volve to FuTURE TDD. FuTURE TDD has much in common with LTE TDD. Hence, the two systems may exist at the same time. With the development of software-defined radio and the commonality of the systems, it is easy for operators to change between FuTURE TDD and LTE TDD. On the other hand, FuTURE TDD adopts many more advanced techniques, such as GDAA and virtual MIMO. Hence, it can bring many good points, which are the characteristics of 4G, named IMT Advanced. Hence, the evolution from LTE TDD to FuTURE TDD is also necessary. Bibliography Adel, A. M., A. J. Saleh, J. R. Rustakl, and R. S. Roman. 1987. Distributed antennas for indoor radio communications, IEEE Transactions on Communications 35 (12). Bell Laboratories. 1971. High-capacity mobile telephone system technical report, December. Erdal, C. and C. Ersoy. 2002. Application of 3G PCS technologies to rapidly deployable mobile networks. IEEE Network 16 (5): 20-27. Foschini, G. J. 1996. Layered space-time architecture for wireless communication in a fad- ing environment when using multielement antennas. Bell Labs Technical Journal 41-59. Foschini, G. J. and M. J. Gans. 1998. On limits of wireless communications in a fading environment when using multiple antennas. Wireless Personal Communication 311-335. Frattasi, S., H. Fathi, F. H. P. Fitzek, R. Prasad, and M. D. Katz. Defining 4G technology from the user's perspective. IEEE Network 20 (1). Gao, Xiqi, Shidong Zhou, and Wuyang Zhou. 2007. FuTURE FDD system: Key technolo- gies and experimental validation. FuTURE Forum 2 (1): 50-53. Ghosh, A., D. R. Wolter, J. G. Andrews, and R. Chen. 2005. Broadband wireless access with WiMax/802.16: Current performance benchmarks and future potential. IEEE Communications Magazine Feb. Guangyi, Liu, Jianhua Zhang, Ping Zhang, Ying Wang, Xiantao Liu, and Shuang Li. 2006. Evolution map from TD-SCDMA to FuTURE B3G TDD. IEEE Communications Magazine March: 54-61. IEEE 802.16. http://groups.ieee.org/group/802/16/ ITU. 2007. Circular letter for IMT Advanced. Klein, S. G. 1991. On the capac