11,779 research outputs found
On the Stability of a Polling System with an Adaptive Service Mechanism
We consider a single-server cyclic polling system with three queues where the
server follows an adaptive rule: if it finds one of queues empty in a given
cycle, it decides not to visit that queue in the next cycle. In the case of
limited service policies, we prove stability and instability results under some
conditions which are sufficient but not necessary, in general. Then we discuss
open problems with identifying the exact stability region for models with
limited service disciplines: we conjecture that a necessary and sufficient
condition for the stability may depend on the whole distributions of the
primitive sequences, and illustrate that by examples. We conclude the paper
with a section on the stability analysis of a polling system with either gated
or exhaustive service disciplines.Comment: 16 page
Random Fluid Limit of an Overloaded Polling Model
In the present paper, we study the evolution of an overloaded cyclic polling
model that starts empty. Exploiting a connection with multitype branching
processes, we derive fluid asymptotics for the joint queue length process.
Under passage to the fluid dynamics, the server switches between the queues
infinitely many times in any finite time interval causing frequent oscillatory
behavior of the fluid limit in the neighborhood of zero. Moreover, the fluid
limit is random. Additionally, we suggest a method that establishes finiteness
of moments of the busy period in an M/G/1 queue.Comment: 36 pages, 2 picture
Providing Delay Guarantees in Bluetooth
Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network. In this paper we present a polling mechanism that provides delay guarantees in an efficient manner and we evaluate this polling mechanism by means of simulation. It is shown that this polling mechanism is able to provide delay guarantees while saving as much as possible resources, which can be used for transmission of best effort traffic or for retransmission
A polling system whose stability region depends on a whole distribution of service times
We present an example of a single-server polling system with two queues and
an adaptive service policy where the stability region depends on the expected
values of all the primitives and also on a certain exponential moment of the
service-time distribution in one of the queues. The latter parameter can not be
determined, in general, in terms of any finite number of power moments. It
follows that the fluid approximation approach may not be an appropriate tool
for the stability study of this model.Comment: 6 page
Upstream traffic capacity of a WDM EPON under online GATE-driven scheduling
Passive optical networks are increasingly used for access to the Internet and
it is important to understand the performance of future long-reach,
multi-channel variants. In this paper we discuss requirements on the dynamic
bandwidth allocation (DBA) algorithm used to manage the upstream resource in a
WDM EPON and propose a simple novel DBA algorithm that is considerably more
efficient than classical approaches. We demonstrate that the algorithm emulates
a multi-server polling system and derive capacity formulas that are valid for
general traffic processes. We evaluate delay performance by simulation
demonstrating the superiority of the proposed scheduler. The proposed scheduler
offers considerable flexibility and is particularly efficient in long-reach
access networks where propagation times are high
Large deviations for polling systems
Related INRIA Research report available at : http://hal.inria.fr/docs/00/07/27/62/PDF/RR-3892.pdfInternational audienceWe aim at presenting in short the technical report, which states a sample path large deviation principle for a resealed process n-1 Qnt, where Qt represents the joint number of clients at time t in a single server 1-limited polling system with Markovian routing. The main goal is to identify the rate function. A so-called empirical generator is introduced, which consists of Q t and of two empirical measures associated with S t the position of the server at time t. The analysis relies on a suitable change of measure and on a representation of fluid limits for polling systems. Finally, the rate function is solution of a meaningful convex program
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