Towards 5G

11Advanced Multiple-access and MIMO Techniques

NOMA sections: Anass Benjebbour,¹ Anxin Li,² Kazuaki Takeda,¹ Yoshihisa Kishiyama,¹ and Takehiro Nakamura¹

SV-MIMO sections: Yuki Inoue,¹ Yoshihisa Kishiyama,¹ and Takehiro Nakamura¹

¹ NTT DoCoMo Inc., Tokyo, Japan

² DoCoMo Beijing Communications Laboratories Co., Ltd, Beijing, China

11.1 Introduction

In cellular mobile communications systems, the design of the radio access technology (RAT) is one important aspect of improving system performance – spectrum utilization efficiency, system capacity, user fairness – in a cost-effective manner. Radio access technologies are typically characterized by the multiple-access scheme used: frequency division multiple access (FDMA), time division multiple access, code division multiple access, orthogonal frequency division multiple access (OFDMA), and spatial division multiple access (SDMA). These schemes provide the means for multiple users to access and share the system resources simultaneously. In the 3.9th and 4th generation (4G) mobile communications systems such as Long-Term Evolution (LTE) and LTE-Advanced [1–3], standardized by the 3rd Generation Partnership Project (3GPP), orthogonal multiple access (OMA) based on OFDMA or single carrier (SC)-FDMA was adopted. On the other hand, SDMA and multiple-input multiple-output (MIMO) are also enabled as key technologies in order to improve the spectrum efficiency of LTE/LTE-Advanced. For example, new transmission modes for single-user MIMO ...