近年來物聯網在農業上由於LPWAN（Low-Power Wide-Area Network，低功率廣域網路）的逐漸成熟，其低功耗、長距離傳輸的性質正符合了農地大範圍傳輸區域、長期偵測的需求。許多應用包含環境偵測、智慧灑水、蟲害監測得以藉此實踐。
   本論文以建置農地物聯網監控為實際案例，使用兩個單通道LoRa傳輸晶片來實現一個多通道LoRa Gateway，滿足農地uplink與downlink的傳輸需求，同時降低了建置LoRa Gateway的基本設備需求。
   本論文在案例中，於建置農地監控中，針對環境感測節點，由於節點設定功率時需一一設定，提出節點功率自動調整的解決方案;節點備份資料缺乏資料取得時間，與gateway取得時間戳記；針對水閥控制缺少狀態回報提出指令重傳機制、狀態回報。

In recent years, due to the maturity of LPWAN (low-power wide-area network) in the Internet of Things, its low-power and long-distance transmission are in line with the large-scale transmission area of agricultural land and the need for long-term detection.    
This paper purpose that using two single-channel LoRa transmission chips to simulate a multi-channel LoRa Gateway transmits with agricultural IoT monitoring.
It's not only meets the transmission requirements of agricultural land uplink and downlink also reduces the construction of LoRa Gateway’s basic equipment requirements.
In this paper, in the construction of agricultural land monitoring, due to the environment sensor node setting, the node needs to be confirmed the power one by one, a solution of sensor node power automatic adjustment is proposed; the sensor node backup data without the timestamp, and we purpose a method which query the gateway to get the timestamp; The water valve control has no the state reporting, we design a mechanism which can retransmit the message and report the status of water valve to user.

第一章 緒論 .............................................. 1
1.1 研究背景 ......................................... 1
1.2 研究目的 ......................................... 4
1.3 論文架構 ......................................... 5
第二章 相關研究 .......................................... 6
2.1 無線傳輸技術 ..................................... 6
2.1.1 LoRa 無線傳輸 ................................ 7
2.1.2 Sigfox ....................................... 8
2.1.3 NB-IoT ....................................... 9
2.2 單通道晶片Gateway 建置案例 ...................... 10
第三章 系統架構與實現 ................................... 11
3.1 系統架構 ........................................ 12
3.2 系統層面 ........................................ 13
3.3 LoRa Gateway 傳輸系統設計 ....................... 14
3.3.1 LoRa Gateway 傳輸架構 ....................... 14
3.3.2 Uplink、downlink 傳輸運作流程 ............... 16
3.3.3 封包格式 .................................... 18
3.4 節點傳輸功率調整流程 ............................ 19
3.5 節點詢問時間戳記流程 ............................ 25
3.6 環境偵測節點傳輸運作流程 ........................ 27
3.7 水閥控制狀態追蹤流程 ............................ 28
第四章 系統驗證 ......................................... 31
4.1 LoRa Gateway 傳輸系統驗證 ....................... 32
4.2 節點傳輸功率調整流程驗證 ........................ 40
4.3 節點詢問時間戳記流程驗證 ........................ 41
4.4 水閥控制狀態追蹤流程驗證 ........................ 42
第五章 結論與未來展望 ................................... 43
5.1 結論 ............................................ 43
5.2 未來展望 ........................................ 44
參考文獻 ................................................ 45
附錄一 英文論文 ......................................... 46

圖目錄
圖 1 系統架構圖 ......................................... 12
圖 2 系統層面圖 ......................................... 13
圖 3 Gateway 傳輸架構 .................................... 14
圖 4 Uplink、downlink 頻率設定 ............................ 15
圖 5 Uplink 運作流程 ..................................... 16
圖 6 Downlink 運作流程 ................................... 17
圖 7 封包格式 ........................................... 18
圖 8 節點傳輸功率調整流程1 ............................. 19
圖 9 自動功率調整階段分層 ............................... 19
圖 10 自動功率調整第二階段 .............................. 20
圖 11 自動功率調整第三階段 .............................. 21
圖 12 二分法pseudocode .................................. 22
圖 13 二分法示意圖 ...................................... 22
圖 14 傳輸測試成功 ...................................... 23
圖 15 傳輸測試失敗 ...................................... 23
圖 16 節點傳輸功率調整流程2 ............................ 24
圖 17 資料備份狀況 ...................................... 25
圖 18 節點詢問時間戳記 .................................. 26
圖 19 節點詢問時間戳記2 ................................ 26
圖 20 改善後uplink 傳輸流程 .............................. 27
圖 21 傳統水閥傳輸 ...................................... 28
圖 22 水閥控制狀態追蹤流程 .............................. 28
圖 23 Downlink 回報問題 .................................. 29
圖 24 改善後downlink 傳輸流程 ........................... 29
圖 25 水閥傳輸成功情形 .................................. 30
圖 26 水閥傳輸失敗情形 .................................. 30
圖 27 農地傳輸場域範圍 .................................. 31
圖 28 Uplink 傳輸 ........................................ 32
圖 29 LoRa Gateway 接收情形 ............................. 33
圖 30 Uplink MQTT 傳輸 .................................. 33
圖 31 資料庫數據 ........................................ 34
圖 32 Downlink 傳輸 ...................................... 35
圖 33 使用者發出指令 .................................... 35
圖 34 Arduino-downlink 傳輸 ............................... 36
圖 35 Arduino-downlink 傳輸 ............................... 37
圖 36 Downlink & uplink ................................... 38
圖 37 Uplink、downlink 同時運作情形1 ..................... 38
圖 38 Uplink、downlink 同時運作情形2 ..................... 39
圖 39 Arduino-節點傳輸功率調整 ........................... 40
圖 40 備份資料時間戳記 .................................. 41
圖 41 水閥即時狀態及資料庫情形 .......................... 42
圖 42 水閥異常提醒 ...................................... 42

表目錄
表 1 無線傳輸比較 ........................................ 1
表 2 雙單通道性質比較 .................................... 2
表 3 SX1301 與SX1276 成本比較(2018) ...................... 3

[1] K. Mekki, E. Bajic, F. Chaxel, F. Meyer, “A comparative study of LPWAN technologies for large-scale IoT deployment”, ICT Express, 2018.
[2] C. Pham, A. Rahim, P. Cousin, “Low-cost, long-range open iot for smarter rural african villages”, In 2018 IEEE International Smart Cities Conference (ISC2), pp. 1–6, 2016.
[3] W. Zhai,“Design of NarrowBand-IoT Oriented Wireless Sensor Network in Urban Smart Parking”, In 2017 International Journal of Online Engineering (iJOE), Vol 13, No 12 , pp. 116-126 , 2017.
[4] D. H. Kim, J. Y. Lim, J. D. Kim, “Low-power, long-range, high-data transmission using Wi-Fi and LoRa”, In 2016 6th International Conference on IT Convergence and Security (ICITCS), pp. 1–3, 2016.
[5] V. Gokul and S. Tadepalli, “Implementation of a wifi based plug and sense device for dedicated air pollution monitoring using IoT”, In 2016 Online International Conference on Green Engineering and Technologies (IC-GET), pp. 1–7, 2016.
[6] M. Lauridsen ,B. Vejlgaard ,I. Z. Kovacs, H. Nguyen ,P. Mogensen,
“interference Measurements in the European 868 MHz ISM Band with Focus on LoRa and SigFox”, In 2017 IEEE Wireless Communications and Networking Conference (WCNC), pp. 1-6, 2017.
[7] K. E. Nolan, W. Guibene, M. Y. Kelly, “An evaluation of low power wide area network technologies for the Internet of Things” ,In 2017 nternational Wireless Communications and Mobile Computing Conference (IWCMC), pp. 439–444, 2016. 
[8] R. Ratasuk, B. Vejlgaard, N. Mangalvedhe, A. Ghosh, “NB-IoT system for M2M communication”,In 2016 EEE Wireless Communications and Networking Conference Workshops (WCNCW), pp. 428–432, 2016.