Low Electromagnetic Emission Wireless Network Technologies: 5G and beyond
2: University of Surrey, Guildford, UK
Mobile communication systems rely on radiofrequency waves to operate. Given the popularity and ubiquity of mobile communication devices as well as network densification, the level of Electromagnetic Field (EMF) exposure to the public is expected to rise significantly over the next few years. Although there is no clear evidence linking short-term exposure to EMF emission from wireless communication systems with adverse health effects, the International Agency for Research on Cancer (IARC) has concluded that EMF radiation is possibly carcinogenic. To cope with the concerns of the general public, the European Environmental Agency has recommended non-technical precautionary approaches to minimize exposure to EMF emissions. Rather than relying on these non-technical approaches, EMF, latency, network resilience and connection density, alongside traditional criteria such as spectral efficiency and energy efficiency are expected to take centre stage in the development of 5G systems. This book focuses on innovative EMF exposure research for future generations of mobile and wireless communications. This timely publication highlights the novel work done on reducing EMF emissions in future mobile communication systems and how to develop smart integrated technical solutions.
Inspec keywords: telecommunication network management; wearable antennas; electromagnetic fields; telecommunication network planning; electric potential; minimisation; radio equipment; millimetre wave antennas; flexible electronics; radiation monitoring; cellular radio; frequency division multiple access; telecommunication power management; energy conservation; automatic repeat request; OFDM modulation; 5G mobile communication; telecommunication scheduling; telecommunication network reliability; regulation
Other keywords: OFDMA systems; 5G cellular networks; large-scale EMF characterization; heterogeneous networks environments; EMF effects; EMF evaluation; EMF reduction techniques; EMF emission-aware resource allocation; ultra-reliable low-latency communications; low-exposure user terminal radio design; electromagnetic field monitoring tools; public mobile networks architecture; EMF regulations; EMF emission minimization; RF device; millimetre-wave flexible wearable antenna design; EMF exposure definition; uplink OFDM systems; real network deployments; energy-efficient inter-frequency small cell discovery; HARQ; EMF metrics; multicell uplink scheduling; low electromagnetic emission wireless network technologies; EMF characterisation
Subjects: Radio links and equipment; Classical electromagnetism; Communication system theory; Education and training; Reliability; Antennas; Electric and magnetic fields; Modulation and coding methods; Telecommunication applications; Publications of lectures (advanced institutes, summer schools, etc.); Energy utilisation; Optimisation techniques
- Book DOI: 10.1049/PBTE084E
- Chapter DOI: 10.1049/PBTE084E
- ISBN: 9781785618482
- e-ISBN: 9781785618499
- Page count: 305
- Format: PDF
-
Front Matter
- + Show details - Hide details
-
p.
(1)
-
Part I. EMF evaluation and characterisation
1 EMF exposure definition, metrics, effects and regulations
- + Show details - Hide details
-
p.
3
–22
(20)
This introductory chapter provides an overview of Electromagnetic Field (EMF) exposure from mobile systems. Electromagnetic (EM) radiation in the Radio-Frequency (RF) spectrum range is described, with established EMF exposure metrics as well as the recent EMF Exposure Index (EI), and public perceptions of EMF exposure are discussed. Finally, international EMF exposure guidelines and limits are presented.
2 Electromagnetic field (EMF) monitoring tools
- + Show details - Hide details
-
p.
23
–52
(30)
In this chapter, we focus on measurement devices and simulation tools used to establish EMF exposure levels with given precision and uncertainty. First, we establish the types of EMF exposure metrics to answer what we want to measure. Second, we discuss different equipment, tools, protocols, which are used to measure the EMF exposure levels today. The third part is focused to address the future needs in terms of EMF exposure estimation and how to address them. A case study is presented with implementation of solutions adapted to a smart-city scenario with a quasi-realtime EMF exposure estimation and monitoring. Finally, conclusions are drawn and perspectives are identified.
3 Large-scale EMF characterization considering real network deployments
- + Show details - Hide details
-
p.
53
–83
(31)
Traditionally, the assessment of electromagnetic field (EMF) exposure due to radio -frequency (RF) communications has focused on individual users, separately considering the exposure induced by personal devices, and that caused by network elements [I]. However, various studies have shown that there is a strong correlation between power emitted by users' devices and that received from base stations [2]. In order to provide a more accurate means to estimate the population exposure, the low-EMF exposure networks (LEXNET) project has proposed a novel metric, coined exposure index (EI), which is associated with a wireless telecommunication network, considering large areas and prolonged periods of time. In addition, the EI combines both the exposure induced by personal devices with that coming from network access elements, leading to new key performance indicators (KPIs) usable for network planning and operation.
4 EMF exposure in heterogeneous networks environments
- + Show details - Hide details
-
p.
85
–113
(29)
Future networks will be composed of a network of networks, consisting of many multiple-access technologies, multiple bands and widely varying coverage areas, all self-organised and optimised, with seamless roaming among different systems. The Electromagnetic Field (EMF) exposure in this type of heterogeneous networks involves several aspects that need to be carefully addressed. In this chapter, an overview of the current methods to assess EMF levels in the 0.4-6 GHz band is presented. Different methods used to assess exposure in uplink (UL) and downlink (DL) scenarios are detailed, the impact of body shadowing on wearable exposimeter EMF measurements is assessed and the global exposure in heterogeneous networks composed of Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE) and Wi-Fi systems, in different scenarios, varying usage, mobility and number of users, is evaluated.
5 Architecture of public mobile networks and its impact on EMF exposure
- + Show details - Hide details
-
p.
115
–139
(25)
This chapter illustrated the impact of network architecture on EMF exposure of a person and of the population in an area. The main factors shaping the EMF exposure are technology used, radio conditions and network load conditions, along with the service used under these circumstances. Network architecture, i.e. technology and topology used for an area, with the set of network policies, determines network behaviour for given traffic fluctuations in the area and radio and network conditions for every single user. In this complex environment with constant and instant changes and mutual dependencies between factors affecting the EMF exposure, statistical analysis may be performed and some conclusions drawn.
-
Part II. EMF reduction techniques
6 EMF emission-aware resource allocation for uplink OFDM systems
- + Show details - Hide details
-
p.
143
–165
(23)
Two schemes - offline and online - for minimizing the total EMF emission in the uplink of OFDMA systems have been proposed in this chapter. The offline EMF emission reduction scheme is based on the assumption that the network can predict the long-term CSI of all the users for allocating them on subcarriers. Then an optimal rate -based water -filling is performed to obtain the rate and power allocations of each allocated user on each subcarrier allocated to the user. On the other hand, the online EMF emission reduction scheme, which is based on short-term CSI knowledge, allocates power to users by minimizing the transmit energy per bit of each user. Simulation results show that the proposed offline scheme performs close to the optimal solution and that it significantly outperforms existing SE- and EE -based schemes, by up to 3 and 2 orders of magnitude, respectively. Accordingly, the proposed online scheme outperforms the SE- and EE -based schemes by up to 2.5 and 2 orders of magnitude, respectively. It has also shown that EMF emission of the offline scheme is inversely related to the transmission window, which makes it suitable for delay tolerant transmissions. Additionally, the offline scheme proves to be very robust against the effects of imperfect channel prediction.
7 Multicell uplink scheduling for EMF emission minimization in OFDMA systems
- + Show details - Hide details
-
p.
167
–184
(18)
This chapter proposes a novel scheduling scheme for minimizing electromagnetic (EM) emission in the uplink of a multicell (MC) multiuser orthogonal frequencydivision multiple access (OFDMA) wireless communication system, while maintaining a specified quality of service (QoS) constraint.
8 EMF: RF device end of things – low-exposure user terminal radio design concepts
- + Show details - Hide details
-
p.
185
–205
(21)
The most significant exposure, as has been seen through metrics discussed earlier in this book, is subject to the uplink from mobile terminal devices that are transmitting electromagnetic fields (EMFs) in proximity to the user, or other individuals that are in close proximity to any wireless device. Exposure from the downlink, on the other hand, is substantially less. Support of low-exposure mobile networks therefore warrants the need to design and implement user terminal radios in such a way that they will not radiate EMFs for unnecessary lengths of time, with excessive levels of transmit power or in undesired directions. Before discussing the technologies that can be used to reduce exposure from a mobile terminal radio, it is first useful to categorise the practical ways in which exposure from a mobile user terminal can be measurably reduced.
9 Millimetre-wave flexible wearable antenna design and challenges for 5G and beyond
- + Show details - Hide details
-
p.
207
–230
(24)
In this chapter, a Ka-band flexible antenna design is presented to address the 5G demands, and fabricated by two advanced methods of laser prototyping and inkjet printing for the comparative performance analysis. Post -printing process, i.e. heat sintering of the inkjet-printed prototype, is usually time-consuming, which has been significantly improved by proposing a novel method in this chapter to utilize a heat press instead of the oven to efficiently reduce the sintering duration from several minutes to just a few seconds. The antenna design is extended further in an antenna array for the gain enhancement. The antenna array proposed in this chapter is a potential candidate for the 5G flexible wireless devices due to its high performance attributes of gain and bandwidth, conformity and ease of integration, as well as safer to human body interactions because of lower penetration characteristics of mmWaves.
10 Reducing EMF emissions in ultra-reliable low-latency communications with HARQ
- + Show details - Hide details
-
p.
231
–250
(20)
Using HARQ is an efficient mean of adding diversity to communications systems without using unnecessary resources, and when properly tuned, it can be beneficial even for URLLC applications. We have shown how properly designing the scheme can lead to important reductions in the maximum EMF radiation being output by the communication system. In the context of URLLC, several suboptimal aspects of HARQ have to be improved and fine-tuned with latency in mind. However, even in those cases, clever engineering and design can overcome possible added latencies and harvest the efficient resource usage of HARQ. This efficient use of resources is relevant as it enables devices to communicate using less energy and therefore reduces the EMF emission, which is particularly relevant when considering the massive scale of deployments foreseen for the near future.
11 Reducing EMF via energy-efficient inter-frequency small cell discovery
- + Show details - Hide details
-
p.
251
–274
(24)
Ultra-densification and increased bandwidth are promising 5G technologies envisaged for meeting the ever-increasing mobile traffic demands. Deploying complementary small cells operating in the higher frequency bands on an existing macro layer operating on the traditional lower frequency band is recognized as a very attractive solution for providing high capacity and seamless ubiquitous coverage. However, existing small cell discovery mechanisms are tailored for the macro layer and using them will lead to an increase in the user equipment (UE) energy consumption and consequently an increase in the generated electromagnetic field (EMF). This chapter summarizes various small cell discovery mechanisms that are designed for an energy-efficient and EMF-efficient discovery of the small cells. It further presents a framework for evaluating the optimal small cell discovery periodicity which also leads to the reduction in the generated EMF in a 5G heterogeneous network.
12 Conclusion and future perspectives
- + Show details - Hide details
-
p.
275
–276
(2)
This book presents the current and future trends in electromagnetic field (EMF) exposure assessment, measurement, limitation and mitigation for mobile and wireless communication systems. The book is divided into two parts, with the first part providing an overview of EMF exposure in terms of exposure metrics, guidelines and limits as well as various techniques and mechanisms for monitoring and evaluating EMF exposure in mobile networks. It has been established in this part that the technology used, channel and network loading conditions, and the type of service used as well as user behaviour determine EMF exposure levels over any given area.
-
Back Matter
- + Show details - Hide details
-
p.
(1)