Millimeter-wave frequencies between 6 and 100 GHz provide orders of magnitude larger spectrum than current cellular allocations and allow usage of large numbers of antennas for exploiting beamforming and spatial multiplexing gains. In this article, we describe the main design concepts when integrating mmWave RANs into 5G systems, considering aspects such as spectrum, architecture, and backhauling/fronthauling. The corresponding RRM challenges, extended RRM functionalities for 5G mmWave RAN, and RRM splits are addressed. Finally, based on these discussions, a framework is proposed that allows joint backhaul and access operation for 5G mmWave RAN, which we envisage as one of the key innovative technologies in 5G. The proposed framework consists of a joint scheduling and resource allocation algorithm to improve resource utilization efficiency with low computational complexity and to fully exploit spatial multiplexing gain for fulfilling user demands.

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Radio Resource Management Considerations for 5G Millimeter Wave Backhaul and Access Networks

This paper studies the performance of multi-hop and mesh networks composed of millimeter wave-based radio frequency (RF) and free-space optical (FSO) links. The results are obtained in cases with and without hybrid automatic repeat request (HARQ). Using the central limit theorem as well as other state-of-the-art approximation schemes, we derive closed-form expressions for the networks’ outage probability and ergodic achievable rates. We also evaluate the effect of various parameters such as power amplifiers efficiency, number of antennas as well as different coherence times of the RF and the FSO links on the system performance. Finally, we determine the minimum number of the transmit antennas in the RF link such that the same rate is supported in the RF- and the FSO-based hops. The results show the efficiency of the RF-FSO setups in different conditions. Moreover, HARQ can effectively improve the outage probability/energy efficiency, and compensate for the effect of hardware impairments in RF-FSO networks. For common parameter settings of the RF-FSO dual-hop networks, outage probability of 10−4 and code rate of 3 nats-per-channel-use, the implementation of HARQ with a maximum of 2 and 3 retransmissions reduces the required power, compared to cases with open-loop communication, by 13 and 17 dB, respectively.

On the Performance of Millimeter Wave-Based RF-FSO Multi-Hop and Mesh Networks

The mobile demands and future business context are anticipated to be resolved by the fifth-generation (5G) of mobile communication systems. It is expected to provide an utterly mobile device, connected society, and support the demanding services of various use cases (UCs). This is intended to meet the demand requirement by providing services at tens of Gbps in terms of data rates, higher mobility range, lower latencies, and massive connectivity density devices per square kilometer. A comprehensive and up-to-date survey of the different developed and proposed use cases is presented in this paper. The first part of the paper presents the overview of the new 5G Architecture by introducing new features such as the new radio interface (New Radio), an overview of the 5G Core Network, minimum requirements, and the Radio Access Network, 5G spectrum requirements and other fundamentals of the network. Secondly, a detailed review of the developed and proposed use cases for 5G communications by the standards development organizations (SDO) and other key players in mobile communication is provided. Thirdly, we went ahead to propose spectrum bands for the deployment of the various use cases based on the low-, mid-, and high-band spectrum and further classified the use cases with respect to their relevance and family, identifying the IMT-2020 test environments and the usage scenarios derived by the 3GPP, fourthly, the channel capacity and the bandwidth of the spectrum was studied, simulated and compared to ascertain the spectrum proposed in this paper for each UC family. Hence, this paper serves as a guideline for understanding the future 5G deployment scenarios in various environments. This would allow system developers to design and implement 5G channel characterization models specific to the usage scenarios to meet the system requirements.

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5G Mobile Communication Applications: A Survey and Comparison of Use Cases

The fifth generation (5G) telecommunications standards are being developed to meet the growing demands for high-speed wireless networks (i.e., few tens of Gigabits per second). The 5G standard stems largely from an increasing number of users and plethora of different devices, collectively referred to as smart devices, connecting to a network as part of Internet-of-Things (IoT). A few potential technologies have emerged for 5G such as millimeter waves, massive multiple-input multiple-output, and small cell communications. Although these technologies would satisfy the requirements of 5G, there is a complementary alternative wireless technology of optical wireless communications (OWC), which is being considered. As part of OWC, visible light communications (VLC) and optical camera communications (OCC) are the most attractive options for 5G networks and beyond. VLC with huge frequency spectrum integrated with IoT can open up a wide range of indoor and outdoor applications as part of future smart environments. This paper provides an overview of the all-optical IoT (OIoT) focusing on VLC and OCC based potential applications and challenges as part of 5G standards.

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Optical Internet of Things within 5G: Applications and Challenges

Millimeter wave (mmW) communications is the key enabler of 5G cellular networks due to vast spectrum availability that could boost peak rate and capacity. Due to increased propagation loss in mmW band, transceivers with massive antenna array are required to meet link budget, but their power consumption and cost become limiting factors for commercial systems. Radio designs based on hybrid digital and analog array architectures and the usage of radio frequency (RF) signal processing via phase shifters have emerged as potential solutions to improve energy efficiency and deliver performances close to digital arrays. In this paper, we provide an overview of the state-of-the-art mmW massive antenna array designs and comparison among three architectures, namely digital array, sub-array, and fully-connected hybrid array. The comparison of performance, power, and area for these three architectures is performed for three representative 5G use cases, which cover a range of pre-beamforming SNR and multiplexing regimes. This is the first study to comprehensively model and analyze all design aspects and criteria including: 1) optimal linear precoder, 2) impact of quantization error in DAC and phase shifters, 3) RF signal distribution network, 4) power and area estimation based on state-of-the-art mmW circuits including baseband precoding, digital signal distribution, DACs, oscillators and mixers, phase shifters, RF signal distribution, and power amplifiers. The results show that the digital array is the most power and area efficient compared against optimal design for each architecture. Our analysis shows digital array benefits greatly from multi-user multiplexing. The analysis also reveals that sub-array is limited by reduced beamforming gain due to array partitioning, and system bottleneck of the fully-connected hybrid architecture is the excessively power hungry RF signal distribution network.

Performance, Power, and Area Design Trade-offs in Millimeter-Wave Transmitter Beamforming Architectures.

mmMAGIC (Millimetre-Wave Based Mobile Radio Access Network for Fifth Generation Integrated Communications) is an EU funded 5G-PPP project, whose overall objective is to design and pre-develop a mobile radio access technology (RAT) operating in the 6–100 GHz range, capable of impacting standards and other relevant fora. The focus of the project is on extreme Mobile Broadband, which is expected to drive the 5G requirements for massive increase in capacity and data-rates. This paper elaborates on some 5G key research areas such as: identification of the most compelling use-cases and Key Performance Indicators (KPIs) for future 5G systems, advantages and challenges of millimeter-wave (mmWave) technologies, channel measurements and channel modeling, network architecture; and the design of a new mobile radio interface including multi-node and multi-antenna transceiver architecture.

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5G systems: The mmMAGIC project perspective on use cases and challenges between 6–100 GHz

In this deliverable use cases and KPIs of interest for mmMAGIC are characterized. Eight use
cases suitable for 5G systems operating in the range 6-100GHz are identified in terms of
requirements. In particular, the following use cases are analyzed: Media on demand; Cloud
services; Dense urban society with distributed crowds; Smart offices; Immersive 5G early
experience in targeting hot spots; 50+Mbps everywhere; Moving hot spots; Tactile
internet/video augmented robotic control and remote-robot manipulation surgery. For each of
the use cases, the more critical KPIs are identified and the gap from the current technology
is also described.
An analysis of frequency ranges for future 5G systems between 6 GHz and 100 GHz is reported. A frequency assessment study is conducted in order to compare the frequency ranges for the suitability of delivering key KPIs.

Aditya Amah

Papers

5G systems: The mmMAGIC project perspective on use cases and challenges between 6–100 GHz

Use case characterization, KPIs and preferred suitable frequency ranges for future 5G systems between 6 GHz and 100 GHz