Source-linked AI summary
Emerging Technologies and Research Challenges for 5G Wireless Networks
Woon Hau Chin, Zhong Fan, Russell J. Haines
TL;DR
Growing mobile data demand motivates research into technologies for future 5G standards. The paper surveys emerging technologies, their standardization status, and associated research challenges, concluding that future 5G networks will combine enabling technologies whose integration is the biggest challenge.
Problem
The paper addresses how future 5G networks can respond to rapidly increasing mobile data demand while improving capacity, coverage, connectivity, and energy efficiency.
Method
The paper surveys emerging 5G technologies, classifies their goals and network functionalities, reviews standardization bodies, and identifies associated research problems.
Results
The paper concludes that future 5G wireless networks will combine different enabling technologies.
Takeaways & Limitations
Making the enabling technologies work together is identified as the biggest challenge for future 5G wireless networks.
Takeaways & Limitations
Wireless SDN remains at its infancy, with unresolved infrastructure design, standardization, NetworkOS, and security issues.
Abstract
from arXiv · showhide
As the take-up of Long Term Evolution (LTE)/4G cellular accelerates, there is increasing interest in technologies that will define the next generation (5G) telecommunication standard. This paper identifies several emerging technologies which will change and define the future generations of telecommunication standards. Some of these technologies are already making their way into standards such as 3GPP LTE, while others are still in development. Additionally, we will look at some of the research problems that these new technologies pose.
Introduction
Rising mobile data demand is shifting attention from 4G toward 5G, although the future standard remains unsettled. The paper surveys emerging technologies intended to improve capacity, coverage, connectivity, and energy efficiency, alongside their research challenges.
- Mobile data traffic was forecast to grow more than 24-fold from 2010 to 2015 and more than 500-fold from 2010 to 2020.
- 5G is expected to pursue higher data rates while placing greater emphasis on coverage and user experience.
- Emerging participation in IEEE 802.11 HEW suggests growing interest in amalgamating technologies for future connectivity and data rates.
- The paper identifies and ranks technologies, classifies their goals and network functionalities, surveys standardization bodies, and outlines resulting research challenges.
1. Heterogeneous Networks
Heterogeneous 5G networks combine small cells, separated control and user planes, multiple radio technologies, and device-to-device links. Their deployment introduces interference, access, discovery, and link-setup challenges.
- Small Cells: Smaller cells can increase area spectral efficiency, reduce transmit power, improve indoor coverage, and offload macro-cell traffic.
- Small Cells: Heterogeneous networks concurrently operate macro-, pico-, and femto-base stations to provide flexible coverage and improve spectral efficiency.
- New Carrier Type: Separating control and user planes lets a macro cell maintain connectivity while a small cell provides high-throughput data transport.
- New Carrier Type: Removing cell-specific control signals allows small cells to switch off without data, improving cell-edge user throughput by up to 70 percent and reducing macro-node energy consumption by 20 percent at low loads.
- Multiple Radio Access Technologies: Future heterogeneous networks may mix cellular, WLAN, and device-to-device technologies, but dense WLAN use can result in poor throughput.
- Multiple Radio Access Technologies: D2D communications allow nearby terminals to share radio access or exchange information directly, while power control can reduce interference.
- Challenges of Heterogeneous Networks: Key challenges include inter-cell interference, distributed interference coordination, redesigned medium access control, and D2D discovery and link setup at high device density.
2. Software Defined Cellular Networks
Software defined networking offers a programmable, open, and flexible approach to managing future cellular networks, but its architecture and deployment remain unresolved. Scalability, robustness, standardization, and security are central challenges.
- Architecture: SDN decouples the logically centralized control plane from the network data plane, abstracting low-level networking functions into virtual services.
- Architecture: The ONF architecture describes SDN as directly programmable, open through vendor-neutral APIs, and agile through dynamic resource configuration.
- Cellular SDN: Applying SDN to mobile networks may simplify network management, support new services, and separate network services from physical infrastructure through open APIs and virtualization.
- Cellular SDN: SDN can provide fine-grained resource control for applications with different latency, throughput, priority, and QoS requirements.
- Research Challenges: The industry lacks consensus on a unified 5G architecture, while cellular SDN must address scalability across many small cells and devices and maintain robustness.
- Research Challenges: Wireless SDN remains at an early stage, with unresolved infrastructure design, programmable-interface standardization, multi-vendor NetworkOS, and security issues.
3. Massive MIMO and 3D MIMO
Massive MIMO uses very large antenna arrays for diversity, path-loss compensation, and high-resolution beamforming, while 3D MIMO adds beam control in both horizontal and vertical directions. Their adoption depends on solving channel-estimation, feedback, interference, processing, and channel-model challenges.
- Massive MIMO: Massive MIMO uses many antenna elements to provide diversity, compensate for path loss, and enable high-resolution beamforming, especially at higher frequencies.Its antenna elements can be miniaturized for higher-frequency operation.
- Massive MIMO: Massive MIMO can purportedly increase capacity by several orders while improving radiated energy-efficiency.Its many degrees of freedom can be exploited through beamforming when channel state information is available.
- Massive MIMO: Massive MIMO faces challenges from costly channel estimation and feedback, pilot contamination, thermal noise, fast data processing, and inadequate channel models.Current consideration focuses mainly on TDD because channel estimation and feedback are prohibitively costly, while channel calibration remains difficult.
- 3D MIMO: 3D MIMO extends beamforming to horizontal and vertical directions, enabling further sectorization within a cell.Like Massive MIMO, it requires new channel models.
4. Machine to Machine Communications
M2M communications introduce autonomous devices, restrictive operational constraints, and traffic patterns that do not fit current network architectures. The paper describes oneM2M’s effort toward common service-layer specifications while highlighting massive access, security, and privacy challenges.
- M2M context: M2M applications involve autonomous communication among devices such as smart-energy components, home appliances, and transportation systems.Their operation often faces restrictive power, size, and complexity requirements.
- M2M traffic: Short, periodic, and bursty M2M traffic does not fit readily within current network architectures, requiring extensions and modifications.
- oneM2M standardization: oneM2M was formed in 2012 to develop global, access-technology-agnostic service-layer specifications for M2M.Participants harmonized contributions from different standards organizations, whose proposals often differed in vocabulary and technical approaches.
- oneM2M architecture: The oneM2M architecture places Common Service Functions within Common Service Entities and defines interfaces to applications and underlying network services.It supports service- and resource-oriented architectures and adopts a stateless RESTful design with uniquely addressable entities.
- Research challenges: M2M systems must address massive access, which can cause radio-access-network congestion and overload when many devices share a cell.Proposals include back-off adjustment, access class barring, and M2M prioritization, but none is widely acknowledged as the solution.
- Research challenges: M2M deployment also requires security and privacy protections covering attributes such as authenticity, authority, integrity, and confidentiality.Privacy is particularly important for broad deployment and consumer acceptance across sectors such as e-health and smart metering.
5. Other Technologies
Other candidate 5G technologies address spectrum, data, positioning, and network integration. The paper presents beyond-6-GHz and millimetre-wave exploration, licensed spectrum sharing, big-data infrastructure, indoor positioning, and the broader challenge of making diverse technologies work together.
- Spectrum and frequencies: Bandwidth expansion beyond 6 GHz and into millimetre-wave frequencies is being studied because sub-6-GHz spectrum is limited.Studies of 28 GHz and 38 GHz examine propagation characteristics in different environments.
- Spectrum and frequencies: Licensed Spectrum Access allows authorized users to access licensed spectrum under conditions set by the licensee.It is intended to use under-utilized spectrum while preserving the primary user’s quality of service.
- Big data: Big data creates 5G challenges in infrastructure support, network architecture, and extracting useful intelligence from large data volumes.Potential platforms combine cloud computing, software-defined networking, and network function virtualization.
- Indoor positioning: Accurate indoor positioning can provide network information for resource allocation and quality-of-service improvement and enable location-based applications.Examples include position-based handover, resource allocation, and location-based services.
- Conclusion: The paper concludes that future 5G networks will combine different enabling technologies, with integration as the biggest challenge.It frames the work as an overview of emerging technologies and the research problems they present.
Biographies
The paper includes tables and figures organizing enabling technologies, their taxonomy, and selected 5G architectural concepts.
- Table 1 presents different enabling technologies for future wireless standards.
- Table 2 presents a taxonomy of enabling technologies.
- Figure 1 depicts separation of control and user planes.
- Figure 2 depicts the SDN architecture.
- Figure 3 depicts possible sectorization for 3D-MIMO.