A new deterministic broadcast protocol for an ad hoc network is proposed in this paper which avoids re-computation of the transmission schedule, even when the topology of the network changes due to the mobility of the...
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Finding the location of an object, other than the sensor in a sensor network is an important problem. There is no good technique available in the literature to find the location of objects. We propose a technique to f...
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Fast and robust fingerprint matching is a challenging task today in fingerprint-based biometric systems. A fingerprint matching algorithm compares two given fingerprints and returns either a degree of similarity or a ...
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Fast and robust fingerprint matching is a challenging task today in fingerprint-based biometric systems. A fingerprint matching algorithm compares two given fingerprints and returns either a degree of similarity or a binary decision. Minutiae-based fingerprint matching is the most well-known and widely used method. This paper reveals a new technique of fingerprint matching, using an efficient data structure, combining the minutiae representation with the individual usefulness of each minutia, to make the matching more powerful. Experimental results exhibit the strength of this method.
There are several schemes for checkpointing and rollback recovery. In this paper, we analyze some such schemes under a stochastic model. We have found expressions for average cost of checkpointing, rollback recovery, ...
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Given a hexagonal cellular network with specific demand Vector and frequency separation constraints, we introduce the concept of a critical block of the network, that leads us to an efficient channel assignment scheme...
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Given a hexagonal cellular network with specific demand Vector and frequency separation constraints, we introduce the concept of a critical block of the network, that leads us to an efficient channel assignment scheme for the whole network. A novel idea of partitioning the critical block into several smaller sub-networks with homogeneous demands has been introduced which provides an elegant way of assigning frequencies to the critical block. This idea of partitioning is then extended for assigning frequencies to the rest of the network. The proposed algorithm provides an optimal assignment for all well-known benchmark instances including the most difficult two. It is shown to be superior to the existing frequency assignment algorithms, reported so far, in terms of both bandwidth requirement and computation time.
During recent years, the world is experiencing almost an exponential growth in the demand for various mobile communication services. On the other hand, the available bandwidth for such communication is very much limit...
ISBN:
(纸本)354000355X
During recent years, the world is experiencing almost an exponential growth in the demand for various mobile communication services. On the other hand, the available bandwidth for such communication is very much limited. As a result, efficient utilization of bandwidth for mobile communication has become more and more critical. When a mobile cellular network is designed, each cell of the network is assigned a set of channels to provide services to the individual calls of the cell. The task of assigning frequency channels to the cells satisfying some frequency separation constraints with a view to avoiding channel interference and using as small bandwidth as possible is known as the channel assignment problem. Three types of interference are generally taken into consideration in the form of constraints: i) co-channel constraint, due to which the same channel is not allowed to be assigned to certain pairs of cells simultaneously, ii) adjacent channel constraint, for which adjacent channels are not allowed to be assigned to certain pairs of cells simultaneously, and iii) co-site constraint, which implies that any pair of channels assigned to the same cell must be separated by a certain number. In its most general form, the channel assignment problem (CAP) is equivalent to the generalized graph-coloring problem which is a well-known NPcomplete problem.
This paper deals with the channel assignment problem (CAP) in a hexagonal cellular network with 2-band buffering, where the interference does not extend beyond two cells. Here, we first present new lower bounds on the...
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This paper deals with the channel assignment problem (CAP) in a hexagonal cellular network with 2-band buffering, where the interference does not extend beyond two cells. Here, we first present new lower bounds on the required bandwidth for a cellular network with homogeneous demand /spl omega/, for various relative values of s/sub 0/, s/sub 1/, and s/sub 2/, the minimum frequency separations required to avoid interference for calls in the same cell, or in cells at distances one and two respectively, where s/sub 0//spl ges/s/sub 1//spl ges/s/sub 2/. Next we present some novel strategies for assigning channels to the cells of the entire cellular network with a homogeneous demand w using a genetic algorithm. We then show how these strategies for homogeneous demand can be extended to the cases with nonhomogeneous demand vector W=(w/sub i/), where w/sub i/ represents the channel requirement for cell i. Most interestingly, it shows that in some cases depending on s/sub 0/, s/sub 1/ and s/sub 2/ the required bandwidth is mainly determined by the maximum demand w/sub max/ in W. It shows that in terms of bandwidth requirement the case is almost equivalent with cellular networks having homogeneous demand w/sub max/. The technique also results optimal bandwidth solutions for all the eight well-known benchmark instances including the most difficult two.
This paper focuses on the important issue of strategies for tracking users in a mobile communication network. Since the users are mobile, the network must keep track of where the users are, a prerequisite for routing ...
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This paper focuses on the important issue of strategies for tracking users in a mobile communication network. Since the users are mobile, the network must keep track of where the users are, a prerequisite for routing calls to the users. We assume that the mobile users periodically inform the network of their present location. Now, it is very important to decide an efficient location updation strategy that will optimize the overhead in terms of usage of radio spectrum and power, as well as the search cost for a mobile when a call is to be set up. Static location updation strategies often result in poor performance. Three dynamic location updation strategies have been considered, namely, the time-based strategy, the movement-based strategy and the distance-based strategy. A memoryless movement pattern on a two-dimensional mesh topology of cells has been studied. Analytical models have been developed to compare the performance of the strategies. Simulation studies also have been made for performance evaluation.
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