Browsing by Author "Yang, WZ"

Now showing 1 - 4 of 4

Performance of hot billing mobile prepaid service
(2001-07-01)
Chang, MF
;
Lin, YB
;
Yang, WZ
;
資訊工程學系
;
Department of Computer Science
Prepaid service has become an important mobile application with rapid growth for subscription rate in the recent years. Implementation of prepaid service may generate large network traffic that significantly affects the performance of a mobile network. This paper studies the hot billing solution for prepaid service. We investigate how the amount of prepaid credit and the Frequency of call detail record (CDR) transmissions affect network signaling and potential bad debt that a service provider may bear. Our study suggests that a prepaid service provider should encourage customers to buy large prepaid credits by giving them discounts. Furthermore. based on call traffic, an optimal CDR transmission frequency can be found by using our modeling technique. (C) 2001 Elsevier Science B.V. All rights reserved.
Performance of mobile prepaid and priority call services
(2002-02-01)
Chang, MF
;
Yang, WZ
;
資訊工程學系
;
Department of Computer Science
In this letter, we conduct simulation experiments to study a mobile phone system that provides priority and prepaid call services using service nodes. An analytical model for the nonprepaid and prepaid services has been developed to verify the computer simulations. We observe that there exists a threshold point such that beyond this point, increasing the number of mobile switching center ports (service node ports or the radio channels) does not improve the system performance. Furthermore, our results show that priority assignment schemes may significantly affect the operator's revenue.
Performance of service-node-based mobile prepaid service
(2002-05-01)
Chang, MF
;
Yang, WZ
;
Lin, YB
;
資訊工程學系
;
Department of Computer Science
In the recent years, mobile prepaid service has become an important mobile application with rapid growth of subscription rate. The most widely deployed prepaid solution today is the service node approach that deducts and updates the prepaid credit during a phone call. Implementation of the service node approach may generate large number of credit checks that significantly degrades the performance of a service node. We investigate how the number of credit checks affects the workload of the service node and the bad debt that a service provider may bear. We propose an analytic model to derive the optimal credit checking/updating frequency for the service node approach. The analytic analysis is validated against simulation experiments. Our study indicates that the number of credit checks increases rapidly when the call pattern is irregular. We also observe that in order to reduce the checking cost of the service node, the prepaid service provider should encourage the customer to make long calls by giving them discounts.
Priority call service on PCS networks
(1999-09-01)
Yang, WZ
;
Chang, MF
;
Lin, YB
;
資訊工程學系
;
Department of Computer Science
This paper studies the "priority call service" for personal communication services such as GSM cellular networks. With this service, a priority call requires is buffered in a waiting queue if no free channel is available. The buffered request can be served as soon as free channels become available. We develop an analytic model to evaluate the performance for the priority call service. In addition, computer simulations are conducted to verify the analytic model. The results indicate that priority calls experience very low new call blocking probability, as well as low call incompletion probability at the cost of increasing the force-termination probability.