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[Author] Jeongkeun CHOI(2hit)

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  • Performance of a Base Station Feedback-Type Adaptive Array Antenna with Limited Number of Feedback Bits

    Jeongkeun CHOI  Yoshihiko AKAIWA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E89-B No:6
      Page(s):
    1793-1798

    Feedback-type Adaptive Array Antenna has been proposed for frequency division duplexed (FDD) system, where the mobile station (MS) measures channel characteristics and sends those back to the base station (BS). Using a higher number of feed-back bits provides better performance. However it wastes channel capacity of the up-link. On the other hand, error in feedback signals transmission causes significant performance degradation. To solve these problems, this paper proposes a method that the MS sends back the difference between the optimum weights calculated at the MS and weights which are currently used at the BS. Bit error rate performance of the system is shown under a realistic propagation condition.

  • Performance of a Base Station Feedback-Type Adaptive Array Antenna with Mobile Station Diversity Reception

    Jeongkeun CHOI  Yoshihiko AKAIWA  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E88-B No:5
      Page(s):
    2081-2086

    In the cellular mobile communication systems, co-channel interference and Rayleigh fading degrade the transmission performance. Adaptive Array Antenna (AAA) can suppress interference and, at the same time, can cope with multi-path fading by using a wide antenna spacing resulting in low correlation of received signals in each antenna element. A feedback-type AAA was proposed for frequency division duplexed (FDD) systems, where mobile station measures channel characteristics and feed-backs them to the base station. In this paper, we extend the system by introducing 2-branch diversity reception at a mobile station, and study the influence of antenna element spacing at the base station and control delay time on bit error rate performance under a realistic propagation model.