By Topic

An Internally Coded TH/OCDMA Scheme for Fiber Optic Communication Systems and Its Performance Analysis—Part I: Using Optical Orthogonal Code

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Karimi, M. ; Dept. of Electr. Eng., Sharif Univ. of Technol., Tehran ; Nasiri-Kenari, M.

In this paper, a new internally coded time-hopping optical code-division multiple-access (TH/OCDMA) scheme for fiber-optic communication systems is proposed, and its multiple-access performance is evaluated using optical orthogonal codes (OOCs). In the proposed method, the duration of each bit is divided into Ns frames, each one containing L chips. Two signature codes, namely, one pseudonoise (PN) sequence and one OOC, are assigned to each user. During each bit interval, based on the output of an channel encoder and the user's dedicated PN sequence, one of the Ns frames is selected, in which W pulses are transmitted in W chips, marked by the user's OOC. We consider three detectors at the receiver front end, namely, correlation, soft chip-level, and hard chip-level detectors. We evaluate the multiple-access performance of the system for each detector considering the effects of shot noise, dark current, and thermal noise. We compare the results with those obtained for the conventional OCDMA systems. Our numerical results indicate that, for the same bit rate and bandwidth, our proposed method substantially outperforms the conventional OCDMA system. Our results also show that the soft chip-level detector outperforms the other detection techniques in all cases considered

Published in:

Communications, IEEE Transactions on  (Volume:55 ,  Issue: 2 )