Muhammad Sohaib Amjad
Towards Low Latency and Bandwidth Efficient
Communication in Wireless Systems
Dissertation
05 May 2021
Please cite as:
Muhammad Sohaib Amjad, “Towards Low Latency and Bandwidth Efficient Communication in Wireless Systems,” PhD
Thesis (Dissertation), Institute of Telecommunication Systems, Technische Universität Berlin, Germany, June 2021.
Fachgebiet Telekommunikationsnetze
Technische Universität Berlin, Germany
Einsteinufer 25 ·10587 Berlin ·Germany
https://www.tkn.tu-berlin.de/
Towards Low Latency and Bandwidth
Efficient Communication in Wireless Systems
vorgelegt von
M.Sc.
Muhammad Sohaib Amjad
an der Fakultät IV – Elektrotechnik und Informatik
der Technischen Universität Berlin
zur Erlangung des akademischen Grades
Doktor der Ingenieurwissenschaften
– Dr.-Ing. –
genehmigte Dissertation
Vorsitzender: Prof. Dr.-Ing. habil. Falko Dressler
Gutachter: Prof. Dr.-Ing. habil. Falko Dressler
Prof. Dr.-Ing. Dr.-Ing. habil. Robert Weigel
Prof. Dr. Hsin-Mu (Michael) Tsai
Tag der wissenschaftlichen Aussprache: 05. Mai 2021
Berlin 2021
Abstract
The densely utilized sub-
6 GHz
spectrum is reaching critical saturation levels due to
the growing number of wirelessly connected devices and their increasing demand for
high-speed real-time content access. The ubiquitous connectivity and high data rates
in the existing wireless architecture are, therefore, struggling, with both limited
link-capacity and channel access. In this regard, infrastructure relays have also
been considered for maintaining high-speed wireless connectivity and improved user
experience. Nevertheless, due to the existing relaying structure’s half-duplex nature,
higher latencies are typically experienced, especially in multi-hop scenarios.
To address this issue, in-band Full-Duplex Relaying (FDR) has been proposed in
the literature, which is still missing standardized implementations for experimenta-
tion and evaluation purposes. The first part of the thesis fills this gap and presents
an IEEE 802.11 a/g/p compliant FDR implementation in the GNU Radio framework.
We first evaluate FDRs’ performance in a dual-hop scenario, with simulations and
Software-Defined Radio (SDR)-based real-world experiments. We further consider
FDR applicability in vehicular platooning and study its potential in sub-
6 GHz
and
77 GHz
mmWave channels. Our results show that FDR substantially reduces the
physical layer latency and transmission power requirements in a multi-hop system,
provided that the looped self-interference is sufficiently suppressed.
The second part of this thesis explores the spectrum beyond conventional RF for
communications and investigate Visible Light Communication (VLC) as an access
technology for bandwidth-efficient and low latency communications. We first present
a flexible IEEE 802.11 compliant Vehicular-VLC (V-VLC) system, which utilizes com-
mercial off-the-shelf hardware. Our real-time experiments in the outdoors during the
daytime confirm that our system prevents the strong impact of daylight and demon-
strates reliable communications for distances beyond
75 m
, regardless of the time
of the day. We then propose a novel indoor visible light-based communication and
non-invasive sensing system with applications in industrial automation and Internet
of Things (IoT) solutions. Our results show that integrating the two technologies
only marginally lowers individual performance; however, the combined system is
especially beneficial in radio-hostile and hazardous industrial environments.
iii
Loading more pages...