Vincent Feng

WGSN: WLAN-based GPRS Support Node with Push Mechanism

This paper proposes wireless LAN (WLAN)-based GPRS Support Node (WGSN), as a solution for integrating Third Generation (3G) and WLAN services. We show that the 3G mechanisms can be re-used for WLAN user authentication and network access without introducing new procedures and without modifying the existing 3G network components. We describe the WGSN features and show how they are designed and implemented. To reduce the power consumption and computation complexity of a mobile station (MS), the WGSN applications may not be activated in the MS if they are not used. For an MS-terminated application, a push mechanism is implemented in WGSN, which automatically activates the application at the MS side. An analytic model is proposed to investigate the requirements on the WGSN transmission delay of the push operation. A WGSN prototype has been implemented in the Industrial Technology Research Institute and National Chiao-Tung University Joint Research Center.

GPRS-based WLAN authentication and auto-configuration

This paper proposes an authentication and auto-configuration mechanism for wireless LAN (WLAN) based on short message service of mobile telecommunications network. Our approach automates the authentication and WLAN configuration setup procedure without involving the users.

Design and implementation of a softswitch for third generation mobile all-IP network

This chapter describes the design and implementation of a softswitch for UMTS developed by Computer and Communication Research Laboratory (CCL) of Industrial Technology Research Institute (ITRI). This softswitch can be utilized as call agent (media gateway controller) for the third generation mobile all-IP network such as UMTS. The CCL Softswitch follows the reference architecture proposed by International Softswitch Consortium. In our approach, the Intelligent Network (IN) call model is implemented to interwork with existing IN devices. We design protocol adapter modules and service provider interface to ensure that multiple VoIP protocols can be supported without modifying the core of the softswitch. Furthermore, the message flows of call setup, call transfer and inter-softswitch call are described to show the feasibility of the softswitch.

Performance analysis of multicarrier CDMA multiuser detection with channel mismatch

Using the replica method originally developed for statistical physics, we provide asymptotic (large-system limit) so- lutions to the output signal-to-interference ratio (SIR) of the mul- tiuser detections (MUDs) with channel mismatch in multi-carrier code-division-multiple-access (MC-CDMA) systems. Among sys- tem performances of the MUDs, we cover both 1) linear detectors such as the linear minimum mean-square error (LMMSE) detec- tor, the linear decorrelator (LDD), and matched-filter (MF) de- tector, and 2) nonlinear detector such as the maximum posterior marginal (MPM) detector and the maximum a posteriori (MAP) detector. Through numerical experiments for finite systems, we show that the asymptotic solutions can produce highly accurate results for MC-CDMA systems.