[IEEE 2007 3rd International Conference on Testbeds and Research Infrastructure for the Development of Networks and Communities - Lake Buena Vista, FL, USA (2007.05.21-2007.05.23)] 2007 3rd International Conference on Testbeds and Research Infrastructure for the Development of Networks and Communities - Integrating multiuser dynamic OFDMA into IEEE 802.11a and prototyping it on a real-time software-defined radio testbed