Virtual Direct Link Access for IEEE 802.16 Wireless Metropolitan Area Networks (WMANs). - Hua-Chiang Yin; Yih-Guang Jan; Shiann-Tsong Sheu; Heng-Iang Hsu; Yi-Hsueh Tsai; Chih-Chiang Hsieh; Tien-Hsiang Lo; Frank Chee-Da Tsai (VTC Spring, 2007)