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OFDM Transmitter, Reciever Matlab Codes – OFDM Modem In Matlab

March 16th, 2009 No comments

Abstract

Orthogonal frequency division multiplexing (OFDM) is becoming the chosen
modulation technique for wireless communications. OFDM can provide large data
rates with sufficient robustness to radio channel impairments. Many research centers
in the world have specialized teams working in the optimization of OFDM for
countless applications.
The purpose of this report is to provide Matlab code to simulate the basic processing
involved in the generation and reception of an OFDM signal in a physical
channel and to provide a description of each of the steps involved.

Introduction

In an OFDM scheme, a large number of orthogonal, overlapping, narrow band
sub-channels or subcarriers, transmitted in parallel, divide the available transmission
bandwidth. The separation of the subcarriers is theoretically minimal such that
there is a very compact spectral utilization. The attraction of OFDM is mainly due to
how the system handles the multipath interference at the receiver. Multipath generates
two effects: frequency selective fading and intersymbol interference (ISI).
The “flatness” perceived by a narrow-band channel overcomes the former, and
modulating at a very low symbol rate, which makes the symbols much longer than
the channel impulse response, diminishes the latter. Using powerful error correcting
codes together with time and frequency interleaving yields even more robustness
against frequency selective fading, and the insertion of an extra guard interval
between consecutive OFDM symbols can reduce the effects of ISI even more.
Thus, an equalizer in the receiver is not necessary.
There are two main drawbacks with OFDM, the large dynamic range of the
signal (also referred as peak-to average [PAR] ratio) and its sensitivity to frequency
errors. These in turn are the main research topics of OFDM in many research centers
around the world, including the SARL.
A block diagram of the European DVB-T standard is shown in Figure 1.1. Most
of the processes described in this diagram are performed within a digital signal
processor (DSP), but the aforementioned drawbacks occur in the physical channel;
i.e., the output signal of this system. Therefore, it is the purpose of this project to
provide a description of each of the steps involved in the generation of this signal
and the Matlab code for their simulation. We expect that the results obtained can
provide a useful reference material for future projects of the SARL’s team. In other
words, this project will concentrate only in the blocks labeled OFDM, D/A, and
Front End of figure..

ofdm-matlab-codes-complete-project

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Categories: Education Tags:

How to create your own torrent file and send it to friends?

March 13th, 2009 No comments

Torrents are great, they are the best way to share large files with your friends, or even with people you don’t know at all. But surprisingly enough, not many people create torrents when they need to share something. I have “a lot of” friends who know how to download torrents, but when they need to send me their latest 200MB vacation picture collection, they ask me to “get on msn”.

It’s not that I have anything against msn (although the file transfer sucks), but why don’t just use BitTorrent? Especially if you want to send something to more than one person, or if you want to share high quality HDTV files, because then you can share the bandwidth.

So how do you do this? Well it’s very simple. Open your favorite BitTorrent client and do the magic trick:

 file > create torrent

That’s all? Well almost. All you need to do now is put in the tracker info and tick some boxes. This can differ somewhat from client to client but it all comes down to the same thing.
uTorrent

utorrent bit torrent

1. File > Create new Torrent (or CTRL + N)
2. Select the files and or directories

3. Trackers: This is probably the hard part for most people. But it’s pretty easy, just put in one of the popular public trackers. You can use one or more trackers, but in general one is enough.

Here are some good trackers you can use:

http://open.tracker.thepiratebay.org/announce
http://www.torrent-downloads.to:2710/announce
http://denis.stalker.h3q.com:6969/announce
udp://denis.stalker.h3q.com:6969/announce
http://www.sumotracker.com/announce

Put one of these in the tracker box

4. Do NOT tick the private torrent box (unless you’re using a private tracker)

5. Save the torrent and send it to your friends.

Categories: Computer Hardware Tags:

Coca Cola Beverages Pakistan limited

March 11th, 2009 No comments

INTRODUCTION

The focus of this report is basically to analyze the different management functions at Coca cola beverages Pakistan limited Karachi. These functions include planning, organizing, leading and controlling.

International:

Coca-Cola laid the foundation of the beverage industry when it was formed in May 1886 in Atlanta. However it was not until 1895 that the idea of selling coke in bottles was introduced. With the passage of time Coca-Cola gained popularity and its product began to get recognized internationally. Thus from its mere beginning in 1886 Coca-Cola has now been transformed into a strong multinational with its product being currently recognized all over the world. Coca-Cola, in fact, has now become one of the most famous and widely consumed brands in the world. It has not only established its footings in the beverage industry but is currently heading the list of the most financially sound companies in the world.

Pakistan:

Although Coca-Cola is not a new name for the local market, Coca-Cola Beverages Pakistan Limited (CCBPL) began its operations on 26 May 1996 in Pakistan. Coca-Cola Beverages Private LTD (CCBPL) is a joint venture between Coca-Cola International, Fraser and Neeves Singapore and Package Ltd. Initially it acquired National Beverages LTD Karachi and later acquired International Beverages LTD Hyderabad .In May 1996 Fraser and Neeves, a Singapore based bottler of Coke, bought off the local bottlers in Karachi. Not long after it went on to acquire the bottling plants in Hyderabad as well. Since then coke has made an impressive impact on the local market by increasing it’s availability as well as its volume share. CCBPL has decided to expand its operations in Pakistan by buying other bottlers all over Pakistan. Implementing their plans of acquisitions of other plants they have recently acquired all the plants in Pakistan as they are inclined to give more attention to increase the market share in Pakistani market.

Coca-Cola.doc


Categories: Project Reports Tags:

Windows XP Tweaks

March 6th, 2009 No comments

Hacking Windows XP: Speed Up Your Network and Internet Access

Increasing network browsing speed Does your computer slow down when you browse your local area network and connect to other computers that are sharing data? One of the most common causes of this slowdown is a feature of Windows Explorer that looks for scheduled tasks on remote computers. This effort can take some time on some computers and can really slow down your browsing. The window with which you are browsing the network may appear to freeze momentarily, as the system is waiting for a response from the remote computer. Although this problem is a complex one, the solution is very simple. Instead of having to wait for the remote scheduled tasks, which is useless information to anyone who is not a system administrator remotely configuring scheduled tasks, you can disable this feature. In order to do this, you will have to hack the System Registry and delete a reference to a key so that this feature will not be loaded. To do this, follow these steps: Open up the Registry Editor by clicking the Start Menu and selecting Run. Then type regedit in the text box and click the OK button. Once the Registry Editor has loaded, expand the HKEY_LOCAL_MACHINE key. Next, expand Software and then Microsoft. Locate Windows and expand that as well. You will want to be editing the main system files, so expand CurrentVersion. Because this feature is a feature of the Windows component known as Explorer, expand the Explorer key. Next, you will want to modify the remote computer settings, so expand the RemoteComputer key and then expand the NameSpace key to show all of the features that are enabled when you browse to a remote computer. In the NameSpace folder you will find two entries. One is “{2227A2803AEA-1069-A2DE-08002B30309D}” which tells Explorer to show printers shared on the remote machine. The other, “{D6277990-4C6A-11CF-8D8700AA0060F5BF},” tells Explorer to show remote scheduled tasks. This is the one that you should delete. This can be done by right-clicking the name of the key and selecting Delete. Tip: If you have no use for viewing remote shared printers and are really only interested in shared files, consider deleting the printers key, “{2227A280-3AEA-1069-A2DE-08002B30309D}”, as well. This will also boost your browsing speed. Once you have deleted the key, you just need to restart and the changes will be in effect. Now your network computer browsing will be without needless delays.

Disabling unneeded protocols With every computer comes programs installed that you do not need. As with extra programs taking up space, extra protocols are just wasting your network connection and can actually slow it down. How is this possible? By default, a few different protocols are installed on your computer to allow for maximum compatibility with other computers on a network; these protocols each require bandwidth to operate. Most users will not use too many protocols, and their computers will use up a portion of their connection as they respond and transmit information for these protocols. Additionally, with extra protocols installed on your network adapter connected to the Internet, you increase your risk of security-related problems. One of the most common risks for broadband users is that they have the Client for Microsoft Networks networking protocol enabled on their connection. This protocol allows everyone in their neighborhood to connect to the users’ computers and view any files that they may be sharing. This fact alone should be a good enough reason for you to turn off the extra protocols. But with them disabled, you will also save a little bandwidth as well. Viewing protocols on your network adapters Viewing the protocols installed and active on your various network adapters is easy. Just follow these quick steps and you will be viewing them in no time: Right-click the My Network Places icon on the desktop or in the Start Menu and select Properties. If the My Network Places icon is not in either of those locations, then go to the Control Panel and click the Network Connections icon that is shown under the Classic view. Next, right-click the network adapter with which you want to view the network protocols and select Properties. This will bring up a list of the protocols installed as well as active on your adapter, as Figure 11-11 shows. The protocols that are installed but not active are indicated by the absence of a check in the checkbox.

Hacking Windows XP: Speeding Disk Access Disabling a specific protocol

Now that you have the list of installed and active protocols on your screen, you are ready to disable a protocol. To do so, just click the check box to remove the check. Then click the OK button and the protocol is no longer active on the network adapter. I highly recommend that you disable all protocols except for the TCP/IP protocol (also referred to as the Internet Protocol). Doing so will optimize your adapter for speed and security.

Be aware that if you remove the Client for Microsoft Networks protocol and the file-sharing protocol, you will no longer be able to share your files. Additionally, you will no longer be able to connect to remote computers to view their shared files. Also keep in mind that if you have multiple adapters in your machines, such as a wireless adapter, a wired network adapter, and a dialup modem, you will have to repeat the preceding instructions for each adapter.

Tweaking your Internet connection for speed Almost every computer user has different Internet connection conditions. Some users have very high-speed connections, while others have slow connections. Some users have high-speed connections using cable-based technologies, while others have high-speed connection through DSL-based

technologies. On top of these differences, some are located farther away from their local network switching station than others and have a higher latency (delay) on their connections because of the distance the data has to travel. All of these different connection conditions make every user unique. The TCP/IP protocol settings can be optimized for best speed under each of these situations. By default, Windows XP has these settings set in a “one size fits all” approach. As I mentioned earlier, Windows has to be abstract in certain areas because of its broad user base. Because of this approach, many users can fine-tune their settings to be optimal for their connection conditions. Doing so will optimize the data transferred so your network connection will be more efficient, leading to high speeds. With a little help from some fine online tools and software programs, you can test your Internet connection and decide what needs fine-tuning. The process of tweaking your Internet connection is not always easy, but it is doable. Caution: Before going any further, you are strongly advised to create a system restore point, so that if things go wrong, which is not very likely, you will have a backup. The next step in the tweaking process is to get all of the software that is needed. The main software program that you will use is called CableNut, which is developed by CableNut Software and is available for free at www.cablenut.com. CableNut is a great program that allows users to edit their Internet settings easily. Visit their Web page and download and install the latest copy.

Calculating settings for CableNut Once you have downloaded CableNut, you are ready to start getting information to use with the program. The first value that you will need to calculate is the latency of your connection when it is active. To do this, you will use the trace route command built into Windows XP. Follow these steps to get the latency value to use for your connection: First, open up a Command Prompt window. This can be done by clicking the Start Menu and selecting Run. Then type cmd in the text box and click the OK button. Once Command Prompt is loaded, you are ready for the next part. Because you will need to test your connection when it is active, you will need to find something large to download that will run the duration of the test, which will be approximately 30 seconds. I recommend that you head over to www.microsoft.com/downloads and find some huge file, such as the .NET SDK framework, which is over 100,000 KBs. For the test, you want a file big enough so it will be downloading throughout the whole test. Those of you on a dialup connection can pick a much smaller file than those on a high-speed connection. Once you have your download test file picked out, start the download and switch back to the Command Prompt window. In that window, type tracert www.tweakxp.com. During the test, you will see many times displayed in

milliseconds. After the test finishes, pick the highest time, as shown in Figure 11-12. This is the number that you will use as your latency. Also, feel free to cancel the download after the test is finished.

Entering the latency value into CableNut Now that you have the latency value calculated, you are ready to enter this information into a great online CableNut settings calculator written by Joe Zeiler, who is one of the talented moderators at the TweakXP.com support forums. Open up your Web browser and visit www.j79zlr.com/cablenutXP2k.php (the URL is case-sensitive!), then follow these steps to get the values to enter into CableNut: Once you have opened up the site, the first part of using the settings calculator is to select your connection type from the drop-down box. Next, you will have to do a little research and find out exactly what your upload and download speeds should be for your Internet connection. I had to contact Comcast, my ISP, to find out the exact values, because the values are not always advertised. Once, you get those values, make sure that they are in kilobits per second and not kilobytes per second (KB= kilobytes; Kb= kilobits), then enter them in the corresponding text boxes on the Web page.

Enter the latency value that you calculated earlier into the latency text box on the Web page and then click the Calculate button. After you hit the Compute Settings button, scroll down and you will see the values that were calculated. Now, you are almost done. Continue scrolling down until you see a button labeled CCS File Generator under the Cablenut setting files section. Click that button and a new window will pop up with some text in it. Make sure that you have any pop-up blockers disabled when you are using the calculator. Use the mouse and select all of the text and numbers that are displayed in the pop-up window. Right-click the mouse and select copy to copy all of the text on the page to the clipboard. Now open up Notepad from the Accessories folder. In the blank Notepad window, paste the contents of the clipboard by right-clicking the white background and selecting Paste. Once Notepad is displaying the information that you copied from the pop-

up window, all that is left is to save the file in the CableNut format. To do this, click the File menu bar item and select Save As. Then in the Save As Type drop-down box, select All Files. Key in myCableNutSettings.ccs in the file name text box. Specify the Save location, such as the desktop, and click the Save button. You are now finished with the calculations that will optimize your Internet connection. That wasn’t too hard now, was it?

Using CableNut to adjust settings Now that you have created your CableNut settings file, or will be using the 56K settings file, you are ready to start using CableNut. Follow these steps to import the new optimized settings into your system: Start up the CableNut application by opening the Start Menu and browsing to the CableNut folder and selecting the adjuster application. When CableNut has loaded, click the File menu bar item and select Open Custom Settings File. Navigate to where you saved your settings file, or if you are a 56K user, use the file that is on the companion CD, called 56K_CableNut.ccs, and then click the Open button. Now you will see the information boxes for all of the different parameters filled with your connection-specific information, as shown in Figure 11-13. The last step is to click the Save to Registry button and you are finished. After you click the Save button, reboot, and your new settings will be in effect.

Caution: According to www.j79zlr.com/cablenutXP2k.php, some of the CableNut settings can cause problems for a small amount of DSL customers. If you are experiencing network problems after optimizing your connection, use System Restore to revert to your last restore point. You may try the settings again, but blank out the MaxNormLookupMemory, MaxFreeTcbs, MaxHashTableSize, and FastSendDatagramThreshhold fields before applying. If you continue to have problems, or if you have problems with the directions and still want to optimize your connection, a great forum to get help on this topic is at www.broadbandnuts.com, or feel free to visit the support forum at www.intcube.com/forum

Categories: Windows XP Tags:

Nokia Codes Tips and Tricks

March 6th, 2009 No comments

To check the IMEI (International Mobile Equipment Identity)

Type-
*#06#
Information you get from the IMEI-
XX X
TAC FAC SNR SP

TAC = Type approval code
FAC = Final assembly code
SNR = Serial number
SP = Spare

To check the phones Software revision

Type-
*#0000#
Information you get from the Software revision-
V 05.31
18-02-99
NSE-3
1ST Line = Software revision
2ND Line = The date of the software release
3RD Line = Phone type

To enter the service menu

Type-
*#92702689# (*#WAR0ANTY#)
Serial number (IMEI)
Production date (MM/YY)
Purchase date (MM/YY) You can only enter the date once.
Date of last repair (0000=No repair)
Transfer user data to another Nokia phone via Infra-Red
Clock Stopping

To check weather your SIM Card supports clock stopping

Type-
*#746025625# (*#SIM0CLOCK#)

Revealing the Headphone and Car-Kit menus

Please note that if you do these next tricks, the new menus can’t be erased without retoring the factory default settings. To do these tricks you need to short-circuit the pins on the bottom of the phone next to where you plug in you charger.

1. To activate the “Headset” menu, you need to short-circuit pins “3” and “4”. After a short time the word “Headset” will be shown in the display. Menu 3-6 is now enabled.
2. To activate the “Car” menu, you need to short-circuit pins “4” and “5”. After a short time the word “Car” will be shown in the display. Menu 3-7 is now enabled.

The Reboot Trick

This should work on all software versions of the 6110.
1. Go to the Calendar (Menu-Cool
2. Make a note or reminder.
3. Enter some text into the edit box.
4. Hold “Clear” until the whole text is cleared, then press “Back”.
5. Press “0”. The main screen will now be showing but a space appears on the screen. (you can’t see it)
6. Enter 4 digits (e.g. 1234).
7. Use the down arrow to move the cursor to the left side of the numbers and the space (Down arrow twice).
8. Now enter 6 digits and press the call button.

Wait for a few seconds, the screen should start to flash and reboots. It should alsowork on other menus like the “Profiles” menu.

EFR CALL QUALITY

To activate EFR (Enhanced Full Rate) Enter the code-
*3370#
This improves call quality but decreases batterylife by about 5%
To deactivate it, Enter the code-
#3370#

THE JAMES BOND TRICK

If you short-circuit theleft middle and right pins on the bottom of the phone with all connections touching each other, the Nokia software hangs! The profile “Headset” will be activated. Before you do this just activate the “Automatic Answer” in the headset profile and set the ringing volume to “Mute”. Now you can use your phone for checking out what people are talking about in a room. Just place it under a table in a room and call it. The phone receives the call without ringing and you can listen to what people are saying.

NETWORK MONITOR

There is a hidden menu inside your Nokia phone. If you want to activate it, you’ll have to re-program some chips inside of your phone.
1. Check your software version. You can only continue if you have v4.33, v4.73 or v5.24.
2. Take apart the phone.
3. De-solder the EEPROM (ATMEL AT 24C64).
4. Read out the data with an EEPROM programmer and save it to a file (Backup).
5. If you have v.33 or v4.73, change the address “03B8” from “00” to “FF”.
6. If you have v5.24 then change the address “0378” from “00” to “FF”.
7. Write the new data to the EEPROM and solder it back to the phone,
8. Power on your phone and you should have “Netmonitor” enabled.
The Network Monitor gives you the following information.

Carrier number
MS RX Level in DBM
Received signal quality
MS TX power level
C1 (Path loss criterion, used for cell selection and reselection). The range is -99 to 99.
RTL (Radio link timeout).
Timeslot
Indication of the transmitter status
Information on the Network parameters.
TMSI (Temporary Mobile Subscriber Identity).
Cell identification (Cell ID, Number of cells being used).
MCC (Mobile country code)
MCN (Mobile network code)
LAC (Location area code)
Ciphering (On/Off)
Hopping (On/Off)
DTX (On/Off)
Discard cell barred information

CHECK SIM-LOCK

Note – If you bought your Nokia on UK Vodafone or UK Cellnet you do not need to check this because they both transmit on GSM900, and they don’t lock the phones. However if you bought your phone on UK Orange or UK One2one your phone may be blocked. The reason is that they both transmitt on GSM1800. To make a call on GSM1800 you need what is known as a “Dual band” phone. A dual band phone is able to transmit on both GSM900 and GSM1800, so they lock the phones so you can’t use it with any other network simcard. If you find that your phone is locked you can try different software to unlock it. (we havn’t found one that works yet), or you can ask your service provider who will gladly exchange the 10 digit code for about £35.
This is how to check the status of the 4 different locks. Aslo don’t try entering the wrong number, because after 3 times it will block the phone for good.

There are 4 different locks on your Nokia phone.
COUNTRY-LOCK
NETWORK-LOCK
PROVIDER-LOCK
SIMCARD-LOCK

The code to read out the sim-lock status of your phone is

#PW+(MASTERCODE)+(Y)#
# = DOUBLE-CROSS
W = PRESS “*” THREE TIMES
P = PRESS “*” FOUR TIMES
+ = PRESS “*” TWO TIMES
MASTERCODE = 1234567890
Y = NUMBER 1 TO 4
The master code is a secret code. The code has 10 digits, To read out the sim-lock status you can enter every combination you want!
“Y” Shows the status of the network-lock. Here you can enter a number from “1” to “4”. The “4” is for the sim-card lock.

SIM-LOCK CHECKS

#PW+1234567890+1# = GIVES PROVIDER-LOCK STATUS
#PW+1234567890+2# = GIVES NETWORK-LOCK STATUS
#PW+1234567890+3# = GIVES COUNTRY-LOCK STATUS
#PW+1234567890+4# = GIVES SIM-CARD-LOCK STATUS.

Categories: Computer Hardware Tags: