In this paper, we propose a new Internet protocol (IP) traffic transmission architecture over optical code-division multiple-access (OCDMA) network capable of providing multiservice, multirate transmissions. The new architecture is independent of the OCDMA scheme employed. The main idea is to use multi-weight multi-length optical orthogonal code (MWML-OOC) as signature sequence of an incoherent OCDMA system to achieve multiservice and multirate transmissions. Furthermore, in order to evaluate the packet error rate (PER) of the proposed multiservice IP transmission, we derive a bit error rate (BER) expression of a MWML-OOC OCDMA system. The network performance is analyzed in terms of the channel utilization of the users' classes. The simulation results show that better performance is obtained by users defined with high-weight code. This is especially evident when the channel utilization is low. Keywords: multiservice, multirate IP Transmission, OCDMA, BER.
INTRODUCTIONThe recent advent of new Internet protocol (IP) based multimedia applications such as IPTV, e-learning, e-culture based on 3-D full-HD (high-definition), e-health, and so on, in ubiquitous Internet-based communication networks will eventually demand for differentiated service types and diversified data rates. These aspects most certainly will become an essential challenge for future optical networks [1]. IP has been the dominant protocol to deliver the recent multimedia applications services [2] and will continue to grow at an exponential rate as the demand for multimedia services across the Internet continues to expand. Nonetheless, IP routing operates electrically in the network layer and cannot be processed at a speed that matches the huge transmission capacity provided by optical fiber [2]. A potential solution to this challenging shortcoming has been proposed in [3], where we investigated a multirate, multiclass optical packet switch (OPS). In this approach, the bandwidth on a wavelength is divided into small fractions labelled with codes and assigned to different channels. However, like any emerging technology, there are still a few drawbacks to be addressed in OPS, such as contention resolution, to emerge it as a successful technology. Currently, optical code-division multiple-access (OCDMA) has become an attractive technology in all-optical networking, particularly due to features like easy addition of new users, possibility of differentiated-QoS at the physical layer, and support to bursty and asynchronous networks traffic, i.e., IP traffic nature [1], [2], [4]. In addition, OCDMA provides more immunity to packet collisions than dynamic bandwidth allocation in time-division multiple-access schemes [5]. Moreover, OCDMA has a teletraffic capacity larger than wavelength-division multiple-access, especially when bursty traffic is carried out [6].In this paper, we propose and introduce a new multiservice, multirate IP traffic network architecture over OCDMA. The proposed architecture is independent of the OCDMA scheme or spreading code e...
