Hee-Wook Kim

A Cooperative Transmit Diversity Scheme for Mobile Satellite Broadcasting Systems

In this paper, we propose an efficient cooperative diversity scheme for mobile satellite multimedia broadcasting systems. The proposed scheme is a transmit diversity technique to adapt different channel environments, and thus we do not need any channel quality information from the return link. In the proposed scheme, we utilize space-time block coding (STBC) and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system with several repeaters. The satellite and several repeaters operate in unison to send the encoded signals, so that the receiver may realize diversity gain. The simulation results demonstrate that the proposed scheme can provide highly improved performance.

Joint channel and data estimation for time hopping-ultrawide bandwidth multiple access system in multipath channel

We consider U proper detection schemes .for time hopping (TH)-iiltru wide handwidth (U WB) mitltiple access (MA) .swtei?o in mirltipath channel. First, we upplv the well-known niitiiniion mean sqirare error (MMSE) mziltiiisev detector (MUD). Next. we propose the improved detection scheme. which /ius a low compiexiq and can ,jointiy estimate the channel puranieter. Simiilution rr.snlts show that the proposed .scheme shows a yood perJbrmaiice with a low coinpkyiq and can esfimate the channel parameter more correctll: than the conventional scheme. Index Terms -channel estimation, low complexity, MUD, TH-UWB.