Abstract
The paper explores delay-based congestion and flow
control and the offloading of real-time traffic from
wireless local area networks (WLANs) to mobile cellular
networks (MCNs) in multihomed devices. The control system
developed is based on an embedded hierarchical expert
system. It adjusts transceivers' traffic flow(s) for
prevailing network conditions to achieve
application-dependent delay and throughput limits. In
wireless networks, delay and throughput depend on the
packet size, packet transmission interval, and node
connection density. Therefore, the controller on the
destination node monitors average one-way delay and the
change of one-way delay of the incoming traffic. On this
basis, it adjusts the packet size and transmission
interval of the source node by transmitting a control
command to the source. If the prevailing level of traffic
in the network exceeds its capacity despite of the
control actions taken, devices prepare for developed
asynchronous offloading of traffic to another access
network. The control model was validated via simulation
of Voice over Internet Protocol (VoIP) traffic in the
OMNeT++ network simulator. The results demonstrate that
the expert system developed is able to regulate packet
sizes to match the prevailing application-dependent
optimum and transfer traffic to another network if the
network exceed its capacity no matter the control actions
taken. Although this work is motivated mainly by issues
of congestion and flow control of WLAN systems and the
simulations and results were prepared for the IEEE
802.11b system, the approach and techniques are not
limited to these systems, but they are applicable for
other packet switched access networks (PSANs), too
Original language | English |
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Pages (from-to) | 4996-5008 |
Journal | Expert Systems with Applications |
Volume | 41 |
Issue number | 10 |
DOIs | |
Publication status | Published - 2014 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Expert system
- flow control
- fuzzy control
- offloading
- real-time traffic
- WLAN