Design and Performance investigation of multiuser OCDMA network Parambir Singh, Manoj Kumar, Anurag Sharma Abstract-Optical Code Division Multiple Access (OCDMA) combines the large bandwidth of the fiber medium with the flexibility of the CDMA technique to achieve high speed connectivity. This paper presents the simulation module for OCDMA transmission and reception. The proposed network permits large number of users to communicate at high data rate. This paper describes a technology demonstrator for an incoherent optical code-division multi- ple-access scheme based on wavelength/time codes. The system supports 36 users operating at 10 Gsymbols/s/user while maintaining bit-error rate (BER) < 10-12 for the correctly decoded signal. Experiments support simulations which show that coherent beat noise, occurring between the signal and multiple access interference, ultimately limits system performance. Keywords-OCDMA; EDFA; SNR; BER; OC; FTTH; ——————————  —————————— 1. INTRODUCTION n next generation access networks, a symmetric multi- Gigabit Fiber-to-the-home (FTTH) service is required to meet the demands of future applications such as peer-to-peer, which includes video on demand, videoconferencing, high- definition TV (HD-TV), and voice over IP [1]. Optical code division multiple access (OCDMA) allows multiple users to share the same transmission media by assigning different op- tical codes (OCs) to different users,OCDMA is a promising aspirant for a new-generation broadband multiple access technique with unique features of full asynchronous transmis- sion, low latency access, and soft capacity on demand as well as optical layer security [1], [3]. OCDMA schemes are catego- rized as implementing the code through the optical field and relying through time slots and wavelengths with reliance on incoherent detection as shown in figure 1. Figure 1.Multiuser OCDMA Network Coherent schemes are susceptible to coherent beat noise that occurs when the correctly decoded signal temporally overlaps with the Multiple Access Interference (MAI) from other users [1].Signals from different encoders are coupled and each de- coder receives the sum of the encoded signals. If a given en- coder transmits a signal, only the decoder with the same code is capable of recovering it. Unwanted signals appear as noise to the decoder and are called multiple-access interference (MAI). MAI is the principal source of noise in OCDMA and is the limiting factor to system performance. In a well designed OCDMA network where MAI is over come, users can success- fully communicate asynchronously regardless of network traf- fic [7]. I ————————————————  Parambir Singh is currently pursuing masters degree program in Electronics and communication engineerin CT Institute Of Engineering, Management & Technology, Jalandhar, Punjab,india. E-mail:pmattewal@yahoo.com  Manoj Kumar is currently working as Director in CT Institute of Engineering, Management & Technology, Jalandhar, Punjab, India. E- mail:drmanojkumarindia@gmail.com  Anurag Sharma is currently working as Assistant Professor in CT Institute Of Engineering, Management & Technology, Jalandhar, Punjab, india. E- mail:er.anurags@gmail.com International Journal of Scientific & Engineering Research, Volume 4, Issue 7, July-2013 ISSN 2229-5518 2549 IJSER © 2013 http://www.ijser.org IJSER