Bong Youl Cho

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—We propose an Automatic On–Off Switching (AOS) re-peater that is switched off automatically when there is no active user within its coverage. With the AOS repeater, we can reduce the unnecessary noise enhancement. The reverse link capacity of a DS/CDMA system with AOS repeaters is analyzed mathematically and compared with that of a system with conventional(More)
In mobile communication systems, there are areas where signal coverage is not adequately accomplished by base stations. These areas may be underground parking zones, underground stores, tunnels, and insides of buildings, etc. In these areas, repeaters are broadly used as an economical solution. However, the capacity is decreased as the number of repeaters(More)
SUMMARY In this paper, the improvement technique for a nonlinear parallel interference cancellation (PIC) receiver for a DS-CDMA system is studied, which cancels only the estimated multiple access interference (MAI) from specific users at each receiver stage. This technique was introduced as a PIC receiver using null zone hard decision in ØØØ ÔÖÓÒÒ ÓÓ ÁÁÁÁ(More)
To overcome a multipath fading environment with low complexity and to achieve wireless broadband multimedia communication systems, orthogonal frequency division multiplexing (OFDM) transmission scheme is used. OFDM is one of the applications of a parallel data transmission scheme, which reduces the influence of multipath fading. The performance of OFDM can(More)
Multiple input multiple output (MIMO) has been considered as one of the key enablers of the broadband wireless communications. In this paper, we describe the several practical deployment cases where repeater links (or relay links) such as distributed antenna system (DAS) can act as keyholes to degenerate the rank property of MIMO communications. In order to(More)
In this paper, we propose and analyze an turbo coding scheme for optical CDMA systems. It is assumed that optical channel is an intensity modulated(IM) channel and direct-detection scheme is employed to deted the received optical signal. From simulation results, it is demonstrated that bit error probability (BEP) and throughput performance is substantially(More)
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