Bong Youl Cho

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We propose an Automatic On–Off Switching (AOS) repeater 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)
'94 , but the numerical results has not been fully provided with varying decision threshold. In this paper, the performance of the PIC receiver using null zone hard decision is shown in a Rayleigh fading channel. Also, a new PIC receiver with an adaptive decision threshold is proposed. In the proposed new PIC receiver, the decision threshold for partial(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)
High-performance 4th generation (4G) broadband wireless communication system can be enabled by the use of multiple antennas not only at transmitter but also at receiver ends. A multiple input multiple output (MIMO) system provides multiple independent transmission channels, thus, under certain conditions, leading to a channel capacity that increases(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)
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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