Random access control schemes for massive machine type communications in cellular IOT networks
Machine Type Communications (MTC) refer to the autonomous interaction between connected devices without human intervention. The deployment of MTC on cellular networks provides ubiquitous services to Internet-of-Things (IoT) systems. Recently, the Third-Generation Partnership Project (3GPP) introd...
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| Format: | Thesis |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/104005/1/ALTHUMALI%2C%20HUDA%20DAKHILALLAH%20A%20-%20IR.pdf http://psasir.upm.edu.my/id/eprint/104005/ |
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| Summary: | Machine Type Communications (MTC) refer to the autonomous interaction between
connected devices without human intervention. The deployment of MTC
on cellular networks provides ubiquitous services to Internet-of-Things (IoT)
systems. Recently, the Third-Generation Partnership Project (3GPP) introduced
the standard specifications of deploying MTC on cellular networks. The 3GPP
recommends the recent cellular networks such as Long-Term Evolution (LTE),
LTE-Advanced (LTE-A) and Fifth-Generation (5G) networks as an appropriate
infrastructure for MTC due to wide coverage, scalability, low latency and
spectral efficiency.
Indeed, with an increased number of devices connecting to the network everyday,
massive numbers of machine devices are expected to simultaneously access
the network resources especially during emergency scenarios. This massive
access results in excessive congestion and collisions in the random access
channel (RACH) which is considered the first step to access network resources.
These massive collisions cause the devices to be blocked from accessing network
resources which results in performance degradation for the overall MTC
system. For this reason, it is important to improve random access (RA) control
schemes to accommodate the increased number of machine devices connecting
to the network. In this thesis, RA control schemes are classified according to
targetted objectives into three categories: (1) massive access control schemes,
(2) energy efficiency schemes and (3) performance improvement schemes. Each
category is further divided into two subcategories, and the relevant RA schemes
are presented for each category. Furthermore, an analytical comparison has
been provided among the different schemes according to several performance
parameters. This work mainly focuses on the massive access control schemes
which are sub-divided into congestion control and collision resolution schemes.
In order to increase the access success rate during massive access scenarios,
this work proposes a new dynamic backoff collision resolution scheme (DBCR)
for delay-tolerant devices. In this scheme, the RACH collisions are resolved
using a backoff procedure which dynamically adjusts the backoff indicator
(BI) based on the number of backlog devices and available resources. The
proposed scheme is integrated with three well-known random access schemes.
The mathematical analysis of the DBCR and derivation of the optimal value
of BI is presented for the three different combinations. Thereafter, extensive
simulations are performed to evaluate the proposed scheme. The analysis
and simulation results demonstrate that the DBCR scheme achieves an access
success rate of 99.9% with a slight increase in access delay which is reasonable
for delay-tolerant applications during massive arrivals scenarios.
Further, this work introduces a dynamic tree splitting (DTS) scheme to resolve
RACH collisions for delay-sensitive devices during burst arrival scenarios. The
DTS scheme assigns a specific number of resources/preambles to the collided
group of devices for their next access attempt with the aim of reducing access
delay. The number of preambles assigned for each group is determined based
on the mean number of collisions in each random access opportunity (RAO) in
order to increase the utilisation of preambles. The mathematical analysis of the
proposed scheme is presented and the access delay is derived. The analysis and
simulation results show that the DTS reduces the access delay by approximately
12% compared to the recent benchmarks, with a very low drop rate, which
indicates the efficiency and reliability of the proposed scheme.
Furthermore, a priority-based load-adaptive preambles separation (PLPS) RA
scheme for quality-of-service (QoS)-differentiated applications in 5G networks is
proposed. In this scheme, three classes of devices are considered. These are devices
with enhanced mobile broadband (eMBB), ultra-reliable low latency communication
(URLLC) and massive machine type communication (mMTC). The
available number of preambles is divided into three groups, and the number of
preambles is assigned for each group based on class priority and load intensity.
The mathematical analysis of the proposed scheme is presented along with the
derivations of several performance metrics. The analysis and simulation results
show that the PLPS scheme succeeds in achieving the targetted QoS requirements
for each class even for a large number of devices, which is very promising
for the 5G heterogeneous services. |
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