適用於無線區域網路與藍芽共存系統中共同偵測器之設計

無線區域網路與藍牙系統為目前兩大無線通訊網路標準。無線區域網路透過存取點(Access Point)連接到有線區域網路進行資料傳輸，具有行動性高、安裝簡便、施工成本低、應用範圍廣等優點；藍牙透過裝置即可建立傳輸通道，容易整合與連結各種通訊、資訊設備進行低成本、低耗電之短距離無線傳輸。兩系統之應用不同，具不可取代性，目前皆被廣泛使用於消費性電子產品中。然而無線區域網路IEEE 802.11g與藍牙同樣使用2.4 GHz的ISM頻帶，當兩系統同一時間將訊號載至相同頻帶時，必然產生互相干擾，造成傳輸錯誤，此即兩系統於ISM頻帶的共存問題。過去的文獻與研究中多以避開兩系統於時域或頻域的同時運作(collision avoidance)來解決，必須犧牲位元傳輸率(throughput)或頻譜效益(spectral efficiency)。為更進一步以不避開碰撞、更主動基本的方式來解決ISM共存問題，本論文提出共同偵測器的想法，透過無線區域網路Wi-Fi與藍牙訊號的同時偵測，降低彼此干擾情況，進而提供更好的無線傳輸品質與服務。共同偵測器應用於無線區域網路基頻接收機內，使用最大似然法則(ML, Maximum Likelihood)演算法，透過已建立的藍牙頻譜資料庫與雜訊特性，全面搜尋所有可能的Wi-Fi與藍牙頻域訊號，一旦搜尋到最有可能的組合，即宣稱找到目前接收的Wi-Fi與藍牙，並將藍牙由接收訊號中扣除以降低干擾。研究最後針對完美通道資訊假設下的模擬環境與實際共存系統中經通道估測的模擬環境做共同偵測器之效能驗證。

關鍵字

無線區域網路； IEEE 802.11g ；藍牙； ISM共存系統；干擾消除；共同偵測器

並列摘要

Currently, wireless local area network (Wireless LAN) and Bluetooth are two important standards in the wireless communication network. They are broadly used and are irreplaceable. However, IEEE 802.11g in Wireless LAN and Bluetooth both utilize 2.4 GHz ISM band. Mutual interference occurs while the two systems modulate signals to the same spectrum at the same time. This is so-called the ISM coexistence issue. The general solution is to avoid simultaneous system operation in the time or frequency domain. By doing this, the throughput and spectral efficiency are sacrificed for the collision avoidance. Therefore, joint detection is proposed as a better solution to jointly detect Wi-Fi and Bluetooth in order to reduce the interference. Maximum likelihood is applied in joint detection to search all possible Wi-Fi and Bluetooth signal through a built-in Bluetooth library. As the most likely Bluetooth is found, it is subtracted from the received signal to reduce the interference. The simulation results under different simulation environments: with perfect channel state information (CSI) knowledge and considering the real coexistence environment are proposed to show the effectiveness of the joint detector dealing with ISM coexistence.

並列關鍵字

Wireless LAN ； IEEE802.11g ； Bluetooth ； ISM Coexistence ； Interference Cancellation ； Joint Detector

參考文獻

[1] IEEE 802.11, IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Nov. 1999.

[5] Francis J. Smith, “Interference Mitigation of Signals Within the Same Frequency Spectrum,” U.S. Patent 2009/0190633, July, 2009.

[6] C. F. Chiasserini and R. R. Rao, “A comparison between collaborative and non-collaborative coexistence mechanisms for interference mitigation in ISM bands,” in Proc. of IEEE Conf. on Vehicular Technology, Rhodes, Greece, May 2001, pp. 2187-2191.

[7] Y.-K. Kwok, and M.C.-H. Chek, “Design and evaluation of coexistence mechanisms for Bluetooth and IEEE 802.11b systems,” in Proc. of the 15th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Barcelona, Spain, Sept. 2004, pp. 1767-1771.

[8] L. Ophir, Y. Bitran, and I. Sherman, “Wi-Fi (IEEE 802.11) and Bluetooth coexistence: issues and solutions,” in Proc. of the 15th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Barcelona, Spain, Sept. 2004, pp. 847-852.

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適用於無線區域網路與藍芽共存系統中共同偵測器之設計

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