A Cooperative Clustering Protocol for Energy Saving of Mobile Devices with WLAN and Bluetooth Interfaces

One of the most widely used wireless communication standards is a Wireless Local Area Network (WLAN) (IEEE 802.11). However, WLAN has a serious power consumption problem. In this paper, we propose a novel energy saving approach that exploits the multiradio feature of recent mobile devices equipped with WLAN and Bluetooth interfaces. Unlike previous approaches, our work is based on clustering. In our work, a cluster is a Bluetooth Personal Area Network (PAN), which consists of one cluster head and several regular nodes. The cluster head acts as a gateway between the PAN and the WLAN, enabling the regular nodes to access the WLAN infrastructure via low-power Bluetooth. We present a distributed clustering protocol, Cooperative Networking protocol (CONET), which dynamically reforms clusters according to each node's bandwidth requirement, energy use, and application type. CONET does not require modifications of existing wireless infrastructures because clustering is performed independently of WLAN access points. We implemented the CONET prototype with four wearable computing devices to evaluate the performance on real hardware. We also simulated CONET for large networks of more than 100 mobile nodes. Both results demonstrate that our approach is effective in reducing the power consumption of WLAN.