l process is done in the signal processing unit. AP also contains the cell-specific radio resource management. This enables the AP to manage its radio resources autonomously. On demand, they are requested from the RAN server via the Iu_c* interface. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology 2.2.2.2 Physical Layer Techniques To obtain the peak data rate of more than 100 Mb/s, the FuTURE TDD system adopts many key technologies in the physical layer, such as OFDM, MIMO, PAPR (peak-to-average power ratio) reduction, and link adaptation. To realize the trans- mission data rate up to 1 Gb/s, deep studies have been carried out on the physical layer technologies by introducing some basic theories, such as information theory, norm theory, and matrix theory. In the FuTURE TDD system, the technologies of OFDM combined with MIMO are used to utilize the characters of OFDM fully under the MIMO struc- ture. The OFDM technology has better capability of anti-multipath interference and higher spectrum efficiency than nonorthogonal multicarrier solutions. Moreover, it can be realized by simple discrete Fourier transform (DFT), SO it will be an impor- tant technology in the next mobile communication system. Meanwhile, the system adopts the turbo code with bit rate of 100 Mb/s coupled with puncturing and soft demodulation technologies to enhance the system performance and decrease the transmission power; it realizes wideband wireless access with low power con- sumption and high peak data rate. Additionally, in order to utilize fully the spa- tial resource to transmit data, the MIMO detection technology, which has good performance, is used at the receiver. Four antennas in the MT and eight in the AP form a 4 X 8 MIMO system. At the same time, the technology of V-BLAST (vertical Bell Laboratory layered space-time) codes, combined with interference cancellation, is adopted. The technologies mentioned earlier increase spectrum effi- ciency and improve system performance because of t