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Optical-wireless convergence is becoming one of the evolutionary technologies to provide quality-of-service (QoS) guaranteed ubiquitous access to end users. In this paper, we analyze the effect of GEPON cycle-length on the QoS performance of the GEPON-LTE converged network, when different resource handling mechanisms are used. The simulation results indicate that the influence of different cycle-lengths...
This paper proposes a novel Time-threshold-based Upward Priority Scheme (TUPS) for vertical handoff in a cellular/WLAN interworking networks. In order to improve the newly blocking probability of cellular calls while guaranteeing system performance and utilization of the cellular bandwidth, the proposed scheme defines priorities for Upward Vertical Handoff (UVH) calls by using time-threshold values...
In this paper, we focus on the bandwidth allocation issue in wireless access networks, which are made up of Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) networks, i.e., Fiber-Wire (FiWi) networks. Since the bandwidth allocation scheme largely determines the performance of the entire wireless access network, in the past decades, researchers have...
Considering bandwidth limitation of networked control system (NCS), the performance of control system must be guaranteed and the bandwidth resources should be rational utilization. In order to realize the co-design of control and scheduling in networked control system, a proportion type of bandwidth allocation strategy is proposed in this paper. The remote controller which contains a QoS regulator...
In order to achieve QoS guaranteed wireless services, efficient utilization of channel resources become a fundamental issue. A number of channel allocation schemes have been proposed to fully utilize the wireless channels that include; Complete Sharing (CS), Complete partitioning (CP) and Hybrid sharing (HS) schemes. In CP the use of the un-utilized channels of one class of traffic cannot be used...
We present a new iterative mathematical model for calculating the average bandwidth assigned to traffic flows using a WRR scheduler in IP based NGN networks. The bandwidth assignment estimation is based on the average packet length, link speed and the arrival rate. We prove the model outcome with examples and simulation results using NS2 simulator.
Multicast/broadcast services (MBS) are able to provide video services for many users simultaneously. Fixed amount of bandwidth allocation for all of the MBS videos is not effective in terms of bandwidth utilization, overall forced call termination probability, and handover call dropping probability. Therefore, variable bandwidth allocation for the MBS videos can efficiently improve the system performance...
An efficient scheduling algorithm has been proposed for upstream bandwidth allocation in OFDMA PON systems to support differentiated services. Simulation result illustrates that the proposed algorithm obtains high throughput performance and channel utility.
Current high-performance capacity systems run hundreds of applications concurrently sharing the same network resources. In this scenario, system throughput and hence system utilization is significantly affected by inter-application contention. Quality-of-service (QoS) mechanisms are traditionally used in the Internet to provide different levels of performance guarantees. However, we have not found...
Quality of service (QoS) is an important issue in the deployment IEEE 802.16 networks with real-time and non-real-time traffic integration. IEEE 802.16j is an extension of IEEE 802.16 to support relay transmission. In this paper, we propose a dynamic hybrid distributed scheduling mechanism (DHSM) for IEEE 802.16j networks with non-transparent relay stations. First, we define a suitable priority for...
Femtocells are a new concept which improves the coverage and capacity of a cellular system. We consider the problem of channel allocation and power control to different users within a Femtocell. Knowing the channels available, the channel states and the rate requirements of different users the Femtocell base station (FBS), allocates the channels to different users to satisfy their requirements. Also,...
Providing that licensed or Primary Users (PUs) are oblivious to the presence of unlicensed or Secondary Users (SUs), Cognitive Radio (CR) enables the SUs to use underutilized licensed spectrum (or white spaces) opportunistically and temporarily. A centralized CR system is an architectural model for a wide range of applications for example wireless medical telemetry service and medical implant communications...
We propose a hybrid fixed/dynamic downstream scheduling scheme for 1G-EPON and 10G-EPON which enables ONU sleep mode operation for more than 90% of the time, at minor delay performance penalty and independently of network traffic.
The IEEE 802.16 standard is one of the most promising broadband wireless access systems. The standard incorporates a QoS architecture that supports both realtime and non-realtime applications. To provide QoS three data schedulers are furnished by the architecture. However, the working of the schedulers are not defined by the standard. Some researchers have attempted to fill this gap by providing different...
Heterogeneous wireless networks give rise to a multi-radio access environment which becomes crucial for load balancing to avoid network congestion and providing high quality services to maximize radio resource utilization. To this end, a joint power and bandwidth allocation with QoS support algorithm is proposed using convex optimization method in this letter. The algorithm achieves the goal of the...
In this paper, novel operating and backup channels allocation schemes for IEEE 802.22 system are introduced and their performances are investigated. Interference level and the probability of appearance for incumbent user are taken into account in order to optimally update the backup channels list. Additionally, the operating channel is allocated based on Carrier to Interference and Noise Ratio (CINR)...
Network-on-chip (NoC) is a new solution for multi-core interconnection. The static virtual channel allocation and XY routing are regularly used by the 2D mesh NoC. But the inter-core transmission congestion increases the transmission delay and decrease the throughput, which depredates the cooperation of multiple cores. This paper proposes a QoS mechanism and designs the router architecture by dynamic...
We analyze the quality of service (QoS) performance of different traffic classes in optical-wireless converged networks when different resource handling mechanisms are used. We show that in order to achieve the optimum QoS performance in the EPON-WiMAX converged network for all traffic classes, a proper combination of a dynamic bandwidth allocation algorithm, an intra ONU-BS (integrated optical network...
The integration of WiMAX networks with EPON networks combine the large bandwidth availability in optical access networks with the mobility provided by wireless technologies. In this integration, a WiMAX bandwidth scheduler that takes into account the variability of the channel capacity provided by the EPON scheduler is quite important, since the granted bandwidth must be sufficient to support the...
This paper proposes an algorithm of bandwidth allocation based on wireless access network 802.16d standard. First distributes the bandwidth in different services then redistributes the bandwidth in different connection of one service. By the test of simulation platform of the IEEE 802.16 using OPNET, the algorithm guarantees time-delay of the real-time polling service and it also satisfies the fairness...
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