Machine-type communications: current status and future perspectives toward 5G systems

TLDR: This study presents a roadmap from the current cellular technologies toward fully MTC-capable 5G mobile systems, and provides a clear mapping between the main MTC service requirements and their associated challenges.

Abstract: Machine-type communications (MTC) enables a broad range of applications from mission- critical 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 reduces 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 toward fully MTC-capable 5G mobile systems.

Figures

Figure 1. Current and envisioned cellular-based network architectures for supporting MTC services.

Table 2. Maximum coupling loss for LTE channels.

Figure 2. Network access procedure for data transmissions in LTE system.

Table 3. Potential coverage enhancement techniques.

Table 1. Examples of MTC applications and their requirements.

Full text

This is an electronic reprint of the original article.
This reprint may differ from the original in pagination and typographic detail.
Author(s):
Shariatmadari, Hamidreza & Ratasuk, Rapeepat & Iraji, Sassan &
Laya, Andrés & Taleb, Tarik & Jäntti, Riku & Ghosh, Amitava
Title:
Machine-type communications: current status and future perspectives
toward 5G systems
Year: 2015
Version: Post print
Please cite the original version:
Shariatmadari, Hamidreza & Ratasuk, Rapeepat & Iraji, Sassan & Laya, Andrés & Taleb,
Tarik & Jäntti, Riku & Ghosh, Amitava. 2015. Machine-type communications: current
status and future perspectives toward 5G systems. IEEE Communications Magazine.
Volume 53, Issue 9. 10-17. DOI: 10.1109/MCOM.2015.7263367.
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1
Machine-Type Communications: Current Status and Future
Perspectives Towards 5G Systems
List of Authors:
Hamidreza Shariatmadari
1
, Rapeepat Ratasuk
2
, Sassan Iraji
1
, Andrés Laya
3
, Tarik Taleb
1
,
Riku Jäntti
1
, Amitava Ghosh
2
Contact Authors:
1
{firstname.lastname@aalto.fi}, Aalto University, P.O. Box 13000, FI-00076, Finland
2
{firstname.lastname@nokia.com}, Nokia Networks, 1421 W. Shure Dr., Arlington Heights,
IL, USA
3
{lastname@kth.se}, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista,
Sweden
Abstract
Machine-type communications (MTC) enables a broad range of applications from mission-
critical 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
I. Introduction
Machine-type communications (MTC) or machine-to-machine communications (M2M) refer
to automated data communications among devices and the underlying data transport
infrastructure. The data communications may occur between an MTC device and a server, or
directly between two MTC devices [1]. MTC has great potential in a wide range of
applications and services. The potential applications are widespread across different
industries, including healthcare, logistics, manufacturing, process automation, energy, and
utilities.
The communications among MTC devices can be handled through different network
technologies. Point-to-point and multi-hop wireless networks, such as ad hoc networks,
sensor and mesh networks, have been considered as a means to provide Internet access for
devices, forming the so-called Internet of Things (IoT) [2]. For instance, IEEE 802.15.x with
its different amendments have been developed to serve variety of applications in personal
area networks [3]. IEEE 802.11ah is another technology that supports low-power
transmissions with extended coverage range in Wi-Fi networks [4]. However, these
technologies suffer from some fundamental limitations that confine their wide
implementation for MTC. The main drawback is the lack of efficient backhaul. This limits the
network scalability and coverage. Another issue is their operation over unlicensed frequency
bands, making the communication links unreliable and susceptible to interference.
Therefore, it is challenging to support applications requiring a high degree of reliability.
Cellular systems, such as Long Term Evolution (LTE), are considered as alternative solutions
for the wide provision of MTC applications. Their ubiquitous presence saves the network
installation cost and provides widespread coverage and mobility support. In addition, since
cellular systems are regulated and interference controlled, their communication links are
more reliable.
Until recently, cellular systems are mainly designed and optimized to serve traffic from
human-to-human (H2H) communications, which are generally characterized by bursts of
data during active periods with a higher demand on downlink. However, major MTC
applications have different traffic characteristics: usually small and infrequent data

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generated from a mass of MTC devices imposing a higher traffic volume on uplink. Examples
of these infrequent data transmissions, which are uplink-centric, include advanced metering
infrastructure and vending machines. Furthermore, MTC devices are also different from H2H
equipment: most MTC devices are inexpensive with limited computational or power
resources. These distinct features have raised new technical challenges to enable cellular-
based MTC widely [2], [5]. Therefore, these challenges must be effectively addressed for the
future broadband wireless communications towards 5G systems in order to fully support
MTC. In this vein, the Third Generation Partnership Project (3GPP) has also launched
numerous activities to support MTC for future releases of LTE network, referred to as LTE-
Advanced (LTE-A). 3GPP has already specified the general requirements for MTC
applications and identified issues and challenges related to them. Network and device
modifications have been considered in upcoming releases of LTE standardization to facilitate
and better support the integration of MTC [6].
Various methods, use cases, and requirements for 5G systems have been studied lately to
support diverse set of communications. Some of the visions and early results have been
summarized in [7]. In this article we aim at giving a thorough overview of the current status
of MTC in 4G systems or more specifically in LTE and LTE-A systems (in the rest of this
article, LTE and LTE-A are used interchangeably), and in particular giving perspectives
towards 5G mobile systems. The remainder of this article is organized as follows. We review
different MTC service functions and address the main requirements that they impose to
cellular systems. After that, we describe the current and envisioned cellular-based MTC
network architectures. We provide some of the potential solutions and enhancements for
meeting the requirements. Finally, conclusions are drawn.
II. MTC Service Functions and their Requirements
MTC enables offering a diverse range of new services and applications. The potential MTC
applications have very different features and requirements which imply constraints on the
network technology as well as on MTC devices. Table 1 provides some notable MTC service
functions and application examples, including their imposed requirements on cellular
systems to be served as radio access technologies.

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Table 1. Examples of MTC applications and their requirements.
Metering applications facilitate automatic collecting utility measurements. The gathered
information can be utilized for online system optimization and billing purposes. In general,
the metering devices generate infrequent and small amounts of data. In addition, the density
of metering devices is usually high. These features entail that the network technology be
capable of handling small bursts of data from a large number of devices. The metering
devices may be deployed in indoor environment; hence, they require enhanced coverage for
their connectivity. Further examples of MTC services are control and monitoring systems.
They enable remote system controlling or optimization. Reliable communications are
required for most of these systems, while low-latency data transmissions are essential for
many real-time control systems. Among others, tracking applications assist in managing
fleets, locating assets, and preventing theft of equipment. A large-scale connectivity is
necessary for supporting these applications. Furthermore, MTC devices used for these
applications are generally equipped with batteries and expected to operate for a long period
of time without the need to replace the batteries. Hence, very low power consumption is vital
for their operations. For payment applications, security is the most important concern.
Security and public safety services need reliable communications with low-latency in
addition to a high level of data security to ensure flawless operations.

Frequently asked questions

Q1. How can The authorensure the coverage for the meter?

To ensure the coverage for the meter, at maximum coupling loss of 155.7 dB, the downlink data channel can be transmitted employing 40 repetitions, frequency hopping, and 3dB PSD boosting. 

Q2. What are the contributions mentioned in the paper "Title: machine-type communications: current status and future perspectives toward 5g systems" ?

The ubiquitous deployment of these systems saves the network installation cost and provides mobility support. This article provides a clear mapping between the main MTC service requirements and their associated challenges. This study presents, in part, a roadmap from the current cellular technologies towards fully MTC-capable 5G mobile systems. The goal is to develop a comprehensive understanding of these challenges and the potential solutions. 

Q3. What is the way to provide reliable links?

Massive multi-input multi-output (MIMO) antennas can provide reliable links bybenefiting from spatial diversity and mitigating effects of fast fading, beamforming, and zero forcing caused by multi-user interference. 

Q4. What is the important metric for choosing a radio technology?

Energy-efficiency is a decisive metric for choosing a radio technology, particularly for MTC applications whereby MTC devices have limited energy budget. 

Q5. What can be done to reduce the power consumption of MTC devices?

Deploying MTC gateways and supporting multi-hop communications can reduce thepower consumption by allowing MTC machines to transmit with lower power. 

Q6. What is the main concern for supporting D2D communications?

Supporting D2D communications between nearby MTC devices can reduce the powerconsumption by allowing transmissions with lower power. 

Q7. What are some solutions for the security challenges of MTC?

Provide ultra-reliable communications with low-latencyUltra-reliable communications are vital for safe operation of some MTC applications, such as control and monitoring systems, cloud-based systems, and vehicle-to-vehicle wireless coordination. 

Q8. What are the main reasons for the low power consumption of MTC devices?

In order to accommodate low power consumption devices in LTE system, differentmodifications have been proposed, including: Modifying signaling and MAC protocols which can boost the energy efficiency byreducing the time that radio should be turned on. 

Q9. How can you ensure high level of security for your MTC?

Ensure high level of securityLTE system provides security for communications by integrating various security algorithms, such as authentication, integrity and encryption. 

Q10. What is the main reason for using asymmetric security schemes?

Using asymmetric security schemes enables moving the burden of requiredcomputations to the network domain or gateways, which usually have high computation power. 

Q11. What is the main purpose of the semi-persistent scheduling?

The semi-persistent scheduling can also eliminate scheduling delays in feedback control applications, as sensors and controllers usually produce data periodically. 

Q12. What is the main concern for supporting MTC devices?

Typical LTE devices have been designed to provide broadband services and are therefore overdesigned for low-rate and delay-tolerant MTC services. 

Q13. How many locations in the network are used for aggregating data?

Data or signalingmessage aggregation may occur at different locations in the network (e.g., MTC device, MTC gateway, eNodeB, or MME) [11], [14]. 

Q14. What is the purpose of the coverage enhancement feature for MTC?

In addition, as discussed earlier, low-cost MTC UE will decrease the coverage due to reduced capabilities such as single receive antenna and lower power. 

Q15. What are some of the applications that require reliable communications?

In some applications, reliable communications are required mainly for exchangingdata between MTC devices that are located in close proximity. 

Q16. What are the disadvantages of low-cost MTC devices?

In addition, low-cost MTC devices may not be able to perform existing security schemes since they have limited computation power. 

Q17. What is the new low-cost UE category?

In Release 12, 3GPP has introduced a new low-cost MTC UE category (calledCategory-0 UE) with the following reduced capabilities: Support of a single antenna instead of at least two receive antennas for other UEs.