Layered OFDMA and Its Radio Access Techniques for LTE-Advanced

Abstract

This paper proposes applying the Layered Orthogonal Frequency Division Multiple Access (OFDMA) radio access scheme and its radio access techniques to LTE (Long-Term Evolution)-Advanced to satisfy its system requirements, which are much stricter than those of the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN). Layered OFDMA comprises layered transmission bandwidth assignment (bandwidth is assigned to match the required data rate), a layered control signaling structure, and support for layered environments for both the downlink and uplink. Especially in the uplink, an adaptive multi-access scheme with hybrid single-carrier and multicarrier based radio access is applied. Layered OFDMA radio access will support all the functionalities specified in Release 8 LTE and later enhancements. Key radio access techniques such as fast inter-cell radio resource management that takes advantage of remote radio equipment (RRE) so as to realize inter-cell orthogonality, multi-antenna transmission with more antennas, and coverage enhancing techniques are used to achieve a high level of capacity and cell-edge spectrum efficiency.