Broadcast Algorithm Research Articles

Collision Optimized Broadcast Scheduling in Wireless Sensor Network

Broadcasting plays an important role in the communication protocol design and it acts as a fundamental operation in wireless sensor network (WSN). This paper investigates the Minimum Latency Broadcast Scheduling in Duty Cycled (MLBSDC) problem in WSN. The MLBSDC problem aims to find a broadcast scheduling that minimizes the time in which the last node receives the broadcast message with minimum collision. The focus is mainly on providing minimum collision and finding the lower bound of broadcast latency. In this paper, a novel algorithm Collision Optimized Broadcast Scheduling (COBS) is proposed which is a refinement of Effective Broadcast Scheduling with Optimized Latency (EBSOL) [9] algorithm. COBS allow nodes in different layers of the broadcast tree to transmit the message simultaneously. In EBSOL, the latency is efficiently reduced by layer by layer approach and the broadcast tree is constructed. It is proved that COBS produces a latency of at most 12 |T|, where T denotes the number of time slots in a scheduling period. To prevent collision, each node maintains an effective routing table and only one parent node transmits the message to the child node. The results from extensive simulation show that COBS has a better performance than the existing One To All Broadcast (OTAB) algorithm in terms of reduction in latency, number of transmission and collision.

MPI and UPC broadcast, scatter and gather algorithms in Xeon Phi

SummaryAccelerators have revolutionised the high performance computing (HPC) community. Despite their advantages, their very specific programming models and limited communication capabilities have kept them in a supporting role of the main processors. With the introduction of Xeon Phi, this is no longer true, as it can be programmed as the main processor and has direct access to the InfiniBand network adapter. Collective operations play a key role in many HPC applications. Therefore, studying its behaviour in the context of manycore coprocessors has great importance. This work analyses the performance of different algorithms for broadcast, scatter and gather, in a large‐scale Xeon Phi supercomputer. The algorithms evaluated are those available in the reference message passing interface (MPI) implementation for Xeon Phi (Intel MPI), the default algorithm in an optimised MPI implementation (MVAPICH2‐MIC), and a new set of algorithms, developed by the authors of this work, designed with modern processors and new communication features in mind. The latter are implemented in Unified Parallel C (UPC), a partitioned global address space language, leveraging one‐sided communications, hierarchical trees and message pipelining. This study scales the experiments to 15360 cores in the Stampede supercomputer and compares the results to Xeon and hybrid Xeon + Xeon Phi experiments, with up to 19456 cores. Copyright © 2015 John Wiley & Sons, Ltd.

Topology-oblivious optimization of MPI broadcast algorithms on extreme-scale platforms

Significant research has been conducted in collective communication operations, in particular in MPI broadcast, on distributed memory platforms. Most of the research efforts aim to optimize the collective operations for particular architectures by taking into account either their topology or platform parameters. In this work we propose a simple but general approach to optimization of the legacy MPI broadcast algorithms, which are widely used in MPICH and Open MPI. The proposed optimization technique is designed to address the challenge of extreme scale of future HPC platforms. It is based on hierarchical transformation of the traditionally flat logical arrangement of communicating processors. Theoretical analysis and experimental results on IBM BlueGene/P and a cluster of the Grid’5000 platform are presented.

On the scalability and message count of Trickle-based broadcasting schemes

As the use of wireless sensor networks increases, the need for efficient and reliable broadcasting algorithms grows. Ideally, a broadcasting algorithm should have the ability to quickly disseminate data, while keeping the number of transmissions low. In this paper, we analyze the popular Trickle algorithm, which has been proposed as a suitable communication protocol for code maintenance and propagation in wireless sensor networks. We show that the broadcasting process of a network using Trickle can be modeled by a Markov chain and that this chain falls under a class of Markov chains, closely related to residual lifetime distributions. It is then shown that this class of Markov chains admits a stationary distribution of a special form. These results are used to analyze the Trickle algorithm and its message count. Our results prove conjectures made in the literature concerning the effect of a listen-only period. Besides providing a mathematical analysis of the algorithm, we propose a generalized version of Trickle, with an additional parameter defining the length of a listen-only period.

On All-to-All Broadcast in Dense Gaussian Network On-Chip

Gaussian networks are gaining popularity as good candidates Network On-Chip (NoC) for interconnecting Multiprocessor System-on-Chips (MPSoCs). They showed better topological properties compared to the 2D torus networks with the same number of nodes $N$ and the same degree 4. All-to-all broadcast is a collective communication algorithm used frequently in many parallel applications. Recently, Z. Zhang et al. [1] have proposed an all-to-all broadcast algorithm for Gaussian on-chip networks that achieves the minimum delay time but requires 4 $k$ extra buffers per router, where $k$ is the network diameter. In this paper, we propose a new all-to-all broadcast algorithm for dense Gaussian on-chip networks that achieves the minimum delay time without requiring any extra buffers per router. In this paper, we propose a new all-to-all broadcast algorithm for dense Gaussian on-chip networks that achieves the minimum delay time without requiring any extra buffers per router. Along with low latency, reducing the amount of buffer space and power consumption are very important issues in NoCs architectures.

A distributed broadcast algorithm for duty-cycled networks with physical interference model

Broadcast is a fundamental operation in multi-hop wireless networks. Given a source node with a message to broadcast, the objective is to propagate the message to all nodes in an interference-free manner while incurring minimum latency. This problem, called Minimum-Latency Broadcast Scheduling (MLBS), has been studied extensively in wireless networks whereby nodes remain on all times and has been shown to be NP-hard. However, only a few studies have addressed this problem in the context of duty-cycled wireless networks, which unfortunately, remains NP-hard. In these networks, nodes do not wake up simultaneously, and hence, not all neighbors of a transmitting node will receive a broadcast message at the same time, meaning multiple transmissions may be necessary. Moreover, most of these studies addressed the MLBS problem over the idealistic protocol interference model. Henceforth, this paper considers MLBS for duty-cycled wireless networks under the physical interference model and presents an approximation algorithm called hexagon-based broadcast algorithm (HBA), which has a constant ratio in terms of broadcast latency and transmission times. We have evaluated HBA in different network configurations, and the results show that the latencies achieved by our algorithm are much lower than existing schemes. In particular, HBA manages to half the broadcast latency achieved by the state-of-the-art tree-based algorithm.

Broadcasting in ad hoc multiple access channels

We study broadcast in multiple access channels in dynamic adversarial settings. There is an unbounded supply of anonymous stations attached to a synchronous channel. There is an adversary who injects packets into stations to be broadcast on the channel. The adversary is restricted by injection rate, burstiness, and by how many passive stations can be simultaneously activated by providing them with packets. We consider deterministic distributed broadcast algorithms, which are further categorized by their properties. We investigate for which injection rates can algorithms attain bounded packet latency, when adversaries are restricted to be able to activate at most one station per round. The rates of algorithms we present make the increasing sequence consisting of 13, 38 and 12, reflecting the additional features of algorithms. We show that injection rate 34 cannot be handled with bounded packet latency.

τ-Lop: Modeling performance of shared memory MPI

We present a performance model for representing and predicting cost of parallel algorithms.Model goal is to help in the design and optimization of parallel collective algorithms.It is applied to collective algorithms in mainstream MPI implementations in shared memory.Model is compared to other well known and established models. Formal modeling of the cost of MPI primitives allows a machine independent representation, comparison and performance analysis of their underlying algorithms. Current accepted methods are all the off-springs of LogP, conceived to model the cost of inter-node point-to-point messages in networks of single-processor machines. As new supercomputers are built upon cheap commodity boards with a growing number of cores accessing hierarchical memories, intra-node communication becomes progressively more relevant. Techniques for shared memory communication, such as message segmentation and collectives, not based on point-to-point operations, are substantively different from their inter-node counterparts. This paper unveils the reasons for the poor fit of LogGP and the most recent models in this domain, log n P and m log n P , and proposes a new model named ? -Lop, rooted on them, but addressing the challenge of accurately modeling shared memory MPI communications. Broadcast algorithms of mainstream MPI implementations, MPICH and Open MPI, are modeled and analyzed.

On the Complexity of Universal Leader Election

Electing a leader is a fundamental task in distributed computing. In its implicit version, only the leader must know who is the elected leader. This article focuses on studying the message and time complexity of randomized implicit leader election in synchronous distributed networks. Surprisingly, the most “obvious” complexity bounds have not been proven for randomized algorithms. In particular, the seemingly obvious lower bounds of Ω( m ) messages, where m is the number of edges in the network, and Ω( D ) time, where D is the network diameter, are nontrivial to show for randomized (Monte Carlo) algorithms. (Recent results, showing that even Ω( n ), where n is the number of nodes in the network, is not a lower bound on the messages in complete networks, make the above bounds somewhat less obvious). To the best of our knowledge, these basic lower bounds have not been established even for deterministic algorithms, except for the restricted case of comparison algorithms, where it was also required that nodes may not wake up spontaneously and that D and n were not known. We establish these fundamental lower bounds in this article for the general case, even for randomized Monte Carlo algorithms. Our lower bounds are universal in the sense that they hold for all universal algorithms (namely, algorithms that work for all graphs), apply to every D , m , and n , and hold even if D , m , and n are known, all the nodes wake up simultaneously, and the algorithms can make any use of node's identities. To show that these bounds are tight, we present an O ( m ) messages algorithm. An O ( D ) time leader election algorithm is known. A slight adaptation of our lower bound technique gives rise to an Ω( m ) message lower bound for randomized broadcast algorithms. An interesting fundamental problem is whether both upper bounds (messages and time) can be reached simultaneously in the randomized setting for all graphs. The answer is known to be negative in the deterministic setting. We answer this problem partially by presenting a randomized algorithm that matches both complexities in some cases. This already separates (for some cases) randomized algorithms from deterministic ones. As first steps towards the general case, we present several universal leader election algorithms with bounds that tradeoff messages versus time. We view our results as a step towards understanding the complexity of universal leader election in distributed networks.

Collective Algorithms for Multiported Torus Networks

Modern supercomputers with torus networks allow each node to simultaneously pass messages on all of its links. However, most collective algorithms are designed to only use one link at a time. In this work, we present novel multiported algorithms for the scatter, gather, all-gather, and reduce-scatter operations. Our algorithms can be combined to create multiported reduce, all-reduce, and broadcast algorithms. Several of these algorithms involve a new technique where we relax the MPI message-ordering constraints to achieve high performance and restore the correctordering using an additional stage of redundant communication. According to our models, on an n -dimensional torus, our algorithms should allow for nearly a 2 n -fold improvement in communication performance compared to known, single-ported torus algorithms. In practice, we have achieved nearly 6x better performance on a 32k-node 3-dimensional torus.

Exploiting Multiple Channels for Low Latency and Semireliable Broadcasting in Cognitive Wireless Sensor Networks

In Wireless Sensor Networks (WSNs), disaster management is a crucial issue that focuses on disaster relief and recovery. Mobile sensor nodes support disaster relief and recovery by means of real-time bidirectional communication. For its high data rate requirement, IEEE 802.11 specification can be used for the radio interface of sensor nodes, and the nodes can be equipped with multiple 802.11 radios to utilize multiple channels and link data rates. Channel assignment algorithms can be applied in cognitive radio enabled networks which performs dynamic channel configuration for utilizing multiple channels. For efficient and semireliable broadcast in cognitive radio WSNs, we focus on reducing broadcast latency and achieving 100% delivery percentage. To realize these goals, in this study, we present our design for a novelChannel Assignment Algorithm for a Collision-Reduced Broadcast Tree(CA-CBT). Fundamentally, CA-CBT builds a broadcast tree and then uses several heuristic procedures to allocate collision-free channels to links on the tree. If CA-CBT fails to allocate collision-free channels due to a limited number of available channels, it allocates non-collision-free channels with the smallest number of interfering nodes. Through extensive simulations, we demonstrated that CA-CBT supports lower broadcast latency and higher delivery percentages compared with existing broadcast algorithms.

Performance Improvement of Topology-Transparent Broadcast Scheduling in Mobile Ad Hoc Networks

Broadcasting is a key function in mobile ad hoc networks. Topology-dependent scheduling algorithms depend on the detailed network connectivity information and cannot adapt to dynamic topological changes in mobile networks. To overcome this limitation, topology-transparent broadcast scheduling algorithms have been proposed. Due to the large overhead of implement- ing the acknowledgement mechanism in broadcast communica- tions and to guarantee that there is at least one collision-free transmission in each frame, most existing topology-transparent broadcast scheduling algorithms require a node to transmit the same packet repeatedly at multiple slots during one frame. This is very inefficient. In this paper, we propose an efficient topology- transparent broadcast scheduling algorithm. First, instead of transmitting the same packet repeatedly during one frame, each node collects transmission codes of its two-hop neighbors and transmits several different packets during one frame. Second, noting that many unassigned slots are not utilized, we propose several methods to utilize the unassigned slots efficiently in a collision-free and traffic-adaptive manner. Thus, our algorithm provides a guaranteed throughput and achieves a much better average throughput. The analytical and simulation results show that our proposed algorithm outperforms other existing topology- transparent broadcast algorithms dramatically.

Convergecast and Broadcast by Power-Aware Mobile Agents

A set of identical, mobile agents is deployed in a weighted network. Each agent has a battery—a power source allowing it to move along network edges. An agent uses its battery proportionally to the distance traveled. We consider two tasks: convergecast, in which at the beginning, each agent has some initial piece of information, and information of all agents has to be collected by some agent; and broadcast in which information of one specified agent has to be made available to all other agents. In both tasks, the agents exchange the currently possessed information when they meet. The objective of this paper is to investigate what is the minimal value of power, initially available to all agents, so that convergecast or broadcast can be achieved. We study this question in the centralized and the distributed settings. In the centralized setting, there is a central monitor that schedules the moves of all agents. In the distributed setting every agent has to perform an algorithm being unaware of the network. In the centralized setting, we give a linear-time algorithm to compute the optimal battery power and the strategy using it, both for convergecast and for broadcast, when agents are on the line. We also show that finding the optimal battery power for convergecast or for broadcast is NP-hard for the class of trees. On the other hand, we give a polynomial algorithm that finds a 2-approximation for convergecast and a 4-approximation for broadcast, for arbitrary graphs.In the distributed setting, we give a 2-competitive algorithm for convergecast in trees and a 4-competitive algorithm for broadcast in trees. The competitive ratio of 2 is proved to be the best for the problem of convergecast, even if we only consider line networks. Indeed, we show that there is no ( $$2-\epsilon $$ )-competitive algorithm for convergecast or for broadcast in the class of lines, for any $$\epsilon >0$$ .

Interconnection Networks of Degree Three Obtained by Pruning Two-Dimensional Tori

We study an interconnection network that we call <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$3Torus(m,n)$</tex> </formula> obtained by pruning the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$4m \times 4n$</tex> </formula> torus (of links) so that the resulting network is regular of degree 3. We show that <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$3Torus(m,n)$</tex> </formula> retains many of the useful properties of tori (although, of course, there is a price to be paid due to the reduction in links). In particular, we show that <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$3Torus(m,n)$</tex> </formula> is node-symmetric; we establish closed-form expressions on the length of a shortest path joining any two nodes of the network; we calculate the diameter precisely; we obtain an upper bound on the average inter-node distance; we develop an optimal distributed routing algorithm; we prove that <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$3Torus(m,n)$</tex> </formula> has connectivity 3 and is Hamiltonian; we obtain a precise expression for (an upper bound on) the wide-diameter; and we derive optimal one-to-all broadcast and personalized one-to-all broadcast algorithms under both a one-port and all-port communication model. We also undertake a preliminary performance evaluation of our routing algorithm. In summary, we find that <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$3Torus(m,n)$</tex> </formula> compares very favourably with tori.

Performance analysis of an extended grid based broadcast algorithm in mobile ad-hoc networks

In this paper we proposed a new extended grid-based broadcasting algorithm (EGBB) in mobile ad-hoc networks (MANETs) which reduces considerably the broadcast storm problem. EGBB algorithm is based on a logical 2-dimensional grid cells view of the geographical region of the MANET. EGBB algorithm minimizes the number of rebroadcasts by using gateway nodes for each grid cell, where only gateway nodes are responsible for rebroadcasting the message in order to solve network congestion problem. We extended the neighborhood of a node in a grid cell from the nodes located in only eight adjacent grid cells as originally in grid based broadcast (GBB) to any node in any grid cell within the node's transmission range to increase the reachability and reduce the number of hops. We also added a new adaptive feature to suite different traffic load and mobility conditions. We developed a simulation model based on NS2 simulator to measure the performance of EGBB and compare the results with the GBB; the efficient counter based scheme (ECB); and the position-aware counter-based algorithm (PCB). The simulation experiments showed good results for our new algorithm EGBB. EGBB outperforms GBB, ECB and PCB in terms of end-to-end delay, number of saved rebroadcasts, and packet collision ratio under different traffic load, network density, and mobility conditions.

Some Results of Bondage Number of (n,k)-Star Graphs

In the computer network, bondage number is one of the most important parameters to measure the control theory of the computer network, denoted by b(G) for a network graph G. But predecessors have proved that computing them are very hard. So computing b(G) of some particular known gr-aphs is extremely valuable. In this paper, we determine b(S n,2 ) and the precise lowerbound of b(G) of (n,k)-star graphs, denoted by S n,k followed by some relative conclusions of n-star, denoted by S n as the isomorphism of S n,n-1 . In addition, our method giving dominating set of S n,k is easily understood, which presented a broadcast algorithm to determine dominating set of S n,k . DOI: http://dx.doi.org/10.11591/telkomnika.v11i9.3285

A Novel Geo-Broadcast Algorithm for V2V Communications over WSN

The key for enabling the next generation of advanced driver assistance systems (ADAS), the cooperative systems, is the availability of vehicular communication technologies, whose mandatory installation in cars is foreseen in the next few years. The definition of the communications is in the final step of development, with great efforts on standardization and some field operational tests of network devices and applications. However, some inter-vehicular communications issues are not sufficiently developed and are the target of research. One of these challenges is the construction of stable networks based on the position of the nodes of the vehicular network, as well as the broadcast of information destined to nodes concentrated in a specific geographic area without collapsing the network. In this paper, a novel algorithm for geo-broadcast communications is presented, based on the evolution of previous results in vehicular mesh networks using wireless sensor networks with IEEE 802.15.4 technology. This algorithm has been designed and compared with the IEEE 802.11p algorithms, implemented and validated in controlled conditions and tested on real vehicles. The results suggest that the characteristics of the designed broadcast algorithm can improve any vehicular communications architecture to complement a geo-networking functionality that supports a variety of ADAS.

Exponential replicate broadcasting mechanism for adaptive bandwidth allocation in mobile networks

Abstract This paper proposes an exponential replicate broadcasting (ERB) algorithm for data dissemination to improve data access efficiency. The proposed ERB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive the mean access latency of the generated broadcast program. In light of the derived results, both the index channel's bandwidth and the data channel's bandwidth can be optimally allocated to maximize bandwidth utilization. This paper presents experiments to help evaluate the effectiveness of the proposed strategy. From the experimental results, it can be seen that the proposed mechanism is feasible in practice.

Coding Opportunity Aware Backbone Metrics for Broadcast in Wireless Networks

Reducing transmission redundancy is key to efficient broadcast in wireless networks. A standard approach to achieving this goal is to create a network backbone consisting of a subset of nodes that are responsible for data forwarding, while other nodes act as passive receivers. On top of this, network coding (NC) is often used to further reduce unnecessary transmissions. The main problem with existing backbone and NC combinations is that the backbone construction process is blind of what is needed by NC, thus may produce a structure that limits the power of NC algorithms. To address this problem, we propose Coding Opportunity Aware Backbone (COAB) metrics, which seek to maximize coding opportunities when selecting backbone forwarders. We show that the backbone construction process guided by our metrics leads to significantly increased coding frequency, at the cost of minimal localized information exchange. The highlight of our work is COAB's broad applicability and effectiveness. We integrate the COAB metrics with ten state-of-the-art broadcast algorithms specified in eight publications [1]-[8], and evaluate COAB with a running testbed of 30 MICAz nodes and extensively simulations. The experimental results show that our design outperforms the existing schemes substantially.

Distributed multiple-message broadcast in wireless ad hoc networks under the SINR model

In a multiple-message broadcast, an arbitrary number of messages originate at arbitrary nodes in the network at arbitrary times. The problem is to disseminate all these messages to the whole network. This paper gives the first randomized distributed multiple-message broadcast algorithm with worst-case performance guarantee in wireless ad hoc networks employing the SINR interference model which takes interferences from all the nodes in the network into account. The network model used in this paper also considers the harsh characteristics of wireless ad hoc networks: there is no prior structure, and nodes cannot perform collision detection and have little knowledge of the network topology. Under all these restrictions, our proposed randomized distributed multiple-message broadcast protocol can deliver any message m to all nodes in the network in O(D+k+log2⁡n) timeslots with high probability, where D is the network diameter, k is the number of messages whose broadcasts overlap with m, and n is the number of nodes in the network. We also study the lower bound for randomized distributed multiple-message broadcast protocols. In particular, we prove that any uniform randomized algorithm needs Ω(D+k+log2⁡nlog⁡log⁡log⁡n) timeslots to disseminate k messages initially stored at k nodes.