OPNET Technologies
7255 Woodmont Avenue
Bethesda, MD 20814

Tel: 240-497-3000

Fax: 240-497-3001
E-mail: university@opnet.com
Web: www.opnet.com

OPNET is a registered
trademark of OPNET Technologies
© 2000 OPNET Technologies

University: University of Texas at Dallas
Name of Sponsoring Professor:
Murat Torlak
Erik Jonsson School of Engineering and Computer Science

1. Random Access CDMA Systems Simulation

Recently, large networks have become common place, and the allocation of resources has become critical. The most important and restricted resource is the system bandwidth for these networks. In order to cope with this problem  multiple access techniques are proposed.  Random Access CDMA systems are one of these techniques which have been widely used to efficiently allocate scarce radio communication channels (bandwidth) in such a way that users with bursty traffic can share the same frequency without significant degradation to the throughput. To address the scarce bandwidth problem we are designing a module to simulate Random Access CDMA systems. In this system the number of users, the length of spreading gain, power levels of the users will be promoted. So the user of this module can easily change them. Moreover, the user can determine whether the bits will be coded or uncoded. The simulation will provide means to observe and report the system specifications and performance of the network system for different circumstances. 

2. Preliminary Results

Our preliminary results are based on randomly located 50 transmitter and 1 receiver. Received powers of the users are equal. Randomly generated spreading code length is 30. In the figure, we compare the chip aligned simulation of the uncoded CDMA with the Improved Gaussion approximation for uncoded CDMA. 

2. Publications

-OPNET Simulation of Random Access CDMA Networks


-Simulation Based Analysis of Random Access CDMA Networks

(Journal of Naval Science and Engineering, 2004)

3. Contributed Models

-CDMA Random Access Model