2 research outputs found
Congestion Control for Machine-Type Communications in LTE-A Networks
Collecting data from a tremendous amount of Internet-of-Things (IoT) devices for next generation networks is a big challenge. A large number of devices may lead to severe congestion in Radio Access Network (RAN) and Core Network (CN). 3GPP has specified several mechanisms to handle the congestion caused by massive amounts of devices. However, detailed settings and strategies of them are not defined in the standards and are left for operators. In this paper, we propose two congestion control algorithms which efficiently reduce the congestion. Simulation results demonstrate that the proposed algorithms can achieve 20~40% improvement regarding accept ratio, overload degree and waiting time compared with those in LTE-A
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