Results 1  10
of
20
A generalized processor sharing approach to flow control in integrated services networks: The singlenode case
 IEEE/ACM Transactions on Networking
, 1993
"... AbstruetThe problem of allocating network resources to the users of an integrated services network is investigated in the context of ratebased flow control. The network is assumed to be a virtual circuiq comectionbased packet network. We show that the use of Generalized processor Sharing (GPS), w ..."
Abstract

Cited by 1676 (4 self)
 Add to MetaCart
AbstruetThe problem of allocating network resources to the users of an integrated services network is investigated in the context of ratebased flow control. The network is assumed to be a virtual circuiq comectionbased packet network. We show that the use of Generalized processor Sharing (GPS), when combined with Leaky Bucket admission control, allows the network to make a wide range of worstcase performance guarantees on throughput and delay. The scheme is flexible in that d~erent users may be given widely different performance guarantees, and is efilcient in that each of the servers is work conserving. We present a practicat packetbypacket service discipline, PGPS (first proposed by Deme5 Shenker, and Keshav [7] under the name of Weighted Fair Queueing), that closely approximates GPS. This altows us to relate ressdta for GPS to the packetbypacket scheme in a precise manner. In this paper, the performance of a singleserver GPS system is analyzed exactty from the standpoint of worstcase packet delay and burstiness when the sources are constrained by leaky buckets. The worstcase sewdon backlogs are also determined. In the sequel to this paper, these results are extended to arbitrary topology networks with multiple nodes. I.
Computing distributions and moments in polling models by numerical transform inversion
 Eval
, 1996
"... We show that probability distributions and moments of performance measures in many polling models can be effectively computed by numerically inverting transforms (generating functions and Laplace transforms). We develop new efficient iterative algorithms for computing the transform values and then u ..."
Abstract

Cited by 13 (6 self)
 Add to MetaCart
We show that probability distributions and moments of performance measures in many polling models can be effectively computed by numerically inverting transforms (generating functions and Laplace transforms). We develop new efficient iterative algorithms for computing the transform values and then use our recently developed variant of the Fourierseries method to perform the inversion. We also show how to use this approach to compute moments and asymptotic parameters of the distributions. We compute a twoterm asymptotic expansion of the tail probabilities, which turns out to be remarkably accurate for small tail probabilities. The tail probabilities are especially helpful in understanding the performance of different polling disciplines. For instance, it is known that the exhaustive discipline produces smaller mean steadystate waiting times than the gated discipline, but we show that the reverse tends to be true for small tail probabilities. The algorithms apply to describe the transient behavior of stationary or nonstationary models as well as the steadystate behavior of stationary models. We demonstrate effectiveness by analyzing the computational complexity and by doing several numerical examples for the gated and exhaustive service disciplines, with both zero and nonzero switchover times. We also show that our approach applies to other polling models. Our main focus is on computing exact tail probabilities and asymptotic approximations to them, which seems not to have been done before. However, even for mean waiting times, our algorithm is faster than previous algorithms for large models. The computational complexity of our algorithm is O(N α) for computing performance measures at one queue and O(N 1 + α) for computing performance measures at all queues, where N is the number of queues and α is typically between 0.6 and 0.8.
Analysis of Alternatingpriority Queueing Models with (Cross) Correlated Switchover Times
, 2005
"... This paper analyzes a single server queueing system in which service is alternated between two queues and the server requires a (finite) switchover time to switch from one queue to the other. The distinction from classical results is that the sequence of switchover times from each of the queues need ..."
Abstract

Cited by 3 (1 self)
 Add to MetaCart
This paper analyzes a single server queueing system in which service is alternated between two queues and the server requires a (finite) switchover time to switch from one queue to the other. The distinction from classical results is that the sequence of switchover times from each of the queues need not be i.i.d. nor independent from each other; each sequence is merely required to form a stationary ergodic sequence. With the help of stochastic recursive equations explicit expressions are derived for a number of performance measures, most notably for the average delay of a customer and the average queue lengths under different service disciplines. With these expressions a comparison is made between the service disciplines and the influence of correlation is studied. Finally, through a number of examples it is shown that the correlation can significantly increase the mean delay and the average queue lengths indicating that the correlation between switchover times should not be ignored. This has important implications for communication systems in which a common communication channel is shared amongst various users and where the time between consecutive data transfers is correlated (for example in adhoc networks).
Q²: A New Performance Analysis Tool Exploiting Numerical Transform Inversion
 PROC. IEEE MASCOTS ‘95
, 1995
"... We describe a new tool that we are developing to help analyze the performance of emerging telecommunication systems. These emerging systems include ATM, broadband, intelligent and wireless networks, each of which will support a wide variety of services and media. Our tool is distinguished from previ ..."
Abstract

Cited by 3 (2 self)
 Add to MetaCart
We describe a new tool that we are developing to help analyze the performance of emerging telecommunication systems. These emerging systems include ATM, broadband, intelligent and wireless networks, each of which will support a wide variety of services and media. Our tool is distinguished from previous tools by exploiting numerical transform inversion. In this paper we describe three modules in the tool. These modules provide algorithms for obtaining the exact analytic solutions to: (i) resourcesharing models, (ii) BMAP/G/1 queueing models and (iii) polling models. Since the tool is based on analytical methods instead of simulation, it is relatively fast. The tool has a windowbased menudriven interface and provides both graphical and numerical output.
Cyclic Bernoulli Polling
 ZOR Methods and Models of Operations Research
, 1993
"... Abstract: We introduce, analyse and optimize the class of Bernoulli random polling systems. The server moves cyclically among N channels (queues), but Changeover times between stations are composed of walking times required to 'move ' from one channel to another and switchin times that a ..."
Abstract

Cited by 2 (1 self)
 Add to MetaCart
Abstract: We introduce, analyse and optimize the class of Bernoulli random polling systems. The server moves cyclically among N channels (queues), but Changeover times between stations are composed of walking times required to 'move ' from one channel to another and switchin times that are incurred only when the server actually enters a station to render service. The server uses a Bernoulli random mechanism to decide whether to serve a queue or not: upon arrival to channel i, it switches in with probability Pi, or moves on to the next queue (w.p. 1 pl) without serving any customer (e.g. packet or job). The Cyclic Bernoulli Polling (CBP) scheme is independent of the service regime in any particular station, and may be applied to any service discipline. In this paper we analyse three different service disciplines under the CBP scheme: Gated, Partially Exhaustive and Fully Exhaustive. For each regime we derive expressions for (i) the generating functions and moments of the number of customers (jobs) at the various queues at polling instants, (ii) the expected number of jobs that an arbitrary departing job leaves behind it, and (iii) the LST and expectation of the waiting time of a cutomer at any given queue. The fact that these measures of performance can be explicitly obtained under the CBP is an advantage over all "parameterized " cyclic polling schemes (such as the klimited discipline) that have been studied in the literature, and for which explicit
Analysis of a Polling System for Telephony Traffic with Application to Wireless LANs
, 2006
"... Recently, polling has been included as a resource sharing mechanism in the Medium Access Control (MAC) protocol of several communication systems, such as the IEEE 802.11 wireless local area network, primarily to support realtime traffic. Furthermore, to allow these communication systems to support ..."
Abstract

Cited by 2 (1 self)
 Add to MetaCart
Recently, polling has been included as a resource sharing mechanism in the Medium Access Control (MAC) protocol of several communication systems, such as the IEEE 802.11 wireless local area network, primarily to support realtime traffic. Furthermore, to allow these communication systems to support multimedia traffic, the polling scheme often coexists with other MAC schemes such as random access. Motivated by these systems, we develop a model for a polling system with vacations, where the vacations represent the time periods in which the resource sharing mechanism used is a nonpolling mode. The realtime traffic served by the polling mode in our study is telephony. We use an ONOFF Markov Modulated Fluid (MMF) model to characterize telephony sources. Our analytical study and a counterpart validating simulation study show the following. Since voice codec rates are much smaller than link transmission rates, the queueing delay that arises from waiting for a poll dominates the total delay experienced by a voice packet. To keep delays low, the number of telephone calls that can be admitted must be chosen carefully according to delay tolerance, loss tolerance, codec rates, protocol overheads and the amount of bandwidth allocated to the polling mode. The effect of statistical multiplexing gain obtained by exploiting the ONOFF characteristics of telephony traffic is more noticeable when the impact of polling overhead is small.
Performance Analysis of a Dual Round Robin Matching Switch with Exhaustive Service
 IN PROC. IEEE HIGHSPEED NETWORKING WORKSHOP 2002. JUNE 23, 2002
, 2002
"... Virtual Output Queuing is widely used by fixedlength highspeed switches to overcome headofline blocking. This is done by means of matching algorithms. Maximum matching algorithms have good performance, but their implementation complexity is quite high. Maximal matching algorithms need speedup to ..."
Abstract

Cited by 2 (0 self)
 Add to MetaCart
Virtual Output Queuing is widely used by fixedlength highspeed switches to overcome headofline blocking. This is done by means of matching algorithms. Maximum matching algorithms have good performance, but their implementation complexity is quite high. Maximal matching algorithms need speedup to guarantee good performance. Iterative algorithms (such as PIM and iSLIP) use multiple iterations to converge on a maximal match. The Dual RoundRobin Matching (DRRM) scheme has performance similar to iSLIP and lower implementation complexity. The objective of matching algorithms is to reduce the matching overhead for each time slot. The Exhaustive Service Dual RoundRobin Matching (EDRRM) algorithm amortizes the cost of a match over multiple time slots. While EDRRM suffers from a throughput below 100% for small switch sizes, it is conjectured to achieve an asymptotic 100% throughput under uniform traffic. Simulations show that it achieves high throughput under nonuniform traffic. Its delay performance is not sensitive to traffic burstiness, switch size and packet length. In an EDRRM switch cells belonging to the same packet are transferred to the output continuously, which leads to good packet delay performance and simplifies the implementation of packet reassembly. In this paper we analyze the performance of an EDRRM switch by using an exhaustive service random polling system model. This was used to predict the performance of switches too large to be simulated within a reasonable run time.
M/G/∞ polling systems with random visit times
 Probability in the Engineering and Informational Sciences
, 2008
"... We consider a polling system where a group of an infinite number of servers visits sequentially a set of queues. When visited, each queue is attended for a random time. Arrivals at each queue follow a Poisson process, and service time of each individual customer is drawn from a general probability d ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
We consider a polling system where a group of an infinite number of servers visits sequentially a set of queues. When visited, each queue is attended for a random time. Arrivals at each queue follow a Poisson process, and service time of each individual customer is drawn from a general probability distribution function. Thus, each of the queues comprising the system is, in isolation, an M/G/∞type queue. A job that is not completed during a visit will have a new service time requirement sampled from the servicetime distribution of the corresponding queue. To the best of our knowledge, this paper is the first in which an M/G/∞type polling system is analysed. For this polling model, we derive the probability generating function and expected value of the queue lengths, and the LaplaceStieltjes transform and expected value of the sojourn time of a customer. Moreover, we identify the policy that maximises the throughput of the system per cycle and conclude that under the Hamiltoniantour approach, the optimal visiting order is independent of the number of customers present at the various queues at the start of the cycle. 1
Minimizing Transmission Energy in Sensor Networks via Trajectory Control
"... Abstract—Energy optimization is a significant component of Wireless Sensor Network (WSN) design. In this paper we consider transmission energy optimization in WSNs where messages are collected by a mobile receiver (collector). The collector is responsible for gathering data messages by choosing the ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
Abstract—Energy optimization is a significant component of Wireless Sensor Network (WSN) design. In this paper we consider transmission energy optimization in WSNs where messages are collected by a mobile receiver (collector). The collector is responsible for gathering data messages by choosing the optimal path that minimizes the total transmit energy at the sensors subject to a maximum travel delay constraint. We show, both analytically and through simulation, that letting the mobile collector come closer to sensors with more data to transmit leads to significant reduction in energy consumption. Using this intuition, we propose an algorithm for choosing both the transmission radii and the mobile collector’s path that achieves over 50 % improvement in energy consumption compared to schemes that use a fixed communication radius for every sensor, and a 95 % improvement as compared to the case of a stationary base station. We extend our results to the case of stochastic arrivals to the sensors and give a queueing analysis of the resulting system. We propose an AdaptiveAlgorithm that dynamically adjusts the transmission radii of the sensors based on the sensor’s current queue sizes, without requiring the knowledge of the arrival rates to the sensors. We show that it can achieve about 80 % transmission energy improvement with respect to a nonadaptive scheme that uses fixed radii based on the average arrival rates. I.
StabilityConstrained Optimization for Energy Efficiency in PollingBased Wireless Networks
, 2006
"... A wireless device’s energy can be saved by putting it into the sleeping mode (power saving mode, PSM) or decreasing its transmission power (transmission power control, TPC) which prolongs the packet transmission time. However, decreasing one’s transmission power would prevent others from transmittin ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
A wireless device’s energy can be saved by putting it into the sleeping mode (power saving mode, PSM) or decreasing its transmission power (transmission power control, TPC) which prolongs the packet transmission time. However, decreasing one’s transmission power would prevent others from transmitting their packets. Clearly, there are complex interactions when each tries to optimize its own energy efficiency. Therefore, in this paper we are considering the problem of optimizing the energy efficiency for all wireless devices in the network with the constraint that they are all stable. In particular, we consider the pollingbased MAC protocols with phase grouping and mobile grouping schedules, and we employ both the PSM and TPC to save the energy. We have formulated stabilityconstrained optimization problems for them, and have proposed an iterative algorithm to compute the optimal power allocations for the wireless devices. We have conducted a lot of experiments to validate the accuracy of the algorithm and to evaluate the gains in the energy efficiency for the two schedules. The mobile grouping schedule is found to be much more energy efficient than the PG schedule, especially when the downlink traffic is higher than the uplink traffic. We have also studied the impact of the optimized schedules on the delay performance.