Advantages And Disadvantages Of 5.1 Ofdm-IDMA Scheme

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
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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
... Get more on HelpWriting.net ...

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 4× 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

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

Design And Implementation Of Mimo Ofdm
CAREER EPISODE –1 Mohd 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 1.2 Rizvi 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

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

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

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: 吴远
March, 2017
Content
I. Abstract
II. Introduction
III. Research
 Dynamic resource allocation
IV. Objectives
V. Development plan
 Research
 Design
 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
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

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 division multiplexing (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

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

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
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

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 μs. 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 same time. 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–λ (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 µs propagation delay
Transmission Time = (100 bps/10,000,000 bps) = 10 µs
Slot Time = 10µ seconds + 50 µ seconds = 60 µs
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

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

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

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 in fading 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 )
Performance 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
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 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:

B. 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,

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

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 weighted OFDM 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

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 OF MULTIPLEXING
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 Helpwriting.net ...
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

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

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
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

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 Helpwriting.net ...
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].
2.1.2 APPLICATIONS OF MICROSTRIP PATCH 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

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

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

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

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

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
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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

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

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 composite fading 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

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
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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 the T–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

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

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,

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
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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 4× 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
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

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

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
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

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. Topics Page No.
Certificate from the Supervisor II Acknowledgement III Summary IV List of Figures V List of
Symbols and acronyms VI Chapter–1 Introduction Chapter–2 Background 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 more Conclusion Appendices A 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

Applying A New Localization Approach Based On...
A 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

Advantages And Disadvantages Of 5.1 Ofdm-IDMA Scheme

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