Use Of Multicast Communications Research Articles

An efficient scheduling algorithm for dataflow architecture using loop-pipelining

Dataflow architecture has native advantages in achieving high instruction parallelism and power efficiency for today’s emerging applications such as high performance computing and deep neural network. In dataflow computing, the execution of instructions is driven by data, so the data transfer efficiency of the network on chip (NoC) is a key factor affecting performance. However, the NoC performance degrades due to the increasing use of multicast communications in many applications. The existing dataflow architecture instruction scheduling algorithms do not optimize multicast communication between the instruction and its successor instructions, so the routing paths of many multicast packets have forks which cause bandwidth waste and potential network congestion. We propose a sharing path awareness (SPA) algorithm to optimize multicast communication in the dataflow architecture. The algorithm shares the routing paths from the instruction to its child node to reduce the NoC bandwidth waste through the instruction scheduler. For applications using software iteration, we further extend the loop optimization to the SPA algorithm to sufficiently exploit instruction-level parallelism. Compared with the state-of-the-art algorithm, we show that the SPA algorithm achieves 20.21% average performance improvement and 15.11% energy consumption reduction for our experimental workloads.

Energy Efficient Power and Channel Allocation in Underlay Device to Multi Device Communications

In this paper, we optimize the energy efficiency (bits/s/Hz/J) of device-to-multi-device (D2MD) wireless communications. While the device-to-device scenario has been extensively studied to improve the spectral efficiency in cellular networks, the use of multicast communications opens the possibility of reusing the spectrum resources also inside the groups. The optimization problem is formulated as a mixed integer non-linear joint optimization for the power control and allocation of resource blocks (RBs) to each group. Our model explicitly considers resource sharing by letting co-channel transmission over a RB (up to a maximum of r transmitters) and/or transmission through s different channels in each group. We use an iterative decomposition approach, using first matching theory to find a stable even if sub-optimal channel allocation, to then optimize the transmission power vectors in each group via fractional programming. Additionally, within this framework, both the network energy efficiency and the max-min individual energy efficiency are investigated. We characterize numerically the energy-efficient capacity region, and our results show that the normalized energy efficiency is nearly optimal (above 90 percent of the network capacity) for a wide range of minimum-rate constraints. This performance is better than that of other matching-based techniques previously proposed.

EMGR: Energy-efficient multicast geographic routing in wireless sensor networks

It is a quite common case for Wireless Sensor Networks (WSNs) in most application scenarios, that the same message needs to be sent to multiple destinations from a single sensor node. These applications can benefit from the use of multicast communications to conserve resource. Multicast geographic routing has recently been proposed as an efficient and scalable approach to fulfill this requirement by exploiting the location information of nodes instead of the global topology information to route multicast messages. As the sensor nodes are often powered by batteries and recharging them is infeasible, energy-efficient routing plays an important role towards the success of WSNs. In this paper, we address this challenging issue of WSNs and propose an energy-efficient multicast geographic routing protocol (EMGR) to achieve this goal. EMGR employs an energy-aware multicast tree, formed by the set of destinations and the source node based on the metric of energy over advance, to guide multicast message delivery and adaptively select the nodes closest to the energy-optimal relay location as the next forwarders for energy conservation. Analytic and simulation results demonstrate that our proposed protocol achieves the improved performance in terms of low energy consumption, control overhead, computational complexity, and high packet delivery ratio, compared to the existing protocols.

Resilient overlay network for real-time interactive multimedia sessions in corporate networks

Real-time interactive multimedia communications are becoming increasingly useful for education, business, e-commerce and e-government, providing an enriched user experience in teleconferencing, e-meetings, distance training and product demonstrations. Large corporations are usually located at several sites, so real-time multipoint sessions within corporations are especially difficult. IP multicast is available or feasible within each site of an organization. Thus, corporate networks can be considered as various multicast-capable networks interconnected through a wide area network without multicast connectivity. This paper proposes a resilient self-managed overlay network to support real-time multipoint interactive sessions within corporate networks. The proposed overlay takes advantage of the configuration of corporate networks to self-organize and provide an efficient media delivery service, making use of multicast communications wherever available. Various self-healing techniques are implemented allowing for the continuity of ongoing sessions in spite of network disruptions and entity failures. Extensive simulations and tests have been carried out to assess the performance and resilience of the overlay facing several types of disruptions.

Guest Editor's introduction: Special issue on distributed virtual environments

Guest Editor's introduction: Special issue on distributed virtual environments

Awareness-based communication management in the MASSIVE systems

The MASSIVE-1 and MASSIVE-2 distributed virtual environment systems are based on an explicit model of user communication requirements known as the spatial model of interaction; this model addresses the general issue of managing communication in large space-based systems such as DVEs. The goals of the spatial model are to guide the distribution and presentation of information in a way which facilitates collaboration between participants (based on observed patterns of interaction in real-world environments) and which is also efficient and appropriate. The MASSIVE-1 system emphasized the spatial model's `aura' concept as the basis for a distinct shared service in an otherwise wholly unicast peer-to-peer system. This approach was effective for relatively small systems but could not be extended to make general use of multicast communication (to reduce total bandwidth requirements). The MASSIVE-2 system added the concept of `third-party objects' which support the definition and management of multiple multicast groups for updates and continuous media distribution.

The use of multicast delivery to provide a scalable and interactive video-on-demand service

In typical proposals for video-on-demand (VoD) systems, customers are serviced individually by allocating and dedicating a transmission channel and a set of server resources to each customer. This approach leads to an expensive to operate, nonscalable system. We consider a VoD system that uses multicast delivery to service multiple customers with a single set of resources. The use of multicast communication requires that part of the on-demand nature of the system be sacrificed to achieve scalability and cost-effectiveness. One drawback to using multicast communication is that it complicates the provision or interactive VCR-style functions. Interactivity can be provided by either increasing the complexity of the customer set-top box (STB) or by modifying the semantics of the interactive functions to make them easier to provide. We describe a framework and mechanisms by which such interactive functions can be incorporated into a multicast delivery VoD system. Through the use of simulation, we evaluate and compare the performance of a unicast VoD system and multicast VoD systems offering various levels of interactivity.