Throughput analysis of 2-D OCDMA/pure ALOHA networks with access control and two user classes of variable length for multimedia traffic

In a previous research, the throughput of a 2-D optical code-division multiple-access (OCDMA)/unslotted ALOHA (U-ALOHA)/channel load sensing protocol network using an optical hard limiter and channel code was analyzed. This scheme assumed a fixed message length and one user class. However, the current and future themes of networks is multimedia traffic with variable message length and two different user classes of real-time and non-real-time. In this paper, we propose a 2-D OCDMA/U-ALOHA network with access control and two user classes of variable message length. We assume that the number of fixed-length packets in a message is geometrically distributed and perform access control by assigning two user classes with different access permission probabilities. The numerical results show the high priority user class (e.g. real-time data traffic) can maintain maximum system throughput under the heavy load at the expense of low priority user class (e.g. non-real-time data traffic). The proposed network protocol could obtain 100 Gbps and be a promising alternative for local area networks (LANs) and broadband optical access networks for larger capacity in response to fast growing of multimedia data traffic.