m resource more sufficiently and enable the cell-edge users to obtain better performance, SFFR is proposed for OFDMA-based systems. Based on SFFR, the basis of mitigating intercell interference through resource planning/ coordination is to classify the users into cell-edge users and inner-cell users accord- ing to their geometry factor. The threshold of the geometry factor can be deter- mined by actual traffic distribution in one certain cell. Considering the following rules, users in each cell are divided into two major groups. One group is for cell-edge users, and the other group is for inner-cell users. Assign the whole frequency band for all users in each cell as follows: Split the whole frequency band into two parts, G and F. According to SFFR, frequency is assigned as follows: Frequency set G and a subset of F are available for inner-cell users; for cell-edge users, SFFR strategy is illustrated by Figure 2.10. Frequency reuse is a basic technology in wireless systems. In this proposal, SFFR strategy is proposed for intercell interference mitigation based on extension set the- ory. SFFR can improve spectral efficiency and improve performance of cell-edge users. It can also be used to accomplish the frequency plan for the whole network. Denotes ul Cell 3 Denotes u2 Cell 2 Denotes u3 Denotes u4 Cell 1 Denotes u5 @@@@@@@@@@ Figure 2.10 SFFR scheme for three-cell model. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology 2.2.3 FuTURE TDD Trial System and Trial Network 2.2.3.1 Hardware Implementation for FuTURE TDD Trial System Based on the research of basic theories for the FuTURE TDD system, the hardware demonstration system has been developed and field tested in multicell networks. This hardware platform supports the peak data rate of more than 100 Mb/s and can meet users' requirements for various future services with different QoS, including HDTV, VoIP, data, video, FTP, and Internet. The FuTURE TDD system adopts an overall infrastructure of the general hardware p