- 學位論文
以非協調性機制解決藍芽傳輸遭受無線區域網路干擾的問題
Solving the Interference Problem due to Wireless LAN for Bluetooth Transmission Using a Non-Collaborative Mechanism
摘要
藍芽(Bluetooth)為近幾年來新興的短距離無線傳輸技術，其低功率以及便利性使令人矚目。它和無線區域網路WLAN (Wireless Local Area Network, IEEE802.11b) 各有不同的應用以及優點，故皆成為當今短距離無線通訊網路的主要標準。 很不幸的，藍芽及WLAN的頻帶都是在2.4 GHz的ISM (Industrial, Scientific, Medical)公用頻帶上，因此衍生出相互干擾的問題。本論文探討以非協調性機制來解決WLAN對藍芽干擾的問題，所討論的機制包括自適性調節封包大小、自適性跳頻、以及頻率零化(Nulling)，其中頻率零化原本被用來解決藍芽對WLAN干擾的影響，本論文則探討此機制在解決WLAN對藍芽干擾問題的效能。最後對三種機制的效能作分析及比較。 實驗結果顯示，使用自適性調節封包大小以及頻率零化的方式可以使WLAN干擾下的藍芽系統流量獲得大幅的提昇，其中頻率零化的方式在藍芽受到較大干擾時會有比較大的流量增益。另外將自適性跳頻的方式運用在藍芽語音的封包傳輸上，可以使藍芽語音封包的傳輸完全不會受到WLAN的封包碰撞。 總之，在未違反FCC的跳頻法規(Rule 15.247)之下，使用非協調性機制中的方法的確可以解決上述的干擾的問題。此外，文中所提出的頻率零化機制更可以降低使用自適性調整封包大小機制在受到較大的WLAN干擾時小封包重傳率。
並列摘要
Bluetooth is a recently developed wireless transmission technology. It attracts great attention due to its low power and convenience. Bluetooth and WLAN (Wireless Local Area Network, IEEE802.11b) have different applications and advantages. Thus, they both become main standards for short-range wireless communications network. Unfortunately, Bluetooth and WLAN share the same 2.4 GHz ISM (Industrial, Scientific, Medical) band, resulting in an interference problem between them. In this thesis, we study the non-collaborative solutions for Bluetooth under the interference of WLAN, including adaptive packet size, adaptive hopping and nulling. The nulling mechanism was used to solve the interference effect of Bluetooth on WLAN. However, in this thesis, the nulling mechanism is proposed to solve the Bluetooth transmission problem under WLAN interference. Finally, we evaluate and compare the performance of these three mechanisms. In the experimental results, the Bluetooth throughput under the interference of WLAN is improved substantially using the mechanism of adaptive packet size. Furthermore, better throughput gain is obtained using the nulling mechanism when Bluetooth suffers from larger interference. Finally, when the adaptive hopping mechanism is used in audio packet transmission of Bluetooth, Bluetooth packets can avoid the collision of WLAN packets completely. In conclusion, a non-collaborative mechanism can indeed be used to solve the interference problem mentioned above without violating the frequency-hopping rule (Rule 15.247) of FCC. Furthermore, the proposed nulling mechanism can reduce the retransmission rate of small packets when the adaptive packet size mechanism is used in larger WLAN interference.