• Title/Summary/Keyword: Subchannel grouping

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Dynamic Subchannel Grouping Algorithm using Local Gateways for Enterprise Small-cell Networks

  • Kim, Se-Jin
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.7-13
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    • 2017
  • In this paper, we propose a novel dynamic subchannel grouping (DSG) algorithm to maximize the system capacity considering intended proper outage probability for the downlink of enterprise small-cell networks (ESNs). In the proposed DSG scheme, a local gateway (LGW) which is installed in a building dynamically divides the frequency bandwidth into different numbers of subchannel groups (SGs) based on the numbers of small-cell access points (SAPs) and small-cell user equipments (SUEs) per floor. Then, the LGW assigns the SGs to SAPs and the SAPs allocate them to their serving SUEs. Through simulation results, we show that the proposed DSG scheme is appropriate for the ESNs compared to the conventional small-cell networks in which all SAPs use the number of fixed SGs in terms of the system capacity and outage probability.

Adaptive SFBC-OFDM with Pre-equalizer under Time-varying Multipath Fading Channel (시변 다중 경로 페이딩 환경에서 사전 등화기 기반 적응 변조 SFBC-OFDM 시스템에 관한 연구)

  • 고정선;김낙명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6A
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    • pp.623-630
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    • 2004
  • The adaptive modulation along with SFBC transmit diversity is a very effective method to increase the capacity of an OFDM system. However, severe performance degradation is resulted when inter-symbol interference is applied due to frequency-selective fading in mobile communications. In this paper, we have proposed and analyzed an OFDM system with SFBC transmit diversity and adaptive modulation scheme based on pre-equalization methods, in order to increase the data transmission rate in the downlink without much increase in system complexity. By introducing subchannel grouping and the pre-equalization method among adjacent subchannels, we could enhance the efficiency of the adaptive modulation a lot. By computer simulation, it has been proven that the proposed schemes show a better BER and throughput performance than the conventional schemes under severely time-varying multipath fading channel.