This document analyzes the simulation parameters of a pulse shaping FIR filter for WCDMA. It simulates a square root raised cosine pulse shaping filter in MATLAB Simulink with varying group delay parameters. The simulation measures the number of bits, number of errors, and bit error rate at different group delays. It finds that the bit error rate is minimized at a group delay of 6 symbol periods. The optimal values found are a group delay of 6 and a roll off factor of 0.22.
please if any problem in this slide than give me feedback i will remove those problem .
Two people can damage a society one who knows and does not talk, another one who does not know and talk.
please if any problem in this slide than give me feedback i will remove those problem .
Two people can damage a society one who knows and does not talk, another one who does not know and talk.
Weight enumerators of block codes and the mc williamsMadhumita Tamhane
Best possible error control codes of a certain rate and block length can be adjudged depending on bounds such that no codes can exist beyond the bounds and codes are sure to exist within the bounds. This presentation gives composition structure of Block codes and the probability of decoding error and of decoding failure.Mac William's Identities is relationship between weight distribution of a linear code and weight distribution of its dual code, which hold for any linear code and are based on vector space structure of linear codes and on the fact that dual code of a code is the orthogonal compliment of the code...
Design of Non-Uniform Linear Antenna Arrays Using Dolph- Chebyshev and Binomi...IJERA Editor
This paper explores the analytical methods of synthesizing linear antenna arrays. The synthesis employed is
based on non-uniform methods. In particular, the Dolph-Chebyshev and binomial methods are used, so as to
improve the directivity of the array and to reduce the level of the secondary lobes by adjusting the geometrical
and electric parameters of the array. The radiation patterns, the directivity, and the array factors of the uniform
and the non-uniform methods are presented. It is shown that the Chebyshev arrays have better directivity than
binomial arrays for the same number of elements and separation distance, while binomial arrays have very low
side lobes compared with Chebyshev and uniform excitation arrays. Finally, numerical results of both methods
are analyzed and compared.
Deterministic MIMO Channel Capacity
• CSI is Known to the Transmitter Side
• CSI is Not Available at the Transmitter Side
Channel Capacity of Random MIMO Channels
These slides deal with the basic problem of channel equalization and exposes the issue related to it and shows how it can be balanced by the usage of effective and robust algorithms.
Weight enumerators of block codes and the mc williamsMadhumita Tamhane
Best possible error control codes of a certain rate and block length can be adjudged depending on bounds such that no codes can exist beyond the bounds and codes are sure to exist within the bounds. This presentation gives composition structure of Block codes and the probability of decoding error and of decoding failure.Mac William's Identities is relationship between weight distribution of a linear code and weight distribution of its dual code, which hold for any linear code and are based on vector space structure of linear codes and on the fact that dual code of a code is the orthogonal compliment of the code...
Design of Non-Uniform Linear Antenna Arrays Using Dolph- Chebyshev and Binomi...IJERA Editor
This paper explores the analytical methods of synthesizing linear antenna arrays. The synthesis employed is
based on non-uniform methods. In particular, the Dolph-Chebyshev and binomial methods are used, so as to
improve the directivity of the array and to reduce the level of the secondary lobes by adjusting the geometrical
and electric parameters of the array. The radiation patterns, the directivity, and the array factors of the uniform
and the non-uniform methods are presented. It is shown that the Chebyshev arrays have better directivity than
binomial arrays for the same number of elements and separation distance, while binomial arrays have very low
side lobes compared with Chebyshev and uniform excitation arrays. Finally, numerical results of both methods
are analyzed and compared.
Deterministic MIMO Channel Capacity
• CSI is Known to the Transmitter Side
• CSI is Not Available at the Transmitter Side
Channel Capacity of Random MIMO Channels
These slides deal with the basic problem of channel equalization and exposes the issue related to it and shows how it can be balanced by the usage of effective and robust algorithms.
CDMA Transmitter and Receiver Implementation Using FPGAIOSR Journals
Abstract: Code Division Multiple Access (CDMA) is a spread spectrum technique that uses neither frequency channels nor time slots. With CDMA, the narrow band message (typically digitized voice data) is multiplied by a large bandwidth signal that is a pseudo random noise code (PN code). All users in a CDMA system use the same frequency band and transmit simultaneously. The transmitted signal is recovered by correlating the received signal with the PN code used by the transmitter. The DS - CDMA is expected to be the major medium access technology in the future mobile systems owing to its potential capacity enhancement and the robustness against noise. The CDMA is uniquely featured by its spectrum-spreading randomization process employing a pseudo-noise (PN) sequence, thus is often called the spread spectrum multiple access (SSMA). As different CDMA users take different PN sequences, each CDMA receiver can discriminate and detect its own signal, by regarding the signals transmitted by other users as noise- like interferences. In this project direct sequence principle based CDMA transmitter and receiver is implemented in VHDL for FPGA. Modelsim 6.2(MXE) tool will be used for functional and logic verification at each block. The Xilinx synthesis technology (XST) of Xilinx ISE 9.2i tool will be used for synthesis of transmitter and receiver on FPGA Spartan 3E. Keywords: CDMA, DSSS, BPSK, GOLD code.
Plastic manufacturing "forming and shaping plastics"Ayush Mathur
how plastic products are manufactured?
what are the processes involved in manufacturing of these products?
what are the various machine tools used?
what are the various types of plastics and what is resin?
what are the diffrent steps in manufacturing?
Get all these answers in this presentation.
introduction to pulse shaping and equalization in advanced digital communication, it's characterisation, signal design of band limited signal, design of bandlimited signal for no ISI and design of bandlimited signal with controlled ISI-partial response, linear equalization,
this is my prsentation of Plastic Process and Processing Parameter in manufacturing process. here discussed moulding process for plastic, plastic injection moulding, machine parts and procedure, material used to making mould and blow moulding process, thermoforming process, vacuum forming process, and application
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Analysis of Simulation Parameters of Pulse Shaping FIR Filter for WCDMAijsrd.com
The application of signal processing techniques to wireless communications is an emerging area that has recently achieved dramatic improvement in results and holds the potential for even greater results in the future as an increasing number of researchers from the signal process and communications areas participate in this expanding field. From an industrial viewpoint also, the advanced signal processing technology cannot only dramatically increase the wireless system capacity but can also improve the communication quality including the reduction of all types of interference. The present paper deals with simulation model of square root raised cosine pulse shaping filter for WCDMA with different parameters of the filter at 5Mhz.The present paper deals with study of Simulation Parameters (Number of Bits, Number of Errors) of Pulse Shaping FIR Filter at different value of group delay(2,4,6,8) to the calculate BER for WCDMA.
Orthogonal frequency-division multiplexing (OFDM)
[1] is a method of encoding digital data on multiple carrier
frequencies. OFDM[1] has developed into a popular scheme
for wideband digital communication, whether wireless or
over copper wires, used in applications such as digital television
and audio broadcasting, DSL Internet access, wireless networks,
powerline networks, and 4G mobile communications. In the
Several wireless standards such as IEEE 802.11a[2] and
HiperLAN2[3].The orthogonality of the subcarriers is no longer
maintained which results in ICI (Inter carrier Interference)[4]
.ICI reduction techniques achieve a better SNR and BER in
OFDM at zero phase noise variance . This technique will use a
large number of closely spaced orthogonal subcarriers to avoid
phase noise. It provides high data rates with sufficient robustness
to radio channel damages. A major problem in OFDM is carrier
frequency offset error between the transmitted and received
signals. Due to this the orthogonality of the subcarriers is no
longer maintained which results in ICI (Inter carrier
Interference). In this paper, we used the ICI self-cancellation
technique and reduced the ICI and improved the BER and SNR
we are also calculate the SNR=15db and 20db at different phase
noise variance.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
PERFORMANCE EVALUATION OF MC-CDMA SYSTEM OVER RAYLEIGH FADING CHANNELIJCSES Journal
Multi Carrier Code Division Multiple Access (MC-CDMA) is a well known technique for high speed
wireless data transmission .Two advanced technology was included in the MC-CDMA structure, such as
orthogonal frequency division multiplex (OFDM) and the code division multiple access (CDMA),so that it
benefits from the robustness of OFDM against multipath environment and from the capability of multiuser
multiplexing services that is achieved via (CDMA) system. MC-CDMA is a multicarrier spread spectrum
system which is classified as the candidate scheme for future mobile radio systems. In this paper MCCDMA
system, with Rayleigh fading channel and 16QAM array modulation, was simulated to investigate
the effects of different parameters on the system performance, such as processing gain; number of paths;
number of users; interleaving; and coding ratio.MC-CDMA performances can be considerably improved
by proper selection of these parameters. As expected, results show that MC-CDMA has a better performance over CDMA system.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
Abstract (11Bold) : — In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR. Keywords (11Bold) –64 QAM, BPSK, OFDM, PDF, SNR.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR
A significant problem in Multicarrier Code Division Multiple Access (MC-
CDMA) system is the possibility of high Peak to Average Power Ratio (PAPR). This is due
to the cumulative sum of N subcarrier peaks in the transmitted signals which reduces Power
efficiency, resolution and battery life. In this paper a technique is proposed to make use of
Inverse Discrete Cosine Transform (IDCT) and Inverse Discrete Wavelet Transform
(IDWT) based Multicarrier Code Division Multiple Access (MC-CDMA) system. This
system is in combination with Modified Exponential Companding with Clipping Transform
(MECCT) technique which reduces PAPR and that is analyzed over Additive White
Gaussian Noise (AWGN) channel, Rayleigh and Stanford University Interim (SUI)
multipath fading channel.
Performance of OFDM System under Different Fading Channels and Channel CodingjournalBEEI
Orthogonal frequency division multiplexing (OFDM) is a type of multicarrier modulation (MCM) technique in which larger bandwidth is divided into parallel narrow bands each of which is modulated by different subcarriers. All the subcarriers are orthogonal to each other and hence it reduces the interference among various subcarriers. OFDM technique is an efficient modulation technique used in certain wired and wireless application.In a wireless communication channel, the transmitted signal can travel from transmitter to receiver over multiple reflective paths. This results to multipath fading which causes fluctuations in amplitude, phase and angle of arrival of the received signal. For example, the signal which is transmitted from BTS (base transceiver station) may suffer multiple reflections from the buildings nearby, before reaching the mobile station. Such multipath fading channels are classified into slow fading/fast fading and frequency-selective/flat fading channels. This paper discusses the performance of OFDM system using various fading channels and channel coding. The parameter which is known as Bit error rate (BER) is calculated under different fading channels (AWGN, Rayleigh and Rician) for different digital modulation (BPSK, QPSK and QAM) and Channel coding (linear/Cyclic coding). Matlab Simulink tool is used to calculate the BER parameter.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
1. Analysis of Simulation Parameters of Pulse Shaping FIR
Filter for WCDMA
Digital Signal Processing
And
Digital Communication
2. Analysis of Simulation Parameters of Pulse
Shaping FIR Filter for WCDMA
THE PROJECT DEALS WITH SIMULATION MODEL OF SQUARE ROOT RAISED
COSINE PULSE SHAPING FILTER FOR WCDMA WITH DIFFERENT
PARAMETERS OF THE FILTER AT 5MHZ. IT DEALS WITH STUDY OF
SIMULATION PARAMETERS (NUMBER OF BITS, NUMBER OF ERRORS) OF
PULSE SHAPING FIR FILTER AT DIFFERENT GROUP DELAY FOR WCDMA.
3. Introduction about WCDMA
Digital Signal processing techniques are being used to improve the performance of 3G systems. WCDMA
(Wideband Code-Division Multiple Access), an ITU standard derived from Code-Division Multiple Access
(CDMA), is officially known as IMT-2000 direct spread spectrum.
W-CDMA is a third-generation (3G) mobile wireless technology that promises much higher data speeds to
mobile and portable wireless devices. W-CDMA can support mobile/portable voice, images, data, and video
communications at up to 2 Mbps (local area access) or 384 Kbps (wide area access).
W-CDMA is one of several methods of multiplexing wireless users. In CDMA, users are multiplexed by
distinct codes rather than by orthogonal frequency bands, as in frequency-division multiple access.
4. Contd…
The information is spread over a band of approximately 5 MHz. This wide bandwidth has given rise to the name
Wideband CDMA or WCDMA.
In WCDMA, the CDMA technology (Code Division Multiple Access) air interface is implemented along with
GSM networks. WCDMA is a Third Generation (3G) technology and works towards the interoperability between
the various 3G technologies and networks being developed worldwide. WCDMA transmits on a 5 MHz wide radio
channel and hence is called Wideband CDMA. This 5 MHz wide radio channel is in contrast to CDMA which
transmits in one or more pairs of 1.25 MHz wide radio channel. WCDMA uses Direct Sequence spreading
spectrum (DSSS), where spreading process is done by directly combining the baseband information to high chip
rate binary code. The Spreading Factor is the ratio of the chips (Universal Mobile Telecommunication System,
UMTS = 3.84Mchips/s) to baseband information rate.
5. Need of efficient Pulse Shaping
In communications systems, two important requirements of a wireless communications channel demand the
use of a pulse shaping filter. These requirements are:
1)
Generating band limited channels
2)
Reducing inter symbol interference
Both requirements can be accomplished by a pulse shaping filter which is applied to each symbol. In fact, the
sync pulse, meets both of these requirements because it efficiently utilizes the frequency domain to utilize a
smaller portion of the frequency domain.
6. Contd…
The sinc pulse is periodic in nature and it has maximum amplitude in the middle of the symbol time.
It appears as a square wave in the frequency domain and thus can effectively limit a communications channel to a
specific frequency range.
7. Contd…
A.
Reducing Channel Bandwidth
Modulation of a carrier sinusoid results in constant transitions in its phase and amplitude. Below, figure shows the
time domain of a carrier sinusoid with a symbol rate that is half
of the carrier. It is clear that phase/amplitude transitions occur at
every two periods of the carrier and sharp transitions occur, when
filtering is not applied. The sharp transitions in any signal result
in high-frequency components in the frequency domain. By
applying a pulse shaping filter, the sharp transitions are smoothed
and the resulting signal is limited to a specific frequency band.
8. Contd…
Fig shows smoothed phase and amplitude transitions in a filtered modulated signal. It happens much more gradually
when filtering is implemented. As a result, the frequency information of the sinusoid becomes more concentrated into
a specified frequency band. The sharp transitions do cause high frequency components in the frequency domain.
Now, once a filter has been applied to the carrier signal,
These high frequency components of the signal have been
removed. Thus, the majority of the channel power is now
limited to a specific defined bandwidth. It is clear that the
required bandwidth for a channel is directly related to the
symbol rate and is centered at the carrier frequency.
9. Contd…
B. Reducing Inter-Symbol Interference (ISI)
In band limited channels, intersymbol interference (ISI) can be caused by multi-path fading as signals are transmitted
over long distances and through various mediums. This characteristic of the physical environment causes some
symbols to be spread beyond their given time interval. As a result, they can interfere with the following or
preceding transmitted symbols. To solve this problem we apply the pulse shaping filter. By applying this filter to
each symbol that is generated, it is possible to reduce channel bandwidth while reducing ISI. Fig (A) shows the
output in time domain. It is clear that the maximum amplitude of the pulse-shaping filter occurs in the middle of the
symbol period. In addition, the beginning and ending portions of the symbol period are attenuated. Thus, ISI is
reduced by providing a pseudo-guard interval which attenuates signals from multipath reflections.
11. Raised Cosine Filter
If the transmitted signal is restricted to a certain bandwidth, then infinite bandwidth associated with a rectangular
pulse is not acceptable. The bandwidth of the rectangular pulse can be limited, however, by forcing it to pass through
a low-pass filter. The act of filtering the pulse causes its shape to change from purely rectangular to a smooth contour
without sharp edges. This filter is the well-known raised cosine filter and its frequency response is given by
H(w)= τ…………………………….0≤w≤c
τ{cos2[τ(w-c)/4α]}…………c≤w≤d
0…………………………….w>d
where w is the radian frequency 2πf, τ is the pulse period, α is roll off factor, c is equal to π(1-α)/τ , d is equal to
π(1+α)/τ.
13. Square Root Raised Cosine Filter
The frequency Response of the Square-Root Raised Cosine is given as below.
H(w)=√τ…………………………….0≤w≤c
√τ{cos[τ(w-c)/4α]}…………c≤w≤d
0…………………………….w>d
The consequence of pulse shaping is that it distorts the shape of the original time domain rectangular pulse into a
smoothly rounded pulse with damped oscillations (ripples) before and after the ½ To points. The ripples result from
the convolution of the rectangular pulse with the raised cosine impulse response (convolution is the process of
filtering in the time domain). Reduced bandwidth means larger ripple, which exacerbates ISI and increases the
likelihood of an incorrect decision (that is, error) at the receiver.
15. Pulse Shaping in WCDMA
Code-division multiple access is one of several methods of multiplexing wireless users. In CDMA, users
are multiplexed by distinct codes rather than by orthogonal frequency bands, as in frequency-division
multiple access.
The processing gain factor is defined as the ratio of the transmitted bandwidth to information bandwidth
and is given by:
Gp=Bt/Bi
Correlating the received signal with a code signal from a certain user will then only despread the signal of
this user, while the other spread-spectrum signals will remain spread over a large bandwidth.
16. Simulation model of WCDMA
The performance in terms of the Bit Error Rate can be examined for different values of Group Delay
“D” of the pulse shaping filter against a sinusoidal interference.
The information signal in wideband CDMA system is generated by Bernoulli Binary Generator and the
PN sequence is used for spreading the signal at certain bandwidth.
The signal is passed from different parameters block and at the end BER is calculated by comparing the
transmitted data and received data.
On the basis of block diagram, a simulation model will be developed by using Matlab Simulink.
19. Description of all elements used in SIMULINK model
Bernoulli Binary Generator: Bernoulli Binary Generator is used to generate information signal appropriate with
the standard for WCDMA from simulink library. Bernoulli Binary Generator block as shown in figure generates
random binary numbers using Bernoulli Distribution. The Bernoulli distribution has mean value=(1-p) and
variance=p(1-p).The probability of a zero parameter specifies p and can be any real number between zero and one.
PN Sequence Generator: The PN Sequence is produced by pseudo random noise generator that is simply a
binary linear feedback shift register consisting of XOR gates and a shift register. This PN Sequence has the ability
to create an identical sequence for both transmitter and receiver and yet retaining the desirable properties of a
noise like randomness bit sequence. In Direct Sequence Spread Spectrum System, to generate a chip rate of
3.84Mbps for 5Mhz bandwidth in WCDMA system PN Sequence Generator has been used.
20. Contd…
Data Type Conversion Block: It converts input to data type and scaling of output. This conversion has two
possible goals. One goal is to have real world values of input and output be equal. Other goal is to have stored
integer values of input and output be equal. Overflows and Quantization errors can prevent goal from being fully
achieved.
XOR Logical Operator: For single input operators are applied across input vector. For multiple inputs operators
are applied across inputs.
Differential Encoder: It differentially encodes the input data. The output of this block is a logical difference
between present input to this block and previous output of this block. The input can be a scalar, vector or frame
based matrix.
21. Contd…
Modulator baseband: It modulates the input signal using the offset quadrature phase shift keying (OQPSK) method.
The input can be either bits or integers. For sample based integer input, input must be a scalar. For frame based integer
input, input must be a column vector. In case of sample based input, output sample time equals symbol period divided by
2. There are different variants such as QPSK, orthogonal QPSK (OQPSK).
BFFT Scope: This spectrum scope computes and displays the periodogram of each input signal. Non frame based inputs
to this block should use buffering option.
Upsampling Block: It upsamples the integer sampling rate by a factor of 8.
Square Root Raised Cosine Transmit Filter: It upsamples and filters the input signal. The group delay is specified as
the number of symbol periods between start of filter response and its peak. This delay also determines the length of filter
impulse response which is 1+2*N*Group Delay.
22. Contd…
dB Gain: Here we apply the amplitude gain specified in dB. Here 5dB and 10 dB gain have been taken in present
study for subsequent analysis.
Gaussian Noise generator: It generates the Gaussian distributed noise with given mean and variance values.
AWGN Channel: It adds white Gaussian noise to the input signal. The input and output signals can be real or
complex. This block supports multichannel input and output signals as well as frame based processing. Here in
AWGN channel block, we can change Eb/No from 5dB to 10dB.
Square Root Raised Cosine Receive Filter: It filters the input signal and downsamples using Square root raised
cosine FIR filter. The group delay is specified as the number of symbol periods between start of filter response and
its peak. This delay also determines the length of filter impulse response which is 1+2*N*Group Delay.
23. Contd…
Downsampling Block: It downsamples the input sample rate by integer factor of 8.
Demodulator Baseband: It demodulates the input signal using the offset quadrature phase shift keying (OQPSK)
method. The input can be either bits or integers. For sample based integer input, input must be a scalar. For frame
based integer input, input must be a column vector. In case of sample based input, output sample time equals
symbol period divided by 2. This block has variants such as QPSK, orthogonal QPSK.
Differential Decoder: It differentially decodes the input data. The output of this block is a logical difference
between present input to this block and previous input of this block. The input can be a scalar, vector or frame
based matrix.
Unit Delay: It samples and hold with one sample period delay.
24. Contd…
Error Rate Calculation Block: It computes the error rate of received data by comparing it to the delayed version
of transmitted data. The block output is a three element vector consisting of error rate followed by number of
errors detected and total number of symbols compared.
Display: It is for the numeric display of values input to it from error rate calculation block. Here one can get data
display in different formats.
29. Results
The simulation study has also been carried out for different values of D i.e.2,4,6 and 8.
The readings of the simulation model for number of bits, number of errors and Bit Error Rate at different values of
D have been taken at different time instants during the simulation runs. The parameters of the simulation model
are given as below:
1.
Eb/No=5dB
2.
PN Sequence Generator Sample time=1/3840kbps
3.
Bernoulli Binary Generator Sample time=1/64kbps(data services)
4.
Interpolation Factor M=5
5.
Roll Off Factor =0.22(Optimum)
It is also observed that BER decreases as the group delay is increased from 2 to 4 and then from 4 to 6. The BER
is found to increase as the value of group delay D is varied from 6 to 8. Hence the group delay should be
controlled at D=6 by RF design engineer. Hence the optimum value of D=6 is taken for subsequent analysis in
WCDMA system.
31. Conclusions
The present study has proposed the WCDMA communication link employing the pulse shaping filters using
matlab simulink. The group delay (D) plays a crucial role in pulse shaping digital finite impulse response filter.
The value of group delay should be minimal for efficient performance of digital pulse shaping filter. The effects of
change in group delay on number of errors have been studied for square root raised cosine pulse shaping filter at 5
MHz band The effect of variation of group delay D i.e. number of symbols spanned by impulse response is studied
at fix value of Roll Off Factor (alpha)=0.22 as well as at fix value of interpolation M=5. The study has impact on
analysis & simulation of pulse shaping families in WCDMA based wireless communication system.
32. Contd…
The study will be useful to improve the performance of WCDMA based network by using the modified and
improved design of square root raised cosine pulse shaping filter. Design of new type of filter of higher or
different order will be useful to get better root raised cosine approximation thereby improving the performance
parameters like increased Capacity, reduced BER, better S/N ratio, and Reduced ISI (noise) as a consequence of
pulse shaping. The future work will involve the incorporation of interpolation factor for tradeoff between D and M
at fix roll off factor as well as study of parameters of pulse shaping filter on the bit error rate performance analysis
for WCDMA based wireless communication.
33. References
Simon Haykin, “Communications Systems” , Tata McGraw Hill.
B.P. Lathi, Modern Digital and analog Communications Systems, John Wiley & Sons.
John G. Proakis, Digital Communications. McGraw Hill.
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5044827&url=http%3A%2F%2Fieeexplore.ieee.org%2Fx
pls%2Fabs_all.jsp%3Farnumber%3D5044827
http://www.ijcaonline.org/archives/volume40/number8/4981-6675
http://www.mathworks.in/help/comm/ug/digital-modulation.html