Experimental Evaluation of a Scalable WiFi Multicast Scheme in the ORBIT Testbed

IEEE 802.11-based wireless local area networks, referred to as WiFi, have been globally deployed and the vast majority of the mobile devices are currently WiFi-enabled. While WiFi has been proposed for multimedia content distribution, its lack of adequate support for multicast services hinders its ability to provide multimedia content distribution to a large number of devices. In earlier work, we proposed a dynamic scheme called AMuSe that selects a subset of the multicast receivers as feedback nodes. The feedback nodes periodically send information about channel quality to the multicast sender and the sender in turn can optimize multicast service quality, e.g., by dynamically adjusting transmission bit-rate. In this paper, we discuss several experimental results for the performance evaluation of AMuSe. Our experiments use more than 250 nodes placed in a grid topology in the ORBIT testbed. We consider different experimental scenarios: with and without the presence of external noise. Our focus is on studying the performance of WiFi nodes in WiFi multicast and establishing the conditions that make AMuSe an attractive scheme for feedback in WiFi multicast.