Woo-Yong Lee

Design and analysis of hybrid approach to mobile TV service over WiMAX network

In this paper, we propose a novel mobile TV service over WiMAX network. Instead of using broadcasting method or unicasting scheme, we use a hybrid approach that exploits adaptive modulation and coding (AMC) gain in unicast scheme and at the same time accommodates arbitrary many users watching the same channel like broadcast method, which enables to increase wireless capacity for mobile TV service. In addition, we present a WiMAX design tool, based on an analytical model, maximizing WiMAX capacity and study the influence of the most important traffic and system parameters. The analytical model can provide an accurate estimate of the amount of bandwidth for WiMAX TV service.

Framework and analysis of switched wireless video services over mobile WiMAX network

This paper presents a switched wireless video service which can swell the capacity by serving video channels through switched broadcast, switched multicast, or switched unicast instead of standard broadcast schemes. We extend the switched video service into wireless environment and then exploit WiMAX adaptive modulation and coding gain.

Enhanced upstream scheduling algorithm for variable bit rate VoIP service over hybrid fiber coaxial network

In this paper, we enhance the existing upstream scheduling algorithm for VoIP service in data-over-cable system interface specification (DOCSIS) MAC protocol which is, called unsolicited grant service with activity detection (UGS-AD), not able to efficiently support various VoIP codecs with variable bit rate (VBR) and silence suppression over the shared medium hybrid-fiber-coaxial (HFC) network. We modify the UGS-AD to minimize a waste of uplink resources for supporting the VBR VoIP service. This proposed scheme is compared with the existing UGS-AD through the capacity analysis. Results show that our proposed algorithm can support more up to 59% voice users compared with the existing UGS-AD.