Load Balance for IEEE 802.11 Wireless LAN with Bluetooth Low Energy

在使用者較為密集的場合中，常會碰到無線網路壅塞的問題，例如在一個大型會議廳中，常會在各個IEEE 802.11頻道上部署不同的WiFi AP（Access Point），來分散使用者的連線。但是由於IEEE 802.11的連線機制是屬於使用者主導（client driven），只能透過使用者去選定AP進行連線，對於使用者裝置來說,，連線到不同AP的優先順序，是依照接收到不同AP的信號強度（RSSI）作為排序指標。這種做法會讓在空間上使用者分佈不平均的環境中，造成多數使用者UE只連線到少數AP，而其餘AP資源閒置無用的情形。 本論文提出一個IEEE 802.11的負載平衡解決方案，結合藍牙低功耗（Bluetooth Low Energy，BLE）及IEEE 802.11成為一個智慧型AP架構。我們利用藍牙低功耗通訊協定GATT （Generic Attribute Profile）分派AP給不同使用者進行連線，再結合馬可夫鏈平穩狀態分佈（Markov Chains Stationary Distribution）演算法，依照使用者在AP網路拓樸中的歷史分佈紀錄，將多個AP的分派轉化為Erlang-C模型的排隊系統以計算AP分派規則，藉此達到系統的負載平衡。Usually, a user crowded space encounters wireless network congestion problem. For example, a large conference hall often deploys different wireless AP (Access Point) on each IEEE 802.11 channel to separate users’ connections. However, since the connection mechanism of IEEE 802.11 is client driven, the AP connection is selected by the user and the selection is according to the received signal strength (RSSI) from different APs. This conventional approach may result in most of the user devices connect to relatively limited number of APs, and the resource of the rest of the APs left unused. This paper proposes a smart AP architecture which is able to manage load balance for IEEE 802.11 Wireless LAN using Bluetooth Low Energy (BLE) GATT (Generic Attribute Profile) protocol in order to appropriately assign AP to different user devices. The core AP assignment algorithm is based on Markov chain stationary distribution. Simulation results show that the proposed BM-MS (BLE Management with Markov-Chains Stationary Load Balance) method outperforms RSSI based method in terms of system throughput and average user data rate