THESIS
2020
xx, 100 pages : illustrations ; 30 cm
Abstract
With the development of wireless communication technologies, an increasing
number of sensor nodes can be accommodated in a wireless sensor network
(WSN). To evaluate the performance of a large-scale networked system and
efficiently exploit the channel resources, it is necessary to employ an accurate
and computationally efficient model for a dense network.
This thesis investigates competition for channel resources in wireless communication
with a mean-field type game model, which addresses large-scale
interactions among a non-cooperative player population with low complexity.
Both performance comparison between different generations of multiple access
protocols and optimal design of a channel allocation mechanism for accommodating
data sources have been investigated.
We first...[
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With the development of wireless communication technologies, an increasing
number of sensor nodes can be accommodated in a wireless sensor network
(WSN). To evaluate the performance of a large-scale networked system and
efficiently exploit the channel resources, it is necessary to employ an accurate
and computationally efficient model for a dense network.
This thesis investigates competition for channel resources in wireless communication
with a mean-field type game model, which addresses large-scale
interactions among a non-cooperative player population with low complexity.
Both performance comparison between different generations of multiple access
protocols and optimal design of a channel allocation mechanism for accommodating
data sources have been investigated.
We first consider a competition in transmission power control over a shared
uplink channel. We propose a framework of a massive transmission power contest
in a dense network with a mean-field limit model. The CDMA protocol, as
a supporting technology of 3G networks accommodating signal from different
sources over the code domain, represents the orthogonal multiple access (OMA)
techniques. With the development of 5G wireless networks, non-orthogonal multiple
access (NOMA) has been introduced to improve the efficiency of channel
allocation.
Our goal is to investigate whether the power-domain NOMA protocol can
regulate the non-cooperative channel access behaviors, i.e., steering the competition
among the non-cooperative users in a direction with improved efficiency
and fairness. It is compared with the CDMA protocol, which drives each user
to compete fiercely against the population, hence sacrificing the efficiency of
channel usage. The existence and uniqueness of an equilibrium strategy under
CDMA and NOMA is characterized. Subsequently, we adopt the social welfare
of the population as the performance metric, which is defined as the expectation
of utility over the distribution of users with different channel gains. It
is shown that under equilibrium strategies, NOMA outperforms CDMA in the
social welfare achieved, which is also illustrated through simulation. Moreover,
it is observed from numerical results that NOMA can improve the fairness of
the achieved data rates among different users.
As efficiency is often sacrificed when resources are allocated through competition,
another goal of this thesis is to consider, from the perspective of the base
station, how to regulate the behaviors among channel users to achieve better
social welfare when the equilibrium is reached in a large user population. We
consider a mechanism design formulation of resource allocation, where the channel
resources are allocated to the users by auction. The base station takes bids
from all channel users and allocates channel capacity accordingly, which induces
"payments" from the users to the base station in terms of transmission power.
We identify the structure of the optimal mechanism for accommodating a large
user population with the CDMA protocol. The optimal mechanism design for
NOMA remains a direction of future work.
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