This paper investigates the resource allocation (RA) problem for the downlink multiple input multiple output-based non-orthogonal multiple access (MIMO-NOMA) system, which is usually solved through a beamforming (BF) process and a user selection (US) process. In this paper, we propose the multiple-user channel state information (CSI)-based singular value decomposition (MU-CSI-SVD) BF scheme and the minimization of power (Min-Power) US scheme. Under perfect CSI scenarios, the proposed MU-CSI-SVD achieves near optimal sum rate performance with the high-complexity BF scheme while has the same level computational complexity as the low-complexity BF scheme. For imperfect CSI scenarios, the proposed MU-CSI-SVD also achieves better outage probability performance but requires the same level computational complexity as the existing low-complexity BF scheme. Moreover, MU-CSI-SVD is helpful to decrease the computational complexity for solving the Min-Power US problem. Compared with existing US schemes, the proposed Min-Power scheme can achieve larger sum rate or lower outage probability with limited computational complexity increment. Therefore, in this paper, we develop a complete RA scheme for 5G MIMO-NOMA systems, which has excellent performance while with low computational complexity for both perfect and imperfect CSI scenarios.
Bibliographical noteFunding Information:
Manuscript received January 28, 2017; revised May 15, 2017; accepted May 22, 2017. Date of publication July 17, 2017; date of current version December 22, 2017. This work was supported in part by the National Natural Science Foundation of China under Grant 61471008, Grant 61622101 and Grant 61571020, in part by the Ministry National Key Research and Development Project under Grant 2016YFE0123100, in part by the Open Research Fund of the State Key Laboratory of Integrated Services Networks under Grant ISN18-14, Xidian University, and in part by the National Science Foundation under Grant CNS-1343189. (Corresponding author: Xiang Cheng.) C. Chen, W. Cai, X. Cheng, and Y. Jin are with the State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100080, China, and also with the State Key Laboratory of Integrated Service Networks, Xidian University, Xi’an 710071, China (e-mail: email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org).
- Outage probability
- Resource allocation
- User selection