Performance analysis of CSMA/CD-DRC system

Multimedia communication systems must handle two types of messages, one is data type and the other is voice type. Data type messages can tolerate long er delay but voice type ones cannot. Though communication systems with huge capacity by optical fibers and ATM switches have little problem for multim edia communication, most of the present LANs cannot handle messages, especi ally voice type ones, satisfactorily because of their poor capacity. In thi s paper we propose a new protocol for LANs, CSMA/CD-DRC (Carrier Sense Mult iple Access with Collision Detection and Dynamic Retransmission Control). T his protocol is for the multimedia communication systems which must handle those two types of messages but do not have enough channel capacity, and co ntrols retransmission rates dynamically to achieve higher throughput and sh orter delay for voice type message. Moreover, we analyze the protocol in or der to confirm its performance. In analysis we derive Laplace-Stieltjes tra nsform (LST) of the probability distribution function (PDF) of the performa nce measures. Through LSTs, we can calculate not only averages but also hig her moments of performance measures as well as coefficients of variation. W e also present some numerical results, from which we find the proposed prot ocol can improve the system performance.