Abstract—In this paper, we propose and analyze a different
channel allocation scheme in mobile cellular networks which not
only gives priority to handoff calls but also tries to protect
originating calls. We use channel reservation to protect handoff
calls and in contrast, to protect originating calls, we set a
maximum reservable channel, NG, in our scheme. In channel
reservation schemes, there are some periods that reserved
channels are not actively utilized. In this paper, these periods are
defined as dead time. Some new performance measures of the
system such as the distribution and the mean dead time of a
reserved channel are obtained. The main contribution of this
work is to find optimum NG so as to maximize the service
provider's revenue while customers' satisfaction (in term of
connection continuity) and system utilization (in term of system
capacity and less dead time) are justified jointly. We assume a
general cost structure which is due to blocking of handoff calls,
blocking of originating calls and unutilized periods of reserved
channels. Based on the total cost, we investigate the trade-off
between the service utilization and customers' satisfaction.
Keywords: Resource management, revenue schemes, wireless
communication systems, performance modeling.
I. INTRODUCTION
Technological advances and rapid development of
handheld wireless terminals have facilitated the rapid growth
of wireless communications. Taking ergonomic and economic
factors into account, and considering the new trend in
telecommunications industry to provide ubiquitous
information access, the population of mobile users will
continue to grow at a tremendous rate, while customers are
expecting the same quality of service (QoS)
1
, availability and
performance as the traditional wire-line networks. To cope
with this challenge, many new modulation and multiple access
techniques have been developed. But for a given spectrum and
a specific technology used, the admitted traffic capacity and
QoS of a cellular system depends on how channels are
managed. Since from the subscriber’s view point, forced
1
We limit the QoS discussion to the issues of call dropping and connection
continuity in order to minimize the dimensionality of the problem.
termination due to handover calls is more annoying than
blocking of a new call, therefore, protecting the connection
continuity for mobile users, as a QoS constraint, has been
studied extensively. Basic techniques to this protection are
guard channel (GC) [1], handoff queuing [2], [3], and
predictive channel reservation (PCR) [4], [5]. Other
techniques for handoff protection include subrating [6],
channel sharing [7], and channel carrying [8]. Indeed, the final
goal of these schemes is to increase the connection continuity
for an admitted call [9].
It has been declared in [9] that all of the three priority-
based handoff protection schemes that are discussed
frequently in the literature - GC, handoff queuing, and PCR -
result in decreased handover failures but increased new call
blocking. In other words, system capacity and QoS are two
conflicting objectives and tradeoff is inevitable.
Some researchers have investigated the possibility of
minimizing new call blocking while providing handoff
protection. In [10], Oh and Tcha have proposed careful
division of nominal channels into guard and nonguard sets so
that handoff failure is reduced within the constraint of
satisfying a predefined grade of service. Minor changes such
as adding or removing one guarded channel affect the new
user admission and handoff protection performance
significantly. Therefore, the use of fractional guard channel
[11] permits fine adjustment by setting aside a noninteger
number of guarded channels. The dynamic channel allocation
scheme in [12] permits guarded channels to be provisionally
accessed by new users if the number of handoff requests is
small. In [13], channels in each cell are divided into two parts.
To increase the channel utilization while maintaining QoS of
each type for traffic, handoff calls are allowed to borrow
channels from the other under certain constraints.
In this paper, we propose and analyze a different handoff
scheme which not only gives priority to handoff calls, due to
importance of them from QoS standpoint, but also protects
originating calls. The scheme is a composition of GC and
PCR. In order to make prioritization on handoff calls, we use
PCR technique and in contrast, to protect originating calls, we
set an upper limit on reserved channels, denoted in this paper
by NG. It is obvious that increasing the upper limit on
reserved channels protects handoff calls better and in contrast
Channel Management Based on Maximizing
Customers' Satisfaction and Service Providers'
Revenue
S. Ali. A. Fakoorian, Hassan Taheri and Mohammad Fathi
Department of Electrical Engineering
Amirkabir University of Technology, Tehran, Iran
fakoorian@ieee.org htaheri@aut.ac.ir
702
978-1-4244-1653-0/08/$25.00 ©2008 IEEE
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