지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
논문 기본 정보
- 자료유형
- 학위논문
- 저자정보
- 지도교수
- 안재민
- 발행연도
- 2017
- 저작권
- 충남대학교 논문은 저작권에 의해 보호받습니다.
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이 논문의 연구 히스토리 (2)
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- 연관 학술논문 또는 학술발표를 통해 보다 발전된 연구결과를 확인하실 수 있습니다.
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초록· 키워드
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We studied Narrowband IoT wireless communication system and designed downlink physical layer model of NB-IoT. NB-IoT downlink system organize star network with one base station and many devices. These devices have to synchronize with base station. But they are low-power consumption & low-cost devices, and the system has large frequency offset compared with system bandwidth. In this case, there is considerable discordance of oscillator frequency between transmitter and receiver. So it has a difficulty in signal acquisition.
Therefore, as the solution of this problem, we suggest to apply differential encoding to preamble. Using differential encoding correlation, we can avoid the performance degradation resulted from frequency offset. We verified this process by false alarm/missing probability simulation. And in case of differential encoding correlation, it is more influenced from noise than coherent correlation. Thus, we can increase the SNR by extending the preamble length. Also the preamble has to maximize the SNR and minimize the influence of frequency offset at the same time. So we performed a simulation and selected proper length of preamble.
To conclude, we can overcome the frequency offset by applying differential encoding to preamble. This made signal acquisition and frequency offset estimation possible. After initial frequency offset compensation, we can expect the synchronization performance improvement by frequency and channel tracking using pilot symbols.
Therefore, as the solution of this problem, we suggest to apply differential encoding to preamble. Using differential encoding correlation, we can avoid the performance degradation resulted from frequency offset. We verified this process by false alarm/missing probability simulation. And in case of differential encoding correlation, it is more influenced from noise than coherent correlation. Thus, we can increase the SNR by extending the preamble length. Also the preamble has to maximize the SNR and minimize the influence of frequency offset at the same time. So we performed a simulation and selected proper length of preamble.
To conclude, we can overcome the frequency offset by applying differential encoding to preamble. This made signal acquisition and frequency offset estimation possible. After initial frequency offset compensation, we can expect the synchronization performance improvement by frequency and channel tracking using pilot symbols.
목차
제 1 장 서 론 11.1 연구 대상 및 내용 11.2 논문 구성 2제 2 장 협대역 IoT 시스템의 하향 링크 모델 32.1 전송 채널 모델링 32.2 물리적 채널화 52.3 시간 구조 및 버스트 구조 5제 3 장 하향 링크 프리앰블 설계 103.1 개요 103.2 프리앰블 설계 113.3 프리앰블 획득 알고리즘 203.4 모의실험 결과 및 분석 223.5 결언 27제 4 장 결론 29
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