Machine-type communications (MTC) enables a broad range of applications from missioncritical services to massive deployment of autonomous devices. To spread these applications widely, cellular systems are considered as a potential candidate to provide connectivity for MTC devices. The ubiquitous deployment of these systems saves the network installation cost and provides mobility support. However, based on the service functions, there are key challenges that currently hinder the broad use of cellular systems for MTC. This article provides a clear mapping between the main MTC service requirements and their associated challenges. The goal is to develop a comprehensive understanding of these challenges and the potential solutions. This study presents, in part, a roadmap from the current cellular technologies towards fully MTC-capable 5G mobile systems.2
The upcoming fifth generation (5G) wireless communication system is expected to support a broad range of newly emerging applications on top of the regular cellular mobile broadband services. One of the key usage scenarios in the scope of 5G is ultra-reliable and low-latency communications (URLLC). Among the active researchers from both academy and industry, one common view is that URLLC will play an essential role in providing connectivity for the new services and applications from vertical domains, such as factory automation, autonomous driving and so on. The most important key performance indicators (KPIs) related to URLLC are latency, reliability and availability. In this paper, after brief discussion on the design challenges related to URLLC use cases, we present an overview of the available technology components from 3GPP Rel-15 and potential ones from Rel-16. In addition, coordinated multi-cell resource allocation methods are studied. From the system level simulation results in an urban macro environment, it can be observed that effective multi-cell cooperation, more specifically soft combining, can lead to a significant gain in terms of URLLC capacity.
Abstract-The fifth generation (5G) of cellular networks is expected to provide connectivity for a wide range of services. This requires the network to encounter novel features. Ultrareliable communications (URC) is one of the considered features, which provides a certain level of communication service almost all the time. This is essential in order to support mission-critical applications, such as industrial automation, public safety, and vehicular communications. This paper studies link adaptation optimization for URC, considering errors in both data and feedback channels. As the implementation of optimal link adaptation is challenging, particularly, for downlink transmissions due to the limited feedback channel, a simple link adaption scheme is also proposed. Results reveal that the performances of the proposed and optimal link adaptation schemes are close. Hence, the proposed scheme can be utilized to efficiently support URC in cellular networks.
The fifth generation (5G) of wireless systems holds the promise of supporting a wide range of services with different communication requirements. Ultra-reliable low-latency communications (URLLC) is a generic service that enables mission-critical applications, such as industrial automation, augmented reality, and vehicular communications. URLLC has stringent requirements for reliability and latency of delivering both data and control information. In order to meet these requirements, the Third Generation Partnership Project (3GPP) has been introducing new features to the upcoming releases of the cellular system standards, namely releases 15 and beyond. This article reviews some of these features and introduces new enhancements for designing the control channels to efficiently support the URLLC. In particular, a flexible slot structure is presented as a solution to detect a failure in delivering the control information at an early stage, thereby allowing timely retransmission of the control information. Finally, some remaining challenges and envisioned research directions are discussed for shaping the 5G new radio (NR) as a unified wireless access technology for supporting different services.
Abstract-Fifth generation of cellular systems is expected to widely enable machine-type communications (MTC). The envisioned applications and services for MTC have diverse requirements which are not fully supported with current wireless systems. Ultra-reliable communications (URC) with low-latency is an essential feature for mission-critical applications, such as industrial automation, public safety, and vehicular safety applications. This feature guarantees a communication service with a high level of reliability. This paper investigates the feasibility and efficiency of URC over wireless links. It also analyzes the effectiveness of different transmission methods, including spatial diversity and support of hybrid automatic repeat request (HARQ). Finally, the importance of reliable feedback information is highlighted.
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