Faculty Of Engineering Research Paper

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Browsing Faculty Of Engineering Research Paper by Author "21544"

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    Proposal of an optical CDMA random access protocol
    (2006) Malek Y.M.A.-E.; El-Sahn Z.A.; Shalaby H.M.H.; El-Badawy E.-S.A.; Department of Electrical Engineering; Faculty of Engineering; Alexandria University; Alexandria; 21544; Egypt; Department of Electrical Engineering; Faculty of Engineering; October University for Modem Sciences and Arts; Cairo; El-Dokki; Egypt
    A new random access protocol for optical code division multiple access (CDMA) communication systems is proposed. Stop & wait automatic repeat request (ARQ) is implemented at the optical link layer. A detailed state diagram and a mathematical model based on the equilibrium point analysis (EPA) technique are presented. Several performance measures are evaluated under different network parameters. We also compare the performance of the proposed protocol to that of the round robin receiver/transmitter (R 3T) protocol which is based on a go back-n technique. Finally, the proposed protocol is analyzed when a queuing subsystem is added. We prove by numerical analysis that the proposed protocol is less complex and significantly outperforms the R 3T protocol. Our results also reveal that the performance of the proposed protocol with correlation receivers is competitive to that of the R 3T protocol with chip-level receivers, which reduces the overall system cost. We finally show that a slight improvement in the protocol's performance can be achieved by only adding a single buffer to the system. The blocking probability is also reduced and the queuing delays that added to the total network latency are still acceptable.
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    The R 3T optical random access CDMA protocol with queuing subsystem
    (2006) El-Sahn Z.A.; Malek Y.M.A.-E.; Shalaby H.M.H.; El-Badawy E.-S.A.; Department of Electrical Engineering; Faculty of Engineering; Alexandria University; Alexandria; 21544; Egypt; Department of Electrical Engineering; Faculty of Engineering; October University for Modern Sciences and Arts; Cairo; El-Dokki; Egypt
    We introduce a queuing subsystem to an optical random access CDMA protocol, namely, the round robin receiver/transmitter (R 3T) protocol. A detailed state diagram is outlined and a mathematical model based on the equilibrium point analysis (EPA) is presented. In addition, the steady state system throughput, the average packet delay, and the blocking probability are derived and evaluated under several network parameters. We prove by numerical analysis that significant improvement in the protocol's performance can be achieved by only adding a single buffer to the system. The blocking probability is significantly reduced by a factor of 50 %. Our results also reveal that the modified R 3T protocol can support higher traffic loads. Further, queuing delays that added to the total network latency are acceptable.