Performance Investigation of Green Wireless Systems

Introduction

 

The main objectives of the project are

1. To focus on achieving ‘Green’ reliable communications using relay structures by comparing the performance of entire cooperative relay structures with the conventionally existing techniques

2. To design a cooperative wireless network by creating a virtual MIMO systems and analyze its error performance in terms of symbol error probability

3. To develop an algorithm which enhances the performance of a wireless systems.

 

SEP of MPSK multiple relays using conventional selection combining	Performance analysis for multiple relays using proposed scheme

 

Achievements

 

This project has shown the possible benefits of a wireless transmission using cooperative diversity to increase the performance. The diversity is realized by building an ad-hoc network using a third station as a relay. The data is sent directly from the base to the mobile or via the relay station. Such a system has been simulated to see the performance of different diversity protocols and various combining methods. The AAF protocol has shown a better performance than the DAF protocol irrespective of the combining method used at the receiver. But it must be considered that no error correcting code was added to the transferred signal. Therefore, it was not possible to take full advantage of the DAF protocol. To get an idea of the potential of the DAF protocol the magic genie was introduced to simulate an error correcting code. The performance of a system using the DAF protocol in combination with a magic genie was much better than one using the AAF protocol. The choice of combining method has a big erect on the error rate at the receiver. When AAF is used at the relay station the easy to implement Equal Ratio Combining (ERC) shows some benefits compared to the single link transmission. If possible the Fixed Ratio Combining (FRC) should be used. This only need knowledge of the average channel quality, and shows a much better performance than the ERC. If knowledge of the current state of the channel quality is available more sophisticated combining methods can be used. The Enhanced Signal-to- Noise Ratio Combining (ESNRC) has shown a very good performance considering that a rough approximation of the channel quality is sufficient.

 

The location of the relay is crucial to the performance. The best performance was achieved when the relay is at equal distance from the sender and the destination or slightly closer to the former. In general the relay should not be too far from the line between the two stations.

 

• For further information please contact

 

Velammal Engineering College
Redhills-Ambattur Road,

Surapet, Chennai-66 Tamilnadu
Email : dhayavel2005@gmail.com