使用霍爾效應之磁感應通訊系統

Abstract

由於其在嚴厲環境中所表現出的優良穩定性，近場磁感應通訊系統的研究在近年來漸漸受到注目。多項研究顯示近場磁感應通訊系統在非空氣的空間中有較好的應對能力，而這是由於磁場在各種不同的介質當中，所表現出來的傳輸特性相似度極高。在本論文中，我們實作出了第一個結合霍爾效應磁感應器的近場磁感應通訊系統。我們利用了此類感應器之體積小、高精度、高反應速度之特性。同時，為了提高整體系統的傳輸速度，我們在系統的設計中加上了多重輸入多重輸出(MIMO) 的技術。此設計同時也使得系統獲得更高的靈活度，得以在不同的使用情境下改變其傳輸速度及系統體積。另外，我們提出了一種校正方法，來面對磁力強度的非線性特性。實驗結果顯示在目前的系統可以達到每秒44 位元組的傳輸速度，同時只有1.73% 的位元錯誤率。最後，我們透過實驗分析出，當能夠做硬體突破並改善線圈製程的情況下，此系統有達到每秒傳輸1700 位元組的潛力。

Due to its reliability in the harsh environments, Near Field Magnetic Induction Communication (NFMIC) starts to gain attention in recent years. Several studies show that NFMIC has the ability to cope with non-air space because of its channel characteristic in such mediums. In this thesis, we implement the very first NFMIC system that utilizes the Hall sensors by taking advantages of its feature such as small volume, high sensitivity and high operation frequency. To boost the throughput of the system, we implement a Multiple Input Multiple Output (MIMO) scheme. This also provides flexibility in scaling the system into different sizes in order to satisfy the needs of various applications. Furthermore, we propose a mid-point calibration method to deal with the nonlinearity of the magnetic receiver. The evaluation results show that the system can reach a throughput of 44 bytes per second with only 1.73% bit error rate. Finally, we estimate that if it is possible to address the issues of the hardware limitations and assemble a system with a large number of transmitting coils in a small area, the system throughput would be able to improve to 1700 bytes per second.