Multicast Scheduling Algorithm Research Articles

Device-to-Device Communications Enabled Multicast Scheduling with the Multi-level Codebook in mmWave Small Cells

To keep up with the rapid growth of mobile data, there are increasing interests to deploy small cells in millimeter wave (mmWave) bands to underlay the conventional homogeneous macrocell network as well as in exploiting device-to-device (D2D) communications to improve the efficiency of the multicast service that supports content-based mobile applications. To compensate for high propagation loss in the mmWave band, high-gain directional antennas have to be employed, while it is critical to optimize multicast service in order to improve the network performance. In this paper, we develop an efficient multicast scheduling scheme for small cells in the mmWave band, called MD2D, where both D2D communications in close proximity and multi-level antenna codebook are utilized. Specifically, a user partition and multicast path planning algorithm is proposed to partition the users in the multicast group into subsets and to determine the transmission node for each subset, so as to achieve optimal utilization of D2D communications and multi-level antenna codebook. Then a multicast scheduling algorithm schedules the transmission for each subset. Furthermore, in order to optimize the network performance, the optimal choice of user partition thresholds is analyzed. Extensive simulations demonstrate that the MD2D achieves the best performance, in terms of network throughput and energy efficiency, compared with other existing state-of-the-art schemes. MD2D improves the network throughput compared with the second-best scheme by about 27%.

Throughput Analysis of Multicast Scheduling Algorithms by Varying NxN IQ Switch

Throughput Analysis of Multicast Scheduling Algorithms by Varying NxN IQ Switch

Multicast Scheduling of Wavelength-Tunable, Multiqueue Optical Data Center Switches

The all-optical switching of multicast flows using star couplers and tunable transceivers is a promising solution for emerging cloud data center applications. However, the limited tuning range of optical components on one hand and the buffer management challenges for multicast traffic delivery on the other pose a significant impact on the performance of optical multicast scheduling algorithms. Using only one queue per input port results in head-of-line (HOL) blocking and limits the throughput, especially for bursty traffic patterns. As the number of possible multicast destinations grows exponentially with the switch size, allocating one queue per destination is not a feasible solution. To resolve HOL blocking, in this paper we consider only a handful of queues per switch input port and devise scalable scheduling algorithms that take into account transceiver tunability constraints. According to our Monte Carlo analysis of a switch with 64 ports and operating under bursty traffic, it is possible to improve the maximum achievable throughput by 44% when the number of queues per port is increased from one to eight. We show that the performance gains due to an increase in the queue count depend on the availability of the spectral resources. With the scarcity of wavelengths, an increase in the number of queues leads to diminishing returns.

Application and Analysis of Multicast Blocking Modelling in Fat-Tree Data Center Networks

Multicast can improve network performance by eliminating unnecessary duplicated flows in the data center networks (DCNs). Thus it can significantly save network bandwidth. However, the network multicast blocking may cause the retransmission of a large number of data packets and seriously influence the traffic efficiency in data center networks, especially in the fat-tree DCNs with multirooted tree structure. In this paper, we build a multicast blocking model and apply it to solve the problem of network blocking in the fat-tree DCNs. Furthermore, we propose a novel multicast scheduling strategy. In the scheduling strategy, we select the uplink connecting to available core switch whose remaining bandwidth is close to and greater than the three times of bandwidth multicast requests so as to reduce the operation time of the proposed algorithm. Then the blocking probability of downlink in the next time-slot is calculated in multicast subnetwork by using Markov chains theory. With the obtained probability, we select the optimal downlink based on the available core switch. In addition, theoretical analysis shows that the multicast scheduling algorithm has close to zero network blocking probability as well as lower time complexity. Simulation results verify the effectiveness of our proposed multicast scheduling algorithm.

Battery Status Sensing Software-Defined Multicast for V2G Regulation in Smart Grid

During the bidirectional exchange of electricity between electric vehicles (EVs) and smart grid, plenty of sensors have been deployed to sense the EVs’ battery status and monitor the electricity regulation requirements. When electricity consumption at power grid demand-side sharply increases/decreases, charging points (CPs) access these sensors by multicast technology to aggregate the EVs’ battery status, publish electricity regulation requests and assign the state of charge (SOC) transition instructs in vehicle-to-grid (V2G). However, intermittent connections arising from distributed and mobile energy storage bring many challenging problems on multicast scheduling. First, in smart grid, peak shaving and load shifting require V2G to sense and regulate the EVs’ SOC according to their battery status precisely, while the traditional multicast only considers their mutable network locations (e.g., WLAN, IP, and MAC). Second, as the number of EVs that participate into V2G increases, V2G needs to schedule the massive multicast traffic with priority to satisfy the dynamic and real-time regulation requirements. To address these problems, in this paper, we first aim to demonstrate that the appreciable battery status is more adaptive than network location to act as a multicast primitive in V2G. We propose a battery status sensing software-defined multicast (BSS-SDM) scheme to reduce the latency of V2G regulation services. In the BSS-SDM scheme, the battery status of each EV is identified during SOC transitions and maintained by a centralized controller. Besides, we propose a battery-status-based multicast scheduling algorithm to implement the V2G regulation optimization. Simulation results verify the effectiveness of proposed schemes.

Frame based multicast scheduling for buffered Clos-network switches

Buffered Clos-network switches have advantages of modularity and simplicity; however, they are limited to serious out-of-sequence problems, especially when serving multicast traffic. In this study, a frame-based multicast scheduling algorithm for memory-memory-memory Clos networks (FMClos) is proposed. Multicast cells are replicated at the first and last stages based on address-copy technology, which eliminates head-of-line (HoL) blocking and improves throughput performance. The frame-based scheduling scheme performed at the input module, as well as the buffered crossbar switch element adopted by the central module, contributes to reducing the out-of-sequence (OOS) cells. Simulation results show that FMClos scheme can achieve nearly 100% throughput. In comparison with existing algorithms, the proposed method decreases the proportion of OOS cells and considerably reduces resequencing delay under heavy traffic load.

Blocking cost‐driven multicast scheduling in fat‐tree data center networks

SummaryMulticast traffic scheduling in data center networks can not only improve network efficiency but also save network resources. However, the existing multicast scheduling algorithms cannot appropriately schedule flows to achieve traffic load balance so that the network may occur heavy blocking. This prevents the full utilization of high degree of link parallelism and causes unpredictable reduction of network performance. To address the problem, in this paper, we propose a blocking cost‐driven multicast scheduling algorithm by using optimization theory in fat‐tree data center networks. In particular, a model of multicast traffic subnetwork is established on the basis of the blocking probability of available paths at next time slot, which can reflect the blocking characteristics of multicast network and predict network state at next time slot. With the multicast blocking model, we derive the minimum blocking probability of multicast subnetworks, denoted as blocking cost. In addition, the algorithm can select the multicast subnetwork with minimum blocking cost to transfer multicast flows. Time complexity analysis and simulation results demonstrate the effectiveness and efficiency of our proposed multicast scheduling algorithm for different network traffic intensities.

밀집 무선랜 시스템에서의 멀티캐스트 전송 스케줄링 기법

최근 무선 디바이스의 증가와 무선랜 사용자가 급증하면서 다수의 AP와 여러 노드가 존재하는 밀집 네트워크 환경이 발생한다. 다수의 AP가 존재하는 환경에서 중첩영역에 대한 고려 없이 멀티캐스트 데이터를 전송할 경우 노드의 위치에 따라서 메시지 중복 수신과 빈번한 데이터 충돌이 발생할 수 있다. 본 논문에서는 밀집 무선랜 시스템에 적합한 새로운 멀티캐스트 전송 스케줄링 기법을 제안한다. 제안하는 멀티캐스트 전송 기법은 단일 전송환경과 다중 전송 환경을 모두 고려하며 각 AP의 최적의 전송 순서를 스케줄링 함으로써 불필요한 중복전송을 제거하고 데이터 충돌을 방지한다. 시뮬레이션 결과를 통하여 제안하는 기법이 비교 기법들에 비해서 전송시간이 감소하고, 밀집 네트워크 환경에서 효율적인 멀티캐스트 전송을 하는 것을 확인할 수 있다. Nowadays, many WLAN access points (APs) are deployed in hotspot areas such as shopping malls and stations. As the number of WLAN APs deployed increases, how to manage densely deployed APs in an efficient manner becomes one of the most important issues in WLANs. In this environment, uncoordinated multicast services can lead to frequent collisions due to simultaneous transmissions among APs. In this paper, we propose a multicast scheduling algorithm that can exploit simultaneous transmissions in multiple sectors and avoid redundant transmissions in dense networks. Simulation results demonstrate that the proposed scheme can reduce the multicast transmission latency compared to comparison scheduling schemes.

Efficient round‐robin multicast scheduling for input‐queued switches

The input-queued (IQ) switch architecture is favoured for designing multicast high-speed switches because of its scalability and low implementation complexity. However, using the first-in-first-out (FIFO) queueing discipline at each input of the switch may cause the head-of-line (HOL) blocking problem. Using a separate queue for each output port at an input to reduce the HOL blocking, that is, the virtual output queuing discipline, increases the implementation complexity, which limits the scalability. Given the increasing link speed and network capacity, a low-complexity yet efficient multicast scheduling algorithm is required for next generation high-speed networks. This study proposes the novel efficient round-robin multicast scheduling algorithm for IQ architectures and demonstrates how this algorithm can be implemented as a hardware solution, which alleviates the multicast HOL blocking issue by means of queue look-ahead. Simulation results demonstrate that this FIFO-based IQ multicast architecture is able to achieve significant improvements in terms of multicast latency requirements by searching through a small number of cells beyond the HOL cells in the input queues. Furthermore, hardware synthesis results show that the proposed algorithm can be very efficiently implemented in hardware to perform multicast scheduling at very high speeds with only modest resource requirements.

Low-Latency Multicast Scheduling in All-Optical Interconnects

Optical interconnects are considered as a very appealing solution for future high speed interconnections in core networks and parallel computers. In this paper, we study multicast scheduling in all-optical packet interconnects/switches. We first propose a novel optical buffer called multicast-enabled fiber-delay-lines (M-FDLs), which can provide flexible delay for copies of multicast packets using only a small number of FDL segments. We then present a Low Latency Multicast Scheduling (LLMS) Algorithm that considers the schedule of each arriving packet for multiple time slots. We show that LLMS has several desirable features, such as a guaranteed delay upper bound and adaptivity to transmission requirements. To relax the time constraint of LLMS, we further propose a pipeline and parallel architecture for LLMS that distributes the scheduling task to multiple pipelined processing stages, with N processing modules in each stage, where N is the size of the interconnect. Finally, by implementing it with simple combination circuits, we show that each processing module can complete the packet scheduling for a time slot in O(1) time. The performance of LLMS is evaluated extensively against statistical traffic models and real Internet traffic traces, and the results show that the proposed LLMS algorithm can achieve superior performance in terms of average packet delay and packet drop ratio.

High-Speed Multicast Scheduling in Hybrid Optical Packet Switches with Guaranteed Latency

In this paper, we study multicast scheduling in the OpCut switch, a recently proposed hybrid optical/electronic switching architecture for transmitting high-volume traffic in core networks and parallel computers. First, we present a multicast scheduling algorithm called Guaranteed Latency Multicast Scheduling (GLMS) that considers the schedule of each packet for multiple time slots. We show that GLMS has several desirable features, such as guaranteed latency for all transmitted packets and adaptivity to transmission requirements. To relax the time constraint on computing a schedule, we further propose a parallel and pipeline processing architecture for GLMS that distributes the scheduling task to multiple pipelined processing stages, with N processors in each stage, where N is the switch size. Finally, by implementing it with simple combination logic circuits, we show that each processor can finish the scheduling for one time slot in (O(1)time complexity. We evaluate the performance of GLMS extensively against statistical traffic models and real Internet traffic, and the results show that the proposed GLMS algorithm can achieve very low average packet latency with minimum packet drop ratio.

A Fan-out Splitting Scheduling Algorithm with QoS Difference for Optical Multicast Packet Switching Node

Abstract To improve the optical multicast packet switching node throughput performance, the new multicast scheduling algorithms are need urgently to overcome the entire optical multicast packet discard under the model of “one-shot”. A novel QoS difference optical multicast scheduling algorithm, which supporting the fan-out splitting for optical multicast packet switching node with limited range wavelength converter shared per node and without optical random access memory, is presented in the paper. By dropping partly not all the optical multicast packets which are replicated in the blocking multicast source, the proposed algorithm can improve output port utilization. Moreover, the algorithm is improved to provide service QoS difference for priority different traffic application. The simulation results show that the proposed algorithms remarkably improve the throughput of optical multicast packet switch node in comparison with the existing algorithms and support high priority service with high throughput QoS.

Integrated power‐saving scheduling algorithm in IEEE 802.16e networks

In IEEE 802.16e networks, with the popularisation of multimedia services, multicast and unicast services can coexist in one mobile subscriber station (MSS). The mobile devices are generally powered by battery, which is limited in energy. Thus, power saving is an important issue to be considered for extending the lifetime of the MSSs. The authors have proposed a multicast services-based scheduling (MSBS) algorithm that improves the energy efficiency of both unicast and multicast services, while satisfying the quality of service requirements of the MSSs in 802.16e wireless networks. MSBS schedules the packets in such a way that each packet is transmitted before its deadline and the energy consumed by the MSSs is reduced by minimising the number of state transitions by the MSSs. The simulation results show that MSBS can produce significant overall energy-saving and prolonged lifetime as compared to other scheduling schemes in 802.16e wireless networks.

Multicast scheduling algorithm supporting spatial mini-slot reuse for IEEE 802.16 mesh networks

In this paper, we propose a mechanism for multicast data transmission in IEEE 802.16 mesh networks aimed at increasing the throughput by incorporating mini-slot spatial reuse. The proposed mechanism includes two novel algorithms: a source-based multicast tree topology construction algorithm followed by an interference-aware multicast scheduling algorithm. The proposed multicast interference-aware scheduling algorithm can be applied to both source-based and rendezvous-based multicast tree topologies. Results of our simulation study show that in comparison to the mechanism used for the IEEE 802.16's standard, the proposed multicast tree generation algorithm reduces the number of consumed mini-slots by 64% on average. Moreover, using the proposed interference-aware scheduling algorithm decreases the number of required mini-slots by a further 22% on average. Therefore, the proposed multicast scheduling mechanism shows a higher throughput than the previous approaches and it is more scalable with respect to increasing the number of multicast groups as well as increasing the number of members inside each multicast group.

Multicast Scheduling and Resource Allocation Algorithms for OFDMA-Based Systems: A Survey

Multicasting is emerging as an enabling technology for multimedia transmissions over wireless networks to support several groups of users with flexible quality of service (QoS) requirements. Although multicast has huge potential to push the limits of next generation communication systems; it is however one of the most challenging issues currently being addressed. In this survey, we explain multicast group formation and various forms of group rate determination approaches. We also provide a systematic review of recent channel-aware multicast scheduling and resource allocation (MSRA) techniques proposed for downlink multicast services in OFDMA based systems. We study these enabling algorithms, evaluate their core characteristics, limitations and classify them using multidimensional matrix. We cohesively review the algorithms in terms of their throughput maximization, fairness considerations, performance complexities, multi-antenna support, optimality and simplifying assumptions. We discuss existing standards employing multicasting and further highlight some potential research opportunities in multicast systems.

Multicast Support in Input Queued Switches with Low Matching Overhead

This letter addresses the scalability problems induced by high complexity of multicast scheduling algorithms in high-speed switches. Based on a two-phase (request-grant) scheduling scheme in a Nx N switch, a more scalable approach instead of traditional iterative schedulings is presented, which reduces the matching overhead from O(kN) to O(N) by selecting one head-of-line cell for requesting when k multicast queues are allocated at each input port. Simulation results show that the proposed algorithm exhibits a good switching performance in terms of throughput and average delay under various traffic patterns.

Integration of unicast and multicast scheduling in a two-stage switch architecture with low scheduling overhead

This study deals with the scalability problems induced by high complexity of integrated scheduling for high-speed switches, and presents a simple two-stage integrated scheduling algorithm that supports both unicast and multicast traffic simultaneously. The first stage of the switching fabric performs switching for unicast traffic and load-balancing for multicast traffic, whereas the second stage performs switching for multicast traffic with a new multicast scheduling algorithm to reduce the multicast head-of-line (HoL) blocking problem. Considering the tradeoff balancing complexity and performance, the proposed integrated algorithm performs without iteration, and reduces the scheduling overhead from traditional O(kN) to O(N) with a two-phase (request-grant) scheduling for unicast and multicast traffic at each stage. Simulation results show that the proposed integrated algorithm exhibits a good performance in terms of throughput and average delay, at different traffic compositions under various traffic patterns, especially with non-uniform traffic.

PWBA: A Novel Multicast Scheduling Algorithm for Wideband Multimedia Satellite Communications

Satellite multicast service expands the application of wideband multimedia satellite. Scheduling plays an important role to guarantee Quality of Service (QoS) for wideband multimedia multicast services. In this paper, considering various properties of QoS requirements of latency, throughput and priority, a PWBA multicast scheduling algorithm is proposed to balance trade-off between throughput and latency in order to providing better multimedia services in satellite networks. Comparing with the WBA and PGMF multicast scheduling policies, the proposed PWBA has better performances in both latency and throughput.

Enhanced first-in-first-out-based round-robin multicast scheduling algorithm for input-queued switches

This study focuses on the multicast scheduling for M×N input-queued switches. An enhanced first-in-first-out -based round-robin multicast scheduling algorithm is proposed with a function of searching deeper into queues to reduce the head-of-line (HOL) blocking problem and thereby the multicast latency. Fan-out information of each input cell composes a traffic matrix and the scheduler executes a round-robin algorithm on each column independently. Scheduling decisions result in a decision matrix for the scheduler to release multicast cells accordingly. A matrix operation called sync is carried out on the decision matrix to reduce the number of transmission for each cell. To reduce the HOL blocking problem, a complement matrix is constructed based on the traffic matrix and the decision matrix, and a process of searching deeper into the queues is carried out to find cells that can be sent to the idle outputs. Simulation results show that the proposed function of searching deeper into the queues can alleviate the HOL blocking and as a result reduce the multicast latency significantly. Under both balanced and unbalanced multicast traffic, the proposed algorithm is able to maintain a stable throughput.

Bandwidth Guaranteed Multicast Scheduling for Buffered Crossbar

The limitations in complexities and extensibilities of current scheduling policies based on combined input and cross-point queuing switch (CICQ) are first analyzed. To overcome the deficiencies in supporting fair and QOS scheduling, we propose a fair and simple high-performance multicast scheduling algorithm for Combined Input Crosspoint Queued Switches, which is called multicast Fair Service and Group Smoothed Round Robin (mFGSR). The complexity of the algorithm is onlyO(1).mFGSR groups and schedules flows according to the weight of flows, thus it has good fairness and can adapt to the need of real-time performance. Theorotical analysis and simulation results show that mFGSR exhibits good delay, throughput and anti-burst performance.