CAJ | 학술논문

短波通信信道具有频率选择衰落特性,相干带宽是描述单载波系统平坦衰落信道带宽的重要参数.提高相干带宽有利于系统使用更大的带宽来实现高数据速率传输并且有助于减少接收机的复杂度.该文提出一种利用发射端窄波束成形在空间上将发射能量集中于主路径且抑制其它路径信号来提高短波信道相干带宽的方法,并利用自适应技术来建立及保持点对点之间的窄波束通信.理论研究表明,该方法能有效地提高信道相干带宽.该文以中距离短波通信为例,计算了使用不同发射天线数时的相干带宽值,计算结果证实了该方法的有效性.
단파통신신도구유빈솔선택쇠락특성,상간대관시묘술단재파계통평탄쇠락신도대관적중요삼수.제고상간대관유리우계통사용경대적대관래실현고수거속솔전수병차유조우감소접수궤적복잡도.해문제출일충이용발사단착파속성형재공간상장발사능량집중우주로경차억제기타로경신호래제고단파신도상간대관적방법,병이용자괄응기술래건립급보지점대점지간적착파속통신.이론연구표명,해방법능유효지제고신도상간대관.해문이중거리단파통신위례,계산료사용불동발사천선수시적상간대관치,계산결과증실료해방법적유효성.
Shortwave communication works with frequency-selective fading channel, of which coherence bandwidth is an important parameter describing the "flat" channel bandwidth to be used by single carrier system. As has been known, increasing the coherence bandwidth can facilitate larger bandwidth system with faster data rate transmission and simplified system with reduced receiver complexity. This paper proposes a method of using narrow beam to concentrate spatially the transmitted signal power on the main path and suppress the undesired multipath signals resulting in delay spread. For realizing the functions motioned above, the adaptive technique is taken to set up and maintain the narrow beam link for the point-to-point communication. The theoretical study shows that the coherence bandwidth can be effectively increased by this method. The calculations are performed for different number of antennas over the mid-range channel and the results confirm this approach.