3 research outputs found
Π‘ΠΈΡΡΠ΅ΠΌΠ° ΠΌΠ°ΡΡΠΎΠ²ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ Ρ ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΠ΅ΠΌ ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠ°, ΠΏΠΎΠ²ΡΠΎΡΠ½ΡΠΌΠΈ Π²ΡΠ·ΠΎΠ²Π°ΠΌΠΈ ΠΈ Π½Π΅ΡΠ΅ΡΠΏΠ΅Π»ΠΈΠ²ΠΎΡΡΡΡ Π·Π°ΠΏΡΠΎΡΠΎΠ²
Objectives. The problem of constructing and investigating a mathematical model of a stochastic system with processor sharing, repeated calls, and customer impatience is considered. This system is formalized in the form of a queueing system. The operation of the queue is described in terms of multi-dimensional Markov chain. A condition for the existence of a stationary distribution is found, and algorithms for calculating the stationary distribution and stationary performance characteristics of the system are proposed.Methods. Methods of probability theory, queueing theory and matrix theory are used.Results. The steady state operation of a queueing system with repeated calls, processor sharing and two types of customers arriving in a marked Markovian arrival process is studied. The channel bandwidth is divided between two types of customers in a certain proportion, and the number of customers of each type simultaneously located on the server is limited. Customers of one of the types that have made all the channels assigned to them busy leave the system unserved with some probability and, with an additional probability, go to the orbit of infinite size, from where they make attempts to get service at random time intervals. Customers of the second type, which caused all the channels assigned to them to be busy, are lost. Customers in orbit show impatience: each of them can leave orbit forever if the time of its stay in orbit exceeds some random time distributed according to an exponential law. Service times of customers of different types are distributed according to the phase law with different parameters. The operation of the system is described in terms of a multi-dimensional Markov chain. It is proved that for any values of the system parameters this chain has a stationary distribution. Algorithms for calculating the stationary distribution and a number of performance measures of the system are proposed. The results of the study can be used to simulate the operation of a fixed capacity cell in a wireless cellular communication network and other real systems operating in the processor sharing mode.Π¦Π΅Π»ΠΈ. Π Π°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΡΡΡ Π·Π°Π΄Π°ΡΠ° ΠΏΠΎΡΡΡΠΎΠ΅Π½ΠΈΡ ΠΈ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΌΠΎΠ΄Π΅Π»ΠΈ ΡΡΠΎΡ
Π°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ Ρ ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΠ΅ΠΌ ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠ°, ΠΏΠΎΠ²ΡΠΎΡΠ½ΡΠΌΠΈ Π²ΡΠ·ΠΎΠ²Π°ΠΌΠΈ ΠΈ Π½Π΅ΡΠ΅ΡΠΏΠ΅Π»ΠΈΠ²ΠΎΡΡΡΡ Π·Π°ΠΏΡΠΎΡΠΎΠ². ΠΠ°Π½Π½Π°Ρ ΡΠΈΡΡΠ΅ΠΌΠ° ΡΠΎΡΠΌΠ°Π»ΠΈΠ·ΠΎΠ²Π°Π½Π° Π² Π²ΠΈΠ΄Π΅ ΡΠΈΡΡΠ΅ΠΌΡ ΠΌΠ°ΡΡΠΎΠ²ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ, ΠΏΠΎΡΡΡΠΎΠ΅Π½ ΠΏΡΠΎΡΠ΅ΡΡ ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠΈΡΡΠ΅ΠΌΡ, Π½Π°ΠΉΠ΄Π΅Π½ΠΎ ΡΡΠ»ΠΎΠ²ΠΈΠ΅ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΡ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΈ ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Ρ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ Π²ΡΡΠΈΡΠ»Π΅Π½ΠΈΡ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΈ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΡΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΡΠΈΡΡΠ΅ΠΌΡ.ΠΠ΅ΡΠΎΠ΄Ρ. ΠΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ ΠΌΠ΅ΡΠΎΠ΄Ρ ΡΠ΅ΠΎΡΠΈΠΈ Π²Π΅ΡΠΎΡΡΠ½ΠΎΡΡΠ΅ΠΉ, ΡΠ΅ΠΎΡΠΈΠΈ ΠΌΠ°ΡΡΠΎΠ²ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ ΠΈ ΡΠ΅ΠΎΡΠΈΠΈ ΠΌΠ°ΡΡΠΈΡ.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. Π€ΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠΏΠΈΡΠ°Π½ΠΎ Π² ΡΠ΅ΡΠΌΠΈΠ½Π°Ρ
ΠΌΠ½ΠΎΠ³ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ ΡΠ΅ΠΏΠΈ ΠΠ°ΡΠΊΠΎΠ²Π°. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΡΡΠ° ΡΠ΅ΠΏΡ ΠΈΠΌΠ΅Π΅Ρ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΠΎΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅, ΡΠΎΠ²ΠΏΠ°Π΄Π°ΡΡΠ΅Π΅ Ρ ΡΡΠ³ΠΎΠ΄ΠΈΡΠ΅ΡΠΊΠΈΠΌ, ΠΏΡΠΈ Π»ΡΠ±ΡΡ
ΠΏΡΠΈΠ΅ΠΌΠ»Π΅ΠΌΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ², ΠΎΠΏΠΈΡΡΠ²Π°ΡΡΠΈΡ
Π²Ρ
ΠΎΠ΄Π½ΠΎΠΉ ΠΏΠΎΡΠΎΠΊ, Π²ΡΠ΅ΠΌΡ ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ, ΠΏΡΠΎΡΠ΅ΡΡ ΠΏΠΎΠ²ΡΠΎΡΠ½ΡΡ
Π²ΡΠ·ΠΎΠ²ΠΎΠ² ΠΈ ΠΏΡΠΎΡΠ΅ΡΡ ΡΡ
ΠΎΠ΄Π° Π·Π°ΠΏΡΠΎΡΠΎΠ² ΠΈΠ· ΡΠΈΡΡΠ΅ΠΌΡ Π²ΡΠ»Π΅Π΄ΡΡΠ²ΠΈΠ΅ Π½Π΅ΡΠ΅ΡΠΏΠ΅Π»ΠΈΠ²ΠΎΡΡΠΈ.ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΡΠΉ ΡΠ΅ΠΆΠΈΠΌ ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠΈΡΡΠ΅ΠΌΡ ΠΌΠ°ΡΡΠΎΠ²ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ Ρ ΠΏΠΎΠ²ΡΠΎΡΠ½ΡΠΌΠΈ Π²ΡΠ·ΠΎΠ²Π°ΠΌΠΈ, ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΠ΅ΠΌ ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠ° ΠΈ Π΄Π²ΡΠΌΡ ΡΠΈΠΏΠ°ΠΌΠΈ Π·Π°ΠΏΡΠΎΡΠΎΠ², ΠΏΠΎΡΡΡΠΏΠ°ΡΡΠΈΡ
Π² ΡΠΈΡΡΠ΅ΠΌΡ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΌΠ°ΡΠΊΠΈΡΠΎΠ²Π°Π½Π½ΡΠΌ ΠΌΠ°ΡΠΊΠΎΠ²ΡΠΊΠΈΠΌ ΠΏΠΎΡΠΎΠΊΠΎΠΌ. ΠΡΠΎΠΏΡΡΠΊΠ½Π°Ρ ΡΠΏΠΎΡΠΎΠ±Π½ΠΎΡΡΡ ΠΊΠ°Π½Π°Π»Π° Π΄Π΅Π»ΠΈΡΡΡ ΠΌΠ΅ΠΆΠ΄Ρ Π·Π°ΠΏΡΠΎΡΠ°ΠΌΠΈ Π΄Π²ΡΡ
ΡΠΈΠΏΠΎΠ² Π² Π½Π΅ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΏΡΠΎΠΏΠΎΡΡΠΈΠΈ, Π° ΡΠΈΡΠ»ΠΎ Π·Π°ΠΏΡΠΎΡΠΎΠ² ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΠΈΠ· ΡΠΈΠΏΠΎΠ², ΠΎΠ΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎ Π½Π°Ρ
ΠΎΠ΄ΡΡΠΈΡ
ΡΡ Π½Π° ΠΏΡΠΈΠ±ΠΎΡΠ΅, ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΎ. ΠΠ°ΠΏΡΠΎΡΡ ΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΈΠ· ΡΠΈΠΏΠΎΠ², Π·Π°ΡΡΠ°Π²ΡΠΈΠ΅ Π²ΡΠ΅ ΠΎΡΠ²Π΅Π΄Π΅Π½Π½ΡΠ΅ Π΄Π»Ρ Π½ΠΈΡ
ΠΊΠ°Π½Π°Π»Ρ Π·Π°Π½ΡΡΡΠΌΠΈ, Ρ Π½Π΅ΠΊΠΎΡΠΎΡΠΎΠΉ Π²Π΅ΡΠΎΡΡΠ½ΠΎΡΡΡΡ ΡΡ
ΠΎΠ΄ΡΡ ΠΈΠ· ΡΠΈΡΡΠ΅ΠΌΡ Π½Π΅ΠΎΠ±ΡΠ»ΡΠΆΠ΅Π½Π½ΡΠΌΠΈ ΠΈ Ρ Π΄ΠΎΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ Π²Π΅ΡΠΎΡΡΠ½ΠΎΡΡΡΡ ΠΈΠ΄ΡΡ Π½Π° ΠΎΡΠ±ΠΈΡΡ Π±Π΅ΡΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ΅ΠΌΠ°, ΠΎΡΠΊΡΠ΄Π° Π΄Π΅Π»Π°ΡΡ ΠΏΠΎΠΏΡΡΠΊΠΈ ΠΏΠΎΠΏΠ°ΡΡΡ Π½Π° ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΠ΅ ΡΠ΅ΡΠ΅Π· ΡΠ»ΡΡΠ°ΠΉΠ½ΡΠ΅ ΠΏΡΠΎΠΌΠ΅ΠΆΡΡΠΊΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ. ΠΠ°ΠΏΡΠΎΡΡ Π²ΡΠΎΡΠΎΠ³ΠΎ ΡΠΈΠΏΠ°, Π·Π°ΡΡΠ°Π²ΡΠΈΠ΅ Π²ΡΠ΅ ΠΎΡΠ²Π΅Π΄Π΅Π½Π½ΡΠ΅ Π΄Π»Ρ Π½ΠΈΡ
ΠΊΠ°Π½Π°Π»Ρ Π·Π°Π½ΡΡΡΠΌΠΈ, ΡΠ΅ΡΡΡΡΡΡ. ΠΠ°ΠΏΡΠΎΡΡ, Π½Π°Ρ
ΠΎΠ΄ΡΡΠΈΠ΅ΡΡ Π½Π° ΠΎΡΠ±ΠΈΡΠ΅, ΠΏΡΠΎΡΠ²Π»ΡΡΡ Π½Π΅ΡΠ΅ΡΠΏΠ΅Π»ΠΈΠ²ΠΎΡΡΡ: ΠΊΠ°ΠΆΠ΄ΡΠΉ ΠΈΠ· Π½ΠΈΡ
ΠΌΠΎΠΆΠ΅Ρ ΠΏΠΎΠΊΠΈΠ½ΡΡΡ ΠΎΡΠ±ΠΈΡΡ Π½Π°Π²ΡΠ΅Π³Π΄Π° ΠΏΠΎ ΠΈΡΡΠ΅ΡΠ΅Π½ΠΈΠΈ ΡΠΊΡΠΏΠΎΠ½Π΅Π½ΡΠΈΠ°Π»ΡΠ½ΠΎ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΠ³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΠΏΡΠΈ ΡΡΠ»ΠΎΠ²ΠΈΠΈ, ΡΡΠΎ ΠΎΠ½ Π½Π΅ ΠΏΠΎΠΏΠ°Π΄Π΅Ρ Π½Π° ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΠ΅ Π·Π° ΡΡΠΎ Π²ΡΠ΅ΠΌΡ. ΠΡΠ΅ΠΌΠ΅Π½Π° ΠΎΠ±ΡΠ»ΡΠΆΠΈΠ²Π°Π½ΠΈΡ Π·Π°ΠΏΡΠΎΡΠΎΠ² ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΠΏΠΎ ΡΠ°Π·ΠΎΠ²ΠΎΠΌΡ Π·Π°ΠΊΠΎΠ½Ρ Ρ ΡΠ°Π·Π½ΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ. Π€ΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠΏΠΈΡΠ°Π½ΠΎ Π² ΡΠ΅ΡΠΌΠΈΠ½Π°Ρ
ΠΌΠ½ΠΎΠ³ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ ΡΠ΅ΠΏΠΈ ΠΠ°ΡΠΊΠΎΠ²Π°. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΈ Π»ΡΠ±ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΠΈΡΡΠ΅ΠΌΡ ΡΡΠ° ΡΠ΅ΠΏΡ ΠΈΠΌΠ΅Π΅Ρ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΠΎΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Ρ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ Π²ΡΡΠΈΡΠ»Π΅Π½ΠΈΡ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΈ ΡΡΠ΄Π° Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΡΠΈΡΡΠ΅ΠΌΡ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΌΠΎΠ³ΡΡ Π±ΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½Ρ Π΄Π»Ρ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ°Π±ΠΎΡΡ ΡΠΎΡΡ ΡΠΈΠΊΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ Π΅ΠΌΠΊΠΎΡΡΠΈ Π² Π±Π΅ΡΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΠΉ ΡΠΎΡΠΎΠ²ΠΎΠΉ ΡΠ΅ΡΠΈ ΡΠ²ΡΠ·ΠΈ ΠΈ Π΄ΡΡΠ³ΠΈΡ
ΡΠ΅Π°Π»ΡΠ½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ, ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΡΡΡΠΈΡ
Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠ°
Analysis of a retrial queue with limited processor sharing operating in the random environment
Queueing system with limited processor sharing, which operates in the Markovian random environment, is considered. Parameters of the system (pattern of the arrival rate, capacity of the server, i.e., the number of customers than can share the server simultaneously, the service intensity, the impatience rate, etc.) depend on the state of the random environment. Customers arriving when the server capacity is exhausted join orbit and retry for service later. The stationary distribution of the system states (including the number of customers in orbit and in service) is computed and expressions for the key performance measures of the system are derived. Numerical example illustrates possibility of optimal adjustment of the server capacity to the state of the random environment. Β© IFIP International Federation for Information Processing 2017
Analysis of a retrial queue with limited processor sharing operating in the random environment
Queueing system with limited processor sharing, which operates in the Markovian random environment, is considered. Parameters of the system (pattern of the arrival rate, capacity of the server, i.e., the number of customers than can share the server simultaneously, the service intensity, the impatience rate, etc.) depend on the state of the random environment. Customers arriving when the server capacity is exhausted join orbit and retry for service later. The stationary distribution of the system states (including the number of customers in orbit and in service) is computed and expressions for the key performance measures of the system are derived. Numerical example illustrates possibility of optimal adjustment of the server capacity to the state of the random environment. Β© IFIP International Federation for Information Processing 2017