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MULTIUSER DETECTION IN CDMA SYSTEMS

Overview:
In this project Multiuser Detection (MUD) in DS-CDMA for synchronous communication is studied in AWGN channel. Various suboptimal, linear and non linear MUD approaches are studied and implemented in Matlab. Performance analysis of various detectors is done through simulation results and compared to the conventional detector. To the end, conclusions are drawn through theoretical and simulation results.

After completing this project, it has been observed that various MUD algorithms perform better than conventional detector in the presence of MAI. The near far problem which was an important issue in wireless communication has been resolved to some extent by effective power control. Suboptimum detectors have reduced the complexity without compromising the performance. Linear detectors like decorrelating detector, although show some problem for long data sequences but their performance is very good even in the presence of Multi-Access Interference. Adaptive methods for MMSE are very easy and require very few information to implement but show great performance.

Student & Supervisor:

Presented by: Imran Babar
Supervisor:Dr. Qasim Mehmood

Evaluation of Different Video Conferencing Systems

Overview:

In this project various Video Conferencing technology, implementation of different technologies and their comparison are studied. This study is about different protocols and standards that are used in video conferencing, and to compare the difference in the video performance. The study includes the devices and the services provided by these technologies. We have also explored the issues related to the cost, quality of service (QoS), reliability and most important security. Our work also includes the advantages of video conferencing technologies in different fields of life. We have also considered the deployment of video conferencing technology in different educational institutes of Pakistan.

Objectives that we have covered:

• To evaluate and compare different types of Video Conferencing solutions
• Web based video conference, webex.com and dimdim.com and also desktop video conferencing and evaluation of VLC player.
• We studied various protocols about video conferencing, applications. Making an interface using stickam.com through which teachers and students can communicate.

Video conferencing stands out as a rich communications technology that offers new and interesting possibilities for distance education. This is because of its ability to combine diverse endpoints into a single setting, where audio and/or video clips, graphics, animations and computer applications from each can be shared in real-time, thus enabling whole new levels of interaction and precipitating entirely new communication and ideas. A simple computer user can use simple tools like VLC player and stickam and can make a very good video conferencing system.

Students & Supervisor:

Presented by: Arslan Ahmad & Sikandar Hafeez

Supervisor: Dr. Jamil Ahmad (Dean)

Diversity Techniques for MIMO OFDM systems

Overview
Time-varying multi-path fading degrades the BER performance at the receiver. Multiple delayed versions of the transmitted signal due to the reflections of buildings, roads, and other obstacles reach at receiver, each of these paths has different attenuation and time delay sometimes signal add constructively, sometimes destructively hence fading makes wireless communication a harder problem. Diversity schemes attempt to reduce this problem by finding independently faded paths in the mobile radio channel.
For instance in W-LANs in some cases there might be chances that a workstation may be located on a place where the channel may have very less multi-path components hence the effect of channel become flat fading, this problem can not be solved even with other techniques like interleaving etc because when complete data goes in the deep fade nothing can be done with it, here to solve such issues a mechanism able to convert the flat fading into frequency selective fading environment is needed. Cyclic Delay Diversity is a solution for this sort of problem as CDD converts frequency flat channel into frequency selective channel. In this project we have simulated CDD, Maximal Ratio Combining (used to optimize the diversity combining by selecting cyclic shifts and weight factors based on the known channel state information and the Alamouti