＜正＞Dear editor,To compensate for a coverage gap in mmW ave communication systems [1], a directional cell search （CS） scheme based on beam scanning was proposed [2–5]. Directional beamforming using a narrow beam （NB） can improve the coverage by considering a high beam gain; however, it will introduce a significant CS delay （CSD） if the beamwidth is too narrow as the beams have to se-
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