Electronics and Computer Engineering Master Program

Advanced Wireless Communications (8701611)

Second Semester 2012/2013

Assignment: Computer Simulation of OFDM System

It is required to simulate the performance of OFDM system in Additive White Gaussian Noise (AWGN) channel. Particularly, each student should investigate the effect of various parameters such as SNR, cyclic prefix/guard interval, number of subcarriers M, number of Monte-Carlo simulation loop nloop, type of modulation (qammod, pskmod) with different values of modulation levels q. Given the Matlab code that implements the OFDM system in AWGN channel, it is required to prepare a report that includes the following: 1. Study the effect of the length of the guard interval on the BER performance of the system. Provide one Matlab figure (Fig. 1) showing the BER vs SNR performance when the length of the guard interval is M/2, M/4, M/8, M/16, M=1024, nloop=100000, q=4. Comment on the results. 2. Study the effect of number of subcarriers on the BER performance of the system. Provide one Matlab figure (Fig. 2) showing the BER vs SNR performance when the guard interval is M/4, nloop=100000, q=4, and for different number of subcarriers: M=256, M=512, M=1024, M=2048. Comment on the results. 3. Study the effect of the length of the Monte-Carlo simulation loop on the BER performance of the system. Provide one Matlab figure (Fig. 3) showing the BER vs SNR performance when the guard interval is M/4, M=1024, q=4, and for different values of the loop: nloop=10, nloop=1000, nloop=100000, nloop=10000000. Comment on the results. 4. Study the effect of the Quadrature Amplitude Modulation (QAM) with different modulation levels on the BER performance of the system. Provide one Matlab figure (Fig. 4) showing the BER vs SNR performance when the guard interval is M/4, M=1024, nloop=100000, and for different values of modulation levels: “q=4 QAM”,...

...Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.401-409
Twisted Amplitude PhaseShiftKeying
ABSTRACT
Several modulation techniques are defined in digital modulation, Here we are discussing about in four modulation techniques,8-PSK,8-TAPSK,16TAPSK and 16-QAM. In the paper we derive minimum non coherent distance(dnc)of block coded TAPSK and compare it with different modulation techniques, i.e. 8-PSK and 16-QAM using linear component codes. If the block length N is very small.NBC-16-TAPSK performs best among all non-coherent scheme and NBC-16QAM perform wrose due to its small minimum noncoherent distance. However, if the block length N is not short, NBC-16QAM has the best error performance because the code words with small non-coherent distances are rare. GENERAL TERMS-Non-coherent detection, block coded modulation(BCM), multilevel coding(MLC), bit error rate(BER), Signal to noise ratio(SNR). KEYWORDS-AWGN, Rayleigh, Flat fading channel related to SNR, that is high BER causes low SNR. High BER causes increases packet loss, increase in delay and decreases throughputin wireless channels, several models have been proposed and investigated to calculate SNR. All the models are a function of the distance between the sender and the receiver, the path loss exponent and the channel gain.The AWGN channel which introduces an unknown carrier phase rotation has been investigated in many...

...Aim : To design an optical data communication network which uses Offset Quadrature PhaseShiftKeying modulation technique.
oftSware used : Optisystem
Components used:
1) Psuedo Random Bit Sequence Generator
2) RZ Pulse Generator
3) Fork 1x2
4) Oscilloscope Visualiser
5) RF Spectrum Analyser
6) OQPSK Modulator
7) Quadrature De-modulator
8) M-ary Threshold Detector
9) Eye Diagram Analyzer
10) PSK Sequence Decoder
Components Description and their Specifications:
PRBS Generator :
In this project, the data is in the form of digital data i.e 0’s & 1’s. Hence in order to generate a digital sequence we do need a data generating source, hence we use a digital data source generating a random binary sequence known as pseudo random binary sequence generator. The bit sequence is designed to approximate the characteristics of random data.
Bit rate = 30375000 bits/sec
Order = 8
RZ Pulse Generator : Generates a Return to Zero (RZ) coded signal. It uses RZ line coding technique to generate electrical signal using binary pulses as it’s input.
Duty cycle is 0.5 bits. Rise time and Fall time both are equal to 0.05 bits.
Sample rate = 1.94 GHz
Fork 1x2 : Here in this project , the bit sequence is to be given to RZ pulse generator and OQPSK modulator. Fork 1x2 copies the input signal into two...

... Today’s National Guard
26 February 2012
In early colonial times, a need for protection and security for the town and families was sought. The National Guards roots date back to 1636 when colonial Militia, made up of ordinary citizen, would put down their plows and pick up their weapons to protect families and towns from hostile attack (National Guard, 2012). This is where the term citizen solider comes from. Every day people either it be store owners, inn keepers, or a local farmer in the field, would be ready to pick up their weapons at a moment’s notice would defend and protect their community. Even in the earliest beginnings of this nation, the National Guard helped in development of it community whenever possible. This dedication and personal sacrifice has been the driving force in the citizen solider since the beginning. Serving the community has been the goal of the National Guard. Providing relief efforts both in the...

...
THE GUARD
For a brief moment, while waiting for my instructor to check the plotter, I glanced out through the window of the gunnery storeroom at the surrounding Ambala countryside. It lay green and crisp beneath a crackling December sun. Winter was already tightening its cold embrace over North India.
Behind me lay the boundary fence of the command Air Force base, the largest air force station north of Delhi. And beyond the Air Force station was the Grand Trunk Road, the life line connecting Srinagar with New Delhi. The constant shrieking take offs & touch downs of fighter planes certainly disturbed the cantonment ambience and was an ever present source of irritation for us. It is better to have well trained fighter pilots I thought, than have semi skilled ones who may drop missiles at our own advancing troops in the frenzy of a war!
Ahead of me was the parade ground of our regiment – First Field Regiment, flanked by twin rows of Asoka trees, which were now gently swaying in the breeze. Beyond the ground were the barracks – the living quarters of Jawans, behind which were the M T vehicle park. To my left were the regimental office buildings, all single story lines of rooms with a quarter guard and its regimental flag, Sentry & Kote where the regimental weapons were safely kept. Far away to my right stood the air field tower like a Qutab Minar under the winter sun.
I had just joined the oldest Artillery Regiment of Indian Army soon...

...modulation of a 1MHz sine wave. A phasor diagram shows the impact of poor synchronization with the local oscillator. Digital processing is used to remove phase and frequency errors. Since the early days of electronics, as advances in technology were taking place, the boundaries of both local and global communication began eroding, resulting in a world that is smaller and hence more easily accessible for the sharing of knowledge and information. The pioneering work by Bell and Marconi formed the cornerstone of the information age that exists today and paved the way for the future of telecommunications. Traditionally, local communication was done over wires, as this presented a cost-effective way of ensuring a reliable transfer of information. However, for long-distance communications, transmission of information over radio waves was needed. Although this was convenient from a hardware standpoint, radio-waves transmission raised doubts about the corruption of the information; transmission was often dependent on high-power transmitters to overcome weather conditions, large buildings, and interference from other sources of electromagnetics. The various modulation techniques offered different solutions in terms of cost-effectiveness and quality of received signals but until recently were still largely analog. Frequency modulation and phase modulation presented a certain immunity to noise, whereas amplitude modulation was simpler to demodulate....

...and one much more specific.[7] In the generic sense the term post bureaucratic is often used to describe a range of ideas developed since the 1980s that specifically contrast themselves with Weber's ideal type bureaucracy. This may include total quality management, culture management and matrix management, amongst others. None of these however has left behind the core tenets of Bureaucracy. Hierarchies still exist, authority is still Weber's rational, legal type, and the organization is still rule bound. Heckscher, arguing along these lines, describes them as cleaned up bureaucracies,[8] rather than a fundamental shift away from bureaucracy. Gideon Kunda, in his classic study of culture management at 'Tech' argued that 'the essence of bureaucratic control - the formalisation, codification and enforcement of rules and regulations - does not change in principle.....it shifts focus from organizational structure to the organization's culture'.
Another smaller group of theorists have developed the theory of the Post-Bureaucratic Organization.,[8] provide a detailed discussion which attempts to describe an organization that is fundamentally not bureaucratic. Charles Heckscher has developed an ideal type, the post-bureaucratic organization, in which decisions are based on dialogue and consensus rather than authority and command, the organization is a network rather than a hierarchy, open at the boundaries (in direct contrast to culture management);...

...pounds. a. What is the estimated population mean? b. Determine a 95 percent confidence interval for the population mean.
a) The estimated population mean = 3.01 pounds
b) Here it is given that, xbar = 3.01, s = 0.03, n = 36.
The Standard error of the mean, SE = s/Sqrt(n) = 0.03/Sqrt(36) = 0.005
The z- score for 95% confidence is z = 1.96
A 95 percent confidence interval for the population mean is given by
(xbar – z*SE, xbar + z*SE)
= (3.01 – 1.96*0.005, 3.01 + 1.96*0.005)
= (3.01 – 0.0098, 3.01 +0.0098)
= (3.0002, 3.0198)
Confidence Interval using Student’s t distribution
Here, t = 2.0301 for 95% confidence with 34 d.f.
A 95 percent confidence interval for the population mean is given by
(xbar – t*SE, xbar + t*SE)
= (3.01 – 2.0301 *0.005, 3.01 + 2.0301 *0.005)
= (3.01 – 0.0102, 3.01 +0.0102)
= (2.9998, 3.0202)
Exercise 34. A recent survey of 50 executives who were laid off from their previous position revealed it took a mean of 26 weeks for them to find another position. The standard deviation of the sample was 6.2 weeks. Construct a 95 percent confidence interval for the population mean. Is it reasonable that the population mean is 28 weeks? Justify your answer.
Here it is given that, xbar = 26, s = 6.2, n = 50.
The Standard error of the mean, SE = s/Sqrt(n) = 6.2/Sqrt(50) = 0.8768
The z- score for 95% confidence is z = 1.96
A 95 percent confidence...

...95% confidence interval for the proportion of adult males 20 to 34 who have
hypertension. Interpret the confidence interval.
You wish to conduct your own study to determine the proportion of adult males 20 to 34 years
old who have hypertension.
(c) What sample size would be needed for the estimate to be within 3 percentage points (interval
length is 0.06) with 95% confidence if you use the point estimate obtained in part (a)?
(d) What sample size would be needed for the estimate to be within 3 percentage points with 95%
confidence if you don’t have a prior estimate (use phat=.5)?
4. A random sample of 60 married couples who have been married 7 years was asked the number of
children they have. The results of the survey are as follows:
0
0
0
3
3
3
1
3
2
2
3
1
3
2
4
0
3
3
3
1
0
2
3
3
1
4
2
3
1
3
3
5
0
2
3
0
4
4
2
2
3
2
2
2
2
3
4
3
2
2
1
4
3
2
4
2
1
2
3
2
The data is also in Excel format on Blackboard: FamilySizeData.xls.
(a) Obtain a point estimate for the mean and standard deviation number of children of all couples
who have been married 7 years.
(b) What is the shape of the distribution of the sample mean? Why?
(c) Compute a 95% confidence interval for the mean number of children of all couples who have
been married 7 years. Interpret this...