Next Generation Wireless Terahertz Communication Networks

Saim Ghafoor, Mubashir Husain Rehmani, Alan Davy, Saim Ghafoor, Mubashir Husain Rehmani, Alan Davy

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000416374
• Edition: 1
• Topic: Informatique
• Subtopic: Réseaux informatiques

The rapid growth of the data traffic demands new ways to achieve high-speed wireless links. The backbone networks, data centers, mission-critical applications, as well as end-users sitting in office or home, all require ultra-high throughput and ultra-low latency wireless links. Sophisticated technological advancement and huge bandwidth are required to reduce the latency. Terahertz band, in this regard, has a huge potential to provide these high-capacity links where a user can download the file in a few seconds.

To realize the high-capacity wireless links for future applications, in this book, different aspects of the Terahertz band wireless communication network are presented. This book highlights the Terahertz channel characteristics and modeling, antenna design and beamforming, device characterization, applications, and protocols. It also provides state-of-the-art knowledge on different communication aspects of Terahertz communication and techniques to realize the true potential of the Terahertz band for wireless communication.

Chapter 1

The Meeting Point of Terahertz Communications, Sensing, and Localization

Hadi Sarieddeen, Nasir Saeed, Tareq Y. Al-Naffouri, and Mohamed-Slim Alouini

Contents

1.1Introduction

1.2THz Communications

1.2.1Use Cases for THz Communications

1.2.2Challenges and Solutions

1.2.3A Model of the THz Communications System

1.3THz Sensing and Imaging

1.4THz Localization

1.4.1Time of Arrival Ranging

1.4.2Time Difference of Arrival (TDoA) Ranging

1.4.3Received Signal Strength (RSS) Ranging

1.4.4Angle of Arrival (AoA) Ranging

1.4.5Localization Using THz signals

1.5Implementation Aspects

1.6Conclusion

1.1 Introduction

As the demand for bandwidth continues to increase, wireless communication carrier frequencies continue to expand. Recently, efficient communication paradigms have been demonstrated at the millimeter (mmWave) band [1,2], as well as at the optical band in free space optics (FSO) and visible light communications (VLC) [3,4]. In between, the terahertz (THz) band stands as an unexamined part of the radio frequency (RF) spectrum. RF engineers mark any system operating beyond 100 GHz as a THz system, below which popular mmWave applications are placed. On the other hand, optical engineers observe all frequencies beneath the far-infrared (10 THz threshold) as THz frequencies. Nevertheless, as defined by IEEE Transactions on Terahertz Science and Technology, the THz band ranges between 300 GHz and 10 THz.

Today, researchers are exploring technologies from both neighboring bands to advance THz communications and close the so-called THz gap that existed because of the absence of efficient and compact THz devices. Contemporary THz transceiver design research is employed mostly in electronics and photonics [5–8]. Even though a significant data rate gain is observed in photonic technologies, electronic solutions continue to be superior in generating higher power. Electronic solutions [5] are principally based on silicon complementary metal-oxide-semiconductor (CMOS) technology, high electron mobility transistors (HEMTs), and III–V-based semiconductors in heterojunction bipolar transistors (HBTs). Photonic solutions [6], on the other hand, are based on photoconductive antennas, uni-traveling carrier photodiodes, quantum cascade lasers, and optical down-conversion systems. Besides, integrated hybrid electronic-photonic solutions [7] are gaining popularity as they can achieve a good trade-off between reconfigurability and performance. Similarly, plasmonic solutions based on novel materials are emerging, graphene-based solutions [9], in particular.

Traditional THz-band use cases have been in imaging and sensing [10–14]. Recently, the progress in signal generation and modulation techniques at the THz band is paving the way toward THz communication-based use cases [15–20]. THz communications promise to enable ultra-low latency and ultra-high bandwidth communication schemes, to support mobile wireless medium-range communications at both the access and device levels in the context of indoor and outdoor communications (Figure 1.1). By merging THz communications, sensing, imaging, and localization, THz technology can realize 6G ubiquitous wireless intelligence [21–23]. This chapter advocates the merging of these applications by detailing the corresponding system models and illustrating proof-of-concept results.

Figure 1.1Prospective outdoor and indoor THz-band applications in communications and sensing.

1.2 THz Communications

1.2.1 Use Cases for THz Communications

THz communications are expected to be realized in the future sixth-generation (6G) of wireless mobile communications [24–27] and beyond, enabling ultra-low latency and ultra-high bandwidth communication models. Consequently, several research groups have drawn substantial funds to carry THz research, and standardization attempts have started [28–30]. THz communications promise a terabit/second data rate, which opens the door for applications that cannot be accomplished in mmWave systems. Compared to mmWave communications, THz communications sustain higher directionality, maintain greater resilience to eavesdropping, and are less sensitive to inter-antenna interference and free-space diffraction. This is mainly due to the inherently shorter wavelengths at THz frequencies, further resulting in THz systems being realized in much smaller footprints. Furthermore, as opposed to VLC/FSO, THz signals are less influenced by factors such as cloud dust, scintillation, ambient light, atmospheric turbulence, and others. Nevertheless, by simultaneously using mmWave, THz, and optical communications in a heterogeneous plan, availability can be enhanced.

In a particular use case, THz-band communications can enhance future vehicular networks, both in terms of reliability and latency [31]. Reliable and high-speed communications are critical demands of future vehicular networks, where the bird’s-eye view for a vehicle necessitates 50 ms latency and 50 Mbps data rate [32]. Correspondingly, automatic over-take requires less than 10 ms latency for 99.999% reliability. Therefore, researchers envision that using the THz band will improve safety solutions and enable various other applications such as remote driving and vehicle platooning.

In another plausible use case, the THz band can accommodate high-speed communications among drones. Recently, flying ad-hoc networks (FANETs) consisting of several drones have ...