Ram Chakka

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Chakka, R. and I. Mitrani, Heterogeneous multiprocessor systems with breakdowns: A model of a system with N parallel processors subject to occasional interruptions of service, and a common unbounded queue fed by a Poisson arrival stream, is analyzed in the steady state. The service, breakdown and repair characteristics may vary from processor to processor.(More)
A new queuing model is proposed for the performance evaluation of the High Speed Downlink Packet Access (HSDPA) protocol, with respect to a specified user, in UMTS networks. The model is based on the recently evolved MM &#931;<i><sup>&#922;</sup><sub>&#954;= </sub>CPP<sub>&#954;</sub>GEcLG</i>-queue<sup>1</sup>, in which the number of servers allocated to a(More)
Spectrum renting is an operation practice that can be applied to relieve the temporary capacity shortages of a specific service area in wireless cellular networks. However, works in the literature do not take into account the specific feature of the present wireless technology. That is, the separate blocks of user channels are defined in each frequency band(More)
The approximate solution technique for the main M/M/c retrial queue based on the homogenization of the model employs a quasi-birth-death (QBD) process in which the maximum retrial rate is restricted above a certain level. This approximated continuous-time Markov chain (CTMC) can be solved by the matrix-geometric method, which involves the computation of the(More)