In this letter, we propose a novel dynamic channel assignment scheme considering interference mitigation to improve the downlink system performance for femtocell networks based on OFDMA. The proposed scheme consists o...
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In this letter, we propose a novel dynamic channel assignment scheme considering interference mitigation to improve the downlink system performance for femtocell networks based on OFDMA. The proposed scheme consists of two steps: the first step aims to group femtocell access points (FAPs) using graph coloring algorithm while the second step dynamically assigns channels according to the channel state of femtocell user equipments (FUEs). Through simulation results, we show that the proposed scheme outperforms other schemes in terms of mean FUE capacity and probability of FUEs which have capacities less than a given FUE traffic load.
Optical multistage interconnection networking presents different and interesting challenges to the study of multicasting or the more dense collective communication problem of electronic counterparts, because of a diff...
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ISBN:
(纸本)0889865442
Optical multistage interconnection networking presents different and interesting challenges to the study of multicasting or the more dense collective communication problem of electronic counterparts, because of a different undesired coupling of two signals within a switching element and of a demand for higher speed processing. That is, an efficient routing process through an optical network while avoiding "crosstalk" is required, and this can be achieved by minimizing total processing time (initial route computing time and real routing time). The former factor is to determine a routing algorithm whose time complexity is the minimum. The latter one is to determine the optimum routing by which all data can be routed from the inputs to the appropriate outputs in the minimum number of passes through the network. These two factors are in counterpoint to each other. In this paper, first, one approach (named source-order routing) for minimizing the total processing time required in multicasting communication, based on the greedy method, is examined by comparing it with two other approaches;a heuristic graph coloring algorithm and the Odd-Even algorithm. Next, all-to-all personalized communication is taken up as the most densely collective communication, and this communication algorithm with single-fault-tolerant capability is investigated.
With the help of computer algorithms, we improve the lower bound on the edge Folkman number F-e(3, 3;5) and vertex Folkman number F-v(3, 3;4), and, thus, show that the exact values of these numbers are 15 and 14, resp...
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With the help of computer algorithms, we improve the lower bound on the edge Folkman number F-e(3, 3;5) and vertex Folkman number F-v(3, 3;4), and, thus, show that the exact values of these numbers are 15 and 14, respectively. We also present computer enumeration of all critical graphs. (C) 1999 John Wiley & Sons, Inc.
In a distributed computing environment, a highperformance communication network is essential. In this paper, we present a dynamically partitionable circular bus network (PCBN) and efficient algorithms for maximizing i...
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In a distributed computing environment, a highperformance communication network is essential. In this paper, we present a dynamically partitionable circular bus network (PCBN) and efficient algorithms for maximizing its utilization. In our approach, a distributed network is transformed into a graph, in which a vertex represents a communication request and an edge denotes the conflict between a pair of communication requests. A graph traversal algorithm is then applied to the graph to identify some maximal independent sets of vertices, The communication requests corresponding to the vertices of a maximal independent set can proceed in parallel. By computing the expected size of the maximal independent sets of a graph, we can obtain the improvement ratio of the network. In this paper, the network control and synchronization techniques of PCBN are described in detail. Another problem dealt with in this paper is the idling problem in the execution of nonconflicting requests. Since the requests may take different amounts of time to execute, the subnetworks of shorter durations will be idle after the completion of their requests if subnetworks are assigned to process them to their completion. This bus idling problem is solved by using a coin-changing algorithm. The performance evaluation shows a significant decrease in network delay.
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