• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.5
• /
• pp.451-457
• /
• 1991

Four computational algorithms are discussed and compared in terms of complexity, required memory, and the number of channels which calculate the blocking probabilities in the two-dimensional multi-slot connection traffic. The overflow and underflow problems can be circumvented, and thus blocking probabilities can be calculated even up to 10000 channels, by the proposed last algorithm. This algorithm is utilized in calculating the blocking probabilities for I-slot and 6-slots calls. And the results of the simulation by the SLAM-II are compared with those of the analytic calculation.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.22 no.4
• /
• pp.173-182
• /
• 1997

In this paper, an efficient dynamic channel assignment scheme is suggested, which consists of two types of channel allocation strategies : ordinary channel allocation strategy and channel reallocation strategy. An analysis on the handoff probabilities of handoff and new calls is also performed, and using the analyzed handoff probability, the presented scheme is compared with other existing schemes in terms of three types of blocking probabilities- new call blocking probability, handoff call blocking probability, and network blocking probability (incomplete service probability). Simulation results show that the presented scheme significantly reduces those blocking probabilities over the existing schemes. Furthermore, the scheme has much smaller number of reallocation than other schemes.

• Korean Management Science Review
• /
• v.10 no.1
• /
• pp.127-137
• /
• 1993

The blocking probabilities of nx64Kb/s multi-slot calls are generally much higher than that of single slot calls. In order to improve these blocking probabilities of multi-slot calls, we propose a scheme which searches the different numbers of time slots for different types of calls. We analyze the performance of our scheme in a double-buffered time-space-time switching network which accommodates multi-slot calls as well as single-slot calls. The proposed method yields the reduced blocking probabilities, the increased traffic handling capacity and teh reduced CPU processing load, compared with those of the conventional methods.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.1-11
• /
• 1991

Multi rate circuit switching ISDN which assumes a star topology consisting of LANs(local area networks) interconnected through a backbone MAN (metropolitan area network) is considered. The stations are classified into two categories data and voice stations they are characterized by different arrival rate and session-length (holding time) statistics. We first model the data and voice terminals as finite-source stations and derive analytically exact expressions for the end-to-end blocking probabilities. For more exact evaluation, these probabilities are calculated in terms of three components:circuit blocking probability, destination busy probability and concurrent busy probability. For large size systems, we develop an develop an iterative algorithm that provides a computationally efficient and fast method for the calculation of the end-to-end blocking probabilities.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.958-961
• /
• 1987

Four computational algorithms are discussed and compared which calculate the blocking probabilities in the multi-slot connection traffic for the wide-band services. The computational complexity and time can be significantly reduced, and the overflow and underflow problem can be circumvented as well, by a newly proposed algorithm, the last one.

• Journal of the Korea Society for Simulation
• /
• v.17 no.4
• /
• pp.241-247
• /
• 2008

In this study we consider an M/D/1 queue with a finite buffer. Due to the finiteness of the buffer capacity arriving customers can not join the system and turn away without service when the buffer is full. Even though a computational method for blocking probabilities in an M/D/1/K queue is already known, it is very complex to use. The aim of this study is to propose a new way to compute blocking probability by using (max,+)-algebra. Our approach provide a totally different and easier way to compute blocking probabilities and it is, moreover, immediately applicable to more generous queueing systems.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.1
• /
• pp.21-27
• /
• 1998

In this paper we apply routing algorithms in circuit switched networks to B-ISDN networks and investigate the performance. B-ISDN supports a wide range of services with hetrogeneous bandwidth requirements. We assume that the network supports D classes of traffic. It is modeled as a finite D dimensional Markov chain. A call is blocked on arrival if the required bandwidth is not available on the route. The shortest path routing, alternate routing and trunk reservation are considered for performance comparison. We also consider trunk reservation with restricted access control where the network reserves certain amount of bandwidths for one class of traffic that assumes a higher transmission priority. Through the method of successive iterations, we obtain the steady state equilibrium probabilities and call blocking probabilities for dynamic routing. The results can be used to design a B-ISDN network that improves network connection availability and efficiency while simultaneously reducing the network costs.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.1
• /
• pp.1-10
• /
• 1989

In this paper a computional algorithm which can circumvent the overflow and underflow problems is proposed for calculating the blocking probabilities in the multi-dimensional multi-slot connection trafficd. This algorithm is applied to the analysis of blocking probabolotoes in the single time switches and transmission systems with varying the total number of time slots and trunk lines, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.4
• /
• pp.17-24
• /
• 2004

Call blocking probabilities of streaming data service in CDMA system with access point(AP) of WLAN are analyzed for different cell geometry of base station and AP and queuing is modeled. The considered system leads to successful handoffs between the APs of WLAN. Blocking probabilities are enumerated as a function for ratio of base station and AP sizes, their locations and the number of buffer in the queue. Results show that blocking probability is not influenced by base station and AP locations but mainly by ratio of their sizes. For CDMA system of radius 100m, 5 buffers in the queue and 7㏈ noise rise(NR), in order to obtain 1% call blocking probability, a cell with hot spot of radius 20m has more 0.6Erlang than that of radius 60m.

• Journal of the Korean Mathematical Society
• /
• v.35 no.3
• /
• pp.539-557
• /
• 1998

This paper is concerned with the performance evaluation of loss networks. We shall review the Erlang Fixed Point (EFP) method for estimating the blocking probabilities, which is based on an assumption that links are blocked independently. For networks with linear structure, the behaviour of adjacent links can be highly correlated. We shall give particular attention to recently-developed fixed-point methods which specifically account for the dependencies between neighbouring links. For the network considered here, namely a ring network with two types of traffic, these methods produce relative errors typically $10^{-5}$ of that found using the basic EFP approximation.