Is Topology-Transparent Scheduling Really Inefficient in Static Multihop Networks?

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Topology-Transparent Broadcast Scheduling with Erasure Coding in Wireless Networks

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Adaptive topology-transparent distributed scheduling in wireless networks

Proceedings of the IEEE International Conference on Communications, 2010, p. 1-5Transmission scheduling is a key design problem in wireless multi-hop networks. Many transmission scheduling algorithms have been proposed to maximize the spatial reuse and minimize the time division multiple access (TDMA) frame length. Most of the scheduling algorithms are topology-dependent. They are generally graph-based and depend on the exact network topology information. Thus, they cannot adapt well to the dynamic wireless environment. In contrast, topology-transparent TDMA scheduling algorithms do not need detailed topology information. However, these algorithms offer very low minimum throughput. The objective of this work is to propose an adaptive topology-transparent scheduling algorithm to offer better throughput performance. With our algorithm, each node finds a transmission schedule so as to reduce the transmission conflicts and adapt better to the changing network environment. The simulation results show that the performance of our algorithm is better than the existing topology-transparent algorithms. ©2010 IEEE.published_or_final_versio

Topology-Transparent Scheduling in Mobile Ad Hoc Networks Supporting Heterogeneous Quality of Service Guarantees

Transmission scheduling plays a critical role in mobile ad hoc networks. Many transmission scheduling algorithms have been proposed to maximize the spatial reuse and minimize the time-division multiple-access (TDMA) frame length. Most algorithms require information on the network topology and cannot adapt to the dynamic topology in mobile scenarios. To overcome this limitation, topology-transparent scheduling algorithms have been proposed. Most of them, based on Galois field theory, Latin square, and block design theory, assign time slots to users and guarantee that there is at least one collision-free slot in each frame for each user. To the best of our knowledge, none of these topology-transparent algorithms support multiple quality of service (QoS) requirements. In this paper, we exploit the variable-weight optical orthogonal codes (VW-OOC) to design a topology-transparent scheduling algorithm in wireless ad hoc networks with multiple QoS levels. We study the performance, in terms of minimum guaranteed throughput and average throughput, of our proposed algorithm analytically and by extensive simulations.published_or_final_versio

TDMA scheduling design of multihop packet radio networks based on latin squares

Many transmission scheduling algorithms have been proposed to maximize the spatial reuse and minimize the time division multiple access (TDMA) frame length in multihop packet radio networks. Almost all existing algorithms assume exact network topology information and require recomputations when the network topology changes. In addition, existing work focuses on single channel TDMA systems. In this paper, we propose a multichannel topology-transparent algorithm based on latin squares. This algorithm has the flexibility to allow the growth of the network, i.e., the network can add more mobile nodes without recomputation of transmission schedules for existing nodes. At the same time, a minimum throughput is guaranteed. We analyze the efficiency of our algorithm, and examine the topology-transparent characteristics and the sensitivity on design parameters by simulation.published_or_final_versio

An optimal topology-transparent scheduling method in multihop packet radio networks

Many transmission scheduling algorithms have been proposed to maximize the spatial reuse and minimize the time-division multiple-access (TDMA) frame length in multihop packet radio networks. Almost all existing algorithms assume exact network topology information and do not adapt to different traffic requirements. Chlamtac and Farago proposed a topology-transparent algorithm. Following their approach, but with a different design strategy, we propose another algorithm which is optimal in that it maximizes the minimum throughput. We compare our algorithm with that of Chlamtac and Farago's and with the TDMA algorithm, and find that it gives better performance in terms of minimum throughput and minimum and maximum delay times. Our algorithm requires estimated values of the number of nodes and the maximum nodal degree in the network. However, we show that the performance of our algorithm is insensitive to these design parameters. © 1998 IEEE.published_or_final_versio

Neighbor Discovery Using Galois Fields and Its Hardware Implementation

Neighbor discovery is essential in all channel ac- cess protocols based on transmission scheduling, whether such protocols are topology-dependent or topology-independent. We propose a novel approach to neighbor discovery based on relative GPS coordinates (RGPS), extending the work by Chlamtac and Farago on topology-transparent transmission scheduling. The proposed approach attains neighbor discovery with timing guarantees, which yields greater scalability and requires smaller transmission compared to neighbor discovery mechanisms based on probabilistic methods. We further present the design and implementation of a hardware accelerator for evaluating the Galois field polynomials used in the proposed neighbor-discovery scheme

Chemical reaction optimization for task scheduling in grid computing

Grid computing solves high performance and high-throughput computing problems through sharing resources ranging from personal computers to supercomputers distributed around the world. One of the major problems is task scheduling, i.e., allocating tasks to resources. In addition to Makespan and Flowtime, we also take reliability of resources into account, and task scheduling is formulated as an optimization problem with three objectives. This is an NP-hard problem, and thus, metaheuristic approaches are employed to find the optimal solutions. In this paper, several versions of the Chemical Reaction Optimization (CRO) algorithm are proposed for the grid scheduling problem. CRO is a population-based metaheuristic inspired by the interactions between molecules in a chemical reaction. We compare these CRO methods with four other acknowledged metaheuristics on a wide range of instances. Simulation results show that the CRO methods generally perform better than existing methods and performance improvement is especially significant in large-scale applications. © 2011 IEEE.published_or_final_versio