There are exceptions with respect to the modulation quality and frequency error. Gsm is type of service provided in mobile handset in which all the network can be use like tmobile,fido,vodafone,etc. Pdf comparative analysis of various digital modulation. Wcdma signal eer wcdma signal is both amplitude and phase modulated contains am of cdma signal. It uses a 5 mhz wide radio signal and a chip rate of 3. As qpsk is used for the modulation of the syncdl, the phases 5, 45, 225, 5 and 315, 225, 315, 45 are used. It is the most widely used technology in the world for mobile phone communications. There are several considerations that were taken into account when making the choice for the overall format for the umts wcdma modulation formats. Due to coherent modulation, each users uplink requires an individual channel estimation. Which modulation types are being used in gsm and its. Difference between wcdma and lte compare the difference. Developed and maintained by the 3gpp 3rd generation partnership project, umts is a component of the international telecommunications union imt2000 standard set and compares with the cdma2000 standard set for networks based on the competing cdmaone. International journal of computer networking and communication ijcnacvol.
Third generation wcdma radio evolution wiley online library. Applying spread spectrum modulation techniques to cellular communications allows for multiple users to share common spectrum. Elements of a wireless network electrical engineering and. The utran air interface uses qpsk modulation in the downlink, although hsdpa may also employ 16 quadrature amplitude modulation 16qam. Eer separates the cdma signal into two new signals signal decomposition. The following section derives the correction factor for a wcdma signal using ads simulation fig. Performance investigation for different modulation.
Rf lecture series modulation fundamentals introduction to wcdma. One modulation technique that lends itself well to digital processes is called iq modulation, where i is the inphase component of the waveform, and q represents the quadrature component. Performance evaluation of digital modulation techniques on. If original signal is xt of power ps, and the code sequence is given by gt, the resultant modulated signal is st 2ps dtgt the multiplication of the data sequence with the spreading sequence is the first modulation. Meassetup w cdma3gpphspa demod properties channellayer tab default. In the wcdma multi evaluation application, the user needs to configure the scenario so that the combined signal path, is controlled by wcdma sig1 in order to automatically align the signal routing and analyzer settings with the signaling configurations.
The first is the channelization operation, which transforms every data symbol into a number of chips, thus increasing the bandwidth of the signal. The coefficients of the second order product in the model is. Modulation scheme chooses how the vsa demodulates the hs pdsch high speed physical downlink shared channel corresponding to one channelization code of fixed spreading factor equal to 16. The total number of phase quadruples is 2 s1 and s2. Trf370417 50mhz to 6ghz quadrature modulator datasheet rev. Ip2 and ip3 nonlinearity specifications for 3gwcdma receivers. Digital modulation in communications systems an introduction. Making the modulation accuracy composite evm measurement.
It is necessary to ensure that the data is carried efficiently over the available spectrum, and therefore maximum use is made of the available spectrum, and hence the. Cdma is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. Amplitude signal 0 phase signal 0 0 wcdma signal eer wcdma signal is both amplitude and phase modulated contains am of cdma signal contains pm of cdma signal baseband signal, dc to 30mhz phase modulated carrier at rf envelope elimination envelope. Qualcomm still makes chips for wcdma, cdma, and gsm, but it is pushing for older generations for. Cdma, code division multiple access an implementation of direct sequence spread spectrum, dsss, and was used almost universally for 3g mobile communications standards as it provided an excellent format as a multiple access scheme. High data rate signal transmission can be transmitted over the air by using w cdma system, thus enabling video streams and high resolution pictures to end users. Signal spaces and basis functions study of signal spaces provides us with a geometric method of conceptualizing the modulation process. Gsm is used to handle both voice and data traffic requirements of the mobile communication.
The composite evm measurement is a modulation accuracy against the multi coded reference symbol power through the spreading and scrambling circuits. Third generation wcdma radio evolution harri holma,y and antti toskala nokia networks, ip mobility networks, po box 301, fin00045 nokia group, finland summary third generation partnership project 3gpp produced the. Note that a free running rf generator provides the lo signal. However, nokia and erickson have just signed an agreement with tmobile to upgrade to 3 rd generation wcdma from gsm. The suitability of digital modulation techniques to cdma are tested. With cw signal, rx noise level is often about 5dbmhz. Wcdma wideband code division multiple access and lte long term evolution are mobile communication technologies that falls under the 3rd generation partnership project 3gpp releases.
Within the wcdma signal format of umts a number of different forms of actual modulation can be used 3g umts includes. An99 lt5528 wcdma acpr, altcpr and noise measurements. Wideband code division multiple access wcdma is being used by universal mobile telecommunication system umts as platform of the 3rd generation cellular communication system. Digital modulation an overview sciencedirect topics. This type of generator is used because of its superior noise performance. Matlab and simulink based simulation of wideband code division multiple access wcdma 64. Spreading and modulationspreading and modulation synchronization channel spreading and modulation primary and secondary sch primary sch contains a code word with 256 chips identical in every cell secondary sch code word varies from one bs to another of total 64 code words. Rho is the ratio of the correlated power in a multi coded channel to the total signal power. The lower forms of modulation, qpsk do not require such a large signal to noise ratio but are not able to send the data as fast. Wideband code division multiple access wcdma was introduced to provide higher data rates in mobile communication. The performance of wcdma system in awgn channel shows that bpsk modulation technique has a better performance compared to that of qpsk and 16qam.
Only when there is a sufficient signal to noise ratio can the higher order modulation format be used. Key method we have considered two modulation techniques of quadrature amplitude modulation qam and quadrature phase shift keying qpsk used in wcdma systems. Gprs general packet radio service 144 kbps data only. Gsm is an open, digital cellular technology used for transmitting mobile voice and data services. As the frequency offset gets close to edge of frequency band, spectrum regrowth dominates these specifications rather than noise. There are three basic ways to modulate a carrier signal in a digital sense. One is a cw tone and the other is a modulated wcdma carrier. Digital modulation types and relative efficiencies 3.
To view the scopes in real life, one can doubleclick the icons when the simulation is running. The two tone test case and the case of single tone plus wcdma uplink signal test case are simulated. This excludes modulation techniques like frequency modulation fm and phase modulation pm. Wcdma wideband cdma proposed by european telecom std inst etsi alpha group wcdma has 5mhz single carrier system w freq div duplexing and direct sequence fddds. Then the signal is multiplied by the carrier which is the second modulation. Higher orders of modulation allow us to encode more bits per symbol or period time. Thanks to data compression algorithms, a digital signal carrying voice data can take up less rf bandwidth then an analog voice signal. Lte standards are part of the latest 3gpp releases, which are considered as 4th generation 4g, and wcdma is the older technology which was specified as 3rd. Ip2 and ip3 nonlinearity specifications for 3gwcdma. Matlab and simulink based simulation of wideband code. However, with signal of 12rb and qpsk modulation in 10mhz band, rx noise level will be dramatically increased. The proposed 3g wideband cdma systems are complex in nature. Wcdma, known primarily as 3g mobile, is a family of 3g data protocols used to send voice, text and signaling data to smart phones and other wireless devices. The exact lte modulation format is chosen depending upon the prevailing conditions.
Performance evaluation of digital modulation techniques on ds. In particular, we discuss amplitude and frequency modulation. Second generation cellular cdma systems use what is called dual. Codedivision multiple access cdma is a channel access method used by various radio communication technologies. High data rate signal transmission can be transmitted over the air by using wcdma system, thus enabling video streams and high resolution pictures to end users. Wcdma uplink physical channel uplink data is carried on the dedicated physical data channel dpdch and different data rate is realized using different spreading factor. In a physical space when we describe a vector by its coordinates x, y. The performance of bpsk,qpsk and 16qam modulation technique in w. Overrides the automatic modulation detection and lets you specify the downlink hs pdsch or the uplink edpdch modulation scheme, to be used with the despread code channel for channel measurement results. Wcdma rf measurement with cmw500 according to 3gpp ts 34. As seen, with 16qam also the amplitude of the signal matters.
Developed and maintained by the 3gpp 3rd generation partnership project, umts is a component of the international telecommunications union imt2000 standard set and compares with the cdma2000 standard set for networks based on the competing. Signal the following scopes in fig 4 display the signal in various ways. A datamodulation scheme defines how the data bits are mixed with the carrier signal, which is always a sine wave. Wcdma spreading and modulation stanford university. Wcdma provides the ability to dynamically assign data rates and modulation format to match the individual user demand. Jul, 2011 wcdma wideband code division multiple access and lte long term evolution are mobile communication technologies that falls under the 3rd generation partnership project 3gpp releases. Multilevel simulation of wcdma systems for thirdgeneration. In case the presence of a pccpch is indicated, the next following subframe is the first subframe of the interleaving period. Wideband code division multiple access wcdma is a thirdgeneration 3g standard that employs the directsequence code division multiple access dscdma channel access method and the frequencydivision duplexing fdd method to provide highspeed and highcapacity service.
What is wideband code division multiple access wcdma. Why wcdma wcdma is a step further in the cdma technology. The universal mobile telecommunications system umts is a third generation mobile cellular system for networks based on the gsm standard. Rho is one of the key modulation quality metrics, along with evm and code domain power. Coverage of wcdma network using different modulation techniques with soft and hard decision decoder j. Codedivision multiple access cdma techniques using direct sequence ds spread spectrum techniques were embodied in the is95a cellular standard and are now the clearly accepted choice for thirdgeneration cellular 3g and pcs applications. Wcdma multi evaluation config measurement control modulation cdp. Within the wcdma signal format of umts a number of different forms of actual modulation can be used. In its various forms, iq modulation is an efficient way to transfer information, and it also works well with digital formats. What is umts network architecture radio access radio interface frequency bands umts cdma modulation data channels umts tdd tdsdcdma handover. Rf lecture series modulation fundamentals introduction to. This is critical, as a noisy lo signal may corrupt the modulator output, and consequently the acpr. Modulation modulation is the process by which a carrier wave is able to carry the message or digital signal series of ones and zeroes. This and the data transport format is carried on thededicated physical.
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