Essay About NT1230 Chapter 7 Questions

Essay about NT1230 Chapter 7 Questions
NT1210
11/13/2013
Chapter 7
1. A user of a home telephone picks up her phone and makes a telephone call to a friend's home telephone in another part of town. Which of the
following is likely to be true about this call?
A. It uses a single pair of wires on the local loop at each end of the call
2. Which of the following are services that telcos have offered as WAN services over the years?
A. Switched analog circuits
B. Dedicated digital circuits
3. This chapter claims that IP routers work well as devices that connect to many different types of interfaces, including LANs and WANs. Which of the
following answers list the reasons why routers do well in this role?
A. Routers have much faster CPUs and can do the hard work to ... Show more content on Helpwriting.net ...
Which of the following answers lists other physical parts that the customer will need for that sites installation of the T1 leased line?
B. A serial cable
8. A telco customer has a T1 leased line between two sites, called sites A and B. the telco has several switches between sites A and B that use T3
trunks. These switches use the T3 trunks along with time–division multiplexing (TDM) to create the leased line from site A to B. which of the
following answers is true about how TDM works in this design?
C. The switches map the T1 customer lines to one of 28 different frequencies in the T3 trunks
9. A telco network has TDM switches in the CO, ready to support T1 leased lines to customer sites. Two such switches have a single T3 trunk
connecting the two switches, set aside to support T1s that run just between those two CO switches. Which of the following answers best describes the
number of customer T1s the telco can support with these switches and the trunk?
C. 28
10. A customer ordered a full T1 leased line between two sites. The telco implemented that leased line in its network using theT–carrier technology
discussed in this chapter, with DS1, DS2, and DS3 lines plus switches that use time–division multiplexing (TDM) logic. Into which of the following
general WAN categories does this service fit?
B. Packet switching
11. A telco customer orders a leased line

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Applying A New Localization Approach Based On...
пїјA fine–grained Indoor Localization using Multidimensional WiFi Fingerprinting
Abstract–Although fingerprint based localization is promising for indoor applications, its accuracy remains a huge challenge. Most existing approaches
depends on the Radio Signal Strength (RSS) to generate fingerprints. Merely using RSS is unable to accurately localize since such an one–dimensional
fingerprint is serious influenced by the interference and multipath effect in the indoor environment. In this paper, we propose a new localization
approach based on multidimensional WiFi fingerprint. Instead of using RSS only, we employ RSS, transmitted power, and channel information to
construct fingerprints. The extension of fingerprints enables fine–grained localization and tracking services. We also deign a cosine similarity based
matching algorithm and enhanced particle filter mechanism to realize the localization and tracking. Extensive experiment and implementation results
show that using the new fingerprint can achieve an accuracy within 2m in 90% testing points, with good adaptability to complex indoor environments.
Keywords–Indoor positioning; Multidimensional fingerprint; WIFI. Fingerprint matching
I. INTRODUCTION
Accurate indoor localization is crucial for many applications, such as the navigation, tour guiding, escaping, etc. Different from outdoor localization,
which mainly depends on the global positioning system (GPS), providing accurate positioning service is difficult in the indoor

Orthogonal Frequency Division Multiplexing
Orthogonal Frequency Division Multiplexing or OFDM is a modulation format that is being used for many of the latest wireless and
telecommunications standards.
OFDM has been adopted in the Wi–Fi arena where the standards like 802.11a, 802.11n, 802.11ac and more. It has also been chosen for the cellular
telecommunications standard LTE / LTE–A, and in addition to this it has been adopted by other standards such as WiMAX and many more.
Orthogonal frequency division multiplexing has also been adopted for a number of broadcast standards from DAB Digital Radio to the Digital Video
Broadcast standards, DVB. It has also been adopted for other broadcast systems as well including Digital Radio Mondiale used for the long medium
and short wave bands. ... Show more content on Helpwriting.net ...
The resulting signal is integrated over the symbol period to regenerate the data from that carrier. The same demodulator also demodulates the other
carriers. As the carrier spacing equal to the reciprocal of the symbol period means that they will have a whole number of cycles in the symbol period
and their contribution will sum to zero – in other words there is no interference contribution.
The spectrum of an OFDM, orthogonal frequency division multiplexing signal
OFDM Spectrum
One requirement of the OFDM transmitting and receiving systems is that they must be linear. Any non–linearity will cause interference between the
carriers as a result of inter–modulation distortion. This will introduce unwanted signals that would cause interference and impair the orthogonality of
the transmission.
In terms of the equipment to be used the high peak to average ratio of multi–carrier systems such as OFDM requires the RF final amplifier on the
output of the transmitter to be able to handle the peaks whilst the average power is much lower and this leads to inefficiency. In some systems the
peaks are limited. Although this introduces distortion that results in a higher level of data errors, the system can rely on the error correction to remove
them.
Data on OFDM
The data to be transmitted on an OFDM signal is spread across the carriers of the signal, each carrier taking part of the payload. This reduces the data
rate taken by each carrier. The lower data rate has

Telecom Assignment
Assignment 5
1. A LAN has a data rate of 4 Mbps and a propagation delay between two stations at opposite ends of 20 Ојs. For what range of PDU sizes does
stop–and–wait give an efficiency of at least 50%?
r = 4 d = 20 E > 0.5
The equation should look like: Range = 2 * 20 * 10^–6 * 4 * 10^–6 which is =
0.00000000016 or 160 bits
2. A disadvantage of the contention approach for LANs is the capacity wasted due to multiple stations attempting to access the channel at the sametime.
Suppose that time is divided into discrete slots, with each stations attempting to transmit with probability p during each slot. What fraction of slots are
wasted due to multiple simultaneous transmission attempts?
The fraction of slots ... Show more content on Helpwriting.net ...
Therefore, we have:
Vulnerability Period = (transmission time + propagation delay) = 100/1 x 106 + 1 x 103/2 x 108 = 0.000105 sec
Probability of one or more packet arrivals at one of the stations = 1 – e–О» (vulnerability period) = 0.65
a. Slot Time = Transmission Time and Propagation Time
Transmission Time = (Number of bits / Rate)
Propagation Rate = 200,000,000 m / Second
Slot Rate = 1 / slot time = 100 bits per slot
Propagation Time = (10^4 / 2)(10^8) = 50 Вµs propagation delay
Transmission Time = (100 bps/10,000,000 bps) = 10 Вµs

Slot Time = 10Вµ seconds + 50 Вµ seconds = 60 Вµs
Slot Rate = (1 / .00006) = 16,666.7
Data Rate = (1,000 x 16,666.7) = 16666700Mbps
b. The duration of one bit delay = [(1 bit/ T seconds)=(10,000,000 bits / 1 second )], therefore, T= 0.1ms
So, one bit delay is imposed by (N+2) x 0.1 ms.
The propagation delay = 2d x (20ms/km) = (2x10) x (20ms/km) = 0.4 seconds or 400 ms.
But per the question, we need to use (2 x 10^8 m/s) for the propagation delay.
Transmission Time= [(100 bit/t seconds) = (10,000,000 bits / 1 second)] Therefore, t = 10 ms
Each 100–bit packets requires 10ms+(2 x 10^8)+(N+2) x 0.1

Wireless Communication Essay
OVERVIEW:
In the last few years, number of mobile users/wireless users has been increased explosively all over the world. The demands for wireless
communication network has been increased day by day and it cannot be satisfied with wired networks because it has been seen that communication
channels are more contaminated than wired networks. The main characteristics of the wireless communication are the multipath reception. We can
receive signal not only through Line of Sight but also reception can be made through a large number of reflected radio waves that arrive at the
receiver at different times. The difference in arrival time is caused due to trees, vehicles, buildings, rocks etc. FIGURE1: MULTIPATH
PROPAGATION [5]
These reflected waves interfere with the direct coming received wave and the other ... Show more content on Helpwriting.net ...
Robustness Against Narrowband Interference:– OFDM is more robust then single carrier against narrowband interference because in a single carrier
system, a single fade or interferer can cause the entire link to fail and the transmission would stop[5]but in a multicarrier system, only a small
percentage of subcarriers will be affected and transmission would be possible in that case also. Immune to Frequency Selective Fading:– OFDM is
highly immune to frequency selective fading channel as parallel transmission as each sub–carrier has narrow bandwidth in comparison to overall
bandwidth of signal. Hence it converts a frequency selective fading channel into several nearly flat fading channels. High Spectral Efficiency:– Due to
orthogonal nature of each sub–carrier, large number of subcarriers can be accommodate over a very narrow spectral region thus it increases the spectral

Optical Optic Communications Link For Aircraft
ABSTRACT
This paper demonstrates a fiber optic communications link for aircraft that utilizes wavelength division multiplexing (WDM) to avionics environment
to support multiple analog RF signals transmission simultaneous over single optical fiber. This paper investigates the simultaneous transmission of two
RF signals over a single optical fiber. The transmission of FM and AM analog modulated signals, and also FSK digital modulated signals, over a fiber
optic link (FOL) employing wavelength division multiplexing is determined. We present data from measurements of power loss, total harmonic
distortion (THD), signal–to–noise ratio (SNR), delay, carrier–to–noise ratio (CNR), and bit error rate (BER).The results indicate that wavelength
division multiplexing is a fiber optic technology appropriate for avionics applications.
INTRODUCTION
During flight, aircraft avionics transmit and receive Radio Frequency signals from/to antennas over coaxial links. The electromagnetic interference
(EMI) environment corrupts proportionately, as the density and complexity of onboard avionics increases, which prompts diminish in signal–to–noise
ratios (SNRs) and potential safety concerns. Existing coaxial cable–based systems cannot be implemented for a network with simple, dependable, and
lightweight which is free from the impacts of electromagnetic interference and fit for supporting the broadband communications needs of future
installed computerized aeronautics systems. A

System Performance Improvement For Ofdm System Over...
SER Performance Improvement in OFDM System over Generalized K–Fading Channel
Keerti Tiwari, Bindu Bharti and Davinder S. Saini
Department of Electronics and Communication Engineering
Jaypee University of Information Technology
Waknaghat, Solan (H.P.)–173234, India krt.tiwari@gmail.com, bindu.bharti457@gmail.com, davinder.saini@juit.ac.in
Abstract– In this paper, performance metric of orthogonal frequency division multiplexing (OFDM) system is analyzed over a composite fading
channel i.e. generalized K– fading channel. Here, OFDM system is considered which include repetition code to enhance the wireless link performance
with simplicity. Symbol error rate (SER) performance is evaluated using binary phase shift keying (BPSK) and 16–qardature amplitude modulation
(16–QAM) over generalized–K fading channel. This channel model considers Nakagami–m distribution to define multipath and gamma distribution to
represent shadowing. Simulation results demonstrate that improved system performance can be achieved using repetition code in severely faded
environment. A comparative study of coded and uncoded system is also given in this paper. Consequently, SER performance is improved with the
increase in shape parameters.
Keywords– Orthogonal frequency division multiplexing (OFDM), Generalized K–fading, binary phase shift keying (BPSK), 16–qardature amplitude
modulation (16–QAM), symbol error rate (SER). Introduction
Next generation wireless technologies have demanded efficient and

The Importance Of Multicarrier Techniques For A Single...
Chapter 1 Multicarrier techniques
This section deals with the importance of multicarrier techniques.
1.1 Multi carrier techniques
In a single carrier system, single fade causes the whole data stream and undergo distortion i.e frequency selective fading. The Single carrier systems also
suffer with heavy Inter Symbol Interference . In telecommunication Inter Symbol Interference was a form of distortion of signal in which one symbol
interferes with the subsequent symbol. Thus it causes an unwanted phenomena as the previous symbols have similar effect as noise thus making
communication less reliable . ISI occurs when the signal bandwidth is less than the coherence bandwidth or when the delay spread is greater than
symbol duration. To combat the problem multicarrier techniques have been proposed for high data rate transmission. Multicarrier techniques divide the
whole bandwidth into large number of narrow band orthogonal subcarriers [1, 2]. Thus the signal bandwidth becomes very less compared with
coherence bandwidth ensuring no ISI in time domain and flat fading in frequency domain. Multicarrier systems such as Orthogonal Frequency Division
Multiplexing (OFDM) and Multi Carrier Code Division Multiple Access (MC–CDMA) were considered to be the best technologies for 4G wireless
communication [1, 2]. Fig. explains the spectrum of multicarrier and single carrier systems. In the single carrier system the information symbols are
loaded into one of

Investigated The Characteristics Of ( EDFA ) Erbium Doped...
1.2.2. Recent Research In March 2014, G. Ivanovs and V. Bobrovs [9] investigated the characteristics of (EDFA) Erbium doped fiber amplifier where
The amplification and fiber depends on different EDFA parameters.A 2.5 Gbit/s one channel WDM transmission system were simulated and measured.
Additionally, simulation of a 4 channel 2.5Gbit/s WDM system was also done containing in–line amplifiers to investigate the EDFA performance for
multichannel system. As they obtained almost identical result of simulated and experimented system it indicated a high accuracy of the simulation.
They investigated that EDFA amplification depends on the signal power, wavelength, EDFA length, and configuration of pump lasers. In June 2014,
Mishal Singla and... Show more content on Helpwriting.net ...
The system analyzed on the basis of received power, BER, gain, noise figure and Q– Factor. The wavelength range was 1528nm to 1562nm at 25dBm
transmission power and 0.5nm channel spacing. The results obtained comparing different pumping techniques to find an appropriate pumping
technique to optimizes the performance of the optical WDM transmission system. Comparative analysis were given in their paper i.e co–pumping,
counter pumping and bidirectional in terms of received power level, BER, gain, noise figure and Q–factor values for pump power varying from 20
mW to 100 Mw. The fiber lengths were varied from 20m to 60. They concluded that the best performance gives bidirectional pumping technique as it
gives simulation. They investigated that EDFA amplification depends on the signal power, wavelength, EDFA length, and configuration of pump
lasers. In June 2014, Mishal Singla and Sanjiv Kumar [10] observed different pumping techniques for 64 channel WDM system for different EDFA
length. In the wavelength range of 1530nm to 1562nm at power–26dBm with 0.5nm spacing, the system was analyzed on the basis of Bit Error Rate
(BER), Received power and Q Factor of three pumping techniques. Comparative analysis were given in their paper i.e co–pumping, counter pumping
and bidirectional in terms of BER(Bit error rate) and Q–factor for different length of

Optical Ofdm For Passive Optical Network
1.Introduction
2.Optical OFDM for Passive optical networks
The high–speed broadband penetration and ongoing growth of the Internet traffic among customers have been the key reasons that are driving the rapid
emergence and deployment of optical access networks as a basic bearer network that supports hybrids services for multiple customers while bearing
huge capacity. Passive optical network is the most interesting solution for the optical access network to cope with the increasing bandwidth demand
and to meet the cost effectiveness. PON can be used for Point to point (P2P) or Point to multi–point (P2MP) configurations. The P2P structure builds a
dedicated fiber from a CO to each subscriber which constitutes an ultimate solution to provide much–needed bandwidth to each ONU. In P2MP
topologies, the feeder fiber is shared between various customers and terminates at a central office in an Optical Line Terminal. Passive splitters put
between the OLT and the ONU are used to split the connection to multiple end points, thus enormously reduces the maintaining cost. Two key
technologies are used in passive optical network: the first one known as TDM–PON uses Time Division Multiplexing to multiplex traffic from/to
multiple ONUs onto the upstream/downstream wavelength. It requires complex scheduling algorithms and framing technology to support a variety of
services. The second is Wavelength division multiplexing passive optical network "WDM PON". This technology comes to extend the

Multiplexing and Data Rate
Multiplexing
CHAPTER 4
Outline * Frequency Division Multiplexing(FDM) * Synchronous Time Division Multiplexing * Statistical Time Division Multiplexing * Asymmetric
Digital Subscriber Line(ADSL)
Multiplexing * Set of techniques that allows the simultaneous transmission of multiple signals across a single link * allows several transmission
sources to share a larger transmission capacity
Link = physical path
Channel = portion of a link that carries a transmission between a given pairs of lines
2 CATEGORY OFMULTIPLEXING
WDM FDM TDM ADSL
Frequency Division Multiplexing
* FDM – numerous signals are combined for transmission on a single communications line or channel. Each signal is ... Show more content on
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TDM : Time Slots and Frames
In a TDM, the data rate of the link is n times faster, and the unit duration is n times shorter.
Time Division Multiplexing
Example 5
Four 1–Kbps

The Simulation Of Data Hiding Using Quad Tree Segmentation
GANNON UNIVERSITY The Simulation Of Data Hiding Using Quad–Tree Segmentation by GANNAVARAM KEERTHI SAGAR This is an
Engineering project submitted to the Gannon University graduate faculty in partial fulfillment for the degree Master of Science in Engineering.
Major Subject: Electrical Engineering Approved: Advising Professor in Charge of Major Work Chairperson of Major Department Gannon
University Erie, Pennsylvania 16541 Dec, 2016 Acknowledgements I take this opportunity to express my profound gratitude and deep regards to
my guide Dr. Niraj Shakhakarmi for his exemplary guidance, monitoring and constant encouragement throughout the course of this project. The help
and guidance given by him time to time shall carry me a long way in the journey of life on which I am about to embark. I also take this opportunity
to express a deep sense of gratitude to Department of Electrical Engineering of the Gannon University for giving me permission to commence this
Project. I am obliged to staff members of Electrical Department, for the valuable information provided by them in their respective fields. I am grateful
for their cooperation during the period of my Project. I would also like to thank my parents for their undeniable support and encouragement which
allowed me to achieve my goals. I also would like to thank my friends who helped me in finishing this project within the limited time. I am making this
project not only for marks but also to

A Literature Survey On Challenges For Efficient High Speed...
A LITERATURE SURVEY ON CHALLENGES FOR EFFICIENT HIGH SPEED COMMUNICATION SYSTEM Pramod Patel1, Amit Mishra2 1.
Dept of ECE, MTECH student, VITS, JABALPUR, M.P., INDIA, 2–Dept of ECE, H.O.D., VITS, JABALPUR, M.P., INDIA, ABSTRACT: The
demands for high bandwidth & high speed application are growing at a faster rate and with the minimum tolerance of error. To enhance available
bandwidth and improve the quality of transmission convolution codes are used on the OFDM (Orthogonal frequency division multiplexing)
communication system over AWGN channel. In OFDM (Orthogonal frequency division multiplexing) systems with channel equalization play a key
role in overcoming distortions caused by phenomena like fading, delay spread and multipath effects. A new framework for designing robust
adaptive filters is introduced. A series of review papers were already available to provide a history of the development of the field until the end of
the last decade. During survey of work we have found that different authors have developed separate methods to solve the purpose. So from the study
of various papers we can easily conclude that there is not any unique method. Hence in this work we come across to develop new adaptive channel
equalization – OFDM algorithm to solve the purpose using MATLAB. KEYWORDS: LMS, NLMS, OFDM, CONVOLUTIONAL CODING, ISI,
Channel estimation. I. INTRODUCTION: These days communication requires a very high rate with high reliability. Two major difficulties that hinder

Progressive Image Transmission Using Ofdm
PROGRESSIVE IMAGE TRANSMISSION USING OFDM Enrol. No. – 13102288 , 13102216 Name of Student– Aman Pandey, Naman Gogia Name
of supervisor(s)–Dr. Abhinav Gupta December – 2016 Submitted in partial fulfillment of the Degree of Bachelor of Technology DEPARTMENT OF
ELECTRONICS AND COMMUNICATION JAYPEE INSTITUTE OF INFORMATION TECHNOLOGY, NOIDA TABLE OF CONTENTS Chapter
No.TopicsPage No. Certificate from the SupervisorII Acknowledgement III SummaryIV List of FiguresV List of Symbols and acronymsVI
Chapter–1Introduction Chapter–2Background 2.1 – OFDM Basics 2.2 – Overview of This OFDM Simulation Project Chapter 3 – Design and
Implementation 3.1 – Overview 3.2 – System Configurations and Parameters 3.3 – Input and Output Description and Results B. Tech (Min 2 Chapters)
Chapter 6 or moreConclusion AppendicesA B C References(IEEE Format) Publications of the Student 1 2 3 Brief Bio–data (Resume) of Student
CERTIFICATE This is to certify that the work titled "Progressive Image Transmission Using OFDM" submitted by "Aman Pandey(13102288) and
Naman Gogia(13102216)" in partial fulfillment for the award of degree of Bachelor of Technology of Jaypee Institute of Information Technology,
Noida has been carried out under my supervision. This work has not been submitted partially or wholly to any other University or Institute for the
award of this or any other degree or diploma. Signature of Supervisor ........................... Name of

Limitations Of Modulation In Isi
Due to the spectacular growth of the wireless services and demands during the last years, the need of a modulation technique that could transmit high
data rates at high bandwidth efficiency strongly imposed. The problem of the inter–symbol interference (ISI) introduced by the frequency selectivity of
the channel became even more imperative once the desired transmission rates dramatically grew up. Using adaptive equalization techniques at the
receiver in order to combat the ISI effects could be the solution, but there are practical difficulties in operating this equalization in real–time conditions
at several Mb/s with compact, low–cost hardware. ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING is a promising candidate that
eliminates the need... Show more content on Helpwriting.net ...
Slow data rate (and long symbol duration) on each subchannel merely means that the effects of ISI are severely reduced. This is in fact the basic
idea that lies behind ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING . Transmitting the data among a large number of closely
spaced subcarriers accounts for the "frequency division multiplexing" part of the name. Unlike the classical frequency division multiplexing
technique, ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING will provide much higher bandwidth efficiency. This is due to the fact
that in ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING the spectra of individual subcarriers are allowed to overlap. In fact, the
carriers are carefully chosen to be orthogonal one another. As it is well known, the orthogonal signals do not interfere, and they can be separated at
the receiver by correlation techniques. The orthogonality of the subcarriers accounts for the first part of the ORTHOGONAL FREQUANCY
DIVISION MULTIPLEXING name. In a mobile radio environment, the signal is carried by a large number of paths with different strength and delays.
Such multipath dispersion of the signal is commonly referred as "channel–induced ISI" and yields the same kind of ISI distortion caused by an
electronic filter [2]. In fact, the multipath dispersion leads to an upper limitation of the transmission rate in order to avoid the frequency selectivity of
the channel or the need of a complex adaptive equalization in the receiver. In

Different Types And Modes Of Mode Selective Devices
LP11 modes (LP11a+LP11b) and even all three modes (LP01+LP11a+LP11b)over few
–mode fiber (FMF)The transmission system with mode
multiplexing are a very crucial problem. The mode selective devices proposed in divided into two major categories: free–space based (FSB) and fiber
based(FB).Free space components are bulky in size ex liquid–crystal–on–silicon (Lcos) spatial light modulator (SLM). But fiber based mode selective
device have compact and easiness of integration. .Firstly proposed 107–Gb/s coherent optical OFDM (CO–OFDM) transmission over a 4.5–km
two–mode fiber using LP01 and LP11 modes. Secondly proposed 58.8–Gb/s CO–OFDM transmission using dual modes where the mode separation is
achieved via 4Г— 4 electronic MIMO processing [10].... Show more content on Helpwriting.net ...
Transfer of energy from one ideal mode to another during propagation only due to mode coupling. It has been observed that practically strong couple
modes having equal or nearly equal propagation constant but weakly coupled modes having a highly unequal propagation constant. The separation
between two modes results in modal dispersion increasing capacity through mode division multiplexing (MDM). SMF ( single–mode fiber helps in the
wave movement in two polarization conditions. Polarization–mode dispersion (PMD) and polarization–dependent loss (PDL) have long been described
by field coupling models. It has been observed that strongly coupled modal group delay or gain depend only no. of modes and variance of
accumulated delay or gain and can be derived from the eigenvalue distributions of certain random variables[12].
SDM (space division multiplexing) has been putforth by Savory. SDM is extremely challenging technology, of requiring developments in all areas of
Photonics Technology. The optical communication systems are being upgraded every day .There is a rapid development taking place in this field at
the global level in the space division multiplexing. Space Division Multiplexing (SDM) is conceptually simple, SDM is extremelychalleng
technologically, requiring the development of new fibers, amplifiers, multiplexers, digital signal processing circuits, and other components. The
multiplexing means the utilization of channel by the division of the space. It is

Advantage And Disadvantage Of Multicarrier Transmission
3.1 Introduction Multicarrier transmission, also known as OFDM is a technique with a long history back to 1960that has recently seen rising
popularity in wireless and wire line. In the recent interest in this technique is mainly due to the recent advances in digital signal processing technology.
The International standards making use of OFDM for high–speed wireless communications are already established or being established by IEEE
802.11, IEEE, 802.16, IEEE 802.20 and ETSIBRAN committees. For wireless applications, an OFDM–based system can be of interest because it
provides greater immunity to multipath fading, and impulse noise, in eliminates the need for equalizers, efficient hardware implementation can be
realized using FFT techniques.... Show more content on Helpwriting.net ...
The OFDM makes single–frequency networks possible, which is especially attractive for broadcasting applications. 3.1.2 Disadvantages of OFDM
Transmission: In the OFDM is more sensitive to frequency offset and phase noise. In OFDM has a relatively large peak–to–average–power ratio,
which tends to reduce the power efficiency of the radio frequency (RF) amplifier. 3.1.3 Application of OFDM During the past decade, OFDM has
been adopted in many wireless communication standards networks, including European digital audio broadcasting system, and terrestrial digital video
broadcasting, and satellite terrestrial interactive multiservice infrastructure in China. In addition, OFDM has been considered or approved by many
groups are working in IEEE standard, such as IEEE 802.11a/g/n standard network, IEEE 802.15.3a, and IEEE 802.16d/e. The applications include
wireless local area networks, wireless personal area networks and wireless metropolitan networks. Currently, OFDMA is being investigated as one of
the most promising radio transmission techniques for LTE of the 3rd Generation Partnership Project (3GPP), International Mobile
Telecommunications–Advanced

Using Orthogonal Frequency Division Multiplexing ( Ofdm )
Abstract multiple carriers are simultaneously modulated using Orthogonal frequency–division multiplexing (OFDM) which is a transmission
technique. Since the OFDM–based system has high spectral efficiency and is robust against intersymbol interference and frequency–selective fading
channels. The major problem of this system is high peak–to–average power ratio (PAPR) of transmitted signal which causes distortion of signal.
At the Receiver, to reduce PAPR in removing weight with no distortion PAPR reducing scheme which is based on a weightedOFDM signal is
proposed. In this scheme, on each discrete OFDM signal through a certain kind of a signal which is band limited a weight is imposed. before a high
power amplifier (HPA), an OFDM signal which is formed with the weighted discrete data is then considered, at the receiver side the original signal can
be collected completely.
Meanwhile, to transmit the weighted OFDM signal the required time duration is same as the original OFDM signal 's time duration. Computer
simulations will evaluate the effectiveness of the scheme which is proposed now. From the numerical results it is observed that , the weighted OFDM
signal has bit error rate (BER) performance that is improved when compared with the C&F method and has PAPR smaller than the clipping and
filtering (C&F) method. Here, the proposed method is simpler than the clipping and Filtering method. Keywords: Bit error rate, Convolution,
Orthogonal Frequency Division Multiplexing

Minimum Mean Square Error Among Ortogonal Frequancy...
The one with the Minimum Mean Square Error (MMSE) among Ortogonal Frequancy Division Multiplexing candidate signals is selected for
transmission. From the results, it can be seen that a proposed scheme based iterative partial transmit sequence can be easily implemented with low
combining complexity, still maintaining a better BER performance and peak to average power ratio reduction, compared to the conventional partial
transmit sequence approach. In mobile communication environment due to fading and multipath, the received signal suffers from random phase
fluctuations. This in turn makes coherent demodulation schemes rather unattractive and impractical. Malode and Patil (2010) proposed the peak to
average power ratio reduction performance... Show more content on Helpwriting.net ...
Chin–Liang Wang and Yuan Ouyang ( 2005) introduce a Selected mapping method .The Selected mapping method approach provides good
performance for peak to average power ratio reduction reduction, but it requires a bank of Inverse Fast Fourier Transforms to generate a set of candidate
transmission signals, and this requirement usually results in high computational complexity. The author suggests low–complexity conversions to
replace the Inverse Fast Fourier Transform blocks in the conventional Selected mapping method method. Two novel Selected mapping method schemes
were proposed with much lower complexity than the conventional one; the first method uses only one Inverse Fast Fourier Transform block to generate
the set of candidate signals, while the second one uses two Inverse Fast Fourier Transform blocks. Computer simulation results show that, as compared
to the conventional Selected mapping method scheme, the first proposed approach has slightly worse peak to average power ratio reduction reduction
performance and the second proposed one reaches almost the same peak to average power ratio reduction reduction performance. Chin Liang wang
continues his investigation by oversampling two times of the Ortogonal Frequancy Division Multiplexing signals by applying peak search and partial
interpolation method. The proposed scheme with two times

Microstrip Antennas : An Analysis
The Microstrip patch antenna has a dielectric substrate with a radiating patch and the feed lines are etched on one side and a ground plane on the other
side. The shape of the patch is not constrained (could be square, rectangular, circular, triangular or elliptical) and it is generally made of conducting
material such as copper or gold. These antennas are mostly used at microwave frequencies, the fringing fields between the patch edge and the ground
plane cause the microstrip patch antennas to radiate. An individual microstrip antenna consists of a patch of metal of various shapes on the surface of a
PCB, with a metal ground plane on the other side of the board. Most microstrip antennas consist of multiple patches in a ... Show more content on
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Further the consideration of space domain either with space diversity, smart antennas, and nowadays, MIMO systems has also pushed the evolution of
propagation modeling toward more complex spatio–temporal considerations [1].The MIMO antenna for wireless communications is required to have a
multiple bandwidth to cover the GSM, and ISM bands. On the other hand, it is said that about 70% of the user demands and mobile flow for
high–speed data services occur in indoor environments [2–3]. In modern antenna design multiple–input multiple–output are employed so that the
multipath effects is taken as advantage to transmit multiple data stream. Designing MIMO antennas have their own challenges such as mutual coupling
because of electromagnetic interaction between antenna elements [4–5].
2.1.2APPLICATIONS OF MICROSTRIPPATCH ANTENNA
Microstrip patch antenna can be used for Mobile and satellite communication, Global
Positioning System, Radio Frequency Identification (RFID), Worldwide Interoperability for Microwave Access (WiMax), Radar, Telemedicine,
Rectenna and Medicinal.Mobile communication requires small, low profile and low–cost antennas. Microstrip patch antennas are meet all
requirements and various types of microstrip antennas have been designed for use in mobile communication systems.In the case of satellite

Channel Partitioning Essay
In data communication, they are always striving to increase throughput, this would include allowing nodes to transmit information over a single
broadcast link without interfering with each other. To achieve this, multiple access protocols coordinate the transmission. There are three classes of
multiple access protocols, random access, taking–turns and channel partitioning. With random access protocol, each node tries to randomly to access
the complete broadcast link, without any regard to the other nodes. Taking–turns protocol utilizes some type of turning mechanism, which designates
which node is allowed to transmit. Channel partitioning protocol divides the channel (time slots, frequency, code) and assigns them evenly between all
of... Show more content on Helpwriting.net ...
There are numerous of taking–turn protocols, two are polling protocol and token–passing protocol. The polling protocol requires one of the node to be
designated as a master node. The master polls each of the nodes in a round–robin fashion. The master first sends a message to node 1, saying that it can
transmit. After node 1 transmits, the master sends a message to node 2 it can transmit The master determines when a node has finished sending its
frames by observing the lack of a signal on the channel. The procedure continues in this manner, with the master polling each of the nodes in a cyclic
manner. (Kurose 459) An advantage of this type of protocol is it avoids collisions, since nodes are only allowed to transmit when they are given access
to the channel. Disadvantage to polling, are delays, as transmitters have to wait for the poll and the centralization with the requirement for a master to
conduct the polling, if it fails the entire channel becomes inoperative. Token–passing protocol there is no master node, instead special–purpose frame
known as a token is exchanged among the nodes in some order. When a node receives a token, it holds onto the token only if it has some frames to
transmit; otherwise, it immediately forwards the token to the next node. If a node does have frames to transmit when it receives the token, it sends up
to a maximum number of frames and then forwards the token to the next node. (Kurose 459) Advantage of token–passing protocol is it

Advantages And Disadvantages Of Mm
One of the major disadvantages of OFDM is the high Peak – to – Average power ratio of OFDM signal. These multi– carrier systems have a problem
that Peak – to – Average power ratio increases with the increase of number of subcarrier, which causes poor efficiency or serious performance
degradation to transmit power amplifier. Many PAPR reduction techniques have been proposed. These techniques can be mainly categorized into signal
scrambling techniques and signal distortion techniques. In this topic, there is study OFDM system and short view of different PAPR reducing techniques
like Clipping, Companding, Peak Windowing, Scrambling, Coding and Selective Mapping (SLM).
Key Words: OFDM, PAPR, SLM, PTS, etc
––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––***–––––––––––––––––––––––––––––––––––––––––––––––––––––
... Show more content on Helpwriting.net ...
Van Nee and Wild suggested peak windowing method. In this method it is possible to remove large peaks. Peak windowing reduces PAPRs as with
respect to increasing the BER and out–of–band radiation. Clipping introduces PAPR reduction technique which is self interference The Peak
windowing offers better PAPR reduction with better properties of spectrum. Peak Windowing technique provides better PAPR reduction with
compare to clipping. [5] In peak windowing, multiplication of large signal peak with a specific window performed, for e.g.; Hamming window,
Kaiser, Gaussian shaped, Cosine, etc.The output spectrum is a convolution of spectrum of the applied window with the original OFDM spectrum.
Hence, the window should have to be as narrow band as possible, in opposition the window not be too long in the time domain because various signal
samples are affected, this resulting increase in bit error rate (BER).[6] 4.1.2 Clipping and Filtering Technique
Figure 2 – Block diagram of Clipping and

Taking a Look at MIMO Techniques
MIMO techniques are mostly used to accelerate system throughput over disruptive wireless communication channels. It is well known fact that with
the number of transmit antenna M and number of receive antenna N, the capacity of MIMO systems increases linearly with a factor of MN. The
receiver decodes the received signal vectors into actual information, a narrow band flat fading MIMO is designed as:
Y=Hx+n –––––– (1)
Where Y & x are received and transmitted vectors, H is channel matrix & n is the noise. During the last decade, MIMO techniques in wireless industry
have gained a huge interest in the study. MIMO is treated as an extension of conventional smart antenna systems (SAS). In SAS, techniques of
beamforming are deployed and the optimal antenna weighting vector that determines antenna radiation pattern is computed based on the optimal
criterion such as maximum signal–to–interference plus noise ratio (SINR), minimum mean square error (MMSE) [8]. The ability to exploit and use the
multipath propagation can be considered as one of the major advantages of MIMO systems. In contrast to transmit beamforming schemes, channel state
information (CSI) is generally not required at the transmitter of MIMO systems. MIMO techniques for transmitting systems can be majorly divided
into two categories: spatial multiplexing and space–time coding (spatial diversity techniques). In spatial multiplexing technique, it increases the data
rate (throughput) over a MIMO dedicated

Matlab Based Design For Resource Allocation Platform
UNDERGRADUATE TETHIS PROJECT PROPOSAL
Zhejiang university of technology
MATLAB BASED DESIGN FOR RESOURCE ALLOCATION PLATFORM
On my honor as a university student, on this assignment I have neither given nor received unauthorized aid as defined by the honor guidelines for
papers in SE course
Name : David kasonga wa kasonga
Supervisor: еђґиїњ
March, 2017
Content
I.Abstract
II.Introduction
III.Research
пѓ Dynamic resource allocation
IV.Objectives
V.Development plan
пѓ Research

пѓ Design
пѓ Simulation & test
VI.Schedule
VII.references
Abstract orthogonal frequency modulation has successfully solved the Inter Symbol Interference problem in frequency selective wireless environment.
An interesting application of ... Show more content on Helpwriting.net ...
In OFDM systems, only a one user can transmit on all of the subcarriers at any given time, and time division multiple access (TDMA) or frequency
division multiple access (FDMA) is used to support multiple users. The major disadvantage of this static multiple access scheme is that the fact that
the different users perform differently in the same given wireless channel is not being taken in consideration. OFDMA, on the other hand, allows
multiple users to transmit simultaneously on the different subcarriers per OFDM symbol at any given time. Since the users perform differently in the
channel probability that all users experience the same fade in a particular subcarrier is very low, though it can be assured that the subcarriers are
assigned to the users who sees good channel gains on them.
While allowing simultaneous access to multiple users to the medium OFDMA has been shown to reduce multi–path fading, within air interfaces in the
IEEE 802.16 standard.
The main advantages of using this multicarrier technology are: higher data rates, longer transmission distance, and better mobility support.
Due to the fact that OFDMA divides the available frequency spectrum into several orthogonal subcarriers, inter–symbol and inter–carrier interference
are minimized, or even eradicated. Also, the assignment of these subcarriers to different users for transmission can be done dynamically, both in
frequency and time dimension. This flexibility provides a way of boosting

Precoding Scheme Essay
ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING techniques allow the transmission of high data rates over broadband radio channels
subject to multipath fading without the need for powerful channel equalization. However it is very sensitive to nonlinear effects due to the high
PEAK TO AVERAGE POWER RATIO owned by their transmitted signals. Slimane Ben Slimane (2007) proposed an efficient technique for reducing
the PEAK TO AVERAGE POWER RATIO of ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING signals. The proposed technique is
data–independent that does not require new processing and optimization for each transmitted ORTHOGONAL FREQUANCY DIVISION
MULTIPLEXING block. The reduction in PEAK TO AVERAGE POWER RATIO of the ORTHOGONAL FREQUANCY DIVISION
... Show more
content on Helpwriting.net ...
The algorithm adaptively selects the appropriate approach to achieve the largest possible decrease in PEAK TO AVERAGE POWER RATIO, given
the available PEAK TO AVERAGE POWER RATIO reduction approaches. In this work, they employed two PEAK TO AVERAGE POWER RATIO
reduction approaches: one is interleaving and the other is subcarrier phase adjustment. The results show that for a wide range of operating conditions,
the proposed algorithm achieves a large decrease in PEAK TO AVERAGE POWER RATIO. A radix FFT
–based technique for reducing the PEAK TO
AVERAGE POWER RATIO of an ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING signal is presented by Ghassemi and Gulliver (2007).
They use intermediate signals in a radix decimation in time or frequency FFT algorithm for sub–block partitioning in the partial transmit sequence
technique. To generate the PTS sequences, multiple transforms are computed within the FFT. Analysis shows that the decimation in time FFT has a
majority of its multiplicative complexity towards the end of the FFT, while the decimation in frequency FFT has a majority towards the beginning.
Thus, decimation in frequency PTS has a much lower multiplicative complexity compared to decimation in time PTS while providing similar PEAK
TO AVERAGE POWER RATIO reduction. A lower multiplicative

Wimax vs. Long Term Evolution
Wimax vs. LTE:
LTE and Wimax are 4G technologies. LTE is Long Term Evolution project which is been proposed by 3GPP (3rd generation partnership project)
which is nothing but collaboration between various telecommunication companies. So LTE has its background from the GSM technology. Wimax is
IEEE 802.16 standard and it's mainly roots in CDMA.
Frequency of operation: LTE operates at lower frequency as compared to wimax. Higher the frequency of operation, higher the attenuation.
Both wimax and LTE uses OFDM (Orthogonal Frequency Division Multiplexing). OFDM uses orthogonal frequencies as carrier frequencies so that
there will be no interference between the signals i.e. it uses the principle of orthogonality. This in turn improves the spectral efficiency.
Multiple Access: Both LTE and wimax uses MIMO (Multiple Input Multiple Output), which a Space Division Multiple Access technique. It is a smart
technique in which the same signal is transmitted in different streams to the receiver. The receiver choses the best of the transmitted signal streams and
decodes the signal. It is chosen such a way that, the best quality signal is obtained. So, even the weaker signals are boosted up by this technique.
Infrastructure: Both LTE and wimax uses ip infrastructure. The flat structure of ip helps the mobile as well as the base station.
Latency: Latency is less in LTE when compared to wimax.
Range: Theoretically LTE has better rang than wimax.
Speed: speed of LTE is way higher than

Design And Fpga Implementation Of Ofdm Synchronization
Chapter 5 Design and FPGA Implementation of
OFDM Synchronization The channel estimation technique proposed in Chapter 4 is based on the assumption that the coherent reception is perfect.
That is, the system synchronization is perfectly implemented. Synchronization is one of the most challenging and important tasks to any receiver using
coherent modulation, especially for OFDM systems which are highly sensitive to synchronization errors. This chapter proposes a synchronizer based
upon the delay and correlation algorithm and the synchronization system is modeled within XSG.
Simulation results have been provided for presenting the system synchronization performance clearly. The implementation results on FPGA are given
at the end. 5.1 Synchronization for OFDM
5.1.1 Introduction to OFDM Synchronization
Generally speaking, synchronization is divided into timing and frequency synchronization. In practice, the oscillator does not produce a carrier at
exactly one frequency, and the carrier frequency is modulated by random phase jitter [2]. The phase noise introduced results in a mismatch of
frequencies between the local oscillators at the transmitter and the receiver. In addition, Doppler effects infading channel also causes frequency offsets
at the receiving carrier. As a result, the numbers of subcarriers cycles within the FFT period are not integers anymore, and the orthogonality property
between subcarriers is not kept, causing ICI for an OFDM system. In contrast, in a

The Performance Of Space Time Block Codes ( Stbc )
пїјPerformance of Space Time Block Codes(STBC)
Anuj Mehta
School of Electrical Engineering & Telecommunication, UNSW
Sydney, Australia
Z3488506@zmail.unsw.edu.au
Abstract– In the following paper we are going to discuss the different coding techniques such as Orthogonal STBC , Alamouti's coding and their
performance on a QPSK signal with Rayleigh fading. We will plot it for SNR values ranging from 0dB to 40 dB. In this we will be taking different
combination for number of transmitting and the radiating antenna used.
Keywords–Alamouti's,OSTBC,SNR
I. INTRODUCTION
In the field of telecommunications wireless communication is the most advanced and widely used method for long distance communication. Wireless
Communication today faces various ... Show more content on Helpwriting.net ...
Number of reception (independent) by the MIMO system is called diversity gain. The Diversity Gain, which is also known as Diversity Order is
given by . Where пїј is number of receiving antenna and is number of Transmitting antenna.
II. SYSTEM AND SIGNAL MODEL
Shrey Yadav
School of Electrical Engineering & Telecommunication, UNSW
Sydney, Australia
Z5024542@zmail.unsw.edu.au
A. ALAMOUTI'S CODING (M=N=2)
Alamouti's coding includes 2 transmitting and 2 receiving antennas. The h matrix for this type would be 2x2 matrix. The transmission rate is also
optimized to the full capacity as it transmits 2 signals in 2 time slots. The full data rate can be achieved in this coding technique.
FIGURE 1. A 2X2 MIMO WIRELESS SYSTEM USING THE ALAMOUTI'S BLOCK CODE
For 1st time slot
For 2nd time slot
Combined equation:
пїјпїјпїјпїјпїјпїј

пїјB. OSTBC (M=4,N=1)
This sort of code is otherwise called 4–recieving wire alamouti 's code. Tarokh et al. found a set of STBC's that are especially clear, and termed the
plan 's name as Orthogonal STBC. They likewise demonstrated that it was impractical to accomplish full rate code, if there were more than 2 transmit
antennas utilized as a part of the correspondence.
FIGURE 2. A 4X1 MIMO WIRELESS SYSTEM USING THE ORTHOGONAL STBC
System equations:
III. MAIN RESULTS
By performing this examination, we have learnt that coding enhances the general execution of the MIMO. It can be seen that without coding,

Ordered Successive Interference Cancellation ( Osic ) Is...
Abstract– In this paper, ordered successive interference cancellation (OSIC) is adopted with minimum mean square error (MMSE) detection to enhance
the multiple–input multiple–output (MIMO) system performance. The optimum detection technique increases the system complexity with improved
error rate performance. Therefore, MMSE–OSIC detection is used which gives reduced error rate compared to traditional MMSE with a considerable
level of complexity. The system performance is analyzed in a compositefading environment which deals with multipath and shadowing, known as
Weibull–gamma (WG) fading environment. Along with the composite fading, a composite noise i.e. additive white generalized Gaussian noise
(AWGGN) model is taken into account to form various noise scenarios such as impulsive, Gamma, Laplacian, Gaussian and uniform noise.
Consequently, generalized Q– function is used to develop such noise scenario. The average symbol error probability (ASEP) of MIMO system is
computed for 16–quadrature amplitude modulation (16–QAM) using MMSE–OSIC detection in WG fading with AWGGN. Analytical expressions are
evaluated in terms of Fox–H function (FHF). These expressions demonstrate the best fit to simulation results.
Keywords– MIMO, MMSE–OSIC, WG fading, AWGGN, M–QAM, ASEP.
1.Introduction
In MIMO systems, spatial multiplexing is used for high data rate transmission and spatial diversity is used to achieve reliable communication.
However, there is a tradeoff between diversity and

The Technique Of Energy Harvesting From Radio Signals
1.Introduction:
The technique of energy harvesting from radio signals has received much attention in various applications in the recent time, such as radio–frequency
identification systems [1] and body sensor networks with medical implants [2]. According to the 2010 wireless smart phone customer satisfaction
study from J. D. Power and Associates, the iPhone received top marks in every category except for battery life. The latest report in China also reflects
the same problem. Based on the data, up to 60% of the users complained that battery endurance was the greatest hurdle when using 3G services.
(Daquan Feng, 2013) In recent year, a new concept of energy harvesting from wireless signal is the subject of interest of many researchers and ... Show
more content on Helpwriting.net ...
We are using orthogonal frequency divisionmultiplexing (OFDM) modulation technique for Energy harvesting and information transfer. OFDM is
most efficient and noise resistant scheme of modulation in wireless communication technology. Orthogonal frequency–division multiplexing (OFDM)
is a method of digital modulation in which a signal is split into several narrowband channels at different frequencies. OFDM is used in applications
such as digital television and audio broadcasting, DSL Internet access, wireless networks, 3G and 4G mobile communications. (Yair, 2006)
This report would throw light on the different methodology approached for the wireless energy harvesting for project. Further, it would emphasize the
work done during the first semester on the project. Moreover, it would highlight the line of action to be taken in order to complete the project in the
next semester.
2.Literature Review:
Wireless energy harvesting is an emerging topic of interest for communication and signal processing researchers. Varshney first proposed the idea of
transmitting information and energy simultaneously in [2] assuming that the receiver is able to decode information and harvest energy simultaneously
from the same received signal. For the proposed receiver, in [4] the authors used a capacity–energy function to study the fundamental performance
tradeoff for

Advantages And Disadvantages Of Multicarrier Modulation
Multicarrier modulation is a technique of transmitting data over several subchannels instead of transmitting the data over the whole bandwidth in
single carrier systems. The data stream to be transmitted is divided into a number of lower data rate data streams. The subchannels have narrow
bandwidth compared to wideband channel in single carrier systems and also the symbol period on each subchannel is increased.
Multicarrier modulation provides immunity to fading caused by data transmission over mul–tipath fading channels or frequency– selective fading
channels. Each of the subchannel expe–riences flat fading due to the decreased bandwidth. Also, due to the increase in the symbol period, it provides
enhanced immunity to ISI. Another advantage of multicarrier modulation technique is it can provide better spectral efficiency compared to single
carrier modulation, since the spectrum of the subcarrier can be overlapped.
Although there are advantages, multicarrier modulation technique has disadvantages such as requirement of synchronization with marginal conditions
, higher Peak–to–Average Power Ra–tio (PAPR) implying strict requirement for amplifier to be linear.
A number of multicarrier modulation technique has involved. Few of them are OFDM, ... Show more content on Helpwriting.net ...
These sub–carriers are orthogonal to each other. It is very much popular scheme used in digital television, audio broadcasting and 4G communications.
OFDM has the ability to deal with severe channel fading conditions without complex equalization filters. Due to the longer symbol period and the CP
extension, OFDM is more robust against the effect of timing offset and delay spread in multipath fading channels. OFDM also gain higher spectral
efficiency due to the overlapping of the subcarrier spectrum which are orthogonal to each other. The major drawback of OFDM is high

Advantages And Modes Of Effective Devices
modes to generate LP11 modes (LP11a+LP11b) and even all three modes (LP01+LP11a+LP11b)over few–mode fiber (FMF)The transmission system
with mode multiplexing are a very crucial problem. The mode selective devices proposed in divided into two major categories: free–space based
(FSB) and fiber based(FB).Free space components are bulky in size ex liquid–crystal–on–silicon (LCOS) spatial light modulator (SLM). But fiber
based mode selective device have compact and easiness of integration. .Firstly proposed 107–Gb/s coherent optical OFDM (CO–OFDM) transmission
over a 4.5–km two–mode fiber using LP01 and LP11 modes. Secondly proposed 58.8–Gb/s CO–OFDM transmission using dual modes where the
mode separation is achieved via 4Г— 4 electronic MIMO... Show more content on Helpwriting.net ...
Transfer of energy from one ideal mode to another during propagation only due to mode coupling. It has been observed that practically strong couple
modes having equal or nearly equal propagation constant but weakly coupled modes having a highly unequal propagation constant. The separation
between two modes results in modal dispersion increasing capacity through mode division multiplexing (MDM). SMF ( single–mode fiber helps in the
wave movement in two polarization conditions. Polarization–mode dispersion (PMD) and polarization–dependent loss (PDL) have long been described
by field coupling models. It has been observed that strongly coupled modal group delay or gain depend only no. of modes and variance of
accumulated delay or gain and can be derived from the eigenvalue distributions of certain random variables[7].
SDM (space division multiplexing) has been putforth by Savory. SDM is extremely challenging technology, of requiring developments in all areas of
Photonics Technology. The optical communication systems are being upgraded every day .There is a rapid development taking place in this field at
the global level in the space division multiplexing. Space Division Multiplexing (SDM) is conceptually simple, SDM is extremely challeng
technologically, requiring the development of new fibers, amplifiers, multiplexers, digital signal processing circuits, and other components. The
multiplexing means the utilization of channel by the

Different Indoor Broadcasting Schemes Based On Plc And Vlc
4. DESIGN METHODOLOGY
Fig. 5. Block diagram of "PLC to VLC" module.
Fig. 6. System models of the different indoor broadcasting schemes based on PLC and VLC. (a) Classical VLC–based broadcasting scheme (Scheme
A). (b) Classical PLC and VLC–based broadcasting scheme (Scheme B). (c) Proposed deeply integrated PLC and VLC system for indoor broadcasting.
5. RESULTS Figure 7. Demonstration setup of the broadcasting system in the laboratorial environment. Fgure 8. Block diagram of the laboratorial
demonstration.
6. Performance Evaluation
The high–definition TV program is modulated by the time domain OFDM (TDS–OFDM), and then transmitted in the hybrid system to evaluate its
performance. We use the mode (64QAM, Multi–carrier, PN420, FEC 0.6, TI 720) [30] for the first–step demo. The system bandwidth is 8 MHz located
from 2 MHz to 10 MHz. The point to point system (with one LED lamp on) can still work well with the visible light path
Fig. 9. PLC modulator.
Fig. 10. Demodulator in the receiver.
up to 8 meters with the interference from the normal indoor lighting devices and provide a date rate of around 48 Mbps within 8MHz bandwidth.
For the two LED lamps, LED A is connected directly to the PLC modulator and LED B is connected to the modulator via a section of power line.
Since 3 m is the typical height of the ceilings in many indoor scenarios, the receiver which contains the APD is placed with an equal distance of 3
meters away from the two LED lamps to

Error Performance Improvement Of A Multiplexed Mimo...
Error Performance improvement in Spatially Multiplexed MIMO Systems over Weibull–Gamma Fading Channel
Keerti Tiwari and Davinder S. Saini
Department of Electronics and Communication Engineering
Jaypee University of Information Technology
Waknaghat, Solan, (H.P.)– 173234, India
E–mail– keerti.tiwari@mail.juit.ac.in, davinder.saini@juit.ac.in
Abstract– In multiple–input multiple–output (MIMO) systems, spatial demultiplexing at the receiver is a motivational task. Thus, several detection
techniques are investigated in existing literature. There is a tradeoff between computational complexity and optimal performance in many detection
techniques. The ordered successive interference cancellation (OSIC) with minimum mean square error (MMSE) is used to improve the error
performance. However, maximum likelihood (ML) detection gives optimal performance at the higher complexity level whereas MMSE–OSIC
detection is less complex. Therefore, MMSE–OSIC2 detection is suggested as a solution. In this paper, spatial multiplexed (SM) MIMO systems are
considered to evaluate error performance with different detection techniques such as MMSE–OSIC, ML and MMSE–OSIC2 in a composite fading i.e.
Weibull–gamma (WG) fading environment. In WG distribution, Weibull and gamma distribution represent multipath and shadowing effects
respectively. It is shown by simulation results that the MMSE–OSIC2 detection technique gives the improved symbol error performance (SER) which
is closely likely ML performance

The Importance Of Optical Communication
Design of Non optical Carrier Single Sideband and wavelength reused DWDM passive optical network with Wired/Wireless Services Incorporating
OFDM
Abstract– In this work, an integrated passive optical network and free space optical communication system based on no–carrier single sideband
modulation is proposed. Optical orthogonal frequency multiplexing is employed with dense wavelength division multiplexing to support 16 channels
over 300 km bidirectional single mode fiber to enhance spectral efficiency and reduce inter–symbol interference. Moreover, wavelength reuse is also
realized to design cost effective optical network units. Results revealed that the proposed framework successfully accomplished the 300 km
symmetrical distance and ... Show more content on Helpwriting.net ...
Literature of OFDM system provides us that there are significantly three kinds of the OFDM such as direct detection, coherent detection and
heterodyne detection. However, all the aforementioned types can be used in the systems based on the specifications or user demands [7]. To
understand the cost effective system, direct detection and heterodyne reception are ideal beneficiaries [8]. In any case, regardless the utilization of
single photo–detector in reception of OFDM signals and offers the cost effective modulation, it experiences short separation transmissions [9]. Due to
phase matching at the receiver, CO–OFDM is considered as the unmistakable and potential contender for long separation transmissions [10]. Till now,
different methodologies are exhibited to create a dependable OFDM signals incorporating double side band and single side band modulation [11].
Disadvantage in the former modulation such as double side band (DSB) modulation, is the bandwidth inefficiency and limiting effects of power
fading because of dispersion effects [12]. Unexpectedly, single sideband balance offers more noteworthy insusceptibility or resistance to scattering
impacts and procures less data transmission in the optical fiber [13]. Also, it is studied that the optical carrier to signal power ratio (CSPR) is vital
parameter in the frameworks that utilized the single side band adjustment in OFDM. Nonlinearities are because of high power, in the fiber,

Design And Implementation Of Mimo Ofdm
CAREER EPISODE –1Mohd Saem (a)Introduction CE 1.1 CHRONOLOGY Project Title Design and Implementation of MIMO OFDM Dates for the
Project 2012 – 2013 Duration 1 year Name of the Organization Electronics and Telecommunication Engineering Department Location New Rizvi
Educational Complex, Off Carter Road, Bandra West, Mumbai, Maharashtra 400050, India My Role Project Demonstrator and project lead (b)
Background CE 1.2Rizvi college of engineering is a part of the Rizvi Education Society, which is a public charitable trust. It was Established in the
year 1950 under the Societies act and was listed under the requirements of Bombay Public act. This Society promotes various fields of education like
Hospitality, Hotel management, Science, Commerce, Arts, Fashion Designing and Engineering. The location of college is ideal enviroments for
students to achieve their goals in life. CE 1.3 The main objective of this project was to successfully implement transceiver that would help in
developing 802.11 n modem. The architecture required the realization of 802.16 (Wi–max) and LTE transceivers. It intended to study various
alternatives for implementation of the OFDM which resulted in reduced chip size. It included developing a complete system of indigenously developed
802.11n modem which then offered maximum throughput, robust and highly scalable WLAN connections/networks. CE 1.4 The principal role and

Advantages And Disadvantages Of 5.1 Ofdm-IDMA Scheme
5.1 OFDM–IDMA Scheme
Various multiple access technique like TDMA, CDMA, FDMA has been used in wireless network for communication. But OFDM i.e orthogonal
frequency division multiple access offers number of advantages over these multiple access techniques, such as this scheme can provide simple
treatment against ISI and also reduces cross cell interference. The IDMA in combination with OFDM allow effective and simple turbo type iterative
MUD algorithm which can be easily implemented to large number of users, which help to obtaining high throughout. MUD (multiple user detection)
also provides potential solution to MAI (multiple access technique) problem. IDMA also allow low cost chip by chip (CBC) MUD detection
algorithum, but the complexity increases linearly with ... Show more content on Helpwriting.net ...
But then also there are some disadvantages related to OFDM–CDMA systems. To differentiate among different users OFDM–CDMA uses different
orthogonal codes and due to this orthogonality distortion occurs among users in frequency selective channel (especially in uplink transmission), which
may cause problem of MAI. For MAI problem, MUD is a promising technique which is very complex in practical application. The detectors for
OFDM–IDMA system like the linear MMSE detector and other de–correlator have the quadratic complexity with the number of users say K [22]. This
quadratic complexity occurs to resolving the correlation operations involved in spreading sequences. The computational prohibitive occur for practical
implementation if value of K is large.
For coding in OFDM–CDMA systems using spreading sequences for separation of users is not good, because the spreading operation results in
expansion of band– width with no coding gain. In [23] theoretical analysis has been made which shows that the capacity of multiple access channel
can be reached if the entire bandwidth expansion is due to the use of FEC

Rake Receiver Method Of Multipath Fading Reduction
RAKE RECEIVER METHOD OF MULTIPATH FADING REDUCTION
S.D Dayo1, K.O Egbo2,
1Department of Electrical and Electronics Engineering Ladoke Akintola University of Technology, Ogbomosho.
2 Department of Physics, Federal University of Technology, Owerri, Imo State
ABSTRACT
Wireless communications is, by any measure, the fastest growing segment of the communications industry. It has captured the attention of the media
and the imagination of the public. However, the fundamental phenomenon which makes transmission unreliable is time varying fading. The
phenomenon is described as the constructive/destructive interference between signals arriving at the same antenna via different paths, and hence with
different delays and phases, resulting in random fluctuations of the signal level at the receiver. This paper investigates Rake receiver method of
combating fading.
The rake receiver uses a combination of correlators to separately detect M strongest multipath components, code generators, and delays, or "fingers",
to spread out the individual echo signals of the multipath. Each signal is then delayed according to peaks found in the received signal. The rake
receiver uses several "sub–receivers" each delayed slightly in order to tune in to the individual multipath components. Each component is decoded
independently, but at a later stage combined using delay compensate combiner and MRC dispreading in order to make the most use of the different
transmission characteristics of each

The Evolution Of Optical Networks
Optical network is designed to transmit digital signals in the form of pulses of light. Optical fiber is used as medium for transmission. Optical
fiber is a thin, flexible, transparent fiber (glass or plastic) that acts as a waveguide to transmit light between the ends of the fiber. Optical fiber
consists of a central glass core surrounded by a cladding layer whose refractive index is slightly lower than the core index. Such fibers are generally
referred to as step index fiber to distinguish them from graded index fiber in which the refractive index of the core decreases gradually from center to
core boundary. Working principle for transmission is total internal reflection (TIR). Figure 1.1 Light propagation in fiber
Optical ... Show more content on Helpwriting.net ...
In such kinds of optical networks, both the traffic passing by and ending at a node is converted from the optical domain to the electrical domain and
switched electronically to an output port (including a port that can drop traffic locally). Following electronic switching, the traffic passing by a node is
converted back to the optical domain before departing from the node. With the increase in data transmission rate, electrical switching and
optical–electrical–optical (OEO) conversion result in a significant growth in complexity and cost for electronic devices. Therefore, reducing the
burden placed on the underlying electronic devices in a node and removing electronic switching for traffic passing by a node became key factors in the
development of second generation optical networks. The switching and processing of bits were, however, handled in the electronic domain as before.
1.2.2 Second Generation Optical Networks
These networks were made capable of using multiple carrier wavelengths that were multiplexed onto a single fiber thus offering increased bandwidth.
The technique is called wavelength division multiplexing. From technological point of view, incorporating the switching and routing functionality in the
optical domain and allowing for the transparency of data format, protocol and bit rates are the achievements of second generation over

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