1. Introduction  
1.2. Scope and Contributions  
1.3. Organization of the Paper  

2. Related Surveys  
2.1. NOMA’s Benefits  

3.1. Modulation and Coding for NOMA  
3.2. Cross-Layer Resource Allocation  

4. Integration of NOMA with Emerging Technologies  
4.2. VLC-NOMA  
4.3. UAV-NOMA Assisted Communications  

5. Applications of NOMA  
5.2. NOMA in Autonomous Networks/Robotic Communications  
5.3. NOMA in E-Health Systems  

6.1. Hardware Complexity  
6.2. Receiver Design  

7. Security Issues in NOMA  

8. Future Research Directions  
8.1. Optimal/low-complexity receiver design  
8.3. MIMO-NOMA and IoT  

9. Conclusion