Tài liệu Sổ tay của các mạng không dây và điện toán di động P8 ppt

... prediction model is used to determine whether a flow perceives aclean or dirty channel during each slot. (If the channel is dirty, we assume that the channelprediction model can also predict ... receive additional service only when leadingflows relinquish slots.As a consequence of its compensation model, CIF-Q provides a graceful linear degra-dation in service for leading flows. Additionally, ... given fair channel access, different users perceivedifferent rates of channel error and, hence, the actual throughput for different users is not8.5 ISSUES AND FUTURE DIRECTIONS191fair. In other...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P3 pptx

... and code division can be used in order to divide the radio spectrum. In fre-quency division, the spectrum is divided into frequency bands. In time division, the us-age of the channel is divided ... growth of radio traffic, and other fac-tors. A given radio spectrum (bandwidth) dedicated for cellular communications can bedivided into a set of disjoint and noninterfering radio channels. ... various parameters, leading to poor performance. Tabu search performs an ag-gressive exploration of solution space and directs the search in a desirable direction byavoiding inefficient paths....

Tài liệu Sổ tay của các mạng không dây và điện toán di động P6 ppt

... fixedAlgorithm complexity medium medium high highCommunication complexity low medium high mediumChannel utilization medium high medium highControl overhead medium high high mediumintroduced in Sections ... broadcast problem in mobile radio net-works, Distributed Computing 10, 3, 129–135, April 1997. 26. I. Cidon and M. Sidi, Distributed assignment algorithms for multihop packet radio networks,IEEE Trans. ... Timedivision duplexing (TDD) alternates transmission and reception at different time instantson the same frequency band, whereas frequency division duplexing (FDD) separates thetwo into different...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P11 ppt

... the same disk. Data items are then selectedfrom the disks for broadcast according to the relative broadcast frequencies assigned tothe disks. This is achieved by further dividing each disk into ... [38].11.2.1.3 Broadcast DisksA hierarchical dissemination architecture, called broadcast disk (Bdisk), was introducedin [1]. Data items are assigned to different logical disks so that data items ... relative broadcast frequencies of the disks. Conceptually, the disks can beconceived as real physical disks spinning at different speeds, with the faster disks placingmore instances of their...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P14 ppt

... approximate them to the average distance among all training data, (ii) calculate the dis-tances among the centers in each dimension and use some percentage of this distance for thescale factor ... sn, j = [1, n] determine the scalar dis-persion in each direction.To increase the functionality of the function f, we propose to use the Mahalanobis dis-tance in the Gaussian function. This ... (2) the net-work is nonparametric and makes more assumptions regarding the distribution of the inputdata than the static traditional methods (Bayesian); and (3) NNA is capable of creating de-cision...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P16 ppt

... muchsuperior for unit disk graphs.16.5 DISTRIBUTED ALGORITHMSTwo distinctly different distributed algorithms are described in this section. The first uti-lizes token passing to distribute the computation, ... consists of u and its distance-2 neighbors. The distance-2 degreeD(u) of u is the number of distance-2 neighbors of u, and the distance-2 degree D of a net-work, is the maximum distance-2 degree ... details. A distributed link scheduling algorithm under somewhat differentassumptions is given in [4].16.6.4 Unifying TDMA/CDMA/FDMA SchedulingFrequency division multiplexing (FDMA) and code division...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P26 ppt

... providing data to mobile appli-cations. We have described a cache maintenance (invalidation) strategy called AS for adistributed system that is predisposed to frequent disconnections. Such disconnectionshappen ... to follow an exponential distribution with mean 1/␮. Each MH generates aquery according to a Poisson distribution with mean rate of ␭. These queries are uni-formly distributed over all data ... Parallel and Distributed Systems, 9(4): 378–389,1998. 2. O. Wolfson and Y. Hang, Competitive analysis of caching in distributed databases, IEEE Trans-actions on Parallel and Distributed Systems,...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P1 pdf

... Usually, thehard handoff can be further divided into two different types—intra- and intercell handoffs.The soft handoff can also be divided into two different types—multiway soft handoffs andsofter ... strategies during overloading, might influence the overallperformance.In the next section, we introduce different types of possible handoffs. In Section 1.3,we describe different handoff initiation ... QHis filled.In this case, we consider the case for MO= 0. The two-dimensional state-transition dia-gram becomes one-dimensional ( j = 0). Therefore, the state probabilities can easily be...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P2 pdf

... traveledmaximal distance exceeds the last reported maximal distance. The paging operation isbased on the last reported cell and the maximal distance R. The system will search all Rrings surrounding the ... the cells within a distance of D from the lastreported cell. The distance-based strategy is dynamic, and the distance threshold D can bedetermined on a per-user basis depending on his/her mobility ... mobile station at and around its predicated location in descending probability un-til the mobile station is found. Their simulation results show that the predictive distance-based scheme performs...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P4 doc

... Unit Disk GraphsUnit disk graphs are intersection graphs of equal sized disks in the plane. It is easy to seethat given the distance model, multicoloring is equivalent to coloring for unit disk ... disk graph is the intersection graph of disks of equal diameter inthe plane. They can also be described in terms of distance or proximity models, whichconsist of a value d Ն 0 and an embedding ... of theFPA strategy discussed earlier has a performance ratio of k/2. In what follows, we discusssome specific classes of graphs that have been studied in the context of radio channel as-signment....

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