Layered OFDMA Radio Access for IMT-Advanced

This paper proposes layered orthogonal frequency division multiple access (OFDMA) radio access for LTE (long-term evolution)-advanced to achieve higher-level system requirements than those in Release 8 LTE called Evolved UMTS terrestrial radio access (UTRA) and UMTS terrestrial radio access network (UTRAN). Layered OFDMA comprises layered transmission bandwidth assignment according to the required data rate, a layered control signaling structure, and support for layered environments in which an adaptive multi-access scheme with hybrid single-carrier and multicarrier based radio access is applied. layered OFDMA radio access will support all functionalities provided in Release 8 LTE and its enhancement. Key radio access techniques such as fast inter-cell radio resource management that take advantage of remote radio equipment (RRE) aiming at inter-cell orthogonality, multi-antenna transmissions with more antennas, and coverage enhancing techniques are used to achieve a high level of capacity and cell-edge spectrum efficiency.