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    Item type:Publication,
    Performance analysis of space diversity for OFDM transmission
    (2008-12-01)
    Lorphichian, Aekkarat
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    Nakasuwan, Jintana
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    Srikalsin, Thanupong
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    Benjangkaprasert, Chawalit
    This paper presents a simple space diversity scheme for orthogonal frequency-division multiplexing (OFDM) transmission. Using multiple antenna technology provides the same diversity order as maximal-ratio receiver combining (MRRC). It is also shown that the scheme may easily be generalized to M transmit antennas and M receive antennas to provide a diversity order of 2M. We examine feasibility of several types of OFDM transmitter diversity techniques and generate data for the third-generation wireless systems. In particular, single input single output (SISO), single input multiple output (SIMO), multiple input single output (MISO), and multiple input multiple output (MIMO) techniques are compared. We employ the long range AWGN channel to enable transmitter diversity.
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    Item type:Publication,
    Performance analysis of channel effective for wireless LAN and wireless ad-hoc networks
    (2008-12-01) ;
    Nakasuwan, Jintana
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    Lorphichian, Aekkarat
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    Benjangkaprasert, Chawalit
    Wireless local area networks (WLANs) provide mobility and convenience to users, the efficiency of today's WLANs are still far from satisfactory. In this paper discusses the performance of WLANs and wireless Ad-Hoc networks, our main contribution is analyze several methods to compare the throughput performance on simulation and experimental results. We describe NS-2 (Network Simulation) implementations for fine-tuning WLAN and wireless Ad-Hoc network parameters such as the physical layer (IEEE802.ll) datalink layer (MAC) and network layer (Routing Protocol) related parameters. Customizing these parameters oppose to using the values specified in the standards will increase throughput and channel utilization under fixed load conditions.
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    Item type:Publication,
    The design of linear and circular polarization for dual band microstrip slot antenna
    (2014-01-01) ;
    Rakluea, Paitoon
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    Anantrasirichai, Noppin
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    Benjangkaprasert, Chawalit
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    Wakabayashi, Toshio
    This paper presents a lightweight antenna for wireless communication systems. The proposed antenna has been designed to be a dual-band and dual-polarized antenna by using a right-angled slot structure fed a by microstrip line. The designed antenna is composed of three right-angled slot radiators on the ground plane. The first two radiators are right-angled slots of similar scale which are added to generate circular polarization at 4.95 GHz, while the last one has been designed for linear polarization at 2.45 GHz. Furthermore, in order to achieve dual-band operation and dual polarization with good matching, a special arrangement is proposed. The results of simulation and measurements such as return loss, axial ratio, and radiation patterns are shown at the resonant frequencies of 2.45 and 4.95 GHz. Details of the experimental results are presented and discussed. In addition, the presented antenna can operate and cover the applications of a wireless local area network (WLAN IEEE 802.11 a/b/g/j/n). © 2014 Institute of Electrical Engineers of Japan.