The technicality of cdma technology has given significant advantages over other parallel technologies in terms of spectrum efficiency and overall performance. Pdf code division multiple access cdma system in multipath. Cdma is known to be an outdated technology largely due to networks global reach issue but it is not so. A free powerpoint ppt presentation displayed as a flash slide show on id. Mobile device investigations program technical operations division dfb. Ac05 gps tracker label diagram 1 mlabs technologies. Introduction to 5g raj jain washington university in saint louis saint louis, mo 63. Cdma is the short form of code division multiple access. Incremental progress 1g amps data capabilities 30 khz.
Cdma, which stands for code division multiple access, is a competing cell phone service technology to gsm, the worlds most widely used cell phone standard. A short history of network evolution is provided in order set the context for understanding gsm. Basics of code division multiple access cdma 2005 rao. Wide band cdma technology is selected for utran air interface. Basic network design frequency reuse and planning 1. Example of how the data from three different users is spread using codes, combined and sent as a single waveform, and then how the data from each user. With fdma, each channel can be assigned to only one user at a time. Time division multiple access tdma is a more complex technique, for it needs a. Cellular technology enables mobile communication because they use of a complex two way radio system between the mobile unit and the wireless. Youve probably heard of these acronyms when you were told that you cant use a certain phone on your mobile network because theyre using different technologies that are not compatible. W cdma occupies 5 mhz channels and has defined formats for elements such as synchronisation, power control and the like. This cdma tutorial describes cdma basics by explaining pn sequence codes, walsh codes, cdma physical layer for base station and mobile subscriber. These two technologies differ in the way calls and data travel over the mobile phone networks take place.
This web site is an excellent resource for understanding cdma technologies, its benefits and evolution. Table of contents 1 introduction 2 basics of cdma basic properties of cdma systems ds cdma. Cdma is actually a newer technology than gsm and it offers some of the newest calling and data options evdo rev. To much noise will cause interference leading to degraded service or dropped calls. Code division multiple access each user is assigned a binary, direct sequence code during a call. S cdma basics what synchronous code division multiple access s cdma is an upstream technology added in d2. Document includes id labellocation info id labellocation info 1. Cdma tutorial for beginners learn cdma online training. Cdma is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. The basic principle is that different cdma codes are used to distinguish between the different users.
Code division multiple access cdma is a sort of multiplexing that facilitates various signals to occupy a single transmission channel. This article discusses on the difference between gsm and cdma in terms of technology, security, global reach, sim card, flexibility, radiation emitted. Cdma technology is known as a spreadspectrum technique which allows many users to occupy the same time and frequency allocations in a given band and space. Cdma i about the tutorial code division multiple access cdma is a channel access method normally used by 3g radio communication technology as well as in some other technologies. In code division multiple access cdma systems all users transmit in the same bandwidth. Basics of wireless and mobile communications wireless transmission frequencies signals antenna signal propagation multiplexing modulation spread spectrum cellular systems media access schemes motivation sdma, fdma, tdma, cdma comparison basic functions in mobile systems. Cdma basics a unique code is assigned to all digital speech bits and the. An overview of cdma2000 technology concepts an overview of cdma2000 technology concepts 1 1 1 1 1 1 1 1 1 1. Mobile device investigations program technical operations. Basics of code division multiple access cdma spie digital library. Comprehensive coverage of umts 3g news, licensing, business developments, 3g wcdma telecommunication technology, multi media mobile phones and future communications.
Codedivision multiple access cdma is a channel access method used by various radio communication technologies. This page of tutorials section covers 5g tutorial basics which mentions need for 5g wireless, 5g technology features, advantages of 5g and key 5g projects as we know we can not live without modern wireless technologies. Difference between fdma, cdma and tdma i guess, one of the most basic questions which goes in our mind regarding telecom is what is the difference between the technologies which people generally talks about. Base stations are referred to as nodeb and control equipment for. The development of the cdma technique dates back to the early 1950s when. The receiver, knowing the code sequence of the user, decodes the received signal and recovers the original data. Manikas imperial college london ee303 communication systems. Dsss basics code division multiple access, cdma was an innovative use of direct sequence spread spectrum technology. The umts radio interface provides the basic definition of the radio signal. These have been created to support the effective delivery of a range of multimedia services. Principles of code division multiple access cdma professor a. Technical introduction to cdma course outline basic cdma principles coding forward and reverse channels cdma operational details multiplexing, forward and reverse. Pdf many digital cellular and mobile systems are in use today.
This allows several users to share a band of frequencies see bandwidth. Code division multiple access cdma has proven to be a viable enabling technique for the simultaneous transmission and. This is a brief tutorial that describes all the technical terms in a simple language to make it understandable for all the interested readers. Cdma technology has given significant advantages over other parallel technologies in terms of spectrum efficiency and overall performance. Cdma technology gave some significant advantages when compared to the technologies used for previous in cvma of overall performance and specifically in terms of spectrum efficiency. On comparing both the technologies gsm has some limitation when the call quality is concerned but still has more flexibility and an easy implementation relative to the cdma technology. Individual conversations are encoded with the help of pseudorandom digital sequence. The ds code is a signal generated by linear modulation with wideband pseudorandorn noise pn sequences. Communication systems following this concept are spread spectrum systems. Cdma basics orthogonal spreading codes cdma near far problem see also.
Cdma architecture cell breathing cdma is a noisegenerated technology. Cdma is a form of spreadspectrum, a family of digital communication techniques that have been used in military applications for many years. As such the system must monitor its noise floor or ambient noise. Basics idea about cdma technology and its applications. Code division multiple access cdma system in multipath. Difference between fdma, cdma and tdma learn about basics. The following section explains the basic concepts and ele ments of cdma. Code division multiple access cdma is a multiple access technology where the users are separated by unique codes, which means that all users can use the.
The technicality of cdma generation has given huge benefits over other parallel technology in terms of spectrum performance and. The technology is commonly used in ultrahighfrequency uhf cellular telephone systems, bands ranging between the 800mhz and 1. The pcs1900 licenses already cover approximately half of the us population, and it is. Cdma systems are equipment with a protocol that allows the system to adjust in these situations. Phil flikkemas usf briefing introduction to spread spectrum pdf about the capacity of a ds spread spectrum cdma cellular system pdf overview of modulation techniques for wireless pdf prof. Based on direct sequence spread spectrum technology, code division multiple access has been used in a variety of wireless systems including 3g. Cdma tutorial pdf, cdma online free tutorial with reference manuals and examples. Cdma signal spreading the very basics of how its done.
It is the technique by which same frequency and time interval is used by mobile subscribers base stations by way of unique digital codes. Fundamentals of communications access technologies. Code division multiple access cdma is a digital air interface standard, claiming eight to fifteen times the capacity of analog. It has a number of distinguishing features that are key to spread spectrum transmission technologies cdma technology basics tutorial. The major difference between the two lies in terms of. Code division multiple access technology mobile device investigations program technical operations division. This tutorial provides an introduction to basic gsm concepts, specifications, networks, and services. Analog cellular systems use frequency division multiple access fdma technique find, read and cite all the. With frequency division multiple access fdma, different signals are assigned frequency channels. This article is all about the difference between gsm and cdma technology. The umts world is an 3g mobile system news and information provider. As a result, ds cdma uses much wider signals than those used in other technologies.
Code division multiple access cdma has proven to be a viable enabling technique. Cdma is now defined by a number of standards, some of which are is95, jstd 008 pcs and. Fdma, tdma, cdma, ofdma, and sdma an introduction to the access technologies that allow multiple. Cdma codedivision multiple access refers to any of several protocols used in secondgeneration 2g and thirdgeneration 3g wireless communications. Cellular mobile telephone networks in australia use technologies.
Cdma technology filetype pdf wide band cdma technology is selected for utran air interface. Flexibility gsm is more flexible than cdma as wide range of phones can be used with this service. In code division multiple access cdma systems all users transmit in the same bandwidth simultaneously. Gps tracker label and label location details for fcc id 2aaq6ac05 made by mlabs technologies, llc. The goal of cdma is to break up a finite radio frequency so that multiple users can access it at the same time. Gsm and cdma are competing wireless technologies with gsm enjoying about an 82% market share globally. Giunta for the academic course of digital signal processing of the third university of rome rome, may 2000. Fdma is a basic technology in the analog advanced mobile phone system amps.
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