5G Backhaul Challenges and Emerging Research Directions: A Survey

摘要: 5G is the next cellular generation and expected to quench growing thirst for taxing data rates enable Internet of Things. Focused research standardization work have been addressing corresponding challenges from radio perspective while employing advanced features, such as network densification, massive multiple-input-multiple-output antennae, coordinated multi-point processing, inter-cell interference mitigation techniques, carrier aggregation, new spectrum exploration. Nevertheless, a bottleneck has emerged: backhaul. The ultra-dense heavy traffic cells should be connected core through backhaul, often with extreme requirements in terms capacity, latency, availability, energy, cost efficiency. This pioneering survey explains backhaul paradigm, presents critical analysis legacy, cutting-edge solutions, trends backhauling, proposes novel consolidated framework. A joint access proposed evaluation technologies which reinforces belief that no single solution can solve holistic problem. paper also reveals hidden advantages shortcomings are not evident when inspected an independent part network. key identifying essential catalysts believed jointly pave way solving beyond-2020 backhauling challenge. Lessons learned, unsolved challenges, vision thus presented.