Charging and Failure Recovery Issues in UMTS

1
Charging and Failure Recovery Issues in UMTS
Student Sok-Ian Sou?????
Advisor Yi-Bing Lin???????
Research Topics for Failure Recovery
Issues Mobility Database Failure Restoration
using Checkpoint Schemes 1 We proposed two new
checkpoint schemes for failure restoration of HLR
in UMTS. An analytic model is developed to
compare these schemes. Our study provides
guidelines for selecting an appropriate
checkpoint scheme and parameters for various
traffic conditions. Broadcast Approach for UMTS
Mobility Database Recovery We described a
broadcast approach that allows the MS to detect
lost mobility management context in SGSN (in Fig.
1(a)), and therefore speeds up the process for
SGSN recovery. Based on our study, the network
operator can select the appropriate parameter
values in the broadcast approach.
Fig. 2 Numerical Results for Failure Recovery
Analysis
Research Topic for Charging Issues Prepaid
Mechanism of VoIP and Messaging Services 2 We
proposed a prepaid application server (PAS in
Fig. 3(g)) to handle both the prepaid calls and
messaging services in IMS. We describe a strategy
to determine if a prepaid message can be sent out
during a call session. An analytic model is
proposed to investigate the performance of this
strategy.
References 1 Sok-Ian Sou and Yi-Bing Lin,
Modeling of Mobility Database Failure Restoration
using Checkpoint Schemes. Accepted and to appear
in IEEE Transactions on Wireless Communications.
(SCI, EI) 2 Sok-Ian Sou, Yi-Bing Lin, Quincy Wu
and Jeu-Yih Jeng, Modeling of Prepaid Mechanism
of VoIP and Messaging Services. Accepted and to
appear in IEEE Transactions on Vehicular
Technology. (SCI, EI)