrum into different time slots CDMA uses a spread spectrum technique to assign a code to each conversation. After the speech codec converts voice to digital, CDMA spreads the voice stream over the full 1.25MHz bandwidth of the CDMA channel coding each stream separately s ....etc

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MOBILE COMMUNICATIONS
(IMPLEMENTATION OF CDMA TECHNOLOGY IN CELLULAR
PHONES)
Presented By:
M.Vamsi Krishna
B.kiran sai phaneswar


ABSTRACT:

A wireless digital communication system is a technique that allows people to communicate each other at a distance. In this paper we tried to explain one of the latest technologies of digital wire less communication systems - The CDMA and the application of this on cellular phones.CDMA is an acronym for code division multiple ....etc

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TCP-Aware Channel Allocation in CDMA Networks-IEEE Jan. 2009

Abstract

explores the use of rate adaptation in cellular networks to maximize throughput long-lived TCP sessions. We focus on the problem of maximizing the throughput of TCP connections and propose a joint optimization of MAC and physical layer parameters with respect to TCP sending rate. In particular, propose a simple TCP-aware channel scheduler that adapts the wireless channel rate to changes in the TCP sending rate and explore its performance for both single and multiple co ....etc

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