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Underwater Acoustic OFDM-Based Signal Detection
|Contributors: ||NTOU:Department of Electrical Engineering|
|Issue Date: ||2011-06-28T08:08:49Z
|Abstract: ||摘要:近十年來，水下感測網路的研究是重點項目，其應用範圍包括海洋環境資料收集、海岸資源探勘、污染監控及軍事監測等。在水下感測網路中，監測點的儀器、自主水下載具及海上工作站均配置聲訊收發器，可以彼此通訊。源自於水下通道的主要障礙包括延遲高、可用頻寬窄、都卜勒與時間延遲擴展大及多路徑衰弱嚴重。這些因素會使資料傳輸量受到限制及使通訊可靠度變差。因此需要先進的訊號處理技術來克服這些不利的通道因素。 由於多輸入多輸出(MIMO)的空時編碼(Space-Time Coding)技術可以增加系統容量及正交分頻多工(OFDM)的多載波調變可以大幅降低接收器的複雜度，因此過去十年來有關OFDM-MIMO之信號偵測研究不少。然而這些方法僅侷限於單一使用者，當使用者數目增加時，其偵測效能大幅降低。 因此，本計畫的目標在於從事利用正交分頻多工(OFDM)多載波調變、分碼多工(CDMA)、多輸入多輸出(MIMO) 的空時編碼技術之多使用者訊號偵測技術的研究，使其能適用於水下通訊。本計畫為三年期計畫。第一年為進行系統理論模式建立及電腦模擬驗證。第二年集中於效能改善之訊號偵測技術的研究。第三年為整合各子計畫的程式模組進行基隆碧沙漁港淺海域的水下通訊實驗|
abstract:In the past decade, there has been a research trend geared toward the development of underwater sensor networks for applications such as environmental data collection, offshore exploration, pollution monitoring, military surveillance. In underwater sensor networks, sensor nodes, autonomous underwater vehicles (AUVs) and surface stations are equipped with acoustic modems to communicate with each other. Major obstacles posed by an underwater acoustic channel are high latency, small available bandwidth, large Doppler and delay spreads, severe multipath fading. These factors limit data throughput and degrades reliability. Thus, advanced communication techniques are needed to combat these channel impairments. Because multiple- input multiple-output (MIMO) channel scheme via space-time coding (STBC) can increase system capacity, and multicarrier modulation of orthogonal frequency division multiplexing (OFDM) can significantly reduce the receiver complexity, signal detection based on the OFDM-MIMO scheme has been actively investigated in the past ten years. However, the performances of these detection schemes, only valid in single-user scenarios, severely degrade as the number of users increases. For these reasons, the research goal of the subproject is to investigate multiuser detection methods based on the signaling scheme of OFDM-CDMA and a space-time coding (STBC) for MIMO channel, for underwater acoustic communications. The project needs to be completed within three years. In the first year, the project is responsible for performing theoretical formulation and functional validation via computer simulations. In the second year, we’ll focus on developing detection techniques that can lead to performance improvement. In the third year, the detection software module will be integrated with software modules contributed by four other sub-projects to perform sea trials in the shallow water region of the Bi-Sa fishery harbor located in Keelung.
|Appears in Collections:||[電機工程學系] 研究計畫|
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