Tuesday, June 21, 2011

Final Year Projects | IEEE Projects | Application Projects



Final Year Projects | IEEE Projects | Application Projects


Dynamic Conflict-Free Transmission Scheduling for Sensor Network Queries

Posted: 20 Jun 2011 11:50 PM PDT

With the emergence of high data rate sensor network applications, there is an increasing demand for high-performance query services. To meet this challenge, we propose Dynamic Conflict-free Query Scheduling (DCQS), a novel scheduling technique for queries in wireless sensor networks. In contrast to earlier TDMA protocols designed for general-purpose workloads, DCQS is specifically designed for query services in wireless sensor networks. DCQS has several unique features. First, it optimizes the query performance through conflict-free transmission scheduling based on the temporal properties of queries in wireless sensor networks. Second, it can adapt to workload changes without explicitly reconstructing the transmission schedule. Furthermore, DCQS also provides predictable performance in terms of the maximum achievable query rate. We provide an analytical capacity bound for DCQS that enables DCQS to handle overload through rate control. NS2 simulations demonstrate that DCQS significantly outperforms a representative TDMA protocol (DRAND) and 802.11b in terms of query latency and throughput.


Approaching Throughput-Optimality in Distributed CSMA Scheduling Algorithms With Collisions

Posted: 20 Jun 2011 11:50 PM PDT

It was shown recently that carrier sense multiple access (CSMA)-like distributed algorithms can achieve the maximal throughput in wireless networks (and task processing networks) under certain assumptions. One important but idealized assumption is that the sensing time is negligible, so that there is no collision. In this paper, we study more practical CSMA-based scheduling algorithms with collisions. First, we provide a Markov chain model and give an explicit throughput formula that takes into account the cost of collisions and overhead. The formula has a simple form since the Markov chain is "almost" time-reversible. Second, we propose transmission-length control algorithms to approach throughput-optimality in this case. Sufficient conditions are given to ensure the convergence and stability of the proposed algorithms. Finally, we characterize the relationship between the CSMA parameters (such as the maximum packet lengths) and the achievable capacity region.


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Final Year Projects | IEEE Projects | Application Projects

Tuesday, June 21, 2011

Final Year Projects | IEEE Projects | Application Projects


Dynamic Conflict-Free Transmission Scheduling for Sensor Network Queries

Posted: 20 Jun 2011 11:50 PM PDT

With the emergence of high data rate sensor network applications, there is an increasing demand for high-performance query services. To meet this challenge, we propose Dynamic Conflict-free Query Scheduling (DCQS), a novel scheduling technique for queries in wireless sensor networks. In contrast to earlier TDMA protocols designed for general-purpose workloads, DCQS is specifically designed for query services in wireless sensor networks. DCQS has several unique features. First, it optimizes the query performance through conflict-free transmission scheduling based on the temporal properties of queries in wireless sensor networks. Second, it can adapt to workload changes without explicitly reconstructing the transmission schedule. Furthermore, DCQS also provides predictable performance in terms of the maximum achievable query rate. We provide an analytical capacity bound for DCQS that enables DCQS to handle overload through rate control. NS2 simulations demonstrate that DCQS significantly outperforms a representative TDMA protocol (DRAND) and 802.11b in terms of query latency and throughput.


Approaching Throughput-Optimality in Distributed CSMA Scheduling Algorithms With Collisions

Posted: 20 Jun 2011 11:50 PM PDT

It was shown recently that carrier sense multiple access (CSMA)-like distributed algorithms can achieve the maximal throughput in wireless networks (and task processing networks) under certain assumptions. One important but idealized assumption is that the sensing time is negligible, so that there is no collision. In this paper, we study more practical CSMA-based scheduling algorithms with collisions. First, we provide a Markov chain model and give an explicit throughput formula that takes into account the cost of collisions and overhead. The formula has a simple form since the Markov chain is "almost" time-reversible. Second, we propose transmission-length control algorithms to approach throughput-optimality in this case. Sufficient conditions are given to ensure the convergence and stability of the proposed algorithms. Finally, we characterize the relationship between the CSMA parameters (such as the maximum packet lengths) and the achievable capacity region.


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