2 research outputs found
Towards efficient support for massive Internet of Things over cellular networks
The usage of Internet of Things (IoT) devices over cellular networks is seeing tremendous
growth in recent years, and that growth in only expected to increase in the near
future. While existing 4G and 5G cellular networks offer several desirable features for
this type of applications, their design has historically focused on accommodating traditional
mobile devices (e.g. smartphones). As IoT devices have very different characteristics
and use cases, they create a range of problems to current networks which often
struggle to accommodate them at scale. Although newer cellular network technologies,
such as Narrowband-IoT (NB-IoT), were designed to focus on the IoT characteristics,
they were extensively based on 4G and 5G networks to preserve interoperability, and
decrease their deployment cost. As such, several inefficiencies of 4G/5G were also
carried over to the newer technologies.
This thesis focuses on identifying the core issues that hinder the large scale deployment
of IoT over cellular networks, and proposes novel protocols to largely alleviate
them. We find that the most significant challenges arise mainly in three distinct areas:
connection establishment, network resource utilisation and device energy efficiency.
Specifically, we make the following contributions. First, we focus on the connection
establishment process and argue that the current procedures, when used by IoT devices,
result in increased numbers of collisions, network outages and a signalling overhead
that is disproportionate to the size of the data transmitted, and the connection duration
of IoT devices. Therefore, we propose two mechanisms to alleviate these inefficiencies.
Our first mechanism, named ASPIS, focuses on both the number of collisions
and the signalling overhead simultaneously, and provides enhancements to increase the
number of successful IoT connections, without disrupting existing background traffic.
Our second mechanism focuses specifically on the collisions at the connection establishment
process, and used a novel approach with Reinforcement Learning, to decrease
their number and allow a larger number of IoT devices to access the network with fewer
attempts.
Second, we propose a new multicasting mechanism to reduce network resource
utilisation in NB-IoT networks, by delivering common content (e.g. firmware updates)
to multiple similar devices simultaneously. Notably, our mechanism is both more efficient
during multicast data transmission, but also frees up resources that would otherwise
be perpetually reserved for multicast signalling under the existing scheme.
Finally, we focus on energy efficiency and propose novel protocols that are designed
for the unique usage characteristics of NB-IoT devices, in order to reduce the
device power consumption. Towards this end, we perform a detailed energy consumption
analysis, which we use as a basis to develop an energy consumption model for
realistic energy consumption assessment. We then take the insights from our analysis,
and propose optimisations to significantly reduce the energy consumption of IoT
devices, and assess their performance
Potentzia domeinuko NOMA 5G sareetarako eta haratago
Tesis inglés 268 p. -- Tesis euskera 274 p.During the last decade, the amount of data carried over wireless networks has grown exponentially. Several reasons have led to this situation, but the most influential ones are the massive deployment of devices connected to the network and the constant evolution in the services offered. In this context, 5G targets the correct implementation of every application integrated into the use cases. Nevertheless, the biggest challenge to make ITU-R defined cases (eMBB, URLLC and mMTC) a reality is the improvement in spectral efficiency. Therefore, in this thesis, a combination of two mechanisms is proposed to improve spectral efficiency: Non-Orthogonal Multiple Access (NOMA) techniques and Radio Resource Management (RRM) schemes. Specifically, NOMA transmits simultaneously several layered data flows so that the whole bandwidth is used throughout the entire time to deliver more than one service simultaneously. Then, RRM schemes provide efficient management and distribution of radio resources among network users. Although NOMA techniques and RRM schemes can be very advantageous in all use cases, this thesis focuses on making contributions in eMBB and URLLC environments and proposing solutions to communications that are expected to be relevant in 6G