Packet switching unslotted optical CDMA system with variable length data traffic: Throughput, delay and stability analysis

In this paper we study unslotted ALOHA optical code division multiple access (CDMA) packet switching local area network (LAN). The system uses on-off keying (OOK) and M-ary overlapping pulse position modulation (OPPM) as signaling schemes. Generalized and strict optical orthogonal codes (OOC) are used to implement CDMA concept. The generated packets are assumed to have variable length. The impact of system parameters on key performance bench marks such as throughput and delay is analyzed. We also study the stability of the network. It is shown that OPPM signaling based on generalized OOC not only improves the network average delay and throughput, but also substantially improves stability of the network. In fact, OPPM signaling employing generalized OOC makes the system stable for a wide range of Media Access Control (MAC) layer parameters.