Masoomeh Torabzadeh - Academia.edu (original) (raw)

Papers by Masoomeh Torabzadeh

The emergence features of 5G networks will be concentrated on an enhancement of quality of experi... more The emergence features of 5G networks will be concentrated on an enhancement of quality of experience in conformity with SLA service contracts. Most previous massive MIMO schedulers do not take into account the traffic characteristics of 5G (different packet lengths and the arrival process parameters) and QoS (Quality of Service) requirements; consequently, they fall short of simultaneously providing fairness and a low average packet transmission delay for users. The paper addresses an important problem related to scheduling of 5G traffic in a fair and energy efficient way using a state-of-the art formulation of energy efficient scheduling. It is based on an OFDM multicarrier scheme in which all users use all subcarriers. The proposed scheme is backed by an extensive set of simulations.

電子情報通信学会ソサイエティ大会講演論文集, Sep 7, 2006

International Conference on Networking, International Conference on Systems and International Conference on Mobile Communications and Learning Technologies (ICNICONSMCL'06), 2006

The phenomenon of traffic burstiness is a big challenge in the switching equipments of the core o... more The phenomenon of traffic burstiness is a big challenge in the switching equipments of the core of computer network, because it leads to more delay and jitter to be tolerated by users. Therefore, we should use all of the available facilities to improve the traffic behavior. In this paper, we present an idea based on delay management and QoS considerations to decrease the variances in short-time scales. Using our approach the impact of short-term burstiness will be decreased. Also, this idea can be implemented in MPLS ingress nodes or by delay management of paths in MPLS traffic engineering when we have congestion in the network.

Lecture Notes in Computer Science, 2004

Abstract. One of the services for which SIP was first introduced is the confer-encing in large sc... more Abstract. One of the services for which SIP was first introduced is the confer-encing in large scale. Large-scale conferencing on Internet imposes a lot of load on conference components. In this paper, a technique has been presented for improvement of a secure ...

Proceedings of the 6th International Wireless Communications and Mobile Computing Conference on ZZZ - IWCMC '10, 2010

We investigate the packet-level scheduling for the downlink of multiple-input multiple-output (MI... more We investigate the packet-level scheduling for the downlink of multiple-input multiple-output (MIMO) multiuser systems using beamforming. We consider the traffic arrival process and different packet lengths. We tackle low-complex practical implementation that provides low average packet transmission delay and bit error rates (BER) to users. We propose a work-conserving scheduling scheme that considers different users guarantees (heterogeneous users). We implement and compare different MIMO schedulers at the packet level. Simulations show the low average packet transmission delay and bit error rate of our proposed scheduler.

Proceedings of 15th International Conference on Computer Communications and Networks, 2006

The antennas array in multiple-input multiple-output (MIMO)-based systems can be used to increase... more The antennas array in multiple-input multiple-output (MIMO)-based systems can be used to increase the data rate. Besides, many fair scheduling algorithms have been proposed for wireless networks with single antenna, single rate or multiple rates. However, a multi-output fair packet ...

2007 International Conference on Wireless Communications, Networking and Mobile Computing, 2007

ABSTRACT The problem of allocating network resources to the users of a cellular network with mult... more ABSTRACT The problem of allocating network resources to the users of a cellular network with multiple antennas in a fair way is investigated. We propose a packet scheduler called MIMO packet-by-packet generalized processor sharing (MPGPS). The scheduler can provide fair access to the channels for users and is work conserving. It also compensates lagging users and decreases the average delay of users. Comparisons with a couple of scheduling algorithms considering traffic characteristics and the mobility of users demonstrate the superior performance of our scheduler.

2007 3rd IEEE/IFIP International Conference in Central Asia on Internet, 2007

Multiple-input multiple-output (MIMO) wireless antenna systems are known as the effective means t... more Multiple-input multiple-output (MIMO) wireless antenna systems are known as the effective means to achieve high capacity over wireless links. In this paper, we propose an adaptive packet-by-packet scheduling scheme, which considers channel state information, user's average throughput, and queueing state information when making scheduling decision. Our proposed scheduler, adaptive proportional fairness with queue length consideration (APF-Q), is work conserving and can provide low delay of users in a fair way. Numerical results taking into consideration traffic characteristics and the mobility of users demonstrate the superior performance of the proposed APF-Q scheduler.

2007 15th IEEE International Conference on Networks, 2007

Abstract High performance, low complexity schedulers are challenging to develop for the downlink... more Abstract High performance, low complexity schedulers are challenging to develop for the downlink of multiple-input multiple-output (MIMO) cellular systems. Selection among available channels between users and the base station in a centralized way makes the problem complex. An ...

2006 2nd IEEE/IFIP International Conference in Central Asia on Internet, 2006

2006 10th IEEE Singapore International Conference on Communication Systems, 2006

Multiple-input multiple-output (MIMO) is today's technology of wireless systems that gains m... more Multiple-input multiple-output (MIMO) is today's technology of wireless systems that gains multiple antennas to provide high data rates. The nature of independent time-varying channels across different users in a multi-user wireless system provides multi-user diversity. In addition, ...

2007 Fourth International Conference on Broadband Communications, Networks and Systems (BROADNETS '07), 2007

In this paper, we address the problem of cross layer scheduling for the downlinks of multiple-inp... more In this paper, we address the problem of cross layer scheduling for the downlinks of multiple-input multiple-output (MIMO) cellular systems. Previously proposed MIMO schedulers have problems such as ignoring traffic arrival process or complexity. We focus on designing an adaptive fair scheduling algorithm to traffic load changes. We propose a load adaptive multi-output fair queueing (LA-MO-FQ) scheduler, which is based on a fair queueing algorithm with mechanisms for rate selection, compensation of lagging users, and virtual time system. Since some of the scheduler’s system parameters are sensitive to the traffic load, it dynamically adjusts them in a way with low complexity so the system performs better. Furthermore, we also propose in this paper some formulae for the time and service fairness comparisons of MIMO schedulers. Intensive simulation studies considering the mobility of users and the traffic characteristics demonstrate the good performance of LA-MO-FQ. Finally, we compare both the performance and fairness of our scheduler with some famous existing schedulers.

2008 IEEE Wireless Communications and Networking Conference, 2008

The key issue we address in this paper concerns how the available bandwidth within the downlink o... more The key issue we address in this paper concerns how the available bandwidth within the downlink of a multiple-input multiple-output (MIMO) cellular network should be shared between competing users to achieve both fairness and high system throughput. We propose a high performance packet scheduling framework, called MIMO packet-based proportional fairness (MP-PF). The scheduler is work conserving and based on a novel proportional fairness concept that takes the packet length, users&#x27; backlogs, and users&#x27; guarantees into consideration. Furthermore, we gain an efficient packet-based framework in the MAC layer. Intensive simulation studies that took into consideration the traffic characteristics and the mobility of the users were used to demonstrate the superior performance of our scheduling framework for both the average delay of users and the time/service fairness. We also propose two useful equations for the time/service comparison of MIMO schedulers.

2008 IEEE International Conference on Wireless and Mobile Computing, Networking and Communications, 2008

Packet scheduling at the data link layer may impact significantly the overall performance of a wi... more Packet scheduling at the data link layer may impact significantly the overall performance of a wireless system using multiple antennas. In this paper, we propose a novel packet scheduling scheme based on proportional fairness that considers the traffic arrival process with different packet lengths for the downlink of multiple-input multiple-output (MIMO) multiuser systems. We also provide analysis for the fairness of the new scheme in terms of time and service allocation. The scheduler, referred to as clock-time proportional fairness (C-T PF), performs at the packet level and can provide low average packet transmission delay as well as time and service fairness to users. It is work conserving and it can also take into consideration different users guarantees (heterogeneous users). We investigate an ideal service fair scheduler called C-T max-min for MIMO systems as well. We compare the performance of C-T PF with other MIMO schedulers. For the time and service fairness comparison of MIMO schedulers, we also propose time and service indexes. Simulations that consider the traffic characteristics and the mobility of users show the low average packet transmission delay and demonstrate the time and service fairness capabilities of C-T PF. I.

2009 IEEE Radio and Wireless Symposium, 2009

In this paper, the well known proportional fairness scheduling is investigated when we joint tran... more In this paper, the well known proportional fairness scheduling is investigated when we joint transmit beamforming and packet level scheduling taking into consideration the traffic arrival process with different packet lengths for the downlink of multiple-input multiple-output (MIMO) multiuser systems. The new scheduler called the proportional fairness zero-forcing beamforming (PF-ZB) can perform at the packet level and provide low average packet transmission delay as well as fairness to users. The scheduler is work conserving. We compare the performance of our scheduler with another well known MIMO scheduler when it is performing in the packet level with transmit beamforming. Simulations that consider the traffic characteristics show the low average packet transmission delay and demonstrate the fairness capabilities of PF-ZB.

2008 33rd IEEE Conference on Local Computer Networks (LCN), 2008

In this paper, we propose a new switching scheme to improve the short-term delay and the packet j... more In this paper, we propose a new switching scheme to improve the short-term delay and the packet jitter for real-time traffic. Even though, the proposed scheme is general and can be used in different points of the network, we propose to use it in MPLS ingress nodes. In our plan, we manage the delay to improve the QoS provisioning in a flexible manner, since traditional mechanisms such as leaky bucket can not have such kind of flexibility. Also, after using the scheme in MPLS ingress node the impact of short-time scale burstiness of the traffic will be decreased. The performance analysis shows that high quality of service provisioning for the real-time traffic will be achieved. I.

Journal of Communications, 2011

We propose a novel classifier technique, named short-time burst degradation classifier (SBDC), wi... more We propose a novel classifier technique, named short-time burst degradation classifier (SBDC), with the ultimate goal of improving the short-term delay and the packet jitter for real-time traffic. The main idea of the proposed classifier is to provide the ability to manage the queuing delay in order to decrease the impact of short-time scale burstiness of the traffic in a flexible manner, since traditional mechanisms such as leaky bucket cannot have such kind of flexibility to smooth the traffic. Even though the proposed scheme is general and can be used in different points of the network, we propose to implement it in MPLS ingress nodes. To evaluate the performance of the proposed classifier, we introduce a new efficient scheduler, called short-term quality-of-service class based queuing (SQ-CBQ), to be combined with our classifier. The scheduler is based on a new scheduling algorithm named polling deficit round robin (PDRR). Also, after using the combination of the classifier and the scheduler in MPLS ingress nodes, the sort-term QoS provisioning is improved. The performance analysis shows that high quality of service provisioning for the real-time traffic can be achieved by implementing our proposed scheduler and classifier, compared to the traditionally implemented switching schemes. 1

IEICE Transactions on Communications, 2007

ABSTRACT Multiple-antenna wireless systems, also known as multiple-input multiple-output (MIMO) c... more ABSTRACT Multiple-antenna wireless systems, also known as multiple-input multiple-output (MIMO) cellular networks, can improve the capacity and reliability of communications. To realize these advantages, a packet scheduler should effectively allocate radio resources to users in a fair way. The previously proposed MIMO schedulers have problems such as ignoring traffic arrival process or complexity. We propose a load adaptive multi-output fair queueing (LA-MO-FQ) scheduler, which is based on a fair queueing algorithm with mechanisms for rate selection, compensation of lagging users, and virtual time system. Since some of the scheduler's system parameters are sensitive to the traffic load, it dynamically adjusts them in a way with low complexity so the system performs better. Intensive simulation studies considering the mobility of users and the traffic arrival demonstrate the good performance of LA-MO-FQ. Furthermore, we also propose in this paper some formulae for the time and service fairness comparisons of MIMO schedulers and we use them for comparison with some famous existing schedulers.

IEEE Transactions on Vehicular Technology, 2010

AbstractThis paper investigates the network resource allo-cation in multiuser downlink wireless ... more AbstractThis paper investigates the network resource allo-cation in multiuser downlink wireless systems where the base station and the mobile stations are equipped with multiple an-tennas to provide fair and efficient transmission services to the mobile users. We focus on packet ...