Strengthening real-time support in wireless networks
Citation:
Mark Gleeson, 'Strengthening real-time support in wireless networks', [thesis], Trinity College (Dublin, Ireland). School of Computer Science & Statistics, 2010, pp 231Download Item:
Gleeson, Mark_TCD-SCSS-PHD-2010-09.pdf (PDF) 2.445Mb
Abstract:
Wireless networks exhibit unpredictable and varying connection reliability as a result
of node mobility and resultant changes in wireless signal propagation. Wireless signal
propagation not only depends on the receiver’s mobility but also on unrelated objects
both mobile and fixed in the environment. In such dynamic and unknown environments,
the provision of real-time communication represents a significant challenge. Not only
must transmissions be managed to avoid collisions but may also need to be rescheduled in
response to communication failures to ensure success retransmission of frames following
failures.
Previous work in this area has considered the support for real-time communication
with significant constraints, by either relying on master/slave network architectures or
through approri knowledge of the network structure. These approaches focus on the
creation of collision-free transmission schedules determined off-line, distributed before
the execution of the system or through a centralised contention-based resource allocation
approach.
In this thesis, the need to provide real-time support in a wireless environment in
the absence of a master node is discussed. In light of varying communication and node
reliability, a distributed solution is chosen to provide resilience in the presence of failures.
Unlike other TDMA protocols, the impact of communication-related failures in the
form of burst-and single-bit errors is addressed. The protocol reacts to overcome burst
errors where possible by exploiting the statistical independence of communication bevi
tween individual wireless nodes in conjunction with dynamic rescheduling in response to
communication errors to enhance real-time support in the wireless domain.
Transmission reliability is addressed through an admissions control process based
on clustering transmission resources of destinations with similar transmission probabilities
through the application of binomial distribution. This process estimates the overall
number of transmissions required to meet the real-time requirements of frames. The application
of the clustering algorithm reduces the total number of transmissions required.
This thesis makes two key contributions: Firstly, a medium access control protocol,
Hierarchical Distributed Time Division Multiple Access (HD-TDMA), is proposed, which
incorporates in its design flexibility to permit multiple transmissions per TDMA slot.
Secondly, a local, autonomous decision making process exploits the flexibility of HDTDMA
to schedule packets to meet real-time requirements while incorporating the ability
to dynamically reschedule packets to overcome burst error conditions while, attempting
to maintain real-time deadlines.
Author: Gleeson, Mark
Advisor:
Weber, StefanQualification name:
Doctor of Philosophy (Ph.D.)Publisher:
Trinity College (Dublin, Ireland). School of Computer Science & StatisticsNote:
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