Frame Scheduling Research Articles

A Co-Design for CAN-Based Networked Control Systems

The goal of this paper is to consider a co-design approach between the controller of a process control application and the frame scheduling for CAN-Based Networked Control Systems in order to simultaneously improve the Quality of Control (QoC) of the process control and the Quality of Service (QoS) of the CAN-based network. First, we present a way to calculate the closed-loop communication time delay and we compensate this time delay using the pole-placement design method. Second, we propose a hybrid priority scheme for the message scheduling which allows to improve the QoS. Finally, we present a co-design of the communication time delay compensation and the message scheduling, which gives a more efficient Networked Control System

High Performance and Hardware Efficient Multiview Video Coding Frame Scheduling Algorithms and Architectures

Multiview video coding (MVC) provides more realistic 3-D scenes adding depth information derived from multiple cameras than single-or stereo-view video coding. In MVC, video frames obtained from each view are simply scheduled to corresponding encoding channels. However, under such a conventional scheduling technique the encoding times of each channel may not be identical, degrading encoding performance. To address this problem, this paper proposes two MVC frame scheduling schemes and their architectures: a hardware resource aware scheduling and a frame waiting time aware scheduling (WTaS). Here, WTaS considers the waiting time of each frame stored in on-chip SRAM during frame scheduling, thereby reducing SRAM size significantly. Experimental results show that the proposed frame scheduling schemes provide 29.4% faster processing time, compared to the conventional counterpart. In addition, we can improve the core area, on-chip SRAM area, and the power dissipation by 26.7%, 23.2%, and 26.6%, respectively.

Frame Assembly and Scheduling on Edge Routers in Fixed-Size Frame-Switching Networks

Frame assembly is seen as an important technology in future core networks since it can mitigate the ever-increasing packet header processing load on network nodes. Since frame assembly changes the pattern of traffic entering the network, it has a significant impact on such aspects of network performance as packet drop probability and end-to-end delay. This paper focus on the packet drop and delay performance on assembly nodes, sometimes called edge routers. We reveal that frame assembly on edge routers is in fact a tradeoff between packet loss performance and fairness, especially when the input client traffic is non-uniformly distributed among multiple destinations. We evaluate existing frame assembly and scheduling algorithms and try to cope with the assembly and scheduling process holistically by proposing a new algorithm, named highest efficiency fair queuing. Simulation results show that the proposed algorithm provides better performance in terms of delay and jitter, while also minimizing the average packet loss rate.

The Scheduling Frame Research Facing Rapid Response Manufacturing

The current environment is experiencing a transformation from multi varieties and little batch to multi varieties and batch, this situation has result that companies’ management do not suite it. According to this the scheduling frame research facing rapid response manufacturing has been proposed. At first through this analyzing the problem in current situation, the whole scheduling frame is researched. Secondly, many models that can be used in this frame have been discussed such as manufacturing information, disturbance events, automatic scheduling and dynamic scheduling models. Finally the whole scheduling platforms which can be used in practical situation has been proposed and make a technical function base for current manufacturers.

Scheduling performance enhancement by network coding in wireless mesh networks

When a wireless mesh network accommodates interactive applications with quality of service requirements, schedule-based protocols are more suitable than contention-based protocols. In this paper, the problem of determining an appropriate schedule assignment for multiple group transmissions within a spatial time division multiple access link scheduling network is referred to as an integrated multiple-group communication and link scheduling problem. A polynomial-time scheduling algorithm, designated as a source-parallel-aware assignment (SPAA), is proposed to increase the spatial utilisation within each time slot in order to enhance the network throughput. Furthermore, an advanced version of SPAA, designated as joint source-parallel-aware assignment with network coding (JSANC), is proposed to reduce the effects of bottleneck paths on the schedule frame length by flexibly applying conventional or opportunistic network coding approaches. Simulation results show that the proposed algorithms achieve a better network throughput than existing flow-based or particular order-based scheduling schemes.

Guest Editorial Special Section on Real-Time and (Networked) Embedded Systems III

The four papers in this special section present some of the latest developments in the area of real-time and networked embedded systems, from software worst-case execution-time analysis, to predictable software synchronization, to frame scheduling on wireless sensor networks, and finally to the design and implementation of a time-critical control system over real-time Ethernet.

Efficient group multicast node scheduling schemes in multi-hop wireless networks

STDMA networks provide an effective solution for enabling wireless devices to access network resources with fairness and efficiency. When multiple-group communications are implemented in such networks, the scheduling algorithm should generate appropriate schedule assignments for all the transmissions where the objective aims to reduce the schedule length. In this paper, the problem of producing an efficient schedule sequence for multiple-group communications over a STDMA node scheduling network is referred to as an integrated multiple-group communication and traffic-oriented node scheduling (IMCTNS) problem. It is shown that the IMCTNS problem can be formulated as an integer linear programming (ILP) problem. A polynomial-time centralized heuristic scheduling algorithm, designated as Broadcasting Level-by-Level Scheduling (B-LBLS), is proposed for determining the schedule sequence subject to transmission constraints. To enhance the spatial utilization efficiency within each time slot, an advanced version of B-LBLS, designated as Collision-Allowed Level-by-Level Scheduling (CA-LBLS), is proposed based on a modified graph-based interference model. It is shown that compared to existing TDMA- and STDMA-based algorithms, the proposed algorithms provide an effective reduction in the schedule frame length and a significant increase in the spatial utilization within each time slot.

Design and Analysis of AFDX Network Based High-Speed Avionics System of Civil Aircraft

Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for integrated avionics systems of civil aircraft. It becomes the current communication technology in the context of avionics and provides a backbone network for the civil avionics system. This paper focuses on features of AFDX network protocol. Architecture of AFDX switch based on shared memory is proposed to meet the requirements of avionics real-time system. In addition, frame filtering, traffic policing and frame schedule function are used to eliminate uncertainties in huge traffic flows. End System (ES) host-target architecture is also researched in this paper. Virtual link scheduler, redundancy management, and protocol stack in ES are designed to ensure determinism and reliability of data communication. AFDX switch and ES have been successfully developed, and configuration tool, ARINC 615A loader and simulation tool related to AFDX network are also provided as package solution to support avionics system construction. Finally, AFDX switch and ESes have passed ARINC 664 protocol conformance test and certification, the test results show that our AFDX products meet the requirements of real-time communication, determinism and reliability defined in ARINC 664

Transmission scheduling algorithm for MIMO link ad hoc networks

Most reported works on transmission scheduling algorithm for multiple input multiple output (MIMO) link ad hoc networks do not fully exploit the spatial multiplexing potential inherent to multiple antennas system. In this paper, a novel transmission scheduling algorithm is proposed to further enhance the performance of MIMO link ad hoc networks. By utilizing the MIMO multi-stream reception capabilities and ordering the nodes’ allocation sequence, the proposed algorithm can dramatically shorten the scheduling frame length and more evenly distribute the data streams allocated to the network nodes. Meanwhile, allowing the nodes to transmit multiple streams in a slot, the algorithm can fully exploit the MIMO spatial multiplexing potential. Additionally, we give the theoretical analysis to quantify the throughput and delay performance with respect to this scheme. Numerical results demonstrate that the proposed algorithm can efficiently enhance the network throughput and reduce the average and maximum delay.

Minimizing multiplayer interactive delay in multihop wireless networks

SUMMARYMinimizing the schedule frame length in spatial time division multiple access networks is essential in enhancing the performance of multiplayer interactive applications in multiple‐group multicasting environments. In this paper, the joint link scheduling and multiple‐group communication problem in such networks is referred to as a real‐time multiple‐group communication tree scheduling (RMGCTS) problem in which the objective is to minimize the total schedule frame length. It is shown that the RMGCTS problem can be represented as an integer linear programming problem. Two particular RMGCTS problems are considered, namely, back‐to‐back RMGCTS for applications with a receiving‐jitter constraint, and general RMGCTS for applications with a delay constraint. Two heuristic algorithms, designated as back‐to‐back scheduling and level‐by‐level scheduling, are proposed to provide efficient solutions of the back‐to‐back and general RMGCTS problems by maximizing the spatial reuse capability within each time slot, thereby minimizing the schedule frame length. The simulation results show that the proposed schemes yield an effective reduction in the length of the multicast schedule frame compared to that obtained from existing tree‐based or pure‐color scheduling algorithms. Copyright © 2011 John Wiley & Sons, Ltd.

Schedule Optimization of Time-Triggered Systems Communicating Over the FlexRay Static Segment

FlexRay is a new high-bandwidth communication protocol for the automotive domain, providing support for the transmission of time-critical periodic frames in a static segment and priority-based scheduling of event-triggered frames in a dynamic segment. The design of a system scheduling with communication over the FlexRay static segment is not an easy task because of protocol constraints and the demand for extensibility and flexibility. We study the problem of the ECU and FlexRay bus scheduling synthesis from the perspective of the application designer, interested in optimizing the scheduling subject to timing constraints with respect to latency- or extensibility-related metric functions. We provide solutions for a task and signal scheduling problem, including different task scheduling policies based on existing industry standards. The solutions are based on the Mixed-Integer Linear Programming optimization framework. We show the results of the application of the method to case studies consisting of an X-by-wire system on actual prototype vehicles.

Prevalence of hypertension in Algeria

PRAMIAL study was led to estimate prevalence of peripheral arterial disease in a general population which consults in a not scheduled frame. After the inclusion of 1000 subjects, the objectives of the preliminary results aim are estimating prevalence of hypertension adjusted on the Algerian population and the control of this burden. The mean age of this cohort is of 57.2 years. Prevalence of hypertension is 29%. The pecentage of hypertensive controlled patients is 46%. Prevalence of PAD in this population is 3.1%. The most prescribed antihypertensive drugs are in a lessening order: ACE inhibitors, calcium channel blockers, angiotensin II receptor antagonist, diuretics and beta blockers. PRAMIAL study was led to estimate prevalence of peripheral arterial disease in a general population which consults in a not scheduled frame. After the inclusion of 1000 subjects, the objectives of the preliminary results aim are estimating prevalence of hypertension adjusted on the Algerian population and the control of this burden. The mean age of this cohort is of 57.2 years. Prevalence of hypertension is 29%. The pecentage of hypertensive controlled patients is 46%. Prevalence of PAD in this population is 3.1%. The most prescribed antihypertensive drugs are in a lessening order: ACE inhibitors, calcium channel blockers, angiotensin II receptor antagonist, diuretics and beta blockers.

Efficient Frame Schedule Scheme for Real-time Video Transmission Across the Internet Using TCP

The great end-to-end delays are the major factor to influence the visual quality of real-time video across the Internet using TCP as transport layer protocol. In this paper, we present a video frame schedule scheme for rate adaptive real-time video transmission over TCP. The scheme schedules video frames between the application layer sender-buffer, the TCP sender-buffer and TCP receiver-buffer and can regulate automaticlly the video frame rate and play out buffer delays according to the network congestion level. The sheme requires only an extra buffer of application layer and can significantly cut down the end-to-end delays of real-time video without any modification to the network infrastructure or TCP protocol stack. The performance of the proposed solution is evaluated through extensive simulations using the NS-2 simulator.

Joint power, subcarrier and subframe allocation in Multihop relay networks

AbstractIn this paper we study the problem of subframe, subchannel and power allocation in OFDMA‐based multihop relay networks. The system consists of a base station (BS), a number of relay stations (RS) and mobile stations (MS). We consider frame by frame scheduling, where the frame is divided into two subframes such as BS‐RS and RS‐MS subframes. We study two different problems, satisfying link rate requirements with minimum‐weighted total power and maximizing proportional fairness. For the first problem, we find the optimal solution and also propose a less complex subframe and bandwidth allocation scheme with good performance. For the second problem, we propose an algorithm that outperforms an existing scheme with less feedback. Copyright © 2009 John Wiley & Sons, Ltd.

Scheduling in overlaid star all-photonic networks with large propagation delays

This paper describes a framework for fixed- length frame scheduling in all-photonic networks with large propagation delays. We introduce the Fair Matching Algorithm a novel scheduling approach that results in weighted max-min fair allocation of extra slots, achieves zero rejection for admissible demands, and minimizes the maximum percentage rejection of any connection. We also propose the Minimum Rejection Algorithm, which minimizes total rejection but treats non-critical connections in a fair manner. Finally, we introduce a feedback control system based on Smith’s principle that reduces the effect of prediction errors and increases the speed of the response to the sudden changes in traffic arrival rates. Simulations performed using OPNET Modeler explore the performance of the scheduling and control algorithms we propose.

Cross-Layer Proportional Fair Scheduling with Packet Length Constraint in Multiuser OFDM Networks

In this paper, we investigate the proportional fair scheduling (PFS) problem for multiuser OFDM systems, considering the impact of packet length. Packet length influences scheduling schemes in a way that each scheduled packet should be ensured to be completely transmitted within the scheduled frames. We formulate the PFS problem as an optimization problem. Based on the observations on the structure of optimal solutions, we propose a heuristic scheduling algorithm that consists of two stages. First, subcarriers are allocated among users without considering the packet length constraint. Then on the second stage, subcarrier readjustment is done in a way that surplus subcarriers from length-satisfied users are released and allocated among length-unsatisfied users. The objective is to provide proportional fairness among users while guaranteeing complete transmission of each scheduled packet. Simulation results show that the proposed scheme has quite close performance to the optimal scheme in terms of Multi-carrier Proportional Fairness Measure (MCPFM), throughput and average packet delay.

Topology-Independent Link Activation Scheduling Schemes for Mobile CDMA Ad Hoc Networks

In this paper, we study medium access control (MAC) protocols with quality-of-service (QoS) support, that is, topology-independent link activation transmission scheduling, for mobile code-division multiple-access (CDMA) ad hoc networks. QoS provisioning for each communication link is guaranteed without the need to adopt transmission schedules in mobile environments. An interference model, which captures the difference between transmission and interference ranges, is considered. Under this interference model, an approach to guaranteeing conflict-free transmission slots in each frame (QoS provisioning) for each communication link is proposed. Compared with the previously known method, superior performance is obtained. We then present a topology-independent link activation scheduling framework based on the theory of group-divisible (GD) designs. By the mathematical properties of GD designs, the proposed framework guarantees conflict-free transmission slots in each frame for each communication link, without the overhead due to the recomputation of transmission schedules when the network topology changes. With the proposed framework, we study and evaluate one series of GD design constructions. Based on the results derived, topology-independent link activation scheduling algorithms are then presented. The proposed schemes are designed for different objectives: maximizing the minimum system throughput and/or minimizing the schedule frame length. Numerical results show that the proposed algorithms outperform previously known schemes. The average performance of the proposed schemes is also derived.

On the Implementation of one Process Control Application Type through a Network. Considering Three LANS: CAN, WiFi, ZigBee

This paper wants to present the first reasoning in order to implement on a network a process control application type which is, in a first time, specified with a continuous model (transfer function in the Laplace domain). The network is a local area network and we only consider the MAC layer (frame scheduling) and the physical layer (serial frame transmission). By first reasoning, we mean that, we study the case of a network which is dedicated to the process control application type, and we want to link the stability and the reactivity that the application can get from the service provided by the network (link between the parameters of the open loop transfer function and the network characteristics (frame transfer, frame format, bit rate)). Three networks are considered: CAN, WiFi, ZigBee. This work is a basic work which wants to emphasize the necessary interplay between Automatic Control theory and Networks mechanisms.

Optimized H.264/AVC-Based Bit Stream Switching for Mobile Video Streaming

We show the suitability of H.264/MPEG-4 AVC extended profile for wireless video streaming applications. In particular, we exploit the advanced bit stream switching capabilities using SP/SI pictures defined in the H.264/MPEG-4 AVC standard. For both types of switching pictures, optimized encoders are developed. We introduce a framework for dynamic switching and frame scheduling. For this purpose we define an appropriate abstract representation for media encoded for video streaming, as well as for the characteristics of wireless variable bit rate channels. The achievable performance gains over H.264/MPEG-4 AVC with constant bit rate (CBR) encoding are shown for wireless video streaming over enhanced GPRS (EGPRS).

QoS Mechanisms for the MAC Protocol of IEEE 802.11 WLANs

There are two essential ingredients in order for any telecommunications system to be able to provide Quality-of-Service (QoS) guarantees: connection admission control (CAC) and service differentiation. In wireless local area networks (WLANs), it is essential to carry out these functions at the MAC level. The original version of IEEE 802.11 medium access control (MAC) protocol for WLANs does not include either function. The IEEE 802.11e draft standard includes new features to facilitate and promote the provision of QoS guarantees, but no specific mechanisms are defined in the protocol to avoid over saturating the medium (via CAC) or to decide how to assign the available resources (via service differentiation through scheduling). This paper introduces specific mechanisms for both admission control and service differentiation into the IEEE 802.11 MAC protocol. The main contributions of this work are a novel CAC algorithm for leaky-bucket constrained traffic streams, an original frame scheduling mechanism referred to as DM-SCFQ, and a simulation study of the performance of a WLAN including these features.